Yeast extract for suppressing off-flavors

Abstract

[Abstract] [Problem] The purpose of the present invention is to provide: a β-glucan-containing yeast extract having a greater capability to suppress off-flavors of food and beverages as compared with a conventional product; and a flavor improvement method for food and beverages, the method employing said yeast extract. [Solution] A β-glucan-containing yeast extract, especially a yeast extract containing β-glucan having a molecular weight of 1000-6000 Da, was found to be having a greater capability to mask off-flavors of food and beverages as compared with a conventional product.

Description

Technical Field

[0001] The present invention relates to a yeast extract for masking off-flavors of foods.

Background Art

[0002] When we put food or drink into our mouths, we feel various flavors. The various flavors of food and drink are involved in a complex manner with various other elements in addition to the basic elements representing the quality of taste, called basic tastes.

[0003] Among the flavors, there are those that are felt as unfavorable tastes. For example, bitterness, which is one of the basic tastes, is one of the taste qualities that make up the taste of food and drink. Foods and drinks with a well-balanced bitterness have high palatability, but if the bitterness is too strong, an unpleasant feeling spreads in the oral cavity and the palatability is significantly reduced. Regarding sourness, a refreshing sourness may be treated as a favorable taste in some cases, but a sourness with a stinging stimulus on the tongue is treated as an off-flavor and is shunned. Astringency is also called astringent taste and is a taste of tannin. This taste, like the faint astringency of preferred products such as green tea, is recognized as a taste that is liked to some extent, but the strong astringency represented by astringent persimmons is treated as a disliked taste and is generally avoided. The eg taste is the taste of so-called ash water and is an unpleasant taste that combines astringency and bitterness. Also, the greenish odor is an unpleasant taste that combines the plant odor of vegetables with astringency and eg taste. The plant odor derived from stems and leaves and the soybean odor are considered to be a kind of greenish odor. Also, as a factor affecting the flavor derived from the container, there is a retort odor. This is not directly a taste, but an odor that closely affects the taste. Even in retort products made of simple materials, the retort odor transfers to the materials and becomes an off-flavor of the food. Also, retort tomato products and meat products have a strong retort odor and have a clearly different taste from those manufactured by other processing methods. From such things, the retort odor can also be treated as a kind of off-flavor. In addition to this, other unpleasant flavors such as a pungent taste, a metallic taste, an alkaline taste, etc., and tastes accompanied by an unpleasant feeling felt by their mixture are sometimes treated as unfavorable flavors, that is, off-flavors.

[0004] To reduce the undesirable flavors described above, various additives containing active ingredients have been developed. For example, Patent Document 1 describes the use of hesperidin glycosides alone or in combination with hesperidin as a flavor enhancer to improve bitterness, astringency, sourness, grassy taste, and astringency in food and beverages. Patent Document 2 describes a flavor-improving composition containing theanine as an active ingredient. Furthermore, Patent Document 3 describes a yeast extract composition that has the effect of masking the bitterness and astringency of salts, the fishy smell of fish and meat, and the odor of plant proteins. Patent Document 4 describes a method for improving the taste quality of amino acids and / or nucleic acids using γ-aminobutyric acid. In addition, Patent Document 5 shows a method for suppressing bitterness using orientin, a type of flavone. Patent Document 6 describes a bitterness inhibitor containing methyl salicylate as an active ingredient. However, since these require extraction and isolation from plants, there has been a need for a simpler method of suppressing bitterness. Patent Document 7 describes a bitterness masking agent characterized by containing yeast-derived peptides as an active ingredient and also containing 5'-ribonucleotides and umami amino acids. Patent Document 8 describes a method for adding a yeast extract to a general oral product having an unpleasant bitter taste, the yeast extract having a peptide content of 5% by weight or more, an RNA content of 5% by weight or more, a free amino acid content of 4% by weight or less, and preferably a dietary fiber content of 15% by weight or more. However, it was not known that yeast extracts containing β-glucan, particularly those containing β-glucan with a molecular weight of 1000 Da to 6000 Da, could mask off-flavors in food and beverages. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-318379 [Patent Document 2] Japanese Patent Application Publication No. 9-313129 [Patent Document 3] Japanese Patent Application Publication No. 61-249362 [Patent Document 4] Japanese Patent Publication No. 2004-275098 [Patent Document 5] Japanese Patent Publication No. 2012-85604 [Patent Document 6] Japanese Patent Publication No. 2012-95646 [Patent Document 7] Japanese Patent Publication No. 2009-278917 [Patent Document 8] Japanese Patent Publication No. 2015-019655 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0006] The present invention aims to provide a β-glucan-containing yeast extract for suppressing off-flavors, and a method for masking off-flavors using the yeast extract. [Means for solving the problem]

