Variation in major phenolic compounds and quality potential of CTC black tea elicited by Saccharomyces cercevisiae and its correlation with antioxidant potential

•Effect of yeast inoculation on black tea metabolic changes and quality was revealed.•EGCG and caffeine level increased initially but reduced with prolonged treatment.•Increased (+)-catechin, EC and gallic acid reflect augmentation in TPC and TFC.•Yeast interaction improves made tea quality constituents such as TF, TR and TLC.•This method proves for improving quality and antioxidant potential of CTC black tea.

Changes in phenolic compounds along with quality parameters of CTC (Crush, Tear, Curl) black tea (BT) during yeast fermentation was revealed. The level of epigallocatechin-3-gallate (EGCG) and caffeine content increased at 12 h but prolonged period of treatment decreased their levels. Due to the changes in (+)-catechin, epicatechin (EC) and gallic acid content the level of total phenolic contents increased at 24 h. These changes reflected in quality constituents such as theaflavin (TF) and thearubigin (TR) contents of BT increased with 24 h of yeast interaction. Prolonged incubation time reduced the liquor brightness (LB) but increased the level of total liquor colour (TLC). The improvement in phenolic content resulted in high antioxidant activity in samples treated with yeast for a period of 24 h. Applying this method can bring forth improvement in product quality and antioxidant potentiality of CTC black tea.