TECLIS PUBLICATIONS: Foam analyzer > Foamscan
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Fields: 食品工业 - 蛋白质 - 乳液 - 其他研究 -
食品工业
| Magazine |
Langmuir 2005, 21, 7786-7795 |
| Year |
2005 |
| Autors |
Christophe Schmitta, Tânia Palma da Silvaaa, Claudine Bovaya, Sabrina Rami-Shojaeib, Philippe Frossarda, Eric Kolodziejczyka, Martin E. Lesera |
| Estb. |
a aDepartment of Food Science, Nestlé Research Center, Vers-chez-les-Blanc, CH-1000 Lausanne 26, Switzerland
b bDepartment of Bioanalytical Science, Nestlé Research Center, Vers-chez-les-Blanc, CH-1000 Lausanne 26, Switzerland |
| Abstract |
The electrostatic complexation between â-lactoglobulin and acacia gum was investigated at pH 4.2 and 25 °C. The binding isotherm revealed a spontaneous exothermic reaction, leading to a ΔHobs = -2108 kJ mol-1 and a saturation protein to polysaccharide weight mixing ratio of 2:1. Soluble electrostatic complexes formed in these conditions were characterized by a hydrodynamic diameter of 119 ±0.6 nm and a polydispersity index of 0.097. The effect of time on the interfacial and foaming properties of these soluble complexes was investigated at a concentration of 0.1 wt % at two different times after mixing (4 min, referred as t ~0 h and t=24 h). At t~0 h, the mixture is mainly made of aggregating soluble electrostatic complexes, whereas after 24 h these complexes have already insolubilize to form liquid coacervates. The surface elasticity, viscosity and phase angle obtained at low frequency (0.01 Hz) using oscillating bubble tensiometry revealed higher fluidity and less rigidity in the film formed at t ~0 h. This observation was confirmed by diminishing bubble experiments coupled with microscopy of the thin film. It was thicker, more homogeneous and contained more water at t ~ 0 h as compared to t =24 h (thinner film, less water). This led to very different gas permeability’s of Kt~0h=0.021cms-1 and Kt=24h=0.449cms-1, respectively. Aqueous foams produced with the β-lactoglobulin/acacia gum electrostatic complexes or coacervates exhibited very different stability. The former (t ~0 h) had a stable volume, combining low drainage rate and mainly air bubble disproportionation as the destabilization mechanism. By contrast, using coacervates aged for 24 h, the foam was significantly less stable, combining fast liquid drainage and air bubble destabilization though fast gas diffusion followed by film rupture and bubble coalescence. The strong effect of time on the air/water interfacial properties of the β–lactoglobulin/acacia gum electrostatic complexes can be understood by their reorganization at the interface to form a coacervate phase that is more fluid/viscous at t ~0 h vs rigid/elastic at t=24 h. |
| Magazine |
Food Hydrocolloids 19 (2005) 1005–1015 |
| Year |
2005 |
| Autors |
R.J. Redgwell, C. Schmitt, M. Beaulieu, D. Curti |
| Estb. |
Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, P.O. Box 44, CH-1000, Lausanne 26, Switzerland |
| Abstract |
The arabinogalactan–protein (AGP) fraction of green coffee beans accounts for ~15% of the dry bean. A procedure was developed to solubilise most of the AGP content of the beans so that its properties as a hydrocolloid could be investigated. An AGP fraction was partially purified from green arabica coffee beans, its rheological properties characterised and compared to those of some commercially important hydrocolloids, particularly acacia gum. The coffee AGP fraction dissolved readily in water to give colourless clear solutions. The polymer was a polyelectrolyte with a high molecular weight (Mw 3.78*106), characterised by a narrow polydispersity index (Mw/Mn 1.3). The intrinsic viscosity was close to that of acacia gum ([η]Z0.23 dL-1), but a 1 wt% solution of coffee AGP was three times more viscous than acacia gum at the same concentration. Coffee AGP showed Newtonian flow for concentrations below 6 wt%, but above this concentration the flow behaviour entered a shear-thinning regime. The coffee AGP fraction possessed interesting foaming properties providing that the biopolymer concentration was high enough to initially stabilize the interface that is created. The high molecular weight of coffee AGP combined with its globular structure conferred upon it a high ability to retain water within a foam thin film. However, the structure of the interfacial film was less effective than that of acacia gum to entrap efficiently the gas into the foam. In summary, coffee AGP shows some interesting rheological features which suggest that coffee beans could be used as an alternative source of the class of surface-active polymers which find many commercial applications. |
| Magazine |
Advances in Colloid and Interface Science 140 (2008) 95–113 |
| Year |
2008 |
| Autors |
Juan M. Rodríguez Patino, Cecilio Carrera Sánchez, Ma. Rosario Rodríguez Nino |
| Estb. |
Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, C/ Prof. García González, 1, E-41012-Sevilla, Spain |
| Abstract |
The manufacture of food dispersions (emulsions and foams) with specific quality attributes depends on the selection of the most appropriate raw materials and processing conditions. These dispersions being thermodynamically unstable require the use of emulsifiers (proteins, lipids, phospholipids, surfactants etc.). Emulsifiers typically coexist in the interfacial layer with specific functions in the processing and properties of the final product. The optimum use of emulsifiers depends on our knowledge of their interfacial physico-chemical characteristics — such as surface activity, amount adsorbed, structure, thickness, topography, ability to desorb (stability), lateral mobility, interactions between adsorbed molecules, ability to change conformation, interfacial rheological properties, etc. —, the kinetics of film formation and other associated physico-chemical properties at fluid interfaces. These monolayers constitute well defined systems for the analysis of food colloids at the micro- and nano-scale level, with several advantages for fundamental studies. In the present review we are concerned with the analysis of physico-chemical properties of emulsifier films at fluid interfaces in relation to foaming. Information about the above properties would be very helpful in the prediction of optimised formulations for food foams. We concluded that at surface pressures lower than that of monolayer saturation the foaming capacity is low, or even zero. A close relationship was observed between foaming capacity and the rate of diffusion of the foaming agent to the air–water interface. However, the foam stability correlates with the properties of the film at long-term adsorption. |
| Magazine |
Food Hydrocolloids 21 (2007) 782–793 |
| Year |
2007 |
| Autors |
Juan M. Rodriguez Patinoa,José Minones Condea,Herminia Millan Linaresa,Justo J. Pedroche Jiménezb,Cecilio Carrera Sancheza, Francisco Millan Rodriguezb |
| Estb. |
a Departamento de Ingenieria Quimica, Facultad de Quimica, Universidad de Sevilla, C/. Prof. Garcia Gonza´lez 1, 41012-Seville, Spain
b Departamento de Fisiologia y Tecnologıia de Productos Vegetales, Instituto de la Grasa C.S.I.C. Avda, Padre Garcia Tejero, 4, 41012-Sevilla, Spain |
| Abstract |
Plant proteins are increasingly being used as an alternative to proteins from animal sources in human nutrition. In this contribution we are concerned with the analysis of interfacial (adsorption isotherm, rate of adsorption, and surface dilatational properties) and foaming characteristics (foaming power and foam stability) of a sunflower protein isolate (SPI) and its hydrolysates with different degrees of hydrolysis (DH), as a function of the protein concentration in aqueous solution. Caseinate has been utilized as a protein of reference. We have observed that the adsorption and foaming power (foam capacity, gas and liquid retention in the foam, and foam density) increases with the protein concentration in the aqueous phase, depending on the DH. The adsorption kinetic at short adsorption time is diffusion controlled. However, the controlling mechanism at long-term adsorption is the penetration of the protein at the interface. A close relationship was observed between foaming and the rate of diffusion of the protein to the air–water interface. The foam stability — quantified by the relaxation time due to drainage (td) and disproportionation /coalescence (tdc)—correlates with the equilibrium surface pressure (πe) of the film adsorbed from aqueous solutions of the protein. |
