Combination Effect of Alkaline Carbonate Buffers and Blanching Time on Lipoxygenase Inactivation and Protein Extractability.

Abstract

Soybean, S.J.4. were studied in order to develop the suitable method for deflavoring the beany flavor with retainable nutritive value. The beans were soaked overnight in 0.5 M. carbonate buffer at pH 9.0, 9.6 and 10.1, than subjected to heat treatment at boiling temperature for 0.5, 1, 3, 5 and 10 minutes. It was found that the carbonate buffer solely can inactivate lipoxygenase 28-37%. Combination of soaking and blanching increased the rate of enzyme inactivation. Residual enzymes in carbonate buffer pH 9.0, 9.6 and 10.1 soaked bean were 21% , 20% and 16% respectively after blanching for 10 minutes as compared to 40% in water soaked bean. However, most of enzymes were destroyed during the first minute of blanching. Protein extractability was decreased as blanching time increased. The pH 9.0 carbonate soaked bean yielded the highest protein extractability. This experiment showed that the suitable condition for deflavoring of soybean was to soak in carbonate buffer pH 9.0, then blanched for 1 minute. This method would inactivate lipoxygenase more than 60% and retain protein extractability higher than 45%.