The Experts below are selected from a list of 12423 Experts worldwide ranked by ideXlab platform
Sun-min Byun - One of the best experts on this subject based on the ideXlab platform.
-
Modification and Minimization of Spinel(Al_2O_3·xMgO) Inclusions Formed in Ti-Added Steel Melts
Metallurgical and Materials Transactions B, 2010Co-Authors: Sung-koo Jo, Sun-min ByunAbstract:High-melting-point inclusions such as spinel(Al_2O_3· x MgO) are known to promote clogging of the submerged entry nozzle (SEN) in a continuous caster mold. In particular, Ti-alloyed steels can have severe nozzle clogging problems, which are detrimental to the slab surface quality. In this work, the Thermodynamic role of Ti in steels and the effect of Ca and Ti addition to the molten austenitic stainless steel deoxidized with Al on the formation of Al_2O_3· x MgO spinel inclusions were investigated. The sequence of Ca and Ti additions after Al deoxidation was also investigated. The inclusion chemistry and morphology according to the order of Ca and Ti are discussed from the standpoint of spinel formation. The Thermodynamic interaction parameter of Mg with respect to the Ti alloying element was determined. The element of Ti in steels could contribute to enhancing the spinel formation, because Ti accelerates Mg dissolution from the MgO containing refractory walls or slags because of its high Thermodynamic Affinity for Mg $$ ( {e_{\text{Mg}}^{\text{Ti}} = - 0. 9 3 3}). $$ Even though Ti also induces Ca dissolution from the CaO-containing refractory walls or slags because of its Thermodynamic Affinity for Ca $$ \left( {e_{\text{Ca}}^{\text{Ti}} = - 0.119} \right), $$ dissolved Ca plays a role in favoring the formation of calcium aluminate inclusions, which are more stable Thermodynamically in an Al-deoxidized steel. The inclusion content of steel samples was analyzed to improve the understanding of fundamentals of Al_2O_3· x MgO spinel inclusion formation. The optimum processing conditions for Ca treatment and Ti addition in austenitic stainless steel melts to achieve the minimized spinel formation and the maximized Ti-alloying yield is discussed.
-
Modification and Minimization of Spinel(Al_2O_3·xMgO) Inclusions Formed in Ti-Added Steel Melts
Metallurgical and Materials Transactions B, 2010Co-Authors: Sung-koo Jo, Sun-min ByunAbstract:High-melting-point inclusions such as spinel(Al_2O_3· x MgO) are known to promote clogging of the submerged entry nozzle (SEN) in a continuous caster mold. In particular, Ti-alloyed steels can have severe nozzle clogging problems, which are detrimental to the slab surface quality. In this work, the Thermodynamic role of Ti in steels and the effect of Ca and Ti addition to the molten austenitic stainless steel deoxidized with Al on the formation of Al_2O_3· x MgO spinel inclusions were investigated. The sequence of Ca and Ti additions after Al deoxidation was also investigated. The inclusion chemistry and morphology according to the order of Ca and Ti are discussed from the standpoint of spinel formation. The Thermodynamic interaction parameter of Mg with respect to the Ti alloying element was determined. The element of Ti in steels could contribute to enhancing the spinel formation, because Ti accelerates Mg dissolution from the MgO containing refractory walls or slags because of its high Thermodynamic Affinity for Mg $$ ( {e_{\text{Mg}}^{\text{Ti}} = - 0. 9 3 3}). $$ Even though Ti also induces Ca dissolution from the CaO-containing refractory walls or slags because of its Thermodynamic Affinity for Ca $$ \left( {e_{\text{Ca}}^{\text{Ti}} = - 0.119} \right), $$ dissolved Ca plays a role in favoring the formation of calcium aluminate inclusions, which are more stable Thermodynamically in an Al-deoxidized steel. The inclusion content of steel samples was analyzed to improve the understanding of fundamentals of Al_2O_3· x MgO spinel inclusion formation. The optimum processing conditions for Ca treatment and Ti addition in austenitic stainless steel melts to achieve the minimized spinel formation and the maximized Ti-alloying yield is discussed.
