Bacteriostatic composition, bacteriostatic method, method for producing processed food, and processed food

Abstract

To provide a composition that exhibits excellent bacteriostatic performance.SOLUTION: A bacteriostatic composition comprises (A) melanoidin produced from at least one selected from xylose and ribose and at least one selected from phenylalanine and proline as a reaction substrate, and (B) a chelating agent. It is preferable that the chelating agent (B) is at least one selected from citric acid or a salt thereof and condensed phosphoric acid or a salt thereof. It is also preferable that the composition further contains at least one selected from organic acids or salts thereof other than the chelating agent. It is also preferable that the organic acid or a salt thereof is acetate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a bacteriostatic composition using melanoidin, a bacteriostatic method, a method for producing a processed food, and a processed food. [Background technology]

[0002] In the food industry, there has been a demand in recent years for improved food shelf life, partly from the perspective of reducing food waste. In particular, for processed foods such as boxed lunches and prepared meals, a distribution and sales format has become widespread in recent years in which processed foods are mass-produced in factories or in-store kitchens, then transported and stored at low temperatures (chilled zone) so that the processed foods do not freeze, before reaching consumers. In addition, a distribution format known as "frozen chilled" has also developed in recent years, in which processed foods are distributed in a frozen state and then thawed and sold. Processed foods stored, distributed, and / or sold in the chilled zone (chilled foods) are thus more susceptible to spoilage and deterioration due to microbial growth than retort foods, which are sealed in containers and heated and pressurized. Therefore, high-level bacteriostatic technology is required.

[0003] Patent Document 1 describes a method for producing an antibacterial composition, which includes producing melanoidin by heating a reducing sugar selected from xylose or ribose and an amino acid selected from phenylalanine or proline, and incorporating the melanoidin as an active ingredient.

[0004] Patent Document 2 describes a food preservative characterized by containing one or more members selected from the group consisting of amino acids such as glycine and cysteine, lower fatty acid esters, sugar esters, vitamin B1 esters, polymerized phosphates, basic proteins and peptides such as protamine and nisin, antibacterial substances extracted from licorice, aqueous extracts of chili peppers, polysaccharides consisting of sugars, sugar acids and amino sugars and their partial hydrolysates, spices or plant components, alcohols, glucono-delta-lactone, conjugated linoleic acid and melanoidin.

[0005] Patent Document 3 describes a method for preventing the decay and mildew of food and drink by adding a melanoidin substance to the food and drink. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2023 / 068112 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-27588 [Patent Document 3] Special Publication No. 48-14042 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the bacteriostatic effect of conventional bacteriostatic compositions is not sufficient. Therefore, an object of the present invention is to provide a bacteriostatic composition having an excellent bacteriostatic effect. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have surprisingly found that by combining a specific melanoidin with a chelating agent, the bacteriostatic effect is significantly improved compared to conventional methods. We also found that the bacteriostatic effect was significantly improved by using a specific melanoidin for bacteriostasis under specific pH conditions. The present invention provides the following configurations. [1] (A) a melanoidin produced from one or more species selected from xylose and ribose and one or more species selected from phenylalanine and proline as reaction substrates; (B) a chelating agent. [2] The bacteriostatic composition according to [1], wherein the chelating agent is one or more selected from citric acid or a salt thereof, and condensed phosphoric acid or a salt thereof. [3] The bacteriostatic composition according to [1] or [2], which contains one or more organic acids or salts thereof other than chelating agents. [4] The bacteriostatic composition according to [3], which contains an acetate salt. [5] The bacteriostatic composition according to any one of [1] to [4], which contains, as a reaction substrate, melanoidin produced from xylose and one or more selected from phenylalanine and proline. [6] The reaction substrate comprises melanoidin produced from one or more selected from xylose and ribose and one or more selected from phenylalanine and proline, A bacteriostatic composition used under conditions of pH 5.8 or less. [7] The bacteriostatic composition according to [6], which contains brewed vinegar. [8] A bacteriostatic method comprising a step of treating food with the bacteriostatic composition according to any one of [1] to [7]. [9] A method for producing a processed food, comprising a step of blending the bacteriostatic composition according to any one of [1] to [7].

[10] A processed food containing the bacteriostatic composition according to any one of [1] to [7].

[11] (A) a melanoidin produced from one or more species selected from xylose and ribose and one or more species selected from phenylalanine and proline as reaction substrates; (B) a bacteriostatic composition for lactic acid bacteria or yeast, comprising a chelating agent. [Effects of the Invention]

[0009] According to the present invention, there are provided a composition having superior bacteriostatic properties compared to conventional compositions, a method for effectively bacteriostatically inhibiting microorganisms using the composition, processed foods that can improve the shelf life by using the composition, and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0010] First, a preferred embodiment of the bacteriostatic composition of the present invention will be described. The bacteriostatic composition of this embodiment preferably contains (A) a melanoidin produced from one or more selected from xylose and ribose and one or more selected from phenylalanine and proline as a reaction substrate, and (B) a chelating agent.

[0011] <Melanoidin> The bacteriostatic composition of the present invention contains, as reaction substrates, melanoidin produced from one or more selected from xylose and ribose and one or more selected from phenylalanine and proline (hereinafter also referred to as "specific melanoidin"). In the present invention, the specific melanoidin contains a Maillard reaction product of one or more selected from xylose and ribose and one or more selected from phenylalanine and proline. Melanoidin refers to a brown pigment produced by the Maillard reaction. In the food industry, melanoidin is considered to be important in relation to food processing and storage, aroma component purification, and antioxidant component production.

[0012] The substrate for the Maillard reaction that produces a specific melanoidin may contain reducing sugars other than xylose and ribose, and examples thereof include aldoses such as glucose, galactose, mannose, xylose, erythrose, threose, ribose, arabinose, lyxose, and allose, and ketoses such as erythrulose, xylulose, ribulose, psicose, fructose, and sorbose. In the substrate for the Maillard reaction that produces a specific melanoidin, the proportion of one or more species selected from xylose and ribose among the reducing sugars is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, particularly preferably 70% by mass or more, and especially preferably 90% by mass or more.

