JP4435135B2 - Method for producing freeze-dried tomatoes - Google Patents

Description

  The present invention relates to freeze-dried tomatoes used for processed foods such as instant foods, particularly instant noodles or ingredients for instant soup.

  In the freeze-drying method, drying progresses by sublimation of ice in the food, so there is no change in form due to drying, no extreme component changes occur during drying, and it can be dried while retaining color, taste, nutritional components, etc. There is a merit. Moreover, since it is made porous, it has the advantage of high resilience. Conventionally, various vegetable production methods using such a freeze-drying method have been disclosed.

  However, among vegetables, especially tomatoes may be damaged at the pretreatment stage such as blanching, and there are many voids in the state after freeze-drying, and the tissue after drying has a light impact. It is known that it is difficult to maintain the target shape due to damage (for example, see Patent Document 1).

In addition, in the experiments of the present inventors, when tomato is freeze-dried also in the experiments of the present inventors, the tomato after cutting is freeze-dried as it is, and the texture is not chewy. In many cases, the jelly-like substance leaked out after the hot water was lost.

In addition, when the tomato is cut into two vertically at the center and freeze-dried as it is, the jelly-like substance in the child chamber is ejected from the cut surface of the tomato during the freeze-drying. What was seen.

Therefore, the present inventor is a freeze-dried product of tomato that has a chewy texture and prevents the jelly-like substance from being lost after reconstitution, and in addition, when the tomato is cut vertically An object of the present invention is to provide a method for producing freeze-dried tomatoes which prevents the jelly-like substance from being ejected from the inside of the tomato cut surface.

  As a result of intensive studies to solve each of the problems described above, the present inventors firstly divided the tomato vertically in the center as a cutting method of tomato for improving the texture after lyophilization. The knowledge that it is effective was acquired. Moreover, it discovered that 2 divisions, 3 divisions, or 4 divisions were suitable as the number of divisions.

  Moreover, the knowledge that a texture improvement and prevention of the omission of a jelly-like substance can be realized by immersing this in a relatively concentrated sugar solution next was obtained.

  Furthermore, for the ejection of jelly-like substances from the inside of the tomato cut surface during freeze drying when tomato is cut vertically, the state of the tomato cut surface cut vertically before freeze drying is large from various experiments. It turns out that it is affecting.

  That is, when the tomato is cut horizontally, it is observed that the inside thereof is divided into a plurality of child chamber portions by the partition wall portion (2) as shown in FIG. For example, large tomatoes and medium-sized tomatoes are divided into 5 to 8 child chamber parts (3) as shown in FIG. 1, and mini tomatoes usually have two child room parts (3) as shown in FIG. It is divided into. On the other hand, when these tomatoes are cut vertically from the top of the core and divided into two, the cross sections as shown in FIGS. 3, 4, and 5 are seen. Of these, FIG. 3 shows that the left and right cut surfaces of the core portion (1) in the vertical cut surface are cut by the child chamber portion (3) and the jelly-like substance is exposed, and FIG. 4 shows the core portion (1 ), The partition wall portion (2) is overlapped on either the left or right side of the vertical cut surface, and the jelly-like substance (4) in the child chamber portion is hidden. FIG. 5 shows the core of the vertical cut surface. The left and right parts (1) overlap with the cutting of the partition wall part (2), and the jelly-like substance (4) is hidden over the entire vertical cut surface.

  In general, when a large number of tomatoes are cut vertically in the center, such as in two parts, divided tomatoes having the cross section shown in FIGS. 4 and 5 are produced in addition to those shown in FIG.

  And when it has a partition part (2) in at least one on the left and right of the core part (1) of the vertical cut surface as shown in FIG. 4 and FIG. It was found that a state in which a jelly-like substance was ejected from the inside of the surface (2) occurred. In order to prevent this ejection, a hole is made in the partition wall (2) of the cut surface, thereby opening the child chamber (3) containing the jelly-like substance (4) to the outside. It was found that the jelly-like material can be prevented from blowing out during freeze-drying.

Based on the above findings, the present invention has been completed and is a method for producing freeze-dried tomatoes, comprising the following steps:
A method for producing freeze-dried tomatoes comprising the following steps:
A) washing tomatoes,
B) A step of vertically cutting the tomato after washing into two, three or four divisions at the center,
C) drilling a hole in the partition wall of the cut surface of the tomato after cutting,
D) a step of immersing the tomato after the drilling in sugar;
E) a step of freeze-drying the tomatoes after the sugar immersion;
A method for producing freeze-dried tomatoes, characterized by comprising
It is.

