Bottled black tea beverage with suppressed heating-induced off-flavor, and method for producing the same

Abstract

The present invention addresses the problem of providing: a bottled black tea beverage in which heating-induced off-flavor is suppressed but flavor of the black tea beverage is preserved; and a method for producing the same.　The problem addressed by the present invention can be solved by a bottled black tea beverage in which tannin content is 15 mg / 100 mL or more, wherein the beverage is prepared such that (i) the indole content is 30-2,000 ppb and / or (ii) the nerolidol content is 10-5,000 ppb.

Description

Container-packed black tea beverage with suppressed heat deterioration odor, and method for producing the same

[0001] The present invention relates to a container-packed black tea beverage with suppressed heat deterioration odor while maintaining the flavor of the black tea beverage, and a method for producing the same, etc.

[0002] Tea beverages have been a representative beverage that has been loved as a preferred beverage and a health beverage since ancient times, due to their unique aroma and refreshing flavor produced by bitterness and astringency. There are tea beverages prepared from various teas such as green tea, semi-fermented tea (oolong tea), fermented tea (black tea), etc. In recent years, they are distributed as container-packed beverages such as canned, PET bottle-packed, or paper pack. Black tea beverages are one of the beverages particularly favored among tea beverages in terms of preference or health consciousness, due to the unique aroma of black tea and the taste with bitterness and astringency. Black tea beverages prepared with various flavor variations are provided as container-packed black tea beverages filled in cans, PET bottles, etc.

[0003] For container-packed tea beverages, heat deterioration odor is an issue. For example, in Patent Document 1, a method for alleviating heat deterioration odor is described in a tea beverage containing amino acids at a high concentration, by setting caffeine to 150 ppm or more and furaneol to 50 ppb or more.

[0004] Japanese Patent Application Laid-Open No. 2011-97905

[0005] An object of the present invention is to provide a container-packed black tea beverage with suppressed heat deterioration odor while maintaining the flavor of the black tea beverage, and a method for producing the same, etc.

[0006] In order to solve the above problems, the present inventors earnestly studied various methods. As a result, in a container-packed black tea beverage having a tannin content concentration of 15 mg / 100 mL or more, by preparing the container-packed black tea beverage such that (i) the indole content concentration is 30 to 2000 ppb and / or (ii) the nerolidol content concentration is 10 to 5000 ppb, it was found that the heat deterioration odor can be suppressed while maintaining the flavor of the black tea beverage, and thus the present invention was completed.

[0007] In other words, the present invention provides the following inventions, etc. [1] A packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, wherein at least one of the following conditions (i) and (ii) is met: (i) the indole content is 30 to 2000 ppb; (ii) the nerolidol content is 10 to 5000 ppb; [2] The packaged black tea beverage according to [1] above, wherein both of the following conditions (i) and (ii) are met: (i) the indole content is 30 to 2000 ppb; (ii) the nerolidol content is 10 to 5000 ppb; [3] A method for producing a packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, comprising preparing the packaged black tea beverage such that it meets at least one of the following conditions (i) and (ii): (i) the indole content is 30 to 2000 ppb (ii) The manufacturing method wherein the nerolidol content is 10 to 5000 ppb; (4) A method for suppressing heating-induced off-odor in a packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, while maintaining the flavor of the black tea beverage, comprising preparing the packaged black tea beverage such that it satisfies at least one of the following conditions (i) and (ii): (i) the indole content is 30 to 2000 ppb; (ii) the nerolidol content is 10 to 5000 ppb;

[0008] According to the present invention, it is possible to provide a packaged black tea beverage in which the flavor and aroma of the black tea beverage are maintained while the odor of heat degradation is suppressed, as well as a method for producing the same.

[0009] The present invention relates to: [1] A packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, satisfying at least one of the following conditions (i) and (ii): (i) having an indole content of 30 to 2000 ppb; (ii) having a nerolidol content of 10 to 5000 ppb (hereinafter also referred to as "the beverage of the present invention"); [2] A method for producing a packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, comprising preparing the packaged black tea beverage so that it satisfies at least one of the following conditions (i) and (ii): (i) having an indole content of 30 to 2000 ppb; (ii) having a nerolidol content of 10 to 5000 ppb (hereinafter also referred to as "the method for producing the present invention"); [3] A method for suppressing off-flavors due to heat degradation in a packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, while maintaining the flavor of the black tea beverage, comprising preparing the packaged black tea beverage so that it satisfies at least one of the following conditions (i) and (ii): (i) the indole content is 30 to 2000 ppb; (ii) the nerolidol content is 10 to 5000 ppb; the above method (hereinafter also referred to as "the suppression method of the present invention"); and other embodiments. In this specification, "ppb (parts per billion)" represents the mass per unit volume and is synonymous with "μg / L".

