References of "Toure, Yetioman"
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See detailConditioning materials with biomacromolecules: composition of the adlayer and influence on cleanability
Toure, Yetioman ULg; Genet, J. Michel; Dupont-Gillain, C. Christine et al

in Journal of Colloid and Interface Science (in press)

The influence of substrate hydrophobicity and biomacromolecules (dextran, bovine serum albumin - BSA) adsorption on the cleanability of surfaces soiled by spraying aqueous suspensions of quartz particles ... [more ▼]

The influence of substrate hydrophobicity and biomacromolecules (dextran, bovine serum albumin - BSA) adsorption on the cleanability of surfaces soiled by spraying aqueous suspensions of quartz particles (10 to 30 µm size), then dried, was investigated using glass and polystyrene as substrates. The cleanability was evaluated using radial flow cell (RFC). The surface composition was determined by X-ray photoelectron spectroscopy (XPS). The interpretation of XPS data allowed the complexity due to the ubiquitous presence of organic contaminants to be coped with, and the surface composition to be expressed in terms of both the amount of adlayer and the mass concentration of adlayer constituents. When soiled with a suspension of particles in water, glass was much less cleanable than polystyrene, which was attributed to its much lower water contact angle, in agreement with previous observations on starch soil. Dextran was easily desorbed and did not affect the cleanability. The presence of BSA at the interface strongly improved the cleanability of glass while the contact angle did not change appreciably. In contrast, soiling polystyrene with quartz particles suspended in a BSA solution instead of water did not change markedly the cleanability, while the contact angle was much lower and the aggregates of soiling particles were more flat. These observations are explained by the major role of capillary forces developed upon drying, which influence the closeness of the contact between the soiling particles and the substrate and, thereby, the adherence of particles. The capillary forces are proportional to the liquid surface tension and depend in a more complex way on contact angles of the particles and of the substrate. The dependence of cleanability on capillary forces, and in particular on the liquid surface tension, is predominant as compared with its dependence on the size and shape of the soiling aggregates, which influence the efficiency of shear forces exerted by the flowing water upon cleaning. [less ▲]

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See detailINFLUENCE OF WHEY PROTEIN DENATURATION ON ADHERENCE
Toure, Yetioman ULg; Rouxhet, G. Paul; Dupont-Gillain, C. Christine et al

Conference (2014, April)

This work reports on the influence of -lactoglobulin (β-LGB) and of its denaturation on the adherence of quartz particles, taken as a model of particulate soil, on stainless steel AISI 304 with mirror ... [more ▼]

This work reports on the influence of -lactoglobulin (β-LGB) and of its denaturation on the adherence of quartz particles, taken as a model of particulate soil, on stainless steel AISI 304 with mirror finish. The substrate was soiled with quartz suspensions in water or in β-LGB solutions as such or previously heated at 75°C, and dried at room temperature or in an oven at 75°C. Cleanability was evaluated after exposure to water in a radial flow chamber. Auxiliary characterizations were the surface tension and protein concentration of the solution, surface analysis of the substrate by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The contact of stainless steel with -LGB led to adsorption of the protein, which dominated the composition of the organic layer with respect to contaminants initially present, and was not markedly desorbed upon rinsing. The presence of β-LGB at the quartz particle/substrate interface slightly increased the adherence, which was further increased when the protein was denatured. On the other hand, denaturation of -LGB enhanced its surfactant effect at the water/air interface. Comparison with systems investigated before suggests that the influence of protein via droplet spreading and soiling particles aggregation may be of minor importance compared to direct effects on the substrate/quartz interface. Stainless steel does not behave as a hydrophilic substrate owing to its surface contamination with organic compounds. It appears suitable to examine the influence of the initial surface state of stainless steel on its behavior regarding soiling and cleaning. [less ▲]

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See detailINFLUENCE OF WHEY PROTEIN DENATURATION ON ADHERENCE
Toure, Yetioman ULg; Rouxhet, G. Paul; Dupont-Gillain, C. Christine et al

in Dr Wilson, I.; Chew, Y.M.J. (Eds.) Fouling and Cleaning in Food Processing (2014, April)

