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The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Ultra-instantaneous UHT (UI-UHT, >155°C, <0.1 s) treated milk exhibits higher retention of active protein than regular UHT milk. However, UI-UHT products demonstrate increased susceptibility to destabilization during storage. This study aimed at monitoring the destabilizing process of UI-UHT milk across different storage temperatures and uncovering its potential mechanisms. Compared with regular UHT treatment, ultra-instantaneous treatment markedly accelerated the milk's destabilization process. Aged gel formation occurred after 45 d of storage at 25°C, whereas creaming and sedimentation were observed after 15 d at 37°C. To elucidate the instability mechanism, measurements of plasmin activity, protein hydrolysis levels, and proteomics of the aged gel were conducted. In UI-UHT milk, plasmin activity, and protein hydrolysis levels significantly increased during storage. Excessive protein hydrolysis at 37°C resulted in sedimentation, whereas moderate hydrolysis and an increase in protein particle size at 25°C resulted in aged gel formation. Proteomics analysis results indicated that the aged gel from UI-UHT milk contained intact caseins, major whey proteins, and their derived peptides. Furthermore, specific whey proteins including albumin, lactotransferrin, enterotoxin-binding glycoprotein PP20K, and MFGM proteins were identified in the gel. Additionally, MFGM proteins in UI-UHT milk experienced considerable hydrolysis during storage, contributing to fat instability. This study lays a theoretical foundation for optimizing UI-UHT milk storage conditions to enhance the quality of liquid milk products. [Display omitted] [ABSTRACT FROM AUTHOR]

This work investigates the demixing behavior of Pickering emulsions consisting of water, n-hexadecane, and two different types of Pickering particles. The first type is uniform, and the second consists of one-side modified Janus particles influencing the emulsion behavior significantly. Both particle types are able to stabilize the emulsions, but lead to clear differences in the emulsion drop size and size distribution. This results in different creaming times varying between minutes and hours and different clearance processes of the water excess phase. Large pH effects were found in addition. At some conditions, non-adsorbed particles were observed that sediment over time in addition to the creaming of the emulsion. [ABSTRACT FROM AUTHOR]

Summary: The use of two emulsifiers to fabricate a composite emulsifier is a useful strategy used to strengthen the emulsifying capacity. To investigate the feasibility of using soy protein isolate (SPI) to stabilise Pickering emulsions stabilised by soy peptide nanoparticles (SPNs), the SPI was introduced into the SPN system to fabricate SPI‐SPN complex emulsifiers, and the effects of the SPI on the properties of the SPNs and SPN‐stabilised emulsions were investigated with various oil fractions. The addition of SPI significantly reduced the particle sizes and surface hydrophobicities. Furthermore, the SPI increased the structural rearrangements of the SPNs at the oil–water interface. Compared with emulsions stabilised with the SPN alone, the droplet sizes of the SPI‐SPN emulsions were smaller, and the interface protein adsorption percentages were lower for all oil fractions. The viscosity of the SPI‐SPN emulsion was higher than that of the SPNs emulsion at Φ ≤ 0.60. Decreases in G′ and G″ were observed when the SPI was added at all Φ values tested. More importantly, the added SPI markedly enhanced the creaming stabilities of the SPN emulsions at low Φ (≤0.40). These results confirmed that SPI improved the emulsifying activity of the SPNs and enhanced the stabilities of Pickering emulsions stabilised with SPNs at low Φ. [ABSTRACT FROM AUTHOR]

A significant number of foods are manufactured in the form of emulsions. A typical example of such a product is mayonnaises, which vary in oil content. However, as a macroemulsion, they are a thermodynamically unstable system. Therefore, the physical instability associated with processes such as flocculation, coalescence and Ostwald ripening leads to separation of the oil and water phases over time. This is especially typical of low-fat mayonnaises. As the oil content in the sauce decreases, it is necessary to add various biopolymers to ensure its stability over time. Predicting physical instability is important for food technology development purposes, and especially for reduced oil systems as the most challenging task in terms of system stabilization. In the first approximation according to the Stoke's model, the stability of an emulsion is affected by microstructural characteristics such as as the droplet size and the rheological properties of the emulsions. The combination of this approximation with the generalized Casson's rheological model for structured liquid systems allows us to propose an approach for estimating the rate of emulsion creaming. The parameters used for calculations are determined from rheology and laser diffraction data for mayonnaise samples. The approach is devoid of empirical variables, since all parameters have a physical meaning on the basis of the kinetic model of destruction–recovery of the structural aggregates of the system. Calculations were carried out for a series of commercial mayonnaises (CMs) and developed low-fat mayonnaise (LFM). The results make it possible to evaluate the physical stability of emulsions, as well as the influence of rheological and microstructural characteristics on the texture of the final product during its shelf life. [ABSTRACT FROM AUTHOR]

