Rapid test for detecting artificial colorants in wine products

Abstract

The problem of wine color adulteration is relevant all over the world, and, therefore, establishing or refuting the fact of the colorant presence is an integral part of the techno-chemical control. There are many methods for determining artificial colorants (AC) in the alcoholic beverages with various levels of sensitivity and selectivity of detection as well as the promptness in generating the results and the cost of studying one sample. Current work is devoted to the development of a rapid test for detecting the artificial colorants in wines. It is based on the method of the International Organization of Vine and Wine, the principle of which is to fixate the acidic artificial colorants on a specially prepared woolen thread when boiling the sample of wine. The modification of analytical procedure included the reduction of the test sample aliquot, the number of operations and the examination time without compromising the reliability of the conclusion. In order to imitate the color of red wines, Azorubine (E122), Allura Red AC (E129) and Indigo Carmine (E132) food colorants were used. The objects of the research were: model systems based on wine, white and red wines, counterfeit wines provided by the controlling authorities, and concentrated grape must. It was shown that in the genuine wines, depending on the color saturation of the test sample caused by natural anthocyanins, the woolen thread was discoloring from light to dark beige; its color was enhancing from pale pink to deep ruby with the increase in the content of AC in wine. The sensitivity of the proposed method made it possible to determine the presence of AC at the rate of 0.1-0.2 mg/dm3 in wines. The method did not require expensive equipment and could be used in the laboratories of winemaking industry or by the controlling authorities for establishing the fact of adulteration of alcoholic and juice products.