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Syneresis (chemistry)
Syneresis (also spelled 'synæresis' or 'synaeresis'), in chemistry, is the solvent extraction, extraction or expulsion of a liquid from a gel, such as when Serum (blood), serum drains from a contracting clot of blood. Another example of syneresis is the collection of whey on the surface of yogurt. Syneresis can also be observed when the amount of diluent in a swollen polymer exceeds the solubility limit as the temperature changes. A household example of this is the counterintuitive expulsion of water from dry gelatin when the temperature increases. Syneresis has also been proposed as the mechanism of formation for the Silicon dioxide, amorphous silica composing the frustule of diatoms. Examples In the processing of dairy milk, for example during cheese making, syneresis is the formation of the curd due to the sudden removal of the hydrophilic peptides, macropeptides, which causes an imbalance in intermolecular forces. Bonds between hydrophobic sites start to develop and are enfor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvent Extraction
A solvent (from the Latin language, Latin ''wikt:solvo#Latin, solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a Solution (chemistry), solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for Chemical polarity#Polarity of molecules, polar molecules, and the most common solvent used by living things; all the ions and proteins in a Cell (biology), cell are dissolved in water within the cell. Major uses of solvents are in paints, paint removers, inks, and dry cleaning. Specific uses for Organic compound, organic solvents are in dry cleaning (e.g. tetrachloroethylene); as paint thinners (toluene, turpentine); as nail polish removers and solvents of glue (acetone, methyl acetate, ethyl acetate); in spot removers (hexane, petrol ether); in detergents (D-limonene, citrus terpenes); and in perfumes (ethanol). Solvents find various applications in chemical, pharmaceutical, oil, and gas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptides
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Dalton (unit), Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. Peptides fall under the broad chemical classes of biopolymer, biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligand (biochemistry), ligands such as coenzymes and cofactor (biochemistry), cofactors, to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed Residue (chemistry)#Biochemistry, residues. A water molecule is released during formation of each amide bond.. Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Processes
A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combined without reacting, they may form a chemical mixture. If a mixture is separated to isolate one chemical substance to a desired degree, the resulting substance is said to be chemically pure. Chemical substances can exist in several different physical states or phases (e.g. solids, liquids, gases, or plasma) without changing their chemical composition. Substances transition between these phases of matter in response to changes in temperature or pressure. Some chemical substances can be combined or converted into new substances by means of chemical reactions. Chemicals that do not possess this ability are said to be inert. Pure water is an example of a chemical substance, with a constant composition of two hydrogen atoms bonded to a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flocculation
In colloidal chemistry, flocculation is a process by which colloidal particles come out of Suspension (chemistry), suspension to sediment in the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from Precipitation (chemistry), precipitation in that, prior to flocculation, colloids are merely suspended, under the form of a stable dispersion (where the internal phase (solid) is dispersed throughout the external phase (fluid) through mechanical agitation) and are not truly dissolved in Solution (chemistry), solution. Coagulation (water treatment), Coagulation and flocculation are important processes in fermentation and water treatment with coagulation aimed to destabilize and aggregate particles through chemical interactions between the coagulant and colloids, and flocculation to sediment the destabilized particles by causing their aggregation into floc. Term definition According to the IUPAC definition, flocculation is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coagulation
Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a thrombus, blood clot. It results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The process of coagulation involves Platelet-activating factor, activation, Cell adhesion, adhesion and aggregation of platelets, as well as deposition and maturation of fibrin. Coagulation begins almost instantly after an injury to the endothelium that lines a blood vessel. Exposure of blood to the subendothelial space initiates two processes: changes in platelets, and the exposure of subendothelial Tissue factor, platelet tissue factor to coagulation factor VII, which ultimately leads to cross-linked fibrin formation. Platelets immediately form a plug at the site of injury; this is called ''primary hemostasis. Secondary hemostasis'' occurs simultaneously: additional coagulation factors beyond factor VII (#Coagulation factors, listed below) respond in a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imbibition
Imbibition is a special type of diffusion that takes place when liquid is absorbed by solids-Colloid, colloids causing an increase in volume. Water surface potential movement takes place along a concentration gradient; some dry materials absorb water. A gradient between the absorbent and the liquid is essential for imbibition. For a substance to imbibe a liquid, there must first be some attraction between them. Imbibition occurs when a wetting fluid displaces a non-wetting fluid, the opposite of drainage in which a non-wetting phase displaces the wetting fluid. The two processes are governed by different mechanisms. Imbibition is also a type of diffusion since water movement is along the concentration gradient. Seeds and other such materials have almost no water hence they absorb water easily. Water potential gradient between the absorbent and liquid imbibed is essential for imbibition. Examples One example of Imbibition in nature is the absorption (chemistry), absorption of w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alginate
