JP5260153B2 - A pretreatment method for barley used in the manufacture of malt fermented beverages - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for pretreating barley used for producing a malt-fermented drink, by which LOX activity in the barley is effectively reduced to greatly lower nonenal potential in the malt-fermented drink product and simultaneously prevent the lowering of an amino acid concentration in the barley, consequently improving the flavor stability of the malt-fermented drink. <P>SOLUTION: Provided is the method for pretreating the barley used for producing the malt-fermented drink, characterized by contacting the barley with steam for 30 to 120 min. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

Background of the Invention

FIELD OF THE INVENTION The present invention relates to a pretreatment method for barley used in the manufacture of malt fermented beverages. More specifically, the present invention relates to a method for pretreating barley used for the production of a malt fermented beverage using steam in order to improve the flavor stability of the malt fermented beverage using barley as a part thereof.

Background Art Malted fermented beverages made from malt such as beer and sparkling liquor may be deteriorated in product due to accelerated chemical reactions such as oxidation due to the passage of time and temperature. In a deteriorated product, the original taste and aroma (ie, flavor) of the beverage are impaired, resulting in a decrease in quality. Among them, “cardboard odor” (also referred to as cardboard odor) is a representative example of such a deteriorated odor, and it is possible to suppress the generation of this cardboard odor and improve the flavor stability of malt fermented beverages. This is one of the most important beverage manufacturing technologies. Aldehydes, particularly trans-2-nonenal (hereinafter sometimes referred to as “T2N”) are known as the main causative substances of cardboard odor.

  Trans-2-nonenal is derived from lipoxygenase (hereinafter sometimes referred to as “LOX”) in which linoleic acid contained in the raw material (usually malt) or a lipid containing linoleic acid in the side chain is also contained in the raw material. It is considered that a precursor (hydroxide derivative) of trans-2-nonenal is formed through enzymatic oxidation or auto-oxidation, and trans-2-nonenal is produced through oxidative degradation. For this reason, in order to improve the flavor stability of a product, it is important to suppress T2N generated in the product. To date, a method for producing raw malt having low LOX activity (JP 2005-102690 A) (Patent Document 1)), results of studies on the effect of LOX activity on flavor stability (N. Kobayashi et al, Proceeding of the EBC, 1993, p405- (Non-Patent Document 1), International Publication WO 01/85899 ( Patent document 2) has been reported.

  In addition, the document BW Drost et al., Am. Soc. Brew. Chem. Journal, Vol. 48, No. 4, pp. 124-131 (1990) (Non-patent Document 2) includes wort lipoxygenase (LOX). ) And the amount of nonenal potential and the amount of trans-2-nonenal in naturally degraded product beer are highly correlated, and these values are useful for predicting the potential for product degradation in beer products. It has been reported. Here, the amount of nonenal potential (NP) is the total amount of trans-2-nonenal and its precursor contained in wort or the like, and the amount of trans-2-nonenal that is potentially contained in wort or the like. I mean.

  It has been studied so far to suppress the amount of T2N in a product by reducing or deactivating LOX activity in raw malt.

  For example, International Publication WO2007 / 072780 (Patent Document 3) discloses that enzyme activity including LOX in malt is reduced by bringing raw material malt into contact with water vapor. Japanese Patent Application Laid-Open No. 2008-017759 (Patent Document 4) discloses reducing the LOX activity in malt by heating the raw material malt to 40 ° C. or higher after wetting.

  However, all of these studies and reports were directed to LOX activity contained in malt, which is the main raw material.

  In recent years, in addition to malt, fermented malt beverages using various cereals (for example, barley) and sugars as a part of raw materials are becoming widespread. As such a beverage, for example, a low malt fermented beverage (for example, happoshu) in which the amount of raw malt used is reduced is known. As far as the present inventors know, few studies have been reported on the effects of raw materials other than malt used in such fermented malt beverages on the flavor stability of products.

