JPH1149248A - Method for holding quality of cut lettuce - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for suppressing the deterioration of quality and deterioration such as soddenness or the like caused by browning and offensive smell (alcohol smell) generated when cut lettuce is packed. SOLUTION: In this method for preserving the quality of cut lettuce, a packing bag made of a plastic film is packed with cut lettuce from the opening part of the bag and, subsequently, the opening part is hermetically sealed in a low pressure state to regulate the amt. of air in the packing bag. This low pressure state is regulated by a vacuum packer and set to 600-400 mmHg by the gauge meter of the vacuum packer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for maintaining the quality of cut lettuce, and more particularly, to a method for reducing the quality deterioration and deterioration caused by browning and off-flavor (alcohol smell) generated when packaging cut lettuce. The present invention relates to a method for maintaining the quality of cut lettuce to be suppressed.

[0002]

2. Description of the Related Art Conventionally, raw vegetables are washed with water immediately before eating.
Although it was cut to an appropriate size and eaten, in recent years, due to changes in the living environment, in consideration of the convenience of consumers, it has been cut in advance to an appropriate size so that raw vegetables can be eaten as it is. A packaged product obtained by filling and packing it in a plastic packaging bag or the like is sold at a supermarket or the like. A typical example is a packaged product in which cut lettuce is filled and packaged. In this case, it is extremely important to maintain the freshness of the packaged product and to suppress the deterioration in quality. By the way, in general, as a method for suppressing the deterioration of the quality of cut vegetables, usually, the gas composition in the packaging bag is maintained at a low oxygen and high carbon dioxide concentration by utilizing the respiration of the contents.
(Modified Atmosphere) packaging method is used. Therefore, when the cut vegetables are packaged by the MA packaging method to maintain the quality, the respiratory volume of the cut vegetables after the cut is usually higher than the respiratory volume of the vegetables before the cut, and the quality deterioration rate Also tend to be faster,
The packaging bag is subjected to micropore processing and the like to adjust the oxygen permeability and suppress the deterioration of cut vegetables such as yellowing and browning. In the most typical cut lettuce packaging, the cause of browning is that polyphenols present in a living body are oxidized by an enzyme (polyphenol oxidase) to produce a brown polymer. From being expressed,
The gas replacement packaging method, the vacuum packaging method and the like are frequently used. As described above, usually, the quality maintenance of cut vegetables, as well as the freshness maintenance of agricultural products, by adjusting the oxygen permeability according to the respiratory volume after cutting using respiratory action, yellowing, browning It suppresses the generation of off-flavors and odors.

[0003]

However, in the packaging of cut lettuce described above, in order to suppress browning and the like,
Vacuum packaging is effective, but under vacuum packaging, alcohol odor tends to be generated by anaerobic respiration, and this turtle causes sensual deterioration. There is a problem in that the portion that is in contact with the bag is likely to be dislodged due to moisture or the like flowing out from the cut. Further, in the packaging of cut lettuce, in order to suppress the anaerobic respiration of cut lettuce, when sealed packaging with aeration, it depends on the filling amount, but especially in the case of a small amount of 100 to 200 g,
There is also a problem that browning easily occurs due to a large influence of oxygen in the residual air. Accordingly, an object of the present invention is to provide a method for maintaining the quality of cut lettuce which suppresses the deterioration of quality due to browning and unpleasant odor (alcohol odor) generated when the cut lettuce is packaged.

[0004]

Means for Solving the Problems The present inventor has conducted intensive studies to solve the above problems, and as a result, after filling cut lettuce in a plastic film packaging bag, when sealing the opening thereof, Using a vacuum packaging machine,
By adjusting the internal pressure to a moderately low pressure state, adjusting the amount of residual air in the packaging bag to an appropriate amount, and sealingly packaging,
The present invention has found a method for maintaining the quality of cut lettuce, which can suppress browning and off-flavor (alcohol odor) of the cut of the cut lettuce, thereby extending the shelf life of the cut lettuce. Is completed.