[0013] The substrate for the specific melanoidin may contain amino acids other than phenylalanine and proline, such as glycine, serine, threonine, alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, histidine, isoleucine, leucine, lysine, methionine, tryptophan, tyrosine, and valine. The substrate for the specific melanoidin preferably contains at least one amino acid selected from phenylalanine and proline at a ratio of 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, particularly preferably 70% by mass or more, and especially preferably 90% by mass or more.

[0014] The Maillard reaction is carried out by subjecting the above-mentioned reducing sugars and amino acids as reaction substrates to heat treatment. The reaction substrates are preferably subjected to heat treatment as a solution dissolved in a solvent such as water, for example, as an aqueous solution. Heating conditions such as temperature and time are not particularly limited as long as melanoidin is produced, and can be appropriately determined by those skilled in the art. For example, the higher the temperature, the shorter the reaction time, so it is more efficient to carry out the reaction at as high a temperature as possible. The reaction may be carried out at, but is not limited to, about 100°C to about 130°C, preferably about 115°C to about 125°C, for example, for about 30 to 100 minutes, preferably about 50 to 80 minutes. For example, the reaction may be carried out under high-pressure conditions using an autoclave or the like. The Maillard reaction can be carried out, for example, under conditions of pH 5 to 10, and the pH is preferably 7.

[0015] Although not limited thereto, for example, the molar ratio of one or more selected from xylose and ribose to one or more selected from phenylalanine and proline is preferably 100:10 to 200, more preferably 100:50 to 150, in terms of the former:latter.

[0016] In the present invention, the Maillard reaction product obtained as above may be used as the specific melanoidin as is, or may be purified by appropriate solvent extraction or the like. The Maillard reaction product may be dried and used as a powdered melanoidin. The drying method is not particularly limited, but preferred are reduced pressure drying using a freeze dryer, vacuum drying, drying in a dry atmosphere, drying using a dehydrating agent, air drying, etc., and reduced pressure drying using a freeze dryer is particularly preferred.

[0017] The bacteriostatic composition of this embodiment preferably contains, as a reaction substrate, melanoidin produced from one or more species selected from xylose and one or more species selected from phenylalanine and proline, in that it has a high bacteriostatic effect.

[0018] Although not limited thereto, the bacteriostatic composition of this embodiment preferably contains 10 mmol or more, more preferably 50 mmol or more, and particularly preferably 100 mmol or more of the specific melanoidin per 100 g of solid content, calculated as one or more selected from phenylalanine and proline as reaction substrates. Furthermore, although not limited thereto, the content of the specific melanoidin per 100 g of solid content, calculated as one or more selected from phenylalanine and proline as reaction substrates, may be 1000 mmol or less, or may be 500 mmol or less. It is preferable that the amount is within the same range when converted into one or more species selected from xylose and ribose, which are reaction substrates.

[0019] The bacteriostatic composition preferably contains the specific melanoidin in an amount of 1% by mass, more preferably 5% by mass or more, and particularly preferably 10% by mass or more, on a dry mass basis. The upper limit of the content of the specific melanoidin in the bacteriostatic composition on a dry mass basis may be, for example, 99.9% by mass or less, 99% by mass or less, 95% by mass or less, or 90% by mass or less.

[0020] The bacteriostatic composition of this embodiment is preferably used to contain 0.1 mmol or more of the specific melanoidin per 100 g of processed food, calculated as one or more selected from xylose and ribose as reaction substrates, more preferably 0.5 mmol or more, and particularly preferably 1 mmol or more. Furthermore, the bacteriostatic composition of this embodiment may contain 100 mmol or less, or may contain 50 mmol or less, of the specific melanoidin per 100 g of processed food, calculated as one or more selected from phenylalanine and proline as reaction substrates. It is preferable that the amount is within the same range when converted into one or more species selected from xylose and ribose, which are reaction substrates.

[0021] The bacteriostatic composition of this embodiment is used by adding the specific melanoidin to processed foods in an amount of preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and preferably 0.5% by mass or more, as a dry mass. The bacteriostatic composition of this embodiment may also be used by adding the specific melanoidin to processed foods in an amount of 5% by mass or less, or 3% by mass or less.

[0022] <Chelating agent> A chelating agent is a compound capable of forming a chelate complex with a metal ion. The present inventors have found that combining a chelating agent with a specific melanoidin can provide particularly effective bacteriostasis. The chelating agent used in this embodiment may be any (grade) suitable for use in food and beverage applications, and examples thereof include citric acid, gluconic acid, malic acid, phytic acid, condensed phosphoric acids such as pyrophosphoric acid, metaphosphoric acid, polyphosphoric acid, and hexametaphosphoric acid, ethylenediaminetetraacetic acid, and salts thereof. Examples of salts include alkali metal salts such as sodium salts and potassium salts, and alkaline earth metal salts such as calcium salts.

[0023] In this specification, amino acids, sugars, and their Maillard reaction products are not considered to be chelating agents.

[0024] Among the above chelating agents, one or more selected from polycarboxylic acids or salts thereof, and condensed phosphoric acids or salts thereof are preferred, as they can effectively enhance the bacteriostatic activity of melanoidin. The polycarboxylic acid or its salt is preferably one having a total of three or more carboxyl groups and hydroxyl groups in the molecule, more preferably one having a total of four or more carboxyl groups and hydroxyl groups, and particularly preferably citric acid or a salt thereof. Furthermore, as the condensed phosphoric acid, a condensed phosphoric acid having three or more phosphorus atoms in one molecule is particularly preferred, a condensed phosphoric acid having four or more phosphorus atoms is more preferred, and a condensed phosphoric acid having five or more phosphorus atoms is particularly preferred. These may be used alone or in combination of two or more.

[0025] Furthermore, the chelating agent used in the present embodiment preferably has a large molecular weight, for example, preferably 200 or more, more preferably 500 or more, and even more preferably 1000 or more. The molecular weight of the chelating agent is not particularly limited, but is preferably, for example, 3000 or less from the viewpoint of availability, etc.

