Continuous Ultrasound-Assisted Extraction of Oil from Rice Bran RSM Optimization

Rice bran is a major by-product of rice milling process which contains 10.0-20.0% oil with unique properties that make it attractive for food and pharmaceutical componies. This paper is a study on continues ultrasound-assisted extraction (CUAE) of oil from rice bran and response surface methodology (RSM) optimization of the main factors (resonance amplitude, temperature and sonication time) regard to maximize oil extraction yield (OEY%) in CUAE and comparison with those that obtained by conventional soxhlet extraction (CSE) at 65°C for 7 h. In optimum condition of CUAE including resonance amplitude of 97%, temperature of 32°C and sonication time of 52 min the OEY% was found to be 7.52% that was close to those obtained by CSE (8.0%). The results in this study revealed that the ultrasound is a promising method for extraction of oil from rice bran over the CSE by significant reducing in extraction time and temperature. It was found that RSM is a valid method for optimization and modeling the CUAE of oil from rice bran. GC-FID analysis revealed that linoleic (18:2, 31.6%), oleic acids (18:1, 40.1%), palmitic (16:0, 19.3%) and stearic (18:0, 4.1%) are the main fatty acids in rice bran oil and there is no significant difference between fatty acid compositions of extracted oil by two methods