Powder bacteriostatic agent for processed food

Abstract

To provide novel means that prevents a foreign taste derived from chitosan and acetic acid from being perceived and does not impair an original flavor of a processed food even when chitosan and acetic acid are added to a processed food, in a bacteriostatic method for a processed food comprising chitosan and acetic acid as an effective component.SOLUTION: A powder bacteriostatic agent for a processed food includes acetic acid, sodium acetate, and chitosan, wherein the mass ratio of sodium acetate to acetic acid is more than 1.5:1 and less than 6.7:1.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a powdery bacteriostatic agent for processed foods, which comprises acetic acid, sodium acetate, and chitosan. [Background technology]

[0002] Chitosan is known as a polymeric natural antibacterial substance and is widely used as an antibacterial agent and bacteriostatic agent for various purposes. In particular, chitosan is preferred as an active ingredient in bacteriostatic agents for processed foods because it is derived from natural substances that are widely consumed, such as crab, shrimp, and mushrooms.

[0003] Chitosan is generally insoluble in water, but dissolves in acid, and when dissolved, the amino groups become positively charged (-NH3 + ) cationic polymer. These positively charged amino groups bind to the negatively charged cell walls of bacteria, inhibiting bacterial growth. In order for chitosan to exert its bacteriostatic properties, it is necessary to lower its pH using an acid or other agent and dissolve it in a solution. Therefore, it is commonly used in combination with an organic acid such as acetic acid as a bacteriostatic agent in processed foods. However, when chitosan and an organic acid are used together in processed foods, the processed foods may be imparted with an unpleasant astringent or sour taste, which is characteristic of chitosan and the organic acid, limiting the processed foods in which it can be used.

[0004] To solve these problems, a method has been proposed in which a large amount of glycine is added together with chitosan and an organic acid. For example, Patent Document 1 discloses a bacteriostatic agent for prepared foods, which is characterized by containing three active ingredients: glycine, acetic acid or sodium acetate, and chitosan, and which is adjusted to a pH of 5.6 to 6.0. Another proposed technique involves reducing the amount of glycine or acid and combining it with another bacteriostatic material (e.g., thiamine lauryl sulfate).

[0005] However, when used in large amounts, glycine can impart a sweet or bitter taste accompanied by a unique cooling sensation, and can cause burning during cooking (coloring due to the Maillard reaction), and thiamine lauryl sulfate can decompose upon heating to produce thiamine, which can affect the flavor. Therefore, even when glycine or thiamine lauryl sulfate is used, there is a problem that the processed foods in which it can be used are limited. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-034434 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide a new method for bacteriostasis of processed foods containing chitosan and acetic acid as active ingredients, which does not impair the original flavor of the processed food and does not produce any unpleasant taste derived from chitosan and acetic acid even when chitosan and acetic acid are added to the processed food. [Means for solving the problem]

[0008] As a result of intensive research to solve the above-mentioned problems, the inventors have found that in a processed food having a predetermined pH value to which acetic acid and sodium acetate are added in a predetermined mixing ratio together with chitosan as bacteriostatic active ingredients, the bacteriostatic effect is exerted while no off-taste originating from chitosan and acetic acid is perceived, and the original flavor of the processed food can be satisfactorily enjoyed.

[0009] The present invention is based on these new findings and includes the following inventions. [1] A powder bacteriostatic agent for processed foods, comprising acetic acid, sodium acetate, and chitosan, A bacteriostatic agent comprising sodium acetate in a mass ratio to acetic acid of greater than 1:1.5 and less than 6.7 (acetic acid:sodium acetate). [2] The bacteriostatic agent according to [1], which contains sodium acetate in a mass ratio relative to acetic acid of 1:1.9 to 2.9 (acetic acid:sodium acetate). [3] The bacteriostatic agent according to [1] or [2], characterized in that the bacteriostatic agent is formulated to be added to food in proportions of 0.1 to 0.2% by mass of acetic acid, 0.2 to 0.5% by mass of sodium acetate, and 0.05 to 0.12% by mass of chitosan. [4] A bacteriostatic agent according to any one of [1] to [3], wherein the processed food is a meat product or a seafood product. [5] Further, any of the bacteriostatic agents [1] to [4] containing glycine. [6] The bacteriostatic agent according to [5], characterized in that the bacteriostatic agent has a composition ratio for containing glycine in a food product at a ratio of 0.1 to 0.22% by mass. [7] A processed food containing acetic acid, sodium acetate, and chitosan as bacteriostatic active ingredients, A processed food containing sodium acetate in a mass ratio of more than 1.5 and less than 6.7 relative to acetic acid (acetic acid:sodium acetate), and adjusted to a pH of 5.5 to 6.5. [8] The processed food according to [7], wherein the pH is adjusted to 5.5 to 5.8. [9] The processed food according to [7] or [8], containing sodium acetate in a mass ratio relative to acetic acid of 1:1.9 to 2.9 (acetic acid:sodium acetate).

[10] Any of the processed foods [7] to [9] containing acetic acid in an amount of 0.1 to 0.2 mass%, sodium acetate in an amount of 0.2 to 0.5 mass%, and chitosan in an amount of 0.05 to 0.12 mass%.

[11] Any of the processed foods [1] to

[10] , which are meat products and processed seafood products.

[12] Additionally, any of the processed foods [1] to

[11] containing glycine.

[13] The processed food of

[12] containing glycine in an amount of 0.1 to 0.22 mass%.

[14] A method for producing a processed food, comprising adding acetic acid, sodium acetate, and chitosan as bacteriostatic active ingredients to the processed food, and adjusting the pH to a range of 5.5 to 6.5, The method of manufacturing, wherein sodium acetate is added to acetic acid in a mass ratio of more than 1:1.5 and less than 6.7 (acetic acid:sodium acetate).

