JP7165845B2 - Storage shelf life improving agent for cooked rice and method for improving shelf life of cooked rice - Google Patents

Description

The present invention provides a high-concentration sodium acetate-containing brewed vinegar for the purpose of improving the shelf life of food used to obtain an excellent food without impairing the taste of the food, and a food, particularly a food using the high-concentration sodium acetate-containing brewed vinegar. The present invention relates to a method for improving the shelf life of cooked rice that can be distributed at room temperature, and a preparation for the purpose of improving the shelf life.

When producing cooked rice, various organic acids are used for the purpose of improving the shelf life of cooked rice. Among them, fermented vinegar has long been used for the purpose of extending the shelf life of food.

However, when the amount of brewed vinegar added to food is increased in order to improve the shelf life, the flavor of the food may be spoiled by producing sour taste or sour smell.

At present, not only brewed vinegar but also organic acids such as vinegar, acetic acid, succinic acid, fumaric acid, tartaric acid, citric acid and gluconic acid have been proposed.

Japanese Patent Application Laid-Open No. 2015-123003 discloses vinegar-containing cooked rice, which contains cold water-soluble starch decomposition products at a rate of 0.05 to 1 part by mass per 1 part by mass of the acid contained in the vinegar-containing cooked rice. Vinegar-containing boiled rice characterized by this has been proposed (Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-126697 describes a granular seasoning for cooked rice containing acetic acid, sugars, succinic acid, fumaric acid, tartaric acid, citric acid, and a high-intensity sweetener, a method for producing the same, and a cooked rice seasoning food. has been proposed (Patent Document 2).

Japanese Patent Application Laid-Open No. 2016-106625 describes cooked rice coated with an oil-in-water emulsion containing 5% or more and 30% or less edible oil and fat, vinegar, and octenyl succinated starch, and having a pH of 2 or more and 4.5 or less. proposed (Patent Document 3).

Japanese Patent Application Laid-Open No. 2001-8646 proposes a method for producing a cooked rice food by adding a gluconic acid solution as boiling water to a container (Patent Document 4).

Japanese Unexamined Patent Application Publication No. 2015-123003 JP 2015-126697 A JP 2016-106625 A JP-A-2001-8646

In recent years, consumers in Japan, as well as in Europe and the United States, have called for the use of natural materials to avoid chemically synthesized products in the production of food products. be The present inventors partially neutralized the brewed vinegar to generate sodium acetate, and thought of using the sodium acetate-containing brewed vinegar, which has reduced sourness and sour smell, to improve the shelf life of foods, especially cooked rice.

A high-concentration sodium acetate-containing brewed vinegar can be obtained by neutralizing a high-acidity brewed vinegar with sodium carbonate or sodium hydrogen carbonate in an equimolar amount to the acetic acid contained therein. The pH at this time is 7-8. Unfortunately, this high-concentration sodium acetate-containing brewed vinegar has a harsh taste, which is a drawback inherent to sodium acetate, and the taste is not preferable when added to foods.

Therefore, the present invention provides a high-concentration sodium acetate-containing brewed vinegar in which the harsh taste of sodium acetate is suppressed, and food products using the high-concentration sodium acetate-containing brewed vinegar, especially cooked rice that can be distributed at room temperature. An object of the present invention is to provide an agent and a method for improving the shelf life of cooked rice.

In order to solve the above problems, various investigations were conducted with the aim of reducing the harsh taste derived from sodium acetate, and unexpectedly, it was found that a small amount of sourness of acetic acid could reduce the harsh taste. That is, the inventors found that the above problems can be solved by neutralizing (partially neutralizing) so as to leave a small amount of acetic acid when neutralizing brewed vinegar (Japanese Patent Application No. 2018-237227).

The present invention has been made based on such findings, and is a brewed vinegar containing high concentration sodium acetate, which is obtained by neutralizing the acetic acid contained in the high acidity brewed vinegar with an inorganic sodium salt, and has a ratio of acetic acid / sodium acetate is in the range of 0.15 to 0.21 in mass ratio, and provides a brewed vinegar containing high concentration sodium acetate.

