Marigold petals (granular), which have been fermented to
make the lutein esters extraction more effectively, were purchased
from SaiTe Natural Pigments Co. (Shandong, China)
with moisture content of 5.53 g/100 g. The raw materials
were firstly ground into powder with a size range of 0.245–
0.350 mm, and then the marigold powder was defatted by
the traditional laboratory Soxhlet-extraction with n-hexane
as solvent. The defatted marigold residue was placed at
room temperature over night to let the residual n-hexane release,
and then packaged and stored in dark at room temperature
until used.