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Quinoa 417

5 kV ×7,000 2 μm AMRF, UCC
(a)

5 kV ×1,000 10 μm AMRF, UCC

(b)

Fig. 12.7 Confocal scanning laser microscope (CSLM) micrograph of (a) a peri-
sperm cell showing single starch grains, and (b) section of perisperm cell, showing

single and compound starch granules.

12.2 Chemical composition of quinoa seed

Quinoa grain is higher in protein, fat and fibre, and lower in carbohydrate
compared to other grains.The high protein content in quinoa, unlike cereals,
is explained by the high proportion of embryo (up to 30 % of the grain’s
gross weight, compared with 1 % for most cereals).

12.2.1 Carbohydrates
The major components of quinoa are carbohydrates, making up 60–74 % of
the dry matter (Kozioł M, 1992; Wright et al., 2002). Starch is about

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418 Cereal grains for the food and beverage industries

58.1–64.2 % of the dry matter (Repo-Carrasco et al., 2003), of which
≈10–21 % (depending on the variety) is amylose (Lorenz and Coulter, 1991;
Araujo-Farro et al., 2010). Granules of quinoa starch, located in the peri-
spem of the seed, have a polygonal form with a diameter of 0.4–2.0 μm,
being smaller than those reported for maize (1–23 μm) and for wheat
(2–40 μm). The extremely small size and high viscosity of the starch granule
can be beneficially exploited for specialized industrial applications (Galwey
et al., 1990), including those outside the food industry. Starches having
small-sized granules could serve as dusting starches in cosmetics and as
rubber tyre mould release agents. It is also possible to use it as a biodegrad-
able filler in polymer packaging (Ahamed et al., 1996a). In addition, accord-
ing to Araujo-Farro et al. (2006), quinoa starch is able to form transparent
edible biodegradable films without any chemical pretreatment. Its excellent
freeze–thaw stability makes it an ideal thickener in frozen foods and other
applications, where resistance to retrogradation is desired (Ahamed et al.,
1996b).

12.2.2 Dietary fibre
The dietary fibre in quinoa is mainly localized in the hull (seemingly seed
coat and pericarp) (Chauhan et al., 1992a). Its total dietary fibre content
varies betwen 2.0 and 2.2 % of the dry matter (Table 12.2), matching the
value reported for common grains and leguminous seeds (Frolich and Hes-
tangen, 1983; Varo et al., 1983). Additionally, more than 80 % of the fibre is
of the insoluble type (Ranhotra et al., 1993). Unlike soybean and peas,
quinoa grain is not a significant source of soluble fibre.

12.2.3 Protein
Wheat and oats come the closest to matching the protein content of quinoa
(Table 12.2), but cereals such as barley, corn and rice generally have amounts
of protein that are less than half that of quinoa. The protein content in
quinoa grains ranges from 7.47 % to 22.8 %, with an average of 15 % (Kozioł
M, 1992). The major seed storage protein of quinoa is an 11S-type globulin
called chenopodin (Brinegar and Goundan, 1993). Albumins and globulins
are the major protein fractions (44–77 % of total protein) while the percent-
age of prolamines is low (0.5–7.0 %) (Kozioł M, 1992).

The relative lack of the amino acid lysine is a major concern when cereal
grains (wheat and corn) are the main source of dietary protein. In contrast
to most plants, quinoa has an excellent balance of essential amino acids due
to the fact its amino acid spectrum is wider than that of other cereals and
legumes (Ruales and Nair, 1992a).The proteins are higher in lysine (5.1–
6.4 %) and methionine (0.4–1.0 %) than any other cereal (Table 12.3)
(Prakash and Pal, 1998). According to values indicated by FAO/WHO/
UNU (FAO/WHO/UNU, 2007), quinoa protein can supply around 180 %

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Quinoa 419

of the histidine, 274 % of the isoleucine, 338 % of the lysine, 212 % of the
methionine and cysteine, 320 % of the phenylalanine and tyrosine, 331 %
of the threonine, 228 % of the tryptophan and 323 % of the valine recom-
mended in protein sources for adult nutrition. Thus, quinoa appears to have
not only high protein content, but also a desirable amino acid composition
(Table 12.3). Methionine and cystine, the essential sulphur-bearing amino
acids which it contains, are also particularly important for vegetarian diets,
as well as correcting deficiencies in legume-based diets (Cusack, 1984).
Studies involving several commercial cultivars and land-race varieties have
demonstrated that the amino acid composition of the quinoa seed protein
is virtually identical to the FAO/WHO standard references pattern with no
deficiency in any essential amino acid (Gross et al., 1989). Viewing amino
acid profile and animal studies collectively, Ranhotra et al. (1993) conclude
that the quality of protein in quinoa equals that of the milk protein casein.
This means that supplementation of cereal grain with quinoa can effectively
enhance the protein quality of the resultant products. Quinoa may therefore
be considered one of the more promising food ingredients under investiga-
tion today, capable of complementing cereal or legume proteins. There is
also a potential for the production of protein concentrates from dehulled
quinoa seeds. The use of protein isolates based on quinoa has increased in
the food industry due to a several factors. These include their high protein

Table 12.3 Essential amino acids in quinoa and other foods and the recommended
requirements for adult humans

Amino acid FAO/WHO/
(g/100 g UNU adult
protein) Quinoa Corn Rice Wheat Bean Milk recommendationa

Adult

Histidine (His) 3.2 2.6 2.1 2.0 3.1 2.7 1.5
Isoleucine 4.9 4.0 4.1 4.2 4.5 10.0 3.0

(Ile) 6.6 12.5 8.2 6.8 8.1 6.5 5.9
Leucine (Leu) 6.0 2.9 3.8 2.6 7.0 7.9 4.5
Lysine (Lys) 5.3 4.0 3.6 3.7 1.2 2.5 2.2
Methionine
6.9 8.6 10.5 8.2 5.4 1.4 3.8
(Met)b
Phenylalanine 3.7 3.8 3.8 2.8 3.9 4.7 2.3

(Phe)c 0.9 0.7 1.1 1.2 1.1 1.4 0.6
Threonine
4.5 5.0 6.1 4.4 5.0 7.0 3.9
(Thr)
Tryptophan

(Try)
Valine (Val)

aScoring pattern for an ideal protein as reported by FAO/WHO/UNU (2007).
bMethionine + cystine.
cPhenylalanine + tyrosine.

Source: Koziol MJ (1992).

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420 Cereal grains for the food and beverage industries

levels and good functionality, as well as their low content of antinutritional
factors (Cordero-de-los-Santos, 2005).

12.2.4 Lipids
Oil content in quinoa ranges from 1.8 % to 9.5 %, with an average content
of 5.0–7.2 %, which is higher than that of maize (3–4 %) (Koziol MJ, 1992).
Saturated fatty acids make up approximately 11 % of the total fatty acid in
the seed. The predominant saturated fatty acid in quinoa seed described is
palmitic acid which amounts to approximately 8.5 % (Table 12.4). Minor
amounts of myristic, stearic, behenic and lignoceric acid make up the
balance of the saturated fatty acids. Linoleic, oleic and linolenic acid rep-
resent approximately 85 % of the total fatty acids. Linoleic acid is one of
the most abundant polyunsaturated fatty acids identified in quinoa; poly-
unsaturated fatty acids have several positive effects on cardiovascular
disease as well as improving the insulin sensitivity of patients (Abugoch
James, 2009). All fatty acids present in quinoa are well protected by the
presence of vitamin E, which acts as a natural antioxidant (Ng et al., 2007).
Quinoa oil contains notably high concentration of squalene, second only to
the pseudo-cereal grain amaranth (Table 12.5). Squalene is used as a bac-
tericide and as an intermediate in many pharmaceuticals, organic colouring
materials, rubber chemicals and surface-active agents.

Table 12.4 Seed fatty acid composition of quinoa compared to wheat

Component (%) Quinoaa Wheatb

Lauric acid (C12:0) – –
0.14 –
Myristic acid (C14:0) 8.5 26.0
– –
Palmitic acid (C16:0) – –
– –
Palmitoleic acid (C16:1) 0.66 1.4
23 21.0
Margaric acid (C17:0) 52.3 50.0
8.07 1.6
Heptadecenoic acid (C17:1) 0.56 –
1.66 –
Stearic acid (C18:0) 0.16 –
Oleic acid (C18:1 ω9) 0.98 –
Linoleic acid (C18:2 ω6) 1.89 –
Linolenic acid (C18:3 ω3) 0.45 –
Arachidic acid (C20:0) 0.21 –
Gadoleic acid (C20:1 ω9) 1.43 –
Eicosa dienoic (C20:2 ω6)
Behenic acid (C22:0)
Euric acid (C22:1 ω9)
Lignoceric acid (C24:0)
Nervonic acid (C24:1 ω9)
Others

aData obtained from Wood et al. (1993).
bData obtained from Chung et al. (2009).

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Table 12.5 Squalene content of quinoa and some
pseudo/cereals

Sample (%) Squalene (mg/100 g)

Quinoa 58.4 ± 0.69
Amarantha 430 ± 0.02
Buckwheat 1.9 ± 0.58
Barley 0.2 ± 0.08
Maize 1.6 ± 0.60
Millet 8.8 ± 0.80
Rye 0.3 ± 0.05
Spelt 2.0 ± 0.68

aGuil-Guerrero et al. (2000).
Source: Adapted form Ryan et al. (2007).

Table 12.6 Vitamin content of quinoa and some pseudo-cereals

Vitamin Quinoa Amaranth Buckwheat Wheat Barley

Ascorbic acid (C) n.r 4.20 n.r n.r n.r
0.36 0.11 0.10 0.42 0.37
Thiamin 0.32 0.20 0.42 0.12 0.11
0.77 1.46 1,23 0.95 0.14
Riboflavin (B2) 1.50 0.93 7.02 6.73 6.27
Pantothenic acid 0.49 0.59 0.21 0.42 0.40
82 30 43 8
Niacin 184 2 0 0 n.r
14 1.19 n.r. n.r. 0.57
Vitamin B6 2.44
Folate (total)a 0.96 n.r. n.r. n.r.
Vitamin Ab 0.08 0.19 n.r. n.r. n.r.
4.55 0.69 n.r. n.r. n.r.
Vitamin E – 0.35
α-tocopherol

β-tocopherol
γ -tocopherol
δ-tocopherol

aμg 100 g−1.
bInternational units.

n.r. = not reported.

12.2.5 Vitamins
Vitamins are compounds essential for the health of humans and animals.
Quinoa is found to be rich in niacin, folic acid, vitamins A, B2 and E when
compared to some of the most common cereals (wheat and barley). Quinoa
also satisfies the requirements for vitamin A, E, B6, thiamine, riboflavin, and
folate recommended by the Committee on Dietary Allowances for infants
(National Research Council, 1989a; Ruales and Nair, 1993a). The process
of removing saponins, which is essential to make the grain suitable for
human consumption, seems to alter the vitamin composition of quinoa to
a minor degree (Ruales and Nair, 1993b). Table 12.6 shows the vitamin
composition of quinoa compared to that of some other grains.

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422 Cereal grains for the food and beverage industries

A study conducted by Schoenlechner et al. (2010) has shown that pseudo-
cereals present a valuable alternative for increased folate intake. The folate
content in quinoa is concentrated in the bran fraction which alone contains
about 177.6 ± 20.6 μg of folate/100 g dm (dry matter). In spring wheat, the
highest folate content was also detected in the bran fraction but at much
lower concentrations than in quinoa (18.6 ± 1.9 μg of folate/100 g dm). With
these values in mind, it can be postulated that quinoa can be considered a
substantial source of folate, particularly suitable for dietetic products which
are known to be characterized by low folate contents, one example being
gluten-free products. Recently, it was shown that coeliac patients consuming
gluten-free products have a daily folate intake of 186 μg for women and
172 μg for men (Hallert et al., 2002), which is much lower than recom-
mended daily intake of 400 μg for women in fertile age and 300 μg for other
adults (Becker et al., 2004). Folate deficiency is connected to high homo-
cysteine levels that are suspected to increase the risk of coronary diseases.
The most importance aspect of folate is its role in the prevention of neural
tube defects in the foetus (Pitkin, 2007). Yazynina et al. (2008) showed that
the folate content in gluten-free products, such as bread and rolls (39.5
± 0.6 and 15.1 ± 0.6 μg of folate/100 g fresh weight, respectively) was lower
than in their gluten-containing counterparts. Therefore, fortification of
gluten-free products with folic acid or enrichment of these products with
nutrient-dense fractions of cereals naturally free from gluten and high in
folate, such as quinoa, is of significant interest.