The present invention also provides a shelf-life improving agent for cooked rice, which contains the above-mentioned high-concentration sodium acetate-containing brewed vinegar.

Furthermore, the present invention provides a method for improving the shelf life of cooked rice, which comprises adding the above-mentioned brewed vinegar containing high-concentration sodium acetate to cooked rice.

According to the present invention, the harsh taste of sodium acetate generated by neutralization from brewed vinegar (seasoning vinegar), a highly safe seasoning that has been used for many years, is suppressed by leaving a small amount of acetic acid. To provide a shelf life improving agent for boiled rice, which is safe, excellent in shelf life improving effect and does not impair the flavor of cooked rice, and a method for improving the shelf life of boiled rice, since brewed vinegar containing high-concentration sodium acetate can be produced. can do.

A high-concentration sodium acetate-containing brewed vinegar according to an embodiment of the present invention will be described. The high-concentration sodium acetate-containing brewed vinegar of the present embodiment is a high-concentration sodium acetate-containing brewed vinegar obtained by neutralizing the acetic acid contained in the high-acidity brewed vinegar with an inorganic sodium salt, and the ratio of acetic acid / sodium acetate is in the range of 0.15 to 0.21 in mass ratio .

In the present embodiment, "high acidity brewed vinegar" refers to brewed vinegar having an acidity of 10% by weight or more, preferably 15% by weight or more, and may be 20% by weight or more. However, from the viewpoint of the solubility of the neutralizing agent, the upper limit is about 30% by weight .

In the present embodiment, the “high concentration” in brewed vinegar containing high concentration sodium acetate means around 26%, which is the solubility of sodium acetate in water at 0 ° C., in the case of liquid, and 60% in the case of powder. means greater than or equal to

In this embodiment, the inorganic sodium salt is preferably sodium hydrogen carbonate or sodium carbonate.

In this embodiment, the high-concentration sodium acetate-containing brewed vinegar is preferably liquid. If it is liquid, it can be used in the same way as general brewed vinegar.

In this embodiment, the high-concentration sodium acetate-containing brewed vinegar can also be powdered. If it is powdered, the concentration can be increased to 60% or more.

The high-concentration sodium acetate-containing brewed vinegar according to the present embodiment can be produced by partially neutralizing high-acidity brewed vinegar with an acetic acid concentration in the range of 10 to 20% with an inorganic sodium salt.

The conditions for partial neutralization are such that the ratio of acetic acid/sodium acetate is in the range of 0.15 to 0.21 by mass, but depending on the purpose of use, the acidity of the brewed vinegar and the degree of partial neutralization are appropriately adjusted. Select is preferred.

Next, the shelf life improving agent for boiled rice of the present invention will be described. The shelf life improving agent for cooked rice according to the present embodiment is characterized by containing the above-described high-concentration sodium acetate-containing brewed vinegar.

In the present embodiment, the range of rice to be covered is rice cooked through a cooking process such as adding water and seasonings to uncooked rice such as non-glutinous rice and glutinous rice, and steaming, simmering, and baking (however, during cooking) (Excludes porridge made by adding 3.5 times more water to the weight of uncooked rice to soften the rice). Specific examples include white rice, sekihan, steamed rice, mixed rice, mixed rice, and paella. Also, cooked rice may be in any form of normal temperature, chilled or frozen.

The form of the shelf life improving agent for boiled rice of this embodiment is not particularly limited. For example, it may be in the form of powder, granules, granules, tablets, liquid, or paste. Powder, granules or granules are preferred because storage and transportation costs can be greatly reduced.

In the present embodiment, the amount of the shelf life improver for cooked rice is preferably 0.1 to 3% by weight, more preferably 0.5 to 2.4% by weight, based on the weight of uncooked rice. It is preferably 0.9 to 1.8% by weight, and more preferably 0.9 to 1.8% by weight.

