JP3190297B2 - Heat treatment method for vegetables - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heat-treating vegetables as a pretreatment when heat-sterilizing vegetables. More specifically, the present invention relates to a method for heat-treating vegetables, which can maintain good taste and texture of vegetables even when heat-treated for sterilization.

[0002]

2. Description of the Related Art Conventionally, for example, vegetables used as ingredients for preservative foods such as retort foods have a significantly softened texture due to heat sterilization treatment. Processing has been done. As the above treatment, for example, a method of storing vegetables in warm water at 40 to 75 ° C. (Japanese Patent Laid-Open No. 54-107542), or a method in which vegetables are immersed in a calcium solution,
A method in which the temperature is raised to 0 ° C. and held for a certain time (Japanese Patent Application Laid-Open
No. 237957) has been proposed. According to these methods, vegetables which can maintain a good texture even when subjected to heat treatment can be obtained, but there is a problem that the taste of the vegetables is reduced.

A method has also been proposed in which the surface of vegetables is burnt or dried with superheated steam or sterile hot air to maintain the texture (Japanese Patent Laid-Open No. 8-116865). According to this method, the umami of vegetables can be maintained satisfactorily, but the burnt odor is felt from the burnt portion, or the texture of the dry film portion is different from the original texture of vegetables. Was unnatural. That is, in the above-mentioned conventional technology, vegetables which can maintain the original umami of vegetables and the natural texture of the vegetables in a good condition cannot be obtained.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for heat-treating vegetables, which can maintain the original taste and texture of vegetables even when the vegetables are heat-sterilized. I do.

[0005]

Means for Solving the Problems The present inventor has determined that heating a vegetable in hot water is a cause of loss of the flavor of the vegetable. And obtained the finding that the above-mentioned problem of the outflow of umami can be solved by using steam at 60 to 90 ° C. instead of hot water. It has been found that when steam is brought into contact with vegetables, the surface of the vegetables is dried and the texture of the vegetables becomes unnatural, but at this time, the temperature of the steam is reduced to 60 to 90 ° C. In this case, the present inventors have found that the taste of vegetables can be maintained and the good texture of vegetables can be maintained, and the present invention has been completed.

[0006] That is, the present invention is a heat treatment method characterized in that when heating vegetables, the vegetables are brought into direct contact with steam at 60 to 90 ° C beforehand. Further, the present invention is a heat treatment method characterized by performing the above steam treatment after immersing vegetables in a calcium solution. Examples of the vegetables used in the present invention include potato, sweet potato, taro, carrot, radish, pumpkin, onion, cabbage, kidney bean, lotus root, Chinese cabbage, celery, eggplant and the like. INDUSTRIAL APPLICABILITY The present invention is effective mainly for vegetables used as ingredients for preservative foods, but is not limited to these vegetables, and is effective for many vegetables.

In the present invention, raw vegetables are used for these vegetables, but those which are slightly dried, frozen or thawed after freezing may be used. In using the vegetables, the vegetables are washed and, if necessary, peeled, and used as they are or cut to a predetermined size. The vegetables may be subjected to preliminary heating (branching) for the purpose of inactivating the enzyme, but it is desirable that the time be short in order to prevent a reduction in the umami of the vegetables.

[0008] Among vegetables, vegetables having a higher calcium content can obtain higher effects. Vegetables that are said to have a high calcium content include kidney beans, carrots, radish, burdock, Chinese cabbage, etc., but the calcium content of the vegetables at the time of performing the steam treatment is included in 100 g of the vegetables. The amount is preferably 5 mg or more, more preferably 20 mg or more.

[0009] Vegetables having a high calcium content can more effectively prevent tissue softening than vegetables having a low calcium content because calcium forms vegetable tissue during steam treatment. This is thought to be due to the effect of acting on pectin, suppressing the degradation of pectin, and thereby retaining vegetable tissue. In vegetables having a high calcium content, it is considered that calcium is distributed throughout the tissue, and vegetables having a more natural texture can be obtained. On the other hand, in vegetables that have been subjected to the calcium solution immersion treatment, it is considered that more calcium is unevenly distributed in the surface layer, and the tissue in the surface layer tends to be more strongly retained than in the vegetable.

[0010] When the treatment of the present invention is applied to vegetables having a low calcium content, the vegetables may be immersed in a calcium salt solution in advance. As the calcium salt solution, an aqueous solution in which a calcium salt such as calcium lactate or calcium chloride is dissolved is used, and the calcium salt concentration is preferably in the range of 0.5 to 5% by weight. The immersion time of the vegetables in the calcium salt solution is not particularly limited as long as the amount of calcium contained in the vegetables is sufficient, but if the immersion time is long, the taste of the vegetables tends to flow out It is in. Therefore, it is generally preferable to immerse vegetables in a calcium salt solution for about 2 hours.

[0011] The temperature of the calcium salt solution for immersing vegetables is preferably 5 to 40 ° C. In addition, if the immersion treatment is performed under a reduced pressure atmosphere, the immersion time can be shortened, so that even the outflow of umami during the immersion treatment with the calcium salt solution can be prevented more reliably in a preferred method. is there. In the present invention, steam treatment is performed by bringing steam into direct contact with the vegetables. In this steam treatment, the entire surface of the individual vegetable (for example, for each cut piece) is directly in contact with the steam. Contacting
It is preferable from the viewpoint of maintaining a uniform texture and preventing loss of umami.

