29-11 |
|
R. E. ALUKO, Dept. of Human Nutritional Sciences, Univ. of Manitoba, 400-A Human Ecology Bldg., Winnipeg, MB R3T 2N2, Canada and H. Aukema, Human Nutritional Sciences, University of Manitoba, 190 Dysart Road, Winnipeg, MB R3T 2N2, Canada. Previous scientific data have shown that consumption of soybean proteins provided substantially higher physiological benefits than casein. The types of bioactive peptides that are produced during gastrointestinal digestion of proteins may be responsible for some of the differences in physiological benefits observed between soybean and casein. The aim of this work was to determine (in vitro) some properties of peptides obtained from simulated gastrointestinal digestion of soybean proteins and casein. Soybean protein isolate and sodium caseinate were each digested sequentially with pepsin followed by trypsin and chymotrypsin. The protein digests were passed through an ultrafiltration membrane with 3,000 molecular weight cut-off and the permeates used for further analysis. Casein peptides had significantly higher (P<0.05) angiotensin converting enzyme (ACE) inhibitory property when compared to soybean peptides. Relative scavenging activity (RSA) was similar for soybean and casein at peptide concentrations lower than 1.5 mg/ml. However, at concentrations >1.5 mg/ml casein peptides had significantly higher (P<0.05) RSA than soybean peptides. Casein peptides also had significantly higher (P<0.05) ability to prevent lipid oxidation as measured by the thiobarbituric acid method. The results indicate that the physiological benefits of soybean protein consumption may not be due to the ACE-inhibitory or antioxidative properties of the peptides that are produced during gastrointestinal digestion. Further work is being carried out to determine other bioactive properties of the soybean- and pea-protein derived peptides.
Session 29, Food Chemistry: Antioxidants and bioactive agents
|