An environment-friendly strategy for direct characterization of polysaccharides in Auricularia auricula-judae by ATR-FTIR spectra and chemometrics.

The traditional polysaccharide component analysis often depends on utilization of chemical reagents, which pose potential threats to human health and environmental safety. The quantification analysis of Auricularia auricula-judae polysaccharides (AAPs) faces prominent challenges, e.g., operational complexity, high costs, and destructive samples, which make it difficult to meet the demands of high-throughput and green analysis. Up to now, there is unavailable of a green method for direct quantification of AAPs. Herein, this study firstly utilized Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectra integrated with chemometrics to simultaneously quantify O-acetyl, proteins, total polysaccharides, and uronic acids in AAPs. Specifically, these models were built using 84 samples and validated with 28 samples. The optimal preprocessing methods, i.e., SG9 + SD, SG11 + FD + SNV, SG9 + FD, and SG9 + FD + SNV, were applied to determine the four parameters via ATR-FTIR with partial least squares (PLS) regression models. The optimal models were confirmed to have strong predictive capabilities (R > 0.9000, RPD > 3) and without overfitting (RMSEP/RMSEC <3). Furthermore, the predicted and the actual values of four models exhibited high linear relationship in external validation (R > 0.9000, and RPD > 2.8). This study develops a non-destructive quantification strategy for AAPs, offering an environment-friendly analytical paradigm for polysaccharide research.