Compositional, structural and functional characteristics of millets as modified by bioprocessing techniques: A review

Abstract

Despite the excellent nutritive potential, millets remained underused due to different factors including the presence of anti-nutritional factors, lack of optimized processing technologies, and compromised techno-functionality of the raw flours. Bioprocessing techniques such as soaking, germination, enzymatic hydrolysis, and fermentation are the natural methods for enhancing the compositional and functional characteristics of the millets. They lead to synthesis and release of components from the wall of polysaccharides and unfolding of proteins due to the action of degrading enzymes that are produced during the bioprocessing of millets. The objective of the present article is to comprehensively review the recent investigations focusing on modulations in the compositional parameters, bio- and techno-functional attributes of millets due to different biological processing treatments. Available literature suggested these treatments caused significant changes in the protein starch matrix, phytochemical constituents, rheological properties, hydration profile, anti-nutritional factors, in vitro starch and protein digestibility, structural and molecular modification. Practical applications Present day food market is driven by functional foods owing to the diet-health relationship. Millets are preferred ingredients over conventional grains for value-added products attributing to their excellent agrarian and nutritional profile; however, native millet flours lack bio-techno-functionality due to structural features and presence of anti-nutritional compounds. Bioprocessed millets possess improved functionality and bioactivities, which make them ideal ingredients to develop cereal based functional foods. Utilization of germinated and fermented millets in convenience food products could not only enhance the bio-functionality of the food but also add to the variety of functional foods especially to targeted populations such as for those with celiac disease and other similar chronic complications. Cereal based industries are looking such ingredients to replace conventional wheat based products in bakery, extrusion, and indigenous preparations.