| Magazine |
J. Agric. Food Chem. 2005, 53, 9089-9099 |
| Year |
2005 |
| Autors |
Christophe Schmitt, Claudine Bovay and Philippe Frossard |
| Estb. |
Nestlé Research Center, Department of Food Science, Vers-chez-les-Blanc, CH-1000 Lausanne 26, Switzerland |
| Abstract |
The formation of conjugates between β-lactoglobulin and acacia gum based on electrostatic complexes formed at pH 4.2 was investigated upon dry-state incubation for up to 14 days at 60 °C and 79% relative humidity (RH). By means of SEC-HPLC and RP-HPLC, it was shown that the β-lactoglobulin incubated alone was able to form polymers with molecular masses higher than 200 kDa until 50% of the initial monomeric protein disappeared after 14 days. In the presence of acacia gum at initial protein to polysaccharide weight mixing ratios of 2:1 and 1:2, only 35% of the initial β-lactoglobulin monomers disappeared after 14 days. Using RP-HPLC, an apparent reaction order of 2 was found for the disappearance of monomeric β-lactoglobulin both in the presence or absence of acacia gum. However, the reaction rate was faster in the absence of acacia gum. SDS-PAGE electrophoresis with silver staining confirmed the formation of β-lactoglobulin/acacia gum conjugates. The solubility curves of the incubated β-lactoglobulin showed a minimum around pH 4-5. By contrast, the minimum of solubility of the β-lactoglobulin/acacia gum incubated mixtures shifted to lower pH values compared to initial mixtures. The conjugates exhibited higher foam capacity than the incubated protein as well as lower equilibrium air/water surface tension. Conjugation at ratio 1:2 led to increased interfacial viscosity (300 mN s m-1 at 0.01 Hz) compared to β-lactoglobulin alone (100 mN s m-1 at 0.01 Hz), but similar interfacial elasticity (30-40 mN m-1). The foam capacity of the conjugates was significantly higher than that of the incubated β-lactoglobulin as well as foam expansion and drainage time, especially at pH 5.3, i.e., higher than the pH of formation of the conjugates. |
| Magazine |
Food Biophysics (2007) 2:76–82 |
| Year |
2007 |
| Autors |
Imène Ben Thabeta, Hamadi Attiaa,Souhail Besbesa,Claude Deroanneb,Frédéric Francisc,Nour-Eddine Drirad,Christophe Bleckerbb |
| Estb. |
aDépartement de Biologie, Unité Analyses Alimentaires, Ecole, Nationale d’Ingénieurs de Sfax, route de Soukra B.P. W., 3038 Sfax, Tunisia
bUnité de Technologie des Industries Agro-alimentaires, Faculté, Universitaire des Sciences Agronomiques de Gembloux, passage des Déportés 2,5030 Gembloux, Belgium
cLaboratoire de Biotechnologie Végétale,Faculté des Sciences de Sfax,route de Soukra,3038 Sfax, Tunisia
d Unité d’Entomologie Fonctionnelle et Evolutive, Faculté, Universitaire des Sciences Agronomiques de Gembloux, passage des Déportés 2,5030 Gembloux, Belgium |
| Abstract |
The present work aimed to study the physicochemical characteristics and the functional properties of the male date palm sap (Phoenix dactylifera L.). The surface properties at the air–water interface were studied on the basis of the drop volume method. Foaming properties (foam capacity and stability) were evaluated using bubbling method by optical and conductimetric measurements (foamscan). Composition analysis revealed a high sugar content (92.29% w/w dry matter basis) with dominance of sucrose. Sap contains also 5.14% w/w of proteins and 2.57% w/w of ash. Proteins are probably the source of the surface activity and the observed foam power. At higher contents of dry matter, lyophilized sap solutions showed Newtonian comportment and improved surface activity and foam properties. Results present some interesting functional properties that suggest to deepen research particularly in sap proteins. |
| Magazine |
Langmuir 2007, 23, 4155-4166 |
| Year |
2007 |
| Autors |
Christophe Schmitt, Claudine Bovay, Martine Rouvet, Sabrina Shojaei-Rami and Eric Kolodziejczyk |
| Estb. |
Department of Food Science and Department of Bioanalytical Science, Nestle´ Research Center, Vers-chez-les-Blanc, CH-1000 Lausanne 26, Switzerland |
| Abstract |
Whey protein isolate was heat-treated at 85 °C for 15 min at pH ranging from 6.0 to 7.0 in the presence of NaCl in order to generate the highest possible amount of soluble aggregates before insolubility occurred. These whey protein soluble aggregates were characterized for composition, hydrodynamic diameter, apparent molecular weight, -potential, surface hydrophobicity index, activated thiol group content, and microstructure. The adsorption kinetics and rheological properties (E’, ηd) of these soluble aggregates were probed at the air/water interface. In addition, the gas permeability of a single bubble stabilized by the whey protein soluble aggregates was determined. Finally, the foaming and foamstabilizing properties of these aggregates were measured. The amount of whey protein soluble aggregates after heat treatment was increased from 75% to 95% from pH 6.0 to pH 7.0 by addition of 5 mMto 120 mM NaCl, respectively. These soluble aggregates involved major whey protein fractions and exhibited a maximum of activated thiol group content at pH>6.6. The hydrodynamic radius and the surface hydrophobicity index of the soluble aggregates increased from pH 6.0 to 7.0, but the molecular weight and ú-potential decreased. This loss of apparent density was clearly confirmed by microscopy as the soluble aggregates shifted from a spherical/compact structure at pH 6.0 to a more fibrillar/elongated structure at pH 7.0. Surface adsorption was faster for soluble aggregates formed at pH 6.8 and 7.0 in the presence of 100 and 120 mM NaCl, respectively. However, interfacial elasticity and viscosity measured at 0.01 Hz were similar from pH 6.0 to 7.0. Single bubble gas permeability significantly decreased for aggregates generated at pH > 6.6. Furthermore, these aggregates exhibited the highest foamability and foam liquid stability. Air bubble size within the foam was the lowest at pH 7.0. The coarsening exponent, R, fell within predicted values of 1/3 and 1/2, except for very dry foams where it was 1/5. |
蛋白质
| Magazine |
Image and Vision Computing 27 (2009) 609–622 |
| Year |
2009 |
| Autors |
Sabrina Rami-shojaeia, Corinne Vachierb and Christophe Schmitta |
| Estb. |
a Nestlé Research Center, PO Box 44, Vers-chez-les-Blanc, 1000 Lausanne, Suisse
b Centre de Mathématiques et Leurs Applications, ENS Cachan, CNRS, PRES UniverSud, 61, Av. du Pt Wilson, F-94235 Cachan cedex, France |
| Abstract |
Aqueous foams occur in several industrial applications including food production. One of the challenging issues in foams study is to evaluate the air bubbles stability. This problem is addressed in the present work using sequences of 2D macroscopic images of aqueous foams carried out in a glass column.
Despite commercial softwares that are currently used in microscopy, the automatic analysis of foam sequences is still an unsolved problem. It can be related to two fundamental problems in the field of image analysis: the granulometric analysis and the automatic tracking of objects in image sequences. Rather than an adaptation of existing granulometric or tracking methods, the proposed foam analyzer consists in a new algorithm based on a double tracking of the foam bubbles: a scale-space tracking, where the scale parameter is the size, and a temporal tracking. It ensures a complete description of any bubble through the time and the detection of any bubbles interaction so that the foam’s structure is finally entirely and very precisely described.
