The Effects of Stirring Time at High Speed on Particle Size and Dispersion of Rice Bran γ-Oryzanol Nanocream

Abstract

γ-oryzanol is a constituent of rice bran and contains trans-ferulic acid, which is a highly effective antioxidant. It is,
therefore, very potential to be incorporated in skin-care products that can provide protections from the sun, pollution, wind, and
temperature. Such products would inhibit aging in, reduce damage of, and brighten the skin. Nanocream is cream with particle
size ranging from 40 to 91.8nm, and highly effective in delivering the active compounds. The study aimed to determine the effects
of stirring time at high speed on the characteristics of γ-oryzanol nanocream, which were particle size and dispersion. This method
employed high speed mixer, set at 15,000 rpm because the shear stress it provides can reduce droplet size. The time variables of
mixing were 0, 5, 10.5, 20, and 25 minutes. Results showed that increased stirring time produced smaller particle size, with the
smallest particle size of 48.1 12.1 nm and the largest dispersion area was 5-7 cm at 20 minutes. However, there appeared to be
a re-agglomeration at 25 minutes as the particle size increased to 54.1 17.2 nm. It was determined that the optimal stirring time
in nanocream preparation was 20 minutes. There were correlations between stirring time and particle size, and stirring time and
dispersion.