Cereal Chem. 71:443-450 | VIEW
Structure and Physicochemical Properties of Starches from Oat with Different Lipid Contents.
L. Z. Wang and P. J. White. Copyright 1994 by the American Association of Cereal Chemists, Inc.
Oat (Avena sativa L.) starches isolated from three lines of groats containing a range of lipid contents (6.2, 8.0, and 11.2%) were evaluated. The lipid content of the starches varied from 1.08 to 1.18%, which was higher than that of corn (Zea mays L.) starches (0.56-0.66%). The amylose content of oat starches (measured by blue value) ranged from 22.1 to 26.6%. In corn starches, it ranged from 24.0 to 24.6 and was positively correlated with the starch-lipid content. The oat starches had a smaller average granule size, lower molecular weight, and lower clarity of starch paste than did corn starches also evaluated in this study, as measured by scanning electron microscopy, limiting viscosity number, and percentage transmittance, respectively. The granule size and clarity of oat starches were negatively correlated to amylose and starch- lipid content. The swelling power and solubility of starches increased with a rise in temperature from 85 to 95 C. The increased values were higher in oat starches than they were in corn starches. Furthermore, as measured by high-performance size-exclusion chromatography, oat starch amyloses had a shorter chain length than did corn starches, and the chain length tended to decrease with increased amylose and starch- lipid content. Differences in chain length and chain-length distribution of amylopectin also were noted among oat starch types, with the short chain length (A and short B chains) of amylopectin increasing with increased amylose and starch-lipid content.