a-Galactosidase activity was observed in six strains of Lactobacillus plantarurn isolated from fermented cereal products, human intestinal flora and fermented tea. The cultural conditions under which the enzyme activity was detected suggest that the enzyme is inducible. Development of mutants in four out of the six strains was observed and the mutants recorded high enzyme activity than the parent strains. Effect of different carbohydrates on enzyme activity showed glucose and raffinose being repressive in the parent strains. Although all the carbohydrate sources supported growth, highest amount of enzyme activity was recorded on lactose and glucose. The enzymatic potential of L. plantarum in reducing flatulence properties of the raw material base of some West African fermented foods is suggested.
Lactobacillus plantarum is a widely distributed lactic acid bacteria species involved in various fermented products such as milk, vegetables, meat and cereal grains. It is also frequently isolated from human intestinal mucosa.
Fermented products in sub-sahara Africa constitute a significant portion of the peoples diet. Various agricultural products are employed and the fermentation process is mostly the outcome of lactic acid bacteria -yeast interaction. Because the raw materials are usually starchy, different carbohydrates are present during products processes. The focus of this study are the oligosaccharides specially stachyose, raffinose and sucrose. They have been reported to be present in appreciable amounts in soybeans (SHALLENBERGER et al. 1967), sorghum grains (FAPARUSI 1970) and some leguminous plants used in the preparation of fermented seasoning agents (ODUNFA 1982).
Stachyose, a tetrasaccharide is believed to contribute to flatulent properties of some of the raw materials, thus making them not desirable for human consumption. However, if the sugar can be fermented to produce acid or hydrolysed to mono-and disaccharides by microorganisms, the products thus prepared ought to be less flatulent and more acceptable (MITAL et al. 1973).
Alpha-galactosidase (EC 3.2.1.22) is known to hydrolyse P-D-galactosidic bonds present in raffinose and stachyose, and have been reported to be present in many yeasts, moulds and plants (DEY and