Pectin must be completely dissolve to ensure full utilization and to avoid heterogeneous gel formation. Complete dissolution requires dispersion without lumping; if pectin lumps are allowed to form they are extremely difficult to dissolve. Pectin, like any other gelling agent, will not dissolve in media where gelling conditions exist. HM-pectin thus becomes increasingly difficult to dissolve as the soluble solids in the medium increases. It is recommended that HM-pectin is dissolved at solids below 20% and preferably in water.

Dissolution with high-speed mixer

The simplest way of dissolving powdered pectin is by means of a high-speed mixer with superior shearing action. In this way 4-8% solutions of pectins are easily made. With the best mixers and using hot (min. 80C) water it is possible to make 10% solutions of most pectins.

Preblending with sugar

When dry blended with 5 parts of sugar or more, pectin may easily be dispersed into water. Fine mesh pectin may even at low concentrations dissolve readily into cold water by this method. Using regular mesh pectin and conventional stirrers it is possible to make up to approx. 4% pectin dispersions. At higher concentrations the viscosity of the batch becomes a limiting factor for homogeneous dispersion.

To ensure complete dissolution of the pectin, it is recommended that the dispersion is boiled for 1 minute. As dissolution of pectin becomes increasingly difficult at higher soluble solids, the bulk of the sugar in the recipe should not be added until the pectin is dissolved.

Dispersing in concentrated sugar solution

As pectin does not dissolve at high sugar concentrations, it is possible to make a dispersion of pectin in a concentrated sugar solution without tendency to lump formation. Depending on stirrer efficiency and process, 2 -12% pectin dispersions may be obtained by this procedure.

Complete dissolution of the pectin requires dilution with water, optimally down to 20% solids or below, followed by boiling for 1 minute.

Viscosity

Pectin solutions usually show relatively low viscosities compared to other plant gums and thickeners. Calcium or other polyvalent ions increase the viscosity of pectin solutions and low ester pectin solutions may even gel if the calcium content exceeds a certain limit. pH also influences the viscosity of pectin solutions. In a calcium-free solution the viscosity drops when pH is increased from below the pK-value to above this value. Viscosity of a pectin solution may be determined for the purpose of obtaining a measure of the molecular weight of the pectin or for evaluating the thickening effect of the pectin. In the former case, the viscosity must be determined in a calcium-free solution at a fixed pH, e.g. 4.0.