JPH0439968B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for preserving the freshness of harvested agricultural products, and more specifically, the present invention is characterized by using oligosaccharides that have a growth-promoting effect on agricultural products selected from vegetables, flowers, and fruits. The present invention relates to a method for preserving the freshness of harvested agricultural products. [Conventional techniques and their problems] The production and consumption of vegetables and flowers has been increasing year by year, with changes in the product composition due to diversification of lifestyles. However, the production volume of vegetables and flowers varies greatly depending on weather conditions, resulting in significant price fluctuations, and an important measure to stabilize prices is to establish technology to maintain the freshness of crops such as vegetables and flowers after harvest. is strongly requested. Conventional freshness preservation techniques include 1) methods to extend the storage period by adjusting temperature, environmental gas composition, etc.;
2) radiation irradiation method, 3) method using plastic film, etc., but the stable storage conditions for plants vary depending on each plant, there are safety issues, and the above treatments themselves are costly. It was the cause of Furthermore,
Since these methods are not perfect, there is a limit to how long they can maintain freshness, so there is a need for the development of safe and inexpensive techniques for preserving plant freshness that can extend the storage period compared to conventional methods. I've been exposed to it. On the other hand, in recent years, it has been reported that oligosaccharides obtained through the decomposition of polysaccharides that constitute the cell walls of plants play an important role as regulators of the plant's own biological defense responses and induction of differentiation. It's starting to feel like this. For example, when oligogalacturonic acid prepared from plant cell walls acts on soybeans, it promotes the synthesis of certain antibacterial substances (phytoalexins) and enhances resistance to pathogenic bacteria. The actions of such oligosaccharides differ from those of plant hormones, and their actions are said to be specific rather than pleiotropic. [Means for Solving the Problems] The present inventors focused on the special effects of oligosaccharides and, as a result of intensive studies, found that some oligosaccharides have an effect on plant growth, especially on roots. They found that plants grown with the application of such oligosaccharides had a longer freshness period than plants grown without the addition of oligosaccharides and that The present invention was completed based on the discovery that if the roots and stems of cultivated plants are immersed in an aqueous solution of oligosaccharides that promote plant growth and the oligosaccharides are absorbed into the plant body, the freshness period can be extended. That's what I came to do. That is, the present invention relates to a method for maintaining the freshness of agricultural products selected from vegetables, flowers, and fruits after harvesting, which is characterized by using oligosaccharides having a plant growth promoting effect. Agricultural crops suitable for the present invention include vegetables such as daikon radish, komatsuna, sunny lettuce, spinach, and radish, as well as flowers, fruit trees, and the like. Oligosaccharides having a plant growth promoting effect according to the present invention include alginate oligosaccharides, glucomannan oligosaccharides, polygalactyuronic acid oligosaccharides, xylooligosaccharides, agarooligosaccharides, cellooligosaccharides, inulooligosaccharides, and plant cell wall polysaccharides. Oligosaccharides obtained by decomposition, pectin oligosaccharides,
These include mannan oligosaccharides, fucoidin oligosaccharides, gum arabic oligosaccharides, polyethylene glycol alginate oligosaccharides, carrageenan oligosaccharides, etc.
The plant growth promoting effect of each oligosaccharide is explained in detail in JP-A-63-101302. The oligosaccharides having a plant growth promoting effect according to the present invention are defined as follows. Alginate oligosaccharide is defined as follows. Decomposed products obtained by decomposing alginic acid, sodium alginate, derivatives of alginic acid, alginic acid-containing algae such as kelp, other glycosides derived from microorganisms with enzymes such as alginate lyase, or hydrolyzing with acids such as hydrochloric acid. , or an oligosaccharide composition which is its main component, and the constituent sugar components of the oligosaccharide are mainly guluronic acid and mannuronic acid. A composition consisting of an oligosaccharide consisting of only guluronic acid, only mannuronic acid, or a combination of guluronic acid and mannuronic acid, and guluronic acid and mannuronic acid with a degree of polymerization of 2 to 20, and furthermore, this composition 4, refers to a composition obtained by heating under conditions of 100 to 120°C for 15 to 180 minutes. Glucomannan oligosaccharide is defined as follows. Endo-1,4,- etc. containing glucomannan or glucomannan
A decomposition product obtained by hydrolyzing glucomannan with an enzyme that can use it as a substrate, such as β-D-mannanase, or by hydrolyzing it with an acid such as hydrochloric acid, or an oligosaccharide that is the main component thereof.
