TO THE EDITOR: The article titled “Sugar Content of Popular Sweetened Beverages Based on Objective Laboratory Analysis: Focus on Fructose Content” by Ventura et al. indicate that 42 and 55 high-fructose corn syrup (HFCS) are composed of either 42 or 55% fructose with the remaining percentage of glucose (1). In the study they analyze 23 samples of sweetened beverage samples and report finding a mean level of fructose of 59% instead of 55%. They also reported finding no maltose or other higher sugars in the samples. The method used for this analysis was AOAC 977.20.
AOAC 977.20 is a method designed to separate sucrose, fructose, and glucose in honey. Although it is a good method for identifying levels of these sugars in solutions of sucrose or invert sugar as the sweetener source, the method is not sufficiently sensitive to accurately identify maltose or higher sugars if they are present.
It is well known and part of the Code of Federal Regulations 21 CFR Sec. 184.1866 that HFCS shall conform to the identity and specifications listed in ref. (2). This HFCS monograph in Codex describes 42% HFCS as containing not <92% monosaccharides and not >8% other saccharides while 55% HFCS shall contain not <95% monosaccharides and not >5% other saccharides.
Early work done by Wartman et al. (3,4,5) also identified the levels of these higher sugars present in HFCS. The studies done by Wartman and her colleagues clearly identify levels of higher sugars in 42% HFCS and in 55% HFCS. The ratios of sugar identified in the early work by Wartman are used today to prepare standards for saccharide analysis. One of the more common methods for analysis of HFCS is AOAC 979.23 (saccharides in corn syrup).
It was apparent that if a method selected that was not validated for the detection of maltose or higher sugars the results of an analysis of saccharide distribution would be inaccurate. To verify this, the International Society of Beverage Technologists looked at a series of commercial 42 and 55 HFCS samples which were analyzed by Krueger Food Laboratories, a private contract company.
Six samples of 55 HFCS were measured in duplicate by AOAC 979.23. The results of this analysis were an average of 55.9% fructose, 39.9% glucose, and 4.2% higher sugars. The same samples measured by AOAC 977.20 averaged 58.0% fructose, 40.9% glucose, and 1.1% maltose. It should be noted that although the method is not validated for maltose, occasionally a peak will be reported. This peak was not consistent even in duplicate runs. When looking at the samples showing only fructose and glucose, the average fructose level was 58.5% with a glucose level of 41.5%.
Likewise, the average of six samples of 42% HFCS was 43.2% fructose, 51.4% glucose, and 5.4% higher sugars when analyzed with AOAC 979.23 and were 44.5% fructose, 53.9% glucose, and 1.6% higher sugars when analyzed with AOAC 977.20. The average result of the AOAC 977.20 samples showing no higher sugars was 45.1% fructose and 54.9% glucose.
It is apparent from these results that analyzing solutions-containing HFCS using AOAC 977.20 will falsely inflate the apparent proportions of fructose and dextrose present compared to AOAC 979.23 which is validated to measure higher sugars in corn sweeteners. Whereas no beverage samples were analyzed during this study one would have to suspect that analysis done with a method that measured fructose and glucose to the exclusion of maltose and higher sugars would also result in artificially high levels of fructose and glucose.