High-melting glycerides

Parodi, P. W. 1974A. The composition of a high melting glyceride fraction from milk fat. Aust. J. Dairy Sci. 29, 20-22. 

Vasic, J. and DeMan, J. M. 1966. High melting glycerides and the milk fat globule membrane. Proc. 17th Int. Dairy Congr. C, 167-172. 

In addition to wax removal, rice bran oil contains sufficient saturated and high melting glycerides to require winterization to gain a cold test of 5 hours (8,43). Without winterization, dewaxed rice oil is frequently cloudy or turbid even at room temperature or slightly lower. 

The TAG 54 levels in the high melting glycerides of some shortenings and their polymorphic forms are listed in Table 16. Products with TAG 54 levels in the high-melting glycerides of less than 25% are P stable. This is usually achieved by incor-... 

TAG Carbon Number Composition (%) of the High-Melting Glycerides of (HMG) Stick Margarines and Their Polymorphic Form ... 

The distribution of fatty acids in the TAG of natural fats also determines dieir polymorphic behavior and, therefore, the texture of these fats. This is exemplified by the difference between lard and tallow (Table 17). Lard has none of the symmetric SUS glycerides, whereas in tallow there is 21%. The result (Table 18) indicates that lard crystallizes in the P form and tallow in die P form. The levels of TAG 54 and 16 0 in the high-melting glycerides of these fats are roughly similar. 

D Souza, V., L. deMan, and J.M. deMan, Chemical and Physical Properties of the High-Melting Glyceride Fraction of Commercial Margarines, Ibid. 68 153-162 (1991). 

D Souza, V., DeMan, L. and DeMan, J.M. (1991) Chemical and physical properties of the high melting glyceride fractions of commercial margarines. J. Am. Oil Chem. Soc., 68, 153-162. 

Many of the tests described involve physical properties such as refractive index, viscosity or melting point of the fat, of the fatty acids or of the lead salts of the fatty acids. However, there were also many chemical tests such as Reichert, Polenske, iodine, saponification and acetyl values. These all gave information as to the composition of the fat, some information as to fatty acid composition, others as to other non-glyceride components of the fat. Thus the iodine value is a measure of unsaturated fatty acids in the fat, now obtainable in more detail from a fatty acid profile. Similarly the Reichert value is a measure of volatile fatty acids soluble in water. For most purposes this means butyric acid, and so the modem equivalent is the determination of butyric acid in the oil. The modem method for milk-fat analysis is thus carrying out the analysis in a similar way to the Reichert determination, but uses a technique that is less dependent on the exact conditions of the analysis and is thus less likely to be subject to operator error. The Reichert value could be useful, in theory, even if milk fat was not present. Lewkowitsch notes that some other oils do give high values. Porpoise jaw oil has a value almost twice that of milk fat, while some other oils also have significant values. It is unlikely that one would have come across much porpoise jaw oil even in 1904, and even less likely today. 

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