Proteomic Investigation of Metabolic Changes of Passion Fruit Treated with Microporous Packaging Combined with Chitosan Coating During Storage

In our previous research, microporous packaging combined with chitosan active coating (MP-CH) treatment extended the shelf life of passion fruit at 25 °C to 12 days by regulating water loss and physiological metabolism. However, proteomic investigation and metabolic changes in passion fruit by MP-CH treatment are unclear. In this study, tandem mass tag (TMT) labeling combined with two-dimensional liquid chromatography tandem mass spectrometry (2D LC‒MS/MS) was used to monitor the metabolic changes in passion fruit treated with the MP-CH group and the control group. A total of 730 differentially expressed proteins (DEPs) were identified. Compared with the control group stored for 12 days, there were 359 DEPs in the MP-CH group, including 179 upregulated proteins and 180 downregulated proteins. The upregulated DEPs were mainly involved in the processes of L-ascorbic acid biosynthesis, anthocyanin-containing compound biosynthesis, aspartate family amino acid biosynthesis, and regulation of protein stability. The downregulated DEPs were mainly involved in oxaloacetate metabolism, carbohydrate metabolism, organic substance metabolism, cellular lipid metabolism, pectin catabolism, and galacturonan metabolism. Results showed that the expression of antioxidant enzymes in the MP-CH group was upregulated, which could enhance the antioxidant capacity and stress resistance of passion fruit. In addition, the expression of cell wall-degrading enzymes was downregulated, which could delay the degradation of cell wall components and maintain the relative stability of its cell wall structure, making for a further extended shelf life of passion fruit.