JP2004321019A

JP2004321019A - Method for detecting malt inducing premature flocculation of yeast

Info

Publication number: JP2004321019A
Application number: JP2003116586A
Authority: JP
Inventors: Makiko Jibiki; 真紀子地引; Katsuya Sasaki; 克也佐々木
Original assignee: Asahi Breweries Ltd
Current assignee: Asahi Breweries Ltd
Priority date: 2003-04-22
Filing date: 2003-04-22
Publication date: 2004-11-18
Anticipated expiration: 2023-04-22
Also published as: JP4137687B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for accurately judging an ability to induce premature flocculation and settling of a yeast caused by malt in a much simpler manner in a much shorter period as compared with those of a conventional method. <P>SOLUTION: The method for judging the ability to induce the premature flocculation and settling of the yeast with the raw material malt is to judge the ability to induce the premature flocculation and settling of the yeast by the raw material malt according to a fermentation test using the yeast. The fermentation test for utilizing congress wort and adding a nutrient source thereto and/or setting the amount of dissolved oxygen at a rather high level and/or setting the fermentation temperature at a rather high level than the usual fermentation temperature is carried out to thereby promote proliferation of the yeast. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する利用分野】
本発明はビールや発泡酒あるいはウィスキー等の酒類醸造に用いる原料麦芽の酵母早期凝集沈降誘引能判定方法、すなわち原料麦芽の早期凝集因子の強弱判定に関する。
【０００２】
【従来の技術】
麦芽を原料として、酵母を用いて発酵により製造される酒類には、ビール、発泡酒やウィスキー等がある。
【０００３】
日本やドイツをはじめ世界各国でラガータイプのビールが醸造されているが、最近はアメリカを中心にライトタイプのビールの生産が、また日本では麦芽配合比率の低い発泡酒の生産量が増えてきている。これらのビールあるいは発泡酒の醸造には、発酵終了後に酵母が発酵タンクの底に沈降する下面酵母を用いることが多い。
【０００４】
このように原料として麦芽を使用する酒類を製造する場合に、発酵中に＜酵母の早期凝集沈降現象＞と呼ばれる現象が認められることがある。これは発酵終了前に酵母の資化可能な糖分がまだ麦汁中に残っているにもかかわらず、酵母が凝集・沈降してしまい、その結果発酵の進行が停止してしまう現象である。この事象が発生すると、発酵液中に糖やアミノ態窒素が残り、さらに、いわゆる未熟臭と呼ばれるようなＶＤＫ（ｖｉｃｉｎａｌｄｉｋｅｔｏｎｅ）や発酵不順臭といわれる麦汁臭アルデヒドが残り、ビールや発泡酒、あるいはウィスキー品質の著しい低下をもたらし、大きな損害を被ることが知られている。
