Research On Antioxidant Properties Of Polyphenols In Navel Orange Peel And Its Application

Navel orange is known as"the king of citrus", containing kinds of nutrients which is necessary for the body. Many wastes are left after fruit juice processing.There are a variety of active ingredients in wastes, including phenolic acids, flavonoids and other bioactive components,all of which have a good function in terms of anti-mutagenic, anti-tumor, anti-virus and so on, and a prevention in diseases which have serious harm to human health such as high blood pressure, heart disease and cancer. In this study, Navel orange peel is used as a research object, the extraction, antioxidation activities and the effects of polyphenol in navel orange peel on quality and storage of cantonese sausage were studied, and provided references for the utilization of navel orange peel.The optimum extraction conditions of pgenolics from navel orange peel were attained at a solid-to-liquid ratio(g/mL) of1:21by agitated maceration with50%ethanol at60℃in the dark for2h, and then extracted by diethyl ether-ethyl acetate(1/1,v/v)to obtained the aqueous phase and organic phase polyphenols.Both the DPPH radical scavenging(DPPH assay) and ferric reducing power(FRAP assay) were suitable to evaluate antioxidant activity of polyphenol in navel orange peel. The ability in removal of DPPH free radicals and ironion reduction of polyphenols in navel orange peel both present dual dependencies in dose and reaction time. Polyphenols in navel orange peel can inhibit the oxidation of oil, The citric acid and vitamin C exhibited synergistic effects to polyphenols in navel orange peel,and latter is stronger.Aqueous phase and organic phase polyphenols in navel orange peel are sensitive to temperature, pH, light. The content and antioxidant activities of aqueous phase and organic phase phenolics are tending to decline as the rising in temperature and light. Aqueous phase phenolics were not influenced in the pH3-5,and organic phase polyphenols are more stable in acidic, alkaline range. The content of polyphenols in navel orange peel display a substantial correlation with its antioxidant, and the antioxidant will change greatly when content change.The existent forms in navel orange peel of phenolics were free,esterified,and insoluble-bound phenolics, and the free form’s phenolics were the main existen form of phenolics in navel orange peel. Compared with standard antioxidants of BHT, phenolics in navel orange peel exhibited stronger antioxidant activity.And does effect between TPC and antioxidant activity of phenolic extracts were observed.Similarly, free, esterified, and insoluble-bound polyphenols in navel orange peel are sensitive to temperature, pH, light. The content and antioxidant activities of free, esterified, and insoluble-bound are tending to decline as the rising in temperature and light,and free,esterified,and insoluble-bound poly-phenols are more stable in pH3-5. The content of polyphenols in navel orange peel display a substantial correlation with its antioxidant, and the antioxidant will change greatly when content changed.The effect of polyphenol in navel orange peel on on cantonese sausage was researched. The results shows that the sensory quality and structure of cantonese sausage were affected by polyphenol in navel orange peel,and to a certain extent, the extracts can inhibit oxidation of cantonese sausages, extending its shelf life.