Effect of Aloe vera gel on chilling injury, decay and nutritional quality of ‎pomegranate (Punica granatum L.) fruit‏ ‏during cold storage

Pomegranate (punica granatum L.) is one of the subtropical fruits and sensitive to chilling injury, so preservation of that in cold storage is associated with some limitations. In this study the impacts of Aloe vera gel (0, 40 and 80 %) on chilling injury, nutritional quality and decay of pomegranate fruit, during 90 days at 4 ºC and 85-90 % relative humidity were evaluated. Sampling to determination of intended criteria were done at 30, 60 and 90 days of cold storage. Results showed that Aloe vera gel decreased the chilling injury and decay incidence significantly and the lowest level of chilling injury (11.6 %) and decay incidence (18.66 %) were observed in fruits with 80% of Aloe vera gel treatment after 90 days of storage. Also this treatment controlled well the levels of malondialdehyde (as an indicator of membrane lipids peroxidation), electrolyte leakage, and weight loss. Furthermore, 80% of Aloe vera gel treatment enhanced the antioxidant capacity and the activity of superoxide dismutase, catalase and ascorbate peroxidase and preserved the ascorbic acid content at higher level. High levels of total phenols, flavonoids, and anthocyanins were observed in Aloe vera gel treated pomegranate fruits, as a result of a higher activity of phenylalanine ammonia-lyase and a low activity of polyphenol oxidase. In conclusion, applying of Aloe vera gel in 80 % concentration, as an natural cover, could increase cold stress tolerance and preserve nutritional values of pomegranate fruits during the storage period.