Reduction of non-digestible oligosaccharides in soymilk by Lactobacillus fermentum CRL 722

LEBLANC, J.G.; GARRO, M.; SILVESTRONI, A.; CONNES, C.; PIARD, J.-C.; SAVOY DE GIORI, G.; SESMA, F.

Florianopolis, Brasil

Congreso; XXII Congreso Brasileira de Microbiologia; 2003

Human consumption of soy-derived products has been hampered by the presence of nondigestible oligosaccharides (NDO) such as the a-oligosaccharides raffinose and stachyose. Since mammals lack a-galactosidase (a-gal) which is necessary for the hydrolysis of these sugars, such NDO can be fermented by gasogenic microorganisms found in the large intestine (mostly in the cecum) which in turn can induce gastrointestinal disorders in sensitive individuals. We propose the use of lactic acid bacteria (LAB) with high levels of a-gal in order to increase the digestibility of the NDO so that they are eliminated before reaching the large intestine. In this study, the capacity of Lactobacillus fermentum CRL 722 to properly eliminate raffinose was studied in vitro using controlled fermentation conditions and in vivo using a rat model. L. fermentum CRL 722 was not only able to grow on commercial soymilk, but was also able to completely eliminate raffinose during fermentation due its high a-gal activity. Conventional rats fed soymilk fermented by this LAB had lower levels of a-gal in the cecum compared to rats fed unfermented soymilk, showing that the microbiota of these animals, which includes gasogenic microorganisms, is not in the presence of NDO. Since L. fermentum CRL 722 is able to eliminate NDO, this LAB could thus be used in the elaboration of novel fermented soy-based products with higher nutritional values.