JP2010193749A - Method for pretreatment of barley to be used for producing malt-fermented beverage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for the pretreatment of barley to be used for producing a malt-fermented beverage, by significantly decreasing nonenal potential in the malt-fermented beverage through effectively reducing LOX (lipoxygenase) activity in barley, resulting in enabling the flavor stability of the malt-fermented beverage to be improved. <P>SOLUTION: The method for the pretreatment of barley to be used for producing a malt-fermented beverage includes heating the barley with microwaves to reduce or deactivate the LOX activity in the barley. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pretreatment method for barley used in the production of a malt fermented beverage. More specifically, the present invention pretreats barley used for the production of a malt fermented beverage by heating it using a microwave in order to improve the flavor stability of the malt fermented beverage using barley as a part of the raw material. Regarding the method.

  Malt fermented beverages made from malt such as beer and sparkling liquor may accelerate the chemical reaction such as oxidation due to the passage of time, increase in temperature, etc., and the product may deteriorate. 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)

  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 the raw material in the malt fermented beverage, the present inventors preheated the raw barley in advance using a microwave in a predetermined condition before the saccharification step. Can effectively reduce LOX activity in barley, and can further significantly reduce the noneal potential (hereinafter sometimes referred to as “wort NP”) in wort obtained by saccharifying barley with malt. Successful. 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.
Therefore, it turned out that the flavor stability of the malt fermented drink which uses barley as a part of raw material can be improved by the pre-processing which heats the barley used for manufacture of the malt fermented drink using a microwave. The present invention is based on these findings.

  Therefore, the present invention effectively reduces the LOX activity in barley and greatly reduces the nonenal potential in the malt fermented beverage product, and as a result, improves the flavor stability of the malt fermented beverage, The object is to provide a pretreatment method for barley used in the production of beverages.

  The pretreatment method of barley used for production of a malt fermented beverage according to the present invention is characterized in that lipoxygenase (LOX) activity in barley is reduced or deactivated by heating the barley using microwaves.

  According to one preferable aspect of the present invention, in the pretreatment method, the heating condition using microwaves is at least in terms of thermal energy obtained by 1 g of water when barley is replaced with water of the same weight. This is a condition for applying thermal energy of 4.0 kcal.

  According to one more preferable aspect of the present invention, in the pretreatment method, the heating condition using microwaves is converted into heat energy obtained by 1 g of water when barley is replaced with water of the same weight, This is a condition for imparting thermal energy of 4.8 to 6.2 kcal.

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

  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 the present invention, since microwaves are used, unlike the case where barley is pretreated using hot water or water vapor, moisture is not used, so barley can be stored and stored again after pretreatment. . Also, the use of microwaves makes it easy to control the degree of processing and the processing time because the heat treatment can be easily stopped by stopping the microwave irradiation. For this reason, it is excellent in handling performance and can make it easier to control the quality of the pretreated barley. That is, according to this invention, the flavor stability in the malt fermented drink which uses barley as a part of raw material can be improved significantly. 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. At the same time, the method according to the present invention can cope with various manufacturing processes, and can further increase the manufacturing cost and the manufacturing efficiency.
Furthermore, the method according to the present invention can minimize the necessity of the barley scouring process, so that it can be said that this method is also excellent in cost.

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. FIG. 10 is a diagram showing the results of Example 3.

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 to reduce or deactivate lipoxygenase (LOX) activity in barley by heating the barley using microwaves. Features.

  Here, heating using microwaves typically means heating the target barley using a microwave heating apparatus. It is considered that the barley LOX contained in a large amount of the aleurone layer having a high water content in barley can be specifically deactivated or reduced in activity by applying the microwave treatment to the barley (this is a theory and the present The invention is not limited). The treated barley can be advantageously used in the brewing process.

  The microwave heating device that can be used here is a target by rotating or vibrating charged particles or electric dipoles in a target substance (barley in this case) under the influence of an oscillating electric field by microwaves. There is no particular limitation as long as the material can be heated and microwave heating can be performed. There is no restriction | limiting also in the frequency band of the microwave used, For example, it can be 2.45 GHz, 915 MHz, etc. In addition, the microwave heating device can be configured to be capable of continuous microwave irradiation heat treatment when it is desirable to continuously process as a manufacturing process, and when heated as a batch process, An industrial microwave heating device, a household microwave oven, or the like may be used. The conditions of the microwave heating apparatus can be mainly defined by the output value (for example, 0.3 kW to 300 kW) and the microwave irradiation time of the output value.

  After the heat treatment with microwaves, the pretreated barley can be cooled appropriately by allowing it to cool naturally or by placing it in a cold greenhouse or the like.

  The microwave heating condition is desirably a heating amount that reduces the LOX activity of barley to at least the LOX activity level that malt normally has, for example, a heating amount that reduces the LOX activity of barley by 50% or more. is there. Specifically, the heating condition is at least 4.0 kcal, preferably at least 4.1 kcal, more preferably at least about 4 in terms of thermal energy obtained by 1 g of water when barley is replaced with the same weight of water. It is a condition that imparts thermal energy of .8 kcal, more preferably about 4.8 to about 6.2 kca.

  It can be calculated and determined as follows, for example, that the heating condition by the microwave gives the heat energy in such a range. That is, when the heat treatment method is a batch type, a predetermined amount of water (100 ml of water when the container is a 100 ml beaker) is added to a container for heating barley (for example, a 100 ml beaker), and this is added for a predetermined time. Each heating time is determined from the difference between the water temperature before heating and the water temperature after heating by heating at a predetermined time interval using a microwave heating device to be used under a predetermined condition (for example, output value (W)). The temperature rise (° C.) is calculated, the thermal energy received when 1 g of water is heated for 1 second, and the value of the amount of thermal energy is obtained. In this way, in the microwave heating apparatus to be used, it is possible to determine what heat condition amount value is required by performing heat treatment under what setting conditions and for what time. More specifically, for example, it can be confirmed and obtained as shown in Example 4 described later.

