Effect of varying degrees of succinylation on the functional and morphological properties of starch from acha (Digitaria exilis Kippis Stapf)

Scientific data on the effect of varying degrees of succinylation on starch from Acha, an underutilized source is scanty. Bridging this gap is the focus of this study. Acha starch was extracted, succinylated (succinic anhydride (SA) (3-14 g/100 g starch) and the degree of substitution determined. Proximate composition and functional characteristics of both native and succinylated starches were evaluated according to standard methods. Starch spectra and morphology were also studied. Succinylation increased (5.63-11.68%) with increasing concentration of SA. Amylose peaked at 36.42% and thereafter decreased to 28.84%. Swelling power and solubility increased in multiple folds especially at temperatures (70-90 °C) at all levels of substitution (0.1-0.20). Pasting viscosities (165.9-307.5 RVU) decreased and did not follow the order of substitution. Morphology (polygonal) and granular sizes (6-12 μm) among the succinylated and native starches were not significantly different (P < 0.05). Succinylated Acha starches hold great promise as a good and cheaper replacement for gums in Food Applications.