-
Modification and Minimization of Spinel(Al2O3·xMgO) Inclusions Formed in Ti-Added Steel Melts
Metallurgical and Materials Transactions B, 2010Co-Authors: Chang-woo Seo, Seon-hyo Kim, Min-oh Suk, Sun-min ByunAbstract:High-melting-point inclusions such as spinel(Al2O3·xMgO) are known to promote clogging of the submerged entry nozzle (SEN) in a continuous caster mold. In particular, Ti-alloyed steels can have severe nozzle clogging problems, which are detrimental to the slab surface quality. In this work, the Thermodynamic role of Ti in steels and the effect of Ca and Ti addition to the molten austenitic stainless steel deoxidized with Al on the formation of Al2O3·xMgO spinel inclusions were investigated. The sequence of Ca and Ti additions after Al deoxidation was also investigated. The inclusion chemistry and morphology according to the order of Ca and Ti are discussed from the standpoint of spinel formation. The Thermodynamic interaction parameter of Mg with respect to the Ti alloying element was determined. The element of Ti in steels could contribute to enhancing the spinel formation, because Ti accelerates Mg dissolution from the MgO containing refractory walls or slags because of its high Thermodynamic Affinity for Mg \( ( {e_{\text{Mg}}^{\text{Ti}} = - 0. 9 3 3}). \) Even though Ti also induces Ca dissolution from the CaO-containing refractory walls or slags because of its Thermodynamic Affinity for Ca \( \left( {e_{\text{Ca}}^{\text{Ti}} = - 0.119} \right), \) dissolved Ca plays a role in favoring the formation of calcium aluminate inclusions, which are more stable Thermodynamically in an Al-deoxidized steel. The inclusion content of steel samples was analyzed to improve the understanding of fundamentals of Al2O3·xMgO spinel inclusion formation. The optimum processing conditions for Ca treatment and Ti addition in austenitic stainless steel melts to achieve the minimized spinel formation and the maximized Ti-alloying yield is discussed.
Maria G Semenova - One of the best experts on this subject based on the ideXlab platform.
-
Structural and Thermodynamic features of covalent conjugates of sodium caseinate with maltodextrins underlying their functionality.
Food & Function, 2011Co-Authors: N. V. Grigorovich, Maria G Semenova, Larisa E Belyakova, Anna S Antipova, D. V. Moiseenko, M. S. Anokhina, Yu. N. Polikarpov, N. Korica, B. A. BaranovAbstract:The sodium caseinate (SCN)–maltodextrin (MD) covalent conjugates were prepared by a food-grade process involving the first step of the Maillard reaction. The covalent conjugates were prepared with different weight ratios of biopolymers (RMD : SCN = 0.4; 1; 2; 5) in the system using maltodextrins of strongly different dextrose equivalents (DE), i.e., DE = 2 and 10. We have observed that the covalent conjugation of SCN with MD, in contrast to their simple mixing, improved the protein solubility in an aqueous medium in a wide pH range that was more pronounced in the vicinity of the SCN isoelectric point (pH 3.8–4.4). The extent of SCN solubility was mainly governed by the weight/molar ratio of the biopolymers in the covalent conjugates, RMD : SCN. Data of static multiangle laser light scattering showed that the revealed increase in the solubility of the conjugates could be predominantly attributable to the dramatic increase in their Thermodynamic Affinity for an aqueous medium. Which was most pronounced for the maltodextrin with the higher DE (DE = 10). The direct relationship between the increase in the solubility of the conjugates and the increase in their foaming ability, as compared against SCN, has been revealed as a rule both at neutral pH and at the pI. In addition, the found improvement in the protein foaming ability was also defined by both the weight/molar ratio (RMD : SCN) and the dextrose equivalent of the maltodextrins attached to the protein.