Such raw materials other than malt naturally have properties different from those of malt, and are intended to impart a taste and deliciousness to a malt fermented beverage using only malt. For this reason, it is not necessarily appropriate to apply the method of suppressing the amount of T2N in products, which has been studied in conventional products, to the case of malt fermented beverages using raw materials other than malt as they are.
Therefore, it has been desired to develop an appropriate technique that can reduce the “cardboard odor” that can occur in such a malt fermented beverage and improve the flavor stability of the beverage.

JP 2005-102690 A International Publication WO2001 / 85899 International Publication WO2007 / 072780 JP 2008-017759 A N. Kobayashi et al, Proceeding of the EBC, 1993, p405- B. W. Drost et al., Am. Soc. Brew. Chem. Journal, Vol. 48, No. 4, pp. 124-131 (1990)

Summary of the Invention

  Since the present inventors are a raw material for malt and are themselves used as a secondary raw material other than malt, they have focused on barley among cereals and conducted various studies. First, the LOX activity of barley was examined. As shown in Example 1 of Examples described later, all the LOX activities of various lots of barley harvested in 2004 in various countries including Canada, Europe and Australia and all malts produced using these barleys The barley LOX activity was found to be at least 4 times (approximately 5 to 7 times) stronger than the malt LOX activity, although there was some variation depending on the barley production area. . That is, since the LOX activity of barley is remarkably higher than that of malt, it has now been found that the effect of barley LOX activity on the flavor stability of a malt fermented beverage using barley as a part thereof is extremely large.

  Since it can be expected that the LOX activity of barley is localized in the embryo part, it is conceivable to remove or reduce the barley LOX activity by removing the barley surface by grinding (also referred to as “peeling”). However, considering large-scale production in factories and the like, production costs are expected to be high, which is not an effective method. A method of selecting and using a barley variety having low LOX activity is also conceivable, but it cannot be said to be a realistic method in consideration of time and cost for breeding a barley variety having such a desired trait.

  In the case of using barley as a part of raw material in a malt fermented beverage, the present inventors pre-treated the raw barley with steam before the saccharification step under predetermined conditions, thereby reducing LOX in the barley. The activity can be effectively reduced, and furthermore, the nonenal potential (hereinafter sometimes referred to as “wort NP”) in wort obtained by saccharifying barley with malt has been successfully reduced. In addition, as in the case of beer made from wort obtained by saccharifying only malt, the wort prepared by mixing barley and malt is also between the LOX activity of barley (and malt) and wort NP. It was also confirmed that there was a positive good correlation. For this reason, it was found that wort NP of wort prepared by mixing barley and malt can also be a good indicator of the amount of T2N generated in the product, that is, a deteriorated odor generated.

  On the other hand, when barley is used as a part of the raw material, it is expected that the flavor and taste will be further added to the malt fermented beverage product by the protein and amino acid components contained in the barley. These effects may be lost or diminished. In addition, if the amino acid in the wort containing amino acids derived from barley is insufficient, it is expected that in the subsequent yeast fermentation process, the metabolism of the yeast will be insufficient, which may ultimately cause abnormal flavor due to insufficient disappearance of diacetyl. The In particular, when the use ratio of malt which is an amino acid supply source is small, it is considered necessary to pay sufficient attention to the amino acid concentration in wort.

  For this reason, the present inventors also measured the influence on the amino acid concentration in the wort by the pretreatment of barley, and when performing the pretreatment under the above-mentioned predetermined conditions, the reduction of the amino acid concentration can be suppressed. However, in cases other than the above predetermined conditions, a decrease in amino acid concentration was observed.

  Therefore, by pretreating barley according to the above-mentioned predetermined conditions, LOX activity in barley was effectively reduced, and at the same time, it was unexpectedly successful in suppressing the decrease in amino acid concentration. The present invention is based on these findings.

