MICROSTRUCTURE CHANGES IN WHEAT-FLOUR TORTILLAS DURING BAKING

The texture of tortillas depends upon the retention of gases by the gl uten matrix. Raw and hot-pressed tortilla dough was dense, with few ai r cells. Intact starch granules were embedded in a gluten matrix. Her- pressing sealed the surface and edges. The tortilla passed through thr ee tiers of a gas oven and expanded due to steam and carbon dioxide fo rmation during baking. The edges and surface remained sealed, allowing the tortilla to expand; the center of the tortilla was split apart. S urface starch granules were dehydrated and ungelatinized throughout ba king. The combined use of SEM and ESEM facilitated efforts to discern the internal structure.