M. Salim, A. MacGibbon, C. Nowell, Andrew J. Clulow, B. Boyd
Interfacial compositions of fat globules modulate the digestion behaviour of milk triglycerides in the gastrointestinal tract, thereby affecting lipid metabolism and delivery of nutrients. In this study, we aim to understand the impact of emulsifiers on lipid digestibility and the self-assembled liquid crystal structures formed by anhydrous milk fat (AMF) during digestion. AMF was emulsified with casein and milk phospholipids, and digestion was performed in both gastric and small intestinal conditions to account for changes at the oil/water interface following enzymatic digestion in the gastric phase. Small angle X-ray scattering was used to characterise the self-assembled structures of the digestion products, while coherent anti-Stokes Raman scattering microscopy was utilised to probe changes in lipid distribution at the single droplet level during digestion. Our findings confirmed that emulsifiers play a key role in the digestion of AMF. Milk phospholipids exhibited a protective effect on milk triglycerides against pancreatic lipase digestion by slowing digestion, but this effect was slightly negated in emulsions pre-digested under gastric conditions. The overall types of liquid crystal structures formed after digestion of casein- and milk phospholipids-emulsified AMF were comparable to commercial bovine milk irrespective of gastric pre-treatment. However, emulsification of AMF with milk phospholipids resulted in changes in the microstructures of the liquid crystal phases, suggesting potential interactions between the digested products of the fat globules and milk phospholipids. This study highlights the importance of emulsifiers in regulating lipid digestion behaviour and lipid self-assembly during digestion.
{"title":"Influence of Casein and Milk Phospholipid Emulsifiers on the Digestion and Self-Assembled Structures of Milk Lipids","authors":"M. Salim, A. MacGibbon, C. Nowell, Andrew J. Clulow, B. Boyd","doi":"10.3390/colloids7030056","DOIUrl":"https://doi.org/10.3390/colloids7030056","url":null,"abstract":"Interfacial compositions of fat globules modulate the digestion behaviour of milk triglycerides in the gastrointestinal tract, thereby affecting lipid metabolism and delivery of nutrients. In this study, we aim to understand the impact of emulsifiers on lipid digestibility and the self-assembled liquid crystal structures formed by anhydrous milk fat (AMF) during digestion. AMF was emulsified with casein and milk phospholipids, and digestion was performed in both gastric and small intestinal conditions to account for changes at the oil/water interface following enzymatic digestion in the gastric phase. Small angle X-ray scattering was used to characterise the self-assembled structures of the digestion products, while coherent anti-Stokes Raman scattering microscopy was utilised to probe changes in lipid distribution at the single droplet level during digestion. Our findings confirmed that emulsifiers play a key role in the digestion of AMF. Milk phospholipids exhibited a protective effect on milk triglycerides against pancreatic lipase digestion by slowing digestion, but this effect was slightly negated in emulsions pre-digested under gastric conditions. The overall types of liquid crystal structures formed after digestion of casein- and milk phospholipids-emulsified AMF were comparable to commercial bovine milk irrespective of gastric pre-treatment. However, emulsification of AMF with milk phospholipids resulted in changes in the microstructures of the liquid crystal phases, suggesting potential interactions between the digested products of the fat globules and milk phospholipids. This study highlights the importance of emulsifiers in regulating lipid digestion behaviour and lipid self-assembly during digestion.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43099683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In many modern technologies, surface-active compounds, such as surfactants, polymers, proteins, particles and their mixtures, are essential components. They change the dynamic and equilibrium properties of the inherent interfaces, which is mostly visible in foams and emulsions. The interfacial dilational visco-elasticity is probably the most informative quantity due to its direct interrelation to the equation of state of the corresponding interfacial layers as well as the mechanisms governing the interfacial molecular dynamics. The scientific field of interfacial visco-elasticity, although quite young, has been inspired by the pioneering work of Marangoni, Levich, Lucassen, Lucassen-Reynders, Hansen, van den Tempel and Krotov, and during the last decades, also significantly by Boris Noskov. His contributions to the theoretical foundation and experimental analysis of polymer and mixed surfactant–polymer interfacial layers in particular are essential.