  By forming a hole (7) in the partition wall (2) of the cut surface of the tomato as in the present invention, the jelly-like substance from the inside of the partition wall of the cut surface of the tomato during lyophilization is prevented from blowing out. Can do. Further, the sugar solution can be efficiently penetrated into the child chamber part (3) of the tomato through the hole (7) drilled in the subsequent sugar soaking process, and thus the lack of jelly-like substance after reconstitution with hot water. In addition, it is possible to increase the restoration effect of the crunchy texture.

Moreover, when adding the process of blanching processing to a tomato, if it processes in a hot hot water, the skin of a tomato will peel off and subsequent processing work will become difficult. As a result of examination of various conditions, the knowledge that the peeling of the tomato skin was prevented was obtained by adopting the condition that the tomato before being cut vertically was held for 10 to 60 seconds in hot water of 65 ° C to 85 ° C.
That is, the present invention further relates to a method for producing freeze-dried tomatoes according to paragraphs 0013, which includes steps A to E.
A step of holding the tomato after washing in hot water of 65 ° C. to 85 ° C. for 10 to 60 seconds after the A step and before the B step;
A method for producing freeze-dried tomatoes,
It is.

In addition, when improving the texture after restoration of freeze-dried tomatoes, how to keep the jelly-like substance filled in the child chamber part in a good yield and freeze-dry it in large quantities, and restore it well However, it was important to reproduce the tomato quality. The division of raw tomatoes has a problem of leaking out this jelly-like substance in the subsequent tomato processing step. In order to eliminate this problem, the knowledge that gelatin solution is attached after immersing sugar and before freeze-drying can further prevent the loss of jelly-like substances after restoration with hot water. It was.
That is, the present invention provides a method for producing a freeze-dried tomato according to paragraph 0013 or a method for producing a freeze-dried tomato according to paragraph 0015, and further after the step D and before the step E. A step of attaching a gelatin solution to
A method for producing freeze-dried tomatoes,
It is.

According to the method for producing a freeze-dried tomato according to the present invention, the mouthfeel is crunchy and prevents the jelly-like substance from being lost after reconstitution, and in addition, the jelly from the inside during freeze-drying The gaseous substance can be prevented from being ejected. Furthermore, when adding a blanching process, a jelly-like substance leaks out, and it can prevent the omission and peeling of the skin. The freeze-dried tomato produced by this method is excellent in texture and form and can be widely used for instant foods and the like.

Hereinafter, the manufacturing method of the tomato which concerns on this invention is demonstrated in detail.
1. The process of washing tomatoes The present invention uses tomatoes as raw materials, but as tomatoes of raw materials, large tomatoes such as “Momotaro” (variety name), medium-sized tomatoes such as “Fan Gogh” (variety name), It can be used for tomatoes of any size such as cherry tomatoes and cherry tomatoes. In particular, cherry tomatoes or cherry tomatoes are preferable from the viewpoint of shape retention after lyophilization.

  Washing is performed to remove foreign substances attached to the tomato. Various conventional methods can be used for washing the tomato, but it is carried out by washing with water before or after removing the tomato pieces. It is also possible to perform cleaning by putting it in a water tank or the like in a batch manner, or continuous cleaning by a machine.

  Moreover, when washing | cleaning, the process of sterilizing with disinfectants, such as sodium hypochlorite, can also be added. Various concentrations can be selected for the concentration of sodium hypochlorite, but it can be sterilized by using a material having a concentration of about 100 to 500 ppm so that all of the raw tomatoes are immersed. In the case of performing a sterilization process using a bactericide such as sodium hypochlorite, after that, after further washing with water, the subsequent process shifts.

2. Step of branching After the above water washing, a step of branching the raw tomato may be added. The blanching is performed to prevent discoloration or the like, to sterilize the surface bacteria, or to deactivate the enzyme. In the case of branching in the present invention, the tomato is not cut and kept in hot water at 65 ° C. to 85 ° C. for 10 to 60 seconds. If the tomato is cut and blanched with hot water, the jelly-like substance may leak and be lost, so at this stage, the raw tomato is not cut. In addition, when tomatoes are blanched for a long time with hot water, large tomatoes may peel off, and mini tomatoes may crack. These phenomena make subsequent processing operations difficult and degrade product quality and yield. Therefore, high-temperature and long-time blanching is not suitable. In the present invention, in consideration of the killing temperature of Escherichia coli or the like, the above disadvantage can be eliminated by performing hot water at about 65 ° C. to 85 ° C. for about 10 to 60 seconds.

