Postharvest irradiation as a quarantine treatment and its effects on the physicochemical and sensory qualities of Korean citrus fruits

Two Korean citrus fruits, Jinjihyang and Chunggyun, were exposed to gamma irradiation at 0, 0.4 and 1 kGy as an ionizing quarantine treatment and were then subjected to evaluations of physicochemical and sensory quality attributes during storage at 4 ± 1 °C for 0, 10 and 20 days. Upon irradiation at 1 kGy, the narinrutin content of Jinjihyang significantly decreased (109.64-94.80 mg/100 g), while hesperidin content remained stable. However, both flavonoids decreased significantly during storage in both fruit varieties. Vitamin C was stable after irradiation but a significant decrease (42.97-27.21 mg/100 mL) was observed in 1 kGy-irradiated sample at the 20th day of storage. Brix, organic acids, and sensory properties of both fruits were not affected by irradiation or storage. The 1 kGy-treated fruits showed the highest titratable acidity (%) but this was not reflected in the sensory scores, even though Jinjihyang was more susceptible to irradiation than Chunggyun. Overall, irradiation at less than 1 kGy shows a potential to be used as a postharvest quarantine treatment for Korean citrus fruits.