scholarly journals Lubrication and Sensory Properties of Emulsion Systems and Effects of Droplet Size Distribution

Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3024
Author(s):  
Qi Wang ◽  
Yang Zhu ◽  
Zhichao Ji ◽  
Jianshe Chen

The functional and sensory properties of food emulsion are thought to be complicated and influenced by many factors, such as the emulsifier, oil/fat mass fraction, and size of oil/fat droplets. In addition, the perceived texture of food emulsion during oral processing is mainly dominated by its rheological and tribological responses. This study investigated the effect of droplet size distribution as well as the content of oil droplets on the lubrication and sensory properties of o/w emulsion systems. Friction curves for reconstituted milk samples (composition: skimmed milk and milk cream) and Casein sodium salt (hereinafter referred to as CSS) stabilized model emulsions (olive oil as oil phase) were obtained using a soft texture analyzer tribometer with a three ball-on-disc setup combined with a soft surfaces (PDMS) tribology system. Sensory discrimination was conducted by 22 participants using an intensity scoring method. Stribeck curve analyses showed that, for reconstituted milk samples with similar rheological properties, increasing the volume fraction of oil/fat droplets in the size range of 1–10 µm will significantly enhance lubrication, while for CSS-stabilized emulsions, the size effect of oil/fat droplets reduced to around 1 µm. Surprisingly, once the size of oil/fat droplets of both systems reached nano size (d90 = 0.3 µm), increasing the oil/fat content gave no further enhancement, and the friction coefficient showed no significant difference (p > 0.05). Results from sensory analysis show that consumers are capable of discriminating emulsions, which vary in oil/fat droplet size and in oil/fat content (p < 0.01). However, it appeared that the discrimination capability of the panelist was significantly reduced for emulsions containing nano-sized droplets.

2007 ◽  
Vol 17 (4) ◽  
pp. 42250-1-42250-9 ◽  
Author(s):  
Irina Masalova ◽  
Alexander Ya. Malkin

Abstract The concentration and size dependencies of elastic properties of highly concentrated w/o emulsions were studied. The range of weight concentration of the disperse phase was 90 - 96%, the range of the average droplet size was 16 - 20 mm, and the droplet size distribution remained unchanged. The disperse phase consists of droplets of over-cooled concentrated aqueous solutions of inorganic salts. The concentration range being studied lies above the limit of maximal close packing, j > jm. The droplet size distribution is fairly wide and the shape of droplets is polygonal. These factors alone determine possible new rheological effects, such as the elasticity and visco-plastic behaviour of emulsions, as well as the observed form of concentration and size dependencies of rheological properties of emulsions. The complete flow curves were measured for these fairly new emulsion systems. It emerged that they were similar to the entire concentration and droplet size ranges being studied. The concentration dependencies of the yield stress and storage modules corresponded to the Princen-Kiss theory with critical volume concentration approximately 0.71 - 0.74. However, this theory describes the size dependence of elastic modules incorrectly. A new model is proposed, which correctly describes the dependencies of elastic modules on both determining parameters - those of concentration and droplet size.


1999 ◽  
Vol 110 (2) ◽  
pp. 797-804 ◽  
Author(s):  
L. Ambrosone ◽  
A. Ceglie ◽  
G. Colafemmina ◽  
G. Palazzo

2017 ◽  
Vol 2017 (1) ◽  
pp. 2017-194
Author(s):  
Lin Zhao ◽  
Michel C. Boufadel ◽  
Feng Gao ◽  
Thomas King ◽  
Brian Robinson ◽  
...  

Abstract (2017-194) The presence of methane bubbles in the oil and gas blowout could greatly reduce the oil droplet sizes. Bubbles tend to introduce energy into the system and separate oil droplets from each other. The interaction of oil droplets and gas bubbles in the near field of a blowout was investigated numerically using the VDROP-J model, whose droplet size distribution (DSD) was thoroughly calibrated. For this purpose, a new numerical scheme has been developed in VDROP-J to account for the interaction of gas bubbles and oil droplets in the blowout, giving simultaneous simulation of bubble and droplet size distribution along the discharged plume. Validation shows improvement of the model compared with the one without considering the gas bubble and oil droplet interactions. Effects of gas volume fraction on the droplet formation are also investigated. This new development will enhance the knowledge in subsea oil and gas blowouts.


2014 ◽  
Vol 2014 (1) ◽  
pp. 561-571 ◽  
Author(s):  
Lin Zhao ◽  
Michel C. Boufadel ◽  
E. Eric Adams ◽  
Scott A. Socolofsky ◽  
Kenneth Lee

ABSTRACT This paper presents the details of a numerical model that is capable of simulating the droplet size distribution emanating from blowouts. The model was obtained as a result of combination of traditional mechanistic models developed in reactors with jet (or plume) models to predict the evolution of the plume away from the orifice. Inputs to the model include the energy dissipation rate (or the mixing energy) and holdup, which is the volume fraction of oil in the control volume. These parameters vary as the plume spreads away from the orifice. They have a maximum value near the orifice and rapidly decrease as moving away from the orifice. The model was validated using experimental data available in the literature. Subsequently, the model was used to predict the evolution of droplets in the Deepwater Horizon incident. The model provides the variation of the mean diameter and the droplet size distribution with depths away from the orifice. The sensitivity of different parameters, such as interfacial tension which could present the addition of dispersants was also evaluated.


2006 ◽  
Vol 16 (6) ◽  
pp. 673-686 ◽  
Author(s):  
Laszlo E. Kollar ◽  
Masoud Farzaneh ◽  
Anatolij R. Karev

Author(s):  
Jian Wang ◽  
Jichuan Wu ◽  
Shouqi Yuan ◽  
Wei-Cheng Yan

Abstract Previous work showed that particle behaviors in ultrasonic atomization pyrolysis (UAP) reactor have a great influence on the transport and collection of particles. In this study, the effects of droplet behaviors (i.e. droplet collision and breakage) and solvent evaporation on the droplet size, flow field and collection efficiency during the preparation of ZnO particles by UAP were investigated. The collision, breakage and solvent evaporation conditions which affect the droplet size distribution and flow pattern were considered in CFD simulation based on Eulerian-Lagrangian method. The results showed that droplet collision and breakage would increase the droplet size, broaden the droplet size distribution and hinder the transport of droplets. Solvent evaporation obviously changed the flow pattern of droplets. In addition, both droplet behaviors and solvent evaporation reduced the collection efficiency. This study could provide detail information for better understanding the effect of droplet behaviors and solvent evaporation on the particle production process via UAP reactor.


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