The constituent sugar components of oligosaccharides are mannose and glucose, and refer to oligosaccharides and compositions thereof having a degree of polymerization of 2 to 10. Such a composition is prepared, for example, as follows. As a raw material, glucomannan or konjac yam containing glucomannan can be used. As a means of decomposing glucomannan, a method of hydrolyzing it with acids such as hydrochloric acid and sulfuric acid, and a method of decomposing it with an enzyme such as mannanase can be applied. For example, add 100 parts of water to 2 parts of glucomannan to make an aqueous solution, then add 3 parts of concentrated hydrochloric acid to 90%
Glucomannan oligosaccharide can be prepared by hydrolyzing at ~100°C for 1 to 4 hours, filtering, neutralizing the liquid with caustic soda, and concentrating. In addition, when decomposing with mannanase,
It can also be prepared by adding and dissolving 2 parts of glucomannan and 100 parts of water, adjusting the pH to the optimum pH for enzyme action, and reacting for 10 to 48 hours at the optimum temperature for enzyme action. Mannanases include enzymes produced by Rhizopus niveus and Aspergillus niger .
Commercially available cellulase preparations having mannanase activity are used. Further, the reaction solution obtained as described above can be subjected to the present invention after being decolorized using activated carbon or the like or desalted using an ion exchange resin. Polygalactyuronic acid oligosaccharide is defined as follows. A decomposition product obtained by decomposing polygalactulonic acid with an acid or an enzyme, or its main component, an oligosaccharide, whose constituent sugar component is galactulonic acid, and whose degree of polymerization is 2 to 10.
oligosaccharide. Such oligosaccharides are prepared as follows. After polygalacturonic acid was made into a 2% aqueous solution, hydrochloric acid was added to a 2% concentration, and the mixture was heated at 90 to 100℃ for 3
After hydrolysis for a period of time, the solution is neutralized, the decomposition residue is filtered, and the resulting solution is concentrated to obtain an aqueous solution containing polygalactyuronic acid oligosaccharides. When decomposing with an enzyme, it can be prepared by adjusting the pH of a 2% aqueous solution of polygalactyuronic acid to 5.0, adding 10 mg of pectinase per 1 g of substrate, and decomposing at 50°C for 6 hours. The oligosaccharide-containing liquid thus obtained can be used for the intended purpose by decolorizing it with activated carbon, or by purifying it by gel filtration or ion exchange resin, if necessary. Xylooligosaccharide is defined as follows.
β-1,3-xylan, β-1,4-xylan, or hemicellulose components of land plants such as corn cob, rice straw, and algae belonging to red and green algae such as dulse and Ivy are treated with an acid such as hydrochloric acid. Or a decomposition product produced by decomposition by an enzyme such as xylanase or its main component, an oligosaccharide whose constituent sugar is xylose and whose degree of polymerization is from 2 to 10, and its composition. say. Such oligosaccharides are prepared, for example, as follows. i.e. commercially available xylan at 2.5%
After adjusting the pH to 5.0 with an aqueous solution of (w/v), meiselase (manufactured by Meiji Seika Co., Ltd.) as a xylanase-containing enzyme was added at a rate of 10 mg per 1 g of xylan, and the mixture was reacted at 40°C for 48 hours. In the reaction solution, 66% of oligosaccharides with a degree of polymerization of 2 to 7 and 34% of oligosaccharides with a degree of polymerization of 8 or more are produced. Fractionation of each oligosaccharide can be carried out by a gel filtration method. For example, by carrying out fractionation with a column chromatography packed with Biogel P-2, the degree of polymerization is 2.
It is also possible to isolate ~7 oligosaccharides. Agarooligosaccharide is defined as follows.