Employer engagement is increasingly emphasised in the context of efforts to bring more disadvantaged people into work. A new approach in the Norwegian Employment and Welfare Service (NAV) combines demand-side and supply-side measures in a 'combined workplace-oriented approach'. Through qualitative interviews with frontline staff – including job coaches following the Supported Employment (SE) method – the paper examines the intermediary role of the street-level organisation (SLO) through the targeted use of SE methods directed at young users and employers. The findings suggest that young users are 'creamed by motivation' into the SE programme, which can be explained by the importance the SLO places: on maintaining inter-organisational relationships with employers, on job coaches' performance goals and the need to uphold an organisational structure in the SLO that seemingly works efficient to shift caseloads of young unemployed into work. Hence, creaming is not specific to outsourcing but can also occur when insourcing employer engagement services into a public SLO. Although relational work directed at both employers and young clients is seen as the benefit of a combined workplace-oriented approach, it appears a rather flimsy foundation for successful ALMPs unless supported by more structural demand-side measures. [ABSTRACT FROM AUTHOR]

ABSTRACT: Shiga toxin-producing Escherichia coli (STEC) are widely detected in raw milk products intended for human consumption. Although STEC are a worldwide public health problem, the pathogenicity of STEC in cheese remains unclear. In fact, bacterial association with compounds in raw milk cheeses could reduce their pathogenicity. A previous study showed the association of 2 STEC strains with raw milk cream in a natural creaming assay. Different concentrations of each strain were required to saturate the cream. In this study, we hypothesized that all STEC strains could be associated with milk fat globules (MFG) in raw milk and that the bacterial load required for saturation of the cream is serotype dependent. We evaluated the affinity of STEC strains belonging to the O157:H7, O26:H11, and O103:H2 serotypes for bovine raw milk cream and analyzed saturation of the cream layer by natural creaming assay. We used 12 STEC strains and 3 strains belonging to another pathotype to assess the effects of serotypes on this phenomenon. We performed sucrose density gradient centrifugation assays with 2 STEC model strains to confirm the results obtained by natural creaming. The localization of STEC within MFG-enriched creams was observed by confocal and electron microscopy. We recovered approximately 10 times more STEC from the cream layer after natural creaming than from raw bovine milk. The concentration of STEC required to saturate the cream layer (the saturation concentration) was estimated for each strain by nonlinear regression, highlighting a strain and serotype effect. Moreover, the concentration of STEC in the cream was milk fat level dependent. However, even in nonsaturating conditions, a high level of STEC was still present in the aqueous phase, after fat separation. Thus, natural creaming should not be used as the sole preventive measure to remove STEC from naturally contaminated raw milk. The results of our study suggest that cream saturation is a complex mechanism, most likely involving specific interactions between STEC and raw MFG.

A significant number of foods are manufactured in the form of emulsions. A typical example of such a product is mayonnaises, which vary in oil content. However, as a macroemulsion, they are a thermodynamically unstable system. Therefore, the physical instability associated with processes such as flocculation, coalescence and Ostwald ripening leads to separation of the oil and water phases over time. This is especially typical of low-fat mayonnaises. As the oil content in the sauce decreases, it is necessary to add various biopolymers to ensure its stability over time. Predicting physical instability is important for food technology development purposes, and especially for reduced oil systems as the most challenging task in terms of system stabilization. In the first approximation according to the Stoke’s model, the stability of an emulsion is affected by microstructural characteristics such as as the droplet size and the rheological properties of the emulsions. The combination of this approximation with the generalized Casson’s rheological model for structured liquid systems allows us to propose an approach for estimating the rate of emulsion creaming. The parameters used for calculations are determined from rheology and laser diffraction data for mayonnaise samples. The approach is devoid of empirical variables, since all parameters have a physical meaning on the basis of the kinetic model of destruction–recovery of the structural aggregates of the system. Calculations were carried out for a series of commercial mayonnaises (CMs) and developed low-fat mayonnaise (LFM). The results make it possible to evaluate the physical stability of emulsions, as well as the influence of rheological and microstructural characteristics on the texture of the final product during its shelf life.

