JP4469641B2 - Frozen food production method and obtained frozen food - Google Patents

Description

  The present invention relates to a method for producing a frozen food having excellent storage stability after thawing and a frozen food having improved storage stability.

  In recent years, frozen foods are often used in bento dishes such as convenience stores. Frozen foods, such as vegetables and fish shellfish, have limited harvest and landing periods, but they can be supplied throughout the year by freezing, and convenience stores can be used to produce products with consistent quality at a controlled factory. It has come to be widely used for lunch box side dish for home use.

  In the case of fresh vegetables, frozen foods are usually cut and adjusted after harvesting, blanched with salt water, individually frozen, weighed and packaged. For the purpose of preventing denaturation during freezing and improving the texture after thawing, a method of immersing in a sugar solution (see JP-A-5-103587) or a method of immersing in a mixed solution of sugar and inorganic salts, sugar and ethanol ( JP-A-4-27375), a method of heating in a calcium solution (see JP-A-8-140570), or a method of immersing in a urea solution (see JP-A-2001-224304) has been proposed. . Furthermore, a method of improving the quality of frozen food by sequentially performing a blanching step, a dehydration step, and a freeze denaturation prevention step (JP-A-8-280325) has also been proposed.

  In order to improve the freezing tolerance of squid in fish and shellfish, a method (Japanese Patent Laid-Open No. 2003-144100) is proposed in which the pH is adjusted to 8.5 to 11.5 by contacting with trehalose and salt. A method of covering with a high-strength elastic film capable of passing a projection group of shrimp or squid crustaceans (JP-A-7-327587) has also been proposed.

  However, no proposal has been made for improving microbiological shelf life after thawing of frozen foods. In general, frozen foods that have been cooked normally only last for about a day at room temperature.

At present, in a lunch box for convenience stores, bacteriostatic treatment is performed at the time of blanching for the purpose of keeping it for about 2-3 days at room temperature. For frozen foods that have not been bacteriostatically treated at the time of blanching, the shelf life is improved by re-cooking such as blanching using a bacteriostatic agent upon thawing. In such frozen foods, the problem is that the texture of vegetables is impaired by blanching twice before freezing and after thawing. In addition, even in frozen food processed with bacteriostatic agents at the time of blanching before freezing, after thawing and opening, when used for lunch, etc., secondary contamination by microorganisms may occur, It is difficult and difficult to keep for 2-3 days.
JP-A-5-103587 JP-A-4-27375 JP-A-8-140570 JP 2001-224304 A JP-A-8-280325 JP 2003-144100 A Japanese Patent Laid-Open No. 7-327587

  This invention makes it a subject to improve the shelf life after thawing | decompression of frozen food, and to provide the manufacturing method which has preservability, and the frozen food which has preservability for about 2 to 3 days at normal temperature.

As a result of diligent research to solve the above-mentioned problems, the present inventors treated fresh vegetables and fish shellfish with a bacteriostatic agent twice at the time of blanching and freezing. The present inventors have found that secondary contamination can be suppressed and can be stored while maintaining freshness at room temperature, and the present invention has been completed.

  That is, the present invention is a frozen food characterized in that fresh food is blanched with high-temperature water containing a bacteriostatic agent, drained, cooled, packaged with a bacteriostatic agent aqueous solution, sealed and then frozen. A production method is provided, and a frozen food subjected to such treatment is provided.

  According to the present invention, the bacteriostatic agent treatment at the time of blanching and freezing can suppress the propagation of microorganisms after thawing, can maintain the freshness of fresh food, and takes about 2 to 3 days at room temperature. The manufacturing method of the frozen food which has the preservability of this can be provided. In addition, frozen foods that are heated only at the time of cooking (branching) by the production method of the present invention have particularly little damage to the texture of fresh foods.

  In the present invention, the fresh food is not particularly limited, but is suitable for fresh vegetables and shellfish, for example. Examples of fresh vegetables include broccoli, quinusaya, green beans, rape blossoms, green peas, and other vegetables often used for lunch boxes and salads. Examples of fish shellfish include shrimp, squid, octopus, clams and the like.

