The quality of oysters is reflected by volatile organic components. To rapidly assess the freshness level of oysters and elucidate the changes in flavor substances during storage, the volatile compounds of oysters stored at 4, 12, 20, and 28 °C over varying durations were analyzed using GC-MS and an electronic nose. Data from both GC-MS and electronic nose analyses revealed that alcohols, acids, and aldehydes are the primary contributors to the rancidity of oysters. Notably, the relative and absolute contents of Cis-2-(2-Pentenyl) furan and other heterocyclic compounds exhibited an upward trend. This observation suggests the potential for developing a simpler test for oyster freshness based on these compounds. Linear Discriminant Analysis (LDA) demonstrated superior performance compared to Principal Component Analysis (PCA) in differentiating oyster samples at various storage times. At 4 °C, the classification accuracy of the optimal support vector machine (SVM) and random forest (RF) models exceeded 90%. At 12 °C, 20 °C, and 28 °C, the classification accuracy of the best SVM and RF models surpassed 95%. Pearson correlation analysis of the concentrations of various volatile compounds and characteristic markers with the sensor response values indicated that the selected sensors were more aligned with the volatiles emitted by oysters. Consequently, the volatile compounds in oysters during storage can be predicted based on the response information from the sensors in the detection system. This study also demonstrates that the detection system serves as a viable alternative to GC-MS for evaluating oysters of varying freshness grades.

The extraction process of crude polysaccharides from Agrocybe aegerita was optimized, and the antioxidant and anti-aging effects of the crude polysaccharides were evaluated. The optimal extraction parameters for the polysaccharide were identified using the response surface methodology. The DPPH, hydroxy radical, and superoxide anion radical scavenging capacities were evaluated to determine the antioxidant properties of the AAPs. The effects of the AAPs on the lifespan, head-swing frequency, swallowing frequency, body-bending frequency, and stress resistance of Caenorhabditis elegans were determined. The optimal extraction conditions included a solid-to-liquid ratio that resulted in an extraction solution concentration of 0.034 g/mL, an extraction temperature of 92.64 °C, and an extraction time of 2.82 h. Under these conditions, the yield of the AAPs was 11.325% ± 0.996%. The IC50 of the AAPs for superoxide anion radical scavenging was 4.693 mg/mL. The AAPs reached their maximum activity at concentrations of about 2 mg/mL for DPPH and 5 mg/mL for the hydroxyl radical. The AAPs could prolong the lifespan and improve locomotion and the stress resistance of C. elegans. Our findings illustrate the potential of AAPs as an anti-aging and antioxidant agent, highlighting the use of this natural compound in the fields of food and pharmacology.