Alternation of flavonoid compounds in Valencia Orange fruit (Citrus sinensis) peel as a function of storage period and edible covers

Aim. The aim of this study was the investigation of the effect of clove oil and storage period on the amount of hesperidin and naringin component in orange peel (cv. Valencia). Methods. Four treatments including clove oil (1%), wax, mixture of wax-clove oil, control and storage period were applied. Treated fruits were stored at 7 degrees C and 85% relative humidity for 3 months and naringin, hesperidin, TSS, Vitamin C and antioxidant activity were measured every three weeks. The amount of hesperidin and naringin was determined using high performance liquid chromatography at the detection wavelength of 285 nm. Antioxidant activity was measured using the 1, 1-dipheny1-2-picrylhydrazyl-hydrate (DPPH) free radical scavenging assay. Results. Results showed that naringin and hesperidin were decreased during storage. Different treatment only had significant effect on the amount of hesperidin while storage period affected both of narigin and hesperidin. Results of correlation study, indicated strong relation between antioxidant activity and amount of naringin and hesperidin during storage time. However, at the end of storage period, the amount of hesperidin and naringin were diminished independent of different covers. Probably anaerobic condition caused such reduction. Conclusion. In conclusion, hesperidin and naringin of peels are suitable quality indexes indicating proper conditions for storage.