Extraction of seed oils

Stahl E., Schiitz E. and Mangold H.K. (1980) Extraction of seed oil with liquid and supercritical carbon dioxide. J. Agric. Food Chem. 28, 1153-7. 

Stahl, E. T.M. Schultz H.K. Mangold. Extraction of seed oils with liquid and supercritical carbon dioxide,/. Food Chem. 1980,28, 1153—1157. 

An analysis of this model makes it evident that such models would be more successfully applied to extractions of seed oils, or similar materials, wliich contain species of similar characteristics in the extract, rather than for the extraction of materials like essential oils, containing species with a wide range of characteristics. This reasoning is based on the fact that the outer spherical shell is assumed to be free of all extractable material, i.e. a barren matrix. In some cases some materials may be adsorbed on the pore walls, etc, of this barren matrix, on their way out of the particle. Under such circumstances the model assumes that such mechanisms as adsorption or de-sorption are not the controlling steps. 

Triglycerides in seed oils are readily soluble in SC-CO2 at 40 C and at pressures higher than 280 bars. The main parameters important for efficient oil extraction in this method are particle size, pressure and residence time. Small particles of about 1mm mean diameter or less and high pressures (300-500 bar) can strongly reduce the extraction time. After extraction, the SC-CO2 tryglicerides solution is sent to a separator working at subcritical conditions. This operation reduces the solvent power of CO2 and allows the recovery of oil. The complete elimination of gaseous CO2 from oil is also accomplished in this step. The SC-CO2 extraction of seed oils has been tested up to pilot seale for several seed oils. 

Stahl E, Schutz E, Mangold HK. 1980. Extraction of Seed Oils with Liquid and Supercritical Carbon Dioxide. J. Agric. Eood Chem. 23 1153-1157. 

Stahl E, Quirin K-W, Blagrove RJ. 1984. Extraction of Seed Oils with Supercritical Caibon Dioxide Effect on Residual Proteins. J. Agric. Pood Chem. 32 938-940. 

Mechanical Pressing. Historically, the first large commercial production of oils from seeds and nuts was carried out using labor-intensive hydraulic presses. These were gradually replaced by more efficient mechanical and screw presses. Solvent extraction was developed for extraction of seeds having low oil content. For seeds and nuts having higher oil content, a combination of a screw press followed by solvent extraction is a common commercial practice (prepress—solvent extraction). 

Liquids can be extracted from solids by leaching. As the name implies, the soluble liquid contained in a solid is leached out by contacting the solid with a suitable solvent. A principal application of leaching is in the extraction of valuable oils from nuts and seeds such as, palm oil and rape seed oil. 

Flair-growth stimulant. Water extract of the grain, applied externally on adults at a concentration of 10%, was active. The biological activity has been patented . Flypocholesterolemic activity. Unsaponi-fiable fraction of seed oil, administered orally to rats at a dose of 0.4% of the diet. 

China. Hot water extract of seed is taken orally for impotence " . Seed oil is taken orally for tuberculosis . 

Jordan. Seed oil is taken orally to induce lactation and as an antitussive Malaysia. Hot water extract of seeds is taken orally as an emmenagogue and in a large dose as an abortifacient . Seed oil is taken orally as an emmenagogue and used by males as a tonic for sexual neurasthenia . 

A cylindrical extractor, 1-m long, is filled with crushed-vegetable-oil seeds. The oil is to be extracted with pumping supercritical carbon dioxide at a density of 500 kg/m3 through the packed bed. The estimated solubility of the oil in the dense gas at this density is 3.425 kg/m3. The superficial velocity of the carbon dioxide in the bed will be 1 mra/s. This fluid velocity is sufficiently small for the fluid to become saturated with oil. We are required to estimate the minimum time of operation for complete extraction of the oil from the bed. The initial oil fraction is 12% (wt/wt) based on wet seeds, the void fraction of the bed is 40%, and the density of the particles is 900 kg/m3. 

D.A. Moyler, CO2 extraction of essential oils Part III. pimento berry, coriander and celery seed oil, In Flavors and off-flavors, Developments in food science 24 (ed. G. Charalambous), Elsevier, Amsterdam, (1990) 263. 

Senkoylu and Dale (1999) reviewed the nutritional value of sunflower seed and meal for poultry. The seeds contain approximately 380g/kg oil, 170 g/ kg CP and 159g/kg CF and are a good source of dietary lipid. Sunflower meal is produced by extraction of the oil from sunflower seeds. The nutrient... 

Rhoeadine (R = CH3) was isolated for the first time by Hesse (665) in 1865. It has always been considered to be ineffective physiologically as well as poisonous. In children, the sedative and slightly expectorant effect of the syrup prepared from the flowers of P. rhoeas L. (where rhoeadine is the major alkaloid) could not be explained, nor can it be explained why cattle avoid P. rhoeas (666). Hakim (667) observed, after administration of seed oil and extracts from poppy heads of P. rhoeas, an increase in intraocular pressure in rabbits. Lieb and Scherf (372) administered rhoeadine to rabbits and found a significant decrease in intraocular pressure, mydriasis, and a slight stimulation of respiration. For details refer to Section II, N on the benzophenanthri-dine alkaloids. The increase in intraocular pressure is apparently not caused by rhoeadine. Awe (668) observed spasms after administration... 

