Citral deterioration inhibitor and food containing the same

Abstract

To provide a citral deterioration inhibitor that can suppress generation of off-flavors by suppressing deterioration of citral to suppress formation of p-methylacetophenone and p-cresol from citral without impairing the original taste of foods, and to provide a citral-containing food in which deterioration of citral is suppressed.SOLUTION: There is provided a method for producing a citral deterioration inhibitor, wherein the citral deterioration inhibitor comprises catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene, the total content of catechin and epigallocatechin is 128 to 570 ppm, and (catechin+epigallocatechin) / (p-mentha-1,5,8-triene+p-mentha-1,3,8-triene) (weight ratio) is 15 to 1400. The method for producing a citral deterioration inhibitor comprises a step of subjecting lemon myrtle to a pulse electric field treatment under the conditions of specific energy 0.005 to 1110 kJ / kg, electric field strength 3 to 55 kV / cm, and pulse width 500 to 40000 ns, subsequently performing an extraction treatment.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a citral deterioration inhibitor and a food containing the same.

Background Art

[0002] Citral is a flavor component contained in herbs and citrus fruits, and has a strong citrus-like flavor, so it is used as a flavor material for creating citrus-based flavors. However, citral is extremely unstable to heat and light, and easily deteriorates into substances that cause off-flavors such as odd odors, modified odors, or malodors. As representative substances causing the aforementioned off-flavors, p-methylacetophenone and p-cresol are known, and suppressing the production of these substances has been a long-standing challenge.

[0003] Patent Document 1 discloses a method of suppressing the production of p-cresol by incorporating an antioxidant component and a transition metal ion into a product containing citral, and describes that epigallocatechin, epigallocatechin gallate, gallic acid, quercitrin, and ascorbic acid are preferred as the aforementioned antioxidant component.

[0004] Further, Non-Patent Document 1 describes that the production of p-methylacetophenone is suppressed by either the sole addition of catechin or the sole addition of epigallocatechin.

[0005] However, since the aforementioned catechin and epigallocatechin exhibit a unique strong flavor, all of the above methods impair the original flavor of food, particularly when added to foods with mild flavors, or when added in an amount equal to or more than a certain level to enhance the effect.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Non-Patent Documents

[0007] [Non-Patent Document 1] 2015 Doctoral Dissertation, Chubu University, Hisao Ueno, pp. 13-24 [Overview of the project] [Problems that the invention aims to solve]

[0008] In light of the above circumstances, we have been investigating methods to suppress the generation of off-flavor-causing substances such as p-methylacetophenone and p-cresol in foods containing citral without impairing the original flavor of the food.Therefore, the object of the present invention is to provide a citral deterioration inhibitor that can suppress the generation of off-flavors by suppressing the deterioration of citral and inhibiting the generation of p-methylacetophenone and p-cresol from citral without impairing the original flavor of the food, and a citral-containing food in which the deterioration of citral is suppressed. [Means for solving the problem]

[0009] The inventors of the present invention conducted extensive research to solve the above problems and found that by adding a citral deterioration inhibitor, in which the total content of catechin and epigallocatechin is within a specific range and the ratio of the total amount of catechin and epigallocatechin to the total amount of p-mentha-1,5,8-triene and p-mentha-1,3,8-triene is within a specific range, to a food containing citral, the generation of p-methylacetophenone and p-cresol from citral is suppressed without impairing the original flavor of the food, thereby suppressing the generation of off-flavors. This led to the completion of the present invention.

[0010] That is, the first aspect of the present invention relates to a method for producing a citral degradation inhibitor, wherein the citral degradation inhibitor contains catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene, the total content of catechin and epigallocatechin is 128 to 570 ppm, and the (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) is 15 to 1400, and the method for producing a citral degradation inhibitor comprises the step of pulse electric field treatment of lemon myrtle under conditions of specific energy 0.005 to 1110 kJ / kg, electric field strength 3 to 55 kV / cm, and pulse width 500 to 40000 ns, followed by an extraction treatment. The second aspect of the present invention relates to a citral degradation inhibitor containing catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene, wherein the total content of catechin and epigallocatechin is 128 to 570 ppm, and the (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) is 15 to 1400. A preferred embodiment is the citral degradation inhibitor further containing 2-ethylidene-6-methyl-3,5-heptadienal, wherein the (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) / 2-ethylidene-6-methyl-3,5-heptadienal (weight ratio) is 2 to 9. A more preferred embodiment is the citral degradation inhibitor in which catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene are extracts derived from lemon myrtle. A further preferred embodiment is the citral degradation inhibitor in which the lemon myrtle-derived extract is obtained by pulsed electric field treatment of lemon myrtle under conditions of specific energy 0.005 to 1110 kJ / kg, electric field strength 3 to 55 kV / cm, and pulse width 500 to 40000 ns, followed by extraction.The third aspect of the present invention relates to a food product containing catechin, epigallocatechin, p-mentha-1,5,8-triene, p-mentha-1,3,8-triene, and citral, wherein the total content of catechin and epigallocatechin is 0.005 to 50 ppm, the (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) is 15 to 1400, and the citral content is 1 to 100 ppm. A preferred embodiment is the food product containing 50 to 2000 ppm of the citral deterioration inhibitor. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a citral degradation inhibitor that suppresses the degradation of citral without impairing the original flavor of the food, and suppresses the generation of p-methylacetophenone and p-cresol from citral, thereby suppressing the generation of off-flavors, as well as a citral-containing food in which the degradation of citral is suppressed. [Modes for carrying out the invention]

[0012] The present invention will be described in further detail below. The citral deterioration inhibitor of the present invention contains specific amounts of catechin, epigallocatechin, p-mentha-1,5,8-triene (chemical name in English: 1,5,8-p-Menthatriene) and p-mentha-1,3,8-triene (chemical name in English: 1,3,8-p-Menthatriene). This citral deterioration inhibitor can be used as an additive to foods containing citral, and by adding a specific amount to the food, the formation of p-methylacetophenone and p-cresol from citral can be suitably suppressed.

