Effect of pretreatments on extraction of pigment from marigold flower.

Marigold flower (Tagetes erecta L) is one of the
richest sources of xanthophylls. An enzymatic pretreatment
method was developed for improved extraction of pigments
from marigold flowers. Pretreatment with enzyme solution
increased the diffusion coefficient from 1.56 x 10-9 m2/s to
4.02 x 10-9 m2/s and mass transfer coefficient from 0.14 h-1
to 0.36 h-1 coefficients. At the same time, dry yield, resin
yield and pigment yield were also found to increase along
with increased retention of colour. Sodium hydroxide or
citric acid pretreatments increased the diffusion coefficient
during drying, but resulted in lower dry yield due to loss of
soluble compounds whereas, pigment yield was higher as
compared to control. The enzyme treated and air dried
sample, stored at 4 °C was found to be the most stable, as
indicated by a low (0.0006 day−1) degradation constant.
Pretreatment of marigold flowers with an aqueous enzyme
solution (0.2%) results in improved resin, pigment yield
and retention of pigment during storage. Pretreatment of
marigold flowers with sodium hydroxide citric acid
followed by hydraulic pressing resulted in a significant
reduction of water and also indicated improved dry yield,
resin yield and pigment yield as compared to control
sample.