Hydrogenated fats

Infrared spectra of fats and oils are similar regardless of their composition. The principal absorption seen is the carbonyl stretching peak which is virtually identical for all triglyceride oils. The most common appHcation of infrared spectroscopy is the determination of trans fatty acids occurring in a partially hydrogenated fat (58,59). Absorption at 965 - 975 cm is unique to the trans functionaHty. Near infrared spectroscopy has been utilized for simultaneous quantitation of fat, protein, and moisture in grain samples (60). The technique has also been reported to be useful for instmmental determination of iodine value (61). 

Nut Products. Peanut products iaclude peanut flour, Hpoproteia, proteia, milk, and partially defatted peanuts (109). Pecan butter is made from dry roasted meats, ground to a very fine state, and mixed with salt (2% of final weight), hydrogenated fat (1.5%), and the antioxidant butylated hydroxyanisole (BHA) (131). 

Double-bond migration often passes unnoticed, for unless tracers are employed, there may be no direct evidence remaining that migration has occurred. Nonetheless, the fact that it does occur can have a number of important consequences. Selective removal of cis homoconjugated dienes and trienes in natural oils, used to make edible hydrogenated fats, depends mainly on prior isomerization of multiple unsaturation into conjugation under hydrogenation conditions (J9). 

Bremer, J.W.J. Recovery of nickel catalysts from hydrogenated fats. US Patent (1959) 2,875,220. 

A.H. Lichtenstein, Trans fatty acids and hydrogenated fat, Nutrition Today, 1995, 30(3), 102-107. 

In the past various marine oils were used in biscuits but this practice had now ceased. Most biscuits contain vegetable fats. It was common to use hydrogenated fat in biscuits because vegetable oils were too soft physically and too unsaturated to be stable against oxidation. If an unsaturated fat is hydrogenated until it is completely saturated then a saturated fat results however, if it is only partially hydrogenated a partially hydrogenated fat with several double bonds is produced. 

Partially hydrogenated fats, 10 829 Partially hydrogenated oils, 10 813 Partially hydrolyzed trimethylaluminum (PHT), 16 88... 

Some of the unsaturated fats ingested by ruminants are partially hydrogenated by bacteria in the rumen. In consequence, milk fat, dairy products, as well as beef and mutton fat, also contain small amounts of trans isomers, about 2 to 9%. However, in fat from ruminants the main trans fatty acid is vaccenic (18 1 t 11), while in hydrogenated fats it is elaidic (18 1 t 9) (Figure 13.14). 

Recently new soaps have been found to improve greases with respect to melting point, adhesiveness, resistance to the washing action of water, and utility at both high and low temperatures. The newer thickeners are soaps of lithium 25) or barium 24) Certain properties of greases may be improved by saponification of the alkali with fats or fatty acids which have become available fairly recently these products include hydrogenated fats and pure fatty 13) acids such as 12-hydroxystearic acid. 

Catalytic hydrogenation of vegetable oils is widely used to form harder fats and to decrease the content of polyunsaturated fatty acyl groups. The products have a greatly increased resistance to rancidity. However, they also contain fats with trans double bonds as well as isomers with double bonds in unusual positions.251 253 Such compounds may interfere with normal fatty acid metabolism and also appear to affect serum lipoprotein levels adversely. Trans fatty acids are present in some foods. One hundred grams of butter contain 4-8 g, but hydrogenated fats often contain much more. It has been estimated that in the United States trans fatty acids account for 6-8% of total dietary fat.253... 

This unit describes the attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic method (AOCS, 1999a AOAC International, 2000), a novel method for measuring the total amount of fat with isolated trans double bonds. It is applicable to natural fats (ruminant fats) and processed fats and oils (partially hydrogenated fats and oils or refined vegetable oils) consisting of long-chain fatty acid methyl esters or triacylglycerols with trans levels >5%, as percent of total fat (AOAC International, 2000). 

In a partially hydrogenated fat, the number of fatty acid isomers is dramatically increased by the appearance of geometrical isomers (i.e., cis and trans configurations) and various positional isomers (i.e., different positions of double bonds within the fatty acid chain). Thus the in-... 

The importance of being able to determine the geometrical isomers of TGs in partially hydrogenated fats can be ascribed to their effect on the physical behavior of the fats, such as their polymorphic behavior and melting properties. 

With samples containing a wide range of components, such as hydrogenated fats, the column was eluted with solvent A for 13 min, then changed in one step to A-B (75 25), with a gradient to 100% B over 20 min. The free fatty acids were converted into the phenacyl derivatives and, prior to HPLC analysis, were purified by elution from a BOND ELUT NH2 column with hexane-diethyl ether (9 1). 

Although all-trans-octadecatrienoate tended to elute with the cis-dienes, this was not a problem in practice with samples of hydrogenated fats containing dienoic and trienoic fatty acids. A gradient elution scheme was adapted from the isocratic mobile phase used for monoenes and polyenes for the separation of such mixtures. 

The non-cocoa fats used in confectionery are mixtures known as cocoa butter alternatives (CBAs), of which the most important are cocoa butter equivalents (CBEs). These are formulated from non-hydrogenated fat fractions with a tri-acylglycerol composition almost identical with cocoa butter and which are miscible with cocoa butter in all proportions. Other alternative fats such as cocoa butter replacers (CBRs) and cocoa butter substitutes (CBSs) are used, particularly in the manufacture of specialized forms of chocolate application such as coatings. 

For industrial hydrogenation of vegetable and animal oils in Russia a Raney type nickel was prepared by Bag and co-workers (64). Preparation of detergents from hydrogenated fats has been reported (11). Reviews of these so-called skeleton catalysts were published by Russian investigators, for instance, by Lel chuk and co-workers (197). These catalysts have also been discussed with reference to hydrocarbon synthesis from water gas (148). Lel chuk (197) states that Raney nickel is more drastic for water gas synthesis than are the skeleton nickel catalysts prepared by Bag, and that Bag s copper-nickel skeleton catalysts approach nickel in their activity. Destructive hydrogenation under mild conditions was said to be possible with Bag s skeleton catalyst as described by Lel chuk. 

Mauger, J-F., Lichtenstein, A.H., Ausman, L.M., Jalbert, S.M., Jauhiainen, M., Ehnholm, C., Lamarche, B. 2003. Effect of different forms of dietary hydrogenated fats on LDL particle size. Am. 1. Clin. Nutr. 78, 370-375. 

A flow sheet for a semi-continuous interesterification line with postbleaching ability is shown in Fig. 34.27. The oil must be degummed, well-refined (<0.05 percent FFA), and free from peroxides and moisture that causes production of soaps. Palm oil stearin and completely saturated (<5 IV) Cl 8 hydrogenated fats generally are trans free and may be used as part of the feed. Reactions are run under vacuum, and oil is best stored under nitrogen between processes.44... 

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