Pectic Substances

Pectic Substances

 

high-molecular polysaccharides that are formed in all land plants and many species of algae. Especially large quantities of pectic substances are found in fruits, berries, flax stems, and root crops—in particular, the sugar beet. Water-soluble pectic substances are called soluble pectins, and water-insoluble pectic substances protopectins.

Pectic substances are unbranched polygalacturonides, that is, polymers of galacturonic acid in which some of the carboxyl groups are esterified with methanol. Neutral monosaccharides, such as galactose, rhamnose, arabinose, and xylose, are also present in pectic substances. The primary cell walls and the intercellular substance of plants consist mostly of protopectins; soluble pectin are found in the cell sap. Pectic substances contribute to a plant tissue’s turgor, increase a plant’s resistance to drought, and help preserve fruits and vegetables under storage conditions.

As a fruit ripens, pectolytic enzymes alter the quantity and nature of pectic substances, and this produces the characteristic softening. Higher plants, fungi, and bacteria contain the pectolytic enzymes polygalacturonase, pectinesterase, and transeliminase. Many fungi and bacteria synthesize pectolytic enzymes and thus are able to decompose pectic substances. These enzymes also determine the pathogenicity of certain micro-organisms.

Pectic substances that are extracted from plants commercially or in the laboratory are called pectins. An industrially important property of pectins is the ability of their solutions to form firm gels or, in the presence of sugar and acids, to form jellies. Thus, they are used as natural gelling agents in the food industry, for example, for preparing preserves and confectioneries. Pectins are extracted from apple pomace, the rind of citrus fruits, citrons, sugar beet pulp, and the capitula of sunflowers. Preparations that contain pectolytic enzymes are obtained from molds or from plant tissue and are used to clarify wines and juices. Pectolytic enzymes are used to process fiber plants, such as flax and hemp. Pectic substances are used in the treatment of gastric diseases and as preventive agents in certain harmful industrial conditions.

REFERENCES

Khimiia uglevodov. Moscow, 1967.
Sapozhnikova, E. V. Pektinovye veshchestva i pektoliticheskie fermenty. Moscow, 1971.
Kertesz, Z. I. Pectic Substances. New York, 1951.
Worth, H. G. “The Chemistry and Biochemistry of Pectic Substances.” Chemical Reviews, 1967, vol. 67, no. 4.
Fogarty, W. M., and O. P. Ward. “Pectic Substances and Pectinolytic Enzymes.” Process Biochemistry, 1972, vol. 7, no. 8.

E. V. SAPOZHNIKOVA

References in periodicals archive ?
The enzymes including pectinase, cellulase and/or arabinase assist in the hydrolysis of pectic substances, pectins, celluloses or hemicelluloses.
It contains about 400 g/kg neutral detergent fiber (NDF) with a unique high concentration of neutral detergent soluble fiber, especially pectic substances (about 250 g/kg) (Voelker and Allen (2003).
Pectolytic enzymes (pectinases) are the ones which catalyze decomposition of pectic substances [1].
Pectic substances are complex polysaccharides with high molecular weight [46], they form the major components of the middle lamella and primary plant cell wall of higher plants [15], these substances account for 0.
Imports of Vegetable Saps and Extracts, Pectic Substances, Pectinates and Pectates has grew month on month basis by 14.
The extraction of pectic substances was performed following the technique described by McCready and McComb (1952).
02% aqueous solution of ruthenium red to detect pectic substances (Jensen 1962).
Pectic substances were characterized by titration of acidic functions of galacturonic acid before and after saponification.
Pectin or other pectic substances are heterogeneous group of high molecular weight, complex acidic structural polysaccharides with a backbone of galacturonic acid residues linked by [alpha](1-4) linkages (Kashyap et al.
For pectic substances (acidic polysaccharides) localization, sections were stained with ruthenium red, counterstained with methylene blue and mounted in Canada balsam, and the test was considered positive if red color was observed (LANGERON, 1949).
Evaluation of two colori metric methods for quantification of pectic substances in passion fruit (Passiflora edulis)