Amylose crystallization from concentrated aqueous solution.
Maize amylose, separated from granular starch by means of an aqueous leaching process, was used to investigate spherulite formation from concentrated mixtures of starch in water. Amylose (10-20%, w/w) was found to form a spherulitic semicrystalline morphology over a wide range of cooling rates (1-250 degrees C/min), provided it was first heated to >170 degrees C. This is explained through the effect of temperature on chain conformation. A maximum quench temperature of approximately 70 degrees C was required to produce spherulitic morphology. Quench temperatures between 70 and 110 degrees C produced a gel-like morphology. This is explained on the basis of the relative kinetics of liquid-liquid phase separation vis-à-vis crystallization. The possibility of the presence of a liquid crystalline phase affecting the process of spherulite formation is discussed.
Creek
John A
JA
The Pennsylvania State University, 116 Borland Lab, University Park, 16801, USA.
Ziegler
Gregory R
GR
Runt
James
J
D000688:Amylose / Q000737:chemistry*; D003460:Crystallization; D007700:Kinetics; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D011108:Polymers / Q000737:chemistry; D013213:Starch / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction; D003313:Zea mays / Q000378:metabolism
D046911:Macromolecular Substances; D011108:Polymers; D014867:Water; D013213:Starch; D000688:Amylose