Milk component-containing beverage and method for producing same

Abstract

The present disclosure provides: a milk component-containing beverage which has a bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria; and a method for producing the milk component-containing beverage. This milk component-containing beverage contains sorbitan palmitate ester, wherein the content ratio of the sorbitan palmitate ester is 0.0015 part by mass or more per 1 part by mass of milk solid content in the milk component-containing beverage.

Description

Dairy beverage and its manufacturing method

[0001] The present disclosure relates to a dairy beverage and a method for producing the same. More specifically, the present disclosure relates to a dairy beverage having bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria and a method for producing the same. The present disclosure also relates to an emulsion stabilizer for dairy beverages, more specifically, an emulsion stabilizer having bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria.

[0002] Known dairy beverages widely available on the Japanese market include coffee beverages containing milk, black tea beverages containing milk, cocoa beverages containing milk, and matcha beverages containing milk. These dairy beverages are filled into pressure-resistant containers, such as retort cans, and then subjected to retort sterilization at approximately 120°C for 20 to 40 minutes before being distributed to the market in order to kill bacteria that cause spoilage or spoilage. However, some highly heat-resistant anaerobic heat-resistant spore-forming bacteria remain viable even after heat sterilization. When the beverages are sold heated in a hot vending machine or heated vending machine, the anaerobic heat-resistant spore-forming bacteria may germinate and multiply, resulting in spoilage or deterioration.

[0003] To kill such anaerobic heat-resistant spore-forming bacteria, methods include increasing the sterilization temperature or lengthening the sterilization time during the manufacturing process, but these methods adversely affect the flavor and physical and chemical properties of the dairy beverage, significantly reducing the quality of the dairy beverage.

[0004] Another known method is to add a sucrose fatty acid ester to suppress the growth of anaerobic heat-resistant spore-forming bacteria and prevent spoilage. Patent Document 1 (Patent Document 1) proposes a method for stably dispersing oils and fats in oil-containing beverages, such as milk coffee and cocoa, while suppressing spoilage caused by heat-resistant flat sour bacteria. This method involves the combined use of a sucrose fatty acid ester with an HLB of 13 or more and an organic acid monoglyceride. Patent Document 1 (Patent Document 1) describes that if the proportion of sucrose fatty acid ester in the beverage is less than 0.05% by mass, the effect of preventing spoilage caused by heat-resistant flat sour bacteria is insufficient, while if the proportion exceeds 0.3% by mass, the bitterness of the sucrose fatty acid ester tends to impair the flavor of the beverage. It also describes that if a sucrose fatty acid ester with a low HLB value is used, the effect of preventing spoilage caused by heat-resistant flat sour bacteria is not obtained. It is also described that when sorbitan monostearate (sorbitan stearic acid monoester) is used in combination with a sucrose fatty acid ester instead of an organic acid monoglyceride, the oil dispersion stabilizing effect is reduced, and release of oil (creaming, oil-off) occurs during long-term storage.

[0005] Furthermore, Patent Document 2 proposes a method of adding 0.0001 to 1% of an antibacterial emulsifier such as sucrose fatty acid ester, polyglycerol fatty acid ester, monoglycerol ester, lecithin, or enzyme-modified lecithin as a method for improving the deterioration of beverages due to the persistence of mesophilic spore-forming bacteria, which is a problem in the sterilization process used in the production of PET bottled beverages. However, Patent Document 2 also describes that sorbitan stearic acid monoester, a sorbitan fatty acid ester, has no antibacterial activity against B. coagulans spores (Table 6).

[0006] Furthermore, Patent Document 3 proposes a method of adding 0.01 to 1 wt % of a sorbitan fatty acid ester, which is a saturated fatty acid having 12 or 14 carbon atoms, to the entire beverage in order to suppress spoilage caused by the germination and proliferation of anaerobic heat-resistant bacterial spores in a sealed container. Patent Document 3 describes that a sorbitan fatty acid ester having a fatty acid having 12 or 14 carbon atoms has a stronger inhibitory effect on the germination and proliferation of anaerobic heat-resistant bacterial spores than sucrose fatty acid esters, polyglycerin fatty acid esters, etc., and has less effect on the taste of the beverage.

[0007] Furthermore, Patent Document 4 proposes a method of adding lysolecithin and an organic acid monoglyceride as a method for producing a dairy-containing coffee beverage that inhibits the germination and proliferation of heat-resistant bacterial spores during long-term storage at high temperatures and has good emulsion stability. Patent Document 4 describes that no antibacterial effect can be obtained even when sorbitan monostearate is used in combination with lysolecithin instead of an organic acid monoglyceride.

[0008] Furthermore, Patent Document 5 proposes an emulsion stabilizer for dairy beverages made from milk and dairy products, such as coffee milk beverages, milk tea, and cocoa beverages, which contains 6 to 16 wt % of sucrose fatty acid ester, 29 to 69 wt % of glycerin monofatty acid ester, 9 to 21 wt % of sorbitan fatty acid ester, 8 to 28 wt % of organic acid monoglyceride, and 3 to 7 wt % of sodium caseinate, and adjusts the pH value of the 0.4% aqueous solution to 5 to 9. It describes that such an emulsifier has good storage stability and can be used stably without requiring a special stirring device when dissolved by heating. However, there is no description of the antibacterial effect of the emulsion stabilizer.

[0009] JP 2-16959 JP 6-261718 JP 6-105669 JP 7-123956 JP 2002-142670

[0010] An object of the present disclosure is to provide a dairy beverage and a method for producing the same. More specifically, an object of the present disclosure is to provide a dairy beverage having bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria and a method for producing the same.

