JP2011239761A - Method for preventing heat discoloration of green plant and retort food non-discolored by heat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide retort food and beverage capable of safely preserving green color of green vegetables and the like with completely rejecting the use of colorant and preservative which are undesirable for health.SOLUTION: Aqueous solution in which minute amounts of organic acid and zinc ions are put is prepared using a copper container, a green plant is put therein, and the green plant in the aqueous solution is heat-treated at 60°C or more to prevent the heat discoloration of the green color. When antioxidant is added to the green plant processed by the heat-discoloration preventing method, the retort food and beverage can acquire a property which causes no heat discoloration and preserves the green color even being sterilized by heat of 121°C or more.

Description

  The present invention relates to a method for preventing green fading due to heating of a green plant and a food that prevents green fading due to thermal discoloration.

Conventionally, many methods for preventing or fading the green color of vegetables and seaweeds containing chlorophyll have been proposed. However, in actuality, prevention of fading by heating vegetables and beverages has not been put into practical use other than a method using a colorant.
For example, since green tea in a plastic bottle fades and turns brown during heat sterilization, there is no beverage tea in a plastic bottle that is green in nature. Moreover, since the retort food heat-sterilized at 121 degreeC discolors a green vegetable by heating, the retort food holding green without using a coloring agent is not found.

  For this reason, as a method for dealing with the deterioration or fading of green color, a method of coloring green vegetables or seaweed in an aqueous solution containing copper chlorophyll or copper chlorophyllin alkali metal salt and a reducing agent (Patent Document 1) or metal ions. There has been proposed a method of recovering the green color of a plant by bringing it into contact with the contained yeast liquid, or keeping it green (Patent Document 2).

  However, the method described in Patent Document 1 uses copper chlorophyll, which is a colorant for food additives, and can be used only for some foods.

  On the other hand, since the method disclosed in Patent Document 2 uses a metal ion-containing yeast, as a method of restoring the green color of a browned plant because the yeast odor adheres to food or the yeast has less metal ions, etc. Seems to be effective, but it is difficult to prevent green fading by heat treatment.

JP-A-6-217732 JP 2004-67546 A

  As described in Patent Documents 1 and 2, it is possible to maintain the green color of retort foods using green vegetables and to maintain a green color without using a colorant or adding an unfavorable amount of copper to health. It aims to be able to provide.

  In order to achieve the above-mentioned object, the present inventor has conducted intensive research and puts an aqueous solution containing a small amount of organic acid into a copper container and heats it for a required time without adding an unfavorable amount of copper for health. Elution of copper ions to the extent that there are no health problems, mixing green plants and zinc ions in them, and heat-treating them at a temperature of 60 ° C or higher effectively prevents the fading of green plants I found out that I can do it.

  That is, according to the method of claim 1 of the present invention, an aqueous solution containing a trace amount of an organic acid is put in a copper container and heated for a required time, and then the green plant and zinc ions are mixed in the aqueous solution of the copper container, and the temperature is 60 ° C. or higher. The heat discoloration of the green plant can be prevented by heat treatment with.

  Claim 2 can be processed by the method of claim 1 to obtain a retort food having a green color that does not discolor heat.

  Further, according to claim 3, in the method for preventing thermal discoloration of a green plant, by adding an antioxidant to the green plant simultaneously with the heat treatment or after the heat treatment, oxidation due to heat during the heat sterilization treatment is suppressed. It can prevent heat discoloration of green plants and can make retort food that does not discolor heat.

According to the present invention, the following effects can be exhibited.
By putting a small amount of an organic acid aqueous solution in a copper container and heating it, copper ions having a degree that does not affect the human body can be freely controlled and eluted.

  By facilitating heating in the presence of a small amount of copper ions and zinc ions, green fading of green plants can be prevented.

  By adding an antioxidant during cooking and heat sterilization, oxidation due to heat is suppressed, and green fading of a green plant can be prevented.

(1) Organic acid An organic acid is used in the present invention to promote elution of copper ions from a copper container.
Organic acids include citric acid, acetic acid, malic acid, gluconic acid and the like, but citric acid and sodium citrate are preferably used.

  For example, when 2000 cc of water and 1 g of citric acid were added to a copper pan and heated for 15 minutes, the copper ion concentration of the aqueous solution became 7 ppm. However, the copper ion concentration when only 2000 cc of water is put in a copper pan and heated for boiling for 15 minutes is 1 ppm or less. By changing the amount of citric acid added, the time and temperature for heating and boiling, the copper ion concentration can be changed. Can be adjusted freely.

(2) Zinc ion Any zinc ion may be used as long as it is ionized, such as zinc gluconate, zinc-containing yeast, and zinc-containing lactic acid bacteria. In particular, it is preferable to use a highly safe, tasteless and odorless zinc-containing lactic acid bacterium for food.

(3) Antioxidants Antioxidants stipulated by the Food Sanitation Law as food additives include ascorbic acid, sodium ascorbate, and erythorbic acid, but sodium ascorbate is used from the point of taste. preferable.
Moreover, it is preferable that the addition amount of sodium ascorbate shall be 0.1% or less with respect to a green plant.

(4) Green plants The green plants to which the present invention is applied are typically green vegetables and tea leaves, but any food or food material containing chlorophyll such as seaweeds or fruits will be targeted.

  In addition, the green vegetables used in the present invention may be whole vegetables or a part thereof or processed products, and vegetables that have lost the green color due to miso pickling or salting, etc., and browned into vegetables are also targeted. is there.

