Sweetener taste improver, and food or beverage and flavor composition containing same

Abstract

The present invention provides a sweetener taste improver that helps the palatability of a food or beverage be maintained despite the sugar content being reduced and a high-intensity sweetener being used. The present invention relates to a sweetener taste improver containing one or more compounds selected from caffeoyl tryptophan and p-coumaroyl tryptophan, wherein the content of the one or more compounds is 2 mass% or more with respect to the dry solid content of the taste improver.

Description

Taste quality improving agent for sweeteners, food and drink containing the same, and flavor composition

[0001] The present invention relates to a taste quality improving agent for sweeteners containing one or more selected from caffeoyl tryptophan and p-coumaroyl tryptophan, as well as food and drink and a flavor composition containing the same.

[0002] Against the background of increasing health consciousness among consumers and the widespread recognition that obesity and overweight are social losses, products in which the sugar content in food and drink is reduced and sweetness is supplemented with high-intensity sweeteners have been launched on the market. While this is desirable for the purpose of preventing excessive calorie intake, there is a problem that the change in intensity and quality of sweetness impairs the deliciousness of products, making them less likely to be chosen by consumers, and as a result, they do not contribute to health as intended. The present invention improves the taste quality of sweeteners by using one or more selected from caffeoyl tryptophan and p-coumaroyl tryptophan, and the following documents are available regarding caffeoyl tryptophan and p-coumaroyl tryptophan. For example, Patent Document 1 describes that caffeoyl tryptophan is an astringent compound, and reducing this component is promising for reducing the astringent taste of products. In addition, Patent Document 2 describes that caffeoyl tryptophan and p-coumaroyl tryptophan are precursors of substances that cause musty odor, and reducing these can provide a coffee beverage with weak discomfort and suppressed musty odor. Further, Patent Document 3 describes a uric acid level reducing agent containing caffeoyl tryptophan as an active ingredient. As described above, there are no reports on the improvement of the taste quality of sweeteners by caffeoyl tryptophan and p-coumaroyl tryptophan.

[0003] International Publication No. WO 2020 / 212145 Japanese Unexamined Patent Application Publication No. 2008-5842 Japanese Unexamined Patent Application Publication No. 2021-14414

[0004] An object of the present invention is to provide a taste quality improving agent for sweeteners that contributes to not impairing the deliciousness of food and drink while reducing the amount of sugar used and using a high-intensity sweetener.

[0005] The present invention relates to the following [1] to [5]. [1] A sweetener flavor improver containing one or more compounds selected from caffeoyltryptophan and p-coumaroyltryptophan, wherein the content of the one or more compounds is 2% by mass or more relative to the dry solid content of the flavor improver. [2] The flavor improver according to [1], wherein the sweetener is sucrose. [3] The flavor improver according to [1] or [2] for improving sweetness intensity, improving the onset of sweetness, or improving mouthfeel. [4] A food or beverage containing the flavor improver according to any one of [1] to [3], wherein the content of the one or more compounds is 0.1 to 1000 ppt. [5] A flavor composition containing the flavor improver according to any one of [1] to [3].

[0006] The sweetener flavor modifier of the present invention contains one or more compounds selected from caffeoyltryptophan (hereinafter referred to as CaW) and p-coumaroyltryptophan (hereinafter referred to as p-CoW). CaW and p-CoW can be obtained by various means. For example, CaW can be obtained by amidating caffeic acid and tryptophan. Also, p-CoW can be obtained by amidating p-coumaric acid and tryptophan. For example, the desired flavor modifier can be obtained by amidating through a chemical reaction as described in PLOS ONE | DOI:10.1371 / journal.pone.0150392 March 17, 2016 and then purifying, or by amidating through an enzymatic reaction as described in Food Chemistry Volume 457, 1 November 2024, 140131 and then purifying. Furthermore, caffeoyltryptophan and p-coumaroyltryptophan have been reported to be present in various plants (e.g., Phytochemistry, 1987, 26, 4, 1195-1196; Bios., Biotech., and Biochem., 1995, 59, 10, 1887-1890; Nat. Prod. Sci., 2022, 28, 3; Jour. of Food Compos. and Anal., 2020, 86, 103363; Jour. of Food Compos. and Anal., 2016, 49, 65-77; Bio. Med. Research International, 2018, 6251546; Phytochemistry, 1995, 40, 5, 1577-1578; Food Chemistry, 2012). (132, 2, 841-848 and Tropical Jour. Of Pharmaceu. Res., 2019, 18, 3). These plants can also be obtained by extraction and purification. The aforementioned taste improver contains at least 2% by mass of one or more of the aforementioned compounds relative to the dry solid content of the taste improver. A higher content is advantageous in terms of the function and ease of use of the taste improver.The content of the one or more compounds is more preferably 5% by mass or more, even more preferably 10% by mass or more, and most preferably 30% by mass or more. When obtaining CaW and / or p-CoW from raw materials such as plants through extraction and purification, it is necessary to purify and reduce impurities so that the one or more compounds contained in the dry solid content are 2% by mass or more.