-
Analysis of light scattering data on the sodium caseinate assembly as a response to the interactions with likely charged anionic surfactant
Food Hydrocolloids, 2007Co-Authors: Maria G Semenova, Larisa E Belyakova, Anna S Antipova, Yu. N. Polikarpov, Ivana Stankovic, M. S. AnokhinaAbstract:We report on the modification of the parameters of sodium caseinate nanoparticles, measured basically by static and dynamic light scattering (the weight-average molar mass M w ; the radius of gyration R G , the hydrodynamic radius R h , their ratio (p = R G /R h ), reflecting the shape of the scattering particles; and the Thermodynamic Affinity for an aqueous medium (the second virial coefficient A 2 )), as a response to the interactions with the likely charged anionic surfactant-CITREM (the equimass mixtures of the esters of the stearic and palmitic acids with a citric acid) over a wide range of the surfactant low concentrations at pH 7.2. We found that the protein association, induced by the interactions with the likely charged anionic surfactant, was most pronounced at the medium value of the ionic strength under the ionic strength variation from 0.005 to 0.1 M, namely, at 0.05 M. The detailed dependence of the parameters of the surfactant-modified sodium caseinate on the CITREM concentration allowed recognizing the three concentration regions with the specific parameters of the complex (protein+surfactant) nanoparticles at the ionic strength that is peculiar to the most marked protein association (0.05 M). The first concentration region is at C CITREM
-
Influence of maltodextrins with different dextrose equivalent on the Thermodynamic properties of legumin in a bulk and at the air–water interface
Colloids and Surfaces B: Biointerfaces, 1999Co-Authors: Maria G Semenova, Larisa E Belyakova, Anna S Antipova, Maria A JubanovaAbstract:Abstract This paper presents the influence of the potato maltodextrins with different dextrose equivalent (DE 2, 6 and 10) on the legumin Thermodynamic properties in the bulk aqueous medium and at the air–water interface both in the simple mixed solutions and under the covalent complex (conjugate) formation (by the Maillard reaction), at pH 7.0 and ionic strength of 0.05 mol dm−3. The weak net attractive interaction between legumin and maltodextrin has been found in an aqueous medium by both the light scattering and the mixing calorimetry methods. On the basis of both the mixing and differential scanning calorimetry data a hydrogen bonding is supposed to be fundamental for this interaction. It was found that these attractive interactions produced an increase in the protein hydrophilicity and consequently a decrease in the protein surface activity. The effect was more pronounced for the maltodextrin with the largest dextrose equivalent (DE 10). The covalent complexation between legumin and maltodextrin induced the change of the fine hydrophobic–hydrophilic balance in the protein globule due to both addition of the hydrophilicity of the covalently attached polysaccharide and the partial protein unfolding as a result of the such kind of attachment. The combined data of tensiometry, light scattering, mixing and differential scanning calorimetry demonstrated the importance of the maltodextrin polymerization (DE) in controlling both the protein hydrophilicity (Thermodynamic Affinity for the aqueous phase) and surface activity.
-
influence of maltodextrins with different dextrose equivalent on the Thermodynamic properties of legumin in a bulk and at the air water interface
Colloids and Surfaces B: Biointerfaces, 1999Co-Authors: Maria G Semenova, Larisa E Belyakova, Anna S Antipova, Maria A JubanovaAbstract:Abstract This paper presents the influence of the potato maltodextrins with different dextrose equivalent (DE 2, 6 and 10) on the legumin Thermodynamic properties in the bulk aqueous medium and at the air–water interface both in the simple mixed solutions and under the covalent complex (conjugate) formation (by the Maillard reaction), at pH 7.0 and ionic strength of 0.05 mol dm−3. The weak net attractive interaction between legumin and maltodextrin has been found in an aqueous medium by both the light scattering and the mixing calorimetry methods. On the basis of both the mixing and differential scanning calorimetry data a hydrogen bonding is supposed to be fundamental for this interaction. It was found that these attractive interactions produced an increase in the protein hydrophilicity and consequently a decrease in the protein surface activity. The effect was more pronounced for the maltodextrin with the largest dextrose equivalent (DE 10). The covalent complexation between legumin and maltodextrin induced the change of the fine hydrophobic–hydrophilic balance in the protein globule due to both addition of the hydrophilicity of the covalently attached polysaccharide and the partial protein unfolding as a result of the such kind of attachment. The combined data of tensiometry, light scattering, mixing and differential scanning calorimetry demonstrated the importance of the maltodextrin polymerization (DE) in controlling both the protein hydrophilicity (Thermodynamic Affinity for the aqueous phase) and surface activity.
