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. Multiple steam treatments were evaluated in the processing of soybeans to assess effects on trypsin inhibitor activity.
Results indicated 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.