Method for producing packaged beverage containing ascorbic acid

Abstract

The present invention addresses the problem of providing a technique for suppressing discoloration over time while maintaining flavor of a beverage in a packaged beverage containing ascorbic acid and having a pH of 5.0-8.0. A heat-sterilized packaged beverage according to the present invention contains 20 ppm or more of ascorbic acid or a salt thereof and 5 ppm or more of caffeine, and is produced by a method including (1) a mixing step for adding a sulfite in an amount that gives a sulfur dioxide (SO2) concentration of 1-30 ppm to a beverage liquid, (2) a pH adjustment step for adjusting the pH of the beverage liquid to 5.0-8.0, and (3) a filling step for filling a container with the beverage liquid.

Description

Method for producing packaged beverage containing ascorbic acid

[0001] The present invention relates to a method for producing a packaged beverage containing ascorbic acid.

[0002] In foods and beverages that are stored for long periods, color change over time can cause significant psychological anxiety to consumers, so preventing the appearance, i.e., discoloration of the food and beverage, is an important issue in preserving and improving the quality of the food and beverage. One cause of discoloration in foods and beverages is the oxidation of food components. Therefore, food additives such as antioxidants are used to prevent oxidation, and ascorbic acid (vitamin C) is often used in packaged beverages due to its excellent antioxidant properties and water solubility.

[0003] However, ascorbic acid is known to brown in aqueous solution due to its own oxidation and decomposition. Furthermore, ascorbic acid is prone to undergo Maillard reactions with amino acids, peptides, proteins, etc., resulting in significant browning due to this Maillard reaction (Non-Patent Document 1). Therefore, methods for inhibiting the browning of ascorbic acid itself have also been proposed. For example, Patent Document 1 describes a method for preventing the browning of ascorbic acid or its derivatives by incorporating a flavonoid glycoside, and Patent Document 2 describes a method for preventing browning by adding sodium sulfite to a beverage containing sugars and ascorbic acids.

[0004] JP-A-4-99771 JP-A-8-256744

[0005] Journal of the Agricultural Chemical Society of Japan, Vol. 50, No. 10, pp. 209-216, 1976

[0006] It is known that the browning of an aqueous solution of ascorbic acid increases at pH 5.0, and the browning becomes more pronounced as the solution becomes more alkaline (Non-Patent Document 1).

[0007] The present invention aims to provide a method for producing a packaged beverage that contains ascorbic acid and has a pH of 5.0 to 8.0, but that is inhibited from discoloring during storage and has a good flavor.

[0008] As a result of extensive research to solve the above problems, the present inventors have found that sulfite is effective in inhibiting browning in an aqueous ascorbic acid solution at a nearly neutral pH range of 5.0 to 8.0. They have also found that caffeine can reduce the off-taste caused by sulfite, which is significantly perceived in the nearly neutral range. This led to the completion of the present invention.

[0009] That is, the present invention relates to the following, but is not limited thereto: [1] A method for producing a heat-sterilized packaged beverage containing 20 ppm or more of ascorbic acid or a salt thereof and 5 ppm or more of caffeine, the method comprising: (1) adding sulfur dioxide (SO ２ (1) a mixing step of adding a sulfite to the beverage liquid in an amount such that the concentration of the sulfite is 1 to 30 ppm; (2) a pH adjusting step of adjusting the pH of the beverage liquid to 5.0 to 8.0; and (3) a filling step of filling the beverage liquid into a container. [2] The method according to [1], wherein the packaged beverage is a beverage containing tea leaf extract. [3] The method according to [1] or [2], wherein the beverage liquid satisfies at least one of the following (a) and (b): (a) carbohydrate content in the beverage: less than 0.5 g / 100 ml; (b) protein content in the beverage: less than 0.5 g / 100 ml. [4] The method according to any one of [1] to [3], wherein the sulfite compound is potassium pyrosulfite. [5] The method according to any one of [1] to [4], wherein the container is a PET container. [6] The method according to any one of [1] to [5], wherein the packaged beverage contains 40 to 1000 ppm of ascorbic acid or a salt thereof.

[0010] According to the present invention, it is possible to provide a packaged beverage that contains ascorbic acid but is inhibited from discoloring due to browning of the ascorbic acid itself, and has a good flavor and is in a substantially neutral pH range.

[0011] FIG. 1 shows photographs of the change in color tone of a green tea beverage over time (Experimental Example 3, top: control beverage, bottom: test beverage).

[0012] The beverage of the present invention is described below. Unless otherwise specified, "ppm" used herein means ppm by weight / volume (w / v). Furthermore, unless otherwise specified, numerical ranges are expressed as including their endpoints.

