Melting points, fats cocoa butter

The reactivity and nutritional value of a particular TAG depend on stereospecific isomerism. If a particular TAG composition is undesirable, it is possible to randomize the product, most often by treatment with alkaline catalysts. In a randomized fat or oil, the distribution of FA among TAG species is quite random. The randomization is particularly important in solid fats because the melting interval and the texture are changed for example, the melting point of cocoa butter increases from 34.8 to 54.2°C during the randomization. 

Cocoa butter NF is defined as the fat obtained from the seed of Theobroma Cacao Linne (Family Sterculiaceae) (44). Cocoa butter softens at 30°C and melts at 34°C. It contains four different forms alpha, beta, beta prime, and gamma with melting points of 22°C, 34°C to 35°C, 28°C and 18°C, respectively. The beta form is the most stable and is desired for suppositories. The biggest challenge with the polymorphism of cocoa butter is the impact of the manufacturing process on the characteristics of the suppository itself. When cocoa butter is hastily melted at a temperature greatly exceeding the minimum required temperature and then quickly chilled, the result is metastable crystalline form (a crystals), which may not even... 

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 complexity of chocolate manufacture arises from the polymorphic nature of its constituent fats, which can come in at least five crystal forms, each with an individual melting point. Cocoa butter is chemically a multicomponent mixture of triglycerides and trace compounds (Davis and Dimick 1986). Approximately 85% of the composition consists of just three triglycerides POP ( 20%), POS ( 40%) and SOS ( 25%), where palmitic (P), oleic (O) and stearic (S) are the fatty acids attached to the glycerol base. The precise composition depends on factors such as growing conditions and therefore can vary between batches, especially from different geographic regions (Chaiseri and Dimick 1989). 

Additionally, more than one subtype within the main polymorphic grouping has been identified in some fats. For example, six different polymorphic forms have been identified in cocoa butter, although there is stiU some debate whether they are all truly unique polymorphs (Table 2). Two p and two p forms have been identified for cocoa butter. These polymorphs have slightly different melting points, but they have X-ray spectra that fit within the definition of that polymorph. 

Nucleation of fats may either be enhanced or inhibited by the presence of these minor components. Dimick (57) has argued that the phospholipids in cocoa butter, with higher melting point than the cocoa butter TAG, crystallize first and subsequently catalyze formation of cocoa butter TAG. The appearance and chemical composition of cocoa butter crystals formed from refined cocoa butter (phospholipids removed) was different from that of the initial crystals formed in nonrefined cocoa butter. Recent studies where these minor components have been separated and then added back to the purified TAG have shown that they invariably inhibit nucleation (21). 

Vegetable Butters Most fats/oils derived from vegetable sources are liquid, reflecting the unsaturated nature of most of their component acids. The few that are sohd (i.e., have melting points above ambient temperature) are known as butters. The best-known and most important member of this class is cocoa butter (Section 5.2), which is the major or only, fat component in chocolate. Others discussed in Section 6 include iUipe butter (Borneo tallow), kokum butter, mango kernel fat, sal fat, and shea butter. These along with palm oil are, in some countries, permitted replacements, in part, for cocoa butter in chocolate (20, 21). 

For soap making, the melting point of the fatty acids (titer value) is an important parameter (117). The titer value for peanut oil is lower than that for cottonseed oil (30-37°C), cocoa butter, and animal fats and oils (118) but is higher than that for corn (14-20°C) and/or linseed oil (19-21°C) (37). 

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) ... 

These fats represent two extremes. Many animal body fats have a melting pattern more or less comparable to milk fat. Some vegetable fats, like palm oil and coconut oil, behave like cocoa butter (here the word oil is a misnomer since the clear points are about 40 and 30°C, respectively). A third type includes most vegetable oils, like sunflower, soybean, and peanut oil, that contain a high proportion of polyunsaturated fatty acid residues marine oils also are in this category. They generally have clear points in the range —5 to 5°C. 

These are fats rich in symmetrical disaturated TAGs which behave like cocoa butter in all respects, and are able to mix in all proportions with cocoa butter. The desirable characteristics of cocoa butter are due to the SOS TAGs (S = saturated) which provide suitable melting point and solid fat content to give rapid melt in the mouth and cooling sensations. Palm mid-fraction (PMF), which has high contents of POP, is easily formulated with other SOS fats for chocolate products (Berger 1981). About 70%-80% PMF with 20%-30% shea or sal stearin, or 60%-65% PMF with 20%-30% shea or sal stearin and 15%-20% illipe are suitable for plain and for milk chocolate with 15% milkfat. Compatibility of cocoa butter (CB) and CBE is affected by addition of milkfat and its fractions into the product (Sabariah etal. 1998). Eutectic interactions between anhydrous milkfat (AMF), CBE and CB were noticeable due to different polymorphism encountered in these fats. 

Even after full hydrogenation, the melting point of PKO does not rise much above mouth temperature and fractionation gives a stearin (PKOs) with even sharper melting. Fats melting sharply just below mouth temperature leave a clean, cool, non-greasy sensation on the palate, impossible for any of the common non-lauric oils to match. Cocoa butter is the only other natural fat with... 

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. 

Cocoa butter substitutes are prepared by separating out a middle melting fraction from palm oil and blending the resulting product with other exotic tropical fats. These fats are called palm mid-fractions. The slip melting points and iodine values of a few such fats are also plotted in Fig. 8.2 for added interest. It is unlikely that palm oil will ever be adulterated or contaminated with a palm mid-fraction as these fractions command a high price and are traded separately from the conventional bulk oils. 

Cocoa butter (Cacao oleum) is a solid fat, pressed from the roasted seeds of Theobroma cacao. Since the middle of the eighteenth century it is used as a suppository base. Cocoa butter melts at body temperature. At room temperature it is a solid mass. But cocoa butter has a number of undesirable properties it soon becomes rancid on storage and it exhibits marked polymorphism. It has four polymorphic forms alfa, beta, beta-accent and gamma. The melting points are 22 °C,... 

Cocoa butter or Theobroma oil is an edible vegetable fat obtained by hydraulic pressing of whole cocoa seeds or broken nibs [31]. This fat is widely used in cosmetics, pharmaceutical products, and in chocolate products. The melting point is near to 37 °C. The fat market is still demanding for this fat, and the fat content, which may exceed 50 % of dry bean weight, is an important breeding aim [32]. 

The dry mango stone consists of a 1 1 ratio of shell and kernel. Wide variations were found in the content, characteristics and composition of seed and fat of 43 varieties of mango fruit. The seed in fruit ranges between 3 and 25% and kernel in seed from 54 to 85% on an as is basis (Lakshminarayana et al., 1983). The total lipid consists of 96.1% neutral and 3.9% polar lipids (2.9% glycolipids and 1.0% phospholipids) (Hemavathy et al., 1987). The dry mango kernel from India contains 3.7-13% of a cream-colored oil with a melting point of 34-43 C and iodine value of 32-57. Its physical and chemical characteristics are very similar to that of cocoa butter. 

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