[0007] Examples of sweeteners whose taste quality is improved by the aforementioned taste-improving agent include sucrose, glucose, fructose, erythritol, xylitol, sorbitol, mannitol, trehalose, palatinose, mogroside, stevioside, glycyrrhizin, glycyrrhizic acid, aspartame, sucralose, acesulfame potassium, neotame, alitame, thaumatin, and neohesperidin dihydrochalcone. The aforementioned taste-improving agent is particularly effective in improving the taste quality of sucrose. The aforementioned taste-improving agent has a mass ratio of one or more compounds to the sweetener of 1 × 10⁻⁶. -10 : 1 to 1 x 10 -6 It is preferable to use it in the range of :1. The mass ratio is 1 × 10 -9 : 1 to 1 x 10 -7 : 1 is preferable.

[0008] The aforementioned taste-improving agent can be used to improve sweetness intensity, improve the onset of sweetness, or improve mouthfeel. In the present invention, "mouthfeel" refers to a sensation distinct from taste, aroma, and appearance (sight), and refers to the cutaneous sensation felt in the oral cavity, including the teeth and tongue, when food or beverages are ingested. More specifically in the present invention, it refers to sensations such as "mouthfeel," "tongue texture," "clinginess," "smoothness," "body," and "thickness." Furthermore, "improvement of mouthfeel" means strengthening (improving) the sensations of "mouthfeel," "tongue texture," "clinginess," "smoothness," "body," or "thickness" of the product.

[0009] The aforementioned flavor enhancer can be used by incorporating it into food and beverages. The food and beverage containing the flavor enhancer preferably contains the sweetener described above. The amount of the flavor enhancer in the food and beverage is preferably 0.1 to 1000 ppt, and more preferably 1 to 500 ppt. By incorporating the flavor enhancer into the food and beverage, the flavor quality of the sweetener in the food and beverage can be improved. In particular, it can improve the sweetness intensity, improve the onset of sweetness, or improve the mouthfeel. Examples of the aforementioned food and beverage include those containing sweeteners, such as low-fruit juice beverages, low-calorie beverages, sports drinks, carbonated beverages, alcoholic beverages, non-alcoholic beverages, energy drinks, green tea, black tea, oolong tea, coffee, lactic acid bacteria beverages, vegetable juices, soups, dressings, curries, stews, hard candies, soft candies, sugar-free candies, gum, tablets, gummies, and snack foods.

[0010] The aforementioned flavor enhancer can be used by incorporating it into a flavor composition. The flavor composition may contain known flavors and / or conventional additives within a quantitative or qualitative range that does not impair the objectives of the present invention. As the flavor, synthetic flavors, various natural flavors such as natural essential oils, spice extracts, etc., that can be used in food and beverages can be arbitrarily used. As the additive, there is no particular limit as long as it can be used in food and beverages. For example, conventional solvents used in flavor compositions include water, ethanol, propylene glycol, edible oils and fats, 1-propanol, 2-propanol, etc. The flavor composition can be used by incorporating it into the food and beverage, similar to the aforementioned flavor enhancer. The food and beverage containing the flavor composition preferably contains the above-mentioned sweetener. By incorporating the flavor composition into the food and beverage, the flavor quality of the sweetener in the food and beverage can be improved. In particular, the sweetness intensity can be improved, the onset of sweetness can be improved, or the mouthfeel can be improved.

[0011] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, "%" is based on mass.