  Therefore, the present invention effectively reduces LOX activity in barley and significantly reduces the nonenal potential in malt fermented beverage products, and at the same time, suppresses the decrease in amino acid concentration in barley. As a result, It is an object of the present invention to provide a pretreatment method for barley used for producing a malt fermented beverage, which improves flavor stability.

  The pretreatment method of barley used for production of a malt fermented beverage according to the present invention is characterized in that barley is brought into contact with water vapor for 30 to 120 seconds.

  According to one preferable aspect of the present invention, in the pretreatment method, the water vapor is saturated water vapor.

  According to another preferred embodiment of the present invention, in the pretreatment method, the water vapor is saturated water vapor at a normal pressure of 100 ° C.

  According to a further preferred aspect of the present invention, refined barley is used for pretreatment in the pretreatment method.

  According to another aspect of the present invention, there is provided a method for producing a malt fermented beverage characterized by using pretreated barley obtained by the pretreatment method according to the present invention and malt as raw materials.

According to the pretreatment method for barley of the present invention, the LOX activity contained in barley can be reduced, and the wort nonal potential and product T2N in a malt fermented beverage using barley as a part of the raw material can be significantly reduced. As a result, it is possible to remarkably improve the flavor stability of the malt fermented beverage while suppressing the generation of a deteriorated odor. In particular, since the LOX activity of barley is significantly higher than that of normal malt, the present invention can improve the flavor stability of beverages using barley as a part of the raw material very effectively. In addition, since the decrease in the amino acid concentration of the wort can be suppressed, it is possible to avoid abnormal flavor in the fermentation process, and further improve the taste and deliciousness of the malt fermented beverage with amino acids derived from barley. Can do. That is, according to this invention, the flavor stability in the malt fermented drink which uses barley for a part can be improved. This can be said to mean that it does not affect the product quality other than the process and flavor stability of the malt fermented beverage to which the pretreatment method according to the present invention is applied.
Further, the method according to the present invention can be said to be an excellent method in terms of cost because it can minimize the necessity of the barley scouring process.

  On the other hand, in the pretreatment method according to the present invention, since raw barley is pretreated with steam, the operation is relatively simple, and a large amount of barley can be easily pretreated at low cost.

Detailed description of the invention

  As described above, the pretreatment method of barley used for producing a malt fermented beverage according to the present invention is characterized by contacting barley with water vapor for 30 to 120 seconds, preferably with water vapor for 40 to 120 seconds. By setting the contact time to 30 seconds or longer, the LOX activity contained in barley can be reduced to a desired level, and wort NP and product T2N can be greatly reduced. Moreover, the fall of the amino acid density | concentration of wort can be suppressed by making contact time within 120 second, and it can avoid that flavor abnormality is raise | generated in a product.

In the present invention, the pretreatment with water vapor is carried out under normal pressure using an open container, not a closed container. Here, it is preferable to use saturated steam at 100 ° C. as the steam. At this time, the gauge pressure of the piping for supplying water vapor is 0.1 to 0.3 MPa, preferably 0.2 to 0.3 MPa.
In the present invention, it is desirable to perform steam treatment using an open-type vessel. However, by appropriately changing the treatment time and the like so that the same treatment as the pretreatment conditions according to the present invention is possible, normal pressure saturation is achieved. Superheated steam may be used instead of steam.

  For the pretreatment with water vapor of the present invention, for example, a steam treatment device is prepared that includes a known steam boiler that can freely generate water vapor having a predetermined temperature and pressure, and a heat-resistant reaction vessel that can withstand high-temperature water vapor. However, this may be implemented here. In such a processing apparatus, the water vapor | steam produced | generated by the steam boiler can be introduce | transduced in the reaction container which accommodated the barley which should be processed, and it can be comprised so that water vapor | steam can contact barley. Such a reaction vessel may be a batch type or a continuous type such as a rotary valve type or an extruder type.

