Abstract:

A spectrometric method has been established and announced by ISO for determining trpsin inhibitor activity of soybean-based animal feed. The method, however, has several defects, which restrict its application and popularization. Therefore this study aimed to improve this method to achieve rapid and accurate determination of trpsin inhibitor activity of soybean-based food products such as soybean milk powder, etc. The improvement mainly focused on sample preparation. The results showed that the determination results were basically identical when sample was crushed to particle sizes of 80 and 100 mesh, higher than those of the samples with the particle size less than 80 mesh. Removal of fat from sample and filtration of the prepared trpsin inhibitor solution had no significant effects on determination result. The optimal extraction effect of trpsin inhibitor from sample could be achieved by stirring the mixture of the sample and distilled water for 30 min. The improved method has high accuracy and precision, and is time-saving.

Key words: soybean products, trypsin inhibitor activity (TIA), determination