Shiga toxin-producing Escherichia coli (STEC) are widely detected in raw milk products intended for human consumption. Although STEC are a worldwide public health problem, the pathogenicity of STEC in cheese remains unclear. In fact, bacterial association with compounds in raw milk cheeses could reduce their pathogenicity. A previous study showed the association of 2 STEC strains with raw milk cream in a natural creaming assay. Different concentrations of each strain were required to saturate the cream. In this study, we hypothesized that all STEC strains could be associated with milk fat globules (MFG) in raw milk and that the bacterial load required for saturation of the cream is serotype dependent. We evaluated the affinity of STEC strains belonging to the O157:H7, O26:H11, and O103:H2 serotypes for bovine raw milk cream and analyzed saturation of the cream layer by natural creaming assay. We used 12 STEC strains and 3 strains belonging to another pathotype to assess the effects of serotypes on this phenomenon. We performed sucrose density gradient centrifugation assays with 2 STEC model strains to confirm the results obtained by natural creaming. The localization of STEC within MFG-enriched creams was observed by confocal and electron microscopy. We recovered approximately 10 times more STEC from the cream layer after natural creaming than from raw bovine milk. The concentration of STEC required to saturate the cream layer (the saturation concentration) was estimated for each strain by nonlinear regression, highlighting a strain and serotype effect. Moreover, the concentration of STEC in the cream was milk fat level dependent. However, even in nonsaturating conditions, a high level of STEC was still present in the aqueous phase, after fat separation. Thus, natural creaming should not be used as the sole preventive measure to remove STEC from naturally contaminated raw milk. The results of our study suggest that cream saturation is a complex mechanism, most likely involving specific interactions between STEC and raw MFG. [ABSTRACT FROM AUTHOR]

Achieving equity in welfare provision depends on accurate understandings of the work of street‐level bureaucrats. We explore the role of emotions when caseworkers prioritise cases. While creaming of clients whom street‐level bureaucrats consider 'likely to succeed' is acknowledged as a way of rationing scarce resources, research tends to reject emotional involvement as bias, or neglect emotions in creaming‐practices. This may produce inaccurate portrayals of how street‐level bureaucrats prioritise cases. We challenge existing perspectives by bridging the literature on creaming and the sociology of emotions. We did ethnography and interviews with Norwegian caseworkers tasked with integrating migrant clients into the labour market. These caseworkers cream cases according to institutional/discursive understandings of 'star candidates' and rely on their emotions as embodied knowledge. We conceptualise such processes as emotional creaming, which unpacks a central, yet overlooked part of how street‐level bureaucrats prioritise cases. This modifies the depiction of emotions as mainly personal bias. [ABSTRACT FROM AUTHOR]

Context: Full factorial design is effective in predicting the properties optimization and processing conditions of cosmetic emulsions. However, in most factorial designs, the technological quality and accelerated stability tests of emulsions are not included together as dependent variables. Aims: To predict the technological quality and physical stability of model cosmetic emulsions from the combination of formulation and processing factors using a 23 full factorial design. Methods: A 23 full factorial design with 95 % of confidence was generated in order to evaluate the influence of critical factors during the manufacture of cosmetic emulsions on their quality and physical stability. Emulsifier, concentration of stearic acid (formulation factors) and type of cooling (processing factor) were the independent variables, whereas spreadability, bulk density and pH were dependent variables for technological quality and centrifugation, heating-cooling and freeze-thaw cycles were dependent variables for physical stability of the emulsions. All cosmetic emulsions were prepared with a low stirring speed of 100 rpm. Results: The formulation containing 1% w/w sodium lauryl sulfate, 1.05% w/w stearic acid and prepared with continuous cooling, did not show indicative changes of physical instability by visual inspection after accelerated physical stability tests. These results were confirmed with emulsions stored for 12 and 24 months using real storage conditions. However, formulations containing an emulsifier blend composition (Tween 80: Sodium lauryl sulfate, 2:1 w/w), showed signs of creaming after these tests. Conclusions: Sodium lauryl sulfate at 1 % w/w, increased the physical stability of the emulsions by increasing their consistency and by other possible mechanisms. Real storage conditions confirmed the stability prediction performed using the combination of accelerated stability tests (centrifugation/cooling-heating/freeze-thaw cycles), aided by the purposed full factorial design.

