Changes in Content and Bioaccessibility of DHA, EPA, and Astaxanthin During In Vitro Digestion
The data in Figure 6 unequivocally demonstrates that the emulsion prepared by MF exhibited substantially higher levels of DHA, EPA, and astaxanthin after undergoing digestion in both the stomach and small intestine when compared to the emulsion prepared by HPH. This marked difference can be attributed to the robust electrostatic repulsion between oil droplets in the MF-prepared emulsion, which effectively reduces the transfer of oxidation processes within the simulated digestive tract. Additionally, the MF-prepared emulsion benefits from a more uniform and resilient wall material, which provides superior protection against KO degradation. Following the small intestine phase, the digesta resulting from oil lipolysis underwent centrifugation to separate the micelle phase, which contained the solubilized fraction of DHA, EPA, and astaxanthin. Bioaccessibility was determined by measuring their concentrations in both the micelle phase and the total digesta. Figure 6D clearly illustrates that the MF-prepared emulsion exhibited significantly higher bioaccessibility of DH5A, EPA, and astaxanthin. This enhancement can primarily be attributed to the emulsion’s smaller particle size, which accelerates digestion due to its greater specific surface area. This observation aligns with previous research, such as the study by Salvia-Trujillo et al. (2017), which demonstrated a significant increase in carotenoid bioaccessibility with decreasing lipid droplet size in excipient emulsions. Additionally, the MF-prepared emulsion displayed greater stability with reduced droplet flocculation, further amplifying the surface area of lipids exposed to lipase.