The review, published in ...., brought together findings from studies that have identified amaranth as a source of bioactive peptides, with antihypertensive and antioxidative qualities.
Lead scientist Alvaro Montoya-Rodriguez said: “Amaranth grain is an alternative crop that possesses excellent nutritional and nutraceutical properties. The proteins from amaranth are excellent quality with a good balance of amino acids.”
“... It could be used as a functional food, or peptides derived from amaranth could be used as ingredients in functional foods to help in the prevention and reduction of chronic diseases.”
A ‘pseudograin’ with potential
Compared to most other grains, amaranth is relatively rich in protein – containing up to 20% – which has a high digestibility (90%). As a ‘pseudocereal’ it does not contain any gluten making it interesting for manufacturers of gluten-free foods.
“The balanced amino acid composition of amaranth is close to the optimum protein reference pattern in the human diet according to FAO/WHO requirements. The combination of amaranth and maize flour in a ratio of 50:50 almost reaches the 100 score [on the WHO protein reference pattern],” say the researchers.
The study’s authors draw attention to the versatility of the grain, which can be used in soups, stews and porridges, or boiled and used as an alternative to rice or couscous.
Flour from the seed can be used to make bread and ready-to-eat cereals. In Latin America it is also used to make candy and beverages, while the stems and leaves are used for animal feed.
In addition to its nutritional content, the plant is interesting from an agricultural perspective due to its resistance to drought-like conditions, meaning it can be cultivated in areas where other conventional crops fail.
Peptides and antioxidants
The researchers said that peptides from amaranth seed albumins and globulins had ACE inhibitory activity. ACE inhibitors are medicines used to treat hypertension and congestive heart failure. Similarly, scientists have also identified peptides associated with controlling blood glucose levels.
These peptides are inactive within the amaranth protein but can be activated either through gastrointestinal enzymes during human digestion or during food processing.
Several methods of activating the bioactive peptides during food processing exist, such as enzymatic hydrolysis, the use of chemical enzymes or high temperature extrusion, the method currently used for pre-cooked flours.
Montoya-Rodriguez et al. also draw attention to the antioxidant components of amaranth, most of which come from polyphenols, such as isoquercetin and rutin, or phenolic acids, such as syringic and vanillic acids. The amino acids also possess antioxidant capacities.
The reviewers have called for “more research in the formulation of functional foods to improve and motivate the general use of the bioactive principles from the amaranth proteins.”
Source: Comprehensive Reviews in Food Science and Food Safety
Vol.14, 2015, pp 139 – 158, doi: 10.1111/1541-4337.12125
Title: Identification of Bioactive Peptide Sequences from Amaranth (Amaranthus hypochondriacus) Seed Proteins and Their Potential Role in the Prevention of Chronic Diseases
Authors: Montoya-Rodriguez, Gomez-Favela, Reyes-Moreno, Milan-Carrillo, Gonzalez de Mejia