Alginic acid, also called algin, is a naturally occurring, edible polysaccharide found in brown algae. It is hydrophilic and forms a viscous gum when hydrated. When the alginic acid binds with sodium and calcium ions, the resulting salts are known as alginates. Its colour ranges from white to yellowish-brown. It is sold in filamentous, granular, or powdered forms. It is a significant component of the biofilms produced by the bacterium '' Pseudomonas aeruginosa'', a major pathogen found in the lungs of some people who have cystic fibrosis. The biofilm and ''P. aeruginosa'' have a high resistance to antibiotics, but are susceptible to inhibition by macrophages. Alginate was discovered by British chemical scientist E. C. C. Stanford in 1881, and he patented an extraction process for it in the same year. The alginate was extracted, in the original patent, by first soaking the algae in water or diluted acid, then extracting the alginate by soaking it in sodium carbonate, and fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agarose
Agarose is a heteropolysaccharide, generally extracted from certain red algae. It is a linear polymer made up of the repeating unit of agarobiose, which is a disaccharide made up of D-galactose and 3,6-anhydro-L-galactopyranose. Agarose is one of the two principal components of agar, and is purified from agar by removing agar's other component, agaropectin. Agarose is frequently used in molecular biology for the separation of large molecules, especially DNA, by electrophoresis. Slabs of agarose gels (usually 0.7 - 2%) for electrophoresis are readily prepared by pouring the warm, liquid solution into a mold. A wide range of different agaroses of varying molecular weights and properties are commercially available for this purpose. Agarose may also be formed into beads and used in a number of chromatographic methods for protein purification. Structure Agarose is a linear polymer with a molecular weight of about 120,000, consisting of alternating D- galactose and 3,6-an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crème Brûlée
''Crème brûlée'' (; ), also known as burnt cream, Cambridge burnt cream, or Trinity cream, and virtually identical to '' crema catalana'', is a dessert consisting of a rich custard base topped with a layer of hardened caramelized sugar. It is normally served slightly chilled; the heat from the caramelizing process tends to warm the top of the custard, while leaving the center cool. The custard base is generally flavored with vanilla in French cuisine, but can have other flavorings. It is sometimes garnished with fruit. History The earliest known recipe of a dessert called ''crème brûlée'' appears in François Massialot's 1691 cookbook , but its ultimate origins are unclear. The recipe is based on egg yolks and milk, with a pinch of flour. Once cooked, François Massialot specifies "that it must be sweetened on top, in addition to the sugar that is put in it: we take the shovel from the fire, very red at the same time we burn the cream, so that it takes a beautiful colo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Custard
Custard is a variety of culinary preparations based on sweetened milk, cheese, or cream cooked with Eggs as food, egg or egg yolk to thicken it, and sometimes also flour, corn starch, or gelatin. Depending on the recipe, custard may vary in consistency from a thin pouring sauce () to the thick pastry cream () used to fill éclairs. The most common custards are used in List of custard desserts, custard desserts or dessert sauces and typically include sugar and vanilla; however, Umami, savory custards are also found, e.g., in quiche. Preparation Custard is usually cooked in a double boiler (''bain-marie''), or heated very gently in a saucepan on a stove, though custard can also be steamed, baked in the oven with or without a Bain-marie, water bath, or even cooked in a Pressure cooking, pressure cooker. Custard preparation is a delicate operation because a ''temperature'' increase of leads to overcooking and curdling. Generally, a fully cooked custard should not exceed ; it begins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rennet
Rennet () is a complex set of enzymes produced in the stomachs of ruminant mammals. Chymosin, its key component, is a protease, protease enzyme that curdling, curdles the casein in milk. In addition to chymosin, rennet contains other enzymes, such as pepsin and a lipase. Rennet has traditionally been used to separate milk into solid curds and liquid whey, used in the production of cheeses. Rennet from calves has become less common for this use, to the point that less than 5% of cheese in the United States is made using animal rennet today. Most cheese is now made using chymosin derived from bacterial sources. Molecular action of rennet enzymes One of the main actions of rennet is its protease chymosin cleaving the kappa casein chain. Casein is the main protein of Milk#Proteins, milk. Cleavage removes the slightly negatively charged glycomacropeptide (GMP) from the surface of the casein micelle. Because negative charges repel other negative charges, the GMP prevents casein micell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casein
Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins (CSN1S1, αS1, aS2, CSN2, β, K-casein, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of the proteins in breast milk, human milk. Sheep's milk, Sheep and cow milk have a higher casein content than other types of milk with human milk having a particularly low casein content. Casein is the primary emulsifier in milk, that is, it helps in mixing oils, fats, and water in milk. Casein has a wide variety of uses, from being a major component of cheese, to use as a food additive. The most common form of casein is sodium caseinate (historically called nutrose), which is a very efficient emulsifier. Casein is secreted into milk from mammary cells in the form of colloidal casein micelles, a type of biomolecular condensate. As a food source, casein supplies amino acids, carbohydrates, and two essential elements, calcium and phosphoru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
