Linoleic acid cocoa

The quantity of fat from the cocoa shell that ends up in the cocoa butter can be measured by testing with p-dimethyl-aminobenzaldehyde, which reacts with dried fruit pulp adhering to the shell. The reaction gives an intense fluorescence and has been used with TLC and fluorescence spectrophotometry (Kleinert, 1964). Shell fat is softer than nib fat because it contains higher levels of linoleic acid (18 2) and its presence softens the butter (Timms and Stewart, 1999). However, its presence can be usually due to poor separation of shell from nib rather than direct adulteration. 

Linoleic acid (LA or 18 2n-6) An 18-carbon, two double-bond fatty acid. It is the most predominant PUFA in the Western diet. It is found in mayoimaise, salad dressings, and in the seeds and oils of most plants, with the exception of coconut, cocoa, and palm. Linoleic acid is metabolized into longer-chain fatty acids, such as arachidonic acid and gamma-linolenic acid, in animals through a process of chain elongation and desaturations. 

Theobroma Oil, Cacao butter cocoa butter From roasted seeds of Theobroma cacao L., Sterculiaceae. Constit, Chiefly glycerides of stearic, palmitic, oleic, ara-chidic, and linoleic acids. 

Cocoa butter (CB) is a highly valued ingredient primarily used in the confectionery industry due to its specific physical and chemical properties. CB is solid at room temperature (below 25 °C), and liquid at body temperature (—37 °C) [43], Furthermore, the predominant presence of symmetrical TAG, about 90 % of the TAG species in CB, is mainly responsible for the functionality of this fat [44], The major FAs of cocoa butter are palmitic acid (Cl6) 25-33.7 %, stearic acid (C18 0) 33.7-40.2 %, oleic acid (C18 l) 26.3-35 % and linoleic acid... 

Cocoa butter is a unique, simple fat containing mainly mono-unsaturated and di-unsaturated glycerides. It has a typical composition of 26% palmitic acid (16 0), 36% stearic acid (18 0), 33% oleic acid (18 1) and 3% linoleic acid (18 2), although there are slight variations in composition... 

The fatty acids that concern us from a dietary point of view range in length from Cjj to Cjg. The acids may contain one or more double bonds the presence of the double bonds lowers the melting point of the fat, because the chains pack less well. In the Cjg series (Figure 11.96), we can identify stearic acid (saturated, mainly found in animal fats but also in cocoa butter), oleic acid (one double bond, the triglyceride is the main constituent of olive oil) linoleic acid (two double bonds, one of the essential fatty acids that we must consume for good health, found in safflower, sunflower, and corn oil), and linolenic acid (three double bonds, another essential fatty acid, found in canola, soya, and walnuts). In this series (and related ones), the saturated fats are solids, whereas the unsaturated fats are liquids at room temperature. So in order to... 

Cocoa seeds contain 35-50% of oil (cocoa butter or theobroma oil), 1-4% theobromine and 0.2-0.5% caffeine, plus tannins and volatile oils. During fermentation and roasting, most of the theobromine from the kernel passes into the husk, which thus provides a convenient source of the alkaloid. Theobroma oil or cocoa butter is obtained by hot expression from the ground seeds as a whitish solid with a mild chocolate taste. It is a valuable formulation aid in pharmacy where it is used as a suppository base. It contains glycerides of oleic (35%), stearic (35%), palmitic (26%), and linoleic (3%) acids (see page 44). 

More than 300 compounds had been identified in cocoa volatiles, 10% of which were carbonyl compounds (59,60). Acetaldehyde, 2-methylpropanal, 3-methylbutanal, 2-methylbutanal, phenylacetaldhyde and propanal were products of Strecker degradation of alanine, valine, leucine, isoleucine, phenyl-acetaldehyde, and a-aminobutyric acid, respectively. Eckey (61) reported that raw cocoa beans contain about 50-55% fats, which consisted of palmitic (26.2%), stearic (34.4%), oleic (37.3%), and linoleic (2.1%) acids. During roasting cocoa beans these acids were oxidized and the following carbonyl compounds might be produced - oleic 2-propenal, butanal, valeraldehyde, hexanal, heptanal, octanal, nonanal, decanal, and 2-alkenals of Cg to C-q. Linoleic ethanal, propanal, pentanal, hexanal, 2-alkenals of to C q, 2,4-alkadienals of Cg to C-q, methyl ethyl ketone and hexen-1,6-dial. Carbonyl compounds play a major role in the formation of cocoa flavor components. 

Sal fat (Shorea robusta). This tree, which grows in Northern India, is felled for timber. Its seed oil is rich in stearic acid, and it can be used as a cocoa butter equivalent (CBE). The major acids are palmitic (2-8%), stearic (35 8%), oleic (35 2%), linoleic (2-3%), and arachidic acid (6-11%). Its major triacylglycerols are of the SUS type required of a cocoa butter equivalent. Sal olein is an excellent emolhent, and sal stearin, with POP 1%, POSt 13%, and StOSt 60%, is a superior cocoa butter equivalent (122-124). It is one of the six permitted fats (palm oil, iUipe butter, kokum butter, sal fat, shea butter, and mango kernel fat), which, in some countries at least, can partially replace cocoa butter in chocolate (86). 

In this work, Candida curvata, now renamed Apiotrichum curvatum (but see also Table 9.2), was mutated and auxotrophic mutants were isolated that required oleic acid to be added to the culture media to allow them to grow. Such mutants were then unable to synthesize oleic acid themselves and thus would presumably be devoid of A9-desaturase activity (Figure 9.5). One of the isolated mutants, Ufa 33 (Table 9.5), now contained 50% stearic acid residues in its lipid. Nevertheless, the added oleic acid was still being converted to linoleic and linolenic acids which are regarded as undesirable fatty acids in any potential cocoa butter equivalent. To remove the A12- and A15-desaturases would have required a further, and much more extensive, mutation programme. 

Today palm oil is widely used in food applicahons and preferred for frying and baking applications because of its good oxidative stability and high solid fat content. Palm oil contains about 50% saturated (42 8% palmitic and 4-5% stearic acids) and 50% unsaturated fatty acids (37-41% linoleic and 9-11% linolenic acids). The fatty acid composition of palm kernel oil resembles that of the coconut oil rather than that of palm oil. Palm kernel oil is rich in lauric (about 48%), myristic (16%) and oleic (15%) acids. Both palm oil and pahn kernel oil are commercially separated into stearin (solid) and olein (liquid) fractions for special applications. The stearin fraction obtained from palm kernel can be used as a cocoa butter substitute. The olein fraction is used in baked goods and soap manufacturing. Imitation palm-oil-based cheese, hand and body lotion, fatty acid methyl esters for use as fuel or solvent, and epoxidized pahn oil to produce plasticizers and stabilizers for conventional polyvinyl chloride plastics are some of the other products that are produced from palm oil (Basiron, 2005). 

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