International Journal of Food Microbiology 45 (1998) 163–169 Short communication Oat bran b-gluco- and xylo-oligosaccharides as fermentative substrates for lactic acid bacteria * Pia Kontula , Atte von Wright, Tiina Mattila-Sandholm VTT Biotechnology and Food Research, Tietotie 2, Espoo, P.O. Box 1501, FIN-02044 VTT, Finland Received 5 June 1998; received in revised form 20 July 1998; accepted 15 September 1998 Abstract The influence of oat bran oligosaccharides on carbohydrate utilization and fermentation end-products was studied with reference to three different lactic acid bacteria (LAB: Lactobacillus rhamnosus, Lactobacillus plantarum and Lactococcus lactis). The main results were that all three LAB utilized oat b-gluco-oligosaccharides, while only L. plantarum utilized xylo-oligosaccharides. The main products of LAB metabolism were lactic acid, acetic acid, formic acid and ethanol. The results indicated that oat b-gluco-oligosaccharides and xylo-oligosaccharides induce LAB to form the end-products of a typical mixed-acid fermentation. The formation of mixed-acid production from xylo-oligosaccharides was mainly due to the starvation of cells. This study indicates that oat bran oligosaccharides affect both qualitatively and quantitatively the fermentation end-products of LAB grown on these substrates. This should be taken into account when selecting strains for new fermented cereal based food products.  1998 Elsevier Science B.V. All rights reserved. Keywords: Oat bran oligosaccharides; Lactic acid bacteria; Fermentation end-products 1. Introduction molar ratio of acetate by 11% and increase the molar ratios of propionate and butyrate by 58% and 5%, Oat fibre has been indicated as a substrate (pre- respectively, although the effects on acetate levels biotic) for lactic acid bacteria (LAB). Throughout in were not observed in vivo (Cummings, 1995). vitro experiments, Lactobacillus rhamnosus GG has Acetate and propionate affect human cholesterol been shown to preferentially utilize oat-derived b- production, with propionate being gluconeogenetic gluco-oligosaccharides (Jaskari et al., 1998) and to (Wolever et al., 1991). Butyrate has been suggested effectively colonize the simulated human intestinal to prevent the proliferation of gut epithelial cells, microbial ecosystem as a result of oat bran feeding thus arresting the development of cancer (Csordas, (Kontula et al., 1998). Other in vitro studies with 1995). Recently LAB-fermented cereal products human stool have shown that oat can decrease the have been introduced into the market with the aim to combine the beneficial effects of oat fibre to the * probiotic action of certain LAB-strains (Salovaara, Corresponding author. Tel.: 1 358-9-456-5998; fax: 1 358-9- 455-2028; e-mail Pia.Kontula@vtt.fi 1996). 0168-1605 / 98 / $ – see front matter  1998 Elsevier Science B.V. All rights reserved. PII: S0168-1605(98)00156-1