[0013] Mixing Step In the present invention, a sulfite is added to a liquid beverage containing ascorbic acid or a salt thereof to inhibit discoloration of the beverage caused by browning of ascorbic acid.

[0014] The ascorbic acid or its salt (also simply referred to as "ascorbic acid") used in the present invention is not particularly limited as long as it can be used in beverages.Specific examples include ascorbic acid, sodium ascorbate, potassium ascorbate, calcium ascorbate, etc., with L-ascorbic acid being particularly preferred.When blending ascorbic acid into beverages, ascorbic acid preparations may be added, or ascorbic acid contained in raw materials such as fruit juice may be used.

[0015] In the present invention, ascorbic acid or a salt thereof is added so that the ascorbic acid concentration in the beverage liquid is 20 ppm or more. It is preferably 40 ppm or more, more preferably 60 ppm or more, even more preferably 80 ppm or more, particularly preferably 100 ppm or more, and may be 200 ppm or more. The upper limit of the ascorbic acid concentration is not particularly limited, but from the viewpoint of maintaining a good flavor of the beverage, it is usually 1000 ppm or less, preferably 800 ppm or less, more preferably 600 ppm or less, even more preferably 500 ppm or less, and particularly preferably 400 ppm or less. The ascorbic acid concentration can be measured by a method known to those skilled in the art, such as using HPLC (high performance liquid chromatography), and is calculated as the sum of the contents of ascorbic acid (reduced form) and dehydroascorbic acid (oxidized form).

[0016] In the present invention, browning caused by ascorbic acid in packaged beverages can be suppressed by adding a sulfite to the beverage liquid. The type of sulfite used in the present invention is not limited, and any sulfite that can be used as a food additive in accordance with the laws of each country may be selected. Specific examples include sodium sulfite, sodium hyposulfite, sulfur dioxide, potassium metabisulfite, and sodium metabisulfite, with potassium metabisulfite being particularly preferred in terms of flavor.

[0017] The concentration of sulfite to be added is determined based on the amount of sulfur dioxide (SO ２ The amount of sulfite to be added is calculated so that the concentration of sulfur dioxide produced when sulfite dissociates is 1 to 30 ppm. Here, "as the concentration of sulfur dioxide" means "converted into the concentration of sulfur dioxide produced when sulfite dissociates." For example, the amount of sulfite to be added can be calculated from the following chemical formula: (potassium pyrosulfite)K ２ S ２ O ５ →K ２ O + 2SO ２ (Sodium pyrosulfite) Na ２ S ２ O ５ →Na ２ SO ３ +SO ２ (Sodium sulfite) Na ２ SO ３ +2H+→2Na++H ２ O+SO ２

[0018] The sulfite is preferably added so that the concentration of sulfur dioxide in the beverage is 2 to 25 ppm, and more preferably 3 to 20 ppm or 4 to 20 ppm.

[0019] Sulfites are typically used in foods and beverages with high fat and oil content to prevent deterioration associated with oxidation, primarily occurring in fats and oils, and spoilage (putrefaction) in protein and carbohydrate foods. However, sulfites are not typically added to soft drinks because the flavor (off-flavor) of sulfites themselves impairs the original flavor of the beverage. In particular, the off-flavor of sulfites is more pronounced in beverages that do not contain components that mask the off-flavor derived from sulfites, specifically beverages in the approximately neutral pH range that do not contain lipids or proteins, which can result in an off-flavor of the beverage. The beverage obtained by the present invention has a good flavor with reduced off-flavor derived from sulfites, even in the approximately neutral pH range. Due to the significant effects of the present invention, a beverage in which the beverage liquid satisfies at least one of the following requirements (a) and (b) is an example of a preferred embodiment of the present invention. (a) Carbohydrate content in the beverage: Less than 0.5g / 100ml (b) Protein content in the beverage: Less than 0.5g / 100ml

[0020] In the present invention, the addition of caffeine can reduce the flavor derived from sulfites. In the present invention, caffeine is added so that the caffeine concentration in the beverage is 5 ppm or more. In view of the remarkable effect, the caffeine concentration is preferably 6 ppm or more, more preferably 7 ppm or more, and even more preferably 8 ppm or more. The upper limit of caffeine may be appropriately set in consideration of the flavor of the beverage, but is usually 60 ppm or less, preferably 50 ppm or less, more preferably 40 ppm or less, even more preferably 30 ppm or less, and particularly preferably 25 ppm or less.

