JP2001095480A - Method for preserving spinach - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preserving spinach packages having MA effects and capable of extending a shelf life and easily fixing a condition. SOLUTION: This method for preserving spinach is to preserve spinach in a spinach package at a temperature for satisfying 0<T<=25 and equation 1:17.763lnP-70.001<=T<=8.125lnP+0.2407, where P is the amount of oxygen permeation (cc/g/day/atm) and T ( deg.C) is the preservation temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an MA (Modified)
The present invention relates to a package for keeping freshness of spinach by Atmosphere.

[0002]

2. Description of the Related Art Spinach is often sold in units of 200 to 300 g, and is bundled with a string or put in a polypropylene bag having an open top. Work such as individual wrapping is generally performed in the production area, and they are transported in cardboard boxes. Efforts are being made to maintain the quality of fruits and vegetables at the production area and at the distribution stage, such as by using pre-cooling, insulated trucks, and refrigerated trucks, but the construction of cold chain systems in Japan is lagging behind in the United States and other countries. At present, quality deterioration after harvest is inevitable. Spinach has a large amount of respiration and active transpiration, so it is very easy to wither and is ideally stored at low temperature and high humidity. Spinach display at retail stores is sometimes seen in refrigerated cases, but it is still prone to wilting and is often sold on shelves at room temperature. At the store, every few hours at room temperature, water is applied to the withered spinach to revive it, and efforts are made to make it last a little longer. However, spinach is basically sold out on the day. As described above, spinach has a large respiratory volume, is liable to undergo deterioration such as withering, yellowing, and the like, and has a large decrease in quality during distribution and sale. Especially when the temperature rises in summer or when long-distance transportation is required, it often becomes a problem when the market or retail store arrives. Therefore, in production areas, market participants, retail stores, and the like, there is a demand for a technique for maintaining freshness immediately after harvesting spinach until it is sold. However, such a method has not been found yet.

[0003] It is generally known that the lower the temperature, the lower the respiratory volume and the longer the shelf life of fruits and vegetables within the range where freezing and low-temperature damage do not occur, but the surrounding gas atmosphere has a lower oxygen concentration than the atmosphere. , Even in the case of high carbon dioxide concentration, the amount of respiration is reduced and energy consumption is suppressed,
Deterioration, ripening, etc. are suppressed and freshness is maintained. CA (Contrrolled Atmosphere) storage uses the characteristics of this plant. In CA storage, in addition to low-temperature management, artificially flowing gas into the storage room where fruits and vegetables are put, and keeping the gas composition in the storage at the most suitable low oxygen and high carbon dioxide conditions for the fruits and vegetables to maintain the freshness of the fruits and vegetables Do. In the case of spinach, the shelf life in CA storage (0 ° C., 10% oxygen, 10% carbon dioxide) is about 3 weeks. However, the introduction thereof requires enormous equipment costs and must be kept in a refrigerator, and quality control of spinach after delivery, that is, during distribution and during sale, cannot be performed at all. Also, it is difficult to accurately maintain the temperature at 0 ° C., and spinach may freeze. As described above, spinach is easily damaged, and a method for maintaining freshness such as this has not been developed. Therefore, a technique for maintaining freshness that is practical in both aspects of maintaining freshness during distribution and improving storage properties is expected.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to cause spinach yellowing, wilting, and decay without causing atelectasis, which is a cause of ethanol and acetaldehyde, which is accompanied by a bad smell and adversely affects spinach itself. An object of the present invention is to provide a freshness maintaining package for spinach having an MA effect capable of preventing the occurrence of odor.

[0005]