That is, according to the present invention, a plastic film packaging bag is filled with cut lettuce from its opening, and then the opening is sealed under low pressure to reduce the amount of air in the packaging bag. The present invention relates to a method for maintaining the quality of cut lettuce characterized by adjusting, and furthermore, the present invention relates to the quality maintaining method, wherein the low pressure state is adjusted by using a vacuum packaging machine. The present invention also relates to a method for maintaining the quality of lettuce, and the present invention further provides a method for maintaining the quality of cut lettuce, wherein the low pressure state is 600 mmHg or more by a gauge of a vacuum packaging machine.
The present invention relates to a method for maintaining the quality of cut lettuce, which is characterized by being in the range of 400 mmHg. In the above,
The low pressure state is indicated by an absolute value representing a value obtained by reducing the pressure. In the present invention, when the normal pressure is 760 mmHg, the value indicated by the gage meter is expressed as an absolute value. Therefore, when the gage meter is 500 mmHg, the inside of the chamber is 26 mm.
It becomes 0 mmHg.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The above-mentioned present invention will be described in more detail below with reference to embodiments of the present invention. First,
In the present invention, the plastic film constituting the plastic film packaging bag will be described. As such a plastic film, for example, when the form of the packaging bag is various bags made by thermal bonding, it is used for this. As a plastic film, a heat seal is used for bag making and sealing of the opening, etc.
It is necessary to have heat sealability (thermal adhesion). Further, in the present invention, as the above-mentioned plastic film, a packaging bag is constituted, and contents (cut lettuce) are formed.
It is also necessary to have various physical properties such as strength, heat resistance, durability, etc. that can be filled and packaged. In the present invention, examples of the plastic film having the above properties include low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear (linear).
Low-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer,
Ethylene-acrylic acid or methacrylic acid copolymer, methylpentene polymer, polybutene resin, polyvinyl chloride resin, polyvinyl acetate resin, polyvinylidene chloride resin, vinyl chloride-vinylidene chloride copolymer, poly (meth Acrylic resin, polyacrylonitrile resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyester resin, polyamide resin, polycarbonate -Bone resin,
Films or sheets of known resins such as polyvinyl alcohol-based resins, saponified ethylene-vinyl acetate copolymers, fluorine-based resins, diene-based resins, polyacetal-based resins, polyurethane-based resins, nitrocellulose, etc. -Can be arbitrarily selected and used. In the present invention, the above-mentioned resin film or sheet may be used in an unstretched state or in a uniaxially or biaxially stretched state. The thickness is arbitrary, but is in the range of about several μm to 300 μm,
Preferably, it can be used by selecting from about 15 μm to 200 μm.

In the present invention, among the resin films or sheets as described above, the resin film or sheet itself is used as a heat sink.
When it has thermal adhesiveness such as sealability, it can be used as a single film or sheet, and when it does not itself have thermal adhesiveness such as heat sealability. Is
It can be used by laminating it with a resin film or sheet having heat adhesive properties such as heat sealability. In the present invention, for example, polyester resin, polyamide resin, polyaramid resin, polyethylene resin, polypropylene resin, polycarbonate resin, acrylic resin, polyacetal resin, fluorine resin, etc. Examples of the tough resin film or sheet include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, and ethylene-
Acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, acid-modified polyolefin resin It is preferable to laminate and use a resin film or sheet which can be fused. In the above, the thickness of the laminated film can be selected from several μm to 300 μm, preferably about 15 μm to 200 μm. In the present invention, it goes without saying that the laminated film is perforated in the layer thickness direction.

In the present invention, the plastic film may be, for example, a stretched polypropylene film, a non-stretched polypropylene film, a polystyrene film, a polyethylene film, or a stretched polypropylene film in view of bag-making conditions, production cost, and other factors. It is preferable to use a laminated film obtained by laminating a polyolefin resin such as a polypropylene resin or a low-density polyethylene resin into a film by extrusion coating or the like, a laminated film obtained by laminating a polyethylene film by a dry lamination method, or the like.

