Changes in quality, endogenous enzyme activities, and their relationships during post-harvest storage of Phlebopus portentosus- an edible fungus

The postharvest quality of Phlebopus portentosus, a valuable edible fungus, is highly susceptible to spoilage due to endogenous enzymes during storage. This study investigated changes in firmness, weight loss, color, browning degree, malondialdehyde concentration, oxidation level, enzyme activities, and volatile compounds in P. portentosus during storage at 4 degrees C and 25 degrees C, alongside their interrelationships. Both storage conditions exhibited similar trends in quality deterioration, with slower changes at 4 degrees C and a critical turning point observed on the 4th day. The activities of polyphenol oxidase (PPO), peroxidase (POD), lipoxygenase (LOX), and phenylalanine ammonia-lyase (PAL) increased during storage, significantly impacting browning, oxidation, and volatile compounds, as confirmed by Pearson correlation analysis. These enzymes might be key factors affecting the postharvest quality of P. portentosus. This study would provide a theoretical basis for the development of postharvest preservation techniques for P. portentosus.