Abstract:

In this paper,firstly,by using maize starch as a raw material,small-particle starch granules were prepared by means of acid hydrolysis,octenyl-succinic anhydride ( OSA) modification and freeze-grinding.Then,the effects of acid hydrolysis time on the properties of small-particle starch and the stability of Pickering emulsion were investigated.Finally,the morphology and particle size distribution of the prepared small-particle starch were characterized by using a scanning electron microscopy and a particle size analyzer,and the application of the smallparticle starch to Pickering emulsion was investigated.The results show that ( 1) with the prolonging of hydrolysis time,the particle size of starch granules decreases significantly,and the volume average particle size reduces from 15. 6μm to 6. 6μm; ( 2) the prepared starch granules are fragmented and disperse evenly; ( 3) the degree of substitution of OSA modified starch decreases as acid hydrolysis time prolongs; ( 4) the prepared Pickering emulsion,which uses the small-particle starch as the emulsifier,possesses a stability increasing with the decrease of particle size; ( 5) the emulsifying index of Pickering emulsion decreases with the prolonging of storage time and stabilizes in the end; and ( 6) the Pickering emulsion prepared with the starch after an acid hydrolysis for 48 h or 72 h possesses good stability,for instance,the emulsifying index achieves 60% even after a storage for 30 d.

Key words: maize starch, acid hydrolysis pretreatment, octenyl-succinic anhydride modification, freeze-grinding, Pickering emulsion