The effect of maturity, sunburn and the application of sunscreens on the internal and external qualities of pomegranate fruit grown in Australia

Consumer interest in pomegranate fruit (Punica granatum L.) is increasing in Australia as a result of its unique external and internal qualities. This work looked at the effect of applying sunscreen treatments to pomegranate fruit on the degree of sunburn damage and the effect of maturity and sunburn on the internal antioxidant concentration of the juice. The pomegranates, cultivar ‘Wonderful’ were grown in Condobolin, New South Wales, Australia.The Kaolin based sunscreens Surround® and Parasol® significantly reduced the severity of sunburn damage but treatment with Anti-stress-500® did not. There was no significant affect of the sunscreen treatments on the total phenolic content or total antioxidant activity of the juice. However sunburn damage did significantly reduce both bioactive parameters in the juice. The results indicate that the sunburnt pomegranate fruit did not have the capacity to prevent oxidative stress as indicated by the visual damage and the reduced pool of soluble antioxidants in the juice. Total phenol content and the total antioxidant activity of the juice also decreased significantly during fruit growth and maturity.More work is needed to determine the affect of sunscreen treatments on the internal quality of pomegranate juice grown under milder conditions. This work highlights how the physiological response of fruit to the environment impacts fruit quality both externally and internally.