A decomposition product produced by decomposing agar, agarose, agaropectin, or algae belonging to the red algae such as Amanita containing them with an acid such as hydrochloric acid or an enzyme such as agarase, or an oligosaccharide that is the main component thereof. Its constituent sugar components are galactose, 3,6-anhydrogalactose, 6-
These are O-methylgalactose, xylose, and glucuronic acid, and refer to oligosaccharides and compositions thereof having a degree of polymerization of 2 to 20. Such oligosaccharides are prepared, for example, as follows. Commercially available agarose is made into a 1% (w/v) aqueous solution, adjusted to pH 6.0, 40 units of agarase is added per 1 g of agarose, reacted at 40°C for 72 hours, and then activated carbon is added to decolorize. after that,
Desalt using an ion exchange resin to obtain agarooligosaccharide. Cellooligosaccharide is defined as follows. It can be obtained by hydrolyzing cellulose or cellulose-containing plant skeletal materials, cell membranes of microorganisms, mantle membranes of sea squirts, ascidians, etc., and cellulose derivatives such as carboxymethylcellulose with cellulase or acids such as hydrochloric acid and sulfuric acid. refers to oligosaccharides whose constituent sugar components are glucose or derivatives thereof, and whose polymers are 2 to 10, and compositions thereof. Such a composition is prepared, for example, as follows. Powdered cellulose (trade name: Avicel) was used as a raw material. To 1 part of powdered cellulose, 2 parts of hydrochloric acid and 2 parts of sulfuric acid were added. After dissolving the cellulose, another 12 parts of hydrochloric acid was added.
React for 5 hours at ~25°C. After the reaction is completed, the reaction solution is neutralized, desalted by a conventional method such as gel filtration or electrodialysis, concentrated, and if necessary, dried to obtain a cellooligosaccharide. Canine oligosaccharide is defined as follows.
A decomposition product obtained by hydrolyzing inulin or Jerusalem artichoke containing inulin with inulinase or an acid such as hydrochloric acid or oxalic acid, or an oligosaccharide whose main component is fructose and glucose. Refers to oligosaccharides and compositions thereof having a degree of polymerization of 2 to 10. Such oligosaccharides are prepared, for example, as follows. Add 4 parts of water to 1 part of Jerusalem artichoke rhizome, grind it, add oxalic acid to a final concentration of 0.1N, hydrolyze at 60°C for 1 hour, then neutralize with calcium carbonate, remove the residue, The liquid can be concentrated and, if necessary, dried to obtain inulooligosaccharide. Oligosaccharides obtained by decomposing plant cell wall polysaccharides are defined as follows. Plant cell wall polysaccharides are polysaccharides present in the plant cell wall itself or between each cell, such as cellulose, xyloglucan, xylan, β-glucan, arabinan, arabinogalactan, rhamnogalactyuronan, pectin, arabinoxylan,
It is a mixture of polysaccharides such as polygalacturonic acid and galactan, and is a decomposition product obtained by decomposing such cell wall polysaccharides with acids or enzymes, or its main component oligosaccharide. Constituent sugars are glucose, xylose, arabinose,
rhamnose, galactose, galacturonic acid,
It is a derivative of galacturonic acid, mannose, etc., and refers to an oligosaccharide mixture with a degree of polymerization of 2 to 10. Such oligosaccharides are prepared as follows. Examples of raw materials for cell wall polysaccharides include the plant itself, callus obtained by inducing callus from the plant, and a culture solution obtained by culturing callus. Furthermore, after pre-processing the plant body such as grinding, polysaccharides are extracted from the ground material using water, an alkali, a neutral salt solution, etc., and an organic compound such as alcohol is extracted from the extract. A polysaccharide separated using a solvent or the like and purified can be used. After making the polysaccharide obtained in this way into a 1-5% aqueous solution, an acid such as hydrochloric acid with a concentration of 1-5% is added and hydrolyzed at 80-150°C for 1-4 hours. Oligosaccharides can be produced in the decomposition solution. When using plant bodies or callus as raw materials, after grinding the plant bodies or callus, add 1 to 10% of hydrochloric acid etc. to the grinding solution.
