Alcohol, carotenoid extraction

Preparation of carotenoid extract from plant oleoresin and hydrolysis with alkahne reagent in polar organic solvents (ether, polyhydroxyl alcohol, and ether alcohol)... 

Com endosperm oil—A reddish brown Hquid composed chiefly of glycerides, fatty acids, sitosterols, and carotenoid pigments obtained by isopropyl alcohol and hexane extraction from the gluten fraction of yellow com grain. 

Chlorophyll. Chemically pure chlorophyll is difficult to prepare, since it occurs mixed with other colored substances such as carotenoids. Commercially it is solvent extracted from the dried leaves of various plants such as broccoli or spinach. Chlorophyll is water-iosoluble. It has none of the characteristics of a dye in that it has no aflinity for the usual libers such as cotton or wool. Chlorophyll is properly classified as a pigment tCI Natural Green 3 Cl 75810), As such. It finds use lor coloring soaps, waxes, inks. fats, or nils. Chlorophyll is an ester composed of an acidic pint, chlorophyllin, esterilied by an aliphatic alcohol known as phylol. Hydrolysis of chlorophyll using sodium hydroxide produces the moderately water-soluble sodium salts of chlorophyllin. phytol. and methanol. The magnesium in chlorophyllin may be replaced by copper. The sodium copper chlorophyllin salt is heat-stable, and is ideal for coloring foods where heat is involved, such as in canning. 

Phenolic compounds are generally extracted using various mixtures of water and alcohol. Anthocyanins are traditionally extracted in the flavylium cation form, with methanol-containing hydrochloric acid. For the acylated anthocyanins, it is necessary to replace the hydrochloric acid with a weaker acid, either formic or acetic acid. Lipids, carotenoids, and chlorophyll are removed from the water-alcohol extracts with hexane, chloroform, or petroleum ether. The defatted extracts may be analyzed directly or after a partitioning of the phenolics into ethyl acetate. 

From the rest of the minor constituents, carotenoids and chlorophylls are affected by the extraction system. Their level is higher in the oils obtained by centrifugation, because of the metallic crushers used in this system, which release more of the pigments. Aliphatic alcohols and waxes content may increase if the temperature of the paste is too high (Cert et al. 1999). 

A diverse array of sources and preparative procedures are available to obtain organic carotenoids. - Lutein may be extracted from the petals of the Mexican marigold (Tagetes erecta) (Fig. 7.32). [69] Since xanthophyils occur in Nature mostly as esters, and while the free alcohol form is advantageous for many applications, the extraction process with a hydrocarbon is often followed by a hydrolytic step. [63]... 

NPLC is most suitable for separation of nonionic and moderately polar compounds, especially for lipophilic samples that are too strongly retained by RPLC. Lipids differing in the number and position of double bonds, tocopherol, carotenoids, fat-soluble vitamins, and steroids in pharmaceuticals can be successfully separated by NPLC on silica gel or alumina columns. Mixed lipid classes in the extracts of animal or plant tissues can be analyzed on silica columns or on columns with bonded polyvinyl alcohol using complex solvent gradients. Gradient-elution... 

Saponification of the extracts is generally desirable to remove unwanted lipid materials. However, this step is omitted in the isolation of carotenol esters, since these are hydrolyzed by this procedure. It is also omitted in the isolation of carotenoids such as fucoxanthin and peridinin, which are alkali-labile. If acetone has been used in the initial extraction, it is essential that all traces be removed before saponification. The general procedure used involves dissolving the total lipid fraction in an alcoholic (ethanol or methanol) solution of potassium hydroxide. The mixture is then either heated for a short period of time while kept in the dark, or left in the dark at room temperature for 12-16 h. There has been considerable discussion of the merits of these two procedures. Which method is used is dependent on the nature of the samples being analyzed and the requirements of the analysis (Davies, 1976 Liaaen-Jensen, 1971). After saponification, water is added, and neutral lipids (the unsaponifiable fraction) are extracted with diethyl ether or hexane. Acidic carotenoids remain in the alkaline phase and are extracted with diethyl ether or hexane after acidification with acetic acid. The unsaponifiable fraction usually contains sterols as well as carotenoids. If desired, sterol contaminants can be removed by precipitation from cold (- 10°C) petroleum ether or by precipitation of these compounds as their digitonides. 

Fruits obtained from this species of palm are very rich in fats, including oleic, lauric, myristic, capric, palmitic, stearic (all saturated) and linoleic fatty acids as well as ethyl esters of these fatty acids. The lipophilic constituents also include numerous sterols, diterpenes, sesquiterpenes, triterpenes, carotenoids and high-molecular-weight alcohols (Winston 1999). Water-soluble polysaccharides with high molecular weights are also found in the seed, but not in the widely used liposterolic extracts. 

Some natural complex matrices do not need sample preparation prior to GC analysis, for example, essential oils. The latter generally contain only volatile components, since their preparation is performed by SD. Citrus oils, extracted by cold-pressing machines, are an exception, containing more than 200 volatile and nonvolatile components. The volatile fraction represents 90-99% of the entire oil, and is represented by mono- and sesquiterpene hydrocarbons and their oxygenated derivatives, along with aliphatic aldehydes, alcohols, and esters the nonvolatile fraction, constituting 1-10% of the oil, is represented mainly by hydrocarbons, fatty acids, sterols, carotenoids, waxes, and oxygen heterocyclic compounds (coumarins, psoralens, and polymethoxylated flavones—PMFs) [92]. 

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). 

A system containing 20% of a tertiary alcohol in petroleum ether separated all the investigated pigments except -carotene and lycopene. A typical separation is shown in Fig. 12, where an extract from parsley was used as the carotenoid source, and the efficient spread of the polar pigments is evident. The separations are even better on plastic-backed silica gel (0.2 mm, Merck), where extremely narrow bandwidth can be produced. Combined with circular TLC, the system provides valuable information about samples with complicated pigment patterns in the polar area. 

Carotenoid pigments were extracted by chloroform-acetone-isopropyl alcohol /2 l l/ after acetone extraction as described earlier. Lipids of different parts were extracted and their fatty acid composition were analysed by GLC. Tocopherols of different parts of the fruits were extracted, saponified and prepared for HPLC analysis according to Speek and co-workers. Organic acids were prepared by a method described previously. Following preparation the samples were redissolved in a minimal volume of the HPLC eluent. 

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