Oligosaccharides in goat milk: structure, health effects and isolation
Kiskini, A. ; Difilippo, E. - \ 2013
Cellular and Molecular Biology 59 (2013)1. - ISSN 0145-5680 - p. 25 - 30.
lactose-derived oligosaccharides - field h-1-nmr spectroscopy - ceramic membranes - fucosylated oligosaccharides - bifidobacterium-bifidum - deicher antibodies - induced colitis - caprine milk - bovine-milk - colostrum
Oligosaccharides have been widely recognized for their prebiotic and anti-infective properties. Among the different types of mammalian milk, the one of humans is the richest source of naturally derived oligosaccharides. However, their use as a basis for functional foods is hampered, due to their structural complexity, which in turn makes their re-synthesis extremely difficult. Thus, oligosaccharides from other sources have to be used. In this sense, goat milk constitutes a very appealing candidate, as it contains the highest amount of oligosaccharides among domestic animals, while goat milk oligosaccharides show significant similarities to human milk oligosaccharides from a structural point of view. Studies on goat milk oligosaccharides are scant, and more data is required in order to provide solid clinical evidence of their beneficial effects on humans. The aim of this review is to collect and present the main research findings on goat milk oligosaccharides structure, health effects and isolation.
Review of hypotheses for fouling during beer clarification using membranes
Mepschen, A. ; Sman, R.G.M. van der; Vollebregt, H.M. ; Noordman, T.R. - \ 2012
Journal of Membrane Science 396 (2012). - ISSN 0376-7388 - p. 22 - 31.
cross-flow microfiltration - governing permeate flux - pressure-driven flow - beta-glucans - transmembrane pressure - colloidal suspensions - ceramic membranes - protein rejection - self-diffusion - model
Hypotheses concerning the fouling of membranes during beer clarification via crossflow microfiltration are reviewed. Beer has been classified into three groups of components, each having a different kind of fouling mechanisms – but also having interactions with other modes of fouling. The membrane fouling also strongly depends on the characteristics of the membrane. An optimal pore diameter and membrane morphology can be identified. The various hypotheses have been formulated in terms of mathematical models, which are tested using experimental data of dead-end filtration of beer. This comparison shows that our hypotheses are quite likely to be valid, and form a good basis for further model-based exploration of the optimization of the beer clarification process. Due to the similarity of beer with biotechnological broths, the presented fouling hypotheses extend beyond the original application of beer microfiltration.
Droplet formation in a T-shaped microchannel junction: A model system for membrane emulsification
Graaf, S. van der; Steegmans, M.L.J. ; Sman, R.G.M. van der; Schroën, C.G.P.H. ; Boom, R.M. - \ 2005
Colloids and Surfaces. A: Physicochemical and Engineering Aspects 266 (2005)1-3. - ISSN 0927-7757 - p. 106 - 116.
dynamic interfacial-tension - ceramic membranes - emulsions - simulation
Droplet formation was studied in a glass microchip with a small channel containing to-be-dispersed phase perpendicular to a large channel with a cross-flowing continuous phase. This resembles the situation during cross-flow membrane emulsification. In this model system, droplets are formed at a T-junction of these two rectangular channels; the droplet formation and detachment process is studied from aside with a microscope connected to a high speed camera. Monodisperse hexadecane droplets were formed in aqueous solutions with various concentrations of ethanol, sodium dodecyl sulfate (SDS) and Tween 20. Just before detachment, the neck diameter was measured and a critical neck diameter of 4 ¿m was found, which is in the same range as the depth of the channel (5 ¿m). After detachment, the droplet diameter was determined for the various aqueous solutions. The droplet diameter increased as a function of the oil flow rate. Use of surfactants (SDS, Tween 20) resulted in the formation of smaller droplets than in systems without surfactants. A simple model is proposed to describe the droplet formation process, inspired on the idea that the necking process is a dynamic process that takes a certain time, which explains the influence of both the oil flow rate and the properties of the fluid phases on the final droplet size. Fitting the experimental data with the model results in a necking time of about 11 ms.
Status of cross-flow membrane emulsification and outlook for industrial application
Gijsbertsen-Abrahamse, A.J. ; Padt, A. van der; Boom, R.M. - \ 2004
Journal of Membrane Science 230 (2004)1-2. - ISSN 0376-7388 - p. 149 - 159.
shirasu-porous-glass - in-water emulsions - microchannel emulsification - droplet formation - ceramic membranes - microspheres - size - pore
Cross-flow membrane emulsification has great potential to produce monodisperse emulsions and emulsions with shear sensitive components. However, until now, only low disperse phase fluxes were obtained. A low flux maybe a limiting factor for emulsion production on a commercial scale. Therefore, the effects of membrane parameters on the disperse phase flux are estimated. Besides, the effects of these parameters on the droplet size and droplet size distribution are qualitatively described. Wetting properties, pore size and porosity mainly determine the droplet size (distribution). Membrane morphology largely determines the disperse phase flux. As an example, industrial-scale production of culinary cream was chosen to evaluate the required membrane area of different types of membranes: an SPG membrane, an alpha-Al2O3 membrane and a microsieve. Due to the totally different morphologies of these membranes, the fraction of active pores is I for a microsieve and is very low for the other membranes. The choice of the optimal membrane did not depend on the production strategy: either to produce large quantities or to produce monodisperse emulsions, the best suitable was a microsieve with an area requirement of around I m(2). In general, the total membrane resistance should be low to obtain a large disperse phase flux. In contrast, the membrane resistance should be high to obtain monodisperse emulsions when using membranes with a high porosity. (C) 2003 Elsevier B.V. All rights reserved.