Coalescence Degree Research Articles

Double (W1/O/W2) emulsions prepared with natural vegetable oils and varied inner glucose concentration: Microstructure, rheology and stability

The objective was to study the microstructure, rheology and stability of double (W1/O/W2) emulsions prepared with Tween 80 as hydrophilic emulsifier and coconut, palm or sunflower oil. The effects of glucose concentration in inner aqueous phase and crystallization of lipid phase were analyzed. Aggregation of oil globules by partial coalescence was observed in emulsions prepared with coconut or palm oil because of the crystallization of the lipid phase. The increase of glucose concentration increased the amount of inner water by osmotic swelling and produced a higher partial coalescence degree due to a higher collision frequency between oil globules. Consequently, higher elastic and viscous modules were observed at higher glucose concentration. Fat crystals in lipid phase allowed a partial retention of inner water in the absence of glucose, but they also favored the release of inner water due to partial coalescence. Creaming stability was enhanced by the presence of glucose, because of the formation of a three-dimensional network of aggregated oil globules in emulsions with coconut or palm oil, and a higher packing and global density of oil globules in systems with sunflower oil. The obtained results contribute to the understanding of partial coalescence in W1/O/W2 emulsions, including its effects on inner water release and creaming stability. This work could be relevant for the design and stabilization of vegetable, lipid-reduced food emulsions prepared with natural oils.

Monoglyceride‐based oleogel and oleofoam as the fat substitute in fat‐reduced ice creams: The relation between partial coalescence degree and quality characteristics

Nowadays, consumers are interested in low‐fat ice creams. The potential of monoglyceride‐based oleogel and oleofoam as fat replacers in ice cream production was explored. Ice cream with 50% oleogel possessed appropriate partial coalescence degree (PCD, 44.17%), complete network structure endowed ideal qualities and the generation of perceived creaminess. Increasing oleogel substitution level (100%) resulted in a higher PCD (60.20%), a decreased overrun (35.43%), and a decline in quality due to larger ice crystal formation. Fifty per cent oleofoam promoted higher viscosity and structural strength of ice cream mix, but excessive coalescence (72.83%) caused the formation of large fat aggregates in ice cream.

Fat coalescence and texture improvement of ice cream based on medium-chain triglyceride oleogel: Effect of gelator type

Academics and industry have invested in creating novel and functional ice creams to meet the growing demand for frozen foods that promote human health and nutrition. This study aimed to investigate the effect of medium-chain triglyceride (MCT) oleogels that prepared by three different gelators on the development of ice creams, as a complete substitute for hydrogenated palm kernel oil (HPKO). The results showed that both beeswax (BW) and phytosterol-oryzanol (PS-GO) caused the fat crystal to grow into three-dimensional spherulites, while ethylcellulose (EC) inhibited crystal size growth. Among the three types of oleogel-based ice creams, the BW sample exhibited the highest coalescence degree, followed by PS-GO and EC. The difference was due to variations in crystal growth and rigid crystal strength. Both BW and PS-GO oleogels improved the firmness of the ice creams by enhancing the formation of crystal network structures in the emulsions. The EC oleogel did not contribute to the overrun of the ice cream. The well-structured fat with partially coalesced aggregates can stabilize the bubbles and hold the aqueous phase of ice creams, preventing the outflow during meltdown. Oleogels that form crystal networks can be employed as a preferable replacement for HPKO in the production of ice cream with superior texture.

Pickering emulsion with high freeze-thaw stability stabilized by xanthan gum/lysozyme nanoparticles and konjac glucomannan

In this study, freeze-thaw cycle experiments were conducted on food-grade Pickering emulsions co-stabilized with konjac glucomannan (KGM) and xanthan gum/lysozyme nanoparticles (XG/Ly NPs). The rheological properties, particle size, flocculation degree (FD), coalescence degree (CD), centrifugal stability, Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and microstructure of Pickering emulsion stabilized by KGM before and after freeze-thaw were characterized. It was found that as the concentration of KGM increased, the flocculation degree (FD) and coalescence degree (CD) of the emulsion decreased after the freeze-thaw cycle compared to the control sample, and the microscopic images showed that the droplets became smaller and less affected by the freeze-thaw cycles. The rheological and water-holding properties also confirmed that the KGM-added emulsions still had a strong gel network structure and prevented the separation of the continuous and dispersed phases of the droplets after freezing and thawing. Freeze-thaw treatments had a negative effect on the stable emulsion of XG/Ly NPs, while the addition of KGM improved the freeze-thaw stability of the emulsion, which provided a theoretical basis for the development of emulsion products with high freeze-thaw stability.

