Effects of wine yeast in fermenting green tea

Fermenting green tea with Saccharomyces cerevisiae—the yeast used in fermentation for winemaking—produced a novel green tea with enhanced aromas and the same important health benefits that green tea is known for, according to a team of researchers from Singapore and China. The study was published in the Journal of Food Science.

The flavor of tea can be changed through enzymatic and microbiological processes or by adding flavorings. For example, the researchers point out that pu-er tea is produced through microbial fermentation with Aspergillus niger, which helps to produce key volatiles responsible for the tea’s characteristic aroma and flavor. The use of wine yeasts like S. cerevisiae has not been investigated, wrote the researchers. Hence, they set out to ferment green tea using the yeast to learn how yeast metabolism may affect bioactives and flavor and aroma compounds.

The results showed that fermenting green tea with S. cerevisiae did indeed affect key components of the green tea, most notably certain aroma compounds such as linalool and 2-phenylethanol, which gave the tea strong floral and fruity notes. On the other hand, compounds such as caffeine, theobromine, and theophylline were significantly reduced. Importantly, the antioxidant capacity did not change.