NUTR 214 Lecture Notes - Lecture 11: Yolk, Salad, Polysaccharide
15 Oct 2016
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Document Summary
Dispersion systems: classification according to the size of the dispersed particles. True solutions (< 1nm) ---small size, stable. Small molecules or ions, such as sugars, salts, vitamins, some minerals dispersed homogeneously in true solutions in food. Colloidal dispersions (1nm - 0. 2mm) --- medium stable, heterogeneous. Larger molecules such as some proteins, peptic substances, cellulose, and cooked starch are colloidally dispersed. Suspensions/ coarse dispersions --- large, unstable, heterogeneous. Large fat globules and uncooked starch granules form suspensions (> 0. 2 mm) Readily separate from the dispersion medium upon standing. Salad dressing, separate layer (suspension), add egg yolk, emulsion. Types of dispersions: according to the state of matter. The degree of dispersion may be changed by the various treatments given to foods. Sugar solution increase kinetic energy and movement of small molecules reversible, increase degree of dispersion (help dissolve) Reversible, to certain extent, if heat long time, set, not reversible. Egg whites: beating-heating, increase temperature create coagulation.
