CHAPTER 13:Analysis of Dietary Sugars in Beverages by Gas Chromatography

Gas chromatographic methods, including sample preparation, derivatization and analysis for the characterization of carbohydrates in alcoholic (beer, wine and spirits) and non-alcoholic (juices, soft drinks and hot drinks) beverages are described in detail in this chapter. In general, beverages are composed by low molecular weight carbohydrates (LMWC), oligosaccharides and polysaccharides. Although GC analyses are mainly orientated to the determination of LMWC, structural analysis of oligo- and polysaccharides combining both derivatization and hydrolytic procedures can be done. Derivatization procedures based on the formation of trimethylsilyl and trimethylsilyl oxime derivatives are commonly used for the analysis of carbohydrates in beverages, although other procedures such as acetylation have also been considered. These compounds are detected by flame ionization detectors (FID), although coupling of GC to mass spectrometry (MS) can provide useful data for the determination of the chemical structure of carbohydrates. Both qualitative and quantitative data of the individual carbohydrates present in beverages can be obtained by GC.