This research examines the experiences of unemployed workers who report they have been parked or creamed by their employment services provider. Using focus group methodology, the research findings suggest that the experiences of being parked or creamed do not simply reflect quantitative metrics such as appointment frequency, and are experienced primarily as reflections of the quality of the transactions that occur in appointments. The findings suggest that parking and creaming are pervasive with harmful consequences for unemployed workers. Parking, on the one hand, appears to exacerbate the scarring effect of unemployment. Creaming, on the other hand, is not experienced as a benefit because rapid placement into employment is likely to be directed toward underemployment or precarious employment rather than sustainable employment. A second type of creaming is also described, where providers seek to take credit, sometimes coercively, for unemployed workers finding their own jobs. The findings also suggest that the Department of Employment's actions to date to curb the practices have not been successful and could be improved if unemployed workers were more clearly recognised as having a stake in the provision of high‐quality employment services and given suitable mechanisms to identify and select providers that will not park or cream them. [ABSTRACT FROM AUTHOR]

The consumption of food with health benefits is growing today worldwide. This study was designed in order to incorporate papaya dietary fibre concentrates (DFCs) from peel and pulp dehydrated with the use of microwave (MW), or convection with hot air (CV) in oil-in- water emulsions. Results of studies indicated that Pulp DFC produced more stability to creaming (18 weeks) than Peel DFC (6 weeks). It was found that peel DFCs exerted up to 30% reduction in lipid peroxidation in comparison to the reference system during storage. Rheological analysis showed a similar behaviour when emulsions were mixed with pulp DFCs either dehydrated by MW or CV, while the dressing with peel DFCs had a much lower consistency than the former. The analysis of the emulsions micro-structure showed a polydisperse system of oil droplets and fiber structures trapping oil. Finally, emulsions with pulp DFCs showed a better consumer´s acceptance. These results also suggested that the use of DFCs may have high industrial potential in contributing to dietary fibre enrichment through technological intervention of emulsion formulation by papaya pulp and peel, increasing antioxidant property, consistency and stability during storage. [ABSTRACT FROM AUTHOR]

A set of protein-stabilised emulsions at pH 7.0, pH 6.0, and pH 5.0, and their counterpart surfactant emulsions, was designed with near-identical droplet size distribution and phase volume to study the specific contribution of hydrodynamic and pair potential interactions to the interfacial mechanisms of these emulsions systems. In this way, further the interfacial layer of these creaming emulsions to enhance perceived fat content could be manipulated. Creaming behaviour, surface shear, and bulk rheological measurements were performed. This work reflects the great importance of local pair potential in the formation of a highly viscoelastic interfacial film, which could be manipulated changing the surface charge of the protein to develop a well-packed cream layer in the protein-stabilised emulsions.

Gravity separation of liquid-liquid dispersions is present in many industrial applications, and it involves the complex governing mechanisms of creaming and coalescence in concentrated mixtures. The aim of this work is to model the laminar creaming zone of batch gravitational separation with coalescence using CFD tools. The numerical results were compared to the experimental decay curves of bottle tests. The initial DSD representation by the population balance model was obtained with the Gauss-Legendre Quadrature. The number of velocity groups and the application range of the drag modifier showed to be a function of the initial DSD profile and polydispersity, respectively. The coalescence models evaluated were the constant coalescence efficiency, the critical approach velocity and the film drainage for a deformable partially mobile interface. The coalescence models parameters were calibrated for a determined initial condition (phases volume fraction and droplet size distribution (DSD)) and then applied for different initial conditions. All models were able to model the separation of all initial conditions with the same calibrated parameters, although the drainage model did not need to be calibrated. This suggests that when employed in the modeling of a continuous separator, these can be calibrated by the decay curves of bottle tests. [ABSTRACT FROM AUTHOR]

Certain gas-filled colloidal particles expand upon heating. If such particles are surface-active and stabilize aqueous foams, do the foams grow with temperature as particles expand? Aqueous foams were stabilized with hollow micro-spherical particles that are partially wetted by water and grow upon heating. Foams were prepared using two different approaches, both of which led to their growth. In the first, water was heated to various temperatures (40–80 °C) and aerated in the presence of the particles. In the second, water at room temperature was aerated in the presence of the particles and then heated to various temperatures (40–85 °C). Regardless of the method, foam volume began to increase on raising the temperature to the onset of particle growth (60 °C) as expected and increased with increasing temperature. However, placing the particles on hot water (80 °C) and waiting for several minutes (≤2.5) before aeration resulted in more growth. The volume of foam after growth remained unchanged after cooling for over six months, giving rise to ultra-stable foams. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) have been studied for several decades to understand and determine their mechanism and interaction within the matrix into which they are introduced. This study aimed to determine the spatial distribution of Lacticaseibacillus rhamnosus GG (LGG) in a dairy matrix and to decipher its behaviour towards milk components, especially fat globules. Two strains of this widely studied bacterium with expected probiotic effects were used: LGG WT with pili on the cell surface and its pili-depleted mutant—LGG ΔspaCBA—in order to determine the involvement of these filamentous proteins. In this work, it was shown that LGG ΔspaCBA was able to limit creaming with a greater impact than the wild-type counterpart. Moreover, confocal imaging evidenced a preferential microbial distribution as aggregates for LGG WT, while the pili-depleted strain tended to be homogenously distributed and found as individual chains. The observed differences in creaming are attributed to the indirect implication of SpaCBA pili. Indeed, the bacteria-to-bacteria interaction surpassed the bacteria-to-matrix interaction, reducing the bacterial surface exposed to raw milk. Conversely, LGG ΔspaCBA may form a physical barrier responsible for preventing milk fat globules from rising to the surface.

