Su Wei-Ying, Gao Shu-Yi, Zhan Si-Jia, Wu Qi, Chen Gui-Mei, Han Jin-Zhi, Lv Xu-Cong, Rao Ping-Fan, Ni Li
Institute of Food Science and Technology, College of Biological Science and Engineering, Fuzhou University, Fuzhou, China.
Food Nutrition and Health Research Center, School of Advanced Manufacturing, Fuzhou University, Fuzhou, China.
Front Nutr. 2022 Apr 14;9:865991. doi: 10.3389/fnut.2022.865991. eCollection 2022.
Green tea has distinct astringency, bitter taste, and typical green flavor because of its post-harvest treatment without withering and enzymatic oxidation. Microbial fermentation has been identified as a promising strategy that could give green tea infusion a special taste flavor. This might be linked to the metabolic transformation ability of microorganisms. In this study, starter culture of edible mushroom (oyster mushroom) was used for submerged fermentation of green tea infusion in order to improve its flavor and taste quality. The volatile profile determined by headspace solid-phase microextraction, coupled with gas chromatography mass spectrometry, showed that the contents of ()-2-penten-1-ol and methyl heptadienone in green tea infusion were decreased significantly by the fermentation with the basidiomycete ( < 0.01), which would alleviate the herbal and grass flavor of green tea infusion to a certain extent. Meanwhile, the contents of linalool and geraniol were increased 9.3 and 11.3 times, respectively, whereas methyl salicylate was newly produced after fermentation by , endowing the fermented tea infusion with a pleasant flower and fruit aroma. In addition, the polyphenol profile was determined using high-performance liquid chromatography equipped with ion trap mass spectrometry, and the results indicated that the contents of most polyphenols in green tea infusion decreased significantly after fermentation by . The reduction of catechins and anthocyanins in fermented green tea infusion alleviated the astringency and bitterness. Moreover, the antioxidant activity of fermented green tea infusion was obviously decreased, especially the DPPH-free radical-scavenging ability and the ferric-reducing power. However, it is noteworthy that the ABTS-free radical scavenging ability was improved compared with the unfermented one, indicating that the increased tea pigments and volatile metabolites (such as linalool and geraniol) after fermentation with may also contribute to the antioxidant capacity of fermented green tea infusion. Overall, the innovative approach driven by -caju fermentation has achieved promising potential to manipulate the green tea flavor.
由于绿茶采后不经萎凋和酶促氧化处理，因而具有独特的涩味、苦味和典型的绿色风味。微生物发酵已被确认为一种有前景的策略，可为绿茶茶汤赋予特殊的风味。这可能与微生物的代谢转化能力有关。在本研究中，使用食用菌（平菇）的发酵剂对绿茶茶汤进行深层发酵，以改善其风味和品质。通过顶空固相微萃取结合气相色谱 - 质谱联用仪测定挥发性成分，结果表明，担子菌发酵后，绿茶茶汤中（）-2-戊烯 -1-醇和甲基庚二烯酮的含量显著降低（<0.01），这在一定程度上减轻了绿茶茶汤的草青味。同时，芳樟醇和香叶醇的含量分别增加了9.3倍和11.3倍，而发酵后新产生了水杨酸甲酯，赋予发酵后的茶汤宜人的花果香气。此外，使用配备离子阱质谱的高效液相色谱法测定多酚谱，结果表明，发酵后绿茶茶汤中大多数多酚的含量显著降低。发酵绿茶茶汤中儿茶素和花青素的减少减轻了涩味和苦味。此外，发酵绿茶茶汤的抗氧化活性明显降低，尤其是DPPH自由基清除能力和铁还原能力。然而，值得注意的是，与未发酵的茶汤相比，ABTS自由基清除能力有所提高，这表明发酵后增加的茶色素和挥发性代谢物（如芳樟醇和香叶醇）也可能有助于提高发酵绿茶茶汤的抗氧化能力。总体而言，由 - 卡朱发酵驱动的创新方法在调控绿茶风味方面具有可观的潜力。