【０００５】
この麦芽による酵母の早期凝集沈降現象は頻度高く生じる現象ではないが、一度早期凝集沈降を誘引する物質を含む麦芽を大量に工場に受け入れてしまうと、その処理が難しく、損害が大きくなる。
発酵中の酵母の早期凝集沈降現象を解明し、問題解決を図るベく研究が古くから進められてきた結果、原因の一つとして原料麦芽があげられ、主として麦芽の穀皮に含まれる高分子の酸性多糖類、あるいは糖鎖をもつレクチン様蛋白質が関与することが示唆されている。（非特許文献１、２）。しかし、この早期凝集沈降を誘引する原因となる因子（以下、ＰＹＦ（ＰｒｅｍａｔｕｒｅＹｅａｓｔＦｌｏｃｃｕｌａｔｉｏｎ）因子という）は麦の段階ですでに存在するとの報告（非特許文献３）や、浸麦工程など製麦工程中に生成するという報告（非特許文献４）もあり、原因物質の詳細やその生成機構は十分に明らかになっているとは言い難いのが現状である。
【０００６】
これまでの大麦を対照として、ＰＹＦ因子の存在の有無を調査する場合には、大麦を実際に小スケールで製麦して、その麦芽から実際に副原料を添加しない麦汁を調製した後、酵母を添加して発酵試験を行い、その進行状況から判断するという方法が報告されている（非特許文献２）。また、最近は大麦を酵素処理することによって得られた酵素処理物を発酵試験原料の一部または全部とし、２０℃で４８時間あるいは約８℃で８日間発酵試験を行い判断する方法が報告されている。（特許文献１）。しかしながら、この方法では製麦工程中にＰＹＦ因子が生成する場合には見落とす危険性がある。
【０００７】
一方、麦芽を対象として、ＰＹＦ因子の存在の有無を調査する場合には、その麦芽から実際に副原料を添加しない麦汁を調製した後、酵母を添加して約１週間あまりの発酵試験を行い、その進行状況から判断するという方法が報告されている（非特許文献２）。さらに麦芽穀皮からの水あるいは緩衝液抽出成分を酵母懸濁液に添加することで酵母の凝集・沈降を誘引する能力があるかどうかを判断するという簡便な方法も報告されているが、十分な精度は認められていない（非特許文献５）。
【０００８】
【特許文献１】
特許第３１２１５５２号公報
【非特許文献１】
Ｒｅｐｔ．Ｒｅｓ．Ｌａｂ．ＫｉｒｉｎＢｒｅｗｅｒｙＣｏ．，Ｌｔｄ．，１９，４５，１９７６
【非特許文献２】
Ｊ．Ｉｎｓｔ．Ｂｒｅｗ．，９７（５），３５９，１９９１
【非特許文献３】
Ｅｕｒ．Ｂｒｅｗ．Ｃｏｎｖ．Ｐｒｏｃ．５３−６０，１９９７
【非特許文献４】
ＭＢＡＡＴｅｃｈ．Ｑｕａｒｔ．，３７（４），５０１，２０００
【非特許文献５】
Ｐｒｏｃ．Ｅｕｒ．Ｂｒｅｗ．Ｃｏｎｖ．，Ｂｕｄａｐｅｓｔ，２００１，Ｎｏ．４２
【０００９】
【発明が解決しようとする課題】
本発明の課題は、上記従来方法に比べて、はるかに簡単かつ短期間で、精度良く麦芽に起因する酵母の早期凝集沈降性誘因能を判定する方法を提供することにある。
【００１０】
【課題を解決するための手段】
従来から麦芽の一般性状評価に幅広く用いられているコングレス麦汁を活用し、これに糖をはじめとする栄養源を添加し、溶存酸素量を高め、発酵温度を一般的な温度より高めに設定することにより、短期間に簡便で精度良く、麦芽に由来する酵母の早期凝集性を評価出来ることを見出し、本発明を完成した。また、本試験法は５０ｍｌの小スケールでも評価することが出来ることから、麦芽の一般性状を評価し終わった残りのコングレス麦汁を用いて試験を行うことが出来る。さらに、特殊な設備・装置を必要としないため、新たな試験法として導入することが容易である。
【００１１】
すなわち、本発明は、酵母を用いる発酵試験により原料麦芽による酵母の早期凝集沈降性誘引能を判定する方法において、コングレス麦汁を活用し、これに栄養源を添加しおよび／または溶存酸素量を高めに設定しおよび／または発酵温度を一般的な発酵温度より高めに設定する発酵試験を行うことにより、酵母の増殖を促進することを特徴とする原料麦芽の酵母早期凝集沈降性誘引能の判定方法を提供することである。
【００１２】
【発明の実施の形態】
