Vegetable oils, carotenoid extraction

Traditionally, dried or powdered plant material is used and extracts can be obtained by mixing the material with food-grade solvents like dichloromethane or acetone followed by washing, concentration, and solvent removal. The result is an oily product that may contain variable amounts of pheophytins and other chlorophyll degradation compounds usually accompanied by lipid-soluble substances like carotenoids (mainly lutein), carotenes, fats, waxes, and phospholipids, depending on the raw material and extraction techniques employed. This product is usually marketed as pheophytin after standardization with vegetable oils. 

Lipid-soluble food grade copper chlorophyll is manufactured similarly by extraction of adequate plant material, followed by replacement of magnesium by copper, and purihcation steps to remove carotenoids, waxes, sterols, oils, and other minor components that are co-extracted. Commercial copper chlorophylls may vary physically, ranging from viscous resins to fluid dilutions in edible oils as well as granulated forms and emulsions standardized with edible vegetable oil. Colors may vary... 

Dunaliella natural P-carotene is distributed widely in many different markets under three categories p-carotene extracts, Dunaliella powder for human use, dried Dunaliella for feed use. Extracted purified P-carotene is sold mostly in vegetable oil in bulk concentrations from 1 to 20% to color various food products and for personal use in soft gels usually containing 5 mg P-carotene per gel. Purified natural p-carotene is generally accompanied by the other Dunaliella carotenoids, primarily lutein, neoxanthin, zeaxan-thin, violaxanthin, cryptoxanthin, and a-carotene for a total of approximately 15% of carotene concentration. This compound is marketed as carotenoids mix. ... 

Use of cosolvent. Various cosolvents, such as acetone, ethanol, methanol, hexane, dichloromethane, and water, have been used for the removal of carotenoids using SC-CO2 extraction (Ollanketo and others 2001). All these cosolvents except water (only 2% of recovery) increased the carotenoid recovery. The use of vegetable oils such as hazelnut and canola oil as a cosolvent for the recovery of carotenoids from carrots and tomatoes have been reported (Sun and Temelli, 2006 Shi, 2001 Vasapollo and others 2004). For the extraction without cosolvent addition, the lycopene yield was below 10% for 2- to 5-hr extraction time, whereas in the presence of hazelnut oil, the lycopene yield increased to about 20% and 30% in 5 and 8 hr, respectively. The advantages of using vegetable oils as cosolvents are the higher extraction yield the elimination of organic solvent addition, which needs to be removed later and the enrichment of the oil with carotenoids that can be potentially used in a variety of product applications. 

Other carotenoids such as lycopene from tomato and its industrial waste [65-68] and lutein esters from marigold (Tagetes erecta) petals [69-71] had been extracted with supercritical fluids, achieving better extractiOT yields when modifiers and cosolvents were used as acetone, chloroform, ethanol, and vegetable oils. 

The membrane separation process was initially conducted in degumming vegetable oil and then was adapted for the recovery of carotenoids. Dense polymeric membranes are employed in this system and are very effective in the separatirm of xanthophylls, phospholipids, and chlorophyll, with retention of 80-100 %, producing an oil rich in carotenes [72,73]. This process, however, requires an additional step of hydrolysis or transesterification. Chiu, Coutinho, and Gruigalves examined the membrane technology as an alternative to concentrate carotenoids from crude palm oil in detriment of ethyl esters. A flat sheet polymeric membrane constituted by polyethersulfone was used and obtained a retention rate of 78.5 % [74]. Damoko and Cheryan obtained similar results using nanofiltration with 2.76 MPa and 40 °C in red palm methyl esters [75]. Whereas Tsui and Cheryan combined ultraiiltration with nanofiltration to separate zein and xanthophylls from ethanolic com extract [76]. 

Two samples of papaya oil extracted from dried papaya seed harvested in Somalia yielded 25-26% of an orange-yellow colored liquid with a smell of cress. The composition of fatty acid was similar to other reported values. The relatively high polyphenol content (2.5% in seed oil) gives the seed oil excellent stability to oxidation. The phosphatides are low while the carotenoids are significant (lOmg/lOOg). Unlike the majority of vegetable oils, the terpenic alcohols constituted the most abundant fraction found in the unsaponifiable fraction (Strocchi et al., 1977). 

Carotenoids are 40-carbon compounds made up of eight isoprene units. Carotenoids serve as light absorbing molecules in photosynthesis and also protect certain tissues from the deleterious effects of light. Beta-carotene is the precursor of vitamin A (which does not occur in plants). Beta-carotene occurs abundantly in the liver oils of fish and is extracted from that matrix commercially. Nutritionists recommend tomatoes, carrots, and green vegetables in daily quantities in order that carotenoids can be converted into vitamin A, a compound necessary for vision and other vital functions. 

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