Current Research in Nutrition and Food Science - An open access, peer reviewed international journal covering all aspects of Nutrition and Food Science

Structural and Rheological Properties of Modified Water Yam Starch Through Partial Hydrolysis and Retrogradation for Enhanced Functional Applications

Khanh Son Trinh¹, Vinh Tien Nguyen¹, Thanh Tung Pham¹ and Minh Hai Nguyen^1*

Faculty of Chemical and Food Technology, Ho Chi Minh City University of Technology and Education, Ho Chi Minh City, Vietnam

Corresponding Author E-mail: hainm@hcmute.edu.vn

Water yam starch, distinguished by its high amylose content and small granule size, presents significant potential for diverse industrial applications through targeted structural modifications. This study systematically examined the combined effects of partial acid hydrolysis and retrogradation on the structural and rheological properties of water yam starch to enhance its functional utility. Acid hydrolysis resulted in a reduction of starch chain length, as indicated by increased reducing power, while subsequent retrogradation facilitated molecular re-association, leading to an increase in relative crystallinity. X-ray diffraction analysis confirmed these structural transformations, revealing diminished peak intensities in hydrolyzed starch and enhanced crystallinity in retrograded samples. Rheological assessments demonstrated substantial alterations in pasting behavior due to these modifications. Hydrolysis lowered pasting and peak temperatures while increasing peak and final viscosities, whereas retrogradation further influenced these parameters, similarly reducing pasting and peak temperatures while enhancing viscosity profiles. All modified starches exhibited Herschel-Bulkley (pseudoplastic) fluid, with retrograded samples displaying lower maximum shear stress compared to hydrolyzed counterparts. Oscillatory rheometry revealed predominantly viscous behavior across all samples (loss modulus exceeding storage modulus), though select modifications contributed to increased elasticity. These findings underscore the efficacy of controlled hydrolysis and retrogradation in precisely tuning the physicochemical properties of water yam starch, yielding materials with thixotropic behavior and adjustable viscosity. The results highlight the potential of modified water yam starch for applications in food, pharmaceuticals, and biodegradable packaging, emphasizing its versatility as a sustainable and functional biopolymer.

Hydrolysis; Retrogradation; Rheology; Temperature sweep; Water yam starch

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