Effect of Fermentation Conditions and Plucking Standards of Tea Leaves on the Chemical Components and Sensory Quality of Fermented Juice

Abstract

e effects of fermentation conditions (temperature, time, and pH) and plucking standards (one leaf and a bud to four leaves and a bud) on the chemical components and sensory quality of the fermented juices processed from crushed fresh tea leaves were investigated. e results showed that optimum fermentation conditions that resulted in fermented juices of the best sensory quality and the highest content of TFs were a temperature of 35°C, time duration of 75 min, and pH 5.1. e fermented juices processed from new shoots with three leaves and a bud or four leaves and a bud afforded high overall acceptability and TF concentration. ese differences arise because tea leaves with different plucking standards have different catechin content and enzyme activities. Fermented tea juice possessed higher concentrations of chemical components such as soluble solids, amino acids, and TFs and exhibited better sensory quality as compared to black tea infusion. e TF concentrations decreased as the pH of the fermenting juice increased, and the fermented juice showed the best overall acceptability. ese results provide essential information for the improvement of the processing of black tea beverage by suggesting fermentation of fresh tea leaves as a better alternative to their infusion.

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“…During pile fermentation, the tea leaves are exposed to microbes in a high-humidity environment. Many components in tea leaves are degraded, oxidized, transformed and/or polymerized [5,6,7]. The alteration of these compounds affects the smell, taste, color and health-benefits of tea [8].…”

Effect of fermentation time and temperature on the of polyphenol compounds change of different Congou black tea

“…Fermentation time and temperature are the most important factors affecting the quality of Congou black tea (Yu et al, 2015). With the extension of fermentation time, catechins are continuously depleted to form TFs, TRs, TBs, and MAFs (Hua, Xu, et al, 2021;Tang et al, 2018). The fermentation temperature affects the quality of black tea by changing the activities of PPO and POD, with low temperatures resulting in a slower transformation of polyphenols because of lower enzyme activity; high temperatures lead to excessive oxidation of polyphenols and formation of high molecular weight polymers (Wu et al, 2018).…”

“…However, for XXH 21-3, the content of TF3G and TFDG increased, and TFs varied little from 2 to 4 hr of fermentation and then decreased, the levels of TF, TF3ʹG, and TRs were declined during processing; and (c) the content of TBs and MAFs-2 in the three Congou black teas increased gradually with increasing fermentation time from 2 to 8 hr. During the fermentation of Congou black tea, catechins, TFs, TRs, TBs, and MAFs-2 showed dynamic changes, catechins were oxidized to TFs in the initial stage, but as the prolongation of fermentation time, catechins are gradually exhausted, and then both TFs and small molecular weight TRs would be used as precursor substances condensed to form high molecular weight TRs, MAFs-2, and TBs (Hua, Xu, et al, 2021;Owuor & Obanda, 2001;Tang et al, 2018). Therefore, the concentration of the catechins substrate and activities of PPO and POD in fresh tea leaves may affect the changes in TFs, TRs, TBs, and MAFs-2.…”

Effects of β-Cyclodextrin and Sodium Ascorbate on the Chemical Compositions and Sensory Quality of Instant Green Tea Powder during Storage

“…Caffeine. Analysis of catechins and caffeine was carried out by the HPLC method according to the method that was described by Tang et al [13].…”