Author
 |
Grant, Linda |
|
Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/21/1998 Publication Date: N/A Citation: N/A Interpretive Summary: A prerequisite for the study of starch properties, such as its gelling behavior, is to isolate starch granules from plant tissue (i.e. wheat whole kernels and/or flour) without causing undue damage. This would extend also to the subsequent handling of the starch, such as the drying and grinding procedures. Starch granules can be physically altered during the drying and grinding processes which may result in changes in the gelatinization patterns. These changes could give inaccurate scientific results. Although this study is more applicable to scientific research, the results could also be useful in industry for some food applications Technical Abstract: The effects of two different methods of starch isolation, drying and grinding on gelatinization and retrogradation properties were investigated. Starch was isolated from whole wheat and flour of four hard red spring (HRS) wheat cultivars. Portions of each starch isolate were freeze-dried or air-dried and portions of each dried starch was ground using a mortar and pestle or a Wiley Jr. mill. Less starch damage was obtained for freeze-dried starch regardless of isolation method or grinding technique and for all starches derived from whole wheat. Highest starch damage was obtained for air-dried starch isolates. Wiley milled starch isolates showed higher water-binding capacity. Whole wheat starch isolates had higher peak, lower trough and lower final viscosities, as determined by a Rapid Visco-Analyzer (RVA), than starch isolates from flour. Major effects of all treatments on DSC gelatinization properties showed lower onset temperature for flour starch isolates, lower peak temperature for freeze-dried starches and no effects due to grinding. Endotherms of all starches after refrigerated storage and freeze-thaw cycling were lower than for gelatinization |
