Changes of Flavor and Quality of Pleurotus eryngii Packed with Nano Film in Vacuum during Storage

In order to extend the shelf life of Pleurotus eryngii in nanofilm vacuum packaging, the fresh postharvest Pleurotus eryngii was placed in TiO₂ and SiO₂ composite nanofilm fresh-keeping bags, the sample was precooled to below 4 ℃ under 0.07 MPa and then stored at 2 ℃. In order to evaluate the dynamic changes of flavor qualities during storage, the free amino acids and the volatile flavor compounds were analyzed at 0, 20, and 40 days. The results showed that 17 free amino acids were detected, including 7 essential amino acids. The total amount of amino acids was 1196.15 mg/100 g, 1425.26 and 1629.77 mg/100 g on day 0, 20 and 40, and the content of delicious amino acids increased with storage time. A total of 36 volatile compounds were detected. The alcohols and esters were the two main components, which accounting for about 90% of the total volatile compounds content. The Venn diagram of volatile compounds, the heat diagram of relative content, and the PCA load diagram of key volatile substances revealed that the types and contents of volatile flavor compounds of Pleurotus eryngii changed significantly (P<0.05) during storage. On 0, 20 and 40 days, the content of alcohols accounting for 33.49%, 72.14% and 77.25% of the total volatile flavor compounds, while the values of esters were 56.56%, 22.23% and 9.76%. According to the QDA analysis of aroma characteristics, the aroma characteristics of the three storage periods were mushroom flavor, flower and fruit flavor, and pungent fat flavor, respectively. Ethanol and 1-pentanol could be used as markers to characterize the degree of Pleurotus eryngii corruption. Fresh Pleurotus eryngii vacuum-packed in nanofilm could better maintain their flavor qualities and prolong their storage period.