Abstract: In this study, a new method was proposed to determine the stability of the emulsion formed during the microencapsulation of docosahexaenoic acid (DHA)-enriched microalgae oil and the factors influencing the emulsion stability was investigated. By comparing three different methods for determining the emulsion stability as well as by microscopic observation, we found that dilution of the emulsion with 0.1 g/100 mL sodium dodecyl sulfate (SDS) solution followed by measurement of the change in light transmittance at 600 nm at 24 h relative to that at 0 h was a convenient and accurate method. The emulsion stability and consequently the microcapsule quality were impacted considerably by wall material composition, core material proportion and total solids content. The quality of microencapsulated products prepared using a mixture of octenyl succinic anhydride modified starch and maltodextrin at a mass ratio of 2:3 as the wall material and 20% DHA-enriched microalgae oil and 33% of total solids concentrations as the core material was good and could meet the requirements of the national standards SC/T 3505—2006 Microcapsules of Fish Oil. The storage stability of DHA-enriched microalgae oil was significantly improved after being microencapsulated.

Key words: emulsion stability, transmittance turbidity, octenyl succinic anhydride modified starch, docosahexaenoic acid-enriched microalgae oil, total solids content