12.2.6 Minerals
The ash content of quinoa (3 %) (Valencia-Chamorro, 2004) is higher
than that of rice (1 %), wheat (2 %) and other traditional cereals (Table
12.3), which is due to the fact that quinoa grains contain large amounts of
minerals such as Ca, Fe, Zn, Cu and Mn (Repo-Carrasco et al., 2003; Dini
et al., 2005). Levels of Ca, Zn and Fe are significantly higher than in most
commonly used cereals (Table 12.7). Iron originating from quinoa has been
reported to be highly soluble and thus could be easily available to a section
of the population suffering from anaemia (Valencia et al., 1999).

12.2.7 Polyphenol compounds
According to Gallagher et al. (2010), the flavonols quercitin and kaempferol
glycosides are the most abundant polyphenols in quinoa seeds, with a con-
centration of 36.7 and 40.2 μmol/100 g, respectively (dry weight base). Poly-
phenols are bioactive compounds known to decrease disease associated
with oxidative stress such as cancer and cardiovascular disease (Scalbert
et al., 2005). Gallagher et al. (2010) also report that the total phenol content
was doubled following a sprouting process representing, thus, a potential
rich source of polyphenol compounds for enhancing the nutritive properties
of food products.

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Table 12.7 Mineral content of quinoa seed (mg/100 g dry weight) as compared to
other cereals

Mineral Quinoaa Barley Ryeb Wheatb

Calcium 110 88c 49 48
Magnesium 42.7 145b 138 152
Zinc 4.8
Copper 9.5 1.5c 2 3.3
Phosphorus 360 0.7b 0.7 0.6
Iron 9.2 420c 428 387
5c 4.5 4.6

aChauhan et al. (1992a).
bRepo-Carrasco et al. (2003).
cBhargava et al. (2006).

12.2.8 Antinutritional factors in quinoa seed
Antinutritional factors (ANFs), by definition, are those biological com-
pounds present in human or animal foods that reduce nutrient utilization
or food intake, thereby contributing to impaired gastrointestinal and meta-
bolic performance (Dunlop, 2004). Several antinutritional factors have been
found in quinoa, such as saponins, tannins, protease inhibitors and phytic
acid, which can exert a negative effect on the performance and survival of
monogastric animals when it is used as the primary dietary energy source
(Nsimba et al., 2008). However, the phytate content of quinoa grain does
not differ from that of the other cereals such as wheat, rice, rye, oats and
barley (Ahamed et al., 1998; Belitz et al., 2009).

Saponins
Saponins are the principal ANFs present in the seed coat of quinoa. Most
saponins are nitrogen-free glycosides, each consisting of a sapogenin and a
sugar. The sapogenin may be a steroid or a triterpene, and the sugar moiety
is generally glucose, galactose, pentose or methyl pentose (Stecher et al.,
1960). These saponins are responsible for the characteristic astringent or
bitter taste associated with quinoa (Tarade et al., 2006). To be edible, the
saponin must be removed from the quinoa seeds. Traditionally, saponin has
been removed by laboriously hand scrubbing the quinoa with alkaline
water. The saponin content is checked by placing the grain in a tube, adding
water and vigorously shaking for 30 s. If no foaming occurs, all saponins are
assumed to have been removed. Additionally, saponin content can poten-
tially be reduced through either an extrusion or a roasting process (Karwe
et al., 2007). Quinoa can be classified via its saponin content, which is depen-
dent on the quinoa variety: ‘sweet’ (free from or containing <0.11 % of free
saponins) or ‘bitter’ (containing >0.11 % of free saponins) (Kozioł MJ, 1992;
Gee et al., 1993; Soliz-Guerrero, 2002; Stuardo and San Martın, 2008;
Martınez et al., 2009). Generally, the saponin content in seeds of sweet

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424 Cereal grains for the food and beverage industries

genotypes varies from 0.2 to 0.4 g/kg dry matter and in bitter genotypes
from 4.7 to 11.3 g/kg dry matter (Mastebroek et al., 2000). Some experts
have called for the development of saponin-free strains of quinoa since the
saponin removal process has limited the production and marketing of this
crop. Ecologists observe, though, that the bitter-tasting saponin probably
prevents insect and bird predation so its removal might lead to increased
reliance on insecticides. Saponin-free varieties do already exist (Koziol,
1990, Kozioł M, 1992) such as the one planted in southern Bolivia (S. Juan
Altoplano).

Although saponins were found to be the primary antinutrient and flavour
factors associated with quinoa, they also have some interesting biological
properties: they can (i) increase the permeability of the small intestinal
mucosal cells, facilitating the uptake of materials to which the gut would
normally be impermeable such as drugs (Oakenfull and Sidhu, 1990; Gee
et al., 1993); (ii) exert antifungal activity due to its capacity to associate with
steroids of fungal membranes, causing damage to its integrity and pore
formation (Armah et al., 1999); and (iii) lower blood cholesterol levels
(Oakenfull and Sidhu, 1990). Saponins also have immense industrial impor-
tance and are used in the preparation of soaps, detergents, shampoos, beer,
fire extinguishers and in the photography, cosmetic and pharmaceutical
industries (Johnson et al., 1993). Moreover, saponins are being studied for
their insecticidal, antibiotic and fungicidal properties and are seemingly free
from significant oral toxicity in humans (Dini et al., 2001).

Phytic acid
Phytic acid is found in most cereals (Hallberg et al., 1987) and legumes at
concentrations of 1–3 % dry matter. It is also found in some fruits and
vegetables. Phytic acid is not only present in the outer layers of quinoa, as
in the case of rye and wheat (Ahamed et al., 1998) but is also evenly dis-
tributed within the endosperm. Phytic acid binds minerals, such as Fe, Zn,
Ca and Mg, and can make the mineral content of a cereal inadequate
(Khattak et al., 2007), especially for children. Ranges of 10.5–13.5 mg/g of
phytic acid for five different varieties of quinoa were reported by Kozioł
MJ (1992) (Table 12.8).Valencia et al. (1999) studied the effect of different
processing techniques (germination, lactic acid bacteria (LAB) fermenta-
tion, cooking and soaking) on in vitro iron availability and phytate hydro-
lysis in high- and low-saponin quinoa. They found that the level of phytate
and its degradation products could be reduced by 4–8 % through cooking,
by 35–39 % through germination, by 61–76 % after soaking and by 82–98 %
by using LAB fermentation.The highest reduction, about 98 %, was obtained
after fermentation with Lactobacillus plantarum of a germinated flour. Iron
solubility increased, two to four times after soaking and germination, three
to five times after fermentation and five to eight times after fermentation
of the germinated flour samples and was highly correlated to the reduction
of phytate. On the other hand, cooking had no effect on the amount of

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Table 12.8 Antinutrient (saponins, phytic add, and tannins) contents of quinoa
seeds compared with those of other seeds

Seed Saponin Phytic acid Tannins Trypsin units
(mg/g) (mg/g) (%) inhibited (mg)

Quinoa, whole raw 9.0–21 10 0.5 1.4–5.0
Quinoa polished 3.0 ND ND ND

and washed raw Traces 5–6 0.04–0.13 0.5
Amaranthus
4–6 8 0.05 24.5–41.5
paniculatas
Soya bean (Glycine 4 8–12 1.02 12.9–42.8

max) NA 8 NA 17.8
Kidney bean
ND 12.4 ND ND
(Phaseolus max) ND 12.9 ND ND
Lentils (Lens ND 11.8 ND ND
ND 11.9 ND ND
esculenta) 1a 11.3 ND ND
Wheat ND 9.2 ND ND
Triticale
Rye
Barley
Oats
Corn

aOat bran.
NA = not available, ND = not detected.
Sources: Ahamed et al. (1998), Belitz et al. (2009).

soluble iron. Additionally, there was no difference between the quinoa
varieties with regard to phytate reduction and iron solubility.

Protease inhibitors
Protease inhibitors, broadly distributed in nature, are proteins that form
stable complexes with proteolytic enzymes (Aguirre et al., 2004). In quinoa
seeds, the concentration of protease inhibitors is less than 50 ppm (Ahamed
et al., 1998). In more detail, trypsin inhibitor units of quinoa are much lower
than those in commonly consumed grains (Ahamed et al., 1998) and hence
do not pose any serious concern.

12.3 Quinoa milling and applications in foods
and beverages

Quinoa can be milled and the resulting flour used to make a variety of food
products and baked goods. It is also used for brewing purposes.

12.3.1 Milling
Usually, quinoa gain is processed by means of soaking, rubbing, rinsing and
boiling in the domestic setting. Industrially, it is processed by means of wet

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426 Cereal grains for the food and beverage industries

and dry milling (Becker and Hanners, 1990). Due to its very small size, the
quinoa grain is generally milled whole, after removal of the saponins.
Whole-grain quinoa flour either includes the pericarp if the saponins are
washed out before milling, or some or none of pericarp if saponins are
removed by abrasion. The production of quinoa flour fractions with differ-
ent chemical composition has been only poorly investigated. As the sapo-
nins are concentrated in the hulls, their content can be minimized by
dehulling of the seeds (Reichert et al., 1986). A laboratory roller mill has
been used by Chauhan et al. (1992a) to separate the bran fraction from the
flour fraction. The bran fraction was very high in protein (20.4–24.3 %) and
fat (11.0–13.2 %) and accounted for some 40 % of the dehulled grain,
whereas the flour fraction that accounted for 50 % of the dehulled grain
was carbohydrate (starch)-rich (73.8 %) and protein-poor (only 6.5 %). This
finding can be explained in terms of the bran being mainly embryo material
and flour being mainly perisperm. Becker and Hanners (1990) used three
quinoas (low, medium and high saponin content) and a Morehouse Model
350 stone mill to evaluate saponin removal.The stone mill removed 33–40 %
of the seed as bran fraction. Moisture tempering the grain from 8 to 16 %
did not improve milling yield or mill fraction composition. The mill fraction
typically contained less than 0.3 mg/g of saponin and residual bran was left
on the grain.

Caperuto and colleagues (2001) used a Senior Quadrumat Brabender
mill to produce quinoa flour. Grain preconditioned at 150 g/kg moisture
yielded the highest recovery of break plus reduction flour with an average
particle size of 187.7 μm. However, the protein content of the flour fell from
125 g/kg of dry matter (dm) in the wholemeal to 35.5 g/kg of dm in the
flour. On the other hand, the protein was not greatly impoverished in lysine,
and an increase in methionine and branched-chain amino acid contents was
observed. Nevertheless, the extremely high loss of grain via mechanical
milling indicates an area of research which needs more work.

12.3.2 Quinoa applications: an introduction
Quinoa has a variety of uses in foods and feeds and also has other non-food
industrial uses. Both the seeds and the leaves of the quinoa plant can be
eaten. The leaves are typically cooked and served as a side dish, similar to
spinach or beet greens. As a whole-grain, quinoa may be incorporated into
several food products such as breakfast cereals, biscuits, beer, bread and
soups (Weber, 1978). These grains can also be boiled and made into pastas
(Table 12.9).When cooked, they remain separate, fluffy and chewy, and have
a nut-like flavour. In Peru and Bolivia, quinoa flours, flakes, tortillas, pan-
cakes and puffed grain are produced commercially (National Research
Council, 1989b). The fact that quinoa does not have gluten-forming protein
opens up opportunities for the parts of the food industry serving consumers
suffering from coeliac disease (CD).

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Table 12.9 Possible utilization of quinoa seeds

Processed foods

Soup, salad, casseroles, chilli, and stew, as well as roasted and ground in several
kinds of desserts (Chile, Peru, Bolivia and Ecuador)

Rice replacement, hot breakfast cereal, boiled in water to make infant food,
popped like pop corn.

Quinoa flakes, tortillas, pancakes, puffed grains
Breada (up to 20 % of quinoa flour)
Pastaa (up to 30–40 % of quinoa flour)
Crackersa
Sweet biscuits (up to 60 % of quinoa flour)
Pastry (up to 50 % of quinoa flour)
Low-fat, fried noodle-like snacks (blends of quinoa starch and soya bean protein

isolate)
Gluten-free pasta and bread
Malted drinks formulation (Chicha)
Complementary protein for improving amino acid balance
Tempeh (solid-state fermentation with Rhizopus oligosporus) (similar to tofu)

Agro-pharmacological and cosmetics industrial uses

Starch (plastic bags, insect repellent, dusting powders, thickener in frozen foods)
Saponins (insecticide, fungicide, antibiotics, mediator of intestinal permeability,

shampoo, clothes, fire extinguisher, photo processing)
Analgesic
Disinfectant of the urinary tract

Note: In Bolivia, in 1975 the government adopted a resolution mandating that 5 % of quinoa
flour must be added to all pasta, bread and cracker products.
Sources: Bhargava et al. (2006), Valencia-Chamorro (2004), Ahamed et al. (1998), Repo-
Carrasco et al. (2003), Jacobsen (2003), Vega-Galvez et al. (2010).

