Sulfur Dioxide as a Stabilizing Agent of Local Beers from Kara City in Togo

Abstract

Beer is a drink consisting of an extremely complex mixture of over 3000 different compounds in an aqueous environment. In Togo, one of the most popular drinks is “Tchoukoutou”, a local beer made by fermenting sorghum. This sorghum beer, also popular in many African countries, is produced in a traditional way by women, often in unhygienic conditions. The production of this beer is not reproducible and also, lacks the necessary physicochemical, chemical and microbiological analyses to evaluate its quality. Moreover, because of its instability, it cannot currently be stored for more than 72 h. In this study, we used sulfur dioxide as a stabilizing agent for sorghum beer and studied its impact on certain physico-chemical and microbiological parameters. The parameters analyzed are pH by pH meter, density by areometry, volatile and total acidity by titrimetry, alcoholometry’s degree by densimetry, sugar content by enzymatic method, carbon dioxide rate by manometry and microbiological quality; the free and total SO₂ rate. The results show that sulfity (sulphity) samples are more acidic than those without SO₂. Thus, the pH values of the samples of «Tchoukoutou» are between 1.52±0.01 and 3.31±0.00; the density of the drinks varies between 1.0042±0.0002 and 1.0489±0.0001 g/cm. The total acidity of the Tchoukoutou studied varies between 1.54 and 4.30 g/L of H₂SO₄; the sugar content in the local beers analyzed varied between 26.1 and 93.2 mg/L. The fermentation process did not take place in the sulfity sample, confirmed by the alcohol content which is between 0 and 7.48% in the non sulfited; the CO₂ content varied between 359 and 653 mg/L. Microbiological analysis revealed that the sulfity samples were preserved from the microorganisms sought. We can retain from this study that the sulfity of Tchoukoutou beer can help prolong the quality of this local drink by inhibiting the growth of microorganisms causing deterioration of the organoleptic quality of Tchoukoutou.