JP6694786B2 - DRY GREEN VEGETABLE FOR IMPROVED FOOD AND PROCESS FOR PRODUCING THE SAME - Google Patents

Description

  The present invention relates to a dried green vegetable for instant food and a method for producing the same.

  At present, as instant foods, a large number of products such as instant noodles, instant soups, instant miso soups, instant cooked rice, etc. that are easily eaten by boiling in water, cooking in a pot, cooking in a microwave oven, etc. are on the market.

  Ingredients for instant foods include dried meats, dried eggs, dried vegetables and the like. Of these, dried vegetables are generally blanched and then dried by a drying method such as ventilation drying, hot air drying, vacuum freeze drying, or microwave drying.

  Conventionally, green vegetables have a problem that their colors are discolored or discolored by enzymes or heating, and as a method for preventing discoloration or discoloration of green vegetables, it is common to carry out blanching treatment under alkaline conditions. However, when drying green vegetables, this alone is not sufficient to prevent fading or discoloration.

  As a method for producing a dried vegetable having good storability and quality, Patent Document 1 discloses that the vegetable has a pH of 7 to 10 and is blanched with an aqueous solution containing 0.01 to 20 g / L of magnesium ions and then dried. The method for producing dried vegetables is described. However, this method can retain the color tone of green vegetables after drying more than the blanching treatment under normal alkaline conditions, but in long-term storage, nitrogen treatment is performed using a highly airtight pouch. It is necessary to store it together with an oxygen scavenger, and when stored normally, there is a problem that the color changes immediately.

  Further, as a technique for maintaining the fresh color tone of green-yellow vegetables, Patent Document 2 discloses that blanched vegetables are adjusted to pH 8.0-9.0, immersed in a solution such as reduced starch syrup, and then freeze-dried. The technology is described. However, this method has a problem that the texture of the vegetables is significantly deteriorated depending on the type of vegetables because ice crystals generated during freezing destroy the texture of the vegetables due to the step of freezing. In addition, if a large amount of reduced starch syrup, etc., is added to vegetables, it will be over-foaming during drying and it will take time to freeze and dry, so it will be expensive to produce dried vegetables, and the amount of reduced starch syrup, etc. can be included. There was a limit.

JP 60-58033 A Japanese Patent No. 2926669

  An object of the present invention is to provide a dried green vegetable for instant foods and a method for producing the same, which can prevent fading or discoloration during storage.

  The inventor, as a result of diligent research on the cause of discoloration or discoloration during storage, it is not sufficient to control the pH of green vegetables during blanching, the free water of dried vegetables is reduced, and contact with oxygen occurs. I thought it was important to suppress Therefore, it was attempted not only to coat the vegetables with sugars but also to suppress free water in the dried vegetables by adding sugars to the green vegetables whose pH was controlled by blanching. However, depending on the type of saccharides used, it was found that rather than suppressing discoloration during storage, it promotes discoloration, and as a result of further diligent research, it was found that the type and content of saccharides to be added are important. Came to.

That is, it is a dry green vegetable for instant food, contains 10% by weight or more of maltose and / or lactose, has a water content of 14% by weight or less, and has a total sugar content of 55 to 80% by weight. And a blanching step of blanching the dried green vegetable for instant food, characterized in that the pH of a 20-fold diluted liquid of the dried green vegetable is 7-8.
At least lactose to the green vegetables blanched in the blanching step, a saccharide addition step of adding one or more saccharides selected from maltose and malt syrup, and the green vegetable added saccharides in the saccharide addition step. A hot-air drying step of drying with hot air of 100 ° C. or lower, which is a method for producing a dried green vegetable for an instant food, wherein the dried green vegetable for an instant food obtained by the production method is maltose and / or lactose. Is 10% by weight or more, the water content is 14% by weight or less, the total sugar content is 55-80% by weight, and the pH of the 20-fold diluted liquid of the dried green vegetables for instant food is 7-8. A method for producing a dried green vegetable for an instant food, which is characterized in that

  Further, in the saccharide addition step, it is preferable that the magnesium salt is added by adding a magnesium salt to improve the green color development immediately after drying.