  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 the main ingredients, and beverages obtained by adding additional alcohol components such as barley spirits to malt fermented alcoholic beverages (Including alcoholic beverages classified as “other miscellaneous sake 2” in the so-called liquor tax law).

  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 embodiment of the present invention, barley that has been refined and ground is used as the barley to be subjected to the pretreatment. As described above, since the LOX activity of barley is considered to be localized in the embryo part, it is possible to reduce the barley LOX activity by removing the barley surface by sperm. 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.

  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 ”).

  Each prepared 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 performed at a temperature of 50 ° C. for 60 minutes, and then subjected to conventional temperature and time passage 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 precolumn 2, and the eluate from the precolumn 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 (R ² = 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: Processing of barley microwave processed malt, which is the main ingredient of beer, is replaced with barley, and when a malt fermented beverage such as happoshu is produced, the flavor stability of the product deteriorates. One of the causes is considered to have higher LOX activity than malt. For this reason, in order to make the flavor stability of malt fermented beverages using barley as part of the raw material equivalent to or higher than that of barley-free beer, etc., the LOX activity of barley is made equal to or less than the LOX activity of malt. I thought it needed to be reduced. Therefore, the influence of microwave heating time on barley LOX activity was examined.

  First, 90g of milled barley (milling accuracy 90%) before pulverization is put in a 100mL beaker and placed in the center of a home microwave oven (ER-F3 manufactured by Toshiba Corporation), and the output is set to 500W. And heated for a predetermined time (60 seconds, 70 seconds, 80 seconds, 90 seconds, 110 seconds, and 130 seconds). Immediately after heating, the barley was spread on a stainless steel basket and allowed to cool naturally. The LOX activity of the barley obtained under each condition was measured according to the method described above.

  The results were as shown in Table 1.

From the results, by performing the microwave treatment for 70 seconds or more, the LOX activity of barley is from the average malt LOX activity (9.1 mg / L: average value of 27 malts produced in 2004, see FIGS. 1 and 2). Therefore, it was considered that the microwave heating time is preferably 70 seconds or more. On the other hand, it was found that when the microwave treatment was performed for 90 seconds or more, the barley LOX was completely deactivated.
From these, it was considered that the microwave heating time for barley is preferably 70 to 90 seconds.

Therefore, wort NP was also measured in order to confirm the effect of microwave heat treatment for 70 seconds, 80 seconds, and 90 seconds on the flavor stability of happoshu.
Wort was produced in the same manner as in Example 2 except that barley that had been subjected to microwave heat treatment for 70 seconds, 80 seconds, and 90 seconds was used.

  About each obtained wort, it carried out similarly to Example 2, and performed wort NP analysis. For comparison, wort NP when untreated barley was used was set to 100, and the obtained results were normalized.

  The results were as shown in Table 2.

From the results, when the microwave heat treatment time is 70 seconds, 80 seconds, and 90 seconds, the NP of the wort is 10%, 13%, and 24% compared to the case where untreated barley is used, respectively. %Diminished. From this, it was confirmed that when wort was produced using barley that had been subjected to microwave heat treatment to reduce barley LOX activity, it was beneficial to improve the flavor stability of the product.
Therefore, in order to dramatically improve the flavor stability of the product, it was considered that a microwave treatment time of 70 seconds to 90 seconds was desirable.

Example 4: Examination of microwave heating conditions (using a microwave heating device (microwave oven))
Performance evaluation of the microwave oven (Toshiba ER-F3, 500 W) used in Example 3 was performed, and the microwave heating time was converted into receptive heat energy, and generalization of heating conditions was examined.

  Specifically, 100 ml of water is added to a 100 ml beaker, and the microwave oven is set to a predetermined condition (output 500 W), and a predetermined time (20 seconds, 40 seconds, 60 seconds, 80 seconds, 100 seconds) Heating is performed, and the temperature rise (° C) for each heating time is calculated from the difference between the water temperature before heating and the water temperature after heating, and the thermal energy received when 1 g of water is heated for 1 second is calculated. did.

  The result was as shown in FIG.

From the results, it was found that there was a high correlation between the temperature rise temperature (° C.) and the microwave heating time (seconds). That is, as shown in the figure, the following correlation equation was obtained:
Temperature rise temperature (° C) = 0.687 × microwave heating time (seconds)

From this correlation equation, it was found that when 1 g of water was heated for 1 second using a microwave, the calories received by 1 g of water was 68.7 calories / second. That is, by applying microwave heat treatment, the calories received by 1 g of water is 4.1 kcal when treated in 60 seconds, 4.8 kcal when treated for 70 seconds, and 6.2 kcal when treated for 90 seconds. There was found.
Therefore, it was considered that the heat treatment conditions of 4.8 kcal (70 seconds) to 6.2 kcal (90 seconds) were preferable as the conditions for the microwave heat treatment in terms of thermal energy received by 1 g of water.

Claims (5)

  A method for pretreating barley used in the production of a malt fermented beverage, characterized in that lipoxygenase (LOX) activity in barley is reduced or deactivated by heating the barley using a microwave.   The heating condition using microwaves is a condition for applying thermal energy of at least 4.0 kcal in terms of thermal energy obtained by 1 g of water when barley is replaced with water of the same weight. The method described.   The heating condition using the microwave is a condition for applying thermal energy of 4.8 to 6.2 kcal in terms of thermal energy obtained by 1 g of water when barley is replaced with water of the same weight. Item 3. The method according to Item 1 or 2.   The method according to any one of claims 1 to 3, wherein barley that has been refined and ground 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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