What are the properties og Gels?
Polysaccharides, proteins or colloidal complex particles, such as caseinate micelles form gels at levels of 10% or less. Gums, pectin and gelatin form gels at levels of 1% or less. Salts and pH influence gel formation adversely or favourably depending upon the concentration. By the reduction in the number of charged particles, by the adjustment of pH or addition of salt, a sol can be transformed into a gel. Addition of sugar which competes with water in the continuous phase helps gel formation when used in the proper portion. Change in temperature has an effect on gel formation; low temperatures reduce the mobility of the colloidal molecules in the sol and increase the viscosity. This condition facilitates gel formation.
The rigidity of gel changes with time leading to syneresis, which involves release of water and contraction of gel volume. The amount of liquid released varies with the type of gel and the conditions under which it is prepared.