Astaxanthin Extract From the Biomass of <i>Haematococcus pluvialis</i> : Incorporation and Stability in Different Model Food Systems

Astaxanthin is a potent antioxidant that offers several health benefits. However, its sensitivity to light has limited its application in the food industry. In this study, astaxanthin was extracted from the freeze‐dried biomass of Haematococcus pluvialis . Chromatographic analysis revealed that astaxanthins exist as a mixture of free, monoesters, and diesters of astaxanthin in the biomass. A total astaxanthin content of 168 mg/g of freeze‐dried biomass was obtained. The extract was incorporated in different food matrix systems to identify the most suitable form for food formulations. Astaxanthin showed the best stability during storage when incorporated into nonacidified milk. Similarly, it exhibited better stability when incorporated into strong gels. Specifically, when 0.1 mg/g was incorporated in food gels of different strengths, 0.07 mg/g of astaxanthin was detected after 96 h of storage in the strong gel, compared to only 0.058 mg/g in the weaker gel. Moreover, thermal stability was evident during heat treatments encountered in food processing, such as pasteurization (65°C for 30 min and 72°C for 15), ensuring that the extract or the biomass can be incorporated into food formulations that require brief exposure to thermal energy without losing its health benefit. Finally, incorporation into an emulsion system stabilized with three cycles of sonication retained the DPPH activity, likely due to the better physical stability achieved with smaller emulsion droplets obtained during higher cycles of sonication. Incorporating astaxanthin into emulsion systems, less acidic environment and stronger gel systems could be a better strategy for the development of functional dairy products.