Exploring seasonal differences in taste and nonvolatiles of Lu'an Guapian tea and perceptual interactions between odorants and EGCG via multi-sensory analysis and metabolomics.

Lu'an Guapian (LAGP) tea, a traditional Chinese green tea exclusively produced from mature leaves without buds or stems, is known for its mellow taste and distinct appearance. Subjective (sensory evaluation) and objective assessment (colorimeter and E-tongue) were conducted to provide a deeper insight into the differences between LAGP made from summer and autumn leaves and spring leaves. A total of 52 key differential metabolites were screened by metabolomics. Catechins and flavonoids, especially flavonol glycosides, exhibited significant seasonal variation. Pathway enrichment analysis indicated that flavonoid biosynthesis was the key factor that caused the quality changes of LAGP tea in different seasons. Additionally, preliminary explorations revealed that appropriate addition of odorants, especially hexanal (12.0-14.4 μg/L) and (Z)-3-hexen-1-ol (4.88-5.85 μg/L), could effectively mask the bitterness of EGCG and improve sensory acceptability. These findings provide theoretical insights into the seasonal effects of LAGP tea and guide the optimization of optimization of summer-autumn tea production.