[0012] 1. Analysis Method for Target Components: CaW and p-CoW were detected and quantified by high-performance liquid chromatography. In this analysis, CaW eluted at a retention time of 24.6 min, and p-CoW eluted at a retention time of 25.2 min. High-performance liquid chromatograph: Agilent 1260 Infinity II LC (Agilent Technologies, Inc.) Column: COSMOSIL 3C18-AR-II (2.0 mm inner diameter, 150 mm length, Nacalai Tesque Co., Ltd.) Column temperature: 40°C Mobile phase: Purified water containing 0.1 vol. formic acid: Acetonitrile containing 0.1 vol. formic acid = 91:9 (0-15 min, isocratic elution), 91:9 → 0:100 (15-30 min, gradient elution), 0:100 (30-40 min, isocratic elution) Flow rate: 0.25 ml / min Detection: Ultraviolet spectrophotometer: 325 nm

[0013] 2. Preparation of a Taste-Enhancing Agent by Chemical Synthesis (Synthesis of CaW) Based on the literature (PLOS ONE | DOI:10.1371 / journal.pone.0150392 March 17, 2016), CaW was synthesized using the following procedure. Caffeic acid (183.9 mg) was dissolved in dimethyl sulfoxide (11.2 g). While stirring this solution, N,N'-dicyclohexylcarbodiimide (309 mg) was added little by little. Next, L-tryptophan (206 mg) was added, and the mixture was stirred at room temperature for 18 hours to obtain the reaction solution. Analysis of the reaction solution using the analytical method described above revealed a peak for CaW.

[0014] Fraction 1 (Liquid-Liquid Extraction): The reaction mixture was transferred to a separatory funnel, and ethyl acetate (100 ml) and purified water (100 ml) were added and separated. To the separated aqueous layer, another 100 ml of ethyl acetate was added and separated again. The two ethyl acetate layers were then combined and the solvent was removed by vacuum concentration. Subsequently, the following two-step purification was performed using high-performance liquid chromatography.

[0015] Fraction 2 (High-Performance Liquid Chromatography Fraction 1) Elutions containing CaW with retention times of 56–62 min were separated by high-performance liquid chromatography. High-performance liquid chromatograph: Automated preparative HPLC system PLC761 (GL Sciences Co., Ltd.) Column: Inertsil ODS-3 (20 mm inner diameter, 250 mm length, GL Sciences Co., Ltd.) Column temperature: 40°C Mobile phase: Purified water containing 0.1 vol% formic acid: Acetonitrile containing 0.1 vol% formic acid = 97:3 → 3:97 (0–90 min, gradient elution), 3:97 (90–100 min, isocratic elution) Flow rate: 5.0 ml / min Detection: Ultraviolet spectrophotometer: 320 nm

[0016] Fraction 3 (High-Performance Liquid Chromatography Fraction 2) A single peak of CaW eluted at a retention time of 33-34 min was isolated by high-performance liquid chromatography. High-performance liquid chromatograph: Automated preparative HPLC system PLC761 (GL Sciences Co., Ltd.) Column: Inertsil ODS-3 (20 mm inner diameter, 250 mm length, GL Sciences Co., Ltd.) Column temperature: 40°C Mobile phase: Purified water containing 0.1 vol% formic acid: Acetonitrile containing 0.1 vol% formic acid = 65:35 (0-50 min, isocratic elution), 3:97 (50-70 min, isocratic elution) Flow rate: 5.0 ml / min Detection: Ultraviolet spectrophotometer: 320 nm

[0017] Following the above procedure, 4.6 mg of the purified product was obtained. The chemical shift of the NMR spectrum of the purified product showed good agreement with the value reported in the literature (Biosscience, Biotechnology, and Biochemistry, 1995, 59, 10, 1887-1890), and it was determined that CaW was obtained as the purified product. Furthermore, the purity of the purified product was determined to be 95% or higher from the area value in the HPLC chromatogram. A propylene glycol solution containing 3.33 ppm of this purified component was prepared. This solution is referred to as the solution in Example 1-1.

[0018] Evaluation of Sweetness Improvement "Rose Brand Granulated Sugar" (DM Mitsui Sugar) was dissolved in deionized water to prepare a 4% sucrose aqueous solution and a 5% sucrose aqueous solution (positive control). The 4% sucrose aqueous solution with 100 ppm of propylene glycol added was designated as the control, and the solution from Example 1-1 with 100 ppm of propylene glycol added was designated as Example 1-1-1. The sweetness of the control, Example 1-1-1, and positive control was evaluated. Number of evaluators: 12. Evaluation method: The "intensity of sweetness," "speed of sweetness onset," and "body of sweetness" of the control were assigned a score of 4 points, and the sweetness of Example 1-1-1 and the positive control were relatively evaluated on a 7-point scale from 1 to 7. A score closer to 7 indicates a better evaluation, while a score closer to 1 indicates a less favorable evaluation. Specifically, "sweetness intensity" means that the closer to 7 points the sweeter the taste, and the closer to 1 point the sweeter the taste, the weaker the taste; "speed of sweetness onset" means that the closer to 7 points the sweeter the taste, and the closer to 1 point the slower the taste; and "sweetness body" means that the closer to 7 points the sweeter the taste has more body, and the closer to 1 point the sweeter the taste is thinner. The average scores are shown in Table 1. In Examples 1-2, in which CaW was added, we observed characteristics such as increased sweetness intensity, faster sweetness onset, increased sweetness body, and a closer approach to positive control.

