# Enhancement of flavor components of oolong tea and dark tea based on graphene heating film

## TL;DR

This study shows that using graphene heating film during tea processing can enhance the flavor of oolong and dark tea by altering specific compounds.

## Contribution

The study introduces graphene heating film as a novel method for tea re-tempering and identifies optimal parameters for flavor enhancement.

## Key findings

- Graphene heating increases woody and fruity compounds in oolong tea at lower temperatures.
- Floral compounds in dark tea increase with higher temperature and longer heating times.
- The ratio of ester to non-ester catechins in tea changes with graphene heating.

## Abstract

Reheating is crucial for improving tea quality, and graphene heating film provides a stable, uniform heating surface. This study used graphene heating film to heat oolong and dark tea at medium (M, 65 °C) and high (H, 75 °C) temperatures for 10, 20, and 30 min to assess the impact on flavor compounds. The results showed that the optimal parameters are as follows: the content of ester catechins decreased, the content of non-ester catechins increased, and the concentrations of woody and fruity compounds (Cedrol, Limonene, trans-Isoeugenol, Indole) significantly increased at M10 or H10 in oolong tea. The ester catechin content decreased at H20, the non-ester catechin content increased at M20, and the concentration of Floral compounds (trans-β-ionone) increased at H30 in dark tea. This study explores the potential of graphene heating film in tea processing, offering a theoretical basis for new technology in tea flavor enhancement.

•Graphene heating film can be applied to tea refire.•There are differences in the re-tempering parameters adapted to different teas.•The application of graphene heating film has changed the ratio of ester to non-ester catechins in tea.•The application of graphene heating film improves the floral and fruity aroma of tea.

Graphene heating film can be applied to tea refire.

There are differences in the re-tempering parameters adapted to different teas.

The application of graphene heating film has changed the ratio of ester to non-ester catechins in tea.

The application of graphene heating film improves the floral and fruity aroma of tea.