Miso with high antioxidant properties and reduced browning, and processed products made from it.

Abstract

There was a demand for miso that would suppress browning after packaging and have a low salt content. [Solution] By mixing fermented and matured miso with rice that has been softened by adding 1 to 2.4 times its weight in water to polished rice and aging it for 48 hours or more in an environment between 45°C and 80°C, a miso is produced in which the decrease rate of Y / Y0 in the colorimetric Y value evaluation is 0.0067 or less and the salt content is 7% or less when kept at 25°C for 40 days or more. Furthermore, by incorporating this miso, it becomes possible to manufacture processed foods in which browning is suppressed.

Description

Technical Field

[0001] The present invention relates to miso characterized by suppressing browning due to oxidation by blending aged rice and having a salt content of 7% or less, and processed foods blended with this miso.

Background Art

[0002] The product miso undergoes browning after packaging. As the browning progresses, the flavor of the miso deteriorates, and the degree of browning progress determines the expiration date of the miso. In the case of ordinary rice miso, the expiration date is 6 months after packaging under normal temperature storage.

[0003] This browning is said to be caused by the formation of browning substances through the Maillard reaction between amino acids and saccharides in the miso. However, since the browning of the miso in the product progresses from the part in contact with air, it is considered that the browning after packaging is oxidation by oxygen in the air.

[0004] Therefore, deoxidizers are used in some of the miso in cups with voids. However, since miso has a long period until it is used up after opening, browning after opening cannot be prevented. Also, deoxidizers cannot be used in pillow-type packaging.

[0005] In the case of pillow-type packaged miso, there is almost no void between the miso and the packaging material. However, from aging the miso to packaging, there are processes such as color adjustment and pump transportation, and this process causes a large amount of oxygen to be entrapped in the miso, and the browning of the entire packaged miso progresses.

[0006] Preventing or suppressing the browning of packaged miso leads to an extension of the expiration period and also greatly contributes to a decrease in the product return rate due to the progress of browning.

[0007] On the other hand, while miso has a salt content of 11 to 13%, its water content is approximately 50%, resulting in a water-tolerant salt concentration of 17 to 21%, which is higher than that of soy sauce. This suppresses the breakdown of proteins and starches in the raw materials. Furthermore, lower salt content is desirable from a health perspective. However, lower salt content increases the concentration of amino acids and monosaccharides such as xylose and glucose, which are breakdown products of the raw materials, and promotes the amino-carbonyl reaction, which is thought to be the main cause of browning. Therefore, lower salt content is detrimental to preventing browning.

[0008] As suppressing browning in miso products contributes significantly to corporate profits and environmental protection, various browning suppression technologies have been developed. For canned miso soup, which has a longer shelf life than regular miso products, technologies are known to reduce the content of organic acids that promote browning (Patent Document 1) and to use deaerated water, which can be utilized under negative pressure (Patent Document 2). In addition, devices have been devised to minimize air entrapment during the blending and packaging processes of fermented miso (Patent Document 3). Furthermore, there is a technology to suppress the production of xylose, a monosaccharide that is the main component of browning substances, in the aminocarbonyl reaction (Patent Document 4). While these technologies have some effect up to the point of packaging and filling in general packaged miso, their browning prevention effect afterward is low.

[0009] It is known that miso contains melanoidins, which are antioxidants and brown-colored components. There is a technology (Patent Documents 5 and 6) that suppresses browning after packaging by increasing the melanoidin content. However, since melanoidins themselves are brown substances, this technology is difficult to use for light-colored miso and has a low browning suppression effect.

[0010] Technologies utilizing antioxidants include adding highly antioxidant flavonoids (Patent Document 7), adding calcium salts (Patent Document 8), and adding glutathione, a reducing agent (Patent Document 9), all of which have been developed to prevent browning after packaging. These added substances are additives and therefore require labeling, and are not commonly used as miso additives.

[0011] On the other hand, technological development for low-salt miso has been active for some time, and in recent years, manufacturing technology for salt-free miso (Patent Document 10) has also been developed. However, because low-salt or salt-free miso increases enzyme activity, browning progresses rapidly. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Patent No. 4723043 [Patent Document 2] Japanese Patent Application Publication No. 06-007123 [Patent Document 3] Japanese Patent Application Publication No. 10-179074 [Patent Document 4] Japanese Patent Publication No. 2001-095581 [Patent Document 5] Japanese Patent Publication No. 2006-333776 [Patent Document 6] Japanese Patent Publication No. 2017-012168 [Patent Document 7] Japanese Patent Publication No. 2009-178098 [Patent Document 8] Japanese Patent Application Publication No. 07-075517 [Patent Document 9] Japanese Patent Publication No. 2000-236834 [Patent Document 10] Japanese Patent Publication No. 2014-103862 [Overview of the project] [Problems that the invention aims to solve]

[0013] Packaged miso products have a long production period, with natural brewing taking over a year and heated brewing taking over four months. However, the browning after packaging is the main factor, resulting in a short shelf life of six months. After the fermentation and aging process, miso is in a low-oxygen state due to the action of yeast and is difficult to oxidize. However, during the subsequent mixing process in the preparation step and the transportation and filling in the packaging step, a large amount of air is entrained, and it is difficult to package it in a state without voids. Therefore, browning due to oxidation after packaging has become a major problem. In addition, due to the health-consciousness of consumers, low-salting is progressing, but the browning further progresses with the low-salting of miso.

