Calcium ascorbate treatments to control the fresh-cut apple quality reduction when stored at high temperature

Previous studies have demonstrated that apple slices dipped in 20% calcium ascorbate (CaAsc) reduced the browning, allowing a shelf life of 28 d when stored at 4°C, and storage at 0°C is best practice. However, the use of low storage temperatures for fresh-cut fruit could be difficult to implement in some countries, markets or in the home refrigerator. For that reason, the effect of storage temperature (0, 4 and 8°C) in 'Braeburn' apple slices dipped in CaAsc (0 and 20% w/w), stored in air for up to 28 d was studied. Changes in antioxidant levels were measured using reducing activity (FRAP) and ascorbic acid content (AA). Changes in browning and sensorial quality were measured to indicate eating quality. CaAsc dips increased the initial levels of AA from 0.19 g kg^‑1 in the untreated slices to 3.94 g kg^‑1 for the 20% CaAsc treatment. After 28 d of storage, the AA reduction in treated slices was 33% when stored at 0 and 4°C and 74% at 8°C. For FRAP, the antioxidant activity decrease was 42, 65 and 69% for slices stored at 0, 4 and 8°C, respectively. In terms of overall quality, untreated slices did not achieve acceptable quality at a shelf life of even 7 d for any temperature studied. However, treated apples extended the shelf life to less than 21 d when stored at 8°C, and 28 d when temperature of 0 or 4°C was used. Thus, the use of CaAsc dips in apple slices can moderate the overall quality reduction when high storage temperatures are used, but a temperature of 0 to 4°C is the optimum storage temperature.