Effects of low-density polyethylene inner liner on keeping the postharvest quality in 'Fuji' apple during storage

Apples are prone to superficial scald after long-term cold storage. We studied the effects of low-density polyethylene (LDPE) inner liners with 10, 20, 30, and 40 perforations of 150 μm on the quality and superficial scald of the 'Fuji' apple. The LDPE liner with 10 perforations (LDPE-10) formed microenvironments with lower concentrations of O₂ (15.96 %-17.9 %) and higher concentrations of CO₂ (0.59 %-1.19 %). Compared with the control (CK), the ethylene release rate of apples packed in LDPE-10 was reduced by more than 31.47 %, and the weight loss of the fruits in LDPE-10 was significantly reduced by 41.41 %. Notably, the LDPE-10 reduced the incidence of superficial scald and internal flesh browning by 16.45 % and 1.68 %, respectively. Lower contents of O₂ ^- reflected a better antioxidant capacity of fruit treated by LDPE-10 and MDA which resulted from more antioxidant secondary metabolites, including phenols, GABA, GSH and ASA, plus with higher activities of anti-oxidases, including POD and CAT, and together with lower PPO activity. This work provides an effective way and a theoretical foundation for improving the traditional mechanical refrigeration of apple fruits.