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MOLECULAR DESCRIPTION OF AGGREGATION, DENATURATION, GELATION AND SURFACE ACTIVITY OF WHEY PROTEINS

Objective

The principal objective of this concerted action is to make a concerted effort to gain fundamental knowledge about the behaviour of whey proteins, relevant to improving methods of recovering them from whey and giving them added value as food ingredients in the growing market for functional and probiotic foods.

To do this, we will apply a range of modern analytical, physical and theoretical methods to whey protein aggregation, gelation, denaturation and surface adsorption phenomena and interpret the results using the growing body of molecular structural information. To ensure comparability of results and a high degree of concertation, specially prepared whey protein samples will be distributed for use throughout the concerted action.

Specific objectives are :

To extend X-ray crystal structure determination on B-lactoglobulin in ways relevant to food applications. To develop an expression system for B-lactoglobulin and carry out site directed mutagenesis with the aim of explaining the large difference in surface activity between the A and B variants. To study the Tanford transition in solution by spectroscopic and scattering methods and use the X-ray crystal structure data to help interpret the results. To study the heat-induced aggregation of B-lactoglobulin above the Tanford-like transition temperature by static and dynamic scattering measurements. Use the structural information on the monomer and its conformational changes to interpret the structure (size, stiffness, branching, etc.) of the polymer chains and their rate of formation. To characterise whey protein gels by rheometry and relate their viscoelastic properties to the molecular structure of the polymer chains and the mechanisms of polymerisation. To study the thermal denaturation of whey proteins at concentrations and temperatures relevant to processing conditions, with and without bound lipids, using the new range of high sensitivity calorimeters. To study the adsorption of whey protein fractions and isolates at interfaces. The molecular basis of the difference in surface adsorption of B-lactoglobulins A and B will be explored through recombinant proteins. To study the effect of lipid phase structure and composition on the interaction with whey protein fractions and isolates adsorbed at interfaces so that we can understand factors controlling foaming and emulsification and the role of proteins in fat-rich environments and as fat replacers in low-fat foods.

Coordinator

HANNAH RESEARCH INSTITUTE
Address

KA6 5HL Ayr
United Kingdom

Participants (6)

I.N.R.A.
France
Address
Rue De Saint-brieuc, 65
35042 Rennes
NIZO - NEDERLANDS INSTITUUT VOOR ZUIVELONDERZOEK, NV
Netherlands
Address
Kernhemseweg, 2
6710 BA Ede
ROYAL VETERINARY AND AGRICULTURAL UNIVERSITY
Denmark
Address
Thorvaldsensvej, 40
1871 Frederiksberg C
UNIVERSIDAD DE ZARAGOZA
Spain
Address
Plaza De San Francisco
50013 Zaragoza
UNIVERSITY OF LUND
Sweden
Address
Getingevägen, 60 - P.o. Box 117
221 00 Lund
University of Edinburgh
United Kingdom
Address
George Square
EH8 9XD Edinburgh