Cumin oil is usually obtained by steam distillation of the milled spice hydrodiffusion gives a higher yield and, more recently, supercritical gaseous extraction is claimed to give oil closer to the aroma and taste of the spice (Eikani et al., 1999). The yields of cumin seed oil with steam distillation are 2.3-3.6%, with liquid carbon dioxide it is 4.5% and with ethanol it is 12%. The major components are cuminaldehyde, cuminyl alcohol, p-mentha and 1.3-dien-7-al, the minimum perceptible levels being at 0.2 ppm. Naik et al. (1989) reported that liquid C02 extraction was quicker than steam distillation for the quantitative extraction of cumin oil without loss of active flavour components, at 58 bar and 20°C. 

In summary, Foeniculum is stated to have three species, F. vulgare (fennel), F. azoricum Mill. (Florence fennel) and F. dulce (sweet fennel). Fennel is widely cultivated, both in its native habitat and elsewhere, for its edible, strongly flavoured leaves and seeds. The flavour is similar to, but milder than, that of anise and star anise. Anethole and fenchone are the major constituents of the solvent extract of seed phenols, free fatty acids, carbohydrates, proteins, vitamins and minerals have been reported in varying proportions. In the mature fruit, up to 95% of the essential oil is located in the fruit, greater amounts being found in the fully ripe fruit. Approximately 45 constituents have been determined from fennel seed oil, the main constituents being frans-anethole, fenchone, estragol (methyl chavicol), limonene, camphene, a-pinene and other monoterpenes, fenchyl alcohol and... 

Ajowan seed contains generally 8.9% moisture, 15.4% protein, 18.1% fat (ether extract), 11.9% crude fibre, 38.6% carbohydrates, 7.1% mineral matter, 1.42% calcium, 0.30% phosphorus and 14.6mg/100g iron, with a calorific value of 379.4 per 100g. The percentage of seed oil extracted with n-hex-ane is 31.80%, while that with ethanol is 28%. The neutral lipid component of the oil includes hydrocarbons, esters, sterol esters, triglycerides, free fatty acids, diglycerides, sterols and monoglycerides, whereas the polar lipid components are phosphatidyl ethanolamines and phosphatidyl cholines (Qasim and Khan, 2001). 

The extraction of seed with ether yields a dark green, fatty oil. The major fatty acid is oleic acid, which is followed by pet-roselinic acid. The fatty acid composition is indicated in Table 18.1. 

List, G. R. and Freidrich, J. P, Oxidative stability of seed oils extracted with supercritical carbon dioxide, J. Am. Oils Chem. Soc., 66, 98-101 (1989). 

Three factors, namely (1) irradiation power as a percentage, (2) irradiation time in seconds and (3) number of cycles, are used to study the focused microwave assisted Soxhlet extraction of olive oil seeds, the response measuring the percentage recovery, which is to be optimised. A central composite design is set up to perform the experiments. The results are as follows, using coded values of the variables ... 

The model I is very simple, and it is not very sensitive to the physical properties of the bed, but the values of the overall mass transfer coefficients optimised are strongly dependent from the equilibrium relation assumed and it only is able to describe the initial part of the extraction. Ke was determined by mass balance assuming a uniform distribution in solid bed. Ke values of 0.5, 0.2, and 0.6 were obtained for 7, 10 and 15 MPa. Assuming a = 3000 nAn", the mass transfer coefficients calculated with model I are of some orders of magnitude lower than those for external mass transfer coefficients. This type of models have being applied with success to the extraction of edible oils from seeds were the solute is in a... 

The extraction of sesame oil from roasted sesame seed is generally performed with pressing. Solvent extraction is not used because the desirable roasted flavor may be removed during evaporation of solvent. In commercial production, continuous screw-press or hydraulic press is employed (42). The hydraulic press can be vertical or horizontal. The continuous screw may be operated twice in order to increase the oil yield (82). Proper cooking (100°C, 7 min) and addition of water (12.5%) after roasting can also raise the oil yield (83). 

Leaching or solid-liquid extraction are terms that describe the extraction of soluble constituents from a solid or semisolid by means of suitable solvents. The process, which is used whenever tea or coffee is made, is an important stage in the production of many fine chemicals found naturally in animal and vegetable tissue. Examples are found in the extraction of fixed oils from seeds, in the preparation of alkaloids, such as strychnine from Nux vomica beans or quinine from Cinchona bark and in the isolation of enzymes, such as rennin, and hormones, such as insulin, from animal sources. In the past, a wider importance attended the process because the products of simple extraction procedures, known as galenicals, formed the major part of the ingredients used to fulfill a doctor s prescription. 

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