[0010] (Packaged Black Tea Beverage) The beverage of the present invention is a packaged black tea beverage. The "black tea beverage" in the present invention is not particularly limited as long as it is a beverage containing black tea extract, but black tea beverages are preferred.

[0011] Tea beverages contain tea extracts. In this invention, "tea extract" refers to an extract obtained by subjecting tea leaves to an extraction process. The tea extract may be a liquid or a solid such as a powder. Examples of tea extracts used in this invention include the extract from tea leaves (tea leaf extract) itself, processed products thereof (e.g., concentrated liquid extract, powder extract), or diluted solutions thereof. There are no particular limitations, and any tea extract raw material conventionally used in the manufacture of tea beverages can be appropriately selected. In this invention, the extraction process refers to a process in which tea components are eluted into an extraction solvent.

[0012] The tea leaves that can be used as raw materials for black tea extract are not particularly limited, and examples include tea leaves obtained from the Chinese variety (var. sinensis), the Assam variety (var. assamica), or hybrids thereof, which have been processed through a fermentation process. The tea season, shape of the tea leaves, origin, variety, grade, and fermentation conditions are also not particularly limited and can be set appropriately by those skilled in the art. Furthermore, the conditions for extracting the tea leaves, such as the amount of tea leaves, the amount of solvent, the extraction temperature, and the extraction time, are not particularly limited and can be the same as those normally used for extracting black tea leaves.

[0013] (Tannins) The tannin content in the beverage of the present invention is not particularly limited as long as it is 15 mg / 100 mL or more, but for example, 20 mg / 100 mL or more and 25 mg / 100 mL or more are given. From the viewpoint of more frequently experiencing the problem of heat-induced deterioration odor and more enjoying the effects of the present invention, 30 mg / 100 mL or more, 35 mg / 100 mL or more, 40 mg / 100 mL or more and 45 mg / 100 mL or more are given. The upper limit of the tannin content in the beverage of the present invention is not particularly limited, but for example, 100 mg / 100 mL or less, 90 mg / 100 mL or less, 80 mg / 100 mL or less, 70 mg / 100 mL or less and 60 mg / 100 mL or less are given. These lower and upper limits can be arbitrarily combined, for example, 15 to 100 mg / 100 mL, 30 to 90 mg / 100 mL and 35 to 80 mg / 100 mL are given.

[0014] In the present invention, the tannin concentration in the beverage can be adjusted, for example, by adjusting the amount of tea leaves used when preparing the tea extract, or by adjusting the amount of processed tea extract used.

[0015] The tannin concentration in the beverage of the present invention can be measured using the ferric tartrate spectrophotometric method (preferably the official method described in "Commentary on the Fifth Revised Japanese Standard Food Composition Analysis Manual" edited by the Japan Food Research Laboratories (Chuo Hoki, July 2001, p. 252)). In this measurement method, the purple component produced by reacting polyphenols in the liquid with ferric tartrate reagent is measured for absorption (540 nm), and the tannin can be quantified using a calibration curve prepared with ethyl gallate as the standard substance. The amount of tannin can be obtained by multiplying the quantitative value obtained in this way by 1.5.

[0016] (i: Indole) The indole content in the beverage of the present invention is not particularly limited as long as it is between 30 and 2000 ppb. The lower limit is not particularly limited as long as it is 30 ppb or more, for example, 40 ppb or more, 50 ppb or more, 60 ppb or more, 70 ppb or more, 80 ppb or more, and 90 ppb or more. From the viewpoint of suppressing heating-induced odors to a greater extent, 100 ppb or more, 200 ppb or more, 300 ppb or more, 400 ppb or more, 500 ppb or more, 600 ppb or more, 700 ppb or more, 800 ppb or more, and 900 ppb or more are preferred, and 1000 ppb or more, 1100 ppb or more, 1200 ppb or more, 1300 ppb or more, 1400 ppb or more, and 1500 ppb or more are more preferred. Furthermore, the upper limit is not particularly limited as long as it is 2000 ppb or less, and examples include 1800 ppb or less, 1600 ppb or less, 1400 ppb or less, 1200 ppb or less, and 1000 ppb or less. These upper and lower limits can be combined arbitrarily, and examples include 100 to 2000 ppb, 500 to 1800 ppb, and 1000 to 1600 ppb. In addition, the ratio of indole content (ppb) to tannin content (mg / 100 mL) in the beverage of the present invention is not particularly limited, but examples of lower limits include 0.33 or more, preferably 0.5 or more, 1 or more, 1.7 or more, and 17 or more, and examples of upper limits include 133 or less, preferably 67 or less, 22 or less, and 17 or less. These upper and lower limits can be combined in any way, for example, 0.33 to 133, 0.5 to 67, and 1 to 22.

