酵母抽提物添加时间对酱油风味的影响

该研究采用电子鼻技术和气相色谱-质谱联用技术（GC-MS）对未添加酵母抽提物（YE）酿造酱油（编号为YE0），发酵前期（入缸）、中期（发酵30 d）和后期（发酵60 d）添加YE酿造的酱油（编号为YE1、YE2和YE3）中的挥发性香气成分进行分析。结果显示，四种样品通过GC-MS共检测到49种挥发性风味化合物，YE1中酯类、醛类、醇类和酮类的含量最高，这些物质有利于丰富酱油中的麦芽香、焦糖香、花香和果香，可使酱油风味更加饱满和谐，其中，3-甲硫基丙醛、5-乙基-4-羟基-2-甲基-3（2H）-呋喃酮（HEMF）是酱油典型香气的主要贡献物者；随着中、后期添加YE，酯类、醛类、醇类和酮类物质含量呈现下降趋势。主成分分析（PCA）结果表明，与在酱油发酵前期添加YE相比，在发酵中期和后期添加YE对酱油的风味影响不明显。

Effect of addition time of yeast extract on soy sauce flavor

In this study, the aroma components of soy sauces without yeast extract (YE) addition (YE0) and with yeast extract addition in the early fermentation stage (in cylinder) (YE1), middle fermentation stage (30 d) (YE2) and late fermentation stage (60 d) (YE3) were analyzed by electronic nose technology and GC-MS. The results showed that a total of 49 volatile flavor compounds were detected by GC-MS in the four samples. The content of esters, aldehydes, alcohols and ketones were the highest in YE1, these compounds were beneficial to enrich the malt, caramel, floral and fruity aromas of soy sauce, making the soy sauce flavor more full and harmonious, among them, 3-methyl thiopropionaldehyde and 5-ethyl-4-hydroxy- 2-methyl-3(2H)-furanone (HEMF) were the main contributors to the typical aroma of soy sauce. With the yeast extract addition in the middle and late fermentation stages, the content of esters, aldehydes, alcohols and ketones showed a downward trend. The results of principal component analysis (PCA) showed that, compared with yeast extract addition in the early fermentation stage of soy sauce, yeast extract addition in the middle and late fermentation stages had no obvious effect on the soy sauce flavor.