Reveal the influence mechanism of different storage containers on the flavor of ripe Pu-erh tea based molecular sensory science

Abstract

The storage was a critical factor influencing the quality of ripe Pu-erh tea (RPT). However, research on the influence of different storage methods on the quality of RPT has been limited, primarily due to constraints related to environment and time. Utilizing sensory evaluation, gas chromatography combined with quadrupole time-of-flight mass spectrometry (GC-QTOFMS) and High Performance Liquid Chromatography (HPLC), we investigated the chemical composition differences of RPT stored in its original packaging and in four different container types (pottery jar storage, iron pot storage, carton storage, and wooden box storage). We found that container storage significantly enhanced the sweet after taste and stale aroma profile. A total of 101 volatile metabolites were identified, with 1,2,4-trimethoxybenzene emerging as the primary differential metabolite distinguishing container storage from original storage. Analysis of non-volatile metabolites revealed that container storage was conducive to an increase in sweet-tasting compounds such as Glycine and Threonine, and a reduction in bitter and astringent compounds such as epigallocatechin gallate. Furthermore, correlation analysis established that 1,2,4-trimethoxybenzene exhibited the strongest positive correlation with the stale aroma, while safranal was closely associated with an increase in jujube-like aroma. These findings provide a theoretical basis for optimizing the storage conditions of RPT.