JP2019033737A - Bread yeast produced by hybridization between saccharomyces bayanus and saccharomyces cerevisiae - Google Patents

Abstract

To provide bread yeast for practical use enabling bread production with superior flavor and form as well as methods for bread production using such yeast.SOLUTION: By hybridizing Saccharomyces bayanus B9 L3 and Saccharomyces cerevisiae H24U1M, a bread yeast for practical use that enables production of bread with superior flavor and form is obtained. By using such a yeast in bread making, bread with excellent flavor and form can be produced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to baker's yeast and the like. Specifically, a yeast for bakery produced by crossing a strain belonging to Saccharomyces bayanus and a strain belonging to Saccharomyces cerevisiae, which can produce bread having a better flavor and shape, and a bread using the yeast It relates to a manufacturing method and the like.

  In the bread-making process, the bread-making yeast expands the dough with carbon dioxide gas that is generated when the sugar contained in the dough is converted to ethanol. It gives a flavor. Since such yeast products available for breadmaking have been selected based on the traits of bread dough fermentation at 20 to 30 ° C., almost all strains are classified as Saccharomyces cerevisiae.

  Saccharomyces cerevisiae, which has a strong ethanol fermentation ability, is widely used in many industries. However, as described above, the activity in this temperature range is used for bread making where fermentation is performed at 20-30 ° C. Limited to high Saccharomyces cerevisiae. However, from such selection criteria and the like, those traits are relatively uniform, and there is a limit in obtaining a baker's yeast having unprecedented characteristics.

  One of the properties not found in conventional yeast for baking is a trait that results in a bread with a better flavor and shape. For example, as a method for improving the flavor of bread so far, the modification of the production process (Patent Document 1), the type and composition of auxiliary materials (Patent Document 2), the addition of fermentation flavor liquid (Patent Document 3) , Use of a novel yeast strain isolated from the natural world (Patent Document 4), application of a yeast mutant imparted with drug resistance (Patent Document 5), etc., which are said to have certain effects, This is not enough.

  In such a technical background, there has been a demand in the art for the development of bakery yeast and the like that have unprecedented properties and characteristics, and that can produce breads with better flavor and shape.

  On the other hand, in the brewing industry, in addition to yeast belonging to Saccharomyces cerevisiae, yeast belonging to Saccharomyces bayanus, which has good growth and fermentation at 8 to 10 ° C., is used for brewing beer, wine and the like. Sometimes. In addition, commercially available dry yeast for wine brewing includes a product in which a hybrid strain of Saccharomyces cerevisiae and Saccharomyces bayanus var. Further, there is a report that the flavor is improved when a strain produced by crossing Saccharomyces bayanus and Saccharomyces cerevisiae is used for winemaking (Non-patent Document 2). However, because yeast belonging to Saccharomyces bayanus is low-temperature fermentable, it is generally considered impossible to use it for bread making that requires fermentability in the middle temperature range. Until now, almost no bread has been tried.

JP2015-165777A Japanese Patent Laying-Open No. 2015-037393 Japanese Patent Laying-Open No. 2015-173633 JP 2012-191851 A Japanese Patent Application Laid-Open No. 2002-253211

International Journal of Food Microbiology, 204, 101-110, 2015 Applied Microbiology and Biotechnology, 99, 8597-8609, 2015

  An object of the present invention is to provide a practical bread-making yeast capable of producing breads with better flavor and shape, a method for producing breads using the yeasts, and the like.

  In order to achieve the above object, as a result of intensive studies, the present inventors obtained a better flavor by crossing Saccharomyces bayanus B9L3 strain with Saccharomyces cerevisiae H24U1M strain. The present inventors have found that a practical bread-making yeast capable of producing shaped breads can be obtained, and the present invention has been completed.

That is, the embodiment of the present invention is as follows.
(1) Bread yeast Saccharomyces sp. HB9 strain (NITE P-02470).
(2) A bread dough containing the yeast for bread making according to (1).
(3) Bread characterized by fermenting the bread dough described in (2) (for example, fermenting in a temperature range of 20 to 30 ° C., preferably 27 to 30 ° C.) and then baking (after completion of fermentation) Manufacturing method.
(4) Saccharomyces bayanus B9L3 strain (NITE P-02507) and Saccharomyces cerevisiae H24U1M strain (NITE P-02508), which has a better flavor and shape belonging to the genus Saccharomyces Of bread yeast that can be produced.