  Furthermore, it is preferable to adjust the pH of a 20-fold diluted liquid of dried green vegetables to 7.2 to 7.8.

  INDUSTRIAL APPLICABILITY The present invention can provide a dried green vegetable for instant foods, which can prevent discoloration or discoloration during storage, and a method for producing the same.

  Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the following description.

  The green vegetables in the present invention are vegetables showing green color derived from chlorophyll, and include, for example, spinach, komatsuna, cabbage, broccoli, peppers, bitter melon, leek, leek, scallions, green beans, peas, radish radish and bean seedlings. .

  If necessary, green vegetables are washed and sterilized with hypochlorous acid, and then cut into appropriate sizes. The cut green vegetables may be immersed in lime water or an aqueous solution containing bittern.

  Then, blanching the cut green vegetables. When green vegetables are dried as they are, chlorophyll is decomposed into pheophytin and fades. Therefore, it is common to carry out blanching. The blanching method is not particularly limited, and the time may be adjusted by boiling or steam according to the green vegetables to be used.

  When blanching by boiling, the pH of the blanching solution is not particularly limited, but chlorophyll is decomposed when it becomes acidic, and when the alkalinity is too strong, the fibers of green vegetables become soft and the texture becomes too soft. Therefore, it is preferably neutral to weakly alkaline, and it is preferable to carry out branching while adjusting the pH to about 7 to 8.5 with carbonate or the like.

  Next, the blanched green vegetables are dehydrated if necessary, and sugar is added. The purpose of adding saccharides is to coat dry green vegetables to block oxygen and reduce free water to prevent fading and discoloration during storage, as well as to give vegetables flexibility during drying, This is to prevent damage to the vegetables inside and to prevent damage during transportation by hardening after drying and ensuring resilience when used as an ingredient for instant food.

  Usually, it is said that saccharides react with free amino acids to cause a Maillard reaction and turn brown. It is said that this reaction is more likely to occur in a saccharide having a reducing property, and it was considered that the use of a reducing saccharide causes a Maillard reaction during storage and discoloration (browning) during storage. Therefore, we thought that discoloration during storage could be suppressed by using sucrose, trehalose, reduced starch syrup, etc. that do not show reducibility, but unexpectedly even when using sugars that do not show reducibility It was found that the discoloration of No. 1 proceeded and that the Maillard reaction was not necessarily the cause of the discoloration during storage. Therefore, as a result of verification using various sugars, although the cause is unknown, it was found that lactose and maltose are preferable for suppressing discoloration during storage, in order to suppress discoloration during storage.

  The sugar added in the present invention is at least one or two or more kinds selected from malt syrup containing a large amount of lactose, maltose and maltose, and as the lactose or / and maltose content in the dried green vegetables, in the dried green vegetables. It is preferable to add 10 wt% or more, more preferably 22 wt% or more. The lactose and maltose contents may be measured by the HPLC method. The malt syrup according to the present invention is a product obtained by decomposing starch with an acid or an enzyme, and does not include reduced syrup obtained by reducing this with hydrogen. The lactose and / or maltose content after drying is as high as possible, but as described below, the total sugar content in the dried green vegetables is more than 80% by weight based on the weight of the dried green vegetables. Since it is substantially difficult to do so, it is at most 80% by weight in the dry green vegetables, and is 70% by weight or less in consideration of the original sugar amount of the vegetables.

  Moreover, it is preferable that the total amount of sugar in the dried green vegetables is added so as to be 55 to 80% by weight based on the weight of the dried green vegetables. As for the method for analyzing the total sugar amount, when only monosaccharides, disaccharides and reducing sugars thereof are added, the respective sugars may be analyzed by the HPLC method and integrated to calculate. When the added sugar contains sugars of three or more sugars such as maltose starch syrup and reduced starch syrup, it may be calculated by the phenol-sulfuric acid method. When the total amount of sugar in the dried green vegetable is less than 55% by weight based on the weight of the dried green vegetable, the coating of the dried green vegetable with the saccharide becomes incomplete, and fading or discoloration easily occurs. Further, the green vegetable lacks flexibility during drying, becomes liable to crack during production, becomes brittle after drying, and becomes liable to crack during transportation, and also has poor restorability. On the contrary, setting the total sugar content in the dried green vegetables to more than 80% by weight based on the weight of the dried green vegetables is a reality because the original solid content of the vegetables and the water content of the dried green vegetables are present. Is difficult. A more preferable range is 65 to 75% by weight.

