冠突散囊菌发酵对茶汤香气成分的影响

为探讨冠突散囊菌(Eurotium cristatum)发酵对茶叶提取液香气成分的影响,利用冠突散囊菌对中低档绿茶和红茶提取液进行发酵,采用顶空固相微萃取结合气相色谱-质谱法分别检测审评用样品以及提取、灭菌和发酵后样品的香气成分,分析香气成分的变化规律。结果表明,绿茶与红茶提取液经冠突散囊菌发酵新产生苯甲酸甲酯、异佛尔酮、对甲氧基苯乙烯、对乙基苯甲醛、香叶酸甲酯、3,4-二甲基苯甲酸甲酯6种化合物。同时,绿茶茶汤经冠突散囊菌发酵后,芳樟醇、芳樟醇氧化物I、芳樟醇氧化物II、苯乙酸甲酯、α-松油醇、反-2-癸烯醛和α-紫罗酮分别增长了1.30、2.15、2.04、0.29、3.18、0.10倍和2.08倍,且香气种类与含量均上升。但红茶茶汤经冠突散囊菌发酵后大部分香气物质含量下降,其中苯乙醇、反-2-壬烯醛、2-苯基巴豆醛、顺柠檬醛、4-甲基-2-苯基-2-戊烯醛、月桂醛、肉豆蔻醛等未检出,表明冠突散囊菌发酵红茶会带来香气总量的损耗,与红茶相比,低档绿茶更适合使用冠突散囊菌开发发酵型饮料。

Effect of Fermentation with Eurotium cristatum on Aroma Components of Tea Infusions

The aroma components of green tea and black tea infusions were quantified by headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) before and after fermentation with Eurotium cristatum. It was found that benzoic acid methyl ester, isophorone, methoxy styrene, ethyl benzene, formaldehyde, sweet folic acid methyl ester, and 3,4-dimethyl methyl benzoic acid were detected in the fermented tea infusions, but not in the fresh ones. In the green tea infusion, the concentrations of linalool, linalool oxide I, linalool oxide II, methyl phenylacetate, α-terpineol, trans-2-decylolefine aldehyde, and α-ionone were elevated by 2.30, 3.15, 3.04, 1.29, 4.18, 1.10 and 3.08, respectively after the fermentation, and the number and amount of aroma components increased similarly. In contrast, for the black tea infusion, the majority of the aroma compounds decreased and phenethyl alcohol, trans-2-nonenal, 2-phenylcrotonaldehyde, cis-citral, 4-methyl-2-phenyl-2-pentenal, lauraldehyde and tetradecanal were undetectable after the fermentation, indicating a loss of the total amount of aroma components. Compared to black tea, low-end green tea was more suitable for the processing of fermented beverage with E. cristatum.