EFFECT OF EXTRACTABLE LIPID ON THE VISCOSITY CHARACTERISTICS OF CORN AND WHEAT STARCHES

The defatting of both corn and wheat starch with 85% methanol yields starches which start to gelatinise at lower temperatures and have increased overall viscosities compared with untreated starches. The lipids extracted from wheat and corn starch with 85 % methanol were similar in total amount but showed very large differences in the proportions of neutral and phospholipids. The extracted corn lipids contained eight times as much neutral lipids (mainly free fatty acids) as phospholipids whereas the proportions of neutral and phospholipids in wheat starch were approximately equal. Addition of extracted lipids to defatted starches significantly modified the swelling and viscosity characteristics. Addition of wheat and corn lipids to potato starch (which contains almost no lipids) indicated that the higher percentage of phospholipids in wheat starch probably contributed towards the lower viscosity characteristics of wheat starch compared with corn starch. Copyright © 1979 John Wiley & Sons, Ltd