JP7108316B2 - Method for producing high-folate leafy vegetables - Google Patents

Description

TECHNICAL FIELD The present invention relates to high folic acid leafy vegetables and methods for producing the same.

Folic acid is a type of vitamin B, also called vitamin _B9 . Folic acid is an essential vitamin for the biosynthesis of the base components that make up DNA and RNA, and also has the function of reducing the blood content of homocysteine, which is one of the causative substances of heart disease, stroke, Alzheimer's disease, etc. is an important vitamin with

The recommended daily intake of folic acid for men and women aged 18 and over is 240 μg, but the average daily intake (estimated) for Japanese people is 200 μg, which is considered to be lower than in other countries. It is said. Therefore, increasing the folic acid intake of adult men and women in Japan has become an issue.

Green and yellow vegetables are one of the foods rich in folic acid. However, the amount of folic acid contained in green and yellow vegetables is about 100 to 300 μg/100 gfw (fw: fresh weight). Therefore, green and yellow vegetables containing more folic acid than ordinary green and yellow vegetables are being developed.

For example, Patent Document 1 describes adjusting the ratio of red light (R), green light (G), and blue light (B) that constitute the light irradiated to leafy vegetables when the leafy vegetables are hydroponically cultivated. and adding far-red light to the irradiation light to increase the amount of folic acid contained in leafy vegetables. Specifically, it emits RGB type LED lighting in which the ratio of the light intensity of red light, green light, and blue light is adjusted to 2.5:1:2, and far-red light with a light intensity that is half that of red light. Both far-red LED lighting is used to illuminate leafy vegetables.

Japanese Patent Application Laid-Open No. 2015-112082 Japanese Patent Application Laid-Open No. 2017-063632

According to the method described in Patent Document 1, although the folic acid content per individual leafy vegetable increases, the growth is promoted and the size of the leafy vegetable increases. In particular, in leafy vegetables that are eaten with fully matured leaves, the long irradiation time makes the size of the vegetables remarkably large, and the folic acid content per unit weight may rather decrease. Therefore, the method of Patent Document 1 is effective for increasing the folic acid content of baby leaves harvested with a short irradiation time (that is, a short growing period), but it is effective for increasing the folic acid content of mature leaves. was not very effective.

The problem to be solved by the present invention is to provide a leafy vegetable that can increase the folic acid content per unit weight regardless of the length of the growing period.

The method for producing high folic acid leafy vegetables according to the present invention, which has been made to solve the above problems,
A method for producing leafy vegetables by cultivating the period from sowing to harvesting using a culture solution containing fertilizer components necessary for growing leafy vegetables,
Among the above-mentioned periods, in the growth period, which is the cultivation period from growth to a predetermined size to harvesting, the concentration range of zinc ions is 0.1 to 20 ppm, and phosphorus is contained in the form of polyphosphate ions. It is characterized in that a growth period medium is used.

The present invention provides that folic acid is one of the substances involved in the biosynthesis of DNA and RNA, that zinc ions (Zn ²⁻ ) and magnesium ions (Mg ²⁻ ) are involved in folic acid metabolism, and further Focusing on the fact that the biosynthesis of DNA and RNA is promoted and the metabolism of folic acid is activated when the intensity of the light irradiated to the plant is increased during the growth period, the concentration of these zinc ions and magnesium ions in the culture medium is and the intensity of irradiation light during the growth period as candidate factors that affect the increase in the folic acid content of leafy vegetables.

The culture solution used in hydroponics of plants generally contains zinc ions and magnesium ions, but the amount is set at a nearly constant value based on the results of long-term plant growth test research. ing. In particular, phosphorus (P), one of the three major components of fertilizers, exists as inorganic phosphate ions (PO ₄ ^3- ) in the culture solution. (Zn ₃ (PO ₄ ) ₂ , Mg ₃ (PO ₄ ) ₂ ), the contents of Zn and Mg are is set.