[0026] Although not limited thereto, the bacteriostatic composition of this embodiment preferably contains 0.5 mol or more of a chelating agent on a functional group basis per mol of one or more selected from phenylalanine and proline, which are reaction substrates of a specific melanoidin, more preferably 1 mol or more, particularly preferably 5 mol or more, and even more preferably 10 mol or more. Furthermore, although not limited thereto, the bacteriostatic composition of this embodiment may contain 100 mol or less, or even 50 mol or less of a chelating agent on a functional group basis per mol of one or more selected from phenylalanine and proline, which are reaction substrates of a specific melanoidin. It is preferable that the amount is within the same range when converted into one or more species selected from xylose and ribose, which are reaction substrates. Here, the functional group basis refers to the number of functional groups in the chelating agent, rather than the number of moles of the chelating agent. When the chelating agent is a carboxylic acid, the number of functional groups is the total number of carboxylic acid groups and hydroxyl groups in the molecule, e.g., 4 for citric acid. The number of functional groups of the chelating agent is, for example, 4 in the case of EDTA. Furthermore, if the chelating agent is a condensed phosphoric acid, the number of functional groups corresponds to the number of phosphorus atoms, which is 3 for tripolyphosphoric acid or a salt thereof, 4 for tetrapolyphosphoric acid or a salt thereof, and usually 10 to 23 for metaphosphoric acid (also known as "hexametaphosphoric acid").

[0027] The bacteriostatic composition of this embodiment preferably contains 0.06 mol or more of a chelating agent per mol of one or more selected from phenylalanine and proline, which are reaction substrates of a specific melanoidin, more preferably 0.1 mol or more, particularly preferably 0.5 mol or more, and even more preferably 1 mol or more. Furthermore, although not limited thereto, the bacteriostatic composition of this embodiment may contain 100 mol or less, or may contain 50 mol or less, of a chelating agent per mol of one or more selected from phenylalanine and proline, which are reaction substrates of a specific melanoidin. It is preferable that the amount is within the same range when converted into one or more species selected from xylose and ribose, which are reaction substrates.

[0028] Furthermore, the bacteriostatic composition preferably contains 0.1 parts by mass or more of a chelating agent per 1 part by mass of the dry mass of the specific melanoidin as a solid content, more preferably 0.5 parts by mass or more, and particularly preferably 1 part by mass or more. In the bacteriostatic composition, the content of the chelating agent per 1 part by mass of the dry mass of the specific melanoidin is, for example, preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

[0029] The content of the chelating agent in the bacteriostatic composition of this embodiment is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more, per 100 parts by mass of the total solid content of the bacteriostatic composition, from the viewpoint of improving bacteriostatic properties. The content of the chelating agent in the bacteriostatic composition of this embodiment is preferably 80 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of the total solid content of the bacteriostatic composition, from the viewpoint of avoiding an effect on taste, etc.

[0030] The content of the chelating agent in the processed food of this embodiment is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, based on the total mass of the processed food, from the viewpoint of improving bacteriostasis. The upper limit of the content of the chelating agent in the processed food of this embodiment is preferably 3% by mass or less, more preferably 1% by mass or less, based on the total mass of the processed food, from the viewpoint of minimizing the influence on the taste, etc. of the processed food.

[0031] <Other ingredients> Other components in the bacteriostatic composition are not particularly limited and can be selected appropriately as long as they do not impair the effects of the present invention, and examples thereof include organic acids or salts thereof, components having bacteriostatic activity (glycine, egg white lysozyme, etc.), emulsifiers (sucrose fatty acid esters, glycerin fatty acid esters, etc.), starches (starch, modified starch, etc.), dextrins (dextrin, cyclodextrin, indigestible dextrin, etc.), celluloses, thickening polysaccharides (xanthan gum, tamarind seed gum, etc.), etc. These can be used alone or in combination of two or more.

[0032] Among these, it is preferable to include an organic acid and / or an organic acid salt (hereinafter referred to as organic acids) since the bacteriostatic effect can be further improved by using it in combination with the specific melanoidin and chelating agent.

[0033] <Organic Acid and / or Organic Acid Salt> As described above, the bacteriostatic composition of this embodiment may contain one or more organic acids and / or organic acid salts other than chelating agents, and it is preferable to combine a specific melanoidin and a chelating agent with organic acids. The organic acids are used to adjust the pH of the bacteriostatic composition and support the bacteriostatic action of the melanoidin. These organic acids can be used alone or in combination of two or more, and typically, two or more can be used in combination so that the bacteriostatic composition has a desired pH. The organic acids include those having a total of one carboxyl group and one hydroxyl group, and those having a total of two or more carboxyl groups and one hydroxyl group but low chelating ability. These are treated as organic acids other than chelating agents in this specification. Specific examples include organic acids such as acetic acid, lactic acid, fumaric acid, succinic acid, adipic acid, sorbic acid, propionic acid, tartaric acid, maleic acid, oxalic acid, and ferulic acid, as well as salts thereof. Hereinafter, the amount of "organic acids" referred to in this specification refers to the amount of organic acids other than the chelating agent.

[0034] As the salts of the various organic acids mentioned above, it is preferable to use alkali metal salts and alkaline earth metal salts in terms of bacteriostatic effect and taste. Examples of alkali metal salts include sodium salts and potassium salts, and examples of alkaline earth metal salts include calcium salts.

[0035] In the bacteriostatic composition of the present invention, the organic acids preferably contain at least an acetate salt from the viewpoints of high bacteriostatic activity, easy availability, solubility, and buffering power. Furthermore, the acetate salt is more preferably an alkali metal salt of acetic acid, and even more preferably sodium acetate.

[0036] When an acetate (preferably an alkali metal salt of acetic acid, particularly sodium acetate) is used in combination with an organic acid other than an acetate as the organic acid, the acetate preferably accounts for 50% by mass or more, and more preferably 80% by mass or more, of the total mass of the organic acids, depending on the desired pH and the buffering power of the organic acids.

[0037] From the viewpoint of improving microbial safety, the acetate content in the processed food of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, based on the total mass of the processed food. From the viewpoint of minimizing the influence on the taste of the processed food, the upper limit of the acetate content in the processed food of the present invention is preferably 3% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, based on the total mass of the processed food.