This work reports on the influence of -lactoglobulin (β-LGB) and of its denaturation on the adherence of quartz particles, taken as a model of particulate soil, on stainless steel AISI 304 with mirror ... [more ▼]

This work reports on the influence of -lactoglobulin (β-LGB) and of its denaturation on the adherence of quartz particles, taken as a model of particulate soil, on stainless steel AISI 304 with mirror finish. The substrate was soiled with quartz suspensions in water or in β-LGB solutions as such or previously heated at 75°C, and dried at room temperature or in an oven at 75°C. Cleanability was evaluated after exposure to water in a radial flow chamber. Auxiliary characterizations were the surface tension and protein concentration of the solution, surface analysis of the substrate by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The contact of stainless steel with -LGB led to adsorption of the protein, which dominated the composition of the organic layer with respect to contaminants initially present, and was not markedly desorbed upon rinsing. The presence of β-LGB at the quartz particle/substrate interface slightly increased the adherence, which was further increased when the protein was denatured. On the other hand, denaturation of -LGB enhanced its surfactant effect at the water/air interface. Comparison with systems investigated before suggests that the influence of protein via droplet spreading and soiling particles aggregation may be of minor importance compared to direct effects on the substrate/quartz interface. Stainless steel does not behave as a hydrophilic substrate owing to its surface contamination with organic compounds. It appears suitable to examine the influence of the initial surface state of stainless steel on its behavior regarding soiling and cleaning. [less ▲]

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See detailINFLUENCE OF SOLUBLE PROTEINS ON THE ADHERENCE OF PARTICULATE SOILS
Toure, Yetioman ULg; Rouxhet, Paul; Dupont-Gillain, Christine et al

in Malayeri, Reza; Watkinson, Paul A.; Müller-Steinhagen, Hans (Eds.) Proceedings of International Conference on Heat Exchanger Fouling and Cleaning - 2013 (Peer-reviewed) (2013, December)

Adsorbed compounds from food and pharmaceutical mixtures may influence interactions at interfaces and thus fouling and cleaning. In this study, quartz particles (10 to 30µm) were used as a model soil for ... [more ▼]

Adsorbed compounds from food and pharmaceutical mixtures may influence interactions at interfaces and thus fouling and cleaning. In this study, quartz particles (10 to 30µm) were used as a model soil for examining the effect of dissolved proteins on the cleanability of substrates after soiling and drying. Glass and stainless steel pretreated by UV-Ozone (StSteel-UVO) were used as model hydrophilic substrates, while hydrophobic substrates were represented by stainless steel cleaned with ethanol (StSteel-Eth) and polystyrene. BSA and β-LGB were used as proteins. The quartz suspensions used for soiling were prepared in pure water and in a solution of each protein. After soiling and drying, the cleanability was evaluated using a radial-flow cell, with pure water as the cleaning fluid. The presence of proteins in the suspension used for soiling hydrophilic substrates (Glass and StSteel-UVO), decreased the adherence of quartz particles. Its effect was less marked and tended to be opposite for less hydrophilic substrates (StSteel-Eth, Polystyrene). The adherence cannot be explained by a simple relation with the contact angle. Other factors may be the solution surface tension itself and the protein behavior at the interfaces created by drying and by rehydratation during cleaning. When considering the influence of substrate on soiling, it must be kept in mind that high surface energy solids (metals, oxides) are readily contaminated in contact with air and lose their hydrophilicity. This may improve the substrate behavior regarding cleanability with respect to particulate soil. [less ▲]

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See detailSoil model systems used to assess fouling, soil adherence and surface cleanability in the laboratory: a review
Toure, Yetioman ULg; Mabon, Nicolas; Sindic, Marianne ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(3), 527-539

Surface fouling is a chronic problem in processing industries. The hygienic state of surfaces is thus a critical parameter with respect to the performance of the production process and to the final ... [more ▼]

