Ultrasonic-assisted Extraction And Antioxidant Activity Of The Polyphenol From Banana Peel

With the development and advancement of science and technology，the study ofnatural products is getting hotter and hotter．Plant polyphenols is a natural active substancewhich has been proven to posses various activities such as the antioxidant，anti-pathogenicbacteria．At present，plant polyphenol has applied in the field of Cosmetics，Food，Agriculture and Polymermaterials．In this paper，ultrasonic extraction methods was the way to extract polyphenols onfresh banana peels，identifing the main factors affecting the extraction rate which were theratio of solid to liquid，ethanol concentration，ultrasonic time and ultrasonic power．Andthe solid-liquid had more impact than the effect of ethanol concentration on，followed byultrasonic time．Ultrasonic power was the minimal impact．Under extracted twice，theconditions of optimum extraction was identified as the follow：solid-liquid ratio of1：4（g：mL)，the ultrasonic power was500W. The ultrasonic time was40minutes，and theethanol volume fraction was65%．In this paper，the purification steps used the method of DM-301macroporousresin．The concentration of the sample controled in3.0mg/mL，and the flow rate was of1.0mL/min．The effluent was detected every20minutes．With the change of the totalconcentration over time，we can draw the curve of the dynamic adsorption．In the elution，the selected concentration is60%ethanol solution，and the flow rate is0.5mL／min．Thenwe drawed the dynamic desorption curve of the total polyphenol concentration changedover time．The result of the polyphenols content is83.90%in calculation．By the methodsof color reactions and UV scanning analysis used to the sample of crude extract andpurified which was initially determined contained the structure of flavonoids andpolyphenol．In this thesis，using the method of GB detect the effect of the banana peel polyphenolson the peroxide value of soybean oil．And banana peel polyphenol crude extraction andpurified extracts affected the antioxidant capacity of soybean oil．Compared with the blankgroup，we found that banana peel polyphenol crude extracts and purified extracts hadantioxidant effect on soybean oil．But compared with the control group，we could seethat the antioxidant activity of purified was less than the concentration of crude extractsin the same time time and the antioxidant activity of crude extracts was less than Vc．...