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Dijon, France

Modugno C.,AgroSup | Paterson A.H.J.,Massey University | McLeod J.,Hilmar Cheese Company
Procedia Engineering

Industrially, after the crystallisation of lactose from mother liquor, the crystals are separated by centrifugation and then dried in a flash drier followed by a fluid bed drier. It is known that if the moisture content and/or particle size is not correct then lumping and caking of the lactose can occur in the flash drier causing operational problems.The aim of this study was to characterize the influence of water content and particle size distribution on the caking of lactose powders. Powders with different d50's and different water contents had their caking/clumping characteristics analyzed with a texture analyzer, a sticky plate and a blow tester to determine their cohesion. A theoretical approach looking at the capillary interactions of the liquid bridges between lactose crystals was taken from the literature to explain the results obtained. The results showed that lactose powder with a low d50 can cake easily as soon as the water content is higher than 3%. This cohesion between lactose crystals is due to liquid bridges linking them together. The number of bridges formed affects the level of cohesion: the more numerous they are, the more cohesive the lactose crystals are. Therefore, small particles cake more easily because the number of bridges in a given volume is higher than for bigger particles. It was predicted that the capillary force cannot hold together particles with d50 bigger than 400 μm and that was confirmed by experiment. Finally, in order to prevent the caking of lactose powders obtained by processes such as a decanter centrifuge, the lactose crystallization step should be controlled to obtain large crystal (with d50>300 μm) and/or the final water content should not be higher than 3%. © 2015 The Authors. Source

Minov S.V.,Belgium Institute for Agricultural and Fisheries Research | Cointault F.,AgroSup | Vangeyte J.,Belgium Institute for Agricultural and Fisheries Research | Pieters J.G.,Ghent University | Nuyttens D.,Belgium Institute for Agricultural and Fisheries Research
Transactions of the ASABE

Accurate spray and droplet characterization is important for increased understanding of the pesticide spray application process. The goal of this study was to develop two image acquisition systems based on single-droplet experiments using a piezoelectric single-droplet generator and a high-speed imaging technique, which will be used in a later stage of this study to evaluate micro and macro spray characteristics and droplet impact behavior. Experiments with different camera settings, lenses, diffusers, and light sources and the resulting image quality parameters showed the necessity of having a good image acquisition and processing system. The image analysis results contributed to selecting the optimal setup for measuring droplet size and velocity, which consisted of a high-speed camera with 6 ?s exposure time, a microscope lens at a working distance of 430 mm resulting in a field of view of 10.5 mm 8.4 mm, and a xenon backlight without a diffuser. The high-speed camera with a macro video zoom lens at a working distance of 143 mm with a larger field of view (88 mm 110 mm) in combination with a halogen spotlight with a diffuser was found to have the best potential for measuring macro spray characteristics, such as the droplet trajectory, spray angle, and spray shape. ©2015 American Society of Agricultural and Biological Engineers.. Source

Nadin M.,AgroSup | Rousseau D.,Ryerson University | Ghosh S.,University of Saskatchewan
LWT - Food Science and Technology

Fat crystal-stabilized water-in-oil emulsions were developed as a controlled release matrix for the delivery of salt. Glycerol monostearate (GMS), glycerol monooleate (GMO) and polyglycerol polyricinoleate (PGPR) were used as emulsifiers and hydrogenated canola oil (HCO) was added as a solid fat. Salt release towards an external aqueous phase was measured via conductivity as a function of temperature. Following 2h of release at room temperature, the GMS emulsion had the highest encapsulation efficiency followed by the PGPR-HCO, PGPR-only and GMO-HCO emulsions, respectively. The GMS crystals formed Pickering shells around the water droplets that effectively prevented salt transport whereas in the GMO-HCO emulsion, the presence of partial interfacial HCO crystal coverage resulted in lower retention. All crystal-stabilized emulsions showed rapid release of their salt load upon melting of the surrounding solid fat, while little temperature effect was observed with the PGPR-based emulsions. However, these emulsions were sensitive to the presence of a salt concentration gradient whereas the fat crystal-stabilized emulsions showed little response. Overall, this study demonstrated that the spatial distribution of the stabilizing fat crystals (i.e., interfacial vs. continuous phase) as well as the emulsifier type were critical factors controlling salt release patterns. © 2013 Elsevier Ltd. Source

Mession J.-L.,AgroSup | Assifaoui A.,AgroSup | Assifaoui A.,University of Burgundy | Lafarge C.,AgroSup | And 2 more authors.
Food Hydrocolloids

The physicochemical properties of a native, globular plant protein-linear anionic polysaccharide aqueous system at 20°C were investigated in conditions where biopolymers carry a net negative charge (pH 7.2, 0.1. M NaCl). The pea proteins-sodium alginate mixtures showed a phase separation mainly by thermodynamic incompatibility, characterized at both the macroscopic and microscopic scale. Phase diagram was established and confocal laser scanning microscopy (CLSM) provided accurate data on the microstructure morphology of the system, regarding its phase behavior. In admixture, sodium alginate induced a protein aggregation, certainly by a local depletion of the polysaccharide. Protein aggregates were present in both single-phase and biphasic mixtures, while increasing the sodium alginate concentration provided larger and denser protein microdomains, leading to a non-equilibrium state. By phase separation, the pea protein aggregates entrapped a part of the sodium alginate phase, thus modifying the protein volume fraction. Along a tie-line, a phase inversion phenomenon was detected, from a sodium alginate to a pea proteins-continuous phase. Rheological properties of the mixed systems depended on the biopolymer composition and were modified with respect to individual components. The protein-enriched phase volume fraction modified the flow behavior to non-Newtonian for starting concentrated mixtures; a shear-thinning at high shear rates was evidenced, while mixtures with a particularly high sodium alginate concentration (>0.8 wt%) had an apparent yield stress for low shear rates. Mechanical spectra showed that both protein enrichment within microdomains in the presence of alginate and stronger protein-protein interaction with time impacted the viscoelastic properties (G' and G' moduli) of the whole mixture. © 2011 Elsevier Ltd. Source

Assifaoui A.,AgroSup | Assifaoui A.,University of Burgundy | Chambin O.,AgroSup | Chambin O.,University of Burgundy | Cayot P.,University of Burgundy
Carbohydrate Polymers

The aim of this study was to investigate drug release from calcium and zinc pectinate beads and to understand the impact of medium electrolytes during drug transfer. A potential drug carrier for colonic drug delivery (rutin) was prepared with calcium and zinc pectinate beads and was tested in three different simulated intestinal fluids (pH 7.3) with phosphates (Sorensen's and Mc Ilvaine's buffers) and without phosphates (Tris-buffer). According to swelling studies and zinc ions release, it was showed that zinc ions keep adhering to the bead surface. Drug release and swelling behaviour from the two dosage forms depend not only on pH and ionic strength but also on the electrolytes there were in the dissolution medium. In calcium pectinate beads, rutin release was faster when phosphate buffers were used because precipitates (CaHPO4) were formed. This precipitate has a pumping effect on the calcium ions, destabilizing the gel structure and enhancing rutin release. In the case of zinc pectinate beads, two kinds of precipitate can be developed depending on the electrolytes composition. The development of Zn3(PO4)2 with a coating property reduced rutin release (Sorensen's buffer). On the other hand, development of ZnHPO4 has the pumping effect of zinc ions coming from the beads which increased rutin release (Mc Ilvaine's buffer). © 2011 Elsevier Ltd. All rights reserved. Source

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