Changes in the Flavor Quality of Flower and Fruit Scented Black Tea Stored at Room Temperature

To explore the effect of room temperature storage on the flavor quality and biochemical composition of flower and fruit scented black tea, this study compared the sensory flavor quality of flower and fruit scented black tea produced in the years 2019, 2020, 2021 and 2022 and stored at room temperature, and it detected volatile and non-volatile compounds in the tea by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and ultraperformance liquid chromatography coupled to orbitrap high resolution mass spectrometry (UPLC-Orbitrap-MS). The results showed that the sensory quality of flower and fruit scented black tea was significantly affected by storage at room temperature, and the tea lost its floral and fruity aroma characteristics after three years of storage at room temperature; its quality characteristic was mature sour taste. The tea samples were divided into four groups of age by principal component analysis (PCA) and hierarchical cluster analysis (HCA). Totally 15 volatile differential compounds such as linalool, cis-β-ocimene, and hexanoic acid (VIP > 1 and P < 0.05), and 154 non-volatile differential compounds such as theanine, epicatechin, and gluconic acid (VIP > 2 and P < 0.05) were selected by partial least squares discriminant analysis (PLS-DA) and one-way analysis of variance (ANOVA). The content of volatile compounds such as linalool, hexanal, cis-β-ocimene, and 2-pentylfuran decreased with increasing storage time, while the contents of hexanoic acid, dihydroactinidolide 1-ethyl-2-formyl-1H-pyrrole, and β-ionone increased. The contents of non-volatile compounds such as most amino acids, nucleotides, sugars, tea polyphenols tended to decrease with increasing storage time, while the contents of organic acids and lipids showed an increasing trend. The results obtained from this study can provide a scientific basis for elucidating the quality changes of flower and fruit scented black tea during storage and help guide its rational storage and scientific consumption.