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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Production of emulsifier by Torulopsis petrophilum

Rizzi, John January 1987 (has links)
No description available.
92

Identification and characterisation of mannoprotein emulsifier from Baker's yeast

Cameron, David R. (David Robert) January 1992 (has links)
The mannoprotein of Saccharomyces cerevisiae, baker's yeast, is an emulsifying agent which could be used in foods and cosmetics. This glycoprotein emulsifier can be extracted simply with very good yield by autoclaving yeast cells in neutral buffer. The spent yeast from the beer and wine industries is a suitable raw material for its production. Protein detected by binding of Coomassie blue dye was essential for emulsifying activity. Components of the heat extracted material with greatest emulsifying activity included a high molecular weight fraction ($>$200 kDa) which provided viscous and durable emulsions, and a low molecular weight fraction ($<$14 kDA) which was very surface active and readily generated nonviscous emulsions. Mannoprotein and the small molecule surfactants lecithin and cetyltrimethylammonium bromide interacted synergistically to increase emulsifying activity at a weight ratio of 100:1 mannoprotein to surfactant. A correction was made to the formula for the Emulsifying Activity Index (Pearce, K. N. and J. E. Kinsella. 1978. J. Agric. Food Chem. 26:716-723), a measure commonly used for comparing protein emulsifiers.
93

Rheology and stability of beverage emulsions in concentrated and diluted forms

Taherian, Ali Reza. January 2006 (has links)
Consumer's demand for more natural and high quality food products products, presenting health benefits, has increased over the years. Besides the nutritional aspects, an appealing appearance and texture is also required. Cloudiness or opacity (cloudy appearance) is an important citrus drinks property (orange, lime, lemon, etc.), since it gives natural fruit juice appeal. This property can be achieved through addition of clouding agents, which also help in uniform distribution of flavors throughout the liquid beverage. A common problem in the beverage industry is producing cloud or flavor emulsions that remain stable over the desired shelf life. Beverage cloud emulsions are oil-in-water emulsions to provide cloudiness and are prepared in a concentrated form, but diluted prior to the consumption. / Optical and rheological properties of beverage cloud emulsions as a function of water-phase and oil-phase concentrations were investigated. The specific gravity of phases, particle size distribution and creaming stability of prepared emulsions in diluted forms were evaluated. The rate of cloud emulsion creaming by determining the rheology of water phase, difference in specific gravities of the phases and droplet properties of the emulsion in presence and absence of weighting agents (sucrose acetate isobutyrate and brominated vegetable oil) or/and xanthan gum was studied. Flow and dynamic rheological properties of single-phases and emulsions containing modified starch and arabic gum as surface active hydrocolloids as well as xanthan and tragacanth as stabilizers gums were investigated. Finally, stability of cloud emulsions in orange juice drink was examined. / Oil-phase concentration had a significant effect (P < 0.05) on increasing the opacity of emulsion. Raise in viscosity of emulsions was more pronounced as oil concentration increased and shear thinning behavior of oil added emulsions was associated with droplet flocculation. Creaming in acidified sugar solution of 11°Bx and pH 3 was observed when the oil-phase specific gravity decreased and sedimentation occurred at the lower viscosity of water phase. Addition of xanthan gum into the water phase decreased the flow behavior index (n) form 0.88 down to 0.31 and increased elastic modulus (G') over 20 times at elevated frequency (o = 50 rad/s) and perk up the stability of the emulsion. / The xanthan gum added emulsion indicated smaller average particle size and demonstrated 14 and 5 times slower separation compared to the emulsions without or with the addition of weighting agents respectively. Starch-xanthan stabilized emulsion and associated water phase at 1.5:1 surface active gum to oil ratio demonstrated viscoelastic behavior (G' ≥ G") with lower droplets coalescence and creaming rates, 0.013 nm/day and 0.02 percent backscattering/day respectively. Conversely, arabic-xanthan stabilized emulsion at 1:1 gum to oil ratio showed the highest rate of droplets coalescence at 0.057 rim/day and greater degree of creaming at 0.61 percent transmission/day. While creaming were associated with arabic gum stabilized emulsions, after 3 month storage, modified starch illustrated appropriate shelf stability with no sign of creaming in orange juice drink.
94

Emulsion droplets of controlled deformability :

Barnes, Timothy J Unknown Date (has links)
This study has highlighted the role of emulsion droplet cross-linking (deformability and penetrability) on droplet surface chemistry, droplet colloidal stability and adsorption at the droplet-water interface and provides insight into methods for enhancing the performance of emulsion formulations. / Thesis (PhD)--University of South Australia, 2003.
95

Emulsion droplets of controlled deformability: electrokinetics, colloid stability and polymer adsorption

Barnes, Timothy J January 2003 (has links)
This study has highlighted the role of emulsion droplet cross-linking (deformability and penetrability) on droplet surface chemistry, droplet colloidal stability and adsorption at the droplet-water interface and provides insight into methods for enhancing the performance of emulsion formulations.
96

Emulsion droplets of controlled deformability :

Barnes, Timothy J Unknown Date (has links)
This study has highlighted the role of emulsion droplet cross-linking (deformability and penetrability) on droplet surface chemistry, droplet colloidal stability and adsorption at the droplet-water interface and provides insight into methods for enhancing the performance of emulsion formulations. / Thesis (PhD)--University of South Australia, 2003.
97

Light scattering study of attractive interactions in a model microemulsion system /

Campbell, Dawn M. January 1992 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 19xx. / Includes bibliographical references.
98

Heavy oil tar emulsions in the water gas process

Stolzenbach, Charles Frederick, January 1934 (has links)
Thesis (Ph. D.)--Columbia University, 1934. / Vita. Bibliography: p. 20.
99

Effect of high shearing on the rheological/structural properties of highly concentrated w/o emulsions

Yakhoub, Hamat Abderrahmane January 2009 (has links)
Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2009. / Emulsion explosives are classified as highly concentrated water-in-oil emulsions with high droplet volume fraction that exceeding the close packing limit of spherical droplets. These emulsions are commonly used as re-pumpable materials. Thus, the shearing action resulting from the transportation process of these materials has a tremendous impact on their structures and functionality and might reduce the shelf-life and performance of the products. Therefore the main goal of this research was to investigate the stability of highly concentrated water-in-oil emulsion under shearing using a newly designed piston-pumping instrument. The results of measurement included the droplet size distribution, microscopic observation, flow and viscoelastic properties of the materials. Neither crystallisation nor other destabilisation phenomena such as coalescence, partial coalescence, or phase inversion occurred during the shearing process of these emulsions, regardless of their formulation content. It was found that the high shearing action within this research experimental window induced droplet refinement. The changes in droplet size distribution were achieved by multipass flow through a small orifice set as outlet of the piston-chamber pumping instrument, and intensive shearing provided the shift of the droplet sizes to the smaller-size side of the distribution. Their distributions were wider and of Gaussian type. Two models were proposed and used to fit the refinement evolution and the width of distributions respectively.
100

Rheology and stability of beverage emulsions in concentrated and diluted forms

Taherian, Ali Reza. January 2006 (has links)
No description available.

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