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Do sulfhydryl groups affect aggregation and gelation properties of ovalbumin?

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Author: Broersen, K. · Teeffelen, A.M.M. van · Vries, A. · Voragen, A.G.J. · Hamer, R.J. · Jongh, H.H.J. de
Type:article
Date:2006
Institution: TNO Kwaliteit van Leven
Source:Journal of Agricultural and Food Chemistry, 14, 54, 5166-5174
Identifier: 239369
doi: doi:10.1021/jf0601923
Keywords: Nutrition · Food technology · Aggregation · Cryo-TEM · Disulfide bonds · Gel properties · Large and small deformation rheology · Ovalbumin · Sulfhydryl groups · disulfide · ovalbumin · thiol derivative · article · chemistry · electron microscopy · flow kinetics · gel · kinetics · physical chemistry · polyacrylamide gel electrophoresis · Chemistry, Physical · Disulfides · Electrophoresis, Polyacrylamide Gel · Gels · Kinetics · Microscopy, Electron · Ovalbumin · Rheology · Sulfhydryl Compounds

Abstract

The aim of this work is to evaluate the impact of sulfhydryl groups on ovalbumin aggregation and gelation. Ovalbumin was chemically modified to add sulfhydryl groups in various degrees. The rate of aggregation was not affected by the introduction of sulfhydryl groups, and disulfide bond formation was preceded by physical interactions. Hence, disulfide interactions may not be the driving force for the aggregation of ovalbumin. Investigation of the aggregates and gels by electron microscopy and rheology suggested that a critical number of sulfhydryl groups can be introduced beyond which the microstructure of the aggregates transforms from fibrillar into amorphous. Rheological studies further suggested that covalent networks, once formed, do not have the possibility to rearrange, reducing the possibility to attain a stronger network. These results show that, even though aggregation of ovalbumin may be primarily driven by physical interactions, formed disulfide bonds are important to determine the resulting aggregate morphology and rheological properties. © 2006 American Chemical Society.