Standardization of Trypsin Inhibitor Extraction from Kidney Bean and Cumulative Effect of Temperature, Incubation Time and pH on Its Activity

This work investigates the factors affecting the extraction of trypsin inhibitor from kidney bean (Phaseolus vulgaris) seeds. Trypsin inhibitor extracted with 0.1% NaCl rendered a higher recovery than other solvents. The extraction was also affected by pH and extraction time. It took 5 h for complete recovery of trypsin inhibitor activity. Response surface methodology was used to study the effect of temperature and pH with respect to time on the extraction of trypsin inhibitor. Statistical optimization studies revealed that trypsin inhibitor activity from kidney bean flour was stable to 60°C for 52 min at neutral and acidic pH and labile under strong alkaline conditions.