在许多现代技术中，表面活性化合物，如表面活性剂、聚合物、蛋白质、颗粒及其混合物，是必不可少的成分。它们改变了固有界面的动态和平衡特性，这在泡沫和乳液中最为明显。界面膨胀粘弹性可能是信息量最大的，因为它与相应界面层的状态方程以及控制界面分子动力学的机制直接相关。界面粘弹性的科学领域虽然很年轻，但受到了Marangoni、Levich、Lucassen、Lucassen-Reynders、Hansen、van den Tempel和Krotov的开创性工作的启发，在过去的几十年里，也受到了Boris Noskov的启发。他对聚合物和混合表面活性剂-聚合物界面层的理论基础和实验分析的贡献尤其重要。
{"title":"Characterization of Liquid Adsorption Layers Formed from Aqueous Polymer–Surfactant Solutions—Significant Contributions by Boris A. Noskov","authors":"O. Milyaeva, A. Bykov, Reinhard Miller","doi":"10.3390/colloids7030055","DOIUrl":"https://doi.org/10.3390/colloids7030055","url":null,"abstract":"In many modern technologies, surface-active compounds, such as surfactants, polymers, proteins, particles and their mixtures, are essential components. They change the dynamic and equilibrium properties of the inherent interfaces, which is mostly visible in foams and emulsions. The interfacial dilational visco-elasticity is probably the most informative quantity due to its direct interrelation to the equation of state of the corresponding interfacial layers as well as the mechanisms governing the interfacial molecular dynamics. The scientific field of interfacial visco-elasticity, although quite young, has been inspired by the pioneering work of Marangoni, Levich, Lucassen, Lucassen-Reynders, Hansen, van den Tempel and Krotov, and during the last decades, also significantly by Boris Noskov. His contributions to the theoretical foundation and experimental analysis of polymer and mixed surfactant–polymer interfacial layers in particular are essential.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44687742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elham Ommat Mohammadi, S. Yeganehzad, M. A. Hesarinejad, M. Dabestani, E. Schneck, Reinhard Miller
Vacuum cold plasma (VCP), a novel non-thermal processing technology used to modify the physicochemical properties and functionalities of food materials, was applied to whey protein isolate (WPI). The treatment affects the protein chemistry and, as a result, leads to differences in the behavior in solution and at interfaces. To minimize the undesirable effects of high oxidation and to increase the effectiveness of reactive species, the VCP treatment was applied at low pressure using different types of gases (air, combination of argon and air, and sulfur hexafluoride (SF6)). The treatment led to a decrease in the sulfur content and an increase in the carbonyl content, evidenced by oxidation reactions and enhanced disulfide bond formation, as well as cross-linking of protein molecules. Fluorescence-based indicators suggest that the hydrophobicity of the proteins as well as their aggregation increase after VCP treatment with an argon–air gas mixture; however, it decreases after VCP treatments with air and SF6. The chemical modifications further lead to changes in the pH of aqueous WPI solutions, as well as the average size and ζ-potential of WPI aggregates. Moreover, the dynamic surface tension, surface dilational elasticity, and the thickness of the WPI adsorption layers at the air/water interface depend on the VCP type. SF6 plasma treatment leads to a significant decrease in pH and an increase in the ζ-potential, and consequently to a significant increase in the aggregate size. The dynamic surface tension as well as the adsorption rates increase after SF6VCP treatment, but decrease after air–VCP and argon–air–VCP treatments. The adsorbed WPI aggregates form strong viscoelastic interfacial layers, the thickness of which depends on the type of VCP treatment.
