Calcium removal from milk

The use of different sorbents for the removal of mycotoxins has been the subject of intense studies. Aflatoxins may be removed from milk, cream or peanut oil using hydrated calcium aluminosilicate clay or bentonite. These mineral materials are sometimes added directly to feed to immobilise mycotoxins in the digestive tract of livestock (reducing the transfer into the blood stream). For example, the addition of hydrated calcium aluminosilicate to the feed of dairy cows decreases excretion of aflatoxin Mj to milk by 24-44%. Experiments with the immobilisation of zearalenone have been promising. However, the question remains as to whether the use of these chemisorbents does not reduce the intake of some essential minerals (such as copper, zinc and iron) and water-soluble vitamins. 

Evaporated milk is a Hquid product obtained by the partial removal of water only from milk. It has a minimum milk-fat content of 7.5 mol % and a minimum milk-solids content of 25.0 mol %. Evaporated skimmed milk is a Hquid product obtained by the partial removal of water only from skimmed milk. It has a minimum milk-solids content of 20.0 mol %. Sweetened condensed milk is a product obtained by the partial removal of water only from milk with the addition of sugars. It has a minimum milk-fat content of 8.0 mol % and a minimum milk-solids content of 28.0 mol %. Skimmed sweetened condensed milk is a product obtained by the partial removal of water only from skimmed milk with the addition of sugars. It has a minimum milk-solids content of 24.0 mol %. AH may contain food additives (qv) as stabilizers, in maximum amounts, including sodium, potassium, and calcium salts of hydrochloric acid at 2000 mg/kg singly citric acid, carbonic acid, orthophosphoric acid, and polyphosphoric acid at 3000 mg/kg in combination, expressed as anhydrous substances and in the evaporated milk carrageenin may be added at 150 mg/kg. 

Milk from cows contains 3.2% protein, about 80% of which is casein. Casein is isolated by a precipitation process from milk, involving heating, rinsing to remove whey, and drying to a powder. The yield is about 3 kg/ 100 kg skim milk. Rennet casein is obtained when the casein is precipitated by chymosin enzyme, also known as rennet, and acid casein is produced when precipitation is accomplished by acidification. Acid casein is usually found in the form of sodium caseinate or calcium caseinate, which are water-soluble salts. Caseinates are made by reacting NaOH or CaOH with a slurry of casein curd or powder and then spray drying (Southward, 2010). 

P. Romer mixed a hot cone. soln. of equi-molecular parts of potassium sulphate and dichromate with enough milk of lime to precipitate the combined sulphuric acid as calcium sulphate. The precipitate was removed from the soln. of potassium chromate i The soln, was... 

Use Ceramics, calcium acid phosphate, phosphorus and phosphoric acid, polishing powder, cattle foods, clarifying sugar syrups, medicine, mordant (dyeing textiles with Turkey red), fertilizers, dentifrices, stabilizer for plastics, in meat tenderizers, in foods as anticaking agent, buffer, nutrient supplement, removal of Sr from milk. 

Cows milk is more salty than milk from human mothers, and this limits its use in the preparation of infant formula. Desalting of cows milk by ED allows larger quantities of cows milk solids to be used for these purposes. Research has shown that desalting by ED to remove calcium improved the protein stability of frozen skim milk and its concentrates.7 The lumpy texture of thawed frozen milk has been attributed to clumping of micellar casein, and calcium removal led to the dissociation of micellar to serum casein. 

Magnesium ions are removed from the crude brine as a precipitate of magnesium hydroxide by adding milk of lime (or caustic soda). Calcium ions are removed by the addition of either sodium carbonate solution, or by injecting carbon dioxide in the form of combustion gases. 