  As the sugars to be added in the present invention, in addition to lactose, maltose and malt starch syrup, glucose, trehalose, reducing sugars such as sorbitol, reducing starch syrup, starch degradation products, and reduced starch degradation products can be mixed. It is preferable to add lactose and / or maltose as much as possible as the sugar to be added.

  In addition, examples of sugars that promote discoloration during storage include fructose and sucrose. Therefore, as sugars to be added, it is preferable not to include fructose and sucrose as much as possible, but fructose and sucrose are often originally contained in green vegetables, and the fructose content in the dried green vegetables is 10% by weight. % Or less, more preferably 5% by weight or less. The fructose and sucrose content may be analyzed by the HPLC method.

  As a method for adding saccharides, the saccharides may be added by powder mixing or may be added by immersing in a saccharide aqueous solution.

  Further, it is preferable to add a magnesium salt such as magnesium carbonate or magnesium chloride at the same time when adding the saccharide. By adding the magnesium salt, the green state after drying is easily maintained as compared with the case where the magnesium salt is not added. In addition, the pH of the dried green vegetables can be adjusted to fall within a predetermined range by adding an alkaline agent such as sodium carbonate or lime water when adding the saccharides.

  Next, the green vegetables to which sugars have been added are dried so that the water content is 14% by weight or less. The drying method is not particularly limited, but ventilation drying or hot air drying is preferable in order to add a large amount of sugar and to dry at low cost. When hot-air drying is performed, if the temperature is higher than 100 ° C., discoloration proceeds during drying, which is not preferable. It is more preferable to dry at 80 ° C. or lower, and further preferably at 60 ° C. or lower. The water content of the dried green vegetables is preferably as low as possible, more preferably 10% by weight or less, and further preferably 7% by weight or less. The water content may be measured under atmospheric drying method at 105 ° C. for 4 hours.

  Further, the pH of the dried green vegetables is preferably 7 to 8 in the 20-fold diluted liquid of the dried green vegetables. As an example of the analysis method, 190 g of pure water is added to 10 g of dried green vegetables, the mixture is crushed and stirred by a mixer, and the pulverized and stirred 20-fold diluted solution may be measured with a pH meter (electrode type). When the pH is less than 7, fading of the green color is observed in the stage after drying, and when the pH is higher than 8, discoloration easily proceeds during storage. More preferably, the pH is adjusted at the time of blanching or addition of saccharides so that the pH of the 20-fold diluted liquid of dried green vegetables is in the range of 7.2 to 7.8.

  Dried green vegetables for instant foods are used as ingredients for instant foods after being reconstituted by boiling in water, cooking with a pot, microwave cooking, and the like.

The present embodiment will be described in more detail below with reference to examples.
<Preliminary test>
It was verified in a preliminary test how different kinds of sugars affect fading or discoloration during storage. As the types of sugars, glucose, fructose, lactose, maltose, sucrose, trehalose, sorbitol, malt starch syrup (maltose content 33%, solid content 75%), and reduced starch syrup (solid content 75%) were used.

  As the dried green vegetables, cabbage dried with hot air was used as an index.

  As a method for producing the dried cabbage, the outer cabbage leaf having a green color is cut into a size of about 30 × 25 mm, blanched with a 0.1% sodium bicarbonate solution at 98 ° C. for 2 minutes, and the blanched cabbage is taken out. After cooling and washing with running water, centrifugal dehydration was performed until the weight of the raw cabbage was 60% by weight. Then, 20% by weight of the above-mentioned saccharides as a solid content is added to 100% by weight of the dehydrated cabbage, and the mixture is left to mix and stand so that the weight of all the saccharides contained in the dried cabbage is about 70% by weight. After removing excess drip, it is dried at 80 ° C for 2 hours, further dried at 70 ° C for 2 hours, and dried at 60 ° C for 4 to 6 hours to adjust the water content to 7% by weight. Then, a dried cabbage sample was prepared. Further, the pH of the 20-fold diluted solution of the dried cabbage sample was adjusted to be about 7.5.

