Determination of Aflatoxins and Volatile Impurities in Alcoholic Beverages and their Raw Materials.

Abstract

The thesis is in two parts. The first part involved the analysis of aflatoxins in the alcoholic beverages and their raw materials. Thin Layer Chromatography (TLC) was used to determine the concentration of the aflatoxins. This was done by comparing colour intensities with those of the standards of known concentrations using a TLC densitometry. The highest concentration obtained was that of aflatoxin Bl (52.47 g/1) and was found in busaa, a common local brew prepared from fermented maize flour. Other opaque brews showed lower concentration of aflatoxins in the range of 2.19-42-82 g/1 for Bl, 0.25-2.24 g/1 for B2 and 0.56-14.63g/1for Gl. The clear-looking brews showed the absence of aflatoxins except kibuku root, which showed the presence of aflatoxin Bl in a concentration of 0.46 g/1.

The raw materials used in the preparation of these brews were found to contain aflatoxins with concentrations from 31.1-169.4g/Kg firs Bl, 11.3-56.4 g/Kg for B2, and 10.7-45.1 g/Kg for Gl. The concentrations of the aflatoxin Bl was found to be highest in maize flour (l69.4 g/1) as compared to millet and sorghum flour.

The second part of the thesis involved the analysis of volatile impurities in alcoholic beverages using Gas-Liquid Chromatography (GLC) technique. The brews analyzed showed the presence of n-propanol (4.50-84.88ppm), methanol (1,37-1798,70 ppm), ethy1 acetate (7.59-1176.44ppm), isobuty1 alcohol (4.49-147.64ppm), butanol (7.54ppm) and amyl alcohol (32.52-392.55 ppm). Pineapple wine was found to have the highest concentration of methanol (1798.70 ppm).