This carbon dioxide-free solution is usually treated in an external, weU-agitated liming tank called a "prelimer." Then the ammonium chloride reacts with milk of lime and the resultant ammonia gas is vented back to the distiller. Hot calcium chloride solution, containing residual ammonia in the form of ammonium hydroxide, flows back to a lower section of the distiller. Low pressure steam sweeps practically all of the ammonia out of the limed solution. The final solution, known as "distiller waste," contains calcium chloride, unreacted sodium chloride, and excess lime. It is diluted by the condensed steam and the water in which the lime was conveyed to the reaction. Distiller waste also contains inert soHds brought in with the lime. In some plants, calcium chloride [10045-52-4], CaCl, is recovered from part of this solution. Close control of the distillation process is requited in order to thoroughly strip carbon dioxide, avoid waste of lime, and achieve nearly complete ammonia recovery. The hot (56°C) mixture of wet ammonia and carbon dioxide leaving the top of the distiller is cooled to remove water vapor before being sent back to the ammonia absorber. 

Both lime and slaked limes are use to reduce sulfur emissions, which contribute to acid precipitation, from power plants, particularly coal-fired plants. By using lime, more than 95% of the sulfur can be eliminated from the emissions. Calcium oxide reacts with sulfur dioxide to produce calcium sulfite CaOfe) + S02( —> CaS03(). Sulfur dioxide is also removed by spraying limewater in the flue gas. Limewater, also called milk of lime, is a fine suspension of calcium hydroxide in water. Other pollutants removed with lime include sulfur trioxide, hydrofluoric acid, and hydrochloric acid. 

Removal of colloidal calcium phosphate (CCP) results in disintegration of the micelles into particles of mass 3 x 106 Da. The properties of the CCP-free system are very different from those of the normal milk system, e.g. it is sensitive to and precipitated by relatively low concentrations of Ca2 +, it is more stable to high temperatures, e.g. 140°C, and is not coagulable by rennets. Many of these properties can be restored, at least partially, by increased concentrations of calcium. 

Brines are also cone, by evaporation under reduced press., i.e. in what are called vacuum fans heated by steam, and specially designed to eliminate difficulties arising from the tendency of the brine to deposit a hard scale or crust of calcium salts. In some cases, the magnesium salts are first precipitated as magnesium hydroxide, Mg(OH)2, by the addition of milk of lime, and the calcium sulphate subsequently removed by precipitation as carbonate by the addition of ammonium carbonate liquors. The decanted liquor is then cone, in vacuum pans. 

Fractionation of milk and titration of the fractions have been of considerable value. Rice and Markley (1924) made an attempt to assign contributions of the various milk components to titratable acidity. One scheme utilizes oxalate to precipitate calcium and rennet to remove the calcium caseinate phosphate micelles (Horst 1947 Ling 1936 Pyne and Ryan 1950). As formulated by Ling, the scheme involves titrations of milk, oxalated milk, rennet whey, and oxalated rennet whey to the phenolphthalein endpoint. From such titrations, Ling calculated that the caseinate contributed about 0.8 mEq of the total titer of 2.2 mEq/100 ml (0.19% lactic acid) in certain milks that he analyzed. These data are consistent with calculations based on the concentrations of phosphate and proteins present (Walstra and Jenness 1984). The casein, serum proteins, colloidal inorganic phosphorus, and dissolved inorganic phosphorus were accounted for by van der Have et al (1979) in their equation relating the titratable acidity of individual cow s milks to the composition. The casein and phosphates account for the major part of the titratable acidity of fresh milk. 

Lowering the pH of milk to 4.6 solubilizes colloidal calcium phosphate. This removes its neutralizing effect, allowing electrostatic interactions between micelles. Under these conditions, micelles coagulate and precipitate from solution. Kudo (1980C) showed that release of whey proteins and K-casein from casein micelle surfaces as the pH is increased from 6.2 to 7.2 allows micelles to stick together and precipitate from solution. 

Whatever the true nature of idiopathic hypercalcemia, most are agreed that there is evidence of increased vitamin D-like activity. We know too that the administration of vitamin D in this condition may sometimes further raise the serum calcium level B5, C3, F7). The removal of all added vitamin D from the diet is therefore logical and in practice appears beneficial. So many proprietary milks and prepared foods are fortified with vitamin D that it is necessary to be vigilant in selecting a dietary. 

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