[15] The method according to

[14] , wherein the pH is adjusted to a range of 5.5 to 5.8.

[16] The production method according to

[14] or

[15] , wherein sodium acetate is added to acetic acid in a mass ratio of 1:1.9 to 2.9 (acetic acid:sodium acetate).

[17] The manufacturing method according to any one of

[14] to

[16] , wherein acetic acid is added in an amount of 0.1 to 0.2 mass %, sodium acetate in an amount of 0.2 to 0.5 mass %, and chitosan in an amount of 0.05 to 0.12 mass %.

[18] The manufacturing method of any of

[14] to

[17] , wherein the processed food is a meat product or a seafood product.

[19] Furthermore, the manufacturing method according to any one of

[14] to

[18] , in which glycine is added to a processed food.

[20] The manufacturing method of

[19] , wherein glycine is added in an amount of 0.1 to 0.22 mass %.

[21] A method for inhibiting microbial growth in processed foods, comprising adding acetic acid, sodium acetate, and chitosan as bacteriostatic active ingredients to the processed foods and adjusting the pH to a range of 5.5 to 6.5, The method of adding sodium acetate to acetic acid in a mass ratio of greater than 1:1.5 and less than 6.7 (acetic acid:sodium acetate).

[22] The method according to

[21] , wherein the pH is adjusted to a range of 5.5 to 5.8.

[23] The method according to

[21] or

[22] , wherein sodium acetate is added to acetic acid in a mass ratio of 1:1.9 to 2.9 (acetic acid:sodium acetate).

[24] Any of the methods

[21] to

[23] , in which acetic acid is added in an amount of 0.1 to 0.2 mass%, sodium acetate in an amount of 0.2 to 0.5 mass%, and chitosan in an amount of 0.05 to 0.12 mass%.

[25] Any of the methods

[21] to

[24] , wherein the processed food is a meat product or a seafood product.

[26] Furthermore, glycine can be added to processed foods using any of the methods described in

[21] to

[25] .

[27] The method of

[26] , in which glycine is added at a rate of 0.1 to 0.22 mass %. [Effects of the Invention]

[0010] According to the present invention, a new method for bacteriostasis of processed foods containing chitosan and acetic acid as active ingredients can be provided, which does not impair the original flavor of the processed foods, and does not produce any unpleasant taste due to chitosan and acetic acid, even when chitosan and acetic acid are added to the processed foods. DETAILED DESCRIPTION OF THE INVENTION

[0011] I. Powder bacteriostatic agent for processed foods The present invention relates to a powdery bacteriostatic agent for processed foods, which comprises acetic acid, sodium acetate, and chitosan.

[0012] In the present invention, the term "processed food" refers to a processed food whose pH at 25° C. has been adjusted to pH 5.5 to 6.5, preferably pH 5.5 to 6.3, more preferably pH 5.5 to 5.8, and even more preferably pH 5.6 to 5.8. Adjusting the pH of the processed food to fall within this range is preferable because it does not impair the original flavor of the processed food or suppresses the impairing of the flavor, and the bacteriostatic active ingredients of the present invention, acetic acid, sodium acetate, and chitosan, can exhibit bacteriostatic effects.

[0013] The pH value of the processed food can be adjusted to a predetermined range by blending the processed food and adding the bacteriostatic agent of the present invention and, if necessary, a pH adjuster commonly used in the production of food and beverages.

[0014] Processed foods are foods that have been processed or cooked in some way and adjusted to the above pH, and there are no particular limitations on the type. Examples of processed foods include wheat (refined wheat), flours (rice flour, wheat flour, millet flour, soy flour, potato flour, prepared grain flour, and other flours), starches (wheat starch, corn starch, sweet potato starch, potato starch, tapioca starch, sago starch, and other starches), processed vegetables (canned and bottled vegetables, processed tomatoes, salted vegetables (excluding pickles), pickled vegetables, frozen vegetables, dried vegetables, vegetable tsukudani, and other processed vegetables), processed mushrooms, and processed fruits (canned and bottled fruits, jams, marmalades, and fruit butters, pickled fruits, dried fruits, and other processed vegetables). frozen fruit foods, other processed fruit products); tea, coffee and cocoa preparations (tea, coffee products, cocoa products); spices (black pepper, white pepper, red pepper, cinnamon, cloves, nutmeg, saffron, laurel, paprika, allspice, Japanese pepper, curry powder, mustard powder, wasabi powder, ginger, other spices); noodles and breads (noodles, breads); processed grain products (pregelatinized grains, processed rice products, oatmeal, breadcrumbs, gluten, barley tea, etc.) and other processed grain products); Confectioneries (biscuits, baked goods, rice crackers, fried sweets, Japanese fresh sweets, Western fresh sweets, semi-fresh sweets, Japanese dried sweets, candies, chocolates, chewing gum, candied sweets, snacks, frozen sweets, and other sweets); Bean preparations (anko, boiled beans, tofu, fried tofu, yuba, frozen tofu, natto, kinako, peanut products, roasted beans, and other bean preparations); Sugars (sugar, molasses, sugars); Konjac and other processed agricultural foods; Meat products (processed meat products, canned and bottled poultry meat, frozen processed poultry meat foods, and other meat products); Dairy products Products (milk, processed milk, dairy drinks, condensed milk and concentrated milk, milk powder, fermented milk and lactic acid bacteria drinks, butter, cheese, ice cream, and other dairy products); processed egg products (processed chicken eggs and other processed egg products); honey and other bee-based processed foods; processed seafood (dried seafood, salted and dried seafood, dried and boiled seafood, salted seafood, canned seafood, processed frozen seafood, fish paste products, fried kamaboko, and other processed seafood); processed seaweed (kelp, kelp processed products, dried laver, processed laver products, dried wakame seaweed, dried hijiki seaweed, dried arame seaweed, agar, and other processed seaweed);The term "processed food" as used herein includes one or more combinations selected from the group consisting of seasonings and soups (salt, miso, soy sauce, sauces, vinegar, seasoning-related products, soups, other seasonings and soups); edible oils and fats (edible vegetable oils and fats, edible animal oils and fats, edible processed oils and fats); cooked foods (cooked frozen foods, chilled foods, retort pouch foods, boxed lunches, prepared dishes, and other cooked foods); yeast; vegetable proteins and seasoned vegetable proteins; malt and malt extracts and malt syrup; powdered juices, etc.; beverages, etc. (drinking water, soft drinks, alcoholic beverages, ice, other beverages, etc.). Preferably, the term "processed food" as used herein includes one or more combinations selected from the group consisting of seasonings and soups (salt, miso, soy sauce, sauces, vinegar, seasoning-related products, soups, other seasonings and soups); edible oils and fats (edible vegetable oils and fats, edible animal oils and fats, edible processed oils and fats); cooked foods (cooked frozen foods, chilled foods, retort pouch foods, boxed lunches, prepared dishes, and other cooked foods); yeast; vegetable proteins and seasoned vegetable proteins; malt and malt extracts and malt syrup; powdered juices, etc.; beverages, etc. (drinking water, soft drinks, alcoholic beverages, ice, other beverages, etc.). " refers to meat products and processed seafood products, and more specifically includes ham, sausage, bacon, block roasted pork, beef jerky, roast chicken, fried chicken, chicken nuggets, salad chicken, hamburger steak, meatballs, processed seafood, etc., but is not limited to these. In particular, the present invention is preferably applied to processed foods that are packaged after cooking or before cooking and are then stored refrigerated (4°C to 10°C) or at room temperature for a certain period of time without being heat sterilized, and the bacteriostatic agent of the present invention can exert its bacteriostatic effect even in such processed foods.