Oil-in-water emulsions are the main component of creamers, which are used to cream cold or hot coffee. These emulsions must provide the required lightening power and remain physically stable when introduced into hot acidic coffee solutions. In this study, model oil-in-water emulsions stabilized with mixed emulsifiers of sodium caseinate (0.5%) and soy lecithin (0.5%) were fabricated and their physical properties were examined over a range of pH values (pH 3.5 to 7). These model oil-in-water emulsions had strong lightening power (L* ≈ 87) and good physical stability from pH 5.5 to 7 but were unstable to gravitational separation below pH 5 due to caseinate aggregation around its isoelectric point. Addition of λ-carrageenan (0.05 to 0.175%) to the formulations prior to homogenization effectively improved their pH stability, while addition of κ-carrageenan was ineffective. The significantly higher level of sulfated ester groups in λ-carrageenan may have created a strong electrostatic repulsion between the oil particles, inhibiting their association. Our study suggests that some of the caseinate in coffee creamers can be replaced with plant-based lecithins, but that a plant-based polysaccharide is also needed to ensure their stability when added to hot acidic coffees. Unlabelled Image • More consumers are buying plant-based milk for health and sustainability reasons. • Model creamers were made with dairy and plant emulsifiers as a flexitarian approach. • Model creamers had similar appearance and physical properties to commercial creamer. • Model creamers made with milk caseinate aggregated at and below its isoelectric point. • λ-Carrageenan improved physical stability of model creamers made with caseinate. [ABSTRACT FROM AUTHOR]

The time–temperature superposition principle (TTSP) was applied to the destabilization kinetics of a pharmaceutical emulsion. The final goal of this study is to predict precisely the emulsion stability after long-term storage from the short-period accelerated test using TTSP. As the model emulsion, a cream preparation that is clinically used for the treatment of pruritus associated with chronic kidney disease was tested. After storage at high temperatures ranging from 30 to 45 °C for designated periods, the emulsion state was monitored using magnetic resonance imaging, and then the phase separation behaviors observed were analyzed according to the Arrhenius approach applying TTSP. The Arrhenius plot showed a biphasic change around 35 °C, indicating that the separation behaviors of the sample were substantially changed between the lower (30–35 °C) and higher (35–45 °C) temperature ranges. This study also monitored the coalescence behavior using a backscattered light measurement. The experiment verified that the destabilization was initiated by coalescence of oil droplets and then it eventually led to obvious phase separation via creaming. Furthermore, we note the coalescence kinetics agreed well with the phase separation kinetics. Therefore, in the case of the sample emulsion, the coalescence behavior has a dominant influence on the destabilization process. This study offers a profound insight into the destabilization process of pharmaceutical emulsions and demonstrates the promising applicability of TTSP to pharmaceutical research. [ABSTRACT FROM AUTHOR]

The main aim of this work is to produce foam rubber using the Dunlop process from in-house creamed latex and compare it with commercial centrifuged latex. The dry rubber content of creamed latex is higher than that of fresh natural latex and traditional centrifuged latex. The creaming agent plays a major role during the preparation of foam rubber and therefore defines the density as well as the elastic and mechanical properties of the final product. Scanning electron microscopy images show lower porosity in rubber foam made from creamed latex compared to that from centrifuged latex. This methodology should have a highly positive impact on the rubber community in both upstream and downstream rubber industries. [ABSTRACT FROM AUTHOR]

The process of agglutination causes firm cream layers in bovine milk, and a functioning agglutination mechanism is paramount to the quality of non-homogenized milks. The phenomenon is not well-described, but it is believed to occur due to interactions between immunoglobulins (Ig) and milk fat globules. For the first time, this paper demonstrates how the process of agglutination can be visualized using confocal laser scanning microscopy, rhodamine red and a fluoresceinisothiocynat-conjugated immunoglobulin M antibody. The method was used to illustrate the effect on agglutination of storage temperature and pasteurization temperature. Storage at 5 °C resulted in clearly visible agglutination which, however, was markedly reduced at 15 °C. Increasing storage temperature to 20 or 37 °C cancelled any detectable interaction between IgM and milk fat globules, whereby the occurrence of cold agglutination was documented. Increasing 20 s pasteurization temperatures from 69 °C to 71 °C and further to 73 °C lead to progressively higher inactivation of IgM and, hence, reduction of agglutination. Furthermore, 2-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that changes in storage temperature caused a redistribution of Ig-related proteins in milk fat globule membrane isolates. Poly-immunoglobulin G receptor was present in milk fat globule preparations stored at cold (4 °C) conditions, but absent at storage at higher temperature (25 °C). The findings provide valuable knowledge to dairy producers of non-homogenized milk in deciding the right pasteurization temperature to retain the crucial agglutination mechanism. [ABSTRACT FROM AUTHOR]

