OAT BETA-GLUCAN AND XYLAN HYDROLYSATES AS SELECTIVE SUBSTRATES FOR BIFIDOBACTERIUM AND LACTOBACILLUS STRAINS

Novel oligomers that resist digestion in the upper gut were prepared f rom oat mixed-linked beta-glucan and xylan by enzymatic hydrolysis wit h lichenase of Bacillus subtilis and xylanase of Trichoderma reesei re spectively. The low-molecular-mass hydrolysis products of P-glucan and xylan were compared with fructooligomers and raffinose in their abili ty to provide growth substrates for probiotic (Lactobacillus and Bifid obacterium) and intestinal (Bacteroides, Clostridium and Escherichia c oli) strains in vitro. A degradation profile of each carbohydrate and total sugar consumption were analysed with HPLC, and bacterial growth rate with an automatic turbidometer, the Bioscreen C system. beta-Gluc ooligomers and xylooligomers both enhanced the growth of health-promot ing probiotic strains as compared with intestinal bacterial growth, bu t not to a significant level. Raffinose stimulated the probiotic strai ns significantly, whereas fructooligomers induced high average growth for intestinal bacteria also.