[0015] In the bacteriostatic agent of the present invention, the blending ratio of "acetic acid" and "sodium acetate" is such that sodium acetate is contained in a mass ratio relative to acetic acid of more than 1.5 and less than 6.7 (acetic acid:sodium acetate) (for example, 1:1.6 to 6.5, 1:1.7 to 5, or 1:1.8 to 4), preferably 1:1.9 to 2.9, more preferably 1:2.9. By blending acetic acid and sodium acetate in the above ranges, off-flavors such as sourness, astringency, and bitterness derived from acetic acid and chitosan are not perceived or can be reduced in processed foods to which the bacteriostatic agent of the present invention has been added, and the original flavor of the processed food is not impaired or impairment of the flavor can be suppressed, which is preferable.

[0016] In the present invention, acetic acid and sodium acetate can be used in the form of a powder. The size of the powder is not particularly limited, but acetic acid preferably has a median diameter of less than 280 μm, e.g., 250 μm or less, 200 μm or less, 150 μm or less, or 100 μm or less. The lower limit is not particularly limited, but a powder form of 50 μm or more is preferred. Compared to acetic acid having a median diameter within the above range, acetic acid having a median diameter of 280 μm or more is less compatible with other powder raw materials such as sodium acetate and chitosan, and may result in a homogeneous mixture that is not uniform and exhibits a mottled appearance, which may impair the appearance of the bacteriostatic agent of the present invention (although this does not impair the bacteriostatic effect). The median diameter of acetic acid can be determined as the diameter at 50% height (median diameter: D50) in a cumulative distribution diagram (volume-based, integrated from the smallest particle diameter) obtained by laser analysis and laser scattering particle size distribution measurement.

[0017] In the present invention, purified products or synthetic products that are generally available for the production of foods and beverages can be used as acetic acid and sodium acetate, and those commercially available as food ingredients or food additives can also be used.

[0018] In the present invention, "chitosan" has a molecular weight of 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and although there is no particular upper limit, it is preferably 4,000,000 or less, more preferably 1,000,000 or less, and even more preferably 400,000 or less. The molecular weight of chitosan can be determined by the SEC-MALS method, which combines size exclusion chromatography (SEC) and a multi-angle light scattering detector (MALS).

[0019] Chitosan can be obtained by known methods, such as deacetylating chitin with a concentrated aqueous solution of sodium hydroxide. From the viewpoint of the solubility of chitosan in water, the degree of deacetylation of chitosan is preferably 70% or more, more preferably 75% or more, and even more preferably 80% or more. The upper limit is not particularly limited, but is preferably 100% or less, more preferably 95% or less, and even more preferably 90% or less. The origin of chitin is not particularly limited, and chitin derived from crustaceans such as crabs and shrimp, insects, shellfish, mushrooms, filamentous fungi (e.g., Aspergillus nigar), etc. can be used.

[0020] In the present invention, chitosan can be used in the form of powder, and purified products or synthetic products that are generally available in the production of foods and beverages can be used, as well as products that are commercially available as food ingredients or food additives.

[0021] The bacteriostatic agent of the present invention can exhibit a bacteriostatic effect when used in combination with chitosan and sodium acetate, and can contain chitosan in any amount that does not impair the original flavor of the processed food or that can suppress the impairing of the flavor.For example, the bacteriostatic agent contains chitosan in a composition ratio that allows it to be added to the processed food at a rate of 0.05% by mass or more, preferably 0.07% by mass or more.

[0022] The bacteriostatic agent of the present invention can contain acetic acid in any amount that satisfies the total amount of acetic acid and sodium acetate described below, so long as chitosan can exert a bacteriostatic effect and the original flavor of the processed food is not impaired or the impairment of the flavor can be suppressed. For example, the bacteriostatic agent contains acetic acid in a composition ratio that allows the addition of acetic acid to the processed food at a rate of more than 0.08% by mass, preferably 0.1% by mass or more.