[0012] As a method of the steam treatment, for example, a method of filling vegetables into an upper opening retainer having a large number of holes on the bottom surface and putting the vegetables into a closed atmosphere filled with steam together with the retainers, and a method of treating the vegetables in the retainer. On the other hand, there is a method of injecting steam from above and / or from below. In the steam treatment of the present invention, the temperature of the steam is 60-9.
0 ° C. More preferably, it is 70 to 80 ° C. If the temperature of the steam is lower than 60 ° C., not only the texture of the vegetables cannot be maintained well, but also the activity of enzymes contained in the vegetables will promote the browning of the vegetables, causing the vegetables to fade. A problem arises in that the vegetables become shaded. On the other hand, when the temperature exceeds 90 ° C., vegetables having a good texture cannot be obtained. That is, when the temperature exceeds 90 ° C., the vegetable tissue is softened by the heat, so that it becomes crunchy.

As a means for adjusting the steam temperature to 60 to 90 ° C., for example, a method of introducing normal pressure steam into a closed atmosphere and depressurizing the atmosphere, or a method in which steam at 100 ° C. or more and Of air, preferably air at 5 to 50 ° C. The steaming time is preferably 5 to 100 minutes, more preferably 10 minutes.
~ 50 minutes. If the steaming time is less than 5 minutes, the texture of vegetables tends to be reduced by heat treatment such as sterilization or cooking. On the other hand, when the time exceeds 100 minutes, the vegetables tend to be hard to feel good chewy.

In the present invention, the above-mentioned steam treatment is performed as a pre-treatment when heating and sterilizing vegetables. And the umami is not reduced. Heat sterilization conditions include 0.5 to 105 ° C. and 140 ° C.
To 120 minutes, more preferably 115 to 1
35 ° C. for 2-40 minutes. As a method of heat sterilization, steam-processed vegetables are filled in a retort pouch and sealed, and retort sterilization is performed under the above-mentioned heat sterilization conditions. Or subjected to heat sterilization treatment of liquid material such as soup,
There is a method of filling the container with the vegetables and the liquid under a sterile atmosphere and sealing the container.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to embodiments.

EXAMPLE 1 An upper stainless steel retainer having a large number of small holes on the bottom face was placed on 100 g of carrot pieces cut in the shape of a 20 mm × 20 mm × 20 mm die, taking care not to overlap the carrot pieces as much as possible. Line up. Next, the retainer is disposed in a sealable room having a steam introduction pipe above, and after sealing the room,
By mixing 10 ° C steam and room temperature air,
Steam whose temperature has been adjusted to ° C. is introduced into direct contact with the carrot pieces. The time required for this steam treatment was
30 minutes.

Next, the chamber is opened to take out the retainer, and the steam-treated carrot contained in the retainer is filled and sealed in a retort pouch, subjected to a retort sterilization treatment at 121 ° C. for 15 minutes, and subjected to a retort sterilization. Carrot was obtained. Thereafter, the retort pouch was opened, and the carrots that had been sterilized by the retort were eaten. As a result, the taste of the carrot was favorably maintained, and the texture also maintained a good hardness.

[0017]

Example 2 100 g of potato pieces cut into a size of 20 mm × 20 mm × 20 mm are immersed in a calcium lactate solution (2% by weight) at 25 ° C. for 2 hours. Next, a steam treatment is performed under the same conditions as in the first embodiment. Then, the steamed potato pieces were filled in a retort pouch and sealed, and
A retort sterilization treatment was performed at 1 ° C. for 15 minutes to obtain a retort-sterilized potato. When the retort pouch was opened and the retort-sterilized potato was eaten, the umami of the potato was well maintained, and the texture also maintained good hardness.

[0018]

COMPARATIVE EXAMPLE 1 100 g of carrot pieces of 20 mm × 20 mm × 20 mm were placed in a 5% aqueous solution of calcium lactate (2% by weight).
Immersion treatment for 15 hours in this
The temperature was raised to ° C., and the temperature was maintained for 1 hour to obtain a carrot treated with calcium. Next, the calcium-treated carrot was filled in a retort pouch and sealed.
The mixture was subjected to a retort sterilization treatment for 15 minutes to obtain a retort-sterilized carrot. When the retort pouch was opened and the carrots that had been sterilized by the retort were eaten, it was confirmed that the carrots had good hardness, but the umami of carrots was hardly felt. The difference was remarkably recognized as compared with the carrot of Example 1 in which umami was well maintained.

[0019]

[0020]

[0021]

[0022]

According to the present invention, even if a heat treatment is performed for the purpose of sterilization, it is possible to maintain good umami, and to maintain good texture as vegetables even in the texture. You can get vegetables that you can.

Continuation of the front page (56) References JP-A-8-140618 (JP, A) JP-A-2-13346 (JP, A) JP-A-64-43164 (JP, A) JP-A-61-254139 (JP) JP-A-60-192566 (JP, A) JP-A-57-22661 (JP, A) JP-A-55-135566 (JP, A) JP-A-55-71469 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) A23L 1 / 212,1 / 214,1 / 216

Claims (4)

(57) [Claims] 1. A method for heat-treating vegetables, which comprises bringing steam of 60 to 90 ° C. directly into contact with the vegetables before heat-sterilizing the vegetables. 2. The method for heat-treating vegetables according to claim 1, wherein steam at 60 to 90 ° C. is brought into direct contact for 5 to 100 minutes. 3. When heat-sterilizing vegetables, the vegetables are immersed in a calcium solution beforehand, and
A method for heat-treating vegetables, comprising directly contacting steam at 90 ° C. 4. Heat sterilization conditions: 105-140 ° C.
2. The method according to claim 1, wherein the time is 0.5 to 120 minutes.
4. The method for heat-treating vegetables according to any of Ishi 3 above.