RESUMO
This study was designed to investigate the effects of supplementing soy peptide on isometric performances and serum CK and LDH trends after a high intensity eccentric exercise stress. Study subjects consisted of 13 males and were divided into 2 groups. They were instructed to take 4,000 mg of soy peptide or placebo orally before and for 7 days following the initial exercise stress. Soy peptide group revealed significantly faster improvements in knee extension performance at 72 hr-post the eccentric exercise (p<0.05). Comparing with placebo group, soy peptide group showed significantly lower serum LDH activity 168 hr after the exercise (p<0.05), while as to serum CK levels, significant difference was not observed between those 2 groups. These results indicate that oral supplementation of soy peptide could induce not only reduction in serum LDH activity level, but also faster recovering in isometric performance after high intensity repetitive eccentric exercise.
RESUMO
Penetration of different kinds of peptides or collagen peptide through the intestinal membrane was studied in two experiments using an<I>in vitro</I>rat everted intestine penetration model. In Study 1, twelve 11-wk-old rats (Wistar strain) were randomly divided into two groups and penetration of whey peptide (n=6) and soy peptide (n=6) through the intestinal membrane was compared. In Study 2, fourteen 11-wk-old rats (Wistar strain) were divided into a control group (n=7) and a training group (treadmill running at a speed of 20-35 m/min for 15 mm day, 5 days wk for 4 wk n=7), and penetration of collagen peptide through the intestinal membrane was investigated in the two groups. In Study 1, the quantity of whey peptide that penetrated through the intestinal membrane was significantly greater than that of soy peptide (P<0.01) . In Study 2, body weight was significantly lower in the training group than in the control group except during 12 and 12.5 wk of age (13.5 wk ; P<0.01, others; P<0.05) . The weights of heart, kidney, and spleen were significantly increased, and the weight of fat was significantly decreased in the training group compared to the control group (P<0.05, P<0.05, P<0.01, P<0.05, respectively) . In both groups, a portion of collagen peptide penetrated through the intestinal membrane; but there was no significant difference in quantity between the two groups. In conclusion, the inhibition of weight gain in the training group was possibly caused by decreased feeding from lack of appetite with enforced exercise. These findings suggest that whey peptide penetrated through the intestinal membrane in greater quantities than soy peptide, and collagen peptide is not affected by enforced exercise.
RESUMO
Objective: To investigate if angiotensin converting enzyme inhilitory(ACEI) peptides would be produced from SPI digested by a batch digestion system using enzymes similar to digestive enzymes in humans.Method: Simulate the conditions of human gastrointestinal digestion in a model digestion system in vitro and produce soy peptides from SPI digested using pepsin and pancreatin.In addition to monitoring ACEI activity in the total soy protein digest,the possibility of generating soy peptide fractions with more potent activity than the unfractionated digest was investigated by measuring activity of fractions obtained after ultrafitration,anion exchange,and RP-HPLC.Results: The generation of ACEI activity in SPI was determined after sequential digestion with pepsin and pancreatin.The inhibitory activity was highest within the first 20 min at pepsin digestion and decreased upon subsequent digestion with pancreatin.An IC50 value of 0.28?0.06 mg/ml was determined after 180 min of digestion,while no ACEI activity was measured for the undigested SPI at 0.73 mg/ml.Chromatographic fractionation of the SPI digest resulted in IC50 values of active fractions ranging from 0.13?0.03 to 0.93?0.08 mg/ml.Conclusion: Many different peptides with ACEI activities were produced after pepsin-pancreatin digestion of SPI in vitro and lead to the speculation that physiological gastrointestinal digestion could also yield ACE inhibitory peptides from SPI.