[0017] The indole concentration in the beverage of the present invention can be adjusted, for example, by adding indole or an indole-containing composition. The indole or indole-containing composition is not particularly limited, and commercially available products can be used, for example.

[0018] The indole concentration in beverages can be measured by known methods, such as those using gas chromatography or high-performance liquid chromatography.

[0019] (ii: Nerolidol) The concentration of nerolidol in the beverage of the present invention is not particularly limited as long as it is between 10 and 5000 ppb. The lower limit is not particularly limited as long as it is 10 ppb or more, for example, 20 ppb or more, 30 ppb or more, 40 ppb or more, 50 ppb or more, 60 ppb or more, 70 ppb or more, 80 ppb or more, and 90 ppb or more. From the viewpoint of suppressing heating-induced odors to a greater extent, 100 ppb or more, 200 ppb or more, 300 ppb or more, 400 ppb or more, 500 ppb or more, 600 ppb or more, 700 ppb or more, 800 ppb or more, and 900 ppb or more are preferred, and 1000 ppb or more, 2000 ppb or more, and 3000 ppb or more are more preferred. Furthermore, the upper limit is not particularly limited as long as it is 5000 ppb or less, and examples include 4500 ppb or less, 4000 ppb or less, 3500 ppb or less, 3000 ppb or less, and 2000 ppb or less. These upper and lower limits can be combined arbitrarily, and examples include 100 to 5000 ppb, 500 to 4500 ppb, and 1000 to 4000 ppb. Furthermore, the ratio of the nerolidol content (ppb) to the tannin content (mg / 100 mL) in the beverage of the present invention is not particularly limited, but examples of lower limits include 0.11 or more, preferably 0.33 or more, 0.67 or more, 1 or more, 1.7 or more, and 17 or more, and examples of upper limits include 333 or less, preferably 167 or less, 83 or less, and 67 or less. These upper and lower limits can be combined in any way, for example, 0.11 to 333, 0.33 to 167, and 0.67 to 83.

[0020] The concentration of nerolidol in the beverage of the present invention can be adjusted, for example, by adding nerolidol or a nerolidol-containing composition. The nerolidol or nerolidol-containing composition is not particularly limited, and commercially available products can be used, for example.

[0021] The concentration of nerolidol in beverages can be measured by known methods, such as gas chromatography or high-performance liquid chromatography.

[0022] (Combination of i and ii) The beverage of the present invention only needs to satisfy at least one of the following conditions: (i) the indole content is 30 to 2000 ppb, and (ii) the nerolidol content is 10 to 5000 ppb. However, satisfying both of the above conditions (i) and (ii) is more preferable from the viewpoint of obtaining more of the effects of the present invention. When the beverage of the present invention satisfies both conditions (i) and (ii) above, the ratio of the nerolidol content (ppb) to the indole content (ppb) is not particularly limited, but the lower limit can be, for example, 0.02 or more, 0.05 or more, 0.1 or more, 0.33 or more, 0.5 or more, 1 or more, 5 or more, 10 or more, 30 or more, 50 or more, 70 or more, 90 or more, or 100 or more, and the upper limit can be, for example, 167 or less, 150 or less, 130 or less, 100 or less, 80 or less, 60 or less, 40 or less, 20 or less, 15 or less, 8 or less, 5 or less, or 1 or less. These upper and lower limits can be arbitrarily combined, for example, 0.02 to 167, 0.5 to 100, or 1 to 40.

[0023] (Optional Components) The beverage of the present invention may or may not contain one or more selected from the group consisting of, for example, acidulants, colorants, sweeteners, antioxidants (such as L-ascorbic acid), preservatives, thickeners and stabilizers, emulsifiers, vegetable oils and fats, milk components, and pH adjusters (such as baking soda). As one form of the beverage of the present invention, from the viewpoint of obtaining more of the effects of the present invention, a beverage containing one or more selected from the group consisting of L-ascorbic acid and its salts (for example, alkali metal salts such as sodium salt and potassium salt, and alkaline earth metal salts such as magnesium salt and calcium salt) is preferred. When the beverage of the present invention contains one or more selected from the group consisting of L-ascorbic acid and its salts, there are no particular restrictions on the concentration thereof, but the total concentration of L-ascorbic acid and its salts (concentration converted to L-ascorbic acid in the case of salts) is, for example, 0.02 to 0.3% by mass, preferably 0.04 to 0.1% by mass.