Reversibility of freeze-thaw/re-emulsification on Pickering emulsion stabilized with gliadin/sodium caseinate nanoparticles and konjac glucomannan

The reversibility of freeze-thaw/re-emulsification of Pickering emulsion stabilized by gliadin/sodium caseinate nanoparticles (Gli/CAS NPs) was improved by adding konjac glucomannan (KGM). With the increase in the KGM concentration, the delamination of emulsions after freeze-thaw treatment was significantly improved. The microstructure showed that the presence of KGM helped to maintain the network structure of continuous phases. In particular, the particle size of the emulsion did not increase significantly after three freeze-thaw cycles when the KGM concentration was 0.6 % and the oil phase fraction was 60 %. The results of flocculation degree and coalescence degree also indicated that KGM promoted the cross-linking between particles on the surface of the droplet and increased the thickness of the interfacial film of the droplet. Rheological analysis also proved the same result: the elastic modulus of the emulsion was still larger than the viscous modulus, which showed the ideal freeze thaw reversibility. After adding KGM, the emulsion formed a strong network structure with good stability for long-term storage and reversibility for freeze-thaw cycling/re-emulsification. Thus, the emulsion has broad application prospects in food, cosmetics, and pharmaceutical fields.

Value of CT spectral imaging in the differential diagnosis of sarcoidosis and Hodgkin's lymphoma based on mediastinal enlarged lymph node: A STARD compliant article.

To investigate the imaging characteristics of sarcoidosis and Hodgkin's lymphoma based on mediastinal enlarged lymph node using spectral CT and evaluate whether the quantitative information can improve the differential diagnosis of these diseases. This retrospective study was approved by the institutional review board, and written informed consent was obtained from all patients. Overall, 21 patients with sarcoidosis and 39 patients with Hodgkin's lymphoma were examined with CT spectral imaging during the arterial phase (AP) and venous phase (VP). The CT values on 40 to 140 keV monochromatic images and iodine (water) concentrations of enlarged lymph nodes were obtained in AP and VP. Iodine concentrations (ICs) were normalized to the iodine concentration in the aorta. The differences in normalized iodine concentrations (NICs) and hounsfield units (HU) curve slop (λHU) were calculated. Anatomical distribution of mediastinal lymph nodes and morphologic features were also compared. Receiver operating characteristic curves were generated to help establish threshold values for the parameters required for the significant differentiation of sarcoidosis from lymphomas. The CT values on 40 to 100 keV monochromatic images in AP and 40 to 50 keV in VP were higher in sarcoidosis than those in Hodgkin's lymphoma, the differences were statistically significant (P < .05); NICs during the AP and λHU during the AP (VP) in patients with sarcoidosis differed significantly from those in patients with Hodgkin's lymphoma. Receiver operating characteristic curves analysis showed that the monochromatic CT value on 40 keV in AP had the highest sensitivity (71.4%) and specificity (100%) in differentiating sarcoidosis from Hodgkin's lymphoma. The anatomic distribution, coalescence, calcification, compression, enhancement pattern and enhancement degree of the mediastinal enlarged lymph node differed significantly between the groups (P < .05). The combination of monochromatic CT value, NICs and λHU had higher sensitivity and specificity than did those of conventional qualitative CT image analysis during the combined phases. CT spectral imaging has promising potential for the diagnostic differentiation of Hodgkin's lymphomas and sarcoidosis. The monochromatic CT value, iodine content and λHU could be valuable parameters for differentiating Hodgkin's lymphomas and sarcoidosis based on mediastinal enlarged lymph node.

Hydrological connectivity promotes coalescence of bacterial communities in a floodplain.