[0007] As a result of diligent research, the inventors discovered that yeast extract containing β-glucan, particularly yeast extract containing β-glucan with a molecular weight of 1000 Da to 6000 Da, can mask off-flavors, thus completing the present invention.

[0008] In other words, the present invention is (1) Yeast extract containing β-glucan for suppressing off-flavors. (2) The yeast extract for suppressing off-flavors according to (1), wherein the β-glucan described above is a β-glucan with a molecular weight of 1000 Da to 6000 Da. (3) The yeast extract of (1) or (2) is a yeast extract made from Torula yeast. (4) A method for producing the yeast extract according to (1) to (3), wherein the basidiomycete enzymes used in the production are a culture or culture extract of Pycnoporus coccineus. (5) A method for improving the flavor of food and beverages using a yeast extract for suppressing off-flavors that contains β-glucan as described in (1) to (3). [Effects of the Invention]

[0009] According to the present invention, by simply adding a small amount of yeast extract, which is a common food, to an oral product, unpleasant off-flavors of the product can be suppressed, the taste can be made more cohesive, and a natural flavor can be imparted. Since yeast extract is a common food and has low allergenicity, a highly safe off-flavor suppressant can be obtained. [Best Mode for Carrying Out the Invention]

[0010] In this invention, off-flavor refers to one or more flavors selected from the group consisting of bitterness, astringency, sourness, grassy taste, bitterness, plant-based taste, gritty taste, metallic taste, alkaline taste, and retort odor.

[0011] The yeast used as the raw material for the yeast extract of the present invention is not particularly limited as long as it is an edible yeast, and may be live yeast or dried yeast that has been appropriately dried by known methods. For example, wine yeast, baker's yeast, Torula yeast, sake yeast, beer yeast, etc., can be used. More specifically, although not limited to these, the yeast used in the present invention can preferably be Candida utilis or Saccharomyces cerevisiae or Saccharomyces pastorianus, which belong to the genus Saccharomyces to which beer yeast and baker's yeast belong. In the present invention, one or more of the above yeasts may be used.

[0012] The above-mentioned edible yeasts are commercially available from various manufacturers, and these commercially available edible yeasts can also be used as starting materials in this invention. Alternatively, yeast can be cultured and the cultured cells can be used as starting materials. As for the method of culturing the yeast, any known method suitable for that yeast may be used as appropriate.

[0013] In addition, the above edible yeast may be dry yeast, liquid or muddy yeast suspended in a solvent such as water or a buffer solution, or even dead yeast or live yeast, and its form is not limited.

[0014] In the method of the present invention, pretreated edible yeast may be used as a starting material. Here, the pretreatment includes washing with water, an acid or an alkali solution, a lower alcohol, etc., and homogenization treatment of edible yeast.

[0015] The yeast extract of the present invention can be produced by culturing yeast rich in β-glucan content, collecting and washing the yeast cells, inactivating the enzymes in the yeast cells with hot water, and then concentrating, sterilizing, and drying the extract obtained by adding a nuclease or a protease.

