LI Junwen,FAN Wenlai, XU Yan
The non-volatile carboxylic acids in Zhenjiang balsamic vinegar were derivatized by N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) and detected by gas chromatography-mass spectrometry. A total of 61 non-volatile compounds were identified, including 17 amino acids, 13 aromatic acids, 11 hydroxy acids, eight long-chain fatty acids, seven dicarboxylic and polyhydric acids (no hydroxyl groups), one sulfur-containing organic acid, one keto acid, two heterocyclic acids, and one non-volatile ester acid. Among them, the concentrations of hydroxy acids were the highest (16.01 g/L), followed by heterocyclic acids (597.3 mg/L) and amino acids (546.5 mg/L). There were 24 newly identified non-volatile organic acids, including 2-furoic acid, glycolic acid, 3-hydroxypropionic acid, glyceric acid, mandelic acid, p-hydroxyphenylacetic acid, 2,6-dihydroxybenzoic acid, protocatechuic acid, ferulic acid, citric acid, sinapinic acid, gallic acid, and caffeic acid. In which, lactic acid, pyroglutamic acid, succinic acid, arginine, oxaloacetic, and 2-hydroxy-3-phenylpropionic acid were higher than 100 mg/L. These results lay a foundation to improve the quality of Chinese vinegar.