[0024] Examples of the "sweeteners" mentioned above include monosaccharides such as fructose, glucose, tagatose, and arabinose; disaccharides such as lactose, trehalose, maltose, and sucrose; oligosaccharides such as maltooligosaccharides and galactooligosaccharides; amorphous sugars such as corn syrup and isomerized liquid sugar (e.g., fructose-glucose liquid sugar); sugar alcohols such as maltitol, lactitol, sorbitol, mannitol, xylitol, and erythritol; and high-intensity sweeteners such as sucralose, stevia, licorice extract, thaumatin, glycyrrhizin, saccharin, aspartame, and acesulfame K. From the viewpoint of natural sweetness, sugars (crystalline and amorphous sugars) are preferred, and from the viewpoint of low calorie content, sugar alcohols and high-intensity sweeteners are preferred. When using sweeteners, there are no particular limitations on the concentration of sweeteners in the beverage of the present invention.

[0025] (Container) The beverage of the present invention is a beverage in a container. Examples of such containers include resin bottle containers such as PET (polyethylene terephthalate) bottles, polypropylene bottles, and polyvinyl chloride bottles; glass bottles; cans; paper containers; and containers other than glass bottles (resin bottles, cans, and paper containers) are preferred, resin bottles are more preferred, and PET bottles are even more preferred.

[0026] (pH) The pH of the tea beverage in the packaged tea beverage in this case is not particularly limited, and examples include 3.0 to 7.0, 3.5 to 7.0, 4.0 to 7.0, 4.0 to 6.5, 4.5 to 6.5, and 5.0 to 6.5.

[0027] (Heat Sterilization Treatment) The beverage of the present invention is heat sterilized. The heat sterilization method and conditions can be those of ordinary beverages used for bottled beverages, etc. For example, in cases where heat sterilization can be performed after filling, such as in metal cans, sterilization can be performed under the sterilization conditions specified in the Food Sanitation Act. Furthermore, in cases where retort sterilization is not possible, such as in PET bottles and paper containers, a method can be adopted in which the beverage is sterilized in advance under sterilization conditions equivalent to those described above, for example, by high-temperature short-time sterilization (UHT sterilization) using a plate-type heat exchanger, etc., before filling, then cooled to a certain temperature, and then filled into the sterilized container.

[0028] (Manufacturing Method of the Present Invention) The manufacturing method of the present invention is not particularly limited as long as it is a method for producing a packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, and includes preparing the packaged black tea beverage so that it satisfies at least one of the following conditions (i) and (ii) (preferably both conditions (i) and (ii)): (i) the indole content is 30 to 2000 ppb; (ii) the nerolidol content is 10 to 5000 ppb;

[0029] The present invention relates to a method for producing a packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, and can be produced by a general method for producing packaged black tea beverages, except that the packaged black tea beverage is prepared to satisfy at least one of the above conditions (i) and (ii) (preferably both conditions (i) and (ii)). A general method for producing packaged black tea beverages is well known, and for example, a black tea extract can be prepared, and the black tea beverage can be produced through a blending step, a filling step, and a heat sterilization step. In the production of the beverage of the present invention, the above-mentioned optional components may be included, and the timing of the addition of these optional components is not particularly limited.

[0030] A method for preparing a packaged black tea beverage such that it satisfies at least one of the above conditions (i) and (ii) (preferably both conditions (i) and (ii)) is to include indole and / or nerolidol, or a composition containing them, in the beverage of the present invention in any of the manufacturing steps of the packaged black tea beverage such that the content concentration of one or two selected from indole and nerolidol satisfies at least one of the above conditions (i) and (ii) (preferably both conditions (i) and (ii)). For example, this method involves including indole and / or nerolidol, or a composition containing them, in a black tea extract.

[0031] In the manufacturing method of the present invention, there are no particular restrictions on the order in which the raw materials are added, as long as the beverage of the present invention can be produced. After preparing a liquid in which the raw materials are mixed, the liquid can be filled into a container and sealed to obtain the beverage of the present invention.

[0032] (Suppression Method of the Present Invention) The suppression method of the present invention is a method for suppressing off-flavors from heat deterioration in a packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, while maintaining the flavor of the black tea beverage, and is not particularly limited as long as it includes preparing the packaged black tea beverage so that it satisfies at least one of the following conditions (i) and (ii) (preferably both conditions (i) and (ii)): (i) the indole content is 30 to 2000 ppb; (ii) the nerolidol content is 10 to 5000 ppb;

[0033] A method for preparing a packaged tea beverage such that it satisfies at least one of the above conditions (i) and (ii) (preferably both conditions (i) and (ii)) can be the same as the method described above (Manufacturing Method of the Invention).

[0034] (Packaged black tea beverage with suppressed heat-induced odor) The packaged black tea beverage of the present invention is a packaged black tea beverage in which heat-induced odor is suppressed. "Heat-induced odor" refers to the odor of deterioration that occurs when packaged black tea beverages are heat-sterilized, and specifically includes a medicinal smell like herbal medicine, a musty smell, a potato smell, and a rubbery smell.