  According to the present invention, by crossing the Saccharomyces bayanus B9L3 strain with the Saccharomyces cerevisiae H24U1M strain, it is possible to produce breads with better flavor and shape, and fermentation that can be sufficiently used for actual bread making. A high-quality bread can be produced by producing a yeast strain for bread making having a high power and using the yeast strain for bread production.

FIG. 3 is a diagram showing an outline of a process for obtaining a cross strain performed in Example 1. Carbon dioxide from medium-sized bread dough prepared using each strain of HB9 strain (black circle mark), NBRC1344 strain (triangle mark), H24 strain (diamond mark), and HP467 strain (square mark), which was performed in Example 2 It is a graph which shows generation amount (ml / 5min / 20g dough). The horizontal axis represents fermentation time (hr).

  In the present invention, the B9L3 strain, which is a lysine-requiring mutant of the Saccharomyces bayanus NBRC1344 strain, which is known as a wine brewing yeast, and the uracil requirement of the Saccharomyces cerevisiae H24 strain, which is known as a bread-making yeast. The mutant H24U1M strain is crossed.

  The lysine-requiring mutant strain B9L3 and uracil-requiring mutant strain H24U1M may be obtained by a conventional method, and there is no particular limitation. For example, UV or chemical substances (ethyl methanesulfonic acid (EMS), N-methyl) -N-nitrosoguanidine (NTG, nitrous acid, etc.) etc. and NBRC1344 strain and H24 strain are mutated and then a predetermined selective medium (in the case of a lysine-requiring mutant, α-aminoadipic acid-containing medium, etc.) In the case of a mutant strain, a method of selecting with a 5-fluoroorotic acid-containing medium or the like) is exemplified. Then, it is preferable to perform hybridization by rare mating or spore-to-cell mating using these mutant strains, and hybridization by rare mating is particularly preferable, but the mating method is also limited to these. Is not to be done. The term “rare mating” means a method of selecting a triploid hybrid strain produced by crossing an a-zygous cell or α-zygous cell and a haploid vegetative cell generated in a diploid vegetative cell of yeast. The spore-to-cell junction means a method of selecting a diploid hybrid strain formed by the heterosexual junction between a yeast spore (haploid) and a yeast haploid vegetative cell.

  By such a cross between the B9L3 strain and the H24U1M strain, it is possible to easily obtain a baker's yeast hybrid strain that can produce bread having a better flavor and shape, such as the HB9 strain. And this HB9 strain | stump | stock is a yeast for bread making very useful in the hybrid strain | stump | stock obtained by this crossing, and has the following mycological properties.

(A) Morphological properties When cultured at 30 ° C. for 1 day in a YPD liquid medium (dry yeast extract 1.0%, high polypeptone 2.0%, glucose 2.0%), the cells are spherical or elliptical, The size is 5-7 μm × 6-9 μm, and multipolar budding. Moreover, the colonies when cultivated on a YPD agar plate medium at 30 ° C. for 1 day are light brown and shiny. Further, spore formation is observed when cultured on an SPO agar medium (potassium acetate 1.0%, yeast extract 0.1%, glucose 0.05%, agar 2.0%) at 25 ° C. for 14 days.
(B) Physiological properties Grows at a temperature of 20 to 37 ° C.
(C) Fermentation of sugar Glucose: +
Galactose: +
Sucrose: +
Maltose: +
Lactose:-
Raffinose: +
Trehalose:-
Melibiose: +
(D) Utilization of carbon source Glucose: ++
Galactose: ++
L-sorbose:-
Sucrose: ++
Maltose: ++
Cellobiose:-
Trehalose: +
Lactose:-
Melibiose:-
Raffinose: +
Merezitose:-
Inulin:-
Soluble starch:-
D-xylose:-
L-arabinose:-
D-arabinose:-
D-ribose:-
L-rhamnose:-
Ribitol:-
D-mannitol:-
Glycerol: +
Ethanol: ++
α-methylglucoside: +
Salicin:-
Succinic acid:-
Citric acid:-
Myo-inositol:-
D-Glucosamine:-

  Moreover, the B9L3 strain and the H24U1M strain, which are hybrid parent strains, have the following mycological properties.