Surface fouling is a chronic problem in processing industries. The hygienic state of surfaces is thus a critical parameter with respect to the performance of the production process and to the final quality of the product. For this reason, cleaning and disinfection are essential. The most important first step in implementing a fouling mitigation strategy through cleaning and disinfection is to understand the mechanisms of fouling. This allows ways to be found to reduce, even to eliminate fouling, or to improve the effectiveness of cleaning and disinfection. This paper reviews the relevant literature and summarizes a selection of soil model systems used to aid such improvements. Organic, mineral, microbial, particulate, and composite soil model systems are presented. These soil model systems are of particular relevance in the study of fouling, cleaning or soil adhesion onto solid surfaces in the laboratory environment. The key features of the models, as well as their practical advantages and disadvantages, are described and discussed. [less ▲]

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See detailINFLUENCE OF DISSOLVED MACROMOLECULES ON ADHERENCE OF PARTICULATE SOILS
Toure, Yetioman ULg; Sindic, Marianne ULg; Rouxhet, G. Paul

Conference (2013, June 12)

Polysaccharides, proteins, lipids and other biopolymers are the main components of food and pharmaceutical mixtures and may influence interactions at interfaces and thus fouling and cleaning. In this ... [more ▼]

Polysaccharides, proteins, lipids and other biopolymers are the main components of food and pharmaceutical mixtures and may influence interactions at interfaces and thus fouling and cleaning. In this study, quartz particles (10 to 30µm) were used as a model soil for examining the effect of dissolved proteins on the cleanability of substrates after soiling and drying. Glass and stainless steel pretreated by UV-Ozone (StSteel-UVO) were used as model hydrophilic substrates, while hydrophobic substrates were represented by stainless steel cleaned with ethanol (StSteel-Eth) and polystyrene. BSA and β-LGB were used as proteins. The quartz suspensions used for soiling (150g/L) were prepared in pure water and in a solution of each protein (8g/l). After soiling and drying, the cleanability was evaluated using a radial-flow cell, with pure water as the cleaning fluid. When soiling was made with a quartz suspension in pure water, the soil adherence increased with substrate hydrophilicity. This may be explained by better droplet spreading and increase of the capillary forces created upon drying. The presence of proteins in the suspension used for soiling hydrophilic substrates (Glass and StSteel-UVO), decreased the adherence of quartz particles. Its effect was less marked and tended to be opposite for less hydrophilic substrates (StSteel-Eth, Polystyrene). The comparison of different substrates and two proteins showed that the adherence cannot be explained by a simple relation with the contact angle. Other factors may be the solution surface tension itself and the protein behavior at the interfaces created by drying and by rehydratation during cleaning. When considering the influence of substrate on soiling, it must be kept in mind that high surface energy solids (metals, oxides) are readily contaminated in contact with air and lose their hydrophilicity. Amazingly this may improve the substrate behavior regarding cleanability with respect to particulate soil. [less ▲]

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See detailDEVELOPMENT OF FROZEN-FRIED YAM SLICES: OPTIMIZATION OF THE PROCESSING CONDITIONS
Toure, Yetioman ULg; Nindjin, Charlemagne; Brostaux, Yves ULg et al

in African Journal of Food, Agriculture, Nutrition and Development (2012), 12(7), 7055-7071

The research performed on yam processing mainly concerns the production of crisps and flour. However, its transformation into deep-frozen French fries does not necessitate any other equipment than those ... [more ▼]

The research performed on yam processing mainly concerns the production of crisps and flour. However, its transformation into deep-frozen French fries does not necessitate any other equipment than those used for potatoes. The industrial process of production of frozen French fries traditionally includes a pre-frying step. These steps contribute to the development of color and crispness, and the oil partially absorbed inhibits dehydration during the freezing step. The aim of this study was to optimize frying conditions of deep-frozen fried yam (Dioscorea cayenensis var Kponan) slices. The effect of pre-frying time and temperature, final frying time and temperature on the oil uptake, texture, dry matter and colour of the fried yam slices has been studied. Frying conditions optimized with Box-Behnken experimental design were short pre-frying and frying conditions at high temperature characterized by pre-frying temperature at 157-170°C during 5-9s and frying temperature at 181-188°C for 2min 15s-2min 30s; or long pre-frying and frying conditions at low temperature characterized by pre-frying temperature at 150-158°C during 10-15s and frying temperature 170-177°C for 3-3min 15s. An adiabatic system was also developed by means of an insulator in which the core temperature of fried yam slices can be maintained constant at about 55°C after 15min of cooling, facilitating texture measurements at constant temperature. The present results may help in choosing the yam slices frying condition to be applied in order to achieve the desirable fried yam slices quality, required for protection against certain diseases like obesity. These models may also provide guidance as to how to control these quality parameters by altering four key environmental factors, pre-frying temperature and time and, final frying temperature and time. This process can also be commercialized and does not necessitate any other cost for equipment than those used for potatoes French fries and might be an interesting way of added value processing for this highly perishable yam tuber. [less ▲]

