Innovative manufacturing process to enhance the taste and color of Ancha tea: A comprehensive analysis using sensory evaluation, chemometrics, and metabolomics

Abstract

Ancha tea (ACT) is a type of dark tea processed through dew wetting. However, the unpredictability and instability of the dew wetting process limits the efficiency and quality of production. To address this issue, we used the same primary tea to produce no dew wetting ACT (DDW), dew wetting ACT (DW), and three new process ACT (SF5, SF8, and SF10). The results showed that SF8 had the best quality among all the samples; moreover, the color and taste of DW were superior to DDW. Using LC-Orbitrap-MS analysis, we identified 48 differential metabolites. Through partial least squares regression (PLSR) and correlation analysis, we found that five components, including quercetin 3-galactoside, chlorogenic acid, and kaempferol, contributed the most to the infusion color, while fifteen components were identified as the major contributors to taste. Further metabolic pathway analysis revealed that the new process promoted the degradation of epigallocatechin gallate and quercetin 3-galactoside and increased the transformation of D-glucose and L-pyroglutamic acid, possibly through the moist-heat effect, resulting in improved taste. These transformations occur at a lower rate during dew wetting. This study proposes a new process and compares its effects and mechanisms on the quality of ACT with that produced using dew wetting process. The findings provide a solution to the problems of low efficiency, unstable product quality, and poorer quality of fresh tea in ACT production, and promotes standardized and high-quality production of ACT.