The proposed foam analyzer has been validated by comparing the characteristics computed by the automatic method to those that can be predicted via the foams physical properties. |
| Magazine |
Image and Vision Computing 27 (2009) 609–622 |
| Year |
2009 |
| Autors |
Bénédicte Rulliera, Monique A.V. Axelosa, Dominique Langevinb, Bruno Novalesa |
| Estb. |
aInstitut National de la Recherche Agronomique, UR1268 Biopolymères, Interactions, Assemblages, INRA, Equipe Interfaces Systèmes Dispersés, Rue de la Géraudière, 44316 Nantes Cedex 03, France
bLaboratoire de Physique des Solides, Université Paris-Sud, Bâtiment 510, 91405 Orsay, France |
| Abstract |
Single foam films made from aqueous protein solutions containing aggregates have been studied using a thin film balance apparatus. When the solutions are free from non-aggregated proteins, the films are either fluid or gelified, depending on the aggregate size. When non-aggregated proteins are present, they adsorb at the film surfaces, acting as anchors for the aggregates, and ultimately leading to stable foam films if the amount of non-aggregated proteins is sufficient. In all cases, gel-like films are more stable than fluid films and there is a good correlation between foam and film stability. |
| Magazine |
Journal of Colloid and Interface Science |
| Year |
2009 |
| Autors |
Bénédicte Rulliera, Monique A.V. Axelosa, Dominique Langevinb, Bruno Novalesa |
| Estb. |
aInstitut National de la Recherche Agronomique, UR1268 Biopolymères, Interactions, Assemblages, INRA, Equipe Interfaces Systèmes Dispersés, Rue de la Géraudière, 44316 Nantes Cedex 03, France
bLaboratoire de Physique des Solides, Université Paris-Sud, Bâtiment 510, 91405 Orsay, France |
| Abstract |
Single foam films made from mixtures of nonaggregated proteins and protein aggregates have been studied using a thin film balance apparatus. Their features (heterogeneity, stability and resistance to pressure change) are dependent on the aggregate size and on the ratio between nonaggregated proteins and protein aggregates. A phase diagram of these foam films has been drawn and a correlation of the structural properties of foam film and stability of real foams has been found. In particular, the formation of a gel-like network within the foam film coincides with the stability of the corresponding 3-D foams. |
| Magazine |
Colloids and Surfaces B: Biointerfaces 49 (2006) 40–48 |
| Year |
2006 |
| Autors |
C. Larréa, W. Mulderb, R. Sanchez-Vioquea, J. Lazkoa,S. Bérota,J. Guéguena and Y. Popineaua |
| Estb. |
aINRA, Unité de Recherche sur les Protéines Végétales et leurs Interactions, BP 71627, 44316 Nantes Cedex 3, France
bATO-DLO, P.O. Box 17, NL-6700 AA Wageningen, The Netherlands |
| Abstract |
Two hydrolysis methods used to obtain rapeseed isolate derivates were compared: chemical hydrolysis performed under alkaline conditions and pepsic proteolysis performed under acidic conditions. The mean molecular weights obtained for the hydrolysates varied from 26 to 2.5 kDa, depending on the level of hydrolysis. Further characterisation showed that, at the same level of hydrolysis, the chemical hydrolysates differed by their charges and hydrophobicity from those derived from enzymatic digestion. Analysis of the foaming properties showed, for both cases, that a limited degree of hydrolysis, around 3%, was sufficient to optimise the foaming properties of the isolate despite the different physicochemical properties of the peptides generated. The study of foaming properties at basic, neutral and acidic pHs showed that the hydrolysate solutions yielded dense foams which drained slowly and which maintained a very stable volume under the three pH conditions tested. |
| Magazine |
Colloids and Surfaces A:Physicochem. Eng. Aspects 330(2008)96-102 |
| Year |
2008 |
| Autors |
Bénédicte Rulliera, Bruno Novalesa and Monique A.V. Axelosa |
| Estb. |
a Institut National de la Recherche Agronomique, UR1268 Biopolymères, Interactions, Assemblages, INRA, Equipe Interfaces Systèmes Dispersés, Rue de la Géraudière, 44316 Nantes Cedex 03, France |
| Abstract |
Our paper aims at determining the respective part of protein aggregates and non-aggregated proteins in the foam formation and stability of β-lactoglobulin. We report results on fractal aggregates formed at neutral pH and strong ionic strength (aggregates size from 30 to 190 nm). Pure aggregates and mixtures of non-aggregated/aggregated proteins at varying ratios were used. The capacity of aggregates to form and stabilize foams has been studied in relation with their ability to absorb at air/water interfaces. Our results show that protein aggregates are not able by themselves to improve the foaming properties but participate to a better foam stabilization in the presence of non-aggregated proteins. Non-aggregated proteins appear to be necessary to produce stable foams.We have shown that the amount and the size of aggregates had an influence on the drainage rate. |
| Magazine |
Journal of Colloid and Interface Science S0021-9797(10)00048-2 |
| Year |
2010 |
| Autors |
I. Schmidta, B. Novalesa, M.A.V. Axelosa and F. Bouéb |
| Estb. |
a UR1268 Biopolymères Interactions Assemblages, INRA, F-44300 Nantes, France
b Laboratoire Léon Brillouin, UMR 12 CNRS/CEA-IRAMIS, 91191 Gif-sur-Yvette Cedex |
| Abstract |
The foaming properties, foaming capacity and foam stability, of soluble complexes of pectin and a globular protein, napin, have been investigated with a “Foamscan” apparatus. Complementary, we also used SANS with a recent method consisting in an analogy between the SANS by foams and the neutron reflectivity of films to measure in situ film thickness of foams.