<B9L3 stock>
(A) Morphological properties When cultured at 30 ° C. for 1 day in a YPD liquid medium (dry yeast extract 1.0%, high polypeptone 2.0%, glucose 2.0%), the cells are spherical or elliptical, The size is 6-9 μm × 4-7 μm, and multipolar budding. Moreover, the colonies when cultivated on a YPD agar plate medium at 30 ° C. for 1 day are light brown and shiny. Further, no spore formation was observed even when cultured on an SPO agar medium (potassium acetate 1.0%, yeast extract 0.1%, glucose 0.05%, agar 2.0%) at 25 ° C. for 7 days. .
(B) Physiological properties Grows at a temperature of 20 to 33 ° C.
(C) Fermentation of sugar Glucose: +
Galactose:-
Sucrose: +
Maltose: +
Lactose:-
Raffinose: +
Trehalose:-
Melibiose:-
(D) Utilization of carbon source Glucose: +
Galactose:-
L-sorbose:-
Sucrose: +
Maltose: +
Cellobiose:-
Trehalose: +
Lactose:-
Melibiose:-
Raffinose:-
Merezitose:-
Inulin:-
Soluble starch:-
D-xylose:-
L-arabinose:-
D-arabinose:-
D-ribose:-
L-rhamnose:-
Ribitol:-
D-mannitol:-
Glycerol:-
Ethanol:-
α-methylglucoside: −
Salicin:-
Succinic acid:-
Citric acid:-
Myo-inositol:-
D-Glucosamine:-

<H24U1M stock>
(A) Morphological properties When cultured at 30 ° C. for 1 day in a YPD liquid medium (dry yeast extract 1.0%, high polypeptone 2.0%, glucose 2.0%), the cells are spherical or elliptical, The size is 4-6 μm × 3-5 μm, and multipolar budding. Moreover, the colonies when cultivated on a YPD agar plate medium at 30 ° C. for 1 day are light brown and shiny. Further, no spore formation was observed even when cultured on an SPO agar medium (potassium acetate 1.0%, yeast extract 0.1%, glucose 0.05%, agar 2.0%) at 25 ° C. for 7 days. .
(B) Physiological properties Grows at a temperature of 20 to 35 ° C.
(C) Fermentation of sugar Glucose: +
Galactose: +
Sucrose: +
Maltose: +
Lactose:-
Raffinose: +
Trehalose:-
Melibiose:-
(D) Utilization of carbon source Glucose: ++
Galactose: ++
L-sorbose:-
Sucrose: ++
Maltose: ++
Cellobiose:-
Trehalose: +
Lactose:-
Melibiose:-
Raffinose: +
Merezitose: +
Inulin:-
Soluble starch:-
D-xylose:-
L-arabinose:-
D-arabinose:-
D-ribose:-
L-rhamnose:-
Ribitol:-
D-mannitol:-
Glycerol:-
Ethanol: ++
α-methylglucoside: −
Salicin:-
Succinic acid:-
Citric acid:-
Myo-inositol:-
D-Glucosamine:-

  These HB9 strain, B9L3 strain and H24U1M strain are all incorporated into the National Institute of Technology and Evaluation Microorganisms Deposit Center (2-5-8 Kazusa Kamashitsu, Kisarazu City, Chiba Prefecture, Japan 292-0818). Was deposited on May 11, 2017, and the B9L3 and H24U1M strains were deposited on July 14, 2017. The deposit numbers are NITE P-02470 and NITE, respectively. P-02507 and NITE P-02508.

  And using this yeast hybrid strain for bread making such as HB9 strain, bread is produced by a scratch method or the like in which the bread dough mixed with flour, water, sugar, salt, fat, yeast, etc. is fermented and then baked at once. However, the bread making method is not limited to this. In addition, since the yeast for breadmaking of the present invention, for example, HB9 strain, has a low temperature bread dough fermenting power (bread dough fermenting power in a temperature range of about 4 to 27 ° C.) or more, a low temperature bread dough is usually used. While raising the temperature to the fermentation temperature range (about 27-30 ° C.), fermenting the dough (simultaneously in parallel) and continuing the fermentation if necessary even after reaching the normal fermentation temperature range, the end of the fermentation A step of performing baking or the like later is also possible. Even if the bread dough is in the temperature range of 4 to 27 ° C., the fermentation proceeds to a certain degree or more, and the fermentation proceeds sufficiently even if the bread dough is in the temperature range of 27 to 30 ° C. Therefore, it is possible to shorten the production time of bread production using low temperature dough.