5%, hydrolyzed at 80 to 100°C for 1 to 6 hours, and after neutralization, remove the decomposition residue by filtration, etc.
An oligosaccharide-containing liquid can be prepared. Also,
When decomposing with an enzyme, the pH of the 1-5% aqueous solution of cellular polysaccharide obtained as above or the ground material of the plant body or callus is determined by determining the optimum action of the enzyme used.
Adjust the pH to 4-48 under the enzyme's optimal working temperature conditions.
Oligosaccharides can be obtained by time decomposition. As cell wall polysaccharides contain a wide variety of polysaccharides, it is desirable to use enzymes that have degrading activity against a wide variety of substrates, and cellulase preparations are suitable enzymes for this purpose. is particularly desirable. Examples of enzyme agents include Meicelase (manufactured by Meiji Seika Co., Ltd.), Cellulase Onozuka R-10 (manufactured by Kinki Yakult Manufacturing Co., Ltd.), Cellulase Ap (manufactured by Amano Pharmaceutical Co., Ltd.), and Macerozyme (manufactured by Yakult Co., Ltd.). (manufactured by). The amount of the enzyme agent added is preferably 1 to 50 mg per 1 g of polysaccharide serving as a substrate. Pectin oligosaccharide is defined as follows. A decomposition product obtained by decomposing pectin with acid or enzyme, or its main component oligosaccharide, whose constituent sugars are galactyuronic acid and its galactyuronic acid methyl ester, and whose degree of polymerization is 2 to 10. means. Pectin oligosaccharides can be prepared in the same manner as polygalactyuronic acid oligosaccharides. Mannan oligosaccharide is defined as follows. Mannan (β-1,4-mannan, β-1,
3-mannan, α-1,6-mannan, etc.) or mannan-containing zouge palm seeds, miru (green algae), metabolic products of yeast and filamentous fungi, etc., by decomposing them with acid or enzymes such as mannanase. Refers to the obtained decomposition products or oligosaccharides that are the main component thereof, whose constituent sugar is mannose, and whose degree of polymerization is 2 to 10, and their compositions. Such oligosaccharides are prepared, for example, as follows. After dissolving 4 parts of yeast mannan in 100 parts of hot water, 100 parts of 1N HCl solution was added, and 90 parts of yeast mannan was dissolved in 100 parts of hot water.
Hydrolysis is carried out at ~100°C for 2 hours. After the reaction is completed, the reaction solution is neutralized to obtain a decomposed product. Alternatively, if necessary, oligosaccharides with a degree of polymerization of 2 to 10 may be fractionated by column chromatography packed with Biogel P-2 or the like to obtain only oligosaccharides. Fucoidin oligosaccharide is defined as follows. A decomposition product obtained by decomposing fucoidin or fucan sulfate with an acid or an enzyme, or an oligosaccharide that is its main component, whose constituent sugar component is fucose, and whose degree of polymerization is 2 to 10, and its composition. means. Such oligosaccharides are prepared, for example, as follows. 100 parts of fucoidin derived from brown algae
After dissolving in 1 part of hot water, 100 parts of 1N HCl solution is added and hydrolysis is carried out at 90-100°C for 2-4 hours.
After the reaction is completed, the reaction solution is neutralized to obtain a decomposed product. In addition, if necessary, the degree of polymerization is 2 to 2 using column chromatography packed with Biogel P-2 or the like.
