山西老陈醋酿造过程四甲基吡嗪形成规律及稳定性研究

The formation and stability of tetramethylpyrazine in the brewing process of Shanxi aged vinegar

四甲基吡嗪是山西老陈醋中重要的风味与功能物质之一,该文对山西老陈醋整个酿造过程中四甲基吡嗪变化规律进行了分析。醋酸发酵和熏醅阶段是其含量增加的主要阶段。进一步分析了乙偶姻、双乙酰、铵以及16种氨基酸等四甲基吡嗪主要前体化合物在醋酸发酵阶段的变化规律,重点分析了温度对四甲基吡嗪生成及其稳定性的影响。结果表明,熏醅过程四甲基吡嗪处于生成和降解的动态平衡,高温和乙酸是四甲基吡嗪降解的主要原因。95℃熏醅3 d时四甲基吡嗪含量与85℃和105℃条件下熏醅相比分别提高30%和17%,总酯含量提高9%和10%,并且增加了酯类、酮类、醛类和杂环类风味物质相对含量,总酸、还原糖和氨基态氮等指标无显著差异,说明95℃熏醅温度更有利于四甲基吡嗪等风味物质的积累。

Tetramethylpyrazine(TMP)is one of the important flavor and functional substances in Shanxi aged vinegar(SAV).In this paper,the formation of TMP in the whole brewing process of SAV was analyzed.The results showed that TMP mainly accumulated in the stages of acetic acid fermentation and fumigation.Therefore,the changes of precursors for TMP formation,including acetoin,diacetyl,ammonium nitrogen,and amino acids,were analyzed.In particular,the effect of temperature on the formation and stability of TMP was investigated.The results showed that TMP was in a dynamic balance between formation and degradation in the fumigation process,which was mainly affected by temperature and acidity.When compared with those fumigated at 85 and 105℃,the TMP concentration in Cupei fumigated at 95℃for 3 d increased by 30%and 17%,and the total ester concentration increased by 9%and 10%,respectively.The relative concentrations of esters,ketones,aldehydes,and heterocyclic flavor substances were also increased.There were no significant differences in total acid,reducing sugar,and amino nitrogen when fumigated under there different temperatures.Those results indicated that fumigation under 95℃contributed to the accumulation of TMP and the other flavor compounds.