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Thermostabilization of ovalbumin in a developing egg by an alkalinity-regulated, two-step process
H Hatta1, M Nomura, N Takahashi
1Department of Food and Nutrition, Kyoto Women's University, Japan.
Bioscience, Biotechnology, and Biochemistry
|October 26, 2001
Summary
The conversion of ovalbumin to heat-stable S-ovalbumin is slower in fertile eggs than unfertile ones. This difference is attributed to the alkalinity of egg white during incubation.
Area of Science:
- Biochemistry
- Food Science
- Avian Biology
Background:
- Ovalbumin naturally converts to a heat-stable form, S-ovalbumin, in eggs and solutions.
- Recent studies indicated this conversion also occurs in fertile eggs.
Purpose of the Study:
- To investigate the rate of ovalbumin conversion to S-ovalbumin in fertile versus unfertile avian eggs.
- To determine the factors influencing the differential conversion rates observed between fertile and unfertile eggs.
Main Methods:
- Calorimetric analysis of ovalbumin samples isolated from fertile and unfertile eggs.
- Monitoring and simulating pH changes in egg white during incubation.
- Comparing ovalbumin conversion rates under controlled pH conditions.
Main Results:
- Ovalbumin conversion to S-ovalbumin was significantly slower in fertile eggs compared to unfertile eggs under identical incubation.
- Distinct pH changes were observed in the egg white of fertile and unfertile eggs during incubation.
- Manually adjusting purified ovalbumin pH to mimic egg white changes replicated the observed conversion rates.
Conclusions:
- The thermostabilization of ovalbumin in fertile eggs is influenced by a mechanism dependent on egg white alkalinity.
- Egg white pH plays a crucial role in regulating the rate of ovalbumin conversion to its heat-stable form.
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