The present work studied the solubilities of Quercus infectoria gall extract in supercritical carbon dioxide (SC‐CO2) system with the addition of methanol as polarity enhancer. Experimentally, the galls were extracted using SC‐CO2 at different operating pressures (20 to 30 MPa) and temperatures (50 to 70 °C). Six semi‐empirical equations (Chrastil, Adachi‐Lu, del Valle‐Aguilera, Sparks, Kumar‐Johnston and Bartle) were used to explain mathematically the solubility behaviour of the Q. infectoria gall extract. The results demonstrated that the extract solubility increases as pressure increases at fixed temperature, while at constant pressure, it increases with increasing temperature. Apparently, Bartle equation provides best correlation between experimental and calculated solubility data for gall extraction with high correlation coefficient, R2 (0.96), and small absolute average relative deviation (1.52%). © 2017 Curtin University of Technology and John Wiley & Sons, Ltd.

Swietenia mahagoni seeds have been used as folk medicine for a treatment of hypertension, malaria and diabetes. This research was conducted to obtain extracts from the Swietenia mahagoni using supercritical fluid extraction (SFE) with pure CO2 solvent, in order to evaluate the high- pressure method in terms of process yield and biological activity. The various conditions namely flow rate of CO2 were set up at 2, 3, and 4 ml/min; at constant pressures (P) and temperature (T). The sample extracts obtained by SFE with CO2 flow rate of 4 ml/min showed the highest percentage yield (19.67%) compared to the others. The antioxidant potential of the extracts was evaluated by the DPPH method and Folin- Ciocalteu method. The solvent flow rate of 2 ml/min gave the lowest percentage of yield, but good results in antioxidant activity and total phenolic content. The antimicrobial activity of the extracts against Gram-positive (Bacillus subtilis, Staphylococcus aureus) and Gram-negative (Escherichia coli) was evaluated based on the inhibition zone using disc diffusion assay. These results ensured that Swietenia mahagoni seed extract had inhibitory effects on the growth of Bacillus subtilis, Staphylococcus aureus and Escherichia coli at concentration of 100 mg/ml.

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The aim of this study was to determine the oil recovery from Swietenia macrophylla seeds and its solubility in Supercritical CO2 extraction process. Experimentally, the oil recovery from the seeds were conducted at 15-35 MPa and 40-60°C by Supercritical CO2 extraction process. Density-based models such as Chrastil and del Valle and Aguilera models were used to correlate the solubility data of Swietenia macrophylla seeds oil. The high oil recovery obtained at 35 MPa and 60°C was 6.609 mg oil/g CO2 while the lowest oil recovery was at 15 MPa and 40°C (0.810 mg oil/g CO2). Chrastil model provide the best correlation between experimental and calculated solubility data for oil recovery from Swietenia macrophylla seeds with lowest value of average absolute percent deviation (AAPD) which is 0.33% compared to del Valle and Aguilera model (0.39%).