The effect of ionic strength, of protein concentration and of charge density of the pectin has been analysed. Whereas the foam stability is improved for samples containing soluble complexes, no effect has been noticed on the foam film thickness, which is almost around 315 Å whatever the samples. These results let us specify the role of each specie in the mixture: free proteins contribute to the foaming capacity, provided the initial free protein content in the bulk is sufficient to allow the foam formation, and soluble complexes slow down the drainage by their presence in the Plateau borders, which finally results in the stabilisation of foams. |
| Magazine |
|
| Year |
2007 |
| Autors |
Victor Pizones Ruiz-Henestrosaa, Cecilio Carrera Saancheza and Juan M.Rodriguez Patinoa |
| Estb. |
a Departamento de Ingenieria Quimica, Facultad de Quimica, Universidad de Sevilla, C/ Prof. Garcia Gonza´lez, 1, E-41012-Sevilla, Spain |
| Abstract |
In this contribution, we have analyzed the effect of different strategies, such as change of pH (5 or 7) or ionic strength (at 0.05 and 0.5 M), and addition of sucrose (at 1 M) and Tween 20 (at 1×10-4 M) on interfacial characteristics (adsorption, structure, dynamics of adsorption, and surface dilatational properties) and foam properties (foam capacity and stability) of soy globulins (7S and 11S at 0.1 wt %). We have observed that the adsorption (presence of a lag period, diffusion, and penetration at the air-water interface) of soy globulins depends on the modification in the 11S/7S ratio and on the level of association/dissociation of these proteins by varying the pH and ionic strength (I), the effect of sucrose on the unfolding of the protein, and the competitive adsorption between protein and Tween 20 in the aqueous phase. The rate of adsorption increases at pH 7, at high ionic strength, and in the presence of sucrose. The surface dilatational properties reflect the fact that soy globulin adsorbed films exhibit viscoelastic behavior but do not have the capacity to form a gel-like elastic film. The surface dilatational modulus increases at pH 7 and at high ionic strength but decreases with the addition of sucrose or Tween 20 into the aqueous phase. The rate of adsorption and surface dilatational properties (surface dilatational modulus and phase angle) during adsorption at the air-water interface plays an important role in the formation of foams generated from aqueous solutions of soy globulins. However, the dynamic surface pressure and dilatational modulus are not enough to explain the stability of the foam. |
| Magazine |
Food Hydrocolloids 25 (2011) 694e706 |
| Year |
2011 |
| Autors |
K. Rade-Kukic a, C. Schmitt a and H.M. Rawel b |
| Estb. |
aDepartment of Food Science and Technology, Nestlé Research Center, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26, Switzerland |
bInstitute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany |
| Abstract |
Whey proteins are widely used food ingredients due to their nutritional and functional properties (gelling, emulsifying, foaming). Owning to their structure (free thiol group, lysine residues, hydrophobic pocket), they can also be used as carriers for bioactives. In this study, conjugates between b-lactoglobulin (b-lg), and a bioactive metabolite from Brassicaceae vegetables, allyl isothiocyanate (AITC) were formed. Heat aggregation behavior (85 _C, 15 min), foaming and emulsifying properties of conjugates, at pH 4.0 and 7.1, were evaluated. Conjugates were formed by incubating b-lg (0.5 mM) with AITC (0.05e20 mM) in water at pH 8.5 and room temperature. AITC primarily reacted with b-lg’s free thiol group (KD 0.2 _ 0.1 mM) and thereafter with its amino groups (KD 10.8 _ 3.4 mM). AITC binding destabilized secondary and tertiary structure of b-lg at pH 7.1, whereas induced molten globule conformation at pH 4.0. Conjugation reduced the heat aggregation of b-lg at pH 7.1, while promoting it at pH 4.0. Conjugates adsorbed faster to air/water and oil/water interfaces at pH 4.0 than at pH 7.1. After 30 min, air/water surface tension was lower at pH 4.0 (47 mNm_1) than at pH 7.1 (57 mNm_1), while the surface tension of the oil/water interface was 8 mNm_1 at both pHs. Foams produced with b-lgeAITC conjugates at pH 4.0 exhibited higher volume and liquid stabilities compared to foams obtained at pH 7.1. Emulsions formed with conjugates at both pHs were destabilized by creaming due to flocculation, but coalescence was prevented. This study revealed that whey protein could potentially be used for the delivery of isothiocyanates in the formof foam or emulsionbased products. |
| Magazine |
International Dairy Journal 16(2006)275-284 |
| Year |
2006 |
| Autors |
Hakim Bouaouinaa, Anne Desrumauxa, Catherine Loisela and Jack Legrandb |
| Estb. |
a GEPEA-ENITIAA-UMR-CNRS 6144, Rue de la Géraudière, BP 82225, 44322 Nantes Cedex 03, France
b GEPEA-UMR-CNRS 6144, Université de Nantes, CRTT, BP 406, 44602 Saint-Nazaire Cedex, France |
| Abstract |
An ultra high-pressure homogenizer was used to treat whey protein isolate solutions (3%, w/w). The treated solutions (up to 300 MPa) were characterised for both physico-chemical properties (particle size distribution, surface hydrophobicity and structural conformation) and functional properties (solubility, foaming stability and interfacial rheology). Dynamic high-pressure treatment did not affect the conformation of the proteins (determined by micro-calorimetry, size-exclusion chromatography and electrophoretic technique). This treatment dissociated large protein aggregates leading to unmasking of the buried hydrophobic groups without affecting protein solubility. Interactions may then occur between these groups that enhance the viscoelasticity of airwater interfaces (assessed by drop tensiometry) and improve foam stability (evaluated by sparging method). Dynamic high-pressuretreated whey proteins showed better foaming and stabilising properties. |
| Magazine |
Food Hydrocolloids 21(2007)782-793 |
| Year |
2007 |
| Autors |
Juan M. Rodriguez Patinoa, José Minones Condea, Herminia Millan Linaresa, Justo J. Pedroche Jimenezb, Cecilio Carrera Sancheza, Victor Pizonesa and Francisco Millan Rodriguezb |
| Estb. |
a Departamento de Ingenieria Quimica, Facultad de Quimica, Universidad de Sevilla, C/. Prof. Garcia Gonzalez 1, 41012-Seville, Spain
b Departamento de Fisiologia y Tecnologia de Productos Vegetales, Instituto de la Grasa C.S.I.C. Avda, Padre Garcia Tejero, 4, 41012-Sevilla, Spain |
| Abstract |
Plant proteins are increasingly being used as an alternative to proteins from animal sources in human nutrition. In this contribution we are concerned with the analysis of interfacial (adsorption isotherm, rate of adsorption, and surface dilatational properties) and foaming characteristics (foaming power and foam stability) of a sunflower protein isolate (SPI) and its hydrolysates with different degrees of hydrolysis (DH), as a function of the protein concentration in aqueous solution. Caseinate has been utilized as a protein of reference. We have observed that the adsorption and foaming power (foam capacity, gas and liquid retention in the foam, and foam density) increases with the protein concentration in the aqueous phase, depending on the DH. The adsorption kinetic at short adsorption time is diffusion controlled. However, the controlling mechanism at long-term adsorption is the penetration of the protein at the interface. A close relationship was observed between foaming and the rate of diffusion of the protein to the air–water interface. The foam stability— quantified by the relaxation time due to drainage (td) and disproportionation/coalescence (tdc)—correlates with the equilibrium surface pressure (πe) of the film adsorbed from aqueous solutions of the protein. |
| Magazine |
Food Hydrocolloids 19(2005)407-416 |
| Year |
2005 |
| Autors |
Cecilio Carrera Sancheza and Juan M. Rodriguez Patinoa |
| Estb. |
a Departamento de Ingenieria Quimica, Facultad de Quimica, Universidad de Sevilla, C/, Prof. Garcia Gonzalez 1, 41012 Seville, Spain |
| Abstract |
