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International Journal of Polymer Science
Volume 2015, Article ID 397128, 7 pages
Research Article

Phase Transition of Waxy and Normal Wheat Starch Granules during Gelatinization

1College of Food Science, South China Agricultural University, Guangzhou 510642, China
2Institute of Agro-Products Processing Science and Technology (IAPPST), Chinese Academy of Agricultural Science (CAAS), Beijing 100193, China
3Commonwealth Scientific & Industrial Research Organization, Materials Science and Engineering, Melbourne, VIC 3169, Australia
4School of Light Industry and Food Science, CFPFRR, South China University of Technology, Guangzhou 510640, China

Received 22 September 2014; Revised 29 December 2014; Accepted 6 January 2015

Academic Editor: Önder Pekcan

Copyright © 2015 Pei Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The phase transition of waxy and normal wheat starches was systematically studied by light microscopy (LM) with a hot-stage, confocal laser scanning microscopy (CLSM) and differential scanning calorimetry (DSC). While being heated in water, waxy wheat starch showed a higher gelatinization enthalpy than that for the normal starch, which was also verified by the changes in birefringence. As confirmed by LM and CLSM, starch granules displayed an increased swelling degree with temperature increasing, and the gelatinization initially occurred at the hilum (botanical center) of the granules and then spread rapidly to the periphery. While the temperature range of birefringence was narrower than that of granule size change, the crystalline structure was melted at lower temperatures than those for the molecular orders. These results indicate that starch gelatinization was a complex process rather than a simple order-to-disorder granule transition.