  As a method for easily confirming the change in color tone of the prepared dried cabbage sample during storage, moisturize 10% by weight of water to the dried cabbage, and heat the moistened dried cabbage at 60 ° C for 48 hours to force it. And the color tone was evaluated. The evaluation was conducted visually by five skilled panelists, and when the color tone after drying was set to 5, the appearance was equivalent to 5 points, and the color tone which was slightly discolored or discolored was 4 points. 3 points were those that had fading or browning but were generally acceptable, 2 points were those that were not noticeable as fading or browning, and 2 points were those that were markedly fading or discoloring and were extremely impractical as a product.

  The preliminary test results are shown in Table 1 below.

  From the above results, it was found that lactose, maltose, and malt syrup containing a large amount of maltose are preferable as the saccharides having an effect of preventing discoloration or discoloration during storage. On the contrary, it was found that fructose and sucrose are likely to promote discoloration during storage. Regarding other sugars, discoloration progresses to some extent during storage, but the degree of discoloration is less than that of fructose and sucrose. From the results of malt syrup (solid content 75%, sugar composition maltose 33% by weight), lactose and If maltose is contained in a large amount, it is considered that the influence on fading or discoloration during storage is small even if some sugars are contained. In addition, sucrose, trehalose, sorbitol and reduced starch syrup which do not show reducibility may show discoloration during storage, suggesting that the Maillard reaction is not the only cause of discoloration during storage.

<Experiment 1> Regarding sugar content and lactose or / and maltose content (Example 1-1)
The addition of saccharides was 4% by weight of maltose and 6% by weight of glucose relative to 100% by weight of dehydrated cabbage, and after sufficient mixing of the saccharides, the mixture was allowed to stand at 25 ° C. for 1 hour to infiltrate, and then dried according to the method of the preliminary test. A cabbage sample was prepared.

(Example 1-2)
The addition of saccharides was made to be 8% by weight of maltose and 12% by weight of glucose with respect to 100% by weight of dehydrated cabbage, and after sufficiently mixing the saccharides, the mixture was allowed to stand at 25 ° C. for 1 hour to allow it to permeate and then dried according to the method of the preliminary test. A cabbage sample was prepared.

(Example 1-3)
A dried cabbage sample was prepared according to the method of the preliminary test except that the saccharide was added to 20% by weight of maltose relative to 100% by weight of the cabbage and the saccharide was sufficiently mixed and then allowed to stand by allowing it to stand at 25 ° C. for 1 hour.

(Example 1-4)
Dried cabbage sample was prepared according to the method of the preliminary test except that the saccharides were added to 4% by weight of lactose and 6% by weight of glucose with respect to 100% by weight of cabbage, and the saccharides were thoroughly mixed and then allowed to stand by allowing to stand at 25 ° C. for 1 hour. Was produced.

(Example 1-5)
Dried cabbage sample was prepared according to the method of the preliminary test except that the addition of saccharides was 8% by weight of lactose and 12% by weight of glucose with respect to 100% by weight of cabbage, and the saccharides were thoroughly mixed and allowed to stand by allowing to stand at 25 ° C. for 1 hour. Was produced.

(Example 1-6)
A dry cabbage sample was prepared according to the method of a preliminary test except that lactose was 20% by weight with respect to 100% by weight of cabbage, and the saccharide was thoroughly mixed and then allowed to stand by allowing it to stand at 25 ° C. for 1 hour.

(Example 1-7)
Lactose was 4% by weight, maltose was 4% by weight and glucose was 12% by weight with respect to 100% by weight of cabbage, and after sufficient mixing of the saccharides, the mixture was allowed to stand at 25 ° C. for 1 hour for permeation, and a preliminary test was conducted. Dry cabbage samples were prepared according to the method.

