17E-14 |
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C.-S. CHEN and M. H. Penner. Dept. of Food Science & Technology, Oregon State Univ., 100 Wiegand Hall, Corvallis, OR 97331-6602 Studies have been directed toward understanding the effect of temperature and ionic strength (NaCl) on the thermal aggregation of egg white proteins. Ten percent egg white solutions are incubated at various temperatures (50 - 95oC) and ionic strengths (0.0 - 4.0 M NaCl) for 15 or 30 minutes. Total soluble protein is then determined on the resulting suspensions using the Biurett protein assay following centrifugation and supernatant decantation. The solubility behavior of individual proteins is followed by electrophoresis. Denaturation and, where possible, aggregation are followed by differential scanning calorimitry. The majority of the observed effects are due to the predominant protein in egg white, ovalbumin. Relatively low and high ionic strengths both inhibit ovalbumin aggregation. Low ionic strengths appear to inhibit aggregation due to enhanced electrostatic repulsion - thus preventing aggregation of denatured protein. High ionic strengths appear to inhibit aggregation due to ovalbumin stabilization; with some evidence suggesting a conformational change in the protein.
Session 17E, Food Chemistry: Proteins
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