JPS61100153A - Maintenance of high freshness - Google Patents

Abstract

PURPOSE:A microorganism which is capable of decomposing or assimilating ethylene or an extract therefrom is contained in packages of vegetables or flowers to prevent them from overripening and keep their freshness. CONSTITUTION:A microorganism which is capable of decomposing or assimilating ethylene such as Corynebacterium equi or an extract therefrom is contained in packages of vegetables (climacteric type) and flowers (carnation). EFFECT:It is enough to use only one kind of freshness keeper. Moreover, it can be readily applied and disposed with high safety to keep good taste and color. The extract may be directly coated on the substrates.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention suppresses overripeness of fruits, vegetables, flowers, etc. during transportation or temporary storage at stores or at the consumer stage.
Regarding how to preserve its freshness.

(Prior Art) It is well known that fruits and vegetables harvested in a fully ripe state taste much better than those harvested in an unripe state.

Also, for example, cut flowers such as carnations that have not been cut for a long time are less wilted, more fragrant, and more beautiful.

However, fruits and vegetables have poor shelf life after ripening, and are particularly susceptible to softening, discoloration, bad odor, rot, etc. during the distribution stage, which significantly reduces commercial value. Therefore, in areas where fruits and vegetables are produced, a method is often used to harvest immature fruits and allow them to ripen at the distribution stage. However, with this method, the original taste of fruits and vegetables is lost, and it is also very difficult to prevent overripening.

It is well known that ethylene gas is a type of plant hormone that promotes respiration and promotes ripening, and some fruits and vegetables and flowers such as carnations emit ethylene gas by themselves even after harvesting, significantly slowing down their ripening. It is intended to promote Fruits and vegetables that fall under this category are called Klimakteritsk type fruits and vegetables, such as bananas, avocados, apples, tomatoes, melons, etc.
Oysters, pears, etc. are known.

Therefore, especially for climacteric fruits and vegetables,
A method has already been put into practical use in which ethylene absorbers or decomposers are included in fruits and vegetables to remove the ethylene generated by them.

Ethylene absorbents currently in use include activated carbon (Japanese Unexamined Patent Publication No. 49-66433) and zeolite (Japanese Unexamined Patent Publication No. 49-98057), but these are both physical adsorption agents. At low ethylene concentrations, it has a weak affinity for ethylene, so a large amount is required.Furthermore, fruits and vegetables also adsorb moisture and carbon dioxide that are generated at the same time as ethylene, resulting in a decrease in ethylene adsorption ability. In addition, as an ethylene decomposing agent, potassium permanganate (JP-A-56-18901, JP-A-5
8-20149, JP 58-220648), palladium compounds (JP 56-55147, JP 56-63048), potassium bromate (JP 56-88752) , Japanese Patent Publication No. 57-630
48 Publication), halogen gas (JP-A-57-99147)
Publication No.). However, potassium permanganate and palladium compounds are heavy metals and colored, and they elute with water, so they have drawbacks such as the difficulty of disposing of used decomposers and the inability to adhere them to fruits and vegetables. be. In addition, those using potassium bromate have the disadvantage that a strong acid, especially sulfuric acid, must be used as a catalyst (Journal of the Japanese Society of Agricultural Chemistry 57 (11m27-11
33(83)). Furthermore, since the halogen gas method is a gas-gas reaction, the halogen gas comes into direct contact with fruits and vegetables, which is not preferable.

Furthermore, in addition to the method of removing ethylene gas, methods such as oxygen scavengers, carbon dioxide gas generators, or introduction of carbon dioxide gas are also used as methods for preserving the freshness of fruits, vegetables, and flowers, depending on the type of fruits, vegetables, and flowers.

Oxygen scavengers based on iron oxide, hydrosulfide, calcium sulfite, glucose, etc. have been developed, and alkalis have been used as carbon dioxide and gas generating agents, but they cannot be used alone. If the effect is weak, it is used in combination. For example, in the case of Ome, if an ethylene remover and an oxygen absorber were used together, the freshness period could be extended by 2 to 3 days (Food-Pac
1984+8) and broccoli (Food Packaging 1
984+8) has been reported. Additionally, a report states that increasing the carbon dioxide concentration at the same time as removing ethylene gas is more effective (Kobe University Agricultural Research Report Vol. 13, p. 23i).
~'240) is also available. However, if these methods are used together, each must be sealed separately.
In other words, the number of steps increases accordingly, the use of two or more types of freshness-preserving agents is complicated, and it is also difficult to combine them appropriately.

(Means for Solving the Problems) The present invention was invented in view of the above-mentioned points, and it decomposes and removes ethylene gas by a mechanism completely different from the above-mentioned conventional method, lowers the oxygen concentration, At the same time, the present invention aims to provide a method for maintaining the freshness of fruits, vegetables, and flowers by increasing the carbon dioxide concentration.