12.3.3 Instant infant porridge
In 2002, Ruales and colleagues developed an instant quinoa infant porridge
that met the energy requirements for children (Ruales et al., 2002). This
latter is produced as follows: after removal of the saponins and cleaning the
grain, quinoa is precooked with hot water then drum dried. It is then milled
into a shelf-stable flour. The consumer reconstitutes the flour into porridge
by mixing it with boiling water (Taylor and Parker, 2002). Nowadays, several
multigrain infant cereals including quinoa are on the market. For example,
Bobobaby Inc. produces ‘seven months +’ Quinoa and mixed vegetables
grain (www.bobobaby.com), Babynat organic produces organic infant cereal
with fruit and quinoa (www.babynat.co.uk).

12.3.4 Tempeh
Tempeh is produced by solid-substrate fermentation of pulses and legumes
by the fungus Rhizopus oligosporus Saito and originated in Indonesia

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428 Cereal grains for the food and beverage industries

(Peñaloza et al., 1992). Peñaloza et al. (1992) successfully produce quinoa
tempeh using cooked wholegrains of both sweet and bitter quinoa varieties,
after the saponins had first been removed by scarification. No sensory data
was available; however, the investigators implied that appearance, flavour
and texture, which were subjectively assessed, were acceptable.

12.3.5 Snack food
A research project in India investigated the use of quinoa starch blended
with soy flour to produce a deep-fried dry noodle product used as a snack
food ingredient (Ahamed et al., 1997). They found that amaranth and
quinoa starch have a great effect in reducing oil absorption during the deep
frying process and therefore the oil content of fried foods. Lorenz and
Coulter (1991) successfully extruded blends of quinoa (10–30 %) and maize
to produce snack-type products. The great advantage of compositing maize
with quinoa is that the protein nutrition value of the maize can be improved.
In more detail, at a 30 % quinoa addition level, lysine was increased by 50 %.
The popped quinoa can be used as a snack food or as a garnish, particularly
for salads. Popped quinoa does not appear to have been addressed in the
scientific literature.

12.3.6 Baked goods
Quinoa can be used as wheat flour substitute for enriching unleavened
bread, cake and cookies. A coarse bread called kispina was produced in
South America at one time (Coulter and Lorenz, 1990). Since quinoa grain
is gluten-free, wheat flour must be added to it to make leavened bread.
Lorenz and Coulter (1991) have perhaps best documented some of the
issues related to the use of quinoa in baked products. They produce quinoa
flour, from variety D407, by first removing the pericarp using a barley
pearler and then milling the dehulled quinoa in an Udy cyclone mill. Bread
made by replacing 5 % of the bread flour with quinoa flour resulted in a
volume increase, which was probably due to rather high α-amylase activity
characterizing the D407 quinoa flour (Lorenz and Nyanzi, 1989). Higher
α-amylase activity increases the amount of fermentable sugars produced
from starch. This reaction causes increased gas production and slightly
higher load volume (Lorenz and Coulter, 1991). Bread made with up to
10 % quinoa flour was judged acceptable considering all external and inter-
nal bread characteristics. With higher levels of replacement, bread loaf
volume decreased (mainly due to a gluten dilution effect) and the crumb
colour of the breads became darker with a distinct bitter aftertaste (Fig.
12.8). Chauhan et al. (1992b) investigated the baking performance and
overall acceptability of quinoa/wheat breads produced using either quinoa
flour or quinoa meal. In general, breads with 10 % of water-soaked quinoa
meal were more acceptable compared to other quinoa variations.

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Quinoa 429

0% 5% 10%

20% 30%

Fig. 12.8 Breads baked with 5, 10, 20 and 30 % of quinoa flour. Reprinted from
Lorenz and Coulter (1991) with the permission from Springer.

Similarly, up to 10 % quinoa flour resulted in acceptable and pleasant
cake products (Lorenz and Coulter, 1991). Chlorinated wheat flour improves
both the colour and baking properties and is used in the commercial pro-
duction of ratio cakes (those with high proportions of sugar and liquid in
the recipe), but chlorination of the quinoa flour did not substantially
improve cake characteristics. Cookie spread and top grain scores decreased
with increasing levels of quinoa flour blended with high-spread cookie flour.
Flavour improved up to 20 % quinoa flour in the blend. The flavour was
described as nutty. The nutty taste was presumably a result of Maillard
browing reaction, due the high lysine content of the quinoa flour. However,
at the 30 % level of quinoa in the blend with the high-spread cookie flour
a bitter aftertaste was noted. Additionally, cookie spread was considerably
improved by the addition of 2 % lecithin, as emulsifier (Lorenz and Coulter,
1991).

12.3.7 Pasta, noodles and other foods
The nutritive value of wheat flour noodles can also be considerably enhanced
by using up to 40 % quinoa flour, without affecting appearance or other
characteristics of the end-product. Caperuto et al. (2001) produced gluten-
free spaghetti with quinoa. The spaghetti blend was composed of quinoa
flour (10 %), maize flour, with either egg albumen or β-glucan (Curdlan) as
binder. The process involved subjecting the ingredient mixture to direct
steam to gelatinize the starch, then extruding the dough in a pasta extruder.
The spaghetti had reasonable physical properties in comparison to soft
wheat spaghetti and was accepted by a consumer sensory panel. Even at

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430 Cereal grains for the food and beverage industries

the low level of quinoa addition used, the lysine and methionine content
were significantly improved in comparison with maize protein. Additionally,
the manufacture of quinoa spaghetti, using different percentages of
methylcellulose sodium salt (CMC) (0.1 %, 0.2 % and 0.3 %) and pregela-
tinized starch (10 %, 20 % and 30 %) as structuring agents was performed
by Del Nobile and colleagues (2009). They found that when CMC was
added to quinoa-based dough, the elongation and share viscosity declined.
Moreover, the stress at break for dry non-conventional spaghetti decreased
for quinoa spaghetti to CMC and pregelatinized starch was added. Finally,
the CMC and pregelatinized starch were shown to strongly affect the senso-
rial parameters of dry and cooked quinoa spaghetti. Several companies
currently distribute pasta products that include quinoa as an ingredient.
Quinoa Corporation (Gardena, CA, www.quinoa.net) sells pasta (linguine,
rotelle, shells, spaghetti and veggie curls) made from a corn–quinoa blend.
Northern Quinoa Corporation (Kamsack, SK, www.quinoa.com) distrib-
utes milled quinoa, quinoa flour and pasta (spaghetti, fettucine, spirals,
elbows) made from a rice–quinoa blend. Finally quinoa’s qualities are so
polyvalent that it has also become an exotic alternative for vegetarian con-
sumers. This has led an English company to produce a chilled quinoa meat
substitute called ‘Quinova’ and a Spanish company to produce quinoa milk
(Abugoch James, 2009).

12.3.8 Quinoa beverages
Quinoa has a high proportion of d-xylose (120 mg/100 g sample), maltose
(101 mg/100 g sample) and fructose (19.6 mg/100 g of sample), suggesting
that it would be a useful ingredient in malted drink formulations
(Ogunbengle, 2003). Malting and fermentation are among the traditional
food-processing technologies known to have beneficial effects on the func-
tional and organoleptic properties of many grains. Malting is the controlled
germination followed by controlled drying of the kernels. The main objec-
tive of malting is to promote the modification of the grain structure
(Fig. 12.9) and chemical composition by means of the grain’s endogenous
enzymes, which are not present in non-germinated grain. Fermentation
involves modification of the grain structure and composition through the
action of microbes, often LAB and/or yeast, using the grain as substrate
either in liquid slurry or in solid state. The malting process increases the
α-amylase activity of quinoa grain and reduces the phytate content of the
grain, thus improving the availability of minerals (see Section 12.4.6).
Quinoa grains are fermented into a beer called chicha blanca (Simmonds,
1965) which is considered to be the ‘drink of the Incas’. It is produced
among the Indians of the Andes by pre-chewing quinoa, maize or yuca.
Salivary diastase is the amylolytic agent. Well-made chichi is an attractive
beverage, clear and effervescent, resembling apple cider in flavour. In
general, it contains 5 % or less ethanol with a range of 2–12 % (Cutler and

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Quinoa 431

E F
WS

K

Perisperm

5 kV ×35 500 μm AMRF,
(a)

5 kV ×35 500 μm AMRF, UCC

(b)
Fig. 12.9 SEM micrography of unmalted (a) and malted (b) quinoa kernel.

Cardenas, 1947). Moreover, in the highlands and valleys of Bolivia there is
a non-alcoholic beverage called Chicha de quinoa, or aloja, that is usually
merely water in which quinoa has been boiled. Sometimes sugar and cin-
namon are added (Cutler and Cardenas, 1947).

Zarnkow et al. (2007) used the response surface methodology to inves-
tigate the influence of the three malting parameters – degree of steeping,

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432 Cereal grains for the food and beverage industries

germination time and temperature – on the quality of quinoa malt to use
as a raw material for gluten-free foods and beverages. They found that the
optimal malting programme was achieved with a germination time of
five days, 46 % degree of steeping and a 15 °C steeping and germination
temperature. The quinoa malt showed good extract yields and protein
solution properties. The red colour of the mash can be attributed to the
β-cyanin pigment (Mabry et al., 1963) as well as the high zinc content
(Whali, 1990). Quinoa malt also has the highest final attenuation of all the
pseudocereals. Quinoa beer was produced by Zweytick et al. (2005) and
was slightly opaque with a yellow colour. The foam stability was quite
good and the taste was very acceptable. Quinoa represents a very interest-
ing alternative adjunct for brewing purposes considering the current diffi-
culties in world grain supply. Exogenous enzymes can also play a major
role in ensuring extractability of quinoa for brewing purpose (Lalor and
Goode, 2010).

12.4 Conclusions

The nutritional excellence of quinoa has been known since ancient times
in the Inca Empire. Nowadays, quinoa has again been recognized all over
the world for its nutritional benefits which arise from its composition and
the beneficial minor components present in the grain (dietary fibre, resistant
starch, minerals, vitamins, phenols). It holds exceptional promise as a
weaning food for infants, especially in nutritionally-deficient areas of the
developing world. Quinoa also seems to induce a lower desire to eat,
increase fullness, satiety sensation, and higher palatability score than other
gluten-free foods (Berti et al., 2004, 2005). However, further research into
quinoa breeding is needed in order improve the adaptability of different
cultivars to ‘new homes of quinoa’ such as in the USA and Europe. In more
detail, the basic objective of quinoa breeding is the development of a variety
with high grain yield accompanied by a high protein and low saponin
content. This would make the cost of producing quinoa more competitive,
which would result in a sales price that would be more commercially com-
petitive compared to those of wheat, rice and barley.

12.5 Future trends

The need for intensive cultivation of quinoa should be emphasized as this
could meet quality and quantity needs expressed by the food industry. As
a crop that is both healthy and sustainable, quinoa meets the needs of con-
sumers who are increasingly seeking products of this type (Fonte, 2002). To
improve the popularity of quinoa, efficient dissemination of information
about the crop among consumers is required, together with proper

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marketing and more efficient post-harvest technologies. Considering the
nutritional excellence and the functional properties, quinoa has the poten-
tial to become the food crop of the 21st century.

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13

Amaranth

DOI: 10.1533/9780857098924.439

Abstract: Amaranth has attracted a great deal of interest in recent decades due to
its valuable agricultural, nutritional and functional characteristics. Amaranth is a
pseudo-cereal crop, producing cereal-like grains containing an unusual type of
starch, high-quality oil and high levels of nutritionally favourable proteins, and it
represents a suitable foodstuff for patients with gluten intolerance. Due to the
content of potential health-promoting compounds such as rutin and nicotiflorin,
amaranth is considered a ‘natural biopharmaceutical’ plant that could increase
human health. Grain amaranth is being developed as an energy food to be
combined with traditional cereal grains in breakfast foods, bread, multigrain
crackers, pastes and pancake mixes, or popped as a snack food product. However,
intense and continuous research efforts are still necessary in several areas, such
as amaranth breeding and field cultivation, relevant food and feed processing
technologies, product development, product commercialization and marketing.

Key words: amaranth, chemical composition, amaranth utilization in food and
beverages.

