LC-MS-based metabolomics revealed the influence of chemical profile on sensory and color characterization of Yunnan Pu-erh tea products: Lao Man Er and Mao Er Duo.

BACKGROUND

Pu-erh tea products, particularly Lao Man Er (LME) and Mao Er Duo (MED) produced from the large leaf variety (Camellia sinensis var. assamica) in Yunnan province, show distinctive sensory profiles and complex chemical compositions. This study conducts sensory evaluation, metabolomics, and instrumental colorimetry to analyze the chemical and functional characteristics of these teas.

RESULTS

Sensory evaluation (0-10 intensity score) shows clear differences between the two teas. LME records higher bitterness (5.58 ± 1.14) and astringency (5.71 ± 0.66), whereas MED demonstrates a significantly stronger sweet aftertaste (1.07 ± 0.27). Colorimetric analysis also reflects these distinctions. LME exhibits greater lightness (L* = 96.12 ± 0.68) and yellowness (b* = 17.21 ± 1.46), while MED produces a darker, more intense infusion and demonstrated more stable antioxidant activity. These differences were associated with variations in catechin composition: MED contains higher levels of galloylated catechins ((-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG),(-)-gallocatechin gallate (GCG)), which degrade into non-galloylated contributing to sweetness, while LME has higher contents of (-)-epicatechin (EC) and (+)-gallocatechin (GC) compounds associated with bitterness and astringency. Bitterness and astringency were positively correlated with caffeine, EGCG, and non-galloylated catechins, while lightness correlated with flavonol glycosides and yellowness with chlorogenic acid. Both teas inhibited α-amylase and α-glucosidase, with MED showing slightly stronger α-amylase inhibition.

CONCLUSION

This study demonstrates that distinct metabolite patterns, particularly in catechins and pigments govern the sensory and functional characteristics of Pu-erh tea. These insights not only deepen understanding of tea quality formation but also provide a scientific basis for improving manufacturing control, enhancing consistency, and designing market-targeted products. © 2025 Society of Chemical Industry.