Extraction of Tannin from Banana Peel

Abstract

Tannin was extracted form banana peels of Kluai Hom Tong, Kluai Nam-wa and Kluai Khai at different stages of ripeness. The result indicated that varieties and ripening stages affected the amount of tannin content. Kluai Hom Tong containes more tannin than Kluai Nam-wa (stages 1 and 3) and Kluai Khai (stages 1, 3 and 6). Green banana peels provided high level of tannin content and then decreased during the ripening process. Decreading rate of tannin inKluai Khai was quite high compared to the other ones. Tannin extraction from banana peels were carried out to determine the optimum condition such as type of solvents, extraction time, extraction temperature and ratio of banana peels to solvent. The recovery yield of tannin from one-time extraction was 81-85% of total tannin with 2 hrs soaking in 50% ethanol at 50°C and ratio of banana peels to solvent 1:30 or 1:40 w/v. Tannin was isolated and purified from the crude extracted of Kluai Nam-wa peel by adsorption chromatography on Sephadex LH-20. The brownish purified condensed tannin showed differences in their reactivity toward chemical reagents compared to hydrolyzable tannin as tannic acid. Condensed tannin also exhibited the ability to precipitate protein and metal ion.