(5) Method for preventing thermal discoloration The green plant according to the present invention prevents green fading by substituting copper and zinc for magnesium contained in chlorophyll.
Copper and zinc are both minerals necessary for the human body, but copper is not preferable for health if the intake is too much. Therefore, in the present invention, copper ions within an allowable range are eluted from a copper container and used without adding copper.
The zinc ion content is preferably 10 ppm to 1000 ppm, and the zinc content in this range is safe and useful for the human body.

In order to replace the magnesium contained in chlorophyll with copper and zinc, the higher the treatment temperature, the faster the replacement rate. However, since the flavor and components of the vegetables are impaired when the temperature becomes high, the processing temperature is preferably 60 to 100 ° C.
In addition, the process of adding an organic acid and zinc ion is not restricted to the above-mentioned process, It can also heat simultaneously with water.

(6) Retort food not thermally discolored Green plants treated by the method for preventing heat discoloration according to the present invention often require heat sterilization in order to enable subsequent distribution processes and long-term storage. The retort food to which the present invention is applied is not limited to a retort food that is normally sterilized at 121 ° C. or higher, but is also a food that is heat sterilized at 80 ° C. or higher. Moreover, the retort food which does not carry out heat discoloration not only about green but another hue is also contained.

  Examples of the present invention will be specifically described below.

Greenpeace Put 2000cc of water and 1.5g of citric acid in a copper pan and boil for 15 minutes. Thereafter, 1.5 g of zinc-containing lactic acid bacteria (containing 10% Zn) and 100 g of green peas were added and heated at 95 ° C. for 20 minutes.
The aqueous solution at this time had a copper ion concentration of 8 ppm and a zinc ion concentration of 60 ppm.
Thereafter, 1 g of sodium ascorbate was added and heated for 10 minutes. The green peas, which were greenish yellow at first, turned beautiful green, so they were removed from the copper pan, washed with water, and sealed in a retort pouch. Next, the above green pea pouch was sterilized by heating at 121 ° C. for 20 minutes. The green color of green peas after sterilization was almost the same as before sterilization, and the green color was maintained, and no discoloration was observed after storage at room temperature for about 3 months.

As a comparative example, the same treatment as above was performed using a stainless steel pan instead of a copper pan.
The aqueous solution at this time had a copper ion concentration of 0 ppm and a zinc ion concentration of 60 ppm.
The green peas turned green yellow to yellow, and the green faded.

Spinach Put 2000 cc of water and 1 g of citric acid in a copper pan and boil for 15 minutes. Thereafter, 1 g of zinc-containing lactic acid bacteria (containing 10% Zn) and 100 g of spinach were added and heated at 95 ° C. for 20 minutes.
Since the spinach became a beautiful blue-green color, it was taken out from the copper pan, washed with water, added with 1 g of sodium ascorbate, put into a mixer and pulverized into a paste. The spinach paste was sealed in a retort pouch and sterilized by heating at 121 ° C. for 20 minutes.
The blue-green color of spinach paste was almost the same before and after heat sterilization, and there was no color change.

As a comparative example, the same treatment was performed without using citric acid.
The spinach became slightly lighter green than the above, but the green color before and after heat sterilization was almost the same, and no green discoloration was seen.

Matcha In a copper pan, add 2000 cc of water, 2 g of citric acid, and 2 g of zinc-containing lactic acid bacteria (containing 10% Zn) and boil for 15 minutes. Thereafter, 50 g of matcha was added and heated at 95 ° C. for 30 minutes with stirring. Since the aqueous solution became a beautiful green juice, 1 g of sodium ascorbate was added and sealed in a PET bottle. The matcha green juice in a plastic bottle was sterilized by heating at 121 ° C. for 20 minutes, but there was no discoloration of green.

As a comparative example, the same treatment as above was performed without using sodium ascorbate.
Before the heat sterilization, it became a beautiful green matcha green juice, but after the heat sterilization, the green color changed to brownish yellow.

Salted cherry leaves Put 2000cc of water, 1g of citric acid and 1g of zinc-containing lactic acid bacteria (containing 10% Zn) in a copper pan and boil for 15 minutes. Then, 50 g of salted cherry leaves that turned brown were added and heated at 95 ° C. for 15 minutes. Since the cherry leaves became a beautiful blue-green color, they were removed from the copper pan, washed with water, sealed in a retort pouch and sterilized by heating at 121 ° C. for 20 minutes.
The cherry leaves retained the same color as before heat sterilization, and there was no fading due to heating.

According to the present invention, it is possible to provide a retort food that retains a green color.
The usage form may be a product sealed in a pouch or tray container, a beverage product sealed in a can or a plastic bottle, and the like. Moreover, it becomes possible to develop a new processed food having a green color by adding it to a food product that wants to maintain a green color in a paste or powder state.

Claims (3)

An aqueous solution containing a trace amount of an organic acid is placed in a copper container and heated for a predetermined time, and then green plant and zinc ions are mixed in the aqueous solution of the copper container and heated at 60 ° C. or higher. A method for preventing thermal discoloration of plants. An aqueous solution containing a trace amount of an organic acid is placed in a copper container, heated for a predetermined time, and then mixed with an aqueous solution of the green plant and zinc ions in the aqueous solution of the copper container, and heat-treated at 60 ° C. or higher for retort food that does not discolor. In the method for preventing thermal discoloration of green plants, an antioxidant is added to the green plant simultaneously with heat treatment or after heat treatment, and the method for preventing heat discoloration of green plants according to claim 1 and 2, Retort food that does not discolor heat.