異性化糖中のマルチュロースの分析法

Abstract

Contamination of maltulose in high-fructose syrup is undesirable. To reduce this contamination in the final product, the conditions of enzymatic liquefaction of starch should be controlled to a minimum formation of this oligosaccharide. For selection of the suitable conditions, a reliable analytical method of maltulose and other oligosaccharides is necessary. We have tested paper chromatography to separate these oligosaccharides in two samples of the isomerized sugar syrup, which were obtained commercially and produced by treating maltose with strongly basic anion-exchange resin. Maltose (Rg =0.68) could be separated from maltulose (Rg =0.79) by using a solvent system of ethyl acetate/acetic acid/water (3 : 3 : 1, v/v), while isomaltose (Rg =0.64) was hardly separable from maltose under these conditions. By using a solvent system of n-butanol/pyridine/water (6:4:3, v/v), isomaltose (Rg =0.64) could be separated from maltose (Rg =0.73) and maltulose (Rg =0.73), both of which were unseparable each other. Therefore, a combination of the two paper chromatographic systems gives the complete separation of maltose, maltulose and isomaltose. The amounts of each sugar was measured by the anthrone method after extraction of appropriate area of paper with water. The complete separation of these oligosaccharides is also possible on either a liquid chromatography or a high-performance liquid chromatography. These methods are, however, impractical for our purpose, because it takes too long (11 hr) for the separation with the former apparatus and the column of the latter is easily deteriorated.