-
Effect of decane or sodium decanoate on the Thermodynamics of globular protein solutions
Food Hydrocolloids, 1997Co-Authors: L. A. Wasserman, Maria G SemenovaAbstract:Abstract The elucidation of the effect of decane or sodium decanoate (models of the nonpolar or polar lipids) on the molecular parameters and Thermodynamic properties of proteins has been carried out in binary (protein-solvent) and ternary (protein-protein-solvent) aqueous solutions. Ovalbumin and 11S globulin, globular proteins of well-known structure, were considered. Light-scattering data manifest protein association in aqueous medium under the influence of both decane and sodium decanoate. Association of protein molecules in aqueous medium is higher under the influence of the nonpolar decane molecules. The Thermodynamic parameters for different types of pair interactions in the systems ( the second virial coefficients) were estimated from static light-scattering data in the binary and ternary aqueous solutions of biopolymers without and with decane or sodium decanoate. The values of the second virial coefficients obtainedfrom binary solutions exhibit high Thermodynamic Affinity of protein associates formed under the influence of decane or sodium decanoate for aqueous medium. Maximal Thermodynamic Affinity of the protein associates for the solvent was observed in the case of the polar sodium decanoate added to the proteins. The values of the cross second virial coefficients obtained from ternary solutions indicate that the addition of the nonpolar decane molecules to the proteins increases the strength of the Thermodynamically unfavorable interactions between protein molecules that are different in nature. On the other hand, the addition of polar sodium decanoate to the proteins leads to a decrease in the Thermodynamically unfavorable protein-protein pair interactions in aqueous medium. The influence of the decane or sodium decanoate on the conformational state of the proteins in aqueous medium was characterized by differential scanning microcalorimetry. The data obtained manifest significant changing of the conformational stability of the protein globule under the influence of decane or sodium decanoate. The character of this influence strongly depends on the nature of both the low-molecular-weight organic compounds and the proteins studied.
Sung-koo Jo - One of the best experts on this subject based on the ideXlab platform.
-
Modification and Minimization of Spinel(Al_2O_3·xMgO) Inclusions Formed in Ti-Added Steel Melts
Metallurgical and Materials Transactions B, 2010Co-Authors: Sung-koo Jo, Sun-min ByunAbstract:High-melting-point inclusions such as spinel(Al_2O_3· x MgO) are known to promote clogging of the submerged entry nozzle (SEN) in a continuous caster mold. In particular, Ti-alloyed steels can have severe nozzle clogging problems, which are detrimental to the slab surface quality. In this work, the Thermodynamic role of Ti in steels and the effect of Ca and Ti addition to the molten austenitic stainless steel deoxidized with Al on the formation of Al_2O_3· x MgO spinel inclusions were investigated. The sequence of Ca and Ti additions after Al deoxidation was also investigated. The inclusion chemistry and morphology according to the order of Ca and Ti are discussed from the standpoint of spinel formation. The Thermodynamic interaction parameter of Mg with respect to the Ti alloying element was determined. The element of Ti in steels could contribute to enhancing the spinel formation, because Ti accelerates Mg dissolution from the MgO containing refractory walls or slags because of its high Thermodynamic Affinity for Mg $$ ( {e_{\text{Mg}}^{\text{Ti}} = - 0. 9 3 3}). $$ Even though Ti also induces Ca dissolution from the CaO-containing refractory walls or slags because of its Thermodynamic Affinity for Ca $$ \left( {e_{\text{Ca}}^{\text{Ti}} = - 0.119} \right), $$ dissolved Ca plays a role in favoring the formation of calcium aluminate inclusions, which are more stable Thermodynamically in an Al-deoxidized steel. The inclusion content of steel samples was analyzed to improve the understanding of fundamentals of Al_2O_3· x MgO spinel inclusion formation. The optimum processing conditions for Ca treatment and Ti addition in austenitic stainless steel melts to achieve the minimized spinel formation and the maximized Ti-alloying yield is discussed.