[0038] Furthermore, the bacteriostatic composition of this embodiment may contain, for example, vinegar as an acetic acid source. For example, brewed vinegar is a liquid seasoning fermented from grains, fruits, vegetables, other agricultural products, honey, alcohol, and sugars, and is classified into grain vinegar, fruit vinegar, etc. Examples of grain vinegar include rice vinegar, black rice vinegar, and black barley vinegar. Examples of fruit vinegar include apple vinegar and grape vinegar. The acid component of brewed vinegar is acetic acid, and vinegars with an acidity, calculated as an acetic acid equivalent, of 4.0% or more (4.2% for grain vinegar and 4.5% for fruit vinegar) fall under the category of brewed vinegar. The acidity of the brewed vinegar of this embodiment is not particularly limited, but is preferably 5 to 20, and more preferably 10 to 20, for example. For example, as can be seen from a comparison of Tables 9 and 10 below, a good antibacterial effect can also be obtained when melanoidin is used in combination with organic acids such as brewed vinegar. Because brewed vinegar can be labeled as a food product, it is expected that melanoidin and brewed vinegar will be widely used in food products.

[0039] Although not limited thereto, when the bacteriostatic composition of this embodiment contains organic acids, it preferably contains 0.5 mol or more of organic acids per mol of one or more selected from phenylalanine and proline, which are reaction substrates of a specific melanoidin, more preferably 1 mol or more, and particularly preferably 2.5 mol or more. Furthermore, although not limited thereto, the content of organic acids in the bacteriostatic composition of this embodiment may be 100 mol or less, or may be 50 mol or less, per mol of one or more selected from phenylalanine and proline, which are reaction substrates of a specific melanoidin. It is preferable that the amount is within the same range when converted into one or more species selected from xylose and ribose, which are reaction substrates.

[0040] Furthermore, the bacteriostatic composition of this embodiment preferably contains 0.01 parts by mass or more of organic acids per part by mass of the dry mass of the specific melanoidin, more preferably 0.03 parts by mass or more, and particularly preferably 0.05 parts by mass or more. In the bacteriostatic composition, the content of organic acids per part by mass of the dry mass of the specific melanoidin is, for example, preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

[0041] Although not limited thereto, when the bacteriostatic composition of this embodiment contains organic acids, it preferably contains 0.1 parts by mass or more of organic acids per 1 part by mass of the chelating agent, more preferably 0.2 parts by mass or more, and particularly preferably 0.3 parts by mass or more. Furthermore, although not limited thereto, when the bacteriostatic composition of this embodiment contains organic acids, it may contain 100 parts by mass or less, or may contain 50 parts by mass or less, per 1 part by mass of the chelating agent.

[0042] The content of organic acids in the bacteriostatic composition of the present invention is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and particularly preferably 20 parts by mass or more, based on 100 parts by mass of the total solid content of the bacteriostatic composition, from the viewpoint of improving bacteriostatic properties. The content of organic acids in the bacteriostatic composition of the present invention is preferably 90 parts by mass or less, and even more preferably 80 parts by mass or less, based on 100 parts by mass of the total solid content of the bacteriostatic composition, from the viewpoint of avoiding an influence on taste, etc.

[0043] The content of organic acids in the processed food of the present invention (the total amount when two or more types are used in combination) is preferably 0.1% by mass or more, and more preferably 0.2% by mass or more, based on the total mass of the processed food, from the viewpoint of improving microbial safety. The upper limit of the content of organic acid salts other than acetate salts in the processed food of the present invention is preferably 4% by mass or less, and more preferably 1.5% by mass or less, based on the total mass of the processed food, from the viewpoint of minimizing the effect on the taste, etc. of the processed food.

[0044] In the bacteriostatic composition of this embodiment, the action of the specific melanoidin and the chelating agent can effectively achieve bacteriostasis in the target food, and can impart high shelf life to the food. In particular, the bacteriostatic composition of the present disclosure has the excellent effect of imparting high shelf life to processed foods with a high pH, ​​such as processed foods with a pH of 5.8 or higher. Conventionally, processed foods with a high pH have faced the problem of insufficient bacteriostatic effects of organic acids due to the high pH of the processed food itself, even when a bacteriostatic agent containing organic acids is used during cooking. The present disclosure can solve this problem. The present disclosure is particularly effective in improving the shelf life of chilled foods, which are prone to microbial growth. The pH of processed foods in this specification is measured at 20 to 30°C, and a pH of 5.8 or higher at any temperature within this range is considered to be pH 5.8 or higher. If the processed food is in a solid form, the pH can be measured by diluting it 2 to 10 times by weight with ion-exchanged water or physiological saline and making it into a paste using a stomacher, food processor, mixer, or the like. Due to the high antibacterial effect of melanoidins, the pH of processed foods is preferably 8.0 or lower, and more preferably 7.0 or lower.

[0045] Furthermore, since the action of melanoidin is particularly well exhibited under conditions of pH 5.8 or less, it may be used in processed foods of that pH, for example, in processed foods of pH 4.0 or higher and 5.4 or lower.

[0046] The bacteriostatic composition of the present invention is used to prevent deterioration of food freshness and quality and improve its shelf life. The types of foods to which the bacteriostatic composition of the present invention can be applied are not particularly limited. For example, it may be uncooked foods made from various ingredients such as vegetables, beans, potatoes, wild vegetables, fruits, meat, poultry, seafood, and grains, or cooked or semi-cooked foods, so-called processed foods, such as prepared dishes, rice dishes, noodles, confectioneries, soups, dairy products, and tofu. Note that "semi-cooked" here refers to incomplete cooking. For example, semi-cooked foods refer to foods that have been prepared by seasoning, cutting, peeling, skewering, or flouring, and include, for example, foods that have been cooked but not yet seasoned, foods that have been coated and / or seasoned but not yet cooked, and cut vegetables. The bacteriostatic composition of the present invention is particularly useful for processed foods, especially prepared dishes, which are cooked foods that do not fall under the category of retort pouch foods. Examples of side dishes include simmered dishes, boiled dishes, grilled dishes, mixed dishes, steamed dishes, stir-fried dishes, fried dishes, soups, salads, etc.

