Interfacial and Rheological Properties of Oil-In-Water Emulsions as Affected by Egg Yolk From Different Sources
Hen egg yolk is an essential ingredient for the preparation of a large variety food emulsions, such as mayonnaises, salad dressings and creams. The preparation and long-term stability of this kind of food are influenced by the solution pH. However, the emulsifying properties of duck and goose egg...
| Main Author: | |
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| Format: | Thesis |
| Language: | English English |
| Published: |
2008
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/8514/1/FSTM_2008_13_A%20D.pdf |
| _version_ | 1825944411828125696 |
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| author | Wan Ibadullah, Wan Zunairah |
| author_facet | Wan Ibadullah, Wan Zunairah |
| author_sort | Wan Ibadullah, Wan Zunairah |
| collection | UPM |
| description | Hen egg yolk is an essential ingredient for the preparation of a large variety food
emulsions, such as mayonnaises, salad dressings and creams. The preparation and
long-term stability of this kind of food are influenced by the solution pH. However,
the emulsifying properties of duck and goose egg yolk remain unknown as they have
not been clearly documented. In this study, the emulsion properties (droplet size,
solubility, and viscosity), interface attributes (interfacial protein concentration,
percentage of adsorbed proteins, SDS-Page profiles of adsorbed proteins and
interfacial tension) and rheological properties (thixotropic behavior) of oil-in-water
emulsions prepared with hen, duck and goose egg yolks were examined. These
features were observed at three different pHs (3, 6 and 9). Results showed that pH 6
provided the best conditions for preparing emulsion using the three types of egg
yolks. The droplet size of goose egg yolk emulsions at pH 6 was the smallest than other types of egg yolk at all pH levels. The protein solubility was lower at pH 6 for
all types of egg yolk emulsions. The viscosities of hen, duck and goose egg yolk
emulsions at pH 6 were higher than those at pH 3 and 9. In the pH range studied, the
interface attributes were better at pH 6 for all types of egg yolks. The interfacial
protein concentration was higher at pH 6 for the three types of yolks (1.70 mg m⁻²,
1.74 mg m⁻² and 1.98 mg m⁻², respectively) than at pH 3 and pH 9. At pH 6, most of
the proteins from the three yolks were adsorbed at the interface and the interfacial
tension at steady-state was lower (10 mN m⁻¹, 13.98 mN m⁻¹ and, 8.37 mN m⁻¹
respectively) than at pH 3 or pH 9. At pH 3, proteins at the interface were mainly
phosvitin, and at pH 9, some apoproteins of HDL and LDL were detected. The pH
modulates the composition of yolk proteins at the interface, mainly by modifying the
net charge of the proteins causing their repulsion or dimerization.
The micrographic observation showed that the oil droplets were more uniform at pH
6 than those at pH 3 and 9 for all types of egg yolk emulsions. At pH 6, all of the egg
yolk emulsions exhibited thixotropic shear thinning behavior under steady shear test.