[0013] The aforementioned catechin refers to a type of flavonoid with CAS number 154-23-4 and the English chemical name (+)-Catechin. The aforementioned epigallocatechin refers to a substance with CAS number 970-74-1 and the English chemical name (-)-Epigallocatechin.

[0014] The total content of catechin and epigallocatechin in the citral deterioration inhibitor is preferably 128 to 570 ppm, more preferably 138 to 550 ppm, even more preferably 195 to 530 ppm, and particularly preferably 270 to 530 ppm. If the total content of catechin and epigallocatechin is less than 128 ppm, the effect of suppressing citral deterioration may not be obtained, and if it is more than 570 ppm, the original flavor of the food may be impaired.

[0015] In the citral deterioration inhibitor described above, the weight ratio of (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) is preferably 15 to 1400, more preferably 15 to 1000, even more preferably 15 to 650, and particularly preferably 17 to 440. If the weight ratio is less than 15, the masking effect against the strong flavors characteristic of catechin and epigallocatechin may plateau, and if it is greater than 1400, the masking effect against the strong flavors characteristic of catechin and epigallocatechin may not be sufficiently exerted, and the original flavor of the food may be impaired.

[0016] Preferably, the citral degradation inhibitor further contains 2-ethylidene-6-methyl-3,5-heptadienal (chemical name in English: 3,5-Heptadienal,2-ethylidene-6-methyl).

[0017] From the viewpoint of having a higher masking effect against the strong flavors characteristic of catechins and epigallocatechins, and allowing the original flavor of the food to be more fully appreciated, it is preferable that the (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) / 2-ethylidene-6-methyl-3,5-heptadienal (by weight) be contained in a range of 2 to 9, with 3.5 to 9 being more preferable, and 6 to 9 being even more preferable.

[0018] Examples of the method for measuring the contents of catechin and epigallocatechin in the citral deterioration inhibitor and the food include liquid chromatography-mass spectrometry and the like. Specifically, the sample solution may be appropriately diluted with methanol and then subjected to LC / MS / MS analysis. The measurement conditions at that time are as follows.

[0019] [LC / MS / MS Operating Conditions] (HPLC Conditions) Apparatus: Nexera system manufactured by Shimadzu Corporation Column: ACQUITY UPLC BEH C18, 2.1×100 mm, 1.7 μm (manufactured by Waters) Mobile phase: (A) Aqueous solution containing 0.1% formic acid, (B) Acetonitrile containing 0.1% formic acid Flow rate: 0.3 mL / min Column temperature: 35°C

[0020] (MS / MS Conditions) Apparatus: "QTRAP 5000" manufactured by AB SCIEX Ionization method: Electrospray ionization method (negative ion detection mode) Monitoring ions: Catechin; 289.0→109.0 (Da) Epigallocatechin; 305.0→125.0 (Da)

[0021] Further, examples of the method for measuring the contents of the citral, the p-methylacetophenone, the p-cresol, the 2-ethylidene-6-methyl-3,5-heptadienal, the p-mentha-1,5,8-triene, and the p-mentha-1,3,8-triene include gas chromatography-mass spectrometry (GC / MS) and the like. Specifically, an internal standard substance may be appropriately mixed with the sample solution, the peak area ratio of each component to the internal standard substance is calculated by dynamic headspace (DHS)-GC / MS analysis, and then analysis is performed by GC / MS. The measurement conditions at that time are as follows.

[0022] [GC / MS Operating Conditions] (Pretreatment Conditions) Equipment: GERSTEL "MPS2-XT" Heating time / temperature: 40℃ / 5 minutes Collection tube: Tenax TA Internal standard substance: o-cresol-d8

[0023] (GC / MS conditions) Equipment: Agilent Technologies 7890A, Agilent Technologies 5975C Inert Column: DB-WAX

[0024] The catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene are preferably extracts derived from lemon myrtle, as their content can be easily adjusted. Lemon myrtle is a species of plant belonging to the Myrtaceae family, native to Australia, and its scientific name is Backhousia citriodora.

[0025] To obtain the aforementioned lemon myrtle extract, for example, the lemon myrtle can be extracted using a solvent. Any method usable in the food industry can be used for solvent extraction, such as extraction by pulsed electric field treatment, extraction with stirring while heating, or reflux extraction. Pulsed electric field treatment is particularly preferred from the viewpoint of extraction efficiency.

[0026] The aforementioned pulsed electric field treatment refers to a treatment method that involves exposing a sample to an electric field generated by a pulsed voltage applied between a pair of electrodes, thereby altering the properties of cells in the sample.

[0027] As the solvent, at least one selected from the group consisting of water, ethanol, propylene glycol, triacetin, glycerin, methanol, 1-propanol, 2-propanol, acetone, and ethyl acetate can be used. However, from the viewpoint of extraction efficiency and consumer safety, water and / or ethanol are preferred.

[0028] The effects of the present invention can be more effectively enjoyed by using the citral deterioration inhibitor described above in foods containing citral. Here, citral is a type of monoterpene aldehyde found in the peels of citrus fruits such as lemons and grapefruits, as well as in the leaves of lemongrass, lemon myrtle, and other plants of the same genus. Its CAS number is 5392-40-5, and it is an oily liquid with a strong citrus scent.

