Studies On The Extraction Technique Of Polyphenol And Its Activity From Peanut Shell

Peanut shell as the waste of peanuts contains a lot of polyphenols. Plant polyphenols have many biological activities, such as anticancer, antibacterial, antioxidant, antiradiation, scavenging free radicals. In order to make full use of the peanut shell resource, in this paper, the extraction, purification of the peanut shell polyphenols and its antibacterial activity were studied, the results were as follows:The microwave-assisted extraction technology of peanut shell polyphenol was established in this paper. The ethanol concentration, liquid to material ratio, microwave time and extraction times were mainly considered to the extraction rate of peanut shell polyphenols. Box-Benhnken center combination method was applied to the response surface analysis, and a regression equation prediction model was established by SAS software for the analysis of response surface values, the optimal microwave assisted extraction conditions of peanut shell polyphenols obtained by the regression was as follows: 60% ethanol concentration, liquid/material ratio of 40:1, microwave time was 77 s for 1 time. The yield of peanut shell polyphenols was 15.69 mg/g under the optimum extraction condition.Based on static adsorption and desorption experiments, HPD-826 macroporous resin was selected as the best resin to purificate peanut shell polyphenol crude extract. Using single factor experiment,the effect of p H, concentration of peanut shell polyphenol, rate of sample loading on HPD-826 macroporous resin adsorption, and ethanol concentration and elution speed on desorption were studied. The results showed that the optimal conditions for adsorption were: p H 5.0, loading sample concentration was 3.0mg/m L, loading rate was 1.5m L/min, the optimal conditions for desorption were : 70% ethanol, elution speed was 1.5m L/min. After purification process, the purity of peanut shell polyphenol could reach 58.96% in the sample.Using the filter method, the inhibitory zone diameter was used as evaluation the antibacterial activity of peanut shell polyphenol, its antimicrobial stability was studied. The results showed that: peanut shell polyphenols had a good inhibitory effect on Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and displayed the strongest inhibitory activities on Escherichia coli, The MIC for Escherichia coli is 0.2 mg/m L, and for the other two bacteria was 0.3 mg/m L. When p H was at 5~7, the peanut shell polyphenol displayed the strongest antibacterial activity.