Dairy fats fatty acid source

Butyric acid is a carboxylic acid also classified as a fatty acid. It exists in two isomeric forms as shown previously, but this entry focuses on n-butyric acid or butanoic acid. It is a colorless, viscous, rancid-smelling liquid that is present as esters in animal fats and plant oils. Butyric acid exists as a glyceride in butter, with a concentration of about 4% dairy and egg products are a primary source of butyric acid. When butter or other food products go rancid, free butyric acid is liberated by hydrolysis, producing the rancid smell. It also occurs in animal fat and plant oils. Butyric acid gets its name from the Latin butyrum, or butter. It was discovered by Adolf Lieben (1836—1914) and Antonio Rossi in 1869. 

Morales, M.S., Palmquist, D.L., Weiss, W.P. 2000. Effects of fat source and copper on unsaturation of blood and milk triacylglycerol fatty acids in Holstein and Jersey cows. J. Dairy Sci. 83, 2105-2111. 

The predominant source of CLA in human diets is ruminant-derived food products. CLA is a fatty acid so it is present in milk fat and muscle fat. In the U.S., dairy products provide about 70% of the intake of CLA and beef products account for another 25% (Ritzenthaler et al., 2001). Similar values for the contribution of different food classes have been reported for other countries (see Parodi, 2003). 

Although significant strides have been directed at reducing fat content in food products, certain lipid ingredients and sources of fatty acids are used to enhance the health and nutritional quality of foods. For example, CLA isomers were enriched in both dairy and nondairy products to convey its anticancer and antiobesity effects that were reported repeatedly in animal studies (39). Sources of n-3 PUFAs are also added directly to infant formula to provide sufficient DHA for normal development of the nervous system during early infancy. In the United States, DHA was approved by the FDA in 2001 to be added into infant formula (40, 41). 

Cholesterol is presented to the intestinal wall from three sources the diet, bile and intestinal secretions, and cells. Animal products—especially meat, egg yolk, seafood, and whole-fat dairy products— provide the bulk of dietary cholesterol. Although cholesterol intake varies considerably according to the dietary intake of animal products, the average American diet is estimated to contain approximately 300 to 450 mg of cholesterol per day. A similar amount of cholesterol is present in the gut from biliary secretion and the turnover of mucosal cells. Practically ail cholesterol in the intestine is present in the unesterified (free) form. Esterified cholesterol in the diet is rapidly hydrolyzed in the intestine to free cholesterol and free fatty acids by cholesterol esterases secreted from the pancreas and small intestine. 

Kalscheur, K.F., Teter, B.B., Piperova, L.S., and Erdman, R.A. 1997a. Effect of fat source on duodenal flow of trans-Ci i fatty acids and milk fat production in dairy cows. J. Dairy Sci. 80, 2115-2126. 

In Refsum s disease, an autosomal recessive disorder, the defect is probably in the a-hydroxylation of phytanic acid. Phytanic acid is a 20-carbon, branched-chain fatty acid derived from the plant alcohol phytol, which is present as an ester in chlorophyll. Thus, its origin in the body is from dietary sources. The oxidation of phytanic acid is shown in Figure 18-6. The clinical characteristics of Refsum s disease include peripheral neuropathy and ataxia, retinitis pigmentosa, and abnormalities of skin and bones. Significant improvement has been observed when patients are kept on low-phytanic acid diets for prolonged periods (e.g., diets that exclude dairy and ruminant fat). 

Alkaline diets also have some limited positive aspects as well. Increasing the amount of plant-derived foods in the diet at the expense of meat, refined grains and sugar is usually a healthy idea. However, taken to the extremes, these principles may cause serious shortages of nutrients necessary for health. Avoiding fats and oils may be a source of illness becanse of a lack of essential fatty acids, whereas cutting out dairy products would lead to problems in maintaining an adequate supply of calciiun, vitamin D and proteins. 

Previously, low fat intakes were traditionally reeommended in the prevention of cardiovascular disease (CVD) as a component of a health promoting diet, without much attention to the quality of fat. However, current dietary guidelines generally put more emphasis on the quality of fat [1-4]. Imbalances in the amounts of individual fatty acids in the diet may have an impact on the occurrence of dyslipidemia, atherosclerosis, thrombosis, hypertension and obesity. Saturated fatty acids (SFA) have shown to be particularly important for development of the above mentioned diseases. However, in spite of an increasing body of new data, the role of individual dietary SFA in metabolic diseases is not fully clarified (Micha 2010). The reaches dietary sources of SFA include fast foods, processed foods, high-fat dairy products, red meats, and pork [1,5]. 

Agricultural enrichment of Q.A content in various animal species has received considerable attention. Lactating cows and beef cattle are the primary food sources of dietary CLA for human consumption. Among the factors that contribute to elevated CLA levels in these food products are ration modification, species of cow, and geographical and seasonal factors. Perhaps the most promising method of enrichment resides in the dietary supplementation of PUFA-rich materials, such as oil seeds and fish oil/meals, to the rations for dairy cows and beef cattle. Because these dietary supplements are also high in n-3 PUFA, additional benefits could be achieved by elevating n-3 fatty acids in both dairy and beef fats (39). 

Lipases. The major application of lipases in the dairy industry is in the production of Italian cheeses, for example, Romano and Provo-lone. These cheese varieties have a characteristic piquant flavour due to short-chain fatty acids liberated from the milk fat by lipases. The lipases used are mainly from oral tissues because these have a higher specificity than those from microbial sources. A considerable amount of information (Shahani, 1975) has been accumulated on the characteristics of lipolytic systems. 

The main forms of vitamin A include retinol esterified with higher fatty acids and free retinol or retinal. Precursors, or provitamins A, occur in food of animal origin in relatively small quantities. The most common ester of retinol is pahnitate, and esters with other fatty acids are also found in variable amounts. For example, the main component in milk is pahnitate followed by oleate and stearate. Other fatty acid esters (caprylate, caproate, Hnoleate, laurate, arachidonate, Hnolenate, myristate, pahnitoleate, pentadecanoate, gadoleate and heptadecanoate) and free retinol are also present in smaller amounts. One particularly rich source of vitamin A is Hver. For example, the retinol content in pork Hver is about 30 mg/kg, and the Hver of polar bears contains up to 60 g/kg of retinol. There is here a clear correlation with their diet, which consists mainly of seals. Milk (as weU as meat) contains relatively Httle vitamin A (the vitamin content is proportional to the fat content). Dairy products and butter are good sources of vitamin A because of their high fat content. 

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