[0029] Examples of foods containing citral include beverages such as carbonated drinks, soft drinks, fruit juices, dairy drinks, lactic acid bacteria drinks, energy drinks, soy milk, and tea drinks; alcoholic beverages such as chuhai, cocktail drinks, sparkling wine, fruit wine, and herbal liquor; desserts such as ice cream, ice milk, lacto ice, frozen desserts, yogurt, pudding, and jelly; confectionery such as caramel, candy, tablets, crackers, biscuits, cookies, pies, chocolate, snacks, and chewing gum; soups such as Japanese-style soup and Western-style soup; jams; flavorings such as ponzu and dressings; various instant beverages; and various instant foods. Among these, beverages, alcoholic beverages, and desserts are preferred.

[0030] The total content of catechins and epigallocatechins in the food containing citral is preferably 0.005 to 50 ppm, more preferably 0.005 to 35 ppm, even more preferably 0.01 to 35 ppm, and particularly preferably 0.01 to 2 ppm. If the total content is less than 0.005 ppm, the effect of suppressing the deterioration of citral may not be obtained, and if it is more than 50 ppm, the original flavor of the food may be impaired.

[0031] The weight ratio of (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) in the citral-containing food is preferably 15 to 1400, more preferably 15 to 1000, even more preferably 15 to 650, and particularly preferably 17 to 440. If the weight ratio is less than 15, the masking effect against the strong flavors characteristic of catechin and epigallocatechin may plateau, and if it is greater than 1400, the masking effect against the strong flavors characteristic of catechin and epigallocatechin may not be sufficiently exerted, and the original flavor of the food may be impaired.

[0032] The citral content in the food containing citral is preferably 1 to 100 ppm, more preferably 1 to 50 ppm, and even more preferably 1 to 10 ppm. If the citral content is less than 1 ppm, the flavor of citral may not be sufficiently developed, and if it is more than 100 ppm, the deterioration of citral may not be sufficiently suppressed without impairing the original flavor of the food.

[0033] Furthermore, from the viewpoint of enjoying the effects of the present invention more effectively, the citral / (catechin + epigallocatechin) (weight ratio) in the food containing citral is preferably 0.3 to 150, more preferably 1 to 55, even more preferably 1 to 35, and particularly preferably 1 to 25.

[0034] When adding catechin, epigallocatechin, p-mentha-1,5,8-triene, p-mentha-1,3,8-triene, and 2-ethylidene-6-methyl-3,5-heptadienal to the food containing citral, each component may be added individually or all components may be mixed before addition. However, it is preferable to use the citral degradation inhibitor because it allows for easy adjustment to the desired content range.

[0035] When the citral deterioration inhibitor is used in food, the citral deterioration inhibitor content in the food is preferably 50 to 2000 ppm, more preferably 60 to 2000 ppm, and even more preferably 70 to 2000 ppm. If the citral deterioration inhibitor content is less than 50 ppm, the effect of suppressing citral deterioration may not be sufficiently obtained, and if it is more than 2000 ppm, the effect may plateau or the original flavor of the food may be impaired.

[0036] One embodiment of the method for producing the citral degradation inhibitor in the present invention is illustrated below. Specifically, it is preferable to have a step of pulsed electric field treatment of lemon myrtle under conditions of specific energy 0.005 to 1110 kJ / kg, electric field strength 3 to 55 kV / cm, and pulse width 500 to 40000 ns, followed by an extraction treatment. After the extraction treatment, it is preferable to have a step of removing the extraction residue as needed.

[0037] More specifically, for example, a mixture can be obtained by mixing appropriately shredded lemon myrtle and a solvent such that the ratio of lemon myrtle (dry weight) to solvent (weight ratio) is preferably 0.05 to 0.2, and then the mixture can be subjected to pulsed electric field treatment before the extraction process is carried out.

[0038] The temperature during the pulsed electric field treatment is preferably 5 to 80°C, and more preferably 5 to 60°C. If the temperature is lower than 5°C, the extraction efficiency of the active ingredient may be poor, or it may be difficult to produce the citral degradation inhibitor. If the temperature is higher than 80°C, the flavor of the lemon myrtle and the extracted active ingredient may be altered, and the desired lemon myrtle-derived extract (active ingredient) may not be obtained. Here, the active ingredient contains at least catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene, and preferably further contains 2-ethylidene-6-methyl-3,5-heptadienate.

[0039] The specific energy during the pulsed electric field treatment is preferably 0.005 to 1110 kJ / kg, more preferably 0.08 to 1110 kJ / kg, even more preferably 6.3 to 1110 kJ / kg, and particularly preferably 45 to 1110 kJ / kg. If the specific energy is less than 0.005 kJ / kg, the active ingredient for inhibiting citral deterioration may not be obtained. If it is greater than 1110 kJ / kg, the production time may be too long, or the equipment costs may become enormous, making manufacturing difficult. The specific energy refers to the energy imparted to the lemon myrtle and is calculated by multiplying the conductivity of the lemon myrtle-solvent mixture by the square of the electric field strength, multiplying the pulse width, and multiplying the number of pulse shots.

[0040] The electric field strength during the pulsed electric field treatment is preferably 3 to 55 kV / cm, more preferably 10 to 53 kV / cm, and even more preferably 10 to 28 kV / cm. If the electric field strength is less than 3 kV / cm, the active ingredient in the citral degradation suppression effect may not be obtained, and if it is greater than 55 kV / cm, the equipment cost may become enormous. The electric field strength is a value calculated from the output voltage (kV) and the distance between the electrodes (cm). When a charge is placed between two flat conductor plates to which voltage is applied, an electrical force acts on that charge. The region in which this force acts on the charge is called an electric field, and the strength of that force is called the electric field strength.