The pretreatment with water vapor of the present invention is carried out, for example, by placing barley in a commercially available steaming machine (for example, manufactured by Fujiwara Techno Art Co., Ltd.) and the above treatment (for example, a predetermined time with steam having a gauge pressure of 0.2 MPa) under predetermined conditions. The heat treatment can be carried out. The barley after the steam treatment may be placed in a commercially available cooler (for example, manufactured by Fujiwara Techno Art Co.) as needed, and allowed to cool until the barley surface temperature falls to room temperature.
Examples of container types that can be used in the pretreatment with water vapor according to the present invention include a steaming machine, a steamer, and a sterilizer.

  In the present invention, “malt fermented beverage” refers to a beverage obtained by fermenting a raw material mainly composed of added hop wort obtained using malt as a raw material, such as beer, sparkling liquor, Further examples include liqueurs obtained by adding alcohol to beer or sparkling liquor. Furthermore, in the present invention, “malt fermented beverage” is used in the sense of including a malt fermented beverage using barley as part of the raw material (for example, as an auxiliary material).

  In the present invention, a “beer-like beverage” that does not use malt as a raw material is a beverage that can generate a deterioration odor due to trans-2-nonenal, that is, trans-2-nonenal or a precursor thereof, in the same manner as malt fermented beverages. Can be understood as being able to be handled in the same manner as the “malt fermented beverage”. In other words, even in the production of a “beer-like beverage” that does not use malt as a raw material, the beverage can generate a deterioration odor due to trans-2-nonenal, and barley is used as part of the raw material. For example, the pretreatment method of barley according to the present invention can be applied. Examples of such “beer-like beverages” include barley as a part of the raw material, and, for example, fermented beverages having the same or similar flavor as beer and mainly made of grains. , Beverages obtained by fermenting beans-derived components such as soybeans and peas and hops as main ingredients (including alcoholic beverages classified as “other miscellaneous sake 2” under the liquor tax law) It is done.

  In the present invention, “wort” is not particularly limited as long as it can be understood by those skilled in the art as wort, for example, wort obtained in the production process of a malt fermented beverage such as beer or happoshu. In general, the process for producing a malt fermented beverage such as beer is a malting process in which malt is prepared, and the malt is saccharified in a saccharification tank and then filtered to obtain filtered wort. It includes a preparation process for obtaining finished wort. Specifically, wort includes wort obtained in these steps (total filtered wort) or wort further prepared therefrom. In the present invention, “wort” is used to mean wort prepared by mixing barley and malt when barley is used as part of the raw material.

  Specifically, for example, in the present invention, wort is a mixture obtained by pre-treating barley and then mixing the barley and malt prepared from the malting process in a predetermined ratio in hot water at about 50 ° C. (This is called mash) and the temperature of the obtained mash is raised from 50 ° C. to 80 ° C. over a predetermined time, saccharified, and filtered to separate solids to obtain wort . In this invention, after adjusting this wort sugar degree to 12 degree P, it attach | subjects to the measurement of the following NP and can measure wort NP.

In the present invention, the “nonenal potential” (NP) amount refers to the amount of trans-2-nonenal and its precursor contained in beverages and wort, and is a realistic and potentially contained trans in a test sample. It is an index that means the total amount of -2-nonenal. Further, the nonenal potential can be an index for knowing a potential deterioration odor. In the calculation of the amount of the nonenal potential, for example, the literature BW Drost et al., Am. Soc. Brew. Chem. Journal, Vol. 48, No. 4, pp. 124-131 (1990) (Non-Patent Document 2) Although the item of nonenal potential may be referred to, in the present invention, it can be carried out according to WO2001 / 85899 (Patent Document 2). Specifically, a certain amount (1/5 amount of the buffer) of the test sample was added to the acetate buffer adjusted to pH 4.0, and this was heated (boiled) at 100 ° C. for 2 hours to produce. By measuring the amount of trans-2-nonenal, the amount of nonenal potential of the test sample can be obtained.
In addition, although the amount of NP in the total filtered wort in which the sugar content of the wort is adjusted to 11 ° P (plateau) varies depending on the type of beer, it is usually about 7 to 10 ppb.

