Koji mold-ripened cheese and method for producing the same

Abstract

To provide a mature Aspergillus oryzae cheese that contains 3-hydroxy-3-methylglutaric acid (HMG).SOLUTION: The mature Aspergillus oryzae cheese contains 3-hydroxy-3-methylglutaric acid.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to koji-ripened cheese made using koji mold, which has excellent texture and a delicious flavor, and further contains 3-hydroxy-3-methylglutaric acid (HMG), which is involved in cholesterol biosynthesis, and a method for producing the same. [Background technology]

[0002] Cheese is a fermented food produced by the action of microorganisms. Natural cheese includes so-called aged cheese, which is made by aging curds formed by coagulating milk using lactic acid bacteria or mold. Mold-aged cheese, in particular, is gaining popularity among Japanese consumers due to its diverse flavors and textures. According to statistics from the Ministry of Agriculture, Forestry and Fisheries, Japan's cheese consumption has increased 1.2 times compared to 10 years ago, and natural cheese consumption is also on the rise. However, despite a significant increase in the number of domestic cheese factories in recent years, approximately 90% of natural cheese consumption is imported. In response to the growing momentum for developing domestic natural cheese, a strain of Aspergillus genus koji mold suitable for cheese aging was selected from among koji molds, and a new mold-aged cheese, "Koji-mold-matured cheese," was developed (see Patent Document 1). While the document describes the production conditions for koji-mold-matured cheese to obtain excellent flavor and texture, it does not mention the addition of specific components, other than glutamic acid, which contributes to umami.

[0003] 3-Hydroxy-3-methylglutaric acid (HMG) is known to be a substance involved in the cholesterol biosynthesis pathway, and a method has been developed for producing 3-hydroxy-3-methylglutaric acid (HMG) in a medium by fermentation using the sap-derived yeast Candida sorbosa 5B-2 strain (Patent Document 2). This document describes a method for producing HMG as a valuable substance by fermentation, but because the yeast strain used is not a food-derived or microbial species that has been eaten, it was not actually intended for the production of directly edible fermented foods. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-129536 [Patent Document 2] Japanese Patent Application Publication No. 54-86690 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a koji-ripened cheese containing 3-hydroxy-3-methylglutaric acid (HMG). [Means for solving the problem]

[0006] In an effort to solve the above-mentioned problems, the inventors of the present application discovered an A. oryzae strain capable of producing HMG in cheese while working to expand the range of strains suitable for cheese ripening. Aspergillus oryzae is a microorganism with a long history of use in food, and its genetic safety has been proven. Unlike C. sorbosa, described in JP 54-86690 A, it can be used to produce directly edible fermented foods. The use of Aspergillus oryzae for cheese ripening is described in JP 2021-129536 A, JP 2009-100678 A, and JP 2010-246499 A, but cheese containing 3-hydroxy-3-methylglutaric acid (HMG) is not described.

[0007] The present inventors have discovered a new method for producing koji-ripened cheese containing 3-hydroxy-3-methylglutaric acid (HMG), which had not previously existed, and have completed the present invention.

[0008] That is, the present invention is as follows. [1] Mold-ripened cheese containing 3-hydroxy-3-methylglutaric acid. [2] Mold-ripened cheese is a type of cheese that is ripened using koji mold.[1] [3] The koji-ripened cheese according to [2], characterized in that the content of 3-hydroxy-3-methylglutaric acid is 10 mg% or more per cheese solids. [4] The koji-ripened cheese of [2] or [3], characterized in that the content of 3-hydroxy-3-methylglutaric acid is 50 mg% or more per cheese solids. [5] The koji-ripened cheese according to any one of [2] to [4], characterized in that the content of free glutamic acid in the ripened cheese is 200 mg% or more per cheese solid content. [6] The koji-ripened cheese according to any one of [2] to [5], characterized in that the content of free butyric acid in the ripened cheese is 30 mg% or less per cheese solid content. [7] A koji-ripened cheese according to any one of [2] to [6], characterized in that it contains Aspergillus oryzae capable of producing 3-hydroxy-3-methylglutaric acid (HMG). [8] (i) A process of adding a lactic acid bacteria starter to raw milk for cheese production and coagulating it with a milk-clotting enzyme; (ii) washing the cheese curds by replacing a portion of the whey with water or adding water to the whey; and (iii) A method for producing koji-ripened cheese containing 3-hydroxy-3-methylglutaric acid, comprising the steps of molding cheese curds, salting, inoculating koji mold, and ripening the cheese, A production method characterized by using a koji mold of the genus Aspergillus capable of producing 3-hydroxy-3-methylglutaric acid (HMG). [9] The method for producing koji-ripened cheese according to [8], wherein the koji mold of the genus Aspergillus capable of producing 3-hydroxy-3-methylglutaric acid (HMG) is Aspergillus oryzae. [Effects of the Invention]

