NFS 033 Lecture Notes - Lecture 7: Amylose, Amylopectin, Retrogradation
5 Mar 2018
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Document Summary
Amylose glucose polymer (hundreds to thousands of glucose units), linear (no branches), chains form helical structures held together by hydrogen bonds, long chains able to associate with each other. Amylopectin glucose polymer, branched, tree-like structures dont pack together well. Starch properties amylopectin and amylose molecules form semi-ordered structure in starch granules (associate via hydrogen bonds) Gelatinization absorption of water by starch molecules upon heating and formation of starch-water gel. Hydrogen bonds between amylose and amylopectin molecules break. Increased association between amylose/amylopectin molecules and water (via hydrogen bonds) Amylose molecules leak out of granules- form mesh . Waxy starch lower starch content (more water) and less amylose (more amylopectin) Mealy starch higher total starch content (less water), and more amylose (less amylopectin) Starch is a polymer of the sugar glucose. Amylose is very prone to retrogradation due to because it is linear and can stack closely together and can make many starch- starch hydrogen bonds.
