Astaxanthin, DHA and EPA Content and Bioaccessibility
The content of astaxanthin, DHA, and EPA was individually determined
following salivary, gastric, and intestinal digestion, employing the
methods described previously. After in vitro digestion, a portion
of the digesta was subjected to centrifugation at 8000 rpm/min at 25°C
for 30 min. The resulting clear middle layer, formed after
centrifugation, was assumed to contain the micellar fraction that
solubilized astaxanthin, DHA, and EPA. This micellar phase was extracted
using the wet oil extraction method and prepared for HPLC analysis.
The actual content of astaxanthin, DHA, and EPA was calculated based on
their respective standard curves. Subsequently, the bioaccessibility was
determined. The effective bioaccessibility (%) of astaxanthin, DHA, and
EPA was calculated using the following formula: Astaxanthin/DHA/EPA
bioaccessibility (%) = 100 × Cmicelle /
Cinitial, where Cmicelle represents the
concentration of astaxanthin, DHA, and EPA in the micellar fraction,
while Cinitial represents their initial concentrations
in the samples.