[0021] The caffeine used in the present invention may be a monohydrate (C ８ H １０ N ４ O ２ ・H ２ O) or anhydrous (anhydrous caffeine, C ８ H １０ N ４ O ２Caffeine-containing plant extracts can be used either directly or in concentrated or purified form, i.e., caffeine-containing plant extracts obtained by selectively removing components other than caffeine from the caffeine-containing plant extract to increase the caffeine content. Caffeine-containing plant extracts can be produced by extracting coffee beans, cola nuts, tea leaves, cacao, etc. with a solvent such as water or hot water, methanol, ethanol, isopropanol, or ethyl acetate.

[0022] As already mentioned, in the present invention, browning caused by ascorbic acid is inhibited by a sulfite compound, and the effect of the sulfite compound on flavor is reduced by caffeine. In addition, in beverages containing tea leaf extract, caffeine can also prevent discoloration (darkening) caused by catechins contained in the tea leaf extract. In other words, beverages containing tea leaf extract are one of the preferred embodiments of the present invention, since they can further benefit from the effect of the present invention, namely, prevention of discoloration of the liquid color.

[0023] Specifically, beverages containing tea leaf extract are beverages containing an extract from tea leaves of the tea plant (scientific name: Camellia sinensis), including green tea beverages, black tea beverages, and oolong tea beverages. The catechin content in beverages containing tea leaf extract is, for example, 50 to 1500 ppm, preferably 100 to 1400 ppm, more preferably 200 to 1300 ppm, and even more preferably 300 to 1200 ppm. In the present invention, catechins refer collectively to catechin, epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, and epigallocatechin gallate, and the catechin content is defined based on the total amount of the above eight types. The catechin content in a beverage can be measured using high-performance liquid chromatography (HPLC) or the like.

[0024] pH Adjustment Step The present invention targets beverages in the approximately neutral pH range, which are typically susceptible to the browning of ascorbic acid and the unpleasant taste of sulfites. In this specification, the approximately neutral pH range refers to a pH of 5.0 to 8.0. In a preferred embodiment, the beverage of the present invention has a pH of preferably 5.5 to 7.5, more preferably 5.6 to 7.0, and even more preferably 5.7 to 6.8. The production method of the present invention includes a step of adjusting the pH of the beverage liquid to within the above range using a pH adjuster. Examples of pH adjusters that can be used include one or more of sodium bicarbonate (sodium bicarbonate), potassium carbonate, sodium hydroxide, and the like, which are approved as food additives. The amount of pH adjuster added can be determined depending on the type of pH adjuster, so as to achieve the desired pH.

[0025] The pH adjusting step according to the present invention may be carried out separately from the mixing step, or may be carried out simultaneously with the mixing step for preparing the beverage liquid.

[0026] Filling Process The present invention relates to a packaged beverage that can be stored for long periods at room temperature, and is produced by filling a liquid beverage into a container. Here, packaged beverages refer to beverages that are packaged in a container and sealed, including RTD beverages (RTD = Ready To Drink: beverages packaged in PET bottles, cans, bottles, paper bottles, etc., that can be consumed immediately after opening the lid). The containers used for packaged beverages are not particularly limited, and examples include plastic containers such as polyethylene terephthalate (PET), metal cans such as aluminum cans and steel cans, paper containers, and glass bottles. The content volume of the packaged beverage is not particularly limited, but is, for example, 50 mL to 3000 mL, preferably 100 mL to 2000 mL or 200 mL to 1000 mL.

[0027] The present invention includes a filling step of filling a container with a liquid beverage, but heat sterilization is preferably performed for long-term storage at room temperature. Heat sterilization can be performed using conventional techniques, and can be appropriately selected from methods such as filling a container with a liquid beverage and then heat sterilizing (e.g., retort sterilization), or sterilizing the liquid beverage before filling it into a container. For example, when the container is a PET bottle, a paper carton, a bottled beverage, or a pouch beverage, the liquid beverage can be subjected to FP or UHT sterilization, in which the liquid beverage is held at, for example, 90 to 130°C for one to several tens of seconds, and then filled in a predetermined amount. Furthermore, in the case of a can container, the liquid beverage can be filled in a predetermined amount into the can container and then sterilized (e.g., at 85°C for 10 minutes) with the entire container.

[0028] Generally, PET bottles are one of the containers that are susceptible to environmental factors (heat, light, oxygen, etc.) and tend to discolor beverages, but the present invention can effectively prevent discoloration of beverages over time. PET bottle containers are an example of a preferred embodiment of the present invention, as they can greatly benefit from the effects of the present invention.