[0009] The cheese of the present invention contains 3-hydroxy-3-methylglutaric acid (HMG), a feature not found in conventional mold-ripened cheeses. The koji-ripened cheese of the present invention containing 3-hydroxy-3-methylglutaric acid (HMG) can be used as a health food, a food with functional claims, a food for specified health uses, a food with nutrient functions, or the like, for improving hyperlipidemia and hypercholesterolemia. [Brief explanation of the drawings]

[0010] [Figure 1] Figure 1 shows the results of identifying HMG in strain Q-aged cheese. Figure 1A shows the H NMR spectrum, and Figure 1B shows the H-C HSQC spectrum. In Figure 1A, (a) shows the spectrum of a strain Q-aged cheese extract, and (b) shows the spectrum of an HMG standard (Merck). In Figure 1B, (a) shows the spectrum of a strain Q-aged cheese extract, and (b) shows the spectrum of an HMG standard (Merck). The arrows indicate the NMR signals derived from HMG. [Figure 2] This figure shows the results of a comparison of the H NMR spectra of strain Q and commercially available aged cheese. Figure 2A shows the stacked spectra, and Figure 2B shows the overlaid spectra with the HMG signal region enlarged. In Figure 2A, STD indicates the spectrum of the HMG standard (Merck), 1 indicates the spectrum of the strain Q aged cheese extract, and 2-22 indicate the spectra of extracts from 21 commercially available aged cheese products. The horizontal axis indicates the NMR chemical shift (ppm). The arrows indicate the unique region of the HMG signal that does not overlap with the signals of other components, and the numbers on the right of the figure indicate the signal area of ​​the unique HMG signal region. In Figure 2B, (a) indicates the spectrum of the strain Q aged cheese extract, (b) indicates the spectrum of the HMG standard (Merck), and the other spectra are spectra of commercially available aged cheese. [Figure 3]This figure shows the results of a comparison of the 1H NMR spectra of cheeses aged with the Q strain and other koji mold strains. Figure 3A shows the stacked spectra, and Figure 3B shows the overlaid spectra with the HMG signal region enlarged. In Figure 3A, "STD" indicates the spectrum of the HMG standard (Merck), "1" indicates the spectrum of the Q strain aged cheese extract, and "2-10" indicate the spectra of cheese extracts aged with other koji mold strains. The horizontal axis indicates the NMR chemical shift (ppm). The arrow indicates the intrinsic HMG signal region, and the numbers on the right of the figure indicate the signal area of ​​the intrinsic HMG signal region. In Figure 3B, (a) indicates the spectrum of the Q strain aged cheese extract, (b) indicates the spectrum of the HMG standard (Merck), and the other spectra are spectra of cheeses aged with other koji mold strains. [Figure 4] 4A and 4B show the appearance of aged cheeses made from the KC43 strain and the Q strain, respectively. [Figure 5] This figure shows the results of detecting HMG from cheese cultures of A. oryzae strains. In Figure 5, STD indicates the spectrum of an HMG standard (Merck), 1 indicates the spectrum of cheese fermented with strain Q, and 2 to 11 indicate the spectra of cheese fermented with other strains. The horizontal axis indicates NMR chemical shifts (ppm). Arrows indicate the detected HMG. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below.

[0012] The present invention relates to a mold-ripened cheese that is ripened using mold. Preferably, the cheese of the present invention is produced using koji mold. By using a specific koji mold, it is possible to produce koji mold-ripened cheese that has a good umami flavor and a soft texture, and further contains 3-hydroxy-3-methylglutaric acid (HMG).