The mechanism for maintaining the freshness of fruits and vegetables in the MA packaging is similar to the above-mentioned CA storage, by setting the environment around the fruits and vegetables to a state of lower oxygen and higher carbon dioxide than the atmosphere. is there. However, in CA storage, a large-scale device is used to adjust the gas composition in the warehouse.
In the A package, the carbon dioxide discharged by the respiration of the packaged fruits and vegetables is appropriately left in the package, and the oxygen in the package, which is also consumed by the respiration of the fruits and vegetables, is taken in from the outside of the package in an appropriate amount to reduce oxygen. A high carbon dioxide state is created. In other words, the atmosphere in the packaging bag, that is, the gas atmosphere around the fruits and vegetables, is adjusted according to the balance between the amount of fruits and vegetables breathing and the amount of gas permeation of the package (the amount of gas transferred from the inside of the packaging bag to the atmosphere, or from the atmosphere to the package). Will do. The present invention incorporates the above-mentioned concept of MA. In a spinach package, when the oxygen permeation amount of the package is P (cc / g / day / atm) and the storage temperature is T (° C.), 0 <T ≦ 25 and 17.763 lnP−70.001 ≦ T ≦ 8.125 lnP + 0.2407 (Formula 1) Preferably, a temperature T satisfying 0 <T ≦ 25 and 17.321 lnP−60.621 ≦ T ≦ 17.172 lnP−45.706 (Formula 2) (° C). (Where lnP represents the natural logarithm of P.) Preferably, the oxygen concentration in the package is 10 to 19%,
Carbon dioxide concentration of 1 to 10%, more preferably oxygen 1
It is a package of spinach containing 5 to 18% and carbon dioxide of 2 to 6%. Also, in the present invention, the package may have a hole diameter of 1 part.
This is a method for storing spinach made of a synthetic resin film having fine pores of 0 to 300 μm or less or scratches on the surface. If the gas permeation amount of the packaging bag is not insufficient, it is not necessary to process the film with fine holes, scratches, etc., but this is almost impossible with the current actual distribution. In the actual distribution of fruits and vegetables, it is easily assumed that the temperature rises and falls. Therefore, the condition of equation (2) is more preferable for safety.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Spinach is prone to yellowing, withering and decay, and has a short shelf life at 25 ° C. of about one day.
The limit is 3 to 4 days even at 10 ° C. Although it has become common practice to perform pre-harvest pre-cooling in production areas, it is impractical to control the temperature of spinach to 10 ° C or less during distribution and sales, and the quality of spinach after shipment is rapidly increasing. Has been impaired.

Accordingly, the present inventors have developed a spinach MA package to suppress the deterioration of spinach. As a result, it has been found that if spinach is wrapped in a package that satisfies the condition of the above formula (1), it is possible to extend the shelf life more than before. Specifically, the packaging that satisfies the condition of the above formula (1) suppresses spinach yellowing, wilting, and decay, and has a longer shelf life of about 10 days at 0 ° C. (durability in air) than conventional (in air). Can be extended for 3 to 6 days at 10 ° C (about 5 to 6 days in air) and about 2 days at 25 ° C (about 1 to 2 days for atmospheric durability). did it.
In addition to preventing quality deterioration during distribution and sale, the packaging bag of the present invention can be stored at a low temperature for about one month for shipping adjustment.

[0008] Fruits and vegetables generally perform atelectasis under excessively low oxygen and high carbon dioxide conditions to generate alcohol and acetaldehyde. Spinach also causes the same phenomenon without leaking to this example. Conversely, if the gas atmosphere is too close to the atmosphere, the respiratory volume will not be suppressed and freshness will not be maintained. Therefore, when keeping freshness of fruits and vegetables in MA,
The gas atmosphere must be in the middle zone between the two. In other words, under the condition of 17.763 lnP-70.001> T, respiratory disorder occurs in spinach and the quality is remarkably reduced. When T> 8.125 lnP + 0.2407, the oxygen concentration in the package does not decrease so much, and respiratory depression is insufficient. And the effect of inhibiting spinach yellowing and decay is reduced. When maintaining freshness of spinach in the MA packaging, the gas composition conditions are preferably such that the oxygen concentration is 10 to 19;
%, The carbon dioxide concentration is 1 to 10%, more preferably the oxygen concentration is 15 to 18%, and the carbon dioxide concentration is 2 to 6%.
If it is difficult to predict the ambient temperature during actual distribution, the package is anaerobic or the oxygen is 15% to 18% and the carbon dioxide is 2% to 6% in view of safety in order to prevent oxygen from becoming higher than 19%.
Good packaging design. This condition can be obtained by using a package that satisfies the above formulas (1) and (2).

[0009] Spinach has a risk of freezing when the temperature is lower than 0 ° C. Further, even at a temperature higher than 25 ° C., the use of the package of the present invention could maintain the quality slightly better than the conventional condition, but the rot of spinach occurred in about 1 to 2 days, and the freshness was deemed to be practical. No retention effect was obtained. Therefore, the temperature T (° C.) when the package of the present invention is used.
Is 0 <T ≦ 25. However, using the package of the present invention, even if the temperature may exceed 25 ° C. for about half a day during distribution, sale, etc., the respiration of the fruits and vegetables does not change unless the temperature of the fruits and vegetables themselves rises, Since the inside of the package does not immediately become anaerobic, there is no particular problem if it is kept at 25 ° C. or less thereafter.

