Abstract: The structure of human milk fat is unique in that most of the C16: 0 (> 70% ) is located at the sn -2position. Therefore, lard and free - fatty acid were intersterified by Lipozyme IM so as to produce human milk fat substitute. Response surface methodololgy (RSM) design was used to design and evaluate the experiment. The optimal conditions were: watercontent, 3. 7% ; reaction temperature, 61℃; substrate ratio, 2. 4: 1; enzyme load, 10%; and reaction time, 1h. The enzyme could be reused 39hours at the optimal conditions.

Key words: Human milk , Fat substitute , Lard Response surface metyodology , Lipozyme IM , Using longevity