JP4319209B2 - Method for producing freeze-dried green onion - Google Patents

Description

  The present invention relates to a method for producing a round cut green onion, among freeze-dried green onions.

  Traditionally, dried green onions have been used as ingredients for instant foods such as instant miso soup and instant noodles and many other foods. Examples of methods for drying these green onions include a hot air drying method, a freeze drying method, a vacuum drying method, and a microwave drying method.

  In particular, the freeze-drying method has the advantage that there is no change in form due to drying, there is no change in the components during drying, and it can be dried while retaining its color, taste, nutritional components, etc. Often. To date, various vegetable freeze-drying methods have been disclosed (for example, Patent Documents 1 to 5).

JP-A-57-39733 JP 05-123100 A Japanese Patent Laid-Open No. 06-233651 Japanese Patent Laid-Open No. 10-309161 JP, 2001-178358, A These methods have a wide range of vegetables as an object to freeze-dry, and are not freeze-drying methods for specific vegetables.

  However, vegetables have different compositions and characteristics depending on the type. Therefore, when producing freeze-dried vegetables, there may be a problem inherent to the type of vegetable.

  In particular, in the case of a green onion, the leaf sheath of the green onion is differentiated into several leaves in its interior and has a layered structure. Therefore, when the leaf sheath of the green onion is cut into a ring shape, the youngest central leaf bud (core) and the multiple layers of leaf buds (green onion) surrounding it form a layered structure. In the conventional freeze-drying method, The phenomenon that the core part and the leek ring are separated and detached was observed.

  Thus, when a core part and a leek ring isolate | separate, an appearance problem will arise at the time of eating. In particular, when used for cup noodles, etc., if the freeze-dried leek green onion is not put into a sachet separately and directly put into the cup, the separated leek ring will be stored in the container when the product is transported. Due to vibration with noodles, the leek ring may break. In addition, when the cracked leek piece uses a plastic cup as a container, it may adhere to the inner surface of the cup due to static electricity. In this respect, if the chopped green onion maintains its form, cracks and the like are unlikely to occur, and the above-described problems are unlikely to occur.

  The freeze-dried green onion is an ingredient widely used in instant foods such as instant noodles and instant miso soup, and is expected to be widely used in the future, and is expected to be in great demand.

If it is possible to prevent separation of the core portion or the leek ring in such freeze-dried lasso, it is possible to avoid the inconveniences as described above, and to further develop the instant food.

Therefore, we aimed to develop a production method in which the core and the green onion ring are not separated even after freeze-drying in the production of freeze-dried green onion.

As a result of our earnest research,
A method for producing a freeze-dried leek green onion comprising the following steps:
A) the step of washing the raw green onions,
B) A step of cutting the raw green onion into a chopped state C) A step of holding the chopped green onion in a steam chamber at 85 ° C. to 100 ° C. for 15 seconds to 3 minutes and 45 seconds D) After being held in the steam chamber A method for producing a freeze-dried green onion comprising a step of freeze-drying a green onion,
Developed. Surprisingly, by using this production method, it is possible to prevent the discoloration and maintain the original color of white or green without any separation of the core and the green onion even in freeze-dried green onion. I found.

  The specific holding time in the steam chamber at 85 ° C to 100 ° C is 1 minute to 3 minutes and 45 seconds at 85 ° C, 45 seconds to 2 minutes and 30 seconds at 90 ° C, and 30 seconds to 1 minute at 95 ° C. 45 seconds, at 98 ° C., 15 seconds to 1 minute 30 seconds,

  Furthermore, it is possible to include a step of attaching saccharides to the chopped green onions after the step C and before the step D. By adding this step, damage of the chopped green onions after freeze-drying can be prevented. In addition to being able to prevent this further, it is possible to improve the restorability and texture.

In addition, it is possible to further prevent the separation of the core and the leek ring by including a step of immersing the leek after slicing in the gelatin solution after the B step and before the C step. I found it.

In a freeze-dried leek that is widely used for instant foods, it is possible to prevent the core portion or leek ring from being separated and to maintain a good color of leek. The freeze-dried green onion produced according to the present invention can be used for various foods. This is particularly useful when used for instant foods.

  Hereinafter, the contents of the invention will be described in detail according to the production process, but the present invention is not limited to this range.

─Process for cleaning raw green onions─
The raw material used in the present invention is a green onion that is a raw vegetable. For example, the types of green onions are white leek such as Senju leek, Kaga leek and Shimonita leek, blue leek (leaf leek) such as Kujo leek and Hakata universal leek, intermediate type such as super tsugi leek, red leek, It can be used for a wide range of applications, including sushi, asatsuki, and leek.