[0035] In this specification, a packaged black tea beverage with "suppressed heat-induced odor" refers to a beverage in which heat-induced odor is suppressed compared to a packaged black tea beverage (hereinafter also referred to as "control beverage") in which the indole content is less than 30 ppb (preferably 20 ppb or less, more preferably 10 ppb or less, and even more preferably 5 ppb or less) and the nerolidol content is less than 10 ppb (preferably 7 ppb or less, more preferably 4 ppb or less, and even more preferably 2 ppb or less). Whether or not a black tea beverage has suppressed heat-induced odor can be determined by using the average of evaluations from multiple panelists, for example, based on the heat-induced odor of the control beverage.

[0036] (Packaged Black Tea Beverage with Maintained Flavor) The beverage of the present invention is preferably a packaged black tea beverage in which the flavor of the black tea beverage is maintained. In this specification, "flavor of the black tea beverage" refers to a flavor characteristic of black tea, and a packaged black tea beverage in which the "flavor of the black tea beverage is maintained" refers to a packaged black tea beverage in which off-flavors and off-odors other than heat-induced deterioration odors are within an acceptable range for a black tea beverage. Whether or not the "flavor of the black tea beverage" is maintained in a given black tea beverage can be easily and clearly determined by a panel. Packaged black tea beverages in which the "flavor of the black tea beverage" is not maintained include packaged black tea beverages in which off-flavors derived from any of the ingredients are so excessive that they disrupt the harmony of the flavor as a black tea beverage, and more specifically, packaged black tea beverages with an indole content of more than 3000 ppb or packaged black tea beverages with a nerolidol content of more than 10000 ppb.

[0037] The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples.

[0038] Test 1. [Effect of tannin concentration on heat-induced off-odor in black tea beverages] The following test was conducted to investigate how the tannin concentration in black tea beverages affects the heat-induced off-odor.

[0039] (1. Preparation of Sample Black Tea Beverages) Black tea leaves were steeped in 90°C water for 7 minutes, and solid-liquid separation was performed to prepare a black tea extract. The tannin content of this black tea extract was measured using the official method (ferrous tartrate absorbance method) described in "Commentary on the Fifth Revised Japanese Standard Food Composition Analysis Manual" edited by the Japan Food Research Laboratories (Chuo Hoki, July 2001, p. 252). L-ascorbic acid (final concentration 0.04% by mass) was added to each black tea extract, which was adjusted so that the tannin content (final concentration) was as shown in Table 2, and sodium bicarbonate was added to adjust the pH to approximately 6.0. These black tea extracts were filled into cans and subjected to retort sterilization (heat and pressure sterilization) under conditions equivalent to 121°C for 5 minutes to prepare the sample beverages for Test Examples 1 to 5. The pH of each sample beverage after heat sterilization was measured using a pH meter and was approximately 5.7 in all cases.

[0040] (2. Sensory Evaluation Test) Five trained professional panelists conducted a sensory evaluation test on the heat-degraded odor of each sample black tea beverage. Specifically, the heat-degraded odor of the sterilized product of each test example was evaluated in comparison to the heat-degraded odor of the unsterilized product of that test example (i.e., a medicinal odor like herbal medicine, a musty odor, a potato odor, a rubbery odor). The heat-degraded odor was evaluated on a 41-point scale from 1.0 to 5.0 in 0.1-point increments, based on the [Evaluation Criteria] in Table 1 below. The average of the evaluation scores of the five professional panelists, rounded to two decimal places, was adopted as the sensory evaluation test result for that sample black tea beverage. As a standard for evaluation, the degree of heat-degraded odor of the sterilized product of Test Example 1 compared to the unsterilized product of Test Example 1 was set at 1.0 points, and the degree of heat-degraded odor of the sterilized product of Test Example 5 compared to the unsterilized product of Test Example 5 was set at 5.0 points. Furthermore, the difference of 0.1 points between 1.0 and 5.0 points was considered to be of similar magnitude. Incidentally, the standard deviation of the evaluation score for heat-induced odor degradation was 0.5 or less for all sample black tea beverages in Test Examples 1 to 5.

[0041]

[0042] For the sample black tea beverages of Test Examples 1 to 5, the results of the sensory evaluation test are shown in Table 2.

[0043]

[0044] From the results in Table 2, it was shown that when the tannin content concentration of the black tea beverage was 15 mg / 100 mL or more, the evaluation of the heating deterioration odor was 2.0 points or more, indicating that the problem of heating deterioration odor occurred. Also, it was shown that as the tannin content concentration increased, the problem of heating deterioration odor became larger.

[0045] Test 2. [Effect of indole on the heating deterioration odor of black tea beverages] The effect of indole on the heating deterioration odor of black tea beverages was investigated by the following experiment.