On the other hand, the present inventor reviewed the composition of the culture medium and found that the content of zinc ions and magnesium ions can be increased by using polyphosphate ions instead of inorganic phosphate ions. Polyphosphoric acid has been conventionally used as a food additive, so there is no problem with food safety. In addition, polyphosphate ions do not form insoluble salts even if the culture solution contains high concentrations of zinc ions and high concentrations of magnesium ions. Therefore, the concentration of zinc ions and magnesium ions in the culture solution during the growth period (culture solution for the growth period) was changed, and the intensity of the irradiation light was changed, and the results of actually hydroponic cultivation of leafy vegetables , the folic acid content of harvested leafy vegetables increased when the concentration range of zinc ions ranged from 0.1 to 20 ppm. The method for producing high-folate leafy vegetables of the present invention reflects the above results. The polyphosphoric acid used in the present invention may be composed of two or more phosphoric acid structural units, regardless of the number of structural units, but tripolyphosphoric acid is preferred because it is readily available.

Conventionally, the concentration range of zinc ions in a general culture medium is 0.05 to 0.09 ppm. It is about 1.1 times to 400 times the conventional one. It should be noted that even if leafy vegetables were hydroponic during the growth period using a culture solution containing such a high concentration of zinc ions, the amount of growth was substantially the same as when using a conventional culture solution. Therefore, it was found that increasing the concentration of zinc ions in the culture medium for the growing period had little effect on the growth of leafy vegetables.

In the method for producing high-folate leafy vegetables of the present invention, the concentration range of zinc ions contained in the culture medium for the growing period is preferably 1 to 10 ppm.

Furthermore, in the method for producing high-folate leafy vegetables of the present invention, more preferably, the zinc ion concentration range and the magnesium ion concentration range contained in the culture medium for the growth period are 10 to 20 ppm and 12 to 100 ppm, respectively. Alternatively, the concentration range of zinc ions is 0.1-20 ppm and the concentration range of magnesium ions is 48-100 ppm.

When the concentrations of zinc ions and magnesium ions are within the above ranges, it is possible to obtain high-folate leafy vegetables with a higher content of folic acid in the leaves than conventional general leafy vegetables.
Conventionally, the concentration range of magnesium ions in a general culture solution is 24 ppm, and compared with this, the concentration range of magnesium ions in the above-mentioned culture solution for the growth period is about 0.5 times to 4.2 times the conventional concentration range. be doubled.

Furthermore, in the method for producing high-folate leafy vegetables of the present invention, the folic acid content of harvested leafy vegetables increased when irradiated with light of 100 μmol/m ² /s or more during the growth period.
Therefore, in the method for producing high-folate leafy vegetables of the present invention, it is preferable to irradiate light at 100 μmol/m ² /s or more during the growth period.
By setting the cultivation conditions during the growth period to the conditions described above, it is possible to produce leafy vegetables with a higher folic acid content than conventional leafy vegetables, and high-folate leaves containing folic acid of 500 μg/100 g fresh weight or more. You can get vegetables.

By the way, zinc is one of the essential elements for the human body, and its deficiency is known to cause dermatitis, dysgeusia, and the like. Therefore, for the purpose of increasing the zinc content in leafy vegetables, a method for cultivating leafy vegetables using a culture solution containing zinc at a concentration higher than conventionally, 2 to 10 ppm, has been proposed (for example, patent Reference 2). Although the method described in Patent Document 2 has a different purpose from that of the present invention, it is in common with the present invention in that it uses a culture solution with a zinc concentration higher than that of the conventional method.

However, since Patent Document 2 does not mention the type of phosphate ions, it is thought that zinc ions are contained as inorganic phosphate ions, similar to conventional general culture solutions, and when the concentration of zinc ions is increased, the zinc ions become insoluble. It is assumed that salts are formed. Therefore, it seems that the method described in Patent Document 2 cannot be expected to have the effect of increasing the folic acid content in leafy vegetables as in the present invention.

According to the present invention, leafy vegetables with an increased folic acid content per unit weight can be obtained regardless of the length of the growing period.

