Coacervation basis

This coacervation process forms the basis for the self-assembly, which takes place prior to the crosslinking. The assembly of tropoelastin is based on an ordering process, in which the polypeptides are converted from a state with little order to a more structured conformation [8]. The insoluble elastic fiber is formed via the enzymatic crosslinking of tropoelastin (described in Sect. 2.1). Various models have been proposed to explain the mechanism of elasticity of the elastin fibers. 

Aqueous Solutions The transition temperature above which a non-ionic surfactant or wax loses some of its water solubility and becomes ineffective as a surfactant. The originally transparent surfactant solution becomes cloudy because of the separation of a surfactant-rich phase. Cloud points are typically reported on the basis of tests for a specified surfactant concentration such as 1 mass%. See also Coacervation. 

All of the materials containing two polymers can be broadly classified as either polymer blends or graft copolymers on the basis of the absence or presence of covalent chemical bonds between the two species. For special purposes, it has also been of interest to mix solutions of anionic and cationic polymers. Such materials coacervate, and form association complexes with ionic bonds. Because of the impermanent nature of such bonds, we choose to classify such materials with polymer blends. Examples of these materials are given by Leitz and Shorr (1972) and Eisenberg and King (1972). These materials are sometimes of interest because of their salt transport properties (Leitz and Shorr, 1972). See Section 9.5. 

Holwerda comes on the basis of this and other evidence to the view that the primary separation of the edestin is not comparable with ordinary coacervation but that forces producing order play a part right from the start. With too much NaCl in the system these are too weak to make themselves distinguishable at the periphery in a polyhedral shape. 

Although the theory of complex coacervation in the narrower sense (p. 370 2o) was originally developed on the basis of the assumption that sols are in principle two phase systems, good reasons were present for assuming that a theory which is based on the representation of the biocolloid sols as true solutions would contain a greater element of truth. 

The microscopic picture however (Fig. 6b) makes the impression that the gelation vacuoles are attached with a relatively broad basis, but this could be the result of a change in wetting properties of the G 4- A 4- n coacervate after solidification of the G 4- N 4- a coacervate, as discussed in 1. 

Fractionation. Polymers may be separated on the basis of molecular weight by precipitation or phase-separation techniques (146-149). The polymer that is originally in solution separates on the basis of molecular weight when the thermodynamic quality of the solvents is changed, ie, by changing the solvent composition or temperature. The principal techniques are fractional precipitation and coacervate extraction, both solution-based (Fig. 3). The former is based on the removal of material from the polymer-rich precipitated phase and the latter on the removal of fractions from the polymer-lean solution phase. Computer simulations and experimental results have shown the coacervate extraction technique (150) to yield narrower molecular weight distribution fractions than the fractional precipitation method (151-153). 

The primary considerations for the flavor industry are the use of any meat or meat byproduct in process flavors, gelatin in process flavors or coacervation processes, and the use of alcohol as a component on any basis in a flavoring are all prohibited. There are various organizations that oversee halal certification of foods. Unlike the kosher certification, halal certification is younger and thus less well organized. Two organizations that come up on a web search are IFANCA (The Islamic Food and Nutrition Council of America, 5901 N. Cicero Avenue, Suite 309 Chicago, IL, 60646) and Halal Transactions, Inc., P.O. Box 4546, Omaha, NE, 68104). 

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