[0023] The bacteriostatic agent of the present invention contains acetic acid and sodium acetate in a composition ratio that allows the total of acetic acid and sodium acetate to be added to processed foods at a rate of 0.2 to 0.7% by mass (e.g., 0.3 to 0.7% by mass, or 0.35 to 0.6% by mass), preferably 0.3 to 0.6% by mass, more preferably 0.39 to 0.54% by mass, and even more preferably 0.4 to 0.54% by mass.

[0024] The bacteriostatic agent of the present invention contains acetic acid, sodium acetate, and chitosan in a composition ratio that allows the addition of acetic acid to processed foods at 0.1 to 0.2 mass%; sodium acetate to 0.2 to 0.5 mass%; and chitosan to 0.05 to 0.12 mass%. Preferably, the bacteriostatic agent of the present invention contains acetic acid, sodium acetate, and chitosan in a composition ratio that allows the addition of acetic acid to processed foods at 0.1 to 0.18 mass%; sodium acetate to 0.26 to 0.4 mass%; and chitosan to 0.072 to 0.104 mass%, more preferably, the addition of acetic acid to processed foods at 0.1 to 0.14 mass%; sodium acetate to 0.3 to 0.4 mass%; and chitosan to 0.072 to 0.096 mass%.

[0025] By setting the blending amounts of acetic acid, sodium acetate, and chitosan in the bacteriostatic agent of the present invention within the above ranges, the processed food to which the bacteriostatic agent of the present invention has been added will not have or will have reduced perception of off-flavors such as sourness, astringency, and bitterness derived from acetic acid and chitosan, will not lose its original flavor, or will be prevented from losing its flavor, and will exhibit bacteriostatic action, which is preferable.In this specification, the proportion of each component amount in the processed food is the proportion amount relative to the total amount of the processed food to which the bacteriostatic agent of the present invention has been added, assuming that it is 100% by mass.

[0026] The bacteriostatic agent of the present invention may further contain glycine as needed in addition to the above-mentioned acetic acid, sodium acetate, and chitosan. By further adding glycine, the processed food to which the bacteriostatic agent of the present invention has been added can be free from or reduce the perception of off-flavors such as sourness, astringency, and bitterness derived from acetic acid and chitosan, and this is preferable because it contributes to preventing or suppressing the loss of the original flavor of the processed food.

[0027] In the present invention, glycine can be used in the form of a powder, and purified products or synthetic products that are generally available in the production of foods and beverages can be used, and products that are commercially available as food ingredients or food additives can also be used.

[0028] Glycine can be blended into the bacteriostatic agent of the present invention at a composition ratio that allows glycine to be added to processed foods at a rate of 0.1 to 0.22 mass%, preferably 0.1 to 0.20 mass%, more preferably 0.13 to 0.18 mass%, and even more preferably 0.13 to 0.17 mass%.

[0029] In addition to the above-mentioned active ingredients, the bacteriostatic agent of the present invention can further contain, as necessary, ingredients commonly used in the production of powder compositions and foods and beverages, within a range that does not impair the effects of the present invention. Examples of such other ingredients include, but are not limited to, sugars, excipients, disintegrants, lubricants, binders, diluents, buffers, suspending agents, thickeners, preservatives, antibacterial agents, antiseptics, antioxidants, UV absorbers, colorants, pigments, dyes, pigments, lubricants, plasticizers, solvents, solubilizers, isotonicity agents, seasonings, flavorings, vitamins, chelating agents, pH adjusters, etc.

[0030] The bacteriostatic agent of the present invention can be used as a bacteriostatic agent for inhibiting microbial growth in processed foods, and is preferable because the addition of the bacteriostatic agent of the present invention can exhibit bacteriostatic action without impairing the original flavor of the processed food or while suppressing the impairment of the flavor. The bacteriostatic agent of the present invention can be used in accordance with, but is not particularly limited to, the method for producing processed foods and / or the method for inhibiting microbial growth, which will be described in detail below.

[0031] II. Processed food The present invention also relates to a processed food containing acetic acid, sodium acetate, and chitosan as bacteriostatic active ingredients.

[0032] In the present invention, "processed food," "acetic acid," "sodium acetate," and "chitosan" are as defined above.

[0033] The processed food of the present invention contains sodium acetate in a mass ratio relative to acetic acid of more than 1.5 and less than 6.7 (acetic acid:sodium acetate) (for example, 1:1.6 to 6.5, 1:1.7 to 5, or 1:1.8 to 4), preferably 1:1.9 to 2.9, more preferably 1:2.9. By adjusting the blending ratio of acetic acid and sodium acetate to within the above ranges, off-flavors such as sourness, astringency, and bitterness derived from acetic acid and chitosan added as bacteriostatic active ingredients are not perceived or their perception can be reduced, and the original flavor of the processed food is not impaired or impairment of the flavor is suppressed, which is preferable.

[0034] The processed food of the present invention can contain chitosan in any amount that can exert a bacteriostatic effect when used in combination with acetic acid and sodium acetate, and that does not impair the original flavor of the processed food or that can suppress the impairing of the flavor.For example, the processed food contains chitosan in a proportion of 0.05% by mass or more, preferably 0.07% by mass or more.

[0035] The processed food of the present invention can contain acetic acid in any amount that satisfies the total amount of acetic acid and sodium acetate described below, so long as chitosan can exert a bacteriostatic effect and the original flavor of the processed food is not impaired or the impairment of the flavor can be suppressed. For example, the processed food contains acetic acid in a proportion of more than 0.08% by mass, preferably 0.1% by mass or more.

