FOOD 2010 Chapter Notes - Chapter 4: Glass Transition, Water Activity, Amphiphile
13 Nov 2012
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Document Summary
Food molecules can form h-bonds with water meaning that they can be dispersed or dissolved. Hydration is process by which water molecules surround and interact with solutes by acting as a solvent. Can disperce amphiphilic agents (part hydroscopic, part hydrophobic) Moisture: amount of water present in a food relative to all the solid constituents and non- water liquids. Free water: lightly entrapped, so easily pressed from food matter. Absorbed water: associates by layers via intermolecular h-bonds around hydrophilic food. Bound water: (water of hydration) tight chemically bound situations [ in crystalline structure] Aw: measure of the availability of water molecules to enter into microbial, enzymatic, or chemical reactions. 4. 4 the chemical and functional properties of water. Thus emulsifier is needed if need to have 1 continuous phase. Important vehicle for heat transfer in foods during processing and preparation. Water acts as a conductor of thermal energy to food molecules, process = heat transfer.
