The carbohydrate analysis of HFCS is based on methods which first hydrolyze the syrup into simple sugars before quantitative analysis. We have examined whether HFCS can be hydrolyzed under the same conditions suitable for hydrolyzing sucrose. A new GC/MS method for the quantitation of fructose and glucose as their methoxyamine derivatives and 13C labeled recovery standards was used to determine the carbohydrate content of HFCS in 10 commercial beverages. Samples were analyzed before and after acid hydrolysis. The carbohydrate contents in commercial beverages determined without acid hydrolysis were in agreement with the carbohydrate contents provided on the food labels. However, the carbohydrate contents of beverages determined after acid hydrolysis were substantially (4–5 fold) higher than the listed values of carbohydrates. As fructose and glucose in HFCS may exist as monosaccharides, disaccharides and/or oligosaccharides, analysis of the carbohydrate content of HFCS containing samples may yield widely different results depending on the degree of hydrolysis of the oligosaccharides. With inclusion of mild acid hydrolysis, all samples showed significantly higher fructose and glucose content than the listed values of carbohydrates on the nutrition labels. The underestimation of carbohydrate content in beverages may be a contributing factor in the development of obesity in children.
