The aim of the present paper is to review the effects of non-digestible oligosaccharides (NDO) on immunity, focusing on their microbiota-independent mechanisms of action, as well as to explore their potential beneficial role in inflammatory bowel diseases (IBD). IBD are chronic, inflammatory conditions of the gastrointestinal tract. Individuals with IBD have an aberrant immune response to commensal microbiota, resulting in extensive mucosal inflammation and increased intestinal permeability. NDO are prebiotic fibres well known for their role in supporting intestinal health through modulation of the gut microbiota. NDO reach the colon intact and are fermented by commensal bacteria, resulting in the production of SCFA with immunomodulatory properties. In disease states characterised by increased gut permeability, prebiotics may also bypass the gut barrier and directly interact with intestinal and systemic immune cells, as demonstrated in patients with IBD and in infants with an immature gut. In vitro models show that fructooligosaccharides, inulin and galactooligosaccharides exert microbiota-independent effects on immunity by binding to toll-like receptors on monocytes, macrophages and intestinal epithelial cells and by modulating cytokine production and immune cell maturation. Moreover, animal models and human supplementation studies demonstrate that some prebiotics, including inulin and lactulose, might reduce intestinal inflammation and IBD symptoms. Although there are convincing preliminary data to support NDO as immunomodulators in the management of IBD, their mechanisms of action are still unclear and larger standardised studies need to be performed using a wider range of prebiotics.

This research paper aimed to evaluate the role of inulin as a fat replacer on the quality of Frescal sheep milk cheese. Sheep milk and its derivatives are a promising niche in the dairy industry, mainly due to increasing interest of consumers in diversified products. Three Frescal sheep milk cheese formulations, namely whole milk cheese (WMC), semi-skimmed cheese (SSC) and semi-skimmed cheese with 5 g/100 g inulin (SSCI) were prepared. Their composition was evaluated and the feasibility of using inulin as a fat substitute was investigated. SSC and SSCI were considered ‘reduced fat’ or ‘reduced calorie’ products. The addition of inulin to SSCI cheeses yielded textural parameters (firmness, adhesiveness, cohesiveness, and gumminess) with intermediate characteristics between SSC and WMC. All the formulations presented scores higher than 7.6 in sensory analysis. In conclusion, the use of inulin in semi-skimmed sheep cheese allowed the production of cheese with texturizing properties similar to whole milk sheep cheese, enabling the development of a foodstuff with lower caloric content and beneficial characteristics valued by consumers.

Equol, a derivative of daidzein produced by enterobacteria, has greater activity as a phyto-oestrogen compared with daidzein. Difructose anhydride III (DFAIII) is a newly manufactured non-digestible disaccharide with unique fermentation properties. The present study evaluated the prebiotic effects of DFAIII on equol production and on plasma cholesterol concentrations related to the changes in equol production. We compared plasma equol concentrations at 10.00 and 18.00 hours and faecal isoflavone excretion in three groups of seven rats (male Wistar-ST strain, 6 weeks old) fed a basal diet or a DFAIII or fructooligosaccharide (15/g diet) diet containing 1g soya isoflavone/g diet for 20d. Equol concentrations in the DFAIII group were higher than in the control and fructooligosaccharides groups, especially in the later phase of the light period (18.00 hours) throughout the experiment. Daizein and genistein concentrations did not change between the diet groups. The faecal ratios of equol:daidzein were very high in all groups, but the ratios were higher in the DFAIII group than the control and fructooligosaccharide groups on day 3, and this tendency continued throughout the experiment. On day 20, the plasma total cholesterol concentration was lowest in the DFAIII group. Additionally, the cholesterol concentrations were inversely correlated to plasma equol concentration in all the rats. In conclusion, DFAIII efficiently enhanced plasma equol concentrations, which may be associated with an increase in equol production and a decrease in equol degradation by enterobacteria. Higher plasma equol concentrations may contribute to the hypocholesterolaemic effect of DFAIII feeding.

The main role of diet is to provide enough nutrients to meet the requirements of a balanced diet, while giving the consumer a feeling of satisfaction and well-being. The most recent knowledge in bioscience supports the hypothesis that diet also controls and modulates various functions in the body, and, in doing so, contributes to the state of good health necessary to reduce the risk of some diseases. It is such an hypothesis which is at the origin both of the concept of ‘functional food’ and the development of a new scientific discipline of ‘functional food science’. In the context of this paper the potential ‘functional foods’ to be discussed are the prebiotics and the synbiotics. The prebiotics developed so far are the non-digestible oligosaccharides and especially the non-digestible fructans among which chicory fructans play a major role. The chicory fructans are β (2-1) fructo-oligosaccharides classified as natural food ingredients. They positively affect various physiological functions in such a way that they are already or may, in the future, be classified as functional food ingredients for which claims of functional effects or of disease risk reduction might become authorized. They are classified as prebiotic and have been shown to induce an increase in the number of bifidobacteria in human faecal flora. As part of a synbiotic-type product, they are already bifidogenic at a dose of 2·75 g/d and the effect lasts for at least 7 weeks. The other potential functional effects are on the bioavailability of minerals, but also, and more systemically, on the metabolism of lipids. Potential health benefits may concern reduction of the risk of intestinal infectious diseases, cardiovascular disease, non-insulin-dependent diabetes, obesity, osteoporosis and cancer. However, except for the prebiotic effect, and tentatively the improvement of calcium bioavailability, the evidence to support such effects is still missing in humans though hypotheses already exist to justify nutrition studies.