Effects of chemical pre-treatment methods combined with electron beam irradiation on the quality of “Edor” longan

Using electron beam (EB) radiation as a quarantine treatment when exporting fresh fruit is a development trend in the world. In this study, the effect of EB irradiation treatment in the quarantine dose (400 to 1000 Gy) on the quality of export "Edor" longan was investigated. Investigation of chemical pre - treatments measure combined with EB irradiation to decrease pericarp browning of longan has also been carried out. “Edor” longan were treated by SO2 fumigation or dipping in 1,5 N HCl solution for 20 min after EB irradiation at low quarantine dose (400 Gy). Untreated and non-irradiated fruits were used as control. That all were then stored assumed commercial conditions (25-26°C). The results showed that the treated samples delayed a decrease in the total phenolic content and had lower pericarp browning than control. In addition, the treated samples were no significantly difference in terms of weight loss, TSS, total acid content, vitamin C, ... compared with the control. In particular, the treated samples had delayed the degree of damage level due to rotting when extending shelf life up to 22 days compared the control (12 days). Therefore, the method of combining SO2 fumigation treatment with EB irradiation (400 Gy) can be used for quarantine treatment of export "Edor" longan; and treatment with 1,5 N HCl solution can be considered to replace the traditional SO2 fumigation method.