Emulsifying Properties of Hemicelluloses

Abstract

This chapter focuses on the emulsifying properties of hemicelluloses. Hemicelluloses are gummy polysaccharides of complexity between gum and cellulose. Based on the major monosaccharide constituents of their backbone, hemicelluloses can be classiied into xylans, mannans, xylogalactans and xyloglucans. Their sources include seeds, husks, straws, leaves and wood. Hemicelluloses bring about emulsiication by viscosity modi- ication and by formation of multilayered ilms around each globule of the dispersed phase. They have strong emulsifying power but are somehow limited by batch-to-batch variation and susceptibility to microbial and chemical degradations. These limitations are overcome by the use of puriied and semisynthetic derivatives. Hemicelluloses and deriv- atives herein considered for their emulsifying properties include those from barley straw, wheat straw, corn iber, locust bean, guar, soy bean, konjac, prosopis seed and afzelia seed. Hemicelluloses, as plant polysaccharides, are only second to cellulose in terms of abun- dance. They have superior emulsifying properties compared to the typical gums. They are amenable to many chemical modiications for the enhancement of stability and for the improvement of emulsifying properties. Hemicelluloses were not given adequate aten- tion in the past; but this chapter shows that they are potentially useful emulsifying agents. Keywords: