Title
Acid-Induced Cold Gelation of Globular Proteins: Effects of Protein Aggregate Characteristics and Disulfide Bonding on Rheological Properties
Author
Alting, A.C.
Weijers, M.
de Hoog, E.H.A.
van de Pijpekamp, A.M.
Cohen Stuart, M.A.
Hamer, R.J.
de Kruif, C.G.
Visschers, R.W.
TNO Voeding
Publication year
2004
Abstract
The process of cold gelation of ovalbumin and the properties of the resulting cold-set gels were compared to those of whey protein isolate. Under the chosen heating conditions, most protein was organized in aggregates. For both protein preparations, the aggregates consisted of covalently linked monomers. Both types of protein aggregates had comparable numbers of thiol groups exposed at their surfaces but had clearly different shapes. During acid-induced gelation, the characteristic ordering caused by the repulsive character disappeared and was replaced by a random distribution. This process did not depend on aggregate characteristics and probably applies to any type of protein aggregate. Covalent bonds are the main determinants of the gel hardness. The formation of additional disulfide bonds during gelation depended on the number and accessibility of thiol groups and disulfide bonds in the molecule and was found to clearly differ between the proteins studied. However, upon blocking of the thiol groups, long fibrillar structures of ovalbumin contribute significantly to gel hardness, demonstrating the importance of aggregate shape.
Subject
Nutrition
Food technology
Aggregation
Cold gelation
Fibril formation
Ordered structures
Ovalbumin
Thiol-disulfide exchange reaction
Whey protein isolate
acid
cross linking reagent
Cross Linking Reagents
disulfide
globular protein
milk protein
monomer
ovalbumin
thiol derivative
thiol group
whey protein
article
chemistry
cold
covalent bond
disulfide bond
electron microscopy
fiber
flow kinetics
gel
gelation
hardness
heat treatment
pH
protein aggregation
protein isolation
randomization
whey
Cold
Cross-Linking Reagents
Disulfides
Gels
Hydrogen-Ion Concentration
Microscopy, Electron
Milk Proteins
Ovalbumin
Rheology
Sulfhydryl Compounds
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TNO identifier
237619
ISSN
0021-8561
Source
Journal of Agricultural and Food Chemistry, 52 (3), 623-631
Document type
article