13.1 Introduction

Amaranthus is a genus (family Amaranthaceae) consisting of more than 50
species, some of which are cultivated for use as cereals, vegetables and
ornamentals, and others of which are considered weeds. Amaranth grain
was once a staple food of the Aztecs and is now finding its way into baked
goods and breakfast cereals in other parts of the world. It was cultivated
on a large scale in Mexico and Central America until the early sixteenth
century. The religious use of amaranth in Aztec culture was seen by the
Spanish conquistadores as a dangerous imitation of the rituals of the Catho-
lic Mass, and its cultivation was therefore prohibited and the cult was
banned. Before the recent resurgence of interest in the crop, grain amaranth
was cultivated on a small scale by small farmers in the remote villages of
Mexico, Guatemala, Peru, northern India and Nepal, and vegetable ama-
ranth was grown in China, Southeast Asia, southern India, West Africa and
the Caribbean basin. Grain amaranth has recently come to be considered

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440 Cereal grains for the food and beverage industries

as a promising food crop owing to its resistance to stress (drought, disease,
salinity, alkalinity, acidic or poor soil) and high potential for biomass and
grain yield. It is cultivated as a minor crop in Central and South America
and some areas of Asia and Africa. This chapter focuses on grain amaranth,
rather than vegetable amaranth.

Amaranth is a pseudo-cereal crop, producing cereal-like grains contain-
ing high levels of nutritionally favourable proteins (they have an amino acid
composition close to the ideal protein (Yanez et al., 1994), an unusual type
of starch and high-quality oil. It is classified among the pseudo-cereals also
due to its content of saccharides (62.0 %), which is slightly lower of that of
common cereals albeit with a higher digestibility.Amaranth flour represents
a suitable foodstuff for patients with gluten intolerance and additionally
amaranth consumption positively affects plasma lipid profiles and leads to
a reduction in cholesterol levels (Escudero et al., 2004). Amaranth oil, which
contains high levels of unsaturated fatty acids and squalene, is also an effec-
tive natural antioxidant supplement (Martirosyan et al., 2007). Squalene
(2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22- tetracosahexaene) is a biosyn-
thetic precursor to all steroids (He et al., 2002). Recently, the genus Ama-
ranthus has been reported to have antimalarial and antiviral properties
(Hilou et al., 2006; Roy et al., 2006). Amaranth pectin, a gel-forming com-
ponent, can also be used to bind toxic and radioactive metals and remove
them from the human body (Cai et al., 2003), and the red-coloured vegeta-
tive tissue produces high levels of β-cyanin pigments that can be used as
natural food colorants.

Although the market demand for amaranth has been changeable over
the last decades, the use of the crop for breakfast cereals, snack foods and
multigrain bread products has been steady. Generally, amaranth products
are sold in speciality/organic food stores, in the health food section of
grocery store, or through direct marketing (Myers, 1996; de la Barca et al.,
2010a). Amaranth is extremely adaptable to adverse growing conditions,
has no major disease problem and is among the easiest of plants to grow.
Moreover, due to the content of potential health-promoting compounds
such as rutin and nicotiflorin and peptides with anticarcinogenic (Myers,
1996) and antihypertensive activities (Silva-Sánchez et al., 2008), amaranth
is considered a ‘natural biopharmaceutical’ plant that could increase human
health. For these reasons, amaranth has been attracting worldwide attention
as a high potential new crop with multiple uses.

13.1.1 Production area, price and yield
As mentioned previously, amaranth was a major crop for the pre-
Columbian cultures in Latin America, but amaranth consumption and cul-
tivation was suppressed after the Spanish conquest, and thereafter only
continued on a small scale. Levels of amaranth cultivation remain very low.

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Amaranth 441

Indeed data on cultivation levels is not published by the FAO, although
appreciable commercial cultivation of amaranth for human nutrition does
in fact take place. A much larger number of farmers around the world have
begun to grow amaranth (http://www.jeffersoninstitute.org/amaranth.php)
since the 1990s. Beside Latin American countries, the crop is produced in
the USA, India, Africa, China and Eastern Europe and Russia. The cultiva-
tion of amaranth to use the grain or leaves as food has also become estab-
lished in Africa and Nepal, and it is a re-emerging crop in Mexico. Since
the 1980s, grain amaranth has been grown commercially in the USA with
a fair degree of success (Baker and Rayas-Duarte, 1998b; Wu and Corke,
1999). At around the same time the Chinese Academy of Agricultural
Science introduced the grain to China from the USA (although vegetable
types had been planted in China for centuries) (Wu and Corke, 1999).

The total US acreage for the last decade has been very small, typically
in the 1500–3000 acre (607–1214 ha) range (Hackman and Myers, 2003).
Although the USA has been the leading producer of grain amaranth for
use in retail food products, the largest production area from 2001–2010 is
believed to have been China (Rastogi and Shukla, 2011). The main Chinese
use of amaranth is reportedly as swine feed, rather than harvesting the grain
for human use (Myers, 1996; Rastogi and Shukla, 2011).

Concerning the yields per hectare which can be achieved by grain ama-
ranth, there are few data in the literature. Yield levels are often between
500 and 2000 kg ha−1, but with good agronomic practices, up to 3000 kg ha−1
can be obtained (Williams, 1995). Lee et al. (1996) report usable yields of
2100–2500 kg ha−1 during cultivation trials in Germany. Also Myers (1994)
reported that yields of more than 1000 kg ha−1 have been reached in many
research plots throughout the USA, but replicated yields of more than
3000 kg ha−1 have been achieved in some locations only. In Montana USA,
4000 kg ha−1 has been obtained and in Peru 6000 kg ha−1. In Southern Italy,
yields of 22 amaranth entries varied between 1200 and 6700 kg ha−1, the
latter belonging to A. caudatus (Alba et al., 1997). There was an average
yield of 2250 kg/ha in the northwest hills of India and 2000 kg ha−1 in
Austria (Williams, 1995). From the Slovak Republic, average grain yields
were between 2100 and 2700 kg ha−1 (Jamriška, 1996, 2002). In China,
depending on environmental conditions and cultivation systems, field pro-
duction may yield around 2200–5500 kg ha−1 of amaranth grain (Cai et al.,
2004).The average amaranth yield is about 1000 kg ha−1 even if 3000 kg ha−1
has been achieved in small research test plots in a few locations. Although
it is not unusual for amaranth to be almost totally lost at harvest due to
shattering and/or lodging, with a yield of 1000 kg ha−1 and a market price
around $1.00/kg, amaranth can represent a profitable crop for farmers.

A yield of 3000 kg ha−1 is small compared to other crops such as sorghum
or maize, but for a crop with a protein level similar to that of wheat, a yield
of 3000 kg ha−1 would be decent, although not exceptional (Cai et al., 2004).

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442 Cereal grains for the food and beverage industries

13.1.2 Phytology, classification and cultivation
From a botanical point of view, amaranth is assigned to the family of the
dycotiledonous Amaranthaceae (Table 13.1), which are assigned to the
family of the monocotyledonous grasses (Pomaceae). Although the 60
species of genus Amaranthus are native to many parts of the world, most
are considered weeds, and only about a dozen are grown as crops. The
cultivated species produce either a high leaf or a high grain yield. Three
species of the genus Amaranthus produce large seed heads loaded with
edible seeds: Amaranthus hypochondriacus and Amaranthus cruentus,
which are native to Mexico and Guatemala, are grown in the USA while
Amaranthus caudatus, which is native to Peru and other Andean countries,
does not grow well in the USA (Fig. 13.1). The main species found through-
out Mexico and into Guatemala and the south west of the USA are A.
hypochondriacus and A. cruentus. In South America (mainly A. caudatus)
they are found in a band stretching from southern Ecuador through Peru
and Bolivia into northern Argentina.

Amaranth grows very rapidly, particularly in conditions of bright sunlight
and high temperature and when it is sown in dry soil. The physiological
explanation for this attribute is that amaranth has the C4 type CO2 photo-
synthetic pathway. Plants of the C4 type are characterized by their more
effective photosynthesis, more intensive nitrogen metabolism and some
physiological peculiarities of their metabolic processes (Breus, 1997). They
also convert a higher ratio of atmospheric carbon into carbohydrate than
ordinary plants, in which photosynthesis follows the classic C3 (Calvin cycle)
pathway (Tucker, 1986). Amaranth is an annual broad-leafed plant. Variet-
ies vary from branched to unbranched, prostrate to erect, and dwarf to over
4 m in height. The leaves are normally elliptical, with an acute tip and a
cuneate base; leaf size varies significantly between and within species. The
flowers are indefinite inflorescences. The seed heads, some as long as 50 cm,
resemble those of sorghum and the seeds (Fig. 13.2) are extremely small,
barely bigger than mustard seeds (0.9–1.7 mm in diameter) and 30–70 times

Table 13.1 Botanical classification of amaranth

Classification Amaranth

Class Dicotyledoneae
Subclass Caryophyllidae
Order Caryphyllales
Family Amaranthaceae
Genus Amaranthus
Species At least 60 species, e.g.
A.caudatus
A.cruentus
A. hypocondriacus

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Amaranth 443

United States Colombia
Ecuador
Brazil
Peru

Mexico N Bolivia
Gulf of Chile
Mexico Pacific Ocean
Argentina

Pacific Ocean

N

Figure 13.1 The native habitats of grain amaranth. Darker areas indicate zones
where amaranth cultivation is concentrated.

Figure 13.2 Amaranth grains.
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444 Cereal grains for the food and beverage industries

smaller than a typical wheat grain. According to Saunders (1984), 1000
seeds weigh 0.5–1.2 g; alternatively, 1 g can contain 850–1700 seeds. They
occur in massive numbers, sometimes more than 50 000 to a plant, and vary
in colour from cream coloured, gold, pink, black, brown, yellow or white.

The seed embryo is campylotropous, i.e., circular, with its ends nearly
touching and enclosing the perisperm. This can be seen in Figs 13.3 and 13.4.
The embryo is therefore rather large and accounts for about 25 % of the
grain weight. The seed coat is completely smooth and thin. In contrast to
the other two pseudo-cereals, quinoa and buckwheat, it is not necessary to
remove the seed coat of amaranth. Hence the seed can be used directly in
most cases. The seed coat and embryo together constitute 26 % of the seed.
In Fig. 13.5 it is possible to see the structure of amaranth: the starchy peri-
sperm, part of the two cotyledons and the external seed coat. Nutrients are
concentrated in the seed-coat embryo fraction at higher levels than in the
original, intact seed: there is 2.3–2.6 times as much nitrogen, fat, fibre and
ash, 2.4–3.0 times as much thiamin, riboflavin and niacin and 1.4–2.5 times
as much of several mineral elements (Teutonico and Knorr, 1985; Taylor
and Parker, 2002; Bressani, 2003).

In general amaranth grain is characterized by relatively greater levels of
proteins and lipids and lower starch contents than the major cereals (maize,
rice and wheat). A comparison of the average chemical composition of
amaranth (A. hypochondriacus) and maize, rice and wheat is shown in Table
13.2. Analysis of the average chemical composition of the grains of several
amaranth species indicates that there are some variations among and within
species (Table 13.3). In the following sections, the chemical and nutritional
characteristics of amaranth grain are discussed.

13.2 Amaranth carbohydrate composition and properties

Starch is the major part of amaranth carbohydrates comprising about
48–69 % of its total dry weight. Starch granules are extremely small, ranging
from 0.8 to 2.5 µm in diameter and easily degradable by α-amylases.

13.2.1 Starch
Starch is the most abundant carbohydrate component of amaranth
(Saunders, 1984), and it is mainly stored in the perisperm (Fig. 13.6). Ama-
ranth starch comes in extremely small granules. With a diameter ranging
from 0.8 to 2.5 μm, they are the smallest ever recorded. For comparison,
the diameters of the granules in commercial starch range from 3 to 8 μm
for rice starch to 15 to 100 μm for potato starch. This is a potentially impor-
tant commercial advantage. The granules also have an almost crystalline
structure, an extremely unusual characteristic. Amaranth starch granules
are spherical or polygonal in shape (Saunders, 1984).

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Starchy perisperm

Cotyledons Procambium Cotyledons
Seed coat

© Woodhead Publishing Limited, 2013 Shoot apex

Root
Procambium

Perisperm Endosperm

Radicle
(root)

Cross section Longitudinal section

Figure 13.3 Illustration of A. cruentus seed in cross- and longitudinal sections.

446 Cereal grains for the food and beverage industries

C P
C

S ×430 50 μm AMRF, UCC
5 kV

Figure 13.4 Confocal scanning laser microscope (CSLM) micrograph (10 ×) of the
structure of amaranth showing the starchy perisperm (P), part of the two cotyledons

present (C) and the external seed coat (S).