Floodplains play essential roles in the ecological functions of regional environments. The merging and coalescence of bacterial communities in aquatic environments results in periodic patterns driven by regular hydrological activities, which may, in turn, influence ecological activities. However, the degree of bacterial community coalescence in the lateral and vertical directions as well as the underlying hydrological mechanism of floodplain ecosystems is poorly understood. Therefore, we investigated the spatiotemporal patterns and coalescence processes of planktonic and sedimentary bacterial communities during normal and high-water periods in a floodplain ecosystem of the Yellow River source region. We classified bacterial operational taxonomic units (OTUs) based on 16S rRNA gene sequencing, and quantified community coalescence by calculating the proportions of overlapping OTUs, the contributions of upstream sources to downstream sinks, and positive/negative cohesion. The results revealed major differences in the composition and diversity of planktonic and sedimentary bacterial communities. Bacterial community diversity in the high-water period was higher than in the normal period. Laterally, hydrological connectivity promoted the immigration and coalescence of bacterial communities to oxbow lakes in both the mainstream and tributaries, with the coalescence degree of planktonic bacteria (2.9%) higher than that of sedimentary bacteria (1.7%). Vertically, the coalescence degree of mainstream planktonic and sedimentary bacterial communities was highest, reaching 2.9%. Co-occurrence network analysis revealed that hydrological connectivity increased the complexity of the bacterial network and enhanced the coalescence of keystone species to oxbow lakes. Furthermore, community coalescence improved the competitiveness and dispersal of bacterial communities. This study demonstrated that coalescence of bacterial communities is driven by hydrological connectivity in a floodplain ecosystem. Further studies should investigate the processes of bacterial community coalescence in floodplains in more detail, which could provide new approaches for environmental protection and ecological function preservation.

Thickness-dependent physical and nanomechanical properties of [formula omitted] thin films

A set of undoped AlxGa1−xN epilayers with different thicknesses were grown on (0001) sapphire substrates using metal-organic chemical vapor deposition (MOCVD) technique, using the same gas-phase composition of trimethylaluminum (TMAl) and trimethylgallium (TMGa). Giving that the first growth stage is crucial for the successful fabrication of AlxGa1-xN epilayers; thus, SiN nano-mask, as an alternative method to nanoimprint lithography (NIL) which is used for patterning substrates, was deposited on sapphire substrate. Indeed, SiN treatment initiates the three-dimensional (3D) growth mode to efficiently decrease the threading dislocation density. It was found that depending on the film surface coalescence degree, the physical and nanomechanical properties are thoroughly dependent. As the non-coalescent surface is present, the porosity effects are dominant. As soon as the film thickness attains the surface coalescence, the Al incorporation is enhanced and convoyed with it point defects. Despite the decrease of the threading dislocations along with the film thickness evolution, it was observed that the physical properties are slightly decreased and the nanomechanical properties are improved. This is likely related to point defect interaction with nucleated dislocations. Moreover, the defects did not severally affect the plastic deformation capacity (ductility) of AlxGa1-xN films, where high indentation force was applied and no failure was revealed. Therefore, the balance between AlxGa1−xN physical and nanomechanical performances devotes to manufacture a wider range of efficient UV devices.

Effects of Glucose and Corn Syrup on the Physical Characteristics and Whipping Properties of Vegetable-Fat Based Whipped Creams.

The aim of this work is to evaluate the effects of glucose and corn syrup on the physical characteristics and whipping properties of whipped creams. The interfacial protein concentration and apparent viscosity of emulsions increased with an increasing sugar concentration. In whipped creams, a shorter optimum whipping time (top), higher fat coalescence degree, higher firmness and higher stability were detected as sugar concentration increased. The partial coalescence degree, overrun and firmness of whipped cream with 30 wt% glucose reached 76.49%, 306% and 3.82 N, respectively, significantly (p < 0.05) higher than those (67.15%, 235% and 3.19 N) with 30 wt% corn syrup. Compared with glucose at the same sugar concentration, higher interfacial protein concentration and less-shaped aggregates and coalescences were observed for the emulsions upon the addition of corn syrup, which caused a lower degree of fat coalescence and a lower firmness of whipped cream. The differences could be explained by the presence of maltodextrin (MDX) in corn syrup, which protects absorbed protein throughout freezing and retards the formation of a continuous network during whipping. As a result, the addition of sugars could well improve stability of emulsion, firmness and foam stability of whipped cream efficiently. With a 25–30 wt% sugar addition, even if there was a lower partial coalescence degree and firmness compared with glucose, whipped cream with corn syrup exhibited relatively good stability. These results suggest that MDX improves the stability of emulsion and, thus, has a potential use in low-sugar whipped cream.