{"title":"Effects of Various Types of Vacuum Cold Plasma Treatment on the Chemical and Functional Properties of Whey Protein Isolate with a Focus on Interfacial Properties","authors":"Elham Ommat Mohammadi, S. Yeganehzad, M. A. Hesarinejad, M. Dabestani, E. Schneck, Reinhard Miller","doi":"10.3390/colloids7030054","DOIUrl":"https://doi.org/10.3390/colloids7030054","url":null,"abstract":"Vacuum cold plasma (VCP), a novel non-thermal processing technology used to modify the physicochemical properties and functionalities of food materials, was applied to whey protein isolate (WPI). The treatment affects the protein chemistry and, as a result, leads to differences in the behavior in solution and at interfaces. To minimize the undesirable effects of high oxidation and to increase the effectiveness of reactive species, the VCP treatment was applied at low pressure using different types of gases (air, combination of argon and air, and sulfur hexafluoride (SF6)). The treatment led to a decrease in the sulfur content and an increase in the carbonyl content, evidenced by oxidation reactions and enhanced disulfide bond formation, as well as cross-linking of protein molecules. Fluorescence-based indicators suggest that the hydrophobicity of the proteins as well as their aggregation increase after VCP treatment with an argon–air gas mixture; however, it decreases after VCP treatments with air and SF6. The chemical modifications further lead to changes in the pH of aqueous WPI solutions, as well as the average size and ζ-potential of WPI aggregates. Moreover, the dynamic surface tension, surface dilational elasticity, and the thickness of the WPI adsorption layers at the air/water interface depend on the VCP type. SF6 plasma treatment leads to a significant decrease in pH and an increase in the ζ-potential, and consequently to a significant increase in the aggregate size. The dynamic surface tension as well as the adsorption rates increase after SF6VCP treatment, but decrease after air–VCP and argon–air–VCP treatments. The adsorbed WPI aggregates form strong viscoelastic interfacial layers, the thickness of which depends on the type of VCP treatment.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45292801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents a mathematical model of drop size distribution during dropwise condensation on a superhydrophobic surface. The model is developed by combining a power law growth model, an exponentially decaying population model, and a Gaussian probability model for growth variations. The model is validated against experiment data, with correlations ranging from 88% to 94%. The growth model is shown to sufficiently describe the growth of drops from 0.02 mm to 0.1 mm but may be extrapolated to describe the growth of even smaller drops. The experiment data show that drop size distribution or frequency distribution of drops of different sizes varies significantly with time and may be considered pseudo-cyclic. The developed model, together with the sweep rate of drops, sufficiently describes this behavior and, consequently, may also be used to better estimate the heat transfer rate due to dropwise condensation.
{"title":"Development of Drop Size Distribution Model for Dropwise Condensation on a Superhydrophobic Surface","authors":"G. Denoga, J. Balbarona, Hernando S. Salapare","doi":"10.3390/colloids7030053","DOIUrl":"https://doi.org/10.3390/colloids7030053","url":null,"abstract":"This study presents a mathematical model of drop size distribution during dropwise condensation on a superhydrophobic surface. The model is developed by combining a power law growth model, an exponentially decaying population model, and a Gaussian probability model for growth variations. The model is validated against experiment data, with correlations ranging from 88% to 94%. The growth model is shown to sufficiently describe the growth of drops from 0.02 mm to 0.1 mm but may be extrapolated to describe the growth of even smaller drops. The experiment data show that drop size distribution or frequency distribution of drops of different sizes varies significantly with time and may be considered pseudo-cyclic. The developed model, together with the sweep rate of drops, sufficiently describes this behavior and, consequently, may also be used to better estimate the heat transfer rate due to dropwise condensation.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44565212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rheology of suspensions of solid particles in aqueous matrix liquids thickened by starch nanoparticles (SNP) was investigated. The SNP concentration varied from 9.89 to 34.60 wt% based on the aqueous matrix phase. The solids concentration of suspensions varied from 0 to 47 wt% (0 to 56 vol%). The suspensions at any given SNP concentration were generally Newtonian at low solids concentrations. At high solids concentrations, the suspensions were non-Newtonian shear-thinning. With the increase in the SNP concentration, the suspensions become non-Newtonian at a lower solids concentration. The rheological behavior of non-Newtonian suspensions could be described adequately with a power-law model. The consistency index of the suspension increased with the increase in solids concentration of the suspension at any given SNP concentration. The flow behavior index of suspensions was well below unity at high solids concentrations, indicating non-Newtonian shear-thinning behavior. The value of the flow behavior index decreased with the increase in solids concentration indicating an enhancement of shear-thinning in suspensions. The experimental viscosity and consistency data for Newtonian and non-Newtonian suspensions showed good agreement with the predictions of the Pal viscosity model for suspensions.