-
Modification and Minimization of Spinel(Al_2O_3·xMgO) Inclusions Formed in Ti-Added Steel Melts
Metallurgical and Materials Transactions B, 2010Co-Authors: Sung-koo Jo, Sun-min ByunAbstract:High-melting-point inclusions such as spinel(Al_2O_3· x MgO) are known to promote clogging of the submerged entry nozzle (SEN) in a continuous caster mold. In particular, Ti-alloyed steels can have severe nozzle clogging problems, which are detrimental to the slab surface quality. In this work, the Thermodynamic role of Ti in steels and the effect of Ca and Ti addition to the molten austenitic stainless steel deoxidized with Al on the formation of Al_2O_3· x MgO spinel inclusions were investigated. The sequence of Ca and Ti additions after Al deoxidation was also investigated. The inclusion chemistry and morphology according to the order of Ca and Ti are discussed from the standpoint of spinel formation. The Thermodynamic interaction parameter of Mg with respect to the Ti alloying element was determined. The element of Ti in steels could contribute to enhancing the spinel formation, because Ti accelerates Mg dissolution from the MgO containing refractory walls or slags because of its high Thermodynamic Affinity for Mg $$ ( {e_{\text{Mg}}^{\text{Ti}} = - 0. 9 3 3}). $$ Even though Ti also induces Ca dissolution from the CaO-containing refractory walls or slags because of its Thermodynamic Affinity for Ca $$ \left( {e_{\text{Ca}}^{\text{Ti}} = - 0.119} \right), $$ dissolved Ca plays a role in favoring the formation of calcium aluminate inclusions, which are more stable Thermodynamically in an Al-deoxidized steel. The inclusion content of steel samples was analyzed to improve the understanding of fundamentals of Al_2O_3· x MgO spinel inclusion formation. The optimum processing conditions for Ca treatment and Ti addition in austenitic stainless steel melts to achieve the minimized spinel formation and the maximized Ti-alloying yield is discussed.
Andrew J Daugulis - One of the best experts on this subject based on the ideXlab platform.
-
Selecting polymers for two-phase partitioning bioreactors (TPPBs): Consideration of Thermodynamic Affinity, crystallinity, and glass transition temperature.
Biotechnology Progress, 2015Co-Authors: Stuart L Bacon, Andrew J Daugulis, Eric Charles Peterson, J. Scott ParentAbstract:Two-phase partitioning bioreactor technology involves the use of a secondary immiscible phase to lower the concentration of cytotoxic solutes in the fermentation broth to subinhibitory levels. Although polymeric absorbents have attracted recent interest due to their low cost and biocompatibility, material selection requires the consideration of properties beyond those of small molecule absorbents (i.e., immiscible organic solvents). These include a polymer's (1) Thermodynamic Affinity for the target compound, (2) degree of crystallinity (wc ), and (3) glass transition temperature (Tg ). We have examined the capability of three Thermodynamic models to predict the partition coefficient (PC) for n-butyric acid, a fermentation product, in 15 polymers. Whereas PC predictions for amorphous materials had an average absolute deviation (AAD) of ≥16%, predictions for semicrystalline polymers were less accurate (AAD ≥ 30%). Prediction errors were associated with uncertainties in determining the degree of crystallinity within a polymer and the effect of absorbed water on n-butyric acid partitioning. Further complications were found to arise for semicrystalline polymers, wherein strongly interacting solutes increased the polymer's absorptive capacity by actually dissolving the crystalline fraction. Finally, we determined that diffusion limitations may occur for polymers operating near their Tg , and that the Tg can be reduced by plasticization by water and/or solute. This study has demonstrated the impact of basic material properties that affects the performance of polymers as sequestering phases in TPPBs, and reflects the additional complexity of polymers that must be taken into account in material selection.