[0036] The processed food of the present invention contains acetic acid and sodium acetate in a total amount of 0.2 to 0.7% by mass (for example, 0.3 to 0.7% by mass, or 0.35 to 0.6% by mass), preferably 0.3 to 0.6% by mass, more preferably 0.39 to 0.54% by mass, and even more preferably 0.4 to 0.54% by mass.

[0037] The processed food of the present invention contains, as bacteriostatic active ingredients, 0.1 to 0.2 mass% of acetic acid, 0.2 to 0.5 mass% of sodium acetate, and 0.05 to 0.12 mass% of chitosan, preferably 0.1 to 0.18 mass% of acetic acid, 0.26 to 0.4 mass% of sodium acetate, and 0.072 to 0.104 mass% of chitosan, and more preferably 0.1 to 0.14 mass% of acetic acid, 0.3 to 0.4 mass% of sodium acetate, and 0.072 to 0.096 mass% of chitosan.

[0038] By setting the blending amounts of acetic acid, sodium acetate, and chitosan in the processed food of the present invention within the above ranges, it is possible to eliminate or reduce the perception of off-tastes such as sourness, astringency, and bitterness derived from acetic acid and chitosan added as bacteriostatic active ingredients, and it is possible to maintain the original flavor of the processed food or suppress the deterioration of the flavor, and to obtain bacteriostatic action, which is preferable. Note that the proportion of each component amount in the processed food is the proportion amount relative to the total amount of the processed food to which the bacteriostatic active ingredient has been added, assuming that it is 100% by mass.

[0039] The processed food of the present invention may further contain glycine as a bacteriostatic active ingredient, if necessary, in addition to the above-mentioned acetic acid, sodium acetate, and chitosan. The inclusion of glycine further prevents or reduces the perception of off-flavors such as sourness, astringency, and bitterness derived from the acetic acid and chitosan added as bacteriostatic active ingredients, which is preferable because it contributes to preventing or suppressing the impairment of the original flavor of the processed food.

[0040] In the present invention, "glycine" is as defined above.

[0041] The processed food of the present invention may contain glycine at a ratio of 0.1 to 0.22 mass %, preferably 0.1 to 0.2 mass %, more preferably 0.13 to 0.18 mass %, and even more preferably 0.13 to 0.17 mass %.

[0042] The processed food of the present invention is preferable because the addition of the bacteriostatic active ingredient can exert a bacteriostatic effect without impairing the original flavor of the processed food or suppressing the impairing of the flavor.

[0043] The processed food of the present invention can be produced according to, but not limited to, the method for producing a processed food and / or the method for inhibiting microbial growth described in detail below.

[0044] III. Methods for producing processed foods and methods for inhibiting microbial growth The present invention also relates to a method for producing processed foods, and a method for inhibiting microbial growth in processed foods, which comprises adding acetic acid, sodium acetate, and chitosan as bacteriostatic active ingredients to the processed foods.

[0045] In the present invention, "processed food," "acetic acid," "sodium acetate," and "chitosan" are as defined above.

[0046] The present invention includes adding acetic acid, sodium acetate, and chitosan as bacteriostatic active ingredients to a processed food, and adjusting the pH of the processed food to the above-mentioned predetermined range. The pH value of the processed food can be adjusted to the predetermined range by blending the processed food, adding the bacteriostatic active ingredients, and, if necessary, adding a pH adjuster commonly used in the production of foods and beverages. Once the blending of the processed food, the blending of the bacteriostatic active ingredients, and the pH adjuster that will bring the pH value of the processed food to the above-mentioned range have been determined, the step of adjusting the pH does not need to be carried out every time.

[0047] In the present invention, sodium acetate is added to processed foods at a mass ratio of 1:1.5 to 6.7 (acetic acid:sodium acetate) relative to acetic acid (e.g., 1:1.6 to 6.5, 1:1.7 to 5, or 1:1.8 to 4), preferably 1:1.9 to 2.9, more preferably 1:2.9. By setting the amounts of acetic acid and sodium acetate added within the above ranges, off-flavors such as sourness, astringency, and bitterness derived from acetic acid and chitosan added as bacteriostatic active ingredients are not perceived or their perception can be reduced, and the original flavor of the processed food is not impaired or impairment of the flavor is suppressed, which is preferable.

[0048] In the present invention, chitosan can exert a bacteriostatic effect when used in combination with acetic acid and sodium acetate, and can be added in any amount that does not impair the original flavor of the processed food or that can suppress the impairing of the flavor.For example, chitosan is added to the processed food in a proportion of 0.05% by mass or more, preferably 0.07% by mass or more.

[0049] In the present invention, acetic acid can be added to chitosan in any amount that satisfies the total amount of acetic acid and sodium acetate described below, so long as chitosan can exert a bacteriostatic effect and the original flavor of the processed food is not impaired or the impairment of the flavor can be suppressed. For example, acetic acid is added to the processed food in a proportion of more than 0.08% by mass, preferably 0.1% by mass or more.

[0050] In the present invention, acetic acid and sodium acetate are added to processed foods in such a proportion that the total of acetic acid and sodium acetate is 0.2 to 0.7% by mass (for example, 0.3 to 0.7% by mass, or 0.35 to 0.6% by mass), preferably 0.3 to 0.6% by mass, more preferably 0.39 to 0.54% by mass, and even more preferably 0.4 to 0.54% by mass.

[0051] In the present invention, the bacteriostatic active ingredients added to processed foods are 0.1 to 0.2 mass% of acetic acid, 0.2 to 0.5 mass% of sodium acetate, and 0.05 to 0.12 mass% of chitosan, preferably 0.1 to 0.18 mass% of acetic acid, 0.26 to 0.4 mass% of sodium acetate, and 0.072 to 0.104 mass% of chitosan, and more preferably 0.1 to 0.14 mass% of acetic acid, 0.3 to 0.4 mass% of sodium acetate, and 0.072 to 0.096 mass% of chitosan.

