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64-458: In curdling, the pH of the milk decreases and becomes more acidic. Independently floating casein molecules attract one another, forming "curdles" that float in a translucent whey . At warmer temperatures, the clumping reaction occurs more quickly than at colder temperature. Curdling occurs naturally if cows' milk is left open in a warm environment to air for a few days. Milk and soy milk are curdled intentionally to make cheese and tofu by

128-453: A casein-free diet has been shown to improve outcomes of infants who are breastfed while allergic or intolerant to dairy protein. Human breast milk has been proven to be the best food for an infant, and should be tried first where available. Supplementation of protease enzyme has been shown to help casein intolerant individuals digest the protein with minimal adverse reaction. Ions An ion ( / ˈ aɪ . ɒ n , - ən / )

192-444: A magnetic field . Electrons, due to their smaller mass and thus larger space-filling properties as matter waves , determine the size of atoms and molecules that possess any electrons at all. Thus, anions (negatively charged ions) are larger than the parent molecule or atom, as the excess electron(s) repel each other and add to the physical size of the ion, because its size is determined by its electron cloud . Cations are smaller than

256-523: A proteolytic enzyme known as rennin ; traditionally obtained from the stomachs of calves , but currently produced more often from genetically modified microorganisms. The solids are then separated and pressed into final form. Unlike many proteins, casein is not coagulated by heat. During the process of clotting, milk-clotting proteases act on the soluble portion of the caseins, κ-casein , thus originating an unstable micellar state that results in clot formation. When coagulated with chymosin , casein

320-427: A form of tempera paint, and was widely used by commercial illustrators as the material of choice until the late 1960s when, with the advent of acrylic paint , casein became less popular. It is still widely used by scenic painters, although acrylic has made inroads in that field as well. Casein-based glues are formulated from casein, water, and alkalis (usually a mix of hydrated lime and sodium hydroxide ). Milk

384-454: A free electron and a positive ion. Ions are also created by chemical interactions, such as the dissolution of a salt in liquids, or by other means, such as passing a direct current through a conducting solution, dissolving an anode via ionization . The word ion was coined from neuter present participle of Greek ἰέναι ( ienai ), meaning "to go". A cation is something that moves down ( Greek : κάτω , kato , meaning "down") and an anion

448-415: A gas is extensively used for the detection of radiation such as alpha , beta , gamma , and X-rays . The original ionization event in these instruments results in the formation of an "ion pair"; a positive ion and a free electron, by ion impact by the radiation on the gas molecules. The ionization chamber is the simplest of these detectors, and collects all the charges created by direct ionization within

512-400: A gas with less net electric charge is called the ionization potential , or ionization energy . The n th ionization energy of an atom is the energy required to detach its n th electron after the first n − 1 electrons have already been detached. Each successive ionization energy is markedly greater than the last. Particularly great increases occur after any given block of atomic orbitals

576-412: 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

640-483: A minus indication "Anion (−)" indicates the negative charge. With a cation it is just the opposite: it has fewer electrons than protons, giving it a net positive charge, hence the indication "Cation (+)". Since the electric charge on a proton is equal in magnitude to the charge on an electron, the net electric charge on an ion is equal to the number of protons in the ion minus the number of electrons. An anion (−) ( / ˈ æ n ˌ aɪ . ən / ANN -eye-ən , from

704-440: A molecule/atom with multiple charges is by drawing out the signs multiple times, this is often seen with transition metals. Chemists sometimes circle the sign; this is merely ornamental and does not alter the chemical meaning. All three representations of Fe , Fe , and Fe shown in the figure, are thus equivalent. Monatomic ions are sometimes also denoted with Roman numerals , particularly in spectroscopy ; for example,

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768-402: A neutral atom or molecule is called ionization . Atoms can be ionized by bombardment with radiation , but the more usual process of ionization encountered in chemistry is the transfer of electrons between atoms or molecules. This transfer is usually driven by the attaining of stable ("closed shell") electronic configurations . Atoms will gain or lose electrons depending on which action takes