FIG. 4 is an explanatory diagram of a cultivation period of a hydroponic cultivation method according to an embodiment of the present invention; 1 is a graph showing the relationship between folic acid content in Komatsuna leaves and light intensity, which is one of the results of Experiment 1. FIG. 1 is a graph showing the relationship between the content of folic acid in Komatsuna leaves and the Mg concentration in the culture medium, which is one of the results of Experiment 1. FIG. A graph showing the relationship between the folic acid content in Komatsuna leaves and the Zn concentration in the culture medium, which is one of the results of Experiment 1. 1 is a graph showing the relationship between the content of folic acid in Komatsuna leaves and the amount of Zn, which is one of the results of Experiment 1. FIG. FIG. 10 is a graph showing the results of Experiment 2 and showing the relationship between the amount of folic acid contained in green Batavia leaves and the amount of Zn contained in Green Batavia leaves. FIG. Fig. 3 shows the results of Experiment 3, and is a graph showing the relationship between the folic acid content in Komatsuna leaves and the Zn concentration after Zn was added during the growth period. 4 is a graph showing the relationship between the folic acid content in leaves of Komatsuna and Green Batavia and the nitrogen concentration in the culture medium, which is the result of Experiment 4. FIG. The figure which is a result of Experiment 5 and shows the kind of folic acid contained in the leaves of Komatsuna and Green Batavia. A graph showing the relationship between the riboflavin content in Komatsuna leaves and the Zn concentration and Mg concentration in the culture medium, which is one of the results of Experiment 6. 10 is a graph showing the relationship between the pyridoxine content in Komatsuna leaves and the Zn and Mg concentrations in the culture medium, which is one of the results of Experiment 6. FIG. A graph showing the relationship between the niacin content in Komatsuna leaves and the Zn concentration and Mg concentration in the culture medium, which is one of the results of Experiment 6. 10 is a graph showing the relationship between the thiamin content in Komatsuna leaves and the Zn and Mg concentrations in the culture medium, which is one of the results of Experiment 6. FIG. A graph showing the relationship between the riboflavin content in leaves of Komatsuna and Green Batavia, the type of irradiation light, and the nitrogen concentration in the culture medium, which is one of the results of Experiment 7. 10 is a graph showing the relationship between the content of pyridoxine in leaves of Komatsuna and Green Batavia, the type of irradiation light, and the nitrogen concentration in the culture medium, which is one of the results of Experiment 7. FIG. 7 is a graph showing the relationship between the niacin content in leaves of Komatsuna and Green Batavia, the type of irradiation light, and the nitrogen concentration in the culture medium, which is one of the results of Experiment 7. FIG. A graph showing the relationship between the thiamine content in leaves of Komatsuna and Green Batavia, the type of irradiation light, and the nitrogen concentration in the culture solution, which is one of the results of Experiment 7.

Hereinafter, the method for producing high-folate vegetables, the culture solution for high-folate vegetables, and the high-folate vegetables according to the present invention will be described with reference to specific examples. INDUSTRIAL APPLICABILITY The present invention is applicable to leafy vegetables that can be hydroponic.

Komatsuna and green batavia, which are leafy vegetables, were used in the following examples. Komatsuna is a vegetable of the cruciferous family, and green batavia is a vegetable of the Asteraceae family. The present invention can also be applied to leafy vegetables other than Japanese mustard spinach and green batavia, such as bok choy, which is a vegetable of the cruciferous family, chima lettuce, which is a vegetable of the Asteraceous family, cos lettuce, leaf lettuce, chrysanthemum, and green wave.

(1) Cultivation device Seedling raising device: This device consists of a container body in which a culture solution is stored, a plurality of seedling raising bases arranged thereon, a culture solution supply channel and discharge channel connected to the container body, and a pump. , the supply and discharge of the culture solution into and out of the container body are performed by the supply path and the discharge path. Each seedling base has a sowing hole, and one seed is accommodated in each hole. The lower part of the seedling base is immersed in the culture solution, and the seeds placed in the holes are immersed in the culture solution. The seedling-raising apparatus is used during the period from seeding to germination (germination period) and from germination to growth to a predetermined size (seedling-raising period) during the cultivation period of vegetables.

