ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 12, pp. 2104!2106. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + E.V. Churilina, Ya.I. Korenman, P.T. Sukhanov, V.M. Bolotov, G.V. Shatalov, 2007, published in Zhurnal Prikladnoi Khimii,
2007, Vol. 80, No. 12, pp. 2026 !2028.
AND INDUSTRIAL ORGANIC CHEMISTRY
Recovery of Anthocyan Dye from Aqueous-Salt Solutions
with Polyethylene Glycol PEG-5000
E. V. Churilina, Ya. I. Korenman, P. T. Sukhanov, V. M. Bolotov, and G. V. Shatalov
Voronezh State Technological Academy, Voronezh, Russia
Voronezh State University, Voronezh, Russia
Received February 9, 2007
Abstract-Extraction with PEG-5000 was studied as a method for recovering and concentrating a natural
anthocyan dye from sodium and ammonium sulfate solutions. The effects of the type of salt cation, pH, and
addition of aliphatic alcohols on the dye recovery were examined.
The involvement of synthetic dyes in carcinogenesis
makes natural dyes, which are harmless and, what is
more, useful, preferable for food and pharmaceutical
industries [1, 2]. Among these natural dyes are red
pigments (anthocyans) causing coloration of red wines
and fruit juices. Anthocyans belong to the group of
phenolic flavonoid compounds :
are H, OH, or OCH
, and R
atoms or carbohydrate residues.
Anthocyan extracts contain biologically active
components (vitamins, microelements, organic acids)
and aliphatic alcohols, added to aqueous solutions
to facilitate dye extraction from the vegetable raw
For recovery and concentration of the natural dyes
from aqueous solutions, the extraction with water-
soluble high-molecular-weight compounds forming
a separate aqueous-organic phase in the presence of
salting-out agents shows promise. Polyethylene gly-
cols (PEGs), which are nontoxic compounds used as
thickeners and binders in pharmaceutical industry and
cosmetology , belong to such polymers. Two-phase
aqueous systems based on PEG are successfully used
in extraction recovery and separation of organic and
inorganic substances of various classes .
The goal of this study was to optimize the condi-
tions of the recovery and concentration of the antho-
cyan dye from aqueous solutions, using dye extraction
with PEG-5000 from aqueous-salt solutions.
THe anthocyan dye was recovered from black-cur-
rant berries with ethanol at 50355oC by the known
method . The dye distribution was studied in sys-
tems constituted by an aqueous solution and solution
of sodium or ammonium sulfate. The polymer manu-
factured by Loba Chemie Co. with a molecular weight
of 5000 and salting-out agents and aliphatic alcohols
of chemically pure grade were used.
A 15-ml portion of an anthocyan dye solution con-
(40 wt %) or Na
(15 wt %)
was placed in a flask with a ground-glass stopper,
3 ml of PEG solution (0.1320 wt %) was added, and
extraction was performed on a vibromixer for 335 min
(time in which the phase equilibrium is attained).
The efficiency of the extractive recovery of the dye
was evaluated by the degree of dye recovery, R (%):
and A are the optical densities of the aque-
ous solutions before and after extraction.
The optical densities of the solutions were measured
on a KFK-2MP photocolorimeter at 490 nm using op-
tical cells of thickness 1 and 3 cm. The content of
the red pigment in the anthocyan dye was determined