Effects of Microporous Packaging Combined with Chitosan Coating on the Quality and Physiological Metabolism of Passion Fruit after Harvest

The postharvest quality of passion fruit deteriorates rapidly because of intense physiological metabolism and serious water loss. It is difficult to solve the problems of water loss and microbial growth of passion fruit during room temperature storage at the same time by use of a single chitosan coating or microporous packaging technology. Therefore, a dual modified atmosphere microenvironment based on microporous packaging (MP) and a chitosan coating (CH) was established, and its effects on the quality and physiological metabolism of passion fruit were evaluated. The results indicate that MP can effectively reduce water loss and that the CH inhibits microbial growth. Combined application (MP-CH) is found to significantly inhibit fruit weight loss, which shows a value of only 11.17% on Day 12, while the weight loss of the control is as high as 51.57%. The ascorbic acid and total phenol contents of passion fruit in MP-CH are 5.63 and 37.00 mg·100 g−1, respectively, on Day 12, which are markedly higher than those in the control. The activities of superoxide dismutase, peroxidase and catalase in MP-CH on Day 12 are 3.20, 2.22, and 1.52 times higher than those in the control, respectively, which effectively improve the antioxidant level and reduce the accumulation of malondialdehyde and hydrogen peroxide. Furthermore, MP-CH delays the degradation of protopectin, cellulose, and hemicellulose by inhibiting the activities of pectin methylesterase, polygalacturonase, cellulase, and β-glucosidase. Consequently, MP-CH is a promising method for extending the shelf life of passion fruit to 12 days at 25 °C by regulating water loss and physiological metabolism.