Aqueous extraction, composition, and functional properties of rice bran emulsion

The effect of temperature (20–60°C) on the aqueous extraction of emulsified rice bran oil from commercial rice bran was described. The total solids, protein, fat, and carbohydrate contents of the rice bran emulsions extracted at various temperatures were 4.82–6.99, 1.05–1.40, 0.82–1.65, and 2.65–3.36%, respectively. The mean droplet sizes of the rice bran emulsions extracted at 20, 30, 40, 50, and 60°C were 4.35, 2.92, 3.04, 4.40, and 3.73 μm, respectively. The phenolics extracted at various temperatures ranged from 63.28 to 82.51 mg/100 mL emulsion. The antioxidant capacity (oxygen radical absorbance capacity, ORAC) of rice bran emulsions extracted at various temperatures ranged from 2087 to 3505 μmol Trolox® equivalents per 100 mL of emulsion. The relationship between ORAC and the total phenolic content was highly significant (R2=0.87). The shear stress and apparent viscosity of rice bran emulsions in response to shear strain were similar to those of homogenized whole milk. Hence, the composition and functional properties show the potential of aqueous rice bran extracts as food‐grade emulsions.