JPH0453887B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a plastic film that is used for food packaging and has excellent freshness-keeping effects, deodorizing effects, etc. (Conventional technology) In order to prevent spoilage and deterioration of freshness during food transportation and storage, fruits, vegetables, seafood, etc. have been frozen or refrigerated, dried, or directly treated with fungicides, such as with imported oranges. Various preservative and preservation methods are being used, such as spraying and vacuum storage in sealed storage and storage containers. (Problems to be solved by the invention) However, it has advantages and disadvantages in terms of food hygiene toxicity and equipment costs, so it is easy to implement and can be used on fruits, vegetables, and seafood. There is a need for the development of safe freshness-keeping, preservative, and preservation methods. (Means for Solving the Problems) As a result of various studies conducted by the present inventors in order to satisfy the requirements for food preservation, preservation, and freshness preservation, the present inventors found that iron() compounds are the main component,
This combined with L-ascorbic acid and/or citric acid is extremely active, and even if it is mixed and dispersed in a resin to form a film, it does not decompose and remains stable and maintains its activity. It has been discovered that by packaging and storing foods, the freshness of foods such as fruits and seafood does not decrease, and the foods can be kept fresh, lasted a long time, and have a preservative effect. The present invention has been made based on this knowledge. That is, the present invention provides a plastic characterized by containing a composition containing an iron () compound as a main component and an organic acid component (excluding ascorbic acids when used alone in stock) bound to this. It provides film. First, the composition (hereinafter simply referred to as iron() composition), which is composed of an iron() compound as a main component and has an organic acid component bonded thereto, used in the present invention will be described in detail. Examples of iron() compounds that are the main components of iron() compositions include ferrous sulfate, ferrous chloride, ferrous nitrate, ferrous bromide, ferrous iodide, and ferrous sulfate. In addition to iron () inorganic salts such as ammonium (Mohr's salt), iron () organic salts such as ferrous gallate, ferrous malate, and ferrous fumarate are included. The iron () compound is not limited to those exemplified above, and any compound can be used as long as it dissolves in water and forms divalent iron ions. In the present invention, "organic acid" is used in a broad sense. The organic acid component has the effect of stabilizing the active divalent iron ion by coordinating with the divalent iron ion of the iron() compound. Examples of such organic acids include ascorbic acids and carboxylic acids. Ascorbic acids herein refer to ascorbic acid, isoascorbic acid, alkali metal salts thereof, and include all of the D-form, L-form, and DL-form.
Particularly preferred is L-ascorbic acid. There are no particular restrictions on carboxylic acids, but oxyacids,
For example, citric acid such as citric acid, isocitric acid,
Lactic acid, tartaric acid, malic acid, etc. are used. Also, amino acids such as ethylenediaminetetraacetic acids,
4,5-diaminopyrimidines and the like are preferably used. In this iron() composition, an iron() compound is the main component. The ratio of iron () in the iron () compound to the organic acid component is preferably in the range of 1:0.02 to 0.30 (weight ratio), more preferably 1:0.02 to 0.13 when the organic acid component is ascorbic acid. Particularly preferred is a ratio of 1:0.05 to 0.13. In addition, when the organic acid component is a carboxylic acid such as citric acid, the ratio of iron () to the organic acid component is 1:0.01 ~
A range of 0.80 is preferable. Even if the organic acids are used in amounts exceeding the upper limit of the above-mentioned range, no increase in effectiveness can be expected and it becomes uneconomical, while below the lower limit, freshness preservation and deodorizing functions become insufficient. In the present invention, the organic acid components may be used alone or in combination of two or more. In particular, ascorbic acids should be used in combination with other organic acids. If used together,
A combination of ascorbic acid and citric acid is preferred;
At this time, since citric acid acts as an auxiliary stabilizer for ascorbic acid, its amount may be small. In addition, sodium chloride in this iron () composition is
It is preferable to contain 0.5 to 15% by weight in order to promote the deodorizing effect. In order for the iron () composition of the present invention to exhibit activity, it is necessary that an organic acid component such as ascorbic acid or citric acid be bound to the iron () compound as the main component. Such a composition can be prepared by once mixing and dissolving both components, and then drying and powdering an aqueous solution by a spray drying method, a freeze drying method, or the like. It is also preferable to add alum to the iron () composition to prevent denaturation of the film and stabilize the freshness retention and deodorizing functions. The amount of alum added varies depending on the purpose of the film and the form of use, but it is used up to 100% by weight based on the total amount of iron () compound and organic acid component, but it is 2 to 20% by weight.
