Note: Descriptions are shown in the official language in which they were submitted.
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A SOI.VENT MIXTURE, AND A PROCESS USING S~CH A MIXTURE
FOR THE EXTRACTION OF LIPIDS AND POLYPHENOLS FROM FLAKED
SUNFLOWER SEEDS
This invention relates to a novel solvent mix-
ture which can be used for the solid-liquid extraction,
conveniently in a single-step run, of lipids and poly-
phenols from flaked sunflower seeds in order to obtain
proteinaceous concentrates.
The present invention provides a solvent mixture
composed of a hydrocarbonaceous solvent, ethanol and
water. The mixture may thus be a biphasic 3-component
mixture of solvents.
The hydrccarbonaceous solvent is preferably
an alkane, normally an aliphatic alkane, preferably one
having several carbon atoms such as normal hexane.
The hydrocarbonaceous compound can be from
40% to 70% on a volume basis relative to the total mixture
and the other two components, ethanol and water, may
vary from 60~ to 30~ on the same basis with a respective
ratio, that is, ethanol to water by volume, variable
from 95:5 to 50:50.
The present invention also provides a process
for the solid-liquid extraction of lipids and polyphenols
from flakes hulled sunflower seeds, which involves the
use, as the extraction solvent, of a solv~nt mixture
composed of a hydrocarboanceous solvent, ethanol and
water.
The solid liquid extraction process may be
carried out by any of theprocedures suggested by the
technical literature. The adoption of the procedure
disclosed in the prior Patent No. 1.119.781 of March
16, 1982 has proved to be particularly advantageous.
The solid-liquid extraction process described
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therein comprises supplying fresh solvent or solvent
mixture to one of a plurality of extraction vessels ar-
ranged in series, each of which vessels contains the
solid material and is provided with a solvent inlet, a
solvent outlet, an operating stirring means and a filter-
ing element for preventing the escape of solid material
of more than a predetermined size through the solvent
outlet, the filtering elementt extending into the vessel
in the proximity of the stirring means so that the agita-
tion of the solvent or solvent mixture by the stirring
means reduces the tendency of the solid mate.rial to clog
the filtering element; passing solvent with entrained
extracted substance~s) from the said one extraction vessel
through the other extraction vessel in series; and then,
after extraction of extractible substance(s) from the
solid material in said one extraction vessel, switching
the supply of fresh solvent or solvent mixture to the
next downstream extraction vessel, removing solid material
from said one extraction vessel, and recharging the said
one extraction vessel with fresh solid material, with
the said one extraction vessel connected in series down-
stream of the previously most downstream extraction ves-
sel.
That process makes it possible to extract a
few components with a solvent or a mixture of two or
more solvents through a number, n, of serially arranged
containers, the containers being maintained, during the
entire extraction XUTI, with their contents constantly
stirred.
The solvent (or solvents) is fed to (and with-
drawn from) the several vessels with a value of the rate
of flow (unitary) which is selected within a well defined
range, usually from 2 cubic metres p~r hour and per square
metre to 15 m3/h/m2, the flow through the serially ar-
ranged vessel being continuous.
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In practice, after having charged each ~essel
with the appropriately comminuted solid material, each
vessel is filled with solvent and tirring is started.
Fresh solvent is then fed to the first container
so that the solvent already contained in it is diluted
and the extraction becomes very efficient.
The solvent drawn from the first vessel is
sent to the next extraction vessel and the same operation
is repeated, and that operation is subs~quently and se
rially repeated for all the n extraction vessels.
Once the solid material contained in the first
extraction vessel has been exhausted (in the sense that
the extractible substance has been extracted), it is
dumped and fresh solvent is fed to that vessel, the latter
being then shifted to the last place in the series.
Feed of fresh solvent is switched from the first extraction
vessel to the next and so on.
Inasmuch as, or each vessel~ about 10~ of
the solid material (the finest portions) passes into
the solvent stream, there is the necessity of providing,
in addition to the serially arranged extraction vessels,
a ~ilter: the latter separates the solid matter entrained
by the solvent stream from the liquid phase and the extrac-
tion is completed.
The practicability and the efficiency of the
process are closely bound to a number of variables and
these must be correlated to each other.
It has already been pointed out that a basic
parameter is the specific (unitary) rate of flow of the
solvent which is fed to and drawn from every extraction
vessel: it must normally range from 2 to 15 m3/hour/m2.
Other parameters must be properly selected,
such as the height:diameter ratio of the vessel, the
geometrical characteristics of the filtering member,
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the size of the filtering member openings, the material
which composes the filtering member, the thickness of
the filtering member, the kinematic viscosity of the
slurry, and the intensity of stirring maintained in the
vessel.
