NUTRITIONAL-EVALUATION AND METABOLIC EFFECTS IN RATS OF PROTEIN ISOLATES OBTAINED FROM SEEDS OF 3 LEGUME SPECIES

Three legume seeds, peas (Pisum sativum L), faba bean (Vicia faba L) a nd soybean (Glycine max L) and their respective protein isolates, were assayed for their nutritional value and metabolic effects. Feeding ra ts with either the legume seeds or the protein isolates resulted in an impairment in growth and significantly lower nutritional indices as c ompared to the control group. Protein apparent digestibility improved in the protein isolate fed rats, with similar digestibility data to th ose observed in the casein fed group. Liver, gastrocnemius muscle and spleen weights were decreased by legume consumption, and the enlargeme nt detected in the small intestine weight in the animals fed on the le gume seeds, was partially reversed in the animals receiving the protei n isolate. This reversal was significant in rats offered faba bean pro tein isolate. Biochemical parameters were consistent in the legume gro ups, and hypoglycaemic and hypotriacylglycaemic responses were observe d for the legume meals. Lower uric acid levels were found in some of t he legume fed animals. Serum free amino acid profiles were affected by the legume intake, as compared with casein. Methionine and taurine co ncentrations decreased, whereas serine concentrations were augmented. Other amino acids, particularly glycine and valine, also showed modifi ed plasma concentrations. These results suggest that the preparation o f protein isolates, following an easy protocol, yield products with be tter digestibility, which keep the positive effects on glucose and tri acylglyceride plasma levels, and partially reduce some other undesider able consequences related to legume consumption. (C) 1998 Society of C hemical Industry.