[0011] Another object of the present disclosure is to provide an emulsion stabilizer for dairy beverages. More specifically, an object of the present disclosure is to provide an emulsion stabilizer used to impart bacteriostasis against anaerobic heat-resistant spore-forming bacteria to dairy beverages.

[0012] Furthermore, an object of the present disclosure is to provide a method for imparting bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria to a dairy-containing beverage.

[0013] As a result of extensive research to solve the above-mentioned problems, the present inventors have confirmed that blending a dairy beverage with sorbitan palmitate at a ratio of 0.0015 parts by mass or more per part by mass of milk solids in the dairy beverage effectively inhibits the growth of anaerobic heat-resistant spore-forming bacteria in the beverage (bacteriostatic effect), and that the bacteriostatic effect of sorbitan palmitate is significantly greater than that of sucrose fatty acid esters or other sorbitan fatty acid esters, which have previously been known to have bacteriostatic effects. Furthermore, the present inventors have found that combining a sucrose fatty acid ester with a sorbitan palmitate can reduce the amount of sucrose fatty acid ester used and minimize the impact of the sucrose fatty acid ester on the flavor of the dairy beverage while still exerting an effective bacteriostatic effect. The present invention was completed based on these findings and has the following embodiments.

[0014] (I) Dairy Beverages (I-1) A dairy beverage containing sorbitan palmitate, wherein the proportion of sorbitan palmitate per part by mass of milk solids in the dairy beverage is 0.0015 parts by mass or more. (I-2) The dairy beverage according to (I-1), wherein the dairy beverage contains 0.5 to 11.5% by mass of milk solids. (I-3) The dairy beverage according to (I-1) or (I-2), wherein the proportion of sorbitan palmitate in 100% by mass of the dairy beverage is 0.001 to 0.5% by mass. (I-4) The dairy beverage according to any of (I-1) to (I-3), further containing a sucrose fatty acid ester. (I-5) A dairy beverage according to (I-4), in which the ratio of sucrose fatty acid ester to 100 parts by mass of sorbitan palmitate is 1 to 300 parts by mass. (I-6) A dairy beverage according to any one of (I-1) to (I-5), which is bacteriostatic against anaerobic heat-resistant spore-forming bacteria. (I-7) A dairy beverage according to any one of (I-1) to (I-6), which is a packaged beverage, preferably a sterilized packaged beverage.

[0015] (II) Methods for producing dairy beverages (II-1) A method for producing a dairy beverage, comprising the step of blending a sorbitan palmitate into a dairy beverage so that the ratio of the sorbitan palmitate per part by mass of milk solids in the dairy beverage is 0.0015 parts by mass or more. (II-2) The method for producing a dairy beverage as described in (II-1), wherein the dairy beverage contains 0.5 to 11.5% by mass of milk solids. (II-3) The method for producing a dairy beverage as described in (II-1) or (II-2), wherein the sorbitan palmitate is blended so that the concentration of the sorbitan palmitate in 100% by mass of the dairy beverage is 0.001 to 0.5% by mass. (II-4) The method for producing a dairy beverage as described in any of (II-1) to (II-3), further comprising the step of blending a sucrose fatty acid ester into the dairy beverage. (II-5) The production method according to (II-4), wherein the ratio of the sucrose fatty acid ester to 100 parts by mass of the sorbitan palmitate is 1 to 300 parts by mass. (II-6) The production method according to any one of (II-1) to (II-5), further comprising a heat sterilization treatment step. (II-7) The production method according to any one of (II-1) to (II-6), which is a production method for a dairy beverage for imparting bacteriostasis against anaerobic heat-resistant spore-forming bacteria to the dairy beverage.

[0016] (III) Method for imparting bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria to a dairy beverage. The production methods (II-1) to (II-6) above can also be rephrased as follows: (III-1) A method for imparting bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria to a dairy beverage, comprising blending a sorbitan palmitate into the dairy beverage so that the ratio of the sorbitan palmitate per part by mass of milk solids in the dairy beverage is 0.0015 parts by mass or more. (III-2) The method described in (III-1), wherein the dairy beverage contains milk solids in a ratio of 0.5 to 11.5% by mass. (III-3) The method described in (III-1) or (III-2), wherein a sorbitan palmitate is blended so that the concentration of the sorbitan palmitate in 100% by mass of the dairy beverage is 0.001 to 0.5% by mass. (III-4) The method according to any one of (III-1) to (III-3), further comprising blending a sucrose fatty acid ester into the dairy beverage. (III-5) The method according to (III-4), wherein the ratio of the sucrose fatty acid ester to 100 parts by mass of the sorbitan palmitate is 1 to 300 parts by mass.

[0017] (IV) Emulsion stabilizer for dairy beverages (IV-1) An emulsion stabilizer for dairy beverages containing sorbitan palmitate as an active ingredient, wherein the emulsion stabilizer is used so that the ratio of sorbitan palmitate per part by mass of milk solids in the dairy beverage is 0.0015 parts by mass or more. (IV-2) The emulsion stabilizer for dairy beverages described in (IV-1), which is a formulation used to impart bacteriostasis against anaerobic heat-resistant spore-forming bacteria to a dairy beverage. (IV-3) The emulsion stabilizer for dairy beverages described in (IV-1) or (IV-2), wherein the dairy beverage contains milk solids in a ratio of 0.5 to 11.5% by mass. (IV-4) An emulsion stabilizer for dairy beverages according to any one of (IV-1) to (IV-3), which is used in the production process of a dairy beverage so that the concentration of sorbitan palmitate in 100% by mass of the dairy beverage is 0.001 to 0.5% by mass. (IV-5) An emulsion stabilizer for dairy beverages according to any one of (IV-1) to (IV-4), which further contains a sucrose fatty acid ester in the dairy beverage. (IV-6) An emulsion stabilizer for dairy beverages according to (IV-5), in which the ratio of the sucrose fatty acid ester to 100 parts by mass of sorbitan palmitate is 1 to 300 parts by mass.

