JP4787605B2 - Yeast fermentation method - Google Patents

Description

  The present invention relates to a yeast fermentation method, and more particularly to a yeast fermentation method suitable for evaluation of raw materials and yeast.

  Examples of liquors produced by fermentation using malt as a raw material include yeast, beer, happoshu and whiskey.

  Lager type beers are brewed in Japan, Germany and other countries around the world. Recently, light type beer production has been increasing mainly in the United States, and in Japan, the production of Happoshu with a low malt blending ratio has increased. Yes. In brewing these beers or happoshu, bottom yeast, in which the yeast settles at the bottom of the fermentation tank after the completion of fermentation, is often used.

  Thus, when producing alcoholic beverages using malt as a raw material, a phenomenon called <early coagulation sedimentation phenomenon of yeast> may be observed during fermentation. This is a phenomenon in which the yeast agglomerates and settles, and as a result, the progress of the fermentation stops, even though the sugar that can be assimilated by the yeast still remains in the wort before the end of the fermentation. When this event occurs, sugar and amino nitrogen remain in the fermented liquid, and further, VDK (vicinal diketone) called so-called immature odor and wort odor aldehyde called unsaturated fermentation remain, and beer, sparkling liquor, Alternatively, it is known to cause a significant loss of whiskey quality and suffer significant damage.

  Although the early agglomeration and sedimentation phenomenon of yeast due to malt is not a phenomenon that occurs frequently, once a large amount of malt containing a substance that induces early agglomeration and sedimentation is received in a factory, the processing is difficult and the damage is increased.

  Research on elucidating the early aggregation and sedimentation phenomenon of yeast during fermentation and research to solve the problem has long been promoted, and one of the causes is the raw material malt, which is mainly a polymer contained in malt husk It has been suggested that lectin-like proteins having acidic polysaccharides or sugar chains are involved. However, it is reported that a factor that induces this early aggregation and sedimentation (hereinafter referred to as PYF (Premature Yeast Fluctuation) factor) already exists in the wheat stage, and that it is generated during the wheat making process such as the soaking process. There are reports, and it is difficult to say that the details of the causative substances and the mechanism of their production have been sufficiently clarified.

  Therefore, barley is actually made on a small scale, and after preparing wort that does not actually add auxiliary materials from the malt, a fermentation test is performed by adding yeast, and the method of judging from its progress is a method. Has been done. One example of this is the use of congested wort, which has been widely used for the evaluation of the general properties of malt, adding nutrients such as sugar to it, increasing the dissolved oxygen content, and making the fermentation temperature higher than the general temperature. There has been proposed a method for evaluating the early aggregability of yeast derived from malt by setting it higher (Patent Document 1).

  However, in this method, there is a problem that the operation becomes complicated because it requires the addition of nutrient sources, the treatment for increasing the amount of dissolved oxygen, and the temperature control for setting the fermentation temperature higher than the general temperature. Furthermore, since fermentation conditions are different from usual, fermentation may not be stable and lack reproducibility.

  In addition, the evaluation of cohesiveness is important not only for the evaluation of raw materials but also for the determination of superiority or inferiority of bottom fermentation yeast. This is because, in beer production, yeast is precipitated and separated in the late stage of fermentation using the cohesiveness of the bottom fermenting yeast, and yeast that is not agglomerated and remains floating even in the late stage of fermentation is removed from the beer. Therefore, operations such as centrifugation are required. Therefore, it is necessary to select a strain having an agglomeration property of appropriate strength or weak strength.

On the other hand, in a large volume culture of 0.5 to 200000 liters, it is known that by adding zeolite, the culture efficiency is improved by the adsorption of carbon dioxide and the like (Non-patent Document 1).
Japanese Patent Laid-Open No. 2004-321919 Biotechnology Letters, Vol9, No9, 640-642 (1987)

  The problem to be solved by the present invention is to sufficiently and stably ferment yeast without performing complicated operations in small-volume stationary fermentation.

  Moreover, it is evaluating the influence which it has on the cohesiveness of yeast or a raw material with high precision and reproducibility using small-volume stationary fermentation.

The method of the present invention for solving the above problems is as follows.
(1) A method for fermenting yeast, comprising adding yeast and a dissolved carbon dioxide-reducing substance to a culture solution to allow stationary fermentation to be performed.
(2) The method for fermenting yeast according to (1), wherein the fermentation is performed in a small volume of 50 ml or less.
(3) The yeast fermentation method according to (2), wherein fermentation is performed in a photometric cell.
(4) The yeast fermentation method according to (1), wherein the dissolved carbon dioxide-reducing substance is a porous substance.

  By adding yeast and dissolved carbon dioxide-reducing substances to the culture medium and allowing them to perform static fermentation, the fermentation proceeds sufficiently even with small volumes, and it is possible to easily evaluate yeast under conditions close to actual production. Become.

  By performing fermentation in a small volume container of 50 ml or less, it is possible to easily evaluate a large number of yeasts in a small space.

  By performing fermentation in the photometric cell, it can be easily set in a spectrophotometer after the fermentation is completed. Moreover, it becomes possible to measure a fermentation state continuously by making it ferment in the photometric measurement cell set to the spectrophotometer.

  By using a porous substance as the dissolved carbon dioxide reducing substance, the dissolved carbon dioxide can be efficiently reduced, and the fermentation can sufficiently proceed even in a small-volume stationary fermentation.