Growth device: This device comprises a container body in which the culture solution is stored, a plastic panel placed on the container body, a culture solution supply and discharge channel and a pump connected to the container body. ing. As in the seedling-raising apparatus, the culture solution is supplied to and discharged from the container main body through the culture solution supply path and the culture solution discharge path. The panel has a number of holes and the seedling base is placed over each hole. The roots of plants grown on the seedling base are immersed in the culture medium through the holes. Seedlings grown to a predetermined size in the above seedling-raising apparatus are transplanted to a growing apparatus and cultivated in the growing apparatus until harvest. In other words, the growing apparatus is used during a period (growing period) during which the seedlings grown to a predetermined size are cultivated until they are harvested during the cultivation period of the vegetables.

(2) Preparation of culture medium In this example, a culture medium having the following composition (corresponding to the growth period culture medium of the present invention; hereinafter referred to as "Mg-Zn adjusted culture medium") was used as the culture medium for the growth period. Using.

・NO ₃ ^- (nitrate ion): 530 to 550 ppm
・Ca (calcium): 150ppm
・K (potassium): 370 ppm
・Na (sodium): 17 ppm
・ S (sulfur): 80 ppm
・P (phosphorus): 25 ppm
・Mg (magnesium): 5 to 72 ppm
・B (boron): 0.05 ppm
・Cu (copper): 0.06 ppm
・Fe (iron): 2.7 ppm
・Mn (manganese): 0.08 ppm
・Mo (molybdenum): 0.02 ppm
・Zn (zinc): 0.01 to 20 ppm

The unit ppm of each composition described above indicates a weight ratio. In addition, in the culture medium, all compositions other than nitrate ions are present as ions, but in this specification, for convenience, they are denoted by the same symbol without distinguishing between them (that is, both magnesium and magnesium ions are referred to as " Mg”). In addition, P is added as potassium tripolyphosphate, Zn is added in the form of nitrate, and Mg is added in the form of sulfate to the Mg-Zn adjusted culture medium.

(3) Cultivation period As shown in Fig. 1, the cultivation period is divided into the period from sowing to germination (germination period), the period from germination to transplantation (seedling period), and the period from transplantation to harvest (growth period). rice field. For example, in the case of Japanese mustard spinach, the germination period is about 3 to 5 days, the seedling raising period is about 9 to 10 days, the growth period is about 3 to 4 weeks, and the period from sowing to harvesting is about 5 to 6 weeks. Note that when a plurality of seeds are sown in the seedling-raising apparatus, not all the seeds germinate all at once.

Therefore, in the following experiments, in order to arrange the cultivation days, the germination period was set to 4 days after sowing, and the seedling-raising period was set to 4 days to 14 days after sowing. Then, on the 14th day after sowing, the plants grown in the seedling-raising apparatus were transplanted from the seedling-raising apparatus to the growth apparatus, and then hydroponic in the growth apparatus for 3 to 4 weeks. In other words, the growth period is 3 to 4 weeks from the 14th day after sowing. During the germination period, water was used in order to equalize the effects of the composition of the culture medium on the germinated seeds, and during the seedling-raising period, a conventional, general formulation culture medium was used. Also, during the growth period, a Mg/Zn-conditioned medium was used.

In this example, the cultivation period was divided into a germination period, a seedling raising period, and a growing period based on the number of days from seeding. It is also possible to divide into For example, the plant body may be transplanted from the seedling-raising apparatus to the growing apparatus on condition that the plant height exceeds 5 cm.

<Experiment 1>
(1) Conditions Hydroponics of Komatsuna was carried out over the above-described cultivation period (germination period, seedling-raising period, and growth period) using the seedling-raising apparatus and growing apparatus described above.
As the culture solution for the seedling-raising period, a normal prescription culture solution was used, and as the culture solution for the growth period, an Mg/Zn-adjusted culture solution with a Zn concentration of 0.01 to 10 ppm and an Mg concentration of 5 to 72 ppm was used.