本発明は、従来から麦芽の評価に幅広く用いられているコングレス麦汁（改訂ＢＣＯＪ分析法（財）日本醸造協会発行４．３コングレス麦汁、ＥｕｒｏｐｅａｎＢｒｅｗｅｒｙＣｏｎｖｅｎｔｉｏｎ．Ａｎａｌｙｔｉｃａ−ＥＢＣ（４^ｔｈｅｄ．），Ｍｅｔｈｏｄ４．４，ｐ．Ｅ５９．Ｂｒａｕｅｒｅｉ−ｕｎｄＧｅｔｒａｕｋｅ−Ｒｕｎｄｓｃｈａｕ，ＣＨ−８０４７．Ｚｕｒｉｃｈ，Ｓｗｉｔｚｅｒｌａｎｄ（１９８７））を活用する。これに糖をはじめとする栄養源を添加し、さらに十分な酸素を付与し、発酵温度を一般的な温度より高めに設定し、十分な通気を行い、酵母の増殖能を高めることにより、短期間に精度良く、麦芽に由来する酵母の早期凝集性を評価する方法を提供することが出来る。
【００１３】
以下に本発明を詳しく説明する。
【００１４】
試験用ＥＢＣコングレス麦汁を用意する。このコングレス麦汁は例えば、微粉砕した麦芽５０ｇに蒸留水２００ｍｌを加え４５℃で３０分保持後、２５分かけて１℃／分の割で７０℃に昇温させ、同温度の蒸留水１００ｍｌを加えて全体を４５０ｇとしてから一定規格の濾紙で濾過して得られたものを用いる。コングレス麦汁の量としては６０ｍｌ以上あれば試験が可能であるため、麦芽の量は１０ｇもあれば良いが、実験の精度を高めるためには、調査対象麦芽を代表するサンプルになるような分取量ならびに方法が望ましい。
【００１５】
また、評価の信頼性を向上させるために試験対照麦芽と比較することが好ましく、早期凝集沈降現象を生じない麦芽（ネガティブコントロール）と生じる麦芽（ポジティブコントロ―ル）から調製した麦汁もあわせて準備することが望ましい。さらに本試験法は５０ｍｌの小スケールでも評価が出来ることから、麦芽の一般性状を評価し終わった残りのコングレス麦汁を用いて試験を行うことが出来る。コングレス麦汁は微生物の汚染を受けやすいので、必要に応じてオートクレーブ処理を行うとよいが、下記に示すフィルター濾過までの一連の操作を連続して行うのであれば、行わなくても構わない。
【００１６】
続いて、一定量の栄養源を添加する。栄養源としては酵母の増殖が促進されるものが望ましく、糖、酵母エキスなどの発酵補助剤や微量ミネラルがあげられる。
【００１７】
糖を添加する場合において、添加濃度は添加後麦汁の糖濃度が、一般的な麦汁と同程度になれば良く、酵母の増殖が促進され、生育阻害の起こらない程度が望ましい。糖の種類は試験に用いる酵母が資化出来るものならいずれでも良いが、酵母による代謝スピードを考えると、麦汁中に含まれるグルコースなどの単糖類や、マルトースなどの二糖類が望ましい。また、その他の栄養源も酵母の増殖が促進され、生育阻害の起こらない添加量が好ましい。
【００１８】
栄養源を添加したコングレス麦汁は、０．４５μｍのフィルター濾過を行うことにより、環境中の微生物を取り除くことが望ましい。
【００１９】
続いて、麦汁中の酸素濃度を飽和させるために通気を行う。通気の方法は無菌的な空気の吹込みや酸素の吹込みなど、一般的な方法で良いが、低温下で十分に麦汁を攪拌することによっても、容易に十分な濃度の酸素量を付与させることが可能である。
【００２０】
十分量の酸素を取り込ませた麦汁を発酵試験用の減菌済み容器に移す。容器は直径に対して深さが十分にある円筒形のものが好ましく、例えばメスシリンダーなどが至適な形状であり、安価かつ容易に入手することができる。スケールは５０ｍｌ以上なら判断が可能である。
【００２１】
発酵に用いる酵母の種類は、試験の信頼性をあげ、得られたデータの有効性を高めるためには、実際にビールや発泡酒の製造に用いている種類が最も好ましいが、凝集性を持つ一般的な下面酵母でも良い。
【００２２】
酵母の添加量は十分な増殖がおこり、発酵が行なわれる量ならいくらでも良いが、試験期間を短縮し、明確な試験結果を得るためには初発酵母が１〜２×１０^７ｃｅ１１ｓ／ｍ１程度になるように添加することが好ましい。
【００２３】
発酵温度は下面酵母の増殖に適した温度ならいずれでも良い。試験に用いる酵母の種類によっても最適温度は多少異なるが、試験期間を短縮し、酵母を十分に増殖させるためには、発酵温度を１０〜２５℃とするのが好ましく、さらに１５〜２０℃が好ましい。
【００２４】
発酵中の酵母の生育度合いおよび浮遊酵母数の変化は、―般的な酵母数の測定装置や濁度計あるいは分光光度計で６００〜８００ｎｍ程度の波長を用いて経時的に測定すればよい。
