Physical and Nutritional Quality Changes of Pomegranate As Affected by Different Storage Conditions

With global demand for pomegranate (Punica granatum L.) on the rise, there is an interest by growers in the SE US in the fruit as a new commercially viable option. The interest is primarily related to the high phytonutrient content of the fruit.  However, little is known of the postharvest quality and storage potential of the locally grown cultivars.  For this study, 13 cultivars were harvested at two maturities (early and late) and each stored at 2 different conditions: regular air storage (RA; 5 °C, 90 to 95% R.H.) or controlled atmosphere storage (CA; 3% O₂,  5% CO₂, 5 °C, 90 to 95% R.H.) for 3 months. After harvest and removal from storage, fruit were evaluated for numerous physical quality parameters, such as weight, colour, skin smoothness, and disease, as well as physiochemical parameters, such as total soluble sugars (TSS), titratable acids (TA), and phytonutrient content, after 1 and 7 days at room temperature (21°C).  It was found that the TSS content of stored fruits was affected by the maturity at harvest. The late harvested fruits had significantly higher TSS than early harvested fruits. TSS was also affected by the interaction between storage condition and day. The fruits stored in CA had significantly lower shriveling and smoother rind than fruit stored under RA conditions.  Although TSS was approximately equal in the majority of the cultivars, the sugar to acids ratio varied considerably, ranging from 5 to 30.  There were also significant differences between weight and juice content of the arils, which is an important consideration for the fruit destined for juice production.  Two disease causing organisms recently identified on Georgia pomegranate fruit are Cercospora and Botryosphaeria, with relatively frequent incidences of the former with a possible natural resistance of some cultivars apparent.  Total phenolic content and DPPH radical scavenging tended to decrease with harvest maturity, while total oxyradical scavenging capacity tended to increase.  Significant differences in anthocyanin content were found, both among cultivars and in response to storage and shelf effects.  Results suggest that numerous cultivars are of sufficient quality to be considered for commercial production in Georgia.