  Thus, the B9L3 strain, which is a lysine-requiring mutant of the strain belonging to Saccharomyces bayanus, which is a wine brewing yeast having excellent low-temperature growth ability, and the saccharomyces, which is a bakery yeast having a high bread dough fermentation ability, etc.・ Practical yeast for bread making that can produce bread with better flavor and shape by crossing with H24U1M strain, which is a uracil-requiring mutant of H. cerevisiae H24 strain, and has a certain degree of low-temperature bread dough fermentation ability. A strain can be produced, and the quality of bread can be improved by using the yeast strain for bread production.

  In the present invention, the bread with a better flavor and shape is at least one of the shape (including internal shape), aroma, taste, baked color, hue, and overall evaluation of these items after baking. It means that the above is equivalent to or better than the same type of bread produced with commercial baker's yeast, and in particular, at least one of the internal shape, aroma, taste, and overall evaluation of the bread after baking is the same kind produced with commercial baker's yeast. Means better than breads.

  Further, in the present invention, the standard that the yeast for baking has a certain level of low-temperature bread dough fermenting power is that the amount of carbon dioxide generation in bread dough comprising 5% by weight of sugar per 100% by weight of flour is the representative temperature in the low temperature range, Fermentation that is 15 mL or more when measured at 4 ° C. for 24 hours (10 g of bread dough), and 45 mL or more when measured at 30 ° C. for 2 hours (10 g of dough) as a typical temperature in a normal yeast yeast fermentation temperature zone It means that the ratio of the bread dough fermentation power at 4 ° C. to the bread dough fermentation power at 30 ° C. is 35% or more.

  Examples of the present invention will be described below, but the present invention is not limited to these examples, and various modifications can be made within the technical idea of the present invention.

(Acquisition of hybrid strain)
The hybrid strain of the present invention was obtained by the following method.

  Isolation of lysine-requiring mutant B9L3 from Saccharomyces bayanus NBRC1344 strain obtained from the Incorporated Administrative Agency, National Institute of Technology and Evaluation, by the method of Kitamoto (Japan Brewing Association, 84 [1], 34-37, 1989) did. On the other hand, from haploid strain H24 strain derived from baker's yeast strain Saccharomyces cerevisiae for frozen dough and showing mating type a, uracil by Kitamoto's method (Japan Brewing Association, 84 [12], 849-853, 1989). The auxotrophic strain H24U1M was isolated.

  Next, this B9L3 strain and the H24U1M strain were used for crossing by rare mating. Specifically, for both strains, the cells of one platinum loop were placed in a YPD medium (dry yeast extract: 1.0%, high polypeptone in a test tube (diameter 1.8 cm × length 10.5 cm): 2.0 ml, glucose: 2.0%, agar: 2.0%) was inoculated into 3 ml, and cultured with shaking (150 rpm) at 30 ° C. After 24 hours, 1 ml of the culture solution was aseptically centrifuged and the cells collected were washed twice with sterile water. The cells were suspended in 3 ml of a liquid MM medium (Yeast nitrogen base without amino acids: 0.67%, glucose: 2.0%), and cultured with shaking (150 rpm) at 30 ° C. for 24 hours. When 0.03 ml of this culture solution was inoculated into another new liquid MM medium (minimum liquid medium) and similarly cultured with shaking for 48 hours, the culture solution that was transparent immediately after inoculation became cloudy due to the growth of the cells. A hybrid strain HB9 was purely isolated by streaking the grown yeast cells in this culture medium on a MM agar plate medium. The outline of the process for obtaining this cross strain is shown in FIG.

(Bread dough fermentation test)
In order to confirm the bread dough fermentation power at 30 ° C. of the hybrid strain HB9 obtained in Example 1 with the NBRC1344 strain, the H24 strain, and the Saccharomyces cerevisiae HP467 strain, which is a commercial baker's yeast isolate, the following test was conducted. Carried out.