{"title":"Rheology of Suspensions of Solid Particles in Liquids Thickened by Starch Nanoparticles","authors":"Ghazaleh Ghanaatpishehsanaei, R. Pal","doi":"10.3390/colloids7030052","DOIUrl":"https://doi.org/10.3390/colloids7030052","url":null,"abstract":"The rheology of suspensions of solid particles in aqueous matrix liquids thickened by starch nanoparticles (SNP) was investigated. The SNP concentration varied from 9.89 to 34.60 wt% based on the aqueous matrix phase. The solids concentration of suspensions varied from 0 to 47 wt% (0 to 56 vol%). The suspensions at any given SNP concentration were generally Newtonian at low solids concentrations. At high solids concentrations, the suspensions were non-Newtonian shear-thinning. With the increase in the SNP concentration, the suspensions become non-Newtonian at a lower solids concentration. The rheological behavior of non-Newtonian suspensions could be described adequately with a power-law model. The consistency index of the suspension increased with the increase in solids concentration of the suspension at any given SNP concentration. The flow behavior index of suspensions was well below unity at high solids concentrations, indicating non-Newtonian shear-thinning behavior. The value of the flow behavior index decreased with the increase in solids concentration indicating an enhancement of shear-thinning in suspensions. The experimental viscosity and consistency data for Newtonian and non-Newtonian suspensions showed good agreement with the predictions of the Pal viscosity model for suspensions.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45192570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The binding of drugs to nucleic acids, proteins, lipids, amino acids, and other biological receptors is necessary for the transportation of drugs. However, various side effects may also originate if the bound drug molecules are not dissociated from the carrier, especially with the aid of non-toxic agents. The sequestration of small drug molecules bound to biomolecules is thus central to counter issues related to drug overdose and drug detoxification. In this article, we aim to present several methods used for the dissociation of small drug molecules bound to different biological and biomimicking assemblies under in vitro experimental conditions. To this effect, the application of various molecular assemblies, like micelles, mixed micelles, molecular containers, like β-cyclodextrin, cucurbit[7]uril hydrate, etc., has been discussed. Herein, we also try to shed light on the driving forces underlying such sequestration processes through spectroscopic and calorimetric techniques.
{"title":"Sequestration of Drugs from Biomolecular and Biomimicking Environments: Spectroscopic and Calorimetric Studies","authors":"Rahul Yadav, Bijan Kumar Paul, S. Mukherjee","doi":"10.3390/colloids7030051","DOIUrl":"https://doi.org/10.3390/colloids7030051","url":null,"abstract":"The binding of drugs to nucleic acids, proteins, lipids, amino acids, and other biological receptors is necessary for the transportation of drugs. However, various side effects may also originate if the bound drug molecules are not dissociated from the carrier, especially with the aid of non-toxic agents. The sequestration of small drug molecules bound to biomolecules is thus central to counter issues related to drug overdose and drug detoxification. In this article, we aim to present several methods used for the dissociation of small drug molecules bound to different biological and biomimicking assemblies under in vitro experimental conditions. To this effect, the application of various molecular assemblies, like micelles, mixed micelles, molecular containers, like β-cyclodextrin, cucurbit[7]uril hydrate, etc., has been discussed. Herein, we also try to shed light on the driving forces underlying such sequestration processes through spectroscopic and calorimetric techniques.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44120426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Giselle Vite, Samuel Lopez-Godoy, P. Díaz-Leyva, A. Kozina
The optimization of fabrication conditions for colloidal micron-sized oblates obtained by the deformation of an oil-in-hydrogel emulsion is reported. The influence of the type of emulsion stabilizer, ultrasonication parameters, and emulsion and gel mixing conditions was explored. The best conditions with which to obtain more uniform particles were using polyvinyl alcohol as an emulsion stabilizer mixed with the gelatine solution at 35 °C and slowly cooling to room temperature. Four fractionation methods were applied to oblates to improve their size uniformity. The iterative differential centrifugation method produced the best size polydispersity reduction.
