Method for preparing fatty acid starch ester

The invention discloses a method for preparing a fatty acid starch ester. The method comprises the following steps of: adding dried starch raw materials into ionic liquid 1-butyl-3-methyl imidazolium chloride, stirring at the constant temperature of 100-140 DEG C under nitrogen protection, cooling, adding absolute ethyl alcohol for washing, centrifuging, removing the supernatant, and drying the obtained precipitate; adding the dried precipitate into 1-butyl-3-methyl imidazolium tetrafluoroborate, adding lipase and fatty acid under nitrogen protection, reacting for 1-5 hours so that the reaction is ended, cooling the solution, adding absolute ethyl alcohol for washing, centrifuging, removing the supernatant, drying the obtained precipitate at the temperature of 35-50 DEG C for 40-48 hours, thereby obtaining the fatty acid starch ester. The fatty acid starch ester is high in additional value, nonirritant and easily degradable, has good thermoplasticity, hydrophobic property and other excellent performances and can be widely applied to the fields of foods, textiles, medicines, daily chemicals and the like.