CHAPTER 12 - EXUDATE GUMS

Abstract

Publisher Summary The earliest gums used were exudate gums, because they were nearest to hand. They could be picked from trees or shrubs and easily dried and transported. The gums that arose to prominence in ancient times and are still of industrial importance are arabic, ghatti, karaya, and tragacanth. Exudate gums require much labor for incising or tapping the plant, for picking the dried or semidried gum, for sorting, bagging, and shipping, for grinding, sifting, or air classifying to remove particulate impurities after reaching the gum importers, and for further purification and spray-drying in some cases. Production of an exudate gum is a natural defense mechanism of plants that seals bark wounds. Tragacanth gum is so quickly exuded and undergoes hardening so rapidly that its protection is not as effective as the gums of other plants. Commercial exudate gums require sorting and mechanical removal of impurities. Excessive impurities and color in gums cause them to receive a low-grade classification. This chapter discusses the source, structure, properties, and uses of gum arabic, gum karaya, gum ghatti, and gum tragacanth.