[0019]

[0020] 3. Preparation of a Taste Improvement Agent by Chemical Synthesis (Synthesis of p-CoW) Based on the literature (PLOS ONE | DOI:10.1371 / journal.pone.0150392 March 17, 2016), p-CoW was synthesized using the following procedure. p-coumaric acid (329.7 mg) was dissolved in dehydrated dimethyl sulfoxide (22.25 g). While stirring this solution, N,N'-diisopropylcarbodiimide (281.9 mg) was added little by little. Then, L-tryptophan (421.5 mg) was added. This solution was stirred at room temperature for 32 hours, and after stopping stirring, it was allowed to stand for another 7 days to obtain the reaction solution. Analysis of the reaction solution using the analytical method described above revealed the presence of a p-CoW peak.

[0021] Fraction 1 (Liquid-Liquid Extraction): The reaction mixture was transferred to a separatory funnel, and ethyl acetate (200 ml) and purified water (200 ml) were added and separated. Fresh ethyl acetate (200 ml) was added to the separated aqueous layer, and after separation, the two ethyl acetate layers were combined and the solvent was removed by vacuum concentration. Next, purification was performed by high-performance liquid chromatography under the same conditions as for CaW.

[0022] Fraction 2 (High-Performance Liquid Chromatography Fraction 1): Under the conditions of Fraction 2 described above, eluates containing p-CoW with a retention time of 59-65 min were collected by high-performance liquid chromatography.

[0023] Fraction 3 (High-Performance Liquid Chromatography Fraction 2) Under the conditions of Fraction 3 described above, a single peak of p-CoW eluted at a retention time of 40-47 min was isolated by high-performance liquid chromatography. Recovered fraction:

[0024] Following the above procedure, 10.5 mg of the purified product was obtained. The chemical shift of the NMR spectrum of the purified product showed good agreement with the value reported in the literature (Biosscience, Biotechnology, and Biochemistry, 1995, 59, 10, 1887-1890), and it was determined that p-CoW was obtained as the purified product. Furthermore, the purity of the purified product was determined to be 95% or higher from the area value in the HPLC chromatogram. A propylene glycol solution containing 3.81 ppm of this purified component was prepared. This solution is used as the solution in Example 2-1.

[0025] Evaluation of Sweetness Improvement "Rose Brand Granulated Sugar" (DM Mitsui Sugar) was dissolved in deionized water to prepare a 4% sucrose aqueous solution and a 5% sucrose aqueous solution (positive control). The 4% sucrose aqueous solution with 100 ppm of propylene glycol added was designated as the control, and the solution from Example 2-1 with 100 ppm of propylene glycol added was designated as Example 2-1-1. The sweetness of the control, Example 2-1-1, and positive control was evaluated. Number of evaluators: 12 Evaluation method: The "intensity of sweetness," "speed of sweetness onset," and "body of sweetness" of the control were assigned a score of 4, and the sweetness of Example 2-1-1 and the positive control was relatively evaluated on a 7-point scale from 1 to 7. The meaning of the evaluation points is the same as described above. The average values ​​of the evaluation points are shown in Table 2. In Example 2-1-1, to which p-CoW was added, the intensity of sweetness increased, the body of sweetness increased, and it was observed to approach the characteristics of the positive control.

[0026]

[0027] 4. Preparation of a flavor enhancer from instant coffee In the subsequent examples, the components contained in the extract were quantified using a calibration curve created with the synthesized CaW and p-CoW described above. Instant coffee made from dark-roasted Canephora coffee beans (Dan Kaffe (Malaysia) Sdn Bhd) contained 0.056% CaW and 0.026% p-CoW in its dried powder. 2 g of this instant coffee was mixed with deionized water to prepare a 2000 g aqueous solution. The aqueous solution was passed through an Ultrafilter Q0500 090E (Advantec Toyo Co., Ltd.) to obtain a pass-through portion mainly containing low molecular weight components with a molecular weight of 50,000 or less, and a non-pass-through portion mainly containing high molecular weight components with a molecular weight of 50,000 or more. The pass-through portion contained 0.066% CaW and 0.031% p-CoW in 1.7 g of dry weight. In the non-pass portion (dry weight 0.3 g), CaW and p-CoW were outside the detection limit (less than 0.01%).

[0028] Fraction 1 (Liquid-Liquid Extraction): Purified water (60 g) and ethyl acetate (60 g) were added to the dried passage and separated. New ethyl acetate (60 g) was added to the separated aqueous layer, and after separation, both the ethyl acetate layer and the aqueous layer were combined. The solvent was removed from both the ethyl acetate layer and the aqueous layer by vacuum concentration and freeze-drying. The ethyl acetate layer contained 0.52% CaW and 0.25% p-CoW per 0.2 g dry weight. In the aqueous layer (1.5 g dry weight), CaW and p-CoW were outside the detection limit (less than 0.01%). Next, the ethyl acetate layer was further purified by high-performance liquid chromatography under the same conditions as for CaW.

[0029] Fraction 2 (High-Performance Liquid Chromatography Fraction 1): Under the conditions of Fraction 2 described above, high-performance liquid chromatography was performed to collect eluates with retention times of 56 to 65 minutes in which CaW and p-CoW were eluted.

[0030] Fraction 3 (High-Performance Liquid Chromatography Fraction 2) Under the conditions of Fraction 3 described above, high-performance liquid chromatography was used to isolate the peaks of CaW that elute at a retention time of 33-34 min and p-CoW that elute at a retention time of 40-47 min.

[0031] Following the above procedure, a CaW purified product of 1.4 mg dry weight (referred to as the purified product of Example 3-1) and a p-CoW purified product of 1.6 mg dry weight (referred to as the purified product of Example 3-2) were obtained. From quantitative results using a calibration curve, the CaW content of the purified product of Example 3-1 was 71.4% by dry weight, and the p-CoW content of the purified product of Example 3-2 was 29.3% by dry weight.

[0032] A propylene glycol solution containing 47.6 ppm of instant coffee used in the evaluation fraction for sweetness improvement (Comparative Example 3-1), a propylene glycol solution containing 40.4 ppm of the pass-through portion (Comparative Example 3-2), a propylene glycol solution containing 7.1 ppm of the non-pass-through portion (Comparative Example 3-3), a propylene glycol solution containing 4.7 ppm of the ethyl acetate layer (Comparative Example 3-4), a propylene glycol solution containing 35.7 ppm of the aqueous layer (Comparative Example 3-5), a propylene glycol solution containing 0.033 ppm of the purified product from Example 3-1 (Example 3-1-1), and a propylene glycol solution containing 0.038 ppm of the purified product from Example 3-2 (Example 3-2-1) were prepared. An aqueous solution containing 0.03% Rebaudioside A (Ingredion Japan) was prepared. A control was prepared by adding 100 ppm of propylene glycol to this aqueous solution, and comparative examples 3-1, 3-2, 3-3, 3-4, and 3-5 at 100 ppm each were added to the same aqueous solution. Samples of examples 3-1-1 and 3-2-1 at 100 ppm each were also prepared, and their sweetness was evaluated. Number of evaluators: 6 Evaluation method: The "intensity of sweetness," "speed of sweetness onset," and "body of sweetness" of the control were evaluated on a 7-point scale from 1 to 7 in absolute terms, while the sweetness of the comparative examples and examples was evaluated on a 7-point scale from 1 to 7 in relative terms. The meaning of the evaluation points is the same as described above. The average values ​​of the evaluation points are shown in Table 3-1. Examples 3-1-1 and 3-2-1 showed enhanced sweetness, improved speed of sweetness onset, and enhanced body. p-CoW, in particular, showed a favorable effect. On the other hand, no significant differences were observed in each evaluation item for the comparative examples. In particular, the aqueous solutions containing Comparative Examples 3-3 and 3-5, which did not contain CaW and p-CoW, showed little difference from the control.

[0033]

[0034] Evaluation of sweetness improvement A propylene glycol solution containing 6.7 ppm of the purified product of Example 3-1 (Example 3-1-2), a propylene glycol solution containing 5.9 ppm of the purified product of Example 3-2 (Example 3-2-2), and a propylene glycol solution containing 6.7 ppm of the purified product of Example 3-1 and 5.9 ppm of the purified product of Example 3-2 (Example 3-3) were prepared. An aqueous solution containing 2% "Rose Brand Granulated Sugar," 0.02% monosodium glutamate, and 0.001% sodium inosinate / sodium guanylate was prepared. A control was prepared by adding 100 ppm of propylene glycol to this aqueous solution, and samples were prepared by adding 100 ppm of Examples 3-1-2, 3-2-2, and 3-3 to the same aqueous solution, and their sweetness was evaluated. Number of evaluators: 14 Evaluation method: The control was scored on 4 points for "intensity of sweetness," "speed of sweetness onset," "body of sweetness," "intensity of umami," "speed of umami onset," and "persistence of umami," and the sweetness and umami of the examples were relatively evaluated on a 7-point scale from 1 to 7. The meaning of the evaluation points is the same as described above. The average values ​​of the evaluation points are shown in Table 3-2. Examples 3-1-2, 3-2-2, and 3-3 showed an increase in sweetness, an improvement in the speed of sweetness onset, and an increase in body. In particular, conditions combining CaW and p-CoW showed a more favorable effect, and improvements were observed not only in sweetness but also in umami intensity and umami persistence.

[0035]

[0036] 5. Preparation of a flavor enhancer from unused resources (coffee extraction residue) 59 g of extraction residue (moisture content 30%) from roasted Canephora coffee beans used in the production of coffee extract was mixed with 89 g of a 30% by weight ethanol aqueous solution, and stirred extraction was carried out at 25°C for 9 hours. The residue and insoluble matter were filtered off using filter paper to obtain 89.6 g of extract. After solvent removal by vacuum concentration and freeze-drying, the dry weight of the extract was 0.4 g. This solid content contained 0.054% CaW and 0.062% p-CoW.

[0037] Fraction 2 (High-Performance Liquid Chromatography Fraction 1): Since the extract derived from the extraction residue had a low content of water-soluble components, Fraction 1 was omitted, and the extract was then subjected to high-performance liquid chromatography. Under the conditions of Fraction 2, high-performance liquid chromatography was performed to collect eluates with retention times of 56 to 65 minutes in which CaW and p-CoW were eluted.

[0038] Fraction 3 (High-Performance Liquid Chromatography Fraction 2) Under the conditions of Fraction 3 described above, high-performance liquid chromatography was used to isolate the peaks of CaW that elute at a retention time of 33-34 min and p-CoW that elute at a retention time of 40-47 min.

[0039] Following the above procedure, a CaW purified product of 0.3 mg dry weight (referred to as the purified product of Example 4-1) and a p-CoW purified product of 0.3 mg dry weight (referred to as the purified product of Example 4-2) were obtained. The CaW content of the purified product of Example 4-1 was 58.7% by dry weight, and the p-CoW content of the purified product of Example 4-2 was 66.7% by dry weight.

[0040] Evaluation of sweetness improvement A 30 wt% aqueous ethanol solution containing 8 ppm of an extract obtained by extracting the aforementioned coffee extraction residue with a 30 wt% aqueous ethanol solution (Comparative Example 4-1), a 30 wt% aqueous ethanol solution containing 0.006 ppm of the purified product of Example 4-1 (Example 4-1-1), a 30 wt% aqueous ethanol solution containing 0.006 ppm of the purified product of Example 4-2 (Example 4-2-1), and a 30 wt% aqueous ethanol solution containing 0.006 ppm of the purified product of Example 4-1 and 0.006 ppm of the purified product of Example 4-2 (Example 4-3) were prepared. An aqueous solution containing 0.013% sucralose (Tsurya Kasei Kogyo Co., Ltd.) was prepared. A product obtained by adding 1000 ppm of a 30 wt% aqueous ethanol solution to this aqueous solution was used as a control, and products obtained by adding 1000 ppm of Comparative Example 4-1, Examples 4-1-1, 4-2-1, and 4-3 to the same aqueous solution were prepared, and their sweetness was evaluated. Number of evaluators: 11 Evaluation method: The "sweetness intensity", "sweetness onset speed", and "sweetness body feel" of the control were absolutely evaluated on a 7-level scale from 1 to 7, and the sweetness of Comparative Examples and Examples was relatively evaluated on a 7-level scale from 1 to 7. The meaning of the evaluation scores is the same as described above. The average values of the evaluation scores are shown in Table 4. In Examples 4-1-1, 4-2-1, and 4-3, enhancement of sweetness, improvement of sweetness onset speed, and enhancement of body feel were recognized. In particular, more favorable effects were exhibited under the conditions where p-CoW, or CaW and p-CoW were combined. On the other hand, in the Comparative Example, no significant difference was recognized for each evaluation item.

[0041]

[0042] 6. Preparation of taste quality improver from unused resource (Canephora species silver skin) To 18.2 g of thin skin (silver skin) separated and recovered during roasting of green Canephora species coffee beans, 183 g of methanol was added, and extraction was performed by stirring at 25°C for 9 hours. The residue and insoluble matter were filtered off using filter paper, and 133 g of extract was obtained. The solvent was distilled off by concentration under reduced pressure and freeze-drying, and as a result, the dry weight of the extract was 1.3 g. This solid content contained 0.031% of CaW and 0.014% of p-CoW.

[0043] Fraction 1 (liquid-liquid extraction) Purified water (50 g) and ethyl acetate (50 g) were added to the dried extract, followed by liquid separation. Fresh ethyl acetate (50 g) was added to the separated aqueous layer, and after liquid separation, the two portions of both the ethyl acetate layer and the aqueous layer were combined. The solvent was distilled off from both the ethyl acetate layer and the aqueous layer by concentration under reduced pressure and freeze-drying. The ethyl acetate layer, having a dry weight of 0.14 g, contained 0.23% of CaW and 0.12% of p-CoW. The aqueous layer had a dry weight of 1.0 g, and CaW and p-CoW were below the detection limit (less than 0.01%). Subsequently, further purification of the ethyl acetate layer was performed by high performance liquid chromatography.

[0044] Fraction 2 (first fractionation by high performance liquid chromatography) An eluate corresponding to a retention time of 56 to 65 minutes at which CaW and p-CoW are eluted was fractionated by high performance liquid chromatography under the conditions for Fraction 2.

[0045] Fraction 3 (second fractionation by high performance liquid chromatography) By high performance liquid chromatography under the conditions for the aforementioned Fraction 3, the peak of CaW eluted at a retention time of 33 to 34 minutes and the peak of p-CoW eluted at a retention time of 40 to 47 minutes were fractionated.

[0046] By the above procedure, a purified CaW product having a dry weight of 0.41 mg (referred to as the purified product of Example 5-1) and a purified p-CoW product having a dry weight of 0.18 mg (referred to as the purified product of Example 5-2) were obtained. The CaW content in the dry weight of the purified product of Example 5-1 was 70.6%, and the p-CoW content in the dry weight of the purified product of Example 5-2 was 76.2%.

[0047] Evaluation of sweetness improvement A 92.4% by weight ethanol aqueous solution containing 10 ppm of the extract obtained by extracting the coffee silver skin with methanol was prepared (Comparative Example 5-1), a 92.4% by weight ethanol aqueous solution containing 0.003 ppm of the purified product of Example 5-1 was prepared (Example 5-1-1), a 92.4% by weight ethanol aqueous solution containing 0.0013 ppm of the purified product of Example 5-2 was prepared (Example 5-2-1), and a 92.4% by weight ethanol aqueous solution containing 0.003 ppm of the purified product of Example 5-1 and 0.0013 ppm of the purified product of Example 5-2 was prepared (Example 5-3). An aqueous solution was prepared by adding water to 75 g of "Tsuyu no Moto (3x concentrated)" (Ninben Co., Ltd.) to make 1500 g. A control solution was prepared by adding 2000 ppm of 92.4% by weight ethanol to this aqueous solution. Comparative examples 5-1, 5-1-1, 5-2-1, and 5-3 were prepared by adding 2000 ppm of each to the same aqueous solution, and their sweetness was evaluated. Number of evaluators: 9 Evaluation method: The control solution was scored on 4 points for "intensity of sweetness," "speed of sweetness onset," "body of sweetness," "intensity of umami," "speed of umami onset," and "sustainability of umami." The sweetness and umami of the comparative examples and examples were then relatively evaluated on a 7-point scale from 1 to 7. The meaning of the evaluation points is the same as described above. The average values ​​of the evaluation points are shown in Table 5. Examples 5-1-1, 5-2-1, and 5-3 showed enhanced sweetness, improved speed of sweetness onset, and enhanced body. In particular, the combination of CaW and p-CoW showed more favorable effects, and improvements were observed not only in sweetness but also in the intensity and duration of umami. On the other hand, in the comparative example, no significant differences from the control were observed for each evaluation item.