Abstract Mono- and diglycerides (MDGs) are emulsifiers used to modify physical properties and creaming stability in protein-stabilised emulsions. This study aims to understand the effect of different MDGs and sodium stearate on oil droplet size and creaming stability of emulsions. Model emulsions with eight MDG compositions and a control (protein only) were prepared by microfluidisation. Emulsion droplets and creaming stability were characterised by droplet size, zeta potential, viscosity and creaming index during aging (28 days at 25 °C). Emulsions containing 0.2% MDGs produced 15–30% smaller oil droplets and 17–27% lower polydispersity indices compared to the control. Sodium stearate (6% of MDGs) increased zeta potential by 12.6–17.3 mV in emulsions containing saturated MDGs and 1.8–5.0 mV in unsaturated MDGs. Unsaturated MDGs showed better creaming stability than the control after 28 days of aging with no improvement observed for saturated MDGs. Unsaturated MDGs are promising emulsifiers to improve creaming stability of protein-stabilised emulsions. Highlights • Formulation of protein-stabilised oil-in-water emulsions containing mono- and diglycerides. • Mono- and diglycerides reduces the droplet size and size-range distributions of an emulsion. • Sodium stearate increases the negativity of zeta potential in an emulsion. • Unsaturated mono- and diglycerides are effective for emulsion stability towards creaming. [ABSTRACT FROM AUTHOR]

Demand for ultra‐high‐temperature (UHT) milk and milk protein‐based beverages is growing. UHT milk is microbiologically stable. However, on storage, a number of chemical and physical changes occur and these can reduce the quality of the milk. These changes can be sufficiently undesirable so as to limit acceptance or shelf life of the milk. The most severe changes in UHT milk during storage are age gelation, with an irreversible three‐dimensional protein network forming throughout, excessive sedimentation with a compact layer of protein‐enriched material forming rapidly at the bottom of the pack, and creaming with excessive fat accumulating at the top. For age gelation, it is known that at least two mechanisms can lead to gelation during storage. One mechanism involves proteolytic degradation of the proteins through heat‐stable indigenous or exogenous enzymes, destabilizing milk and ultimately forming a gel. The other mechanism is referred to as a physico‐chemical mechanism. Several factors are known to affect the physico‐chemical age gelation, such as milk/protein concentration, heat load during processing (direct compared with indirect UHT processes), and milk composition. Similar factors to age gelation are known to affect sedimentation. There are relatively few studies on the creaming of UHT milk during storage, suggesting that this defect is less common or less detrimental compared with gelation and sedimentation. This review focuses on the current state of knowledge of age gelation, sedimentation, and creaming of UHT milks during storage, providing a critical evaluation of the available literature and, based on this, mechanisms for age gelation and sedimentation are proposed. [ABSTRACT FROM AUTHOR]

Suspensions and emulsions are prone to kinetic instabilities of sedimentation and creaming, wherein the suspended particles and droplets fall or rise through a matrix fluid. It is important to understand and quantify sedimentation and creaming in such dispersed systems as they affect the shelf-life of products manufactured in the form of suspensions and emulsions. In this article, the unhindered and hindered settling/creaming behaviors of conventional emulsions and suspensions are first reviewed briefly. The available experimental data on settling/creaming of concentrated emulsions and suspensions are interpreted in terms of the drift flux theory. Modeling and simulation of nanoparticle-stabilized Pickering emulsions are carried out next. The presence of nanoparticles at the oil/water interface has a strong influence on the creaming/sedimentation behaviors of single droplets and swarm of droplets. Simulation results clearly demonstrate the strong influence of three-phase contact angle of nanoparticles present at the oil/water interface. This is the first definitive study dealing with modeling and simulation of unhindered and hindered creaming and sedimentation behaviors of nanoparticle-stabilized Pickering emulsions.

