Engineered Microparticles from Native and Modified Dioscorea hispida Starches: Structural Insights and Emulsifying Performance in Pickering Emulsions

Starch has attracted growing interest across industries such as food, pharmaceuticals, and cosmetics due to its versatile functional properties and natural abundance. As a sustainable carbohydrate source, starch is widely used in various formulations. Dioscorea hispida Dennst (D. hispida), a tuberous plant native to many regions, offers considerable potential for industrial application, given its availability and underexplored properties. This study investigates the synergistic effects of different modification techniques, including physical (heat treatment), chemical (octenyl succinic anhydride (OSA) esterification), and dual modification, on the performance of D. hispida starch as a sole stabiliser in Pickering emulsions. The modified starches were formulated as emulsifiers in Pickering emulsions and characterised for their microstructure, creaming, centrifugation stability, rheological behaviour, and colour properties. Additionally, the starches’ molecular structure, crystallinity, morphology, and thermal properties were analysed to evaluate their suitability for emulsion stabilisation. Starch modification led to an increase in starch granule size from 3.04 to 3.52 µm. Physically modified starch demonstrated the highest emulsion stability (91.80%) after four weeks, associated with smaller droplet sizes (3.90 µm). All Pickering emulsions exhibited shear-thinning rheological behaviour, indicative of their flow properties. These findings suggest that modified D. hispida starch is a promising natural, cost-effective stabiliser for Pickering emulsions with potential for diverse industrial applications. Further research is recommended to explore additional modification techniques and evaluate long-term stability under various environmental conditions.