Bleach solvent extraction

Rice-Bran Wax. Rice-bran wax [8016-60-2] is extracted from cmde rice-bran oil. It can be degummed, the fatty acid content reduced by solvent extraction, and bleached. The wax is primarily composed of esters of lignoceric acid (43 wt %), behenic acid (16 wt %), and 22 02 alcohols (28 wt %). Rice-bran wax may be used in some food apphcations under the regulations described in 21 CFR 172.890. 

Sulphur dioxide is used as a preservative for beer, wine and meats in the production of sulphites and hydrosulphites in solvent extraction of lubricating oils as a general bleaching agent for oils and foods in sulphite pulp manufacture in the cellulose and paper industries and for disinfection and fumigation. 

Corn Oil (Unhydrogenated) occurs as an amber-colored oil. It is obtained from the corn plant Zea mays (Fam. Gramineae), usually by solvent extraction of the corn germ. It is refined, bleached, and deodorized to substantially remove free fatty acids, phospholipids, color, odor and flavor components, and other non-oil materials. It is a liquid at 21° to 27°, but traces of wax, unless they are removed by winterization, may cause the oil to cloud when cooled to low temperature. It is free from visible foreign material (other than wax) at 21° to 27°. 

These same expellers, if employed in a prepressing mode wherein 15-17% residual oil remains in the cake that is sent to the solvent extraction unit, can process 45-501 of seed per day. Prepressing of safflower produced under Califomia conditions (or the equivalent) requires no cooking, flaking, or cracking of the seed before extraction and results in oil capable of being heat bleached to 1-3 Gardner color. 

Under the conditions of this study there was no need to extract Skeletonema at 31.0 HPa since there was negligible increase in the yield of oils that can be obtained from SC COj extraction at 24.0 MPa. However, an increase in pressure improved the yield of oils extracted from Ochromonas. Chlorophylls were not extracted by SC COj the bleaching procedure in conventional solvent extraction can be eliminated. Treatment with phospholipase C improved the yield slightly. 

One important trend in the food industry is the increased demand for natural food ingredients free of chemicals. Therefore, special attention has been paid to alternative processes directed toward extraction solvents and techniques with both GRAS and GMP labels (Ibanez et al., 1999). Supercritical C02-extraction (SFC C02) has been used (Weinreich, 1989 Nguyen et al., 1991 Nguyen et al., 1994 Ibanez et al., 1999). Tena et al. (1997) noted that extracts from rosemary obtained by SFC C02 (35 bar at 100°C) were the cleanest extracts and provided the highest recovery of carnosic acid compared to solvent extracts (acetone, hexane, dichlor-methane and methanol) after bleaching with active carbon. Bicchi et al. (2000) reported a fractionated SFC C02 method to selectively isolate carnosol and carnosic acid at 250 atm and 60°C in the second fraction. The authors used 5% methanol to modify the dissolution power of SFC C02. 

Derivation From seeds of the flax plant Linum usi-tatissimum by expression or solvent extraction. Various refining and bleaching methods are used. 

Derivation The free fatty acid is obtained from the glyceride by hydrolysis, steam distillation, and separation by crystallization or solvent extraction. Filtration from the press cake results in the oleic acid of commerce (red oil), which is purified and bleached for specific uses. 

The raw oil extracted from the husks is dark green, with high acidity and a bad flavour. It has to be neutralised, bleached, and deodorised before it is edible. Due to the solvent extraction, olive-residue oil contains some minor constituents at higher levels than those found in olive oils (waxes, sterols, erythrodiol and uvaol). This is the reason for designating pomace oil as a distinct product. 

Solvent Extraction with Oilseeds—Extraction of the bleaching earths in a mixture with oilseeds is practiced by some extraction plants with processing capabilities, but the potential problems for this type of recovery may outweigh the savings for example, the mineral content of the meal may be increased beyond the acceptable limits, and the recovered oil may decrease the quality of the new oil extracted. The oxidation products and polymers from the recovered oil could contaminate the fresh oil. 

Oil is extracted either by pressing or increasingly by solvent extraction. The crude oil has a strong characteristic flavour and odour and has a dark reddish brown colour. The free fatty acid content of the oil depends on the conditions of harvesting and moisture content of the seed good-quality oil has free fatty acid of 0.5-1%. Normally it is increasingly difficult to bleach the oil satisfactorily as the free fatty add of the crude oil increases. However, there is no direct relation between the quality of the crude oil and the stability and flavour of the fully refined oil. 

The small (5 mm long) oval flat seeds are usually pressed then solvent-extracted yielding crude linseed oil, which is dark amber in colour. The colour of the oil is improved by refining and bleaching. This also removes phosphatides. Waxes are removed from the refined oil by winterization. 

Miscella refining (Cavanagh, 1976) is a special case of continuous caustic soda refining. The most favourable conditions for the process are those of the solvent extraction plant where it is also desired to refine the oil and perhaps further process it by winterization. For this reason cottonseed is the oil most usually processed in this manner. The miscella from the extraction plant is evaporated to the desired oil hexane proportion, approximately 65 35 in the case of cottonseed oil. The corrected miscella is then pretreated with phosphoric acid, neutralized and the soapstock centrifugally separated as for the normal 100% oil process. Soapstock separation is very efficient and therefore the miscella does not need to be washed. The solvent is evaporated from the refined oil and the oil is bleached and deodorized. The process is capable of giving higher yields of refined oil and improved colour of the bleached oil by comparison with non-miscella refined oils. 

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