  In the present invention, T2N (trans-2-nonenal) can be measured according to the method of Verhagen et al. (L. C. Verhagen et al, Journal of Chromatography, 1987, 393, page.85-). Specifically, T2N in a sample is subjected to solid phase extraction, and dansyl hydrazine is added to form a T2N-dansyl hydrazine derivative. The amount of T2N can be measured by separating the T2N-dansylhydrazine derivative by HPLC using the column switching method and measuring the amount of T2N-dansylhydrazine derivative using the absorbance at 252 nm. Here, the sample is wort or a product, and the product used is a product that has been forcedly deteriorated by standing at 37 ° C. for 7 days in a state of being filled in a container.

  In the present invention, when it is necessary to measure the wort extract concentration, the concentration should be measured, for example, according to the section “7.2 Extract” of “Beer Analysis Method” (edited by the Brewery Association). Can do. That is, the specific gravity of wort is measured, and the wort extract concentration can be calculated from the specific gravity extract conversion table.

  According to a further preferred aspect of the present invention, refined barley is used as barley to be subjected to pretreatment. As described above, since the LOX activity of barley is considered to be localized in the embryo part thereof, the barley LOX activity can be reduced by removing the barley surface by semen. That is, barley samples having various LOX activities can be prepared by changing the degree of mashing barley, that is, the accuracy of mashing. In the present invention, when the barley to be used is scoured in advance, the level of scouring to be performed can be appropriately set in consideration of an increase in production cost due to scouring, work efficiency of production, and the like. In the present invention, the wrinkle accuracy can be set to 90%, for example.

  Here, the barley milling can be adjusted to the milling accuracy by putting it into a commercially available grinding-type rice mill (eg, TM050 manufactured by Satake Co., Ltd.) and adjusting the grinding time. The degree of milling can be expressed as milling accuracy, and the milling accuracy is obtained as a value obtained by dividing the weight of barley after milling by the introduced barley. Accordingly, the longer the grinding processing time, the more precise the grinding, and the smaller the grinding accuracy.

  In the present invention, the barley to be pretreated can be pulverized if necessary. By pulverizing, the heat treatment in hot water can be performed more efficiently. The pulverization can be performed using a commercially available disc mill (for example, a gap of 0.2 mm).

  In the present invention, the lipoxygenase (LOX) activity in barley or malt can be measured, for example, as follows. First, a barley or malt pulverized product extracted with an acetate buffer solution (pH 5.0) containing sodium chloride is used as an enzyme solution, and a suspension of linoleic acid in a borate buffer solution (pH 9.0) is used as a substrate. Both are mixed in a phosphate buffer (pH 6.8) and the absorbance at 234 nm is measured. Since the conversion product of linoleic acid due to LOX activity has absorption specific to 234 nm, the amount of increase in absorbance over a predetermined time is determined as LOX activity.

  In this invention, the measurement of the amino acid concentration of wort can be analyzed according to a conventional method using, for example, a commercially available fully automatic amino acid analyzer (for example, L-8800 manufactured by Hitachi High-Technologies Corporation). In the present invention, it is desirable that the decrease in the amino acid concentration of wort is as small as possible due to the influence of the pretreatment according to the present invention. Specifically, the control sample of the present invention is compared with the control sample not subjected to the pretreatment of the present invention. It is desirable that the fluctuation of the amino acid concentration of the wort when the pretreatment is performed is maintained within about 10%, for example.

