Researchs On Extraction And Purification Process Of Proanthocyanidins From Peanut Red Skin

Peanuts (Arachis hypogaea) is a kind of annual herb plant which belongs to Arachis L. and papilionaceae. Peanuts which have grown all over the country are one of main legume crops in our country. Peanut red skins which are reddish-brown pericarps around peanuts in the process of peanuts processing have not been effective and fully utilized. Peanut red skins are rich in bioactive constituents such as resveratrol and proanthocyanidins. Thereinto proanthocyanidins have the higher content than others. The study was to optimize the ultrasonic-assisted extraction and microwave assisted extraction of proanthocyanidins from peanut red skin. The results are as follows:(1)Spectral scan of procyanidins standard solution and extracting solution of proanthocyanidins from peanut red skin had been processing between400and600nm througth vanillin hydrochlo-ric acid method. The apices form and location were basically the same and maximum absorption peak was at500nm.(2)Through three kinds of solvents’ultrasonic-assisted extraction, the yield of proanthocyanidin from peanut red skin in descending order was:acetone> ethanol> methanol. Because of high yield of proanthocyanidins, acetone solution has been choosed to do the follow-on experiments. The single factors included acetone concentration, ultrasonic power, ratio of material to solvent, ultrasonic extraction time and ultrasonic extraction times. Results of single factor experiments are optimized by Plackett-burman experimantal design. It’s come to the conclusion that ultrasonic extraction time was20min and ultrasonic extraction times was2. Three factors: acetone concentration, ultrasonic power and ratio of material to solvent had been choosed to response surface design. The significant degree of the yield of proanthocy-anidins from peanut red skins was:ratio of material to solvent> acetone concentration> ultrasonic power. The optimum process conditions were as follows:Acetone solvent strength62%, ultrasonic frequency120W, ratio of material to solvent47mL/g. Under these conditions, the extraction rate was12.597mg/g.(3) According to the characteristics of microwave extraction apparatus, extraction solvent was identified as ethanol.The single factors included ethanol concentration, microwave power, ratio of material to solvent, extracting time and frequency. Extracting time and frequency were be determined by single factor tests and placket-burman experimantal design. They were20s and2times respectively. Three factors:ethanol concentration, microwave power and ratio of material to solvent had been choosed to response surface design. The significant degree of the yield of proanthocyanidins from peanut red skin was:ethanol concentration>microwave power>ratio of material to solvent. The optimum process conditions were as follows:microwave power528W, ethanol solvent strength55%, ratio of material to solvent22mL/g. Under these conditions, the extraction rate was11.32mg/g.(4)Compared with four kinds of macroporous resins by static adsorption and desorption test, HPD750which had the highest rates of adsorption and desorption had been choosed to purify proanthocyanidins crude products. The dynamic adsorption conditions were:pH of the solution4.0, sample solution concentration2mg/mL, flow velocity3mL/min. The dynamic desorption conditions:eluent was60%ethanol solution, elution speed was2mL/min, pH of the Eluent was7.0, dosage of eluent was75mL. Under these conditions, the adsorption and desorption rate were the highest.(5) According to the above conditions, after vacuum freeze drying purification degree of extraction from peatnut red skins were93.27%and92.46%.