Pyro-dextrinization, acid hydrolysis, and cross-linking impacts on functional, pasting and structural properties of elephant foot yam starch

Abstract

Underutilized plants represent valuable reservoirs of starch, urging the need for prominent exploration of these botanical resources. The effects of pyrodextrinization, acid hydrolysis and cross linking modification on the physico-chemical, functional, structural and pasting properties of elephant foot yam (Amorphophallus paeoniifolius) starches were studied. Yam starch was cross-linked using boric acid, which is for the preparation of cross-linked yam starch. The results suggested that cross linking modification significantly decreased moisture content (10.46–1.91 %), swelling power (3.71–1.69 %) and solubility (3.58–1.51 %) of yam starch. At the same time it significantly (P < 0.05) improved amylose content (13.89–18.04 %) of starch. Increase in degree of crystallinity of all modified starches was depicted from X-ray diffractogram. Decrease in viscosity profile of modified starches was observed using Rapid Visco Analyzer. The morphology of the starch granules presented surface fissures in case of acid, whereas smooth surface of native, pyrodextrinized and cross-linked starches were observed. This research has demonstrated that chemical alterations induce notable transformations in the inherently flexible starch polymer, thereby influencing its functional characteristics and structural features. The treatment which resulted in the most thermostable starch obtained in this study was cross-linked yam starch. The ultimate goal is to offer yam starch suitable for a wide range of applications across various industries, including both food and non-food sectors positively revealing its utmost applicability for food packaging industry to be utilized as a film or coating material (cross-linked starch), fat replacers/mimickers in low-fat starch based healthy foods (acid-hydrolyzed starch).