1070-4272/04/7707-1178C2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 7, 2004, pp. 1178!1181. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 7,
2004, pp. 1192!1196.
Original Russian Text Copyright + 2004 by Zemnukhova, Tomshich, Shkorina, Klykov.
AND POLYMERIC MATERIALS
Polysaccharides from Buckwheat Production Wastes
L. A. Zemnukhova, S. V. Tomshich, E. D. Shkorina, and A. G. Klykov
Institute of Chemistry, Far Eastern Division, Russian Academy of Sciences, Vladivostok, Russia
Pacific Institute of Bioorganic Chemistry, Far Eastern Division, Russian Academy of Sciences,
Primor’e Research Institute of Agriculture, Russian Academy of Agricultural Sciences,
Timiryazevskii, Primorskii krai, Russia
Received March 1, 2004
Abstract-The content, structure, and monosaccharide composition of polysaccharides recovered by sequen-
tial extraction with water, ammonium oxalate solution, and sodium hydroxide solution from wastes from
production of a series of buckwheat strains were studied. Data characterizing the raw material (ash residue),
aqueous, oxalate, and alkaline extracts (list of metals and their concentration in solution), polysaccharides
(structure, content of metals absorbed from solution), and insoluble residue of the raw material (weight of the
residue) are presented.
In the course of growing and cleaning buckwheat
grains, large amounts of wastes are formed (straw,
husk, fine particles of grains). These wastes can be
considered as valuable renewable raw materials for
chemical, food, and pharmacological industries, suit-
able for production of polysaccharides , cellulose
, dyes and food additives [5, 6], furfural , and
drugs . To develop a scheme for integrated process-
ing of buckwheat production wastes, it is necessary to
know the compositions of the raw materials depend-
ing on the plant strain and on the site of its growth.
Available data on this matter are insufficient.
In this work, we studied the composition and con-
tent of carbohydrates from husk and straw of a series
of buckwheat strains grown in Primorskii and Krasn-
Polysaccharides (PSs) were recovered from buck-
wheat husk (BH) and straw (BS) by sequential extrac-
tion with water, ammonium oxalate solution, and
sodium hydroxide solution; their qualitative and quan-
titative monosaccharide compositions were deter-
mined. Husk and straw samples (particle size >2 and
<10 mm, respectively) were washed with water and
dried in air to constant weight.
Samples (70 g) of BH and BS were sequentially
treated with water and 0.5 N solutions of ammonium
oxalate and sodium hydroxide. Water was added to a
raw material sample to S : L = 1 : 10 by weight, and
the mixture was heated on a boiling water bath for
3 h. The solution was filtered, concentrated on a rot-
ary evaporator, and centrifuged (450035000 rpm, 203
25 min) to remove the residual raw material; poly-
saccharides were precipitated with a fourfold volume
of acetone. The resulting precipitate was separated by
centrifugation, dissolved in water, and lyophilically
dried to obtain water-extractable PSs.
To the solid residue after extraction with water, a
0.5 N solution of ammonium oxalate was added to
S : L = 1 : 10, and the mixture was heated on a water
bath under the same conditions as described above.
The solution was filtered and dialyzed against running
water for 233 days and against distilled water for
132 days, after which it was concentrated on a rotary
evaporator, and a fourfold volume of acetone was
added. The precipitate was separated by centrifuga-
tion, dissolved in water, and lyophilically dried to
obtained oxalate-extractable PSs.
The solid residue after extraction with water and
ammonium oxalate was suspended in a 0.5 N NaOH
solution and heated on a water bath for 2 h. The solu-
tion was separated by centrifugation and worked up as
described above to obtain alkali-extractable PSs.
The qualitative and quantitative monosaccharide
compositions of the isolated PSs were determined
after their acid hydrolysis, which was performed with
1 N trifluoroacetic acid (TFA) at 100oC for 435h.
Analysis was performed by paper chromatography