[0010] The material of the package used in the present invention is not particularly limited as long as it can be used for packaging of fruits and vegetables. In general, unstretched polypropylene, stretched polypropylene, polyethylene, polystyrene, polyvinyl chloride and the like are used. Can be In addition, other polyamides, polyesters, films of polycarbonate and the like, and further may be composite films of these, and even those provided with a sealant layer on the surface of these films, are films which have been subjected to antifogging treatment. Is also good. The thickness of these films is preferably 20 to 60 μm. Further, these films may be transparent or may have a printed surface. If these materials were used as they were as a package, it would not be possible to obtain oxygen permeation satisfying the above condition, so it was necessary to impart oxygen permeability to the film used in order to increase the oxygen permeation of the package. There is. Any method of adjusting the amount of oxygen permeation of the package may be used. To give a specific example, the package can be adjusted to a gas permeation amount necessary for storing spinach by forming micropores having an average pore diameter of 10 to 300 μm in the film. Regarding the above micropores,
If the average pore size is less than 10 μm, processing is difficult, and if it exceeds 300 μm, the number of holes per pack decreases, and it becomes difficult to adjust the gas composition in the bag. Therefore, an average pore diameter of 10 to 300 μm is preferable in terms of balance. Depending on the amount of spinach to be wrapped or the temperature zone in which it is stored, the amount of oxygen permeation required for the wrapped body is reduced. In this case, the average pore size is preferably 10 to 100 μm.
Further, the amount of gas permeation can be adjusted by scratching the film surface. In these cases, the oxygen permeability of the package is
The sum of the amount of oxygen permeated by the material itself and the amount of oxygen permeated by the size and number of the micropores or the size, depth and number of scratches.

The package used in the present invention needs to be sealed in order to obtain the MA effect. When the bag is used, the sealing method may be any method such as heat sealing, tying band, rubber band, caulking, back sealer, zipper bag and the like. The packaging form is not limited to bags, but may be, for example, a tray container with a top seal.
The tapper may be processed so as to satisfy the condition of the above formula (1). Further, it can be used as an MA cardboard box in which the packaging bag of the present invention is integrated with the cardboard box. The purpose of use of the present invention is not limited to keeping freshness during distribution and retailing, but also long-term storage at low temperatures.

Hereinafter, the present invention will be described with reference to examples.

[Example] << Example 1 >> size, length 200mm, width 400
mm, micropores (average pore diameter 80 μm, 14 holes) were opened so that the oxygen permeation amount became 14.0 cc / 24 h · atm · gr, 30
Approximately 200 gr of spinach was packed in a bag of μm antifogging stretched polypropylene (antifogging OPP), sealed, and stored at 2 ° C. for 25 days. Table 1 shows the results of the quality evaluation of the spinach at that time. n = 4, and the same number was used for evaluation. (If P is 14.0, according to equation 1, 0 <
T ≦ 21.7. << Example 2 >> 30 μm anti-fog with a size of 200 mm in length and 400 mm in width, and micropores (average pore diameter 80 μm, 20 pieces) were opened so that the oxygen permeation amount was 19.5 cc / 24 h · atm · gr. About 200 gr of spinach was packed in a bag made of stretched polypropylene (anti-fogging OPP), sealed, and stored at 10 ° C. for 15 days. Table 1 shows the results of the quality evaluation of the spinach at that time. n = 4, and the same number was used for evaluation. (If P is 19.5, according to equation 1, 0 <T ≦ 2
4.4. << Example 3 >> 30 μm anti-fog with a size of 200 mm in length and 400 mm in width, and micropores (average pore diameter 100 μm, 46 pieces) were opened so that the oxygen permeation amount was 71.2 cc / 24 h · atm · gr. About 200 gr of spinach was packed in a bag made of stretched polypropylene (anti-fogging OPP), sealed, and stored at 20 ° C. for 7 days. Table 1 shows the results of the quality evaluation of the spinach at that time. n = 4, and the same number was used for evaluation. (If P is 71.2, according to equation 1, 5.6 ≦ T ≦
25. << Example 4 >> 30 μm anti-fog having a size of 200 mm in length and 400 mm in width and having micropores (average pore diameter 100 μm, 61 pieces) opened so that the oxygen permeation amount is 94.0 cc / 24 h · atm · gr. About 200 gr of spinach was packed in a bag made of stretched polypropylene (anti-fogging OPP), sealed, and stored at 25 ° C. for 5 days. Table 1 shows the results of the quality evaluation of the spinach at that time. n = 4, and the same number was used for evaluation. (If P is 94.0, according to equation 1, 10.7 ≦ T
≦ 25. )