  Furthermore, considering the speed of work and temperature adjustment of hot water, etc., 75 ° C. to 80 ° C., preferably about 20 seconds to 35 seconds. This blanching process can also employ blanching by steam.

3. Step of cutting tomato vertically Next, the tomato is cut and divided. In the case of dividing, there are a method of cutting horizontally and a method of cutting vertically, but in the present invention, it is cut vertically by including the core part in the cut surface in the vicinity of the center of the tomato, divided into 2, 3, or 4 To do. Further, the “longitudinal cut” in the present invention includes not only a case of cutting completely vertically but also a case of tilting slightly obliquely from the vertical.

  In order to divide the tomatoes, conventional vegetable cutting tools and machinery such as knives, cutters, and slicers can be used.

4). Step of drilling a hole in the partition wall of the cut surface of tomato Next, a step of drilling a hole (7) in the partition wall (2) of the cut surface after being vertically cut is performed. As for the cut surface of the tomato after being cut vertically, in the case of splitting the mini tomato, both the left and right cut surfaces of the core portion (1) in the vertical cut surface as shown in FIG. ) And the jelly-like substance (4) is exposed, and as shown in FIG. 4, the partition wall (2) is cut at either the left or right of the vertical cut surface with the core (1) as a boundary. Or the jelly-like substance (4) is hidden, or as shown in FIG. 5, the core (1) left and right of the vertical cut surface overlap with the cut of the partition wall (2), and the vertical cut surface The jelly-like substance (4) may be hidden on the entire surface.

  In the case of FIG. 4 or FIG. 5, the jelly-like substance (4) is ejected from the inside of the tomato at the time of freeze-drying, and this causes serious quality problems in the freeze-dried tomato as a product.

  Although it is not clear why the jelly-like substance (4) erupts when covered by the partition wall (2) at the vertical cut surface, the tomato jelly-like substance (4) may have a high sugar content, For this reason, the inside of the freeze-drying process is not completely frozen due to the freezing point depression, and when it is transferred to vacuum drying, the liquid part in the interior evaporates and foams, breaking the partition wall of the cut surface. It is estimated that the jelly-like substance spouts out.

  When the hole (7) is drilled in the partition wall of the cut surface, first, in the case of a cherry tomato having a child chamber divided into two, the partition wall (2) of FIGS. 4 and 5 It is only necessary to make a hole (7) only in the case, and it is not necessary to provide a hole when the jelly-like substance (4) is exposed as shown in FIG.

  However, in the actual manufacturing process, the presence / absence of the partition wall (2) is determined, and this determination is omitted in order to simplify and simplify the complexity of dividing the processing work and the complexity of the process. For all the tomatoes after cutting, holes may be provided uniformly on both the left and right sides with the core of the cut surface as a boundary. In the case of three divisions or four divisions, a hole is similarly formed in the partition wall of the cut surface.

  Next, as shown in FIG. 1, in the case of a large tomato or a medium tomato whose child chamber is divided into 5 to 8, even if the jelly portion is exposed on the cut surface, it is externally applied. Is not visually observed, but there may be a closed child chamber part inside. For this reason, regardless of whether the cut surface is a jelly part or a partition part, it is necessary to uniformly drill holes on both the left and right cut surfaces in the vertical direction with the core part as a boundary. Become. In this case, for example, by adjusting the direction of drilling as shown in FIG. 6, holes can be provided in all partition walls inside the tomato.

  When a hole is made in the cut surface, one or more holes may be formed on both the left and right sides of the core. Various methods that are commonly used can be used for drilling. For example, a needle, a comb, or the like can be used. The diameters of the needles and combs to be used should be of an appropriate diameter so that they can be dispersed and drilled at several locations corresponding to the area of the partition wall portion (2) of the tomato after cutting the raw material. However, those having a diameter of about 1 to 5 mm are preferable. Moreover, when making a hole, it is possible to pierce to reach the jelly-like substance, but it may penetrate to the pericarp.

