Citric Acid-Esterified Ginger Starch: Preparation, Characterization, and Construction of Pickering High Internal...

In this study, citric acid-esterified ginger starches with different esterification degrees (EGSC10, EGSC20, and EGSC30) were prepared via a dry-heat method by adjusting the dosage of citric acid (10%, 20%, 30%, w/w). Their multi-scale structures were systematically characterized, and Pickering high internal phase emulsions (Pickering HIPEs) synergistically stabilized by EGSC30 and β-cyclodextrin (β-CD) were constructed. The results showed that esterification modification reduced the relative crystallinity and short-range order of starch but significantly increased the content of resistant starch (RS) and thermal processing stability, indicating that the ordered regions of starch molecules were reconstructed to form a structural system with better anti-digestion properties. With the increase in the degree of esterification substitution, the surface of starch granules gradually became rough, the particle size increased, the solubility and swelling power decreased, and the contact angle increased. EGSC30 could synergistically stabilize Pickering HIPEs with β-CD. As the total concentration of composite particles increased and the β-CD/EGSC30 mass ratio was optimized to 3:1, the droplet size of Pickering emulsions decreased, the gel strength and storage modulus increased significantly, and the system exhibited typical elastic-dominant gel properties and shear-thinning behavior, with the most compact and stable network structure. The obtained results can promote the deep processing of ginger and provide a reference for the construction of novel food-grade Pickering emulsions.