growth of L. reuteri ATCC 23272. Lactobacillus rhamnosusGG ATCC 53103 grew to the highest OD on glucose comparedwith FOS and b-glucotriose. Lactobacillus curvatusFRP 15 and L. plantarum FRP 16 prefer oligosaccharidesover glucose in GOS and glucooligosaccharides. GOS werethe preferred sugar over monosaccharides in the growth ofP. acidilactici FRP 236. Bifidobacterium longum ATCC15707 grew better on FOS and GOS than on glucose. Basedon the results of our study, carbohydrate preferences of probioticbacteria are widely different even within a single straingiven the different types of prebiotics. But the report byAmaretti et al. (2007) that “monosaccharides were preferredover oligosaccharides in a few cases, while growth rates andcell yields were higher on oligosaccharides than on theirmonomeric moieties in many others” is still reliable. Thepreferential consumption of oligosaccharides of most probioticstrains (10 out of 12) can be an advantage for the strainsin their competition for nutrition with other microorganismsin the human gut, where oligosaccharides are the main sugars.The reduction in pH of culture medium in which thegrowth of probiotics is promoted illustrates that the SCFAsmay be produced. SCFAs are end products of prebiotics fermentationand are beneficial to human health, as they can decreasecolonic pH and inhibit non-acid-tolerant bacteria whilesupporting the growth of beneficial microbiota in gut. Theymay also contribute toward host energy requirements.Previous studies focussing on in vitro fermentation of inulinindicated that molecules with a chain length (DP) of >10are fermented on average half as quickly as molecules with aDP of <10 (Roberfroid et al. 1998). Sanz et al. (2005) reportedthat disaccharides with linkages of 1–2, 1–4, and 1–6generate a high prebiotic index. In our study, the fermentabilityof two types of prebiotics b(2–1) fructans and bglucooligosaccharidesappear to be determined by chainlength (DP); whereas, the fermentability of prebiotics withlinear chains consisting of galactose units (GOS-type) is notaffected by the chain length, which illustrates that linearchains consisting of galactose units are prone to be used byprobiotics compared with those consisting of glucose andfructose units. This structure–component–fermentability informationobtained in this study may lead to a predictiveunderstanding of how specific structures of prebiotics are fermentedby the human gut microbiota and may provide informationin the studies of dietary modulation of probioticbacteria. These results may also help to design new improvedprebiotic–probiotic preparations.
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