[0041] The pulse width during the pulsed electric field processing is preferably 500 to 40000 ns, more preferably 500 to 2000 ns, even more preferably 500 to 1450 ns, and particularly preferably 580 to 1450 ns. If the pulse width falls outside the above range, the active ingredient in the citral degradation suppression effect may not be obtained. The pulse width refers to the duration of the pulse, and the waveform is not particularly limited; for example, it may be a square wave, triangular wave, sinusoidal wave, etc. This can be adjusted by changing the circuit configuration of the pulse power generator, and the waveform can be observed with an oscilloscope.

[0042] The extraction method is not particularly limited, but examples include pressurized extraction, heated and stirred extraction, reflux extraction, and the like.

[0043] The following are examples of extraction conditions when performing pressurized extraction in the extraction process described above. The pressurized conditions are preferably 0.01 to 50 MPa (gauge pressure), more preferably 0.05 to 5 MPa (gauge pressure), and even more preferably 0.1 to 0.5 MPa (gauge pressure). If the pressurized conditions are lower than 0.01 MPa (gauge pressure), the extraction efficiency may decrease, and if they are higher than 50 MPa (gauge pressure), the manufacturing equipment may become large-scale and the manufacturing cost may increase. Note that gauge pressure is a relative pressure with atmospheric pressure as zero.

[0044] The temperature for pressurized extraction is preferably 0 to 100°C, more preferably 20 to 80°C, and even more preferably 40 to 60°C. If the extraction temperature is lower than 0°C, the extraction efficiency may decrease, and if it is higher than 100°C, undesirable flavors such as burnt flavors and unpleasant aftertastes may be produced.

[0045] The time required for pressurized extraction is preferably 30 seconds to 600 minutes, more preferably 5 to 120 minutes, and even more preferably 30 to 60 minutes. If the extraction time is shorter than 30 seconds, the extraction efficiency may be poor, and if it is longer than 600 minutes, the extraction efficiency may plateau.

[0046] The method for removing the extraction residue is not particularly limited, but examples include filtration, centrifugation, sedimentation, and compression.

[0047] When preparing the citral degradation inhibitor of the present invention using an extract derived from lemon myrtle, the extract itself obtained by pulsed electric field treatment and extraction treatment of lemon myrtle, the extract itself obtained by removing the residue after pulsed electric field treatment and extraction treatment, or concentrated or diluted products obtained by concentrating these extracts can be used.

[0048] Furthermore, the citral degradation inhibitor may be in the form of a solid obtained by drying the extract. The shape of the solid is not particularly limited and may be in the form of a powder, granules, block, etc.

[0049] The citral degradation inhibitor may contain any components other than catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene. Such optional components are not particularly limited as long as they do not hinder the effects of the invention, and include solvents used for extracting lemon myrtle extracts; terpene hydrocarbons such as valencene and nootkatone; citrus-flavored components such as terpene alcohols including α,β-sinenol, α-terpineol, and borneol; and food components such as alcohols and sugars.

[0050] The method of using the citral deterioration inhibitor of the present invention in food is not particularly limited and can be done according to conventional methods. For example, it can be incorporated into food by adding and mixing it during or after the manufacturing process. [Examples]

[0051] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to these examples. In the examples, "parts" and "%" are based on weight.

[0052] Furthermore, the raw materials used in the examples and comparative examples are as follows. 1) Cargill Japan Co., Ltd. "Australian Lemon Myrtle" 2) "Specific 95-degree fermented alcohol" manufactured by Yamaichi Chemical Industry Co., Ltd., diluted with water to an alcohol concentration of 60%. 3) "Specific 95-degree fermented alcohol" manufactured by Yamaichi Chemical Industry Co., Ltd. 4) Propylene glycol food additive manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 5) "(+)-Catechin Standard" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 6) "(-)-Epigallocatechin Standard" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 7) Granulated sugar manufactured by Nisshin Sugar Co., Ltd. 8) Citric Acid (Anhydrous) manufactured by DSP Gokyo Food & Chemical Co., Ltd. 9) Purified sodium citrate manufactured by Fuso Chemical Industries, Ltd. 10) Citral (cis-,trans- mixture) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 11) "Lemon Concentrate Juice 400 GPL Turbid" manufactured by Nagano Sanyo Foods Co., Ltd. 12) "Ina Agar L" manufactured by Ina Food Industry Co., Ltd.

[0053] <Method for measuring each content> The content of catechins and epigallocatechins was analyzed based on the LC / MS / MS analytical method described above. In addition, the content of citral, p-methylacetophenone, p-cresol, 2-ethylidene-6-methyl-3,5-heptadienal, p-menta-1,5,8-triene, and p-menta-1,3,8-triene was measured based on the GC / MS analytical method described above.

[0054] <Evaluation of the effect of inhibiting citral degradation> Granulated sugar: 7.5 parts by weight, citric acid: 0.2 parts by weight, and sodium citrate: 0.04 parts by weight were dissolved in water to a total volume of 100 parts by weight, and then heat-sterilized at 80°C for 10 minutes to prepare an evaluation beverage. 99.85 parts by weight of this evaluation beverage and 0.15 parts by weight of citral degradation inhibitor were mixed, and citral was added to the evaluation beverage to a citral content of 10 ppm to prepare an evaluation beverage (test group). On the other hand, 10 ppm of citral was added to 100 parts by weight of the evaluation beverage to prepare an evaluation beverage (control group) without the citral degradation inhibitor. These evaluation beverages were stored in the dark at 55°C for 2 weeks, and the amount of p-methylacetophenone and p-cresol produced in each was measured by DHS-GC / MS analysis. The citral degradation rate (%) was calculated using the following formula and evaluated according to the following criteria.

