Dynamic Research On Aroma Components Of Shanxi Aged Vinegar During Xunpin Process

Shanxi aged vinegar with color, aroma, alcohol, thick and acid five characters, is on the first of the four famous Chinese vinegars. Its brew technology has been listed in national non-material cultural heritage. And it is the location product of Shanxi. The xunpei technology is the important and unique process of Shanxi aged vinegar, and is the quintessence in its produce process. The Maillard reaction accorded in xunpei could give Shanxi aged vinegar beautiful color and aroma flavour. Hence, study the flavour of the material gained from xunpei process, or study the aroma components produced during xunpei, it is benefit to improvement of xunpei technology of Shanxi vinegar. And it is also important to evaluate the quality of xunpei produced from mechanization xunpei technology. The contents and conclusion of this study as follows:(1) The headspace solid-phase microextraction (HS-SPME) and gas chromatographic mass spectrometry (GC/MS) methods was adopted to analyze aroma components in Shanxi aged vinegar. The different SPME fibers, capillary column of gas chromatography and warming conditions were screened. The optimized conditions were 75 μm Carboxen/PDMS fiber, RXT-WAX column and warming condition 2 (the start warm was 32℃, then rise to 120℃ at speed of 3℃/min, then rise to 250℃ at speed of 10℃/min, maintain 10min). Forty aroma components including seven acids, two aldehyde, two alcohol, five ester, five ketone and thirteen heterocycle components had been identified in ten years vinegar at the optimized conditions.(2) Dynamic change of aroma components in traditional xunpei process of Shanxi aged vinegar had been analyzed. The results showed that the main aroma of xunpei in Shanxi aged vinegar were eater, acid, heterocycle, alcohol and aldehyde components. The types of aroma components were increased during xunpei process (1 to 5days). The types of aroma components increased from 27 to 35 types during 1 to 4 days of xunpei process. At the day of xunpei 4 and 5, both the types of aroma components were 35. The acid and ester content were decreased during xunpei process. The lost of ester and acid content was 20% and 46% at 5 days xunpei, respectively. The content of heterocycle was increased during xunpei process (1 to 5 days). The total contents of heterocycle at 4 and 5 days xunpei were 21.3 and 22.5 times of the 0 day xunpei, respectively. Hence, considering the quality of xunpei aroma and effect of production, the 4 days was the best time for traditional xunpei.(3) Comparison analysis the quality of aroma between mechanization (100℃,24h) and traditional (80-90℃, four days) xunpei technology, the HS-SPME and GC/MS was adopted and the character aroma components as the evaluated index. Compare to traditional xunpei, the total content of acid, ester, heterocycle, aldehyd and alcohol increased 42.5%,1.5 times,21.7%,3.7% and 18.5%, respectively. The content of tetramethylpyrazin in mechanization xunpei increased three times compared to traditional xunpei. Theses results suggested that the aroma quality of mechanization xunpei better to traditional xunpei, the mechanization xunpei is benefit to enhance the content of character aroma components and improve flavour feature and healthcare function in xunpei, this technology is worth of development.