Pear polyphenol oxidase enhances theaflavins in green tea soup through the enzymatic oxidation reaction

Abstract

Polyphenol oxidase (PPO) is a necessary medium for converting catechins into theaflavins in tea. This study aimed to provide an efficient and cost-effective method for the purpose of developing a tea beverage rich in four main theaflavins (TFs) by optimizing the key factors affecting the enzymatic oxidation reaction to produce TFs. Autumn green tea (AT) soup was mixed with pear PPO crude enzyme solution and then reacted for different time at varying reaction temperatures, pH, ratios of tea soup to crude enzyme solution, and ratios of tea to water. The content of TFs in tea beverage was monitored by UPLC-Q-Orbitrap-MS/MS to select the optimal process parameters to produce the maximum TFs. The TFs content after the reaction increased 968.49 times compared with that before the reaction. The results showed that the use of the enzymatic oxidation reaction of pear PPO crude enzyme solution to improve the TFs in AT soup was efficient. This method helped regulate the strong bitter and astringent taste sensation in AT, and it is unnecessary to purify the PPO enzyme source. This method is expected to be a breakthrough to use AT to produce high TFs tea beverages in a cost-effective way with high value.

Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) to reveal the flavor characteristics of ripened Pu-erh tea by co-fermentation

“…As a beverage with health function, tea is widely welcomed. According to the degree of fermentation, tea is generally divided into green tea, yellow tea, white tea, oolong tea, black tea, and dark tea ( 1 , 2 ). Ripened Pu-erh tea is one of the most popular dark teas ( 3 ).…”