FOOD 2400 Study Guide - Final Guide: Clathrate Hydrate, Sorption, Desorption
2 Dec 2018
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Document Summary
High specific heat large density differences between water and ice. High melting and boiling temperature, surface tension, capillary action, high heat of transition. Moderately low density, expands upon solidification (ice). Freezes more rapidly than thaws (thermal conductivity and diffusivities) Bound water refers to water which is very tightly/closely associated with molecular structures. composition, ph and temp. Water binding/hydration depends on substances hydrophilic nature, considering salt. Water holding capacity e. g. , gels of pectin and starch, water in cells - syneresis. Clathrate hydrates ice-like structures where water (the host) physically entraps low molecular weight compounds known as guests (e. g. , hydrocarbons, rare gases, carbon dioxide, sulphur dioxide). Water activity is the relationship between water content and perishability. Not the same as water content, simply the amount of water that is available to participate in reactions and for microbial growth. Aw 1. 0 = roughly 50% water content. Sorption isotherms is a plot of aw and water content.
