Abstract:

In order to optimize the formula of micro-algal microcapsules, the effects of emulsifier, casein, cyclodextrin on microencapsulation efficiency of micro-algal oil were explored using response surface methodology. Results indicated that the optimal formulation for micro-algal oil microcapsules were 3.98% emulsifier, 3.52% casein, 11.1% cyclodextrin and 30% microalgal oil as the core-material, respectively. The microcapsulation efficiency of micro-algal oil reached up to 93.37% at this optimal condition. Compared with the control samples, the peroxide value (POV) of total oil in microcapsules remained one third after accelerated oxidation at (60 ± 1) ℃ for 14 days, which revealed a promising oxidation stability of micro-algal oil in microcapsules. The retention rate of DHA in formula milk powder containing micro-algal oil microcapsules was up to 91.06% after storage for 1 year under the conditions of vacuum packaging, room temperature and lightlessness. Therefore, micro-algal oil microcapsules exhibited an excellent oxidation stability and storage stability.

Key words: micro-algal oil, docosahexaenoic acid (DHA), microcapsule, response surface methodology, stability