ZHAO Jiahao, ZHOU Tao, LIU Shuang, SHI Lei, WANG Chunling
The organic acids, free amino acids, volatile flavor compounds, as well as the physical and chemical indexes of soy sauce, were analyzed by high performance liquid chromatography, amino acid analyzer and solid phase microextraction-mass spectrometry. The results showed that there were significant differences in amino acid nitrogen between Chinese and Japanese soy sauce (P<0.05), however, the salinity, pH, total acid, total nitrogen and reducing sugar were not significantly different. Seven kinds of organic acids were detected in soy sauce including tartaric acid, formic acid, malic acid, lactic acid, acetic acid, citric acid and succinic acid. The content of glutamic acid, glycine, lysine and arginine had significant differences (P<0.05). 17 kinds of different volatile flavor compounds in soy sauce samples from China and Japan were found by orthogonal partial least squares discrimination analysis including ethylbenzene, 1-ethyl-4-methyl-benzene, 1,3-diethyl-benzene, 1,2,3-trimethyl-benzene, ethyl acetate, ethyl linoleate, butyric acid Butyl ester, 2-phenylethanol, 1-butanol, 2,3-butanediol, 2-methyl-1-butanol, 3-methyl-1-butanol, ethanol, 2-methyl-1-Butyraldehyde, 1,2,4-trimethyl-benzene, o-xylene, p-xylene. According to the odor activity value and the flavor dilution factor, ethyl acetate, 2-phenylethanol, 3-methyl-1-butanol, ethanol, 2-methyl-1-butanal and 2-methyl-1-butanol were the key compounds that showed the difference in soy sauce flavor between China and Japan.
