Influence of Variety on Total Polyphenols Content and Antioxidant Activity in Apple Fruits (Malus domestica Borkh.)

Abstract

Recently, an increasing interest in fruits and vegetable eating has been noticed in particular through epidemiological and biochemical studies pointing to their health benefits for human health. Specifically, apples (Malus domestica Borkh.) are one of the most frequently consumed fruits. Therefore, the current study aimed to compare the total polyphenols content (TPC) and antioxidant activity (AA) of apple fruits from different columnar apple trees growing in experimental conditions. For this purpose, fruits of 7 apple cultivars obtained from the Botanic Garden (Slovak University of Agriculture, Slovakia; vegetative season 2019/2020) were analysed. Among them, four green-yellow cultivars: Golden Delicious, Granny Smith, Goldcats, Rondo; one green cultivar with red spots: Kordona; one red cultivar: Redcats, and one pink cultivar: Pompink, were used. Method using the Folin-Ciocalteu reagent was applied to quantify TPC, and radical scavenging activity of the samples was measured with 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavengers. Total polyphenols content (mg GAE.g^-1 dry weight) ranged from 2.92 ±0.31 (cv. Pompink) to 9.02 ±0.32 (cv. Granny Smith), whereas statistically significant differences (p <0.05) were recorded between all analysed cultivars except for Rondo (5.07 ±0.44) and Kordona (4.18 ±0.35) cultivars as compared to Redcats (4.96 ±1.06) one. As with TPC, the lowest values for AA were observed in the Pompink cultivar (35.03 ±3.49 %) and, conversely, the highest ones in the cultivar Granny Smith (88.55 ±4.25 %). These results suggest that the values for TPC and AA in apple fruits are strongly influenced depending on the apple cultivars. From this aspect, upon achievement of this survey, and employing more samples, it will be possible to create a comprehensive overview of the antioxidant properties of apple fruits with the possibility of their application in the food industry to develop innovative products with added value.</p>