Effects of rice flour size fractions on gluten free rice bread

Abstract

Fractionation (F-1, F-2, and F-3) of semi-dry milled rice flour (SDMRF) was performed using air-classification wheel speeds (ACWS, 1,000, 2,000, and 3,000 rpm) to identify suitable size fractions for preparation of gluten-free rice bread (GFRB). Characteristics and effects of fractions on GFRB were investigated. Fractions had higher water absorption indices than unfractionated flour (control). Fractions were smaller in size, and the amount of damaged starch was larger for higher ACWS values. The F-1 fraction had higher peak viscosities and specific volumes than other fractions. The F-3 fraction had lower values. GFRB prepared using the F-1 fraction had a lighter air-cell structure and lower hardness than control bread. From sensory evaluations, the particle size of SDMRF affected the appearance of GFRB. GFRB prepared using the F-1 fraction had more uniform and smaller air-cells. The quality of GFRB can be improved by controlling the particle size of flour.