[0052] By setting the amounts of acetic acid, sodium acetate, and chitosan added within the above ranges, the off-flavors such as sourness, astringency, and bitterness derived from the acetic acid and chitosan added as bacteriostatic active ingredients are not perceived or can be reduced, the original flavor of the processed food is not impaired or the impairment of the flavor can be suppressed, and bacteriostatic action can be obtained, which is preferable. Note that the proportion of each ingredient amount in the processed food is the proportion amount relative to the total amount of the processed food to which the bacteriostatic active ingredients have been added, assuming that it is 100% by mass.

[0053] In the present invention, in addition to the above-mentioned acetic acid, sodium acetate, and chitosan, glycine may be further added to the processed food as a bacteriostatic active ingredient, if necessary. The addition of glycine can eliminate or reduce the perception of off-flavors such as sourness, astringency, and bitterness derived from the acetic acid and chitosan added as bacteriostatic active ingredients, and is therefore preferred because it contributes to maintaining the original flavor of the processed food or suppressing the loss of the flavor.

[0054] In the present invention, "glycine" is as defined above.

[0055] In the present invention, glycine can be added to processed foods at a ratio of 0.1 to 0.22 mass %, preferably 0.1 to 0.2 mass %, more preferably 0.13 to 0.18 mass %, and even more preferably 0.13 to 0.17 mass %.

[0056] In the present invention, acetic acid, sodium acetate, chitosan, and optionally glycine and a pH adjuster can be added at any stage in the production process of processed foods. This can be done by adding or mixing them with the raw materials of the processed foods, or by adding them to cooked or uncooked processed foods. Acetic acid, sodium acetate, chitosan, and optionally glycine and a pH adjuster can be added to the raw materials of processed foods or cooked or uncooked processed foods by any method, such as kneading, immersion, spraying, injection, or tumbling. Acetic acid, sodium acetate, chitosan, and optionally glycine and a pH adjuster can be added to the raw materials or processed foods simultaneously, or separately or in any combination. Acetic acid, sodium acetate, chitosan, and optionally glycine and a pH adjuster can be used in any form, and can be in the form of powder, tablet, capsule, paste, liquid, or gel, individually or in any combination. Alternatively, the addition of acetic acid, sodium acetate, and chitosan, and optionally glycine and a pH adjuster, may be carried out by utilizing the bacteriostatic agent of the present invention.

[0057] The processed foods obtained by the method of the present invention are preferable because the addition of the above-mentioned bacteriostatic active ingredient can exert a bacteriostatic effect without impairing the original flavor of the processed food or suppressing the impairment of the flavor. The present invention will be described below with reference to examples, but the present invention is not limited to these examples. [Example]

[0058] 1. Evaluation method for bacteriostatic effect Lactic acid bacteria (Leuconostoc mesenteroides (NBRC 100496)) was used as a bacteriostatic indicator strain.

[0059] The ground meat and sautéed onions were thawed, and all ingredients listed in Table 1 below were placed in a bowl and thoroughly mixed until the mixture was sticky. The mixture was then divided into portions for each test group, to which the bacteriostatic active ingredient was added according to the formulations listed in Table 2 below. Each portion was divided into 23g portions, molded, and baked in an oven (230°C x 8 minutes, 20% steam, medium-high fan speed). After cooling at room temperature, the mixture was aseptically placed in stomacher bags (10 bags x 100 CFU / g). The lactic acid bacteria listed above were inoculated into the stomacher bags (inoculation amount: 10 CFU / g to 100 CFU / g) and cultured at 10°C for 0, 24, 48, and 72 hours. The viable bacterial counts were then measured after storage. The remaining samples were then subjected to pH measurements and sensory testing. Commercially available food additive-grade glycine was used, and commercially available food additive-grade acetic acid, powdered acetic acid (40% acetic acid, 60% sodium acetate), and sodium acetate were mixed in the ratios shown in the table. Chitosan used was KiOuntrime-CsG (Seti Co., Ltd.). The amount of each bacteriostatic active ingredient is shown as a proportion of the total amount of the cooked hamburger steak (sample) to which the bacteriostatic active ingredient and lactic acid bacteria have been added, taken as 100% by mass.

[0060] After incubation, 180 mL of sterile saline was added to the stomacher bag containing the sample, and the stomacher was stomached for 60 seconds. This was used as the sample suspension, and after serial dilutions with sterile saline as necessary, the total viable bacterial count was measured using the pour plate method (incubated at 35°C for 48 hours) on standard agar medium. 1 mL of sample suspension was added per petri dish. The measurement results are shown as an average (n=3), but the sample at time 0, which corresponds to the initial stage of storage, was evaluated using n=1.

[0061] The bacteriostatic effect was expressed as the common logarithm of the value obtained by dividing the number of viable bacteria (B) in the hamburger steak without the addition of a bacteriostatic active ingredient at each incubation time by the number of viable bacteria (C) in the hamburger steak with the addition of a bacteriostatic active ingredient, as shown in the formula below. Bacteriostatic effect = log(B) / (C)

[0062] If the obtained value was 1.5 or more, it was evaluated as "◯" indicating that there was an effective bacteriostatic effect, and if it was less than 1.5, it was evaluated as "×" indicating that there was no effective bacteriostatic effect.

[0063] 2. Sensory test of taste The taste of cooked hamburger steaks (cooled to room temperature) containing the bacteriostatic active ingredient in each of the above formulations and having a predetermined pH value was evaluated by a trained panelist. The taste was evaluated on a scale of 1 to 5, with the hamburger steak of Example 1 (a cooked hamburger steak containing acetic acid and sodium acetate in a 1:2 ratio and having a pH value of 5.55) receiving a score of 3 (denoted as "Good"), those that were more preferable receiving a score of 4 to 5 (denoted as "Excellent"), and those that were less preferable receiving a score of 1 to 2 (denoted as "Poor").