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See detailINFLUENCE OF SOLUBLE POLYSACCHARIDE ON THE ADHERENCE OF PARTICULATE SOILS
Toure, Yetioman ULg; Rouxhet, Paul G.; Dupont-Gillain, C. Christine et al

in Malayeri, Reza; Watkinson, Paul A.; Müller-Steinhagen, Hans (Eds.) Proceedings of International Conference on Heat Exchanger Fouling and Cleaning - 2011 (Peer-reviewed) (2011, June 11)

The removal of particulate soils from solid surfaces is the key process of cleaning many industrial devices, such as heat exchangers and spray dryers (food and pharmaceutical sector), and may be ... [more ▼]

The removal of particulate soils from solid surfaces is the key process of cleaning many industrial devices, such as heat exchangers and spray dryers (food and pharmaceutical sector), and may be influenced by the presence of solutes, in particular of macromolecules. The present study deals with the influence of soluble polysaccharide on the adherence of particulate fouling of open surfaces and on subsequent cleaning. Model substrates differing by hydrophobicity (glass and polystyrene) were soiled with a suspension of quartz particles, taken as a model of hard hydrophilic soil. Dextran was chosen as a model of soluble polysaccharide. The substrates were soiled with or without previous conditioning with the polysaccharide solution (80mg/l). The quartz particles suspension was prepared in three ways: (i) suspension in a polysaccharide solution (80mg/l), (ii) same as (i) and subsequent washing three times, (iii) suspension in water. The substrates were soiled by spraying the suspension and dried for 30min before cleaning treatment with a water flow in a radial flow chamber. The aggregates observed after soiling differed considerably between glass and polystyrene, whether the substrate and/or the quartz particles were or were not conditioned with dextran. Conditioning polystyrene with dextran increased slightly the adherence of quartz particles, while the opposite was observed when conditioning glass with dextran, whatever the mode of quartz particles conditioning. The effect of conditioning quartz particles with dextran at the concentration used was not significant. [less ▲]

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See detailINFLUENCE OF SOLUBLE POLYSACCHARIDE ON THE ADHERENCE OF PARTICULATE SOILS
Toure, Yetioman ULg; Rouxhet, G. Paul; Dupont-Gillain, C. Christine et al

Conference (2011, June)

The removal of particulate soils from solid surfaces is the key process of cleaning many industrial devices, such as heat exchangers and spray dryers (food and pharmaceutical sector), and may be ... [more ▼]

The removal of particulate soils from solid surfaces is the key process of cleaning many industrial devices, such as heat exchangers and spray dryers (food and pharmaceutical sector), and may be influenced by the presence of solutes, in particular of macromolecules. The present study deals with the influence of soluble polysaccharide on the adherence of particulate fouling of open surfaces and on subsequent cleaning. Model surfaces differing by hydrophobicity (glass and polystyrene) were soiled with a suspension of quartz particles, taken as a model of hard hydrophilic soil. Dextran was chosen as a model of soluble polysaccharide. The surfaces were soiled with or without previous conditioning with the polysaccharide solution (80mg/l). The quartz particles suspension was prepared in three ways: (i) suspension in a polysaccharide solution (80mg/l), (ii) same as (i) and subsequent washing three times, (iii) suspension in water. The surfaces were soiled by spraying the suspension and dried for 30min before cleaning treatment with a water flow in a radial flow chamber. The aggregates observed after soiling differed considerably between glass and polystyrene, whether the surface and/or the quartz particles are conditioned with dextran. Conditioning polystyrene with dextran increased slightly the adherence of quartz particles, while the opposite was observed when conditioning glass with dextran, whatever the mode of quartz particles conditioning. The effect of conditioning quartz particles with dextran at the concentration used was not significant. [less ▲]

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