 has closed
because as no herbicides are reg-istered for use on marigolds grown for direct
use in poultry feed or for xanthophyll production. Flowers are harvested by
hand when plants have, on the average, two or three fully developed flowers
(about 90 days after planting). Subsequent harvests (up to two) can be made at
intervals of 3 to 5 weeks, depending on plant vigor. Mechanical harvesters are
also used; they generally limit the number of harvests to one because of plant
MFP can be extracted from the meal with warm (50° to 55°C) water
(BeMiller et al. 1989). MFP was determined to be a protein-polysaccharide.
One purified fraction of the polysaccharide portion was found to contain 3.75%
galacturonic acid and neutral sugars in the molar ratio: galactose (15):
glucose (7): arabinose (3). Methylation analysis indicates a highly branched,
acidic arabinoglucogalactan. Partial characterization of the protein part
indicated the presence of at least two very hydrophobic polypeptide
constituents (Wickramasingha 1990).
The crude extract was dark, and a procedure involving an oxidative pretreatment
of the meal prior to extraction of the gum was worked out to give preparations
of minimal color (BeMiller et al. 1989). Both the crude-extract and the
bleached MFP had emulsifying and emulsion stabilization powers for limonene
equivalent to those of gum arabic at equal concentrations (1 and 2.5%) and
slightly less than those of gum arabic for olive and castor oils (BeMiller et
al. 1989). It was not, however, possible to prepare high-solids, low-viscosity
solutions of MFP and, hence, not possible to prepare concentrated emulsions.
It was hypothesized that the difference in negative charge on the two molecules
(ca. 16% uronic acid in gum arabic vs. 3.75% uronic acid in MFP) might be the
reason for their different rheological behaviors. A project was undertaken to
increase the negative charge on MFP by sulfation. The net negative charge was
increased to 14.3 mole% without decreasing its emulsion-stabilizing properties.
The reduction in viscosity was, however, only slight and remained much higher
than that of gum arabic (Medina Fuentes 1991).
MFP wascharacterized from material subjected to two different treatments before
pigment extraction, as well as from fresh petals after removal of pigments.
Storage of blossoms in silos before pigment extraction resulted in a MFP
preparation of slightly less viscosity and protein content as compared to MFP
obtained from nonensiled blossoms. The former MFP also required a slightly
higher concentration to achieve equivalent emulsion stability. MFP obtained
from fresh petals had poorer performance as an emulsifier and higher solution
viscosity (Medina Fuentes 1991). Covalently attached phenolic compounds were
present in all three sources of MFP.
The source of the meal obtained from Prodomex S.A. de C.V. (Prodomex meal) was
marigolds grown near Los Mochis, Sinaloa, México, that had been picked
both by hand and by machine. Fresh blossoms were heated, then pressed. The
resulting cake was dried, extruded into pellets, and extracted with hexane.
The source of the meal obtained from Kemin Industries, Inc. (Kemin meal) was
marigolds grown in Peru. Blossoms were stored in a silo before being pressed,
dried, and hexane extracted. The source of the fresh marigold flowers was
Alternative Agriculture Cooperative, Sedalia, Missouri; they were kept frozen
Removal of pigments from fresh flowers. Petals were separated from the
rest of the flower and extracted in a Soxhlet apparatus with methanol. The
methanol was removed, and the petals were soaked in a mixture (2:1 v/v) of
benzene and ethanol at room temperature for 1 h and then extracted again in a
Soxhlet apparatus with the same solvent. The petals were extracted twice with
hexane in a Soxhlet apparatus. The remaining colorless petals were dried at
Extraction of MFP. Dry meal (300 g) or extracted petals (55 g) were
soaked in water (1,500 ml) for 3 h at room temperature. The suspension of
swollen material was then heated for 3 h with constant stirring in a water bath