The configuration of the present invention will be explained below.

That is, the gist of the present invention is a method for long-term preservation of fruits, vegetables, and flowers, characterized in that a microorganism having ethylene decomposition ability or ethylene assimilation ability, or an extract thereof, coexists with the fruits, vegetables, and flowers in the same package. This is a method of preserving freshness.

Here, microorganisms known as having ethylene decomposition ability or ethylene assimilation ability include, for example, Mycobacterium genus (Autonie van Leeuwenhook).
Vol. 42 (1976) 59-71), genus Nocardia (European A
pplied Microbiology and B
iote-chnology (1981) Vol.
12.39-45), Pseudomonas (Pseud
Applied Microbiota
lo-gy (1973) Vol, 26.86, 91
, Biochemistry Jour-nal (19
61) Vol, 78.69-82), Me-thylosinus genus (Journal
of General Microb-iology
(1970) Vol. 61.205-218), and in addition, the inventors have
cill-us), Aeromonas
Microorganisms of the genus S) and Serratia have also been recognized to have the ability to decompose ethylene. Specifically, the microorganisms belonging to these genera are Corynebacterium equui.
i) HIFOm3730, Mycobacterium rhodocras
chrous) HIFONa13166, Mycobacterium smegmatis (MycobacteBum
smeg-matis); [FON113167, Mycobacterium frei
phlei); IFON1113160, Mycobacterium va
ccae): IFONa14118, Mycobacterium fortuitum
fartuitum), IFOm13159, Aeromonas thermonisida (Aeromonas s.
almonicida)HIFOflh12718,
Aeromonas selmonicida 5
ubsp, masou-cida);IFONn13
784, Aeromonas punctiita
nas punctata); IFOm12717.

Therefore, the microorganisms having ethylene decomposition ability or ethylene assimilation ability in the present invention are not limited to specific microorganisms, but in short, any microorganism that has ethylene decomposition ability or ethylene assimilation ability and is non-toxic is sufficient. .

Fruits and vegetables that can be expected to have a freshness-keeping effect by applying the present invention include the aforementioned climacteric fruits and vegetables, and the same effect can also be expected for flowers such as carnations and roses. In addition, in the present invention, as a specific method of coexisting these microorganisms having ethylene decomposition ability or ethylene assimilation ability or their extracts with fruits, vegetables, or flowers, for example, the microorganisms or their extracts are directly gas-treated. A method of enclosing a product in a permeable bag with fruits and vegetables, a method of enclosing a carrier such as glass wool or filter paper with a microorganism or its extract adsorbed or absorbed in advance, and a method of enclosing a product with a microorganism or its extract adsorbed or absorbed in advance. There are two methods: enclosing a physically or chemically immobilized product; and, in the case of an extract, a method of coating the surface of the fruit or vegetable itself, which may be selected as appropriate. By the way, among the above-mentioned embodiments, the gas-permeable bag used in the method of enclosing the microorganism or its extract as it is in the gas-permeable bag with fruits and vegetables, etc., can basically be used as long as it has the property of allowing ethylene gas to pass through. However, preferably it has air permeability, moisture permeability, and water resistance (including the meaning of non-water permeability), such as cellulose film, low density polyethylene film, purified Parafilm, polybutylene film. , polycarbonate film, polypropylene film and more! Porous films or their component resins are laminated or coated on various paper or cloth substrates.

In addition, as is clear from the experiments described below, when the above-mentioned microorganisms with ethylene decomposition ability or ethylene assimilation ability or their extracts are used in a state where they retain moisture, their freshness-preserving effects are more activated. Furthermore, when coating the surface of fruits and vegetables, spraying and other treatments can be performed efficiently. However, even if they do not retain moisture, microorganisms or their extracts can retain moisture over time due to the water vapor generated from fruits and vegetables. It is not necessary to keep it hydrated as it will be effective.

(Experiment) Next, microorganisms capable of degrading ethylene were sealed in a bag.
Experiments will be explained based on the results of measuring changes in ethylene gas, oxygen, and carbon dioxide in the packaging material.

Experiment 1 Mycobacterium ferae
-ium phlei); IFOTh13160 as the first
In a culture solution having the composition shown in the table, air containing 50 ppm of ethylene was added per 11 culture solutions at 750ml/1ai.
The cells were cultured while being aerated with n. The obtained microorganisms were centrifuged (7000G, 20min). Approximately 0.5g of microorganisms are infiltrated into filter paper, and the resultant material is placed in a polypropylene bag with a thickness of 0.5g.
Δ to 11 dragon (17X23cI11), and sp
Air 2001 containing pm of ethylene was enclosed, sealed and stored at 25°C, and the air inside was sampled over time to measure the concentration of each gas. As a control, a filter containing no microorganisms (filter paper was simply impregnated with 0.1M phosphate buffer) was prepared and used in the same manner as in the present invention.

