Enzymatic Determination of Galactose and Lactose in Honey

• Published in: Journal of agricultural and food chemistry Vol. 46; no. 4; pp. 1381 - 1385
• Main Authors: Val, A, Huidobro, J. F, Sánchez, M. P, Muniategui, S, Fernández-Muiño, M. A, Sancho, M. T
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.04.1998
• Subjects: ANALYTICAL METHODS; Biological and medical sciences; BOEHRINGER-MANNHEIM GMBH ENZYMATIC METHOD; CHEMICAL COMPOSITION; Confectionery products and chocolate industries, honey; Food industries; Fundamental and applied biological sciences. Psychology; GALACTOSE; HONEY; LACTOSE; MEASUREMENT; QUANTITATIVE ANALYSIS; Performance evaluation; Galactose 1-dehydrogenase; Enzyme; Honey; Enzymatic method; Absorption spectrometry; Lactose; Analysis method; Glycosidases; Hydrolases; Carbohydrate; Chemical composition; Oxidoreductases; Galactose; O-Glycosidases; β-Galactosidase; Quantitative analysis
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf970483z

Even when galactose and lactose are present in extraordinarily low concentrations in honey, both sugars are important constituents of this foodstuff because they might be useful in its characterization. Lactose and galactose determination in honey is also important because of the toxic effect of both sugars on honey bees. For the first time, a modification of the Boehringer-Mannheim GmbH enzymatic method is applied to 46 floral unpasteurized honeys for analyzing these sugars accurately, specifically, and quickly, with very low detection limits. Galactose is quantified directly without previous elution. The method avoids both previous chromatographic elution of mono- and disaccharides and removal of glucose. For galactose analysis pretreatment of honey solution with 0.5 mL of Carrez I, the same quantity of Carrez II, and 4 mL of 0.1 N NaOH is necessary; after filtration, 0.100 mL is used as sample solution, and galactose dehydrogenase is employed as enzyme. For simultaneous determination of galactose and lactose, not only is the previous clarification with Carrez solutions necessary, but neutralization with 1 mL of 0.1 N NaOH and 3 mL of 0.1 N KOH is also required. After the filtration, it is necessary to use 0.050 mL as sample solution and galactose dehydrogenase and β-galactosidase as enzymes. For a microtest, 0.99 mL final volume is required. Precision (%CV < 2.40 for galactose and <2.01 for lactose) and recovery (99.9% for galactose and 100.3% for lactose) were good. The galactose content of the honeys analyzed ranged between 0.0052 and 0.0151%. The lactose content of the honeys analyzed ranged between 0.0062 and 0.0383%. Keywords: Honey; galactose; lactose; enzymatic analysis