【００２５】
なお、酵母数を測定するための試料は発酵液表面から一定の深さのところからサンプリングすることが望ましい。発酵後期の浮遊酵母数を、対照である酵母の早期凝集沈降現象を生じない麦芽と生じる麦芽から調製した麦汁の試験と比較することにより、試験対象麦芽に酵母の早期凝集沈降性を誘引する性質があるかどうかを判断することが出来る。
【００２６】
さらに、酵母が早期に凝集沈降すると上記でも述べたように、麦汁中の栄養分の取り込みが抑制されることから、発酵後期の麦汁中の糖濃度を測定することによっても早期凝集沈降性を評価することが出来る。なお、糖濃度は密度によって測る方法やＨＰＬＣを使う方法など一般的な方法で良い。
【００２７】
【発明の効果】
本発明により原料麦芽に由来する酵母の早期凝集沈降性を、麦汁から最短２日以内で正確に再現性高く判定することが可能になる。さらに、コングレス麦汁を用い、特殊な設備、装置を用いないことから既存の試験に追加して実施することが容易である。
【００２８】
【実施例】
以下に実施例を用いて本発明を具体的に説明するが、本発明はこれに限定されるものではない。
【００２９】
常法に従って調製したコングレス麦汁を１１５℃、１０分間オートクレーブ処理を行い、熱トルーブを析出させた後に、遠心分離処理を行って熱トルーブを除去する。続いて、遠心後のコングレス麦汁６０ｍｌを分取して、グルコースを２．４ｇ添加し十分に溶解する。０．４５μｍのフィルターで除菌して試験麦汁の調製を終了する。
【００３０】
続いて、ビール工場で発酵後に回収した酵母を初発酵母数が１．５×１０^７ｃｅ１１ｓ／ｍ１になるように植菌し、１５℃にて４８時間発酵させる。発酵開始２４時間程度経過したところで酵母数を測定し、発酵が順調に進行していることを確認する。なお、酵母数を測定するための試料は常に発酵液表面から４ｃｍの深さのところからサンプリングする。続いて発酵開始４０時間経過したところで再び酵母数を測定する。麦芽に酵母の早期凝集沈降を誘引する性質がある、すなわちＰＹＦ因子がある場合は、この時点で浮遊酵母数が著しく低下していることを確認出来る。さらに、発酵を継続し、発酵開始４８時間で酵母数および麦汁中に残っている糖濃度を測定する。麦芽に酵母の早期凝集沈降を誘引する性質がある場合は、酵母数だけではなく、発酵後期の麦汁中の糖濃度にも差異が認められ、早期凝集沈降が生じる麦芽では糖が多く残ることが確認出来る。
【００３１】
酵母の早期凝集沈降現象を生じない麦芽と生じる麦芽を用いて３０００Ｌスケールで実際のビール醸造を行った時と、上記の本発明の発酵試験を行った時の浮遊酵母数の経過を図１、図２に示す。ビール醸造において、酵母の早期凝集・沈降性が認められた麦芽は本試験法によってより一層明らかな酵母の凝集沈降を認めることができ、短期間に容易に麦芽の酵母の早期凝集沈降性誘引能を評価することが可能であった。さらに醸造の発酵開始後７日目と本試験の発酵４８時間後における麦芽中に残る糖濃度（ショ糖換算）を表１に示すが、糖濃度についてもビール醸造と本試験の間に関係性があることを確認した。
【００３２】
【表１】

【図面の簡単な説明】
【図１】酵母の早期凝集沈降現象を生じない麦芽（１）と生じる麦芽（２）を用いて３０００Ｌスケールでビール醸造を行った時の浮遊酵母数の変化を示す図である。
【図２】酵母の早期凝集沈降現象を生じない麦芽（１）と生じる麦芽（２）を用いて本発明の方法で５０ｍｌスケールの発酵試験を行った時の浮遊酵母数の変化を示す図である。[0001]
FIELD OF THE INVENTION
The present invention relates to a method for judging the ability of a raw material malt to be used for brewing alcoholic beverages such as beer, low-malt beer, whiskey, etc., in order to induce early flocculation and sedimentation of yeast, that is, to determine the level of early flocculation factor of raw malt.
