Efficacy and mechanism of hot water treatment on relieving postharvest diseases of banana

The effects of hot water treatments(HWT) on the decay control, the defense enzymes and invitro Colletotrichum musae were investigated. Among the different temperatures(50℃, 52℃ and 55℃) used to treat bananas, 52℃ is the optimum temperature for disease control efficacy. The duration of HWT at 52℃, required for disease control, depended on whether the ripening treatment was imposed. Without ripening treatment, only 3 min was needed, but 5 min was needed for that with ripening treatment. Compared with the control, lower malondialdehyde(MDA) contents, and higher enzyme activities of peroxidase, chitinase and β-1,3-glucanase were detected in the peels of heated bananas. The inhibition effects of HWT at 52℃ on the spores of invitro Colletotrichum musae increased with time. Compared with the unheated control, 3-min HWT did not make significant difference, while 5-min and 10-min HWT significantly reduced the germination rate and pathogenicity. The results implied that the disease was reduced as the result of HWT which improved the activities of defense enzymes.