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Gelatin optical rotation

It has been known for many years that the gelation of gelatin is accompanied by a large increase of the optical rotation in the levo direction. Smith (17) determined the final or equilibrium values of the specific rotation by setting the gel at a temperature several degrees below the temperature of interest. After a time, the temperature was raised to the temperature of interest and when the optical rotation became constant, it was recorded. This equilibrium value of the specific rotation was almost independent of the concentration above 30° C. and below 17° C. and increased as the temperature was decreased... [Pg.30]

Experiments conducted by the authors have confirmed and extended many aspects of the work of Smith. The data involving the change of optical rotation (between 25° and 15° C.) fit straight lines when plotted as 1/(1 — D) vs. time (Figure 7), but not when plotted as In 1/(1 — D) vs. time. At the latter temperature only the data of 1% gelatin concentrations and below formed straight lines when plotted in this manner. [Pg.31]

By measuring the optical rotation as it changes with time, after a gelatin solution is rapidly cooled to the temperature of interest, and extrapolating back to zero time, one can determine the initial specific rotation. It is approximately constant with the concentration, but varies with temperature. This initial specific rotation probably represents that of the sol molecule at that temperature before it is converted into the gel form. [Pg.33]

Estimation of the Configurational Contribution to Optical Rotation for Various Gelatins... [Pg.104]

The reversion of gelatins to collagen has also been discussed with refer ence to cross-links. The denaturation of collagen results in marked changes of viscosity, optical rotation, molecular weight, volume, kinetics of proteolysis, and other properties. Under certain conditions a partial reversal of these changes can be achieved (Flory and Garrett, 1958 von Hippel... [Pg.115]

C. Robinson and M. J. Bott. Nature 168, 325-6 (1951). Optical rotation and chain folding in synthetic polypeptides and gelatin. [Pg.433]

For gelatin,160,1783 1786 melting behavior with diluent, and optical rotation, were used as fingerprints to show that individual junctions melt by essentially the same process as occurs in bulk collagen. The laws that determine the bulk behavior are so well understood that a wealth of reliable information is thereby related to the gel state. [Pg.313]

Carpenter DC, Lovelace FE (1935) The influence of neutral salts on the optical rotation of gelatine. III. Effect of the halides of lithium, sodium, rubidium, and cesium. J Am Chem Soc 57 2337-... [Pg.200]

Fig. 184. Young s modulus as a function of relative conversion a/a (finrni optical rotation) for aqueous gelatin solutions (in tripio) i eing temperature 26.9 °C. Solid lines theoretical predictions based on the cascade theory of network formation for various crosslink functionalities and maximum number of potoitial junction zones curve C, which gives the best fit, f = 6 and maximum number potential juiK tion zones = 8 [17,489j. Broken lines (a, b, c) results of calculaticms with the network model [39-44] for crosslink functionalities f = 4,6 and 8, plotted vs y/f i... Fig. 184. Young s modulus as a function of relative conversion a/a (finrni optical rotation) for aqueous gelatin solutions (in tripio) i eing temperature 26.9 °C. Solid lines theoretical predictions based on the cascade theory of network formation for various crosslink functionalities and maximum number of potoitial junction zones curve C, which gives the best fit, f = 6 and maximum number potential juiK tion zones = 8 [17,489j. Broken lines (a, b, c) results of calculaticms with the network model [39-44] for crosslink functionalities f = 4,6 and 8, plotted vs y/f i...
Djabourov et al. [458,469, 508-510] determined the relationship between viscoelastic properties and optical rotation. From optical rotation the weight fraction, %, of helices present in an aqueous gelatin system could be calculated, because of the big difference in optical rotations in the coiled and the helical (collagenlike) states ... [Pg.193]

Busnell et al. [478] investigated the prematuring effect on the gelation behaviour of gelatin solutions with the aid of viscodastic experiments combined with differ tial scaiming calorimetry and optical rotation experiments also... [Pg.196]

From their measurement of the temperature dependence of optical rotation of very dilute a-gelatin solutions, Eagland et al. [477] conclude that AH of... [Pg.265]

To find out, if there is a correlation between the content of the network junctions and the helical content of the mixture, we have combined kinetic measurements of the mechanical and optical properties. For this reason we have constructed a special measuring cell for the simultaneous detection of the complex shear modulus and the optical rotation of polymer/solvent systems, e.g. gelatin/water up to 4 wt.% of gelatin. [Pg.324]

This work mainly concerns with the question, if there is a correlation in gelation kinetics between network formation and the increasing helical content of the mixture. For this reason we have examined the time dependence of the mechanical parameters G and G" and the specific optical rotation during the gelation process, which has been induced by a temperature jump from 313 K to 293 K. The physical values G, G" and are plotted versus the time for a gelatin/water mixture of... [Pg.325]

In addition, the native collagen content can be calculated for soluble type I collagen by determination of the loss of optical rotation during the transition to gelatin. Nagelschmidt and Viell (1987) report that at 365 nm the specific optical rotation of type I collagen is between -1029° and -1334° while after denaturation it is between -382° and -509°. [Pg.328]


See other pages where Gelatin optical rotation is mentioned: [Pg.86]    [Pg.108]    [Pg.31]    [Pg.32]    [Pg.34]    [Pg.211]    [Pg.227]    [Pg.80]    [Pg.105]    [Pg.106]    [Pg.108]    [Pg.110]    [Pg.111]    [Pg.112]    [Pg.113]    [Pg.115]    [Pg.125]    [Pg.127]    [Pg.392]    [Pg.239]    [Pg.310]    [Pg.315]    [Pg.139]    [Pg.185]    [Pg.173]    [Pg.179]    [Pg.184]    [Pg.193]    [Pg.193]    [Pg.193]    [Pg.193]    [Pg.249]    [Pg.323]    [Pg.272]   
See also in sourсe #XX -- [ Pg.125 ]

See also in sourсe #XX -- [ Pg.7 , Pg.306 ]




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Optical rotation

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