Solubility and Emulsifying Properties of Soy Protein Isolates Modified by Pancreatin

摘要

Soy protein isolates (SPI) with varying degrees of hydrolysis (DH of 7, 11, 15, 17/100) were produced using pancreatin. The surface hydrophobiclty indices of pancreatin hydrolyzed SPI (PSPI) (34.5, 34.9, 39. 1, and 40.7 for 7, 11, 15, 17/100 DH, re- spectively) were higher than that of SPI (10.5) and control SPI (CSPI) (12.5, 11.9, 12.9, and 12.6 for 10, 60, 120, and 180 rain incubation, respectively). The solubilities of PSPI at pH 4.5 were 2.7, 9.1, 11.9, and 18.7/100, for 7, 11, 15, and 17/100 DH, respectively, while the solubilities of SPI and CSPI at the same pH were about 1.6/100. Solubilities of PSPI at pH 7.0 were > 90/100 for all DHs tested, while those of SPI and CSPI were 85/100. The emulsifying activity index (EAI) of PSPI increased with increasing DH. PSPI with 15/100 DH had highest EAI (1. 122) which was higher (P < 0. 05) than those of SPI (0.550) and CSPI after 120 rain incubation without enzyme (0.568). These results suggest that PSPI could be used as an ingre- dient for emulsified products and where high solubility at low pH is required.