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 connotating a process that makes a mixture the same throughout the entire substance.
Chemistry
Intensive mixing of mutually insoluble
phases (sometimes with addition of
Surfactants) to obtain a soluble
suspension or
emulsion.
In Science:
- Homogeneous — a mixture that is the same(uniform) throughout.
- Heterogeneous — a mixture that has separate 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
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
extruders,
hammermills and
colloid mills.
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).
Cell biology
Homogenization is a process that involves breaking apart cells - releasing organelles and
cytoplasm. When the purpose is to extract
organelles, it is frequently done in two steps; first using a
blender to break the tissue up, and then with an
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 acids, 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
osmotic damage.
See also
References
Conversi, Daniele 2007 'Homogenisation, nationalism and war: Should we still read Ernest Gellner?’,
Nations and Nationalism, Vol. 13, no 3, 2007, pp. 1–24
External links
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Agricultural science is a broad multidisciplinary field that encompasses the parts of exact, natural, economic and social sciences that are used in the practice and understanding of agriculture. (Veterinary science, but not animal science, is often excluded from the definition.
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Food technology, or Food tech for short is the application of food science to the selection, preservation, processing, packaging, distribution, and use of safe, nutritious, and wholesome food.
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Sociology (from Latin: socitus, "companion"; and the suffix -ology, "the study of", from Greek λόγος, lógos, "knowledge") is the systematic and scientific study of society and societal behavior.
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Cell biology (also called cellular biology or formerly cytology, from the Greek kytos, "container") is an academic discipline that studies cells. This includes their physiological properties, their structure, the organelles they contain, interactions with
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In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i.e. density, crystal structure, index of refraction, and so forth).
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Surfactants, also known as tensides, are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids.
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Suspension is a heterogenous fluid containing solid particles that are sufficiently large for sedimentation. Usually they must be larger than 1 micrometre [1]. Unlike colloids, suspensions will eventually settle. An example of a suspension would be sand in water.
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emulsion is a mixture of two immiscible (unblendable) substances. One substance (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include butter and margarine, espresso, mayonnaise, the photo-sensitive side of photographic film, and
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Milk is an opaque white liquid produced by the mammary glands of female mammals (including monotremes). Mammary glands are highly specialized sweat glands. The female ability to produce milk is one of the defining characteristics of mammals.
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Cream (from Greek chrisma) is a dairy product that is composed of the higher-butterfat layer skimmed from the top of milk before homogenization. In un-homogenized milk, over time, the lighter fat rises to the top.
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emulsion is a mixture of two immiscible (unblendable) substances. One substance (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include butter and margarine, espresso, mayonnaise, the photo-sensitive side of photographic film, and
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grinding mill is a unit operation designed to break a solid material into smaller pieces. There are many different types of grinding mills and many types of materials processed in them.
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Extrusion is a manufacturing process used to create long objects of a fixed cross-sectional profile. A material, often in the form of a billet, is pushed and/or drawn through a die of the desired profile shape.
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hammermill is a machine whose purpose is to shred material into fine particles. They have many sorts of applications in many industries, including:
- Ethanol plants (corn)
- Used Pallet Industry (grinding for mulch)
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Cytoplasm is a gelatinous, semi-transparent fluid that fills most cells. Eukaryotic cells contain a nucleus that is kept separate from the cytoplasm by a double membrane layer. The cytoplasm has three major elements; the cytosol, organelles and inclusions.
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In cell biology, an organelle is a specialized subunit within a cell, having a specific function, and separately enclosed within its own lipid membrane.
The name organelle
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A blender or liquidiser (UK) is a kitchen appliance used to mix ingredients or puree food. The term typically refers to a stationary, upright electrical device, which is to be distinguished from a hand-powered or electric mixer that may be used for similar purposes.
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Ultrasound is a cyclic sound pressure with a frequency greater than the upper limit of human hearing, this limit being approximately 20 kilohertz (20,000 hertz).
Ability to hear ultrasound
..... Click the link for more information. Differential centrifugation is a procedure in which a homogenate is subjected to repeated centrifugations each time increasing the centrifugal force. Separation is based predominantly on particle mass and size with larger and heavier particles pelleting at lower centrifugal fields.
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A nucleic acid is a macromolecule composed of nucleotide chains. In biochemistry these molecules carry genetic information or form structures within cells. The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
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mortar and pestle is a tool used to crush, grind, and mix substances. The pestle is a heavy stick whose end is used for pounding and grinding, and the mortar is a bowl. The substance is ground between the pestle and the mortar.
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Liquid nitrogen (liquid density at the triple point is 0.807 g/mL) is the liquid produced industrially in large quantities by fractional distillation of liquid air and is often referred to by the abbreviation, LN2. It is pure nitrogen, in a liquid state.
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Autolysis is a process by which a biological cell self-destructs. It is uncommon in adult organisms and usually occurs in injured cells or dying tissue. It occurs when a lysosome allows the digestive enzymes out of its membranes. The cell then, in effect, digests itself.
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Osmosis is the net movement of water across a partially permeable membrane from a region of high solvent potential to an area of low solvent potential, up a solute concentration gradient.
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Pasteurization (or pasteurisation) is the process of heating liquids for the purpose of destroying viruses and harmful organisms such as bacteria, protozoa, molds, and yeasts. The process was named after its inventor, French scientist Louis Pasteur.
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