Impact of ripening, harvest season, and the nature of solvents on antioxidant capacity, flavonoid, and p-synephrine concentrations in Citrus aurantium extracts from residue

Abstract

Sour orange (Citrus aurantium) is a rich source of flavonoids and alkaloids whose potential as nutraceutical ingredients and functional foods has been underutilized. Due to the above, for proper extraction of bioactive compounds from this citrus, the effects of some factors, such as harvest season, maturity, and solvent type used for extraction, remain to be established. Therefore, this study evaluates the effect of solvents nature (methanol, ethanol, or water), degrees of maturity (green, semi-mature, and mature), and harvest season of the year (winter, spring, summer, and autumn) of sour orange, on quantity and chemical nature of bioactive compounds extractions. Antioxidant capacity, total flavonoids content, and flavonoid/alkaloid contents were measured. The spring harvest´s semi-mature methanolic and aqueous green extracts showed the greatest antioxidant capacity and total flavonoid content (p < 0.005) The green methanolic extract from summer has fruits have the highest concentration of naringin (952±125 mg/g waste), neohesperidin (867±107 mg/g waste), and p-synephrine (554±72mg/g waste), p < 0.005. The differences between these extracts were because during the spring, stress due to climate changes generated the presence of flavonoids with higher antioxidant capacity. Our results allowed us to find the conditions that obtained the highest concentration of flavonoids and p-synephrine.

Keywords

• Sour orange
• Ripening
• Harvest season
• Antioxidant activity