[0048]

[0049] 7. Preparation of a flavor enhancer from unused resources (Arabica silverskin) 186 g of silverskin, the thin skin separated and recovered during the roasting of Arabica coffee beans, was mixed with 1890 g of methanol and extracted by stirring at 25°C for 6 hours. The residue and insoluble matter were filtered off using filter paper to obtain 1400 g of extract. After solvent removal by vacuum concentration and freeze-drying, the dry weight of the extract was 12 g. This solid content contained 0.011% CaW. p-CoW was outside the detection limit (less than 0.01%).

[0050] Fraction 1 (Liquid-Liquid Extraction): Purified water (300 g) and ethyl acetate (300 g) were added to the dried extract and separated. Further separation was performed by adding ethyl acetate (300 g) to the aqueous layer. Both the ethyl acetate layer and the aqueous layer were then combined. The solvent was removed from both the ethyl acetate layer and the aqueous layer by vacuum concentration and freeze-drying. The ethyl acetate layer contained 0.091% CaW per 1.2 g dry weight. p-CoW was outside the detection limit (less than 0.01%). The aqueous layer was 10 g dry weight, and both CaW and p-CoW were outside the detection limit (less than 0.01%). The ethyl acetate layer was then further purified by high-performance liquid chromatography.

[0051] Fraction 2 (High-Performance Liquid Chromatography Fraction 1): Under the conditions of Fraction 2, high-performance liquid chromatography was performed to collect the eluate with a retention time of 56–65 min at which CaW eluted. No p-CoW peak was detected.

[0052] Fraction 3 (High-Performance Liquid Chromatography Fraction 2): Under the conditions of Fraction 3 described above, the CaW peak eluted at a retention time of 33-34 min was isolated by high-performance liquid chromatography. No p-CoW peak was detected.

[0053] By following the above procedure, a CaW purified product with a dry weight of 0.85 mg (referred to as the purified product of Example 6-1) was obtained. The CaW content of the purified product of Example 6-1 was 88.7% by dry weight.

[0054] For the evaluation of sweetness improvement, a propylene glycol solution containing 1 ppm of Example 6-1 (Example 6-2) and a propylene glycol solution containing 0.01 ppm (Example 6-3) were prepared. Diluted fruit juice was prepared by adding water to 500 g of "Apple 100%" (Tomoe Dairy Co., Ltd.) to make 1500 g. A control was prepared by adding 1000 ppm of propylene glycol to this diluted fruit juice, and then adding 1000 ppm (Example 6-2-1), 100 ppm (Example 6-2-2), and 10 ppm (Example 6-2-3) of Example 6-2 to the same diluted fruit juice, and 100 ppm (Example 6-3-1) and 10 ppm (Comparative Example 6-1) of Example 6-3 were added to the same diluted fruit juice, and the sweetness of each was evaluated. Number of evaluators: 8 Evaluation method: The "intensity of sweetness," "speed of sweetness onset," and "body of sweetness" of the control were assigned a score of 4, and the sweetness of the comparative example and example was relatively evaluated on a 7-point scale from 1 to 7. The meaning of the evaluation points is the same as described above. The average values ​​of the evaluation points are shown in Table 6. Examples 6-2-1, 6-2-2, 6-2-3, and 6-3-1 showed an increase in sweetness, an improvement in the speed of sweetness onset, and an increase in body. On the other hand, in comparative example 6-1, the degree of improvement in each evaluation item was small, and no significant difference from the control could be observed.

[0055]

Claims

1. A sweetener flavor enhancer containing one or more compounds selected from caffeoyltryptophan and p-coumaroyltryptophan, wherein the content of the one or more compounds is 2% by mass or more relative to the dry solid content of the flavor enhancer.

2. The taste-improving agent according to claim 1, wherein the sweetener is sucrose.

3. A taste quality improving agent according to claim 1 or 2, for improving sweetness intensity, improving the onset of sweetness, or improving mouthfeel.

4. A food or beverage containing a flavor-improving agent according to any one of claims 1 to 3, wherein the content of one or more of the compounds is 0.1 to 1000 ppt.

5. A flavor composition containing the flavor-improving agent described in any one of claims 1 to 3.

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