Extraction of oil from Jatropha curcas seeds by subcritical fluid extraction

- The Jatropha oil was extracted using subcritical fluid extraction.
- The optimum conditions were obtained by response surface methodology.
- The extracted oil showed a good appearance and a high yield (40.28%).
- The extraction processes of different extraction were modeled.
- Subcritical fluid extraction is an efficient method for the plant oil extraction.

In this study, a method for the extraction of oil from Jatropha curcas seeds using subcritical fluid extraction was developed. Extraction conditions, optimized by response surface methodology, were as follows: ethanol/hexane, 7:1 mL/mL; solvent/solid ratio, 30 mL/g; time, 45 min. The yield of the oil extracted from the J. curcas seeds by this method was then compared to different extraction methods (reflux extraction, microwave extraction, ultrasonic extraction and subcritical fluid extraction). The oil samples were analyzed using gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectrometer (FTIR). Results showed the maximal yield of Jatropha seed oil under the conditions tested of subcritical fluid extraction reached 40.28 g oil/100 g dry seeds at a temperature of 90 °C, a pressure of 0.5 MPa. Based on the comparison between different extraction methods, the oil extracted by subcritical fluid extraction had a good appearance and a high yield. In addition to subcritical fluid extraction, the extraction processes of maceration extraction, reflux extraction, and ultrasonic extraction were modeled and discussed. The subcritical fluid extraction method was found to compare adequately to the other methods, and provided a good amount of correlating data.

Response surface for the effect of ethanol/hexane and solvent/solid ratio on the oil yield at a fixed time of 25 min (A), effect of ethanol/hexane and time at a fixed solvent/solid ratio of 20 mL/g (B), effect of solvent/solid ratio and time on the oil yield at a fixed ethanol/hexane of 4:1 mL/mL (C) on the oil yield at 90 °C, 0.5 MPa.