[0002]
[Prior art]
Liquors produced by fermentation using malt as a raw material using yeast include beer, low-malt beer, whiskey and the like.
[0003]
Lager-type beers are brewed in countries around the world, including Japan and Germany. Recently, light-type beers have been produced mainly in the United States, and in Japan, the production of low-malt beer with a low malt blending ratio has increased. I have. For brewing such beer or low-malt beer, a bottom yeast in which yeast settles to the bottom of a fermentation tank after fermentation is completed is often used.
[0004]
As described above, when producing alcoholic beverages using malt as a raw material, a phenomenon called <early flocculation and sedimentation of yeast> may be observed during fermentation. This is a phenomenon in which the yeast agglomerates and sediments even though the assimilable sugar content of the yeast still remains in the wort before the fermentation ends, and as a result, the progress of the fermentation is stopped. When this event occurs, sugars and amino nitrogen remain in the fermentation liquor, and wok odor aldehydes called VDK (vicinal diketone) and unfermented fermentation, which are so-called immature odors, remain, and beer, happoshu, Alternatively, it is known to cause a significant decrease in whiskey quality and cause severe damage.
[0005]
The early flocculation and sedimentation of yeast due to malt is not a phenomenon that occurs frequently, but once malt containing a substance that induces early flocculation and sedimentation is received in a factory in large quantities, its treatment is difficult and the damage is increased.
Studies have been conducted for a long time to elucidate the early flocculation and sedimentation phenomenon of yeast during fermentation, and as a result of this research, raw malt has been raised as one of the causes, and macromolecules mainly contained in the malt husk It has been suggested that an acidic polysaccharide or a lectin-like protein having a sugar chain is involved. (Non-Patent Documents 1 and 2). However, factors that induce this early coagulation and sedimentation (hereinafter referred to as PYF (Premature Yeast Flocculation) factors) have already been reported at the wheat stage (Non-Patent Document 3), There is also a report (Non-Patent Document 4) that it is formed during the process, and it is difficult to say that the details of the causative substance and the mechanism of its formation have been sufficiently clarified.
[0006]
When barley is used as a control to investigate the presence or absence of the PYF factor, barley is actually malted on a small scale, and wort that does not actually include an auxiliary material is prepared from the malt, A method of performing a fermentation test by adding yeast and judging from the progress thereof has been reported (Non-Patent Document 2). Recently, a method has been reported in which an enzyme-treated product obtained by enzymatically treating barley is used as a part or the whole of a fermentation test raw material and a fermentation test is performed at 20 ° C. for 48 hours or at about 8 ° C. for 8 days to make a judgment. ing. (Patent Document 1). However, in this method, if PYF factors are generated during the malting process, there is a risk of overlooking them.