[0064] 3.Results The formulations of the bacteriostatic active ingredient, the pH value (25°C) of the cooked hamburger steak, the evaluation results of the bacteriostatic effect, and the results of the sensory test for taste are shown in the following Table 2. Comparative Examples 1 and 2 show formulations of the bacteriostatic active ingredient specifically disclosed in the examples of Patent Document 1, and Comparative Example 3 shows a formulation of the bacteriostatic active ingredient that uses acetic acid and sodium acetate in combination and falls within the range disclosed in Patent Document 1.

[0065] [Table 1]

[0066] [Table 2]

[0067] In cooked hamburger steaks with a pH value of approximately 5.3 without using sodium acetate in combination with acetic acid as a bacteriostatic active ingredient, the sour taste derived from acetic acid was strongly felt, and it was confirmed that the pleasant flavor of the hamburger steak was not felt (Comparative Examples 1 and 2).

[0068] Furthermore, even when sodium acetate is used in combination with acetic acid as a bacteriostatic active ingredient, even if the formulation of the bacteriostatic active ingredient falls within the range disclosed in Patent Document 1, it was confirmed that if the blending ratio of acetic acid to sodium acetate is not appropriate (Comparative Example 3) or if the blending ratio of acetic acid is low (Comparative Examples 4 and 5), a sufficient bacteriostatic effect cannot be obtained even if a good flavor of the hamburger can be obtained.

[0069] Furthermore, even when sodium acetate is used in combination with acetic acid as a bacteriostatic active ingredient, if the blending ratio of acetic acid to sodium acetate is not appropriate, it was confirmed that even if a good flavor of the hamburger steak can be obtained, a sufficient bacteriostatic effect cannot be obtained (Comparative Examples 6 and 7).

[0070] On the other hand, in the cooked hamburger steaks in which sodium acetate was used in combination with acetic acid as a bacteriostatic active ingredient (the ratio of acetic acid to sodium acetate was 1:1.9 to 2.9 (acetic acid:sodium acetate)), it was confirmed that the good flavor of the hamburger steak was felt and sufficient bacteriostatic effect was obtained (Examples 1 to 4). [Example]

[0071] 1. Evaluation method for bacteriostatic effect Lactic acid bacteria (Leuconostoc mesenteroides (NBRC 100496)) was used as a bacteriostatic indicator strain.

[0072] The ingredients are listed in Table 3 below. Walleye pollack surimi was partially thawed and ground five times for 15 seconds using a food processor. The bacteriostatic ingredients listed in Table 4 below were dissolved in cold water and added, followed by grounding three times for 15 seconds using a food processor. Salt was then added, followed by grounding five times for 15 seconds using a food processor. The remaining ingredients listed in Table 3 below were added, followed by grounding three times for 15 seconds using a food processor. Each was divided into 20g portions, molded, and fried in a fryer (170°C x 3 minutes). After cooling at room temperature, the contents were aseptically collected in stomacher bags (10 bags x 100 CFU / g). The lactic acid bacteria listed above were inoculated into the stomacher bags (inoculation amount: 10 CFU / g to 100 CFU / g), and cultured at 10°C for 0 and 168 hours. The viable bacterial count was measured after storage. Then, the remaining samples were subjected to pH measurement and sensory testing. Commercially available food additive-grade glycine was used, and commercially available food additive-grade acetic acid, powdered acetic acid (40% acetic acid, 60% sodium acetate), and sodium acetate were mixed in the ratios shown in the table. KiOuntrime-CsG (Ceti Co., Ltd.) was used as chitosan. A commercially available shelf life extender containing sodium acetate, an organic acid, and glycine was used as a comparative example. The amount of each bacteriostatic active ingredient is shown as a proportion of the total amount of cooked satsumaage (sample) to which the bacteriostatic active ingredient and lactic acid bacteria have been added, taken as 100% by mass.

[0073] After incubation, 180 mL of sterile saline was added to the stomacher bag containing the sample, and the stomacher was stomached for 60 seconds. This was used as the sample suspension, and after serial dilutions with sterile saline as necessary, the total viable bacterial count was measured using the pour plate method (incubated at 35°C for 48 hours) on standard agar medium. 1 mL of sample suspension was added per petri dish. The measurement results are shown as an average (n=3), but the sample at time 0, which corresponds to the initial stage of storage, was evaluated using n=1.

[0074] The bacteriostatic effect was expressed as the common logarithm of the value obtained by dividing the number of viable bacteria in the satsumaage without the addition of bacteriostatic active ingredients (B) by the number of viable bacteria in the satsumaage with the addition of bacteriostatic active ingredients (C) at each incubation time, as shown in the formula below. Bacteriostatic effect = log(B) / (C)

[0075] If the obtained value was 1.5 or more, it was evaluated as "◯" indicating that there was an effective bacteriostatic effect, and if it was less than 1.5, it was evaluated as "×" indicating that there was no effective bacteriostatic effect.

[0076] 2. Sensory test of taste The taste of cooked satsuma-age (cooled to room temperature) with a predetermined pH value and the bacteriostatic active ingredient added in each of the above formulations was evaluated by three trained panelists. The taste was evaluated on a scale of 1 to 5, with the satsuma-age of Comparative Example 8 (containing a commercially available shelf life extender) being given a score of 3 (denoted as "Good"), more preferable ones being given a score of 4 to 5 (denoted as "Excellent"), and less preferable ones being given a score of 1 to 2 (denoted as "Poor").

