Changes of Aroma Compounds of Jujube Vinegar at Different Fermentation Stages

Solid phase micro-extraction coupled with gas chromatography mass spectrometry(SPME/GC-MS) technique was applied in isolation and identification of aroma compounds of the products in different liquid fermentation stages including the initial jujube juice, the jujube wine mash and the jujube vinegar. The results showed that 56, 56 and 54 kinds of aroma components were identified in the three stages, accounting for 94.57%, 97.37% and 98.86% of the total aroma, respectively. The main aroma components were hydrocarbons, acids, esters, alcohols, aldehydes, ketones, and a small amount of other compounds. The number of aroma components in three products showed little difference, but the component ratio and relative content were significantly different. In the alcohol fermentation process, hydrocarbons content increased significantly, the acids content increased slightly, and the ester and alcohol contents decreased. In the acetic fermentation process, the alcohols and aldehydes contents decreased while the contents of acids and esters increased significantly. These acids and esters were the main components of aroma compounds, and a small amount of hydrocarbons, alcohols, aldehydes, ketones were also an indispensable part of the aroma. These aroma compounds endowed jujube vinegar the unique flavor and quality.