Properties of Gelatin Gels

Thus a full investigation of the properties of gelatin gels has to be done on samples issued from the same batch, to allow quantitative comparisons of the results. 

The physical properties of gelatin gels and their dependence on protein concentration, temperature, molecular weight, pH, and added reagents have been thoroughly reviewed by Ferry (1948a). We shall refer only briefly to supplementary work. 

Simon, A., Grohens, Y., Vandanjon, L., Bourseau, P., et al. (2003). A comparative study of the rheological and structural properties of gelatin gels of mammalian and fish origins. Macromo-lecular Symposia, 203, 331-338. 

By adopting the hypothesis that the gelatin network is formed by junction of specific loci of attraction, many of the properties of gelatin gels can be explained. 

Explanation of Various Properties. The postulate of a network with cross-links which can be dissociated by raising the temperature, whether they are single or multiple, is useful in interpreting many of the properties of gelatin gels described above. 

The characteristic properties of the gels are dependent on the nature of the fibrils, the more coarse the fibrils the more moist and elastic the gel, the finer the fibril the drier and more rigid the resultant gel silica gel may be taken as representative of a dry rigid fine fibril gel and gelatine as that of the relatively coarse elastic type. 

It will be noticed that all the properties of the gel with the exception of the turbidity and foam have minimum values at or near the isoelectric point P = 4 7, whilst these two attain their maximum values at this point. Evidently as the data for the swelling and viscosity indicate the hydration of the gelatine particles is at a minimum at the isoelectric point (see Chiari, Bioohem. Zeit xxxili. 167, 1911) where as indicated by the alcohol number it is most readily precipitated from solutions to form large aggregates to which the turbidity and the foam formation are due. 

Michon, C., Cuvelier, G., and Launay, B. 1993. Concentration dependence of the critical viscoelastic properties of gelatin at the gel point. Rheol. Acta 32 94-103. 

Chronakis, I.S., Kasapis, S. and Abeysekara, R. 1997. Structural properties of gelatin-pectin gels. Part I Effect of ethylene glycol, Food Hydrocolloids, 11 (3) 271—279. 

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