P

S

200.0 μm
Figure 13.5 CSLM micrograph (10 ×) of the structure of amaranth showing the

starchy perisperm (P) and seed coat (S) enclosing the perisperm.

Amaranth starch granule size and size distribution are characteristics
that influence the functional properties of the crop. When suspended in
water, small single starch granules of 1–3 μm can be extracted from the
agglomerates (Choi et al., 2004). Most starch raw materials typically consist
of compound-starch particles made up of small granules. The particles
cluster together, reducing the surface area and forming characteristic
compounds. The specific surface area of starches increases remarkably as
the granule diameter decreases. Wilhelm et al. (2002) report a value of
5.194 m²/cm³ for the specific surface area of native amaranth granules

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Amaranth 447

Table 13.2 Comparison of the proximate composition of amaranth grains and
some cereals (% day weight basis)

Composition Amarantha Wheat Corn Rice

Carbohydrate 59.2 66.9 67.7 75.4
Crude protein 16.6b 14.0c 10.3d 8.5e
Fat 7.5 2.1
Crude fibre 4.1 2.1 4.5 0.9
Ash 3.3 2.6 2.3 1.4
Moisture 9.6 1.9 1.4 11.7
12.5 13.8

aMean values of flour Amaranthus species (A. cruentus, A.caudatus, A. hypochondriacus and

A. hybridus).
bN × 5.85. cN × 5.7. dN × 6.25.

Source: Cai et al., (2004).

Table 13.3 Proximate composition of amaranth grains from various species
(% day weight basis)

Component A. caudatus A. cruentus A. hybridus A. hypochondriacus

Carbohydrate 59.6–62.8 60.7–62.6 58.6 57.0
Crude proteina 17.6–18.4 13.2–18.2 14.0 17.9
Fat 6.3–8.1 6.7 7.7
Crude fibre 6.9–8.1 3.6–4.4 6.6 2.2
Ash 3.2–5.8 2.8–3.9 3.6 4.1
Moisture 3.1–4.4 10.5 11.1
9.5–11.6 6.2–8.8

aN × 5.85.
Source: Cai et al., (2004).

5 kV ×3,300 5 μm AMRF, UCC

Figure 13.6 CSLM micrograph (10 ×) of polygonal starch granules of amaranth
stored in the perisperm.

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448 Cereal grains for the food and beverage industries

starch using diffraction particle size distributions laser. The same authors
report a value of 0.833 and 0.976 m²/cm³ as the specific surface area of
native oats and wheat granule starches, respectively.

The starch content of amaranth is reported to range from 48 % for A.
cruentus to 69 % for A. hypochondriacus (Saunders, 1984). Comparison of
amaranth starch with cereal starch reveals two major differences between
this pseudo-cereal and the cereal grains. First, starch comprises the main
carbohydrate component of amaranth, but is usually found in lower amounts
than in cereals (see Table 13.2). Second, amaranth starch is not located in
the endosperm, but in the perisperm.

The amylose content of amaranth starch is much lower than that of other
cereal starches, with values varying from 0.1 to 11.1 % depending on differ-
ent genotypes (Qian and Kuhn, 1999; Choi et al., 2004). Amaranth amylo-
pectin was found to be composed of short-chain branched glucans with an
average molecular weight of 11.8 × 106 g mol−1 (Praznik et al., 1999). The
small size of the amaranth starch granule as well as its high amylopectin
content explains most of the physical properties of amaranth starch.

Compared to corn starch, amaranth starch shows excellent freeze–thaw
and retrogradation stability, higher gelatinization temperature (Wilhelm
et al., 2002; Choi et al., 2004) and viscosity (Becker et al., 1986), higher water-
binding capacity, lower solubility (Stone and Lorenz, 1984) and greater
water uptake at higher water activity values (Resio et al., 1999), as well as
higher swelling power and enzyme susceptibility (Stone and Lorenz, 1984;
Singhal and Kulkarni, 1990; Baker and Rayas-Duarte, 1998a; Choi et al.,
2004). By heating different starch suspensions at 55–95 °C, Choi et al. (2004)
showed that amaranth starch has a constant swelling power and shows no
increase in swelling power at temperatures higher than 75 °C. Additionally,
solubility did not change after 75 °C. Amaranth starch plays an important
role in food applications as a thickener in soups, as a fat replacer, in gravies
and sauces and in breakfast cereals, muffins, cookies, snacks, pastas and
health foods. Other current and potential commercial uses of amaranth
starch are in cosmetics, biodegradable films, paper coatings and laundry
starch (Choi et al., 2004).

13.2.2 Resistant starch
Resistant starch (RS) is not only naturally present in food but is also formed
during processing. Like dietary fibre, RS is not susceptible to human diges-
tive enzymes and thus reaches the colon, where it is fermented by the bacte-
rial biota. RS has beneficial physiological effects like lowering blood lipids
or lowering the risk for colon cancer. The RS content of a food depends on
the characteristics of the starch present (type of granule, amylose/amylo-
pectin ratio and crystallinity of starch), as well as on the analytical method
used and the food processing conditions employed. Capriles et al. (2008)
found a RS content of 0.05 % in the raw seeds. The RS content is increased

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Amaranth 449

by the roasting process. This may be due to the fact that amaranth starch
presented about 1 % of amylose (Capriles et al., 2008) and, possibly after
cooling down, retrogradation of amylose chains occurs, increasing RS con-
tents in roasted seeds. In contrast, the cooking process generally decreases
RS contents (Capriles et al., 2008), mainly due to the starch gelatinization
(Lara and Ruales, 2002; Gamel et al., 2006; Mikulikova and Kraic, 2006).
Finally, no significant differences were found among RS contents of raw,
popped and extruded amaranth seeds. These dry heat processes were most
likely unable to gelatinize RS in amaranth seeds. Similar results were also
reported by Guerra-Matias and Arêas (2005) and González et al. (2007).
Cummings and Englyst (1995) determined the RS content in popped ama-
ranth, which was approximately 0.5 %, showing the high digestibility of the
amaranth starch.

The RS/total starch proportion in raw amaranth seeds was 0.86 %
(Capriles et al., 2008). Crops containing more than 4.5 % RS are consid-
ered to be a good source (Capriles et al., 2008); therefore, amaranth does
not fall into this category and grain amaranth alone cannot be suggested
for use in diabetic diets. However, amaranth flour can be used to partially
substitute wheat flour or other cereals and can make the preparation/diet
more nutritious in terms amino acid pattern and minerals (Chaturvedi
et al., 1997).

13.2.3 Low molecular weight carbohydrates
Mono- and disaccharides can only be found in small amounts (3–5 %) in
amaranth. According to Gamel et al. (2006), the total sugar content of the
two species A. cruentus and A. caudatus ranges from 1.84 to 2.17 g/100 g.
Sucrose was found to be the dominant sugar with values of 0.58–0.75 g/100 g.
The values of the other sugars were: galactose plus glucose 0.34–0.42 g
/100 g, fructose 0.12–0.17 g/100 g, maltose 0.24–0.28 g/100 g, raffinose 0.39–
0.48 g/100 g, stachyose 0.15–0.13 g/100 g, inositol 0.02–0.04 g/100 g. The
values were in good agreement with previously reported data (Becker
et al., 1981; Saunders, 1984).

13.2.4 Dietary fibre
Dietary fibres, both soluble and insoluble, are known to have beneficial
effects on human health. The dietary fibre content of amaranth lies within
the range of other cereals and shows great variation within different species.
Total dietary fibre content (soluble and insoluble) in amaranth grains from
A. caudatus, A. cruentus and A. hypochondriacus range between 9.8 and
14.5 % (Mustafa et al., 2011; Tosi et al., 2001). Generally, the crude fibre
content of amaranth grain (3.6–4.2 %) (Ayo, 2001) is much higher than
the fibre content of wheat (2.6 %), maize (2.3 %) and rice (0.9 %) (Cai
et al., 2004).

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450 Cereal grains for the food and beverage industries

13.3 Other constituents of amaranth

The second most abundant component of amaranth grains is protein, fol-
lowed by lipids and minerals.The lipids content is generally more than twice
that of wheat and amaranth lipids are characterized by high proportion of
unsaturated fatty acids.

13.3.1 Protein
Amaranth contains 16–18 % protein, compared with values of 14 % or less
in wheat and other cereals (Table 13.2). The nutritional value of pseudo-
cereals is mainly due to their protein content and amaranth has higher
protein content than buckwheat or quinoa. Sixty-five percent of the pro-
teins are located in the germ and seed coat and 35 % in the starch-rich
endosperm (Pszczola, 1998).

In contrast to most common grains, the proteins in amaranth are com-
posed mainly of globulins and albumins, and contain very little or no
storage prolamin proteins (major components of the gluten protein frac-
tion) (Saunders, 1984), which are the main storage proteins in cereals, and
also the toxic proteins in coeliac disease (CD). Gluten’s unique properties
in bakery products are due to its ability to form thin gas-retaining films, its
ability to aggregate into stretchable, extensible, coaguable, protein–starch
matrix (Shewry and Halford, 2002). Its presence determines the overall
appearance and textural properties of cereal-based products. Amaranth
seed protein is especially noteworthy due to its excellent balance of essen-
tial amino acids that the human body cannot manufacture. In particular,
it contains an unusually high percentage of the amino acid lysine (three
times higher compared to wheat flour) (Table 13.4), which is present only
at low levels in wheat, corn and rice. Bressani et al. (1993) considered threo-
nine, rather than leucine, to be the first limiting amino acid in amaranth
protein, while other authors (Pedersen et al., 1986; Bejosano and Corke,
1998) state that leucine is the first limiting amino acid, followed by valine
or threonine.

Amaranth protein composition is near to the ideal protein according to
FAO requirements for adults. Amaranth also scores higher than other seeds
(e.g., wheat, barley, soybean and maize) (Table 13.5) in the FAO/WHO
Nutritionist’s Protein Value Chart. A score of 100 is the ideal (i.e. perfect
balance of essential amino acid on the nutritionist’s scale of protein quality
based on amino acid composition); amaranth protein received the highest
score of 75 (resulting primarily from the high content of lysine), compared
to cow’s milk (score 72), soybeans (68) and peanuts (52), indicating that its
balance was closer to the optimum required in the human diet (FAO/WHO/
UNU, 1986). When amaranth flour is mixed with corn flour for making
bread or tortillas, the combination almost reaches the perfect 100 score,
because the amino acids that are deficient in one are abundant in the other.

© Woodhead Publishing Limited, 2013

Table 13.4 Essential amino acids in amaranth and other pseudocereals and the recommended requirements for adult humans

© Woodhead Publishing Limited, 2013 Amino acid Amaranth Quinoa Buckwheat Corn Rice Wheat FAO/WHO/UNU
(g/100 g protein) adult recommendationa
2.6 3.2 2.7 2.6 2.1 2.0
Histidine (His) 3.7 4.9 3.8 4.0 4.1 4.2 Adult
Isoleucine (Ile) 5.4 6.6 6.4 12.5 8.2 6.8
Leucine (Leu) 5.3 6.0 6.1 2.9 3.8 2.6 1.5
Lysine (Lys) 2.3 5.3 2.5 4.0 3.6 3.7 3.0
Methionine (Met) 3.6 6.9 4.8 8.6 10.5 8.2 5.9
Phenylalanine (Phe) 3.5 3.7 3.9 3.8 3.8 2.8 4.5
Threonine (Thr) – 0.9 2 0.7 1.1 1.2 16
Tryptophan (Try) 4.3 4.5 5.1 5.0 6.1 4.4 –
Valine (Val) 2.3
0.6
3.9

aScoring pattern for an ideal protein as reported by FAO WHO/UNU (2007).
Sources: Data from National Research Council (1984), Pomeranz and Robbins (1972), Valencia-Chamorro (2004), Cai et al. (2004).

452 Cereal grains for the food and beverage industries

Table 13.5 Food values of different vegetable
proteins

Foods Food value of protein in marks

Amaranth 75–78
Corn 44
Wheat 57
Sorghum 47
Barley 62
Pulse 67
Peanut 25
Soya 68
Kidney bean 55
Walnut 45
Cow milk 72

The result is an almost ‘perfect’ protein, comparable in nutritional quality
to eggs, that meets virtually all the body’s requirements. The protein content
and amino acid pattern of amaranth depend on genotype and growing
conditions.

