Functional Attributes of Amaranth

Review Article

Austin J Nutri Food Sci. 2014;2(1): 1010.

Functional Attributes of Amaranth

Priscila D. Santiago*1, Klaus Tenbergen2, Elier Vélez-Jiménez1, Maria Anaberta Cardador-Martínez1

1Tecnológico de Monterrey, Campus Querétaro, México

2Jordan College of Agricultural Sciences and Technology, University, Fresno, USA

*Corresponding author: :Priscila D. Santiago Mora, Tecnológico de Monterrey, Campus Querétaro, Epigmenio González 500; Col. San Pablo, Querétaro, Qro. 76130, México

Received: January 10, 2014; Accepted: February 10, 2014; Published: February 17, 2014


Amaranth is a plant with high nutritional value, whose nutrients are concentrated in the leaves and the grains. The plant has compounds that showed to have many health benefits, which are mostly present in the oil extracted from the seeds. Most pronounced are: unsaturated fatty acids, lectins, tocopherols, tocotrienols, phytosterols, squalene, isoprenoid compounds, aliphatic alcohols, terpene alcohols and polyphenols, which have properties related to enhancing the immunity system, protection against cancer, prevention against oxidation, control serum lipid levels, decrease pain and inflammation. On the other hand, its components have industrial applications in the market sectors of food production (betalains and carotenoids as antioxidants and natural pigments), cosmetics (squalene) and biodegradable utensils (cellulose). Including amaranth as regular food component in the diet, whether natural or processed, will allow complementing a healthy life style.

The continuing research of the amaranth as a pseudo cereal, based on its biotechnological properties, can advance the amaranth plant from a simple pseudo cereal into an important source of nutraceuticals.


Amaranth is a dicotyledon from the Amaranthaceae family [1]. It is cultivated mainly in the former (now Russia), China, Mexico, Guatemala, Peru, India and Kenya. The species grown for human consumption are: Amaranthus hypochondriacus L., A. cruentus L. and A. caudatus L. [2]. In Mexico, the domesticated specie is A. hypochondriacus [1] which is mainly harvested in warm regions of the States of Morelos, Puebla and Guerrero [3]. This plant offers agricultural advantages as to be resistant to drought, high temperatures and saline soils, hence its name in Greek, which translation means “unfading flower” [2,4].

It is used in human and animal products as well as forage, silage and green manure. It has potential industrial uses in cosmetology and biodegradable plastics [2].

In the past decades the study of amaranth properties has deepened. Because of its similarity with other cereals, it has been considered a pseudo cereal. Its high nutritional quality places it as a plant that can potentially contribute to the world food demand [2].

Green parts of the plant are rich in protein, minerals (potassium, iron, magnesium and calcium) and vitamins (A and C). Its leaves are also consumed in a diet; by their appearance, texture and nutritional quality, are comparable to spinach [5].

The protein content of the amaranth grain ranges between 13 and 19 % [2], which is qualified as high nutritional value [4] due to its composition (Table 2).

This nutritional value is very balanced and close to the optimum required in the human diet, as described by the World Health Organization (WHO) and Food and Agriculture Organization of the United Nations (FAO). The amount of lysine is two to three times higher than wheat, rice and maize; the concentration of sulfur amino acids is greater than legumes, which makes it an important and inexpensive source of protein [5]. Its tryptophan content is also satisfactory, but it is deficient in leucine [6].

Amaranth represents a foodstuff with high calorie content, since it has 1.5 – 3 times more oil than other grains [2]. Its starch content is close to other important cereals [5].

In addition for its nutritive value as part of human consumption, amaranth has molecules that have health benefits, such as:

Amaranth seeds and leaves also contain anti– nutritional and toxic factors like large amounts of oxalates (which limit the availability of nutrients), nitrates and saponins [5].

In the food industry, the amaranth is processed as food or used as an ingredient in prepared products (breads, cereals, crackers, granola, etc.) [12]. Although the use of its seeds has been limited by the content of saponins and phenolic compounds give unpleasant bitter flavors [6].

The seeds have colors ranging from pale yellow to black (due to its protein content), gold, coffee and pink [5,6,8]. Betalains are present in leaves pigment [12]. The different patterns of pigmentation of the amaranth contributes to many practical and aesthetic uses, [1] when correctly extracted, allowing it to be used as a natural dye [12].

Amaranth Betalains

The natural pigments, in addition to being used as dyes, also have antioxidant, anti–inflammatory, antibacterial, and anti–cancerogenic properties. It has been found to reduce the risk of cardiovascular disease and other diseases related to ageing [24,25]. It has been shown that betalains of beet, in low concentrations, inhibit lipid peroxidation; the same antioxidant effect was observed with betalains of prickly pear, the anthocyanins of fig and aloe extracts [26,27,28].

Betalains are water–soluble pigments that contain nitrogen. Betalamic acid is its predecessor [29]; they are synthesized from the amino acid tyrosine into two structural groups: the betacyanins, composed of red–violet color, and the betaxanthines, yellow–orange. The betacyanins contain a residue cycle–3, 4–dihydroxyphenylalanine (cycle – Dopa) that extends the resonance of the aromatic diphenolic ring and change the maximum of 480 nm (betaxanthines) absorbance to 540 nm (betacyanins) [30]. Different substitutions or glucosilations [31] of the sulfate (the betacyanins aglycone) resulting in the formation of different betacyanins, which in turn have a change hypsocromic of 6 nm in the UV range maximum absorbance [32]. The betaxanthines, on the other hand have changes in their chains of amino and these modifications have a lower maximum absorbance than their counterparts (barochromic effect) [33].

For its extraction, plant tissue is macerated. Pigments can be extracted with water, but solutions of methanol or ethanol achieved a complete extraction [31]. A means of extraction slightly acidified promotes the stability of the betacyanins and avoids oxidation caused by the polyphenoloxidases [33]. An enzymatic method for degradation of hydrocolloids in the material, also favors the extraction of this pigment [34].

Extract purification is done while stirring it with water and filtering it to a vacuum. Using a fraction with ethyl acetate extraction, will separated the phenolic compounds of betalains. The aqueous fraction contains betalains, while the organic contains the rest of the phenolic. Betalains were adjusted to a pH of 6 with aqueous ammonium and concentrated solution to be analyzed in the HPLC–MS [32].

Of the 70 betalain structures identified (50 betacyanins and 20 betaxanthines), 16 betacyanins and 3 betaxanthines are present in the family Amaranthaceae [35]. In a comparative study of the beet betalains versus the amaranth, it was concluded that the presence of the following betacyanins are present: amaranthine, isoamaranthine, betanin and isobetanin, the first two being the most predominant [32]. The structure of the molecules of betalains found in the family Amaranthaceae can be seen in figure 1.

ABTS and DPPH are laboratory tests used to evaluate the power of betalains as free radical scavengers. Studies have shown that its antioxidant activity is very diverse in the different molecules [24], which compares various betalains and other antioxidants (table 1). EC50 is a widely used parameter to express and compare antioxidative power in certain molecules.


Citation: Santiago PD, Tenbergen K, Vélez-Jiménez E, Cardador-Martínez MA. Functional Attributes of Amaranth. Austin J Nutri Food Sci. 2014;2(1): 1010. ISSN: 2381-8980.