The specification of the above mentioned prior
patent states that anyone skilled in the art will be
capable of selecting the appropriate values of the para-
meters enumerated above so as to optimize the process
and the efficiency of the extraction consistently with
the solid material being handled, its size, the solvent
and all the other characteristics involved.
However, the said prior patent does not contain
any hint of the possible use of a ternary mixture with
different phases, and it seems, conversely, that the
process disclosed in said prior patent finds its elective
application just in the use of ~ single solvent or of
a mixture of mutally miscible and m~tually compatible
solvents.
Surprisingly, and this is the basis of the
present invention, it has now been found that it is pos-
sible to use, to the end of simultaneously extracting
from sunflower seeds more than one undesirable component,
a mixture comprised of three solvents which are distri-
buted over di~ferent phases.
The adoption of such a mixture enables a high
extraction yield to be obtained and, if it is used in
the extraction procedure described above, such a result
is combined with the ease and appreciability of that
process.
The solid-liquid extraction process is prefer-
ably carried out within a temperature of from 20C to
50C, for a time of from 30 minutes to 6 hours and a
weight (kg)- volume (litre) ratio of the flaked seed
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to the solvent mixture ranging from 1:1 to 1:10 (that
is, froml kg to 1 litre, to 1 kg to 10 litres).
Analytical methods for the chemical characterization
of the sunflower seeds and the products obtained therefrom.
Moisture, ash and crude fibre have been deter-
mined according to the standard methods of A.O.A.C.
(Association of Official Analytical Chemists, 12th Edition,
1975)-
The proteinic contents were expressed in terms
of macroKieldahl nitrogen multiplied by the coefficient
5.70. The total lipids were determined according to
the petroleum ether method as reported in A.A.C.C. No.
30-26. The polyphenol compounds were measured with the
colorimetric method by Bittoni et al (Riv.Ital.Sost.
Grasse, 54, 421, 1977). The total sugars were determined
with the method by M. Dubois et al (Analytical Chemistry,
28, 350-356, 1968), modified in that the separation of
the individual sugars was omitted and only the total
sugar contents were considered, as present in the product.
The P.D.I. (Protein Dispersibility Index) as
used for determining the quantity of nitrogen capable
of being dispersed in water under natural pH conditions
was in agreement with the method reported in A.O~C.S.
(Me~hod Ba 10 65, Revised 1969).
EXAMPLES
A11 the operating dettails will become apparent
from the following examples which have the task of illus-
trating the present invention without limiting its scope.
EXAMPLE
Sunflower seeds, having the composition reported
on Table 1, were completely dehulled in a Hydromecanique
& Frottement dehuller and the dehulled ~eeds were flaked
to a thickness of 0.25 mm in a Diefenback L2/30/30 mill.
The product thus obtained was treated with a mixture
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of the following composition:
nor.hexane 60% by volume
ethanol 35% do.
water 5% do.
The operating conditions of the solid-liquid
extraction were the following:
filling coefficient of the extraction vessels
(weight (kg):~olume(litres) 1:4
extraction time 6 hours
extraction temperature 4 5C
extraction ratio (weight:volume) 1:7~5
TABLB
CHEMICAL COMPOSITION OF A SUNFLOWER SEED SAMPLE
moisture 6%
on dry matter:lipids 60.0
Proteins 22.0~
ash 2.9%
crude fibre 3.5%
sugars 4.4%
phenols 2.4%
other nitrogen-free esters 4.8%
;
The end product had the following chemical
composition:
moisture 6.5%
on dry matter:lipids 0.5%
phenols 0.8%
proteins (Nx5.7) 65.1%
sugars 1.9%
P.D.I. (Protein Dispers.In.) 8.9%
EXAMPLE 2
Sunflower seeds which had a specification similar
to that of the seeds of Example l and were subjected
to a treatment like that of Example 1 were extracted
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with a solvent mixture composed of:
nor. hexane 60% by volume
ethanol 30% do.
wat~r 10~ do.
under the following solid-liquid extraction conditions:
fill.ing coefficient of the extraction vessels
(weight:volume) 1:4
extraction time 6 hours
extraction temperature 45C
extraction ratio (weight:
volume) 1:7.5
The extracted product had the following
chemical composition:
moisture 7.3%
on dry matter: lipids 2.1%
phenols 0.17%
proteins (Nx5.7) S9.6%
sugars 0.6%
P.D.I. 5.3%