[0055] Citral degradation rate (%) = {(amount of p-methylacetophenone in the test group) / (amount of p-methylacetophenone in the control group)} × 100 + {(amount of p-cresol in the test group) / (amount of p-cresol in the control group)} × 100 5 points: The citral degradation rate is between 0% and 40%, indicating a very high citral degradation suppression effect. 4 points: The citral degradation rate is between 40% and 60%, indicating a high citral degradation suppression effect. 3 points: The citral degradation rate is between 60% and 80%, indicating a slightly inferior citral degradation suppression effect, but it is still at a level that does not pose a problem in terms of product quality. Points 2: The citral degradation rate is between 80% and 100%, indicating a low effectiveness in suppressing citral degradation. Point 1: The citral degradation rate is between 100% and 200%, indicating a very low citral degradation inhibition effect.

[0056] <Evaluation of foods containing citral> After manufacturing each citral-containing food obtained in the examples and comparative examples, they were stored under predetermined conditions, and then evaluated by 10 skilled panelists. The average of their evaluation scores was used as the sensory evaluation. The evaluation criteria were as follows:

[0057] (The original flavor of the food) Comparison with citral-containing foods immediately after manufacturing without the addition of citral deterioration inhibitors (Reference Examples 1-5) 5 points: Equivalent to the reference example, and the original flavor of the citral-containing food is clearly discernible. 4 points: Slightly inferior to the reference example, but the original flavor of citral-containing foods can be felt. 3 points: It is inferior to the reference example, and the original flavor of the citral-containing food is slightly weaker, but it is still at an acceptable level in terms of product quality. Points 2: Worse than the example, the original flavor of the citral-containing food is not very noticeable. 1 point: It was significantly worse than the example, and the original flavor of the citral-containing food was completely absent.

[0058] (Lack of off-flavors) Comparison with citral-containing foods immediately after manufacturing without the addition of citral deterioration inhibitors (Reference Examples 1-5) 5 points: Equivalent to the example, with no off-flavors detected at all. 4 points: Slightly inferior to the reference example, but no off-flavors were detected. 3 points: It is inferior to the reference example, and a slight off-flavor is noticeable, but it is still at a level that does not affect the product quality. 2 points: Worse than the example, with noticeable off-flavors. 1 point: Significantly worse than the example, with clearly noticeable off-flavors.

[0059] (comprehensive evaluation) An overall evaluation was conducted based on the assessment results of the food's original flavor and the absence of off-flavors. The evaluation criteria were as follows: A: Products that meet the criteria of having both the original flavor of the food and the absence of off-flavors, with both scores being between 4.0 and 5.0 points. B: The food's original flavor and the absence of off-flavors are both rated between 3.5 and 5.0, and there is at least one item that is rated between 3.5 and 4.0. C: The food's original flavor and the absence of off-flavors are both rated between 3.0 and 5.0, and there is at least one item that is rated between 3.0 and 3.5. D: The food's original flavor and the absence of off-flavors are both rated between 2.0 and 5.0, and there is at least one item that is rated between 2.0 and 3.0. E: Products that have at least one item that scores below 2.0 in the evaluation of the food's original flavor and the absence of off-flavors.

[0060] (Example 1) Preparation of pulsed electric field treated extract According to the formulations shown in Table 1, 14.3 parts by weight of dried lemon myrtle (Cargill) and 85.7 parts by weight of a 60 wt% ethanol aqueous solution were placed in the sample processing tank of a high-voltage pulse processing system, and pulsed electric field treatment was performed under the conditions shown in Table 1 (specific energy: 101 kJ / kg, electric field strength: 25 kV / cm, pulse width: 600 ns). After pulsed electric field treatment, the sample and solvent in the sample processing tank were transferred to a glass container with a stirrer (Tai-atsu Glass Industry Co., Ltd.; TEM-U1000N), and extraction was performed under the extraction conditions shown in Table 1 (gauge pressure: 0.2 MPa, temperature: 40°C, extraction time: 30 min). After extraction, solid components were removed by filtration using filter paper (ADVANTEC No. 2) to obtain the pulsed electric field treated extract, which was used as a citral degradation inhibitor. The results of the component content measurement of the obtained pulsed electric field treated extract (citral degradation inhibitor) and the citral degradation inhibitory effect are shown in Table 1.

[0061] [Table 1]

[0062] (Example 2) Preparation of pulsed electric field treated extract According to Table 1, a pulsed electric field treated extract was obtained in the same manner as in Example 1, except that the solvent was changed from a 60 wt% ethanol aqueous solution to a 95 wt% ethanol aqueous solution, the specific energy from 101 kJ / kg to 0.009 kJ / kg, the electric field strength from 25 kV / cm to 4 kV / cm, and the pulse width from 600 ns to 1400 ns. This extract was then used as a citral degradation inhibitor. The results of the component content measurement and citral degradation inhibitory effect of the obtained pulsed electric field treated extract (citral degradation inhibitor) are shown in Table 1.

[0063] (Example 3) Preparation of pulsed electric field treated extract According to Table 1, a pulsed electric field treated extract was obtained in the same manner as in Example 1, except that the solvent was changed from a 60 wt% ethanol aqueous solution to a 50 wt% propylene glycol aqueous solution, and the specific energy was changed from 101 kJ / kg to 48 kJ / kg. This extract was then used as a citral degradation inhibitor. The results of the component content measurement and citral degradation inhibitory effect of the obtained pulsed electric field treated extract (citral degradation inhibitor) are shown in Table 1.

[0064] (Example 4) Preparation of pulsed electric field treated extract According to Table 1, a pulsed electric field treated extract was obtained in the same manner as in Example 1, except that the sample was changed from 14.3 parts by weight to 6.5 parts by weight for dried lemon myrtle, the solvent from 85.7 parts by weight to 93.5 parts by weight for 60 wt% ethanol aqueous solution, and the specific energy from 101 kJ / kg to 24 kJ / kg. This was used as a citral degradation inhibitor. The results of the component content measurement and citral degradation inhibitory effect of the obtained pulsed electric field treated extract (citral degradation inhibitor) are shown in Table 1.

