Chemical Composition and Antioxidant Activity of Portuguese Diospyrus Kaki Fruit by Geographical Origins

Lately, several studies have demonstrated the health benefits associated with natural compounds consumption. Fruit phenolics, lycopene and ascorbic acid, have strong antioxidant, anti-inflammatory, antimugenic and anticarcinogenic activities. In the present study parameters related to fruit quality and climacteric conditions, such as color, moisture, pH, water activity, total phenolic compounds, ascorbic acid and lycopene content were analyzed. Diospyros kaki cv. chocolate fruits were extracted with different solvents, such as methanol, ethanol and water. Total polyphenolics of each extract determined by Folin-Ciocalteu method were found to be higher in methanolic extract (106.2 mg/100g sample) and lower in ethanol (21.9 mg/100g sample) considering Diospyros fruits with peel. The antioxidant activity (AA) was evaluated by an in vitro model system trough 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity (DPPH•) assay. Significant variations were found in the levels of these parameters according to different geographic regions. It was possible to describe correlations between the antioxidant compounds (polyphenolics, ascorbic acid and lycopene) and the antioxidant activity. Aqueous solvent was more effective on the extraction of antioxidant compounds from Portuguese Diospyros fruits with 52% radical scavenging activity. Results support the importance of Diospyros kaki cv. chocolate fruits, Portuguese cultivar, as a functional food with high antioxidant potential that may have beneficial effects against oxidative human damage.