In this study, the possibility of producing stable O/W emulsions encapsulating rutin in oil droplets stabilized by soy lecithin and chitosan has been demonstrated. Emulsions were prepared using rotor-stator homogenization, which relied on the adsorption of cationic chitosan polymer to anionic oil droplet stabilized with lecithin. Results showed that emulsion stability index ( ESI ), mean droplet size ( d (3,2) ), and rheological properties of emulsions were principally dependent on the chitosan concentrations. d (3,2) of emulsions was found increasing with the rise of chitosan concentration and reached a maximum value of 520 nm at 0.5% (w/w) chitosan. The emulsion destabilization over time was governed principally by coalescence and creaming instability mechanisms as demonstrated by Lumisizer’ transmission profiles. All emulsions flow curves showed a near-Newtonian behavior as depicted by Power Law model results. Thermal degradation kinetics of rutin emulsions were studied at selected temperatures (4; 25; 40 °C). Chitosan concentration showed a good impact on the reduction of thermal degradation rate ( k ) of rutin emulsions during 30 days of storages, thus increasing rutin half-life ( t 1/2 ). The lowest degradation rate occurred in the rutin emulsion stabilized with 2% (w/w) chitosan. Results indicated that the thermal degradation of rutin followed first-order reaction kinetics, and they could be expressed by Arrhenius equation. The activation energy value for rutin degradation was 27.8 kJ mol −1 with 2% (w/w) chitosan. These results implied that the physicochemical stability of rutin emulsions has been improved by addition of chitosan. [ABSTRACT FROM AUTHOR]

In this work, we investigated the influence of the addition of flaxseed gum (FG) (0.1–0.5%, w/w) and NaCl (0–0.6 M) on the stability of 10% (w/w) melted lard emulsions. The particle size, ζ-potential, rheological properties, creaming stability, microstructure, and nuclear magnetic resonance spectra of the emulsions were analyzed. The results showed the particle size in emulsions significantly decreased with increasing FG concentrations and the smallest droplets in emulsions with 0.5% (w/w) FG were obtained. The rheological property results revealed the presence of a gel-like behavior in emulsions containing 0.5% (w/w) FG. The addition of NaCl destabilized the emulsions by reducing the electrostatic repulsion, which resulted in larger particle size and lower ζ-potential. The salt stability of the emulsions was significantly improved by increasing the amount of FG. Emulsions prepared with 0.5% (w/w) FG were stable under lower NaCl (0–0.4 M) concentrations. Using low-field nuclear magnetic resonance (NMR) spectroscopy, we obtained shorter T 2 values in emulsions containing 0.1% (w/w) FG or 0.6 M NaCl. The 1 H and 13 C high-field NMR spectra showed an increase of line-widths as FG concentration increased and NaCl concentration deceased, which confirmed the increasing interaction between the FG and oil molecules. This study would help to widen the application of flaxseed gum which is insensitive to NaCl, and also contribute to the understanding of gum-lard interaction in emulsion. [ABSTRACT FROM AUTHOR]

The processing of milk using high-pressure technologies has been shown to dissociate casein micelles, denature whey proteins, and change the appearance and rheological properties of milk. A novel high-pressure processing technology called high-pressure-jet (HPJ) processing is currently being investigated for use in the food industry. Few studies have evaluated the effects of HPJ technology on dairy foods. The present study investigated the physicochemical and foaming properties of homogenized pasteurized whole milk processed at pressures from 0 to 500 MPa using HPJ processing. The apparent particle size exhibited a monomodal distribution in whole milk samples processed up to 125 MPa and a bimodal distribution for samples processed at 250, 375, and 500 MPa. The viscosity increased from approximately 2 to 5 mPa·s when whole milk was processed using HPJ at 375 MPa, and foam expansion increased from approximately 80 to 140% after processing at >125 MPa. Foam stability was limited to pressures in the 375 to 500 MPa range. We hypothesized that the increase in apparent particle size was due to the dissociation of casein micelles into surface-active casein protein monomers, and the formation of casein– casein and casein–fat particles. Ultracentrifugation of samples into 3 milk fractions (supernatant, serum, and precipitate), and subsequent fat and protein analysis on the 3 fractions, showed that a strong interaction between casein proteins and fat triglycerides occurred, evidenced by the increase in fat content associated with the precipitate fraction with increasing pressure. This suggests that stable casein–fat aggregates are formed when whole milk is processed using HPJ at pressure >125 MPa. [ABSTRACT FROM AUTHOR]