In addition, during the entire cultivation period, the plants were cultivated under the conditions of 12 hours light period and 12 hours dark period using fluorescent LED lighting (manufactured by Raytron Co., Ltd.). However, the light intensity of the LED was fixed at 80-100 μmol/m ² /s during the germination period and seedling raising period, and five different light intensities (40-60 μmol/m ² /s, 80-100 μmol/m ² /s, 120-150 μmol/m ² /s, 300-350 μmol/m ² /s, 600-700 μmol/m ² /s).

(2) Results (2-1) Relationship between light intensity of LED lighting and folic acid content Fig. 2A shows the start of the growth period when using a Mg Zn adjusted culture solution with a Zn concentration of 10 ppm and a Mg concentration of 48 ppm. Fig. 2 shows the relationship between the amount of folic acid contained in Komatsuna leaves harvested two weeks after culturing and the light intensity. Folate content was determined using a microbial assay.
The figure shows that the folic acid content increases as the light intensity of the LED illumination increases. Also, according to the Food Composition Tables (2016), the amount of folic ^acid contained in common Komatsuna leaves is 110 μg/100 g fw. The folic acid content of was over 1000 μg/100 g fw, and the folic acid content could be increased more than 9-fold.

(2-2) Relationship between Mg concentration in culture medium and folic acid content in leaves 2 shows the relationship between folic acid content and Mg concentration in Komatsuna leaves harvested two weeks after the start of the growth period when the intensity was set at 250 to 270 μmol/m ² /s. Folate content was determined using a microbial assay.
From the figure, the folic acid content when the Mg concentration of the culture solution was 5 ppm was about 400 μg/100 g fw, which exceeded the folic acid content of the conventional Komatsuna. In addition, although the folic acid content increased as the Mg concentration of the culture medium increased, the rate of increase was smaller when the Mg concentration increased from 36 to 72 ppm compared to when the Mg concentration increased from 5 to 36 ppm. .

(2-3) Relationship between Zn concentration in culture medium and folic acid content in leaves 2 shows the relationship between the folic acid content and the Zn concentration contained in Japanese mustard spinach harvested two weeks after the start of the growth period when the light intensity was set to 250 to 270 μmol/m ² /s. Folate content was determined using a microbial assay.
From the figure, the folic acid content when the Zn concentration in the culture solution was 0.1 ppm was about 800 μg/100 g fw, which exceeded the folic acid content of conventional Komatsuna. In addition, although the folic acid content increases as the Zn concentration in the culture solution increases, the rate of increase is higher during the period when the Zn concentration increases from 0.01 to 1 ppm, and during the period when the Zn concentration increases from 1 to 10 ppm. was small.

(2-4) Relationship between Zn concentration in leaves and folic acid content in leaves FIG. ² /s, the relationship between the amount of folic acid and the amount of Zn contained in Komatsuna leaves harvested two weeks after the start of the growth period. In this experiment, the Zn concentration in the Mg/Zn-adjusted culture medium was adjusted so that the amount of Zn contained in Komatsuna leaves at the time of 2 weeks from the start of the growth period was different. I haven't checked the value. The folic acid content was measured using a microbial assay, and the Zn content was measured using ICP (Inductively Coupled Plasma) emission spectrometry.

The figure shows that there is a positive correlation between the content of folic acid in the leaves and the content of Zn. This confirmed that the increase in the Zn content in Komatsuna leaves resulted in an increase in the folic acid content.

In addition, in the above experimental results (2-1) to (2-4), even if the Zn concentration and Mg concentration in the Mg/Zn-adjusted culture medium are different, or even if the Zn concentration in the leaves is different, , no significant difference was observed in the amount of growth of Komatsuna. From this, it was presumed that the Zn concentration and Mg concentration in the culture solution during the growing period had little effect on the growth of Komatsuna.

<Experiment 2>
(1) Conditions Using the same seedling-raising apparatus and growing apparatus as in Experiment 1, hydroponics of Green Batavia was carried out during the aforementioned cultivation period (germination period, seedling-raising period and growth period).
Cultivation conditions during the germination period and seedling raising period were the same as in Experiment 1. On the other hand, during the growth period, a Mg·Zn-conditioned culture medium with a Mg concentration of 48 ppm was used, and the light intensity of the LED illumination was set to 250 to 270 μmol/m ² /s. Also, in this experiment, the Zn concentration in the Mg-Zn-adjusted culture medium was appropriately adjusted so that the amount of Zn contained in the green batavia leaves was different. The folic acid content was measured using a microbial assay, and the Zn content was measured using ICP (Inductively Coupled Plasma) emission spectrometry.

