TRADUCTION NON-DISPONIBLE

ANTI-FOAMING AGENT AND PROCESS FOR PRODUCING SAME

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
An agent for reducing foaming during fermentation of,
for example, wort to produce beer is produced by extracting ground
malt with ethanol having a concentration in excess of 75% at
approximately 50°C. The antifoaming agent thus produced is
estimated to be 5 times more active than an agent produced from
spent grains as measured by foam height.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
1. A process for producing an agent for reducing
foaming during fermentation comprising the steps of grinding
malt; and extracting the ground malt with ethanol.
2. A process according to Claim 1, wherein said
ethanol has a concentration above 75%.
3. A process according to Claim 1, wherein the
extraction is carried out at approximately 50°C.
4. A process according to Claim 1, 2 or 3, wherein
said extraction is carried out with 95% ethanol.
5. An agent for reducing foaming during fermentation
comprising an extract of ground malt with ethanol having a
concentration in excess of 75%, said extract being a yellow-
green liquid containing predominantly unsaturated fatty acids,
and some phenolic compounds and lipoproteins.

Description

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This invention relates to a process for producing an anti-
foaming agent and to an agent produced by such process. The agent
is intended to reduce foaming during fermentation, such as ale and
lage~ fermentati~ons ~nd ~artiPularly during the former,
The effect of foaming ~n fermentation processes are well
known. There are presently available many anti-foaming agents
and methods such as, for example that disclosed by U.S. Patent No.
,~, 0~5, 70q
3,085,70~, which issued to I.G. Farbenindustrie AG on June 29,1937.
m e--I.G. Farbenindustrie patent discloses a method of combating
foam during fermentation using a liquid mixture of a solid alcohol
(more than 12 carbon atoms) and a liquid aliphatic alcohol (at
least 8 carbon atoms per molecule). U.S. Patent No. 2,762,780,
which issued to S,E. Kulakow-on ~e~tembe~ 1956 di~cl~se~ an anti~
foam composition includinq sugar cane oil, an oil-soluble emulsifier,
and possibly an oil-miscible fluidizing carrier.
~ ;
U.S. Patent Nos. 3,249,515 and 3,354,050 both of which issued
to K. Rungaldier et al on May 3,1966 and November 21,1967,
respectively are of general interest because they disclose a-
mothod and an apparatus for controlling foaming by removing waste
20~ ~gas from a culture medium, separating entrained medium from the
gas and adding an antifoaming agent to the culture medium in
accordance with the rate of separation of entrained medium~ However,
the patents do not disclose any specific antifoaming agent.
A review of the above art makes it readily apparent that a
need exists for a simple, effective antifoaming agent, preferably
one which is food compatible.
The object of the present invention is to provide an anti-
foaming agent and a process for producing the agent, the process
~ being relatively simple and the agent being food compatible
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according to all criteria.
Thus, the invention relates to a process for producing an
agent for reducing foaming during fermentation comprising the
steps of grinding malt; and extracting the ground malt with ethanol.
The invention also relates to the product produced by such process,
namely an agent for reducing foaming during fermentaion comprising
the ethanolic extract of ground malt.
R. T. Roberts reported in the J. Inst. Brew, Vol. 82,96 tl976)
that an antifoam agent extracted from spent grain is very efficient
in controlling the foam head during fermentation. Applicants have
carried out experiments using spent grains from a pilot plant
in which the liquid was squeezed out manually, concent~ated using
- a rotary evaporator, and the residue was extracted with a mixture
of methanol:chloroform (1:1). After a triple extraction, the
extract was filtered through a coarse filter and concentrated to
an oily emulsion. The emulsion was suspended in water and tested
as an antifoaming agent in fermentations conducted in 2.5L tubes of
5cm internal diameter. It was established that 1 ml of this
antifoaming agent reduced a foam head to 3 cm from 16 cm in a control
experiment.
An attempt to prepare antifoaming agent using industrial
grain press effluent for the extraction failed, because an oily
emulsion with no antifoaming properties was obtained. AnalYsi~s
showed that the ma~ority of the fatty acids were saturated, whereas
agent produced from fresh spent grains from the pilot plant contains
a relati~ely high percentage of unsaturated fatty acids.
An experiment pilot plant fermentation was carried out with
antifoaming agent added to one fermenter and none in a control.
Similar foam values were obtained in each case, while beer produced
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with added antifoaming agent showed higher bitter units by 3ppm
as well as a better chill stability.
The obvious drawback of such an antifoaming agent is that
it is not food compatible due to traces of chloroform and methanol
which pass into beer.
Extraction of ground malt with 95~ ethanol at 50C produces
an antifoaming agent which is food compatible by all criteria.
The extraction is very simple. Ground malt is extracted with
95% ethanol, the yellow-green liquid is concentrated under reduced
p.ressure and suspended in water. An experimental extraction of
commercial malt yielded approximately 4% extractables.
The antifoaming agent produced by the ethanolic extraction
of ground malt is estimated to be 5 times more active than an
agent produced from spent grains as measured by foam height. The
agent contains predominantly unsaturated fatty acids and some
phenolic compounds and li`poproteins. On a commercial scale, only
25% of the ground malt could be eytract~d with alcohol and introduced
into the mash, because higher proportions would drastically impair
the conversion. It is worth noting that the extraction of only
25% of the ground malt produces sufficient antifoaming agent to
control foaming in several fermenters. When subjected to oxidation,
the antifoaming activity of the ethanolic extract is greatly reduced.
An advantage of extracting at least a part of the ground malt with
ethanol is the reduction in the trans-2-nonenal precursors formation.
The concentration of the ethanol used in the extraction should
be over 75%. The use of 50-75~ ethanol
resulted in a sticky mass from which the solvent could not be
recovered. The use of other polar solvents such as propanol or
acetone (which are not food compatible) does not provide better
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results and the enzyme inhibition is similar to that caused using
ethanol.
Counter-current extraation of ground malt with ethanol can
be carried out continuously using a screw-type extractor with a
fine mesh screen. Separation of hot ethanol from the ground malt
is simple. The ethanol can be recovered from the fermentation
gas and regenerated in the same distillation apparatus. An
estimated 5% loss of solvent can be expected and the ethanol
recovered from fermentati~n would be sufficient to offset such
loss.
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