Comparative Example 1 Size, length 200 mm, width 40
0 mm, and the oxygen permeation amount is 1.0 cc / 24h · atm · gr.
A bag made of 30 μm antifogging stretched polypropylene (antifogging OPP) is filled with about 200 gr of spinach and sealed.
Stored at 25 ° C for 25 days. Table 2 shows the results of the quality evaluation of the spinach at that time. n = 4, and the same number was used for evaluation. (If P is 1.0, according to Equation 1, 0
<T ≦ 0.2. << Comparative Example 2 >> The bag used had an oxygen permeability of 69.6 cc / 24.
Micropores (average pore diameter 100 μm, 4
Spinach was stored for 25 days in the same manner as in Example 1 except that 5) were opened. Table 2 shows the results of the quality evaluation of the spinach at that time. (If P is 100.1, then according to equation 1, 5.4 ≦ T ≦ 25.) << Comparative Example 3 >> The oxygen permeation amount of the bag used is 2.9 cc / 24h.
・ Micropores (average pore diameter 80μm, 2 pieces) so that atm ・ gr
Spinach was preserved for 15 days in the same manner as in Example 2 except that was opened. Table 2 shows the results of the quality evaluation of the spinach at that time. (If P is 2.9, according to equation 1, 0 <
T ≦ 8.8. << Comparative Example 4 >> The bag used had an oxygen permeability of 100.1 cc /
Micropores (average pore diameter 100μm, 24h ・ atm ・ gr)
Spinach was stored for 15 days in the same manner as in Example 2 except that 65 pieces were opened. Table 2 shows the results of the quality evaluation of the spinach at that time. (If P is 100.1, Equation 1
According to this, 11.8 ≦ T ≦ 25. << Comparative Example 5 >> The bag used had an oxygen permeability of 6.6 cc / 24h.
・ Small pores so that it becomes atm ・ gr (average pore diameter 80μm, 6 pieces)
The spinach was stored for 7 days in the same manner as in Example 3 except that was opened. Table 2 shows the results of the quality evaluation of the spinach at that time. (If P is 6.6, according to equation 1, 0 <T
≤ 15.5. << Comparative Example 6 >> The bag used had an oxygen transmission rate of 255.2 cc /
Micropores (average pore size 150μm, 24h ・ atm ・ gr)
Spinach was stored for 7 days in the same manner as in Example 3 except that 74 pieces were opened. Table 2 shows the results of the quality evaluation of the spinach at that time. (When P is 255.2, T> 25 according to equation 1.) << Comparative Example 7 >> The bag used had an oxygen transmission rate of 12.1 cc / 24.
micropores (average pore diameter 80 μm, 12
5), except that spinach was opened in the same manner as in Example 4.
Saved for days. Table 2 shows the results of the quality evaluation of the spinach at that time. (When P is 12.1, 0 <T ≦ 20.5 according to equation 1.) << Comparative Example 8 >> The bag used had an oxygen transmission rate of 275.8 cc /.
Micropores (average pore size 150μm, 24h ・ atm ・ gr)
Spinach was stored for 5 days in the same manner as in Example 4 except that 80 pieces were opened. Table 2 shows the results of the quality evaluation of the spinach at that time. (When P is 275.8, T> 25 according to the formula 1.) <Comparative Example 9> Spinach was prepared in the same manner as in Example 2 except that four holes having a diameter of 5 mm were formed in the used bag. Saved for days. Table 2 shows the results of the quality evaluation of the spinach at that time.

The symbols in the table are as follows. ○: fresh, □: slight change, Δ: limit of commercial properties, ×: unsuitable for edible use (△ × is between △ and ×) The expression of odor in the table is as follows. Alcohol odor generation

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

According to the preservation method of the present invention, spinach of stable quality can be supplied by a package having an MA effect in which conditions can be easily set, and wilting, yellowing, putrefaction and off-flavor are generated. By preventing such a situation, the shelf life after that can be extended.

Claims (4)

[Claims] 1. In a spinach package, the oxygen permeation amount of the package is P (cc / g / day / atm), and the storage temperature is T.
A method for storing spinach, characterized by storing at a temperature T (° C.) satisfying 0 <T ≦ 25 and 17.763 lnP−70.001 ≦ T ≦ 8.125 lnP + 0.2407 (formula 1), where (° C.). 2. The method for storing spinach according to claim 1, wherein the oxygen concentration in the package is 10 to 19% and the carbon dioxide concentration is 1 to 10%. 3. The method for storing spinach according to claim 1, wherein the package comprises a film having fine pores having a pore size of 10 to 300 μm or less. 4. The method for preserving spinach according to claim 1, wherein the package comprises a film having a surface provided on the surface to enhance oxygen permeability.