Viscosity gelatine solution

The Role of Alum in Historical Papermaking. .. and other Polyvalent Metals on the Viscosity of Gelatin Solutions. Journal of the Science of Food. .. WF et al. "The Effect of Alum and pH on Sheet Acidity , go to the following web site http //palimpsest.stanford.edu... 

The viscosity of gelatin solutions is vital to the control of the thickness of the cast film. Viscosity is measured on a standard 6 % w/w solution at 60°C in a capillary pipette and generally the range of 30-60 millipoise is suitable. 

In summary, the rheological studies of PATE are consistent with a proposed molecular association model for PATE solutions. Kinematic viscosity evaluation shows that at concentrations of 15% to 20% solids, a gelatinous solution results. The apparent viscosity measurements illustrate that network formation can be overcome by heating indicating that the association is electrostatic in nature. 

Figure 3. Viscosity vs. time for 1% limed bone gelatin solution treated at 24° 1°C with 0.032% HT Proteolytic Takamine enzyme The solid circles indicate measured isoelectric points of pH 4.8...

The combination of plasticity and viscosity, typical of these media, was discovered in 1889 by Shvedov for gelatin solutions and in 1919 by Bingham for... 

Bachman and coworkers (44), using ESR techniques, monitored the lifetime of free radicals in dry gelatin irradiated to approximately 50 kGy and stored in air at 20°C. Unlike the radicals in the gel, these are relatively immobile, and required several days to decay appreciably. Some were still detectable after about a month. The work and Friedberg and coworkers (45) indicates that the formation of these gelatin radicals in the dry state involves rupture of peptide bonds and that their decay does not involve combination of long chains. They found a decrease in the viscosity of solutions made from dry gelatin irradiated to a dose of 155 kGy. 

The enzyme-membranes were placed in a well-agitated 1-2 wt % pigskin gelatin (pi — 8.5 where pi is the pH of the isoelectic point of the gelatin) solution at 25°C and also at 37°C. After varying periods of time the reduced viscosity of the solution was measured with a Cannon-Ubbelohde No. 1 capillary viscometer. The decrease in viscosity of the gelatin solutions containing enzyme-membranes was compared to the viscosity decrease of control solutions and solutions to which a known amount of soluble enzyme was added. 

To test for the stability of enzyme attachment, the membrane was removed from the gelatin solution, and the solution viscosity measurements continued as a function of time. Any subsequent decrease in solution viscosity measured how much unbound or poorly bound enzyme was present on the membrane. 

With regard to the surface rheology of films adsorbed from mixed protein solutions, the situation is, in fact, even more complex than has been indicated so far. With 10 wt % casein + gelatin solutions, while there is certainly a minimum in the viscosity—composition plot over many hours (well beyond the time at which the limiting tension is reached), it disappears at very long times. Take the case of a... 

Figure 6 Casein addition to a 24 h old gelatin film at the n-hexadecane—water interface (pH 7, 0.005 M, 25 °C). The apparent viscosity is plotted against time t following exposure of 10" wt % gelatin solution to fresh interface. The arrow indicates the point at which 10 wt % casein is added. The two dashed lines represent the behavior of pure casein (C) and pure gelatin (G).

In processes illustrated on these figures, plasticizers are required for final product performance to increase elastic properties of manufactured products. Gloves are coated with rubber latex. Its viscosity is adjusted by the plasticizer. Caplet coating for pharmaceutical applications is done by immersion in a gelatin solution where water is solvent and processing plasticizer. 

Actual phenomena are, moreover, complicated by time factors which may be embodied in the term hysteresis. If the conditions in a macromolecular solution are suddenly changed (e.g., by addition of a non solvent or by a change of temperature) a certain time elapses before the new equilibrium condition is reached. This is also illustrated by recent experiments on the influence of ultrasonics on the viscosity of solutions of gelatin in water, rubber in toluene etc. If such solutions are subjected to the action of an ultrasonic field of moderate intensity, their viscosity measured at once after the treatment is markedly less than before, but, after a certain lapse of time, reassumes its initial value (or a value very near to it) The junction points are temporarily loosened due to microscopical agitation arising from the action of ultrasonic waves, but restore themselves to equilibrium condition at low rates of flow after a certain time. 

In a study on the rheological behavior of a concentrated gelatin solution, using a rotation viscometer, it is found that in a certain concentration range the apparent viscosity q pp depends on the shear stress a as follows ... 

Stainsby, G. (1952) Viscosity of dilute gelatin solutions. Nature (London), 169, 662-663. 

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