[0014] Therefore, there has been a demand from manufacturers, distributors, and consumers for miso with a low salt content and particularly low browning after opening of the expiration date.

[0015] Therefore, the development of miso with a low salt content and suppressed browning was made an issue.

Means for Solving the Problems

[0016] The present inventors added water to polished rice at a weight ratio of 1 to 2.4 times and aged it for 48 hours or more in an environment of 45°C or higher and 80°C or lower to soften the rice (hereinafter referred to as water-added and heat-treated rice), and by blending it into miso after fermentation and aging, newly found that the reduction rate of Y / Y0 in the evaluation by the measured color Y value when maintained at 25°C for 40 days or more is 0.0067 or less, and thus completed the present invention.

[0017] Furthermore, by newly finding that the browning due to the aminocarbonyl reaction promoted by low-salting is suppressed even when the salt content is 7% or less by mixing water-added and heat-treated rice, the present invention was completed.

[0018] In addition, the water-added and heated rice is washed with water, drained, treated at 45°C to 55°C for 16 hours, and then water is added so that the total water addition rate becomes 170% or more with respect to the rice before the treatment, and by performing a heating treatment at 55°C or higher, it was newly found that the browning of miso mixed with this water-added and heat-treated rice is suppressed, and the present invention was completed.

[0019] Furthermore, the inventors have newly found that by blending the heat-moisture treated rice with the fermented and aged miso, it is possible to produce excellent processed foods, thus completing the present invention.

[0020] The present invention provides the following (1), (2), (3), and (4). (1) A miso characterized in that by blending heat-moisture treated rice with miso after fermentation and aging, the reduction rate of Y / Y0 in the evaluation by colorimetric Y value when maintained at 25°C for 40 days or more is 0.0067 or less. (2) A miso characterized in that the salt content of the miso described above is 7% or less. (3) The heat-moisture treated rice is washed, drained, treated at 45°C to 55°C for 16 hours, then water is added so that the total water addition rate becomes 170% or more with respect to the rice before treatment, and a warming treatment is performed at 55°C or higher, thereby providing a miso characterized in that the browning change of the miso mixed with this heat-moisture treated rice is suppressed. (4) A processed food characterized by containing the miso described in (2) above.

Effects of the Invention

[0021] According to the present invention, it becomes possible to supply miso with suppressed browning change when maintained at 25°C for 40 days or more, miso having a browning suppression effect even with a salt content of 7% or less, and processed foods containing such miso.

Modes for Carrying Out the Invention

[0022] As described above, the inventors have newly found that by blending heat-moisture treated rice with miso after fermentation and aging, it becomes miso with suppressed browning change where the reduction rate of Y / Y0 in the evaluation by colorimetric Y value when maintained at 2�°C for 40 days or more is 0.0067 or less, thus completing the present invention. Furthermore, the inventors have newly found that miso containing heat-moisture treated rice has a browning suppression effect even with a salt content of 7% or less, thus completing the present invention. Furthermore, the inventors have newly found that by blending the above miso, it is possible to produce excellent processed foods, thus completing the present invention.

[0023] The miso of the present invention is characterized in that, by blending water-heat-treated rice with miso after fermentation and maturation, the decrease rate of Y / Y0 in the colorimetric Y value evaluation is 0.0067 or less when held at 25°C for 40 days or more.

[0024] The miso of the present invention is characterized by having a decrease rate of Y / Y0 of 0.0067 or less in the colorimetric Y value evaluation when stored at 25°C for 40 days or more, and a salt content of 7% or less.

[0025] The processed food of the present invention is characterized by containing the aforementioned miso. [Examples]

[0026] The present invention will be described in more detail below with reference to experimental examples and embodiments, but the present invention is not limited thereto. [Examples]

[0027] Changes in Y / Y0 in evaluation based on the amount of water-heat-treated rice and the colorimetric Y value

[0028] Red miso was mixed with water-treated and heat-treated rice to achieve a salt content of 5%, and then filled into a resealable packaging material. This was heated in a constant temperature bath maintained at 25°C for 40 days, and chromaticity measurements were performed after a certain period. A ZE6000 colorimeter manufactured by Nippon Denshoku Kogyo Co., Ltd. was used for chromaticity measurement, and the XYZ system, which is used for evaluating the chromaticity of miso, was adopted as the color index. The chromaticity of miso alone (red miso and rice koji miso) without water-treated and heat-treated rice was measured and compared. In comparing the color changes, the initial chromaticity before being placed in the constant temperature bath was defined as Y0 (%), and the chromaticity after heating was defined as Y (%). The slope value (defined as the decrease rate of Y / Y0) when approximating the plot of elapsed time (days) - Y / Y0 with a linear function was used as the index.

