Effect of frozen storage on the anthocyanins and phenolic components of pomegranate juice

Pomegranate juice's valuable nutritional components may be reduced during its processing or storage. This work examined the effect of frozen storage at -25 °C on some chemical characteristics of pomegranate juice. Total anthocyanin content of pomegranate juice, which was measured using the pH differential method, decreased by 11% after 20 days of frozen storage. Phenolic components, measured using a Folin and Ciocalteu assay by means of a UV-vis spectrophotometer, decreased by 29% after 20 days of frozen storage. Antioxidant activity, measured based on the radical scavenging properties of the juice using the 2,2-diphenyl-1-picrylhydrazyl method, decreased by 50% after 20 days of frozen storage. Pomegranate juice has 5 major anthocyanins, including Cyanidin 3-glucoside, Cyanidin 3,5-diglucoside, Delphinidin 3-glucoside, Pelargonidin 3-glucoside and Pelargonidin 3,5-diglucoside are 5 major anthocyanins of pomegranate juice. They were measured using the LC-MS method and results showed that Pelargonidin 3,5- diglucoside had the greatest decrease. Also, the LC-MS method showed that ellagic acid decreased by 15%.