Investigation of processing duration on red ginseng quality utilizing delayed luminescence combined with chemometrics and immunomodulatory assessment

Red ginseng (RG) is a functional food with tonic benefits made by steaming ginseng. Its quality depends strongly on steaming duration, yet no standardized processing time exists. Therefore, rapidly, eco-friendly, and user-friendly analytical methods are needed to improve RG quality control. Delayed luminescence (DL) can reflect the internal changes caused by processing by detecting the photon emission characteristics of a substance. It has been applied to the quality assessment of crops and vegetables. We combined DL detection and chemometric methods to reveal the relationship between the internal changes and DL characteristics of RG with different steaming times. We also evaluated the functional properties of RG to compare the quality differences between samples. The results show decreasing DL decay curves and parameters (I0, T, Tau) with prolonged steaming. Chemometric and DL correlation analysis showed that there is a strong correlation between rare ginsenosides (Rg3, Rg5, Rk1) and DL parameters. Moreover, bioactivity test results showed that the three rare ginsenosides closely related to DL parameters may have more comprehensive immunomodulatory functions. Thus, DL effectively discriminates RG processed for different durations and helps characterizes potent rare ginsenosides. As a green, convenient, on-site detection technique, DL can provide robust support for RG quality control.