Les levures et les bactéries lactiques impliquées dans les bières traditionnelles à base de sorgho produites en Afrique subsaharienne (synthèse bibliographique)

Abstract

Yeast and lactic acid bacteria involved in traditional sorghum beer produced in sub-Saharan Africa. A review. Sorghum beer produced in sub-Saharan Africa contributes significantly to the diet of the population. The production process of sorghum beer, however, remains empirical and varies from one region to another, leading to several types of sorghum beer. Furthermore, the production process involves several steps, including a fermentation step composed of uncontrolled lactic and alcoholic fermentations. This review summarizes the current state of scientific knowledge on lactic acid bacteria and yeasts involved in sorghum beers in sub-Saharan Africa and their use as starter cultures. Lactic fermentation, which is mainly carried out by lactic acid bacteria belonging to the genus Lactobacillus, primarily Lactobacillus plantarum and Lactobacillus fermentum, allows the production of organic acids, aromatic compounds, yeast growth stimulation and the inhibition of pathogens. The alcoholic fermentation is dominated by Saccharomyces cerevisiae with proportions sometimes reaching up to 99%. The main function of S. cerevisiae is to transform fermentable sugars into alcohol and carbon dioxide. Strains of S. cerevisiae isolated from sorghum beers show phenotypic and molecular differences from the type species S. cerevisiae CBS1171. In order to improve and control sorghum beer production in sub-Saharan Africa, especially the fermentation stage (lactic and alcoholic fermentations), the use of starter cultures of yeast and/or lactic acid bacteria were tested. Beer obtained from inoculation tests with these starters showed organoleptic and sensory characteristics comparable to beer produced in the traditional way.

Keywords

• Saccharomyces cerevisiae
• lactic acid bacteria
• beers
• sorghum grain
• starter cultures
• lactic fermentation
• brewers'yeast