It is also possible to fractionate the 10 oligosaccharides to obtain only oligosaccharides. Gum arabic oligosaccharide is defined as follows. A decomposition product obtained by decomposing gum arabic with acids or enzymes, or an oligosaccharide that is the main component of the decomposition product, whose constituent sugar components are galactose, arabinose, rhamnose, and glucuronic acid. Refers to oligosaccharides with a degree of 2 to 10 and compositions thereof. Such oligosaccharides are prepared, for example, as follows. After dissolving 4 parts of gum arabic in 100 parts of hot water, add 100 parts of 1N HCl solution and
Hydrolysis is carried out at 100°C for 2 hours. After the reaction is complete,
Neutralize the reaction solution to obtain a decomposed product. Also, if necessary,
It is also possible to fractionate oligosaccharides with a degree of polymerization of 2 to 10 by column chromatography packed with Biogel P-2 or the like to obtain only oligosaccharides. Polyethylene glycol alginate oligosaccharide is defined as follows. A decomposition product obtained by decomposing polyethylene glycol alginic acid with acid or enzyme, or an oligosaccharide that is the main component of the decomposition product, and its constituent sugar components are polyethylene glycol guluronic acid and polyethylene glycol mannuronic acid. refers to oligosaccharides and compositions thereof with a degree of polymerization of 2 to 10. Such oligosaccharides are prepared, for example, as follows. After dissolving 4 parts of polyethylene glycol alginic acid in 100 parts of hot water, 100 parts of 1N HCl solution is added and hydrolysis is carried out at 90-100°C for 2 hours. After the reaction is completed, the reaction solution is neutralized to obtain a decomposed product. Moreover, if necessary, oligosaccharides with a degree of polymerization of 2 to 10 can be fractionated by column chromatography packed with Biogel P-2 or the like to obtain only oligosaccharides. Carrageenan oligosaccharide is defined as follows. Carrageenan or a decomposition product obtained by decomposing carrageenan or a red algae containing it belonging to the genus Tsunomata, Suginori, Ibaranori, etc. with an acid or an enzyme, or an oligosaccharide that is the main component thereof,
Its constituent sugar component is a carabiose polymer,
Refers to oligosaccharides and compositions thereof having a degree of polymerization of 2 to 10. Such oligosaccharides are prepared, for example, as follows. After dissolving 4 parts of carrageenan in 100 parts of hot water, 100 parts of 1N HCl solution was added, and 90~
Hydrolysis is carried out at 100°C for 2 hours. After the reaction is completed, the reaction solution is neutralized to obtain a decomposed product. Also, if necessary,
It is also possible to fractionate oligosaccharides with a degree of polymerization of 2 to 10 by column chromatography packed with Biogel P-2 or the like to obtain only oligosaccharides. Oligosaccharides with plant growth-promoting effects obtained in this way can be applied to seeds at a ratio of 5 to 100 γ per seed, added to soil as an aqueous solution of 0.25 to 0.00025%, or applied to leaves. Spraying or adding 1γ/
When added or mixed at a ratio of ml to 250γ/ml and applied to plants, it can promote root growth of plants, make plants healthy, and suppress water transpiration. For this reason, its freshness is maintained for a longer period of time even under normal distribution conditions. In addition, the roots and stems of plants grown under normal cultivation conditions are treated with oligosaccharides that have plant growth-promoting effects.
A similar freshness-keeping effect is also observed by immersing in a 0.00025% aqueous solution for 16 to 48 hours. [Example] Next, the present invention will be explained in detail with reference to Examples. Example 1 180 seeds of Kaiware radish were sown in a container equipped with a synthetic resin wool mat, and alginate oligosaccharides were added at 1γ/ml, 10γ/ml, 50γ/ml, 100γ/ml,
200 ml of tap water added at a rate of 250 γ/ml was added to each, and cultivation was performed for 6 days at 23° C. in the dark for 4 days and under irradiation of 5000 lux for the following 2 days. As a control, the plants were grown under the same cultivation conditions as above without the addition of alginate oligosaccharides. After cultivation, the obtained daikon radish was stored in a plastic bag, some of which was left open at 5°C, and the amount of water transpiration and how it spoiled were observed. The results are shown in Table 1.

[Table] As is clear from Table 1, the alginate oligosaccharide is 1γ/ml to 250γ/ml, preferably 100γ/ml to
Kaiware daikon radish grown with the addition of 250 γ/ml had low water transpiration and maintained good freshness. Example 2 One sunny lettuce seed was sown in a 4 cm square synthetic resin wool pine, and Otsuka House Fertilizer No. 1 0.15
%, after soaking in liquid fertilizer containing No. 2 0.1%, 23
The seeds were cultivated for 10 days under the conditions of 5,000 lux and germinated, and then planted in a hydroponic cultivation device.