  The bacteriostatic agent can be used without particular limitation as long as it is used for the preservation of food, but preferably shirako protein, polylysine, nisin, decomposed pectin, hop extract, chili extract, licorice oily extract , Egg white lysozyme, acetic acid, sodium acetate, lactic acid, sodium lactate, glycine, alanine, calcined calcium, or glycerin fatty acid ester.

  Among these, shirako protein includes white protein as a preservative extracted and purified from white silkworm. Nisin is an antibacterial protein produced by the lactic acid bacterium Lactococcus lactis subsp. Lactis and is a kind of bacteriocin, which is commercially available from Aprin Barrett. As degraded pectin, degraded pectin can be raised as a preservative obtained by degrading citrus-derived pectin with an enzyme.

Examples of the hop extract include an extract obtained by alcohol extraction from hop spikelets used in beer production. As a chili extract, an aqueous extract from the peel of a solanaceae chili can be mentioned, and as an licorice oily extract, an extract extracted from legume licorice roots and rhizomes with ethanol or an organic solvent can be cited. Can do.

  Examples of the egg white lysozyme include egg white lysozyme (hereinafter sometimes simply referred to as lysozyme) as a shelf life extractant extracted and purified from egg white. Examples of acetic acid include glacial acetic acid and brewed vinegar. Examples of lactic acid include d, l-lactic acid, fermented lactic acid, and lactic acid bacteria fermented moromi. Examples of calcined calcium include those obtained by calcining shells, eggshells, or animal bones. Examples of glycerin fatty acid esters include esters of medium chain fatty acids and glycerin in fats and oils.

  Although the concentration of the bacteriostatic agent varies depending on the type of bacteriostatic agent, it cannot be generally stated, but is preferably 0.0001 to 10%, more preferably 0.001 to 3% on a weight basis. If the concentration of the bacteriostatic agent is less than 0.0001%, sufficient preservability cannot be imparted. On the other hand, if it exceeds 10%, the tissue may become weak or the taste may be affected.

As the bacteriostatic agent, the same one as that added to the high temperature water during blanching and the one added to the aqueous solution used before freezing is preferable, but another bacteriostatic agent may be used. The bacteriostatic agent concentration in high-temperature water and the bacteriostatic agent concentration in the water may be the same as long as both are the same bacteriostatic agent. Since the effect is different, it may be used at an appropriate concentration.

  The method for producing frozen food of the present invention uses high-temperature water containing a bacteriostatic agent as high-temperature water at the time of blanching, and when packaging the food subjected to blanching treatment for frozen storage, A frozen food can be produced by the same operation as the conventional method for producing a frozen food, except that the aqueous bacterial solution is packaged at the same time.

  The present invention will be described more specifically with reference to the following examples. However, the scope of the present invention is not limited thereby. In the examples, “%” is% by weight.

[Example 1]
After cutting and adjusting raw broccoli and washing with water, boiled water containing 0.8% shirako preparation (impact A, Asama Kasei Co., Ltd., 4% shirako protein white) and 1% salt It was added, boiled for 1 minute, boiled, and drained. After taking the rough heat, the polyethylene bag was filled with boiled broccoli and 0.8% aqueous solution (feed solution) of herb preparation, sealed and frozen. While the frozen product was frozen, it was boiled for 1 minute together with the bag, opened, drained, and thawed broccoli was obtained. The thawed broccoli was stored at 25 ° C. for 2 days and at 15 ° C. for 3 days, and the number of viable bacteria (cfu / g) was measured over time. The measurement method was a standard plate culture method.
The results are shown in Table 1.

[Example 2]
A storage test was conducted in the same manner as in Example 1 except that the frozen product was not thawed, only thawed, opened and drained. The results are also shown in Table 1.

[Comparative Example 1]
A storage test was conducted in the same manner as in Example 1, except that the shirako preparation was not added to the water during blanching, the shirako preparation aqueous solution was not filled, and 1% saline was used as boiled water for the frozen product. The results are also shown in Table 1.

