Evaluation of Color, Phytochemical Compounds and Antioxidant Activities of Mulberry Fruit (Morus alba L.) during Ripening

Abstract

Mulberry fruits are used for food, cosmetics and medicine. Several phytochemical and bioactive compounds in mulberry fruits are widely used for health benefits. During the ripening stage of mulberry fruits, different phytochemicals are present. This study investigates color, phytochemical compounds and antioxidant activity in mulberry fruit during seven ripening stages. The results indicate that the color changes from green to purple. The green stage contains high levels of vitamin c (12 mg/gDW), while the purple stage has the highest sugar levels, particularly fructose (241 mg/gDW) and glucose (171 mg/gDW). Trends of amino acids, anthocyanin and vitamin C increased initially, peaking in M6 and then declined in the final ripening stage (M7). Phenolic acid, flavonoids and γ-aminobutyric increased when the ripening level increased. The antioxidants activity was analyzed by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical and ferric reducing antioxidant power (FRAP) assays. It was found to have the highest contents in M7 at 19 mgTE/gDW (DPPH) and 22 mg FeSO4/gDW (FRAP), which were positively correlated with the total phenolic and total flavonoid contents. This study provides information on mulberry fruit during ripening that should be helpful in designing products while maintaining its high antioxidant content, excellent bioactivity and quality for use in food, cosmetics and medicine.