[0007]
On the other hand, when investigating the presence or absence of a PYF factor in malt, a fermentation test for about one week after adding malt to the malt without preparing an auxiliary material from the malt is performed. A method has been reported in which the determination is made based on the progress (Non-Patent Document 2). Further, a simple method of determining whether or not there is an ability to induce yeast flocculation / sedimentation by adding water or a buffer extract component from malt husk to a yeast suspension has been reported. High accuracy has not been recognized (Non-Patent Document 5).
[0008]
[Patent Document 1]
Japanese Patent No. 3121552 [Non-Patent Document 1]
Rept. Res. Lab. Kirin Brewery Co. , Ltd. , 19, 45, 1976
[Non-patent document 2]
J. Inst. Brew. , 97 (5), 359, 1991.
[Non-Patent Document 3]
Eur. Brew. Conv. Proc. 53-60, 1997
[Non-patent document 4]
MBAA Tech. Quart. , 37 (4), 501, 2000
[Non-Patent Document 5]
Proc. Eur. Brew. Conv. , Budapest, 2001, no. 42
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for accurately and quickly determining the ability of yeast to induce early flocculation and sedimentation due to malt, in a much simpler and shorter time than the above-mentioned conventional method.
[0010]
[Means for Solving the Problems]
Utilizes congress wort, which has been widely used for evaluating the general properties of malt, adds sugars and other nutrients, increases the amount of dissolved oxygen, and sets the fermentation temperature higher than the general temperature. By doing so, the present inventors have found that early flocculation of yeast derived from malt can be evaluated simply and accurately in a short period of time, and completed the present invention. In addition, since this test method can be evaluated even on a small scale of 50 ml, the test can be performed using the remaining congress wort after the evaluation of the general properties of malt. Further, since special equipment and devices are not required, it is easy to introduce a new test method.
[0011]
That is, the present invention provides a method for determining the ability of a raw material malt to induce early coagulation and sedimentation of yeast by a fermentation test using yeast, utilizing congress wort, adding a nutrient source to the wort, and / or measuring the amount of dissolved oxygen. A fermentation test in which the fermentation temperature is set higher and / or the fermentation temperature is set higher than a general fermentation temperature is used to promote the growth of yeast. Is to provide a way.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is widely used is to have Congress wort in the evaluation of malt from the conventional (revised BCOJ spectrometry (Foundation) Japan Brewing Society issued 4.3 Congress ^{wort, European Brewery Convention.Analytica-EBC (4} th ed.) U.S.A., Method 4.4, p.E59. Brauerei-und Getrauke-Rundschau, CH-8047. Zurich, Switzerland (1987)). Add nutrients such as sugar to this, add enough oxygen, set the fermentation temperature higher than the general temperature, perform sufficient aeration, and increase the growth ability of yeast, It is possible to provide a method for accurately evaluating the early flocculation property of malt-derived yeast in between.
[0013]
Hereinafter, the present invention will be described in detail.
[0014]
Prepare a test EBC congress wort. For example, this congress wort is prepared by adding 200 ml of distilled water to 50 g of finely ground malt, keeping the mixture at 45 ° C. for 30 minutes, and then raising the temperature to 70 ° C. at a rate of 1 ° C./minute over 25 minutes, and adding 100 ml of distilled water at the same temperature. Is added to make the whole 450 g, and then a filter obtained by filtering through a filter paper of a certain standard is used. Since the test is possible if the amount of congress wort is 60 ml or more, the amount of malt may be as much as 10 g. However, in order to improve the accuracy of the experiment, a sample that is representative of the malt to be investigated is used. The yield and method are desirable.
[0015]
In order to improve the reliability of the evaluation, it is preferable to compare the malt with the test control malt, and the wort prepared from the malt that does not cause the early flocculation phenomenon (negative control) and the malt that generates the malt (positive control) is also included. It is desirable to prepare. Further, since this test method can be evaluated even on a small scale of 50 ml, the test can be performed using the remaining congress wort after the general properties of the malt have been evaluated. Since the congress wort is susceptible to microbial contamination, it may be subjected to an autoclave treatment as necessary. However, if a series of operations up to the filtration by a filter shown below are continuously performed, it may be omitted.
