Scanning Electron Microscopy Studies of Wheat,Potato and Corn Starch during Gelatinization

The gelatinization of a commercial wheat and potato starch and two types of corn starch (Amaizo Amylomaize VII and Amaizo Amioca Pearl starch) was examined by the scanning electron microscope. Concomitantly, the loss of birefringence in the wheat, potato and corn starch was followed with the light microscope. Swelling and deformation of the starch granules observed in the scanning electron microscope correlated with the loss of birefringence in the light microscope. The gelatinization range of the starches was detected with the scanning scope. Swelling of the wheat starch granules was first observed in the larger A-type granules. Amylomaize VII retained granular structure until approximately 95 °C even though birefringence changes were observed as low as 69°C. Some evidence of structural changes were evident at 83°C. Amioca Pearl underwent structural changes at approximately 68°C and abruptly lost granular structure at approximately 71 °C.