Roberfroid M.,Catholic University of Louvain |
Gibson G.R.,University of Reading |
Hoyles L.,University of Reading |
McCartney A.L.,University of Reading |
And 17 more authors.
British Journal of Nutrition | Year: 2010
The different compartments of the gastrointestinal tract are inhabited by populations of micro-organisms. By far the most important predominant populations are in the colon where a true symbiosis with the host exists that is a key for well-being and health. For such a microbiota, normobiosis characterises a composition of the gut ecosystem in which micro-organisms with potential health benefits predominate in number over potentially harmful ones, in contrast to dysbiosis, in which one or a few potentially harmful micro-organisms are dominant, thus creating a disease-prone situation. The present document has been written by a group of both academic and industry experts (in the ILSI Europe Prebiotic Expert Group and Prebiotic Task Force, respectively). It does not aim to propose a new definition of a prebiotic nor to identify which food products are classified as prebiotic but rather to validate and expand the original idea of the prebiotic concept (that can be translated in prebiotic effects), defined as: The selective stimulation of growth and/or activity(ies) of one or a limited number of microbial genus(era)/species in the gut microbiota that confer(s) health benefits to the host. Thanks to the methodological and fundamental research of microbiologists, immense progress has very recently been made in our understanding of the gut microbiota. A large number of human intervention studies have been performed that have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota in line with the prebiotic concept. Thus the prebiotic effect is now a well-established scientific fact. The more data are accumulating, the more it will be recognised that such changes in the microbiota's composition, especially increase in bifidobacteria, can be regarded as a marker of intestinal health. The review is divided in chapters that cover the major areas of nutrition research where a prebiotic effect has tentatively been investigated for potential health benefits. The prebiotic effect has been shown to associate with modulation of biomarkers and activity(ies) of the immune system. Confirming the studies in adults, it has been demonstrated that, in infant nutrition, the prebiotic effect includes a significant change of gut microbiota composition, especially an increase of faecal concentrations of bifidobacteria. This concomitantly improves stool quality (pH, SCFA, frequency and consistency), reduces the risk of gastroenteritis and infections, improves general well-being and reduces the incidence of allergic symptoms such as atopic eczema. Changes in the gut microbiota composition are classically considered as one of the many factors involved in the pathogenesis of either inflammatory bowel disease or irritable bowel syndrome. The use of particular food products with a prebiotic effect has thus been tested in clinical trials with the objective to improve the clinical activity and well-being of patients with such disorders. Promising beneficial effects have been demonstrated in some preliminary studies, including changes in gut microbiota composition (especially increase in bifidobacteria concentration). Often associated with toxic load and/or miscellaneous risk factors, colon cancer is another pathology for which a possible role of gut microbiota composition has been hypothesised. Numerous experimental studies have reported reduction in incidence of tumours and cancers after feeding specific food products with a prebiotic effect. Some of these studies (including one human trial) have also reported that, in such conditions, gut microbiota composition was modified (especially due to increased concentration of bifidobacteria). Dietary intake of particular food products with a prebiotic effect has been shown, especially in adolescents, but also tentatively in postmenopausal women, to increase Ca absorption as well as bone Ca accretion and bone mineral density. Recent data, both from experimental models and from human studies, support the beneficial effects of particular food products with prebiotic properties on energy homaeostasis, satiety regulation and body weight gain. Together, with data in obese animals and patients, these studies support the hypothesis that gut microbiota composition (especially the number of bifidobacteria) may contribute to modulate metabolic processes associated with syndrome X, especially obesity and diabetes type 2. It is plausible, even though not exclusive, that these effects are linked to the microbiota-induced changes and it is feasible to conclude that their mechanisms fit into the prebiotic effect. However, the role of such changes in these health benefits remains to be definitively proven. As a result of the research activity that followed the publication of the prebiotic concept 15 years ago, it has become clear that products that cause a selective modification in the gut microbiota's composition and/or activity(ies) and thus strengthens normobiosis could either induce beneficial physiological effects in the colon and also in extra-intestinal compartments or contribute towards reducing the risk of dysbiosis and associated intestinal and systemic pathologies. © ILSI Europe 2010.