The present study elucidates the creaming phenomenon of mineral oil-in-water macroemulsion using a new noninvasive method based on turbidimetry. Additionally, microscopic observation of the phenomenon is carried out to derive an in-depth understanding of the mechanisms. Accumulation of the particles in the emulsions under the formed cream is monitored during a relatively prolonged period of time. Backflow of continuous and dispersed phases in temporary channels is observed at the proximity of the cream. In addition to the backflow, a high traffic density of the dispersed particles and deflocculation of the cream are the main reasons for the accumulation of the dispersed phase particles and a temporary stability against creaming. The deflocculation hinders cream growth and increases the stratification of the cream. A low concentration zone of the dispersed phase with the width of ∼100 µm is observed under the cream. [ABSTRACT FROM AUTHOR]

Fat separation, gelation or sedimentation of UHT milk during shelf-storage represent instability phenomena causing the product rejection by consumers. Stability of UHT milk is of increasing concern because access to emerging markets currently implies for this product to be stable during shipping and prolonged storage, up to 12 months. The role of microfiltration prior to UHT process in avoiding or retarding the gelation or sediment formation was studied by comparing microfiltered UHT milk to conventional UHT milk. A second trial was set up to study the effects of double ultra-high pressure homogenization in delaying the cream rising and UHT milk homogenized once at lower pressure was taken as control. All milk samples were produced at industrial plant level. Milk packages were stored at 22 °C, opened monthly for visually inspecting the presence of cream layer, gel or sediment and then analysed. Microfiltration markedly delayed the formation of both gel particles and sediment, with respect to the control, and slowed down the proteolysis in terms of accumulation of peptides although no correlation was observed between the two phenomena. The double homogenization, also evaluated at ultra-structural level, narrowed the fat globule distribution and the second one (400 MPa), performed downstream to the sterilization step, disrupted the fat-protein aggregates produced in the first one (250 MPa). The adopted conditions avoided the appearance of the cream layer in the UHT milk up to 18 months. This study contributes important knowledge for developing strategies to delay instability phenomena in UHT milk destined to extremely long shelf storage. [ABSTRACT FROM AUTHOR]

In complex colloidal systems, particle-poor regions can develop within particle-rich phases during sedimentation or creaming. These particle-poor regions are overlooked by 1D profiles, which are typically used to assess particle distributions in a sample. Alternative methods to visualise and quantify these regions are required to better understand phase separation, which is the focus of this paper. Magnetic resonance imaging has been used to monitor the development of compositional heterogeneity in a vesicle-polymer mixture undergoing creaming. T 2 relaxation time maps were used to identify the distribution of vesicles, with vesicle-poor regions exhibiting higher T 2 relaxation times than regions richer in vesicles. Phase separated structures displayed a range of different morphologies and a variety of image analysis methods, including first-order statistics, Fourier transformation, grey level co-occurrence matrices and Moran’s I spatial autocorrelation, were used to characterise these structures, and quantify their heterogeneity. Of the image analysis techniques used, Moran’s I was found to be the most effective at quantifying the degree and morphology of phase separation, providing a robust, quantitative measure by which comparisons can be made between a diverse range of systems undergoing phase separation. The sensitivity of Moran’s I can be enhanced by the choice of weight matrices used. [ABSTRACT FROM AUTHOR]

The impact of pH on the physicochemical properties of 10% menhaden oil-in-water (O/W) emulsions containing 2% whey protein isolate (WPI) and 0.1% xanthan (XG)-locust bean gum (LBG) mixtures was investigated. The O/W emulsions containing 0.1% XG-LBG mixtures were compared to emulsions with 0.1% XG and 0.1% LBG. The results indicated that stability is dependent on pH and biopolymer type. At both pH 3 and 5, emulsions containing either XG or XG-LBG mixtures had large particle sizes, viscosity, droplet aggregation, and creaming index, resulting in poor physical stability which can be related to the adsorbed protein-polysaccharide interactions. At pH7, the XG-LBG emulsions showed the greatest resistance to phase separation and resulted in stable emulsions. Lipid oxidation measurements also indicated that XG-LBG mixtures can be used to form stable emulsions at pH 3 and pH 7. These results have significant implications for the development of novel structures containing lipid phases susceptible to lipid oxidation. [ABSTRACT FROM AUTHOR]

A set of protein-stabilised emulsions at pH 7.0, pH 6.0, and pH 5.0, and their counterpart surfactant emulsions, was designed with near-identical droplet size distribution and phase volume to study the specific contribution of hydrodynamic and pair potential interactions to the interfacial mechanisms of these emulsions systems. In this way, further the interfacial layer of these creaming emulsions to enhance perceived fat content could be manipulated. Creaming behaviour, surface shear, and bulk rheological measurements were performed. This work reflects the great importance of local pair potential in the formation of a highly viscoelastic interfacial film, which could be manipulated changing the surface charge of the protein to develop a well-packed cream layer in the protein-stabilised emulsions. [ABSTRACT FROM AUTHOR]