Gums

Gums are often confused with resins, and terpenoid resins are frequently called gums commercially. In fact, only relatively recently have importers and exporters distinguished gum from resin in the naval stores industry (Chapter 7). Gum has not only been confused with resin but with latex-containing polyterpenes, for example, rubber (gum boots) and chicle (chewing gum). Clouding the issue further, a general definition of gum as "any plant substance that is both sticky and elastic as well as any glue used to bond surfaces" can be found in some dictionaries. Such definitions are not based on properties that clearly distinguish the various sticky exudates such as gum, resin, and latex (Table 1-1). Chemically, true gums are complex chains of hydrophilic polysaccharides (complex sugars) derived from monosaccharide (simple sugar) moieties such as galactose, arabinose, and rhamnose, and hence, are neither terpenoid nor phenolic in origin. Whistler (1993) described in detail the very complex structure of exudate gums.

Table 1-1

Characteristics of resins, gums, mucilages, oils, waxes, and latex. Secretory tissues are discussed in detail in Chapter 3

Table 1-1

Characteristics of resins, gums, mucilages, oils, waxes, and latex. Secretory tissues are discussed in detail in Chapter 3

Was this article helpful?

0 0

Post a comment