Chemical composition and deterioration mechanism of Pleurotus tuoliensis during postharvest storage

Pleurotus tuoliensis is a popular edible and medical mushroom, but it is highly perishable during postharvest storage. The quality parameters, chemical composition, malondialdehyde (MDA) concentration, and activity of metabolic enzymes were studied during 12 days of storage at 4 degrees C and 6 days of storage at 25 degrees C. Degradation was well described by changes in quality parameters, losses in nutritional value, increased metabolic enzyme activity, the accumulation of MDA concentrations, and the increase of total phenolic (TP) content. The phenylalanine ammonia lyase (PAL) significantly positively correlated with TP, which suggested an underlying mechanism of browning that the increased PAL activity stimulates the biosynthesis of phenols through the phenylalanine pathway. These results suggest that increased activity of laccase, lipoxygenase, PAL, TP and MDA accumulation, together with polysaccharide degradation, are the main factors involved in the deterioration of P. tuoliensis during storage.