  As described above, the malt fermented beverage according to the present invention can be obtained according to a conventional method for producing a fermented malt beverage using the pretreated barley obtained by the pretreatment method according to the present invention and malt as raw materials. . Specifically, for example, the pretreated barley obtained by the pretreatment method according to the present invention and malt are mixed in hot water (for example, water at about 50 ° C.), and the temperature is raised according to a predetermined temperature course. After saccharification and filtration to obtain wort, hop is added here and boiled, it is subjected to a fermentation process by yeast, further filtered through a predetermined storage period, filled into a container, A desired malt fermented beverage (for example, happoshu) can be produced.

  In this specification, the expression of a value using “about” and “degree” includes a variation in a value that can be allowed by those skilled in the art to achieve the purpose by setting the value. Meaning.

  The present invention will be described in detail by the following examples, but the present invention is not limited thereto.

Example 1: Comparison of lots of barley and malt LOX activity In 2004, a total of 27 barley (27 lots) harvested in Canada, Europe and Australia were prepared and obtained from malt manufacturers in these regions. A total of 24 points (24 lots) were prepared. Specifically, the breakdown of barley is 2 varieties of Canada (analysis score 3), 7 varieties of Europe (analysis score 15), 8 varieties of Australia (analysis score 9), and the breakdown of malt is from Canada 6 The score was 6 from Europe and 12 from Australia.

The LOX activity of each lot of barley was measured by the following procedure.
First, each lot of barley was pulverized with a disk mill (0.2 mm gap), weighed 5 g, and suspended in 40 ml of 50 mM acetate buffer (pH 5.0) containing 0.1 M sodium chloride cooled on ice. This was placed in a cold room (10 ° C. or lower), stirred gently for 1 hour with a stirrer, and the supernatant obtained by centrifugation was used as a crude enzyme solution.

  On the other hand, linoleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) is suspended in a 25 mM borate buffer solution (pH 9.0) containing 0.25% Tween 20 to a final concentration of 0.25% together with sodium hydroxide. , Dissolved. The resulting solution was used as a substrate solution.

In advance, 2.85 mL of 100 mM phosphate buffer (pH 6.8) and 100 μL of the substrate solution were mixed and kept at 25 ° C., and 50 μL of the crude enzyme solution was added. “Sometimes referred to as“ A234 ”) was measured for 3 minutes.
The LOX activity is defined as 1 unit (hereinafter referred to as “U”) that increases A234 by 1 per minute, and the enzyme amount divided by barley dry matter weight (hereinafter referred to as “U / g ”).

  Malt was carried out in the same manner as in the case of barley described above.

  The results were as shown in FIG. 1 and FIG.

  Comparing the amount of enzyme per gram of barley or malt, the barley LOX activity was about 50 to 70 U / g, whereas the malt LOX activity was about 10 U / g. That is, barley had a strong LOX activity about 5 to 7 times that of malt.

Example 2: Effect of barley LOX activity on flavor stability of malt fermented beverages using barley as a part of the raw material It is considered that barley LOX activity is localized in the embryo part, and barley LOX activity is removed when the barley surface is removed by mashing or We thought it could be reduced. Thus, one lot of barley was obtained with three types of different milling accuracy (75, 85, and 92.5%), and each of these milled barley was disc milled (0.2 mm gap). After pulverization, LOX activity was measured for each milled barley. As a result, the LOX activity was 14.8, 19.4, and 27.4 U / g in order from the one with the lowest wrinkle accuracy.

Next, saccharification was performed using malted barley and malt having different LOX activities.
That is, 120 mL of water was put into a saccharified beaker, the water temperature was kept at 50 ° C., 40 g of crushed barley barley and 40 g of malt were added simultaneously, and the mixture was stirred well to be uniform. The saccharification was carried out at a temperature of 50 ° C. for 60 minutes, and then subjected to conventional conditions of temperature and time well known to those skilled in the art. The obtained saccharified solution was well stirred and filtered using filter paper (Toyo Filter Paper No. 2), and the collected filtrate was obtained as wort. The wort sugar content of the obtained wort was adjusted to 12 ° P by hydration, and this was used for the measurement of wort NP.