(Example 1-8)
According to the method of the preliminary test, except that the sugar addition was 30% by weight of malt starch syrup (maltose content 33% by weight) with respect to 100% by weight of cabbage, and the sugars were thoroughly mixed and allowed to stand by allowing to stand at 25 ° C. for 1 hour. A dried cabbage sample was prepared.

(Comparative Example 1-1)
A dried cabbage sample was prepared according to the method of the preliminary test except that the sugars were added to maltose 3% by weight and glucose 7% by weight with respect to 100% by weight of cabbage, and the sugars were thoroughly mixed and allowed to stand by allowing to stand at 25 ° C. for 1 hour. It was made.

(Comparative Example 1-2)
A dried cabbage sample was prepared according to the method of the preliminary test except that the sugar was added to 4% by weight of maltose and 4% by weight of glucose with respect to 100% by weight of cabbage, and the saccharide was thoroughly mixed and then allowed to stand by allowing it to stand at 25 ° C. for 1 hour. It was made.

(Comparative Example 1-3)
Lactose was 3% by weight and glucose was 7% by weight with respect to 100% by weight of the cabbage, and the dried cabbage sample was prepared according to the method of the preliminary test except that the saccharides were thoroughly mixed and then allowed to stand at 25 ° C. for 1 hour for permeation. It was made.

  The total sugar content and sugar content of each dried cabbage sample were analyzed. In addition, since the sugars to be added are disaccharides or less except for Examples 1-8, each sugar was individually analyzed by the HPLC method and then integrated to calculate the total sugar amount. For Examples 1-8, the maltose content was measured by the HPLC method and the total sugar amount was measured by the phenol-sulfuric acid method. Further, in addition to the appearance evaluation in the deterioration test conducted in the preliminary test, the breakage resistance of the cabbage during and after drying was also evaluated. It has excellent flexibility during drying, hardness after drying, strength, and is very good to be broken and very good ◎, flexibility during drying, hardness after drying, and strength are also good, and it is generally good for breaking. ○: softness during drying, hardness after drying, lack of strength and fragility, △: softness during drying, hardness after drying, significantly lack of strength, markedly fragility, x did. The results are shown in Table 2.

  Regarding the fragility, it can be seen that when the total sugar amount is 55% by weight or more, the higher the total sugar amount, the better, and particularly when the total sugar amount is 65% by weight or more, it is found that it is very good. It is also found that when the total sugar amount is less than 55% by weight, not only is it easily broken, but also discoloration is likely to occur even when maltose is included. It was shown that discoloration during storage was suppressed when the maltose or / and lactose content was 10% by weight or more and the total sugar amount was 55% by weight or more.

  In addition, maltose can suppress the change in color tone during storage more than lactose, but sugar is sticky and the stickiness of sugar is pushed by adding lactose. Improves aptitude. Since lactose has a unique sweetness, it is preferable to add lactose mainly to maltose in order to improve the production suitability.

<Experiment 2> Regarding pH adjustment and addition of magnesium salt (Example 2-1)
Dry cabbage samples were produced according to the method of Example 1-7, except that hot water at 98 ° C. was blanched for 2 minutes, and the pH of the dried cabbage sample after drying was adjusted to 7.0.

(Example 2-2)
Dry cabbage sample was prepared according to the method of Example 1-7, except that the 20-fold diluted solution of the dried cabbage sample after drying was subjected to blanching treatment with a 0.05% aqueous sodium hydrogen carbonate solution at 98 ° C for 2 minutes. Was manufactured.

(Example 2-3)
Dry cabbage sample was prepared according to the method of Example 1-7, except that the cabbage was treated with 0.15% sodium bicarbonate aqueous solution for 2 minutes at 98 ° C., and the pH of the dried cabbage sample after drying was adjusted to 7.8. Was manufactured.

(Example 2-4)
Dry cabbage sample was prepared according to the method of Example 1-7, except that the cabbage was blanched with a 0.30% aqueous sodium bicarbonate solution at 98 ° C for 2 minutes and the pH of the dried cabbage sample after drying was adjusted to 8.0. Was manufactured.

