Abstract:
Abstract: The wax apple is one of the most popular fruits in Southeast Asia areas. However, the thin skin and fragile flesh are highly susceptible to mechanical damage during post harvesting, leading to the serious shelf quality of the fruits. This study aims to reduce the mechanical damage for better shelf quality of wax apples in the logistics and transport. The ISTA 6-AMAZON.COM-SIOC TYPE A (ISTA 6A) test standard was used to simulate the transportation of wax apples. Four types of common e-commerce packaging were set, P1: corrugated box + single-layer foam net, P2: corrugated box + double-layer foam net, P3: corrugated box + expanded polyethylene (EPE) liner, and P4: foam box + double-layer foam net. A systematic analysis was made to explore the quality change of wax apples during the shelf life (15 ℃, 8 d) after the test. The results showed that better shelf quality was achieved in the wax apples under the double-layer foam net (P2) group using the same outer packaging and the different cushioning type, compared with the single-layer foam net (P1) and EPE liner (P3). Specifically, the respiration intensity of wax apples was the most moderate, the value of skin brightness
L* was the lowest value at 32.86, the Browning Index (BI) of fruit flesh increased by 62.35%, and the rate of increase was the slowest. There were always low levels in the contents of malondialdehyde (MDA), peroxidase (POD) and polyphenol oxidase (PPO) activities. The behavior was attributed to the weak cushioning and protective performance of single-layer foam net. At the same time, the EPE liner hindered the heat loss and water diffusion of respiratory energy from the fruits. Using the same cushioning type and the different outer packaging, there was no significant difference in the impact of corrugated box (P2) and foam box (P4) groups on the related indexes of shelf quality, such as the respiratory intensity, BI value, and antioxidant-related enzyme activity of wax apples. Among them, better shelf quality was found in the double-layer foam net (P2) group, due to the less severe degree of mechanical damage and the slow browning of lotus fruit. The more compact arrangement between the fruits was obtained in the double-layer foam net, compared with the single-layer one. The smaller displacement during vibration effectively reduced the incidence and intensity of the mechanical damage. The shelf quality of the wax apple decreased in the EPE lining layer. The reason was that the porous structure of the foam net was conducive to the dissipation of heat and the diffusion of water, thus avoiding the formation of high temperature and high humidity in the packaging environment. As such, adequate support performance was obtained under the outer packaging. The double-layer foam net can be expected to serve as a cushioning packaging type. The vibration energy was distributed evenly in the whole fruit, leading to reduced mechanical damage. The wax apples dissipated their own respiratory heat, and then inhibited the antioxidant-related enzyme activity, finally maintaining the shelf quality of the fruits. In summary, the e-commerce outer packaging presented sufficient support performance in the wax apples as fresh agricultural products. The inner packaging required sufficient cushioning function. The excellent breathable and moisture permeable performance was achieved to protect the integrity of wax apple fruit in logistics and transport, thereby reducing mechanical damage to facilitate the diffusion of respiratory heat for better shelf quality. The finding can provide the theoretical background and technical reference for the further improvement of wax apples' e-commerce logistics preservation technology.