  For the analysis of wort NP, 10 mL of wort and 40 mL of 200 mM acetate buffer (pH 4.0) were mixed, and T2N was generated by heat treatment at 100 ° C. for 2 hours. 10 mL of this solution was applied to a Sep-Pak C18 cartridge (manufactured by Waters) and eluted with 1 mL of methanol. An acetic acid solution and a dansyl hydrazine (manufactured by SIGMA) solution were added to a part of the methanol eluate to form derivatization, and then introduced into HPLC using a column switching method to analyze T2N.

The HPLC configuration was as follows:
Pre-column 1 and 2 (for concentration): Shim-Pack SPC-PR3 (30 mm × 4.0 mm, 9 μm),
Column 1 (for preparative): YMC-Pack ProC18 (150 mm × 4.6 mm, 5 μm, manufactured by YMC),
Column 2 (for separation): YMC-Pack (250 mm × 4.6 mm, 5 μm, manufactured by YMC),
-Detector: UV detector.

The mobile phase was as follows:
Mobile phase 1: methanol-0.1 M acetate buffer (pH 4.0) (50:50, v / v),
Mobile phase 2: methanol-0.1 M acetate buffer (pH 4.0) (20:80, v / v),
Mobile phase 3: 0.1 M acetate buffer (pH 4.0),
-Mobile phase 4: Acetonitrile-0.1M acetate buffer (pH 4.0) (70:30, v / v).

  In HPLC, all flow rates were 1 mL / min.

Analysis by HPLC was performed as follows.
That is, a T2N dansyl hydrazine derivative was injected into the HPLC and supplied to the precolumn 1 together with the mobile phase 1. At this stage, the T2N dansyl hydrazine derivative is adsorbed on the precolumn 1. Next, the mobile phase 2 was switched to the column 1 while eluting the T2N dansyl hydrazine derivative from the precolumn 1. The mobile phase 3 having an equal flow rate (1 mL / min) was injected into the outlet of the column 1 using another pump, and introduced into the pre-column 3 while reducing the methanol concentration. Next, the mobile phase 3 was injected into the pre-column 2 to wash away methanol and others. At this stage, the T2N dansyl hydrazine derivative is selectively adsorbed on the precolumn 2. Next, the mobile phase 4 was switched, the mobile phase 4 was injected into the pre-column 2, and the eluate from the pre-column 2 was directly introduced into the column 2.
The column 2 eluate was guided to a UV detector, and the absorbance at 252 nm was measured. Using a calibration curve prepared in advance using a T2N standard product (manufactured by Tokyo Chemical Industry), the T2N concentration of the sample was calculated from the magnitude of the 252 nm absorbance of the sample to obtain wort NP.

  The result was as shown in FIG.

  As shown in the figure, it was found that there was a positive good correlation (R2 = 0.953) between barley LOX activity and wort NP. Since the malts used for the preparation of the three types of wort were the same, it was considered that the change in wort NP was dependent on the difference in barley LOX activity. In addition, it was considered that by reducing the LOX activity of barley, it is possible to ultimately reduce T2N produced in the product, that is, improve the flavor stability of the product.

Example 3: Steaming barley (measurement of barley LOX activity)
After putting 3 kg of unpolished barley before pulverization into a steaming machine (manufactured by Fujiwara Techno Art Co., Ltd.), heat treatment was performed for a predetermined time with steam having a gauge pressure of 0.2 MPa. The barley after the steam treatment was placed in a cooler (manufactured by Fujiwara Techno Art) and allowed to cool until the barley surface temperature dropped to room temperature.
Barley LOX was measured as described above for samples at each treatment time.

  The results were as shown in Table 1 below.

