Antioxidative Activities of Miso and Soybean Sauce on Linoleic Acid

Studies on Antioxidative Activities of Amino Compounds on Fats and Oils. Part V

Abstract

Both miso (soybean fermented food in Japan) and soybean sauce showed antioxidative activity and their effects were proportional to the nitrogen content and coloring degree, respectively. Correlation coefficients between antioxidative activity and nitrogen content of miso and soybean sauce were 0.811 and 0.823 and the coefficients between antioxidative activity and coloring degree were 0.882 and 0.533, respectively. Although the hydrolyzing ratio of protein in miso is in the range from 12 to 30%, the lower was the ratio, the stronger antioxidative activity was detected. Copper and iron in soybean sance showed prooxidative activity on linoleic acid. Thus, correlation coefficient between antioxidative activity and copper or iron contents of soybean sauce was -0.624 and -0.601, respectively.