The results are shown in Table 2. As is clear from this table, it can be easily understood that microorganisms capable of decomposing ethylene reduce the ethylene and oxygen concentrations within the packaging material, and at the same time increase the carbon dioxide concentration.

Next, a method of physically and chemically immobilizing microorganisms with ethylene decomposition ability or ethylene assimilation ability or their extracts (live microorganisms, cleaning microorganisms Alternatively, the method of immobilizing the extract using a gelatinizing substance such as agar, arginine, pectin, acrylamide, etc. will be specifically explained through experiments.

Experiment 2 Mycobacterium rhodocras (My
cobacterium rhodochrous);
Using IFO11h13166, this microorganism (wet
Add distilled water to 10g) to make 100ml, suspend and mix with 100ml of 3% sodium alginate solution,
Add 0.1ml dropwise to 1.2% calcium chloride solution,
Fix it in a spherical shape. After aging for 30 minutes, the microorganisms were washed with water and allowed to stand overnight at 4°C to obtain gel-immobilized microorganisms. Wet this
After storing 0.5 g in lk biological equivalent in a polypropylene packaging material (thickness 0.11 fim, 30 x 15 cm), 1
After enclosing 200 m/200 m of 8 ppm ethylene-added sterile air, it was sealed and stored at 25°C, and the ethylene concentration and oxygen concentration were measured immediately after enclosing, on the 4th day, and on the 8th day. The results are shown in Tables 3 and 4.

As is clear from the results in Tables 3 and 4 above, it is clear that the gel-immobilized microorganisms have sufficient ethylene assimilation ability and can be used as a freshness-preserving agent.

Next, a similar experiment using a microbial extract (cell-free system) will be described.

Experiment 3 The same microorganisms (net 10 g) as in Experiment 1 were suspended in 50 ml of O, IM phosphoryl buffer (PH 6, 84), subjected to ultrasonic treatment (IOKH 2, 120 ml), and the resulting centrifuged supernatant was Furthermore, sterile filter and extract 10ml.
was permeated into a glass filter (11Φ opening), and stored in the same manner as in House 1, and the concentrations of ethylene, oxygen, and carbon dioxide in the packaging material were measured over time. As a countermeasure, 0.1
A glass filter in which only M phosphate buffer was permeated was used. The results are shown in Table 5.

Table 5 [ ! As can be seen from the results shown in the table above, it can be seen that cell-free systems (extracts of microorganisms) have the same effects as microorganisms.

Finally, the relationship between the microorganism or extract having ethylene decomposition ability or ethylene assimilation ability used in the present invention and its water content will be clarified through experiments.

Experiment 4 Mycobacterium flei (FIycobacter
RumphIei) :Experiment with IFON113L60
After culturing in the same manner as above, add 0.1M phosphate buffer (Ptl 6
．． E? ) to obtain washed microorganisms, and after freeze-drying, 1
Weighed 00 mg and 200 mg, and the water content was 0.4.
Add 0.1M phosphate buffer (pH 6,8) to give a concentration of 0.60.7o, 8o, and 99%, mix well, and adsorb it on a glass wool cap (thickness 0.45 x 95 cTA). Made of polypropylene (thickness 0.11mm, 30cm)
x 15 cm), fill with 2'OO+n6 sterile air containing 50 ppm ethylene gas, seal and store at 25°C.
Saved with. Ethylene concentration, oxygen concentration, and carbon dioxide concentration were measured immediately after encapsulation, on the second day, and on the sixth day. The results are shown in Tables 6, 7, and 8.

Table 6 Ethylene concentration Table 7 Oxygen concentration Table 8 Carbon dioxide concentration As is clear from Tables 6, 7, and 8, the concentrations of ethylene, oxygen, and carbon dioxide are as follows:
% or more, significant changes were observed. As is clear from this experimental fact, it can be understood that in order to utilize microorganisms as a freshness-preserving agent, it is desirable that the moisture content be approximately 70% or more.

(Example) Example 1 The same medium 11 as shown in the experimental example was placed in a 21-volume Erlenmeyer flask, and cultured with stirring at 27° C. for 3 days while aerating air containing 300 ppm ethylene.

Then, it was centrifuged to obtain 3 g of microorganisms (wet).

