Guar Gum: A Versatile Industrial Plant Polymer

Guar gum is a non-ionic carbohydrate polymer derived from the endosperm of two annual leguminous plants Cyanaposis teragonalobus and Cyanaposis psoraloides. Chemically, it is galactomannan consisting straight chain of mannose units attached by β-D-(1→4) linkages, having α-D-galactopyranosyl unit bonded to poly(mannose) chain through (1→6) glycosidic links. Molecular weight of galactomannan varies ranging from 50 to 8000 kDa depending on the seeds and origin of plants; however polymer usually contains a definite ratio of building blocks, i.e., 1: 2 ratio of galactose to mannose. It is used in wide range of industries including cosmetics, paper, pharmacy, textile, adhesive, inks, lithography, paints, explosive and smoking products. In general, seed gums are non-toxic and applicable as emulsion stabilizer, thickening and gelling agents. Although, they nearly indigestible but consum in many food and pharmaceutical products as valuable additives to improve product qualities.