[0016] In the method according to the present invention, the β-glucan-containing yeast extract obtained as described above can also be used by using a fraction separated from β-glucan by a separation filtration membrane as needed. Specifically, it is desirable to use a fraction separated into a fraction molecular weight of 600,000 Da or less and 100 Da or more, preferably 1000 Da - 10,000 Da, more preferably 1000 Da - 6000 Da.

[0017] Separation filtration may be carried out according to a method known to those skilled in the art, and there is no need to use a special method. For example, for the membrane used for separation filtration, cellulose acetate, polysulfone, polyvinyl alcohol, ceramic, etc. can be used. Among them, ceramic is preferable. Also, either a batch method in which the entire amount of the liquid passes through or a cross-flow method in which the liquid is circulated may be used, but the cross-flow method is desirable in that the membrane is less likely to be blocked and can be used continuously for a long time.

[0018] In the present invention, the β-glucan-containing yeast extract is characterized in that it contains 3% by weight or more, preferably 3 - 10% by weight of β-glucan per solid content.

[0019] Furthermore, in addition to the above-mentioned characteristics, the β-glucan-containing yeast extract of the present invention may also have the effect of improving the texture of food, enhancing the richness of flavor, and improving the physical properties when used as an excipient for powders.

[0020] Therefore, the above-mentioned β-glucan-containing yeast extract can be used in various applications such as food, health foods, and functional ingredients by subjecting it to further processing as needed.

[0021] Further treatments that can be applied to β-glucan-containing yeast extract include, but are not limited to, concentration (heat concentration, membrane concentration), crystallization, pH adjustment, and drying (e.g., constant temperature drying, reduced pressure (vacuum) drying, freeze-drying, spray drying).

[0022] The β-glucan-containing yeast extract obtainable from edible yeast by the method of the present invention can also be mixed with other components and used as a β-glucan-containing composition. This β-glucan-containing composition may contain β-glucan in an amount of about 5% by weight or more, but is not limited to the following. Other components in the composition besides β-glucan include, for example, free amino acids, peptides, and salts.

[0023] Furthermore, according to another aspect of the present invention, a method for improving the flavor of food and beverages is provided, which involves adding the above-mentioned β-glucan-containing yeast extract to food and beverages.

[0024] The flavor improvement described in this invention refers to suppressing off-flavors in food and beverages and adjusting the overall taste. The amount of β-glucan-containing yeast extract of this invention added to food and beverages for flavor improvement is preferably 0.0001 to 1.5% by mass, more preferably 0.001 to 1.5% by mass, even more preferably 0.01 to 1.5% by mass, and even more preferably 0.025 to 1.0% by mass. Adding less than 0.0025% by weight does not show a clear effect, and adding more than 1.0% by weight may result in the flavor of the yeast extract itself being noticeable, and is also undesirable from a cost perspective.

[0025] Foods and beverages to which the β-glucan-containing yeast extract of the present invention is added may be in liquid, solid, or semi-solid form. Examples include beverages (e.g., coffee), vinegar, miso, soy sauce, meat extract, poultry extract, seafood extract, yeast extract, natural seasonings such as protein hydrolysates, spices such as spices and herbs, seasonings such as sauces, broths, dressings, mayonnaise, tomato ketchup, tomato sauce, and other sauces, soups such as clear soups, consommé soup, egg soup, seaweed soup, shark fin soup, potage, and miso soup, and noodles (soba, udon, ramen, pasta). Examples include soups, sauces, rice dishes such as porridge, rice gruel, and rice porridge, processed meat products such as ham, sausage, and cheese, processed seafood products such as dumplings, minced meat, fish cakes, dried fish, salted seafood, and delicacies, processed vegetables such as pickles, snack foods such as potato chips, rice crackers, and cookies, cooked foods such as simmered dishes, fried dishes, grilled dishes, and curry, fruit and vegetable juices, soy milk, milk, dairy products, carbonated drinks, sports drinks, nutritional supplements, various tea beverages such as coffee, black tea, Japanese tea, barley tea, and mixed grain tea, alcoholic beverages such as shochu, sake, and beer, and supplements such as vitamins. If the food or beverage to which the flavor enhancer of the present invention is added is a seasoning, the seasoning to which the flavor enhancer of the present invention is added may be added to other food or beverages.

