  2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center  |
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256
Functional and structural properties of unusual starches from developmental corn lines. Y. JI (1), K. Seetharaman (2), L. M. Pollak (3), S. Duvick (3), J.-L. Jane (1), and P. J. White (1). (1) Department of Food Science and Human Nutrition, Iowa State University, Ames, IA; (2) Department of Food Science, The Pennsylvania State University, University Park, PA 16802; (3) USDA-ARS, Department of Agronomy, Iowa State University, Ames, IA.
The objectives of this research were to evaluate functions and structures of starches from exotic x adapted inbred lines and exotic breeding crosses(exotic populations x adapted lines), and to establish relationships between the fine structure and functional properties of the starches. Several S4 and S5 lines containing a high frequency [> 70%] of kernels with unusual thermal properties as measured by Differential Scanning Calorimetry [DSC] [gelatinization onset temperature < 60°C or range of gelatinization > 14°C] were selected for further characterization]. The pasting properties of starches were measured with a Rapid ViscoAnalyser [RVA]. All selected starches from the developmental lines had greater peak viscosity, final viscosity and set back values than did normal starch from Mo17. All unusual starches contained a lesser proportion of chains with degree of polymerization [dp] greater than 16 and a greater proportion of branch chains below dp 13 than did normal starch, as measured by high-performance anion-exchange chromatography. These structural difference may result in a less stable crystalline structure within the starch granules, causing greater viscosity and weaker gel strength. Thus, although the gelatinization onset temperature measured using DSC was lower, the hydration and viscosity development of the starches measured with the RVA were greater for the unusual starches than for normal corn starches. These results suggest that incorporation of exotic alleles into Corn Belt germplasm is an excellent means to obtain value-added traits to produce starch with desirable functions.
Copyright 2001
The American Association of Cereal Chemists