Pectin is a solid powder, off white in color.
Pectin is practically odorless. It is mucilaginous.
Pectin is stable at ordinary conditions, becomes unstable in excess heat. Pectin is soluble in pure water, partially soluble in cold water. It is insoluble in alcohol and organic solvents. When pectin is mixed with alcohol or organic solvent and mixed with water it is soluble, whereas di- and tri- salts are weakly soluble or insoluble.
Pectin is combustible at higher temperatures, because of this it must be kept away from heat and any source of ignition.
Dry powered pectin, when added to water, has a tendency to hydrate, very rapidly, forming gels.
Dilute solutions are newtonian, but at a moderate concentration, they exhibit non-newtonian, pseudo plastic behavior characteristics.
Viscosity, solubility and gelation are generally related (e.g. factors that increase gel strength will increase the tendency to gel, decrease solubility, and increase viscosity and vice versa).
Coulombic repulsion is present between the carboxylate anions which prevent the aggregation of the polymer chains.
Another property of pectin which plays a major role in most of its applications is its pH. When pH is lowered, ionization of carboxylate groups is suppressed, and this results in reduction in hydration of carboxylic acid groups. At higher pH the degree of methylation will be greater. At a pH of 5-6 low methoxylated pectin is stable, but high methoxylated pectin is stable only at room temperature.
Pectin does not undergo polymerization but undergoes depolymerisation. Depolymerisation occurs when pectin molecules are treated with dilute acids at higher temperatures. They break into smaller fragments. The pectin which is dissolved in solutions gets decomposed spontaneously by deesterification as well as by depolymerisation. These rates depend upon the pH and on temperature. Deesterification is favored by low pH. Maximum stability of pectin occurs only at pH 4.
The other properties which influence the wide spread applications of pectin are, degree of methoxylation, degree of esterification and degree of amidation.
Generally pectin is valued by the pectin grade, defined as number of pounds of sugar that one pound of pectin can carry in a jelly.