Fatty acids in butter

Smith et al. (1978) have described a procedure for the GLC determination of cis and trans isomers of unsaturated fatty acids in butter after fractionation of the saturated, monoenoic, dienoic, and polyenoic fatty acid methyl esters by argentation TLC. Total trans acids were much higher, as measured by infrared spectrophotometry than by GLC, probably because some of the acids could have two or more of the trans bonds designated as isolated by infrared spectrophotometry. Enzymatic evaluation of methylene-interrupted cis, cis double bonds by lipoxidase resulted in lower values than those obtained by GLC. The authors mention that the lipoxidase method is difficult, requiring considerable skill, and suggest that their method is suitable for the determination of the principal fatty acids in complex food lipids such as bovine milk fat. 

Iverson, J. L. and Sheppard, A. J. 1977. Butyl ester preparation for gas-liquid chromatographic determination of fatty acids in butter. J. Assn. Off. Anal. Chem. 60, 284-288. 

Smith, L. M., Dunkley, W. L., Franke, A. and Dairiki, T. 1978. Measurement of trans and other isomeric unsaturated fatty acids in butter and margarine. J. Am. Oil Chem. Soc. 55, 257-261. 

Iverson, J.L. and Sheppard, A.J. (1986) Determination of fatty acids in butter fat using temperature-programmed gas chromatography of the butyl esters. Food Chem., 21, 223-234. 

Reed, A.W., Deeth, H.C., Clegg, D.E. 1984. Liquid chromatographic method for quantitative detemination of free fatty acids in butter. J. Assoc. Off. Anal. Chem. 67, 718-721. 

Woo, A.H., Lindsay, R.C. 1980. Method for the routine quantitative gas chromatographic analysis of major free fatty acids in butter and cream. J. Dairy Sci. 63, 1058-1064. 

Biitikofer, U. 1996. Collaborative study on the determination of free fatty acids in butter and cheese. FAM Information 325PW, Agroscope, Berne. 

The great variety of fatty acids in butter fat cannot be treated in detail here reference will be made to only a few of the many available reports. Octadecadienoic acids are present in significant amounts there are traces of hexadecadienoic acid, octadecatrienoic acids, and highly unsaturated C20 and C22 acids. Traces of dUiy-droxystearic acid and hydroxypalmitic acid have been detected (8, 9). A small proportion of the octadecenoic acid consists, not of oleic acid, but of trans-l 1,12 isomer, vaccenic acid (8, 9). One report states that about 66% of one octadecienoic... 

The genuine butterfat content may be determined by GC or by determining the Reichert, Polenske, and Kirschner values for volatile fatty acids in butter. These are obtained by titration of various distillation fractions against O.lmoll sodium hydroxide. 

Table 3.24. Free fatty acids in butter (sweet cream) samples of different quality...

Oils, Nitrated. See under Fats, Fatty Oils, Tallows, Butters, Waxes and Fatty Acids in Vol 8, F8-L to F9-L... 

The common fatty acids have a linear chain containing an even number of carbon atoms, which reflects that the fatty acid chain is built up two carbon atoms at a time during biosynthesis. The structures and common names for several common fatty acids are provided in table 18.1. Fatty acids such as palmitic and stearic acids contain only carbon-carbon single bonds and are termed saturated. Other fatty acids such as oleic acid contain a single carbon-carbon double bond and are termed monounsaturated. Note that the geometry around this bond is cis, not trans. Oleic acid is found in high concentration in olive oil, which is low in saturated fatty acids. In fact, about 83% of all fatty acids in olive oil is oleic acid. Another 7% is linoleic acid. The remainder, only 10%, is saturated fatty acids. Butter, in contrast, contains about 25% oleic acid and more than 35% saturated fatty acids. 

Milk lipids have attracted the interest of and have frustrated investigators. The lipids are readily available, for example in butter, but are exceptionally complex, both with respect to lipid classes and to component fatty acids. Furthermore, the latter have been difficult to analyze because of the shortchain fatty acids present and the large number of fatty acids in general. Jenness and Patton (1959) listed 16 fatty acids found in milk lipids. The list had grown to about 150 by 1967 (Jensen et al. 1967) and is now over 400 (Table 4.1). 

Table 4.3. Composition and Stereospecific Distribution of Fatty Acids in Milk Fat Trigylcerides from Bimonthly Samples of Maleny Butter.

Cho et al. (1977) has identified the fatty acids in the lysophosphati-dyl-ethanolamines and -cholines from butter serum. The compositions were similar to those of the intact phospholipids. 

Van der Wei, H. and De Jong, K. 1967. Occadecadienoic acids in butter fat. II. Identification of some nonconjugated fatty acids. Fette Seifen. Anstrichm. 64, 277-279. Weihrauch, J. L., Brewington, C. R. and Schwartz, D. P. 1974. Trace components in milk fat Isolation and identification of oxofatty acids. Lipids 9, 883-890. 

The study was conducted on a series of lipids such as oils, tallow and butter. Figures 7-4 and 7-5 illustrate Raman spectra of sunflower, corn, sesame, rapeseed and olive oils and peanut, beef tallow and butter, respectively. The study determined that the iodine number of the lipid containing foodstuffs could be estimated by measuring the FT-Raman spectra. The presence of double bonds in the unsaturated fatty acids in lipids provides a method of... 

Except for enzyme-directed processes to place certain fatty acids in specific positions on TAG, such as production of coating fats, cocoa butter substitutes, or reduced-calorie fats,135 the... 

The positional distribution of fatty acids in pig fat (lard) and cocoa butter is shown in Table 2-15. Most of the unsaturation in lard is located in the 1- and 3-positions, whereas in cocoa butter the major portion of the unsaturation is located in the 2-position. This... 

Table 2-15 Positional Distribution Fatty Acids in Pig Fat and Cocoa Butter...

Octadecanoic Stearic 69.6 Major fatty acid in animal tissues and some fungi, usually minor in plants, major only in a few plant species (e.g., cocoa butter). 

Considerable recent research has defined conditions for successful use of lipases and other enzymes in numerous lipid modification reactions, including a variety of types of interesterifications (69, 71, 76). For edible applications to date, they have been employed at industrial scales for the production of (1) cocoa butter substitutes, for which disaturated, monounsaturated acylglycerols with the unsaturated fatty acid in the sn-2 position are desired (77) (2) to produce human milkfat analogues, where 2-palmitoyl acylglycerols are desired (77) (3) in the synthesis of 1,3- di-acylglycerols (78) and in the production of diacylglycerols for edible applications. These reactions employ vegetable oils as feedstocks. 

Most of the flavor compounds in fats and oils are produced by the reaction of oxygen with unsaturated fatty acids in triacylglycerols or polar lipids. On the other hand, some flavor compounds such as those present in cocoa butter, roasted sesame oil, or roasted peanut oil are generated by the interaction of reducing sugars with amino compounds during thermal processing. 

Butter Because of their commercial significance, the flavor of butter and butter oil has been studied extensively. More than 230 volatile compounds have been identified in different types of butter as well as butter oil (20). The typical flavor of fresh butter is influenced by carbonyl compounds formed by oxidation of unsaturated fatty acids in milk. Critical flavors in butter have recently been reviewed (21, 22). 

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