Cereal Chem 69:521-527   |  VIEW ARTICLE

Characterization of Starch Isolated from Oat Groats with Different Amounts of Lipid.

S. M. Hartunian Sowa and P. J. White. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

Oat starches isolated from three groat types containing different amounts of lipid (6.2, 8.0, and 15.5%) were analyzed for protein, lipid, and phosphorus contents and characterized by iodine affinity, gel permeation chromatography, scanning electron microscopy, and differential scanning calorimetry (DSC). All oat starches contained greater amounts of lipid, phosphorus, and amylose (30-34% by iodine affinity) than did starch from most other native cereal grains reported in the literature. Preliminary results from gel permeation chromatography revealed a large amount of the low-molecular-weight starch fraction, a fact suggesting the existence of intermediate molecular-weight starch. As determined by scanning electron microscopy, the oat starches had small, irregularly shaped granules 3-10 micrometers in size. As determined by DSC, the starches exhibited gelatinization onset temperatures differing significantly by starch type (ranging from 55.5 to 62.4 C), gelatinization enthalpies ranging from 2.05 to 2.20 cal/g, and a high amylose-lipid peak. After storage for up to 28 days followed by rescanning on the DSC, oat-type starches had retrograded only 32-40%, and the amylose-lipid peak had only partly reformed.