The shelf life improving agent for cooked rice of this embodiment can contain a natural antibacterial substance and a food additive having a shelf life improving effect. Natural antibacterial substances and food additives that improve shelf life include chili pepper extracts, pectin decomposition products, hop extracts, protamine, polylysine, nisin, egg white lysozyme, licorice extract, and other naturally derived additives; betaine , glycine, amino acid additives such as alanine; lactic acid, citric acid, malic acid, fumaric acid, adipic acid, succinic acid, gluconic acid and other organic acids and inorganic salts thereof; calcium acetate, potassium acetate, lower fatty acid esters, sugar esters, vitamin B1 lauryl sulfate; In both cases, it is preferable to use food additive standard products.

Next, the method for improving the shelf life of cooked rice according to the present invention will be described. The method for improving shelf life of cooked rice according to the present embodiment is characterized by adding the above-described brewed vinegar containing high-concentration sodium acetate to cooked rice as a shelf life improving agent for cooked rice.

The timing of addition is not particularly limited, and the required amount of the high-concentration sodium acetate-containing brewed vinegar may be added to the cooked rice either before, during, or after cooking the cooked rice.

When the acetic acid/sodium acetate ratio (mass ratio) (hereinafter referred to as the A/B ratio) of 0.15 is applied to improve the shelf life of boiled rice, the slightly sour taste felt in porridge is no longer felt in boiled rice. The difference between porridge and boiled rice, that is, porridge and cooked rice, is presumed to be due to the fact that cooked rice has less moisture on the surface and the moisture is tightly trapped inside the grains of rice. For porridge, 0.14 is the allowable limit for sourness, but for cooked rice, even a large A/B ratio of 0.15 or more suppresses sourness and harshness, and accordingly the shelf life is improved. improves. That is, the higher the A/B ratio, the higher the shelf life improvement effect can be expected.

1. Effect of acetic acid on flavor of sodium acetate-containing brewed vinegar (part 1)
(1) Preparation of 20 wt % sodium acetate-containing brewed vinegar Contents of acid neutralization, that is, sodium acetate produced by neutralization (hereinafter sodium is abbreviated as "Na") tastes, and a small amount of acetic acid is added to the brewed vinegar containing Na acetate. A detailed study was conducted on the effects of vinegar on flavor. Three levels of high acidity brewed vinegar with an acidity of 20, 15 and 10% by weight were used. Specifically, the product with an acidity of 20% by weight is brewed vinegar Super Vinegar 20 (trade name, acidity 20% by weight ) manufactured by Uchibori Jozo Co., Ltd., and the product with an acidity of 15% is brewed vinegar HDV (trade name, acidity 15% by weight ), and the 10% acidity product was brewed vinegar DV (trade name, acidity 10% by weight ) manufactured by Kewpie Jozo Co., Ltd. When 20% by weight brewed vinegar was used so as to increase the solubility of Na bicarbonate, it was heated to 40° C. and used in the preparation of Reference Examples 1-3.

Table 1 shows Reference Examples 1 to 5 prepared as shelf life improvers for foods by partially neutralizing 20% by weight high acidity brewed vinegar. How to read Table 1 will be explained. In the case of Reference Example 3, the acetic acid concentration of 17% by weight means 17% by weight of 20% by weight brewed vinegar, that is, neutralization is carried out so that 3.4 g of acetic acid remains in 100 g of brewed vinegar. That is, 20 - 3.4 = 16.6 g of acetic acid will be used for neutralization. 16.6 g of acetic acid is 16.6/60=0.277 mol, and 0.277 mol (23.3 g) of Na bicarbonate is used to neutralize the acetic acid. Neutralization therefore yields 0.277 mol of Na acetate (22.7 g). The acidity content in the brewed vinegar is almost the same as the acidity, so the calculation in the reference example was performed using the concentration display.

The ratio of 3.4 g of acetic acid and 22.7 g of Na acetate was found to be 3.4/22.7=0.15. In Reference Examples 1 to 5, neutralization was carried out so that 0.4 to 4.8 g of acetic acid remained per 100 g of 20% by weight brewed vinegar. The range of Na acetate produced was 27-21% by weight . That is, the A/B ratios of Reference Examples 1 to 5 were 0.02, 0.12, 0.15, 0.21 and 0.24, respectively.