Role of void shape on shock responses of nanoporous metallic glasses via molecular dynamics simulation

The void shape significantly affects the mechanical properties of nanoporous metallic glasses (NPMGs) under conventional loading. However, how the shock responses of NPMGs depend on the void shape has been rarely studied. In this work, shock simulations of Cu50Zr50 NPMGs containing voids with different shapes are performed by molecular dynamics, aiming to investigate the roles of the void shape on plastic deformation, void collapse, and spallation. The results reveal that the void shape has a significant effect on the peak value of the atomic strain curve and the fraction of atoms participating in the plastic deformation. There is a very weak dependence of the void collapse mode on the void shape under the weak shocks, where the voids collapse perpendicularly to the shock direction. As the shock strength increases, the void collapse mechanism gradually transforms into an internal jet, and the void shape plays an important role in the jet formation. During spallation, the initial damages tend to concentrate in the void collapse regions and then coalesce into large damages. The void shape influences the coalescence degree of spall damage. The spall strength is positively correlated with strain rate and local five-fold symmetry, but negatively correlated with temperature on the spall plane. Additionally, the void influences the spall strength due to the different distribution of the above factors after voids collapse in nanoporous samples.

Double (W1/O/W2) and Simple (O/W2) Emulsions Prepared with Soybean Flour Dispersion and Vegetable Fat: Partial Coalescence Promotion by Polyglycerol Polyricinoleate and Calcium

AbstractThe objective is to study the partial coalescence process in calcium‐fortified double (W1/O/W2) and simple (O/W2) emulsions prepared with soybean flour dispersion as continuous aqueous (W2) phase and vegetable fat plus polyglycerol polyricinoleate (PGPR) as lipophilic emulsifier (at varied concentration) in lipid phase. Calcium chloride is included in the dispersed aqueous (W1) phase and the W2 phase of W1/O/W2 and O/W2 emulsions, respectively. No partial coalescence is observed in the O/W2 emulsion without PGPR and calcium, while the inclusion of the emulsifier and/or divalent cation promotes the phenomenon. The presence of PGPR in lipid phase or calcium in W2 phase can enhance capture efficiency because of the decrease of electrostatic and steric repulsions between fat globules, the modification of fat crystals, and/or the increased size of individual globules. W1/O/W2 emulsions show a lower partial coalescence degree in comparison to O/W2 emulsions prepared with the same components, attributed to the isolation of a fraction of added calcium in the W1 phase of the former systems. PGPR produces microstructural and rheological changes over time in emulsions subjected to prolonged cold storage; but its effect is reduced in the presence of calcium, probably because of the formation of stronger globule aggregates.Practical applications: This article deals with two parallel phenomena occurring in W1/O/W2 and O/W2 emulsions prepared with soybean flour dispersion as W2 phase and vegetable fat in lipid phase: the promotion of partial coalescence by the lipophilic emulsifier, PGPR; and the aggregation of proteins and fat globules due to the presence of calcium in W2 phase. In this way, the effects of PGPR and/or calcium on partial coalescence are studied in these systems, analyzing their microstructure and rheology. The encapsulation of calcium within the W1 phase of W1/O/W2 emulsions and its impact on partial coalescence is also analyzed. The results obtained in this work can be relevant for the formulation of calcium‐fortified, vegetable food emulsions, showing a texture similar to whipped dairy cream, where PGPR concentration or calcium release can be controlled to adjust the rheological characteristics of the system.

