Application of palladium-modified zeolite for prolonging post-harvest shelf life of banana.

BACKGROUND: The marketability of banana is limited by the rapid rate of ripening. However, the traditional post-harvest technologies may not be desirable. The aim of this study was to investigate the potential of a reusable material for the food preservation industry. RESULTS: The nanocomposite-based palladium (Pd)-modified zeolite (Pd/zeolite) was prepared by impregnating Pd into zeolite. Pd/zeolite had a Brunauer-Emmett-Teller dinitrogen specific surface area of 475 m2 g-1 with crystal structure similar to Y-zeolite. Transmission electron microscopy images showed the dispersion of Pd particles over the multi-pore zeolite support. Pd/zeolite uniquely acted as an adsorbent and a catalyst and was able to remove ethylene even after reaching breakthrough point. To prove Pd/zeolite is reusable, a 99 ± 0.8% ethylene removal efficiency still remained even after five consecutive cycles with repeated use of Pd/zeolite. The presence of Pd/zeolite significantly decreased the ethylene concentration during 18 days of storage at 20 ± 2 °C. CONCLUSIONS: Pd/zeolite could delay the ripening of banana and improve its firmness and the peel color significantly. Findings indicated that the as-prepared Pd/zeolite is an effective adsorbent/catalyst with high potential for practical application in ethylene removal, especially for the post-harvest period. © 2019 Society of Chemical Industry.

Quarantine Vapor Heat Treatment of Papaya Fruit for Bactrocera dorsalis and Bactrocera cucurbitae (Diptera: Tephritidae).

The presence of quarantine insect pests in fruit export can impede trade with other countries. Therefore, to reduce the risk of possible quarantine pests in exported fruit, postharvest disinfestation treatment is essential. This study investigated the effects of vapor heat treatment (VHT) on oriental fruit fly (Bactrocera dorsalis Hendel (Diptera: Tephritidae)) and melon fly (Bactrocera cucurbitae Coquillett (Diptera: Tephritidae)) which are major pests for papaya fruits. For inoculated papaya fruits weighing 550 ± 100 g, the optimal egg-inoculation density, rearing conditions, and heat tolerance for each developmental stages of both fruit flies were determined, and then analyzed to determine their survival, and assess papaya fruit quality after treatment. Result of VHT of each developmental stage indicated that the eggs of B. dorsalis were the most heat tolerant at 45.6°C. Efficacy test that determined the optimal mortality temperature was performed by subjecting 60 fruits infested with 4,500 eggs to fruit core temperatures of 44.2, 45.2, 46.2, and 47.2°C. It was found that when the papaya fruit core temperature increased at a heating rate of 0.0925°C/min from room temperature to 47.2°C in 3 h, fruit flies showed 100% mortality. Results of the confirmatory test using 300 papaya fruits also indicated 100% mortality at this temperature. Both fruit quality and injury test results demonstrated insignificant differences in color, appearance, soluble solids, or firmness of fruits before and after treatment. Thus, VHT effectively disinfested papaya fruits against both fruit fly species, thus making it a viable quarantine treatment for papaya fruits prior to their export.