LIPOXYGENASE DESTRUCTION IN WHOLE SOYBEANS BY COMBINATIONS OF HEATING AND SOAKING IN ETHANOL

We treated whole soybeans with heat and ethanol (in aqueous suspensions) so that lipoxygenase activity was destroyed and nitrogen solubility index (NSI) was maximal. As pH increased from 6.8 to 8, the susceptibility of lipoxygenase to heat is greatly increased, either with or without ethanol exposure, but the pH change had little effect on NSI. Increasing the ionic strength did not enhance lipoxygenase destruction. Useful ranges of the variables are 15‐45% ethanol, 40‐60°C, and 2‐6 hr exposure. The proper combinations of these conditions are sufficient to destroy lipoxygenase and maintain NSI at 50‐60, but only 50% of soybean trypsin inhibitor is destroyed. Copyright © 1979, Wiley Blackwell. All rights reserved