Next, in the present invention, a method of manufacturing a packaging bag by making a bag using the resin film or sheet as described above will be described.
There are various methods. A resin film or sheet as described above is used, the heat-sealing surfaces are superposed on each other, and the peripheral end is heat-sealed. Then, the sealing portion is provided, and the packaging bag for tomato according to the present invention can be manufactured. In the above, as the form of heat sealing the peripheral end, for example, side seal type, two-way seal type, three-way seal type, four-way seal type, envelope-attached seal type , Gassho pasted seal type (pyro-sealed type), pleated seal
Heat-sealed forms such as seal type, flat-bottom seal type, square-bottom seal type, boat-bottom seal type, etc. can do. Others, for example, self-supporting packaging bags (standing pouches)
Etc. can also be manufactured. In the above, the method of heat sealing includes, for example, a bar seal, a rotary roll, and the like.
It can be carried out by a known method such as a seal, a belt seal, an impulse seal, a high frequency seal, an ultrasonic seal and the like.

[0010] Next, in the present invention, a predetermined amount of cut lettuce is filled from the opening into the packaging bag formed from the plastic film as described above, and then the opening is formed under low pressure. And by adjusting the amount of air in the packaging bag, a packaged product filled with cut lettuce can be manufactured. In the above-mentioned present invention, the low pressure state is, specifically, adjusted by using a vacuum packaging machine. Further, the low pressure state is controlled by a gauge of the vacuum packaging machine from 600 mmHg to 400 mm.
It is preferable to adjust in the range of Hg. That is, in the present invention, a predetermined amount of cut lettuce is filled in a plastic film packaging bag, and then the low pressure state in the chamber of the vacuum packaging machine is reduced to 400 m by a vacuum gauge.
mHg to 600 mmHg, more preferably 450
It is set at about mmHg to 500 mmHg, and under such a low pressure condition, the opening is sealed and the amount of air in the packaging bag is adjusted to produce a packaged product filled with cut lettuce. is there. In the above, when the gage meter is less than 400 mmHg, deaeration in the bag becomes insufficient, and the amount of remaining air increases, so that the cut end of the cut lettuce is apt to brown. On the other hand, if the pressure exceeds 600 mmHg, the amount of residual air in the sealed package becomes extremely small, so that the breath of cut lettuce becomes an anaerobic breath, and an alcohol odor is generated. , With the resulting sensual deterioration, furthermore, due to the moisture generated in the bag,
This is not preferable because it has a problem in that the leaf tip of the cut lettuce that comes into contact with the bag has a problem.

In the above description, the vacuum packaging machine is not particularly limited as long as the degree of vacuum can be adjusted by any method, and the amount of air remaining in the packaging bag can be adjusted. Any one is possible if possible. Specifically, as vacuum packaging machines, small and medium-sized vacuum packaging machines currently used as vacuum packaging machines, interlocking vacuum packaging machines, vertical bagging vacuum packaging machines, rotary vacuum packaging machines, vacuum A contact packaging machine, a deep drawing vacuum packaging machine, etc. can be used. Furthermore, in the above, as cut lettuce, lettuce is washed sufficiently with water and cut into an appropriate size suitable for eating it, or, further,
Cabbage, carrot, and other raw vegetables can be cut to an appropriate size, and a mixture of the cut vegetables with the cut lettuce described above, or the like can be used.

Thus, in the present invention, the cut lettuce-filled packaged product manufactured as described above is cut and sealed by adjusting the amount of air remaining in the bag to an appropriate amount and sealingly packaging. It is possible to suppress the occurrence of browning and off-flavor (alcohol smell) of the cut portion of the lettuce, thereby extending the quality storage period.

[0013]

Next, the present invention will be described more specifically with reference to examples. Example 1 Using a heat-sealed stretched polypropylene film having a thickness of 30 μm, a pillow-type packaging bag having a raw fabric size of 420 × 250 mm and a bag size of 200 × 250 mm was manufactured. Next, the lettuce is divided into four parts, and the cut lettuce is divided into 1
The pyro-type packaging bag prepared above was filled at a rate of 50 g / bag through the opening, and then the opening was heat-sealed to produce a filled product. At the time of the above sealing, the package was hermetically sealed under the following reduced pressure using a vacuum packaging machine. (1), 450 mmHg reduced pressure (2), 500 mmHg reduced pressure (3), 550 mmHg reduced pressure (4), 600 mmHg reduced pressure (5), air-tight sealed packaging (6), 300 mmHg reduced pressure (7), 700 mmHg reduced pressure After storing the filled product at 10 ° C. for up to 5 days, its appearance and sensory change were measured.
The above measurement results are shown in Table 1 below.