(Example 2-5)
Example 1-except that the magnesium carbonate salt was added in an amount of 0.1% by weight to the weight of the cabbage after dehydration when the sugar was added, and the pH of the 20-fold diluted solution of the dried cabbage sample after drying was 7.7. A dried cabbage sample was prepared according to the method of 7.

(Example 2-6)
After blanching in hot water at 98 ° C for 2 minutes, adding 0.1% by weight of magnesium carbonate salt to the weight of the dehydrated cabbage at the time of adding sugar, and adding 0.1% by weight of sodium carbonate to dry. A dried cabbage sample was produced according to the method of Example 1-7, except that the pH of the 20-fold diluted solution of the dried cabbage sample of was set to 7.5.

(Comparative Example 2-1)
Dry cabbage was prepared according to the method of Example 1-7 except that the 20-fold diluted solution of the dried cabbage sample was subjected to blanching treatment with a 0.05% aqueous solution of citric acid for 2 minutes at 98 ° C. and the pH of the diluted cabbage sample was 6.5. A sample was manufactured.

(Comparative Example 2-2)
Dry cabbage sample was prepared according to the method of Example 1-7 except that a 20-fold diluted solution of the dried cabbage sample after drying was subjected to a blanching treatment with a 0.50% aqueous sodium hydrogen carbonate solution at 98 ° C for 2 minutes. Was manufactured.

  Also, in Experiment 2, the appearance evaluation of the deterioration test performed in the preliminary test was similarly performed. The results are shown in Table 3.

  Although the discoloration at the time of blanching can be suppressed by adjusting the pH to the alkaline side at the time of blanching, if the pH of 20 times diluted after drying is made higher than 8, the discoloration at the time of forced deterioration proceeds. Conversely, if the pH is adjusted to an acidic side during blanching and the pH of 20-fold dilution after drying is less than 7, fading proceeds during blanching and during drying. Therefore, it is preferable to adjust the pH during the blanching treatment or the addition of saccharides so that the 20-fold diluted pH after drying becomes 7 to 8, more preferably 7.2 to 7.8.

  Further, by adding a magnesium salt at the time of adding sugar after blanching and adjusting the pH as necessary, the green color tone after drying becomes more vivid and the color tone is maintained even after forced deterioration.

Claims (6)

A dry green vegetable for instant food that has been dried with hot air ,
Containing 10% by weight or more of maltose and / or lactose,
Has a water content of 14% by weight or less,
A total sugar content of 6 5-80 wt%,
The dried green vegetable for instant food is characterized in that a 20-fold dilution of the dried green vegetable for instant food has a pH of 7-8. The dried green vegetable for instant food according to claim 1, wherein the content of maltose and / or lactose is 22% by weight or more. The dried green vegetable for instant foods according to claim 1 or 2, wherein the dried green vegetable for instant foods contains magnesium salt. The dry green vegetable for instant foods according to any one of claims 1 to 3, wherein the 20-fold diluted solution of the dry green vegetable for instant foods has a pH of 7.2 to 7.8. A blanching process for blanching green vegetables,
At least lactose to the green vegetables blanched in the blanching step, a saccharide addition step of adding a saccharide containing one or more selected from maltose and malt syrup,
A method for producing a dried green vegetable for instant food, comprising a hot air drying step of drying the green vegetable to which sugar has been added in the sugar adding step with hot air of 100 ° C. or lower,
In the blanching step or the saccharide addition step, the pH of the 20-fold diluted solution of the dried green vegetables for instant foods after production is adjusted to 7-8.
In the saccharide addition step, maltose and / or lactose is contained in the dry green vegetable for instant food in an amount of 10 wt% or more, and the saccharide is added so that the total sugar content is 65 to 80 wt%,
In the drying step, the method for producing a dried green vegetable for an instant food is characterized in that the dried green vegetable for an instant food has a water content of 14% by weight or less. The method for producing a dried green vegetable for instant food according to claim 5 , wherein magnesium salt is added in the sugar addition step.