  This drilling process promotes freezing of the jelly-like substance inside the tomato, and facilitates the vaporization of moisture and other liquid parts in the jelly-like substance, thus ensuring a gas outflow path to the outside. It is done.

  In the present invention, the case where the partition surface (2) is provided on the cut surface is not necessarily the case where the entire surface of the cut surface is completely covered by the partition wall portion (2), but the jelly portion is partially exposed. Even if it is a case, if almost the whole surface is covered with the partition wall, such a state is included.

5. Step of immersing tomato after drilling Next, the tomato after piercing is immersed in sugar. The sugar immersion is performed by immersing the divided tomatoes after puncturing in the sugar solution. Various known sugars can be used, for example, sugar, reduced syrup, etc. More specifically, for example, monosaccharides such as glucose, sorbitol, and xylose, and disaccharides such as fructose, maltose, and lactose. In addition, trisaccharides, tetrasaccharides, and polysaccharides can also be used, and a mixture thereof can also be used.

  Further, sodium chloride, amino acids such as glycine, alanine, glutamic acid and sodium glutamate or salts thereof may be added to these saccharides.

  The saccharide is an aqueous solution, and the concentration of the saccharide is approximately 20% by weight to 80% by weight including the additional salt described in paragraph No. 0034. In addition, in 20 weight% or less, it will be a little inferior in texture. Moreover, it is difficult to prepare a sugar solution of 80% by weight or more, and the influence on the taste becomes too strong, which is not suitable. Furthermore, when workability etc. are considered, the thing of 30 weight%-70 weight% is preferable. In addition, it is preferable that addition amount, such as salt other than sugar and an amino acid, shall be about 0 to 30 weight% with respect to the whole weight of a sugar liquid.

  Various times can be selected as the dipping time of the sugar dipping into the tomato after drilling, but considering workability and the like, about 10 minutes to 60 minutes is preferable.

6). Step of attaching gelatin solution After the above-mentioned sugar immersion, a step of attaching gelatin solution may be added. By adding this step, when freeze-dried tomatoes are reconstituted with hot water, it can be further prevented that the jelly-like substances are lost from the tomatoes, and the presence of jelly-like substances in the tomatoes after restoration with hot water A feeling can be strengthened. The concentration of the gelatin solution to be adhered can be widely used up to about 0.2 wt% to 10.0 wt%, but about 0.5 wt% to 5.0 wt% is particularly preferable.

  As a method for adhering tomatoes after sugar immersion to a gelatin solution, a conventionally known method can be appropriately employed. For example, a gelatin solution tank is provided, and a method of immersing the solution in a gelatin solution is sprayed. It is possible to use a method of attaching gelatin by, for example.

  The specific adhesion amount may be a short time in the case of immersion, and may be, for example, about 1 to 2 seconds or more. Further, in the case of attaching gelatin, the minimum effect can be obtained if it is attached not to the whole surface of the tomato but to the cut surface of the partition portion where the jelly-like substance exposed portion and the hole are formed.

7). Step of freeze-drying tomatoes After the above treatment, freeze-drying is performed by a conventional method. The freeze-drying conditions follow normal conditions, but the raw tomatoes are frozen, and then dried at a final shelf temperature of 50 ° C. to 70 ° C. for about 14 to 24 hours at a vacuum level of 0.8 Torr or less. .

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

<Example 1> Comparison of branching temperature and time of tomato After about 4.3 kg (about 300 pieces) of cherry tomato (carol seed) was washed with water, it was immersed in a solution of sodium hypochlorite 500 ppm for 5 minutes. Next, after washing again with water, it was divided into about 0.7 kg (about 50 pieces) and blanched in hot water at various temperatures for 20 seconds. In this case, cracking or peeling of the outer skin of tomato at each temperature was examined.

  As shown in Table 1, cracking of the outer skin occurred during blanching with hot water at 90 ° C. for about 20 seconds or more. Next, a comparison was made at a temperature of 85 ° C., changing the blanching time.

  As shown in Table 2, in the blanching at 85 ° C., cracking of the outer skin started to occur after 60 seconds or longer.