The effect of salt ion on the freeze-thaw stability and digestibility of the lipophilic protein-hydroxypropyl methylcellulose emulsion

The effect of salt ion on the freeze-thaw stability of protein-polysaccharide emulsions remains controversial. In this study, we investigated the effects of two salts, CaCl2 and NaCl, on the freeze-thaw stability and digestion characteristics of soybean lipoprotein-hydroxypropyl methyl cellulose (LP-HPMC) emulsions. Analysis of the particle size, protein adsorption, and ζ-potential showed that addition of salt ions led to an increased extent of interfacial protein adsorption. The best oxidation stability and emulsification were observed when 100 mM salt was added. Analyses of the microstructure, creaming index, oiling off, and coalescence degree revealed that the presence of salt ions significantly improved the freeze-thaw stability of the emulsion, and addition of monovalent ions of NaCl to the emulsion to showed better interface protein crack resistance performance during the freeze-thaw cycle, low oiling off (8.75 ± 0.5 %), and coalescence degree (43.67 ± 2.5 %) compared to adding divalent ions of CaCl2. Moreover, Fourier infrared spectroscopy data revealed that the α-helix content in the secondary structure of LP was closely related to the freeze-thaw stability of the emulsion. Addition of salt ions delayed the release rate of internal oils in the LP-HPMC emulsion. These results provide a foundation of producing new emulsified foods with favorable freeze-thaw stability.

Experimental Research on Permeability of Coal and Rock Mass considering Postpeak Failure

In most mining areas of China, coal seams are characterized by low gas pressure, poor permeability, and high gas adsorption capacity, all of which have brought considerable difficulties to coal seam mining and coalbed methane (CBM) extraction. According to the multiyear scientific research and production practice of China, gas is migrated in quantity only after the coal body is directly mined, and the surrounding rocks deform and fracture under the mining influence. Thus, the key to effective control of gas migration and the coal and CBM comining technology lies in investigating the gas resolution, permeation, migration, and accumulation laws in the coal seams under the unloading confining pressure during mining. The MTS815.02 rock mechanics testing system and its supporting equipment are combined to test the permeability characteristics of coal and rock mass (postpeak fractured coal and sandstone specimens) under the loading and unloading of confining pressure using the steady method, and then, the permeation laws of the fractured coal and rock mass are obtained. Results show that after the postpeak rock crack propagation reaches a stable state, the confining pressure gradually increases, and the gas permeability presents an approximately linear reduction; in the postpeak unloading phase, the opening and coalescence degree of rock cracks gradually increase as the deformation extends. Thus, permeability reaches a peak value. The strain softening phase follows, where the cracks are closed and permeability declines to a certain extent. Moreover, the unloading step size of confining pressure has bearing on gas permeability. Specifically, as the unloading step size of confining pressure decreases, the change of gas permeability increases in stability.

Interfacial compositions of fat globules modulate coconut oil crystallization behavior and stability of whipped-frozen emulsions

Interfacial compositions and fat crystals are of importance for determining the partially crystalline fat globule stability. The objective of this work was to investigate the effects of different whey-to-milk protein ratios and sucrose fatty acid ester (SE) addition on the coconut oil crystallization behavior and whipped-frozen emulsion stability. Surface protein load shifted to lower values with increasing whey-to-milk protein ratio. Yet, protein-protein interactions and droplet flocculation were enhanced by pasteurization and/or homogenization in emulsions with additional WPC, which hindered displacement of proteins by SE. Formation of small fat crystals were favored by increase in whey-to-milk protein ratios, although fat nucleation and crystal growth were depressed in the absence of SE. The presence of SE facilitated formation of smaller fat crystals and dense crystal network compared with emulsions without SE at the same protein composition. Small amplitude oscillatory deformation experiments revealed increased whey protein addition enhanced the stiffness of crystal network, although the crystalline fat content reduced. The whipped-frozen emulsions containing SE were distinguished by higher partial coalescence degrees (19.52%–254.51%) compared to corresponding emulsions without SE (12.82%–41.67%). The maximum partial coalescence degree was elicited at whey-to-milk protein ratio of 7:3 with SE which was ascribed to a weak adsorbed layer and increase of crystal growth dimensions combined with stiff crystal network. Correlation analysis evidenced enhancement of fat flocculation and partial coalescence accounted for increased overrun and meltdown stability of ice cream, respectively. Findings from this work are helpful to illustrate mechanism behind the stability of aerated emulsions.

Tuning the coalescence degree in the growth of Pt-Pd nanoalloys.

