Abstract: Solvent-thermal method was applied for extracting naringin from shaddock peel of Enshi Gongshui (Citrus grandis Osbeck) using ethanol-water mixture as extraction solvent, and the naringin was determined by ultraviolet spectrophotometry. The recovery rate of naringin was from 96.51% to 101.9% with the relative standard deviation of less than 0.16%. The effects of extraction temperature, extraction time, ethanol concentration, shaddock peel powder size and filling factor on extraction rate of naringin were explored. The antioxidant activity and stability of naringin were investigated by flow-injection chemiluminescence and spectrophotometry. The results showed that the optimal process conditions were ethanol concentration of 70%, shaddock peel powder size of 120 mesh, filling factor of 80%, extraction temperature of 60 ℃ and extraction time of 3 h. The strong antioxidant activity and stability of naringin were simultaneously observed.

Key words: shaddock peel, naringin, solvent-thermal method, flow-injection chemiluminescence, antioxidant effect