Preparation method of modified starch-lipid binary complexes

A preparation method of modified starch-lipid binary complexes, comprising:

• (1) preparing a modified starch with octenyl succinic anhydride comprising taking corn starch into an aqueous ionic liquid to prepare a 10 wt % starch suspension, adjusting pH of the system to a pH of 8.0-8.5 by adding a sodium hydroxide solution with a concentration of 0.5 M, weighing octenyl succinic anhydride that accounts for 1%-9% of the mass of the starch on dry basis and adding into the starch suspension drop by drop within 2.5 h at a temperature of 25° C. to perform a modification reaction for modifying the corn starch, maintaining the modification reaction for 5 hours at a stirring rate of 200 rpm, adjusting pH of the reaction system to a pH of 6.0, centrifuging and washing the reaction mixture for 3 times, where the centrifuging is carried out for 10 minutes at a centrifugal force of 5,000 g, and the washing is carried out with distilled water and 70% ethanol alternately, then drying via vacuum at 40° C. for 12 hours to yield the modified starch with octenyl succinic anhydride, wherein the aqueous ionic liquid is prepared by mixing a 1-ethyl-3-methyl imidazole acetate ionic liquid with water at a mass ratio of 2:8;
• (2) preparing a modified starch-lipid suspension comprising adding the modified starch with octenyl succinic anhydride prepared in step (1) into distilled water to yield a 7-20 wt % suspension by stirring, then adding a lipid to yield the modified starch-lipid suspension by stirring, wherein a mass ratio of the lipid to the modified starch on a dry basis is 1:(10-200), and the lipid is a long-chain fatty acid or a glyceride;
• (3) heating the modified starch-lipid suspension obtained in step (2) in a magnetic stirring temperature control water bath for starch gelation and conducting freeze-drying and grinding, comprising 3A) in a preheating and uniform mixing stage, subjecting the modified starch-lipid suspension to preheating and stirring at a temperature of 50° C. at a stirring rate of 200 rpm for 2 min;
• 3B) in a heating and reaction stage, raising the temperature to 100° C. at a heating rate of 25° C./min, and carrying out a complexing reaction at a stirring rate of 260 rpm for 1 hours;
• 3C) in a cooling and formation stage, lowering the temperature to 25° C. at a cooling rate of 10° C./min and a stirring rate of 100 rpm to yield a gelatinized sample of a modified starch-lipid complex;
• and 3D) in a sample treating stage, rapidly placing the gelatinized sample in liquid nitrogen for cooling for 5 min, freeze-drying for 24 hours, grinding with a high-throughput liquid nitrogen freezing grinder with a rotor size of 6*Φ0.9 cm at a rotation speed of 10 cps for 10 min, and then sieving with a 100-mesh sieve to obtain the modified starch-lipid binary complexes.