ABSTRACT
Processed proteins are increasingly used to meet human dietary needs. Alkali treatment of casein, corn, and soy proteins brings about desirable changes in flavor, texture, and solubility. Such treatments, which are used to prepare protein isolates, also destroy toxins and trypsin inhibitors. Treating food protein with alkali and heat may, however, produce undesirable changes in the constituent amino acids. The amino acid l-Tyr is an in vivo precursor for brain catecholamine, dopamine, and norepinephrine; for the biogenic amine tyramine, and for the ubiquitous pigment melanin. The described results with mice complement related studies with other species and contributed to the understanding of nutritional and toxicological consequences of ingesting d-amino acids. Such an understanding will make it possible to devise food-processing conditions to minimize or prevent the formation of undesirable d-amino acids in food proteins and to prepare better and safer foods.
