Cereal Chem 69:275-279   |  VIEW ARTICLE

Corn Starch Changes During Tortilla and Tortilla Chip Processing.

M. H. Gomez, J. K. Lee, C. M. McDonough, R. D. Waniska, and L. W. Rooney. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

Structural and molecular changes of corn starch during tortilla chip processing were evaluated by X-ray, liquid chromatography, viscosity, and microscopic techniques. Cooking disrupted the crystalline structure of corn starch. The starch then recrystalized or annealed during steeping to form a new polymeric structure. Grinding of cooked corn released starch granules from the endosperm and reduced their crystallinity. Tortilla baking caused significant losses in starch crystallinity, and frying of tortilla chips caused further gelatinization and the formation of amylose-lipid complexes. Starch solubilization was unchanged after alkaline cooking and increased after steeping. The physical disruption of the kernel caused by grinding further increased the starch solubilization in masa. Baking and frying reduced starch solubility. Steeping and alkaline cooking caused swelling and agglomertion of starch granules throughout the endosperm. Grinding the nixtamal caused complete physical disruption of kernels, resulting in dispersion of swollen starch granules. Tortilla baking caused partial to complete starch gelatinization. Tortilla frying resulted in total gelatinization in the internal areas of the chip, but starch granules on both surfaces of the chips displayed strong birefringence.