[0046] (1. Preparation of sample black tea beverages) Black tea leaves were put into hot water at 90°C and extracted for 7 minutes, followed by solid-liquid separation to prepare a black tea extract. The tannin content concentration of this black tea extract was measured by the official method (tartaric acid iron absorbance method) described in "Explanation of the Fifth Revised Japanese Food Standard Composition Analysis Manual" (edited by the Japan Food Analysis Center, Chuouhouki, July 2001, p. 252). Indole was added to each black tea extract adjusted so that the tannin content concentration (final concentration) was the concentration shown in Table 4, L-ascorbic acid (final concentration 0.04% by mass) was added, and sodium hydrogen carbonate was added so that the pH was about 6.0. Each of these black tea extracts was filled into a can container and subjected to retort sterilization (heating and pressurization sterilization) under conditions equivalent to 121°C for 5 minutes to prepare each sample beverage of Test Examples 6 to 11. Also, as a control beverage, a sample beverage of Test Example 4 without added indole was prepared. When the pH of each sample beverage after heat sterilization was measured using a pH meter, it was about 5.7 for all of them.

[0047] (2. Sensory evaluation test) For the heating deterioration odor of each sample black tea beverage, a sensory evaluation test was conducted in the same manner as the method described in Test 1.

[0048] Furthermore, sensory evaluation tests were conducted on the "flavor disharmony" of each sample black tea beverage. Specifically, "flavor disharmony" was evaluated for off-flavors and off-odors other than those caused by heat degradation. Flavor disharmony was evaluated on a 31-point scale from 1.0 to 4.0 in 0.1-point increments, based on the [Evaluation Criteria] in Table 3 below. The average of the evaluation scores from five expert panelists, rounded to two decimal places, was adopted as the sensory evaluation result for each sample black tea beverage. As a standard for evaluation, the degree of flavor disharmony in Test Example 4 was set at 1.0 points, and the degree of flavor disharmony in Test Example 11 was set at 4.0 points. The difference in degree between 0.1 points from 1.0 to 4.0 points was considered to be of a similar magnitude. Incidentally, the standard deviation of the evaluation scores for flavor disharmony was 0.5 or less for all sample black tea beverages from Test Examples 6 to 11.

[0049]

[0050] Table 4 shows the results of the sensory evaluation tests for the sample black tea beverages in Test Examples 6-11 and 4.

[0051]

[0052] The results in Table 4 show that when the indole content of a black tea beverage is 30 ppb or higher, the evaluation score for the degree of heat-induced off-flavor is 4.0 or lower, indicating that heat-induced off-flavor is suppressed. Furthermore, it was shown that the more the indole content increases, the greater the suppression of heat-induced off-flavor. On the other hand, when the indole content is 3000 ppb, although the heat-induced off-flavor is significantly suppressed, the indole flavor becomes too strong, resulting in a strong degree of flavor disharmony, making it undesirable as a black tea beverage.

[0053] Experiment 3. [Effect of nerolidol on the heat-induced off-odor of black tea beverages] The effect of nerolidol on the heat-induced off-odor of black tea beverages was investigated through the following experiment.

[0054] (1. Preparation of Sample Black Tea Beverages) Black tea leaves were steeped in 90°C water for 7 minutes, and solid-liquid separation was performed to prepare a black tea extract. The tannin content of this black tea extract was measured using the official method (ferrous tartrate absorbance method) described in "Commentary on the Fifth Revised Japanese Standard Food Composition Analysis Manual" edited by the Japan Food Research Laboratories (Chuo Hoki, July 2001, p. 252). Nerolidol was added to each black tea extract, which was adjusted so that the tannin content (final concentration) was as shown in Table 5, to the concentration shown in Table 5, L-ascorbic acid (final concentration 0.04 mass%) was added, and sodium bicarbonate was added to bring the pH to approximately 6.0. These black tea extracts were filled into cans and subjected to retort sterilization (heat and pressure sterilization) under conditions equivalent to 121°C for 5 minutes to prepare the sample beverages for Test Examples 12 to 17. In addition, a sample beverage of Test Example 4, in which nerolidol was not added, was prepared as a control beverage. Furthermore, when the pH of each sample beverage after heat sterilization was measured using a pH meter, it was found to be approximately 5.7 in all cases.

[0055] (2. Sensory Evaluation Test) For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 1 to assess the odor of heat degradation. For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 2 to assess the flavor disharmony.

[0056] Table 5 shows the results of the sensory evaluation tests for the sample black tea beverages in Test Examples 12-17 and 4.

