Lauric oils

A USDA report indicates that between 1967 and 1988, butter consumption remained stable at 2 kg per capita, margarine dropped from 5.1 to 4.7 kg, and measured total fat intake per day dropped from 84.6 to 73.3 g (14). This study also projects that the reduced consumption of tropical oils is only temporary and will return to former use levels, possibly even higher. One reason for this projected rise in tropical oil consumption is the knowledge of the beneficial effects of medium-chain length acids high in lauric oils. There is a keen interest in omega-3 fatty acids, as well as linoleic acid, contained in fish oils. 

Fats and oils may be synthesized in enantiomerically pure forms in the laboratory (30) or derived from vegetable sources (mainly from nuts, beans, and seeds), animal depot fats, fish, or marine mammals. Oils obtained from other sources differ markedly in their fatty acid distribution. Table 2 shows compositions for a wide variety of oils. One variation in composition is the chain length of the fatty acid. Butterfat, for example, has a fairly high concentration of short- and medium-chain saturated fatty acids. Oils derived from cuphea are also a rich source of capric acid which is considered to be medium in chain length (32). Palm kernel and coconut oils are known as lauric oils because of their high content of C-12 saturated fatty acid (lauric acid). Rapeseed oil, on the other hand, has a fairly high concentration of long-chain (C-20 and C-22) fatty acids. 

Oleochemical-based alcohols are generally produced from either coconut or palm kernel oils. These lauric oils have carbon chain distributions in the C12-C14 range, where detergency performance is optimum. Figure 1 summarizes the... 

For at least the next 25 years enough lauril (natural C12-C14) oil will not be available to replace petrochemical-based surfactants even if this were desired. However, the oleochemical share of the surfactant intermediate market will grow because a large portion of excess lauric oil (coconut and palm kernel) will be designated for the surfactant market and used to supply the fatty alcohol capacity that has been announced for startup in the coming years. 

Most commodity oils contain fatty acids with chain lengths between Cie and C22, with Cig fatty acids dominating in most plant oils. Palm kernel and coconut, sources of medium-chain fatty acids, are referred to as lauric oils. Animal fats have a wider range of chain length, and high erucic varieties of rape are rich in this C22 monoene acid. Potential new oil crops with unusual unsaturation or additional functionahty are under development. Compilations of the fatty acid composition of oils and fats (6, 9, 11, 12) and less-common fatty acids (13) are available. 

In the de novo pathway, acetate and malonate react through a series of steps converting acetate first to butanoate (C4), then to hexanoate (Cg), and then sequentially, two carbon atoms at a time, to palmitate (Cig). At this stage, a thioesterase liberates the acyl chain from ACP. The thioesterase is not completely specific, and acids of other chain lengths may be produced. This is obviously true in the lauric oils where the specificity of their thioesterases causes lauric acid (12 0) to be the major saturated acid, accompanied by lower levels of caprylic (8 0), capric (10 0), myristic (14 0), and palmitic acid (16 0). 

The term tropical oils is correctly applied to oils and fats produced in the tropics and refers particularly to the (highly saturated) lauric oils (Sections 5.3 and 5.10) and to palm oil (Section 5.9). This term is frequently and unfairly used in a derogatory sense, partly through ignorance about the difference in fatty acid composition and use between lauric oils and palm oil and of the considerable nutritional value of the latter. 

Laurie Oils There are two major lauric oils—coconut oil and palm-kernel oil. Both are tropical oils, and both are tree crops. They differ from all other commodity oils in their higher level of medium chain acids, especially lauric, and slightly from one another as shown in Table 2(b). They find limited use in food products and are used extensively in the production of surface-active compounds. For more information, see Sections 5.3 and 5.10. 

Coconut oil from the coconut palm Cocus nuciferd) is one of two important lauric oils (see also pahn-kemel oil. Section 5.10). Annual production exceeds 3 million tons and comes mainly from Indonesia and the Philippines (Section 10). It is characterized by its high level of lauric acid (12 0) accompanied by the 8 0-14 0 acids. A detailed fatty acid composition of this oil is given in Table 2(b). The oil is used in the food industry and in the nonfood industry. In the latter case, it is used mainly as derivatives of the corresponding alcohols (dodecanol or coco alcohol). 

Palm-kernel oil is produced from the kernels of the oil palm, usually by solvent extraction and is an important lauric oil (see also coconut oil. Section 5.3). Its fatty acid composition is detailed in Table 2(b). Annual production is about 2.3 million tons. The kernels originate mainly in the oil palm growing areas of Malaysia and Indonesia and are crushed almost entirely in the country of origin (28, 29). 

Cuphea. Cuphea plants furnish seeds with oils that may be rich in Cg, Cjo, C12, or Ci4 acids. They generally contain >30% of oil and are expected to produce a commercial crop in the period 2005-2010. Problems of seed dormancy and seed shattering have already been solved. As markets for lauric oils already exist, there should be no difficulty in substituting cuphea oUs. More recently, it has been reported that cuphea will be used as a commercial source of lauric acid from 2003 onward (30, 102, 103). Pandey et al. (104) have described the oil (17-29%) from Cupea procumbens containing 89-95% of decanoic acid. See also Section 9.2. 

