Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1130738
This invention relates to beverages such as beer and
wine there are more or less present certain groups of colloidal
substances which are responsible for the formation of non-biolo-
gical sediments or cloudiness in the final product. Moreover
oxidation changes in certain groups of these substances tend to
impair the organoleptic properties of beverages. Precursors
responsible for colloidal cloudiness include especially polypep-
tides, polyphenols and polysaccharides. The formation of colloi-
dal sediments or cloudiness is promoted and accelerated by the
oxidation reactions which are provoked by the presence of oxygen,
temperature conditions and certain metal ions.
To increase the colloidal stability of beverages of the
afore-mentioned types a plurality of stabilizers are used. The
purpose of the stabilizing processes is to remove high molecular
weight substances which are unstable in solutions. To reduce the
concentration of polypeptidic cloudiness precursors there are
used adsorbents based on silica gel and bentonite as well as pre-
cipitants or coagulants such as tannin and enzymatic agents ca-
pable of cleaving high molecular weight substances into low mole-
cular weight components which are stable in solution, or are evensoluble.
The concentration of polyphenol can be reduced by using
adsorbents based on polyvinyl pyrrolidone, or a precipitating
agent such as formaldehyde. To prevent any oxidation changes in
the beverages the bottling plants can be operated under carbon
dioxide protection as well as with antioxidant dopes such as as-
corbic acid, sulphur dioxide or the like.
Adsorbents such as silica gels and bentonites are in-
soluble, as it is the case with those allowable from the viewpoint
of human health protection. They are used either as constituents
of filtering materials, such as diatomaceous earth, or during the
maturation of the product, or are introduced into collecting and
1~30738
pressurized tanks prior to the bottling process. Silica gel
based adsorbents are substantially inert in respect of both the
chemical and organoleptic properties of the beverages. The use
of bentonites is frequently accompanied by some modifications of
the taste of the product such as in the case of beer, which de-
velops an earthy flavour and is accompanied by a reduction of the
foaminess.
Precipitants such as formaldehyde and the like are non-
specific stablLizers and their use in the foodstuff industry is
inadmissible under the rules of human health protection of many
countries. Enzyme based stabilizers comprise a proteolytic en-
zyme as the essential component. The active component of such
stabilizers most frequently includes papain, which is a technic-
al enzyme of vegetal origin, or another suitable protease. To
date enzymatic agents have been used in the form of soluble sub-
stances. A catalyzed reaction is stopped by adding a deactivator,
or by heating to a temperature at which the enzyme component of
the stabilizers becomes denaturized. Because they contaminate
the final product with enzymatic catalytic remnants, the soluble
enzymatic agents are also inadmissible in many countries for use
in the foodstuff industries. In spite of this fact, sometimes
the use of enzymes cannot be avoided. For example there can be
mentioned the cleavage of pectines which pectinase in juice pres-
sing processes, or the stabilization of beer with a protease ad-
ditive. Originally, enzymes of vegetal, or animal origin, such
as, for instance, amylase derlved from malt, or rennase derived
from calf gastric juices have been used.~ However, in view of a
rising demand and of the expensive production of such enzymatic
preparations, enzymes of microbial origin have been preferred to
many of those of vegetal or animal origin.
However, with some enzymatic preparations, their exten-
ded contact with the respective medium is accornpanied by further
~` 113073B
undesirable cleavage of a plurality of substrates and even by the
formation of by-products whereby the character of the final pro-
duct is modified. In other cases only a partial degradation of
the substrate is sought since further degradation would change
the taste of the product. Finally, a high concentration of cer-
tain enzymes or even some accompanying enzymes in the foodstuff
may be harmful from a hygienic viewpoint. Therefore, it is
desirable that, after having fulfilled their task, such enzymes
be deactivated as quickly as possible. In connection with the
products, which during further processing, will be subjected to
temperatures adjacent the boiling point, the heating is simul-
taneously used for deactivation of enzymes since at such elevated
temperatures their proteins become denaturized. In some cases,
however, only a short-termed pasteurization is used in order to
retain the vitamin contents such as with fruit juices, or the
taste quality of the beverage such as with beer.
Although a plurality of inhibitors are known that can
stop the undesirable enzyme activity, any addition of such agents
to the foodstuff products is out of question since they are most-
ly of toxic character.
It is an object of the present invention to provide amethod of stabilizing both the colloidal and taste qualities of
beverages such as wine and beer while simultaneously deactivat-
ing the enzymes present therein, the method comprising contact-
ing a wine or beer consisting of a liquid medium containing tur-
bidity precursors, enzymes, or both at a temperature about from
-2C to about 80C with organic polymeric substances of poly-
condensate types based on diols and dicarboxylic acids, prefer-
ably polyethylene terephthalate or derivatives thereof, and
separating such polymeric substances from the liquid medium.
In such a manner, it is possible to reduce the contents
of polyphenol precursors of colloidal cloudiness as well as to
~ . f
, ~
113~73~
deactivate the enzymes which are present thus avoiding undesir-
able beverage flavours.
The afore-mentioned polymeric material can be used as
a sole stabilizer added during any of the beverage production
steps, or in a combination with other types of stabilizers. It
can be applied as filtering material, or as a constituent in com-
bination with the other filtering inorganic or organic materials
which are insoluble in water, such as diatomaceous earth.
