Production of angiotensin I - converting enzyme inhibitory peptides from gelatin and ovalbumin by protease

• Main Authors: Chien - Hui Weng, 翁千惠
• Other Authors: Tsun - Chung Tsai
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/63467052831418397447

碩士 === 東海大學 === 食品科學系 === 92 === Part I Production of angiotensin I—converting enzyme inhibitory peptides from gelatin by protease Growing pigs is a major animal industry in Taiwan and the yield of porcine skins is excess. If we take good advantage of them, breeders will increase incomes and get high economy value. The gelatins from porcine skins have been used in food, medicine and industry. However its applicable quantity and value is still contains needed to be promoted. The amino acid sequence of gelatin is simple and regular repetition sequences (Pro — x — Gly — Pro). The objective of this investigation is to prepare Angiotensin I — converting enzyme inhibitory peptide hydrolysate from gelatin by using suitable proteases. And the hydrolysates could be added to drink or food as health food. Five commercial proteases have been tested in studying production of ACE inhibitory peptide from porcine skin gelatin. Trypsin showed much better than others in production of ACE inhibitor in first two-hour hydrolysis and esperase turned out to be the best one and collagenase next in following four — eight hours hydrolysis. Base on the cost of enzyme and time consumption in hydrolysis, trypsin and esperase were chose in production of ACE inhibitory peptide. Results of kinetic study indicated that optimal condition to hydrolyze 2 % gelatin solution (pH 8) was digested first by 0.2 % trypsin for 1hr at 37 ºC, then 0.2 % esperase for 2 hr at 60 ºC to have inhibition activity around 60 %. The final hydrolysate is pale yellow in color, blend in taste, and no microbial contamination. L , a , and b of hydrolysate were found to be 96.58 , 1.79 and 5.27 respectively. Freeze — dried powder is pale yellow in color. Further fractionation of hydrolysate by ultra-filtration, ACE inhibition of fractions of MWCF 3000 was found to be 77 % ACE inhibition. Inhibition of activity hydrolysate was stable to pepsin digestion, and increased by pancreatin digestion. Part II Production of angiotensin I-converting enzyme inhibitory peptides from ovalbumin by protease Eggs are high nutritive food with balance amino acids. Because of high cholesterol content, eating whole eggs is limited. The objective of this work is to prepare Angiotensin I — converting enzyme inhibitory peptide from egg white by suitable proteases. And the hydrolysates can be added on drink or food to promote its economy benefit. The experiment result showed the optimal condition for hydrolysis was that 1 % ovalbumin solution (pH 8) was digested by 0.2 % thermolysin for 4 hr at 60 ºC to have IC50 value 33 μg / ml (yield of 87 %). IC50 of hydrolysate filtrate from further fractionation with MW cut — off 1000, 3000, and 1000 were found to be 58、43、25 and 14 μg/ml respectively. Hydrolysate is pale yellow in color and bland in taste with high acceptability. Inhibition activity of hydrolysate was found stable to pepsin digestion, and pancreatin digestion. The two substrates are prepared ACEI. And the result shows that ACEI from ovalbumin is better.