[0013] The method for producing koji-ripened cheese of the present invention involves preparing cheese curds with a lactose content of 2.0% by weight or less, preferably 1.8% by weight or less, inoculating koji mold onto the surface or interior, or both, of the cheese curds, and ripening the cheese. By keeping the lactose content of the cheese solids at 2.0% by weight or less, preferably 1.8% by weight or less, koji mold growth is improved, allowing the enzymes produced by the koji mold to efficiently penetrate the interior, resulting in good ripening and the formation of a delicious, flavorful, and soft texture.

[0014] Specifically, raw milk is sterilized to produce cheese milk, which is then inoculated with a lactic acid bacteria starter. The raw milk can be any type of raw milk used in cheese production, including raw milk typically used in cheese production, concentrated milk, skim milk mixed with products containing a high milk fat content, such as butter or cream. The raw milk can be sterilized by holding it at 55 to 70°C, preferably 60 to 65°C, for 10 minutes to 1 hour, or by high-temperature short-time sterilization. The milk is then cooled to produce cheese milk. When the lactic acid bacteria starter is added, calcium chloride may be added to a concentration of approximately 0.005 to 0.1% by weight. After inoculation with the lactic acid bacteria starter, lactic acid is produced, resulting in an acidic pH. When the pH reaches 6.0 to 6.5, preferably 6.4 to 6.5, rennet (a milk-clotting enzyme) is added, and the mixture is stirred and coagulated to produce cheese curds. The curds are then cut into cubes and stirred to prevent the curd particles from clumping together. The above-mentioned steps of sterilizing raw milk, adding starter lactic acid bacteria, coagulating with a milk-clotting enzyme, cutting the cheese curd, and salting are steps in a typical cheese production method, and may be carried out by changing the conditions as appropriate.

[0015] Next, after coagulation and cutting of the raw milk, a process (hereinafter referred to as curd washing) is performed in which a portion of the whey is replaced with water to reduce the lactose content in the solids to 2.0% by weight or less, preferably 1.8% by weight or less. Curd washing can produce cheese curds with reduced lactose concentrations. Curd washing is a process of replacing whey with water. The whey-to-water replacement ratio is 0.25 to 0.80 parts, preferably 0.50 to 0.75 parts, of whey per 1 part of raw milk, and an equal or greater amount of water is added to produce hydrated whey, which is then discharged. This process produces cheese curds with reduced lactose content. If the whey replacement ratio is less than 0.25 parts, the amount of lactose reduction is insufficient, and the penetration of enzymes produced by koji mold into the cheese interior is slow, making it difficult for maturation to progress to the interior of the cheese. If the whey-to-water replacement ratio is 0.25 parts or more, the maturation effect is more pronounced, allowing maturation to progress to the interior of the cheese. The lactose content is desirably 2.0% by weight or less, preferably 1.8% by weight or less, of the cheese solids.

[0016] After curd washing, the cheese curd is filled into a mold, molded, and soaked in a salt solution to obtain green cheese before salting and ripening. The green cheese obtained through this process has a lactose content of 2.0% by weight or less, preferably 1.8% by weight or less, and a milk fat content of 40% by weight or more. The amount of free glutamic acid per solid in the green cheese is 20 to 30 mg% (mg per 100 g). The amount of lactose is preferably measured by high-performance liquid chromatography.

[0017] The salted cheese curd, or green cheese, is then inoculated with koji mold.

[0018] The koji mold used in the present invention may be any Aspergillus koji mold used in foods, as long as it is capable of producing 3-hydroxy-3-methylglutaric acid (HMG). Examples of suitable koji molds include Aspergillus oryzae, Aspergillus sojae, and their white mutants, Aspergillus luchuensis, and Aspergillus luchuensis mut. kawachii, which are effective in imparting a flavor with little lipolysis odor and a strong umami taste. Mixtures of these strains may also be used. The Aspergillus koji mold capable of producing 3-hydroxy-3-methylglutaric acid (HMG) can be prepared by producing green cheese using the method described in Example 1 below, inoculating candidate Aspergillus koji molds, culturing them at 35°C for 5 days, and obtaining an extract from the culture using the method described in Example 1. 1 The presence of 3-hydroxy-3-methylglutaric acid (HMG) can be confirmed by measuring the H NMR spectrum. If the extract contains 3-hydroxy-3-methylglutaric acid (HMG), it can be determined that the candidate Aspergillus species used has the ability to produce 3-hydroxy-3-methylglutaric acid (HMG) and will accumulate 3-hydroxy-3-methylglutaric acid (HMG) in the cheese culture medium.

