Protein Hydration in Structure Creation
Kapitel i bok, 2010

Food processors have made structures from natural biopolymers for centuries, so why do we still not know the answers to all the problems of structure design, and its creation, in foods? Proteins are heteropolymers of amino acids, not designed for fabrication by processors, but evolved for particular biological functions at ambient temperature. Their performance derives from their distinctive native structure and that structure ' s peculiar interaction with its aqueous environment. We are left to elucidate their behavior under more extreme conditions of pH, water activity (a w ), temperature, pressure, etc. Adsorption isotherms of water on proteins at least show some similarities, and food processing operates across the entire a w or moisture - content spectrum. This report reviews what we know relative to the operating conditions and water contents used, with reference to general rules and the inevitable exceptions.

Resultant phase composition - relative compatibility of each solute with water

Permeability measurements - made of coarsely aggregated dairy gels

Gelation of proteins - determination by competition between kinetics of denaturation and aggregation

Denaturation - cooperative phenomenon routinely and easily measured

Adsorption - thermodynamic equilibrium line

Key parameter measured for proteins - water-holding capacity

Expanded solid foams - components of breakfast cereals and snacks

Protein hydration - structure creation


P.J. Lillford

University of Birmingham

Anne-Marie Hermansson

Chalmers, Kemi- och bioteknik, Teknisk ytkemi

Water Properties in Food, Health, Pharmaceutical and Biological Systems: ISOPOW 10