Pectinases

Pectic substances represent one-third of the dry substance of the primary cell walls of fruits and vegetables. They are polymers of polygalacturonic acid, varying on the degree of esterification with methoxyl or acetyl groups [Its basic structure consists of a backbone of 1,4-linked a-D-galacturonic acid (or its corresponding methyl or acetyl ester) interspersed with 2-linked L-rhamnosyl residues (side chains)]. Some of the pectic substances are soluble.

Pectinase is a generic designation for an enzyme preparation having all or some of the enzyme activities needed for the degradation of pectic substances:

• the pectin esterase activity, which de-esterifies pectins to low-methoxyl (or low-acetyl) pectins or even to pectic acid;
• the polygalacturonase activity, the pectate lyase activity and/or the pectin lyase activity which is responsible for the de-polimerization, attacking the pectin chains in different positions or in the same positions by different mechanisms.