Improving the emulsification properties of corn starch by esterification combined with freeze-thawing and enzymatic treatment

In this study, high performance porous starch was prepared by combining freeze-thawing and enzymatic hydrolysis with the aim of evaluating its potential as a starch emulsifier in Pickering emulsions. The results indicate that the combined treatment significantly altered the specific surface area of starch (from 0.3257 m2/g to 1.5634 m2/g), pore volume (from 0.734 × 10−3 cm3/g to 3.967 × 10−3 cm3/g), crystallinity (from 23.35 % to 19.55 %), and the ratio of amylose to amylopectin content (from 3.44 % to 15.86 %). In comparison to native starch, the degree of substitution (DS) of the modified porous starch increased by 53.3 % to 127.6 %, and esterification was confirmed by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses. In particular, OFE (−80 °C) exhibited excellent emulsifying activity and emulsion stability due to its small particle size (6.06 μm), near-neutral wettability (74.2°) and high DS (0.034). These results demonstrate the potential of OSA-modified porous starches for emulsion stabilization. •Freeze-thawing improves the efficiency of enzymatic hydrolysis.•Combined treatment increased the pore volume and pore size of starch granules.•The prepared porous starch had a higher degree of OSA substitution.•Combined treatment changed the crystallinity and hydrophobicity of starch granules.•Highly porous, highly substituted OFE significantly improves emulsion properties.