Each strain of HB9 strain, NBRC1344 strain, H24 strain and HP467 strain was added to 10 ml of YPD medium (dry yeast extract: 1.0%, high polypeptone: 2.0%, glucose: 2.0%) in a 50 ml Erlenmeyer flask. The culture was reciprocally shaken at 150 ° C. for 24 hours (150 rpm), and 0.6 ml of the YPS medium (bacterial yeast extract: 2.0%, bactopeptone: 4.0%, KH ₂ PO _{4 in a} 300 ml baffled Erlenmeyer flask was used. : 0.2%, MgSO ₄ · 7H ₂ O: 0.1%, NaCl: 2.0%, Adecanol LG-294: 0.05%, sucrose: 2.0%) The NBRC1344 strain was subjected to rotary shaking culture (150 rpm) at 30 ° C. for 48 hours, and the H24 and HP467 strains for 24 hours. The cultured cells were collected by centrifugation, washed twice with distilled water, and then placed on a dried absorbent plate for several minutes to obtain cultured cells. Although the solid content of the cultured cells is about 30%, an accurate numerical value is calculated by drying a part thereof. In the following experiments, the cultured cells were used for preparing the dough as a weight converted to a solid content of 33%.

  For each yeast, 10 ml of flour (strong), 5.5 ml of distilled water containing 0.5 g of sucrose and 0.2 g of NaCl and 1.0 ml of a suspension containing 0.2 g of yeast cells were mixed for 1 minute. The prepared low-sugar bread dough (containing 5% sucrose and 2% NaCl with respect to the weight of flour) is put in a 2.4 cm × 20 cm test tube, and the amount of generated carbon dioxide gas is introduced into a graduated cylinder in saturated saline solution at 30 ° C. The amount of carbon dioxide generated per 2 hours was measured as the bread dough fermentation power. These operations were all performed at 30 ° C.

  The results are shown in Table 1 below. The hybrid HB9 strain had a low sugar bread dough fermentation power at 30 ° C. of 45.4 ml / 2h / 10 g wheat flour, which was similar to the HP467 strain, which is a commercial baker's yeast. In other words, the hybrid strain HB9 is a wine brewing yeast, and the lysine-requiring mutant of the NBRC1344 strain, which has a low fermentability at normal bread dough fermentation temperatures, is one of the parent strains, and has a low sugar bread dough fermentation ability comparable to that of commercially available bread yeast. It became clear that the strain had

  Furthermore, in order to compare and confirm the ratio of the low sugar bread dough fermentation power at 30 ° C. and 4 ° C. of the HB9 strain with the H24 strain and the HP467 strain, the following test was performed.

  For each of the yeast strains HB9, H24 and HP467 obtained above, 5.5 g of distilled water containing 10 g of flour (strong), 0.5 g of sucrose and 0.2 g of NaCl, and 0.2 g of yeast cells Low-sugar bread dough (containing 5% sucrose and 2% NaCl based on the weight of flour) prepared by kneading 1.0 ml of a suspension containing 1% in a 2.4 cm × 20 cm test tube and generating carbon dioxide The amount was introduced into a graduated cylinder in saturated saline, and the amount of carbon dioxide gas generated per 30 hours at 30 ° C. and 24 hours at 4 ° C. was measured as the bread dough fermentation power. All these operations were performed at 30 ° C. or 4 ° C.

  The results are shown in Table 2 below. The hybrid HB9 strain has a ratio of the bread dough fermentation power at 4 ° C. to the bread dough fermentation power at 30 ° C. of more than 35%, which is higher than that of commercially available baker's yeast strains. It became clear that the strain had

  Furthermore, each time strain of HB9 strain, NBRC1344 strain, H24 strain, and HP467 strain was used, and changes with time of carbon dioxide fermentation from medium-sized bread dough without adding sugar were confirmed. First, for each yeast, 100 g of wheat flour (Nisshin Flour Milling Camellia), 2.0 g of yeast cells and 61.4 ml of distilled water were kneaded for 3 minutes with a pin mixer, and the temperature when mashed was 24.0 ± 1.0. The dough was prepared so that it might become ° C. And 20g of bread dough was divided | segmented and the change of the amount of carbon dioxide gas generated per 5 minutes was measured with the farmograph (Ato Co., Ltd. product).