[0047] The bacteriostatic composition of this embodiment is effective against a wide range of microorganisms, but is particularly effective in inhibiting the growth of lactic acid bacteria and yeast. Lactic acid bacteria and yeast have traditionally been easily contaminated during the production of foods such as chilled foods, and controlling their growth has traditionally been extremely difficult. In contrast, as shown in the examples below, it has been found that specific melanoidins have a good bacteriostatic effect on lactic acid bacteria and yeast, and that combining them with a chelating agent can provide an extremely excellent bacteriostatic effect. This demonstrates that the bacteriostatic composition of this embodiment is particularly useful as a bacteriostatic composition for processed foods. The types of lactic acid bacteria are not particularly limited. Generally, as lactic acid bacteria that are likely to be mixed in during food production, bacteria of the genus Lactobacillus, Amylolactobacillus, Holzapfelia, Bombilactobacillus, Companilactobacillus, Lapidilactobacillus, Agrilactobacillus, Schleiferilactobacillus, Lacticaseibacillus, Paralactobacillus, Latilactobacillus, Loigolactobacillus, Dellaglioa, Liquorilactobacillus, Ligilactobacillus, Lactiplantibacillus, Furfurilactobacillus, Paucilactobacillus, Limosilactobacillus, Secundilactobacillus, Levilactobacillus, Fructilactobacillus, Acetilactobacillus, Apilactobacillus, Lentilactobacillus, Leuconostoc, Lactococcus, Pediococcus, Weissella, Enterococcus, etc. can be mentioned. Also, as yeast flora, Wickerhamomyces, Metschnikowia, Candida, Saccharomyces, Brettanomyces, Zygosaccharomyces, Cryptococcus, Rhodotorula, Schizosaccharomyces, Kluyveromyces, Sporobolomyces, Saturnispora, etc. can be mentioned.

[0048] Next, a bacteriostatic method using the bacteriostatic composition of the present invention (hereinafter also referred to as "bacteriostatic method of the present invention"), a method for producing processed foods (hereinafter also referred to collectively as "method of the present invention"), and processed foods will be described below. In addition to the following explanations, the above explanation of the bacteriostatic composition of the present invention can be applied as appropriate.

[0049] The method for producing processed foods of the present invention includes a step of blending the bacteriostatic composition of the present invention. This blending step can be carried out, for example, by sprinkling, dusting, applying, or spraying the bacteriostatic composition onto a processed food that does not contain the bacteriostatic composition. Alternatively, it can be carried out by immersing a processed food that does not contain the bacteriostatic composition in a liquid bacteriostatic composition. Alternatively, it can be carried out by cooking or semi-cooking (e.g., cooking with heat) food materials using the bacteriostatic composition as a seasoning or part of other raw materials. The various treatments in these blending steps also correspond to the treatment of food with the bacteriostatic composition of the present invention.

[0050] The processed food of the present invention is typically a cooked food or semi-cooked food that is distributed frozen, refrigerated, or at room temperature. Examples of the processed food include the various processed foods described above. Specifically, for example, the processed food of the present invention may be a so-called retort food, or may be one that has not undergone pressure-heat sterilization treatment like a retort food.

[0051] The processed food of the present invention may contain starch. As mentioned above, starch has an inhibitory effect on bacteriostatic agents, but the processed food of the present invention has high microbial safety and can be stored for a long period of time even if it contains starch due to the action of the bacteriostatic composition of the present invention. The type of starch referred to here is not particularly limited, and for example, one type selected from cereal flour such as wheat flour and the above-mentioned unmodified starch and modified starch can be used alone or in combination of two or more types. From the viewpoint of achieving the effect of high microbial safety despite the inclusion of starch, the starch content in the processed food of the present invention may be preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 1% by mass or more, relative to the total mass of the processed food. There is no particular upper limit for the starch content in the processed food of the present invention, but it is preferably 5% by mass or less, more preferably 2.5% by mass or less, relative to the total mass of the processed food.

[0052] The processed foods of the present invention are typically cooked or semi-cooked foods that are stored, distributed, and / or sold frozen, refrigerated, or at room temperature. Specific examples include prepared foods (such as salads, boiled dishes, grilled dishes, boiled dishes, steamed dishes, stir-fried dishes, fried dishes, soups, and salads), rice dishes, noodles, confectioneries, soups, dairy products, and tofu.

[0053] The processed food of the present invention can be stored by ordinary storage means, for example, at room temperature, refrigerated, chilled, or frozen. Preferably, the processed food of the present invention is stored, distributed, and / or sold in a chilled state. The "chilled state" here refers to a state in which the product temperature of the processed food is low enough not to freeze. The product temperature of a chilled processed food is preferably 0 to 12°C, more preferably 0 to 10°C. [Example]

[0054] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The following control examples are within the scope of the above [6] or

[11] .

[0055] (Production Example 1) D-xylose and L-phenylalanine were dissolved in a phosphate buffer solution at pH 7.0 so that the D-xylose concentration was 40 mM and the L-phenylalanine concentration was 40 mM, and the solution was heated at 121°C in an autoclave for 60 minutes. (Production Example 2) A melanoidin-containing liquid was prepared in the same manner as in Production Example 1, except that proline was used instead of phenylalanine.

