The Study Of Tannin's Extraction,Fractions And Characters From Rapeseed Shell

Vegetable tannin is a kind of abundant and important natural active material, which has various influence on the use and growth of plant. It is applied in petroleum and mining industry , architecture, chemical engineering, weaving, food, medicine and agriculture. More than 90% tannin exist in rapeseed shell, which takes about 12%~19% of the whole seed and is the main factor for its black appearance. Tannin is one of the antinutrional factor. This paper have studied the tannin in rapeseed shell, including its content and the influencing factors of extractional rate, and its optimized extraction way through orthogonality experiment. The original extraction is purified with different organic solvent and macroporous adorption resin. Its biological activity is also studied and analysed. Research results are as follows:1. Choosing ethanol aqueous solution to extract tannin, we find temperature is the most important factor which influences the extraction, the others respectively are: temperature >solvent pH value >solvent proportin >time. According to the knot of two orthogonality experiments we have determined the best extractive technology for tannin in rapeseed shell: 70 癈 , 40 min, the ethanol of 70% and pH3.0, which has better effect than the traditional technology by water.. Through repeating three times , the 97% tannin could be extracted.2. After handled with petroleum aether and chloroform, the article purity has raised 9.68%. Using ethyl acetate, water and methanol respectively, we can separate different kind tannin by the size of molecule preliminarily. Purified by the suitable resin with the 80% ethanol wash, adsorption rate is46.76mg/g, desorption rate is 31.99%, tannin's purity reaches77.39%.3. The ultraviolet scanning chromatograms show that all the different componets have biggest absorption at 280 nm, which is similar as the flavanol's adsorption. Analyzing the components by using RT-HPLC with 30% acetonitrile as mobile phase, we studied the retention time that the component in ethyl acetate has the longest time, using the Gel Perk Chromatography, we get the molecular weights of every component, which are M1=l 395.8, M2=2626.4, M3=2931.9. The resultshave explained the weight is bigger, the polarity is the more strong.4. With different organic solvent ,we can get groups of tannin with relatively different molecular weight in rapeseed shell. The tannin I in ethyl acetate which is about 4% of the total extractions is mainly 2-5 polymers. Presumed from the HPLC collections, the degree of polymerization(DP) of one of the tannin I which is about 70% of tannin I is 3, the other one is about 5. In tannin II, there are also two compositions . DP of the first composition Which takes 90% is about 9, the other one is about 5. In tannin m,one DP which takes about 30% is 10, the other one is 9.5. The tannin in 4 levels expression have difference antioxidation activity, and their sequence is: III > > II > I . We can find out tannin can still have synergism together with VE and EDTA, promoting the antioxidation effect.6. The tannin of different levels have great discrepancy in ability of binding with gelatin:III > original article> II > I . This result is consistent with its lipid antioxidation result. With identical quality , the tannin's ability of binding the gelatin differed along with the change of reaction system pH value. When pH value is about 4-5, the Rt value is much greater, which showed the most suitable pH value for tannin to bind with gelatin is 4~5, close to the isoelectric point of gelatin (pi = 4.7)7. he tannin in different levels and its sheet of reference specimen tannin acid in different pH condition under restrain bacterium performance difference, and its suitable pH is 4.0-5.0. All the tannin components in the mass concentration of 1.0 mg/ml have no restraining effect for Saccharomyces cerivisiae, Aspergillus niger, Rhizopus nigricans. In the test bacterium chosen the different tannin's restraining bacterium performance is in proper order: II > I > o...