As shown in the results, when the steam treatment is performed for 30 seconds, the LOX activity of barley is higher than the average malt LOX activity (9.1 U / g (average value of 23 lots of 2004 malt, see Example 1)). It turned out to be lower. When part of the malt, which is the main ingredient of beer, is replaced with barley and a malt fermented beverage such as happoshu is produced, the flavor stability of the product deteriorates because barley has a higher LOX activity than malt. It is thought to be the cause. Therefore, in order to make the flavor stability of malt fermented beverages using barley as part of the raw material equal to or higher than that of barley-free beer, the LOX activity of barley is equal to or lower than the LOX activity of malt. It is thought that it is necessary to do. For this reason, it was considered that the steam treatment time is desirably 30 seconds or longer.
On the other hand, it was also found that the barley LOX activity was completely inactivated when the steam treatment was performed for 120 seconds.

Example 4: Steaming barley (measurement of wort NP and wort amino acid concentration)
Based on the results of Example 3, for the case where the steaming time of barley is in the range of 30 to 120 seconds, the effect of the steaming on the flavor stability and quality of a malt fermented beverage such as happoshu is examined. Therefore, wort NP and wort amino acid concentrations were measured for wort obtained using steam-treated barley.

First, wort NP concentration which is a freshness index was examined. Specifically, wort obtained according to the following method was produced.
That is, after the steamed barley was treated with steam, it was pulverized using a disk mill (0.2 mm gap). Subsequently, 120 mL of water was put into a saccharification beaker, and the water temperature was maintained at 50 ° C. Here, 40 g of the pulverized pearl milled barley and 40 g of the pulverized malt were added at the same time, and stirred well so as to be uniform. The saccharification was carried out at a temperature of 50 ° C. for 60 minutes, and then subjected to conventional conditions of temperature and time well known to those skilled in the art. The obtained saccharified solution was well stirred and filtered using filter paper (Toyo Filter Paper No. 2), and the collected filtrate was obtained as wort. The wort obtained was adjusted to a wort sugar content of 12 ° P by hydration and used for analysis of wort NP / amino acid.
As a control, wort was obtained in the same manner as the steam except that untreated milled barley was used.
NP of the obtained wort was measured according to the method described above.
From the measurement results, relative values were calculated with wort NP as 100 when untreated barley was used.

  The results were as shown in Table 2 below.

  When the steam treatment time was 40 seconds or more, the NP was almost constant, and was reduced by about 30% compared to the case where untreated barley was used. Thus, it turned out that the very high wort NP reduction effect is acquired by performing steam processing to barley.

Next, the wort amino acid concentration that greatly affects the product quality was measured. The amino acid concentration of wort was measured according to a conventional method using an automatic amino acid analyzer (L-8800 manufactured by Hitachi High-Technologies Corporation).
From the measurement results, the amino acid concentration of the wort in each case was determined, and a relative value with the amino acid concentration of the control wort as 100% was calculated for each case.

  The results were as shown in Table 3 below.

  It was found that when the steam treatment time was 30 seconds to 120 seconds, the wort amino acid concentration was in the range of 90% to 100% compared to the control. If the amino acid concentration was reduced by 10% or less, it was considered that the quality of the malt fermented beverage was not greatly affected.

FIG. 6 is a diagram showing the results of Example 1. FIG. 6 is a diagram showing the results of Example 1. FIG. 6 is a diagram showing the results of Example 2.

Claims (5)

A method for pretreating barley used for the production of a malt fermented beverage, characterized in that barley is brought into contact with saturated steam for 30 to 120 seconds. The method of claim 1, wherein the water vapor is saturated water vapor at normal pressure .   The method according to claim 1, wherein the water vapor is saturated water vapor at 100 ° C. and normal pressure.   The method according to any one of claims 1 to 3, wherein the refined barley is used for pretreatment.   The manufacturing method of the malt fermented drink characterized by using the pre-processed barley obtained by the pre-processing method as described in any one of Claims 1-4, and malt as a raw material.

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