[0056] Test 1 (Control Example 1, Examples 1 and 2) (1) 4.4 g of TSB medium (tryptic soy broth, manufactured by Becton Dickinson) and 1.5 g of soluble starch (starch (soluble), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were dissolved in 94.1 g of water, and the pH was adjusted to 6.2 with the addition of hydrochloric acid. The mixture was then autoclaved at 121°C for 15 minutes to prepare 1.5-fold concentrated TSB medium containing starch. (2) The melanoidin-containing liquid obtained in Production Example 1 was mixed with the starch-added 1.5-fold concentrated TSB medium obtained in (1) (mass ratio 1:2) to prepare a melanoidin-added TSB medium. (3) The melanoidin-added TSB medium obtained in (2) was dispensed into 10 ml aliquots, and 1% by mass of trisodium citrate (dihydrate, also used in Examples 3 to 5, 11 to 13) or sodium tripolyphosphate (Ohira Chemical Industry Co., Ltd.) was added as a chelating agent. (4) A cocktail of four strains (Weissella viridescens, Leuconostoc mesenteroides, Leuconostoc citreum, and Leuconostoc pseudomesenteroides) was added to (3) at a target of 7 cfu / g. Specifically, the following was done: Stock strains of each bacterial species were streaked onto standard agar medium and cultured. Single colonies were then picked from the standard agar medium and inoculated into TSB medium, followed by 24-hour culture at 30°C. 0.1 mL of the culture was inoculated into 10 mL of fresh TSB medium and cultured overnight. The four resulting bacterial solutions were mixed with 0.1% by mass sterilized peptone water to prepare a four-strain mixture. The bacterial counts of the resulting preparations were measured using the surface smear plate method, and 100 μL was inoculated into 10 mL of the medium in (3) so that the bacterial count per gram of medium after inoculation was approximately 7 cfu / g. (5) After adding the lactic acid bacteria, the medium was stored at 10°C for 72, 120, and 144 hours. After storage, the number of bacteria in the medium was measured on a standard agar medium using the method described below. The number of bacteria was converted to a logarithm, and the initial number of bacteria was subtracted to calculate the number of proliferating bacteria. The results are shown in Table 1. The results in Table 1 are the maximum values ​​of triplicates (the same applies to the results in Tables 2 to 4, 6, 7, and 8 to 10 below).

[0057] <Method for measuring viable bacteria count> The number of viable bacteria was measured by the surface smear plate method, as follows: 0.1 mL of the sample solution or 0.1 mL of a 100-fold or 10,000-fold diluted sample solution was dropped onto the surface of a plate of agar medium that had been solidified in advance, and the sample was smeared evenly with a Conlarg rod and cultured. The culture medium and culture conditions used were aerobic culture at 30°C for 72 hours using standard agar medium. The viable cell count was calculated as the number of viable cells per 1 g of medium (cfu / g) by multiplying the number of colonies grown in the medium by the dilution factor.

[0058] [Table 1]

[0059] Table 1 shows that lactic acid bacteria tend to grow in the presence of soluble starch, even in the presence of specific melanoidins, but the present invention, which uses a chelating agent in combination with melanoidins, can particularly effectively suppress the increase in bacterial count.

[0060] Test 2 (Control Example 2, Examples 3 and 4) (1) 5.82 g of TSB medium (Tryptic Soy Broth, manufactured by Becton Dickinson) was dissolved in 94.2 g of water, and the pH was adjusted to 5.8 using hydrochloric acid. (2) 5 g of the TSB medium (1) was added to 5 g of commercially available rice porridge (Ajinomoto Co.'s "Shirogayu") and autoclaved at 121°C for 15 minutes. (3) To a portion of the TSB gruel medium (2), 1% by mass of trisodium citrate or 1% by mass of trisodium citrate and 0.5% by mass of sodium acetate was added as a chelating agent. (4) 5 g of the melanoidin-containing liquid produced in Production Example 1 was added to 10 g of the porridge-containing TSB medium autoclaved in (2) or 10 g of the TSB medium to which (3) had been added, and mixed. (5) Using the same procedure as in (4) of Test 1, a cocktail of four strains of lactic acid bacteria (Weissella viridescens, Leuconostoc mesenteroides, Leuconostoc citreum, and Leuconostoc pseudomesenteroides) was added at a target concentration of 7 cfu / g. (6) The samples were stored at 10°C for 72, 120, and 144 hours. After each time, the bacterial count was measured using the method described above. The bacterial count was converted to a logarithm, and the initial bacterial count was subtracted to calculate the number of proliferating bacteria. The results are shown in Table 2.

[0061] [Table 2]

[0062] Table 2 shows that lactic acid bacteria tend to grow in the presence of foods such as porridge, even in the presence of specific melanoidins, but in the present invention, growth can be effectively suppressed by adding a chelating agent, and that even more effective bacteriostasis can be achieved by adding an organic acid salt.

[0063] Test 3 (Control Example 3, Example 5) The amount of soluble starch was changed from 1.5% by mass to 1% by mass in Control Example 1 and Example 1. Other than that, the same procedures were followed as in Control Example 1 and Example 1. The results are shown in Table 3.

[0064] Examples 6 and 7 In Example 5, 1% by mass of sodium metaphosphate (Taihei Chemical Industry Co., Ltd.) or sodium polyphosphate (sodium tetrapolyphosphate, Taihei Chemical Industry Co., Ltd.) was added instead of 1% by mass of trisodium citrate. The rest of the experiment was the same as in Example 5. The results are shown in Table 3.

[0065] [Table 3]

[0066] As shown in Table 3, it can be seen that the bacteriostatic effect of combining a specific melanoidin with a chelating agent is excellent.

[0067] Test 4 (Control Example 4, Examples 8 to 10) (1) 5.82 g of TSB medium (Tryptic Soy Broth, manufactured by Becton Dickinson) was dissolved in 94.2 g of water, the pH was adjusted to 6.2 with hydrochloric acid, and the mixture was heated in an autoclave at 121°C for 15 minutes to prepare a double-concentration TSB medium. (2) 5 ml of the melanoidin-containing liquid produced in Production Example 1 was added to 5 ml of the TSB medium (1), and this was further added to 5 g of commercially available rice porridge ("Shiragayu" manufactured by Ajinomoto Co., Inc.). Several such mixtures were prepared. (3) To a portion of the TSB medium containing the melanoidin-containing gruel of (2), 0.25 to 1 mass % of sodium metaphosphate (Taihei Chemical Industry Co., Ltd.) was added as a chelating agent. (4) To 10 g of TSB medium containing melanoidin-containing porridge obtained in (2) or 10 g of the same with the addition of (3), a cocktail of four strains of lactic acid bacteria (Weissella viridescens, Leuconostoc mesenteroides, Leuconostoc citreum, Leuconostoc pseudomesenteroides) was added at a target concentration of 7 cfu / g using the same procedure as in (4) of Test 1. (5) The medium from (4) was stored at 10°C for 72, 120, and 144 hours. After each time, the bacterial count was measured using the method described above. The bacterial count was converted to a logarithm, and the initial bacterial count was subtracted to calculate the number of proliferating bacteria. The results are shown in Table 4.