832-592: A positive charge, forming the ion NH + 3 . However, this ion is unstable, because it has an incomplete valence shell around the nitrogen atom, making it a very reactive radical ion. Due to the instability of radical ions, polyatomic and molecular ions are usually formed by gaining or losing elemental ions such as H , rather than gaining or losing electrons. This allows the molecule to preserve its stable electronic configuration while acquiring an electrical charge. The energy required to detach an electron in its lowest energy state from an atom or molecule of

896-411: A precise ionic gradient across membranes , the disruption of this gradient contributes to cell death. This is a common mechanism exploited by natural and artificial biocides , including the ion channels gramicidin and amphotericin (a fungicide ). Inorganic dissolved ions are a component of total dissolved solids , a widely known indicator of water quality . The ionizing effect of radiation on

960-401: A product in the early 1920s named Casec to ease gastrointestinal disorders and infant digestive problems which were a common cause of death in children at that time. All caseinates have very efficient emulsifying properties and widely used to make emulsions in foods. It is believed to neutralize capsaicin , the active ingredient of chili peppers such as jalapeños , and habaneros . Milk

1024-453: A ratio of fat to egg may also cause curdling. In sauces which include milk or yogurt , overheating often causes curdling. The higher the fat content, the less likely curdling is. Strained yogurt used in sauces also curdles only with difficulty. When a plant based milk such as soya milk is added to coffee, curdling can sometimes occur. To help prevent this manufacturers sometimes add acidity regulators. When making cheesecake , if water

1088-408: A result, it has relatively little tertiary structure . It is relatively hydrophobic , making it poorly soluble in water . It is found in milk as a suspension of particles, called casein micelles , which show only limited resemblance with surfactant -type micelles in a sense that the hydrophilic parts reside at the surface and they are spherical. However, in sharp contrast to surfactant micelles,

1152-414: A stable configuration. This property is known as electropositivity . Non-metals, on the other hand, are characterized by having an electron configuration just a few electrons short of a stable configuration. As such, they have the tendency to gain more electrons in order to achieve a stable configuration. This tendency is known as electronegativity . When a highly electropositive metal is combined with

1216-701: A use in certain niche applications, such as laminating fireproof doors and the labeling of bottles. Casein glues thin rapidly with increasing temperature, making it easy to apply thin films quickly to label jars and bottles on a production line. Several foods, creams, and toppings all contain a variety of caseinates. Sodium caseinate acts as a greater food additive for stabilizing processed foods; however, companies could opt to use calcium caseinate to increase calcium content and decrease sodium levels in their products. The main food uses of casein are for powders requiring rapid dispersion into water, ranging from coffee creamers to instant cream soups. Mead Johnson introduced

1280-401: A −2 charge is known as a dianion and an ion with a +2 charge is known as a dication . A zwitterion is a neutral molecule with positive and negative charges at different locations within that molecule. Cations and anions are measured by their ionic radius and they differ in relative size: "Cations are small, most of them less than 10 m (10 cm) in radius. But most anions are large, as is

1344-507: Is skimmed to remove the fat, then the milk is soured so that the casein is precipitated as milk curd . The curd is washed (removing the whey ), and then the curd is pressed to squeeze out the water (it may even be dried to a powder). The casein is mixed with alkali (usually both sodium and calcium hydroxide) to make glue. Glues made with different mixes of alkalis have different properties. Preservatives may also be added. They were popular for woodworking, including for aircraft, as late as

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1408-564: Is a salt of calcium . An attractive property of the casein molecule is its ability to form a gel or clot in the stomach, which makes it very efficient in nutrient supply. The clot is able to provide a sustained slow release of amino acids into the blood stream, sometimes lasting for several hours. Often casein is available as hydrolyzed casein , whereby it is hydrolyzed by a protease such as trypsin . Hydrolyzed forms are noted to taste bitter and such supplements are often refused by infants and lab animals in favor of intact casein. Some of

