The effect of methyl jasmonate on internal browning incidence and postharvest quality of 'Huai-mun' pineapple fruit

The effect of methyl jasmonate (MeJA) on internal browning (IB) and postharvest quality of ‘Huai-mun’ pineapple fruit was investigated. Fruit were harvested at the green mature stage and dipped in MeJA at concentrations of 0 (control), 10^‑2, 10^‑3 and 10^‑4 M for 5 min prior to storage at 10°C for four weeks. Each week, fruit were randomly removed to room temperature for ripening prior to fruit quality determinations. A completely randomized experiment was conducted with four replications (1 fruit/replication). Data analysis was performed by using ANOVA and means were compared by using DMRT at 95% confidence level. MeJA did not reduce IB development in this study. The internal browning (IB) symptoms limited storage life to only 1.25 weeks after treatment with 10^‑2 M MeJA while it was 1.5 weeks in control fruit and in 10^‑3 M MeJA. A concentration of 10^‑4 M MeJA enabled fruit to be stored for 2.5 weeks. In addition, MeJA significantly (p<0.05) delayed fruit ripening as shown by only a small change in shell colour from green to yellow and delayed weight loss, especially at 10^‑4 M. Lightness (L*) value decreased during storage. Vitamin C concentration in the core and flesh decreased throughout storage. 10^‑4 M MeJA delayed electrolyte leakage during the first week of storage. Furthermore, MeJA slightly delayed changes in TA and SSC in extracted pineapple juice without any significant (p>0.05) difference. Therefore, the application of 10^‑4 M MeJA could maintain the quality of ‘Huai-mun’ pineapple fruit harvested at a mature green stage for up to 2.5 weeks at low temperature.