From Seed to Seed:
Plant Science for K-8 Educators

Pectins and gums. As we said earlier, pectin is found in the middle lamella, and acts as an intercellular cement holding adjacent cells together.

In addition to its use in jellies, pectin is a common ingredient in pharmaceuticals, cosmetics, lotions, and adhesives. It is also used to thicken ketchup and salad dressings, to help retain moisture in baked goods, and as an emulsifier in dairy products. And it's even been used in the treatment of burns.

Natural gums are found in some woody tissues and seeds. They function in the plant to seal wounds and prevent infection by microorganisms. Similar to pectins, they are commonly used to thicken and stabilize food products.

Guar gum is obtained from guar, a legume similar to its relative, the soybean. Guar gum is derived from the seed; its high viscosity and stabilizing qualities have made it useful in the manufacture of cosmetics, drugs, papers, and some foods. Agar (also called agar-agar) is another jellylike substance. Most familiar as a culture medium in biology labs, it is also used as a stabilizer in ice creams, sauces, and other foods. It is extracted from several species of seaweeds.

Gums are also used as sizing agents in textile production to stiffen fibers and facilitate weaving, and in paper production.