EXTRACTION OF OIL FROM GRAPE SEEDS WITH SUPERCRITICAL CARBON DIOXIDE
INTRODUCTION Grape seeds are known as a waste byproduct of juice and wine production. They contain oil between 10 and 20%, depending on grape variety, which has high amounts of unsaturated fatty acids, usually linoleic and oleic acids ranged from 53 to 78% and 16 to 31% (Bail et al., 2008; Sabir et al., 2012). Oil from grape seeds is also constituted with natural antioxidants, among others, tocopherols in the 50 to 520 mg/kg range that are responsible for health-benefits such as lowering cholesterol levels and alleviating cardiovascular diseases (Bail et al., 2008; Sabir et al., 2012). Grape seed oil is a promising lipid for human consumption due to its nutritional constituents. The use of supercritical carbon dioxide (SC-CO2) is an effective method for oil extraction. It produces purer oil and preserves bioactive components of the oil when compared with the typical hexane extraction and refining. This is because the low critical point (Pc = 7.3 MPa, Tc = 31°C) and characteristics of CO2 that allows for organic solvent free extraction, making it safe and efficient for separation and fractionation of thermally sensitive oils (Agostini et al., 2012). In the present study the effects of pressure (20, 30 MPa) and temperature (30 °C, 40 °C, 50 °C) were investigated on the oil yield. The quality of SC-CO2 extracted oil in term of fatty acid content was compared to that of hexane-extracted oil.
Recovery of grape seed oil by liquid and supercritical carbon dioxide extraction: a comparison with conventional solvent extraction
Abstract In this work the extraction of grape seed oil by means of liquid and supercritical carbon dioxide as solvent is described. The operating conditions to determine the maximum extraction yield were studied. The efficiency of supercritical fluid extraction (SFE) was similar to that obtained by conventional liquid extraction, but the quality of the supercritically extracted oil was higher, equivalent to a degummed, liquid- extracted oil. It is considered that SFE is competitive with conventional liquid extraction, because the solvent distillation and oil refining stages can be omitted.
Investigations on the rôle of organic matter in plant nutrition
1. As the result of decomposition of green manure in a swamp soil, the coarse fractions (including coarse and fine sand) of the surface layer (first 3 inches) decreased by 11·2 per cent. while the fine ones (silt+clay) increased by 9·8 per cent. in the course of 43 days. The effect was less pronounced in the manured soil maintained at 60 per cent. saturation, while no alteration was to be noticed in the case of the unmanured specimens. 2. Treatment with dilute hydrochloric acid prior to dispersion had no appreciable effect on the estimates of mechanical composition obtained in the different cases. Loss in solution was also comparatively small. 3. The silica-sesquioxide ratio increased slightly as the result of decomposition of green manure in swamp soil. The composition of the fine fractions was also altered, the total percentages of the oxides of iron, aluminium and silicon increasing from 90·5 to 99·3 in the course of 71 days. 4. The practical significance of the above and related observations has been discussed.