(2) Results FIG. 3 shows the relationship between the amount of folic acid and the amount of Zn contained in green batavia leaves harvested two weeks after the start of the growth period. The folic acid content was measured using a microbial assay, and the Zn content was measured using ICP (Inductively Coupled Plasma) emission spectrometry.

From the figure, it was found that there is a positive correlation between the folic acid content and the Zn content when the Zn concentration in the leaves is in the range of 0.2 to 1.0 mg/100 g fw. On the other hand, when the Zn concentration in leaves was 1.0 mg/100 g fw or more, the folic acid content was substantially constant. From this result, it was presumed that a Zn concentration of 1.0 mg/100 g fw in the leaves was sufficient to increase the folic acid content in the leaves of Green Batavia.

Moreover, in this experiment, even if the Zn concentration in the leaves was different, no significant difference was observed in the amount of growth of green batavia. From this, it was presumed that the Zn concentration in the culture solution during the growth period had little effect on the growth of green batavia.

<Experiment 3>
(1) Conditions Using the same seedling-raising apparatus and growth apparatus as in Experiment 1, Komatsuna was cultivated in hydroponics during the cultivation period (germination period, seedling-raising period, and growth period) described above.
Cultivation conditions during the germination period and seedling raising period were the same as in Experiment 1. On the other hand, during the growth period, the Zn concentration was adjusted to a low concentration (0.01 ppm) and the Mg concentration was adjusted to 48 ppm. Then, the Zn concentration in the culture solution was changed to 5 ppm, 10 ppm, and 20 ppm, and cultivation in the growing apparatus was continued. Also, the light intensity of the LED lighting was set to 250 to 270 μmol/m ² /s.

(2) Results Fig. 4 shows the relationship between the amount of folic acid contained in Komatsuna leaves harvested one week after the addition of Zn (three weeks after the start of the growth period) and the amount of Zn added. there is In FIG. 4, "cont" indicates the results of a control example in which Zn was not added and cultivation was continued for 3 weeks. Folate content was determined using a microbial assay.

The figure shows that the folic acid content in the leaves increases even when the Zn concentration in the culture medium is increased during the growth period, and that the more Zn added, the greater the increase in the folic acid content. rice field.

Nitrogen (N) is included in the atoms constituting folic acid. Therefore, in order to investigate the effect of nitrogen (N) that constitutes zinc nitrate added during the growth period, the amount of folic acid contained in Komatsuna leaves when potassium nitrate (KNO ₃ ) was added instead of zinc nitrate was measured. Examined. As a result, addition of potassium nitrate did not increase folic acid content. From this, it was demonstrated that the effect of increasing the content of folic acid was due to zinc ions in the culture medium.

<Experiment 4>
(1) Conditions Using the same seedling-raising apparatus and growth apparatus as in Experiment 1, Komatsuna and Green Batavia were hydroponic during the cultivation period (germination period, seedling-raising period, and growth period) described above.
Cultivation conditions during the germination period and seedling raising period were the same as in Experiment 1. On the other hand, during the growth period, an Mg/Zn-conditioned culture solution with a Zn concentration of 10 ppm and an Mg concentration of 48 ppm was used. The light intensity of the LED illumination was set at 250-270 μmol/m ² /s. In addition, as a comparative experiment to Experiment 3 , Komatsuna and Green Batavia were hydroponic under the same conditions as in Experiment 3 , except that the nitrogen (N) concentration in the culture solution during the growth period was reduced to 1/2.

(2) Results FIG. 5 shows the amount of folic acid contained in leaves of Japanese mustard spinach and green batavia harvested two weeks after the start of the growing period. In FIG. 5, "N1/2" indicates the results of the comparative experiment, and those without "N1/2" indicate the results of Experiment 3 . The folic acid content was measured using the microbial assay method.

