Physico-chemical characteristics of rice bran processed by dry heating and extrusion cooking

Abstract

Rice bran was stabilized by dry heat and extrusion cooking method. Physico-chemical, functional, and storage characteristics of stabilized rice bran were evaluated. The rice bran stabilization affected its crude fat and crude ash contents significantly, whereas the other constituents remained almost unchanged. The content of reducing, nonreducing, and total sugars remained unaffected and did not differ significantly from raw rice bran. The neutral detergent fiber (NDF) contents of raw and dry-heat treated rice bran did not differ significantly. However, after extrusion stabilization, the NDF increased significantly. Similar effects were observed in composition of gum fiber and total fiber. The stabilization of rice bran had a significant reduction in lysine and phytic acid content. Bulk density and water absorption were higher in extruded stabilized rice bran than dry-heat treated bran. Protein solubility was maximum in raw bran, whereas damaged starch content was higher in stabilized bran. Color of the extruded bran was dark brown, whereas that of dry-heat stabilized was light brown. It was observed that dry-heat treated bran was stored up to 30 days, whereas extruded bran was stored up to 60 days without any changes in the free fatty acid content.