Rapid Method for Sugar Analysis of Doughs and Baked Products

Cereal Chem. 72(4):349-351 A high-performance liquid chromatography (HPLC) method has been systems and one chemically leavened dough system were used to test developed to extract and quantitate individual sugars present in dough the methodology. The chemically leavened dough system remained consystems throughout processing. Sugars were extracted from freeze-dried stant in its sugar composition throughout processing. In all of the fersamples by boiling in 60% ethanol (v/v). No defatting of samples was mented systems, sucrose was hydrolyzed to fructose and glucose during required. All sugars (fructose, glucose, sucrose, maltose, and lactose) were mixing. Glucose was utilized preferentially by the yeast. Maltose was separated in 12 min using an aminopropyl 4-tim column and a 75:25 solution utilized upon depletion of fructose and glucose, as in the sponge fermentaof acetonitrile and water mobile phase. Sodium chloride (0.125%, w/v) tion. Lactose, when present, remained constant throughout the processing was incorporated into the mobile phase to eliminate refractive index interstages. ference from salt contained in the samples. Three different yeasted dough The mandate of nutrition labeling by the Food and Drug Administration (FDA) in 1993 has made sugar analysis (monoand disaccharides) a necessity for all of the food industry. Previous reports on sugar analysis of various food products were based on the total sugar or sucrose, with little emphasis on the other individual sugars. Colorimetric and iodometric methods (Somogyi 1952, Ting 1956) were unable to quantitate individual sugars. Gas-liquid chromatography (GLC) has been successful in determining individual sugars, but it requires a derivatization procedure (Li et al 1985). Recently, high-performance liquid chromatography (HPLC) has become the preferred method for quantitating simple sugars in a variety of food products (Zygmunt 1982, Picha 1985, Kwak and Jeon 1988, Potus et al 1994). Sample preparation varies depending on the food product in question. High-fat samples, such as chocolates, require defatting before analysis. High-fat samples have been pretreated by various methods, including boiling water (AACC 1983), a Carrez reagent (Bugner and Feinberg 1992), or a petroleum ether wash (AOAC 1990). Extraction methods for other food products include boiling in 80% ethanol (Picha 1985), 50% alcohol in an 80-85 C water bath (Zygmunt 1982), or a water extraction (AACC 1983). Li et al (1985) extracted samples using hexane followed by water or 80% ethanol. The objectives of our study were to develop an uncomplicated and rapid HPLC method for quantitating individual sugars, particularly in various fermented products, and to monitor those sugars throughout the baking process. MATERIALS AND METHODS Product Formulation, Preparation, and Sampling Four products were made: baking powder biscuits, spongeand-dough white pan bread, straight-dough white pan bread, and no-time white pan bread. Standard research formulas from the American Institute of Baking Experimental Baking Group were used (Rogers and Langemeier 1995). Product sampling protocols were followed to pinpoint gradual, as well as potentially sudden, changes in sugar content, with doughs being frozen in liquid nitrogen. Samples were held at -20° C before being freeze-dried. Sample weights were carefully monitored at each stage. All results were corrected to as-consumed basis. Sugar Extraction Dried samples were ground through a 40-mesh screen (Wiley Jr. Mills, Arthur Thomas Co. Scientific Apparatus, Philadelphia, PA) and analyzed for moisture content (AACC 1983). Aliquots 'American Institute of Baking, Manhattan, KS.