CONTENT OF GALLIC ACID IN SELECTED PLANT EXTRACTS

Ethanolic extracts of phenolic compounds were prepared from green teas (Camellia sinensis L.), bearberry leaves (Arctostaphylos uva-ursi L.), hazelnuts (Corylus avellana), evening primrose (Oenothera biennis) and grape seeds (Vitis vinifera L.). All crude extracts were examined for their gallic acid content by HPLC. The bearberry-leaf preparation was also fractionated by a Sephadex LH-20 column chromatographic method with 95% (v/v) ethanol and acetone:water (1:1; v/v) as mobile phases: one fraction consisted of low molecular-weight phenolics and the other of tannins. To all samples tannase was applied in an effort to liberate gallic acid from the phenolic esters and hydrolysable tannins. The content of free gallic acid in the extracts ranged from 1 to 15 mg/g with the highest quantity being found in evening primrose. The content of gallic acid liberated by tannase ranged from 5 to 309 mg/g with the highest content being found in the tannin fraction from the bearberry-leaf extract.

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EVALUATION OF ASTRINGENCY OF PREPARATIONS WITH DIFFERENT DEGREE

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eISSN:	2083-6007
ISSN:	1230-0322

W latach 2022-2024 kwartalnik naukowy Polish Journal of Food and Nutrition Sciences realizuje projekt nr RCN/SP/0520/2021/1 finansowany ze środków budżetu państwa – Ministerstwo Edukacji i Nauki w ramach programu „Rozwój czasopism naukowych”. Dofinansowanie wynosi 120 000 zł. W ramach projektu podejmowane są działania zmierzające do podniesienia poziomu praktyk wydawniczych i edytorskich, zwiększenia wpływu czasopism na rozwój nauki oraz utrzymania się czasopism w międzynarodowym obiegu naukowym.

In the years 2022-2024, the scientific quarterly Polish Journal of Food and Nutrition Sciences accomplishes a project no. RCN/SP/0520/2021/1 financed from the state budged – Ministry of Education and Science Republic of Poland in the framework of a program “Development of scientific journals”. The financing amounts to 120,000 PLN. The program aims at improving the level of publishing and editing practices, increasing the impact of scientific journals on science development, and extending the international range of scientific journals.