Author : Pham Binh Chay

Summary : The study was conducted to determine the effects of process temperature, moisture content, pH and screw speed on the development of texturized cowpea (CP), mung bean (MB), defatted soybean (DSB) and air classified mung bean (ACMB) proteins by the extrusion process. As the process temperature was increased nitrogen solubility index (NSI), disulfide group (S-S group), available lysine (AL), trypsin inhibitor activity (TIA), lipoxygenase activity (LA), peroxidase activity (PA), thiamine retention (TR) for extruded products and Warner Bratzler shear (WBS) value extruded CP and MB products decreased, while water absorption capacity (WAC), sulfhydryl group (SH group), total sugars (TS), reducing sugars (RS) extruded products and WBS value for extruded DSB and ACMB products increased. As the pH buffer was increased, NSI, WAC, SH group and RS increased, but the S-S group, AL, TS, TIA, PA, and TR decreased. The pH buffer, however, increased from 7.0 to 7.4, RS decreased in extruded CP and MB products. The rate of inactivation of lipoxygenase increased at pH buffer of 6.2 or 7.4 and was lowest at pH 6.8.