Physicochemical analysis, sensorial evaluation, astringent component identification and aroma-active compounds of herbaceous Peony (Paeonia lactiflora Pall) black tea

The fermentation of herbaceous peony black tea by enzyme is beneficial to improve the flavor quality. This work aimed to investigate the influence of withering and fermentation on the taste and aroma of herbaceous peony black tea by combining physical and chemical analysis, sensory evaluation, LC-QQQ and GC-QTOF. Physicochemical analysis and sensory evaluation determined that a withering degree of 30, fermentation time of 4 h and fermentation temperature of 28 °C improved the quality of herbaceous peony black tea. Moreover, LC-QQQ combined with sensory evaluation results showed that polyphenols (gallic acid and methyl gallate, catechin, (-)-epicatechin gallate, and naringenin) and monoterpenes (paeoniflorin and albiflorin) were significantly correlated with the astringency of herbaceous peony black tea (P < 0.05) and that fermentation could effectively reduce the astringency of herbaceous peony black tea. GC-QTOF combined with OPLS-DA (VIP > 1) identified 28 volatile components as key herbaceous peony black tea compounds. Compared with unfermented tea, the volatile components and contents were significantly increased by fermentation, and phenylethyl alcohol, 5-methylfurfural, cuminaldehyde, 1-(furan-2-yl) ethanone and o-cymene were formed. This study provides a theoretical basis and technical guidance for the comprehensive utilization and green development of herbaceous peony petal tea.