Impact of ultrasonic, chemical, and thermal treatments on the structural, physicochemical, and techno-functional properties of Ibes bean (Phaseolus polyanthus) starch

The growing interest in sustainable and functional ingredients has driven the exploration of non-conventional starch sources, particularly from underutilized legumes. Phaseolus polyanthus (Ibes bean), a native crop from southern Mexico, represents a promising alternative due to its high starch content and local significance. This study evaluated the effect of ultrasonic, chemical, and thermal treatments on the physicochemical, functional, structural, and rheological properties of starch extracted from Ibes beans. Native starch was isolated and subjected to each modification method. Functional properties, color parameters, amylose/amylopectin ratio, FTIR and SEM analyses, and viscoelastic behavior were assessed. All treatments increased apparent amylose content and altered hydration behavior. Dry heat treatment (DHS) caused the most pronounced modifications, with increased water solubility (21.12 %) but reduced swelling power (7.95 g/g) and viscoelastic strength. In contrast, ultrasound-modified starch (UMS) enhanced swelling capacity (10.06 g/g) and preserved a stronger gel network. Acid hydrolysis (AMS) also improved paste clarity and reduced color difference, suggesting microstructural reorganization. These changes were associated with altered short-range molecular order and amylose-amylopectin interactions. The findings demonstrate the potential of Ibes bean starch as a versatile and modifiable biopolymer. The modified starches exhibit properties suitable for specific food or material applications, such as thickening, encapsulation, or biodegradable films. This work contributes to the valorization of native crops and supports the development of sustainable starch-based ingredients using clean and scalable technologies.