Coalescence is a phenomenon in which two or more nanoparticles merge to form a single larger aggregate. By means of gas-phase magnetron-sputtering aggregation experiments on Pt–Pd nanoalloys, it is shown that the degree of coalescence can be tuned from a growth regime in which coalescence is negligible to a regime where the growth outcome is dominated by coalescence events. This transition is achieved by varying both the length of the aggregation zone and the pressure difference between the aggregation and the deposition chamber. In the coalescence-dominated regime, a wide variety of coalescing aggregates is produced and analyzed by TEM. The experimental results are interpreted with the aid of molecular-dynamics simulations. This allows to distinguish four different steps through which coalescence proceeds towards equilibrium. These steps, occurring on a hierarchy of well-separated time scales, consist in: (i) alignment of atomic columns; (ii) alignment of close-packed atomic planes; (iii) equilibration of shape; (iv) equilibration of chemical ordering.

Coalescence, crystallographic orientation and luminescence of ZnO nanowires grown on Si(001) by chemical vapour transport

We analyse the morphological, structural and luminescence properties of self-assembled ZnO nanowires grown by chemical vapour transport on Si(001). The examination of nanowire ensembles by scanning electron microscopy reveals that a non-negligible fraction of nanowires merge together forming coalesced aggregates during growth. We show that the coalescence degree can be unambiguously quantified by a statistical analysis of the cross-sectional shape of the nanowires. The examination of the structural properties by x-ray diffraction evidences that the nanowires crystallize in the wurtzite phase, elongate along the c-axis, and are randomly oriented in plane. The luminescence of the ZnO nanowires, investigated by photoluminescence and cathodoluminescence spectroscopy, is characterized by two bands, the near-band-edge emission and the characteristic defect-related green luminescence of ZnO. The cross-correlation of scanning electron micrographs and monochromatic cathodoluminescence intensity maps reveals that: (i) coalescence joints act as a source of non-radiative recombination, and (ii) the luminescence of ZnO nanowires is inhomogeneously distributed at the single nanowire level. Specifically, the near-band-edge emission arises from the nanowire cores, while the defect-related green luminescence originates from the volume close to the nanowire sidewalls. Two-dimensional simulations of the optical guided modes supported by ZnO nanowires allow us to exclude waveguiding effects as the underlying reason for the luminescence inhomogeneities. We thus attribute this observation to the formation of a core–shell structure in which the shell is characterized by a high concentration of green-emitting radiative point defects as compared to the core.

Effect of nano-SiO2 hydrosol on size distribution, coalescence and collapse of entrained air bubbles in fresh cement mortar

In the fresh state of cement-based composite materials, entrained air bubbles change dynamically due to the continuous coalesce and collapse caused by physical and chemical factors. These processes affect the pore structure formed in the later stage. However, only few studies emphasized the process of bubble size refinement and pore evolution. In this paper, attempts have been made to optimize the size distribution of entrained air bubble and prevent the coalescence of fine entrained air bubbles in the fresh air-entraining cement mortar contained nano-SiO2 hydrosol (NSH). Two different kinds of commercial air entraining agents (AEAs) were utilized. The fluidity and initial air content of each mortar set were controlled during the test to prevent the influence on the behavior of entrained bubbles. An Air Void Analyzer (AVA) was used to determine the air size distribution of mortar. The change of fine bubble distribution within 60 min was analyzed to evaluate the degree of coalescence of fine bubbles. By involving a novel method to prepare bubble shell samples, the mechanism of the influence of NSH on the size distribution and trends of entrained air bubble over time was analyzed via micro measurements including X-Ray Diffraction (XRD), Energy-Dispersive X-ray Spectroscopy (EDS), and Scanning Electron Microscope (SEM). Results suggest that the proportion of fine bubbles less than 300 μm in mortar prepared with non-ionic air entraining agent increases with adding NSH, which effectively fined the size distribution of bubbles, while the trend of mortar prepared with anionic air entraining agent is not obvious. The coalescence degree of fine bubbles is effectively inhibited by adding nano-SiO2 into air-entraining mortar, and the inhibition effect decreases with the increase of the content of nano-SiO2. XRD, EDS, and SEM data analysis proved the adsorption of nano-SiO2 on the bubble shell entrained by AEAs. The composition of air bubble shell has a great influence on the adsorption and effect of nano-SiO2. Nano-SiO2 adsorbed on the surface of bubble shell can enhancing mechanical strength of bubble shell and accelerating the hydration of tricalcium silicate at the same time, thus affecting the behavior of the bubble. At last, the method of optimizing air bubble distribution by incorporating nano-SiO2 is suggested for air-entraining cement-based composites mixed with non-ionic air entraining agent.