Dry fractionation is a two-step operation involving crystallization that should be allowed to proceed slowly to the equilibrium state, followed by hltration of the solid from the liquid phase. Crystallization occurs over several hours and requires good temperature control. The temperature must be lowered at a hxed rate to the selected value, and this must be combined with efficient but slow agitation. Good filtration—aiming at complete separation of solid and liquid—is important and may be carried out under reduced pressure using a Florentine hlter or under pressures up to 5 Mpa (50 bar) with a membrane hlter. Fractionation is applied mainly to palm oil but also to lauric oils (coconut and palmkemel), butter oil, beef tallow, hardened soybean, and cottonseed oil. 

Coconut oil belongs to unique group of vegetable oils called lauric oils. The most abundant fatty acid in this group is lauric acid, CH3(CH2)ioCOOH. Other sources of lauric oils are palm kernel, babassu, cohune, and cuphea. 

The various triacylglycerol (TAG) components of coconut oil may be separated and quantified by gas chromatography with the use of stable silicon gum stationary phase under temperature-programed conditions and identified by reference to standard TAG solutions. The carbon number of a TAG component is the sum of carbon atoms of the fatty acids attached to the glycerol moiety. For example, the carbon numbers of trilaurin and oleodistearin are 36 and 54, respectively. The relative amounts of each TAG in a sample of fat serves to establish its identity. For coconut oil, this test may also serve to distinguish it from other lauric oils (see Table 4 and Figure 5). 

Raw Materials for Oieochemicais. Oieochemicais or derivatives based on C12-C14 and C16-C18 chain lengths have a variety of uses. Tallow and coconut oil have been the traditional raw materials used for the production of C16-C18 and C12-C14 chain lengths, respectively. While tallow is produced by the developed countries such as the United States, the world has to rely on the Pacific region for the supply of lauric oils (C12-C14 source). The Philippines has been the main supplier of lauric oils. 

Palm-Based Oieochemicais. Palm kernel oil, like coconut oil, is a lauric oil. Its fatty acid composition is in fact very similar to that of coconut oil (Table 41). 

Some oils, like cottonseed oil, cannot be physically refined, as it requires an alkali treatment to remove the gossypol. For lauric oils and palm oil, on the other hand, physical refining is preferred in terms of both operating cost and refining loss. In the case of soybean and rapeseed oils, physical refining is suitable only for crude oils of a high quality, i.e., with a low degree of oxidation and a sufficiently low... 

Improvement of the deodorizer design by the installation of baffles and demisters in the vapor chimneys has significantly reduced entrainment losses to 0.1-0.2% in chemical refining. For steam refining, an additional loss directly proportional to the FFA content has to be taken into account. For most oils (soybean oil, pahn oil, etc.), NOL is exclusively due to mechanical carry-over. However, in lauric oils, part of the NOL is a consequence of effective evaporation of volatile short-chain mono- and diacylglycerols (30). (Table 13). This distillation loss of NOL is inherently due to the deodorization conditions, but is not affected by the deodorizer design. 

Coconut oil is commercially a major source of lauric acid. Together with pahn kernel oil and, to a small extent, babassu oil, it belongs to the so-called lauric oils, which are characterized by their high lauric oil content of approximately 50%. 

The lauric oils are highly desirable materials in the oleochemical industry worldwide because of the importance of the lauric fraction especially in the manufacture of soaps and detergents (4). 

Fatty alcohols can be produced from natural oils, or synthesized from petrochemicals. The current world supply of fatty alcohols is equally divided between natural and synthetic. However, the use ratio of natural synthetics varies with each region. The overall world ratio is projected to go in favor of natural fatty alcohols. This can be attributed to the increasing supply and price stability of the lauric oils. The primary source of lauric oil is in the Southeast Asian region where most processing plants have been established. 

Coconut oil (Table 1.14) has a very uneven record in terms of its production. This is a consequence of climatic and political instability in the countries where it is produced. Production at 3.4 million tonnes is mainly in the Philippines (43%), Indonesia (23%) and India (13%). The Philippines and Indonesia are the major exporters, while EU-15 and the US are the major importers. Coconut oil is an important lauric oil with significant food and non-food uses. It competes with palmkemel oil as the other major lauric oil. 

Oleochemical demands. This book is concerned with the source and composition of vegetable oils for use in the food industry, but it must not be forgotten that some 14% of total oils and fats are used in the oleochemical industry. The fats most in demand for this purpose (including some that are not considered in this book) are the two lauric oils (coconut and palmkemel), tallow, palm (especially palm stearin), linseed and castor. In addition, most vegetable oils find some... 

The lauric oils stand apart in the world of oils and fats. There are few of them, they move on their own higher price plateau and they do not mix comfortably with the common commodity oils and fats. There are only two lauric oils among the 17 major oils and fats in world commerce coconut oil (CNO) and palmkernel oil (PKO) (Oil World Annual 2001). They are called laurics because lauric acid (12 0) is the major fatty acid in these oils. The laurics are comprised of about 50% of lauric acid, while no other oil contains more than 1% (except butter fat, which contains about 3%). 

Of course, there are other lauric oils in local production—for example, babassu, tukum, murumuru, ouricuri, cohume and cuphea—but they are available only in small quantities and do not enter international trade. This chapter deals with CNO and PKO and, in particular, with those aspects of their composition and properties which significantly influence their processing or utilisation in the food industry. Their food applications are very similar and so, to avoid repetition, are dealt with together under palmkernel oil. 

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