[0019] Aspergillus koji molds capable of producing 3-hydroxy-3-methylglutaric acid (HMG) can be easily selected by performing the above-mentioned tests on available strains of Aspergillus koji molds. Similar tests can also be applied to filamentous fungi other than koji molds, such as Penicillium species, to select filamentous fungi other than koji molds capable of producing HMG.

[0020] Furthermore, Aspergillus koji molds capable of producing multiple types of 3-hydroxy-3-methylglutaric acid (HMG) can be obtained from strain-holding institutions, etc. Specific examples of such strains include the following:

[0021] ·NBRC 4177: Aspergillus oryzae (Ahlburg) Cohn NBRC 4177 is available from the Biotechnology Center of the National Institute of Technology and Evaluation (NITE) (2-5-8 Kazusa Kamatari, Kisarazu, Chiba, Japan).

[0022] ·RIB 1172: Aspergillus oryzae var. brunneus Murakami RIB 1172 is available from the National Research Institute of Brewing (3-7-1 Kagamiyama, Higashihiroshima, Hiroshima, Japan). Additionally, the same strain as RIB 1172 is available from the Biotechnology Center of the National Institute of Technology and Evaluation (NITE) as NRBC 30102: Aspergillus oryzae (Ahlburg) Cohn var. brunneus Murakami.

[0023] ·No.6052 strain: Aspergillus oryzae Aspergillus oryzae strain No. 6052, which is capable of producing 3-hydroxy-3-methylglutaric acid (HMG), can be isolated from strain BF2, which is available from Higuchi Matsunosuke Shoten.

[0024] Q strain: Aspergillus oryzae Strain Q is a descendant of strain No. 6052 mentioned above and is available from Higuchi Matsunosuke Shoten.

[0025] Furthermore, strains equivalent to the above strains can be used. Here, "equivalent strains" refers to strains derived from the above strains, strains from which the above strains are derived, or descendant strains of such strains. Equivalent strains may also be stored in other strain-holding institutions.

[0026] The koji mold can be inoculated by applying it to the surface of the cheese curd, dispersing it inside the cheese curd, or a combination of both. Specifically, it is preferable to directly contact the cheese curd with koji mold powder, such as koji mold cells or a culture of koji mold such as rice koji, or to pre-disperse the koji mold powder in a liquid such as water and then immerse the cheese curd in the dispersion, or both. The aging conditions are preferably a temperature of 3 to 40°C, preferably 3 to 37°C, and a relative humidity of 80% or higher, to promote koji mold growth. If the temperature is too low, koji mold growth will take too long and maturation will not proceed. Temperatures higher than 40°C are undesirable from the standpoints of hygiene and appearance, as they may allow the growth of microorganisms other than koji mold and may cause deformation due to softening of the cheese curd. The aging method may be carried out in several stages to obtain the good flavor and texture of koji mold-aged cheese. For example, fermentation may be carried out for 2 to 10 days, preferably 2 to 5 days, and more preferably 3 days, at a temperature of 10 to 40°C, preferably 30 to 40°C, and more preferably 35°C, followed by fermentation for 2 to 15 days, preferably 2 to 10 days, and more preferably 7 days at a temperature of 10 to 30°C, preferably 10 to 20°C, and more preferably 15°C, and then fermentation for 5 to 100 days, preferably 10 to 40 days, and more preferably 20 days at a temperature of 3 to 10°C, preferably 3 to 8°C, and more preferably 5°C. The relative humidity is preferably maintained at 80% or higher to allow growth of koji mold.

[0027] The "surface" of the cheese curd refers to the layer where the koji mold grows, and the "inside" refers to the inner part of the layer where the koji mold grows.

[0028] The koji-matured cheese produced by the above method may be subjected to a sterilization treatment to make it suitable for storage and distribution. This is done by holding the aged cheese for 10 minutes or more so that the product temperature at the center is 55°C or higher, but is not limited to this.

[0029] The koji-ripened cheese obtained by the present invention has a free glutamic acid content of 200 mg% or more (mg per 100 g) based on the solids, preferably 400 mg% or more, and exhibits a strong umami flavor with a rich taste. This flavor is differentiated from conventional mold-ripened cheeses, and it is possible to provide a cheese unique to Japan.