Effect of Ionic Strength on Freeze–Thaw Stability of Glycosylated Soy Protein Emulsion

AbstractThis study used Soy Protein Isolate (SPI), Soy Protein Isolate Hydrolysates (SPH) and Dextran (D) as raw materials. Covalent compounds were prepared by grafting soy protein isolate and soy protein isolate hydrolysate with dextran by water‐heating method, which were SPI‐D and SPH‐D, respectively. The effect of ionic strength (0–500 mM) on the freeze–thaw stability of SPI, SPI‐D, and SPH‐D emulsions was investigated. Fourier transform infrared analysis and Fluorescence emission spectroscopy analysis indicated that the structure of the protein changed. In this study, it was found that with the increase of ionic strength, the zeta potential of the three samples presented a downward trend and the surface hydrophobicity first decreased and then increased. The addition of ions effectively improved the freeze–thaw stability of the emulsions. The particle size of the emulsions changed little after freeze–thaw cycles, and coalescence degree, creaming index, and oiling off significantly decreased. Especially when the ionic strength reached 300 mM, the degree of coalescence was 248.46%, 170.92%, and 167.77%, respectively, and the oiling off was also reduced by 68.52%, 68.25%, and 59.92%, respectively. The creaming index of the SPI emulsion was 48.49% lower than the creaming index without ions. However, when the ionic strength exceeded 300 mM, the coalescence degree, creaming index, and oiling off of the emulsions increased. Optical microstructures also found that at ionic strength of 300 mM, the oil droplets produced by the three kinds of emulsion after freeze–thaw were smaller than those without ions.

The radiation assisted-Maillard reaction comprehensively improves the freeze-thaw stability of soy protein-stabilized oil-in-water emulsions

For the first time, the irradiation technology combined with Maillard reaction were used to improve the freeze - thaw stability of soybean protein emulsion. The freeze-thaw stability of emulsions prepared with soy protein isolate (SPI), soy protein isolate and maltose mixture (SPI + M) or glycosylated soy protein isolate with maltose formed by irradiation of 7.5 kGy and 12.5 kGy (named SPI-M7.5 and SPI-M12.5, respectively) was compared. Fourier transform infrared spectroscopy, fluorescence spectroscopy and ultraviolet spectroscopy confirmed the change of the structure of soy protein isolate, indicating that maltose was covalently linked to soybean protein isolate. Scanning electron microscopy showed that the modified protein particles were more loose, uniform in size, and significantly reduced in molecular aggregation than untreated protein. The freeze-thaw stability of SPI, SPI + M, and SPI-M7.5 and SPI-M12.5 emulsions was evaluated. It was found that after three freeze-thaw cycles, the creaming index, oiling off, particle size, coalescence degree and flocculation degree of emulsions prepared with irradiated SPI samples were all lower than those prepared with SPI and SPI + M. Zeta potential, laser confocal and optical microscopy showed that the emulsion was still in a relatively stable state, and the SPI-M7.5 emulsion after freeze-thaw treatment was more stable than the SPI-M12.5 emulsion.

How Valuable Is a Presidential Cabinet? Measuring Ministries’ Political Attractiveness in Brazil

ABSTRACTHow valuable is a cabinet position? While the current literature does not ignore the reality that ministries differ from one another, it does not offer either theoretical or methodological procedures to assess such differences. This article introduces a refined measure of coalescence degree that considers several characteristics ministries may have, as well as politicians’ preferences about cabinet appointments. We estimate the effect of this alternative measure of coalescence on the president’s legislative success using large Brazilian datasets from 1995 to 2014 and an elite survey conducted with 62 Brazilian legislators. Controlling for other coalition management variables (coalition size and ideological heterogeneity), our refined coalescence metric turns out to be a more appropriate tool to assess the president’s performance in Congress.