Lipolysis, butter

Lipolysis Cundida hpobytica C rugosa, Torn lops is sphaerica Mainly in butter, margarine, and cheese. 

The difficulty in relating rancid flavors in butter to FFA content arises because the short-chain acids, C4 o and C6 o, which are the most flavorsome (McDaniel et al., 1969), are water-soluble and hence are mostly lost in the buttermilk and wash water during the manufacture of butter. For this reason, even butter made from cream with an ADV as high as 2.4 meq/lOOg fat may show little defect while on the other hand, butter with quite a low ADV can be rancid, particularly if lipolysis occurs after manufacture (Deeth et al., 1979 Woo and Lindsay, 1980). 

The flavor thresholds for the individual fatty acids are quite different in butter and in milk. Whereas in milk, Cio o and Ci2 o acids are most significant to rancid flavor, in butter C4 o and C o are of most interest since they have much lower flavor thresholds in fat than do the longer-chain acids (Patton, 1964). The reported thresholds of the C4 o to Ci2 o acids added singly or in pairs to butter are shown in Table 15.3, together with the theoretical amounts for an increase in ADV of 0.1 meq/100 g fat. From these data, it is evident that a low level of lipolysis in butter produces sufficient butyric acid to exceed its flavor threshold and to impart a rancid flavor. Thus, measurement of C o, C(, o and Cg o gives the best indication of hydrolytic rancidity in butter (McNeill et al., 1986). 

Deeth, H.C., Fitz-Gerald, C.H., Wood, A.F. 1979. Lipolysis and butter quality. Aust. J. Dairy Technol. 34, 146-149. 

O Connell, J.M., Cogan, T.M., Downey, W.K. 1975. Lipolysis in butter pre- and postmanufacture. Document 86, International Dairy Federation, Brussels, pp. 92-100. 

An increasing problem is lipolysis in butter fat after manufacturing, which is caused by thermoresistant hpase enzymes that are created in the milk or cream by psycho-trophic bacteria or by residual native lipases that sirrvive pasteurization. Based on a determination of the lipase activity in cream, the keeping quality of manufactured butter in regard to hpolysis can be predicted with reasonable accirracy. A similar prediction for sweet cream butter can be based on lipase activity in the serum phase (71). The characteristic lipolytic flavors that can develop in milk products are primarily associated with the short- and medium-chain fatty acids that are relatively abundant in milkfat they have lower flavor threshold values than the long-chain fatty acids. As a result of improvements in the quality of raw milk and the standards of processing, lipolytic rancidity is seldom present in the fat source before its use in recombination (72). 

With the solid test meal, the overall level of lipolysis was highly and significantly reduced by the double action of orlistat on the gastric and duodenal lipolysis (28.8% of controls for Xenical pellets, p<0.005 33.4% of controls for micronized orlistat powder in butter, p<0.001 Tab. 10.6). The difference between the two treated groups was not significant. 

The proposed EEC definition of a CBE (cocoa butter equivalent) fat includes a limit on the percentage of SOS-type triacylglycerols in the fat. To determine the percentage of SOS, a lipolysis method as described in Section 6.2.17 followed by 1,3-random, 2-random calculation would be unsuitable except for whole natural fats. 

Edwards-Webb, J.D. (1983) Digestive lipolysis in the preruminant calf. The abomasal hydrolysis of butter oil, coconut oil, palm oil and tallow. J. Sci. Food Agric. 34, 930-936. 

It is important to remember that ordinarily the major component of dietary fat is always triglyceride, not cholesterol. For example, milk and butter have very little cholesterol but are very high in triglyceride. Triglyceride (and other glycerolipids, such as phospholipids) are hydrolyzed in the intestinal lumen to yield monoglycerides and free fatty acids. These lipolysis products are then absorbed by the intestinal epithelial cells and resynthesized as triglycerides, phospholipids, and cholesterol esters. Thus, the intestine mediates both lipolysis (in the lumen) and re-esterification (within the epithelial cells) of dietary lipids. 

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