[0065] (Example 5) Preparation of pulsed electric field treated extract According to Table 1, a pulsed electric field treated extract was obtained in the same manner as in Example 1, except that the specific energy was changed from 101 kJ / kg to 8 kJ / kg, the electric field strength from 25 kV / cm to 4 kV / cm, and the pulse width from 600 ns to 35000 ns. This extract was then used as a citral degradation inhibitor. The results of the component content measurement and citral degradation inhibitory effect of the obtained pulsed electric field treated extract (citral degradation inhibitor) are shown in Table 1.

[0066] (Comparative Example 1) Preparation of pulsed electric field treated extract According to Table 1, a pulsed electric field treated extract was obtained in the same manner as in Example 1, except that the sample was changed from 14.3 parts by weight to 6.5 parts by weight for dried lemon myrtle, the solvent from 85.7 parts by weight to 93.5 parts by weight for 60 wt% ethanol aqueous solution, the specific energy was changed from 101 kJ / kg to 0.028 kJ / kg, the electric field strength was changed from 25 kV / cm to 2 kV / cm, and the pulse width was changed from 600 ns to 1200 ns. The results of the component content measurement of the obtained pulsed electric field treated extract and the effect of suppressing citral degradation are shown in Table 1.

[0067] (Comparative Example 2) Preparation of pulsed electric field treated extract A pulsed electric field treated extract was obtained in the same manner as in Example 1, except that the amount of dried lemon myrtle as the sample was changed from 14.3 parts by weight to 6.5 parts by weight, the solvent was changed from 85.7 parts by weight to 93.5 parts by weight, the specific energy was changed from 101 kJ / kg to 0.003 kJ / kg, and the electric field strength was changed from 25 kV / cm to 4 kV / cm, according to Table 1. The results of the component content measurement of the obtained pulsed electric field treated extract and the effect of suppressing citral degradation are shown in Table 1.

[0068] By pulsed electric field treatment under conditions of specific energy of 0.005 to 1110 kJ / kg, electric field strength of 3 to 55 kV / cm, and pulse width of 500 to 40000 ns, pulsed electric field treated extracts (citral degradation inhibitors) were obtained in which the total content of catechin and epigallocatechin was 128 to 570 ppm, and the (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) was 15 to 1400 (Examples 1 to 5). As is clear from Table 1, all of these citral degradation inhibitors showed good evaluation of their citral degradation inhibitory effect.

[0069] On the other hand, by pulsed electric field treatment under low electric field strength conditions of 2 kV / cm, a pulsed electric field treated extract was obtained with a low total content of catechin and epigallocatechin of 110 ppm and a high (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) of 44,000 (Comparative Example 1). By pulsed electric field treatment under low specific energy conditions of 0.003 kJ / kg, a pulsed electric field treated extract was obtained with a low total content of catechin and epigallocatechin of 125 ppm and a high (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) of 62,500 (Comparative Example 2). As is clear from Table 1, all of these pulsed electric field treated extracts showed poor evaluation of their citral degradation inhibitory effect.

[0070] (Example 6) Preparation of a citral degradation inhibitor According to Table 2, a citral degradation inhibitor was prepared by mixing 99.9825 parts by weight of the pulsed electric field treated extract obtained in Example 4, 0.010 parts by weight of catechin, and 0.0075 parts by weight of epigallocatechin. The results of the component content measurement of the obtained citral degradation inhibitor and the citral degradation inhibitory effect are shown in Table 2.

[0071] [Table 2]

[0072] As is clear from Table 2, the citral degradation inhibitors (Examples 4 and 6) with a total content of catechin and epigallocatechin of 128 to 570 ppm, a (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) of 15 to 1400, and a (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) / 2-ethylidene-6-methyl-3,5-heptadienal (weight ratio) in the range of 2 to 9 showed good evaluation of their citral degradation inhibitory effect.

[0073] (Example 7) Preparation of a citral-containing beverage According to the formulation shown in Table 3, 7.5 parts by weight of granulated sugar, 0.2 parts by weight of citric acid, 0.04 parts by weight of trisodium citrate, 0.0005 parts by weight of citral, and 0.15 parts by weight of the citral deterioration inhibitor from Example 1 were dissolved in 92.1095 parts by weight of water, and then heat-sterilized at 80°C for 10 minutes to prepare a citral-containing beverage. The resulting citral-containing beverage was stored in the dark at 55°C for 14 days, and the original flavor and absence of off-flavors were evaluated. The results are shown in Table 3.

[0074] [Table 3]

[0075] (Comparative Example 3) Preparation of a citral-containing beverage A citral-containing beverage was prepared in the same manner as in Example 7, except that the citral deterioration inhibitor from Example 1 was not added and the total volume was adjusted with water, according to the formulation in Table 3. The original flavor of the food and the absence of off-flavors of the obtained citral-containing beverage were evaluated after being stored in the dark at 55°C for 14 days, and the results are shown in Table 3.

[0076] (Reference example 1) The citral-containing beverage obtained in Comparative Example 3 was subjected to a sensory evaluation immediately after production and before storage. The results are shown in Table 3 as Reference Example 1, and were compared with Example 7 and Comparative Example 3.

[0077] As is clear from Table 3, the citral-containing beverage containing a citral deterioration inhibitor (Example 7) retained its original flavor and showed no off-flavors even after being stored in the dark at 55°C for 14 days, receiving a good evaluation. On the other hand, the citral-containing beverage without a citral deterioration inhibitor (Comparative Example 3) lost its original flavor and exhibited off-flavors after storage, resulting in an overall evaluation of E.