1472-416: Is a negatively charged ion with more electrons than protons. (e.g. Cl (chloride ion) and OH (hydroxide ion)). Opposite electric charges are pulled towards one another by electrostatic force , so cations and anions attract each other and readily form ionic compounds . If only a + or - is present, it indicates a +1 or -1 charge. To indicate a more severe charge, the number of additional or missing atoms

1536-469: 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 phosphorus . Casein contains a high number of proline amino acids which hinder the formation of common secondary structural motifs of proteins. There are also no disulfide bridges . As

1600-476: Is added to the cream cheese during the combining period, it will curdle. Casein Casein ( / ˈ k eɪ s iː n / KAY -seen , from Latin caseus "cheese") is a family of related phosphoproteins ( αS1 , aS2, β , 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 human milk . Sheep and cow milk have

1664-484: Is an atom or molecule with a net electrical charge . The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton , which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons (e.g. K (potassium ion)) while an anion

1728-448: Is commonly practiced by these individuals after discovering their intolerance or allergy. Casein that is heat-treated has been shown to be more allergenic and harder to digest when fed to infants. Breast milk has not typically been shown to cause an allergic reaction, but should be administered to an infant with caution each time in case of adverse reaction from something the breastfeeding parent consumed that contained casein. Following

1792-429: Is exhausted of electrons. For this reason, ions tend to form in ways that leave them with full orbital blocks. For example, sodium has one valence electron in its outermost shell, so in ionized form it is commonly found with one lost electron, as Na . On the other side of the periodic table, chlorine has seven valence electrons, so in ionized form it is commonly found with one gained electron, as Cl . Caesium has

1856-615: Is in the breakdown of adenosine triphosphate ( ATP ), which provides the energy for many reactions in biological systems. Ions can be non-chemically prepared using various ion sources , usually involving high voltage or temperature. These are used in a multitude of devices such as mass spectrometers , optical emission spectrometers , particle accelerators , ion implanters , and ion engines . As reactive charged particles, they are also used in air purification by disrupting microbes, and in household items such as smoke detectors . As signalling and metabolism in organisms are controlled by

1920-524: Is not enough good evidence that caseins in milk increase the risk of getting cancer . A1 and A2 beta-casein are genetic variants of the beta-casein milk protein that differ by one amino acid ; a proline occurs at position 67 in the chain of amino acids that make up the A2 beta-casein, while in A1 beta-casein a histidine occurs at that position. Due to the way that beta-casein interacts with enzymes found in

1984-432: Is often consumed to decrease irritation caused by spicy foods. Cheese consists of proteins and fat from milk , usually the milk of cows , buffalo , goats , or sheep . It is produced by coagulation that is caused by destabilization of the casein micelle, which begins the processes of fractionation and selective concentration. Typically, the milk is acidified and then coagulated by the addition of rennet , containing

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2048-607: Is one short of the stable, filled shell with 8 electrons. Thus, a chlorine atom tends to gain an extra electron and attain a stable 8- electron configuration , becoming a chloride anion in the process: This driving force is what causes sodium and chlorine to undergo a chemical reaction, wherein the "extra" electron is transferred from sodium to chlorine, forming sodium cations and chloride anions. Being oppositely charged, these cations and anions form ionic bonds and combine to form sodium chloride , NaCl, more commonly known as table salt. Polyatomic and molecular ions are often formed by

2112-451: Is possible to mix the notations for the individual metal centre with a polyatomic complex, as shown by the uranyl ion example. If an ion contains unpaired electrons , it is called a radical ion. Just like uncharged radicals, radical ions are very reactive. Polyatomic ions containing oxygen, such as carbonate and sulfate, are called oxyanions . Molecular ions that contain at least one carbon to hydrogen bond are called organic ions . If

