Alternative Fractionation Procedures

The high capital and energy costs associated with conventional corn wet-milling, and the continued growth of the industry, has renewed interest in developing alternative starch production methods. These new processes attempt to lower capital and energy requirements and, in some cases, may result in new value-added products. The alternative processes can be divided into processes which decrease diffusion time, which use mechanical shear to enhance separation of starch and protein, and which use a different chemistry to create separation of starch and protein. 

Another way to get around the diffusional limitations of whole kernel steeping is to hydrate the corn using pressure.257,258 While pressure hydration accelerates the rate of water uptake, steeping involves more than water hydration (in conventional wetmilling hydration occurs primarily during the first 12 hours). Pressure hydration must be used in conjunction with some method to disrupt the protein matrix. The major 

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An alternative method of fraction (see Fig. 2) has been developed which takes advantage of the observation that cleavage of the single disulfide bond induces the dimer - monomer transition of fraction IV (B6, S17, S19). If the fractionation procedure is carried out in the presence of a reducing agent, such as j8-mercapthoethanol, the reduced IV can be reoxidized into the dimer form by oxygen. The choice of the method... 

An alternative cleanup procedure is the partition of the raw extract, which often contains considerable amounts of lipid material, between an organic and an aqueous sodium hydroxide phase. With this partitioning scheme, the analytes are further fractionated into estrogens and nonestrogens. The presence of phenolic groups in the molecules of estrogens such as diethylstilbestrol and zeranol ensures their complete extraction from organic phases such as chloroform or tert.-butyl methyl ether into the aqueous sodium hydroxide phase (435, 438, 447). Further purification could be accomplished by neutralization of the sodium hydroxide solution and back-extraction of the contained diethylstilbestrol into diethyl ether (435), or adjustment of the pH of the sodium hydroxide solution to 10.6-10.8 and back-extraction of the contained zeranol into a chloroform phase (447). 

Find the key components If any components have similar volatilities to one of the keys, and end up in the same product, lump them with the keys. Convert all mole fractions to the equivalent binary [Eqs, (2.46) and (2.47)], An alternative, simpler procedure is to lump all light keys and light nonkeys into a single light pseudocomponent, and all heavy keys and heavy nonkeys into a single heavy pseudocomponent, This procedure (used in Fig, 2.22) is preferred by the author and others (28), Whichever method is preferred, it must be consistently applied. 

Procedure B. The following alternative isolation procedure yields a somewhat purer product. The wet ether layer which has been washed with dilute sulfuric acid to remove amine salt is transferred to a 3-1. distillation flask, 150 ml. of 2% sulfuric acid is added, and the mixture is distilled until nearly all the ether is removed. The hot, oily layer is separated in a separatory funnel and distilled (Note 4). The yield of the fraction distilling at 215-230°/3 mm. is 64-75 g. (54-63%). After recrystallization from 750 ml. of acetone, the laurone weighs 55-65 g. (46-55%), m.p. 68-69° (Note 5). 

The powerful continued fraction procedure (CFP) described by Grosso and Pastori Parravicini in Chapter III may be used to solve Eqs. (3) and (4). An alternative approach has been provided by Ferrario et al., who have computed a variety of numerically derived orientation and velocity acFs for a simple cosine potential and the more comphcated cosinal itinerant oscillator, another RMT-allowed structure. In Chapter VI, Ferrario et al. describe deexcitation effects from the two-dimensional disk-annulus itinerant oscillator also studied by Brot and coworkers. ... 

Because the presence of free glucose in plasma or serum will continue the glycosylation process (K5), it is not feasible to store such samples unless the glucose is first removed by dialysis. Preferably, the total plasma protein must be precipitated and stored as such or with further purification alternatively, fractions may be prepared by suitable fractionation procedures and stored in solid form or reconstituted in glucose-free media. 

Route B does not strictly represent a fractionation protocol but is worthy of highlighting in the instances where an alternative rapid procedure is preferred for the analysis of total FA. Here, an acid-catalyzed transesterification can be undertaken, converting total ester-finked acyl residues directly to their methyl esters. As a byproduct, nonsaponifiable lipids are also retained in this fraction (hydrocarbons, isoprenoids) and analyzed simultaneously by chromatographic techniques. While more rapid, the technique yields a more complex sample for analysis. 

