Antioxidant capacities and carotenoids evaluation of fresh and refrigerated peach and nectarine cultivars from Italy

Chemical-physical properties, colour parame ters, antioxidant activities (AA), carotenoid and polyphenol levels (CL) in seven cultivars of yellow flesh peaches , five cultivars of yellow flesh nectarines and one cultivar of white flesh nectarines at harvest time and after 7 days of cold storage were evaluated. Peaches had major variability in flesh firmness (FF) and titratable acidity (TA) and lower soluble solid concentration (SSC) than nectarines . Evaluation of ground colour parameters, a*, b* and L*, showed that nectarines had a yellow-orange hue with high lightness, while peaches were darker, tending to red-green . Hydrophilic, lipophilic antioxidant activities of extracts (W-AA and L-AA), carotenoids and polyphenols levels (CL and PL) were evaluated and their relation with commercial maturation. The average of W-AA at harvest time was 11.0 TEAC, while the L-AA values at harvest time was on average higher in peaches (2.0 TEAC) than in nectarines (1.3 TEAC). 'The yellow flesh had higher amounts of total carotenoids (182.45 ug/l00 g fw for peaches and 117.37 ug/100 g fw for yellow flesh nectarines). During cold storage, W-AA increased for nectarines (+22.9% in yellow flesh and +19.2% in white flesh) and peaches as well as polyphenolic compounds (+13.37%) while, contents of carotenoids decreased (-8.7%).