2176-473: Is something that moves up ( Greek : ἄνω , ano , meaning "up"). They are so called because ions move toward the electrode of opposite charge. This term was introduced (after a suggestion by the English polymath William Whewell ) by English physicist and chemist Michael Faraday in 1834 for the then-unknown species that goes from one electrode to the other through an aqueous medium. Faraday did not know

2240-486: Is sometimes called paracasein . Chymosin (EC 3.4.23.4) is an aspartic protease that specifically hydrolyzes the peptide bond in Phe105-Met106 of κ-casein, and is considered to be the most efficient protease for the cheese-making industry (Rao et al., 1998). British terminology, on the other hand, uses the term caseinogen for the uncoagulated protein and casein for the coagulated protein . As it exists in milk, it

2304-415: Is supplied, as seen in O 2 (negative charge, peroxide ) and He (positive charge, alpha particle ). Ions consisting of only a single atom are termed atomic or monatomic ions , while two or more atoms form molecular ions or polyatomic ions . In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of

2368-457: Is water-insoluble. While it is also insoluble in neutral salt solutions, it is readily dispersible in dilute alkalis and in salt solutions such as aqueous sodium oxalate and sodium acetate . The enzyme trypsin can hydrolyze a phosphate -containing peptone . It is used to form a type of organic adhesive . Casein paint is a fast-drying, water-soluble medium used by artists. Casein paint has been used since ancient Egyptian times as

2432-432: Is written in superscript immediately after the chemical structure for the molecule/atom. The net charge is written with the magnitude before the sign; that is, a doubly charged cation is indicated as 2+ instead of +2 . However, the magnitude of the charge is omitted for singly charged molecules/atoms; for example, the sodium cation is indicated as Na and not Na . An alternative (and acceptable) way of showing

2496-556: The Fe (positively doubly charged) example seen above is referred to as Fe(III) , Fe or Fe III (Fe I for a neutral Fe atom, Fe II for a singly ionized Fe ion). The Roman numeral designates the formal oxidation state of an element, whereas the superscripted Indo-Arabic numerals denote the net charge. The two notations are, therefore, exchangeable for monatomic ions, but the Roman numerals cannot be applied to polyatomic ions. However, it

2560-572: The de Havilland Albatross airliner in 1939. Casein glue is also used in transformer manufacturing (specifically transformer board) due to its oil permeability. Elmer's Glue-All, Elmer's School Glue and many other Borden adhesives were originally made from casein. While one reason was its non-toxic nature, a primary factor was that it was economical to use. Towards the end of the 20th century, Borden replaced casein in all of its popular adhesives with synthetics like PVA . While largely replaced with synthetic resins, casein-based glues still have

2624-560: The ACP onto tooth surfaces, where it can facilitate remineralization. Casein and gluten exclusion diets are sometimes used in alternative medicine for children with autism . As of 2015 the evidence that such diets have any impact on behavior or cognitive and social functioning in autistic children was limited and weak. Casein proteins have potential for use as nanomaterials due to their readily available source (milk) and their propensity to self-assemble into amyloid fibrils. There

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2688-541: The Greek word ἄνω ( ánō ), meaning "up" ) is an ion with more electrons than protons, giving it a net negative charge (since electrons are negatively charged and protons are positively charged). A cation (+) ( / ˈ k æ t ˌ aɪ . ən / KAT -eye-ən , from the Greek word κάτω ( kátō ), meaning "down" ) is an ion with fewer electrons than protons, giving it a positive charge. There are additional names used for ions with multiple charges. For example, an ion with

2752-467: The addition of enzymes (typically rennet ), acids (including lemon juice ), or various salts ( magnesium chloride , calcium chloride , or gypsum ); the resulting curds are then pressed. In hot preparations emulsified with eggs like hollandaise and custard , curdling is the undesirable result of overheating the sauce. Sauces which contain starch curdle with more difficulty. In cold sauces like mayonnaise as well as in hot sauces, too large