The foaming and emulsifying characteristics of proteins are important attributes during the production stage, storage, transport, and consumer perception of quality (appearance) of food dispersions (emulsions and foams). In this contribution, we are concerned with the analysis of interfacial, foaming, and emulsifying characteristics of a typical milk protein (sodium caseinate) as a function of protein concentration in aqueous solution (C, % w/w). We have observed that there exists close relationships between foaming (power of foaming, foam capacity, foam density, and foam conductivity) and the rate of diffusion (slope of π vs. t1/2) of caseinate to the air–water interface. The foam stability (quantified by the relaxation time (t) due to drainage and disproportionation/collapse) correlates linearly with the equilibrium surface pressure (πe) of aqueous solutions of caseinate. At surface pressures lower than that of monolayer saturation (at C < 1×10-3%, w/w) the foaming is zero. The emulsifying capacity (quantified by the droplet size and the specific surface area) was correlated with the protein concentration in solution (surface pressure at equilibrium). Coalescence was observed only at the lower caseinate concentration in solution (C < 0.1%, w/w). As a coherent protein layer (multilayer) saturates the interface, at higher protein concentrations, the emulsion instability is due to flocculation and/or creaming. The coalescence and creaming rates correlate well with the protein concentration in solution (thus with the surface pressure and/or surface dilatational modulus). |
| Magazine |
J. Agric. Food Chem. 2005, 53, 9089-9099 |
| Year |
2005 |
| Autors |
CHRISTOPHE SCHMITT a, CLAUDINE BOVAY a and PHILIPPE FROSSARD a |
| Estb. |
a Nestle´ Research Center, Department of Food Science, Vers-chez-les-Blanc, CH-1000 Lausanne 26, Switzerland |
| Abstract |
The formation of conjugates between â-lactoglobulin and acacia gum based on electrostatic complexes formed at pH 4.2 was investigated upon dry-state incubation for up to 14 days at 60 °C and 79% relative humidity (RH). By means of SEC-HPLC and RP-HPLC, it was shown that the â-lactoglobulin incubated alone was able to form polymers with molecular masses higher than 200 kDa until 50% of the initial monomeric protein disappeared after 14 days. In the presence of acacia gum at initial protein to polysaccharide weight mixing ratios of 2:1 and 1:2, only 35% of the initial â-lactoglobulin monomers disappeared after 14 days. Using RP-HPLC, an apparent reaction order of 2 was found for the disappearance of monomeric â-lactoglobulin both in the presence or absence of acacia gum. However, the reaction rate was faster in the absence of acacia gum. SDS-PAGE electrophoresis with silver staining confirmed the formation of â-lactoglobulin/acacia gum conjugates. The solubility curves of the incubated â-lactoglobulin showed a minimum around pH 4-5. By contrast, the minimum of solubility of the â-lactoglobulin/acacia gum incubated mixtures shifted to lower pH values compared to initial mixtures. The conjugates exhibited higher foam capacity than the incubated protein as well as lower equilibrium air/water surface tension. Conjugation at ratio 1:2 led to increased interfacial viscosity (300 mN s m-1 at 0.01 Hz) compared to â-lactoglobulin alone (100 mN s m-1 at 0.01 Hz), but similar interfacial elasticity (30-40 mN m-1). The foam capacity of the conjugates was significantly higher than that of the incubated â-lactoglobulin as well as foam expansion and drainage time, especially at pH 5.3, i.e., higher than the pH of formation of the conjugates. |
| Magazine |
Food Hydrocolloids 23 (2009) 1864–1876 |
| Year |
2009 |
| Autors |
Krastanka G. Marinovaa, Elka S. Bashevaa, Boriana Nenovaa, Mila Temelskaa, Amir Y. Mirarefib, Bruce Campbellb and Ivan B. Ivanova |
| Estb. |
a Laboratory of Chemical Physics & Engineering, Faculty of Chemistry, Sofia University, 1 James Bourchier Ave., 1164 Sofia, Bulgaria
b Kraft Foods Global Inc., Technology Center, 801 Waukegan Road, Glenview, IL 60025, U.S.A |
| Abstract |
We explored the foaming behavior of the two main types of milk proteins: flexible caseins and globular whey proteins. Direct foam comparison was complemented with measurements in model experiments such as thin foam films, dynamic surface tension, and protein adsorption. Foaming was studied as a function of pH (from below to above isoelectric point, pI) and range of ionic strengths. Maximum foamability was observed near pI ≈ 4.2 for WPC in contrast to sodium caseinate which had minimum foaming near pI = 4.6. Good foamability behavior correlated well with an increased adsorption, faster dynamic surface tension decrease and increased film lifetime. Differences in the stability of the foams and foam were explained with the different molecular structure and different aggregation behavior of the two protein types. Far from its isoelectric pI, casein adsorption layers are denser and thicker thus ensuring better stabilization. Added electrolyte increased further the adsorption and the repulsion between the surfaces (probably by steric and/or osmotic mechanism). In contrast the globular molecules of WPC probably could not compact well to ensure the necessary films and foams stabilization far from pI, even after electrolyte addition. |
| Magazine |
Food Hydrocolloids 22(2008)1298-1309 |
| Year |
2008 |
| Autors |
José M. Alvarez Gomeza, Victor Pizones Ruiz Henestrosaa, Cecilio Carrera Sancheza and Juan M. Rodriguez Patinoa |
| Estb. |
a Departamento de Ingenieria Quimica, Facultad de Quimica, Universidad de Sevilla, C/Prof. Garcia Gonzalez, 1, 41012 Sevilla, Spain |
| Abstract |
Foam formation and foam stability are criteria of primary importance for many aerated food formulations because consumer perception of quality is influenced by appearance. In this work, we have studied the effect of emulsifier concentration and protein/lipid ratio on the adsorption and foaming characteristics of mixed β-lactoglobulin and diglycerol ester (diglycerol-monolaurate and diglycerolmonostearate) aqueous solutions. The temperature, pH, and ionic strength were maintained constant at 20 °C, 7, and 0.05 M, respectively. The surface pressure isotherm of the mixed systems depended on the emulsifier concentration in solution and the protein/ lipid ratio in the mixture. The saturation of the interface by the protein or lipid has a significant effect on the foaming capacity of mixed protein and lipid aqueous solutions. We have observed that there exist close relationships between foaming and the rate of diffusion of mixed β-lactoglobulin and diglycerol esters to the air–water interface. For a particular system the overall foam destabilization (the halflife time of the foam) and the individual destabilization processes (drainage, disproportionation, and coalescence) depend on the lipid, the protein and lipid concentrations, and the protein/lipid ratio in the mixture. The results for β-lactoglobulin+diglycerol ester aqueous solutions also confirm that there exists a relationship between the half-life time of volume of liquid drained from the foam (θ1/2) and the long-term surface pressure. However, a general correlation between foam stability and surface dilatational properties was not clearly reflected in this study. |
| Magazine |
|
| Year |
|
| Autors |
Sabrina RAMI-SHOJAEIa, Corinne VACHIER-MAMMARb and Christophe SCHMITTa |
| Estb. |
a Nestlé Research Center,PO Box 44 Vers-chez-les-Blanc, 1000 Lausanne Suisse
b Centre de Mathématiques et Leurs Applications,Ecole Normale Sup´erieure de Cachan 61, av. du Pt Wilson, 94235 Cachan France |
| Abstract |
Aqueous foams occur in several industrial applications. One of the challenging issues in foams study is to evaluate the air bubbles stability. This problem is addressed in the present work using sequences of 2D macroscopic images of aqueous foams carried out in a glass column. Throughout the time, foams state changes: bubbles may appear, grow or disappear in the focal plane, adjacent bubbles may merge together... A precise analysis of the bubbles time evolution gives precious informations for characterizing foams. Of course, a manual treatment of the sequences is not possible since they contain hundreds of bubbles.
