Comparative study on the monosaccharides of three typical galactomannans hydrolyzed by different methods

Abstract

The factors affecting the hydrolysis of galactomannans, Gleditsia Sinensis gum, guar gum, and fenugreek gum, have been compared and optimized with three different methods. The obtaining of galactose and mannose in the galactomannans were determined using high-performance liquid chromatography, and the yield of the one-step hydrolysis was significantly higher than that of the two-step hydrolysis. Specifically, the two-step acid hydrolysis of Gleditsia Sinensis gum, guar gum, and fenugreek gum yielded the monosaccharides at 85.28 %%, 85.40 %, and 87.69 %, respectively, which resulted in a relatively low recovery of hydrolysis yields. Conversely, the one-step hydrolysis of Gleditsia Sinensis gum, guar gum, and fenugreek gum under the optimum conditions yielded the monosaccharides at 95.18 %, 93.47 %, and 93.50 %, respectively. The maximum yield of monosaccharides was not achieved by acid hydrolysis under drastic conditions or mild chemical hydrolysis. The production and degradation of galactose proceeded slightly more easily than that of mannose. Furthermore, the mannose-to-galactose ratios of the studied galactomannans were compared using nuclear magnetic resonance. The determination and characterization of Gleditsia Sinensis gum, guar gum, and fenugreek gum using three different treatments to understand the effect of different acids on galactomannan hydrolysis properties is of great significance.