Effect of Time and Solvent/Feed Ratio on the Extraction of Mannan from Aloe Vera Leaf Pulp

Abstract

Mannan is one of oligosaccharides contained in the Aloe Vera leaf pulp gel, which exhibits promising potential as a raw material of edible coating due to its antimicrobial, antifungal, coating and drying properties. The objective of this work was to investigate the effect of time and solvent/feed ratio on the extraction of mannan from A. Vera leaf pulp. Extraction was carried out in a three necked flask equipped with mechanical agitator, Leibig condenser and thermometer. Two hundreds grams of A. Vera leaf pulp was juiced and the remaining pellet was then subjected to water extraction at 40oC and certain solvent/feed ratios for a specified time. Upon precipitation of A. Vera juice and supernatant by addition of ethanol, the precipitated extract was lyophilized and determined its mannan content. The optimum extraction time was found to be 45 minutes where reasonable yield and rendemen were obtained with highest extract purity. The optimum feed/solvent ratio was 4, where highest yield and rendemen were obtained at good extract purity. Hydrolysis was likely to happen when feed/solvent ratio higher than 4 as excess water at warm temperature causing reduction of extraction yield and rendemen. The proposed mathematical model suited the experimental data very well.