Influenza della temperatura di conservazione sulle proprietà funzionali del succo d’arancia pigmentata (Citrus sinensis, cv. Tarocco)

The antioxidants found in orange juice struggle against the cellular aging and some neurodegenerative diseases, allowing to classify the orange juice as a functional food for its ability to affect positively human physiological functions. This work is about blood orange juice extracted from “Tarocco” cultivar, stored at different temperatures. Analyses were performed on fresh and pasteurized juice, and on unprocessed and pasteurized orange juice after storage for 15 days at 6˚ C and -20˚C. pH, ˚Brix, total acidity, formol index, ascorbic acid, total anthocyanins, total flavonoids content and antioxidant capacity were determined. The thermal treatments of pasteurization, refrigeration and freezing, had different effects on several classes of compounds and chemical parameters. The combination of pasteurization and cooling determined an increase, mainly in acidity, in formol index and ˚Brix, whereas no evident changes were observed in fresh and frozen pasteurized juice. The heat treatment caused a general decrease in the anthocyanin and flavonoid content. Comparing the fresh juice with the cooled and frozen juice, the vitamin C content decreased in the pasteurized juice and in the pasteurized-refrigerated one, whereas it increased in the pasteurized-frozen juice. The pasteurized juice possessed a higher antioxidant activity than all other types of the studied juices.