Milk fat

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Milk fat is the entirety of the lipid components of milk . Fat is the ingredient with the most fluctuating content in milk. It is between 3.2 and 6.0%. In addition to the breed of cattle , the feeding , keeping and health of the dairy animals are primarily responsible for these fluctuations . This also results in the different fat composition.

The fat is contained in milk in the form of tiny globules or droplets ( emulsion ). The actual milk fat is surrounded by a thin layer of lipids (e.g. cholesterol and phospholipids ). These lipids have lipophilic and hydrophilic molecular parts that can interact with fats (lipophilic parts) or with water and other polar molecules (hydrophilic parts). As a result, the lipids act as emulsifiers and stabilize the small fat droplets in the otherwise watery milk.

In untreated raw milk , the majority of these fat globules have a diameter of around 1 to 5 µm. Untreated milk creams up, ie the lipid phase separates and settles on the surface after a shorter standing time. To counteract this effect, commercially available fresh milk is homogenized (in addition to heat treatment to increase its shelf life) . The lipid globules are "broken down" to a diameter of less than 1 µm.

Milk fat carrier of fat soluble vitamins A , D , E and K .

Chemical composition

Typical triglyceride in milk fat with the blue marked saturated fatty acid residue of palmitic acid, the green marked monounsaturated fatty acid residue of oleic acid and the red marked residue of butyric acid. The triple acylated glycerine ( marked black ) can be seen in the center.

Milk fat is mainly composed of triglycerides , the esters of the trihydric alcohol glycerine with fatty acids. Milk fat has a relatively high content of esterified short fatty acids (such as butyric acid ) and a relatively low content of polyunsaturated fatty acids (linoleic acid, linolenic acid, etc.).

Only the fatty acids with four to 16 carbon atoms are synthesized by the cow, fatty acids with 16 to 18 carbon atoms come from the feed.

Fatty acid residues in the triglycerides
of milk fat
fatty acid Number of carbon atoms:
double bonds 		Salary [%]
Butyric acid 4-0 3.3-4.6
Caproic acid 6-0 2.9-3.0
Caprylic acid 8-0 1.0-1.7
Capric acid 10-0 1.9-4.1
Lauric acid 12: 0 2.3-6.4
Myristic acid 14: 0 8.6-14.6
Myristoleic acid 14: 1 1.1-1.5
Palmitic acid 16: 0 22.2-36.7
Palmitoleic acid 16: 1 1.8-2.3
Stearic acid 18: 0 6.1-12.7
Oleic acid 18: 1 17.2-29.7
Linoleic acid 18: 2 1.0-3.1
Linolenic acid 18: 3 0.7-3.0

As a mixture of liquid and crystallized triacylglycerides, milk fat is liquid at room temperature. Milk is an emulsion of liquid milk fat in water, butter is a "solid emulsion" of water in semi-liquid milk fat, in clarified butter milk fat is pure and completely crystallized. Milk fat and clarified butter are therefore solid at room temperature.

Food law

For the EU internal market , marketing standards determine the requirements for agricultural products intended for human consumption that remain spreadable at 20 degrees Celsius with a mass fraction of 10% to less than 90% milk fats, fats or mixed vegetable and / or animal fats, i.e. spreadable fats . Milk fats are defined as a type of fat , namely as fats in the form of a solid, plastic emulsion, predominantly of the water in oil type, which consist exclusively of milk and / or certain milk products with fat as an essential component of their value. Other substances necessary for their production may also be added to them, provided these substances are not intended to replace a milk component in whole or in part.

The milk fat percentage then determines the food , under the name of butter placed on the market may be: butter must have a fat content of at least 80% and less than 90%, a maximum water content of 16% and a maximum content of non-fat milk solids of 2% have. Spreadable fats with a certain lower milk fat content can be described as three-quarter butter , semi-fat butter or milk fat X% .

literature

  • Donald L. Palmquist: Milk Fat. Origin of Fatty Acids and Influence of Nutritional Factors Thereon. In: Patrick F. Fox, Paul LH McSweeney (Eds.): Advanced Dairy Chemistry. Volume 2: Lipids. 3. Edition. Springer, New York NY 2006, ISBN 0-387-26364-0 , pp. 43-92.

Individual evidence

  1. ^ Hans-Dieter Belitz , Werner Grosch, Peter Schieberle : Textbook of Food Chemistry 6th, completely revised edition. Springer, Berlin et al. 2008, ISBN 978-3-540-73201-3 , p. 530.
  2. ↑ Hans-Jochen Fiebig: Fatty acid composition of important vegetable and animal edible fats and oils , Münster, December 21, 2011.
  3. ^ Alfred Töpel: Chemistry and Physics of Milk. Behr, Hamburg 2004, ISBN 3-89947-131-8 , p. 153, available in excerpts from Google Books.
  4. ↑ Art. 115 Regulation (EC) No. 1234/2007 of the Council of October 22, 2007 on a common organization of agricultural markets and with special provisions for certain agricultural products ( Regulation on the single CMO) with Annex XV.
  5. ↑ Group A of the Annex to Annex XV to Regulation (EC) No. 1234/2007
  6. ↑ Part A No. 1 of the annex to Annex XV to EC (Regulation) No. 1234/2007.