Toshiko Fujii

Role of Starch Granules in Controlling Expansion of Dough During Baking

ABSTRACT The role of starch granules in the expansion of doughs during baking was investigated using artificial flours made from dry vital wheat gluten and wheat starch, potato starch, or tapioca starch. The three starches were selected because of their diverse gelatinization properties. Baking tests on flour from tapioca starch gave the largest loaf volume and the most extensive postbaking shrinkage. Potato starch flour gave the smallest volume and the least shrinkage. Amylograph test data, dough expansion under decreased pressure, progress of expansion during baking, and scanning electron microscopy revealed the role starch granules play in ideal baking conditions. Starch granules should not gelatinize early in the baking cycle as potato starch does but should gelatinize later in the baking cycle as wheat starch does. This prevents early setting of the dough which inhibits expansion. Starch granules should not disrupt and fuse together during gelatinization as tapioca starch does, forming an impermeable...

Determination of the Degree of Gelatinization of Heated Starch

The degree of gelatinization of starch is usually defined as the ratio of enzymatic digestibility of a sample starch to enzymatic digestibility of the starch gelatinized with alkali. In the case of the starch samples heated with small amount of water, however, following incomplete gelatinization with alkali was observed. In this paper, we proposed that the degree of gelatinization was directly defined as the percentage of hydrolysis of starch with glucoamylase on the basis of the amount of glucose formed by acid hydrolysis of the starch samples. The degree of gelatinization of cooked starchy foods by our method and the conventional method was also discussed.