Assessment of Rheological Behaviour of Water-in-Oil Emulsions Mediated by Glycolipid Biosurfactant Produced by Bacillus megaterium SPSW1001

2021 ◽  
Author(s):  
Varsha Singh ◽  
Zairah Waris ◽  
Ibrahim M. Banat ◽  
Sriparna Saha ◽  
Padmini Padmanabhan
Keyword(s):  
Bacillus Megaterium ◽  
Rheological Behaviour ◽  
Glycolipid Biosurfactant ◽  
Oil Emulsions

scholarly journals Rheological properties and flow behaviour of wax-stabilized water-in-oil emulsions

2021 ◽  
Author(s):  
Samira Haj-Shafiei
Keyword(s):  
Rheological Properties ◽  
Initial Temperature ◽  
Rheological Behaviour ◽  
Flow Behaviour ◽  
Paraffin Wax ◽  
Oscillatory Rheology ◽  
Initial Deposition ◽  
Oil Emulsions ◽  
Light Mineral ◽  
Glycerol Monooleate

The objective of this study was to characterize the flow and rheological behaviour of model wax-stabilized water-in-oil (W/O) emulsions consisting of light mineral oil, paraffin wax and glycerol monooleate as the oil phase and water as the dispersed aqueous phase. An[sic] laboratory-scale benchtop flowloop system was used to explore the flow behaviour of the emulsions' oil phase (oil, paraffin wax and surfactant). The key contribution from this work was that the higher initial temperature gradient (40°C compared to 19°C) experienced by the rapidly-cooled oil led to more initial deposition on the flowloop inner wall. The rheological properties of W/O emulsions with different water cuts (10-50wt%) were also studied. Rotational, oscillatory rheology and creep compliance and recovery were characterized on emulsions aged up to 28 days. Overall, the results demonstrated that emulsion composition, and age could significantly influence an emulsion's flow behaviour and rheological properties.

scholarly journals Rheological properties and flow behaviour of wax-stabilized water-in-oil emulsions

2021 ◽  
Author(s):  
Samira Haj-Shafiei
Keyword(s):  
Rheological Properties ◽  
Initial Temperature ◽  
Rheological Behaviour ◽  
Flow Behaviour ◽  
Paraffin Wax ◽  
Oscillatory Rheology ◽  
Initial Deposition ◽  
Oil Emulsions ◽  
Light Mineral ◽  
Glycerol Monooleate

The objective of this study was to characterize the flow and rheological behaviour of model wax-stabilized water-in-oil (W/O) emulsions consisting of light mineral oil, paraffin wax and glycerol monooleate as the oil phase and water as the dispersed aqueous phase. An[sic] laboratory-scale benchtop flowloop system was used to explore the flow behaviour of the emulsions' oil phase (oil, paraffin wax and surfactant). The key contribution from this work was that the higher initial temperature gradient (40°C compared to 19°C) experienced by the rapidly-cooled oil led to more initial deposition on the flowloop inner wall. The rheological properties of W/O emulsions with different water cuts (10-50wt%) were also studied. Rotational, oscillatory rheology and creep compliance and recovery were characterized on emulsions aged up to 28 days. Overall, the results demonstrated that emulsion composition, and age could significantly influence an emulsion's flow behaviour and rheological properties.

scholarly journals Flow behaviour of water-in-oil emulsions stabilized by wax crystals

2021 ◽  
Author(s):  
Roomana Aafaqi
Keyword(s):  
Crude Oil ◽  
Pipe Wall ◽  
Rheological Behaviour ◽  
Flow Behaviour ◽  
Large Temperature ◽  
Gelation Temperature ◽  
Emulsion Flow ◽  
Oil Emulsions ◽  
Polyglycerol Polyricinoleate ◽  
Wax Crystals

The large temperature gradients experienced by crude oil emulsions in pipelines found in colder environments can lead to the precipitation, deposition and build-up of wax-like species from the crude oil onto the pipe wall that result in flow assurance problems. The objective of this thesis was to understand the rheological behaviour of model water-in-oil emulsions stabilized by wax crystals. The microstructure, phase transitions and rheology of model emulsions constisting of water, mineral oil, parrafin wax and the emulsifier polyglycerol polyricinoleate (PgPr) were investigated. Changes in emulsion flow begaviour (steady state and dynamic) as a function of composition, termperature and passage through a laboratory-scale flowloop were investigated, with these parameters significantly affecting shear flow, yield stress and viscoelasticity. The gelation temperature of wax-containing ('waxy') oil was slightly lower than that of its equivalent emulsion due to differences in the structure of the gelled emulsion network. Overall, this study successfully showed that there exist significant differences in the microstructure and flow behaviour of model crude oil emulsions when wax and a dispersed aqueous phase are present.

scholarly journals Flow behaviour of water-in-oil emulsions stabilized by wax crystals

2021 ◽  
Author(s):  
Roomana Aafaqi
Keyword(s):  
Crude Oil ◽  
Pipe Wall ◽  
Rheological Behaviour ◽  
Flow Behaviour ◽  
Large Temperature ◽  
Gelation Temperature ◽  
Emulsion Flow ◽  
Oil Emulsions ◽  
Polyglycerol Polyricinoleate ◽  
Wax Crystals