[0018] According to the present disclosure, it is possible to provide a dairy beverage having a high growth inhibitory effect (bacteriostatic effect) on anaerobic heat-resistant spore-forming bacteria, and a method for producing the same. In particular, it is possible to provide a heat-sterilized dairy beverage having a high effect of inhibiting the growth of anaerobic heat-resistant spore-forming bacteria that may remain even after heat sterilization, and having good storage stability, and a method for producing the same.

[0019] Furthermore, the present disclosure can provide a method for imparting bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria to a dairy beverage while minimizing the impact on the flavor of the dairy beverage.

[0020] Furthermore, the present disclosure provides emulsion stabilizing agents for dairy beverages that can be used to impart bacteriostasis to dairy beverages against anaerobic heat-resistant spore-forming bacteria.

[0021] (I) Dairy beverages The dairy beverages covered by the present disclosure are beverages (dairy beverages) that contain at least milk solids as a milk component, but are not milk itself, such as raw milk, cow's milk, special milk, adjusted milk, low-fat milk, and non-fat milk.

[0022] The target milk is milk from livestock such as cows (dairy cows such as Holstein, Jersey, and Brown Swiss), sheep, and goats, and preferably milk derived from dairy cows (hereinafter referred to as "milk derived from dairy cows").

[0023] Examples of milk solids include milk fat and non-fat milk solids. Non-fat milk solids include milk-derived proteins, carbohydrates, minerals, and vitamins. The beverages targeted by the present invention contain at least one milk solid selected from the milk fat and non-fat milk solids. Preferably, the beverage contains milk fat and non-fat milk solids as the milk solids, and more preferably, the beverage contains cow's milk itself as the milk component. Holstein-derived raw milk is composed of 87.7% water by mass and 12.3% milk solids by mass, with the milk solids consisting of milk fat (3.7% by mass) and non-fat milk solids (8.6% by mass). The non-fat milk solids also contain protein (3.2% by mass), carbohydrates (4.7% by mass), minerals such as calcium (0.7% by mass), and vitamins (see Chapter 2 (Data), Food No. 13002, of the Standard Tables of Food Composition in Japan, 8th Edition, published by the Ministry of Education, Culture, Sports, Science and Technology of Japan).

[0024] When raw milk from Holstein cows is used as the milk component, the milk solids content in the dairy beverage can be calculated using the following formula: [Formula] Milk solids content (% by mass) in dairy beverage = 12.3 (amount of milk solids in raw milk) x blend amount of raw milk (% by mass).

[0025] Furthermore, when raw milk derived from Holstein cows is used as the milk component, the milk solids (total amount) in the beverage containing the milk component can also be calculated from the amount of milk fat and / or milk protein in the beverage based on the composition ratio of the milk solids in cow's milk described above.

[0026] Furthermore, when milk other than Holstein-derived raw milk is used as the dairy ingredient in a dairy beverage, the formula can be calculated in the same way by substituting the milk solids content of the milk into the value "12.3" in the formula. This value can be derived from Chapter 2 (Data) of the Standard Tables of Food Composition in Japan, 8th Edition (see Food Code 13000). For example, Jersey-derived raw milk is composed of 85.5% water by mass and 14.5% milk solids by mass, with the milk solids consisting of milk fat (3.7% by mass) and non-fat milk solids (9.3% by mass). The non-fat milk solids also contain protein (3.9% by mass), carbohydrates (4.7% by mass), minerals such as calcium (0.7% by mass), and vitamins (Food Code 13001). Similarly, regular cow's milk is composed of 87.4% water by mass and 12.6% milk solids by mass, which consist of milk fat (3.8% by mass) and non-fat milk solids (8.8% by mass). The non-fat milk solids also contain protein (3.3% by mass), carbohydrates (4.8% by mass), minerals such as calcium (0.7% by mass), and vitamins (food code 13003).

[0027] The dairy beverage may be any beverage containing the dairy component, and includes, but is not limited to, dairy coffee beverages such as milk coffee, coffee milk beverage, cafe au lait, cafe latte, and cappuccino; dairy black tea beverages such as milk tea (black tea); dairy matcha or green tea beverages such as matcha milk and green tea milk; dairy fruit juice beverages; dairy cocoa beverages; dairy chocolate drinks; milkshakes, etc. Although not limited to, preferred beverages are those produced using milk derived from dairy cows as one of the ingredients. More preferred are dairy coffee beverages.

[0028] Suitable dairy beverages include beverages with a milk solids content of 0.5 to 11.5% by mass, preferably 0.5 to 10.0% by mass, and more preferably 0.6 to 9.0% by mass.

[0029] The pH range of the dairy beverage is not limited, but can usually be selected from the range of pH 5.0 to 8.0, preferably pH 5.5 to 7.5, and more preferably pH 5.8 to 7.2.

[0030] An example of a component (referred to herein for convenience as a "bacteriostatic component") used to produce a dairy beverage having a bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria is (A) sorbitan palmitate ester (hereinafter also simply referred to as "component A"). Component A can be used alone as a bacteriostatic component, or can be used in combination with (B) sucrose fatty acid ester (hereinafter also simply referred to as "component B"). It is also known that polyglycerin fatty acid esters, monoglycerin esters, lecithin, enzyme-treated lecithin, and the like also have antibacterial properties. However, the dairy beverage of the present disclosure has little need for these components, and in fact it is preferable not to use them.

[0031] The sorbitan palmitate used in the present invention is an ester obtained by reacting sorbit with a saturated fatty acid having 16 carbon atoms in a conventional manner. The ester includes monoesters, diesters, and triesters. The monoester is preferred.