[0026] The flavor improvement method of the present invention can be carried out based on the above description relating to the β-glucan-containing yeast extract of the present invention. The addition of other additives usable in food and beverages may be done simultaneously with or separately from the addition of the β-glucan-containing yeast extract of the present invention. Furthermore, the β-glucan-containing yeast extract may be mixed with other additives usable in food and beverages and added to the food or beverage. The addition of the β-glucan-containing yeast extract to food and beverages also includes the method of adding the food or beverage to the β-glucan-containing yeast extract.

[0027] Another aspect of the present invention includes food and beverages to which the β-glucan-containing yeast extract of the present invention has been added. Furthermore, one preferred aspect of the present invention also includes food and beverages to which the β-glucan-containing yeast extract of the present invention has been added. Alternatively, food and beverages may be added to the β-glucan-containing yeast extract of the present invention, or food and beverages may be mixed with the β-glucan-containing yeast extract of the present invention. The food and beverages to which the β-glucan-containing yeast extract of the present invention has been added, as well as the methods of addition, are the same as described above. [Examples]

[0028] The present invention will be further described in detail by the following examples, but the present invention is not limited thereto. Unless otherwise specified, "%" means weight percent.

[0029] [Example 1] In this example, a β-glucan-containing yeast extract was prepared from edible yeast according to the method of the present invention.

[0030] Preparation of basidiomycete-produced enzymes (1) As an example of a basidiomycete, we selected Pycnoporus coccineus and its spore suspension (10 7 2 ml of (1 g / ml or more) was inoculated into 20 ml of seed medium (1 g / l calcium chloride, 1 g / l magnesium sulfate, 2 g / ml ammonium sulfate, 2 g / l monopotassium phosphate, 50 g / l sucrose, 30 g / l corn steep liquor, pH 7.0), and incubated in a 200 ml flask at 28°C and 200 rpm for 48 hours to obtain the seed culture completion solution.

[0031] (2) 2 ml of the obtained seed culture completion solution was transferred to 20 ml of main medium (1 g / l calcium chloride, 1 g / l magnesium sulfate, 2 g / l ammonium sulfate, 2 g / l monopotassium phosphate, 80 g / l sucrose, 35 g / l defatted soybean flour, pH 6.0), and cultured in a 200 ml flask at 28°C and 200 rpm for 96 hours to obtain the main culture completion solution. The main culture completion solution was filtered through filter paper, and the obtained enzyme solution was vacuum dried to obtain a dried powder of enzymes produced by Pyrocotyle cyanescens.

[0032] Preparation of enzymes produced by actinomycetes (1) Spore suspension of Streptomyces aureus (10 7 (1 or more particles / ml) 1. Inoculate a platinum loop into 20 ml of seed medium (soluble corn starch 30 g / l, corn steep liquor 30 g / l, ammonium sulfate 1 g / l, magnesium sulfate 0.5 g / l, calcium carbonate 3 g / l, pH 7.0), and incubate in a 200 ml Erlenmeyer flask at 28°C and 200 rpm for 24 hours to obtain the seed culture completion solution. (2) 1 ml of the obtained seed culture completion solution was transferred to 200 ml of main medium (soluble corn starch 30 g / l, corn steep liquor 15 g / l, defatted soy flour 25 g / l, ammonium sulfate 1 g / l, magnesium sulfate 0.5 g / l, calcium carbonate 3 g / l, pH 7.0), and incubated in a 200 ml flask at 28 °C and 200 rpm for 40 hours to obtain the main culture completion solution. (3) 20 ml of the obtained main culture solution was stirred at 28°C and 200 rpm for 3 hours, then 1.6 ml of isobutanol was added, and the mixture was stirred again at 28°C and 200 rpm for 3 hours to lyse the cells and obtain an enzyme-treated solution. This solution was dried at a temperature of 80°C or lower to obtain a dried powder of enzymes produced by actinomycetes.

