Wang Rui, Sun Jingcan, Lassabliere Benjamin, Yu Bin, Liu Shao Quan
Department of Food Science & Technology, National University of Singapore, Science Drive 3, Singapore, 117543, Singapore.
Mane SEA PTE LTD, Biopolis Drive 3, 138623, Singapore.
Food Microbiol. 2020 Dec;92:103609. doi: 10.1016/j.fm.2020.103609. Epub 2020 Jul 30.
The fermentation characteristics of non-Saccharomyces yeasts (Pichia kluyveri FrootZen, Torulaspora delbrueckii Prelude, Williopsis saturnus var. mrakii NCYC2251 and Torulaspora delbrueckii Biodiva) were evaluated in green tea slurry fermentation. Each yeast showed different fermentation performances: strains Prelude and Biodiva utilized sucrose faster than the other two yeasts; strain NCYC2251 was the only species that metabolized xylose. Strain FrootZen increased the caffeine content significantly and strain Prelude showed the opposite trend, both at a statistical level, while theanine contents in four samples were relatively stable. Biodiva and FrootZen significantly improved polyphenols content and the oxygen radical absorbance capacity of fermented teas. Some endogenous volatiles such as ketones, lactones and aldehydes decreased to lower or undetected levels, but one of the key tea aroma compounds methyl salicylate increased by 34-fold and 100-fold in P. kluyveri and W. saturnus samples respectively. Therefore, green tea fermentation by appropriate non-Saccharomyces yeasts can enhance its antioxidant capacity and alter the aroma compound profile.
在绿茶浆发酵过程中评估了非酿酒酵母（克鲁维毕赤酵母FrootZen、戴尔布有孢圆酵母Prelude、土星威克酵母mrakii变种NCYC2251和戴尔布有孢圆酵母Biodiva）的发酵特性。每种酵母都表现出不同的发酵性能：Prelude和Biodiva菌株利用蔗糖的速度比其他两种酵母更快；NCYC2251菌株是唯一能代谢木糖的菌种。在统计学水平上，FrootZen菌株显著增加了咖啡因含量，而Prelude菌株则呈现相反趋势，同时四个样品中的茶氨酸含量相对稳定。Biodiva和FrootZen显著提高了发酵茶的多酚含量和氧自由基吸收能力。一些内源性挥发物如酮类、内酯类和醛类降低到较低水平或未检测到，但关键的茶香气化合物之一水杨酸甲酯在克鲁维毕赤酵母和土星威克酵母样品中分别增加了34倍和100倍。因此，用合适的非酿酒酵母进行绿茶发酵可以提高其抗氧化能力并改变香气化合物谱。