Storage proteins
Seed proteins are generally classified into four types based on solubility:
albumin, globulin, prolamin and glutelin. Most studies on amaranth proteins
suggest that albumin is the major fraction (about 40 %), followed by glutelin
(25–30 %), globulin (20 %) and prolamin (2–3 %) (Segura-Nieto et al., 1994;
Bucaro Sequra and Bressani, 2002). There was variation between the results
obtained by these studies because of protein extraction and fractionation
procedures and genetic variation. For instance, Gorinstein et al. (2004)
found a lower amount of prolamin-like (alcohol-soluble) proteins of about
1.2–1.4 %, and even lower levels of prolamins (0.48–0.79 %) were measured
by Muchova et al. (2000). According to Gorinstein et al. (2004) the propor-
tions of proteins in amaranth are similar to those found in rice. By using
scanning electron microscopy (SEM) and SDS-PAGE, the same authors
found a close similarity between the protein fractions of amaranth
and those of soybean. The prolamin fraction was different to that found
in cereals, whereas the glutelin fraction was similar to that of maize
(Gorinstein et al., 2004). According to their sedimentation coefficient, two
main classes of globulins can be differentiated in the legume seed: 7S and
11S globulins. In amaranth, similar 7S (conamaranthin) and 11S (amaran-
thin) storage globulins have been found (Marcone and Kakuda, 1999).
Thermal treatment decreased the water-soluble protein fraction (albumins
and globulins) and alcohol-soluble fraction (prolamins) of amaranth (Gamel
et al., 2005). It can be concluded that the amaranth proteins are similar to

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Amaranth 453

seed proteins in other dicotyledonous crops like legumes, and have no
relationship to the major prolamins of cereals.

Protein quality depends not only on the amino acid composition, but also
on protein bioavailability or digestibility. Protein digestibility, available
lysine, net protein utilization (NPU), protein efficiency ratio (PER) or bio-
logical value (BV) (Schaafsma, 2000) are widely used as indicators for the
nutritional quality of proteins. In this respect, amaranth protein quality is
very high and it has a performance comparable to the cheese when ama-
ranth is studied in humans (Bressani et al., 1993). Bejosano and Corke
(1998) measured an average protein digestibility of 74.2 % for raw ama-
ranth wholemeal flours. Slightly higher values were determined by Gamel
et al. (2004) of 81 and 80–86 %. An increase in protein digestibility was
observed by popping and roasting of amaranth grain at 170–190 ºC, either
at normal or increased pressure (Pisarikova et al., 2005). During popping,
trypsin inhibitors and other antinutritional factors are inactivated (Correa
et al., 1986; Fadel et al., 1996). However, the popping process can also reduce
the nutritional quality of amaranth seed protein. Indeed, during the popping
process, the heat treatment caused a loss of several essential amino acids,
especially tyrosine, phenylalanine, methionine and lysine, which is the
reason for the reduction in protein quality (Gamel et al., 2004).

Allergy and coeliac disease
To date, only a few studies have been performed on amaranth allergy or on
the toxicity of amaranth proteins in CD. Studies of allergenic reactions to
the prolamin fraction of amaranth were undertaken by Matuz et al. (2000)
and Bossert and Wahl (2000). In contrast to wheat, barley, rye, triticale and
oats, the prolamin fraction of amaranth showed no reactivity against the
rabbit antigliadin (wheat) antibodies. In vivo and in vitro investigations of
general allergic reactions to amaranth revealed that amaranth causes a
classical type 1 reaction in sensitized patients (Bossert and Wahl, 2000). On
the other hand, Hibi et al. (2003) found that amaranth grain and its extract
inhibited antigen-specific IgE production by augmenting Th1 cytokine
responses in vivo and in vitro. Genetically modified maize with an amaranth
11S globulin (amarantin) caused no important allergenic reactions to ama-
rantin during in vitro investigations (Sinagawa-Garcia et al., 2004). In con-
clusion, results collected so far indicate that amaranth is not toxic to coeliac
patients.

Functional properties of proteins
In the past two decades, many researchers (Segura-Nieto et al., 1994;
Bejosano and Corke, 1999; Fidantsi and Doxastakis, 2001; Kovacs et al.,
2001; Salcedo-Chavez et al., 2002) have isolated major fractions (albumin,
globulin and glutelin) of proteins from main Amaranthus species and exam-
ined their biochemical and functional properties. Based on their measure-
ments of its emulsifying properties, foaming capacity and stability, and fat

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454 Cereal grains for the food and beverage industries

absorption capacity, along with its relatively high heat stability, it was con-
cluded that amaranth globulin isolate possesses highly desirable attributes,
particularly in the vicinity of its isoelectric point (protein and thermal solu-
bility) as compared to the corresponding soybean globulin. Amaranth glob-
ulin also exhibited better emulsification and foaming properties over a
broad pH range from 3 to 9 than the soybean globulin (Bejosano and Corke,
1999; Marcone and Kakuda, 1999). On the other hand, Tomoskozi et al.
(2008) reported that protein fractions of amaranth seed have relatively
poor emulsifying and foaming properties when compared with casein and
soy protein isolates. The different results may partly be explained by the
modes of preparation of proteins and the methods used. Despite the results
of Tomoskozi et al. (2008), the utilization of amaranth proteins as food addi-
tives and ingredients is feasible and could be of use to the food industry.
Essentially, for this to be viable, procedures for the extraction of amaranth
protein need to be optimized and the protein structure needs to be modi-
fied. Some preliminary investigations of enzymatically or/and chemically
modified amaranth protein suggest that it is possible to improve its func-
tional properties (Tomoskozi et al., 2008).

Enzyme inhibitors
Many food plants contain one or more protease inhibitors (e.g. α-amylase,
chymotrypsin or trypsin inhibitors) that competitively inhibit the activity
of proteolytic and amylolytic enzymes. Protease inhibitors can be anticar-
cinogenic, antioxidative, blood pressure and glucose regulatory, as well as
anti-inflammatory. However, heat treatment can reduce their activity.
Compared to other cereals, amaranth contains only very low amounts of
protease inhibitors, less than conventional cereals. Gamel et al. (2006) found
trypsin inhibitor activity (TIU) ranging from 3.05 to 4.34 TIU/mg, chymo-
trypsin inhibitor activity (CIU) ranging from 0.21 to 0.26 CIU/mg and
amylase inhibitor activity ranging from 0.23 to 0.27 AIU/mg. Trypsin,
amylase and, in particular, the chymotrypsin inhibitors decrease after heat
treatment or germination.

13.3.2 Lipids
The fat content of amaranth is about two to three times higher than that
of other cereals (Table 13.6) and varies again greatly between the species.
Amaranth oil contains more than 75 % unsaturated fatty acids and is par-
ticularly rich in linoleic acid, oleic acid and palmitic acid. Also present at
lower levels are stearic and linolenic acids at 3.9 % and 0.7 %, respectively,
with a high degree of unsaturation (Table 13.6). Other lipids have also been
identified in amaranth, including triglycerides, sterols, phospholipids, glyco-
lipids, tocopherols and hydrocarbons (Corke et al., 2002; Gamel et al., 2007).

The fatty acid profile of amaranth oil was also very similar to those of
cereal oils, with some similarity to cottonseed and sesame oils where C18:1

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Amaranth 455

Table 13.6 Fatty acid composition of amaranth and wheat

Component (%) Amaranth Wheat

Lauric acid (C12:0) 0.7 –
Myristic acid (C14:0) 0.2 –
Palmitic acid (C16:0) 20.4 24.5
Palmitoleic acid (C16:1) 0.4 –
Margaric acid (C17:0) 0.1 –
Heptadecenoic acid (C17:1) 0.7 –
Stearic acid (C18:0) 3.9 1.0
Oleic acid (C18:1) 33.3 11.5
Linoleic acid (C18:2) 38.2 56.3
Linolenic acid (C18:3) 0.7 3.7
Arachidic acid (C20:0) 0.8 –
Gadoleic acid (C20:1) 0.3 0.26
Behenic acid (C22:0) 0.3 –
Others – 3.0

Soruces: Data from Leon-Camacho et al., (2001), Chung et al. (2009), Oelke, (1997), He et al.,
(2002).

and C18:2 are the major fatty acids, with percentage contents of 36.1 and
61.3 %, respectively (Aparicio et al., 2001). Amaranth also contains signifi-
cant amounts of squalene, a lipid which is more commonly extracted from
the livers of deep-sea dogfish (sharks of the Squaliformes order). The
squalene content of amaranth ranges from 2.4 to 8 % of the extractable oil
(ca 0.3–0.4 % of the total seed mass). Squalene is a highly unsaturated open-
chain triterpene and is a biochemical precursor of cholesterol and other
steroids It is used as skin-care products in the cosmetic industry, as drug
carrier in pharmaceutical formulations (Gamel et al., 2007) and as high-
grade machine oil. In addition, squalene acts as a protective and preventive
agent in cancer treatment, decreasing the chemotherapy-induced side-
effects (Reddy and Couvreur, 2009). In more detail, squalene has been
found to be active against colon cancer (Rao et al., 1998), and to have a
hypocholesterolaemic effect (Miettinen and Vanhanen, 1994; Shin et al.,
2004). Since it is well absorbed orally, it has been used to improve the oral
delivery of therapeutic molecules (Reddy and Couvreur, 2009) and can also
act as a sink for xenobiotics, as it can dissolve most hydrophobic compounds
(Richter et al., 1982). It is an important ingredient in skin cosmetics, due
to its photoprotective role, and acts as a lubricant for computer disks,
due to its thermostability (Budin et al., 1996). Shin et al. (2004) found that
amaranth squalene has cholesterol-lowering effect by increasing faecal
elimination of steroids through interference with cholesterol absorption.
The effect was higher than that of shark-liver squalene. In addition, ama-
ranth oil and amaranth grain lowered serum and hepatic cholesterol as well

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456 Cereal grains for the food and beverage industries

as triglycerides, confirming previous findings (Budin et al., 1996; Gamel
et al., 2004). Amaranth oil will attract more attention as an alternative
plant source of squalene because of its abundant squalene content. It can
easily be extracted from amaranth grain by simple vacuum distillation (Cai
et al., 2004).

Phospholipids constitute about 5 % of the oil fraction of amaranth
(Becker et al., 1981). In a previous study, Opute (1979) measured 3.6 %
phospholipids in amaranth oil, of which the cephalin fraction was 13.3 %,
the lecithin 16.3 % and the fraction of phosphoinositol 8.2 %. Total sterols
in amaranth oil are 24.6 × 10³ ppm (Aparicio et al., 2001) and almost all
sterols of amaranth oil are esterified. In most vegetable oils, the percentage
of free (non-esterified) sterols is usually much higher. The major sterol
present is clerosterol (42 %), which has antibacterial activity. The high con-
centration of sterols makes amaranth oil potentially useful in pharmaco-
logical applications (Aparicio et al., 2001).

13.3.3 Minerals
The mineral (ash) content of amaranth is about twice as high as that of
other cereals (Table 13.7). It varies among varieties and is also affected by
processing. The Levels of Ca, Mg, Fe, K and Zn are particularly high (Yanez
et al., 1994; Bressani, 2003; Gamel et al., 2006) (Table 13.7).

Sanz-Penella et al. (2012) supplemented wheat bread with whole ama-
ranth flour (0, 20 and 40 %) with the aim to evaluate the effect of phytates
on in vitro iron absorption. Whole amaranth flour has shown to limit avail-
able Fe depending on the percentage used in bread formulation. However,
the inclusion of whole amaranth flour up to 20 % in bread formulation
appears as a promising strategy to increase the nutritional value of bread,
since it constitutes a useful vehicle to increase the concentration of avail-
able Fe in breads.

Table 13.7 Content of certain minerals in amaranth, quinoa, buckwheat and
wheat seeds

Mineral Amaranth Quinoa Buckwheat Wheat

Calcium 159.1 ± 26.10 47 ± 0.33 18 ± 0.00 34 ± 1.53
Magnesium 248.2 ± 23.48 197 ± 6.66 231.4 ± 8.8 144 ± 3.7
Zinc 3.10 ± 0.10 1.2 ± 0.10
Potassium 2.87 ± 0.12 563 ± 38.44 2.40 ± 0.0 431 ± 10.20
Phosphorus 508 ± 17.04 457 ± 23.33 460 ± 0.00 508 ± 20.74
Iron 557 ± 46.16 4.57 ± 0.16 347 ± 0.00 3.52 ± 0.10
7.61 ± 0.83 2.20 ± 0.10

Note: Data presented as mg/100 g day weight basis ± standard deviation.
Source: USDA/ARS (2012).

