Goats’ milk fat

Massart-Leen et al. (1981) analyzed bovine milk fat and goat milk fat for branched chain fatty acids. They did not find the same diversity of fatty acids in bovine as in goat milk fat and as previously reported. The authors suggested that the difference—the absence of branched chain acids other than iso and anteiso in bovine milk fat—could be caused by the relative inefficiency of the incorporations of methylmalonic acid into the biosynthetic pathway. 

Caponio, F., Allogio, V. and Pallavicini, C. (1998) Modification of goat milk fat triglycerides by immobilised lipase. Fett Lipid, 100, 74-78. 

Ruiz-Sala, P., Hierro, M.T.G., Martinez-Castro, I., Santa-Maria, G. 1996. Triglyceride composition of ewe, cow and goat milk fat. J. Amer. Oil Chem. Soc., 73, 283-293. 

Lee, J.H., Melton, S.L., Waller, J.C., and Saxton, A.M. (2004). Modification of physicochemical characteristics of goat milk fat by feeding protected high oleic sunflower oil supplements. ]. Food Sci. 69, C280-C286. 

Tsiplakou, E., Mountzouris, K.C., and Zervas, G. (2006). Concentration of conjugated linoleic acid in grazing sheep and goat milk fat. Livestock Sci. 103,74-84. 

Calsamiglia S, Busquet M, Cardozo PW, CastUlejos L, Ferret A (2007) Essential oils as modifiers of mmen microbial fermentation. J Dairy Sci 90 2580-2595 Chifliard Y, Glasser F, Ferlay A, Bernard L, Rouel J, Doreau M (2007) Diet, rumen biohydrogenation and nutritional quality of cow and goat milk fat. Eur J Lipid Sd Technol 109 828-855... 

Average recoveries for fenoxycarb, Ro-16-8797, and Ro-17-3192 for all animal sample substrates ranged from 80% (beef kidney) to 111% (goat kidney), 76% (goat milk) to 93% (beef omental fat), and 56% (dairy milk) to 76% (beef perirenal fat), respectively. The LOQ and LOD were 0.01 ig g and 2.5 ng injected, respectively. 

Vitamin A activity is present in milk as retinol, retinyl esters and as carotenes. Whole cows milk contains an average of 52 fig retinol and 21 fig carotene per 100 g. The concentration of retinol in raw sheep s and pasteurized goats milks is 83 and 44 fig per 100 g, respectively, although milks of these species are reported (Holland et ai, 1991) to contain only trace amounts of carotenes. Human milk and colostrum contain an average of 58 and 155 fig retinol per lOOg, respectively. In addition to their role as provitamin A, the carotenoids in milk are reponsible for the colour of milk fat (Chapter 11). 

Grappin, R. and Jeunet, R. 1979. Routine methods for measuring fat and protein in goats milk. Lait 59, 345-360. 

Puri, B. R., Parkash, S. and Chandan, R. C. 1961. Studies in physico-chemical properties of milk. Part IX. Variation in fat globule size-distribution curves of cow and buffalo milk, on the removed of fat and addition of goat milk. Ind. J. Dairy Sci. 14, 31-35. 

Precht et al. (2001) found that the proportion of trans-18 1 fatty acid isomers was similar in the milk fat of the cow, goat and sheep vaccenic acid (llr-18 l) was the major isomer in all these milks, accounting for 51, 37 and 47% of the total, respectively. The isomers between 91 and 161, excluding the 111, made up most of the rest (4-10% each). 

Triacylglycerols are synthesised in the mammary gland, and the enzyme specificity and substrate availability play a role in the final structure of the molecule. Table 1.18 shows the fatty acids esterified at each position of the triacylglycerols in the milk of various species. The distinctive feature of the triacylglycerols of ruminants (cow, sheep and goat) is the presence of the short-chain fatty acids, 4 0 and 6 0, which are esterified almost exclusively at the sn-3 position. In human and porcine milk fat more than 50% of the 16 0 is at the sn-2 position however, in the milk fat of cow, sheep and goat, 16 0 is distributed more evenly between the sn-1 and sn-2 positions. 18 1 is esterified preferentially at the sn-1 and sn-3 positions in human, porcine and bovine milk fat, although for the cow, the total amount of 18 1 is less. In ovine and caprine milk fat, 18 1 is favoured at the sn-3 position and there are smaller but similar amounts at the other two positions. 

Precht, D., Molkentin, J., Wolff, R.L. 2001. Comparative studies on individual isomeric 18 1 acids in cow, goat, and ewe milk fats. Lipids, 36, 827-832. 

Modern concepts of milk fat synthesis developed rapidly in the 1950s with the carefully-designed physiological studies in lactating goats by Popjak et al. (1951) which showed unequivocally the de novo synthesis of short-chain fatty acids from 14C-labelled acetate. Also, the incorporation of tritium-labelled stearic acid into milk fat was demonstrated by Glascock et al. (1956). From empirical calculations of the quantity of dietary fat and the recovery of label in milk fat, the latter authors estimated that dietary fat contributed a maximum 25% of the weight of milk fat. 

Annison, E.F., Linzell, J.L., Fazakerley, S., Nichols, B.W. 1967. The oxidation and utilization of palmitate, stearate, oleate and acetate by the mammary gland of the fed goat in relation to their overall metabolism, and the role of plasma phospholipids and neutral lipids in milk-fat synthesis. Biochem. J. 102, 637-647. 

Popjak, G., French, T.H., Folley, S.J. 1951. Utilization of acetate for milk-fat synthesis in the lactating goat. Biochem. J. 48, 411-416. 

West, C.E., Bickerstaffe, R., Annison, E.F., Linzell, J.L. 1972. Studies on the mode of uptake of blood triglycerides by the mammary gland of the lactating goat. The uptake and incorporation into milk fat and mammary lymph of labeled glycerol, fatty acids and triglycerides. Biochem. J. 126, 477-490. 

Fahmi, A.H., Sirry, I., Safwat, A. 1956. The size of fat globules and the creaming power of cow, buffalo, sheep and goat milk. Indian J. Dairy Sci. 9, 124-130. 

Jenness, R., Parkash, S. 1971. Lack of a fat globule clustering agent in goats milk. J. Dairy Sci. 54, 123-126. 

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