Spatially selective catalysis of OSA starch for preparation of Pickering emulsions with high emulsification properties.

The traditional strategies of chemical catalysis and biocatalysis for producing octenyl succinic anhydride modified starch can only randomly graft hydrophobic groups on the surface of starch, resulting in unsatisfactory emulsification performance. In this work, a lipase-inorganic hybrid catalytic system with multi-scale flower like structure is designed and applied to spatially selective catalytic preparation of ocenyl succinic anhydride modified starch. With the appropriate floral morphology and petal density, lipases distributed in the "flower center" can selectively catalyze the grafting of hydrophobic groups in a spatial manner, the hydrophobic groups are concentrated on one side of starch particles. The obtaining OSA starch exhibits excellent emulsifying property, and the pickering emulsion has good protective effect on the embedded curcumin. This work provides a direction for the development of high-performance starch-based emulsifiers for the food and pharmaceutical industries, which is of great significance for improving the preparation and emulsification theory research of modified starch.