Metabolomics-based analysis of the effects of different storage temperatures on the post-harvest quality of truffles

To investigate the effects and mechanisms of different low-temperature storage conditions on the postharvest quality of truffles. This study used truffles from Huidong County, Sichuan Province as the research subject, setting four storage temperatures: -4 °C, 0 °C, 4 °C, and 20 °C. Physiological indicators such as postharvest decay rate, relative electrical conductivity, and respiration rate were measured. These were combined with metabolomic analysis to screen for differential metabolites and metabolic pathways. The results showed that truffles stored at -4 °C have a relatively low rot rate and are better suited for storage(P < 0.05). However, the relative electrical conductivity and MDA content of truffles stored at -4 °C were significantly higher than those in the 0 °C and 4 °C treatment groups (P < 0.05). The SDH activity of truffles stored at 0 °C and 4 °C was significantly higher than that of the -4 °C group in the later stages (P < 0.05). CAT activity was significantly higher in the -4 °C group than in the other groups during the first 21 days of storage(P < 0.05). Metabolomic analysis revealed that the -4 °C vs 4 °C group had the most differential metabolites in the positive ion mode, with pathways such as branched-chain amino acid metabolism, glutathione metabolism, and steroid biosynthesis being significantly enriched (P < 0.05). This study systematically reveals the effects of storage temperature on truffle preservation and its mechanisms, providing a theoretical basis for postharvest preservation of truffles.