Polyphenol profiling of a red-fleshed apple cultivar and evaluation of the color extractability and stability in the juice.

Red-fleshed apples can be used for the production of innovative products such as rosé juices and ciders. Phenolic compounds including procyanidins (i.e., condensed tannins) and anthocyanins were quantified in the fruits and juices of a red-fleshed apple cultivar by chromatography coupled to UV-visible and mass spectrometry. Juice color was characterized by colorimetry. The influence of oxygen, pH, sulfites, ascorbic acid, and copper on the color stability of the juice was studied in an experimental design. Fruits were rich in polyphenols (0.5 g/100 g FW), with anthocyanins and procyanidins accounting for 9 and 73% of total polyphenols, respectively. Extractability of anthocyanins in the juice was 26%. Juice storage under air atmosphere at 35 °C resulted in significant browning with the anthocyanin level decreasing up to 86% after 14 days. In contrast, color was stable for storage under argon atmosphere. Sulfites, ascorbic acid, and copper have only a slightly influence on color stability in those conditions.