Analys av tanniner : från granbarksextrakt

Sammanfattning: The objective for this master’s thesis was to test and evaluate two methods for determining the content of tannin in a pinebarkextract. The methods used at Södra for this previously have not been specific enough, only the amount of polyphenolics have been measured. One of these methods is a test based on the Stiasny test and it determines the extracts ability to form a gel with formaldehyde. When this test was carried out it showed that the extract did not contain much tannin. The other method used at Södra measures the amount of polyphenolic substances with a spectrophotometer. The result from this method showed that the content were 50 %.   One of the two new methods that were evaluated determines the amount tannin present in the extract because of tannins ability to form a complex with proteins. According to this method, the amount tannin in the extract were 42,5 %, and 19,4 % of this in the form of tannic acid. These results are credible on basis of previous information about the extract.   The other method uses a RP- HPLC where ellagic and gallic acid were used as standards. The amount ellagic acid in the extract was determined to 0,06 %, but the result from gallic acid was inconclusive. Further analysis is necessary to evaluate the obtained results and the methods reliability.   If the metods is to be used on a regular basis, my recommendation would be to start evaluating the protein-binding method because this would be easier and less time-consuming than modifying the HPLC- method. The HPLC- method could on the other hand provide useful information about the extract, not only the amount tannin could be measured, but also which kind of tannin could be investigated.