Homogenization 209207 215797489 2008-05-29T19:27:26Z ClueBot 4928500 Reverting possible vandalism by [[Special:Contributions/204.83.37.243|204.83.37.243]] to version by 74.5.73.39. False positive? [[User:ClueBot/FalsePositives|Report it]]. Thanks, [[User:ClueBot]]. (400327) (Bot) '''Homogenization''' (or '''homogenisation''') is a term used in many fields such as [[chemistry]], [[agricultural science]], [[food technology]], [[sociology]] and [[cell biology]]. Homogenization is a term connoting a process that makes a mixture the same throughout the entire substance. ==Chemistry== Intensive mixing of mutually insoluble [[phase (matter)|phases]] (sometimes with addition of [[surfactant]]s) to obtain a soluble [[suspension (chemistry)|suspension]] or [[emulsion]]. In science: *Homogeneous — a mixture that is the same(uniform) throughout. *Heterogeneous — a mixture consisting of dissimilar elements or parts. ==Food technology== One of the oldest applications of homogenization is in [[milk]] processing, where the aim is to prevent or delay the natural separation of [[cream]] from the rest of the [[emulsion]]. The fat in milk normally separates from the water and collects at the top. Homogenization is the process of breaking up that fat into smaller sizes so that it no longer separates from the milk, allowing the sale of non-separating 2% and whole milk. This is accomplished by forcing the milk at high pressure through small orifices. When soft solids are [[mill (grinding)|milled]] in a liquid, this can also be seen as a form of homogenization. Among the many types of equipment that can be used for this process are [[extruder]]s, [[hammermill]]s and [[colloid mill]]s. == Sociology and history == In sociology and history, the term ''homogenization'' has largely negative meanings, indicating a drive towards uniformity, militarism, obedience and conformism. This is often superimposed forcibly by the state, but can also be the result of global economic forces (Conversi 2007). The term ''homogenization'' has a close relationship to [[Americanization]]. ==Cell biology== Homogenization is a process that involves breaking apart cells — releasing organelles and [[cytoplasm]]. When the purpose is to extract [[organelle]]s, it is frequently done in two steps; first using a [[blender (device)|blender]] to break the [[Biological_tissue|tissue]] up, and then with an [[ultrasound|ultrasonic]] or mechanical tissue disruptor. The organelles are then generally separated using [[differential centrifugation]]. Depending upon the subcellular fraction wanted, different processes are used to separate them. When the aim is to extract [[nucleic acid]]s, the tissue is often ground in a [[mortar and pestle]] under [[liquid nitrogen]]. Sometimes, however, a much milder procedure is followed, where the aim is to collect whole, intact cells. Homogenized cells must be kept at low temperatures to prevent [[autolysis]] and kept in an [[isotonic solution]] to prevent [[osmosis|osmotic]] damage. ==See also== *[[Pasteurization]] ==References== Conversi, Daniele 2007 'Homogenisation, nationalism and war: Should we still read Ernest Gellner?’, [http://www.blackwell-synergy.com/doi/abs/10.1111/j.1469-8129.2007.00292.x Nations and Nationalism], Vol. 13, no 3, 2007, pp. 1–24 ==External links== * [http://www.niro-soavi.com/SOAVI/CMSDoc.nsf/WebDoc/ndkw73egqz Homogenization Concept] The Dynamic High Pressure * [http://www.niroinc.com/html/soavi/stechnolgy.html homogenization equipment] with detailed description * [http://www.foodsci.uoguelph.ca/dairyedu/homogenization.html explanation of the technology] along with theories on how the homogenization mechanism actually works. * [http://www.proscientific.com/Homogenizing.shtml Homogenizing with Blades, Rotors and Pressure homogenizers.] *[http://www.howstuffworks.com/question147.htm How Stuff Works - Homogenization and Pasteurization] * [http://www.omni-inc.com/images/ALN_Jahn_Reprint.pdf High Throughput Homogenization] * [http://www.omni-inc.com/index.php?main_page=page_4 Eliminating Cross Contamination During Homogenization] [[Category:Unit operations]] [[Category:Food science]] [[Category:Cell biology]] [[Category:Laboratory techniques]] [[da:Homogenisering]] [[de:Homogenisierung]] [[es:Homogeneización]] [[nl:Homogeniseren]] [[no:Homogenisering]] [[nn:Homogenisering]] [[pl:Homogenizacja]] [[ru:Гомогенизация]] [[sv:Homogenisering]] [[ur:ہمجنسگری]]