Partially hydrolyzed guar gum: Preparation and properties

Abstract

Guar gum is a galactomannan obtained from the endosperm portion of seed of the plant Cyamopsis tetragonolobus. Guar gum is used as thickener and stabilizer in food industry due to its high viscosity in aqueous solution. The partial hydrolysis of the guar galactomannan leads to production of partially hydrolyzed guar gum (PHGG) which is similar in structure to native guar galactomannan. PHGG can be produced by enzymatic hydrolysis, acid hydrolysis, irradiation, microwave and ultrasonication techniques. Enzymatic hydrolysis of guar gum is preferred for food processing applications. In enzymatic hydrolysis, enzymes such as mannanse, pectinase, cellulase cut the linkages between mannose units in the main chain. Partial hydrolysis of guar gum leads to the reduction in molecular weight of native guar gum. Partially hydrolyzed guar gum shows low viscosity in aqueous solutions. X-ray diffraction analysis of partially hydrolyzed guar gum revealed that it is little crystalline in nature as compared to native guar galactomannan which is amorphous in nature. Partially hydrolyzed guar gum produced from enzymatic hydrolysis can be used mainly for nutritional purpose i.e. for development of fiber enriched processed food products such as cookies, bread, noodles, yoghurt etc. Its specific physicochemical properties make it possible to improve the quality of food products. Partially hydrolyzed guar gum as soluble dietary fibre is beneficial in diabetes, heart disease and digestive problems.