Enhancing starch properties through dual modification: Ultrasonication and acetic acid treatment of non-conventional starches

Abstract

This study investigated the effects of ultrasonication (US) and acetic acid treatments on starches extracted from non-conventional sources: elephant foot yam (NES), cassava (NCS) and sweet potato (NSP). The starches underwent ultrasonication at 40°C for 3, 9, and 15 min, followed by acetylation, with native starches used as control. The morphological, physicochemical, and functional properties were comprehensively analyzed. Results revealed that increased treatment time significantly (p<0.05) affected the starches functional properties, morphology and crystallinity. Amylose content was highest in NES (22.85 %), followed by NSP (21.05 %) and NCS (19.28 %). Following dual modification, a significant reduction in amylose content was observed in ultrasonic-assisted acetylated starches. Morphological analysis revealed granular aggregation, surface changes, and the formation of pores and cracks. X-ray diffraction (XRD) patterns demonstrated that NSP and NES starches exhibited major peaks characteristic of C-type starches, while NCS starches displayed an A-type pattern. Following ultrasound-assisted acetylation, the crystalline structures of all starches remained largely unchanged, although relative crystallinity slightly decreased compared to native starches. The oil absorption capacity and tap density of NES increased with dual modification, suggesting enhanced hydrophobicity. These findings highlight the potential of dual modification to improve starch properties for industrial applications, including confectionery, edible films, tablet binders, and encapsulation.