[0033] Preparation of filtrate (Preparation Example 1) A 15% suspension was prepared by suspending dried Torula yeast in pure water, and the pH was adjusted to 7.7 with a 30% caustic soda solution. The actinomycete enzyme powder obtained above was added to this, and the mixture was heated from 40°C to 65°C for 5 hours, then held at 65°C for 3 hours. The pH at this time was 6.7-6.8. Next, it was cooled to 50°C and the pH was adjusted to 4.0 with 20% HCl. The basidiomycete enzymes obtained above were added. After reacting at 50°C for 12 hours, it was heat-sterilized at 90°C for 10 minutes. The reaction solution, cooled to 60°C, was filtered through a ceramic membrane with a pore size of 0.1-0.2 μm. The residue was stirred with three times the volume of pure water, filtered again, and the filtrate was combined with the above filtrate. The pH was adjusted to 5.5 with a 30% sodium hydroxide solution, and the mixture was concentrated to Bx55-65 by thin-film flow-feed vacuum concentration.

[0034] [Example 2] In this example, the carbohydrate components contained in the preparation prepared as described above were measured. The carbohydrate components were estimated by subtracting the α-glucan content from the total glucose amount.

[0035] Measurement of carbohydrate components The carbohydrate content of the preparation was measured as follows: 0.1 g of the preparation was boiled with 1000 μL of 2N hydrochloric acid for 3 hours to acid hydrolyze the polysaccharide. The amount of glucose released by this acid hydrolysis was measured using a Hitachi AS-2000 high-performance liquid chromatography system. A Shimadzu SCR-101H column was used, a differential refractive index detector was used for detection, and 4 mM sulfuric acid was used as the mobile phase. Separately, 0.1 g was dissolved in 990 μL of 0.08 M phosphate buffer (pH 4.5), and then 10 μL of amyloglucosidase (Sigma-A9913) was added and the mixture was treated at 60°C for 30 minutes. The amount of glucose released by this enzymatic treatment was measured using a Hitachi AS-2000 high-performance liquid chromatography system. A Shimadzu SCR-101H column was used, a differential refractive index detector was used for detection, and 4 mM sulfuric acid was used as the mobile phase. The glucose content obtained by enzymatic treatment was subtracted from the glucose content obtained by acid hydrolysis treatment to determine the content of the target carbohydrate component.

[0036] result Acid hydrolysis and amyloglycosidase treatment were performed separately, and glucose production was confirmed in both cases. The former produced a larger amount of glucose than the latter. Since the preparation was derived from the filtrate obtained by microfiltration of the yeast enzyme treatment solution, the carbohydrates in the preparation were considered to be β-glucans that are not broken down by amyloglycosidase. The β-glucan content of the preparation was 5.2%.

[0037] [Example 3] (Preparation Example 2) The samples also included fractions obtained by separating the concentrated solution from Preparation Example 1 using separation filtration membranes (Microza UF, Asahi Kasei Chemicals) and dialysis membranes (Biotech CE, REPLIGEN) to molecular weight cutoffs of 6000 Da or higher, 1000 Da-6000 Da, and 1000 Da or lower. The amount of fractionated sample added was calculated from the recovery rate during fractionation, and the equivalent amount was added when adding 0.1% of the concentrated solution obtained in Preparation Example 1.

[0038] [Example 3] The preparations obtained in Preparation Example 1 and Preparation Example 2 were added at concentrations of 0.1% and 0.041%, respectively, to a commercially available diluted solution of grain vinegar and dissolved (Test Group 1). The acidity of the dissolved preparations was evaluated sensorily. A sample with no additives was used as a control.

