Studies On The Processes Of Extraction And Purification Of Grape Polyphenol And Its Antioxidation Capacity

Grape(Vitis vinifera L.) is one of the most widely cultivated plants in the world. China is rich in grape resource, both of its annul output and cultivated areas rank first in the world. It is reported that each year there are about80%of grapes used to brew wine, which leaves a large number of grape seeds without full utilization. Therefore, to commercially exploit this by-product is of great importance.Studies have found grape seeds contained a variety of chemical constituents with polyphenol accounted the most. Over the past years, studies have focused on the grape polyphenol and revealed many inspiring bioactivities. Grape polyphenol could efficiently scavenge free radicals in vivo and exerted excellent antioxidation activities, those activities provided preventative and therapeutic benefits against kinds of chronic diseases. So there is a promising prospect for grape polyphenol application in the healthcare and other fields. In this dissertation, grape seeds were subjected as raw materials to the extraction and purification of grape polyphenol, and those processes were optimized through systematical studies with indicator of grape polyphenol content. Additionally, antioxidation capacity of grape polyphenol were investigated in three different tests. The main researches results were stated as following:1. Folin-Ciocalteu colorimetry were introduced to determined the contents of polyphenol in grape seeds. Colorimetric conditions were systematically studied and the optimal ones were determined. Consequently, an accurate and reliable quality control standard was established under this optimal conditions.2. The key factors impacted polyphenol extraction were determined by single factor and orthogonal experiments with ethanol served as the extraction medium. An optimal extraction conditions were determined and the contents of polyphenol reached38.4%when grape seeds extracted under this conditions.3. To refine the extraction of grape seeds, the static-dynamic adsorption-desorption property of AB-8macro-porous adsorption resin and its serviceable times were investigated. An optimal refining conditions were determined and the contents of polyphenol was significantly increased to51.39%when extraction of grape seeds treated under this conditions.4. Different chromatography methods including macro-porous adsorption resin, Sephadex LH-20gel and preparative liquid chromatography were applied to the enrichment and purification of proanthocyanidin B2. Finally this compound was got with its purity more than95%.5. Antioxidation capacity of grape polyphenol in vitro were contrasted with that of vitamin C in three different tests, DPPH, hydroxyl and superoxide anion free radical scavenging experiments. Results shown a stronger antioxidation capacity of grape polyphenol than vitamin C, and an ideal dose-efficacy relationship of grape polyphenol was observed.