Effects of differential degree of chemical modification on the properties of modified starches: Sizing

Structural and behavioral properties of modified starch by chemical means such as acidification, acetylation, hydroxypropylation, cross-linking/phosphorylation, maleation/succinylation, cationization, amphoterism, and the effect of differential degree of chemical modification of starches in relation to sizing have been reviewed. Since native starch is relatively latent, it requires modification to alter its structure and introduce essential properties. Factors such as concentration, modifying agents, time, pH, and reaction medium affect the extent of starch modification. The degree of chemical modification (substitution/cross-linking) reflects the level of starch resistance or liability in their applications. The behavior of some modified starch at different DS has specific functionality on the sizing properties of starch. Satisfactorily modified starch size offers good warp yarns that drastically reduce yarn breakages during mechanical operation; hence, increasing productivity. Preference could be made to lower DS/DC of acidified, cross-linked, acetylated, maleated/succinylated, and electro-neutral amphoteric starch for effective sizing while highly hydroxypropylated starch grants good viscosity.