Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
METHOD FOR PRODUCTION OF MALT
BACKGROUND OF THE INVENTION
This invention relates lo a method for production
of malt. `
Malt, which is useful as a starting material for
brewing,is being produced by a method which comprises
subjecting cereal grain for malt to steeping and
ge~mination. In such a conventional process, the quality
of the malt is lowered when the yield of the malt is
increasad. Therefore, a method which compxises applying
gibberellln to the cereal grain in the malting process
step to shorten the period for germination and thereby to
seek an increase in malt yield and decrease in cost and,
moreover, to prevent deterioration of quality has been
reduced to practice. Gibberellin is also being utilized
to produce malt of high quality from barley of low
~uality.
The use of gibbexellin, however, is not desirable
because the woxt prepared rom the malt produced by the
use of gibberellin has defects such as the deepened
color of wort.
In order to solve such problems wi~h respect to the
use of gibberellin, KBrO3 has been practically used in
combination with gibberellin. However, K~rO3 is said to
have mutagenicity, and thus the use thereof is not
desired from the viewpoint of food hygiene. The use
of various chemicals other than KBrO3 has also been
proposed, but in all these ca,ses the use of these
chemicals has low practlcal value because of fcod
hygiene problems and the like.
SUM~ ~ QF THE INVENTION
It is an object of the present invention to solve
the aboYe described problems. This obejct has been
accomplished by the use of abscisic acid or a
functional derivative thereof instead o~ KBrO3 or other
chemicals.
Thus, ~he method for produc~ion of malt in
accordance with the present invention comprises subjec,-
ing cereal grain for malt to steeping, vi~.. water-
absorption,and germina~ion and is characterized in that
an abscisic compound which is abscisic acid or a
functional derivative thereof is applied to the cereal
grain which is in the steeping process or the germina-
tion process.
A feature of the present invention resides in the
use of abscislc acid or a functional derivative thereof,
which can be used if so desired in combination with
other chemiclas as lcng as this feature is not impaired.
One group of such chemicals is gibberellin or a
functional derivative thereof.
Thus, -the method for production of malt in accord-
ance with the presen. invention in another aspect thereof
comprises subjecting cereal grain for malt to steeping
and ~ermination, and is char~cterized in that both
the abscisic compound and a gibberellic compound which
is gibberellin and/or a functional derivative thereof
are applied to the cereal grain which is in a process
stage of steeping or ger~ination.
The term "cereal grain for malt" herein refers to
cereal grain for use in brewing. Among -the grains that
so named are barley, wheat, rye, oats, and various
other cereal grains such as millet and soryham. Barley
is the most typical~
DETAILED DESCRIPTION OF THE INVENTION
.. ... . _ _
Abscisic acid to be used for malting in accordance
with the present invention is not a syn~hetic compound
but a plant hormone which is g~nerally contained in
cereals, vegetables, fruits and the like. Thus, there
is no food hygiene probl~m or risk in operations as
in the case o~ K~rO3 and other chemicals. Furthermore,
abscisic acid or the like can exhibit a marked effect
at a very low concentration in comparison wikh KBrO3 and
the like. For example, KBrO3 has been used in a quantity
o~ about 100 ppm on the basis of barley weight, but
abscisic acid or the like is effective even in a quantity
of 0.1 to 1 ppm, as described ~elcw in detail.
By the acldition of abscisic acid to barley in the
course o th~ malting process, the growth of rootlets is
inhibited to increase the yield of maltO ~t the same
time, excessive decomposition of proteins is controlled,
and the amount of free amino acids is decreased in the
wort prepared from the resulting malt because formation
of protease is innibited. Further, the degree of
coloring wort due to formation of melanoidine is de-
creased because o decrease in the content of glucose
or maltotriose in the wort which is caused by inhibi-
tion of ~-amylase formation. Moreover, fermentability
is improved because of increase in the maltose content
in the wort, and the extract content is also increased
by the concomitant use of gibberellin.
It is known that the biosynthesis of ~-amylase in
the aleurone layer of barley is promoted by gibberellin
(especially GA3) but abscisic acid (hereinafter sometimes
referred to as ABA) hinders the biosynthesis ~Plant
Physiol. 42, 1008 (1967) and ~ature, 205, 1270 ~1965)].
It has also been made clear that the mechanism of
inhibition of the a amylase-biosyntheSis by ABA is not
due to the hindrance of m-P~NA induction of ~A~ but due
to the hindrance of translation of m-RNA into protein
~Cell, 20, 479 (198Q)]o In these reports, the effects
of ABA on the induction of m-RNA and formation of
~ amylasa were researched by adding GA3 and ABA in com-
bination to the endosparm or isolated aleurone layer of
barley.
