Active pharmaceutical ingredient-correlated wavelength selection of UV-vis spectroscopy for the rapid quality assessment of red yeast Rice

Red yeast rice (RYR) is a traditional fermented product produced by cultivating rice with the filamentous fungus Monascus purpureus. It has been widely utilized in East Asia both as a natural food colorant and as a lipid-lowering herb. Rapid quality assessment is critical for the production, transaction and utilization of RYR. Since empirical evidence suggests that the chromatic properties of RYR correlate closely with its quality, UV-Vis spectrophotometric analysis at specific wavelengths has become a common proxy for rapid quality evaluation of RYR. However, there has been no universal consensus on the selection of these wavelengths. In this study, an active pharmaceutical ingredient (API)-correlated wavelength selection strategy was proposed to ensure analytical accuracy and biological interpretability of the selected UV-Vis wavelengths for the rapid quality assessment of RYR. Integrated bioinformatic analysis confirmed that Monascus Pigments (e.g., monascin, rubropunctatin, rubropunctamine) and monacolin K were the dominant pharmacologically active components of RYR. Notably, both the profiles and concentrations of these Pigments varied significantly across RYR samples from different manufacturers. Through systematic correlation analysis and principal component analysis (PCA), three optimal characteristic wavelengths were identified: 570 nm (associated with monascin and rubropunctamine), 450 nm (associated with rubropunctatin), and 230 nm (roughly associated with monacolin K). This work not only establishes chemically rational, API-informed UV-Vis wavelengths for standardized RYR quality assessment, but also offers a transferable methodological framework for the rapid quality control of Other pigment-rich fermented products.

Monacolin; Monascus pigment; Quality assessment; Red yeast rice; UV–vis spectroscopy.