[0078] (Example 8) Preparation of a citral-containing beverage A citral-containing beverage was prepared in the same manner as in Example 7, except that the citral deterioration inhibitor in Example 1 was replaced with the citral deterioration inhibitor in Example 2, the citral content was changed from 0.0005 parts by weight to 0.0010 parts by weight, and the total amount was adjusted with water, according to the formulation in Table 3. The original flavor of the food and the absence of off-flavors were evaluated after storing the obtained citral-containing beverage in the dark at 55°C for 14 days, and the results are shown in Table 3.

[0079] (Comparative Example 4) Preparation of a citral-containing beverage A citral-containing beverage was prepared in the same manner as in Example 8, except that the citral deterioration inhibitor from Example 2 was not added and the total volume was adjusted with water, according to the formulation in Table 3. The original flavor of the food and the absence of off-flavors were evaluated after storing the obtained citral-containing beverage in the dark at 55°C for 14 days, and the results are shown in Table 3.

[0080] (Reference example 2) The citral-containing beverage obtained in Comparative Example 4 was subjected to a sensory evaluation immediately after production and before storage. The results are shown in Table 3 as Reference Example 2, and were compared with Example 8 and Comparative Example 4.

[0081] As is clear from Table 3, the citral-containing beverage containing a citral deterioration inhibitor (Example 8) retained its original flavor and showed no off-flavors even after being stored in the dark at 55°C for 14 days, receiving a good evaluation. On the other hand, the citral-containing beverage without a citral deterioration inhibitor (Comparative Example 4) lost its original flavor and exhibited off-flavors after storage, resulting in an overall evaluation of E.

[0082] (Example 9) Preparation of a citral-containing beverage A citral-containing beverage was prepared in the same manner as in Example 7, except that the citral deterioration inhibitor in Example 1 was replaced with the citral deterioration inhibitor in Example 3, the citral content was changed from 0.0005 parts by weight to 0.0020 parts by weight, and the total volume was adjusted with water, according to the formulation in Table 3. The original flavor of the food and the absence of off-flavors were evaluated after storing the obtained citral-containing beverage in the dark at 55°C for 14 days, and the results are shown in Table 3.

[0083] (Comparative Example 5) Preparation of a citral-containing beverage A citral-containing beverage was prepared in the same manner as in Example 9, except that the citral degradation inhibitor in Example 3 was replaced with the pulsed electric field treated extract in Comparative Example 1, according to the formulation in Table 3. The original flavor of the food and the absence of off-flavors were evaluated after storing the obtained citral-containing beverage in the dark at 55°C for 14 days, and the results are shown in Table 3.

[0084] (Comparative Example 6) Preparation of a citral-containing beverage A citral-containing beverage was prepared in the same manner as in Example 9, except that the citral deterioration inhibitor from Example 3 was not added and the total volume was adjusted with water, according to the formulation in Table 3. The original flavor of the food and the absence of off-flavors were evaluated after storing the obtained citral-containing beverage in the dark at 55°C for 14 days, and the results are shown in Table 3.

[0085] (Reference example 3) The citral-containing beverage obtained in Comparative Example 6 was subjected to a sensory evaluation immediately after production and before storage. The results are shown in Table 3 as Reference Example 3, and were compared with Example 9 and Comparative Examples 5 and 6.

[0086] As is clear from Table 3, the citral-containing beverage (Example 9), which contained a citral degradation inhibitor (Example 3), had a total content of catechin and epigallocatechin of 0.005 to 50 ppm, a (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) of 15 to 1400, and a citral content in the range of 1 to 100 ppm, and was well-received, as it retained the original flavor of the food and did not develop any off-flavors even after being stored in the dark at 55°C for 14 days. On the other hand, Comparative Example 5, a citral-containing beverage containing the pulsed electric field-treated extract of Comparative Example 1, with a high ratio of catechin + epigallocatechin / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (by weight) of 44,000, suffered from a loss of the original flavor of the food after storage, and off-flavors were also noticeable, resulting in an overall evaluation of D. Furthermore, a citral-containing beverage without a citral deterioration inhibitor (Comparative Example 6) clearly suffered from a loss of the original flavor of the food after storage, and off-flavors were also very noticeable, resulting in an overall evaluation of E.

[0087] (Examples 10 and 11, Comparative Example 7) Preparation of citral-containing beverages A citral-containing beverage was prepared in the same manner as in Example 7, except that the amount of citral was changed from 0.0005 parts by weight to 0.0025 parts by weight according to the formulation in Table 4, and the citral degradation inhibitor of Example 1 was changed to the citral degradation inhibitor of Example 4 (Example 10), the citral degradation inhibitor of Example 6 (Example 11), or the pulsed electric field treated extract of Comparative Example 2 (Comparative Example 7), and the total volume was adjusted with water. The citral-containing beverage was then evaluated for its original flavor and absence of off-flavors after being stored in the dark at 55°C for 14 days, and the results are shown in Table 4.

[0088] [Table 4]

[0089] (Comparative Example 8) Preparation of a citral-containing beverage A citral-containing beverage was prepared in the same manner as in Example 10, except that the citral deterioration inhibitor from Example 4 was omitted and the total volume was adjusted with water, according to the formulation in Table 4. The original flavor of the food and the absence of off-flavors were evaluated after storing the obtained citral-containing beverage in the dark at 55°C for 14 days, and the results are shown in Table 3.

[0090] (Reference example 4) The citral-containing beverage obtained in Comparative Example 8 was subjected to sensory evaluation immediately after production and before storage. The results are shown in Table 4 as Reference Example 4, and were compared with Examples 10, 11, and Comparative Examples 7 and 8.

