Protein concentrate, definition

Synonyms Lactis proteinum Protein, whey Whey protein concentrate Definition Polypeptide obtained from the fluid part of milk after separation from curds Uses Cosmetic protein protein source in animal feeds source of lactose and lactic acid synthesis of riboflavin, acetone, butanol, fuel-grade ethanol cheesemaking culture medium in rigid polyurethane foams moisture retention aid, emulsifier, stabilizer, opacifier, protein fortifier, fat replacer in foods Regulatory FDA 21CFR 135.110, 135.140, 184.1979c... 

The quantitation of a protein that has a specific biological function, a hormone, for instance, may not give a true indication of its biological activity owing to the inactivation of some of the protein. For proteins that have definite biological functions the choice is between chemical quantitation and bioassays. For this reason the catalytic activity of an enzyme is more frequently measured than is its protein concentration. 

Another useful quantitative definition of enzyme efficiency is specific activity. The specific activity of an enzyme is the number of enzyme units or katals per milligram of protein. This is a measure of the purity of an enzyme. If a solution contains 20 mg of protein that express 2 units of activity (33 nkatals), the specific activity of the enzyme is 2 units/20 mg = 0.1 units/mg or 33 nkatals/20 mg = 1.65 nkatals/mg. As an enzyme is purified, its specific activity increases. That is, during purification, the enzyme concentration increases relative to the total protein concentration until a limit is reached. The maximum specific activity is attained when the enzyme is homogeneous or in a pure form. 

Fig. 9a. Top Protein — soluble ligand classical binding equilibria and definition of 0 as moles bound ligand/moles total protein b. Center Protein adsorption — binding equilibria now treated in terms of soluble protein concentration ) now defined as moles bound protein/moles total immobilized ligand, c. Bottom Hill plots for each case, demonstrating that positive cooperativity with respect to binding of ligand is negative cooperativity with respect to binding (adsorption) of protein...

The first soybean protein ingredients made commercially available for food use included full-fat and defatted soy flours and grits (3, 7, 8). These products contain ca. 46-59% protein (NX 6.25) on a moisture-free basis and are available with various heat treatments for specific end-use. Soy protein concentrates and soy protein isolates were introduced into the market about 15 years ago (3, 9, 10, II). By definition soy protein concentrates must contain no less than 70% protein (N X 6.25) and isolates no less than 90% protein (N X 6.25), all on a moisure-free basis. In the past several years there has been much activity in the commercialization of textured soy protein products intended for the extension and replacement of meat. These textured products may be obtained through fiber spinning, shred formation, extrusion, or compaction (12, 13, 14, 15). In addition, soybean milk solids and the heterogeneous proteins in soybean whey might serve as useful substrates in chemical modifications for food use. This short recitation of commercial products illustrates the type of crude protein fractions available for practical modification. Many useful functional properties have been ascribed to these new food proteins. 

The order of both lysozymes affinity toward the three model surfaces was found to be DDS > silica > APS. The human lysozyme exhibited well defined plateaus on all three surfaces at relatively low protein concentrations (< 10 mg/ml), while for the hen lysozyme a definite plateau could only be seen on the DDS surface. Moreover, the amount of human lysozyme adsorbed per surface area appeared to be roughly three times that of the hen lysozyme on equivalent surfaces at low protein concentrations (< 5 mg/ml). Again, these results may not be accurate due to the limitations of the TIRIF quantitation scheme. 

As indicated in Table XIII, human exposure to soybean isoflavones, measured in DES equivalents, is considerably more likely than exposure to coumestrol in soybeans. Several fold Increases in Isoflavone content during germination is a definite possibility. The Importance of soybean estrogens, particularly in germinated soybeans, in the etiology of deleterious reactions in humans needs more study. Soybean isoflavones and phenolic acids probably account for the antioxidant activity of soybeans, defatted soy flour, protein concentrates, and Isolates (89). 

Water soluble protein with a relative molecular mass of ca. 32600, which particularly contains copper and zinc bound like chelate (ca. 4 gram atoms) and has superoxide-dismutase-activity. It is isolated from bovine liver or from hemolyzed, plasma free erythrocytes obtained from bovine blood. Purification by manyfold fractionated precipitation and solvolyse methods and definitive separation of the residual foreign proteins by denaturizing heating of the orgotein concentrate in buffer solution to ca. 65-70 C and gel filtration and/or dialysis. 

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