  In the present invention, the leaf sheath (2) of these green onions is used as shown in FIG. In the leaf sheath part of a green onion, it has differentiated into several leaves in its inside and has a layered structure. Accordingly, when the leaf sheath of the green onion is cut at a certain interval perpendicularly or obliquely with respect to the extending direction (when cut into a circular shape), the youngest leaf bud (core) (4) as shown in FIG. ) And a number of layers of leaf buds (green onion) (5) surrounding it, a layered structure is seen, and so-called ring-cut green onions forming this layered structure are the subject of the present invention.

  In the production of freeze-dried green onions, not only the leaf sheath part but also the leaf blade part is often produced, but even in such a case, the present invention includes a leek having a layered structure. Of course, it can be used.

  When the green onion is washed, it is washed with water or the like, but it is washed immediately after harvesting or after removing the root part and the tip part of the leaf blade part.

  Moreover, you may add the disinfection process by sodium hypochlorite in this process. In this case, for example, the green onion from which the roots and leaf blades have been removed is immersed in an aqueous solution of about 150 to 250 ppm of sodium hypochlorite for about 10 to 20 minutes. Wash.

─Cut the raw green onion into a round shape─
Next, the raw green onions are cut. As a cutting direction, in addition to a method of cutting perpendicularly to the direction of the green onions, the green onions may be cut obliquely. Specifically, the present invention can be used as long as the angle between the onion extension direction and the cut surface is about 25 ° or more.

  Cutting can be performed by hand cutting with a knife or knife, or a slicer. The cutting width may be a constant interval or may be changed. As a specific cutting width, it can be widely cut to about 2 mm to 30 mm, and particularly about 5 mm to 15 mm is preferable.

─ The process of immersing the chopped green onion in gelatin solution ─
In the present invention, a step of immersing the green onion in a gelatin solution after cutting the green onion into round shapes can be added. By passing through this process, gelatin can be infiltrated into the cut surface of the chopped green onion while dissolving the gelatin during heating in the subsequent steam chamber. It is possible to promote the binding between each other. This can further prevent the leek rings from being separated in conjunction with the subsequent blanching process.

  When immersing the chopped green onion in the gelatin solution, in addition to the method of immersing the entire chopped green onion in the gelatin solution tank, it is possible to immerse only one end of the cut surface of the circular chopped green onion. The concentration of the gelatin solution can be widely used from about 0.2% to 10.0%, and particularly preferably about 0.5% to 5.0%.

─Holding process in the steamhouse─
Next, the leek after slicing or the leek after immersing in gelatin solution is held in a steam chamber to perform blanching. In many cases, the blanching method is usually a method of immersing in hot water, but in the present invention, it is important to use steam.

  At the time of blanching, the separation of the core and the leek ring becomes a problem, and the color of the leek after lyophilization also becomes a problem in appearance. Usually, the leaf sheath of the green onion is white, but as a result of experiments by the present inventors, the branching is insufficient, or conversely, it tends to be browned when it is performed excessively.

  In addition, the leaf sheath portion in the vicinity of the leaf blade portion usually exhibits a green color, but there is a tendency that the branching is insufficient or, conversely, the green color fades when excessively performed.

  Therefore, in order to avoid these inconveniences, it is necessary to find the optimum temperature and holding time in the vapor chamber that prevents browning and fading while preventing the separation of the leek rings.

  As a result of various experiments, specific blanching conditions were not sufficiently heated at 80 ° C. or lower, and it was impossible to obtain sufficient separation and color of the rings. Moreover, since it is necessary to apply pressure at 100 ° C. or higher, special equipment is required. Therefore, it is preferable to use steam at 85 ° C to 100 ° C. Moreover, 90 to 95 degreeC is especially preferable from workability | operativity, such as adjustment of steam temperature and shortening of manufacturing time.

  Furthermore, the holding time in the steam chamber at each temperature is approximately 1 minute to 3 minutes 45 seconds at 85 ° C., preferably 1 minute 15 seconds to 3 minutes, and approximately 90 seconds to 90 minutes at approximately 45 seconds. 1 minute to 2 minutes and 15 seconds, preferably about 30 seconds to 1 minute and 45 seconds at 95 ° C, preferably 45 seconds to 1 minute and 30 seconds, and about 98 seconds to about 15 seconds to 1 minute and 30 seconds, preferably It was found to be 30 seconds to 1 minute 15 seconds.