(2) Sensory test Table 2 shows the sensory test of the preparations of Reference Examples 1 to 5 after adding them to cooked rice (white rice). The method for preparing white rice is as follows. That is, to 100 g of rinse-free rice, 140 g of tap water, and 1 g of rice oil for cooking rice, 0.9% of the shelf life improvers for cooked rice of Reference Examples 1 to 5 were each added in terms of uncooked rice (0.38% of the total amount). ) was added and dissolved, and after soaking for 30 minutes, rice was cooked at 130° C. for 30 minutes in a Hoshizaki Electric steam convection oven. A preliminary test showed that 0.9% addition was appropriate, so 0.9% addition was adopted. In the sensory test, the sourness and harshness of acetic acid and sodium acetate were evaluated, and the scores were determined according to the scoring system (0 points; not felt, 1 point; felt with care, 2 points; slightly felt, 3 points; distinctly felt). Each reference example was evaluated. A sensory test was conducted on 10 panelists, and the average values of the scoring results were converted to -, ±, and + and shown in Table 2. In addition, if the average score of the 10 panelists for sourness and harshness is both less than 2.0 points, the overall evaluation is "acceptable", either the average value of the sourness or harshness. Or, when both were 2.0 points or more, "fail" was indicated as a rejected product.

As a comparison target for white rice, the same sensory test was performed by adding the shelf life improving agent for boiled rice to white porridge. The method for preparing white porridge is as follows. That is, prepare a small pot in which 200 g of water is added to 140 g of white rice, add 1.3 g each of the shelf life improving agent of Reference Examples 1 to 5 (0.38% of the total amount) to this pot, and heat for 15 minutes. and made porridge.

For white rice, the prepared products of Reference Example 2 (A/B ratio 0.12), Reference Example 3 (A/B ratio 0.15), and Reference Example 4 (A/B ratio 0.21) have a sour, eggy taste. The taste was also favorable (acceptable). That is, the acetic acid concentration after neutralization was in the range of 2.8-4.4%, and the Na acetate concentration was in the range of 24-21%. The present inventors focused on the ratio of the residual acetic acid after neutralization and the sodium acetate produced by neutralization, and found that the ratio of acetic acid/Na acetate was in the range of 0.12 to 0.21 for the preparations for which the overall evaluation was acceptable. was in Note that Reference Example 1 (A/B ratio of 0.02) had an acrid taste, and Reference Example 5 (A/B ratio of 0.24) had a strong sour taste, which were not preferable.

On the other hand, with respect to white rice porridge, the acrid taste was not acceptable in Reference Example 1, and the sour and acrid tastes were acceptable in Reference Example 2. In Reference Examples 3 to 5, it was not possible because it gave a sour taste.

(3) Storage test of cooked rice Reference Example 1 (Comparative Example 1), Reference Example 2 (Comparative Example 2), Reference Example 3 (Example 1), Reference Example 4 (Example 2), and Reference Example 5 in Table 1 The shelf life improving agent for food of (Comparative Example 3) was subjected to a storage test of cooked rice. 100 g of rinse-free rice, 140 g of tap water, and 1 g of rice oil were weighed and placed in a large heat-resistant container. I prepared 5 of the same item. 0.9 g each of the high-concentration sodium acetate-containing brewed vinegars of Reference Examples 1 to 5 were added to each of five test groups, that is, Comparative Example 1, Comparative Example 2, Comparative Example 3, Example 1, and Example 2. After soaking for 30 minutes, the rice was cooked at 130° C. for 30 minutes in a steam convection oven (Hoshizaki Denki). Steam for 10 minutes, transfer 100 g of cooked rice to a tray with a lid, inoculate Gram-negative bacillus separated from commercially available white rice to 10 CFU (10 CFU/g) per 1 g of white rice, store at 25 ° C. viable count was measured. Table 3 shows the results.

Preparation and storage tests were also conducted on white porridge in the same manner as in the sensory test. That is, prepare a small pot in which 200 g of water is added to 140 g of white rice, add 1.3 g each of the shelf life improving agent of Reference Examples 1 to 5 (0.38% of the total amount) to this pot, and heat for 15 minutes. and made porridge. After cooling down, gram-negative bacilli separated from commercially available white rice were inoculated at 10 CFU per 1 g of porridge and stored at 25° C., and the number of viable bacteria was measured over time.

