Acta bioquímica clínica latinoamericana
Print version ISSN 0325-2957
GARCIA, Milaidi; AGUDELO, Rafael and SAVOIE, Laurent. Effects of casein or soy hydrolysates on glucose metabolism in rats. Acta bioquím. clín. latinoam. [online]. 2012, vol.46, n.2, pp. 233-246. ISSN 0325-2957.
To determine the effects of different peptide mixtures on glycemic regulation in rats, plasma glucose, insulin and amino acid responses were monitored after gavage administration of different casein or soy digests obtained by in vitro hydrolysis. Peptides present in hydrolysates were separated combining dialysis, low pressure ion-exchange chromatography and ultrafiltration. Two intact proteins (casein and soy isolate), three peptide mixtures obtained from each protein and two free L-amino acid mixtures simulating dietary protein compositions were tested. The insulin responses after administration of the three casein peptide solutions were not significantly different (p<0,05). However, rat groups fed casein material had higher insulin concentrations than those fed soy material, except for animals fed soy peptides with molecular weight between 10 and 1 kDa (S10-1). Also, the insulin response after S10-1 gavage was statistically higher (p<0,05) than other soy-peptide solutions tested. Significant increase in insulin secretion was observed by rat groups after free L-amino acid gavages. The insulin response showed strong correlation with plasma Thr (p<001, r=078), Glu (p<001, r=085), Pro (p<001, r=076), Ala (p<005, r=066), Met (p<005, r=071), Phe (p<005, r=069) and His (p<005, r=071) concentrations. Results with soy peptide fractions indicate that the insulin secretion in rats can be influenced by the nature of the peptidic fraction administered, whereas in casein, these differences were not observed between digests.
Keywords : Digestion; Hydrolysates; Protein; Peptides; Amino acids; Insulin; Glycaemia.