Krill oil microencapsulation: Antioxidant activity, astaxanthin retention, encapsulation efficiency, fatty acids profile, in vitro bioaccessibility and storage stability

Krill oil (KO) emulsions with a ratio of KO/arabic gum of 1:4 (w/w) were prepared and then spray dried. The effect of drying temperatures on antioxidant activity, astaxanthin retention, and microencapsulation efficiency was evaluated and microcapsules with better results were employed for further analysis. The encapsulation of KO in arabic gum was confirmed by using Fourier transform infrared spectroscopy. KO microcapsules showed eicosapentaenoic and docosahexaenoic content of 21% of the total fatty acids, low omega-6/omega-3 and SF/unsaturated FA ratios, and a bioaccessibility of 53.8% after 2 h of in vitro digestion. The effect of a(w) on color change and degradation of astaxanthin contained in KO microcapsules was evaluated during storage at 35 degrees C. Monolayer value was 3.7241 g H2O/100 g d.s. which corresponds to 0.4 of a(w). The astaxanthin degradation rate increased considerably when the KO microcapsules were stored at an aw of 0.743, under these conditions the microcapsules showed drastic changes in the color parameters.

Automated summary

Krill oil microcapsules show potential for commercial applications due to their good nutritional content, high bioaccessibility, and stability. The degradation rate of astaxanthin contained in the microcapsules increases significantly with higher water activity levels, leading to drastic changes in color parameters.