[0057]

[0058] The results in Table 5 show that when the nerolidol content of a black tea beverage is 10 ppb or higher, the evaluation score for the degree of heat-induced off-flavor is 4.0 or lower, indicating that heat-induced off-flavor is suppressed. Furthermore, it was shown that the suppression of heat-induced off-flavor increases with higher nerolidol content. On the other hand, when the nerolidol content is 10,000 ppb, although the heat-induced off-flavor is significantly suppressed, the nerolidol flavor becomes too strong, resulting in a strong degree of flavor disharmony, making it undesirable as a black tea beverage.

[0059] Experiment 4. [Effects of combined use of indole and nerolidol on the heat-induced odor of black tea beverages 1] The effect of combined use of indole and nerolidol on the heat-induced odor of black tea beverages was investigated by the following experiment.

[0060] (1. Preparation of Sample Black Tea Beverages) Black tea leaves were steeped in 90°C water for 7 minutes, and solid-liquid separation was performed to prepare a black tea extract. The tannin content of this black tea extract was measured using the official method (ferrous tartrate absorbance method) described in "Commentary on the Fifth Revised Japanese Standard Food Composition Analysis Manual" edited by the Japan Food Research Laboratories (Chuo Hoki, July 2001, p. 252). Indole and nerolidol were added to each black tea extract adjusted to the tannin content (final concentration) shown in Table 6, L-ascorbic acid (final concentration 0.04% by mass) was added, and sodium bicarbonate was added to bring the pH to approximately 6.0. These black tea extracts were filled into cans and subjected to retort sterilization (heat and pressure sterilization) under conditions equivalent to 121°C for 5 minutes to prepare the sample beverages for Test Examples 18 to 21. In addition, a sample beverage of Test Example 4 was prepared as a control beverage, without the addition of either indole or nerolidol. The pH of each sample beverage after heat sterilization was measured using a pH meter, and all were approximately 5.7.

[0061] (2. Sensory Evaluation Test) For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 1 to assess the odor of heat degradation. For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 2 to assess the flavor disharmony.

[0062] Table 6 shows the results of the sensory evaluation tests for the sample black tea beverages in Test Examples 18-21 and 4.

[0063]

[0064] The results in Table 6 show that the combined use of indole and nerolidol more effectively suppresses heat-induced odors. More specifically, in Test Examples 18 and 20, where 30 ppb of indole and nerolidol were used in combination, heat-induced odors were more effectively suppressed compared to Test Example 7 (Table 4), where indole was 30 ppb. Furthermore, in Test Example 21, where 2000 ppb of indole and nerolidol were used in combination, heat-induced odors were more effectively suppressed compared to Test Example 10 (Table 4), where indole was 2000 ppb.

[0065] Experiment 5. [Effects of combined use of indole and nerolidol on the heat-induced odor degradation of black tea beverages 2] The following experiment investigated whether indole and nerolidol have an effect of suppressing heat-induced odor degradation, even when sucrose is used.

[0066] (1. Preparation of Sample Black Tea Beverages) Black tea leaves were steeped in 90°C water for 7 minutes, and solid-liquid separation was performed to prepare a black tea extract. The tannin content of this black tea extract was measured using the official method (ferrous tartrate absorbance method) described in "Commentary on the Fifth Revised Japanese Standard Food Composition Analysis Manual" edited by the Japan Food Research Laboratories (Chuo Hoki, July 2001, p. 252). Indole, nerolidol, sucrose, and L-ascorbic acid (final concentration 0.04% by mass) were added to each black tea extract adjusted to the tannin content (final concentration) shown in Table 7, and sodium bicarbonate was added to achieve the concentrations shown in Table 7, and sodium bicarbonate was added to adjust the pH to approximately 6.0. These black tea extracts were filled into cans and subjected to retort sterilization (heat and pressure sterilization) under conditions equivalent to 121°C for 5 minutes to prepare the sample beverage for Test Example 23. In addition, a sample beverage of Test Example 22 was prepared as a control beverage, without the addition of either indole or nerolidol. The pH of each sample beverage after heat sterilization was measured using a pH meter and was found to be approximately 5.6 in all cases.

[0067] (2. Sensory Evaluation Test) For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 1 to assess the odor of heat degradation. For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 2 to assess the flavor disharmony.

[0068] Table 7 shows the results of the sensory evaluation tests for the sample black tea beverages in Test Examples 22 and 23.

[0069]

[0070] The results in Table 7 show that even when sucrose is used, indole and nerolidol have the effect of suppressing the odor caused by heating.

[0071] Experiment 6. [Effects of combined use of indole and nerolidol on the heat-induced odor degradation of black tea beverages 3] The following experiment investigated whether indole and nerolidol have an effect of suppressing heat-induced odor degradation even in black tea beverages with an acidic pH and containing sucrose.

