Ultrasound Assisted Extraction of Oil from Rice Bran: A Response Surface Methodology Approach

In the present study, ultrasound-assisted extraction of oil from rice bran was investigated through response surface methodology (RSM), where process variables were amplitude level (50–100%) and sonication time (5-30 min). It was found that all process variables had significant (p<0.05) effects on the response variable. A central composite design (CCD) was used to determine the optimum process conditions. Optimal conditions were identified as 93% amplitude level and 26 min sonication time for maximum crude oil yield of 10.8%. It was found that oil yield by ultrasound-assisted extraction using ethanol as solvent was higher than that of the conventional method using hexane or ethanol as solvent. Furthermore peroxide value and free fatty acid values were comparable in all the extracted samples. GC-MS analysis confirmed that ultrasound treated samples had a higher percentage of unsaturated fatty acids compared to conventional extraction using hexane. It was also observed that solvent extraction using ethanol showed higher percentage of the unsaturated fatty acid compared to hexane as solvent. This study confirms that ultrasound assisted extraction using ethanol as solvent can retain maximum unsaturated fatty acid compared to conventional hexane extracted sample, which is a food grade solvent. Hence in conclusion ultrasound assisted extraction has the potential to replace the conventional solvent extraction. Ultrasound Assisted Extraction of Oil from Rice Bran: A Response Surface Methodology Approach