The large temperature gradients experienced by crude oil emulsions in pipelines found in colder environments can lead to the precipitation, deposition and build-up of wax-like species from the crude oil onto the pipe wall that result in flow assurance problems. The objective of this thesis was to understand the rheological behaviour of model water-in-oil emulsions stabilized by wax crystals. The microstructure, phase transitions and rheology of model emulsions constisting of water, mineral oil, parrafin wax and the emulsifier polyglycerol polyricinoleate (PgPr) were investigated. Changes in emulsion flow begaviour (steady state and dynamic) as a function of composition, termperature and passage through a laboratory-scale flowloop were investigated, with these parameters significantly affecting shear flow, yield stress and viscoelasticity. The gelation temperature of wax-containing ('waxy') oil was slightly lower than that of its equivalent emulsion due to differences in the structure of the gelled emulsion network. Overall, this study successfully showed that there exist significant differences in the microstructure and flow behaviour of model crude oil emulsions when wax and a dispersed aqueous phase are present.

scholarly journals Development of Gel-in-Oil Emulsions for Khellin Topical Delivery

Pharmaceutics ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 398
Author(s):  
Joana Pereira ◽  
Rita Gonçalves ◽  
Margarida Barreto ◽  
Clarisse Dias ◽  
Fátima Carvalho ◽  
...  
Keyword(s):  
Droplet Size ◽  
Rheological Behaviour ◽  
In Vitro Studies ◽  
Solar Irradiation ◽  
Colored Complex ◽  
Promising Alternative ◽  
Macroscopic Appearance ◽  
Topical Gel ◽  
Oil Emulsions

Hypopigmentation is a progressive dermatological condition caused by a reduction in the skin pigment, melanin. Its treatment is considered a challenge due to the lack of a highly efficient single therapy. Currently, the main treatments include photochemotherapy, application of corticosteroids and immunosuppressants, and laser. Khellin-based gel-in-oil emulsions appear as a promising alternative since they ensure a concentration of the drug, a natural furanochromone, at the desired location, skin surface. Khellin promotes repigmentation as it forms a dark colored complex after solar irradiation. The aim of this study was the development and characterization (e.g., rheological behaviour, droplet size, tackiness, adhesion and spreadability) of three topical gel-in-oil emulsions prepared with different emollients, formulated through a cold emulsification process, and suitable for the incorporation of khellin. In vitro studies were performed to evaluate the drug release and permeation profiles across artificial membranes and excised human skin, respectively, using Franz-type vertical diffusion cells. The W/O emulsions developed showed macroscopic appearance, shear-thinning behavior with a mean droplet size from 3.28 to 4.28 μm, suitable for topical application. In vitro studies revealed permeation values of about 1% of khellin across the stratum corneum, making these gel-in-oil emulsions promising for preclinical and clinical studies. The cold process, being an easy and low energy production method, represents an innovative strategy to produce khellin-based gel-in-oil emulsions to treat patients with hypopigmentation.

scholarly journals Buriti Oil Emulsions as Affected by Soy Protein Isolate/High-Methoxyl Pectin Ratio, Oil Content and Homogenization Pressure

2020 ◽  
Vol 58 (2) ◽  
pp. 159-172
Author(s):  
Mírian Luisa Faria Freitas ◽  
Ana Paula Badan Ribeiro ◽  
Vânia Regina Nicoletti
Keyword(s):  
Electrical Conductivity ◽  
Droplet Size ◽  
Soy Protein ◽  
Oil Content ◽  
Soy Protein Isolate ◽  
Rheological Behaviour ◽  
Continuous Phase ◽  
Protein Isolate ◽  
Buriti Oil ◽  
Oil Emulsions

Research background. Emulsion technology is a suitable way of encapsulating, protecting and releasing hydrophobic bioactive compounds for application in food industries, but they are thermodynamically unstable systems. Good results have been achieved for emulsions stabilized by protein-polysaccharide complexes subjected to high-pressure homogenization. Improved stabilization of oil-in-water emulsions results from electrostatic complexes formed between proteins and polysaccharides at pH lower than the protein isoelectric point, which adsorb at the oil-water interface. In addition, polysaccharides contribute to emulsion stability by increasing viscosity of the continuous phase. The aim of this work is to investigate the production of carotenoid-rich buriti oil emulsions using soy protein isolate and high-methoxyl pectin as stabilizers. Experimental approach. Using a rotatable central composite experimental design, we assessed the effects of oil content, soy protein isolate/high-methoxyl pectin ratio and homogenization pressure on the stability, droplet size, electrical conductivity, electrical charge, microstructure and rheological behaviour of the emulsions. Results and conclusions. An optimized emulsion was produced with 28 % buriti oil, 55 % soy protein isolate, and homogenization pressure of 380·105 Pa. This emulsion was stable for at least seven days, presenting reduced average droplet size, low electrical conductivity and high modulus of negative charges. The mechanical spectra showed that the emulsion behaved as a viscoelastic gel under oscillatory, non-destructive shearing, whereas shearthinning behaviour took place under steady shear conditions. Novelty and scientific contribution. The optimized buriti oil emulsions stabilized by soy protein isolate and high-methoxyl pectin could be suitable for fat substitution, energy reduction and carotenoid enrichment in food products, such as dairy and bakery products, ice cream, salad sauces and vegetable-based cream.

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