PRELIMINARY INVESTIGATION OF GALLIC ACID EXTRACTION FROM JATROPHA CURCAS LINN. LEAVES USING SUPERCRITICAL CARBON DIOXIDE WITH METHANOL CO‐SOLVENT

ABSTRACTThe leaves of Jatropha curcas Linn. contain antioxidant, anticancer and anti‐HIV compounds. This research investigated the extraction of the phenolic compound, gallic acid (GA), from Jatropha curcas Linn. leaves using supercritical carbon dioxide (SCCO2) and methanol co‐solvent. The SCCO2 pilot plant extractor, which was 10 times the capacity of a lab scale unit, was designed and built by our research group using a hydraulic pump instead of high pressure pump. The operating pressure was varied from 20 to 40 MPa; the temperature was varied from 40 to 60C; the particle size was varied from 10 to 40 mesh and the modifier concentration was varied from 0 to 70% (v/v) aqueous methanol. An orthogonal L9 (3)4 experimental design was applied to determine the optimal extracting condition and the effect of the parameters. The largest extraction yield from the experiment was 75.39 mg/kg dry weight of leaves at 40 MPa, 50C and 10–16 mesh particles using a 70% (v/v) methanol modifier. However, from the analysis of L9 (3)4, the optimal operating conditions were at 20 MPa, 50C and 10–16 mesh particles using a 70% (v/v) methanol modifier. It was found that temperature, particle size and modifier concentration had a statistically significant influence (at 85% confidence level) on the GA extraction yield. The fact that pressure was not found to be statistically significant is possibly due to the difficulty in controlling pressure in the pilot plant.PRACTICAL APPLICATIONSA pilot plant scale supercritical fluid extraction unit, which was 10 times the size of typical laboratory units, was designed and built in our lab using a low cost hydraulic pump to replace a high pressure pump. The pilot plant was able to reasonably extract gallic acid from the leaves of Jatropha curcas Linn. Preliminary experiments resulted in an optimal set of operating conditions which can be used as a starting point in future work. The system will eventually be instrumented and controlled to access operating data as well as maintain the operation of the extractor at desired set‐points. The advantage of using SCCO2 for the extraction is to achieve pure quality product. Gallic acid, which is one of the phenolic compounds in physic nut leaves, is characterized by various properties such as anti‐inflammatory, antimutagenic, anticancer, antioxidant and antiviral agent.