Furthermore it can be added in powder form prior to filtering
whereupon after a certain time, it will be separated by filtering,
centrifuginy, or sedimentation. The concentration of polyphenols
and enzymes in the beverages can be reduced by allowing the latter
to flow over a fabric produced from the respective polymeric sub-
stances, or over sheets, wherein either a pulverulent or a fibrous
polymer is pressed therein. Other possible applications consist
in allowing the solution intended to be treated to flow through
columns filled with the respective polymeric material, or through
other suitable vessels filled with an adsorbent. A]so, polymeric
adsorbent may be incorporated into a plant, such as, for example,
in the form of a pipeline through which the liquid substance is
allowed to flow into boards or reactors. Advantageously no for-
eign matter is allowed to penetrate into the beverages which prac-
tising such a process.
The afore-mentioned properties are not present with the
individual components used for preparing polymers, such as mono-
mers, or polymerization catalysts. It is only a macro-molecule
of the above type that possesses a desirable property of adsor-
bing polyphenol substances and deactivating the enzymes. By re-
ducing the concentration of the polyphenol substances in the
beverage, there is an increase not only of the colloidal stabil-
ity from the viewpoint of postponing the sediment or the forma-
tion of cloudiness but also the stability of the organoleptic
1130738
properties. sy reducing the concentration of the polyphenol com-
pounds the possibility of oxidation thereof will be decreased.
It is in fact the oxidation products of such substances that un-
desirably influence the taste qualities of the final products.
Advantageously, the proteinaceous substances are not resorbed in
the process according to the invention but remain in the respect-
ive media so that the taste qualities of the final product are
not affected.
The amount of polymeric substances depends on the de-
sired properties of the beverages to be treated and on the requestfor reducing the concentration of the precursors cloudiness, or the
concentration of undesirable enzymes, respectively, be it enzymes
of vegetal origin such as, for instance, papain, or of microbial
origin such as bacterial amylases, or pectinases.
The range of activity of the adsorbents which are added
is not limited by the temperature. The treatment can be used in
any phase of the manufacturing process, at any temperature and
at any pH value.
The following examples are given as illustrative only
without, however, limiting the invention to the specific details
thereof.
EX~MPLE 1
Deactivation of alpha-amylase BACILLUS SUBTII.IS
2.5 ml of an aqueous enzyme solution containing 5 en-
zyme units in one millilitre were increased to a volume of 5 ml
with an aqueous buffer solution of pH 5.5 after which water was
added up to a volume of 20 ml. 0.1 g of pulverized polyethylene
terephthalate having a molecular weight of 38,100 was added to
the solution followed by agitation during 5 minutes after which
the liquid was filtered. No amylase activity was found in the
clear filtrate. In the present case, pulverized polyethylene
terephthalate in combination with polybutylene terephthalate
~130738
could have been used.
EXAMPLE 2
Deactivation of PaPain
To 100 ml of an aqueous enzyme solution containing 0.2
g of papain concentrate having 2.250 enzyme units per gram there
was added 1.5 g of modified polyethylene terephthalate containing
5 mols. of isophtalic acid as modifying component whereupon the
solution was allowed to stand for 30 minutes. Within this time
interval, the enzyme activity became practically zero.
10EXAMPLE 3
Deqradation of ~ectinase activitY
Reference test:-
To 7 ml of one percent pectin solution, there was added
one millilitre of a pectinase solution prepared by dissolving 4
mg of an enzymatic preparation in 2 ml water, and clarifying by
centrifuging. Immediately after mixing in a IIoppler falling-ball
vis-cosimeter, the ball passage period was examined at a constant
temperature of 30C at three minutes time intervals. The results
were as follows:-
20Time Interval ~all Passage Period
(min.) (min.)
2.36
3 2.08
6 1.48
9 1.36
12 1.27
Test:-
To 5 ml of a pectinase solution (2 mg/ml) there was
added 0.5 g of pulverized polyethylene terephthalate in which 4%
of the terephthalate units were replaced by adipate units where-
upon the solution was agitated during 10 minutes at room temper-
ature. After xemoving the sediment by centrifugation, one milli-
1130738
litre of the clear solution was added to 7 ml of a one per centpectin solution and the viscosity was again measured at three
minutes intervals at 30C. The results were as follows:-
Time Interval sall Passage Period
~min.) (min.)
0 2.39
3 2.38
6 2.33
9 2.28
1012 2.23
When comparing the above with the reference test a sub-
stantial decrease in the pectinase activity can be observed.
EXAMPLE 4
Reduction of polyphenol concentration in beer
10 litres of beer were mixed during 30 minutes with lOg
of a pulverized copolymer having a molecular weight of 15,QOO and
prepared from ethylene glycol, terephthalate and 3.9% of sulfo-
isophtalic acid. After filtration a 13.5% polyphenol concentra-
tion decrease was found out.
EXAMPLE 5
One litre of wine was mixed during 30 minutes with 2 g
of a pulverized polymer having a molecular weight of 18,000 and
prepared from ethylene glycol terephthalate and 3.0% sulfoisoph-
talic acid. The reduction of the polyphenol concentration was
11.~2%.
EXAMPLE 6
One hectolitre of beer was filtered over a kieselgur
filter while a copolymer having a molecular weight of 14,000 and
prepared from ethylene glycol terephthalate and 3.9% sulfoisoph-
30 talic acid, was added thereto. After filtration, it was ascer-
tained that the polyphenol concentration in beer has decreased
from the original value of 235.3 to 211.56 mg/litre, i.e. by
~130~3~3
about 10 per cent. The thus treated beer proved to have a two
months colloidal stability prolongation when compared to the
reference sample. The taste qualities of beer were stabilized
during a ~ month storing period.