1 g of this microorganism (wet) was adsorbed onto a glass wool filter paper (FJ Mi 0.45 mm x 95 cnl) and one banana (approx.
Put it in a polyethylene L/7 bag (thickness 0.08 mm),
It was sealed and stored at 25°C. Three weeks later, the ethylene concentration and oxygen concentration were measured, and at the same time, the hardness of the bananas was measured using a texturometer, and the color tone and freshness were sensory evaluated. The results are shown in Table 9.

Note that the texturometer measurement is performed on sliced bananas with the skin removed, and is expressed in one texturometer unit.The higher the value, the harder the banana is, that is, the slower the ripening. In addition, color tone and freshness were evaluated on a five-point scale. That is, the freshness of the fruit was divided into 5 grades, with 5 indicating that the fruit was very fresh and hard, and 1 indicating that the fruit was very aged and crab-like. In addition, the color tone is determined based on the color of the skin, and those that remain green are ranked as 5.
It was divided into 5 grades, with those that turned black being rated 1.

The panel test was evaluated by 10 people and the average value was shown. For comparison, one commercially available activated carbon and one potassium permanganate-based ethylene absorbent were each tested in the same manner.

Table 9 Also, the control in Table 9 does not use any microorganisms or commercially available freshness preserving agents as in the present invention, but simply
It is simply a filter paper impregnated with 0.1M phosphate buffer (PH6,8).

From the results shown in Table 9, it can be seen that the method according to the present invention exhibits a superior effect not only in comparison with the control method but also in comparison with the commercially available ethylene absorbent and extends the shelf life of bananas. I can understand that it is possible.

Example 2 The same microorganisms as shown in the banana example were used. 3 g of this microorganism (wet) was transferred to glass wool filter paper (
Thickness 0.45 dragon x 95 c JA) Polypropylene bag containing 5 peaches (30 x 45 cm)
, thickness 0.11 mm) and stored at 25°C. Furthermore, the peaches were prevented from coming into direct contact with microorganisms.

In addition, for comparison, commercially available potassium permanganate-based preservatives and activated carbon-based preservatives, and as a control, filter paper impregnated with water were each subjected to the same test. After 8 days of storage, the ethylene concentration and oxygen concentration were measured, and the freshness of the peaches was sensory evaluated. In addition, the freshness of the products according to the present invention did not deteriorate significantly even after storage for up to 20 days, but the products using other commercially available freshness-preserving agents and the control products all suffered from spoilage and did not last long. In terms of storage performance, it was far inferior to that of the present invention. These results are shown in Table 1O.

Table 10: The color tone is determined based on the color of the skin, and the color that remains green is 5.
The samples were classified into 5 grades, with those that were browned being ranked as 1. Also,
The freshness was divided into 5 grades, with 5 being very fresh and hard with the skin removed, and 1 being extremely overcooked and crab-like.

Each 5-level evaluation was performed by 10 panelists, and the average value is shown. Furthermore, Table 11 shows the increase in the number of spoiled pieces in each test plot as a percentage (%).

As is clear from the results shown in this table, the product according to the present invention has a spoilage rate of 0 after 7 days of storage.
%, whereas with commercially available products and -kisho products, spoilage has already progressed to around 10-20% after 4 days of storage, and after 7 days the spoilage rate is 30-50%. However, after 10 days of storage, the method according to the present invention shows only about 10% decomposition, while the other methods have progressed to about 80 to 90% decomposition. It was confirmed that this method of preserving freshness is effective.

Table 11! [(Effects of the Invention) Since the present invention is configured as described above, it has the following advantages.

(11?rk organisms or their extracts reduce ethylene and oxygen concentrations and increase carbon dioxide concentrations at the same time, so it is easy to use and only requires the use of one type of freshness-preserving agent.
By selecting the type of microorganism, the degree of oxygen and carbon dioxide removal can be freely selected.

(2) High humidity inside packaging materials for fruits, vegetables, and flowers not only does not affect the ability of microorganisms to decompose ethylene;
Favorable for enzymatic reactions.

(3) Since the microorganisms or their extracts used in the present invention are organic substances, they can be disposed of together with ordinary combustible garbage.

(4) Furthermore, since the microorganisms or their extracts used in the present invention do not contain any heavy metals, strong acids, or poisonous substances, there is no risk of elution and they can be used safely.

(5) It is significantly superior to conventional freshness-preserving materials in terms of freshness, taste, and color of fruits and vegetables, and is harmless and hygienic.

(6) In particular, in the case of an extract (extract liquid), it is also possible to apply it directly to fruits, vegetables, and flowers by spraying or the like.

Claims (1)

[Claims] 1. A method for preserving the freshness of fruits, vegetables, and flowers for a long period of time, the method comprising allowing a microorganism capable of decomposing or assimilating ethylene or an extract thereof to coexist with the fruits, vegetables, and flowers in the same package.