(Table 1)
(Storage at 25 ° C) 0 hours 24 hours later 48 hours later
Example 1 <10 <10 3.8 × 10 ²
Example 2 3.7 × 10 5.5 × 10 ² 9.1 × 10 ⁶
Comparative Example 1 1.2 × 10 ² 2.9 × 10 ⁶ Corruption
(Storage at 15 ° C) 0 hours 24 hours 48 hours 72 hours
Example 1 <10 <10 <10 <10
Example 2 3.7 × 10 4.2 × 10 1.8 × 10 ² 6.9 × 10 ³
Comparative Example 1 1.2 × 10 ² 2.1 × 10 ³ 4.1 × 10 ⁶ Corruption

[Example 3]
The washed raw Kinusaya is washed with water, then poured into a boiled water containing 1% lysozyme preparation (OP-5, Asama Kasei Co., Ltd. containing 0.5% egg white lysozyme) and 1% salt. Boiled for a minute and then drained. After taking rough heat, the polyethylene bag was filled with a liquid solution containing boiled Kinusaya and 1% aqueous solution of lysozyme, sealed, and frozen. The frozen product was boiled for 1 minute together with the bag, opened, drained, and thawed Kinusaya was obtained. The thawed Kinusaya was stored at 25 ° C. for 2 days and at 15 ° C. for 3 days, and the viable count was measured over time to evaluate the storage stability. The results are shown in Table 2 as the number of general viable bacteria.

[Example 4]
A storage test was conducted in the same manner as in Example 3 except that the frozen product was thawed only without being boiled, opened and drained. The results are also shown in Table 2.

[Comparative Example 2]
A storage test was conducted in the same manner as in Example 3 except that the lysozyme preparation was not added to the water during blanching, the lysozyme preparation aqueous solution was not filled, and 1% saline was used as the boiled water for the frozen product. The results are also shown in Table 2.

(Table 2)
(Storage at 25 ° C) 0 hours 24 hours later 48 hours later
Example 3 <10 <10 7.7 × 10 ⁴
Example 4 2.5 × 10 8.4 × 10 ³ 9.9 × 10 ⁶
Comparative Example 2 9.1 × 10 ² 2.9 × 10 ⁶ rot
(Storage at 15 ° C) 0 hours 24 hours 48 hours 72 hours
Example 3 <10 <10 <10 <10
Example 4 2.5 × 10 5.2 × 10 4.6 × 10 ² 8.1 × 10 ³
Comparative Example 2 9.1 × 10 ² 8.0 × 10 ³ 1.2 × 10 ⁷ Rot

[Example 5]
After streaking and washing with water, the kidney beans cut to 2-3 cm were put into a boiled water containing 2% glycine preparation (containing H-1, Asama Kasei Co., Ltd., 60% glycine) and 1% salt. , Boiled for 1 minute and then drained. After taking rough heat, a polyethylene bag was filled with a liquid solution containing boiled kidney beans and 1% glycine preparation (vs. kidney weight?), Sealed and frozen. The frozen product was boiled for 3 minutes, opened, drained, and thawed kidney beans were obtained. The thawed kidney beans were stored at 25 ° C. for 2 days and at 15 ° C. for 3 days, and the viable count was measured over time to evaluate the storage stability. The results are shown in Table 3 as the number of general viable bacteria.

[Example 6]
A storage test was conducted in the same manner as in Example 5 except that the frozen product was thawed only without being boiled, opened and drained. The results are also shown in Table 3.

[Comparative Example 3]
A storage test was conducted in the same manner as in Example 5, except that the glycine preparation was not added to the water during blanching, the glycine preparation was not added to the solution, and 1% saline was used as boiled water for the frozen product. The results are also shown in Table 3.

