Extraction,Purification And Stability Of Proanthocyanidins From Purple Cauliflower

Taking purple cauliflower as raw material,first,we determined the best extraction method was ultrasonic assisted cellulase extraction of Procyanidins from purple cauliflower with the extraction rate of proanthocyanidins as the standard of investigation.Then the extraction process is optimized by the Box-Behnken response surface design method,and the optimum extraction conditions are obtained.Next,through screening,AB-8 macroporous resin was used to purify,and the relative components of the extract were identified by high performance liquid.Finally,the stability of procyanidins was studied.The main conclusions were as follows:(1)We investigated the extraction rate of procyanidins by vanillin hydrochloric acid method under the same condition,with 15%acetic acid,15%hydrochloric acid,15%citric acid,60%ethanol,60%acetone,60%ethyl acetate,respectively the best effect,the extraction rate was0.43%,so the follow-up test selection of ethanol as extraction solvent.(2)The extraction rate of proanthocyanidins was taken as an investigation value.Single factor experiments were carried out on four factors including ultrasonic power,ultrasonic time,material to liquid ratio and ethanol concentration.The orthogonal test with four factors and three levels was designed to determine that the extraction rate of proanthocyanidins was 0.97%under the optimum extraction conditions.Microwave power,microwave time,material to liquid ratio and ethanol concentration were four factors for single factor experiment,and four factor and three level orthogonal experiments were designed.It was determined that the extraction rate of proanthocyanidins was 0.88%under microwave extraction.For the extraction of Proanthocyanidins from purple cauliflower,ultrasonic extraction has better effect than microwave extraction,so ultrasonic assisted cellulase extraction is applied.On the basis of single factor,the Box-Behnken of ultrasonic assisted cellulase extraction technology was optimized by response surface design method,the best conditions were as follows:2.1%of the amount of enzyme,enzymatic hydrolysis temperature 50,ultrasonic power 314.85W,enzymolysis time 40 min,ultrasonic time 27.38 min,the maximum extraction rate of Proanthocyanidins from purple broccoli.The maximum value is 1.50%.(3)Through consulting the data,the AB-8 macroporous adsorption resin was selected to purify the crude procyanidin,and the best adsorption flow rate was 1mL/min.The optimum desorption of ethanol was 70%.(4)The structure of proanthocyanidin extract from purple cauliflower was preliminarily identified by HPLC.Compared with proanthocyanidin standard,the results showed that the extract contained a small amount of impurities,but most of the extracts were procyanidins.(5)Study on the stability of purple cauliflower procyanidins showed that the procyanidins were sensitive to light conditions.The original anthocyanin was stable at pH 3.High temperature can reduce the stability of procyanidins.And the effect of metal ions on procyanidins in purple cauliflower was not significant,while the effect of K~+was significant.The stability of procyanidins was improved by adding a moderate amount of food additives,but the stability of procyanidins gradually decreased when the additive concentration was too high,the stability of proanthocyanidins decreased gradually,ascorbic acid,citric acid,sodium benzoate,adding amount of glucose was 0.4%,0.2%,0.2%,0.4%.