2816-494: The body cannot break down the proteins of casein. The prevalence of casein allergy or intolerance ranges from 0.25 to 4.9% of young children. Numbers for older children and adults are not known. A significant portion of those on the autism spectrum have an intolerance or allergy to casein protein into adulthood. This can be used by clinicians and dietitians to spot autism in those who may not present with traditional autistic traits . A diet known as casein-free, gluten free (CFGF)

2880-519: The charge in an organic ion is formally centred on a carbon, it is termed a carbocation (if positively charged) or carbanion (if negatively charged). Monatomic ions are formed by the gain or loss of electrons to the valence shell (the outer-most electron shell) in an atom. The inner shells of an atom are filled with electrons that are tightly bound to the positively charged atomic nucleus , and so do not participate in this kind of chemical interaction. The process of gaining or losing electrons from

2944-409: The corresponding parent atom or molecule due to the smaller size of the electron cloud. One particular cation (that of hydrogen) contains no electrons, and thus consists of a single proton – much smaller than the parent hydrogen atom. Anion (−) and cation (+) indicate the net electric charge on an ion. An ion that has more electrons than protons, giving it a net negative charge, is named an anion, and

3008-565: The digestive system, A1 and A2 are processed differently by digestive enzymes , and a seven-amino peptide , beta- casomorphin -7, (BCM-7) can be released by digestion of A1-beta-casein. The A1 beta-casein type is the most common type found in cow's milk in Europe (excluding Italy and France which have more A2 cows), the United States, Australia, and New Zealand. Interest in the distinction between A1 and A2 beta-casein proteins began in

3072-532: The earliest plastics were based on casein. In particular, galalith was well known for use in buttons . Fiber can be made from extruded casein. Lanital , a fabric made from casein fiber (known as Aralac in the United States), was particularly popular in Italy during the 1930s. Casein-derived compounds are used in tooth remineralization products to stabilize amorphous calcium phosphate (ACP) and release

3136-459: The early 1990s through epidemiological research and animal studies initially conducted by scientists in New Zealand, which found correlations between the prevalence of milk with A1 beta-casein proteins and various chronic diseases. The research generated interest in the media, among some in the scientific community, and entrepreneurs. A company, A2 Corporation, was founded in New Zealand in

3200-579: The early 2000s to commercialize the test and market "A2 Milk" as premium milk that is healthier due to the lack of peptides from A1. A2 Milk even petitioned the Food Standards Australia New Zealand regulatory authority to require a health warning on ordinary milk. Responding to public interest, the marketing of A2 milk, and the scientific evidence that had been published, an independent review published in 2005 found no discernible difference between drinking A1 or A2 milk on

3264-454: The gaining or losing of elemental ions such as a proton, H , in neutral molecules. For example, when ammonia , NH 3 , accepts a proton, H —a process called protonation —it forms the ammonium ion, NH + 4 . Ammonia and ammonium have the same number of electrons in essentially the same electronic configuration , but ammonium has an extra proton that gives it a net positive charge. Ammonia can also lose an electron to gain

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3328-435: The gas through the application of an electric field. The Geiger–Müller tube and the proportional counter both use a phenomenon known as a Townsend avalanche to multiply the effect of the original ionizing event by means of a cascade effect whereby the free electrons are given sufficient energy by the electric field to release further electrons by ion impact. When writing the chemical formula for an ion, its net charge

3392-411: The interior of a casein micelle is highly hydrated. The caseins in the micelles are held together by calcium ions and hydrophobic interactions. Any of several molecular models could account for the special conformation of casein in the micelles. One of them proposes the micellar nucleus is formed by several submicelles, the periphery consisting of microvillosities of κ-casein. Another model suggests

3456-417: The least energy. For example, a sodium atom, Na, has a single electron in its valence shell, surrounding 2 stable, filled inner shells of 2 and 8 electrons. Since these filled shells are very stable, a sodium atom tends to lose its extra electron and attain this stable configuration, becoming a sodium cation in the process On the other hand, a chlorine atom, Cl, has 7 electrons in its valence shell, which

