Triglycerides and their derivatives

The heterogeneous class of compounds marked by solubility in so-called lipid solvents (acetone, hydrocarbons, ether, etc.) and relative insolubility in water, has traditionally been called lipids (3). This historical classification, based upon isolation procedures from natural products, is obviously too broad for simple generalizations since it includes triglycerides, fatty acids, phospholipids, sterols, sterol esters, bile acids, waxes, hydrocarbons, fatty ethers and hydrocarbons. For the purposes of this chapter, we will consider lipids to be fatty acids and their derivatives. 

Native or hydrogenated palm, palm kernel, rapeseed, soya, pemiut, coconut, castor, cotton oils, cocoa butter and their derivatives (obtained by fractionation, esterification, concentration mid/or reconstitution fatty acids mid cohols, mono-, di- and triglycerides, cocoa butter substitutes, mmgmine, shortenings, acetylated glycerides, lecithins, etc)... 

Fig. 10.13. A sketch of the possible interactions of free fatty acids and their derivatives with brown fat mitochondria. The sketch illustrates some of the candidates for the mediator of thermogenesis (i.e., the substance or process that will activate thermogenin (alt. another site of the mitochondrial membrane) even in the presence of the inhibitory cytosohc nucleotides). Common for the candidates shown here is that they are formed subsequent to the activation of lipolysis of the stored triglycerides (TG) by norepinephrine (NE) via cAMP-dependent processes. The candidates illustrated are free fatty acids (FFA), interacting (1) with the purine-nucleotide binding site on thermogenin, (2) with another site on thermogenin, (3) with another protein than thermogenin, or (4) directly with the membrane, and the acyl-CoAs, interacting (5) specifically with the purine-nucleotide binding site on thermogenin, or (6) unspecifically with the membrane. For discussion, see Section 5.

The term lipid is frequently used to denote a wide variety of natural products fatty , oily or waxy substances of animal and vegetable origin that are easily soluble in organic solvents readily satisfy this loose definition. Thus, such diverse compounds as fatty acids and their derivatives, triglycerides, sterols, phosphatides and sphingolipids, carotenoids, bile acids, vitamins A, D, E, and K, long-chain alcohols, terpenes, etc., may be included. Studies of these substances by GC are indeed numerous a comprehensive survey of this field is beyond the scope of this... 

This chapter will start with a brief overview of SCF processing. Thereafter, a phase behaviour analysis of palmitic acid, methyl palmitate, ethyl palmitate and tripalmitin in CO2, ethane and propane, as well as CO2 together with a co-solvent will be considered. The analysis will investigate phase equilibrium data present in the literature, trends observed the data, a comparison between the phase behaviour of the various derivatives as well as the various solvents, and the effect of a co-solvent. The phase behaviour data will then be used to analyse how SCFF and SCFE can be used to obtain extracts enriched in palmitic acids or its derivatives. In particular this study will consider how SCFF can be used to distinguish between various fatty acids and their derivatives and also between palmitic acid and/or its derivatives and other components present in the sources. Finally, SCFE of palmitic acid containing triglycerides from solid matrices will be considered. The overarching aim of this chapter is thus to show how SCFs can be used to process palmitic acid and its derivatives. 

Before tackling the issues linked directly to macromolecular materials derived from plant oils, introduction to some basic notions related to the chemistry of triglycerides and their fatty-acid derivatives is crucial because they constitute the basic reactions that lead to monomers and polymers. 

Selective catalytic deoxygenation of fatty acids and their derivatives in the liquid phase has been demonstrated over Pd/C and Pt/C catalysts at temperature and pressure ranges of 543-633 K and 6-20 bar, respectively [7,11]. Several feedstocks such as saturated and unsaturated fatty adds and esters as well as triglycerides have been used. Furthermore, catalyst properties and reaction conditions [9,18] have been optimized, and the possibility of using either batch [20] or continuous reactors [15, 16, 21] has been demonstrated. 

Soap products in the United States are produced almost exclusively from tallow fat and coconut oil or their fatty acid derivatives. The utilization of palm oils, palm kernel oil, and their derivatives for soap manufacture is more commonly practiced in many other parts of the world, especially in Asia. Among other triglycerides cottonseed oil, ricebran oil, castor oil, neem oil, sunflowerseed oil, fish oil, and olive oil also have been used as indigenous feedstocks in many developing nations. The... 

A detailed classification of the chemical compounds usually employed was given by (Dubief et al., 2005). The most important of these are organic acids (carboxylic acids and aromatic sulphonic acids), fatty compounds and their derivatives (fatty acids, fatty alcohols, natural triglycerides, natural waxes, fatty esters, oxyethylenated and oxypropy-lenated waxes, partially sulphated fatty alcohols, lanolin and its derivatives, ceramides), vitamins (A, B and E) (see Section 8.6), protein derivatives (extracts or hydrolysates of keratin, collagen and vegetable proteins), silicones (dimethicone and others), cationic surfactants, cationic polymers, amphoteric and betainic polymers. 

The elution factors in normal-phase TLC and RP-HPLC, using a fixed set of chromatographic parameters, were determined for a series of saturated triacylglycerides with TCN from C30 to Ceo, serving as reference compounds and various oxidation derivatives of analogous unsaturated triglycerides, including hydroperoxides, peroxides, epoxides, core aldehydes and their DNP derivatives. From these measurements, a series of incremental... 

The ozonides of choline and ethanolamine phosphatides and triglycerides can be subjected to reduction with triphenylphosphine to yield the corresponding core aldehydes, and further derivatized to the 2,4-dinitrophenylhydrazones (DNP). The core aldehydes and their DNP derivatives can be separated by HPLC and characterized by various techniques, including EI-MS and TS-MS of positive and negative ions . See also Section VHI.E. 

Gemfibrozil is a fibric-acid derivative that decreases blood levels of triglycerides and VLDL by decreasing their production. It also decreases cholesterol and increases HDL. 

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