[0068] [Table 4]

[0069] Below, data without using a chelating agent is shown for reference.

[0070] Test 5 (1) 5.82 g of TSB medium (Tryptic Soy Broth, manufactured by Becton Dickinson) was dissolved in 94.2 g of water and heated in an autoclave at 121°C for 15 minutes to prepare a double-concentration TSB medium. (2) The melanoidin-containing liquid obtained in Production Example 1 was mixed with the double-concentration TSB medium obtained in (1) at a mass ratio of 1:1 to prepare a melanoidin-added TSB medium. (3) Sterilized water and the double-concentrated TSB medium obtained in (1) were mixed in a mass ratio of 1:1 to prepare melanoidin-free TSB medium. (4) 150 μl of each of the media (2) and (3) was dispensed into a 96-well microplate. (5) Add 1 x 10 lactic acid bacteria to the medium (4). 3 CFU / g target was added. Specifically, the following was done: The stock strains were streaked onto standard agar medium and cultured, and then a single colony was picked from the standard agar medium and inoculated into TSB medium, followed by culturing at 30°C for 24 hours. 0.1 mL of the culture was inoculated into 10 mL of fresh TSB medium and cultured overnight. The bacterial count of the resulting bacterial solution was measured by the surface smear plate method. The bacterial solution was diluted with 0.1% by mass sterilized peptone water, and the bacterial count per 1 g of medium after inoculation was approximately 1 x 10 3 1.5 μL of the culture medium in (4) was inoculated to a concentration of cfu / g. (6) The incubation reader HiTS (Synix Co., Ltd.) was placed in an incubator at 10°C, and the absorbance at 660 nm was measured over time. (7) The absorbance difference obtained by subtracting the absorbance of a blank sample to which no bacteria had been added from the absorbance measured in (6) is shown in Table 5. The smaller the absorbance difference, the higher the bacteriostatic effect.

[0071] [Table 5]

[0072] Test 6 (evaluation) The melanoidin-containing liquids obtained in Production Examples 1 and 2 were evaluated by the following methods. (1) 4.4 g of TSB medium (Tryptic Soy Broth, manufactured by Becton Dickinson) was dissolved in 96.4 g of water, and the pH was adjusted to 5.8 by adding hydrochloric acid. The mixture was then heated in an autoclave at 121°C for 15 minutes to prepare a 1.5x concentrated TSB medium. (2) The melanoidin-containing liquid obtained in Production Example 1 or 2 and the 1.5-fold concentrated TSB medium obtained in (1) were mixed in a mass ratio of 1:2 to prepare a melanoidin-added TSB medium. (3) Sterilized water and the 1.5x concentrated TSB medium obtained in (1) were mixed in a mass ratio of 1:2 to prepare melanoidin-free TSB medium. (4) 10 mL of each of the media (2) and (3) was dispensed into test tubes. (5) Using the same procedure as in (4) of Test 1, a cocktail of four lactic acid bacteria species (Weissella viridescens, Leuconostoc mesenteroides, Leuconostoc citreum, and Leuconostoc pseudomesenteroides) was added at a target concentration of 7 cfu / g.

[0073] (6) After storage at 10°C for 120 and 144 hours, the bacterial count was measured using the method described above. The bacterial count was converted to a logarithm, and the initial bacterial count was subtracted to calculate the number of proliferating bacteria. The results are shown in Table 6.

[0074] [Table 6]

[0075] Test 7 The melanoidin-containing liquid obtained in Production Example 2 was evaluated by the following method. (1) 5.8 g of TSB medium (Tryptic Soy Broth, manufactured by Becton Dickinson) was dissolved in 94.2 g of water, and the pH was adjusted to 5.8 by adding hydrochloric acid. The mixture was then heated in an autoclave at 121°C for 15 minutes to prepare a double-concentration TSB medium. (2) The melanoidin-containing liquid obtained in Production Example 2 and the double-concentrated TSB medium obtained in (1) were mixed at a mass ratio of 1:1 to prepare a melanoidin-added TSB medium. (3) Sterilized water and the double-concentrated TSB medium obtained in (1) were mixed at a mass ratio of 1:1, and 1 mass % sodium acetate was added to prepare a sodium acetate-added TSB medium. (4) 10 mL of each of the media (2) and (3) was dispensed into test tubes. (5) The yeast strains Wickerhamomyces anomalus, Metschnikowia pulcherrima, and Candida anglica were added at a target of 100 cfu / g each. Specifically, we did the following: The stock strains were streaked and cultured on PDAc medium (BD potato dextrose agar supplemented with chloramphenicol), and then a single colony was picked from the PDAc medium and inoculated into TSB medium, followed by culturing at 25°C for 24 hours. 0.1 mL of the culture was inoculated into 10 mL of fresh TSB medium and cultured overnight. The bacterial count of the resulting bacterial solution was measured by the surface smear plate method. The bacterial solution was diluted with 0.1% by mass sterilized peptone water, and the bacterial count per 1 g of medium after inoculation was approximately 1 x 10 2 100 μL of the culture medium in (4) was inoculated to a concentration of cfu / g.

[0076] (6) After storage at 10°C for 72, 120, and 144 hours, bacterial counts were measured. For bacterial counts, PDAc medium was used instead of standard agar medium, and aerobic culture at 25°C for 4 days was used instead of aerobic culture at 30°C for 72 hours. The bacterial counts were converted to logarithms, and the initial bacterial count was subtracted to calculate the number of proliferating bacteria. The results are shown in Table 7.

