Title
The presence of heat-stable conformers of ovalbumin affects properties of thermally formed aggregates
Author
de Groot, J.
de Jongh, H.H.J.
TNO Voeding
Publication year
2003
Abstract
The aim of this work was to study the effect of the formation of more heat-stable conformers of chicken egg ovalbumin during incubation at basic pH (9.9) and elevated temperature (55°C) on the protein aggregation properties at neutral pH. Native ovalbumin (N-OVA) is converted on the hours time-scale into more heat-stable forms denoted I- (intermediate) and S-OVA, that have denaturation temperatures 4.8 and 8.4°C, respectively, higher than that of N-OVA. The conversions most likely proceed via I-OVA, but direct conversion of N-OVA into S-OVA with slower kinetics can not be excluded. It is demonstrated that both I- and S-OVA have similar denaturation characteristics to N-OVA, except that higher temperatures are required for denaturation. The presence of even small contributions of I-OVA does, however, reduce the Stokes radius of the aggregates formed upon heat treatment of the material at 90°C about 2-fold. This affects the gel network formation considerably. Since many (commercial) preparations of ovalbumin contain varying contributions of the more heat-stable forms mentioned, proper characterization or standardization of the isolation procedure of the material is essential to control or predict the industrial application of this protein. Chemicals/CAS: ovalbumin, 77466-29-6; Ovalbumin, 9006-59-1
Subject
Nutrition
Food technology
Aggregation
Ovalbumin
Protein denaturation
Stokes radius
Turbidity
ovalbumin
article
chemical reaction kinetics
heat treatment
pH
priority journal
protein aggregation
protein analysis
protein denaturation
protein stability
thermostability
turbidity
Animals
Calorimetry, Differential Scanning
Chickens
Heat
Kinetics
Ovalbumin
Protein Conformation
Time Factors
Gallus gallus
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TNO identifier
237473
ISSN
0269-2139
Source
Protein Engineering, 16 (12), 1035-1040
Document type
article