Effect of extraction conditions on pectin yield extracted from sweet potato peels residues using hydrochloric acid

Abstract

Pectins are complex polysaccharides obtained from higher plants which are structurally composed mainly of α-1, 4-linked-D-galacturonic acid (Gal A). Pectin has a good property of gelling, thickening and emulsification thus it is used widely in food and beverage industry. The applications of pectin in food industry are developing thus the demand of pectin is also increasing. Sweet potato residue is a potential local source of pectin. The peels of sweet potato are usually discarded prior to the consumption of the fruit. In Malaysia, starch industries and small local business are generating a lot of residual waste from sweet potato. Converting the waste into a value-Added product such as pectin would bring great advantage in term of environmental concern and profit. Effects of extraction conditions such as extraction temperature (60 - 100 °C), extraction time (60 - 180 min) and solution pH (1 - 3) on the extraction yield of pectin (%) from sweet potato residues were investigated in this study. The extracting solvent used was hydrochloric acid. The highest yield was 2.59 % which was obtained at extraction temperature 90 °C, extraction time 60 min and solution pH 1.5. All three extraction conditions showed significant effect on the yield of pectin (%).