棒状乳杆菌FZU63发酵对红茶汤风味品质改善的作用

乳酸菌发酵可赋予茶饮料独特的香气与滋味，且可改变其物质组成，产生益生因子等。目前，针对乳酸菌在不同发酵阶段对茶汤中风味物质形成影响的研究较少。本研究以从中国传统泡菜中筛选获得的棒状乳杆菌FZU63为发酵菌株，对不同发酵阶段红茶汤中的挥发性香气成分、还原糖、游离氨基酸、有机酸等含量的变化过程进行分析，并对发酵红茶汤的感官品质进行评价。结果表明，棒状乳杆菌FZU63以红茶汤中的葡萄糖、果糖、甘露糖和木糖作为发酵过程中的主要碳源物质。红茶汤经棒状乳杆菌FZU63发酵作用后，香气成分丰度显著增加，且主要香气组分结构发生改变，发酵红茶汤在花香、坚果香的基础上增添了水果香；此外，部分苦味氨基酸含量下降，甜味和鲜味氨基酸含量增加；并且，乳酸、苹果酸、柠檬酸等有机酸含量在发酵过程中呈现积累。同时，感官评定结果表明棒状乳杆菌FZU63发酵可改善红茶汤的感官品质，且在发酵48h后达到较优。本文系统分析了经棒状乳杆菌发酵不同阶段对红茶汤风味的影响，可为乳酸菌发酵茶饮料的品质控制与产业化应用提供理论参考。

Effect of Lactobacillus coryniformis FZU63 on the flavor quality of black tea beverage

The tea beverages will be endowed with distinct aroma and taste, as well as various biologically active compounds including probiotic factors, when fermented with lactic acid bacteria (LAB). However, at present, few studies on the dynamics of flavors in tea soup at different fermentation stages were conducted. In this study, the composition of monosaccharides, aromatic components, free amino acids, and organic acids were measured, when the black tea beverages were fermented with Lactobacillus coryniformis FZU63 which was isolated from Chinese traditional kimchi. The results indicated that monosaccharides including glucose, fructose, mannose and xylose in black tea beverages are the main carbon sources for fermentation. In addition, the abundance of aromatic compounds in black tea soup are increased significantly at different fermentation stages, which endow the fermented black tea soup with fruit aroma on the basis of flowery and nutty aroma. Moreover, some bitter amino acids are reduced, whereas the content of sweet and tasty amino acids is elevated. Furthermore, the levels of lactic acid, malic acid, citric acid and other organic acids are accumulated during the fermentation. Additionally, sensory evaluation displays that black tea beverage is acquired with comprehensive high-quality after being fermented for 48 h. This study provides a theoretical basis to steer and control the flavor formation and quality of the fermented tea beverages during LAB fermentation.