Fermented marigold petals were purchased from SaiTe Natural
Pigments Co. (Shangdong, China) with moisture content of
5.53%. The raw materials were crushed into fine powder with a
size range of 0.245–0.350mm. The marigold powder was defatted
by Soxhlet-extraction with n-hexane as the solvent. The
defatted power 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.