Kinetics of Quality Changes during Vacuum Frying of Germinated Soybean Seeds

Abstract

The effect of vacuum frying process on the quality of germinated soybean seeds was evaluated to develop the empirical models for description of the water loss, oil uptake and bioactive compounds degradation during frying. Germinated soybean seeds were subjected to the frying at vacuum pressure of 660 mmHg and the temperatures of 130, 140, and 150°C up to 12 minutes with 1 minute intervals. The plots of the water and oil contents versus the frying time were recorded. They showed first-order exponential kinetic models adequately predicted the water loss and oil uptake and there was a strong relationship between oil uptake and moisture loss during frying of germinated soybean seeds. The degradation kinetics of total polyphenol content (TPC) and vitamin C during frying were well represented by first-order reactions. The temperature dependence of the kinetic constants was described by an Arrhenius type equation. The activation energies for moisture loss, oil uptake, TPC and vitamin C degradation were 24.15, 18.74, 21.37 and 60.59 kJ molˉ¹, respectively.