Specialty fats

Cocoa butter substitutes and equivalents differ greatly with respect to their method of manufacture, source of fats, and functionaHty they are produced by several physical and chemical processes (17,18). Cocoa butter substitutes are produced from lauric acid fats such as coconut, palm, and palm kernel oils by fractionation and hydrogenation from domestic fats such as soy, com, and cotton seed oils by selective hydrogenation or from palm kernel stearines by fractionation. Cocoa butter equivalents can be produced from palm kernel oil and other specialty fats such as shea and ilHpe by fractional crystallization from glycerol and selected fatty acids by direct chemical synthesis or from edible beef tallow by acetone crystallization. 

In many instances, TGs exist in polymorphic forms. Crystal structure is very important to the properties of margarines, shortenings, and specialty fats. The very unstable a form is readily transformed to the more stable ft form, which in some TGs has a higher melting point (more stable) than the /3 form. In single-acid TGs, the order is a — f3 — a, but some mixed TGs show a lower-melting (less stable) (3 form. This is further complicated by the existence of multiple / and /3 forms, depending upon the detailed TG structures at hand. 

Crude palm oil used to be the main form of export in the past. With the establishment of refineries especially in Malaysia during the mid-1970s and 1980s, refined palm oil products have replaced the crude as the main form of palm oil export. A wide range of processed or semiprocessed products are exported, and these include the different fractions of processed pahn oil known as palm olein (liquid) and palm stearin (solid). The availability of refineries also led to the production of specialty fats products aimed at the confectionery markets. A similar trend has been seen in the export of pahn kernel oil. Palm kernel oil is a coproduct to palm oil produced at a ratio of 10-13 tons of palm kernel oil for every 100 tons of palm oil. Even the export of refined palm kernel oil has begun to decline as more is being used locally by the oleochemical industry that has been estabhshed in recent years. 

Solvent Fractionation. This process is the most expensive because of solvent loss, solvent recovery equipment, much lower temperature requirement, and stringent safety features. The process involves the use of solvents such as hexane or acetone. The oil is first dissolved in the solvent followed by cooling to the desired temperatures to obtain the desired crystals. Cooling is effected by brine if very low temperature is required. The miscella containing the partially crystallized oil and solvent is then filtered under vacuum suction in an enclosed drum filter. The olein miscella and stearin miscella are then separately distilled to remove the solvent and recover the fractions. Yield of olein is about 80%. The solvent process nowadays is only viable in the production of high value products such as cocoa butter equivalent or other specialty fats. 

The use of palm oil in food dates back 5000 years. For edible and nonedible uses, palm oil is normally refined. However, even today, unrefined palm oil is still used for cooking in certain African villages much the same way as it used to be. Examples demonstrating the range of palm oil applications in food are shortening, margarine, vanaspati, deep frying fat, and specialty fats. 

Palm oil and palm kernel oil are also ideal raw materials for the production of specialty fats. Specialty fats are particularly suitable for confectionery products, especially chocolates. Specialty fats can be classified according to their chemical composition into three types (1) symmetrical, (2) lauric, and (3) high trans. 

Because of the similarity in the chemical compositions of the symmetrical-type fats and cocoa butter, they are compatible with each other in almost any proportions, and for this reason these specialty fats are usually called cocoa butter equivalents (105). In certain countries, legislation allows up to about 15% of the cocoa butter in chocolate to be replaced by symmetrical-type specialty fat and the product may still be described as chocolate. In terms of texture and flavor these products are very close to real (cocoa butter) chocolate. 

High-trans-type specialty fats can be produced by a combination of selective hydrogenation and fractionation from liquid oils. These high-trans-type fats can be produced by selectively hydrogenating blends of soybean oil and pahn olein or palm olein alone. They are more compatible with cocoa butter than the lauric-type cocoa butter substimtes, thus they are sometimes called cocoa butter partial replacers. 

CBEs are nonhydrogenated specialty fats containing the same fatty acids and symmetrical mono-unsaturated triacylglycerols as cocoa butter. They are fully compatible with cocoa butter and can be mixed with cocoa butter in any ratio in the chocolate formulations. 

Fractionation is designed to separate the various fractions based on differences in crystallizing temperatures. Often, the products of a single fractionation are not sufficiently fine tuned to produce some of the higher value specialty fats. Hence, the concept of double fractionation was introduced, with one of the phases (usually the olein) refractionated. This process is used quite frequently with palm oil. The products of the second fractionation are a super olein and a stearine used as tropical margarine base or a confectionery base. 

Dry fractionation applications have enjoyed substantial growth in the past years, and with growing emphasis on value-added specialty fats, the processor finds fractionation a most valuable tool. It is expected that rapid growth fractionation capacity will occur as processors search for additional revenue enhancement opportunities. 

Tan, B.K. (2001) Recent advances in modification techniques for specialty fats, presented at the PORIM International Palm Oil Conference on Cutting Edge Technologies for Sustained Competitiveness, 20-22, August, 2001, Kuala Lumpur. 

Goh EM (1993) Specialty fats from palm and palm kernel oils. Selected readings on palm oil and its uses. PORIM... 

This applies, of course, also for palm kernel oil (PKO), which is used either on its own or in combination with palm oil products in the manufacture of specialty fats. Incorporation of palm kernel oil or its derivatives, particularly in table margarine and spreads, improves the melting characteristic of the products. Non-food applications include soaps, which in Southeast Asia are primarily made from palm oil and PKO or coconut oil. A typical blend of soap noodles would be 80% palm oil and 20% PKO, giving about the right balance... 

Uses Specialty fat for ice cream coating Features Low m.p. economical flexible coating Isao 43-15 [Aarhus OliefabrikA/S]... 

Uses Specialty fat tor ice cream coating Features Light snap ready for dipping at R.T. 

Before considering the utilization of canola oil in the formulation of margarine base oils, shortenings and specialty fats, it should be pointed out that this oil has proved to be an excellent salad and cooking oil both for general household use and also in the commercial manufacture of mayonnaise, sandwich spreads, and liquid and spoonable" salad dressings. 

This principle has been exploited, with regard to 1,3 regio-specific lipases, in the production of specialty fats such as cocoa butter substitutes and equivalents (section 12.6). It is worth noting that lipases lacking specificity produce products similar to those produced by chemically catalysed interesterification as shown in Figure 12.6. 

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