Oil cells

Such phase boundary potentials were already described in 1902 by Nernst and Riesenfeld 20) who investigated oil cells saturated with a common compound. A classical review of this research dealing with membrane potentials was published in 1922 by Michaelis 21). 

A second separation process reported by EBC is based on the use of hydrocyclones. Stable emulsions formed by good oil-cell-water contact and mixing can be separated continuously with hydrocyclones to obtain relatively clean oil and water. A method and an apparatus for separating a water/organic/solid emulsion, wherein the solid comprises particles having a length of about 50 xm or less, has been disclosed [267], This separation process scheme is shown in Fig. 14 and as before the separation method is envisioned as part of a BDS process. 

Features Stem erect, smooth, channeled, covered with exuded glaucous matter. Leaves alternate, twice pinnate. Flowers in June, terminal umbels. Fruits very small, compressed oval, marked on back in three ridges, with three dark lines (oil cells) between. Taste is distinctive, but recalls caraway. 

Features Rootbark is a bright, rusty brown, soft and brittle. Short, corky, layered fracture, with many oil cells. Chips of the woody root are commonly used—they are brownish-white in colour, showing concentric rings and slender medullary rays. 

Correct preparation is required for efficient crushing and for solvent extraction. Wherever possible, oilseeds should be dehulled before the oil is removed. This will increase the capacity of the processing equipment and avoid loss of oil that would otherwise be absorbed into the hulls. Oilseeds should be flaked, rolled, or ground, and dried to optimum moisture and temperature. Some oilseeds, especially those low in fiber or high in protein, should be cooked at elevated moisture for 15-20 minutes (to harden the protein) and then dried. Cooking and drying also ruptures the oil cells and reduces oil viscosity. This allows the oil to more easily drift from the solids and be extracted by the solvent. 

Size Reduction of Oilseeds. The extraction of oil from oilseeds, either by mechanical pressing or by solvent extraction, proceeds more efficiently if the seed is first flaked or ground. Opinion is divided whether grinding or flaking is more effective in rupturing the oil cells. Flaked oilseeds yield a large fraction of easily extractable oil on treatment with solvents and a smaller fraction (usually 10-30% of the total oil) that is difficult to extract (30, 31). The former fraction was presumed to come from ruptured oil cells. It has been shown (32), however, that some seeds (like... 

Moisture is present in all materials rendered or cooked and plays an important role in the cooking reactions. Without sufficient moisture, the desired cook would not be achieved. Water or steam or both are often added to elevate moisture and to ensure proper denaturing and hardening of protein, rupturing of oil cells, and inactivation of undesirable enzymes, micro-organisms, and antinutritional factors. Water also assists in the displacement of fat from the surfaces of solid materials. Solids have a greater physicochemical affinity for water than for fat. 

Some oilseeds are normally prepressed in screw-presses to mpture the oil cells and partially reduce the oil level. The cake from the screw-press is then cooled and either cmmbled and flaked or sent directly to a solvent extractor. The hot, tacky press-cake can also be formed into porous collets by extmsion. Enough steam is injected into the expander to raise the moisture 2-A percentage points. This allows the expander to transform the cake into porous collets. This must be done on stream, before the cake has had a chance to cool and harden. Once cool and hard, protein denatures, and the cake can no longer be transformed into a tacky, inflatable condition. 

A 203 mm (8 in.) diameter extruder, powered by a 112-kW (150-hp) motor, can process raw cracked soybean at up to 2722 kg/h (6000 Ib/h). The product, having low levels of urease and trypsin inhibitor, is marketable, without any further processing except cooling, as full-fat soymeal. However, the hot product, flashed down to 5-7% moisture, having almost all the oil cells ruptured, is ready to pass immediately to a screw-press. A conventional screw-press, with some modification to wormshaft configuration and rotational speed, can process this material at a threefold increase in capacity using the same motor and pressing to the same residual oil. 

An eight inch diameter expander, with 150 HP drive, can process preheated, cracked soybean at 60001bs/hr, producing full-fat soy with low levels of urease and trypsin inhibitor. Also, the hot product can pass into a screw-press (after its moisture is allowed to flash to 5-7%). As most of the oil cells have been ruptured by the expander, a screw-press can process the soybean at three times the capacity it would have had with unexpanded soybean. 

Oils and juices are obtained from plant sources by expression. Citrus essential oils are almost exclusively obtained by this method. Thoroughly washed unripe citrus fruits are cold pressed manually, or mechanically, to rupture oil cells in the rind. The oil is collected by draining and centrifuging. Manual operation is labor intensive and has been replaced by machines. 

Essential oils occur in plants in specially developed organs of various kinds, e.g. glandular hairs on leaves, stems and flowers. Secretory ducts or cavities (schizogenous or lysigenous) or oil cells may also be present in the plant tissue. 

Extraction recovery can be limited by one step or several steps. Microwaves cause more damage and destroy the essential oil cells in leaves or seeds more rapidly and effectively than conventional extraction methods, thus the desorption step, which can often be the limiting factor, is of minor importance in SEME. Solubility is rarely the limiting factor in solvent extraction if the solvent is well chosen. In the distillation of essential oils the solvent is always water, however, and aroma compounds can be totally different in structure and chemical characteristics, especially in their solubility. 

There are a number of different pathways by which organic chemicals may enter vegetation [95]. The major paAways include (1) uptake by roots and subsequent translocation from roots to shoots (i.e., liquid phase transfer) in the transpiration stream, (2) foUo uptake of volatilized organic chemicals from the surrounding air (i.e., vapor phase transfer), (3) uptake by external contamination of shoots by soil and dust, followed by retention in the cuticle or penetration through it, and (4) uptake and transport in oil cells which are found in oil containing plants Hke carrots and cress. 

Muresan, A., Ceremplel, A. Duncu, S., Muresan, R., and Butnaru, R. (2009). Aromatherpeutic charcteristics of cotton fabrics treated with rosmary essential oil. Cell. Chem. TechnoL, 43,435-442. 

Enzymatic enantioselective reduction of 2-octanone Fungal decolourisation of a waste sludge Technetium Tc (VII) reduction with E. coli cells Enzymatic production of mannitol and gluconic acid Enzymatic production of L-glutamate Enzymatic production of oligodextrans Lipolysis of olive oil Cell-free protein synthesis Enzymatic synthesis of aspartame precursor Enzymatic resolution of amino acids... 

Expanders. Sometimes low shear extruders called expanders are used. This equipment has the capability to process both low- and high-oil content materials. The meats are fed into an extruder after dehulling, flaking, and cooking and are heated as they are conveyed by a screw press through the extruder barrel. The meats are under considerable pressure and temperature when they reach the exit of the extruder. The change in pressure as the material leaves the extruder causes it to expand and the oil cells are ruptured, releasing the oil, which is rapidly reabsorbed. The expanded collets produced are then cooled and extracted with solvent. 

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