Keila K. Aracava

Experimental data and modeling of rice bran oil extraction kinetics using ethanol as solvent

ABSTRACT The extraction kinetics of rice bran oil (RBO), free fatty acids (FFA), and oryzanol using ethanol (0 and 6.3 mass % of water) at 40°C–70°C were investigated. High extraction temperatures increased the yields of RBO and oryzanol by increasing the diffusivity of the solvent, regardless of its water content. Two models that permitted the estimation of mass transfer and diffusion coefficients were fitted to the oil extraction data with low average relative deviations (≤5.92%). The diffusion coefficient (1.93–7.46 × 10–10 m2∙s–1) increased with increasing temperature and decreasing hydration of the solvent.

Effect of the type and level of hydration of alcoholic solvents on the simultaneous extraction of oil and chlorogenic acids from sunflower seed press cake

BACKGROUND The present study aimed to evaluate the replacement of hexane by alcoholic solvents in oil extraction from sunflower seed press cake. The use of ethanol and isopropanol has important advantages, including low toxicity and good operational safety. Thus, in the present study, solid-liquid extractions were performed in a single stage from 60 to 90 °C and in consecutive extractions in three stages at 90 °C. RESULTS Solvent hydration negatively affected the extraction of oil but favored the extraction of chlorogenic acids (CAs), especially when ethanol was used. Regarding oxidative stability, the oils extracted using ethanol presented long induction times, which could be related to the high levels of not only CAs and tocopherols, but also phospholipids. CONCLUSION Alcoholic solvents can be used for extraction to produce sunflower seed oil containing minor compounds that give it greater oxidative stability. In addition, the results obtained using hydrous ethanol showed that this solvent can yield defatted sunflower seed meal with a low content of CAs, enabling future use of the protein fraction.