Improvement effects of micronization on morphology, functional and nutritional attributes of stabilized rice bran

Abstract

Micronization affects physicochemical and functional properties of materials and hence might improve the quality of rice bran, following stabilization treatments. The micronization effects of stabilized rice bran via extrusion or radio frequency treatments on their morphology and functional properties, and releasable capability were investigated. Micronization reduced particle size, water binding capacity and swelling capacity of rice bran, and increased their whiteness, water solubility index, and nutrient releasability. However, no significant changes in oil binding capacity and thermal index after micronization were observed. Moreover, micronization could decrease the bulk density of rice bran stabilized by extrusion. The releasability of phenolics, flavonoids, γ-oryzanol, and minerals (K, Mg, Zn and Fe) from rice bran after micronization was improved based on in vitro digestion models. These findings suggested that micronization of rice bran following stabilization, especially extrusion treatment, could improve its functional and nutritional properties. The types of stabilization processing of rice bran, followed by micronization, should be considered practically for functional and nutritional properties.

Keywords: Micronization; Microstructure; Particle size; Radio frequency; Stabilization.