[0016]
Subsequently, a certain amount of nutrient is added. As a nutrient source, one that promotes the growth of yeast is desirable, and examples thereof include fermentation aids such as sugar and yeast extract and trace minerals.
[0017]
In the case of adding sugar, the concentration of the added wort may be such that the sugar concentration of the wort after the addition is almost the same as that of general wort, and it is desirable that the growth of yeast is promoted and the growth is not inhibited. Any kind of sugar can be used as long as the yeast used in the test can assimilate, but in view of the metabolic speed by the yeast, monosaccharides such as glucose contained in wort and disaccharides such as maltose are desirable. Further, other nutrients are preferably added in such a manner that the growth of yeast is promoted and growth is not inhibited.
[0018]
It is desirable that the congress wort to which the nutrient source is added is filtered through a 0.45 μm filter to remove microorganisms in the environment.
[0019]
Subsequently, ventilation is performed to saturate the oxygen concentration in the wort. The ventilation method may be a general method such as aseptic air blowing or oxygen blowing, but it is also possible to easily provide a sufficient concentration of oxygen by sufficiently stirring the wort at a low temperature. It is possible to do.
[0020]
The wort having sufficient oxygen incorporated therein is transferred to a sterilized container for a fermentation test. It is preferable that the container has a cylindrical shape having a sufficient depth with respect to the diameter. For example, a graduated cylinder or the like has an optimal shape, and can be easily obtained at low cost. Judgment is possible if the scale is 50 ml or more.
[0021]
The type of yeast used for fermentation is most preferably the type actually used in the production of beer or low-malt beer in order to increase the reliability of the test and increase the validity of the obtained data, but it has cohesiveness General bottom yeast may be used.
[0022]
The amount of yeast to be added is not particularly limited as long as sufficient growth occurs and fermentation is performed. However, in order to shorten the test period and obtain clear test results, the initial yeast is reduced to about 1 to 2 × 10 ⁷ ce11s / m1. It is preferable to add them in such a way that
[0023]
The fermentation temperature may be any temperature suitable for the growth of bottom yeast. The optimum temperature varies somewhat depending on the type of yeast used in the test, but in order to shorten the test period and allow the yeast to grow sufficiently, the fermentation temperature is preferably 10 to 25 ° C, and more preferably 15 to 20 ° C. preferable.
[0024]
Changes in the degree of growth of yeast and the number of suspended yeast during fermentation may be measured over time using a general yeast number measuring device, turbidimeter, or spectrophotometer using a wavelength of about 600 to 800 nm.
[0025]
It is desirable that a sample for measuring the number of yeast be sampled from a certain depth from the surface of the fermented liquid. Induce the early flocculation and sedimentation of yeast in the test malt by comparing the number of floating yeast in the late stage of fermentation with the test of malt that does not cause the early flocculation phenomenon of the control yeast and the wort prepared from the malt that occurs. You can judge whether there is a property.
[0026]
Furthermore, as described above, when the yeast flocculates and sediments early, the uptake of nutrients in the wort is suppressed, so that the early flocculation and sedimentation properties are also measured by measuring the sugar concentration in the wort at the later stage of fermentation. Can be evaluated. The sugar concentration may be determined by a general method such as a method of measuring the density or a method of using HPLC.
[0027]
【The invention's effect】
According to the present invention, the early flocculation and sedimentation of yeast derived from raw malt can be accurately and highly reproducibly determined within 2 days from wort. Further, since congress wort is used and no special equipment or device is used, it is easy to carry out the test in addition to the existing test.
[0028]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.
