Gel strength: When the warm gelatin aqueous solution is cooled, its viscosity gradually increases. If the concentration is high enough and the temperature is low enough, the gelatin aqueous solution will be converted into gel. Gelatin gel is similar to a solid substance, which can keep its shape and has elasticity. Gelatin gel can be reversibly transformed into solution after heating.
This is an incomparable property of gelatin. The stable gel strength of gelatin solution can be determined by cooling at low temperature until gelation occurs and aging at a certain low temperature for a certain period of time. The gel strength of gelatin is related to its molecular weight and distribution, amino acid composition and technological process, and the gel strength required for different purposes is also different.
Surface activity:
There are hydrophilic and hydrophobic regions in the polypeptide chain composed of amino acids, so gelatin has appropriate surface activity like some surfactants. The results show that the surface tension of gelatin solution is related to its concentration, temperature, pH value and other factors. When the concentration of gelatin solution is lower than 1% or 1%, and the temperature is 10 ~ 45℃, the determination shall be carried out on the interface formed by the solution for no more than 1 hour.
It is found that the surface tension is the maximum between pH = 2 ~ 3, and the minimum surface tension appears at the isoelectric point. It is also pointed out that the surface tension decreases linearly with the temperature below 30℃, especially between 30 and 40℃, and further decreases with the continuous increase of temperature above 40℃, and the decline rate is faster than that of pure water. Where aging occurs, the surface tension usually decreases with time.
Refer to the above content: Baidu Encyclopedia-Gelatine Tablets