These researches, however, do not ~each or suggest
~he manifestation of special effects achieved according
to the presen~ inven~ion, that is, by addition of both
GA3 and ABA to barley in a mcllting stage, (i) the yield
o malt, yield of extract ancl diastatic power can be
increased, and, moreover, (ii) the fermentability of
the resulting wort is improvad, and also the decomposi-
tion of proteins and the colc,r of wort can be controlledat will, and other effects~ In this connection,
general reports which teach that. the balance of certain
four plant hormones is required in the formation of
~-amylase are known [European Brewery Convention Proceed-
ings of the 14th Congress (Salzburg), p.757 (1973), (and
that of the 16th Congress (Amsterdam), P.63 (1977)]. The
special effects mentioned above, however, also could not
be anticipated from the above named reports.
The method of producing malt will now be described
in specific detail.1~ Maltin~ process
The present invention can be applied to conventional
malting processes. With reference to the present inven-
tion, the malting process is defined to comprise causing
grain for malt to absorb water and germinate.
The methods for pxoduction of malt which comprise
causing the grain to absorb w~ter and germinate are well
known in the art, and thus no description thereof in
detail will be needed hereinO If necessary, one can
refer to, for example, "Barley and Malt Biology, Bio-
chemistry, Teehnology, Ed. A.~. COOK, Academic Press,
1962, p.p. 271 -302." for the details of the malting
--5--
method. In addition to the essential stages of steeping and germination which
are closely related to the present invention, additional stages before, between
or after these two stages such as drying, removal of malt rootlets and other
treatment may be conducted.
The present invention can also be applied to the processes for produc-
tion of germinated products of other grain ~such as rice, beans and Indian corn),
other seeds, and starchy tubers such as various potatoes.
2. Abscisic compounds
.
Abscisic compounds which are abscisic acid and its Eunctional deriva-
tives are known plant hormones, the details of which are given in, for example,
ANNUAL REVIEW OF PLANT PHYSIOLOGY Vol. 25, p 259-307 (lg74) published by ANNUAL
REVIEWS INC. Palo Alto, California, U. S. A.
By the functional derivatives of abscisic acid are meant the deriva-
tives with respect to the carboxylic acid moiety of abscisic acid, especially
water-soluble salts and esters. Among the salts are included the salts thereof
which are allowable in view of food hygiene such as the alkali metal salts,
alkaline earth metal salts and ammonium salts thereof. Included among the
esters are the esters with lower alcohols and especially monohydric lower
alkanols having 1 to about 4 carbon atoms as well as the esters with sugars,
lower alkyl (Cl-C4) esters being preferable.
Other functional derivatives of abscisic acid to be used in the pre-
sent invention are the derivatives wi~h respect to the moieties other than the
carboxylic acid moiety. Such derivatives include, for example, xanthoxic acid,
hydroxyabscisic acid, phaseic acid, and dihydrophaseic acid. Moreover,
xanthoxins are other functional deriva~ives of abscisic acid which contain both
an aldehyde moiety instead of the carboxylic acid moiety and a 6-membered ring
substituent moiety. The acid and esters thereof can also be used in the present
invention.
` 1-
The amount of abscisic acid or a derivative thereof to be used in the
present invention is given below.
3. Gibberellic compounds
Gibberellic compounds which are gibberellin and its functional deriva-
tives, W]liC}I can be used in combina-tion with the abscisic compounds in accord-
ance with the present invention, are also lcnown plant hormones.
As the gibberellin are known a compo~md called GA3 as well as com-
pounds called GAl, GA4~ GA7 and GA9. It is also known that the gibberellin
used actually in malt-production industries consists essentially of a mixture of
these gibberellin compounds [J. Inst. Brew. ~0, 13-30 ~1974)]. The term
"gibberellin" used herein encompasses both any single compound ~e.g. GAl~and any
mixture thereof. The term "the functional
... ..
.,
derivatives" of gibberellin encompasses the saLts and
esters thereof, as described in the corresponding
paragraph for abscisic acid~
4~ Treatment o ra ~ malt
The abscisic compound is applied to grain for malt
either (i) in khe steeping process of the grain, viz.
when the grain is in the water~absorption stage~ that is,
in the period from the start of the step of contacting
the grain with water, ordinarily by steeping in water
or sprinkling with wa~er,to the point of ~ime just before
the grain begins to germinate with absorption of a
required amount of water, which may be about 37 to about
46% of water content in the grain, or (ii) in the
germination process, viz. when the grain is in ~he
germination stage, or in the stage of from the start to
the termination o~ genmination. In other words, the
abscisic compound is applied to grain from the stage of
starting the water-absorption by contacting the grain
with water to the stage of terminating the germination.