It was cultivated for one month under the conditions of 8,000 lux and 23-24℃. The experimental areas are as follows. Control group: Seedlings are raised using liquid fertilizer without the addition of oligosaccharide alginate, and then cultivated using liquid fertilizer without the addition of oligosaccharide alginate. Alginate oligosaccharide addition area: After raising seedlings with liquid fertilizer added with alginate oligosaccharide 0.025%, alginate oligosaccharide
Cultivated with liquid fertilizer containing 0.025%. After cultivation, the obtained sunny lettuce was stored in a plastic bag and stored at 5°C with some parts open.
We investigated the amount of water transpiration (%) and how it was damaged. The results are shown in Table 2.

[Table] As is clear from Table 2, the freshness of the sunny lettuce grown with the addition of oligosaccharide alginate was better than that of the control. Note that the degree of damage and the amount of water evaporation were displayed in the same manner as in Example 1. Example 3 9 kg of black soil was added to a pot measuring 17 cm x 60 cm x 15 cm, and 40 seeds of Komatsuna (variety name: Misugi Komatsuna) were sown and cultivated under natural conditions for 35 days. The experimental areas are as follows. Control group: Alginate oligosaccharide-free addition group: Alginate oligosaccharide 22g or 2.2g
Make an aqueous solution of 3.6, add the entire amount to the black soil, and add the alginate oligosaccharide to the black soil.
Cultivation was carried out in soil supplemented with 0.25% or 0.025%. The komatsuna thus obtained was stored in a plastic bag, a part of which was opened, and a storage test was carried out at 5°C. The results are shown in Table 3. Note that the degree of damage was displayed in the same manner as in Example 1.

[Table] As is clear from Table 3, the freshness of Komatsuna grown with the addition of oligosaccharide alginate was better than that of the control. Example 4 9 kg of black soil was added to a 17 cm x 60 cm x 15 cm pot, 60 spinach seeds were sown, and the pot was cultivated under natural conditions using conventional fertilizer amounts and cultivation methods. After 40 days of cultivation, spinach was harvested, and the roots of 25 of the 50 spinach plants were cut and placed in plastic bags, and some were left open for storage tests at 5°C. The roots of the remaining 25 strains were immersed in an aqueous solution containing 250γ/ml alginate oligosaccharides for 16 hours, and then the roots were cut and placed in plastic bags, and some were left open for storage tests at 5°C. did. The results are shown in Table 4. Incidentally, the degree of damage and the amount of water evaporation were displayed in the same manner as in Example 1.

[Table] As is clear from Table 4, the freshness of spinach treated with oligosaccharide alginate was better than that of the control. Example 5 180 daikon radish seeds were sown in containers equipped with synthetic resin wool mats, and 200 ml of tap water containing various oligosaccharides with plant growth promoting effects at a ratio of 250 γ/ml was added to each container. ,twenty three
The plants were grown at ℃ in the dark for 4 days and then under irradiation at 5000 lux for the next 2 days. As a control, cultivation was also carried out under conditions without oligosaccharides. After cultivation is completed,
The obtained daikon radish was stored in a plastic bag, some of which was left open at 5°C, and the degree of damage was examined after 4 days of storage. The results are shown in Table 5. Note that the degree of damage was displayed in the same manner as in Example 1.

[Table] [Effects of the Invention] According to the method of the present invention, the freshness of harvested agricultural products can be maintained safely and inexpensively for a long period of time without changing storage conditions depending on the harvested agricultural products. . Therefore, by using the method of the present invention, it is possible to stabilize the prices of agricultural products such as vegetables and flowers without being influenced by natural conditions.

Claims (1)

[Scope of Claims] 1. A method for maintaining the freshness of agricultural products selected from vegetables, flowers, and fruits after harvest, characterized by using an oligosaccharide having a plant growth promoting effect. 2. The method according to claim 1, characterized in that plants selected from vegetables, flowers, and fruit trees are cultivated using the oligosaccharide having a plant growth promoting effect. 3. Claim 1, characterized in that roots or stems of vegetables and flowers are immersed in an aqueous solution containing an oligosaccharide having a plant growth promoting effect, and the aqueous solution is absorbed into the vegetables and flowers. the method of.