{"title":"Improving the Size Distribution of Polymeric Oblates Fabricated by the Emulsion-in-Gel Deformation Method","authors":"Giselle Vite, Samuel Lopez-Godoy, P. Díaz-Leyva, A. Kozina","doi":"10.3390/colloids7030050","DOIUrl":"https://doi.org/10.3390/colloids7030050","url":null,"abstract":"The optimization of fabrication conditions for colloidal micron-sized oblates obtained by the deformation of an oil-in-hydrogel emulsion is reported. The influence of the type of emulsion stabilizer, ultrasonication parameters, and emulsion and gel mixing conditions was explored. The best conditions with which to obtain more uniform particles were using polyvinyl alcohol as an emulsion stabilizer mixed with the gelatine solution at 35 °C and slowly cooling to room temperature. Four fractionation methods were applied to oblates to improve their size uniformity. The iterative differential centrifugation method produced the best size polydispersity reduction.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48668404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Riquelme, Constanza Savignones, A. Lopez, R. Zúñiga, C. Arancibia
Senior populations may experience nutritional deficiencies due to physiological changes that occur during aging, such as swallowing disorders, where easy-to-swallow foods are required to increase comfort during food consumption. In this context, the design of nanoemulsion-based gels (NBGs) can be an alternative for satisfying the textural requirements of seniors. This article aimed to develop NBGs with different gelling agents, evaluating their physical properties. NBGs were prepared with a base nanoemulsion (d = 188 nm) and carrageenan (CA) or agar (AG) at two concentrations (0.5–1.5% w/w). The color, rheology, texture, water-holding capacity (WHC) and FT-IR spectra were determined. The results showed that the CA-based gels were more yellow than the AG ones, with the highest hydrocolloid concentration. All gels showed a non-Newtonian flow behavior, where the gels’ consistency and shear-thinning behavior increased with the hydrocolloid concentration. Furthermore, elastic behavior predominated over viscous behavior in all the gels, being more pronounced in those with AG. Similarly, all the gels presented low values of textural parameters, indicating an adequate texture for seniors. The FT-IR spectra revealed non-covalent interactions between nanoemulsions and hydrocolloids, independent of their type and concentration. Finally, the CA-based gels presented a higher WHC than the AG ones. Therefore, NBG physical properties can be modulated according to gelling agent type in order to design foods adapted for seniors.
{"title":"Effect of Gelling Agent Type on the Physical Properties of Nanoemulsion-Based Gels","authors":"N. Riquelme, Constanza Savignones, A. Lopez, R. Zúñiga, C. Arancibia","doi":"10.3390/colloids7030049","DOIUrl":"https://doi.org/10.3390/colloids7030049","url":null,"abstract":"Senior populations may experience nutritional deficiencies due to physiological changes that occur during aging, such as swallowing disorders, where easy-to-swallow foods are required to increase comfort during food consumption. In this context, the design of nanoemulsion-based gels (NBGs) can be an alternative for satisfying the textural requirements of seniors. This article aimed to develop NBGs with different gelling agents, evaluating their physical properties. NBGs were prepared with a base nanoemulsion (d = 188 nm) and carrageenan (CA) or agar (AG) at two concentrations (0.5–1.5% w/w). The color, rheology, texture, water-holding capacity (WHC) and FT-IR spectra were determined. The results showed that the CA-based gels were more yellow than the AG ones, with the highest hydrocolloid concentration. All gels showed a non-Newtonian flow behavior, where the gels’ consistency and shear-thinning behavior increased with the hydrocolloid concentration. Furthermore, elastic behavior predominated over viscous behavior in all the gels, being more pronounced in those with AG. Similarly, all the gels presented low values of textural parameters, indicating an adequate texture for seniors. The FT-IR spectra revealed non-covalent interactions between nanoemulsions and hydrocolloids, independent of their type and concentration. Finally, the CA-based gels presented a higher WHC than the AG ones. Therefore, NBG physical properties can be modulated according to gelling agent type in order to design foods adapted for seniors.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42750713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, alginate-chitosan microgel particles were formed at different pH levels with the aim of using them as viscoelastic interfacial layers, which confer emulsion stability to food systems. The particles’ size and structural characteristics were determined using laser diffraction, confocal laser microscopy (CLSM), and time-domain nuclear magnetic resonance (TD-NMR). The pH affected the microgel characteristics, with larger particles formed at lower pH levels. T2 relaxation measurements with TD-NMR did not reveal differences in the mobility within the particles for the different pH levels, which could have been related to the more or less swollen structure. The rate of adsorption of the particles at the sunflower oil–water interface differed between particles formed at different pH levels, but the equilibrium interfacial tension of all systems was similar. Higher interfacial dilatational viscoelasticity was obtained for the systems at lower pH (3, 4, 5), with G’ reaching 13.6 mN/m (0.1 Hz) at pH 3. The interfacial rheological regime transitioned from a linear elastic regime at lower pH to a linear but more viscoelastic one at higher pH. The thicker, highly elastic interfacial layer at low pH, in combination with the higher charges expected at lower pH, was related to its performance during emulsification and the performance of the emulsion during storage. As revealed by laser diffraction and CLSM, the droplet sizes of emulsions formed at pH 6 and 7 were significantly larger and increased in size during 1 week of storage. CLSM examination of the emulsions revealed bridging flocculation with the higher pH. Nevertheless, all emulsions formed with microgel systems presented macroscopic volumetric stability for periods exceeding 1 week at 25 °C. A potential application of the present systems could be in the formation of stable, low-fat dressings without the addition of any emulsifier, allowing, at the same time, the release of the bioactive compounds for which such particles are known.
