Determination of Carbonyl Compounds in Alcoholic Beverages

Abstract

Highly sensitive methods to determine carbonyl compounds in alcoholic beverages including moromi which contains high concentrations of corbonyl compounds, were investigated.
In analysis of acetion (AC) and diacetyl (DA), a test sample was first perpared for 2, 4-dinitrophenylhydrazine (DNPH) derivatives by adding 1ml of a solution of 500mg DNPH per 100 ml instead of 1ml of a solution of 50 mg per 100ml to 1ml of a test sample.The reaction proceeded for 60 min.Right away, the DNPH derivatives of the carbonyl compounds were determined by HPLC.Averages of recovery were observed to be 99.5% for AC and 95.0% for DA.Coefficients of variation were within 3.7%for AC and 4.5% for DA.Minimum detectable concentration was 0.05mg per 1 for AC and DA.
Acetolactate (AL) was determined by subtracting DA value befere heat oxidation from DA value after the oxidation at 60°C for 60 min.
This procedure was shown to be applicable to moromi and beer as well as others.In white wine and some kinds of red wine, acetaldenyde (AA) gave one fourth of those determined with the enzymatic method such as F-kit of Boehringer & Mannheim.It turned out that sulfurous acid in the alcholoic beverages affected the reaction with DNPH but did not the enzymatic reaction, In the enzymtic method, an average recovery was 99.5% and a coefficient of variation was 1.8% to 2.9%.Minimum detectable concentration was O.05mg AA per 1.
These results indicate that AC, DA and AL in alcoholic beverages would be determined with HPLC method after preparation of DNPH derivatives and AA with the enzymatic method.