Ultrasonic extraction and antioxidant activities of apple polyphenols

Apple is rich in many bioactive substances, such as vitamins, minerals, flavonoids, phenols etc., and it can prevent many kinds of diseases.Proanthocyanidin and chlorogenic acid are main phenol materials in apple.Taking the Rolls apple as research material, this research established the optimum technological parameters of supersonic extracting conditions of apple polyphenol (AP), then made a study on their vitro anti-oxidation character, and further proved the DPPH (1, 1-Diphenyl-2-picrylhydrazyl) radical and ·OH radical-inhibition effects by means of DPPH and 2oxidize-D-ribose method.The results showed that ethanol could act as the favorable extracting solvent for AP;the optimum ultrasonic extraction technological conditions were 20 minutes of time length, 60℃ of temperature, 60% of the ethanol and 6 to 1 of the solvent-dissolved matter ratio.Meanwhile, the scavenging action of DPPH radicals in AP was better than that of tea polyphenol and BHT, and it had the same antioxidant activities with BHT.Apple extracts had powerful antioxidant activities within certain concentration of 8-10 mg/mL.In addition, apple extracts and grape seed extracts with proanthocyanidins and chlorogenic acid as main component showed much better antioxidant activities than tea polyphenol.