[0032] The sucrose fatty acid ester used in the present invention is an esterification product of sucrose and a fatty acid. The chain length of the fatty acid is 12 to 22 carbon atoms, preferably 12 to 20 carbon atoms, more preferably 14 to 18 carbon atoms, and particularly preferably 16 carbon atoms. Saturated fatty acids are desirable. The degree of esterification can include mono-, di-, and triesters, with monoesters being preferred. The fatty acid composition and mono-, di-, and triesters may be either single or mixed. The fatty acid composition preferably contains 50% or more of saturated fatty acids having 14 to 18 carbon atoms, and 50% or more, preferably 60% or more, and more preferably 70% or more of monoesters. The HLB of the sucrose fatty acid ester is not particularly limited, but is preferably in the range of 10 to 20, more preferably 14 to 18, and particularly preferably 16.

[0033] (When component A is used as a bacteriostatic component without being used in combination with component B) When component A is used as a bacteriostatic component without being used in combination with component B, the blending ratio of component A to the dairy beverage can be 0.0015 parts by mass or more per part by mass of milk solids in the dairy beverage. Examples of lower limits include 0.00155 parts by mass or more, 0.002 parts by mass or more, 0.003 parts by mass or more, 0.004 parts by mass or more, 0.005 parts by mass or more, 0.006 parts by mass or more, and 0.007 parts by mass or more. The upper limit is not limited as long as it does not impede the effects of the present disclosure, but is preferably 0.3 parts by mass or less per part by mass of milk solids in the dairy beverage. Examples of upper limits include 0.25 parts by mass or less, 0.2 parts by mass or less, 0.18 parts by mass or less, 0.16 parts by mass or less, 0.15 parts by mass or less, 0.13 parts by mass or less, and 0.1 parts by mass or less. The blending ratio can be set by arbitrarily combining these lower and upper limits.

[0034]

[0035] The milk solids content in a dairy beverage can be determined from the total amount of milk fat and non-fat milk solids in the dairy ingredients used as raw materials for producing the dairy beverage.

[0036] The proportion of component A in 100% by mass of the dairy beverage is not particularly limited as long as the blending ratio per part by mass of the milk solids in the dairy beverage is within the above-mentioned range, but can be in the range of 0.001 to 0.5% by mass, preferably 0.004 to 0.4% by mass, and more preferably 0.006 to 0.3% by mass.

[0037] (When Component A and Component B are Used in Combination as Bacteriostatic Components) When Component A and Component B are used in combination as bacteriostatic components, the proportion of Component A in the dairy beverage is not particularly limited as long as it is within the above-mentioned range, but the total amount of Component A and Component B in the dairy beverage can be adjusted to a ratio of 0.0015 parts by mass or more per part by mass of milk solids in the beverage. Examples of lower limits include 0.00155 parts by mass or more, 0.002 parts by mass or more, 0.003 parts by mass or more, 0.004 parts by mass or more, 0.005 parts by mass or more, 0.0055 parts by mass or more, 0.006 parts by mass or more, 0.0065 parts by mass or more, 0.007 parts by mass or more, 0.0075 parts by mass or more, 0.008 parts by mass or more, and 0.0085 parts by mass or more. The upper limit is not limited as long as it does not interfere with the effects of the present invention, but is preferably 0.5 parts by mass or less per part by mass of milk solids in the beverage. Examples of the upper limit include 0.4 parts by mass or less, 0.3 parts by mass or less, 0.2 parts by mass or less, 0.1 parts by mass or less, 0.08 parts by mass or less, 0.06 parts by mass or less, and 0.05 parts by mass or less. The blending ratio can be set by arbitrarily combining these lower and upper limits.

[0038]

[0039] The ratio of the combined use of component A and component B can be in the range of 1 to 300 parts by mass of component B per 100 parts by mass of component A. Preferably, the ratio of component B is 1 to 250 parts by mass, and more preferably 10 to 200 parts by mass, per 100 parts by mass of component A.

[0040] The total amount of component A and component B in 100% by mass of the dairy beverage is not particularly limited as long as the total amount of component A and component B per part by mass of the milk solids in the dairy beverage is within the above range, but can be in the range of 0.005 to 0.5% by mass, preferably 0.0055 to 0.4% by mass, and more preferably 0.006 to 0.3% by mass.

[0041] The total amount of component B in 100% by mass of the dairy beverage is not limited as long as the above ratio is satisfied, but may be in the range of 0.00005 to 0.375% by mass, preferably 0.000055 to 0.3% by mass, and more preferably 0.00006 to 0.1% by mass.

[0042] According to the present invention, by using the above-described bacteriostatic component in the above-described ratio in a dairy beverage, a dairy beverage having bacteriostatic properties against anaerobic heat-resistant spore-forming bacteria can be prepared. This dairy beverage inhibits the germination and proliferation of anaerobic heat-resistant spore-forming bacteria, which are problematic in sealed-container beverages, thereby preventing spoilage of the sealed-container beverage. More preferably, according to the present invention, the germination and proliferation of anaerobic heat-resistant spore-forming bacteria, which remain problematic even in sealed-container beverages that have been heat-sterilized, can be inhibited, preventing spoilage of the sealed-container beverage. Although not limited to, Thermoanaerobacter mathranii is one example of the anaerobic heat-resistant spore-forming bacteria that are generally problematic in sealed-container beverages. The presence or absence of bacteriostatic properties against anaerobic heat-resistant spore-forming bacteria (the presence or absence of a bacteriostatic effect) can be determined based on the "bacteriostatic test" described in the Examples section below.

