Free Radical Scavengering and Phenolic Compounds of Peel and Pulp of Quince

Abstract

This study aimed to determine the amount of flavonoids, anthocyanins, total phenolic compounds, ascorbic acid and antioxidant activity of the peel and pulp of the quince (Cydonia oblonga Mill.) in the polar and nonpolar sub-fractions of methanol extracts with two extraction methods, Soxhlet and microwave. The antioxidant properties were assessed by the ability to quench the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and β-carotene bleaching assays. The results showed that the Soxhlet method extracted higher amount of the phytochemicals. In the DPPH system, the highest radical scavenging activity was seen by the polar sub-fraction of the methanol extract in the peel of quince fruit (IC50=52±7.3 μg/mL). Among all the extracts analyzed, the polar sub-fraction of the peel extract exhibited a significantly higher total flavonoid (62.33±3.1 mg CTE/100 g), anthocyanin (1.54±0.24 μg C-3-GE/100 mg fresh weight), phenolic content (108.14 μg GAE/mg) and antioxidant activity than other samples with Soxhlet extraction method. Fruit has a number of bioactive ingredients and many of them were concentrated in the peel of the fruit rather than the flesh. Therefore, enjoy the benefits that unpeeled fruit offers! The present study revealed that the peel of quince fruit has higher phytochemicals and antioxidant properties when compared to the pulp.