LED spectral tailoring directs flavor metabolites during white tea withering

Withering is a key step in the formation of white tea quality. However, traditional withering relies on weather conditions and lacks spectral control, resulting in inconsistent flavor characteristics. This study utilized LED spectra 400–700 nm white (W), 630 nm red (R), 630 nm red–450 nm blue (RB 1:1), 630 nm red–520 nm green light (RG 1:1), and indoor natural light (CK) withering. The effects of LED light spectrum withering on white tea flavor metabolites were investigated by integrating molecular sensory science and metabolomics technology. Regarding taste, R enhanced perceived sweetness by increasing the levels of sweet amino acids, while RB promoted umami, significantly associated with elevated theanine content. LC-Orbitrap-MS analysis identified 63 metabolites, revealing that catechins, amino acids, and organic acids were upregulated under four LED spectra, whereas flavonoids were downregulated. For aroma, all LED treatments reduced green notes. R specifically enhanced fruity notes, while W intensified floral and sweet characteristics. Among the 95 volatile compounds identified, 8 key aromatic compounds regulated by light spectra were confirmed. This study establishes the first metabolite-level evidence for LED spectral regulation of key flavor compounds during white tea withering, linking spectral quality to targeted shifts in taste and aroma metabolites. • Use of LED lights with different wavelengths in the withering process of white tea. • The sensory quality of different LED withered white tea varied significantly. • LED withering increases the concentration of volatile metabolites in white tea.