Amaranth grain proteins: prospects for use in specialized food products

Amaranth is a widespread genus of predominantly annual herbaceous plants belonging to the Amaranthaceae family, which is one of the most widely used pseudocereals along with quinoa and buckwheat in nutrition. The aim of the research was to review and analyze the results of the studies on the characteristics of amaranth grain proteins, the effect of various food processing methods on their quality, and the prospects for using amaranth protein hydrolysates in therapeutic nutrition. Material and methods. For the main search for the literature, the PubMed bibliographic database was used, which covers about 75% of the world's medical publications. In addition, Scopus and Web of Science databases and non-commercial search engine Google Scholar were used. The depth of the search was 15 years. Results. The paper presents a brief review of modern approaches for obtaining amaranth protein isolates and concentrates, including the use of a complex of physicochemical methods: grinding, sifting, extraction at high pH values, defatting, ultrafiltration, centrifugation, isoelectric precipitation, and drying of the protein product. A comparative characteristic of amino acid content of protein fractions of pseudocereals is presented. Basically, leucine, isoleucine, and valine are limiting amino acids for the grain protein of various varieties of amaranth. When substantiating and developing modern effective food technologies for processing amaranth grain, the studies dedicated to the evaluation of their impact on the biological value of amaranth protein deserve special attention. Methods of grain fermentation, sprouting, steaming, malting, boiling can be used to increase the bioavailability and digestibility of its ingredients. The results of in vitro and in vivo studies indicate the presence of hypotensive, hypolipidemic and antioxidant activity of the amaranth protein and its hydrolysates what determines the prospects for their use as part of foods for special dietary uses and therapeutic nutrition. An analysis of the scientific publications presented in the review indicates an increase in demand for high-quality gluten-free products and an increase in the range of mass-consumption foods, such as bakery, pasta, flour confectionery, with pseudo-cereals in their composition, including amaranth. Conclusion. The high biological value and technological properties of amaranth protein concentrates/isolates determine the prospects for their use to create a wide range of specialized foods for various purposes.