Richa Kusuma Wati, Theerapong Theppakorn, Soottawat Benjakul, Saroat Rawdkuen
The trypsin inhibitor from navy beans (Phaseoulus vulgaris), red kidney beans (Phaseoulus vulgaris L.), and adzuki beans (Vigna angularis) provided by the Royal Project Foundation in Thailand was isolated by heat and ammonium sulfate (AS) precipitation. Incubation at 70 °C for 10 min produced the highest trypsin inhibitor recovery for all legumes. The AS precipitation with 60% to 80% saturation (precipitate IV) resulted in 41-, 88-, and 34-fold of the purity and (-)26%, 126%, and (-)47% of percentage of activity increase for navy beans, red kidney beans, and adzuki beans, respectively. The trypsin inhibitors had a molecular weight of 132 kDa for navy beans, 118 kDa for red kidney beans, and 13 kDa for adzuki beans under nonreducing conditions. The obtained precipitate IV fraction from each legume effectively prevented the degradation of the tilapia muscle with concentration dependent. The myosin heavy chain increased as the concentration of the inhibitor fraction increased, especially at the highest level of addition. The result indicated that the precipitate IV from these legumes have potential for use as a protease inhibitor in fishery related products. © 2010 Institute of Food Technologists®.
School of Agro-Industry, Mae Fah Luang Univ., Chiang Rai 57100, Thailand; Dept. of Biotechnology Agro Industry, Faculty of Agriculture, Brawijaya Univ., Malang 65145, Indonesia; Dept. of Food Technology, Faculty of Agro-Industry, Prince of Songkla Univ., Hat Yai, Songkhla, 90112, Thailand