[0030] Furthermore, the amount of butyric acid in the koji-ripened cheese obtained by the present invention is 30 mg% or less (mg per 100 g) based on the solids, preferably 25 mg% or less, and a strong irritating odor is suppressed.

[0031] The content of 3-hydroxy-3-methylglutaric acid (HMG) is 10 mg% or more per solid (mg per 100 g), preferably 20 mg% or more, more preferably 30 mg% or more, even more preferably 40 mg% or more, even more preferably 50 mg% or more, even more preferably 60 mg% or more, even more preferably 70 mg% or more, even more preferably 75 mg% or more, even more preferably 80 mg% or more, even more preferably 90 mg% or more, and even more preferably 100 mg% or more.

[0032] 3-Hydroxy-3-methylglutaric acid (HMG) is involved in the cholesterol biosynthesis pathway in the body. In the body, 3-hydroxy-3-methylglutaric acid (HMG-CoA) is formed from acetyl coenzyme A via acetoacetyl CoA, and HMG-CoA is converted to mevalonate, ultimately producing cholesterol. HMG inhibits HMG-CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis. In 1967, oral administration of HMG to rats fed a high-cholesterol diet was confirmed to reduce serum cholesterol levels. In addition, intraperitoneal administration of HMG to rabbits was shown to reduce serum cholesterol as well as phospholipids and triglycerides.

[0033] Therefore, the koji-ripened cheese containing 3-hydroxy-3-methylglutaric acid (HMG) of the present invention can be used as a health food, a functional food, a food for specified health uses, a food with nutrient function claims, or the like to improve hyperlipidemia and hypercholesterolemia. Here, a food for specified health uses refers to a food that is taken in the diet for a specific health purpose and is labeled to indicate that the intake of the food is expected to achieve the health purpose. These foods may be labeled to indicate that they are used to improve, for example, hyperlipidemia or hypercholesterolemia.

[0034] In the koji-ripened cheese of the present invention, 3-hydroxy-3-methylglutaric acid (HMG) can be ingested in a single serving, for example, preferably 0.1 mg to 30 mg, more preferably 2 mg to 20 mg, and even more preferably 3 mg to 10 mg. Examples of lower limits for the amount of 3-hydroxy-3-methylglutaric acid (HMG) ingested in a single serving include 0.2 mg, 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg, and 5 mg, and examples of upper limits include 30 mg, 20 mg, 10 mg, 6 mg, and 5 mg. A preferred range for the amount of 3-hydroxy-3-methylglutaric acid (HMG) ingested in a single serving can be represented by a combination of the upper and lower limits.

[0035] Furthermore, the koji-ripened cheese obtained by the present invention has a softened texture and a soft mouthfeel. Using a texture analyzer (TA.XTplusC manufactured by Eiko Seiki Co., Ltd.), a cylindrical probe with a diameter of 5 mm was compressed / penetrated to a strain of 70% at a rate of 1 mm / sec using a texture analyzer. The maximum stress value was measured as the hardness of the cheese tissue. The maximum stress value was 0.0030 kg / mm 2 Less than or equal to 0.0025 kg / mm 2 The following is the result.

[0036] Furthermore, the koji mold used is present in a viable state in the final cheese product, and therefore the cheese obtained by the method of the present invention is also characterized by containing koji mold. [Example]

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

[0038] [Example 1] HMG production in ripened cheese by Aspergillus oryzae Raw milk (3.3% fat, 3.2% protein) was sterilized at 65°C for 30 minutes and then cooled to 30°C to produce cheese milk. 40 kg of cheese milk was inoculated with a lactic acid bacteria starter (CHN-11, Christian Hansen). When the pH reached 6.5-6.4, rennet (Kaimax, Christian Hansen) was added. After coagulation with rennet, the cheese was cut and stirred for 30 minutes while maintaining the temperature at 30°C. 20 kg of whey was then drained, and 30 kg of warm water at 30°C was added for curd washing. After standing for 30 minutes, the curd was poured into a 60 mm diameter cylindrical mold, inverted after 30 minutes, and then inverted three times every hour. The curd was then left standing overnight at 30°C. The cheese was then immersed in a salt solution to produce green cheese.

