An integrated approach including "Content-Extractives-Activity" for comprehensive quality control of dietary supplement granules by portable near-infrared spectrometer coupled with the entropy weight method: Eucommia ulmoides granules as an example

Dietary supplements, with nutritional and health benefits, are widely used worldwide. Ensuring the quality of dietary supplements has become particularly important as demand increases. Current traditional methods of quality assessment tend to concentrate solely on the content of certain active ingredients; nevertheless, the bioactivity of a product, which serves as a more direct indicator of its quality, is frequently overlooked. Thus, a comprehensive "Content-Extractives-Activity" quality evaluation system was developed for dietary supplements using a portable near-infrared spectrometer combined with entropy weight method in this study. Taking Eucommia ulmoides granules as the object of study, near-infrared spectroscopy (NIRS) was used to predict the pinoresinol diglucoside content, ethanol-soluble extractives content, bioactivity indicators related to antioxidant damage such as cell viability value and intracellular malondialdehyde content, as well as comprehensive index. The best models all obtained satisfactory prediction results with correlation coefficient of prediction in the range of 0.89-0.97 and residual predictive deviation in the range of 1.81-4.19, which demonstrated the feasibility of the method for the rapid evaluation of the integrated quality of dietary supplements by NIRS.