A very precise description of foams may be achieved by an automatic analysis of the macroscopic images: this is the object of the present study. We propose to analyze the size evolution of the bubbles throughout the sequence. At each time, bubbles size distribution is computed using a granulometry combining a scale-space chaining of the bubbles and a hierarchical segmentation procedure. Sequentially, a time chaining of the bubbles is achieved allowing the detection of the topological modifications of the foam structure in the 2D focal plan. Lastly, the size-time evolution of the bubbles is entirely memorized in a (2D + t) graph structure which is finally used for characterizing foams. Several parameters are calculated such average bubble diameter, bubble number or inter-bubble surface. These descriptors have been tested on a large range of foams of different types, each foam being studied several times in order to test the reproducibility of the analysis. Conducted experiments largely prove the pertinence of the developed approach. |
乳液
| Magazine |
International Dairy Journal 17 (2007) 889–895 |
| Year |
2006 |
| Autors |
C. Vanderghema, S. Danthinea, C. Bleckera and C. Deroannea |
| Estb. |
a Unité de Technologie des Industries Agro-alimentaires,Fac Univ des Sci. Agronomiques de Gembloux,Passage des Déporte 2B-5030 Gembloux,Belgium |
| Abstract |
The effect of the addition of the total proteose-peptone (TPP) fraction on some physico-chemical properties of recombined cream was studied. Oil-in-water emulsions, 30% or 20% (w/w) fat, were prepared using only the dairy components buttermilk, milkfat and TPP. The effect of different concentrations of TPP on droplet size, creaming stability, flow behaviour, viscosity and whippability of recombined creams was tested. Of the different creams, those containing 2% (w/w) or more TPP were more viscous, showed different flow behaviour, and had improved stability and whippability compared with the other creams. The modifications in physico-chemical properties appeared to be driven by changes in particle size distribution caused by droplet aggregation. The percentage of fat also influenced the properties of the final product. It may therefore be possible to obtain desirable modifications in recombined cream using only dairy ingredients. |
其他研究
| Magazine |
Ind. Eng. Chem. Res., 2003, 42 (3), pp 636–645 |
| Year |
2003 |
| Autors |
Daniel Pachoa and Graham Daviesa |
| Estb. |
a Department of Chemical Engineering, UMIST, P.O. Box 88, Manchester M60 1QD, U.K. |
| Abstract |
Electrical capacitance measurements have been used to detect the presence of oil foams and study their behavior, aiming for a better understanding of these systems and leading to the development of an improved foam control methodology. With the use of electrical capacitance, it was possible to identify the air/foam and foam/liquid interfaces. It was also demonstrated that accurate monitoring of the liquid content in the foam was possible. Data from capacitance measurements were processed to obtain information on the 2-D distribution of liquid in the foam as a function of time and also to recognize the main processes taking place during foam collapse. The application of capacitance measurements to the study of foam collapse has yielded promising results that encourage its further exploitation in the development of a novel methodology of foam control. |
| Magazine |
Langmuir, 2004, 20 (23), pp 10150–10158 |
| Year |
2004 |
| Autors |
B. Rippner Blomqvista,b, M. J. Ridoutc, A. R. Mackiec, T. Wärnheima, P. M. Claessonb and P. Wildec |
| Estb. |
a YKI, Institute for Surface Chemistry, P.O. Box 5607, 114 86 Stockholm, Sweden
b Department of Chemistry, Surface Chemistry, Royal Institute of Technology, Drottning Kristinas väg 51, 100 44 Stockholm, Sweden
c Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, United Kingdom |
| Abstract |
Nonequilibrium interfacial layers formed by competitive adsorption of β-lactoglobulin and the nonionic triblock copolymer PEO99-PPO65-PEO99 (F127) to the air-water interface were investigated in order to explain the influence of polymeric surfactants on protein film surface rheology and foam stability. Surface dilatationalandshear rheological methods, surface tension measurements,dynamicthin-film measurements, diffusion measurements (from fluorescence recovery after photo bleaching), and determinations of foam stability were used as methods. The high surface viscoelasticity, both the shear and dilatational, of the protein films was significantly reduced by coadsorption of polymeric surfactant. The drainage rate of single thin films, in the presence of β-lactoglobulin, increased with the amount of added F127, but equilibrium F127 films were found to be thicker than β-lactoglobulin films, even at low concentration of the polymeric surfactant. It is concluded that the effect of the nonionic triblock copolymer on the interfacial rheology of β-lactoglobulin layers is similar to that of low molecular weight surfactants. They differ however in that F127 increases the thickness of thin liquid films. In addition, the significant destabilizing effect of low molecular weight surfactants on protein foams is not found in the investigated system. This is explained as due to long-range steric forces starting to stabilize the foam films at low concentrations of F127. |
| Magazine |
Advances in Colloid and Interface Science 114-115(2005)239-251 |
| Year |
2005 |
| Autors |
R.J. Pugha |
| Estb. |
a Agricola Research Centre, Lulea° University, Sweden and Institute for Surface Chemistry (YKI), Box 5607, SE-114 86, Stockholm, Sweden |
| Abstract |
Several techniques are described in this review to study the structure and the stability of froths and foams. Image analysis proved useful for detecting structure changes in 2-D foams and has enabled the drainage process and the gradients in bubble size distribution to be determined. However, studies on 3-D foams require more complex techniques such as Mutiple-Light Scattering Methods, Microphones and Optical Tomography. Under dynamic foaming conditions, the Foam Scan Column enables the water content of foams to be determined by conductivity analysis. It is clear that the same factors, which play a role in foam stability (film thickness, elasticity, etc.) also have a decisive influence on the stability of isolated froth or foam films. Therefore, the experimental thin film balance (developed by the Bulgarian Researchers) to study thinning of microfilms formed by a concave liquid drop suspended in a short vertical capillary tube has proved useful. Direct measurement of the thickness of the aqueous microfilm is determined by a micro-reflectance method and can give fundamental information on drainage and thin film stability. It is also important to consider the influence of the mineral particles on the stability of the froth and it have been shown that particles of well defined size and hydrophobicity can be introduced into the thin film enabling stabilization/ destabilization mechanisms to be proposed. It has also been shown that the dynamic and static stability can be increased by a reduction in particle size and an increase in particle concentration. |
| Magazine |
|
| Year |
|
| Autors |
IT Concept |
| Estb. |
|
| Abstract |
This note makes a comparison between the behaviour of three foams, during their collapse phase, formed from three liquids containing respectively C12E6, SDS and OVALBUMIN.
In order to do this comparison easier, the surfactant concentrations have been determined so that these three liquids successively tested with the FOAMSCAN form, with the same bubbling conditions, the same volume of foam (about 100 cm3) during the same time (150 seconds). When the bubbling is stopped, the collapse phases take place which are quantified by the FOAMSCAN by recording the variations versus time of the three following parameters:
- volumes,
- drainage,
- conductivity at different heights.
These three parameters allow the differentiation between these three foams.