[0043] Examples of sealed containers that can be used for the beverage of the present invention include cans, bottles, PET bottles, paper packs, laminate packs, etc., but heat-resistant and / or retort-resistant cans or bottles are preferred, and retort cans are more preferred.

[0044] (II) Method for Producing a Dairy Beverage The present disclosure relates to a method for producing a dairy beverage. The method can be suitably used to impart bacteriostasis against anaerobic heat-resistant spore-forming bacteria to a dairy beverage. The method includes blending a sorbitan palmitate ester (component A) into the dairy beverage at a ratio of 0.0015 parts by mass or more per part by mass of milk solids in the dairy beverage. This method can be carried out by blending component A alone as the component imparting bacteriostasis, or by blending a sucrose fatty acid ester (component B) in addition to component A. Furthermore, in this method, there is little need to blend other bacteriostatic components known to have antibacterial activity, and it is preferable not to use them. Examples of such bacteriostatic components include the aforementioned polyglycerol fatty acid esters, monoglycerol esters, lecithin, and enzyme-treated lecithin.

[0045] The dairy beverages, anaerobic heat-resistant spore-forming bacteria, sorbitan palmitate ester (component A) and sucrose fatty acid ester (component B) to be blended in the dairy beverages that are the subject of this disclosure, and their blending ratios, etc. are as explained in section (I) above, and the descriptions therein can be used by reference in this section.

[0046] The dairy beverages targeted by the present disclosure are preferably beverages in sealed containers, more preferably beverages in sealed containers that have been heat-sterilized. Therefore, the manufacturing method of the present disclosure includes a step of heat-sterilizing a dairy beverage containing component A or a blend of components A and B. The heat-sterilization may be performed before or after filling into a container, and the order is not particularly limited. An example of the former method is, but is not limited to, a method in which a prepared dairy beverage is heat-sterilized and then filled into a container that has been sterilized under aseptic conditions. An example of the latter method is, but is not limited to, a method in which a prepared dairy beverage is filled into a heat-resistant and retort-resistant container and then heat-sterilized.

[0047] The heat sterilization treatment may be any sterilization treatment commonly used in beverage production. For example, the sterilization conditions and sterilization equipment are not particularly limited, and commonly used sterilization treatments and sterilization conditions such as boiling sterilization, retort sterilization, UHT sterilization (e.g., indirect methods such as plate sterilization and tubular sterilization, and direct methods such as steam injection sterilization), and autoclave sterilization can be widely used. A preferred embodiment is pressurized heat treatment at 121°C for 20 minutes or more, preferably 30 minutes or more or 40 minutes or more. If the pressurized heat treatment time is too long, it may have a negative impact on the flavor, physical, and chemical properties of the dairy beverage. For this reason, the heat treatment time at 121°C is preferably 60 minutes or less, preferably 50 minutes or less.

[0048] (III) Method for imparting bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria to a dairy beverage The present disclosure relates to a method for imparting bacteriostatic activity against anaerobic heat-resistant spore-forming bacteria to a dairy beverage. The method of the present disclosure can be carried out by blending a sorbitan palmitate ester (component A) into the dairy beverage in a proportion of 0.0015 parts by mass or more per part by mass of milk solids in the dairy beverage during the production process of the dairy beverage. Furthermore, this method can be carried out by blending component A alone as the component that imparts bacteriostatic activity, or by blending a sucrose fatty acid ester (component B) in addition to component A.

[0049] The dairy beverages, anaerobic heat-resistant spore-forming bacteria, sorbitan palmitate ester (component A) and sucrose fatty acid ester (component B) to be blended in the dairy beverages that are the subject of this disclosure, and their blending ratios, etc. are as explained in section (I) above, and the descriptions therein can be used by reference in this section.

[0050] (IV) Emulsion stabilizer for dairy beverages The present disclosure relates to an emulsion stabilizer for dairy beverages. The emulsion stabilizer of the present disclosure is characterized by containing sorbitan palmitate (Component A) as an active ingredient for emulsion stabilization. When used in a dairy beverage such that the ratio of Component A per part by mass of milk solids in the dairy beverage is 0.0015 parts by mass or more, the emulsion stabilizer exerts an excellent bacteriostatic effect on the dairy beverage. Therefore, in this usage mode, the emulsion stabilizer has the effect (use) of both being an emulsion stabilizer and a bacteriostatic agent.

[0051] The present emulsion stabilizer may contain the component A alone as an active ingredient for emulsion stabilization or as an ingredient having both emulsion stabilizing and bacteriostatic effects, but may also contain a sucrose fatty acid ester (component B) in addition to component A.

[0052] The present emulsion stabilizer may contain Component A in the range of 1% by mass to 100% by mass, or may consist of 100% by mass of Component A. Furthermore, when Component A and Component B are contained, the emulsion stabilizer may contain them in a total amount in the range of 2% by mass to 100% by mass, or may consist of 100% by mass of Component A and Component B.

[0053] The form of the emulsion stabilizer is not particularly limited and can be appropriately selected from liquid (liquid preparation), emulsified (emulsion), and solid (powder, granules, tablet) forms. Depending on the form, various excipients, diluents, binders, lubricants, etc. can be contained.

[0054] The dairy beverages covered by the present disclosure; the anaerobic heat-resistant spore-forming bacteria; the sorbitan palmitate ester (component A) and sucrose fatty acid ester (component B) blended in the present emulsion stabilizer, and their blending ratios; and the usage ratios of the dairy beverages (blending ratios of component A and component B) are as explained in section (I) above, and the descriptions therein can be used by reference in this section.

[0055] As described above, in this specification, the terms "comprise" and "contain" encompass the meanings of "consist of" and "consist essentially of."

