Shelf-life of tortilla extended with fungal amylases

Corn (maize), the main source of starch and calories in the Mexican diet, is consumed mainly as tortillas, which have a short shelf-life. A fungal alpha-amylase blend (10 mu U g(-1)) was added during hydration of maize flour to produce masa, and modified the starch during tortilla cooking up to the denaturating temperature. Control and treated tortillas, fresh and staled by storage at -12 degrees C and by freeze-thaw cycles, were compared for amounts of retrograded starch, flexibility, rheological properties and by preference ranking by a panel of 75 judges. Results showed significant improvements in delayed staling and, by implication, extended shelf-life. The process was regarded as financially viable on a commercial scale.