From the figure, it was found that even if the nitrogen concentration in the culture solution during the growth period was reduced by half, the folic acid content in the leaves remained almost unchanged. From this experiment, it was confirmed that the nitrogen concentration in the culture medium had little effect on the increase in folic acid content.

<Experiment 5>
(1) Conditions Part of the folic acid contained in leafy vegetables is in the form of polyglutamic acid, which is considered to be a storage form. Polyglutamic acid folic acid is converted to free folic acid by the enzyme conjugase. Therefore, in order to investigate whether the folic acid contained in Komatsuna and Green Batavia obtained in Experiment 4 described above is in the storage type or the free type, the folic acid content before and after the folic acid extracted from the leaves was treated with an enzyme was measured using a microbial assay. Actinase E (37°C, 2.5 hours) and Conjugase E (37°C, 16 hours) were used for the enzymatic treatment. The enzymatic treatment does not change the free form of folic acid, but converts the stored form of folic acid into the free form. Microbiological assays detect free folic acid but not stored folic acid. Therefore, when the folic acid content after enzyme treatment is higher than the folic acid content before enzyme treatment, it means that stored folic acid has been converted to free folic acid.

FIG. 6 shows the measurement results of folic acid extracted from Komatsuna and Green Batavia leaves two weeks after the beginning of the growth period before and after enzymatic treatment. From FIG. 6, about half of the folic acid contained in Green Batavia was in the storage polyglutamic acid form, whereas most of the folic acid contained in Komatsuna was in the free polyglutamic acid form.

As vitamin B other than folic acid (B9), riboflavin (B2), niacin (B3), pyridoxine (B6), and thiamine (B1) are known. known to be involved. In addition, the biosynthesis of the five B vitamins including folic acid is linked. Therefore, factors affecting the increase in content in Komatsuna leaves were also examined for the four types of vitamin B mentioned above.

<Experiment 6>
(1) Conditions Using the same seedling-raising apparatus and growth apparatus as in Experiment 1, Komatsuna was cultivated in hydroponics during the cultivation period (germination period, seedling-raising period, and growth period) described above.
Cultivation conditions during the germination period and seedling raising period were the same as in Experiment 1. On the other hand, during the growth period, the Zn concentration and the Mg concentration in the Mg/Zn-adjusted culture solution were set to any of the following, and hydroponics was performed.
+Zn: 5 ppm
+Mg: 48 ppm
- Zn: 0.5 ppm
-Mg: 14ppm
Ingredient table: Zn = 0.2 ppm, Mg = 12 ppm

(2) Results FIGS. 7A to 7D show the relationship between the contents of riboflavin, pyridoxine, niacin, and thiamine, and the Zn concentration and Mg concentration in the culture medium, respectively. In these figures, the results described as, for example, "+Zn, -Mg" are the results of using an Mg/Zn-conditioned culture solution adjusted to a Zn concentration of 5 ppm and an Mg concentration of 14 ppm. Also, the results described as "ingredient table" are the results of using a conventional normal prescription culture medium adjusted to a Zn concentration of 0.2 ppm and an Mg concentration of 12 ppm.

From these figures, it can be seen that the content of riboflavin, pyridoxine, niacin, and thiamine in leaves was reduced by using the Mg/Zn-adjusted culture medium in which either the Zn concentration or the Mg concentration was higher than that of the normal formulation culture medium. was found to increase.

<Experiment 7>
(1) Conditions Using the same seedling-raising apparatus and growth apparatus as in Experiment 1, Komatsuna and Green Batavia were hydroponic during the above-described cultivation period (germination period, seedling-raising period, and growth period).
Cultivation conditions during the germination period and seedling raising period were the same as in Experiment 1. On the other hand, during the growth period, the Zn concentration was adjusted to 5 ppm and the Mg concentration was adjusted to 48 ppm, using an Mg-Zn adjusted culture medium, and a blue LED light source or an RGRB (Red, Green, Blue) light LED light source ( All of them were manufactured by Raytron Co., Ltd.). In the comparative example, the Zn concentration was adjusted to 5 ppm, the Mg concentration was adjusted to 48 ppm, the nitrate concentration was adjusted to 1/2, and an RGRB LED light source was used.