  In addition, from the above results, the present inventors have examined that, in the slicing green onion, the core of the green onion after lyophilization and the green onion ring are not separated, and the range in which discoloration can be prevented and vivid green can be maintained. As shown in FIG. 3, it is found that the range is indicated by the oblique line surrounded by the solid line of ● ◆. Further, it is preferably a range surrounded by a dotted line of ◇.

  The holding time at each temperature is Y: holding time (seconds), and X: temperature in the vapor chamber.

It was found that can be approximated by. Therefore, temperatures other than 85 ° C., 90 ° C., 95 ° C., and 98 ° C. may be the holding time when applied to the above formula.

  In addition, about the mechanism which can prevent isolation | separation of a core part and a leek ring by maintaining blanching on these conditions, it thinks as follows. Green onions are inherently sticky and contain a mixture of polysaccharides such as cellulose, hemicellulose, protopectin and the like in the presence of water, but also contain fructose, glucose, sucrose, etc. (Agricultural Bunka Kyokai, Vegetable Gardening Encyclopedia 10, Rural Fishing Village Cultural Association, August 1989, p. 13), these mucilage materials are heated and eluted by high-temperature steam, and these on the inner surface of the core or spring ring It is presumed that it promotes binding. Moreover, in the case of hot water blanching, it is presumed that these sticky substances are eluted to the hot water side, so that it is difficult to bond the cores or the leek rings.

  In addition, as a steam warehouse, besides a batch-type steam warehouse, a continuous steam tunnel can also be used.

  Moreover, about the process after hold | maintaining for a fixed time in this steam store, it is preferable to cool the ring cut green on hold. As a cooling method, in addition to natural cooling, the air can be sent and cooled by a whirling machine or the like.

  Various means can be used for cooling. For example, in addition to natural cooling, it can also be carried out by a method of sending air by a whirling machine or the like, cooling it, and immersing it in water.

─The process of attaching sugars to the leek
In the present invention, the leek can be attached after the leek is held in the steamhouse and blanched. By passing through this step, breakage of the chopped green onion after freeze-drying can be further prevented, and the restorability and texture can be improved.

  As the sugar to be used, sugar alcohol such as sorbitol, dextrin and the like can be used in addition to glucose, maltose, lactose and the like. Moreover, it is preferable to use baking soda together in order to maintain the color of the cut green onion. These sugars can be added by a method such as immersion or spraying in a solution state, but can also be sprayed and mixed in a powder form. By these methods, sugar can be attached almost uniformly to the sliced green onion.

  The addition amount of the saccharide can be selected widely depending on the use, but can be added approximately 5% to 40% with respect to the weight of the leek.

--Freeze drying process--
Freeze-drying is carried out after holding in the vapor chamber or after adhering sugars. The lyophilization is performed under normal conditions, but the degree of vacuum is 0.8 Torr or less, the shelf temperature is 50 ° C. to 70 ° C., and the time is approximately 14 to 24 hours.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Example 1> Difference in effect of blanching with hot water or steam After washing about 4 kg of green onion (white onion: Senju green onion) with water, the root part of green onion and the tip of leaf blade part are removed, and a one-touch slicer By using a model OFS-62 (manufactured by Nakanishi Seisakusho Co., Ltd.), a round cut leek was produced by cutting into rounds at intervals of 12 mm. After further washing the cut green onion with water, divide it into approximately 300g portions, and blanching at 75 ° C, 80 ° C, 85 ° C, 90 ° C, 95 ° C and 98 ° C for 1 minute in hot water or in a steam chamber. Retained. The blanched green onion was freeze-dried for 16 hours at a shelf temperature of 60 ° C. under a vacuum of 0.1 Torr using a freeze dryer (model RO-100MB, manufactured by Kyowa Vacuum Technology Co., Ltd.).

The results are shown in Table 1. The evaluation is a five-stage evaluation, where the core portion and the leek ring are difficult to separate, “5” is the sample group without blanching, and the core portion and the leek ring that is most easily separated is “1”. And

As is clear from Table 1, in the case of blanching with steam, the separation of the core of the chopped green onion and the leeks was significantly inhibited.