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Amaranth 457

13.3.4 Vitamins
Overall, amaranth does not constitute an important source of vitamins. As
reported in Table 13.8, however, amaranth is a good source of riboflavin,
vitamin C and in particular of folic acid and vitamin E (Gamel et al., 2006).
Folic acid has been found at a level of 82 μg/100 g, twice that of wheat
(43 μg/100 g) (Table 13.8). Vitamin E, present in amaranth the form of
tocopherols and possibly also tocotrienols, possesses antioxidative effects,
thus increasing the stability of amaranth oil. Bruni et al. (2002), using super-
critical fluid extraction, found total tocopherol levels of 100–129 mg/kg in
amaranth seeds. α-tocopherol, which has high antioxidant activity, was the
most abundant of the tocopherols extracted. Tocotrienols, another member
of the vitamin E family, are important compounds with hypocholesterolae-
mic activity. Contradictory results have been reported about their presence
in amaranth. According to Lehmann et al. (1994) amaranth grains have
significant amounts of β-tocotrienols (5.02–11.47 mg/kg seed) and γ-
tocotrienols (0.95–8.69 mg/kg seed), whereas Budin et al. (1996) and
Aparicio et al. (2001) did not detect any tocotrienols in amaranth. In con-
trast to primary metabolites such as starch, fat or proteins, phytochemicals
are only found in small amounts in plants. Phytochemicals are known to
have pharmacological effects and have always been part of the human diet.
In the past, both plant breeders and food technologists aimed to remove
these substances from plants, since they were perceived to be negative for
human nutrition (i.e they were considered antinutrients). However, recent

Table 13.8 Vitamin content of amaranth

Vitamins Amaranth Quinoa Buckwheat Wheat

Vitamin C (total ascorbic 4.20 ± 0.00 n.r n.r n.r
acid)a
0.11 ± 0.09 0.36 ± 0.01 0.10 ± 0.00 0.42 ± 0.01
Thiamina 0.20 ± 0.04 0.32 ± 0.01 0.42 ± 0.00 0.12 ± 0.00
1.46 ± 0.10 0.77 ± 0.04 1,23 ± 0.00 0.95 ± 0.00
Riboflavina 0.59 ± 0.04 0.49 ± 0.04 0.21 ± 0.00 0.42 ± 0.02
184 ± 8.37
Pantothenic acida 82 ± 14.38 30 ± 0.00 43 ± 0.00
2 14 0 0
Vitamin B6a 2.44 ± 0.19 n.r. n.r.
Folate (total)b 1.19 ± 0.42 0.08 ± 0.01 n.r. n.r.
0.96 ± 0.48 4.55 ± 0.66 n.r. n.r.
Vitamin Ac 0.19 ± 0.35 0.35 ± 0.07 n.r. n.r.
0.69 ± 0.35
Vitamin E – α-tocopherola
β-tocopherola
γ-tocopheroa
δ-tocopherola

amg 100 g−1. bμg 100 g−1. cinternational units.
n.r.= not reported.
Source: USDA/ARS (2012).

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458 Cereal grains for the food and beverage industries

research has shown that phytochemicals can also fulfil important functions
in the human body.

Phenolic compounds are the major source of natural antioxidants in
plant food. It has been reported that amaranth seed flour contains polyphe-
nols (flavonoids) with relatively high antioxidant status. In the research
work published by de la Rosa et al. (2009), three polyphenols, rutin, nicoti-
florin and isoquercitin, isolated from different amaranth varieties were
identified and quantified. Rutin was present at the highest concentration
(10.1–4.0 μg g−1) followed by nicotiflorin (7.2–4.8 μg g−1) and isoquercitrin
(0.3–0.5 μg g−1). These polyphenols are promptly degraded at the intestine
levels due to the presence of β-glucosidase enzyme able to liberate the
aglyconic moiety of the molecules. Several health effects have been related
to the uptake of the aglyconic groups, quercetin and kaempferol (Donovan
et al., 2007).

Rutin and its metabolites are compounds that could have implication in
the prevention of several pathologies by inhibiting the formation of the
glycation end-products (AGE) (Pashikanti et al., 2010), complex, heteroge-
neous molecules which are correlated with processes resulting in ageing and
diabetes complications (Cervantes-Laurean et al., 2006). Polyphenols such
as quercetin have been shown to act as a protective defence against oxida-
tive damage in vivo (Meyers et al., 2008). Nicotiflorin has been claimed to
have protective effects on reducing memory dysfunction (Huang et al.,
2007); recent results have proved a strong pharmacological basis for its
potential therapeutic role in cerebral ischaemic illness (Li et al., 2006).

Saponins are present in many plant species, including spinach, asparagus
and soybeans. Chemically, they are glucosides that, upon hydrolysis, liberate
one or more sugar units and free aglycon sugar, or sapogenins. These latter
can have a steroid or triterpenoid structure. Strongly bitter tasting, saponins
are surface active agents (surfactants), which can cause intensive foaming
activity in aqueous solutions. They can form complexes with proteins and
lipids, e.g. cholesterol, and possess a haemolytic effect. Saponins are only
absorbed in small amounts, and their main effect is restricted to the intes-
tinal tract. Saponins can form complexes with zinc and iron, thus limiting
the bioavailability of these minerals (Chauhan et al., 1992). Amaranth seeds
contain rather low levels of saponins ranging between 0.09−0.1 % of dry
matter. Oleszek et al. (1999) investigated whether soaking and germination
processes changed the saponin content of amaranth. They found that an
increase in their concentration was registered after 96 h of germination
(Table 13.9) although the levels reached were still relatively low. The low
concentration of saponins in amaranth seeds and their relatively low toxic-
ity indicate that the presence of these compounds does not create any
hazard for consumer health. From a saponin point of view, amaranth-
derived products can be recognized as safe (Oleszek et al., 1999).

Phytate, myo-inositol hexakisphosphate or IP6, is a naturally-occurring
compound found in all seeds and possibly all cells of plants. In its native

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Amaranth 459

Table 13.9 Concentration of saponins in germinating amaranth seeds

Germination time (h) Conc. (mg/g) Germination time (h) Conc. (mg/g)

24 0.79 ± 0.08 168 1.69 ± 0.12
48 0.94 ± 0.07 192 0.85 ± 0.07
69 1.86 ± 0.16 216 0.92 ± 0.08
120 1.78 ± 0.14 240 0.95 ± 0.07
144 1.39 ± 0.14

Source: Oleszek et al. (1999).

Table 13.10 Phytic acid content of A. caudatus and A. cruentus during
germination

Sample/germination Phytic acid Sample/germination Phytic acid (%)
time (h) (%) time (h)

Dry weight basis 0.44 ± 0.03 Dry weight basis 0.32 ± 0.02
A. caudatus 0.31 ± 0.02 A. cruentus 0.24 ± 0.01
0 0.20 ± 0.03 0.04 ± 0.01
24 0.14 ± 0.01 0
48 24 nd
72 48
72

Note: Values are mean ± standard deviation.
nd = not detectable.
Source: Adapted from Deruiz and Bressani (1990).

state it complexes with proteins as well as mono- and divalent cations.
Cereals and legumes are particularly rich in phytic acid, which represents
a major reserve of phosphate. Amaranth contains phytates in the range
0.2–0.6 % (Breene, 1991; Escudero et al., 2004; Gamel et al., 2006). Phytic
acids can form complexes with the basic protein residues, leading to the
inhibition of enzymatic digestive reactions and interference with the adsorp-
tion of minerals, in particular with zinc. Therefore, efforts are made to
reduce their levels in grains. Recently, it has been shown that cooking
reduces the phytate content of amaranth by approximately 20 %, popping
by 15 % and germination (48 h) by 22 % (Gamel et al., 2006). The phytic
acid content of two species of amaranth at different germination times is
shown in Table 13.10. Because germination is mainly a catabolic process
that supplies important nutrients to the growing plant through hydrolysis
of reserve nutrients, and phytic acid is a source of phosphorus and cations
during germination, this method is expected to produce a remarkable
reduction in phytic acid.

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460 Cereal grains for the food and beverage industries

13.4 Amaranth processing and applications in foods
and beverages

A variety of traditional foods are made from amaranth grains in many
countries, e.g. ‘alegria’ and ‘atole’ in Mexico, ‘alboroto’ in Guatemala, ‘bolos’
in Peru, ‘Chapati’ in the Himalayas, ‘laddoos’ in India and ‘sattoo’ in Nepal.
These amaranth-based foods are still consumed today in various areas of
the world. Alegria (‘joy’), for example, a mixture of popped amaranth grains
and syrup, is consumed in high amounts by Mexicans, as a very tasty and
nutritional snack. Seeds of some species of grain amaranth are traditionally
popped to make a variety of snack products, milled to make flour for use
in baked products and also used to make pasta (Kuhn and Goetz, 1999;
Kovacs et al., 2001). Amaranth grains are also used to make breakfast foods,
infant/weaning food formulations and beverages. A comprehensive over-
view of amaranth-containing foods can be found in Table 13.11.

13.4.1 Popping
The popping capacity of amaranth grain was discovered in the capital of
the Aztec empire thousands of years ago (Tovar et al., 1994). Popping
(puffing) is one of the most popular and oldest ways to process amaranth.
Moreover, it represents an interesting technology for processing amaranth
seeds, because of the ease of processing and the enjoyable flavour of the

Table 13.11 Possible uses of amaranth seeds in food products

Soup (grain and flour)
Pilaf (grain)
Pasta, noodles (flour)
Infant/weaning food formulations (grain and flour)
Pancakes (flour, whole grain, and popped grain)
Breakfast cereals (whole, popped, or sprouted-grain flour)
Porridge (popped grain in milk)
Breads, rolls, muffins and many other forms of baked foods (flour, popped grain,

toasted grain, whole grain)
Crepes (flour, popped grain)
Dumplings, tostadas, tortillas, fritos and corn pones (flour, whole or popped grain)
Cookies and crackers (flour, whole or popped grain)
Snack bars (popped grain, toasted grain or sprouted grain)
Toppings (popped grains, flour)
Beverages (flour, popped grain)
Fillers (whole or popped grain, flour or starch)
Confections (popped grain)

Source: National Research Council (1984).

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Amaranth 461

end-product (Bressani et al., 1992) generally characterized as corn-like,
nutty, hazelnutty and having roasty odours (Gamel and Linssen, 2008).

In popping, the heat causes vaporization of the water contained in the
starch matrix increasing the temperature and pressure and the successive
swelling and expansion of starch granules. The endosperm is transformed
into a bubbly matrix, which solidifies through the evaporation of water,
yielding a spongy structure and good crunch and taste qualities (Lara and
Ruales, 2002). The expansion volume of the amaranth seed after popping
is a crucial factor affecting the texture of the final products; a high expan-
sion volume improves texture and edibility and, thus, the quality of the food
product (Tovar et al., 1994). In this regard, Lara and Ruales (2002) showed
that the treatments of amaranth seed with high popping capacity produced
grains with high crunch and expansion capacities.

A traditional confection of popped amaranth seeds with molasses or
syrup is known as alegria in Mexico or ladoos in India (Konishi et al., 2004).
In the latter, popped amaranth seeds are mixed with milk and/or honey in
order to make confections. It can also be used as breakfast cereal (Guenault,
1985).

13.4.2 Milling
Amaranth seed can be milled to produce flour using conventional wheat
milling technology. However, due to the botanical peculiarities of the ama-
ranth seed – the fact that the embryo enclosing the starch-rich perisperm
in the form of the ring and its extraordinarily small size – if separation by
milling into fractions of different chemical composition is required, conven-
tional milling technology cannot be used in the traditional way; instead, it
must be adapted. Using a proper grinding and separation system, it is pos-
sible to fractionate amaranth into flours with different physical properties
and chemical compositions. Betschart et al. (1981) used a modified Strong-
Scott barley pearler to separate amaranth into seed coat (hull)-germ and
perisperm fractions. Within five passes through the pearler, the seed coat
and germ were completely separated; a spherical, intact starch-rich peri-
sperm was left. Another successful separation of the germ and the bran
from the perisperm was obtained by Becker et al. (1986) using a modified
stone mill. By leaving a 0.17–0.28 mm milling gap between the millstones,
the embryo and increasing amounts of bran were milled off (about 90 % of
the seed weight). The same stone mill can be used commercially with
smaller gap settings to produce whole kernel flour. Seed moisture content
had a significant effect on the milling characteristics, and moisture at
≤ 13.8 % gave good separation of the bran and kernel (perisperm). Increas-
ing moisture to 17.8 % gave similar milling results but caused the flour to
overheat and stick to the mill faces and mill chamber. The perisperm frac-
tion can be milled for flour or used as a starting material for the isolation
of starch granules.