More specifically, the abscisic compound can be
_applied to the grain for malt, by dissolving the abscisic
compound in the water in which the grain is to be
steeped, or by sprinkling an aqueous solution of the
abscisic compound onto the grain and especially the
~5 grain which has absorbed water by steeping.
The quantity of the abscisic compound to be used
can be an optional value as long as it is reasonable.
More specifically, the quantity to be used is approxi-
mately ln the range of 0.001 to 100 ppm, preferably 0.01
to 10 ppm and ordinarily 0.1 to 1 ppm on the basis of
the weight of cereal grain (before steeping), in the case
of sprinkling the ~queous solution onto cereal grain which
has absorbed water by immersion. When the abscisic com-
pound is applied by other methods, the amount thereof to
be taken up in the cereal grain can be selected to fall
witbin the above~defined range.
The quantity of gibberellic compound, when it is
used in combination with the abscisic compound, can be
an optional value as long as it is reasonable. More speci-
fically, in the case of sprinkling an aqueous solution of
these compounds onto cereal grain which has absorbed water
through immersion, the quantity is approximately in the
range of 0~001 to 10 ppm and preferably 0.01 to 1 ppm on
the basis of the weight of the cereal grain (before water-
absorption~. When it is applied by other methods, the
quantity thereof to be taken up in the cereal grain can be
2Q selected to fall withîn the above described ran~e.
After application of the abscisic compound to the
grain for malt, it is necessary to keep the contact of
the abscisic compound ~-ith the grain until the effect of
the physiological activity of the abscisic compound on
the grain is exhibited as expected. Also in this respect,
it is preferclble to apply the abscisic compound to the
grain before the stage of germination~ When the abscisic
g_
compound is applied near the termination o. the germination
stage, it is necessary to allow the treated grain to stand
under the conditions or about 12 hours after the termina-
tion of the germination stage.,
5. Examples of Experiments
Example l
One (l) kg of malting barley (New Golden variety)
-rU~n~ in Yamanashi Prefecture, Japan~ was steeped in
water at 15C fox 6 hours and then drained for 6 hours.
This operation was repeated several times until the water
content of the barley reached 43%, and then the barley was
drained for 2 hours. An aqueous solution of abscisic acid
having a concentration of 1 x 10 3% or l x 10 2% (g/v) was
sprinkled onto the treated barley so that the quantity of
abscisic acid sprinkled corresponded to 0.1 or 1 mg. The
barley thus treated was subjected to germination for 6 full
days in an experimental malting apparatus and then was
dried in a kiln to produce malt. The analytical data of
the resulting malt are shown in Table l. In the suitable
range of abscisic acid concentrationsp the yield of malt
was increased in comparison with the control, the decomposi-
tion of proteins was inhibited, and the color of wort was
lowered. Thus, by the application of abscisic acid to the
process for production of barley malt in the case where
barley having a germination force strong enough to lower
the yield of malt or barley having protein-decomposition
power strong enough to deepen the color of wort is used,
the yield of malt can be increased~ and th~ decomposi-
tion of proteins and the color of wort can be controlled
at will.
Table 1
S
~ ... ..
Abscisic acid added
\Control ________~ _ *
\0.1 ppm 1 ppm
~ . ..
Yield of malt (d.m., %) 1 90.7 91.0 91.6
~ .. ___
Content of extract (d.mO, %)79.4 78.8 77.8
- ~ _ _
Formol nitrogen (mg/100 ml 29.6 28.0 22.2
_ A _ . _ _ _~, _ ~ _ _ __ __ ____ _ _ _ _ _ .
Kolbach Index (%) 47.6 44.2 37.1
.__ __ _ .
Color of wort (EBC unit) 4.7 4.4 3.4
... __ . ._ ...... __ . . _ _ ~ . _
Diastatic power (W.R.) 196 201 170
_ , ,.......... . ____ ~ _
ApparPnt attenuation lim.it 82.2 82.5 81.0
of wort (%)
~ _ .__.
Note: * mg/kg barley (as .is)
Example 2
.
