Alternative pathway implicated as an influencing factor in the synthesis of theaflavin

Abstract

The principal pigments present in black tea, theaflavins, have been indicated to be of potential clinical significance in various fields of research which has been hampered by the very low levels of theaflavins from black tea extractions, being the original method employed to acquire theaflavins. Forelle pear (44 µM Theaflavin/g dry weight/hr) and Yacon leaf (65 µM Theaflavin/g dry weight/hr) homogenates were tested for their theaflavin synthesis capacity and found to have a larger theaflavin synthesis capacity than a green tea leaf homogenate (26 µM Theaflavin/g dry weight/hr) based upon the flavognost method. In an incubation system of green tea leaf extract utilizing endogenous enzymes present in Forelle pear and Yacon homogenates to synthesise theaflavin, the formation of an unknown peak (m/z 563.1349; (23.95) 5 ; C 26 H 28 O 14 ) was detected by mass spectrometry with a molecular mass similar to theaflavin. This is in contrast to theaflavin being solely synthesised in an in vitro model incubation system using isolated catechins and purified Forelle pear polyphenol oxidase. The preferential formation of the unknown compound could explain the low levels of theaflavins in black tea.

Improving Theaflavin-3,3′-digallate Production Efficiency Optimization by Transition State Conformation of Polyphenol Oxidase

“…PPOs from snow lotus fruits have also been used to oxidize catechins to form theaflavins. The final estimate of theaflavins in the reaction system was 65 µM dry weight/h [28]. Under the catalysis of the optimum mutant BmTyr V218A/R209S , the titer of TFDG reached 960.36 mg/L with 44.22% conversion, which was 6.35-fold higher than that of the WT.…”

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

“…PPO widely exists in fresh tea leaves and other plants. Plant‐derived PPO, including tea leaves, pears, apples, loquats, blueberries, bananas, sweet potatoes, and mushrooms ( Agaricus bisporus ), can produce TFs (Q. R. Li et al, 2018; Takashi et al, 2002; Westhuizen et al, 2015; Zeng et al, 2019). Compared with other plant‐derived PPOs, pear PPO has stronger ability to catalyze the synthesis of TFs and is an excellent enzyme source for the synthesis of TFs with low utilization cost.…”