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462 Cereal grains for the food and beverage industries

13.4.3 Baked products
Amaranth flour is especially suitable for the production of unleavened (flat)
breads like tortillas and chapatis where it can be used as the sole or major
cereal ingredient. For baking yeast-raised breads or other leavened goods,
amaranth flours must be blended with wheat flour because on their own
they cannot retain gas as they do not contain gluten. Lorenz (1981) found
that up to 10–15 % of the wheat flour in a formulation could be replaced
by amaranth flour with little detrimental effect on bread quality. A 10 %
replacement lowered loaf volume by 7–10 % and resulted in darker coloured
bread; however, a taste panel preferred the ‘nutty’ flavour of these breads
over those made using only wheat flour. Bruemmerm and Morgentren
(1992) also reported that amaranth can be used, in amounts of 20–25 %, to
obtain acceptable products only when amaranth grain was cooked after
dehulling. A higher level of addition results in large decreases in volume, a
decline in crumb structure and less acceptable sensory properties: the
higher the level of addition, the darker the crumb and the stronger the taste
(Bruemmerm and Morgentren, 1992; Kuhn and Goetz, 1999). Bodroza-
Solarov et al. (2008) reported that supplementation of popped amaranth
(A. cruentus) in ranges from 10–20 % (flour basis) into wheat bread formu-
lations significantly increased the zinc content (from 42.6 to 74.6 %), man-
ganese content (from 51.7 to 90.8 %), magnesium content (from 75.7 to
88.0 %) and calcium content (from 57 to 171 %). Moreover, the squalene
content was increased 8–12 times in comparison with the control sample.
At the same time, loaf volume decreased (from 3.54 to 2.36 ml/g), crumb
hardness decreased and low crumb elasticity was observed. On the basis of
these results, Bodroza-Solarov and colleagues (2008) concluded that sup-
plementation levels up to 15 % (flour basis) were sensorially acceptable.

In contrast, Rosell et al. (2009) showed that the replacement of wheat
flour with 50 % A. caudatus flour still produced breads with good sensory
acceptability albeit dark in colour, acceptable thermomechanical patterns
and acceptable technological properties. Even greater levels of amaranth
addition into wheat bread formulations were reported by de la Barca et al.
(2010), who showed how the addition of 60–70 % popped amaranth flour
and 20–40 % raw amaranth flour into the bread recipe produced loaves with
homogeneous crumbs and higher specific volumes (3.5 ml/g) than other
gluten-free breads. Generally, the addition of amaranth flour to a bread
recipe increases water binding and therefore increases moisture-holding
capacity and shelf-life, but decreases mixing time, mixing tolerance, dough
stability, gelatinization temperature, viscosity and bread volume, in spite of
an increased proof time.

Sourdough fermentation shows promise to improve the baking perfor-
mance of amaranth-enriched baked wheat goods. Houben et al. (2010)
showed that sourdough fermentation is able to produce a dough with
similar viscosity and elasticity to that of a pure wheat flour dough. More-
over, Jekle et al. (2010) found that bread produced by adding 20 %

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Amaranth 463

amaranth sourdough fermented with Lactobacillus heleveticus received the
highest score in a sensory test. This finding may be due to the high proteo-
lytic activity of L. helveticus, a bacteria which can release a high level of
amino acids known to act as precursors for many important bread aroma
compounds (Czerny et al., 2005).

Recently, de la Barca et al. (2010a) evaluated the mixing properties and
bread- and cookie-making quality of flour from raw and popped amaranth
looking for the best combinations. The best formulation for bread included
60–70 % popped amaranth flour and 30–40 % raw amaranth flour which
produced loaves with homogeneous crumb and higher specific volume
(3.5 g/ml), while the best cookies recipe had 20 % of popped amaranth flour
and 13 % of whole-grain popped amaranth.

13.4.4 Pasta
‘Tagliatelle’ pasta products made from wheat and amaranth were developed
by Wesche-Ebeling et al. (1996). Different formulations were investigated
for their sensory properties, cooking time, cooking loss and water absorp-
tion.The formulations differed considerably in cooking loss but only slightly
in terms of cooking time and water absorption. From the sensory point of
view, products containing amaranth at levels higher than 14 % were increas-
ingly rejected. The product that obtained the best level of acceptance was
formulated as follows: 85.2 % wheat flour, 4.1 % dry egg and 10.7 % ama-
ranth flour, with or without colouring (spinach or beet). Similar result were
obtained in the study conducted by Sun et al. (1995). Again, with increasing
addition of amaranth, buckwheat and lupin flour, cooking loss increased.
Finally, the taste of pastas containing amaranth added at levels of 25–30 %
and higher was described as musty.

Schoenlechner et al. (2010) investigate the production of gluten-free
pasta from 100 % amaranth, quinoa and buckwheat flours with the aim of
producing pasta of good textural quality, in particular low cooking loss,
optimal cooking weight and texture firmness. The results showed that pasta
produced from amaranth had decreased texture firmness and cooking time,
while pasta from quinoa mainly showed increased cooking loss. In buck-
wheat pasta the least negative effects were observed. Combining all three
raw materials in the ratio of 60 % buckwheat, 20 % amaranth and 20 %
quinoa resulted in an improved dough matrix. Additionally, by decreasing
dough moisture to 30 %, increasing the amount of egg white powder to 6 %
(based on flour) and adding 1.2 % emulsifier (distilled monoglycerides)
(based on flour), texture firmness and cooking quality of gluten-free pasta
reached acceptable values comparable to wheat pasta.

13.4.5 Fermented foods and beverages
Fermentation changes the composition of amaranth-based foods in a variety
of ways: components can be nutritionally enhanced by being broken down

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464 Cereal grains for the food and beverage industries

or altered in ways that affect other characteristics and new components can
be synthesized. Amaranth grains can be processed by fermentation in many
different ways to produce a variety of products. They can be fermented by
lactic acid bacteria (LAB) to produce ‘ogi’ (Akingbala et al., 1994), the
weaning food most commonly used in Nigeria, which is normally manufac-
tured from sorghum, millet or maize. Amaranth can also be used for the
manufacture of soy sauce (shoyu), which is widely used in Southeast Asia.
The amino acids composition of the soy sauce was more balanced and the
taste of the soy was also improved (Yue and Sun, 1997). Additionally, ama-
ranth seeds are occasionally used to produce a kind of beer in Ethiopia
(‘tala’) and in Peru (‘chicha’) (Olaniyi, 2007). Zweytick at al. (2005) varied
the process for maize beer production to produce amaranth malt and brew
100 % amaranth beer. Owing to the high specific surface of the amaranth
grain, rapid and high water absorption was considered; for this reason, a
steeping time of 1 h was considered sufficient and the applied kilning time
at 80 ºC was 24 h. Germination took place on a germination floor and the
sieve floors had to be adjusted to the very small grain diameter. Three days
of germination were sufficient for enzymatic breakdown of the starch gran-
ules (Fig. 13.7). It was found that the temperature during the steeping and
germination could exceed 30 °C; however, the germ had to be washed suf-
ficiently in order to prevent mould growth. In Fig. 13.7, it is possible to
observe how the endosperm had a very porous, open structure after malting.
The malted grain showed a slight red coloration (Table 13.12), and conse-
quently the wort was coloured slightly pink. There was sufficient soluble
protein and free amino nitrogen (FAN) in the malt (Table 13.12), but it
lacked any detectable amylolytic activity and consequently exhibited the
lowest final attenuation compared to beers brewed from other cereals/
pseudo-cereals (Table 13.12). The resulting amaranth beer was slightly
opaque. The foam stability was not good and the taste was deemed to be

×55 200 μm AMRF, UC

(a) (b)

Figure 13.7 CLSM micrograph of unmalted (a) and malted (b) amaranth kernel.

© Woodhead Publishing Limited, 2013

Table 13.12 Properties of selected cereals and pseudocereals using a standard malting regime

Attribute Barley Oats Proso Blue Black Rye Sorghum Triticale Wheat Amaranth Buckwheat Quinoa
millet maize rice

© Woodhead Publishing Limited, 2013 Extraction in d.m. (%) 82.0 64.4 63.6 60.7 87.4 89.2 73.9 88.0 86.2 79.7 52.9 83.2
Saccharification (min) < 10 < 10 < 25 no no < 10 no 10–15 10–15 no no no
Colour (EBC)
Protein (dry basis %) 2.9 3.7 2.1 3.9 7.6 2.7 7.5 0.1 3.2 5.6 2.5 5.0
Viscosity (mPas) 10.5 12.6 13.6 14.6 8.4 10.4 7.8 10.6 12.1 15.2 15.4 13.7
Soluble nitrogen 1453 1511 1404 1407 1842 6467 1959 2219 1756 1969 3507 1520
682 681 604 481 283 964 426 840 725 1022 713 888
(mg/100 g d.m.)
Degree of modification 10.7 31.8 27.8 20.6 21.1 57.9 34.1 49.5 37.4 42.0 29.7 40.5

(%) 140 145 75 119 58 121 119 123 110 187 111 206
Free amino nitrogen
311 269 78 72 82 177 83 430 405 88 77 81
(mg/100 g d.m.) 55 24 11 7 6 18 8 21 20 1 6 2
Diastatic power
α-amylase activity 82.1 77.8 80.9 52.5 51.4 68.4 79.7 75.9 80.2 22.4 46.4 63.5

(ASBC) dry basis
Final attenuation (%)

Note: The malts were prepared according to the following standard procedures. Steeping: steeping for 5 h submerged at 14.5 ºC following by 19 h of drying;
steeping for 4 h submerged at 14.5 ºC, followed by 20 h of drying; final degree of steeping 45 %. Germination: 6 days at 15 ºC. Kiln drying: 16 h at 50 ºC, 1 h
at 60 ºC, 1 h at 70 ºC, and 5 h at 80 ºC. Analyses were performed with standard methods for barley malt. The respective malts were fermented with top-
fermenting yeast (yeast strain W 68: 107 cells/ml) at 20 ºC for 1 week. Afterwards the yeast was removed and the resulting beer filled into bottles without
filtering or stabilization.
Source: Adapted from Hans Michael Eßlinger (2009). Handbook of Brewing, Process, Technology, Markets. Wiley-VCH, pages 56–7.

466 Cereal grains for the food and beverage industries

too bitter (Eßlinger, 2009). Starch from amaranth, though, in a pre-
gelatinized form can be added at levels of up to 20 % to a barley malt
without causing any problems (Zweytick et al., 2005). Sensory analysis
showed that, compared to the pure barley malt beer, the beer produced
with amaranth was judged to have better smell, taste, bitterness-quality and
full-body taste but worse bitterness-intensity and less freshness of flavour.

13.5 Conclusions

Amaranth is one of the oldest grain crops known. Amaranth possesses high
stress tolerance to drought, salinity, alkalinity or acid soil conditions. Its
grain is an excellent source of high-quality protein and lipids with higher
content of minerals, such as calcium, potassium, phosphorus, as well as
dietary fibre, than cereal grains. At the same time, it does not contain gluten
protein (prolamins and glutelins), a reason for its use in gluten-free prod-
ucts (Gupta et al., 1993). There is currently a resurgence in the popularity
of amaranth 500 years after it was eaten as staple food by ancient Meso-
americans, and it is available as part of a wide range of commercial food-
stuffs in many parts of the world. Amaranth consumption positively affects
plasma lipid profile and amaranth oil is a promising source of squalene.
Moreover, grain amaranth is being developed as an energy food to be com-
bined with traditional cereal grains in breakfast foods, bread, multigrain
crackers, pastes and pancake mixes, or popped as a snack food product.

13.6 Future trends

Amaranth is an appealing alternative to improve the spectrum of foods in
our diet and may contribute to solving the problem of malnutrition, espe-
cially for developing countries. Additionally, amaranth could represent an
excellent candidate for the crop rotation that is essential to reduce the
vulnerability of the world’s food supply to insects, disease and drought.
However, in order to reach these goals, intense and continuous research
efforts are still necessary in several areas, such as amaranth breeding and
field cultivation, relevant food and feed processing technologies and product
development. Moreover, in order to improve the popularity of this plant,
an effective commercialization plan should be put in place, building an
appropriate marketing strategy.

13.7 References

akingbala, j. o., adeyemi, i. a., sangodoyin, s. o. a. and oke, o. l. (1994). Evaluation
of amaranth grains for ogi manufacture. Plant Foods for Human Nutrition (for-
merly Qualitas Plantarum), 46, 19–26.

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