[0039] Sensory evaluation was conducted by a panel of 10 experienced individuals. A commercially available diluted grain vinegar solution without the above additives was used as a control, and the evaluation was performed using the 7-point scale shown below. The average scores of each panel member are shown in Figure 1. 7 points: Significantly improved 6 points: Improving 5 points: Slightly improved 4 points: About the same as control 3 points: Slightly declining 2 points: Declining 1 point; significantly decreased Explanation of symbols in Figure 1 1: Control, 2: Adjustment example 2 (1000Da~6000Da) 0.041% addition 3: Adjustment example 1: 0.1% addition, The vertical axis shows the sensory evaluation score (on a 7-point scale).

[0040] As shown in Figure 1, yeast extract containing β-glucan clearly showed a significant inhibitory effect on acidity compared to the control, and it was confirmed that its active site was located in the fraction with a molecular weight of 1000 Da to 6000 Da. This effect was not observed in fractions with molecular weight cutoffs of 6000 Da or more, or 1000 Da or less. Furthermore, when glucanase (Sumizyme TG (manufactured by Shin Nippon Chemical Co., Ltd.)) was applied to the yeast extract, the inhibitory effect decreased, suggesting that β-glucan in the 1000 Da to 6000 Da range is the center of activity.

[0041] [Example 4] 0.05% of the preparation obtained in Preparation Example 1 was added to a commercially available simmering seasoning liquid and dissolved (Test Section 2). Sensory evaluation of the dissolved product revealed that the sharpness of the vinegar felt mainly at the beginning and the acidity felt in the middle and later parts of the taste were milder, and a sweet and savory flavor was added.

[0042] [Example 5] 0.1% of the preparation obtained in Preparation Example 1 was added to commercially available potato salad (Test Group 3). Sensory evaluation of the added product revealed that it suppressed the sharp acidity, resulting in a milder flavor, and added a natural richness and umami.

[0043] [Example 6] Commercially available chicken meatballs (chicken thigh) were mixed with 0.3% of the preparation obtained in Preparation Example 1 (Test Group 4). Sensory evaluation of the mixed meatballs revealed that the initial pungent sourness and the subsequent sourness were milder, and the sweet and savory flavor of the chicken was enhanced.

[0044] [Example 7] Commercially available ground chicken was mixed with 0.2% of the preparation obtained in Preparation Example 1 (Test Group 5). Sensory evaluation of the mixed product showed that the chicken flavor was enhanced and prolonged by the sweetness and umami, while the flavor of the chicken meat was suppressed.

[0045] [Example 8] 0.1% of the preparation obtained in Preparation Example 1 was added to commercially available hot pot soup base (containing potassium chloride) (Test Group 6). Sensory evaluation of the added product showed that the astringency derived from potassium chloride, mainly perceived from the initial taste to the middle of the flavor, was suppressed, and the taste was more harmonious.

[0046] [Example 9] 0.2% of the preparation obtained in Preparation Example 1 was added to a commercially available cabbage seasoning liquid (Test Group 7). Sensory evaluation of the added preparation revealed that it enhanced the overall umami flavor and suppressed the characteristic grassy taste of cabbage.

[0047] [Example 10] A granular soy protein base was prepared consisting of plant protein (minced soy meat type), salt, refined sugar, and modified starch. 30 g of this granular soy protein base was dissolved in 100 ml of hot water to prepare a soy protein soup. To this soy protein soup, 0.064%, 0.082%, and 0.2% of the fractions with a molecular weight cutoff of 6000 Da or more obtained in Preparation Example 2, the fractions with a molecular weight cutoff of 1000 Da to 6000 Da, and the preparation obtained in Preparation Example 1 were added and dissolved, respectively (Test Group 8). The dissolved samples were sensory evaluated for the flavor, astringency, and bitterness of the plant protein. A sample with no additives was used as a control. The sensory evaluation was performed in the same manner as in Example 3.