As in Example 1, a mixture of abscisic acid and GA3
(O.1 mg per kg of barley) was sprinkled onto barley after
~5 steeping in water to prepare malt~ Analytical data of the
resulting malt are shown in Table 2O In the sui~abla range
of abscisic acid concentrations, the yield of malt and the
content o~ extract were increased, and the decomposi-
tion of proteins was satisfactorily controlled. Malt
of very good quality, wherein the conventional marked
increase in the color of wort caused by addition of
GA3 was innibited, was obtained. The malt had high
diastatic power and the apparent attenuation limit of
wort was normal.
Table 2
~ ,. ~ ,...... ~ . . . ,
Quantity of abscisic acid
adde~ (ppm*) 0 0 0.1
._ . .__ __ ,
Quanti-ty of GA3 added Q 0.1 0.1 O.1
. _ ~ ,. _ .
15Yield of malt (d.m.,~) 90.790.8 91.2 91.2
~ . . . . __ . .
Extract content (d.mO,~) 79.480.2 80.0 80.0
, __ ....... . ~ . . __ _ ,
Formol r~tr 29.6 33.5 31.8 25.4
. _ . . .
20Kolbach Index (~) 47.6 51.5 49.7 40.7
. . ~_.,.... - _ . __n
Color of wort (EBC unit) 4.7 6.9 5~3 4.1
__ _ ~ _
Diastatic power ( WoK~ ) 196 206 211 213
_ . ___ ._ n ~_ ~ _ . ___ ~ _ __ ____ _ _ .. __
Apparent attenuation 82.2 81.6 82.4 83.1
limit of wort ( % ) _ __ .
_ _ . _ .
Note: * mg/kg barley ~as is)
--12--
Example 3
As in Example 1, 0.1 ppm of GA3 was sprinkled onto
barley arter steeping in water (10 ml of an aqueous solution
of 1 x 10 3~ ~g/v) per kg of barley), and the barley thus
treated was subjected to germination for 24 hours in an
experimental malting apparatus. Then, abscisic acid was
sprinkled as described in Example 1 and the germination
operation was continued to produce malt. Analytical data
of the resulting malt are shown in Table 3. In the
suitable concentration range of abscisic acid, malt of a
very good quality was obtained as in Example ?, although
the effect of GA3 was observed to be stronger than ~hat
in the case of ~xample 2.
-13-
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- ~ - - - - - - -
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Example 4
Methyl abscisate and GA3 were sprinkled as in Example
7 onto malting barley (New Golden variety), which had been
s'f~e~
in water to have a water content of 42~ and then
drained for 2 hours in the same manner as in Example 1, to
produce malt. Analytical data of the resulting malt are
shown in Table 4. The effect of methyl abscisate was
cLearly exhibited. As in the case of abscisic acid
(Example 2), by the addition of a suitable quantity of
methyl abscisate, the quality of malt could be controlled
at will.
Tabl 4
. .. ~ ,, .
Quantity of methyl absci- 0 O
sate added (ppm*) 0.1
_ _ __ .. _ __ _
Quantlty of GA3 added 0 0.1 0.1 0.1
Yield of malt (d.m., ~) 91vl 9102 91.2 91.7
._ _ ~ _ __ . ,.
Extract content ¦ 79.1 79.9 79.8 79.0
~ . I _. - ___
Formol nitrogen ¦ 24.1 29.6 26.5 22.0
.~ ~ ~ _ _ __ ___
Kolbach Index (%) ¦44.849.0 47.0 41.5
~ ~ _ . _
Color of wort (EB~ unit) ¦ 3.1 ¦ 4.9 3.9 3.3
Diastatlc po~er (W.K.) ~ 229 227 232 211
~pparent attenuatlon limit¦ 83 o83.3 83.4 81.5
2S
Note: * mg/kg barley (as is)
-15-
Example 5
Abscisic acid and GA3 were sprinkled as in Example
2 onto malting barley (New Golden variety) which had been
steeped in water to have a water content of 41% and
then drained for 2 hours in t~e same manner as in Example
1. The barley thus treated w~as subjected to germination
in an experimental malting apparatus, sampled on the 3rd,
4th and 5th full day~, and dried in a kiln to produce
malt. Analytical data of the resulting m~lt are shown
in Table 5. When GA3 alone w~s used, the Kolbach Index
and color of wort were abnormally increased, although
tne period for germination collld be shortened by 1 or 2
days. On thé other hand, when a suitable concentration
range of abscisic acid was used iIl combination with GA3,
malt of good quality, in which the increase in the
Kolbach Index and the wort color was suitably controlled,
could be obtained in a higher yield in a shorter germina-
tion period in comparison with control samples.
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--17--
