Enzymic Determination of Primary Normal Alcohols as Apparent Ethanol Content in Honey

Abstract

Primary normal alcohols of 33 unpasteurized Galician (northwestern Spain) honeys have been determined as apparent ethanol contents. A modification of the Boehringer-Mannheim enzymatic method has been used. The solution of honey has been employed directly, neither clarified nor neutralized. Removal of interferences required absorbance measurements at 340 nm, by using the solution of honey with the solution of aldehyde dehydrogenase into the reference cuvette. Water is added to the reference cuvette and alcohol dehydrogenase suspension to the sample cuvette. The blanks are measured following the same procedure with redistilled water instead of sample solution. Ten replicate analyses of each of four samples with apparent ethanol levels of 13.5,35.3, 50.1, and 141.8 mgkg gave coefficient of variations of 1.74%, 0.48%, 0.34%, and 0.22%, respectively. The modified enzymatic method performed well in recovery experiments (recovery 100.1%). The apparent ethanol contents of 32 of the 33 honeys studied lay in the range 13.5-50.1 mgkg (mean 27.8 mgl kg); the remaining unspoiled honey had an apparent ethanol content of 141.8 mgkg.