[0039] The green cheese obtained in the previous section was inoculated with koji mold by immersing it at room temperature in a water dispersion of conidia of Aspergillus oryzae strain Q (manufactured by Higuchi Matsunosuke Shoten). During the ripening process, the koji mold was propagated in an ripening chamber with a relative humidity of 80% or higher, first at 35°C for 3 days, then at 15°C for 7 days (a total of 10 days), and then at 5°C for 20 days (a total of 30 days), to obtain a ripened cheese sample.

[0040] Mature cheese samples were sliced ​​and placed in a container. They were then dried for one week using a freeze dryer and then finely ground using a pestle and mortar. 1.5 mL of heavy water was added to 120 mg of this powder, and the resulting components were extracted by heating at 90°C for 5 minutes. After centrifugation, 630 μL of the supernatant was mixed with 70 μL of 1 M deuterium oxide potassium phosphate buffer (pH 7.0, containing 10 mM maleic acid and 10 mM DSS-d6 as internal standards), and the resulting mixture was centrifuged. The resulting supernatant was used for the analysis of water-soluble components.

[0041] The component composition was analyzed by nuclear magnetic resonance (NMR) and the NMR spectrum was measured using a 500 MHz NMR device (manufactured by Bruker). 1 H NMR spectrum and 1 H- 13 C heteronuclear single quantum coherence (HSQC) spectra were measured. The NMR spectrum of a standard sample of 3-hydroxy-3-methylglutaric acid (HMG, also known as meglutol, CAS Registry Number 503-49-1) was measured under the same measurement conditions for qualitative analysis. The NMR spectrum was also analyzed using the NMR Suite (Chenomx) software for identification and quantitative analysis.

[0042] As a result of the spectrum analysis, as shown in Figure 1, 1 The HMG signal was confirmed in both H and HSQC spectra, indicating the presence of HMG in cheese aged from strain Q. Quantitative analysis indicated that, assuming a moisture content of 40%, 100 g of cheese aged from strain Q contained approximately 89.9 mg of HMG.

[0043] [Example 2] Comparison of HMG content with commercially available aged cheese Water-soluble components were extracted from cheese aged with Aspergillus oryzae strain Q using the same method as in Example 1, and the NMR spectrum was compared with that of extracts from 21 commercially available aged cheese products (Camembert, Brie, Gorgonzola, etc.). As a result, as shown in Figure 2, no HMG signal was detected in the commercially available aged cheese products, indicating that HMG is produced in cheese by aging using koji mold.

[0044] [Example 3] Koji strain capable of producing ripened cheese containing HMG Cheese samples were obtained by ripening using A. oryzae strain Q and different Aspergillus koji mold strains (strains 2041, B, C, D, K, N, M, O, P, R, and S) in the same manner as in Example 1. NMR spectra were measured and compared using extracts from each cheese. As a result, as shown in Figure 3, it was found that ripened cheese containing HMG can be obtained by ripening using a specific koji mold, such as A. oryzae strain Q, that is capable of producing HMG in cheese.

[0045] Example 4: Evaluation of ripened cheese containing HMG In the same manner as in Example 1, A. oryzae Q strain and A. oryzae KC43 strain (manufactured by Higuchi Matsunosuke Shoten), which is the ripening koji mold used in JP 2021-129536 A related to the production method of koji mold-ripened cheese, were used. Cheese samples were aged for a total of 16 days at 35 ° C. for 3 days, then at 15 ° C. for 7 days, then at 5 ° C. for 6 days, and for a total of 30 days at 35 ° C. for 3 days, then at 15 ° C. for 7 days, then at 5 ° C. for 20 days. In addition, for comparison, a sample aged for 16 days (13 days at 13 ° C. and 3 days at 5 ° C.) using an existing mold starter product for Camembert cheese ripening (Chr. Hansen Swing PC, Penicillium candidum) was also obtained.

[0046] Regarding taste, four evaluators conducted a sensory evaluation of the samples that had been aged for a total of 17 days.

[0047] The taste was evaluated in terms of umami, flavor, and softness (hardness) according to the criteria in Table 1.