(Table 3)
(Storage at 25 ° C) 0 hours 24 hours later 48 hours later
Example 5 <10 1.4 × 10 ² 4.8 × 10 ²
Example 6 1.1 × 10 3.9 × 10 ⁴ 8.7 × 10 ⁷
Comparative Example 3 1.9 × 10 ² 5.6 × 10 ⁶ rot
(Storage at 15 ° C) 0 hours 24 hours 48 hours 72 hours
Example 5 <10 <10 <10 <10
Example 6 1.1 × 10 6.8 × 10 ² 7.2 × 10 ³ 9.6 × 10 ⁴
Comparative Example 3 1.9 × 10 ² 1.7 × 10 ³ 9.6 × 10 ⁶ Rot

[Example 7]
Shrimp (black tiger) with the head and feet taken off, the shell removed and the back intestine removed, was soaked in an aqueous solution of 1% sodium polyphosphate and 1% sodium chloride in a refrigerator for 4 hours. After draining, add water containing 1% lysozyme preparation (Lunchguard AP, Asama Kasei Co., Ltd., containing 0.5% egg white lysozyme) to the boil, boil for 3 minutes and boil for 3 minutes. did. After removing the rough heat, the mushroom was filled in a polyethylene bag with a liquid solution containing 1% of a lysozyme preparation, sealed, and frozen. The frozen product was boiled for 3 minutes, opened, drained, and thawed shrimp. The obtained thawed shrimp was stored at 25 ° C. for 2 days and at 15 ° C. for 3 days, and the number of general viable bacteria was measured over time to evaluate the storage stability. The results are shown in Table 4.

[Example 8]
A storage test was conducted in the same manner as in Example 7 except that the frozen product was thawed only without being boiled, opened and drained. The results are also shown in Table 4.

[Comparative Example 4]
A storage test was conducted in the same manner as in Example 7, except that the lysozyme preparation was not added to the water during blanching, the lysozyme preparation was not added to the solution, and 1% saline was used as boiled water for the frozen product. The results are also shown in Table 4.

(Table 4)
(Storage at 25 ° C) 0 hours 24 hours later 48 hours later
Example 7 <10 <10 <10
Example 8 2.7 × 10 4.9 × 10 ³ 2.7 × 10 ⁶
Comparative Example 4 4.0 × 10 ² 6.3 × 10 ⁶ rot
(Storage at 15 ° C) 0 hours 24 hours 48 hours 72 hours
Example 7 <10 <10 <10 8.6 × 10
Example 8 2.7 × 10 5.1 × 10 3.3 × 10 ² 6.5 × 10 ⁴
Comparative Example 4 4.0 × 10 ² 5.5 × 10 ⁴ 1.1 × 10 ⁷ Corruption

[Example 9]
The viscera were removed from the true octopus, thoroughly soaked with salt, and washed with water. After draining, water containing 1.2% of pepper extract preparation (Spanish L, Asama Kasei Co., Ltd., containing 2% of pepper extract) was added to the boiled water and boiled for 1 minute. After draining. After taking the rough heat, the slice was cut, filled into a polyethylene bag with a solution containing 1.2% of the pepper extract formulation, sealed, and frozen. The frozen product was boiled for 3 minutes together with the bag, opened and drained to obtain a thawed octopus slice. The obtained thawed octopus slices were stored at 25 ° C. for 2 days and at 15 ° C. for 3 days, and the viable count was measured over time to evaluate the storage stability. The results are shown in Table 5.

[Example 10]
A preservation test was conducted in the same manner as in Example 9 except that the frozen product was not thawed, only thawed, opened and drained. The results are also shown in Table 5.

[Comparative Example 5]
Preservation test in the same manner as in Example 9 except that no pepper extract preparation was added to the water during blanching, no pepper extract preparation was added to the liquid, and 1% saline was used as boiled water for the frozen product. Went. The results are also shown in Table 5.

