Abstract:Pretreatment corn starch and triglyceride were used as substrates to synthesize medium or long chain fatty acid starch esters directly by lipase -catalyzed transesterification under microwave irradiation.By calculating the degree of substitution of the products，the optimum lipase and acyl donor were determined to be immobilized Candida antarctica lipase（Novozym 435，N435）and triolein（GTO），respectively.A microwaveassistant lipase-catalyed in solvent-free system was constructed.Orthogonal design was used to optimize the reaction system.The optimum conditions were as follows：starch content was 2 g；GTO content was 20 g；lipase content was 5%of the quality of pretreated starch；temperature was 60 ℃；reaction time was 2 hours，and the degree of substitution was 0.034 6 under the optimum conditions.