[0029] The color changes of miso made with 5% salt-containing water-heat-treated rice, red miso alone, and rice koji miso alone were measured, and the slope of the plot of elapsed time (days) - Y / Y0 was approximated by a linear function and calculated. The color change rates for each type of miso are shown in Table 1. In the XYZ system, the Y value is an indicator of the brightness of the miso color, with a larger value indicating a brighter color. In other words, a smaller Y / Y0 value indicates that the miso has browned. In all three types of miso—water-heat-treated rice-containing miso (5% salt), red miso alone, and rice koji miso alone—the Y / Y0 value tended to decrease with increasing heating time, but the decrease rate was smallest in the water-heat-treated rice-containing miso with 5% salt, indicating that salt browning was most suppressed.

[0030] [Table 1] [Examples]

[0031] Water-treated and heat-treated rice blend

[0032] Red miso was mixed with water-treated rice to achieve salt content of 3%, 5%, and 7%, and then filled into resealable packaging. This was heated in a constant temperature bath maintained at 25°C for 45 days, and color measurement was performed after a certain period. The indicators for color measurement and color change were the same as in Example 1.

[0033] Table 2 shows the slope values ​​of a linear function approximating the elapsed time -Y / Y0 plot for samples blended with varying amounts of water-heat-treated rice to achieve different salt concentrations. Note that the salt concentration was adjusted by the proportion of water-heat-treated rice used in the blend; a lower salt concentration means a higher proportion of water-heat-treated rice. The color change rates for water-heat-treated rice blended miso at each salt concentration are shown in Table 2. In all samples with 3%, 5%, and 7% salt concentrations, the Y / Y0 value tended to decrease with increasing heating time, but the decrease rate was smallest in the water-heat-treated rice blended miso with 3% salt concentration, indicating the most suppressed browning.

[0034] [Table 2] [Examples]

[0035] Processed agricultural products

[0036] As an example of a processed product using miso containing water-heat-treated rice, a miso sauce for boiled fish was prototyped. The various ingredients listed in Table 3 were mixed in a stainless steel beaker and heated to 90°C while stirring. Note that water-heat-treated rice-containing miso (5% salt content) means miso in which the amount of water-heat-treated rice has been adjusted to achieve a salt concentration of 5%. After reaching 90°C, it was held for 1 minute to sterilize, and then cooled to 25°C. Finally, it was filled into a sealable packaging material in the same manner as described in Examples 1 and 2. This was kept in a constant temperature bath set at 25°C for 14 days, and color measurement was performed after a certain period. The index for color measurement and color change was the same as in Example 1. In addition, a miso sauce for boiled fish containing red miso was also prepared and the color change was compared.

[0037] [Table 3]

[0038] Table 4 shows the values ​​of the slope when the elapsed time -Y / Y0 plot for each sample was approximated by a linear function. In both the miso sauce for boiled fish (A) and (B), the value of Y / Y0 tended to decrease as the heating time increased. However, in the case of miso sauce for boiled fish (A) which contains miso made from water-heat-treated rice, the rate of decrease in Y / Y0 was smaller and browning was suppressed. In addition, in this verification, after heating each sample in a constant temperature bath maintained at 25°C for 40 days, the total viable cell count, heat-resistant cell count, and coliform bacteria count were investigated using Petri film, but no colony formation was observed for any of the items.

[0039] [Table 4] [Industrial applicability]

[0040] This invention relates to miso characterized by suppressing browning, with a decrease rate of Y / Y0 in the colorimetric Y value evaluation of 0.0067 or less when stored at 25°C for 40 days or more, by blending water-heat-treated rice with fermented and matured miso, and to miso that suppresses browning even when the salt content of the water-heat-treated rice blended with miso is 7% or less, and to processed foods that incorporate these. The miso of this invention makes it possible to supply miso with suppressed browning at low salt content and processed foods that incorporate it.

Claims

1. Miso characterized by a decrease rate of Y / Y0 in the colorimetric Y value evaluation of 0.0067 or less when mixed with water-heat-treated rice and held at 25°C for 40 days or more.

2. Miso characterized in that the salt content of the miso according to claim 1 is 7% or less.

3. The miso according to claim 1, characterized in that it is made by processing rice at 45°C to 55°C for 16 hours, and then adding water and heating to soften the rice before blending it.

4. Processed food characterized by containing the miso described in claim 2.

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