[0029] From one perspective, the present invention is a method for suppressing discoloration of a beverage caused by ascorbic acid, and from another perspective, the present invention is a method for reducing the effect of sulfites on the flavor of a beverage while suppressing discoloration of a beverage caused by ascorbic acid.

[0030] The present invention will be specifically described in detail below by showing experimental examples, but the present invention is not limited to these examples.

[0031] Experimental Example 1: L-ascorbic acid was used as the ascorbic acid, potassium pyrosulfite as the sulfite, and sodium bicarbonate (sodium bicarbonate) as the pH adjuster. The components shown in the table below were mixed with water to prepare a total volume of 1 L of aqueous solution, and 500 mL of each solution was filled into PET containers (sulfur dioxide concentration of Samples 1-3 and 1-4: approximately 17 ppm). These were stored in an incubator set at 55°C to evaluate the stability of the packaged beverages. Stability was evaluated by visually assessing the degree of coloration before storage (D0), on the 7th day (D7), the 14th day (D14), and the 21st day (D21) of storage.

[0032] As is clear from the results shown in the table below, an aqueous solution of ascorbic acid is prone to coloration at high pH levels, but it was confirmed that sulfite effectively inhibits coloration.

[0033] Experimental Example 2 Using the beverage (D0) of Sample 1-4 from Experimental Example 1 as a control, caffeine was added to the concentrations shown in the table below to produce packaged beverages (heat sterilization conditions: 130°C, 5 minutes). These were stored at 55°C for 14 days, then cooled to 20°C, and a five-person expert panel evaluated their flavor. A caffeinated beverage and a caffeinated beverage were presented in pairs, and each panelist performed a two-point discrimination test to determine which of the presented beverages did not have an unpleasant taste due to sulfites.

[0034] As is clear from the results in the table below, in beverages with a pH of 6.5, the flavor derived from sulfites is perceived as an off-taste, but it has been found that the off-taste can be reduced by adding caffeine.

[0035] Experimental Example 3 A green tea beverage was prepared using a caffeine-containing green tea extract to confirm the effects of the present invention.

[0036] First, 20 g of green tea leaves (low-grade sencha) were extracted with 1000 mL of hot water (70-80°C) for 5 minutes, and the tea leaves were separated. The extract was then passed through a 200-mesh sieve to remove solids such as ground tissue and tea particles. Water was then added to the resulting liquid to give a concentration of 47.5 mg / 100 mL to prepare a green tea extract. The caffeine content of the green tea extract was 12 ppm, and the catechin content was 420 ppm.

[0037] Next, this green tea extract was mixed with 250 ppm of L-ascorbic acid and 150 ppm of potassium pyrosulfite, and the pH was adjusted to 6.4 using 290 ppm of sodium bicarbonate. This beverage was then heat sterilized at 125°C for 7 minutes, and 500 mL of each was filled into PET containers to produce a packaged beverage (test beverage, Sample 3-2, sulfur dioxide concentration: approximately 14 ppm). A control beverage (control beverage, Sample 3-1) was prepared in the same manner, except that the ascorbic acid concentration was 320 ppm and potassium pyrosulfite was not added. The carbohydrate and protein contents of both the test and control beverages were less than 0.5 g / 100 ml.

[0038] These were stored in an incubator set at 55° C. and stability was evaluated. Stability was evaluated by visually observing the liquid color (degree of browning) of the beverage before storage (D0), on day 7 (D7), day 14 (D14), day 21 (D21), and day 25 (D25) of storage.

[0039] The evaluation results are summarized in the table below. As is clear from the photograph of the appearance of the green tea beverage (Figure 1), the beverage (Sample 3-2) produced by adding sulfite (potassium pyrosulfite) effectively suppressed not only the browning caused by ascorbic acid but also the darkening of catechins, maintaining a vivid green color.

Claims

1. A method for producing a heat-sterilized packaged beverage containing 20 ppm or more of ascorbic acid or its salt and 5 ppm or more of caffeine, comprising: ２ a pH adjusting step of adjusting the pH of the beverage liquid to 5.0 to 8.0; and a filling step of filling the beverage liquid into a container.

2. The method according to claim 1, wherein the packaged beverage is a beverage containing tea leaf extract.

3. The method according to claim 1, wherein the beverage satisfies at least one of the following (a) and (b): (a) carbohydrate content in the beverage: less than 0.5 g / 100 ml; and (b) protein content in the beverage: less than 0.5 g / 100 ml.

4. The method of claim 1, wherein the sulfite compound is potassium pyrosulfite.

5. The method of claim 1, wherein the container is a PET container.

6. The method according to claim 1, wherein the packaged beverage contains 40 to 1000 ppm of ascorbic acid or a salt thereof.

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