Functional properties of newly-bred ‘summer king’ apples

In this study, we investigated the various physiological properties of ‘Summer King’ apples (Malus domestica Borkh) to highlight this fruit as a high value functional food source. The peels of newly-bred ‘Summer King’ apple were extracted using water and ethanol, and each extract demonstrated relatively high levels of phenolic compounds at 4.41 mg·g^-1 and 7.39 mg·g^-1, respectively. The water and ethanol extracts also showed antioxidant protection factor (PF) levels of 3.37 PF and 2.65 PF, respectively, and the antioxidation effects towards thiobarbituric acid reactive substances were 38% and 30% at 100 µg·mL^-1 phenolic concentrations. Therefore, extracts of ‘Summer King’ apple possess substantial properties for anti-aging. The anti-inflammatory effect (hyaluronidase inhibition) of the extracts were 4.97% for the water extract and 20.40% for the ethanol extract, both at a 200 µg·mL^-1 phenolic concentration. Both the water and ethanol extracts showed low α-amylase inhibition effects, but each demonstrated 93.59% and 98.80% α-glucosidase inhibition at a 200 µg·mL^-1 phenolic concentration, respectively. In an anti-wrinkle assay, the water extract showed 14.55% and 67.73% inhibition of elastase and collagenase, respectively, and the ethanol extract had 56.50% and 77.81% inhibition, respectively. These results support the high potential for the use of these extracts in functional food and cosmetics, and the ‘Summer King’ apple peel was determined to have various functions including anti-oxidation, anti-inflammation, anti-wrinkle, and anti-diabetic effects.