De Meester S.,Ghent University |
Callewaert C.,Ghent University |
De Mol E.,Syral |
Van Langenhove H.,Ghent University |
Dewulf J.,Ghent University
Biofuels, Bioproducts and Biorefining | Year: 2011
The multifunctionality of bioresources is a major opportunity for the future; it offers the ability to replace fossil-related market demands in a carbon neutral way. However, the switchover to a biobased economy faces two main challenges in comparison with the current fossil-based situation: biofeedstock requires an intensive cultivation step and furthermore there is a certain competition with the food chain which limits the amount of land available for new markets. So whilst biomass is seen as a 'renewable' resource, it is definitely not 'gratuite', inducing the need of an efficient cultivation and valorization. In this paper, a case study is executed to highlight that biorefining feedstock into a wide range of products is a thermodynamically efficient (81.1%) way of processing all molecules of the bioresources for specific purposes in different segments of the market demand. On the other hand, it is demonstrated in the second part of the paper that replacing fossils requires a certain amount of inputs from the Earth's crust causing additional thermodynamic losses in the production chain (15.3% efficient), which are quantified based on the resource footprint of the Cumulative Exergy Extracted from the Natural Environment (CEENE) methodology. A scenario assessment demonstrates the resulting tradeoff between the carbon footprint of bioproducts and the land, water, and minerals footprint; in the case study executed, 27% fossil resources are saved at the cost of 93% extra land, water and mineral input from the natural environment.© 2011 Society of Chemical Industry and John Wiley & Sons, Ltd.
Philippeau C.,AgroSup Dijon |
Respondek F.,Syral |
Julliand V.,AgroSup Dijon
Animal Feed Science and Technology | Year: 2010
Prebiotics, such as short-chain fructo-oligosaccharides (scFOS), have been shown to modify colonic microflora composition and activity in many humans and some animal species. However, little data are available on their fermentation characteristics by the ileal microbial community, and their effects on the small intestinal microflora composition. The aim of this study was to evaluate the in vitro fermentability of scFOS by ileal bacteria and the effect of scFOS on concentrations of the total anaerobic bacteria, Lactobacilli, Streptococci, Bifidobacteria and Clostridium perfringens in veal calf ileal contents. Two groups of 4 calves fed a finisher milk replacer and fibrous pellets were sacrificed 5 h after the morning meal. In each group, ileal contents were pooled and diluted with Lowe's medium. Two amounts of scFOS (100 and 250 mg) were tested in vitro versus a control (0 mg scFOS). Each bottle was incubated in duplicate for each treatment and each time point at 37°C in a shaking water bath. Bacterial concentrations were determined at 0, 3, 6, and 9 h and pH, gas production, volatile fatty acids (VFA), and lactate concentrations were measured every 1.5 h for 9 h. Over time, scFOS fermentation resulted in more gas production (P=0.055), higher total VFA concentrations (P<0.01), an increase in l-lactate concentration (P<0.01), as well as a lower pH value (P<0.01) than the control bottle. Acetate and butyrate concentrations increased (P<0.01) with scFOS fermentation. ScFOS fermentation enhanced growth of Lactobacilli (P=0.010), Streptococci (P=0.015) and lactic acid utilizing bacteria (P=0.025). C. perfringens concentration was not affected by scFOS addition. Based on our results, scFOS was fermented by bacteria of ileal contents in veal calves and its fermentation led to a selective stimulation of host bacteria. However, further studies are needed to determine impacts of scFOS on C. perfringens concentration in veal calf ileal contents. © 2010 Elsevier B.V.
Auger F.,Syral |
Auger F.,The Bakery |
Andre C.,French National Institute for Agricultural Research |
Andre C.,Heilongjiang University |
And 4 more authors.
Chemical Engineering and Technology | Year: 2015
The optimal control of processes dealing with non-Newtonian liquids requires the knowledge and control of the power demand of the mixing equipment. In this context, an extension of the Metzner and Otto concept to planetary mixers is proposed to adapt this concept to planetary mixers. The theoretical part of this work defines modified expressions of Reynolds and power numbers. These definitions introduce a characteristic velocity uch that is used to define the parameter Ks. A planetary mixer is employed to experimentally ascertain this guideline. Power consumption measurements carried out by mixing shear-thinning fluids permit to determine the Ks factor. This factor varies only slightly with the flow behavior index and may be regarded as a defined constant for this geometry. Finally, experiments with an additional shear-thickening fluid confirm the validity of this approach. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Auger F.,Syral |
Auger F.,The Bakery |
Delaplace G.,French National Institute for Agricultural Research |
Bouvier L.,French National Institute for Agricultural Research |
And 4 more authors.
Journal of Food Engineering | Year: 2013
The objective of this paper is to better characterize the influence of process parameters (impeller revolution speeds) on the performance of a planetary flour-beater mixer (mixer bowl P600 from Brabender) used in dough production. Firstly, we have theoretically described the path followed by the impeller tip into the vessel and the variation of the absolute velocity during its trajectory. This gives us indications during the transient mixing action of the material induced by this mixer. Secondly, we have theoretically and experimentally shown that for Newtonian fluids:The power dissipated by this mixer is strongly dependent on the impeller speed ratios.It is possible to obtain for this planetary mixer a unique master power curve, gathering on the same characteristic the influence of the dual impeller speeds on power consumption. This requires the introduction of a characteristic velocity, known as the maximal impeller tip velocity, into power and Reynolds numbers. The constant Kp of the mixer bowl P600, determined as the product of the modified Reynolds and power numbers, was found to be equal to 48.6. © 2013 Elsevier Ltd. All rights reserved.