[0072] (1. Preparation of Sample Black Tea Beverages) Black tea leaves were steeped in 90°C water for 7 minutes, and solid-liquid separation was performed to prepare a black tea extract. The tannin content of this black tea extract was measured using the official method (ferrous tartrate absorbance method) described in "Commentary on the Fifth Revised Japanese Standard Food Composition Analysis Manual" edited by the Japan Food Research Laboratories (Chuo Hoki, July 2001, p. 252). Indole, nerolidol, sucrose, acidulants (citric acid and trisodium citrate), and L-ascorbic acid (final concentration 0.04% by mass) were added to each black tea extract adjusted to the tannin content (final concentration) shown in Table 8, and sodium bicarbonate was added to achieve the concentrations shown in Table 8, and sodium bicarbonate was added to adjust the pH to approximately 4.0. Each of these black tea extracts was filled into canned containers and retort sterilized (heat-pressure sterilization) under conditions equivalent to 124°C for 30 seconds to prepare the sample beverage for Test Example 25. In addition, a sample beverage of Test Example 24 was prepared as a control beverage, without the addition of either indole or nerolidol. The pH of each sample beverage after heat sterilization was measured using a pH meter, and all were approximately 4.0.

[0073] (2. Sensory Evaluation Test) For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 1 to assess the odor of heat degradation. For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 2 to assess the flavor disharmony.

[0074] Table 8 shows the results of the sensory evaluation tests for the sample black tea beverages in Test Examples 24 and 25.

[0075]

[0076] The results in Table 8 show that even in tea beverages with an acidic pH and containing sucrose, indole and nerolidol have the effect of suppressing the odor caused by heat degradation.

[0077] Experiment 7. [Effects of combined use of indole and nerolidol on the heat-induced odor degradation of black tea beverages 4] The following experiment investigated whether indole and nerolidol have an effect on suppressing heat-induced odor degradation, even in black tea beverages that are acidic in pH and contain sucrose and fruit juice.

[0078] (1. Preparation of Sample Black Tea Beverages) Black tea leaves were steeped in 90°C water for 7 minutes, and solid-liquid separation was performed to prepare a black tea extract. The tannin content of this black tea extract was measured using the official method (ferrous tartrate absorbance method) described in "Commentary on the Fifth Revised Japanese Standard Food Composition Analysis Manual" edited by the Japan Food Research Laboratories (Chuo Hoki, July 2001, p. 252). Indole, nerolidol, sucrose, acidulants (citric acid and trisodium citrate), lemon juice, and L-ascorbic acid (final concentration 0.04% by mass) were added to each black tea extract adjusted to the tannin content (final concentration) shown in Table 9, and sodium bicarbonate was added to achieve the concentrations shown in Table 9, and sodium bicarbonate was added to adjust the pH to approximately 4.0. Each of these black tea extracts was filled into canned containers and retort sterilized (heat-pressure sterilization) under conditions equivalent to 124°C for 30 seconds to prepare the sample beverage of Test Example 27. In addition, a sample beverage of Test Example 26 was prepared as a control beverage, without the addition of either indole or nerolidol. The pH of each sample beverage after heat sterilization was measured using a pH meter, and all were approximately 4.0.

[0079] (2. Sensory Evaluation Test) For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 1 to assess the odor of heat degradation. For each sample black tea beverage, a sensory evaluation test was conducted using the same method as described in Test 2 to assess the flavor disharmony.

[0080] Table 9 shows the results of the sensory evaluation tests for the sample black tea beverages in Test Examples 26 and 27.

[0081]

[0082] The results in Table 9 show that even in tea beverages with an acidic pH and containing sucrose and fruit juice, indole and nerolidol have the effect of suppressing the odor caused by heat deterioration.

[0083] According to the present invention, it is possible to provide a packaged black tea beverage in which the flavor and aroma of the black tea beverage are maintained while the odor of heat degradation is suppressed, as well as a method for producing the same.

Claims

1. A packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, wherein at least one of the following conditions (i) and (ii) is met: (i) the indole content is 30 to 2000 ppb; (ii) the nerolidol content is 10 to 5000 ppb.

2. The packaged black tea beverage according to claim 1, satisfying both of the following conditions (i) and (ii). (i) The indole content is 30 to 2000 ppb. (ii) The nerolidol content is 10 to 5000 ppb.

3. A method for producing a packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, comprising preparing the packaged black tea beverage such that it satisfies at least one of the following conditions (i) and (ii): (i) the indole content is 30 to 2000 ppb; (ii) the nerolidol content is 10 to 5000 ppb.

4. A method for suppressing off-flavors due to heat deterioration in a packaged black tea beverage having a tannin content of 15 mg / 100 mL or more, while maintaining the flavor of the black tea beverage, comprising preparing the packaged black tea beverage such that it satisfies at least one of the following conditions (i) and (ii): (i) the indole content is 30 to 2000 ppb; (ii) the nerolidol content is 10 to 5000 ppb.

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