Emulsions produced at pH 3 and 9 exhibited closely the Newtonian behavior. These
results suggested that hen, duck and goose egg yolk are able to provide stabilizing
effects at pH 6. This study shows a good potential for goose and duck egg yolk to be
used as an alternative emulsifying agent in the food industry. |
| first_indexed | 2024-03-06T07:15:27Z |
| format | Thesis |
| id | upm.eprints-8514 |
| institution | Universiti Putra Malaysia |
| language | English English |
| last_indexed | 2024-03-06T07:15:27Z |
| publishDate | 2008 |
| record_format | dspace |
| spelling | upm.eprints-85142022-01-26T04:15:25Z http://psasir.upm.edu.my/id/eprint/8514/ Interfacial and Rheological Properties of Oil-In-Water Emulsions as Affected by Egg Yolk From Different Sources Wan Ibadullah, Wan Zunairah Hen egg yolk is an essential ingredient for the preparation of a large variety food emulsions, such as mayonnaises, salad dressings and creams. The preparation and long-term stability of this kind of food are influenced by the solution pH. However, the emulsifying properties of duck and goose egg yolk remain unknown as they have not been clearly documented. In this study, the emulsion properties (droplet size, solubility, and viscosity), interface attributes (interfacial protein concentration, percentage of adsorbed proteins, SDS-Page profiles of adsorbed proteins and interfacial tension) and rheological properties (thixotropic behavior) of oil-in-water emulsions prepared with hen, duck and goose egg yolks were examined. These features were observed at three different pHs (3, 6 and 9). Results showed that pH 6 provided the best conditions for preparing emulsion using the three types of egg yolks. The droplet size of goose egg yolk emulsions at pH 6 was the smallest than other types of egg yolk at all pH levels. The protein solubility was lower at pH 6 for all types of egg yolk emulsions. The viscosities of hen, duck and goose egg yolk emulsions at pH 6 were higher than those at pH 3 and 9. In the pH range studied, the interface attributes were better at pH 6 for all types of egg yolks. The interfacial protein concentration was higher at pH 6 for the three types of yolks (1.70 mg m⁻², 1.74 mg m⁻² and 1.98 mg m⁻², respectively) than at pH 3 and pH 9. At pH 6, most of the proteins from the three yolks were adsorbed at the interface and the interfacial tension at steady-state was lower (10 mN m⁻¹, 13.98 mN m⁻¹ and, 8.37 mN m⁻¹ respectively) than at pH 3 or pH 9. At pH 3, proteins at the interface were mainly phosvitin, and at pH 9, some apoproteins of HDL and LDL were detected. The pH modulates the composition of yolk proteins at the interface, mainly by modifying the net charge of the proteins causing their repulsion or dimerization. The micrographic observation showed that the oil droplets were more uniform at pH 6 than those at pH 3 and 9 for all types of egg yolk emulsions. At pH 6, all of the egg yolk emulsions exhibited thixotropic shear thinning behavior under steady shear test. Emulsions produced at pH 3 and 9 exhibited closely the Newtonian behavior. These results suggested that hen, duck and goose egg yolk are able to provide stabilizing effects at pH 6. This study shows a good potential for goose and duck egg yolk to be used as an alternative emulsifying agent in the food industry. 2008 Thesis NonPeerReviewed text en http://psasir.upm.edu.my/id/eprint/8514/1/FSTM_2008_13_A%20D.pdf Wan Ibadullah, Wan Zunairah (2008) Interfacial and Rheological Properties of Oil-In-Water Emulsions as Affected by Egg Yolk From Different Sources. Masters thesis, Universiti Putra Malaysia. Emulsions - Case studies English |
| spellingShingle | Emulsions - Case studies Wan Ibadullah, Wan Zunairah Interfacial and Rheological Properties of Oil-In-Water Emulsions as Affected by Egg Yolk From Different Sources |
| title | Interfacial and Rheological Properties of Oil-In-Water Emulsions as Affected by Egg Yolk From Different Sources |
| title_full | Interfacial and Rheological Properties of Oil-In-Water Emulsions as Affected by Egg Yolk From Different Sources |
| title_fullStr | Interfacial and Rheological Properties of Oil-In-Water Emulsions as Affected by Egg Yolk From Different Sources |
| title_full_unstemmed | Interfacial and Rheological Properties of Oil-In-Water Emulsions as Affected by Egg Yolk From Different Sources |
| title_short | Interfacial and Rheological Properties of Oil-In-Water Emulsions as Affected by Egg Yolk From Different Sources |
| title_sort | interfacial and rheological properties of oil in water emulsions as affected by egg yolk from different sources |
| topic | Emulsions - Case studies |
| url | http://psasir.upm.edu.my/id/eprint/8514/1/FSTM_2008_13_A%20D.pdf |
| work_keys_str_mv | AT wanibadullahwanzunairah interfacialandrheologicalpropertiesofoilinwateremulsionsasaffectedbyeggyolkfromdifferentsources |