2026 Volume 95 Issue 3 Pages 364-377
Gamma irradiation is widely used for the disinfestation of insect pests in fruits under plant quarantine. However, its application can negatively impact on fruit quality. In pineapple, irradiation has been reported to accelerate internal browning (IB) and increase susceptibility to rot disease during storage. This study investigated the effects of pre-treatment with ethanolic shellac-modified coconut oil (ES-MCO) coating and hot water dip (HWD) on reducing IB and fruit rot disease in gamma-irradiated pineapple cv. Pattavia. Pineapples were subjected to the following pre-treatments: (1) ES-MCO coating solution (8% shellac + 2% modified coconut oil), (2) HWD at 46.5°C for 30 min, (3) HWD followed by ES-MCO coating, and (4) 500 ppm fungicidal prochloraz. After pre-treatment, fruits were irradiated with gamma rays at a dose of 400 ± 10 Gy. Additionally, (5) gamma-irradiated (GI) and (6) non-irradiated pineapples without pre-treatment served as controls. All fruit samples were stored at 13°C for 21 days and then transferred to 25°C for 2 days to stimulate shelf-life conditions. The results showed that GI induced IB, and pre-treatment with HWD accelerated IB in GI-treated fruit. Pre-treatments with ES-MCO alone and HWD + ES-MCO effectively alleviated IB symptoms, suppressed polyphenol oxidase (PPO) activity, total phenolic content accumulation, and quinone formation in GI-treated fruit. Quality analysis revealed that HWD + ES-MCO pre-treatments delayed peel and pulp color changes, reduced the respiration rate and ethylene production, maintained total soluble solids and ascorbic acid content, and slowed the increase in titratable acidity in GI-treated fruit. Moreover, HWD + ES-MCO pre-treatments significantly reduced fruit rot severity, with efficacy comparable to prochloraz. Overall, the findings suggest that HWD + ES-MCO is a promising pre-treatment for alleviating IB severity, preserving fruit quality, and reducing rot disease in gamma-irradiated pineapples.
