The Effect of UV Irradiation and Packaging Type on Anthocyanin Content, Antioxidant Activity and Microbial Population in Pomegranate Fruit (cv. Malas Saveh) During Cold Storage

Anthocyanin content, antioxidant activity and the bacterial and fungal colonies in pomegranate fruit juice as well as visual quality of the fruits (cv. Malas Saveh) were evaluated through 120 days of cold storage (5±1°C). Four packaging styles including gapped and closed wooden boxes with and without polyethylene fruit coverage, and three irradiation treatments comprising 0.0 (control), 5.0 and 15 minutes UV (1.435W.m-2 intensity) exposure time were applied. Packaging and UV irradiation treatments had no significant effects on anthocyanin content, but the interaction between these two factors was significant in this respect. Fruits with polyethylene coverage had the higher antioxidant activity compared to the non-covered samples. In addition, the greatest antioxidant capacity was obtained from the 5 minutes UV exposure time. Between the irradiation levels, the numbers of bacterial and fungal colonies were higher in the control fruits than the two other treatments. Using polyethylene coverage considerably reduced the bacterial contamination, while this increased the fungal infection, but irradiation of fruits greatly decreased the negative effect of polyethylene coverage on fungal infection. Overall, UV irradiation significantly controlled fungal infection without putting the negative effects on anthocyanin content, antioxidant activity as well as pomegranate fruit taste and flavor. In addition, utilization of polyethylene coverage could keep the visual quality of pomegranate (cv. Malas Saveh) fruit in cold storage.