<Example 2> Effects of sugar soaking, gelatin adhesion, and drilling on cut surface About 3.6 kg (about 250) cherry tomatoes (carol seed) were washed with water, and then added to a solution of 500 ppm sodium hypochlorite. Immerse for a minute. Next, after washing again with water, it was immersed in hot water at a temperature of 80 ° C. for 20 seconds. Thereafter, the tomato pieces were removed, and a knife was placed vertically from the upper part of the core (one side of the piece) with a knife to divide it into two parts. The tomatoes after the division into two were divided into five test categories shown in Table 3 below, and processing corresponding to each test category was performed. One test category: about 3.5 kg (100 pieces (number of tomatoes after division)). In addition, about each test section, it adjusted so that the tomato in which the cut surface became a partition part was contained uniformly.

  As for the step of immersing the sugar, the tomato after being divided into two parts is immersed in a sugar solution consisting of 10% by weight of sodium chloride, 10% by weight of glucose and 50% by weight of reduced water candy: MU-45 (manufactured by Ueno Pharmaceutical) for 10 minutes went.

  Next, the step of immersing gelatin was performed by immersing in sugar and then immersing in a 2 wt% gelatin solution for 15 seconds before lyophilization.

  Furthermore, about the hole-drilling process to a cut surface, the diameter of a tomato after dividing into 2 parts is uniform including the cut surface (both sides of the left and right cut surfaces across the core) other than the one where the cut surface is a partition wall. A 2.5 mm skewer was used to pierce the tomato skin.

  The freeze-drying was performed by freeze-drying with a freeze dryer (Kyowa Vacuum Technology Co., Ltd., model RO-100MB) under a vacuum of 0.1 Torr and a shelf temperature of 60 degrees for 16 hours.

  Evaluations on texture, lack of jelly-like material, and ejection of jelly-like material on the cut surface are shown below. The evaluation was performed by five skilled panelists.

  First, regarding the texture, ten tomatoes after freeze-drying in which the jelly-like substance did not spout from the partition were collected, stored in a container, poured with 300 ml of hot water, and eaten after 3 minutes. The most excellent one was “5” and the worst one was “1”.

  Next, the lack of jelly-like substance after reconstitution with hot water was judged by whether or not the lack of jelly-like substance occurred when pouring hot water and holding it with chopsticks. At this time, the case where the lack of the jelly-like substance did not occur most was “5”, and the case where the lack of the jelly-like substance occurred most was “1”.

  The ejection of the jelly-like substance in the partition wall portion was evaluated at 100% of the number of jelly-like substances ejected in the total number after the lyophilization treatment.

  The results are shown in Table 4.

  As shown in Table 4, the texture was improved satisfactorily by sugar immersion. In addition, the texture was further improved by drilling.

  The lack of the jelly-like substance after reconstitution with hot water was improved only by soaking with sugar, but it could be further prevented by attaching a gelatin solution thereto.

  Regarding the ejection of the jelly-like substance in the partition wall, the ejection could be prevented very effectively by making a hole.

  By using the method of the present invention, it is possible to provide a freeze-dried tomato, which is a processed food of tomato, while maintaining a good texture without damaging its form. As a result, it is expected that tomatoes will be more useful for processed foods such as instant foods than ever.

Front view of cross section of large or medium tomato Front view of cross-section of cherry tomato Front view of cherry tomato vertical section (exposed jelly-like substance on both sides) Front view of vertical cut surface of cherry tomato (one side cut by partition) Front view of vertical cut surface of cherry tomato (both sides cut by partition) Cross section of large or medium-sized tomato and front view of drilling direction Cross section of cherry tomato

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core part 2 Partition part 3 Subchamber part 4 Jelly-like substance 5 Seed 6 Outer skin 7 Drilling (hole)
8 Drilling direction

Claims (3)

A method for producing freeze-dried tomatoes comprising the following steps:
A) washing tomatoes,
B) A step of vertically cutting the tomato after washing into two, three or four divisions at the center,
C) From the cut surface of the tomato after cutting, a step of drilling a hole in the partition wall so that there is no child chamber closed inside the tomato after splitting ,
D) a step of immersing the tomato after the drilling in sugar;
E) a step of freeze-drying the tomatoes after the sugar immersion;
The manufacturing method of the freeze-dried tomato characterized by comprising each process of these.
A step of holding the tomato after washing in hot water of 65 ° C. to 85 ° C. for 10 to 60 seconds after the A step and before the B step;
The manufacturing method of the freeze-dried tomato of Claim 1 which has this.
A step of attaching a gelatin solution to the sugar-immersed tomato after the step D and before the step E;
The manufacturing method of the freeze-dried tomato of Claim 1 or 2 which has these.

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