Study On Extraction And Antioxidant Activity Of Wine Grape Seed Procyanidins

Proanthocyanidins are the main active substances of grape seed polyphenols. Modern research shows that, as antioxidants, proanthocyanidins do not only have high activity, But also protect cardiovascular, anti-cancer, anti-radiation, care and white skin. In this experment, extraction technics, purification and antioxidant activity of this substances were studied as follow:Proanthocyanidins content was determined colorimetrically by the vanillin-H2SO4assay using the catechin as the standard. With the content as index, the optimal extraction conditions were determined by the single factor and orthogonal experiment. In the ultrasonic extraction experiments, the results showed that the reaction conditions were ultrasonic power80W, solid-liquid ratio1:35, ultrasonic time30min, concentration of alcohol50%, and the extration of procyanidins content was55.728mg/g. In the microwave extraction experiments, the results showed that the reaction conditions were solid-liquid ratio1:25, microwave power115W, microwave time40s, concentration of alcohol80%, and the extration of procyanidins content was106.936mg/g. In the enzymatic extraction experiment, the results showed that the reaction conditions were temperature45℃, pH4.0, hydrolysis time1.0h, enzyme concentration100u/mg, and the extration of procyanidins content was87.513mg/g.Through the static adsorption experiments,5types of macroporous absorbent resins with different polarities were choosen for the best one. The result showed that an AB-8resin had a better adsorption (78.00%) and desorption (92.42%) properties than four other resins examined. The best adsorption condition was found to be3mg/mL procyanidins concentration with a flow rate of3BV/h, and the final adsorption rate was78.19%. The optimal desorption condition was found to be a flow rate of2BV/h using100mL of30%ethanol, and the final desorption rate of proanthocyanidins was92.37%. With the method of freeze-dried,10%-50%ethanol and other impurity of the mixture were removed, and the purity of the proanthocyanidins were determined to be85.16%.The samples of studying the antioxidant activity were different. They were crude extracts (GSPO), procyanidins solution mixed with25%ethanol (GSP1),50%ethanol (GSP2) and procyanidins powder after freeze-dried (GSP3).1. Procyanidins could effectively scavenge OH compared with Vc. The scavenging activity of four different samples was GSP3, Vc, GSP2, GSP1, GSPO, and when the concentration of procyanidins overed2.3mg/mL, the scavenging activity of Vc was stronger than GSP3.2. The O2·-radical-scavenging activity had a regative correlation with the concentration of procyanidins. And the scavenging activity of four different samples was GSP3, GSP2, GSP1, GSPO, Vc.3. The result of reducing power experment showed that the reducing power had a regative correlation with the concentration of procyanidins, and the relationship between them was GSP0> GSP1> GSP3> GSP2> Vc.4. Compared with the sample not added oil, procyanidins could inhibit peroxidation of lard and lipid. The POV of animal oil was64.22meq/kg (the control was144.83meq/kg), and the POV of vegetable oil was433.31meq/kg (control was573.72meq/kg). And the effect of protecting animal oil from peroxidating was much better than the vegetable oil.5. In the experment of DPPH scavenging effect of proanthocyanidins by ESR, the scavenging ability of them was GSP3, GSPO, GSP2, GSP1. The scavenging effect had a regative correlation with the concentration of procyanidins, and compared with low concentrations of procyanidins, the other was more efficient on DPPH scavenging effect.