Integration of chitosan coating and short-term hypobaric treatment extends postharvest life and upregulates defense-related enzymes in apple fruit

The limited postharvest life of fresh horticulture products can be ascribed to various factors among which diseases and disorders play an important role, leading to product and economic losses. Bull’s eye rot caused by Neofabraea perennans is one of the postharvest fungal diseases of apple fruits. We studied the efficacy of combined short-term hypobaric treatment and chitosan coating on fruit quality, disease incidence and consumer acceptability of apple fruits, after artificially inoculating the apples with N. perennans . Fruit were treated with hypobaric pressure (50 kPa for 4 h) and/or coated with 0.5%, 1%, and 2% chitosan, and a combination of both. All fruits were then stored for 120 days at 4 ± 1℃ and 85 ± 5% RH followed by sensory evaluation at simulated retail conditions for 15 d at 20 ± 3℃ and 65 ± 5% RH. Results showed that hypobaric treatment and chitosan coating, either alone or in combination, significantly affected enzyme activity, development of bull’s eye rot, physicochemical quality, and acceptability of apple fruit during storage. Among all the treatments, the best results were obtained by hypobaric treatment combined with 2% chitosan coating, which significantly maintained firmness (71.01 N), TSS (13.0 o brix), TA (0.34%), ethylene production rate (0.78 µmol kg −1 h −1 ), and respiration rate (0.40 mmol kg −1 h −1 ), increased the activity of Chitinase, Glucanase and Phenylalanine ammonia lyase (80, 133.67, and 156.7 U g −1 FW respectively), and prevented rot development (0%) until day 120. Moreover, the combined treatment had comparatively better overall acceptability (8.40) during its shelf life compared with control and individual treatments. However, further investigation is needed to evaluate the commercial feasibility of the study.