Changes of trpysin inhibitor (TI) activity existing in soybean milk, whey and curd were investigated to improve the ripening condition of cheese-like product.
1) The degree of residual TI activity in soybean milk samples after heat treatment are as follows: 100°C for 10min., 32.8-33.9%; 100°Cfor 20min., 27.4-31.3%; 120°C for 10min., 10.8-15.1% and 120°C for 20min., 3.5-8.1%.
2) Trypsin inhibitor activity units per mg of solid matter were 0.31 and 0.05 in whey samples treated at 100°C for 10min. and 120°C for 20min., respectively. In curd samples, they showed 0.19 and 0.09, respectively. Total TI activity existing in curd samples showed higher than that in whey samples.
4) Protease activities, produced by Pen. caseicolum, under the condition at pH 6.7 and 7.6 were little inhibited by the addition of unheated soybean milk sample and curd made from heat treated soybean milk (120°C for 20min.).