Comparative Example 1 (Reference Example 1) spoiled after 72 hours. Comparative Example 2 (Reference Example 2) was close to 10 ⁶ CFU/g after 72 hours. Unlike chilled storage, it is considered to be for 25°C storage. In general, when the concentration is close to 10 ⁶ CFU/g, it is judged to be on the verge of putrefaction. Therefore, Comparative Example 2 (Reference Example 2) was unacceptable in terms of storage stability. Example 1 (Reference Example 3), Example 2 (Reference Example 4), and Comparative Example 3 (Reference Example 5) were excellent in preservability of white rice, but Comparative Example 3 (Reference Example 5) had a sour taste. It was sensually impossible. Examples 1 and 2 with an A/B ratio of 0.15 to 0.21 were normal even after 72 hours, confirming an excellent preservative effect.

Concerning white porridge, Comparative Example 1 (Reference Example 1) had a harsh taste and was not acceptable, while Comparative Example 2 (Reference Example 2) had a sour and harsh taste, but spoiled after 72 hours. Comparative Example 3 (Reference Example 5) is sour and unacceptable. Example 1 (Reference Example 3) and Example 2 (Reference Example 4) with an A/B ratio of 0.15 to 0.21 were normal even after 72 hours, confirming an excellent preservation effect.

2. Effect of acetic acid on flavor of sodium acetate-containing brewed vinegar (part 2)
(1) Preparation of 15% by weight sodium acetate-containing brewed vinegar In the same manner as the preparation of 20% by weight high acidity brewed vinegar containing sodium acetate-containing brewed vinegar, this time 15% by weight high acidity brewed vinegar is used to prepare acetic acid. A Na-containing brewed vinegar was prepared. Preparation data are shown in Table 4 in Reference Examples 6-9.

(2) Sensory test Table 5 shows the results of the sensory test of the sodium acetate-containing brewed vinegar prepared based on Table 4. A sensory test was performed in the same manner as in 1(2). In Reference Examples 6 to 9, the amount of the shelf life improver added was 0.9×(20/15)=1.2% in terms of uncooked rice. Among the preparations of Reference Examples 6 to 9, References 7 and 8 were favorable in both sourness and harshness (acceptable). That is, the acetic acid concentration after neutralization was in the range of 2.6 to 3.3, and the Na acetate concentration was in the range of 17 to 16%. The ratio (A/B) of residual acetic acid after neutralization to Na acetate produced by neutralization in the acceptable preparations was in the range of 0.15 to 0.21.

(3) Preservation test of cooked rice The shelf life improving agents for cooked rice of Reference Examples 6 to 9 in Table 4 were subjected to a preservation test of white rice. The storage test was performed in the same manner as in 1(3). Table 6 shows the results.

In Comparative Example 4 (Reference Example 6), the effect of preserving cooked rice was weak. Example 3 (Reference Example 7), Example 4 (Reference Example 8), and Comparative Example 5 (Reference Example 9) were excellent in preservability of white rice, but Reference Example 9 had a sour taste and was sensory impossible. there were. Examples 3 and 4 with an A/B ratio of 0.15 to 0.21 were normal even after 72 hours, confirming an excellent preservative effect.

3. Effect of acetic acid on flavor of Na acetate-containing brewed vinegar (Part 3)
(1) Preparation of 10% Na Acetate-Containing Brewed Vinegar Using the same method as the preparation of 1 (1) 20% high acidity brewed vinegar containing sodium acetate-containing brewed vinegar, this time using 10% high acidity brewed vinegar. A sodium acetate-containing brewed vinegar was prepared. Table 7 shows the preparation data of Reference Examples 10 to 13.

(2) Sensory test Table 8 shows the results of the sensory test of the sodium acetate-containing brewed vinegar prepared based on Table 7. A sensory test was performed in the same manner as in 1(2). Among the preparations of Reference Examples 10 to 13, Reference Examples 11 and 12 were favorable in terms of both sourness and harshness (acceptable). That is, the acetic acid concentration after neutralization was 1.7 to 2.2% by weight , and the Na acetate concentration was 11% by weight . The A/B ratio of acceptable preparations ranged from 0.15 to 0.21.

