Hardening of fats and oils

A significant application of hydrogen with a large-scale technological importance is in the food industry the hardening of fats and oils by catalytic hydrogenation for the purpose of extended durability. The process takes place at pressures of 20 - 40 MPa and at temperatures of 200 - 400 °C. 

Tacke, T., Wieland, S., and Panster, P., Hardening of fats and oils in supercritical CO2, Proc. of the 3rd Int. Symp. on High Pressure Chemical Engineering, Zurich, 1996. 

CY Tsang, WB Streett. Phase equilibria in the H2/CO2 system at temperatures from 220 to 290 K and pressures to 172 MPa. Chem Eng Sci 36 993-1000, 1981. T Tacke, S Wieland, P Panster. Hardening of fats and oils in supercritical CO2. In P Rudolf von Rohr, C Trepp, eds. Process Technology Proceedings. Vol. 12. High Pressure Chemical Engineering. Amsterdam Elsevier, 1996, pp 17-21. 

Lipids are constituents of plants and animals that are characteristically insoluble in water. Fats and oils are lipids that are triesters formed by reaction of the triol glycerol with long-chain saturated or unsaturated acids called fatty acids. The common acids in fats and oils have an even number of carbons (for example, stearic acid has 18 carbons), and, if unsaturated (for example, oleic acid), they have the Z configuration (Table 15.1 lists the fatty acids, with their common names). Hydrogenation of oils, which have a high percentage of unsaturated acids, converts them to solid fats in a process called hardening. 

Other (oxo synthesis, hydrogenation of organics, fat and oil hardening, metal oxide reduction) 10... 

Medical evidence correlates a diet high in saturated fats with hardening of the arteries (atherosclerosis) and possible heart attack. Table 22.2 lists the percentage of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in some common dietary fats and oils. This table compares human depot (storage) fat with butter and margarines, then with several vegetable oils. 

In contrast to fats and oils, fat powders have better stability against autoxidation and, in some food products such as dehydrated soup powders or broths, are easier to handle. They are manufactured from natural or hardened plant fats, sometimes with the addition of emulsifiers and protein carriers. Butter and cream powders are also produced. 

Timms, RE. (1978). The solubility of milk fat, fuUy hardened milk fat and milk fat hard fractions in liquid oils. Aust J Dairy Technol 33 130-135. 

Hardening of Fats. Fats that contain a large proportion of saturated fatty acids (there is always a variety of fatty acids in a fat) have a higher melting point and are solid at room temperature, whereas those fats with a high content of unsaturated fatty acids are liquid or oily (the term oil denotes consistency and not a... 

---