Optimization of Pectin Extraction from Peel of Dragon Fruit (Hylocereus polyrhizus)

Abstract

Dragon fruit is a popular fruit grown in Malaysia. In order to increase profits for dragon fruit growers and processors, dragon fruit peels, a by-product of dragon fruit processing, were investigated as a source of pectin. Pectin extraction was optimized from this by-product. Pectin was extracted under various conditions: pH 2 to 5; Ethanol Ratios (ER) from 1:0.5 to 1:3.5 and extraction periods 30 to 120 min. The highest yield was obtained after 120 min of extraction at pH 3.5, with ER of 0.5. Preliminary characterization of pectin, in terms of degree of esterification (DE) was also carried out in order to investigate the influence of different extraction conditions on the chemical composition of the extracts. Pectin with high DE was obtained at pH 5. The results imply that dragon fruit peels could be a substantial source in food production.