Pickering Emulsion by OSA-modified Starch with Different Molecular Structures and Its Releasing Property

As a carrier material, starch has a wider application in the delivery of bioactive compounds. Targeting the effects of starch chain structure on the characteristics of Pickering emulsion, this study used normal corn starch (Corn) and waxy corn starch (Waxy) as raw materials, and octenyl succinic acid (OSA) modification was applied to obtain OSA modified starch. These modified starches were then subjected to acid degradation (AD) or acid-heat composite degradation (AH) to obtain four starch-based materials with different molecular structures, which were then used to prepare Pickering emulsions respectively. The structure of the prepared starch materials were characterized using fourier transform infrared spectroscopy, X-ray diffraction, and size exclusion chromatography, and particle size, ζ-potential, and releasing property corresponding Pickering emulsions were also investigated. The results showed that after acid hydrolysis, the OSA corn starch subjected to acid degradation (OSA-AD-Corn) remained some ordered structure, while its chain length distribution was more was uniformly distributed with a proportion of short chains being 90.7%±0.02%. Related with the chain structure, the OSA-AD-Corn Pickering emulsion had smaller particle sizes and a higher ζ-potential. The following in vivo digestion results showed that this Pickering emulsion had 42.86%±0.54% free fatty acid releasing in small intestine. And in terms of the release of functional components, the OSA-AD-Corn Pickering emulsion provided stable delivery of curcumin, which the releasing rate in simulated gastric fluid and small intestinal fluid being 52.48%±0.42% and 27.98%±0.22%, respectively. Compared with other starch-based materials, the OSA-AD-Corn starch sample could deliver more bioactive ingredients to the small intestinal. These results would provide information for producing appropriate carrier materials for the efficient utilization of functional compounds.