The use of DSC to investigate chemical kinetics deserves special mention. It has excited more interest and more controversy than perhaps any other area of application. It continues to generate an enormous output of literature. The basis for obtaining kinetic parameters is to identify the rate of reaction with the DSC signal and the extent of reaction with the fractional area of the peak plotted against time. It is possible to obtain the three variables, rate of reaction, extent of reaction and temperature by carrying out a series of isothermal experiments at different temperatures in much the same way as in classical kinetic investigations. The experimental procedure is not without its difficulty but the interpretation of the results is less contentious than with the alternative dynamic procedures. 

Acid-treated Florisil (magnesium silicate) is particularly useful for extracts rich in acidic lipids (Carroll et aL, 1968 Radin, 1969). A typical fractionation procedure is summarized in Table 6.4 (p. 276). In contrast to silicic acid columns, those packed with Florisil are usually eluted rapidly. Alternatively, ion-exchange chromatography (such... 

A preparation relatively low in apyrase activity may be prepared by the method of McElroy and Strehler (13), using an ammonium sulfate fractionation procedure. To obtain an active extract, 4 g. of vacuum-dried firefly lanterns is ground with sand and extracted twice with a total volume of 100 ml. of water. The solution is then adjusted to pH 6 with HCl. After centrifugation the precipitate and debris are removed and discarded. 10 g. of ammonium sulfate is added and after 15 minutes at 0°C. the solution is centrifuged and the inactive precipitate is discarded. The supernatant is adjusted to pH 7.5 and 10 g. of ammonium sulfate is added. The solution is cooled to 0°C. for 15 minutes and the inactive precipitate is again discarded after centrifuging. The supernatant is adjusted to pH 4.5 and 30 g. of ammonium sulfate is added. The supernatant is cooled and filtered, and the active precipitate is dissolved in 50 ml. of water. This preparation has a clear amber color and may be stored in small, convenient vials at — 20°C. for several years. Alternatively, the preparation may be lyophilized and kept in a deep freeze. 

Alternatively—and this procedure is recommended—remove the ether with the apparatus shown in Fig. II, 13, 4. A slightly improved yield is obtained if a short fractionating column is used. 

In an alternative procedure 26 g. of anhydrous ferric chloride replace the aluniiniuni chloride, the mixture is cooled to 10°, and the 50 g. of tert.-butyl chloride is added. The mixture is slowly warmed to 25° and maintained at this temperature until no more hydrogen chloride is evolved. The reaction mixture is then washed with dilute hydrochloric acid and with water, dried and fractionally distilled. The yield of tert.-butyl benzene, b.p. 167- 170°, is 60 g. 

The early immunoglobulin products prepared by cold-ethanol fractionation were found to be free from transmitting hepatitis infection (106,108) this was not the case with products prepared by alternative methods (109). Subsequentiy, some batches of intravenous immunoglobulin transmitted hepatitis infection (110), emphasizing the importance of estabHshing vaHdated procedures for dealing with potential viral contaminants (111). 

Dried with Linde type 5A molecular sieves or Na2S04 and fractionally distd at reduced pressure. Alternatively, it was refluxed with, and distd from, BaO. Also purified by fractional crystn from the melt and distd from zinc dust. Converted to its phosphate (m 135°) or picrate (m 223°), which were purified by crystn and the free base recovered and distd. [Packer, Vaughn and Wong J Am Chem Soc 80 905 1958.] The procedure for purifying via the picrate comprises the addition of quinoline to picric acid dissolved in the minimum volume of 95% EtOH to yield yellow crystals which are washed with EtOH and air dried before recrystn from acetonitrile. The crystals are dissolved in dimethyl sulfoxide (previously dried over 4A molecular sieves) and passed through a basic alumina column, on which picric acid is adsorbed. The free base in the effluent is extracted with n-pentane and distd under vacuum. Traces of solvent are removed by vapour phase chromatography. [Mooman and Anton J Phys Chem 80 2243 1976.]... 

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