[0056] The present invention will be described below using experimental examples to aid in understanding the configuration and effects of the present invention. However, the present invention is not limited by these experimental examples. Unless otherwise specified, the following experiments were carried out at room temperature (25±5°C) and atmospheric pressure. Unless otherwise specified, "%" and "parts" in the following descriptions mean "% by mass" and "parts by mass," respectively.

[0057] The materials used in the following experimental examples and examples are as follows: Sorbitan palmitate: 100% sorbitan palmitate monoester, product name Homogen (registered trademark) 3369 (manufactured by San-Ei Gen F.F.I., Inc.). Sorbitan laurate: 100% sorbitan laurate monoester, Homogen (registered trademark) 3367 (manufactured by San-Ei Gen F.F.I., Inc.). Sorbitan myristate: 100% sorbitan myristate monoester, Homogen (registered trademark) 3368 (manufactured by San-Ei Gen F.F.I., Inc.). Sorbitan stearate: 100% sorbitan stearate monoester, Homogen (registered trademark) 3370 (manufactured by San-Ei Gen F.F.I., Inc.). Sucrose fatty acid ester: Ryoto Sugar Ester P-1670 (sucrose palmitate), HLB approximately 16, bound fatty acid purity (approximately 80), monoester content (approximately 80%), di- and tri-polyester content (approximately 20%) (manufactured by Mitsubishi Chemical Corporation). Anaerobic heat-resistant spore-forming bacterium 5901: Thermoanaerobacter mathranii (obtained from the Japan Canned, Bottled, and Retort Food Association). Modified TGC medium: TGC medium "Nissui" (manufactured by Nissui Pharmaceutical Co., Ltd.) with the agar content increased from 0.07% to 0.15%. SS liquid medium: 10 g of bactosyton and 0.5 g of anhydrous sodium sulfite were dissolved in 1000 mL of distilled water, to which a 9:1 mixture (by mass) of sterilized dry earth and sterilized calcium carbonate was added, followed by sterilization at 121°C for 20 minutes.

[0058] The evaluation methods used in the following experimental examples are as follows: (1) Bacteriostasis test The prepared coffee beverage containing dairy ingredients (hereinafter referred to as "beverage") was placed in a medium bottle and degassed by boiling in hot water at 100°C for 20 minutes, and then cooled to room temperature. A spore solution of anaerobic heat-resistant spore-forming bacteria 5901 was added to the cooled beverage until the initial number of bacteria reached 10. ４ The mixture was added with stirring to a level on the order of CFU / g.

[0059] The spore-forming bacteria solution used was prepared by pre-culturing the anaerobic heat-resistant spore-forming bacteria 5901 in modified TGC medium, followed by main culturing in SS liquid medium for spore formation, followed by centrifugation to remove the precipitate.

[0060] Next, 3 ml of the beverage containing the spore-forming bacteria solution was aseptically dispensed into sterilized TDT tubes (hard glass, inner diameter 6 mm) and heat-sealed using a gas burner. These were then heat-sterilized in an oil bath at 124.2°C for a predetermined time (e.g., 5 to 30 minutes), and then cultured in an incubator at 55°C for 4 weeks (n = 5 for each tube).

[0061] After 4 weeks of cultivation, the appearance and pH were compared with those of a blank, which differed only in that no spore-forming solution was added (a beverage cooled after degassing in a hot water bath was sealed in a TDT tube in the same manner as above, heat sterilized, and then cultivated under the same conditions, without adding the spore-forming solution), and the bacteriostatic effect was evaluated.

[0062] In the appearance evaluation, if a difference in appearance from the blank was observed, for example, the culture became cloudy, it was judged to be "spoiled" and judged to be "positive." Even if no difference in appearance from the blank was observed in the appearance evaluation, if the pH was 0.3 or more lower than that of the blank, it was judged to be "positive." If no difference in appearance from the blank was observed in the appearance evaluation and the difference in pH from the blank was less than 0.3, it was judged to be "negative." If all of n = 5 were judged to be negative (0 / 5), it was considered to have a bacteriostatic effect.

[0063] Sterilization times of 5, 10, 12.5, 15, 17.5, 20, and 30 minutes at 124.2°C correspond to sterilization times of 10, 20, 25, 30, 35, 40, and 60 minutes at 121°C, respectively. ０ The value is expressed as the sterilization time at 124.2°C converted to the sterilization time at 121°C (for example, when sterilized at 124.2°C for 5 minutes, it is expressed as "F ０ Similarly, when sterilized at 124.2°C for 10 minutes, 12.5 minutes, 15 minutes, 17.5 minutes, 20 minutes, and 30 minutes, the results are written as "F = 10", respectively. ０ =20", "F ０ =25", "F ０ =30", "F ０ =35", "F ０ =40" and "F ０ =60").

[0064] (2) Confirmation of Initial Bacterial Count The initial bacterial count of anaerobic heat-resistant spore-forming bacteria 5901 added to the prepared dairy-based coffee beverage was confirmed using the following method. 1 ml of the beverage containing the added spore-forming bacteria solution was placed in a sterilized test tube and diluted 10 times with sterilized peptone water. The mixture was heated in a hot water bath at 100°C for 30 minutes to activate the bacteria, then diluted appropriately and inoculated onto modified TGC medium. After anaerobically culturing the medium in an anaerobic culture pouch at 65°C for 1 week, the bacterial count was measured. The resulting bacterial count was multiplied by the dilution factor (total factor) to obtain the initial bacterial count.

[0065] (3) Measurement of pH The pH of the culture was measured using a pH meter (HORIBA Compact pH Meter LAQUAtwin B-71X) after adjusting the temperature of the culture to room temperature.

[0066] Production Example 1 Production of a Coffee Drink Containing a Dairy Component (1) Preparation of Coffee Extract After roasted coffee beans are ground (coarsely ground), a five-fold amount of hot water (80 to 100°C) is added, and the beans are left to steep for 40 minutes, followed by filtration to obtain a coffee extract.

