Abstract:In view of the susceptibility to oxidation and limited application of algal oil docosahexaenoic acid（DHA），a casein-soy protein composite wall material system was constructed，and the microcapsule preparation process was optimized via the response surface methodology. Single-factor experiments were conducted to determine the addition levels of casein，soy protein，and mono-and diglycerides. A Box-Behnken design was adopted to establish an embedding rate prediction model. Experiments indicated that when the addition levels of casein，soy protein，and mono-and diglycerides were 6.8%，13.5%，and 2.2% respectively，the microcapsules achieved an embedding rate of （96.0±0.5）%，and a oxidation induction period of 17 h，which extended by 246% compared with that of unembedded algal oil. Amino acid scoring showed that the proportion of essential amino acids was 39.8%，which conformed to the Food and Agriculture Organization of the United Nations/World Health Organization （FAO/WHO） ideal protein pattern.