<Example 2> Separation and color difference of green onion depending on temperature and holding time of steamhouse After washing about 18 kg of raw green onion (white onion: Senju green onion) with water, the root part of green onion and the tip of leaf blade part were removed. It was removed and cut into 12-mm intervals with a one-touch slicer (manufactured by Nakanishi Seisakusho Co., Ltd., model OFS-62) to produce a cut green onion. After further washing the cut green onion with water, it is divided into approximately 300 g portions and blanched at 70 ° C., 75 ° C., 80 ° C., 85 ° C., 90 ° C., 95 ° C. and 98 ° C. in the steam chamber. Hold for a certain time. Further, the chopped green onion after brunching was lyophilized with a freeze dryer (Kyowa Vacuum Technology Co., Ltd., model RO-100MB) under a vacuum of 0.1 Torr at a shelf temperature of 60 degrees for 16 hours.

  The results are shown in Table 2. The evaluation of ease of separation of the leek ring is a five-step evaluation, “5” is the sample section that is difficult to separate the core part and the leek ring. The easy thing is set to “1”.

In addition, the color is a five-level evaluation. If the leaf sheath part is normal, the white color of the leaf sheath part before branching is maintained as it is, and if the leaf sheath part is close to the leaf blade part, the green color is displayed. “5” was maintained vividly, and “1” was the most browned or green fading.

  As shown in Table 2, a good tendency was observed by keeping the color and the leek ring in a steam room at a temperature of 85 ° C. or higher for a certain time. As for the color, when it was kept at 75 ° C. or lower for a long time, it did not show a good color. On the other hand, discoloration was observed when stored at high temperature for a long time. Further, when the temperature of the onion ring was 80 ° C. or lower, no good thing was seen even when stored in the steam storage for a long time.

<Example 3> Separation and color difference of green onion when immersed in gelatin solution After washing about 4 kg of green onion (white onion: Senju green onion) with water, the root part of green onion and the tip of leaf blade part are removed. Then, with a one-touch slicer (manufactured by Nakanishi Seisakusho Co., Ltd., model OFS-62), it was cut into rounds at intervals of 12 mm to produce round cut green onions. After further washing the chopped green onion with water, the whole chopped green onion is immersed in a 1.0% gelatin solution (gelatin ES-290, Zerais Co., Ltd.), and is divided into approximately 300 g portions. It hold | maintained for 30 second in each temperature of 85 degreeC, 90 degreeC, 95 degreeC, and 98 degreeC in a vapor chamber. Further, the chopped green onion after brunching was lyophilized with a freeze dryer (Kyowa Vacuum Technology Co., Ltd., model RO-100MB) under a vacuum of 0.1 Torr at a shelf temperature of 60 degrees for 16 hours.

  The results are shown in Table 3. The evaluation of ease of separation of the leek ring is a five-step evaluation, “5” is the sample section that is difficult to separate the core part and the leek ring. The easy thing is set to “1”.

  In addition, the color is a five-level evaluation. If the leaf sheath part is normal, the white color of the leaf sheath part before branching is maintained as it is, and if the leaf sheath part is close to the leaf blade part, the green color is displayed. “5” was maintained vividly, and “1” was the most browned or green fading.

As shown in Table 3, when immersed in a gelatin solution, the separation of leek rings was remarkably improved according to each temperature condition. Further, the color of the onion did not change depending on whether gelatin was immersed or not.

  By using the present invention, it is possible to produce a freeze-dried leek that does not separate leek rings without causing discoloration or fading of the leek. The freeze-dried sliced green onion produced by the present invention can be usefully used as an ingredient for instant foods such as instant miso soup or instant noodles.

General green onion illustration. A figure of a green onion with a leaf sheath cut in a circle Figure showing the relationship between the temperature in the steamhouse and the holding time

Explanation of symbols

1 Leaf blade 2 Leaf sheath 3 Root 4 Leaf bud (core) in the center
5 Layered leaf buds (green onion)

Claims (3)

A method for producing a freeze-dried leek green onion comprising the following steps:
A) the step of washing the raw green onions,
B) A step of cutting the raw green onions into a round shape,
C) Step of immersing the cut surface of the cut green onion after cutting in a gelatin solution
D) A step of holding the cut green onion in a steam chamber at 85 ° C. to 100 ° C. for 15 seconds to 3 minutes and 45 seconds,
E) a step of freeze-drying the green onion held in the steam chamber,
A method for producing freeze-dried leek.
In the process D, the holding time for the round onion is 1 minute to 3 minutes 45 seconds at 85 ° C, 45 seconds to 2 minutes 30 seconds at 90 ° C, 30 seconds to 1 minute 45 seconds at 95 ° C, and 15 seconds to 1 at 98 ° C. 30 minutes
The method for producing a freeze-dried leek onion according to claim 1.
The manufacturing method of the freeze-dried leek onion of Claim 1 including the process which attaches saccharide | sugar to a lasso after the said D process and before the said E process.

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