Effect of inoculation with Penicillium chrysogenum on chemical components and fungal communities in fermentation of Pu-erh tea

A comprehensive review of polyphenol oxidase in tea (Camellia sinensis): Physiological characteristics, oxidation manufacturing, and biosynthesis of functional constituents

“…Compared to peroxidases and glucosidase, PPO plays a significant role in the catalysis of flavones during tea manufacturing (Guo et al., 2021). Thus, the utilization of PPO in tea leaves with varying degrees of treatment increases the diversity of tea products while improving sensory quality and increasing the sensory quality, yield, and purity of functional constituents of tea, which has significantly benefited the global tea beverage sector (Liu et al., 2021). With the growth of business and technological advancements, PPO technology has been completely integrated into tea manufacturing and has significant potential for application in tea processing.…”

“…The PPO produced by fungi is an important enzyme that catalyzes the oxidation of tea polyphenols during tea fermentation (Lee et al., 2015; Yabuki et al., 2017). At the same time, because mushroom‐derived tyrosinase preferentially oxidizes catechol rather than pyrogallol catechin and oxidizes EGCG to the ester‐type catechin gallic acid, it is more effective than crude tea PPO for the synthesis of TFs and their derivatives (Liu et al., 2021). The synthesis of TFs catalyzed by PPO from fungal strains has been reported in many studies, and genetic engineering technology is used to clone the PPO gene and insert it into cells.…”

“…Strains are injected into stacked raw tea in moderate humidity and temperature environments to improve the tea manufacturing process. Under conditions of adequate PPO activity, the primary functional constituents, such as polyphenols, are completely oxidized, providing a favorable character to the tea throughout this process (Liu et al., 2021). Because the PPO catalytic reaction is influenced by substrate type, temperature, pH value, and other factors, identifying the prevailing strains that produce PPO with high efficiency and obtaining a better understanding of the enzymatic transformation process of tea compounds is beneficial for improving the sensory quality of tea products and the formation of tea functional constituents using endogenous or exogenous enzymes during tea manufacturing, which have wide prospects in the field of deep processing and general utilization of tea.…”

“…As a result, more research on the oxidation mechanism of catechins in tea is needed, which has broad application potential in the area of deep tea processing. Currently, preserving PPO activity during fermented tea processing, optimizing innovative PPO technology, increasing the yield of oxidation polymerization products, developing methods for their efficient isolation and purification, and promoting their application in the health field are all topics that require further study in the tea industry (Liu et al., 2021).…”

Interaction and Metabolic Function of Microbiota during Tibetan Tea Fermentation through Bioaugmentation with Aspergillus niger

“…increased the content of biohydrogen [17]. Penicillium chrysogenum, through cooperation with other fungal species, changed the chemical composition and improved the sensory quality of Pu-erh tea (a kind of dark tea) during the bioaugmented fermentation stage [18]. Moreover, the identification of appropriate microorganisms plays a vital role in the BF of dark tea.…”