[0029]
The congress wort prepared according to a conventional method is subjected to an autoclave treatment at 115 ° C. for 10 minutes to precipitate a hot tube, and then a centrifugal separation process is performed to remove the hot tube. Subsequently, 60 ml of the congress wort after centrifugation is collected, and 2.4 g of glucose is added and sufficiently dissolved. The bacteria are removed with a 0.45 μm filter to complete the preparation of the test wort.
[0030]
Subsequently, the yeast collected after fermentation at the beer factory is inoculated so that the initial yeast number is 1.5 × 10 ⁷ ce11 s / ml, and fermented at 15 ° C. for 48 hours. At about 24 hours after the start of fermentation, the number of yeasts is measured to confirm that the fermentation is proceeding smoothly. In addition, the sample for measuring the number of yeasts is always sampled from a depth of 4 cm from the surface of the fermented liquid. Subsequently, after 40 hours from the start of fermentation, the number of yeasts is measured again. If malt has the property of inducing early flocculation and sedimentation of yeast, that is, if there is a PYF factor, it can be confirmed at this point that the number of suspended yeast has significantly decreased. Further, the fermentation is continued, and the number of yeasts and the concentration of sugar remaining in the wort are measured 48 hours after the start of fermentation. When malt has the property of inducing early flocculation and sedimentation of yeast, not only the number of yeasts but also the sugar concentration in the wort at the later stage of fermentation shows a difference. Can be confirmed.
[0031]
FIG. 1 shows the progress of the number of floating yeasts when actual beer brewing was performed on a 3000 L scale using malt and malt that did not cause early flocculation and sedimentation of yeast, and when the above-described fermentation test of the present invention was performed. As shown in FIG. Malt in which early flocculation and sedimentation of yeast was observed in beer brewing can be more clearly observed by this test method, and the ability to induce the early flocculation and sedimentation of malt yeast easily in a short period of time. Was able to be evaluated. Further, Table 1 shows the sugar concentration (in terms of sucrose) remaining in the malt 7 days after the start of fermentation in brewing and 48 hours after fermentation in this test. The relationship between sugar concentration and beer brewing is also shown in Table 1. Confirmed that there is.
[0032]
[Table 1]

[Brief description of the drawings]
FIG. 1 is a diagram showing a change in the number of floating yeasts when beer brewing is performed on a 3000 L scale using malt (1) and malt (2) that do not cause early flocculation and sedimentation of yeast.
FIG. 2 is a diagram showing a change in the number of floating yeasts when a 50-ml scale fermentation test is performed by the method of the present invention using malt (1) and malt (2) that do not cause early flocculation and sedimentation of yeast. is there.

Claims

In a method for determining the ability of a raw malt to induce early flocculation and sedimentation of yeast by a fermentation test using yeast, the ability of the raw malt to induce early flocculation and sedimentation of yeast using a nutrient-added wort is used. Judgment method.

The method according to claim 1, wherein a congres wort to which sugar is added as a nutrient source is used.

The method according to claim 2, wherein the saccharide is a monosaccharide or a disaccharide.

The method according to claim 1, 2 or 3, wherein a congress wort to which oxygen is sufficiently added is used.

5. The method according to claim 1, 2, 3 or 4, wherein the fermentation temperature is set higher than that of ordinary beer or low-malt beer, and congress wort is used, so that yeast of the raw malt is agglomerated early. A method for determining sedimentary attraction.

The method according to claim 2, wherein the fermentation temperature is 10 to 25C.

The method according to claim 1, 2, 3, 4, 5, or 6, wherein the early flocculation and sedimentation of the yeast is determined by measuring the number of floating yeasts in the fermentation broth or the turbidity of the fermentation broth after a fixed time. A method for judging the ability of a raw material malt to induce early flocculation and sedimentation of yeast.

The method according to claim 1, 2, 3, 4, 5, 6, or 7, wherein the early aggregation and sedimentation of yeast is determined by measuring the sugar concentration in the fermented liquid after a certain period of time. A method for judging the ability of malt yeast to coagulate and sediment at an early stage.