열처리 방법에 따른 대두의 이화학적 특성 변화

Abstract

Soybean is one of the most common food materials for making traditional Korean foods such as soybean paste, soy source and soy snack, and their manufacturing processes include heat treatment of soybean. This study was carried out to investigate the effect of heat treatment on the physicochemical properties of soybean. All samples were heat treated under commercial steamed, puffed or air-fried conditions, and then the protein molecular weight distribution, thermal properties, fluorescence intensity, protein solubility, and water and oil holding ability of the heat treated soybeans were examined. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that heat treatment caused fragmentation of polypeptide chain in soybean, showing the band of low molecular ranging from 17 to 40 kDa. The differential scanning calorimetric analysis showed the decrease of enthalpy values (ΔH) by heat treatment. Fluorescence spectroscopy indicated that the heat treatment caused lipid oxidation as proved by increasing emission intensity. The protein solubility at pH 3-6, and water holding capacity of heat treated soybeans were the higher than no treatment. These results suggest that the heat treatment resulted in decreased enthalpy values, and increased protein degradation, lipid oxidation and water affinity of soybean. Moreover, the effect of heat treatment on physiochemical properties of soybeans was more significant under air-fried condition.