[0048] [Table 1]

[0049] The contents of HMG, glutamic acid, and butyric acid were measured by NMR in the samples aged for a total of 16 days and 30 days, as in Example 1. The softening of the cheese tissue during aging was analyzed using a texture analyzer (TA.XTplusC, manufactured by Eiko Seiki Co., Ltd.). The maximum stress value when a cylindrical probe with a diameter of 5 mm was compressed / penetrated to 70% strain at a speed of 1 mm / sec was used to measure the firmness of the cheese tissue. The pH change of the cheese tissue was measured using a pH meter by dispersing 4 g of the sample in 20 mL of ion-exchanged water.

[0050] After the cheese ripening process, it was confirmed that the cheese made with A. oryzae strain Q containing HMG had mold growth throughout and had an appearance quality comparable to that of cheese made with the prior art strain KC43 (Figure 4).

[0051] The results of the analysis of physicochemical and physical properties are shown in Table 2. The presence of HMG was observed only in cheese aged with strain Q. The content of glutamic acid, a flavor component, was significantly higher in the Q strain koji-ripened cheese than in the P. candidum Camembert cheese, and even exceeded that of the KC43 strain koji-ripened cheese. Furthermore, the content increased significantly with increasing aging time. On the other hand, butyric acid, which has a strong, pungent odor reminiscent of aged cheese, was highest in P. candidum, but significantly lower in KC43 and Q strains, reaching approximately one-third or less of that in the same aging period. Regarding tissue hardness, P. candidum had the lowest, indicating a softer texture. In comparison, strains Q and KC43 showed higher hardness values, but strain Q had approximately two-thirds the hardness of KC43 after 16 days and one-third the hardness after 30 days, resulting in a relatively softer cheese texture. The pH of the cheese tissue from strain Q was higher than that of strain KC43, which is presumably responsible for the softening of the tissue. Overall, the cheese ripened with strain Q containing HMG had chemical characteristics similar to those of existing koji-ripened cheese, with a high glutamic acid and low butyric acid content, and was evaluated as being slightly better at softening the cheese tissue.

[0052] The results of the taste evaluation are shown in Table 3. In terms of umami, cheese made with strain Q was rated comparable to cheese made with strain KC43. This was rated higher than Camembert cheese made with P. candidum, indicating that cheese made with strain Q also exhibits the strong umami characteristic of koji-ripened cheese. Both cheeses were rated highly for overall flavor. Regarding texture softness, P. candidum was the most tender, resulting in a very soft texture, while KC43 was slightly lower, and existing koji-ripened cheeses were rated as being somewhat hard. In contrast, cheese made with strain Q showed improved texture softness. Overall, it was confirmed that cheese made with strain Q containing HMG is characterized by a soft texture in addition to the strong umami characteristic of koji-ripened cheese, resulting in a product with a pleasant sensory flavor.

[0053] [Table 2]

[0054] [Table 3]

[0055] [Example 5] A. oryzae strain (distributed strain) that accumulates HMG in cheese Green cheese produced in the same manner as in Example 1 was cut into approximately 1 cm cubes, and 10 strains of A. oryzae (strains provided by the National Research Institute of Brewing and the Biotechnology Center of the National Institute of Technology and Evaluation) were inoculated and cultured at 35°C for 5 days together with the control A. oryzae strain Q. Extracts obtained from each culture were used to 1 As a result of measuring and comparing H NMR spectra, as shown in Figure 5, it was confirmed that RIB 1172 and NBRC 4177 (arrows in the figure, sample numbers 7 and 10) accumulated HMG in the cheese culture medium. [Industrial Applicability]

[0056] This invention is expected to expand the lineup of koji mold strains that can be used to produce koji-ripened cheese and contribute to the promotion of koji-ripened cheese.

Claims

1. A koji-ripened cheese containing 10 mg or more of 3-hydroxy-3-methylglutaric acid (HMG) per cheese solids, characterized by containing Aspergillus oryzae capable of producing 3-hydroxy-3-methylglutaric acid (HMG).

2. (i) adding a lactic acid bacteria starter to raw milk for cheese production and coagulating it with a milk-clotting enzyme; (ii) washing the cheese curds by replacing a portion of the whey with water or adding water to the whey; and (iii) A method for producing koji-ripened cheese containing 3-hydroxy-3-methylglutaric acid, comprising the steps of molding cheese curds, salting, inoculating koji mold, and ripening the cheese, A production method characterized by using Aspergillus oryzae capable of producing 3-hydroxy-3-methylglutaric acid (HMG) as the koji mold.

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