Effect of sustainable chemical modifications on pasting and gel properties of Sorghum and Cassava Starch

Abstract

Starch isolated from two different sorghum hybrids and a commercial cassava starch were modified in order to assess the improvement in rheological and thermal properties that could be produced by sustainable methods. Modifications were acetylation with acetic anhydride, hydrolysis with acetic acid, and esterification with octanoyl chloride. All sorghum starch paste exhibited higher syneresis than cassava ones and acetylation slightly improved water retention. In general, pasting profiles were significantly altered throughout modifications and the paste textural properties and rheological results suggested a physical gel behavior. Cassava and white sorghum unmodified gels showed higher values of textural parameters than those of brown sorghum. The flow data were adequately fitted by the power-law model (R2 > 0.96) with flow behavior index < 1. The acetylation, acid treatment, and octanoyl esterification of cassava and sorghum starch resulted in significant changes in water interaction, indicating a wider range of properties.