Interfacial cross-linking of β-casein changes the structure of the adsorbed layer

Riitta Partanen (Corresponding Author), Pirkko Forssell, Alan Mackie, Eva Blomberg

Research output: Contribution to journalArticleScientificpeer-review

22 Citations (Scopus)

Abstract

The mechanism of transglutaminase-induced cross-linking of interfacial β-casein layer was investigated in tetradecane/buffer system. Monolayer studies were carried out in a Langmuir trough, where incubation with the enzyme mostly affected the compression of the film through adsorption of transglutaminase to the interface. Interfacial shear rheology was used to follow the kinetics of formation of a visco-elastic film upon cross-linking. Substrate concentration affected the rate of the interfacial cross-linking, when enzyme was dosed per protein concentration. This was most likely due to the saturated substrate layer at the interface in all cases. SDS-PAGE revealed that most of the β-casein at the interface was not cross-linked by intermolecular links, but rather, intramolecular links were formed. Finally, studies of adsorbed β-casein layers on polystyrene beads revealed that cross-linking reduced the thickness of the adsorption layer from 11–12 nm to 8–9 nm. These results suggest that it may be mainly intra-molecular cross-linking which modifies the physical interactions of β-caseins at the interface resulting in a higher layer density and thus, formation of a visco-elastic network.
Original languageEnglish
Pages (from-to)271-277
JournalFood Hydrocolloids
Volume32
Issue number2
DOIs
Publication statusPublished - 2013
MoE publication typeA1 Journal article-refereed

Fingerprint

Casein
Caseins
crosslinking
casein
Transglutaminases
protein-glutamine gamma-glutamyltransferase
Adsorption
Enzymes
films (materials)
adsorption
Rheology
Polystyrenes
Substrates
polystyrenes
rheology
Polyacrylamide Gel Electrophoresis
Monolayers
Buffers
enzymes
Compaction

Keywords

  • ß-casein
  • cross-linking
  • interface
  • rheology
  • thickness

Cite this

Partanen, Riitta ; Forssell, Pirkko ; Mackie, Alan ; Blomberg, Eva. / Interfacial cross-linking of β-casein changes the structure of the adsorbed layer. In: Food Hydrocolloids. 2013 ; Vol. 32, No. 2. pp. 271-277.
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Interfacial cross-linking of β-casein changes the structure of the adsorbed layer. / Partanen, Riitta (Corresponding Author); Forssell, Pirkko; Mackie, Alan; Blomberg, Eva.

In: Food Hydrocolloids, Vol. 32, No. 2, 2013, p. 271-277.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Interfacial cross-linking of β-casein changes the structure of the adsorbed layer

AU - Partanen, Riitta

AU - Forssell, Pirkko

AU - Mackie, Alan

AU - Blomberg, Eva

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N2 - The mechanism of transglutaminase-induced cross-linking of interfacial β-casein layer was investigated in tetradecane/buffer system. Monolayer studies were carried out in a Langmuir trough, where incubation with the enzyme mostly affected the compression of the film through adsorption of transglutaminase to the interface. Interfacial shear rheology was used to follow the kinetics of formation of a visco-elastic film upon cross-linking. Substrate concentration affected the rate of the interfacial cross-linking, when enzyme was dosed per protein concentration. This was most likely due to the saturated substrate layer at the interface in all cases. SDS-PAGE revealed that most of the β-casein at the interface was not cross-linked by intermolecular links, but rather, intramolecular links were formed. Finally, studies of adsorbed β-casein layers on polystyrene beads revealed that cross-linking reduced the thickness of the adsorption layer from 11–12 nm to 8–9 nm. These results suggest that it may be mainly intra-molecular cross-linking which modifies the physical interactions of β-caseins at the interface resulting in a higher layer density and thus, formation of a visco-elastic network.

AB - The mechanism of transglutaminase-induced cross-linking of interfacial β-casein layer was investigated in tetradecane/buffer system. Monolayer studies were carried out in a Langmuir trough, where incubation with the enzyme mostly affected the compression of the film through adsorption of transglutaminase to the interface. Interfacial shear rheology was used to follow the kinetics of formation of a visco-elastic film upon cross-linking. Substrate concentration affected the rate of the interfacial cross-linking, when enzyme was dosed per protein concentration. This was most likely due to the saturated substrate layer at the interface in all cases. SDS-PAGE revealed that most of the β-casein at the interface was not cross-linked by intermolecular links, but rather, intramolecular links were formed. Finally, studies of adsorbed β-casein layers on polystyrene beads revealed that cross-linking reduced the thickness of the adsorption layer from 11–12 nm to 8–9 nm. These results suggest that it may be mainly intra-molecular cross-linking which modifies the physical interactions of β-caseins at the interface resulting in a higher layer density and thus, formation of a visco-elastic network.

KW - ß-casein

KW - cross-linking

KW - interface

KW - rheology

KW - thickness

U2 - 10.1016/j.foodhyd.2013.01.009

DO - 10.1016/j.foodhyd.2013.01.009

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