[0014]

[Table 1]

Example 2 On one side of a stretched polypropylene film having a thickness of 30 μm,
After coating the urethane-based coating agent, a linear low-density polyethylene having a thickness of 3
The film was extruded to form a film having a thickness of 0 μm to produce a laminated material comprising a stretched polypropylene film having a thickness of 30 μm / anchor coat layer / a linear low-density polyethylene layer having a thickness of 30 μm.
Next, using the laminated material produced above, a bag size of 300
× 400 mm pillow-type packaging bags were produced. Next, the lettuce is divided into four parts, and the cut lettuce is divided into 1 kg / bag at a rate of 1 kg / bag in the above-prepared pillow-type packaging bag.
Filling was performed through the opening, and then the opening was heat-sealed to produce a filled product. At the time of the above sealing, the package was hermetically sealed under the following reduced pressure using a vacuum packaging machine. (1), reduced pressure of 450 mmHg (2), air-tight sealed packaging (3), reduced pressure of 700 mmHg Next, after storing the filled product produced above at 10 ° C. for up to 8 days, its appearance and sensory change were measured.
The above measurement results are shown in Table 2 below.

[0016]

[Table 2]

In Tables 1 and 2 above, the evaluation criteria indicated by numerals are as shown in Table 3 below.

[0018]

[Table 3]

As is evident from the results shown in Tables 1 and 2, all of (1) to (4) of Example 1 and (1) of Example 2 were obtained for 5 days or During the storage period of 8 days, browning of cut ends and generation of alcohol odor, which are indicators of quality deterioration of cut lettuce, were suppressed, and the quality retention was good. On the other hand, (5) and (6) of Example 1 and (2) of Example 2
In each case, the generation of alcohol odor was suppressed, but browning of the cut was observed from the second day of storage.
In the case of (7) and (3) in Example 2, browning of the cut was suppressed, but the alcohol odor was recognized from the second day, and the quality retention was not preferable.

[0020]

As is apparent from the above description, according to the present invention, when the cut lettuce is filled in a plastic film packaging bag and the opening is sealed, a vacuum packaging machine is used to seal the opening inside the chamber. Adjust the pressure to a moderate low pressure state,
By adjusting the amount of residual air in the packaging bag to an appropriate amount and performing hermetic packaging, it is possible to suppress browning of cut edges of cut lettuce and generation of an unusual odor (alcohol odor). The present invention relates to a method for preserving the quality of cut lettuce, which makes it possible to extend the quality storage period. That is, the present invention adjusts the amount of residual air in the package by filling the cut lettuce in the packaging bag and then sealingly packaging the package under low pressure, thereby providing the cut end of the cut lettuce with the enzyme. This suppresses the generation of alcohol odor due to browning and anaerobic respiration under a low oxygen concentration, and makes it possible to extend the quality retention period. Furthermore, in the present invention, in order to quickly and easily adjust the amount of residual air in the package, the package is hermetically sealed using a vacuum packaging machine, so that the operation is easy and It has the advantage of being simple. Further, in the present invention,
When filling and packaging cut lettuce, the residual air in the package must be
The quantity can be easily and easily adjusted by adjusting the internal pressure in the chamber of the vacuum packaging machine. Further, the quality can be maintained by filling and packaging under the optimal packaging conditions. It is assumed that.

Claims (3)

[Claims] 1. Filling a plastic film packaging bag with cut lettuce through its opening, and then sealing the opening under low pressure to adjust the amount of air in the packaging bag. A characteristic method of maintaining the quality of cut lettuce. 2. The method for maintaining the quality of cut lettuce according to claim 1, wherein the low pressure state is adjusted using a vacuum packaging machine. 3. The method for maintaining the quality of cut lettuce according to claim 1, wherein the low pressure state is in a range of 600 mmHg to 400 mmHg by a gauge of a vacuum packaging machine.