ion 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
at 55°C. The suspension was centrifuged at 3,000 rpm (Beckman model J-6B)
for 25 min at 22°C, and the supernatant was filtered. The filtrate was
acidified with acetic acid to pH 4.5, and 95% ethanol (3 volumes) was added in
a thin stream to the rapidly stirred solution. The precipitate was collected
by centrifugation (3,000 rpm, 25 min, 22°C) and dissolved in 0.5 liters of
water. The resulting solution was filtered through a layer of diatomite
filter-aid (Celite, Manville Products Corp.) in a Buchner funnel
The aqueous solution was passed through a column of Amberlite
IR-120(H+) cation-exchange resin to remove proteinaceous material.
All effluent with an acidic pH (pH 3) was collected and dialyzed against
distilled water. The retentate was concentrated and lyophilized
Sulfation with methyl sulfoxide-sulfur trioxide complex. MFP was
dissolved in DMSO (1 g/10 ml). After solution was complete, the reaction
mixture was cooled to 15° to 17°C. The complex (Whistler and Spencer
1961) was added, and the mixture was stirred at 15d° to 17°C for 15 min.
Ice (10 g) and water (25 ml) were added, and the solution was neutralized to pH
7 with 10% ammonium hydroxide solution. A 5% excess of alkali was added, and
the mixture was stirred for 15 min. The Prodomex MFP derivative was
precipitated with ethanol (3 volumes), redissolved, and dialyzed 24 h against a
pH 8 solution of ammonium hydroxide and 48 h against distilled water. The
final product was obtained by freeze-drying.
Sulfation with triethylamine-sulfur trioxide complex. A mixture of
triethylamine-sulfur trioxide complex (Aldrich Chemical Co.) and 250 ml of
dimethylformamide was cooled to 0°C. Prodomex MFP (1 g) was added, and the
reaction was allowed to proceed 24 h at 0°C with stirring. The material was
then dialyzed 24 h against a solution of 10% ammonium hydrogen carbonate, and
48 h against distilled water. The sulfated product was precipitated with
ethanol (3 volumes), collected by centrifugation (3,000 rpm, 25 min, 22°C),
Samples (0.05 g) were analyzed for sulfur con