Water protein materials

On the plantations, the Hevea trees are tapped , i.e., the bark is cut and the latex which flows is collected in small cups. The latex is a stable dispersion of rubber in water, proteinous material being the dispersing agent a typical analysis might be as follows ... 

Finally, collagen can form a variety of collagen composites with other water-soluble materials. Ions, peptides, proteins, and polysaccharides can all be uniformly incorporated into a collagen matrix. The methods of composite formation include ionic and covalent bonding, entrapment, entanglement, and co-precipitation. A two-phase composite can be formed between collagen, ceramics, and synthetic polymers for specific biomedical applications. 

Values for water absorption by the Quinn and Paton method are different from values obtained in the same laboratory by the excess water method, particularly for the more soluble protein materials however, water absorption values determined by the "same" method by various investigators are not always similar either (Table I). 

Table 15.11 Order-of-magnitude estimate of process water and materials used in manufacture of therapeutic proteins.

Table 15.12 Comparison of small-molecules manufacture with therapeutic proteins manufacture with respect to usage of water and materials.

Protein materials that are not highly soluble at pH 8 in water are difficult to test using this method. Hydrating a protein overnight is sometimes helpful. 

Quinn, J.R. and Paton, D. 1979. A practical measurement of water hydration capacity of protein materials. Cereal Chem. 56 38-40. 

One of the major problems that a biochemical engineer will encounter is that of the stability of protein materials. The biological function of the molecule is determined by its secondary and tertiary structures and if these are upset irreversibly then the protein becomes denatured. Denaturation can occur under relatively mild conditions as proteins are usually stable over only very narrow ranges of pH (e.g. 5-8) and of temperature (e.g. 10-40°C). The boiling of an egg illustrates this point. In its uncooked form the white is a slimy clear protein solution, but under acidic conditions, or when put in boiling water, the solution gels to white solid. 

Polysaccharides probably constitute one of the most abundant fractions in soil organic matter and they are present as such or combined with the extracted humic fractions. As can be seen from the findings with soil extract and humic fractions (see Section 5.2), water-soluble materials are made up of a complex mixture of polysaccharides, proteins, phenolic and lignin-derived compounds, as well as other aliphatic materials. These compounds... 

The yellow carotene binding protein of M. sexta hemolymph is a more complicated case. Carotenes are extrerraTTy water-insoluble materials. They share this property with several other natural products including sterols, fats and hydrocarbons, all of > hich are important to insects. This property is also shared by many xenobiotics, including pesticides. Transport of hydrophobic materials within the aqueous compartments of living organisms, e.g. blood or hemolymph, is accomplished by lipoproteins. Extensive... 

The ability to make corn syrups of high quality at a low cost depends upon having a supply of low-cost, high-purity starch. The com wet-milling operation is very efficient in its separation of corn into its constituent parts of starch, water-soluble materials, protein-fiber-rich materials, and corn oil at high yield and low operating costs. 

The gum consists of a mixture of water-insoluble and water-soluble polysaccharides. Bassorin, which constitutes 60-70% of the gum, is the main water-insoluble portion, while the remainder of the gum consists of the water-soluble material tragacanthin. On hydrolysis, tragacanthin yields L-arabinose, L-fucose, D-xylose, D-galactose, and D-galacturonic acid. Tragacanth gum also contains small amounts of cellulose, starch, protein, and ash. 

Variations on the vapour diffusion method have met with considerable success. A solution of the protein containing a salt concentration approximately 10% below that needed for precipitation is equilibrated by vapour diffusion with a larger volume of more concentrated salt solution which is only slightly below the concentration needed for precipitation. With non-volatile precipitants water distils out from the protein solution to the reservoir. With volatile solvents, distillation and equilibration will proceed in the opposite direction. The hanging drop version of this method allows numerous trials of different conditions with very little protein material. Plastic tissue culture plates (for example, with 24 cylindrical wells of 2 ml volume) may be used. The precipitant solution (1 ml volume) is placed in the wells. These are then sealed with a coverslip onto which a drop of protein solution (5-20 pi) has been placed and then inverted. A drop of light oil on the rim of the well makes for an air-tight seal. The method allows ready inspection of the drops without disturbing them. 

This is the first of the coffee decaffeination patents that describe a continuous, counter-current liquid-liquid extraction. A brief description of the process is provided here. A water extract of roasted coffee beans, called coffee liquor, which contains aromas and caffeine and other water soluble components such as carbohydrate and protein materials is fed to a vacuum suipper. The extract is concentrated to about 30-50% in an evaporator-condenser and is fed to a sieve tray tower. The liquor passes across the hays in the tower downward through downspouts countercurrent to supercritical CO2 which enters the tower at the bottom and passes upward through the holes in the sieve trays. CO2 extracts caffeine from the liquor, and the decaffeinated liquor leaves the near the bottom of tower. The condensate water from the vacuum stripper prior to the tray tower is fed to the sieve trays in the top section of the tower. The water washes the caffeine from the supercritical CO2 passing upward. The caffeine-free CO2 is recycled to the bottom of the column. 

Near-infrared reflectance spectroscopy (NIRS) has been used in food industries for the determination of water, proteins, and oil content in food grains and other commodities (Williams and Norris, 2001). NIRS involves measurement of absorption spectra of a test material in the infrared region of 700 2500 nm. Compositional changes in the commodity are then correlated... 

However, one of the main drawbacks of these protein materials is their high sensitivity to water. As interaction of a protein film with water is a sum of complex phenomena, different parameters can be taken into account. The water vapor barrier properties and the plasticizing effect of water in the film (with its important influence on mechanical properties) belong to the most studied characteristics, probably because they can easily be linked to macroscopic measurements. 

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