[0091] As is clear from Table 4, citral-containing beverages (Examples 10 and 11) containing citral degradation inhibitors (Examples 4 and 6), with a total content of catechin and epigallocatechin of 0.005 to 50 ppm, a (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) of 15 to 1400, and a citral content in the range of 1 to 100 ppm, retained their original flavor and showed no off-flavors even after being stored in the dark at 55°C for 14 days, receiving a good evaluation. On the other hand, Comparative Example 7, a citral-containing beverage containing the pulsed electric field-treated extract of Comparative Example 2, with a high ratio of catechin + epigallocatechin / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (by weight) of 62,500, suffered from a loss of the original flavor of the food after storage, and off-flavors were also noticeable, resulting in an overall evaluation of D. Furthermore, a citral-containing beverage without a citral deterioration inhibitor (Comparative Example 8) clearly suffered from a loss of the original flavor of the food after storage, and off-flavors were also very noticeable, resulting in an overall evaluation of E.

[0092] (Example 12) Preparation of citral-containing jelly According to the formulation in Table 5, 15.0 parts by weight of granulated sugar, 0.2 parts by weight of citric acid, 1.0 part by weight of 5x concentrated lemon juice, 2.5 parts by weight of powdered agar, and 81.149 parts by weight of water were mixed. After heat sterilization at 80°C for 10 minutes, the mixture was cooled to 50°C. Then, 0.15 parts by weight of the citral deterioration inhibitor from Example 1 and 0.001 parts by weight of citral were added, and the mixture was filled into a light-shielding container and cooled to 5°C to prepare citral-containing jelly. The results of evaluating the original flavor and absence of off-flavors of the obtained citral-containing jelly after storage at 55°C for 7 days under light shielding are shown in Table 5.

[0093] [Table 5]

[0094] (Comparative Example 9) Preparation of citral-containing jelly Citral-containing jelly was prepared in the same manner as in Example 12, except that the citral degradation inhibitor in Example 1 was replaced with the pulsed electric field treated extract in Comparative Example 2, according to the formulation in Table 5. The original flavor and absence of off-flavors of the obtained citral-containing jelly were evaluated after storage at 55°C under light shielding for 7 days, and the results are shown in Table 5.

[0095] (Comparative Example 10) Preparation of citral-containing jelly Citral-containing jelly was prepared in the same manner as in Example 12, except that the citral deterioration inhibitor from Example 1 was not added and the total volume was adjusted with water, according to the formulation in Table 5. The original flavor of the food and the absence of off-flavors after storing the obtained citral-containing jelly in the dark at 55°C for 7 days are evaluated and shown in Table 5.

[0096] (Reference example 5) The citral-containing jelly obtained in Comparative Example 10 was subjected to a sensory evaluation immediately after production and before storage. The results are shown in Table 5 as Reference Example 5, and were compared with Example 12 and Comparative Examples 9 and 10.

[0097] As is clear from Table 5, the citral-containing jelly (Example 12), which contained a citral degradation inhibitor (Example 1), had a total content of catechin and epigallocatechin of 0.005 to 50 ppm, a (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (weight ratio) of 15 to 1400, and a citral content in the range of 1 to 100 ppm, was well-received, as it retained its original flavor and did not exhibit any off-flavors even after being stored in the dark at 55°C for 7 days. On the other hand, the citral-containing jelly (Comparative Example 9), which contained the pulsed electric field treated extract of Comparative Example 2 and had a large ratio of 62,500 for catechin + epigallocatechin / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (by weight), suffered a loss of its original flavor after storage, and off-flavors were also noticeable, resulting in an overall evaluation of D. Furthermore, the citral-containing jelly (Comparative Example 10), which did not contain a citral deterioration inhibitor, clearly suffered a loss of its original flavor after storage, and off-flavors were also very noticeable, resulting in an overall evaluation of E.

Claims

1. A method for producing a citral degradation inhibitor, The citral degradation inhibitor contains catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene. The total content of catechin and epigallocatechin is 128 to 570 ppm, and the ratio of (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (by weight) is 15 to 1400. A method for producing a citral degradation inhibitor, comprising the step of treating lemon myrtle with a pulsed electric field under conditions of specific energy 0.005 to 1110 kJ / kg, electric field strength 3 to 55 kV / cm, and pulse width 500 to 40000 ns, followed by an extraction process.

2. It contains catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene. The total content of catechin and epigallocatechin is 128 to 570 ppm, and the ratio of (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (by weight) is 15 to 1400. Catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene are extracts derived from lemon myrtle. The aforementioned lemon myrtle-derived extract, A citral degradation inhibitor obtained by pulsed electric field treatment of lemon myrtle under conditions of specific energy 0.005 to 1110 kJ / kg, electric field strength 3 to 55 kV / cm, and pulse width 500 to 40000 ns, followed by extraction.

3. Furthermore, it contains 2-ethylidene-6-methyl-3,5-heptadienal, The citral degradation inhibitor according to claim 2, wherein the ratio of (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) / 2-ethylidene-6-methyl-3,5-heptadienal (by weight) is 2 to 9.

4. It contains catechin, epigallocatechin, p-mentha-1,5,8-triene, p-mentha-1,3,8-triene, and citral. The total content of catechin and epigallocatechin is 0.005 to 50 ppm, the ratio of (catechin + epigallocatechin) / (p-mentha-1,5,8-triene + p-mentha-1,3,8-triene) (by weight) is 15 to 1400, and the citral content is 1 to 100 ppm. Catechin, epigallocatechin, p-mentha-1,5,8-triene, and p-mentha-1,3,8-triene are extracts derived from lemon myrtle. The aforementioned lemon myrtle-derived extract, This food product is obtained by treating lemon myrtle with a pulsed electric field under conditions of specific energy 0.005 to 1110 kJ / kg, electric field strength 3 to 55 kV / cm, and pulse width 500 to 40000 ns, followed by extraction.

5. A food containing 50 to 2000 ppm of the citral deterioration inhibitor described in claim 2 or 3 and citral.

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