{{Short description|Chemical process}} thumb|400px|Homogenizing valve, a method to homogenize at high pressure<ref>{{Cite web |date=September 2019 |title=The Effect of the Second-Stage Homogenizing Valve |url=https://www.spxflow.com/assets/pdf/apv-homogenizer-second-stage-homogenizing-valve-tb58-apv-3077-dst-gb.pdf |access-date=2024-02-01 |publisher=SPXFLOW |type=Technical bulletin}}</ref> '''Homogenization''' or '''homogenisation''' is any of several processes used to make a mixture of two mutually non-soluble liquids the same throughout.<ref>{{Cite web |last=Brakeman |first=Rob |title=Homogenizing Process {{!}} Homogenization {{!}} Sonic Mixing Corp |url=https://www.sonicmixing.com/homogenization-process/ |access-date=2024-02-01 |website=Sonic Corporation |language=en-US}}</ref> This is achieved by turning one of the liquids into a state consisting of extremely small particles distributed uniformly throughout the other liquid. A typical example is the homogenization of milk, wherein the milk fat globules are reduced in size and dispersed<ref name=":0">{{Cite web |date=2021-08-06 |title=Why Is Milk Homogenized and What Are its Effects? {{!}} Dairy Nutrition |url=https://dairynutrition.ca/en/milk-quality/homogenization/why-milk-homogenized-and-what-are-its-effects |access-date=2024-02-01 |website=dairynutrition.ca |language=en}}</ref> uniformly through the rest of the milk.<ref name=Britannica_online>{{Citation | contribution = Homogenization | title = Encyclopædia Britannica. Encyclopædia Britannica Online Academic Edition | publisher = Encyclopædia Britannica Inc. | access-date = October 6, 2013 | contribution-url = http://www.britannica.com/EBchecked/topic/270516/homogenization }}</ref>
==Definition== Homogenization (from ''homogeneous''; Greek, {{Lang|grc-latn|homogenes}}: {{Lang|grc-latn|homos}}'','' {{Gloss|same}} + {{Lang|grc-latn|genos}}'','' {{Gloss|kind}})<ref>[http://dictionary.reference.com/browse/homo- homo-, word origin]</ref> is the process of converting two immiscible liquids (i.e. liquids that are not soluble, in all proportions, one in another) into an emulsion,<ref name=Food_Lipids>{{cite book | last =McClements | first = David J. | chapter = Lipid-Based Emulsions and Emulsifiers |editor1-last=Akoh |editor1-first=Casimir C. |editor2-last=Min |editor2-first=David B. | title=Food Lipids: Chemistry, Nutrition, and Biotechnology |chapter-url=https://books.google.com/books?id=sPglndmgXU8C&q=Casimir+and+Akoh+V.+Emulsion+Formation&pg=PA77 |edition=Third |series=Food Science and Technology |year=2008 |publisher=CRC |location=Boca Raton, Florida |isbn=978-1420046649 |page= 77 }}</ref> a mixture of two or more liquids that are generally immiscible. Sometimes two types of homogenization are distinguished: primary homogenization, when the emulsion is created directly from separate liquids; and secondary homogenization, when the emulsion is created by the reduction in size of droplets in an existing emulsion.<ref name=Food_Lipids/> Homogenization is achieved by a mechanical device called a ''homogenizer''.<ref name=Food_Lipids/>
==Application== One of the oldest applications of homogenization is in milk processing.<ref name=":1">{{Cite web |last= |date=2022-09-03 |title=Homogenization of Milk: What It Is and How to Process |url=https://ginhong.com/homogenization-of-milk-what-it-is-and-how-to-process/ |access-date=2024-02-01 |website=Ginhong |language=en-US}}</ref> It is normally preceded by standardization (the mixing of milk from several different herds or dairies to produce a more consistent raw milk prior to processing).<ref name=":1" /> The fat in milk normally separates from the water and collects at the top. Homogenization breaks the fat into smaller sizes so it no longer separates, allowing the sale of non-separating milk at any fat specification.<ref name=":0" />
==Methods==
===High-pressure homogenization===
In high-pressure homogenization, a liquid product is forced through a narrow orifice under pressures typically ranging from 1,500 to 35,000 psi. This process reduces particle and droplet size through a combination of shear, turbulence, and cavitation. It is commonly used in the dairy industry to homogenize milk, producing uniform fat distribution and improving product stability.<ref name=":1" />
High-pressure homogenization is also applied in other beverage categories, such as soft drinks and vegetable-based drinks, to prevent the separation of components during storage. Ultra-high-pressure homogenization (UHPH) systems have been developed to further enhance microbiological stability and shelf life.<ref>{{cite journal |last1=Ferragut |first1=Victoria |last2=Hernández-Herrero |first2=Manuela |last3=Veciana-Nogués |first3=María Teresa |last4=Borras-Suarez |first4=Miquel |last5=González-Linares |first5=Javier |last6=Vidal-Carou |first6=María Carmen |last7=Guamis |first7=Buenaventura |title=Ultra-high-pressure homogenization (UHPH) system for producing high-quality vegetable-based beverages: physicochemical, microbiological, nutritional and toxicological characteristics: Soy and almond beverages produced by UHPH |journal=Journal of the Science of Food and Agriculture |date=30 March 2015 |volume=95 |issue=5 |pages=953–961 |doi=10.1002/jsfa.6769 |pmid=24898984 }}</ref><ref>{{Cite web |last1=Müller |first1=U. |last2=Rossmann |first2=S. |last3=Schneider |first3=J. |last4=Kohlus |first4=R. |title=(231aj) Direct Homogenization of Beverage Emulsions with the Innovative Counterflow Injection Process {{!}} AIChE |url=https://www.aiche.org/conferences/aiche-annual-meeting/2016/proceeding/paper/231aj-direct-homogenization-beverage-emulsions-innovative-counterflow-injection-process |access-date=2024-02-01 |website=www.aiche.org}}</ref>
===High-shear homogenization===
High-shear homogenization uses a rotor/stator mechanism to apply intense mechanical shear to a product, promoting dispersion and droplet size reduction. This method is widely used in industries such as food, pharmaceuticals, and cosmetics. Rotor/stator mixers typically achieve droplet sizes in the range of 2–5 microns, with finer distributions possible depending on formulation and processing conditions.<ref>{{cite web|url=https://www.silverson.com/us/products/homogenizers/|title=Benchtop to Inline Homogenizer Mixers - High Shear Homogenizers|publisher=Silverson Machines|access-date=2025-05-07}}</ref>
A key advantage of high-shear homogenization is that it can improve emulsion uniformity and stability without altering formulation components. This is especially important for commercial products with fixed or regulated ingredient profiles. In a 2016 study, applying high-shear homogenization at 3600 rpm significantly reduced droplet size, improved viscosity, and eliminated phase separation in oil-in-water emulsions, all while maintaining the original formula.<ref>{{cite web |last1=Silva |first1=T. M. |last2=Cerize |first2=N. N. P. |last3=Oliveira |first3=A. M. |title=The Effect of High Shear Homogenization on Physical Stability of Emulsions |url=https://www.researchgate.net/publication/368181316_The_Effect_of_High_Shear_Homogenization_on_Physical_Stability_of_Emulsions |website=ResearchGate |publisher=Institute for Technological Research |access-date=2025-05-07}}</ref>
==See also== * Ultrasonic homogenizer * French pressure cell press * Homogenizer * Cell disruption
==References== {{Reflist}}
Category:Unit operations Category:Food processing Category:Laboratory techniques