Effect of Defatted Soybean and Soybean Isolate Fortification on the Nutritional, Physical, Chemical and Sensory Properties of Wheat Flour Tortillas

Wheat flour fortified with 11.1% defatted soybean meal (SBM) or 5.6% soybean isolate (SBI) was processed into flour tortillas. Fortified tortillas contained 35% more protein and twice as much lysine as the 100% wheat flour tortilla. Addition of SBM or SBI decreased dough elasticity but increased dough water absorption and the force required to stretch the dough. The SBM fortified tortilla had better texture (P < 0.05) than the 100% wheat flour tortilla and similar flavor and color (P > 0.05). Rats fed fortified tortillas gained three times as much weight and doubled the protein efficiency ratio (PER) when compared to rats fed wheat flour tortillas. The apparent biological and net protein utilization values of the fortified tortillas were similar (P > 0.05) and higher (P < 0.05) than the wheat flour tortilla. The SBI fortified tortilla had a higher apparent protein digestibility (P < 0.05) than the 100% wheat flour and SBM fortified tortillas.