-
a framework to predict and experimentally evaluate polymer solute Thermodynamic Affinity for two phase partitioning bioreactor tppb applications
Journal of Chemical Technology & Biotechnology, 2014Co-Authors: Stuart L Bacon, Scott J Parent, Andrew J DaugulisAbstract:BACKGROUND Selection of a polymer for two-phase partitioning bioreactor (TPPB) applications has previously been limited to heuristic approaches. However, recent interest has focused on first principles' selection methods based on polymer crystallinity, glass transition temperature and polymer–solute Thermodynamic Affinity. In this work, a framework is proposed to evaluate and predict polymer–solute Thermodynamic Affinity via the polymer-phase activity coefficient. RESULTS Polymer screening via Thermodynamic Affinity was shown to be most effective at very dilute concentrations, where partition coefficients can be estimated using infinite dilution activity coefficients. In the absence of published values, UNIFAC-vdW-FV or Flory–Huggins based activity models can provide very good predictions for the polymer-phase activity coefficient, significantly improving upon previous approaches using Hildebrand and Hansen solubility parameter differences. For non-dilute systems, however, the activity models failed to consider the full effects of concentration on partition coefficient. Additionally, a reduction in polymer molecular weight resulted in improved partition coefficients, a phenomena well described by the activity models. CONCLUSION Predicting and experimentally quantifying polymer–solute Thermodynamic Affinity at very dilute concentrations will aid future attempts at TPPB polymer selection. Furthermore, experimental partition coefficient data at a range of operational concentrations will indicate how TPPB effectiveness will change throughout the fermentation course. Finally, reduction of polymer molecular weight to improve solute partitioning should be investigated further for a range of polymers. © 2014 Society of Chemical Industry
-
A framework to predict and experimentally evaluate polymer–solute Thermodynamic Affinity for two‐phase partitioning bioreactor (TPPB) applications
Journal of Chemical Technology & Biotechnology, 2014Co-Authors: Stuart L Bacon, J. Scott Parent, Andrew J DaugulisAbstract:BACKGROUND Selection of a polymer for two-phase partitioning bioreactor (TPPB) applications has previously been limited to heuristic approaches. However, recent interest has focused on first principles' selection methods based on polymer crystallinity, glass transition temperature and polymer–solute Thermodynamic Affinity. In this work, a framework is proposed to evaluate and predict polymer–solute Thermodynamic Affinity via the polymer-phase activity coefficient. RESULTS Polymer screening via Thermodynamic Affinity was shown to be most effective at very dilute concentrations, where partition coefficients can be estimated using infinite dilution activity coefficients. In the absence of published values, UNIFAC-vdW-FV or Flory–Huggins based activity models can provide very good predictions for the polymer-phase activity coefficient, significantly improving upon previous approaches using Hildebrand and Hansen solubility parameter differences. For non-dilute systems, however, the activity models failed to consider the full effects of concentration on partition coefficient. Additionally, a reduction in polymer molecular weight resulted in improved partition coefficients, a phenomena well described by the activity models. CONCLUSION Predicting and experimentally quantifying polymer–solute Thermodynamic Affinity at very dilute concentrations will aid future attempts at TPPB polymer selection. Furthermore, experimental partition coefficient data at a range of operational concentrations will indicate how TPPB effectiveness will change throughout the fermentation course. Finally, reduction of polymer molecular weight to improve solute partitioning should be investigated further for a range of polymers. © 2014 Society of Chemical Industry
Anna S Antipova - One of the best experts on this subject based on the ideXlab platform.
-
Structural and Thermodynamic features of covalent conjugates of sodium caseinate with maltodextrins underlying their functionality.
Food & Function, 2011Co-Authors: N. V. Grigorovich, Maria G Semenova, Larisa E Belyakova, Anna S Antipova, D. V. Moiseenko, M. S. Anokhina, Yu. N. Polikarpov, N. Korica, B. A. BaranovAbstract:The sodium caseinate (SCN)–maltodextrin (MD) covalent conjugates were prepared by a food-grade process involving the first step of the Maillard reaction. The covalent conjugates were prepared with different weight ratios of biopolymers (RMD : SCN = 0.4; 1; 2; 5) in the system using maltodextrins of strongly different dextrose equivalents (DE), i.e., DE = 2 and 10. We have observed that the covalent conjugation of SCN with MD, in contrast to their simple mixing, improved the protein solubility in an aqueous medium in a wide pH range that was more pronounced in the vicinity of the SCN isoelectric point (pH 3.8–4.4). The extent of SCN solubility was mainly governed by the weight/molar ratio of the biopolymers in the covalent conjugates, RMD : SCN. Data of static multiangle laser light scattering showed that the revealed increase in the solubility of the conjugates could be predominantly attributable to the dramatic increase in their Thermodynamic Affinity for an aqueous medium. Which was most pronounced for the maltodextrin with the higher DE (DE = 10). The direct relationship between the increase in the solubility of the conjugates and the increase in their foaming ability, as compared against SCN, has been revealed as a rule both at neutral pH and at the pI. In addition, the found improvement in the protein foaming ability was also defined by both the weight/molar ratio (RMD : SCN) and the dextrose equivalent of the maltodextrins attached to the protein.
