Peel and flesh antioxidant content and harvest quality characteristics of seven apple cultivars

The variation in the antioxidant content and the associations that may exist with harvest quality characteristics in peel and flesh tissue from seven apple cultivars were studied. Total antioxidant activity, total phenolic and ascorbic acid content, total soluble solids, total acidity and color parameters were measured in flesh and peel fruit tissues from the apple cultivars Fuji, Golden Delicious, Granny Smith, Jonagored, Mutsu, Starkrimson and Fyriki. In flesh tissue, Fyriki contained the highest antioxidant activity and total phenolic content (up to 82% and 67% more, respectively), while the lowest values were found in Fuji, Golden Delicious and Granny Smith. The ascorbic acid content was also greatest in the flesh tissue of Fyriki (up to 36% more). In peel tissue, the greatest antioxidant activity and total phenolic content were found in Starkrimson (up to 64% more) whereas the lowest values were found in Golden Delicious and Granny Smith. Apple peel contain from 1.5 to 9.2 times greater total antioxidant activity and from 1.2 to 3.3 times greater total phenolic content compared with flesh. Principal component analysis and correlation analysis showed that a more nutritious peel may be darker, redder and bluer, while a more nutritious flesh may have a lighter color and lower soluble solid content. It is concluded that Starkimson and the local cultivar Fyriki should be regarded as a valuable source of antioxidants, while fruit harvest quality characteristics may suggest for nutritional properties of apple.