Production of a Safe and Efficient Antioxidant-Rich Extract from Sweet Orange (Citrus sinensiscv Shahsavari) Peel

The aim of this study is to develop an extraction method for the producing of a safe and efficient source of antioxidant compounds from fresh and pre-treated sweet orange (Citrus sinensis cv shahsavari) peel. Three types of solvents (100% ethanol, 100% water and ethanol-water mixtures at the ratios of 35:65 and 65:35, v/v), three duration times (60, 120 and 240 min) were chosen as the parameters affecting the phenolic compounds and flavonoid contents, extraction yield and antioxidant activities. These properties were evaluated by using the Folin-Ciocalteu method, DPPH radical scavenging activity assay and the aluminum chloride colorimetric method, respectively. The results showed that the extraction times within the current range of 60-240 min have no significant effect on the investigated properties. The binary water-ethanol mixture at the ratio of 65:35 showed the best extraction yield for total phenolic compounds of fresh orange peel. The lowest IC50 and the highest antioxidant activity observed in this extract sample indicated a possible synergistic effect among the phenolic compounds with different polarities. Pretreatment of the orange peel by liquid nitrogen resulted in maximum antioxidant activity that may be related to the releasing the bounded phenolic compounds.