(Table 5)
(Storage at 25 ° C) 0 hours 24 hours later 48 hours later
Example 9 <10 <10 <10
Example 10 2.2 × 10 3.6 × 10 ³ 7.1 × 10 ⁶
Comparative Example 5 1.0 × 10 2.4 × 10 ⁶ Corruption
(Storage at 15 ° C) 0 hours 24 hours 48 hours 72 hours
Example 9 <10 <10 <10 8.6 × 10
Example 10 2.2 × 10 8.0 × 10 3.5 × 10 ² 4.1 × 10 ³
Comparative Example 5 1.0 × 10 5.8 × 10 6.9 × 10 2.1 × 10 ⁵

[Example 11]
The clam was soaked in 3% saline solution, and left in the refrigerator for 2-3 hours. After washing the outside of the shell well with water, add 1% of the decomposed pectin preparation (Neupectin L, Asama Kasei Co., Ltd., 28% decomposed pectin) to the boil, and boil for 1 minute to boil And then drained. After taking the rough heat, the dehulled flesh was filled in a polyethylene bag with a liquid solution containing 1% of a degraded pectin preparation, sealed, and frozen. The frozen product was boiled for 3 minutes together with the bag, opened, drained, and a clam was obtained using a thaw cake. The clams were stored for 2 days at 25 ° C. and for 3 days at 15 ° C. with the obtained thaw cake, and the viable count was measured over time to evaluate the storage stability. The results are shown in Table 6 as the number of general viable bacteria.

[Example 12]
A storage test was conducted in the same manner as in Example 11 except that the frozen product was thawed only without being boiled, opened and drained. The results are also shown in Table 6.

[Comparative Example 6]
A storage test was conducted in the same manner as in Example 11 except that no decomposed pectin preparation was added to the water during blanching, no decomposed pectin preparation was added to the liquid, and 1% saline was used as boiled water for the frozen product. It was. The results are also shown in Table 6.

(Table 6)
(Storage at 25 ° C) 0 hours 24 hours later 48 hours later
Example 11 4.4 × 10 7.2 × 10 ² 2.5 × 10 ⁴
Example 12 3.8 × 10 4.2 × 10 ² 6.8 × 10 ⁷
Comparative Example 6 8.0 × 10 ² 9.9 × 10 ⁷ Corruption
(Storage at 15 ° C) 0 hours 24 hours 48 hours 72 hours
Example 11 4.4 × 10 7.3 × 10 5.2 × 10 ² 1.4 × 10 ³
Example 12 3.8 × 10 7.1 × 10 ² 8.5 × 10 ³ 2.3 × 10 ⁴
Comparative Example 6 8.0 × 10 ² 2.1 × 10 ³ 4.1 × 10 ⁶ Corruption

As shown above, in the product of the present invention, those that have undergone secondary boiling are 10 ⁵ cells / g or less in terms of the number of general viable bacteria that are considered to be spoilage even when stored at 25 ° C., 2 days and 15 ° C. for 3 days It was. Moreover, since the number of general viable bacteria can be suppressed even if the secondary boil time is relatively short, the texture was not impaired.

In addition, even in the case where secondary boiling was not performed, the present invention had a number of viable bacteria of 10 ⁵ / g or less as a measure of spoilage even when stored at 25 ° C., 1 day and 15 ° C. for 3 days. . Thus, since the number of general viable bacteria can be suppressed without secondary boiling, the food texture is closer to that of fresh food.

Claims (5)

A method for producing frozen food, which comprises blanching fresh food with high-temperature water containing a bacteriostatic agent, draining, cooling, packaging and sealing with an aqueous bacteriostatic agent solution, and then freezing. The method for producing a frozen food according to claim 1, wherein the fresh food is a fresh vegetable or a fresh fish shellfish. The bacteriostatic agent is shirako protein, polylysine, nisin, decomposed pectin, hop extract, pepper extract, licorice oily extract, egg white lysozyme, acetic acid, sodium acetate, lactic acid, sodium lactate, glycine, alanine, calcined calcium The manufacturing method of the frozen food of Claim 1 or 2 containing 1 type, or 2 or more types chosen from the group which consists of glycerol fatty acid ester. The method for producing a frozen food according to any one of claims 1 to 3, wherein the concentration of the bacteriostatic agent is 0.0001 to 10% by weight. The frozen food obtained by the manufacturing method of any one of Claims 1-4.