Optimization of bromate-free improver formulations for use with a Mexican bread flour and with blends of Canadian hard red spring and prairie spring wheat flours
The effect of bread improvers on the quality characteristics of white panbread made with a Mexican commercial wheat flour and with blends of hard red spring and prairie spring wheat flours were evaluated. The study was divided into two optimization experiments. A rotatable central composite design was used in both experiments to identify the main effects and interactions between the factors. In the first optimization experiment, two baking tests, a liquid ferment and the Canadian Short Process, were compared for sensitivity to improver formulations containing diacetyl tartaric acid ester of monoglycerides (DATEM), ascorbic acid, and a-amylase. The liquid ferment was more sensitive to the effect of the improvers than the Canadian Short Process. Ascorbic acid and a-amylase showed fewer significant effects in the Canadian Short Process than in the liquid ferment. Using the liquid ferment, high quality loaves were possible at any given concentration of DATEM. With low DATEM, the requirements for a-amylase were high (above 80 SKB units), while at higher levels of DATEM, a-amylase requirements were as low as 40 SKB units. However, the liquid ferment doughs showed excessive stickiness after mixing. A further experiment indicated that appropriate handling properties could be attained at a reduced water absorption of FAB - 3%. In the second optimization experiment, the liquid ferment baking test was used to evaluate the effects of ascorbic acid and a-amylase on flour blends. DATEM was used at fixed level of 0.375%. Hard red spring (CWRS and CWES) were blended at different ratios with CPS white and red flours. CWRS performed better than CWES when blended with CPS white. Optimized combinations of ascorbic acid and a-amylase, that satisfied all the optimization quality criteria, could be identified at any level of CWRS, while optimized combinations were only identified at high levels of CWES. Ascorbic acid interacted strongly with CWRS but not with CWES. This was more evident in loaf volume where at low levels of CWRS higher loaf volumes could be attained by using higher concentrations of ascorbic acid. Alpha-amylase had a strong interaction with CWRS. Concentrations required to maximize loaf volume were lower with higher amounts of CWRS. ln the CWES blends, maxima in loaf volume were achieved at 75 SKB units a-amylase. High quality loaves could be made with a high percent of CPS white flour blended with CWRS flour by using high concentrations of ascorbic acid (>119 ppm) and low to medium levels of a-amylase (16-88 SKB units).