  The results are shown in FIG. Carbon dioxide generation after 1 hour from the start of measurement is due to the yeast cells fermenting maltose produced by the action of amylases from starch in the wheat flour, but it is reduced when it is exhausted. Similar to the results in Table 1 above, the hybrid strain HB9 is a medium-sized bread dough fermentation similar to the commercial baker's yeast HP467 strain, with the lysine-requiring mutant of the NBRC1344 strain having a low medium-sized dough fermentation ability as one of the parent strains. It is clear that the HB9 strain is slightly behind the HP467 strain, but the fermentation is completed in 4.6 hours, and the maltose fermentability is increased. became.

(Bread quality confirmation test)
In order to compare and confirm the quality of bread produced by the middle seed method using the hybrid strain HB9 obtained in Example 1 or the commercial baker's yeast Saccharomyces cerevisiae HP467 strain, the following test was performed.

  Pin 210g of wheat flour (camellia), 7.2g of yeast cultured cells (HB9 strain) or 6.0g (HP467 strain, both solids 33%), 0.15ml (20mg / ml) ascorbic acid solution and 126ml distilled water The medium dough was kneaded with a mixer for 3 minutes, and the temperature at the time of kneading was 24.0 ± 1.0 ° C. After fermenting this at 30 ° C. for 4.5 hours, add 90 g of flour, 15.0 g of sugar, 6.0 g of salt, 15.0 g of shortening and 75 ml of distilled water, and knead for about 4 minutes. The main body dough was prepared so that the temperature was 30.0 ± 0.5 ° C. Further, after a floor time of 30 minutes at 30 ° C., the dough was divided by hand by 100 g and rounded to take a bench time of 15 minutes at 30 ° C. This was molded with a molder and subjected to final fermentation at 38 ° C. and 85% humidity for 55 minutes, followed by baking at 180 ° C. for 25 minutes. This was allowed to cool at room temperature, and the specific volume was calculated by measuring the weight and volume.

  The results are shown in Table 3 below. Although the specific volume of the bread produced using the HB9 strain was slightly lower than the specific volume of the bread produced using the HP467 strain, it was a value that could be sufficiently evaluated at 5.0 or higher.

  Next, for each prepared bread, sensory evaluation was performed with respect to volume, shape, baked color, internal shape, softness, hue, aroma, taste, and overall evaluation by eight trained panelists. The evaluation criteria are set as 50 points for bread prepared using the HP467 strain, and the average value from the score obtained by comparing and evaluating the bread prepared using the HB9 strain from 0 (bad) to 100 (good) Was calculated.

  The results are shown in Table 4 below. The bread produced using the HB9 strain is equivalent to or higher than the bread produced using the HP467 strain in any of the evaluation items, and in particular, the HP467 strain in the four items of internal shape, aroma, taste, and overall evaluation. It was a very good evaluation over the bread produced using

  From the above, by crossing Saccharomyces bayanus B9L3 strain with Saccharomyces cerevisiae H24U1M strain, breads with better flavor and shape can be produced, and practical bread making with fermenting power of low temperature dough It was shown that yeast strains can be produced, and breads and the like having a more favorable flavor and shape can be effectively produced by applying the strains.

  The present invention is summarized as follows.

  An object of the present invention is to provide a practical bread-making yeast capable of producing breads with better flavor and shape, a method for producing breads using the yeasts, and the like.

  And by crossing Saccharomyces bayanus B9L3 strain and Saccharomyces cerevisiae H24U1M strain, it is possible to obtain a practical bakery yeast that can produce breads with a better flavor and shape. Bread with a more favorable flavor and shape can be produced by using it for the production of foods.

The accession numbers of the microorganisms deposited in the present invention are shown below.
(1) Saccharomyces sp. HB9 strain (NITE P-02470).
(2) Saccharomyces bayanus B9L3 strain (NITE P-02507).
(3) Saccharomyces cerevisiae H24U1M strain (NITE P-02508).

Claims (4)

  Baking yeast Saccharomyces sp. HB9 strain (NITE P-02470).   A bread dough containing the bread-making yeast according to claim 1.   A method for producing bread, wherein the bread dough according to claim 2 is fermented and then baked.   Saccharomyces bayanus B9L3 strain (NITE P-02507) and Saccharomyces cerevisiae H24U1M strain (NITE P-02508) How to make yeast for bread.

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