ENZYME-RESISTANT STARCH .3. THE QUALITY OF STRAIGHT-DOUGH BREAD CONTAINING VARYING LEVELS OF ENZYME-RESISTANT STARCH

Breads with varying levels of enzyme-resistant starch (RS) were obtained by replacing 24% of wheat flour (RS content 14.5%) with 4% vital wheat gluten and 20% of one of the following: corn starch (CS), high-amylose corn starch (HA), or extruded retrograded high-amylose corn starch (ERHA). RS levels were 44.1, 83.2, and 29.5%, respectively. Breads were produced by the Finney (1984) procedure (100.00 g of flour or 76.00g of flour, 4.00 g of gluten, and 20.00 g of starch). All had excellent taste and shelf life, except for the CS breads. RS levels of bread were lower than could be predicted from the analytical data of the starting materials, which shows that some RS destruction occurs in the breadmaking process. Thus, one day after baking, the RS content of breads containing wheat flour, CS, HA, and ERHA was 0.0, 0.4, 7.7, and 8.4%, respectively. The latter breads showed the presence of retrograded amylose or resistant granules. After seven days of storage, the RS levels had increased to 4.0, 4.4, 10.2, and 11.0%, respectively. Differential scanning calorimetry measurements confirmed that the increase can probably be ascribed at least in part, to increases in the levels of retrograded amylopectin. Bread volumes were 663.9, 654.3, 655.9, and 621.5 ml, respectively. The softest breads were those produced with ERHA; the least soft ones were those with CS; the breads with wheat flour and HA had intermediate levels of softness.