The effect of high hydrostatic pressure on taste substance distribution in fresh green tea leaves

ABSTRACT

High hydrostatic pressure (HHP) can be an alternative method to steaming to inhibit enzymatic fermentation in green tea making process. However, the effect of HHP treatment on green tea taste is not clear. Thus, this study aimed to determine the effect of HHP on substances associated with green tea taste. Fresh green tea leaves were immediately treated with HHP at 300, 500, or 700 MPa for 10, 30, or 60 min at 25°C. The concentration of free amino acids, catechins, and caffeine in HHP-treated samples was quantified by LC-MS. The taste intensity of the samples was detected by taste sensors. HHP resulted in a high accumulation of free amino acids in green tea leaves, which was likely due to proteolysis. In particular, theanine synthesis may have been promoted by an increase in the concentration of substrates during HHP. Compared to steaming, HHP enhanced umami richness, and inhibited bitterness and astringency.

KEYWORDS:

• Green tea
• taste substance
• free amino acid
• theanine
• high hydrostatic pressure

Acknowledgements

We would like to express our special thanks to ODUTSUMI EN, a green tea corporation in Saitama, Japan, for providing fresh green tea leaves.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by JSPS KAKENHI [grant number 15K14832, 17K00811, and 17K00812].