(2) Results FIGS. 8A to 8D show the relationship between the contents of riboflavin, pyridoxine, niacin, and thiamine in Komatsuna and Green Batavia leaves, the type of irradiation light, and the nitrogen concentration in the culture solution, respectively. . In these figures, for example, the results marked with " N /2" are the results of the comparative example, and the others are the results of Experiment 7.

As can be seen from these figures, it was speculated that the nitrogen concentration in the culture medium affected the increase in the content of riboflavin, pyridoxine, niacin, and thiamine in the leaves. Also, for green batavia, it was speculated that blue light affects the increase of riboflavin content and thiamine content in leaves.

Based on the results of Experiments 1 to 7, Table 1 shows the results of summarizing the factors that affect the increase in the content of each vitamin B and the degree of their influence. In Table 1, the greater the number of "+", the greater the influence.

From Table 1, it can be seen that the Zn concentration in the culture medium during the growth period is a factor that affects the increase in leaf content of all five types of B vitamins. On the other hand, depending on the type of vitamin B, the Mg concentration, nitrate concentration, light intensity, and blue light in the culture medium were divided into factors affecting the increase in vitamin B content and cases not affecting it.

Claims (8)

A method for producing leafy vegetables by cultivating the period from sowing to harvesting using a culture solution containing fertilizer components necessary for growing leafy vegetables,
Among the above-mentioned periods, in the growth period, which is the cultivation period from growth to a predetermined size to harvesting, the concentration range of zinc ions is 0.1 to 20 ppm, and phosphorus is contained in the form of polyphosphate ions. A method for producing high-folate leafy vegetables, wherein a growing season medium is used. In the method for producing high folic acid leafy vegetables according to claim 1,
A method for producing high-folate leafy vegetables, wherein the concentration range of zinc ions contained in the culture solution for the growing period is 1 to 10 ppm. In the method for producing high folic acid leafy vegetables according to claim 1,
A method for producing high-folate leafy vegetables, wherein the zinc ion concentration range and the magnesium ion concentration range contained in the growth period culture medium are 10 to 20 ppm and 12 to 100 ppm, respectively. In the method for producing high folic acid leafy vegetables according to claim 1,
A method for producing high-folate leafy vegetables, wherein the concentration range of magnesium ions contained in the culture solution for the growing period is 48 to 100 ppm. In the method for producing high folic acid leafy vegetables according to any one of claims 1 to 4,
A method for producing high-folate leafy vegetables, wherein the polyphosphate ions contained in the culture solution for the growing period are tripolyphosphate ions. In the method for producing high folic acid leafy vegetables according to any one of claims 1 to 5,
A method for producing a high-folate leafy vegetable, characterized by irradiating with light of 100 μmol/m 2 /s or more during the growth period. In the method for producing high folic acid leafy vegetables according to any one of claims 1 to 6,
A method for producing a high-folate leafy vegetable, wherein the leafy vegetable has a folic acid content of 500 μg/100 g fresh weight or more. A method for producing high-folate leafy vegetables by cultivating leafy vegetables using a culture solution containing fertilizer components necessary for growing leafy vegetables during the period from sowing to harvesting,
The period includes a germination period during which the seedlings are cultivated in the seedling-raising apparatus from sowing to germination, a seedling-raising period during which the seedlings germinated in the seedling-raising apparatus are cultivated in the seedling-raising apparatus until they grow to a predetermined size, and When a seedling grown to a predetermined size is transplanted from the seedling-raising apparatus to a growing apparatus and divided into growing periods, which are periods of cultivation until harvesting in the growing apparatus,
In the growth period, a growth period culture solution containing magnesium ions in the concentration range of 12 to 100 ppm, zinc ions in the concentration range of 0.1 to 20 ppm, and containing phosphorus in the form of polyphosphate ions is used. A method for producing high folic acid leafy vegetables.

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