Meeting Abstract - Poster Presentation

Effects of protein-modifying enzymes on the structure and shelf-stability of flour tortillas
J. ALVIOLA (1), R. Waniska (1)
(1) Texas A&M University, College Station, TX, USA
Cereal Foods World 52:A34

Effects of protease and transglutaminase (TG) on dough and tortilla structures, and on shelf-stability were determined to infer the role of gluten in tortilla production and storage. Confocal microscopy was used to study the effects of the enzymes on dough and tortilla microstructure. Control and treated tortillas were prepared using standard procedures in a pilot-plant scale hot-press and gas oven, and evaluated for texture properties and shelf-stability after 0.04, 1, 3, 7, 14 and 21 days. Micrographs of control dough had thin protein strands forming a continuous, web-like matrix. Protease-treated dough had pieces of proteins in place of the continuous matrix, while TG-treated dough had thicker protein strands that were heterogeneously distributed. Control tortillas had a well-developed and well-distributed continuous protein structure. Protease-treated tortillas had a continuous structure despite being composed of hydrolyzed proteins in the dough, while the TG-treated tortilla retained clumps of proteins. Protease-treated tortillas required the least force, distance and work to rupture. Tortillas prepared with protease and TG broke on the third and seventh days of storage, respectively, while the control broke after two weeks using the subjective rollability evaluation. Both protease (hydrolyzing enzyme) and TG (cross-linking enzyme) weakened dough and tortilla structures. Thus, it appears that at least a moderate gluten network is necessary to impact a longer retention of tortilla flexibility during storage.