Peach polyphenol and carotenoid content as affected by frozen storage and pasteurization

The profile of polyphenol and carotenoid of peach were analysed on fresh fruits, immediately after freezing or after pasteurization, and during frozen storage at -20 °C for 360 days. Freezing did not affect the concentration of polyphenols or carotenoids. Pasteurization of fresh and frozen samples induced an increase in the extractability of chlorogenic acid (38% and 24%) and of zeaxanthin (336% and 127%) and a decrease of lutein (22% and 56%) and β-cryptoxanthin (32 and 51%).Total antioxidant capacity and total phenolic content changed by less than 20% after frozen storage for 360 d. However, total carotenoid content decreased 41% and 48% in unpasteurized and pasteurized samples, after the same storage period. Long term storage induced an increase in the extractability of (+)-catechin (47%) and zeaxanthin (90%) and a decrease in neochlorogenic acid (59%), chlorogenic acid (39%), quercetin-3-glucoside (21%), lutein (24%) and β-cryptoxanthin (40%). Pasteurization of frozen samples promoted a decrease in the concentration of neochlorogenic acid (91%), chlorogenic acid (87%) and quercetin-3-rutinoside (71%) and increase in lutein (16%), β-cryptoxanthin (42%) and β-carotene (31%).Peach should be stored for periods no longer than 230 d, since pasteurization after that, induced a higher decrease in neochlorogenic, chlorogenic acids and quercetin-3-rutinoside content.