61A-38 |
Antistaling properties of a maltogenic amylase on corn tortillas |
F. J. BUESO1, L. W. Rooney1, R. D. Waniska1, and R. G. Moreira2. (1) Soil & Crop Sciences Dept., Texas A&M Univ., Cereal Quality Lab., College Station, TX 77843-2474, (2) Agricultural Engineering Dept., Texas A&M Univ., Food Engineering Lab, College Station, TX 77843 Novamyl 1500 MG is a bacterial amylase which removes DP 2-7 oligosaccharides from amylopectin and amylose without causing gumminess. The objective of this study was to determine the ability of Novamyl to delay corn tortilla staling at room temperature. Three levels of the amylase (0, 450 and 600 MAU) and three levels of carboxy-methyl-cellulose (0, 0.25 and 0.5 %) were evaluated. Tortilla yield (kg tortillas/kg dry masa flour), pH and moisture were measured immediately after baking. Subjective and objective texture of tortillas was evaluated 0, 3, and 24 h after baking. Stress relaxation was performed to obtain final stiffness and energy dissipated, which are indicators of tortilla viscoelasticity. All treatments produced optimum masas and tortillas with good sensory properties. Moisture (46%) and pH (5.3) were not significantly changed by amylase compared to control. Yields were significantly reduced by Novamyl alone (0.74 and 0.57 kg tortillas/kg, respectively) compared to tortillas with 0.5% CMC (1.03 kg /kg). A combination of 0.25 % CMC and 600 MAU of Novamyl gave tortilla yields similar to 0.5% CMC (0.99 kg/kg). Subjective and objective texture of fresh tortillas was similar for all treatments. Rollability and pliability did not significantly change for tortillas with combinations of Novamyl and CMC 24 h after baking. However, pliability was significantly reduced by 600 MAU of amylase. A 450 MAU dose of amylase significantly reduced final stiffness and increased the level of dissipated energy 24 hours after baking compared to the control (no additives) and tortillas with only CMC. A combination of 0.5% CMC and 600 MAU of Novamyl gave tortillas with the lowest final stiffness and the highest yield (1.15 kg/kg) (p<0.05). Novamyl could have interfered with amylopectin re-crystallization and produced less staled tortillas than CMC. Further studies will evaluate lower levels of Novamyl and other amylases on amylopectin re-crystallization.
Session 61A, Carbohydrate
|