The Use of Cation-exchange Resins for the Hydrolysis of Sucrose in Plant Extracts

Abstract

Sucrose was completely hydrolyzed in 40 min. at the temp, of boiling water when stirred with a synthetic sulfonic acid-type cation-exchange resin. The reducing sugars formed during the hydrolysis were determined by the Somogyi titration method. Dowex-50 (Dow Chemical Co., Midland, Mich.), Amberlites IR-100 and IR-120 (Rohm and Haas Co., Philadelphia, Pa.) and Duolite C-3 (Chemical Process Co., Redwood City, Cal.) were equally effective for the resin hydrolysis. Melibiose, maltose, cellobiose, and turanose were not hydrolyzed by the resin treatment while raffinose and melezitose were partially hydrolyzed. Starch and inulin were treated separately with resin and HC1. No reducing sugars were formed from starch with either the resin or acid hydrolysis while the acid-hydrolyzed inulin titrated completely as reducing sugar, but from the resin treatment only a trace of reducing sugar was detected. The resin method was compared with HC1 and invertase methods for the determination of non-reducing sugars in tomato, tobacco, and barley extracts. All 3 methods gave similar results. The recovery of sucrose added to a plant extract was practically quantitative following the resin hydrolysis.