Search

• Green tea phenolic profile was changed massively by tyrosinase incubation. • Pre- & post-oxidation of green tea phenolics had similar anti-obesity effect. • Pre- & post-oxidation of green tea phenolics had similar effect on gut microbiota. • Anti-obesity effect of tea was associated with the alteration in gut microbiota. Green and black teas are regarded to possess therapeutic potential for the treatment of obesity, however it is not clear which tea performs better in body weight control. In this study, aiming to eliminate cultivar variation, green tea phenolics (GTP) were oxidized by tyrosinase to obtain oxidized tea phenolics (OTP). Thereafter, their anti-obesity effect on high-fat diet induced obese mice were compared. The results showed that despite their distinctive phenolic profiles, GTP and OTP exerted similar anti-obesity properties after 12 weeks of dietary intervention. Furthermore, cecal microbiota profiling exhibited comparable modulatory effects of GTP and OTP on multiple bacterial taxa, including Parabacteroides distasonis , Bifidobacterium , Prevotella , and Akkermansia muciniphila , which were strongly associated with obesity related indexes. Putative bacterial function profiling implicated that both GTP and OTP might regulate the lipid metabolism similarly. Collectively, the oxidation of GTP did not influence the anti-obesity and gut microbiota modulatory effects to any large extent. [ABSTRACT FROM AUTHOR]

• A novel approach to flavor tea while retaining antioxidant activity was addressed. • The fermented tea with W. cocos imparted a jasmine-like & citrus-like flavor. • Methy anthranilate, linalool & 2-phenylethanol were identified as key odorants. • Upscaling to bioreactor (2 L) was succesfully applied. • 80% of antioxidant activity of green tea was preserved after fermentation. In response to the increasing interest of western consumers in high antioxidant activity of green tea but their low acceptance of its green odor, we employed a new starter culture, Wolfiporia cocos to tune flavor of green tea infusion. After submerged fermentation for 17 h, W. cocos changed the characteristic green odor to an attractive floral, jasmine-like, and slightly citrus-like flavor while preserving most of in vitro antioxidant activity. By application of mSBSE-GC-MS-O combined with sensorial tests, the formed pleasant aroma was mainly attributed to methyl anthranilate (OAV 802), linalool (OAV 190), 2-phenylethanol (OAV 165), and geraniol (OAV 118). Concurrently, the catechin profile determined by UHPLC-MS showed diverse reduction rates (10–50%) for the individual catechins after fermentation. Nevertheless, up to 80% of in vitro antioxidant activity in DPPH assay was preserved. Overall, our findings provide an innovative approach to naturally flavor green tea while retaining the antioxidant activity. [ABSTRACT FROM AUTHOR]