3520-641: The liquid or solid state when salts interact with solvents (for example, water) to produce solvated ions , which are more stable, for reasons involving a combination of energy and entropy changes as the ions move away from each other to interact with the liquid. These stabilized species are more commonly found in the environment at low temperatures. A common example is the ions present in seawater, which are derived from dissolved salts. As charged objects, ions are attracted to opposite electric charges (positive to negative, and vice versa) and repelled by like charges. When they move, their trajectories can be deflected by

3584-409: The lowest measured ionization energy of all the elements and helium has the greatest. In general, the ionization energy of metals is much lower than the ionization energy of nonmetals , which is why, in general, metals will lose electrons to form positively charged ions and nonmetals will gain electrons to form negatively charged ions. Ionic bonding is a kind of chemical bonding that arises from

3648-510: The luminescence of the Sun to the existence of the Earth's ionosphere . Atoms in their ionic state may have a different color from neutral atoms, and thus light absorption by metal ions gives the color of gemstones . In both inorganic and organic chemistry (including biochemistry), the interaction of water and ions is often relevant for understanding properties of systems; an example of their importance

3712-479: The most common Earth anion, oxygen . From this fact it is apparent that most of the space of a crystal is occupied by the anion and that the cations fit into the spaces between them." The terms anion and cation (for ions that respectively travel to the anode and cathode during electrolysis) were introduced by Michael Faraday in 1834 following his consultation with William Whewell . Ions are ubiquitous in nature and are responsible for diverse phenomena from

3776-454: The mutual attraction of oppositely charged ions. Ions of like charge repel each other, and ions of opposite charge attract each other. Therefore, ions do not usually exist on their own, but will bind with ions of opposite charge to form a crystal lattice . The resulting compound is called an ionic compound , and is said to be held together by ionic bonding . In ionic compounds there arise characteristic distances between ion neighbours from which

3840-451: The nature of these species, but he knew that since metals dissolved into and entered a solution at one electrode and new metal came forth from a solution at the other electrode; that some kind of substance has moved through the solution in a current. This conveys matter from one place to the other. In correspondence with Faraday, Whewell also coined the words anode and cathode , as well as anion and cation as ions that are attracted to

3904-411: The nucleus is formed by casein-interlinked fibrils. Finally, the most recent model proposes a double link among the caseins for gelling to take place. All three models consider micelles as colloidal particles formed by casein aggregates wrapped up in soluble κ-casein molecules. The isoelectric point of casein is 4.6. Since milk's pH is 6.6, casein has a negative charge in milk. The purified protein

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3968-664: The respective electrodes. Svante Arrhenius put forth, in his 1884 dissertation, the explanation of the fact that solid crystalline salts dissociate into paired charged particles when dissolved, for which he would win the 1903 Nobel Prize in Chemistry. Arrhenius' explanation was that in forming a solution, the salt dissociates into Faraday's ions, he proposed that ions formed even in the absence of an electric current. Ions in their gas-like state are highly reactive and will rapidly interact with ions of opposite charge to give neutral molecules or ionic salts. Ions are also produced in

4032-399: The risk of contracting chronic diseases. The European Food Safety Authority (EFSA) reviewed the scientific literature and published a review in 2009 found no identifiable relationship between chronic diseases and drinking milk with the A1 protein. A small fraction of the population is allergic to casein. Casein intolerance , also known as "milk protein intolerance", is experienced when

4096-434: The spatial extension and the ionic radius of individual ions may be derived. The most common type of ionic bonding is seen in compounds of metals and nonmetals (except noble gases , which rarely form chemical compounds). Metals are characterized by having a small number of electrons in excess of a stable, closed-shell electronic configuration . As such, they have the tendency to lose these extra electrons in order to attain

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