[0048] As shown in Figure 2, yeast extract containing β-glucan clearly showed a significant inhibitory effect on the flavor, astringency, and bitterness of plant proteins compared to the control, and it was confirmed that its active site was located in the fraction with a molecular weight of 1000 Da to 6000 Da. This effect was not observed in fractions with molecular weight cutoffs of 6000 Da or more, or 1000 Da or less. Furthermore, when glucanase (Sumizyme TG (manufactured by Shin Nippon Chemical Co., Ltd.)) was applied to the yeast extract, the inhibitory effect decreased, suggesting that β-glucan in the 1000 Da to 6000 Da range is the center of activity. Explanation of symbols in Figures 2-5 1: Control (additive-free group) 2: Preparation example 2 fraction (molecular weight 6000 or more) 3: Preparation Example 2 Fractions (Molecular Weight 1000-6000) 4: Preparation Example 1 The vertical axis shows the sensory evaluation score (on a 7-point scale).

[0049] [Example 11] Commercially available hot pot soup base (containing 0.5% potassium chloride) was dissolved by adding 0.032%, 0.041%, and 0.1% of the fractions with a molecular weight cutoff of 6000 Da or more, the fractions with a molecular weight cutoff of 1000 Da to 6000 Da obtained in Preparation Example 2, and the preparation obtained in Preparation Example 1, respectively (Test Section 10). The dissolved samples were sensory evaluated for the astringency of potassium chloride. A sample with no additives was used as a control. The sensory evaluation was performed in the same manner as in Example 3.

[0050] As shown in Figure 3, yeast extract containing β-glucan clearly showed a significant inhibitory effect on the astringency of potassium chloride compared to the control, and it was further confirmed that its active site was in the fraction with a molecular weight of 1000 Da to 6000 Da. This effect was not observed in fractions with molecular weight cutoffs of 6000 Da or more, or 1000 Da or less. Furthermore, when glucanase (Sumizyme TG (manufactured by Shin Nippon Chemical Co., Ltd.)) was applied to the yeast extract, the inhibitory effect decreased, suggesting that β-glucan in the 1000 Da to 6000 Da range is the center of activity.

[0051] [Example 12] Commercially available hot pot soup base (containing 1.0% potassium chloride) was dissolved by adding 0.032%, 0.041%, and 0.1% of the fractions with molecular weight cutoffs of 6000 Da or more, 1000 Da-6000 Da obtained in Preparation Example 2, and the preparation obtained in Preparation Example 1, respectively (Test Section 11). The bitterness of potassium chloride in the dissolved mixture was evaluated sensorily. A sample with no additives was used as a control. The sensory evaluation was performed in the same manner as in Example 3.

[0052] Yeast extract containing β-glucan showed a significant inhibitory effect on the bitterness of potassium chloride compared to the control, and it was confirmed that its active site was located in the fraction with a molecular weight of 1000 Da to 6000 Da. This effect was not observed in fractions with molecular weight cutoffs of 6000 Da or higher, or 1000 Da or lower. Furthermore, when glucanase (Sumizyme TG (manufactured by Shin Nippon Chemical Co., Ltd.)) was applied to the yeast extract, the inhibitory effect decreased, suggesting that β-glucan in the 1000 Da to 6000 Da range is the center of activity. [Industrial applicability]

[0053] As described above, the present invention provides a β-glucan-containing yeast extract that has a high flavor-improving effect and suppresses off-flavors in food and beverages. [Brief explanation of the drawing]

[0054] [Figure 1] Effects of the present invention in Example 3 [Figure 2] Effect of the present invention in Example 10: Flavor of plant protein [Figure 3] Effect of the present invention in Example 10: Astringency [Figure 4] Effect of the present invention in Example 10: Bitterness [Figure 5] Effects of the present invention in Example 11

Claims

1. A yeast extract for suppressing off-flavors, comprising Torula yeast as a raw material, and containing 5% by weight or more of β-glucan with a molecular weight of 1000 Da to 6000 Da.

2. A method for improving the flavor of food and beverages using a yeast extract for suppressing off-flavors that contains β-glucan as described in claim 1.

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