Impact of chemical modifications in pilot-scale isolated sorghum starch and commercial cassava starch

Abstract

The aim of this work was to evaluate the impact of different chemical modification methods on starch from different botanical sources. Brown and white sorghum starch was isolated throughout a time saving process and avoiding the use of dangerous compounds. Brown and white sorghum and commercial cassava starch were treated using acetic acid, acetic anhydride and octanoyl chloride. Its chemical, morphological and thermal characterization was afterwards carried out. The modifications reduced amylose content and increased damaged starch. Both acetylation and acid treatment produced no significant changes in the size and shape of granules; yet, they increased superficial pores. SEM observations supported the results, indicating that octanoyl modification causes a partial destruction of the granule structure. Thus, particle size distribution changes significantly. Crystallinity degree decreased with all the modifications. However, the effect was more pronounced in octanoyl esterification. In general, modifications increase the water absorption of the native starch but no considerable effect was found over oil absorption, and gelatinization parameters were significantly altered as a result of modifications. Starch from these subtilized sources was successfully modified, which could arouse interest in its industrial production.