Venkatachalam Mahesh, Sathe Shridhar K
Department of Nutrition, Food & Exercise Sciences, College of Human Sciences, Florida State University, Tallahassee, Florida 32306-1493, USA.
J Agric Food Chem. 2003 May 21;51(11):3466-72. doi: 10.1021/jf026105y.
Great Northern bean (Phaseolus vulgaris L.) phaseolin proteolysis at 37 degrees C, varying HCl concentrations (10 mM to 1 M), phaseolin:pepsin ratios ranging from 5:1 to 100:1 (w/w), and incubation times up to 24 h was investigated. The results suggest that phaseolin is not resistant to in vitro pepsin hydrolysis. At a phaseolin-to-pepsin ratio of 100:1 (w/w), native phaseolin was completely digested in 24 h when incubated in 50 mM HCl, while heat-denatured phaseolin (30 min at 100 degrees C, boiling water bath) was digested in 1 h under similar conditions. When incubated at 37 degrees C for 24 h, acid alone, even at as low a concentration as 10 mM, caused a partial breakdown of native phaseolin. The degree of phaseolin hydrolysis by HCl was dependent on the acid concentration used. The rate of native phaseolin hydrolysis increased with increasing HCl concentration rather than pepsin concentration. Common food acids were able to partially hydrolyze phaseolin. Among the food acids tested, oxalic acid was the most effective in hydrolyzing phaseolin. Spectroscopic studies revealed a significant change in secondary and tertiary structures when native phaseolin was incubated in dilute HCl. None of the tested phenolic compounds adversely affected phaseolin hydrolysis by pepsin.
研究了在37℃、不同盐酸浓度（10 mM至1 M）、菜豆蛋白与胃蛋白酶比例为5:1至100:1（w/w）以及长达24小时的孵育时间条件下，大北豆（菜豆属菜豆L.）的菜豆蛋白水解情况。结果表明，菜豆蛋白对体外胃蛋白酶水解不具有抗性。在菜豆蛋白与胃蛋白酶比例为100:1（w/w）时，天然菜豆蛋白在50 mM盐酸中孵育24小时后被完全消化，而热变性的菜豆蛋白（在100℃沸水浴中30分钟）在类似条件下1小时内就被消化。当在37℃孵育24小时时，即使是低至10 mM的盐酸单独作用也会导致天然菜豆蛋白部分分解。盐酸对菜豆蛋白的水解程度取决于所用酸的浓度。天然菜豆蛋白的水解速率随盐酸浓度增加而增加，而非胃蛋白酶浓度。常见的食用酸能够部分水解菜豆蛋白。在所测试的食用酸中，草酸在水解菜豆蛋白方面最有效。光谱研究表明，天然菜豆蛋白在稀盐酸中孵育时，其二级和三级结构发生了显著变化。所测试的酚类化合物均未对胃蛋白酶水解菜豆蛋白产生不利影响。