[0077] [Table 7]

[0078] Test 8 (Examples 11 to 13, Control Example 5) <1> Manufacturing of powdered melanoidin D-xylose and L-phenylalanine were dissolved in phosphate buffer (pH 7.0) to a concentration of 40 mM D-xylose and 40 mM L-phenylalanine, and the solution was heated at 121°C for 60 minutes in an autoclave. The resulting 40 mM melanoidin-containing solution was freeze-dried for 4 days using a vacuum freeze dryer (Tokyo Rikakikai FDM-1000). The freeze-dried yield was 1.9%. Similar results were obtained when using a Scrum Genesis Pilot freeze dryer. <2> Verification of the bacteriostatic effect of powdered melanoidin (1) 2.9 g of TSB medium (Tryptic Soy Broth, manufactured by Becton Dickinson) was dissolved in 100 g of water, and the pH was adjusted to 5.8 using hydrochloric acid. (2) 10 g of the TSB medium (1) was added to 5 g of commercially available rice porridge (Ajinomoto Co.'s "Shirogayu") and autoclaved at 121°C for 15 minutes. (3) In Examples 11, 12, and 13, 0.5% by mass of trisodium citrate and 0.5% by mass of sodium acetate were added as chelating agents to a portion of the TSB medium containing gruel (2). (4) 15 g of the porridge-containing TSB medium autoclaved in (2) or 15 g of the same to which (3) had been added was added 0.5 mass%, 0.75 mass%, or 1 mass% of the powdered melanoidin obtained by the above method and mixed. (5) Using the same procedure as in (4) of Test 1, a cocktail of four strains of lactic acid bacteria (Weissella viridescens, Leuconostoc mesenteroides, Leuconostoc citreum, and Leuconostoc pseudomesenteroides) was added at a target concentration of 7 CFU / g. (6) The samples were stored at 10°C for 72, 120, and 144 hours. After each time, the bacterial count was measured using the method described above. The bacterial count was converted to a logarithm, and the initial bacterial count was subtracted to calculate the number of proliferating bacteria. The results are shown in Table 8. [Table 8]

[0079] With melanoidin alone, the number of proliferating bacteria after 120 hours and 144 hours at 10°C does not fall below five digits, but it has been found that effective bacteriostasis can be achieved by adding 0.5% by mass of trisodium citrate and 0.5% by mass of sodium acetate as chelating agents to powdered melanoidin.

[0080] Test 9: Verification of bacteriostatic effect using melanoidin in low pH range (1) A 1x concentration TSB medium (autoclaved) containing 1% by mass of soluble starch was prepared in the same manner as in Test 1 (1), except that the amounts of starch and powdered medium used were different. (2) The powdered melanoidin obtained by the above method was mixed with the starch-added TSB medium obtained in (1) at concentrations of 0.1 mass%, 0.25 mass%, or 0.5 mass%, to prepare melanoidin-free TSB medium and melanoidin-added TSB medium. (3) The melanoidin-free TSB medium and melanoidin-added TSB medium obtained in (2) were each dispensed in 10 ml portions, and hydrochloric acid was added to adjust the pH at 25°C to 4.6, 5.0, 5.4, and 5.8. (4) Using the same procedure as in (4) of Test 1, a cocktail of four strains of lactic acid bacteria (Weissella viridescens, Leuconostoc mesenteroides, Leuconostoc citreum, and Leuconostoc pseudomesenteroides) was added at a target concentration of 7 CFU / g. (5) The samples were stored at 10°C for 120 hours and 144 hours. After each time, the number of bacteria was measured using the method described above. The number of bacteria was converted to a logarithm, and the initial number of bacteria was subtracted to calculate the number of proliferating bacteria. The results are shown in Table 9.

[0081] [Table 9]

[0082] Test 10: Verification of the bacteriostatic effect of the combined use of melanoidin and brewed vinegar (1) A 1x concentration TSB medium (autoclaved) containing 1% by mass of soluble starch was prepared in the same manner as in Test 1 (1), except that the amounts of starch and powdered medium used were different. (2) The powdered melanoidin obtained by the above method was not added or was mixed at 0.25% by mass with the starch-added TSB medium obtained in (1). (3) The melanoidin-free TSB medium and melanoidin-added TSB medium obtained in (2) were mixed with 0.2% by mass and 0.5% by mass of brewed vinegar whose acidity had been adjusted to 13.5. (4) Hydrochloric acid was added to adjust the pH to 5.8 at 25°C. (5) Using the same procedure as in (4) of Test 1, a cocktail of four strains of lactic acid bacteria (Weissella viridescens, Leuconostoc mesenteroides, Leuconostoc citreum, and Leuconostoc pseudomesenteroides) was added at a target concentration of 7 CFU / g. (6) The samples were stored at 10°C for 120 hours and 144 hours. After each time, the bacterial count was measured using the method described above. The bacterial count was converted to a logarithm, and the initial bacterial count was subtracted to calculate the number of proliferating bacteria.

[0083] [Table 10]

Claims

1. (A) as reaction substrates, melanoidin produced from one or more species selected from xylose and ribose and one or more species selected from phenylalanine and proline; (B) a chelating agent.

2. 2. The bacteriostatic composition according to claim 1, wherein the chelating agent is at least one selected from the group consisting of citric acid or a salt thereof and condensed phosphoric acid or a salt thereof.

3. The bacteriostatic composition according to claim 1, further comprising at least one selected from organic acids or salts thereof other than chelating agents.

4. The bacteriostatic composition according to claim 3, wherein the organic acid or its salt other than the chelating agent comprises an acetate salt.

5. 2. The bacteriostatic composition according to claim 1, comprising, as a reaction substrate, melanoidin produced from xylose and one or more selected from phenylalanine and proline.

6. The reaction substrates include melanoidin produced from one or more selected from xylose and ribose and one or more selected from phenylalanine and proline, A bacteriostatic composition used under conditions of pH 5.8 or less.

7. The bacteriostatic composition according to claim 6, comprising brewed vinegar.

8. A bacteriostatic method comprising a step of treating food with the bacteriostatic composition according to any one of claims 1 to 7.

9. A method for producing a processed food, comprising a step of blending the bacteriostatic composition according to any one of claims 1 to 7.

10. A processed food comprising the bacteriostatic composition according to any one of claims 1 to 7.

Images