Effect of Vacuum Precooling on the Lignification and Related Enzyme Activities of Tricholoma matsutake

In order to investigate the effect of vacuum precooling treatment on the lignification of Tricholoma matsutake during storage, the changes in the hardness of cap and stalk, pulp firmness, lignin, chitin and cellulose contents, and the activities of cellulase (CX), phenylalanine ammonia-lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO) were studied during storage. The results showed that compared with the control group, vacuum precooling treatment could significantly inhibit the decline in the hardness of cap and stalk and pulp firmness, effectively inhibit the degradation of chitin and the increase of CX activity in the cell wall, maintain a higher cellulose content, and delay the accumulation of lignin. In addition, it could decrease the peak PAL activity of cap and stalk by 8.2% and 2.9%, the peak POD activity by 10% and 3.7%, and the peak PPO activity by 23.1% and 5.2%, respectively. In addition, compared with the cap, the peak time of lignification in the stalk was earlier, and lignification phenomenon was more likely to occur in the stalk. Therefore, vacuum precooling treatment can delay the lignification process and maintain the quality of T. matsutake.