-
Analysis of light scattering data on the sodium caseinate assembly as a response to the interactions with likely charged anionic surfactant
Food Hydrocolloids, 2007Co-Authors: Maria G Semenova, Larisa E Belyakova, Anna S Antipova, Yu. N. Polikarpov, Ivana Stankovic, M. S. AnokhinaAbstract:We report on the modification of the parameters of sodium caseinate nanoparticles, measured basically by static and dynamic light scattering (the weight-average molar mass M w ; the radius of gyration R G , the hydrodynamic radius R h , their ratio (p = R G /R h ), reflecting the shape of the scattering particles; and the Thermodynamic Affinity for an aqueous medium (the second virial coefficient A 2 )), as a response to the interactions with the likely charged anionic surfactant-CITREM (the equimass mixtures of the esters of the stearic and palmitic acids with a citric acid) over a wide range of the surfactant low concentrations at pH 7.2. We found that the protein association, induced by the interactions with the likely charged anionic surfactant, was most pronounced at the medium value of the ionic strength under the ionic strength variation from 0.005 to 0.1 M, namely, at 0.05 M. The detailed dependence of the parameters of the surfactant-modified sodium caseinate on the CITREM concentration allowed recognizing the three concentration regions with the specific parameters of the complex (protein+surfactant) nanoparticles at the ionic strength that is peculiar to the most marked protein association (0.05 M). The first concentration region is at C CITREM
-
influence of maltodextrins with different dextrose equivalent on the Thermodynamic properties of legumin in a bulk and at the air water interface
Colloids and Surfaces B: Biointerfaces, 1999Co-Authors: Maria G Semenova, Larisa E Belyakova, Anna S Antipova, Maria A JubanovaAbstract:Abstract This paper presents the influence of the potato maltodextrins with different dextrose equivalent (DE 2, 6 and 10) on the legumin Thermodynamic properties in the bulk aqueous medium and at the air–water interface both in the simple mixed solutions and under the covalent complex (conjugate) formation (by the Maillard reaction), at pH 7.0 and ionic strength of 0.05 mol dm−3. The weak net attractive interaction between legumin and maltodextrin has been found in an aqueous medium by both the light scattering and the mixing calorimetry methods. On the basis of both the mixing and differential scanning calorimetry data a hydrogen bonding is supposed to be fundamental for this interaction. It was found that these attractive interactions produced an increase in the protein hydrophilicity and consequently a decrease in the protein surface activity. The effect was more pronounced for the maltodextrin with the largest dextrose equivalent (DE 10). The covalent complexation between legumin and maltodextrin induced the change of the fine hydrophobic–hydrophilic balance in the protein globule due to both addition of the hydrophilicity of the covalently attached polysaccharide and the partial protein unfolding as a result of the such kind of attachment. The combined data of tensiometry, light scattering, mixing and differential scanning calorimetry demonstrated the importance of the maltodextrin polymerization (DE) in controlling both the protein hydrophilicity (Thermodynamic Affinity for the aqueous phase) and surface activity.
-
Influence of maltodextrins with different dextrose equivalent on the Thermodynamic properties of legumin in a bulk and at the air–water interface
Colloids and Surfaces B: Biointerfaces, 1999Co-Authors: Maria G Semenova, Larisa E Belyakova, Anna S Antipova, Maria A JubanovaAbstract:Abstract This paper presents the influence of the potato maltodextrins with different dextrose equivalent (DE 2, 6 and 10) on the legumin Thermodynamic properties in the bulk aqueous medium and at the air–water interface both in the simple mixed solutions and under the covalent complex (conjugate) formation (by the Maillard reaction), at pH 7.0 and ionic strength of 0.05 mol dm−3. The weak net attractive interaction between legumin and maltodextrin has been found in an aqueous medium by both the light scattering and the mixing calorimetry methods. On the basis of both the mixing and differential scanning calorimetry data a hydrogen bonding is supposed to be fundamental for this interaction. It was found that these attractive interactions produced an increase in the protein hydrophilicity and consequently a decrease in the protein surface activity. The effect was more pronounced for the maltodextrin with the largest dextrose equivalent (DE 10). The covalent complexation between legumin and maltodextrin induced the change of the fine hydrophobic–hydrophilic balance in the protein globule due to both addition of the hydrophilicity of the covalently attached polysaccharide and the partial protein unfolding as a result of the such kind of attachment. The combined data of tensiometry, light scattering, mixing and differential scanning calorimetry demonstrated the importance of the maltodextrin polymerization (DE) in controlling both the protein hydrophilicity (Thermodynamic Affinity for the aqueous phase) and surface activity.