  The dissolved carbon dioxide-reducing substance in the present invention is a substance that adsorbs dissolved carbon dioxide or promotes the release of dissolved carbon dioxide, and is preferably porous zeolite (zeolite).

  Dissolved carbon dioxide reducing substances can be effective with very little addition.

  Yeast was added to 1 ml of wort prepared using barley without early agglomeration, and 1 ml of wort, yeast and zeolite (zeolite) as a dissolved carbon dioxide reducing substance were added to another test tube. Static fermentation was performed at 21 ° C. for 2 days, and the number of yeasts after 40 hours was measured.

  Similarly, 1 ml of wort adjusted with barley with high early flocculation and yeast is added to one test tube, and 1 ml of wort adjusted with barley with high early flocculation, yeast and dissolved dioxide are added to another test tube. Zeolites (zeolites) were added as carbon reducing substances. Static fermentation was performed at 21 ° C. for 2 days, and the number of yeasts after 40 hours was measured.

As shown in Fig. 1, the number of yeast in the test tube containing only wort and yeast without early flocculation was 0.342 × 10 ⁶ , while yeast and dissolved carbon dioxide were reduced in wort without early flocculation. The number of yeast in the test tube to which the substance was added was 34.2 × 10 ⁶ . Similarly, the number of yeasts in the test tube with only early aggregating wort and yeast was 0.416 × 10 ⁶ , whereas yeast and dissolved carbon dioxide reducing substances were added to the wort with early early aggregating ability. The number of yeast in the test tube was 6.31 × 10 ⁶ .

  It was confirmed that the addition of a dissolved carbon dioxide-reducing substance significantly improved the fermentation state regardless of the presence or absence of early aggregation and increased the number of yeasts.

  Add 50 ml of distilled water to 50 g of malt that is finely ground barley without early cohesion, hold it at 45 ° C. for 30 minutes, raise the temperature to 70 ° C. at a rate of 1 ° C./minute over 25 minutes, and then add 100 ml of distilled water at the same temperature. The whole is made to 450 g and then filtered through a filter paper of a certain standard, and then concrete wort is subjected to autoclaving at 115 ° C. for 10 minutes to precipitate a hot-trove, and then subjected to a centrifugal separation to remove the hot-trove. Remove. Subsequently, 60 ml of the congested wort after centrifugation is collected, and 2.4 g of glucose is added and sufficiently dissolved. The test wort is finished by sterilizing with a 0.45 μm filter (hereinafter referred to as N wort). N-wort and barley having early cohesiveness were similarly mixed with wort (hereinafter referred to as “P wort”) prepared in the same manner to produce six types of wort having different early coagulant properties. Three test tubes were prepared by adding bottom fermentation yeast (hereinafter referred to as yeast) and zeolite to 3 ml of wort for 6 types of wort. Static fermentation was performed at 21 ° C. for 2 days, and the number of yeasts after 41.5 hours was measured. The results are shown in Table 1 and FIG. In FIG. 2, the three bar graphs of each ratio indicate samples 1, 2, and 3, respectively, from the left.

  It was proved that the early aggregability was remarkably evaluated with good reproducibility because the difference in early agglomeration was noticeable and there was little deviation between samples under the same conditions.

  50ml N wort with yeast added, 50ml P wort with yeast added, 50ml N wort with yeast and dissolved carbon dioxide reducing substance (stirrer), 50ml N wort What added yeast and the dissolved carbon dioxide reduction substance (stirrer) to soup was created. Static fermentation was performed at 21 ° C. for 2 days, and the change over time in the number of yeasts was measured. The results are shown in Table 2 and FIG.

  When the dissolved carbon dioxide reducing substance (stirrer) is added, the difference in the number of yeasts in each wort is large, and the tendency of each wort can be clearly grasped.

  What added yeast and dissolved carbon dioxide reducing substance (zeolite) to 3 ml N wort in the measuring cell of spectrophotometer, and yeast and dissolved carbon dioxide reducing substance (zeolite) added to 3 ml P wort It was created. Static fermentation was performed at 21 ° C. for 2 days, and the change in absorbance was continuously measured. The results are shown in Table 3 and FIG.

  In the case of P wort having a high early aggregability, the absorbance begins to decrease in about 20 hours, and it can be confirmed that the agglomeration starts early.

  In this example, only the early aggregation property was evaluated. However, since the difference in aggregation property becomes remarkable due to good fermentation, the present invention is also effective in evaluating the aggregation property of yeast. It is not limited to sex evaluation.

  According to the present invention, fermentation can proceed sufficiently even if the same stationary fermentation as in production is performed in a small volume, and the fermentation state based on raw materials and yeast can be evaluated easily and accurately with good reproducibility in a small volume. Is possible.

The figure which shows the difference of the number of yeast after fermentation with the dissolved carbon dioxide reduction substance Figure showing the difference in the number of yeast after fermentation due to early aggregation The figure which shows the change of the number of yeast with fermentation time The figure which shows the time-dependent change of the yeast number in the cell for optical measurement

Claims (4)

  A method for fermenting yeast characterized by adding a yeast and a dissolved carbon dioxide-reducing substance to a culture solution to cause stationary fermentation.   2. The yeast fermentation method according to claim 1, wherein the fermentation is performed in a small volume of 50 ml or less.   The yeast fermentation method according to claim 2, wherein fermentation is performed in a photometric cell.   The yeast fermentation method according to claim 1, wherein the dissolved carbon dioxide reducing substance is a porous substance.

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