Effect of ovalbumin on the quality of gluten-free rice flour bread made with soymilk

- Interior of gluten-free rice flour bread using soymilk was improved by adding OVA.
- OVA enhanced the thermal coagulation of gas cell membranes made with soy globulin.
- By the interaction of soy globulin and OVA, batter viscosity increased.
- OVA caused single rice starch granules to form compound rice starch granules.

The use of soymilk instead of water affects the rising of gluten-free rice flour bread into the shape of a muffin. However, when baking bread into a loaf, gas cells at the center of the crust, where thermal conduction is lowest, collect to form a hollow in the loaf. The goal of this study was to assess the components that affect the quality of gluten-free rice flour bread made with soymilk. Adding more than 1.25% of ovalbumin (OVA) to the rice flour prevented formation of this hollow. In addition, OVA levels greater than 2.5% helped the bread rise further through oven spring, which increased specific loaf volume. These improvements resulted from an increase in thermal coagulation of gas cell membranes and an increase in batter viscosity due to interactions between soy globulins and OVA that promoted starch granule aggregation. Thus, even though OVA levels greater than 2.5% increased the specific loaf volume, they also made the crust harder. As a result, the optimum OVA level is 1.25% of the rice flour.