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Trypsin Inactivation in Soybeans

August 2019

Trypsin inhibitors are present in raw soybean meal and in several meal fractions.  At least four inhibitors have been separated on DEAE-cellulose columns.  All of these fractions can be inactivated by steam heating resulting in an improvement of protein efficiency, improvement of protein digestibility, and destruction of the pancreatic hypertrophic factor.  Dr. Rackis found that trypsin inhibitors in defatted soybean flakes can be inactivated by steaming for 15 minutes. Steaming for 20 minutes almost completely inactivates the inhibitor in whole beans containing 25% moisture.

Bottom line- The soybean processing industry uses the heat-moisture conditions during soybean processing to inactivate trypsin and produce meals with maximum nutritional value.  Therefore, the trypsin inhibitors in soybeans are mainly academic since commercial processing inactivates these compounds and produces soybean meals of highest quality for those species sensitive to these natural inhibiters.