Title
Modification of β-lactoglobulin by oligofructose: Impact on protein adsorption at the air-water interface
Author
Trofimova, D.
de Jongh, H.H.J.
TNO Voeding
Publication year
2004
Abstract
Maillard products of β-lactoglobulin (βLg) and fructose oligosaccharide (FOS) were obtained in different degrees of modification depending on incubation time and pH. By use of a variety of biochemical and spectroscopic tools, it was demonstrated that the modification at limited degrees does not significantly affect the secondary, tertiary, and quaternary structure of βLg. The consequence of the modification on the thermodynamics of the protein was studied using differential scanning calorimetry, circular dichroism, and by monitoring the fluorescence intensity of protein samples with different concentrations of guanidine-HCl. The modification leads to lowering of the denaturation temperature by 5°C and a reduction of the free energy of stabilization of about 30%, Ellipsometry and drop tensiometry demonstrated that upon adsorption to air-water interfaces in equilibrium modified βLg exerts a lower surface pressure than native βLg (16 versus 22 mN/m). Moreover, the surface elastic modulus increased with increasing surface pressure but reached significantly smaller values in the case of FOS-βLg. Compared to native βLg, modification of the protein with oligofructose moieties results in higher surface loads and thicker surface layers. The consequences of these altered surface rheological properties are discussed in view of the functional behavior in technological applications.
Subject
Nutrition
Food technology
Adsorption
Chemical modification
Contacts (fluid mechanics)
Differential scanning calorimetry
Elastic moduli
Fluorescence
Proteins
β-lactoglobulin
Drop tensiometry
Oligofructose
Fructose
Adsorption
Calorimetry
Circular Dichroism
Elastic Strength
Fluorescence
Fructose
Globulins
Oligosaccharides
Proteins
lactoglobulin
oligofructose
oligosaccharide
water
adsorption
air
article
chemistry
elasticity
ion exchange chromatography
metabolism
pH
phase transition
protein folding
protein secondary structure
spectroscopy
thermodynamics
time
viscosity
Adsorption
Air
Chromatography, Ion Exchange
Elasticity
Hydrogen-Ion Concentration
Lactoglobulins
Oligosaccharides
Phase Transition
Protein Folding
Protein Structure, Secondary
Spectrum Analysis
Thermodynamics
Time Factors
Viscosity
Water
To reference this document use:
http://resolver.tudelft.nl/uuid:739ed037-ee0e-4deb-b5f8-d1e81c703bc7
DOI
https://doi.org/10.1021/la049390j
TNO identifier
237845
ISSN
0743-7463
Source
Langmuir, 20 (13), 5544-5552
Document type
article