(3) Preservation test of cooked rice The shelf life improving agents for foods of Reference Examples 10 to 13 in Table 7 were subjected to a preservation test of white rice. The storage test was performed in the same manner as in 1(3). In Reference Examples 10 to 13, the additive amount of the shelf-life improver was 0.9×(20/10)=1.8% in terms of uncooked rice. Table 9 shows the results.

Comparative Example 6 (Reference Example 10) had a weak effect of preserving white rice. Example 5 (Reference Example 11), Example 6 (Reference Example 12), and Comparative Example 7 (Reference Example 13) were excellent in the preservability of white rice, but Comparative Example 7 (Reference Example 13) had a sour taste. It was sensually impossible. Example 5 with an A/B ratio of 0.15 and Example 6 with an A/B ratio of 0.21 were normal after 72 hours.

Table 10 summarizes the results of Tables 1 to 9. In this test, an attempt was made to improve the harsh taste of brewed vinegar containing high-concentration Na acetate produced by neutralization of high-acidity brewed vinegar. A high-concentration sodium acetate-containing brewed vinegar was prepared from 10 to 20% by weight of high-acidity brewed vinegar (three levels of high-acidity brewed vinegar of 10, 15, and 20% by weight ), and a sensory test was conducted. In addition, the ratio of residual acetic acid (A) to generated Na acetate (B) was investigated.

Through the preparation of Reference Examples 1 to 13, the test of the effect of improving the shelf life of cooked rice, and the sensory test, it became clear that (1) a small amount of acetic acid had the effect of masking the harsh taste of Na acetate: (2) The allowable range of harsh taste of Na acetate was 0.15 or more in terms of A/B ratio: (3) The allowable range of acidity was 0.21 or less in terms of A/B ratio. Regardless of the concentration of the brewed vinegar, the A/B ratio ranged from 0.15 to 0.21 in terms of both harshness and sourness.

That is, the high-concentration Na acetate-containing brewed vinegar of the present invention leaves a small amount of acetic acid when neutralizing 10 to 20% by weight of high-acidity brewed vinegar, and the amount is the concentration ratio of residual acetic acid and generated Na acetate. In the range of 0.15 to 0.21, it was found that the harsh taste of Na acetate is reduced and the effect of improving the shelf life of cooked rice is exhibited. Even if the acidity of the high-acidity brewed vinegar is less than 10% by weight or more than 20% by weight , the ratio of acetic acid/Na acetate is within the range of 0.15 to 0.21 by mass . the purpose of is achieved.

Claims (6)

A high-concentration sodium acetate-containing brewed vinegar obtained by partially neutralizing acetic acid contained in high-acidity brewed vinegar having an acidity in the range of 10 to 20% by weight with an inorganic sodium salt, wherein the ratio of acetic acid/sodium acetate is A shelf life improving agent for cooked rice, characterized by containing brewed vinegar containing high-concentration sodium acetate in a mass ratio of 0.15 to 0.21. The shelf life improving agent for cooked rice according to claim 1, wherein the inorganic sodium salt is sodium hydrogen carbonate or sodium carbonate. The shelf life improving agent for cooked rice according to claim 1 or 2, wherein said high-concentration sodium acetate-containing brewed vinegar is liquid. 3. The shelf life improving agent for cooked rice according to claim 1 or 2, wherein said high-concentration sodium acetate-containing brewed vinegar is powdery. Furthermore, red pepper extract, pectin hydrolyzate, hop extract, protamine, polylysine, nisin, egg white lysozyme, licorice extract; betaine, glycine, alanine; lactic acid, citric acid, malic acid, fumaric acid, adipic acid, succinic acid, The cooked rice according to claim 4 , containing at least one selected from the group consisting of gluconic acid and inorganic salts of these organic acids; calcium acetate, potassium acetate, lower fatty acid esters, sugar esters; vitamin B1 lauryl sulfate; A similar shelf life improver. A method for improving the shelf life of cooked rice, which comprises adding the shelf life improving agent for cooked rice according to any one of claims 1 to 5 to the cooked rice.