{"title":"Alginate-Chitosan Microgel Particles, Water–Oil Interfacial Layers, and Emulsion Stabilization","authors":"Aggelos Charisis, E. Kalogianni","doi":"10.3390/colloids7020048","DOIUrl":"https://doi.org/10.3390/colloids7020048","url":null,"abstract":"In this work, alginate-chitosan microgel particles were formed at different pH levels with the aim of using them as viscoelastic interfacial layers, which confer emulsion stability to food systems. The particles’ size and structural characteristics were determined using laser diffraction, confocal laser microscopy (CLSM), and time-domain nuclear magnetic resonance (TD-NMR). The pH affected the microgel characteristics, with larger particles formed at lower pH levels. T2 relaxation measurements with TD-NMR did not reveal differences in the mobility within the particles for the different pH levels, which could have been related to the more or less swollen structure. The rate of adsorption of the particles at the sunflower oil–water interface differed between particles formed at different pH levels, but the equilibrium interfacial tension of all systems was similar. Higher interfacial dilatational viscoelasticity was obtained for the systems at lower pH (3, 4, 5), with G’ reaching 13.6 mN/m (0.1 Hz) at pH 3. The interfacial rheological regime transitioned from a linear elastic regime at lower pH to a linear but more viscoelastic one at higher pH. The thicker, highly elastic interfacial layer at low pH, in combination with the higher charges expected at lower pH, was related to its performance during emulsification and the performance of the emulsion during storage. As revealed by laser diffraction and CLSM, the droplet sizes of emulsions formed at pH 6 and 7 were significantly larger and increased in size during 1 week of storage. CLSM examination of the emulsions revealed bridging flocculation with the higher pH. Nevertheless, all emulsions formed with microgel systems presented macroscopic volumetric stability for periods exceeding 1 week at 25 °C. A potential application of the present systems could be in the formation of stable, low-fat dressings without the addition of any emulsifier, allowing, at the same time, the release of the bioactive compounds for which such particles are known.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47995607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hashem Ahmadi Tighchi, M. H. Kayhani, A. Faezian, S. Yeganehzad, Reinhard Miller
The root of the licorice plant (Glycyrrhiza glabra) is rich in natural surfactants, called saponins. The beneficial properties of this plant have led to different applications, including its use as a foaming agent. In this research, a theoretical model and its validity are discussed for the liquid drainage of foams made from licorice root extract solutions. After stating the important characteristics in the free drainage of foam, a relationship of the drained liquid volume based on effective parameters was obtained via a simplification of the governing equation. The theoretical model is applied to experimental foam drainage data measured at different concentrations of licorice root extract solutions. A comparison of theoretical and experimental results shows good agreement for the volume of drained liquid as a function of time. The characteristics obtained from the combination of effective parameters allows for a quantification of the drainage rate. In addition, the drainage rate at the beginning of the foam decay process, as a measure of stability, can be estimated using measurable properties.
{"title":"Examination of a Theoretical Model for Drainage of Foams Prepared from Licorice Root Extract Solution","authors":"Hashem Ahmadi Tighchi, M. H. Kayhani, A. Faezian, S. Yeganehzad, Reinhard Miller","doi":"10.3390/colloids7020047","DOIUrl":"https://doi.org/10.3390/colloids7020047","url":null,"abstract":"The root of the licorice plant (Glycyrrhiza glabra) is rich in natural surfactants, called saponins. The beneficial properties of this plant have led to different applications, including its use as a foaming agent. In this research, a theoretical model and its validity are discussed for the liquid drainage of foams made from licorice root extract solutions. After stating the important characteristics in the free drainage of foam, a relationship of the drained liquid volume based on effective parameters was obtained via a simplification of the governing equation. The theoretical model is applied to experimental foam drainage data measured at different concentrations of licorice root extract solutions. A comparison of theoretical and experimental results shows good agreement for the volume of drained liquid as a function of time. The characteristics obtained from the combination of effective parameters allows for a quantification of the drainage rate. In addition, the drainage rate at the beginning of the foam decay process, as a measure of stability, can be estimated using measurable properties.","PeriodicalId":10433,"journal":{"name":"Colloids and Interfaces","volume":"33 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41307943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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