Cocoa melting property

When interesterification of milk fat was carried out at 100°C with 0.2% sodium, there was an increase in middle-melting point triacylglycerols but only small effects on the melting properties of milk fat (Timms and Parekh, 1980). These authors concluded that although the interesterified milk fat was more compatible with cocoa butter than unmodified milk fat, the effects were not sufficient to warrant the use of interesterification (Timms and Parekh, 1980). 

The physical properties of PKOs resemble particularly closely those of cocoa butter, and it is generally acknowledged that the best types of CBS are made from this fat. Substantial quantities of PKO are therefore fractionated in Western Europe, the US and Malaysia for this purpose. Coconut stearin, on the other hand, while having exceptionally sharp melting properties and mouth feel, has a melting point which is too low for substitute chocolate and most coatings. It is also obtained in lower yield and so is more costly to produce. Its uses, therefore, are restricted to the finest biscuit creams and a small number of luxury products. 

Composition and Properties. Cocoa butter is a unique fat with specific melting characteristics. It is a soHd at room temperature (20°C), starts to soften around 30°C, and melts completely just below body temperature. Its distinct melting characteristic makes cocoa butter the preferred fat for chocolate products. 

Cocoa butter has the desired "melt in the mouth property and is of high commercial value in comparison with palm oil. On the other hand, palm oil is more abundant than cocoa butter. The question is, can we convert palm oil to a product which has the desired properties of cocoa butter The answer is yes, by using lipases. 

Cocoa butter (CB) has a challenging chemistry and has attracted many efforts to develop lower cost, acceptable alternatives. The following definitions provide a quick introduction to this field (1) cocoa butter equivalents (CBEs) are compounded mostly from tropical oils other than palm. Because their melting and crystallization properties closely resemble CB, they are compatible as diluents at all levels of substitution (2) cocoa butter replacers (CBRs) are made from nondairy oils (typically soybean, cottonseed, or palm) partially hydrogenated for maximum trans-CIS isomer formation to acquire a steep melting profile. They are best used for enrobing bakery products, but their melting profiles can be improved by chill fractionation and (3) cocoa butter substitutes (CBSs) are made primarily from... 

The addition of milkfat to cocoa butter (4) results in marked lowering of the melting point, adversely affecting the crystallization behavior and the hardness as shown in Table 8. An obvious decrease is clearly evident in the solid fat content and a deterioration in solidification properties as shown in the values of the Jensen curve. These results are further confirmed by comparing the curves for milkfat and cocoa butter in various proportions. There are two reasons for this strong decrease in hardness (5, 6) ... 

Interesterification procedures are used industrially to improve the physical properties of lard, to produce cocoa butter substitutes from cheaper oils (usually combined with hydrogenation and fractionation), to produce fats containing acetic acid, and to produce margarine of appropriate melting behaviour with a minimum content of trans acids and maximum content of polyene acids. This has been achieved, for example, by interesterification of soybean oil (80%) and fully hydrogenated soybean oil (20%). 

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