The instrument used is the FOAMSCAN |
| Magazine |
Journal of Colloid and Interface Science 346 (2010) 414–423 |
| Year |
2010 |
| Autors |
Enda Careya and Cosima Stubenraucha,b |
| Estb. |
a University College Dublin, School of Chemical and Bioprocess Engineering, Belfield, Dublin 4, Ireland
b Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany |
| Abstract |
An extensive study of the foaming properties of a surfactant mixture consisting of the non-ionic dodecyldimethyl phosphineoxide (C12DMPO) and the cationic dodecyltrimethyl ammonium bromide (C12TAB) with mixing ratios of C12DMPO:C12TAB = 1:0, 50:1, 1:1, 1:50, 0:1 is performed both above and below the critical micelle concentration. Foamability and foam stability were examined using the commercially available FoamScan (sparging), the standardised Ross-Miles (pouring) and a home-built winding (shaking) technique. The focus, however, was on FoamScan measurements as they allowed for the evaluation of the foam’s liquid content. The foamability and foam stability of C12TAB was found to be larger than that of C12DMPO. The foamability continually increased with increasing C12TAB content in the surfactant mixture, which reflects the reduction of the diffusion relaxation time (i.e. faster adsorption). Where possible correlations are drawn between the foam properties on the one hand and adsorption and foam film properties on the other hand, which were studied previously. Interestingly, the 1:1 mixture shows weak/negligible surfactant interactions but – counterintuitively – an increased foam stability compared to the single surfactant systems. However, at this ratio charge neutralization occurs, which leads to the formation of a Newton Black Film thus suggesting that the foam film type plays an important role in the foam stability. |
| Magazine |
Journal of Colloid and Interface Science 291(2005)236-243 |
| Year |
2005 |
| Autors |
Durga P. Acharyaa, José M. Gutiérrezb, Kenji Aramakia, Ken-ichi Aratanic and Hironobu Kuniedaa |
| Estb. |
a Graduate School of Environment and Information Sciences, Yokohama National University, Tokiwadai 79-7, Hodogaya-ku, Yokohama 240-8501, Japan
b Department of Chemical Engineering, Barcelona University, Martí i Franquès 1, 08028 Barcelona, Spain
c Chukyo Yushi Co., Ltd., 2-1 Tomikawa-cho, Nakagawa-ku, Nagoya 454-0037, Japan |
| Abstract |
Static and dynamic surface tension and interfacial rheological behavior of a novel anionic gemini-type surfactant without a spacer group, sodium 2,3-didodecyl-1,2,3,4-butane tetracarboxylate (GS), were investigated. Very low values for critical micelle concentration (8.9 × 10−5 M) as well as equilibrium surface tension (22.7 mN m−1) were observed for the aqueous solutions. Dynamic surface tension (DST) is very slow and less sensitive to the surfactant concentration than the conventional monomeric surfactant, suggesting the presence of a significant adsorption barrier for GS owing to a complicated molecular structure. Presence of a small concentration of GS in sodium dodecyl sulfate (SDS) solution shows a synergistic effect to form mixed micelles and lowers the cmc considerably. This synergism between GS and SDS and slow exchange of GS between bulk and interface create a rigid air–liquid interface of the SDS–GS solution, which is reflected in a higher elasticity value for the interface of the SDS–GS solution than for the SDS solution. It has been found that the presence of a small concentration of GS in SDS solution increases the foam stability noticeably. Although the stability of the wet foam is correlated with the film elasticity, the stability of dry foam cannot be explained in terms of film elasticity alone. |
| Magazine |
Chemical EngineeringScience |
| Year |
2009 |
| Autors |
Sylvain Guignota, Sylvain Faurea, Michele Vignes-Adlerb and Olivier Pitoisb |
| Estb. |
a Advanced Decontamination Processes Laboratory, Commissariat à l’Energie Atomique(CEA Marcoule), CEA, DEN, SPDE, LPAD, 30207 Bagnols sur Cèze, France
b Université Paris-Est, Laboratoire de Physique des Matériaux Divisés et des Interfaces, UMRCNRS8108, 5 bvd Descartes, 77454 Marne la Vallée Cedex2, France |
| Abstract |
This article describes a new strategy to modify the drainage behaviour of aqueous foams with solid nanoparticles. While for high particulate concentrations the liquid flow can be slowed down owing to viscosity effects, we show that much less concentrated systems, but possessing peculiar physicochem- ical properties, can also strongly modify the drainage behaviour. Taking advantage of the agglomerated state of pyrogenic silica in aqueous media, highly porous macro-particles are specifically prepared in the initial foaming solutions. It is shown that their typical size and their intrinsic yield-stress properties enable them to be captured by the bubbles during the foam generation stage and subsequently to be retained in the foam channels, according to a geometrical criterion based on the particle/bubble sizes ratio. The drainage curves of the foams display significant retention rates for the suspension during several hours, an effect that is enhanced for higher particles concentrations. This has been related to the high internal porosity and hydrophilic character of the macro-particles, acting as liquid-traps in the foam microstructure. |
| Magazine |
Colloid & Interface Science xxx (2010) xxx–xxx |
| Year |
2010 |
| Autors |
Cagri Üzüma, Nora Kristena and Regine von Klitzinga |
| Estb. |
a Stranski-Laboratorium für Physicalische und Theoritische Chemie, Technische Universität Berlin, Straße des 17, Juni 124, D-10623 Berlin, Germany |
| Abstract |
The review addresses the influence of polyelectrolytes on the statics and dynamics of thin liquid films. Both, changes of interfacial and bulk properties, contribute to the overall behaviour of thin films formed from aqueous polyelectrolyte solutions. Therefore, the chapter is separated into two parts: polyelectrolytes at film interfaces and polymers in film bulk. |
| Magazine |
Langmuir, 2008, 24 (22), pp 12849–12857 |
| Year |
2008 |
| Autors |
Marie-Hélène Ropersa, B. Novalesa, F. Bouéb and M. A. V. Axelosa |
| Estb. |
a INRA, BP 71627, F-44316 Nantes Cedex 3, France.
b Laboratoire Léon Brillouin, UMR 12 CNRS/CEA-IRAMIS, 91191 Gif-sur-Yvette Cedex, France |
| Abstract |
The binding of a cationic surfactant (hexadecyltrimethylammonium bromide, CTAB) to a negatively charged natural polysaccharide (pectin) at air-solution interfaces was investigated on single interfaces and in foams, versus the linear charge densities of the polysaccharide. Besides classical methods to investigate polymer/surfactant systems, we applied, for the first time concerning these systems, the analogy between the small angle neutron scattering by foams and the neutron reflectivity of films to measure in situ film thicknesses of foams. CTAB/pectin foam films are much thicker than the pure surfactant foam film but similar for high- and low-charged pectin/CTAB systems despite the difference in structure of complexes at interfaces. The improvement of the foam properties of CTAB bound to pectin is shown to be directly related to the formation of pectin-CTAB complexes at the air-water interface. However, in opposition to surface activity, there is no specific behavior for the highly charged pectin: foam properties depend mainly upon the bulk charge concentration, while the interfacial behavior is mainly governed by the charge density of pectin. For the highly charged pectin, specific cooperative effects between neighboring charged sites along the chain are thought to be involved in the higher surface activity of pectin/CTAB complexes. A more general behavior can be obtained at lower charge density either by using a low-charged pectin or by neutralizing the highly charged pectin in decreasing pH. |
| Magazine |
Journal of Colloid and Interface Science 333 (2009) 619–627 |
| Year |
2009 |
| Autors |
Enda Careya and Cosima Stubenraucha,b |
| Estb. |
a University College Dublin, School of Chemical and Bioprocess Engineering, Belfield, Dublin 4, Ireland
b Centre for Synthesis and Chemical Biology, SFI-Strategic Research Cluster in Solar Energy Conversion, University College Dublin, Belfield, Dublin 4, Ireland |
| Abstract |