[0067] (2) Preparation of dairy-containing coffee beverage Coffee extract, milk, sugar, emulsifier, baking soda, and water were mixed according to the following recipe, and the pH was adjusted to 7.0. The emulsifier used was prepared in advance by dissolving the emulsifier and a portion of the baking soda in hot water at about 75°C by stirring at 75°C for 5 minutes. After mixing all the ingredients (adjusting the pH to 7.0 with the remaining baking soda), the mixture was heated to 75°C and homogenized (using a two-stage high-pressure homogenizer, first stage at 10 MPa, second stage at 5 MPa), and then filled into retort cans to produce dairy-containing coffee beverages.

[0068] <Formulation> Coffee extract 1.2% (as coffee solids) 注１ Milk Sugar 6.0% (as shown in Tables 3-6, 11-14) Emulsifier Sodium bicarbonate (as shown in Tables 3-6, 11-14) pH adjustment amount (pH 7.0) Water Balance Total 100% 注２

[0069] Note 1: Coffee solids The amount of solids in the coffee extract (coffee solids) (total dissolved solids (TDS)) was determined by measuring the coffee extract with a digital saccharometer (ATAGO PR101α). Measuring the refractive index with a digital saccharometer allows us to determine the concentration of solids dissolved in the coffee extract.

[0070] Note 2: Milk solids in the final dairy coffee beverage The amount of milk solids in the final beverage can be calculated using the following formula: [Formula] Milk solids (mass%) = 12.6 (solids in milk) x milk content (%)

[0071] The dairy coffee beverages filled into retort cans as described above were subjected to retort sterilization at 121°C for 20 minutes and then stored at 55°C for 4 weeks. The dairy coffee beverages prepared by adding only a sucrose fatty acid ester as an emulsifier generated solids over time during storage and had a bitter aftertaste (Comparative Examples 1-3, 2-3, 3-3, 4-3, 9-1, 9-2, 10-1, 10-2, 11-1, 11-2, and 12-1 to 12-4). In contrast, the dairy coffee beverages prepared by adding a sorbitan palmitate as an emulsifier (Examples 1 to 4 and 9 to 12) did not show any effect on physical properties, such as the generation of solids, or on flavor, such as the taste of an emulsifier.

[0072] Production Example 2: Production of a Dairy Beverage According to the following recipe, milk, sugar, an emulsifier, baking soda, and water were mixed and adjusted to a pH of 7.0. The emulsifier used was prepared in advance by dissolving the emulsifier and a portion of the baking soda in hot water at about 75°C by stirring at 75°C for 5 minutes. After mixing all the ingredients (adjusting the pH to 7.0 with the remaining baking soda), the mixture was heated to 75°C and homogenized (using a two-stage high-pressure homogenizer, first stage at 10 MPa, second stage at 5 MPa), and then filled into retort cans to produce a dairy beverage.

[0073] <Formulation> Milk Sugar 6.0% (as shown in Tables 7 to 10) Emulsifier Sodium bicarbonate (as shown in Tables 7 to 10) pH adjustment amount (pH 7.0) Water Remainder Total 100% 前記注２

[0074] The dairy coffee beverages (Tables 5 to 8) filled into retort cans as described above were retort sterilized at 121°C for 20 minutes and then stored for 4 weeks at 55°C. None of these dairy beverages were found to have any effect on the physical properties, such as the formation of solids, or on the flavor, such as the taste of an emulsifier.

[0075] Experimental Example 1: Evaluation of the bacteriostatic effect of sorbitan palmitic acid fatty acid esters (Part 1) Various dairy coffee beverages (before being filled into retort cans) were prepared according to the description of Production Example 1 using the emulsifiers listed in Tables 3 to 6. The prepared dairy coffee beverages were placed in medium bottles and subjected to the bacteriostatic test described above (heat treatment at 124.2°C followed by storage at 55°C for 4 weeks). If all of the samples (n=5) were judged to be negative (0 / 5), it was judged to have a bacteriostatic effect, and if not (1 / 5 to 5 / 5), it was judged to have no bacteriostatic effect.

[0076]

[0077]

[0078]

[0079]

[0080] As shown in Tables 3 to 6, it was confirmed that sorbitan fatty acid monoesters generally have a stronger bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria in dairy-containing coffee beverages than sucrose fatty acid esters. Among sorbitan fatty acid monoesters, sorbitan palmitate in particular was found to have a stronger bacteriostatic effect. In particular, it was confirmed that by incorporating sorbitan palmitate in a ratio of 0.004 part by mass or more per part by mass of milk solids in a dairy-containing coffee beverage, it is possible to impart bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria to the dairy-containing coffee beverage.

[0081] Experimental Example 2: Evaluation of the bacteriostatic effect of sorbitan palmitic acid fatty acid esters (part 2) Various dairy beverages (before being filled into retort cans) were prepared according to the description of Production Example 2 using the emulsifiers listed in Tables 7 to 10. The prepared dairy coffee beverages were placed in medium bottles and subjected to the bacteriostatic test described above (heat treatment at 124.2°C followed by storage at 55°C for 4 weeks). If all of the samples (n=5) were judged to be negative (0 / 5), it was judged to have a bacteriostatic effect, and if not (1 / 5 to 5 / 5), it was judged to have no bacteriostatic effect.

[0082]

[0083]

[0084]

[0085]

[0086] As shown in Tables 7 to 10, it was confirmed that sorbitan palmitate has a high bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria in dairy beverages. In particular, it was confirmed that by blending sorbitan palmitate in a ratio of 0.0015 parts by mass or more per part by mass of milk solids in a dairy beverage, it is possible to effectively impart bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria to the dairy beverage.

