  2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center  |
|
243
Thermal and pasting properties of dry-milled fractions of normal, waxy and high-amylose corn. K. SEETHARAMAN (1), N. Yao (1), T. Beta (2), C. J. Bern (3), and P. J. White (2). (1) Department of Food Science, The Pennsylvania State University, University Park, PA 16802; (2) Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011; (3) Department of Agricultural and Biosystems Engineering, Iowa State.
Differences in the functional properties of dry-milled fractions of normal, waxy and high- amylose corn were investigated. Corn, grown in Ames, Iowa, was dry-milled using the short-flow procedure. Milled corn was aspirated and fractionated, by using a Ro-Tap sieve shaker, into six fractions: above sieves 3.5, 5, 7, 12, and 30, and below sieve 30 (flour). The fractions were hand cleaned to remove residual germ fraction and ground in a coffee grinder for use in further analyses. The fraction with the greatest yield was above sieve 7 for all three corns, with normal corn having greater yields than either waxy or high-amylose corn. The change in enthalpy of gelatinization of the various endosperm fractions was measured using Differential Scanning Calorimetry. Enthalpy values of the normal corn fractions ranged from 9.6 J/g for the fraction above sieve 5 to 7.5 J/g for the flour fraction. Waxy corn fractions had greater enthalpy values than did normal corn but did not reveal any trends whereas the enthalpy of high-amylose corn fractions ranged from 3.5 J/g for the fraction above sieve 5 to 10 J/g for the flour. The pasting properties of the various fractions, measured with a Rapid ViscoAnalyzer showed that all fractions of normal corn had greater peak and final viscosities than did the corresponding fractions from waxy or high-amylose corn. The fraction above sieve 7 had the greatest peak and final viscosities among the other fractions for all three corns. These findings provide a greater understanding of the fracture properties of corn and the resulting impact on the functional properties of the different fractions.
Copyright 2001
The American Association of Cereal Chemists