[0077] 3.Results The formulations of the above bacteriostatic active ingredients, the pH value (25°C) of the cooked satsumaage, the evaluation results of the bacteriostatic effect, and the results of the taste sensory test are shown in Table 4 below.

[0078] [Table 3]

[0079] [Table 4]

[0080] Patent Document 1 discloses a bacteriostatic agent for prepared foods, which is characterized by containing three active ingredients, glycine, acetic acid or sodium acetate, and chitosan, and is adjusted to a pH of 5.6 to 6.0. However, the document states that the above three ingredients do not provide sufficient bacteriostatic activity when the pH exceeds 6.0. However, it was confirmed that cooked satsumaage (fish cakes) containing chitosan, acetic acid, and sodium acetate as active bacteriostatic ingredients (a blending ratio of acetic acid to sodium acetate of 1:1.9 to 2.9) at a pH of about 6.3 retained the pleasant flavor of satsumaage and provided sufficient bacteriostatic activity (Examples 5 and 6).

[0081] On the other hand, it was confirmed that even if commercially available general shelf life extenders could provide a good flavor to the satsumaage, they did not provide a sufficient bacteriostatic effect (Comparative Example 8).

[0082] The above results show that processed foods with a specified pH value, to which acetic acid and sodium acetate are added in a specified ratio together with chitosan as bacteriostatic active ingredients, not only retain the good flavor inherent to the processed food, but also provide sufficient bacteriostatic effects.

Claims

1. A powder bacteriostatic agent for processed foods, comprising acetic acid, sodium acetate, and chitosan, A bacteriostatic agent comprising sodium acetate in a mass ratio to acetic acid of greater than 1:1.5 and less than 6.7 (acetic acid:sodium acetate).

2. The bacteriostatic agent according to claim 1, comprising sodium acetate in a mass ratio of 1:1.9 to 2.9 (acetic acid:sodium acetate) relative to acetic acid.

3. The bacteriostatic agent according to claim 1, characterized in that the composition ratio for adding to food is 0.1 to 0.2 mass% of acetic acid, 0.2 to 0.5 mass% of sodium acetate, and 0.05 to 0.12 mass% of chitosan.

4. The bacteriostatic agent according to claim 1, wherein the processed food is a meat product or a processed seafood product.

5. The bacteriostatic agent of claim 1 , further comprising glycine.

6. The bacteriostatic agent according to claim 5, characterized in that the composition ratio is such that glycine is contained in a food product at a ratio of 0.1 to 0.22% by mass.

7. A processed food containing acetic acid, sodium acetate, and chitosan as bacteriostatic active ingredients, A processed food containing sodium acetate in a mass ratio relative to acetic acid of more than 1.5 and less than 6.7 (acetic acid:sodium acetate), and adjusted to a pH of 5.5 to 6.

5.

8. 8. The processed food according to claim 7, wherein the pH is adjusted to 5.5 to 5.

8.

9. The processed food according to claim 7, comprising sodium acetate in a mass ratio of 1:1.9 to 2.9 (acetic acid:sodium acetate) relative to acetic acid.

10. 8. The processed food according to claim 7, comprising 0.1 to 0.2% by mass of acetic acid, 0.2 to 0.5% by mass of sodium acetate, and 0.05 to 0.12% by mass of chitosan.

11. The processed food according to claim 7, which is a meat product or a processed seafood product.

12. The processed food according to claim 7, further comprising glycine.

13. The processed food according to claim 12, containing glycine in an amount of 0.1 to 0.22% by mass.

14. A method for producing a processed food, comprising adding acetic acid, sodium acetate, and chitosan as bacteriostatic active ingredients to the processed food, and adjusting the pH to a range of 5.5 to 6.5, The method of manufacturing the present invention comprises adding sodium acetate to acetic acid in a mass ratio of more than 1:1.5 and less than 6.7 (acetic acid:sodium acetate).

15. The method according to claim 14, wherein the pH is adjusted to a range of 5.5 to 5.

8.

16. The method according to claim 14, wherein sodium acetate is added to acetic acid in a mass ratio of 1:1.9 to 2.9 (acetic acid:sodium acetate).

17. The method according to claim 14, wherein acetic acid is added in an amount of 0.1 to 0.2% by mass, sodium acetate in an amount of 0.2 to 0.5% by mass, and chitosan in an amount of 0.05 to 0.12% by mass.

18. The method according to claim 14, wherein the processed food is a meat product or a processed seafood product.

19. The method according to claim 14, further comprising adding glycine to the processed food.

20. The method according to claim 19, wherein glycine is added in an amount of 0.1 to 0.22% by mass.

21. A method for inhibiting microbial growth in processed foods, comprising adding acetic acid, sodium acetate, and chitosan as bacteriostatic active ingredients to the processed foods and adjusting the pH to a range of 5.5 to 6.5, The method of claim 1, wherein sodium acetate is added to acetic acid in a mass ratio of greater than 1:1.5 and less than 6.7 (acetic acid:sodium acetate).

22. The method according to claim 21, wherein the pH is adjusted to a range of 5.5 to 5.

8.

23. 22. The method according to claim 21, wherein sodium acetate is added to acetic acid in a mass ratio of 1:1.9 to 2.9 (acetic acid:sodium acetate).

24. The method according to claim 21, wherein acetic acid is added in an amount of 0.1 to 0.2% by mass, sodium acetate in an amount of 0.2 to 0.5% by mass, and chitosan in an amount of 0.05 to 0.12% by mass.

25. 22. The method of claim 21, wherein the processed foods are meat products and seafood products.

26. 22. The method of claim 21, further comprising adding glycine to the processed food.

27. The method according to claim 26, wherein glycine is added in an amount of 0.1 to 0.22% by mass.

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