Chemical and functional properties of cereal and legume proteins

Proteins are complex macromolecules that constitute around 8 to 42% of the dry weight of the plant tissue in seeds. They have a fundamental role in cellular structure and function. Nutritionally, they are a source of essential amino acids for growth, development and maintenance of the human body. As for their techno-functional properties, they affect physicochemical and sensorial characteristics of food. Elaboration of foods can affect these properties, which is a main factor in the application and development of technologies to conserve and regulate the increase of bioactive compounds. In the last years, it has been demonstrated that bioactive peptides can be present in dietary proteins like independent entities or codified within them, which can be released during gastrointestinal digestion or food processing. These peptides can be obtained through enzymatic and/or chemical hydrolysis, microbial fermentation, seed germination and/or partition of proteins or by their enrichment. The obtained peptides show a wide application as food ingredients, nitrogen source in the preparation of diets for parenteral administration, hypoallergenic formulations for infants, food with low calories and sports drinks. Their functionality depends on the number, type and sequence of amino acids constituting them, showing antioxidant, antihypertensive, cytomodulatory, opioid, opioid antagonist, antithrombotic, immunomodulatory, ion transporters, hypotensor and anticarcinogenic activities. Among the most common sources to obtain these peptides are those of animal and plant origin, highlighting legumes among the latter, in which the functional effects of several peptides and proteins have been tested in clinical studies in vivo and in vitro, finding anticancer. hypocholesterolemic, glucose and arterial pressure lowering effects, as well as antioxidant and antimicrobial activity.