[0087] Experimental Example 3: Evaluation of the bacteriostatic effect of a combination of sorbitan palmitate and sucrose fatty acid ester Various dairy coffee beverages (before filling into retort cans) were prepared according to the description of Production Example 1 using the emulsifiers listed in Tables 11 to 16. The prepared dairy coffee beverages were placed in medium bottles and subjected to the bacteriostatic test described above (heat treatment at 124.2°C followed by storage at 55°C for 4 weeks). If all of the five samples (n = 5) were judged to be negative (0 / 5), it was judged to have a bacteriostatic effect, and if not (1 / 5 to 5 / 5), it was judged to have no bacteriostatic effect.

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094] As shown in Tables 11 to 16, it was confirmed that the combined use of sucrose fatty acid ester and sorbitan fatty acid ester can enhance the bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria in dairy beverages, which was previously only weakly effective when sucrose fatty acid ester was used alone. It is known that sucrose fatty acid esters can deteriorate the flavor of beverages depending on the amount used. The results of this experiment demonstrated that by combining sucrose fatty acid ester with sorbitan fatty acid ester, a high bacteriostatic effect can be achieved while reducing the amount of sucrose fatty acid ester used, which may affect flavor depending on the amount used.

[0095] Experimental Example 4: Evaluation of the bacteriostatic effect of sorbitan palmitic acid fatty acid esters (part 3) Various dairy coffee beverages (before being filled into retort cans) were prepared according to the description of Production Example 1 using the emulsifiers listed in Tables 17 to 19. The prepared dairy coffee beverages were placed in medium bottles and subjected to the bacteriostatic test described above (heat treatment at 124.2°C followed by storage at 55°C for 4 weeks). If all of the samples (n=5) were judged to be negative (0 / 5), it was judged to have a bacteriostatic effect, and if not (1 / 5 to 5 / 5), it was judged to have no bacteriostatic effect.

[0096]

[0097]

[0098]

[0099] As shown in Tables 17 to 19, it was confirmed that sorbitan palmitate has a high bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria in dairy beverages. In particular, it was confirmed that by incorporating sorbitan palmitate in a ratio of 0.0015 parts by mass or more per part by mass of milk solids in a dairy beverage, it is possible to effectively impart bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria to the dairy beverage.

[0100] Experimental Example 5: Evaluation of the bacteriostatic effect of sorbitan palmitic acid fatty acid esters (part 4) Various dairy beverages (before being filled into retort cans) were prepared according to the description of Production Example 2 using the emulsifiers listed in Tables 20 to 22. The prepared dairy beverages were placed in medium bottles and subjected to the bacteriostatic test described above (heat treatment at 124.2°C followed by storage at 55°C for 4 weeks). If all of the samples (n=5) were judged to be negative (0 / 5), it was judged to have a bacteriostatic effect, and if not (1 / 5 to 5 / 5), it was judged to have no bacteriostatic effect.

[0101]

[0102]

[0103]

[0104] As shown in Tables 20 to 22, sorbitan palmitate has a high bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria in dairy beverages, and it was confirmed that by incorporating sorbitan palmitate in a ratio of 0.0015 parts by mass or more per part by mass of milk solids in a dairy beverage, it is possible to effectively impart bacteriostatic effect against anaerobic heat-resistant spore-forming bacteria to dairy beverages.

Claims

1. A dairy beverage containing sorbitan palmitate, wherein the ratio of sorbitan palmitate per part by mass of milk solids in the dairy beverage is 0.0015 parts by mass or more.

2. A dairy beverage according to claim 1, wherein the dairy beverage contains 0.5 to 11.5% by mass of milk solids.

3. A dairy beverage according to claim 1 or 2, in which the proportion of sorbitan palmitate in 100% by mass of the dairy beverage is 0.001 to 0.5% by mass.

4. A dairy beverage according to claim 1 or 2, further comprising a sucrose fatty acid ester.

5. A dairy beverage according to claim 4, wherein the ratio of sucrose fatty acid ester to 100 parts by mass of sorbitan palmitate is 1 to 300 parts by mass.

6. A dairy beverage according to claim 1 or 2, characterized in that it has bacteriostatic properties against anaerobic heat-resistant spore-forming bacteria.

7. A method for producing a dairy beverage, comprising a step of blending sorbitan palmitate with a dairy beverage so that the ratio of sorbitan palmitate per 1 mass part of milk solids in the dairy beverage is 0.0015 mass parts or more.

8. The method of claim 7, wherein the dairy beverage contains 0.5 to 11.5% by mass of milk solids.

9. The method of claim 7 or 8, wherein sorbitan palmitate is blended so that its concentration in the dairy beverage (100% by mass) is 0.001 to 0.5% by mass.

10. The method of claim 7 or 8, further comprising the step of blending a sucrose fatty acid ester.

11. The method according to claim 10, wherein the ratio of sucrose fatty acid ester to 100 parts by mass of sorbitan palmitate is 1 to 300 parts by mass.

12. The method of claim 7 or 8, further comprising a heat sterilization step.

13. A method for producing a dairy beverage according to claim 7 or 8, which is for imparting bacteriostasis against anaerobic heat-resistant spore-forming bacteria to the dairy beverage.

14. An emulsion stabilizer for dairy beverages, containing sorbitan palmitate as an active ingredient, which is used so that the ratio of sorbitan palmitate per part by mass of milk solids in the dairy beverage is 0.0015 parts by mass or more.

15. The emulsion stabilizer for dairy beverages according to claim 14, which is a preparation used to impart bacteriostasis against anaerobic heat-resistant spore-forming bacteria to dairy beverages.

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