Foamability, foam stability and the liquid volume of aqueous foams stabilized by dodecyltrimethylammonium bromide (C12TAB) are studied. The foams are generated with a sparging method at different gas flow rates and surfactant concentrations. It is found that at concentrations c ≥ cmc drainage dominates foam destruction while at c < cmc additional processes lead to a dramatic decrease in foam stability. Qualitatively similar results are obtained with the Ross–Miles (pouring) method and the winding (shaking) method, respectively. Increasing the gas flow rate of the sparging method at a fixed surfactant concentration, one observes a decrease in the time required for the production of 60 ml foam, while the liquid volume of the generated foam increases. On the other hand, an increase of the surfactant concentration at a fixed gas flow rate leads to an increase in the required foaming time with a plateau at c ≥ cmc, while the liquid volume of the generated foam decreases. Finally, the influence of small impurities is also tested and it is found that small amounts of impurities (“as received sample”) lead to a significant increase of both the foamability and the stability of foams stabilized by C12TAB. The obtained results are discussed in terms of the different processes leading to foam destruction and a comparison between the three different methods is made. Whenever possible and feasible, the correlation between single surfaces, single foam films and foams is addressed. |
| Magazine |
Langmuir, 2010, 26 (8), pp 5329–5334 |
| Year |
2010 |
| Autors |
Bruno Novalesa, Alain Riaublanca, Laurence Navaillesb, Bérénice Houinsou Houssoua, Cédric Gaillarda, Frédéric Nalletb and Jean-Paul Douliezb |
| Estb. |
a UR1268 Biopolyméres Interactions Assemblages, INRA, équipe Interfaces et Systèmes Dispersés, rue de la Géraudiére, F-44316 Nantes, France
b CNRS, Centre de recherche Paul-Pascal, 115 avenue Albert-Schweitzer, F-33600 Pessac, France |
| Abstract |
We report on dispersions of fatty acid-lysine salts in aqueous solutions which are further used to produce foams. The alkyl chain length is varied from dodecyl to stearic. In aqueous solutions, the lysine salt of the dodecyl chain yields an isotropic solution, probably micelles, whereas for longer alkyl chains, vesicles formed but crystallized upon resting at room temperature or when kept at 4 °C. Solid-stateNMRshowed that in vesicles fatty acids are embedded in a lamellar arrangement passing from a gel to a fluid state upon heating; the transition temperature at which it occurs was determined by DSC. Those results are confirmed by small-angle neutron scattering which also give additional information on the bilayer structure. Incredibly stable foams are obtained using the palmitic acid/Lys salt whereas for other alkyl chain length, poor or no foam is formed.Weconclude that the foamability is related to the phase behavior in aqueous solution. |
| Magazine |
Langmuir, 2008, 24 (1), pp 62–68 |
| Year |
2008 |
| Autors |
Bruno Novalesa, Laurence Navaillesb, Monique Axelosa, Frédéric Nalletb and Jean-Paul Doulieza |
| Estb. |
a UR1268, Biopolymères Interactions Assemblages, INRA, Équipe Interfaces et Systèmes Dispersés, rue de la Géraudière, F-44316 Nantes, France
b CNRS, Centre de Recherche Paul-Pascal, 115 Avenue Albert-Schweitzer, F-33600 Pessac, France |
| Abstract |
We report the dispersions of a fatty acid and hydroxyl derivative salts in aqueous solutions that were further used to produce foams and emulsions. The tetrabutyl-ammonium salts of palmitic acid, 12-hydroxy stearic acid, and omega-hydroxy palmitic acid formed isotropic solutions of micelles, whereas the ethanolamine salts of the same acids formed turbid birefringent lamellar solutions. The structure and dimension of those phases were confirmed by smallangle neutron scattering and NMR. Micelles exhibited a surprisingly small radius of about 20 Å, even for hydroxyl fatty acids, suggesting the formation of hydrogen bonds between lipids in the core of the micelles. In the case of ethanolamine salts of palmitic and 12-hydroxy stearic acids, the lipids were arranged in bilayers, with a phase transition from gel to fluid upon heating, whereas for omega-hydroxy palmitic acid, monolayers formed in accordance with the bola shape of this lipid. Foams and emulsions produced from ethanolamine salt solutions were more stable than those obtained from tetrabutyl-ammonium salt solutions. We discuss these results in terms of counterion size, lipid molecular shape, and membrane curvature. |
| Magazine |
Materials Letters |
| Year |
2011 |
| Autors |
Juanli Yu a, Jinlong Yang a, Hexin Li a, Xiaoqing Xi a, and Yong Huang a |
| Estb. |
a State Key Lab of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China |
| Abstract |
The stability of bubbles and the microstructures of sintered Si3N4 ceramic foams produced by direct foaming method were investigated. The bubbles produced by short-chain amphiphiles (propyl gallate) have higher stability as compared with that produced by long-chain surfactants (TritonX-114). Si3N4 ceramic foams using shortchain amphiphile are particle-stabilized one, the pore cells are spherical and closed, and cell surfaces are smooth and dense. The pore cells of sintered Si3N4 ceramic foams using TritonX-114 foaming are coarse and large, and pore cells are polyhedral. High gaspressure sintering is conducive to the development of the whisker-like microstructures in Si3N4 ceramic foams. The sintered Si3N4 ceramic foams with the whisker-like microstructure are quite promising for improving the mechanical strength of the ceramics by a simple and safe way. |
| Magazine |
Journal of Colloid and Interface Science 268(2003)221-229 |
| Year |
2003 |
| Autors |
Davide Beneventia,b, Robert J. Pughc, Bruno Carréb and Alessandro Gandinia |
| Estb. |
a Ecole Française de Papeterie et des Industries Graphiques (INPG), BP 65, 38402 St. Martin d'Hères, France
b Centre Technique du Papier, Ressources Fibreuses, Domaine Universitaire, B.P. 251, 38044 Grenoble Cedex 9, France
c Institute for Surface Chemistry, Box 5607, SE-114 86, Stockholm, Sweden |
| Abstract |
The dynamic surface tension (DST) and the surface viscoelastic modulus of sodium oleate aqueous solutions at different concentrations were measured using an image analysis tensiometer based on the oscillating bubble technique. The diffusion coefficient of oleate moieties was calculated from DST measurements and the surface viscoelastic modulus using the Langmuir–Szyszkowski and the diffusion-controlled adsorption models. The viscoelastic moduli obtained from model calculations were compared with the corresponding experimental values. The diffusion coefficient of C12(EO)6 in water and the parameters of the Langmuir–Szyszkowski adsorption isotherm were taken from the literature and used to calculate the surface viscoelastic modulus of its aqueous solutions at different concentrations. The foaming properties of both C12(EO)6 and sodium oleate solutions, viz., the foam conductance and the water volume fraction in the foam, were measured using a commercial Foamscan device. Foaming experiments with C12(EO)6 and sodium oleate solutions were carried out either under static conditions; i.e., the foam conductance and the water volume fraction were measured as a function of time after the generation of a fixed volume of foam, or under dynamic conditions; i.e., the foam conductance and the water volume fraction were measured during foam formation. The variations in the foam permeability as a function of surfactant concentration were related to the viscoelastic properties of the air/water interface and to the presence of micelles in the foam films. With foams in which the water volume fraction was higher than 0.05, the foam electrical conduction could be described using a simple parallel resistor model and their conductance measurements were related to the foam water volume fraction. The results related to water drainage under static conditions were used to interpret water drainage under dynamic conditions. Preliminary conjectures on the influence of foam permeability and water volume fraction on the yield of the flotation deinking process were drawn from these results. |
| Magazine |
Colloids and Surfaces A: Physicochem. Eng. |
| Year |
2011 |
| Autors |
S. Faure a, S.Vollanda, Q.Crouzetb, G.Boutevin b, and C.Loubatb |
| Estb. |
a CEA, Nuclear Energy Division/Center of Marcoule DTCD/SPDE/LPAD, Bagnols/Cèze, France |
b SPECIFIC POLYMERS, Clapiers (34), France |
| Abstract |
This paper describes how to synthesise new hydrophobic foaming particles by grafting short fluorinated phosphonic acid (3 carbons) on commercial hydrophilic alumina particles. The short grafting fluorinated agent CF3–CFH–CF2–P(O)(OH)2 preparation is detailed. The corresponding hydrophobic foaming particles are easily prepared by acidic–alkaline grafting using this molecule. “Bikerman foams” are easily generated by air sparging through an aqueous suspension of fluorinated alumina particles. The expansion ratio of the foam could be greater than 20. On a free drainage configuration, relatively dry foams were obtained with a high life time, more than 10h. The mechanism of stabilisation proposed to describe the role of the particles is based on the attachment of the particles at the air–water interface. |
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