A weight percent range is preferred. The alum is not particularly limited, but potassium alum, ammonia alum, sodium alum, etc. are preferred, with roasted alum being particularly preferred. The resin used in the present invention may be either a synthetic resin or a natural resin. Specific examples include polyolefins such as polyethylene and polypropylene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl compounds such as vinyl chloride-vinyl acetate copolymer, cellulose esters such as cellulose diacetate, and regenerated cellulose. , polyesters,
Examples include polyamide, hydrochloric acid rubber, natural rubbers, and fluororesins. The thickness of the film varies depending on the use of the film, the material, etc., but is usually preferably in the range of 0.01 to 0.5 mm, but of course films outside this range can also be produced. In the present invention, the term "film" does not particularly limit its thickness, and includes so-called sheet-like films. Furthermore, "plastic" does not mean thermoplastic, but has the same meaning as polymer in a broad sense. The content of the iron composition in the film of the present invention is preferably 0.5% by weight or more. The higher the upper limit, the better, but if it exceeds 5% by weight, the film will become cloudy, but there will be no problem in maintaining freshness or deodorizing function. The plastic film of the present invention can be produced by a conventional film forming method, such as a calendar method, a T-die method, an inflation method, or a solution casting method, except for mixing the iron() composition. But you can do it. More specifically, for example, in the case of the inflation method, an iron () compound composition is first mixed into the master pellet at a high concentration, and then a resin is added to this to reduce the concentration to 1/10.
It is preferable to melt-extrude a diluted product. In addition, conventional ingredients such as plasticizers, stabilizers, fillers, and other additives (coloring agents, etc.) may be added to the plastic film of the present invention to the extent that they do not impair the activity of the iron composition. Of course it is okay to do so. (Function) In the present invention, it is not yet clear how such a plastic film with low gas permeability exhibits the freshness effect of foods such as fruits, but the iron() composition in the film improves the atmosphere. This is thought to be due to the fact that the molecular oxygen present inside is converted into active superoxide (O ₂ ^- ), which has stronger oxidizing power than the original molecular oxygen, and this is maintained in a stable state. Fe()＋0 ² Fe()・0 ₂ Fe()・0 ₂ ^- Fe()・0 ₂ , Fe()Fe()・0 ₂・Fe() Fe()・0 ₂ ^-・Fe() It is thought that the sterilizing effect of superoxide also contributes to the freshness preserving effect of the method of the present invention. (Effects of the Invention) The plastic film of the present invention is a transparent film that is almost the same in appearance as a film that does not contain an iron composition, although its smoothness is slightly reduced. If the plastic film of the present invention is also used, it will have the excellent effect of keeping food fresh for a long time and preventing it from spoiling. This film can be used to wrap perishable foods such as vegetables, fruits, meat, seafood, and seafood products that tend to lose their freshness.
It is best to store it to maintain freshness, preserve it, and preserve it. More specifically, it is used as a storage bag for fruits, vegetables, etc., and as a casing film for kamaboko, sausages, etc. The present invention does not use any harmful fungicides and is a combination of ingredients that are safe for humans and livestock.Therefore, it can be used not only as a packaging material used at the distribution stage from production area to market, but also for end consumption by housewives and others. food,
It is particularly advantageous in that it can be easily used as a wrapping film for cooking, etc., and therefore can consistently maintain freshness from the place of production to the consumer. The film of the present invention also has a deodorizing effect, absorbing and removing bad odors and foreign odors from foods. Furthermore, the plastic film of the present invention is not limited to the above-mentioned uses. As such, it is flame retardant and antistatic, and can be used in sterilization, bioactive applications, and plant growth promotion. (Examples) Next, the present invention will be described in more detail based on Examples. Example An aqueous solution having the following composition was prepared.

[Table] Spray-dry 500 g of this aqueous solution using a spray dryer (DL-21 manufactured by Yamato Chemical Co., Ltd.) under the following conditions to combine ferrous sulfate and organic acid components to form a powder containing alum. A composition (PH approximately 3.0) was obtained. Operating conditions Liquid feed rate 40ml/min Spraying air flow rate 15/min Drying air flow rate ^6m2 /min Inlet temperature 120℃ Outlet temperature 75℃ [Film forming by inflation method] Next, 90 parts by weight of polyethylene master pellets and the above Iron () composition powder obtained from Experiment No. 2
10 parts by weight in a kneader at about 190 to 200℃,
Add 90 parts by weight of polyethylene to 10 parts by weight of this premix and heat at 190℃.
The mixture was kneaded and a film with a thickness of 0.05 mm was formed by aeration. (Contains 1% iron () composition by weight) [Freshness retention test] Lemons, melons and apples purchased from the market,
Each of the 10 pieces was divided into two parts, one part was wrapped in polyethylene film (24cm x 30cm cut appropriately) containing the above-mentioned iron() composition, and the other part was welded and sealed with an electric heat seal. I put it in a bag and sealed it as well. Seal both normally and do not vacuum. This fruit was stored at room temperature (28°C) and observed for freshness (color and gloss of the skin, growth of mold, hardness of the fruit, condition of the pulp when cut in half, and other conditions of the stem). The results are shown in Table 2. As is clear from the results in the same table, compared to conventional films, products packaged with the film of the present invention lasted about two weeks longer for lemons and melons, and after further testing, products packaged with the film of the present invention lasted about two weeks longer. I found out that it lasts for a month. [Deodorization Test] Next, a deodorization test was conducted using the test apparatus assembled as shown in FIG. A in the figure is a tetrabag,
B is a flowmeter, C is a column, and P is a pump. In the figure, put 5 g of the polyethylene film of the present invention, which was cut into pieces of about 5 mm square, into C, and into A, put the
NH ₃ gas of 1700 ppm or 240 ppm was taken, and the first concentration was measured after the whole was connected and the gas was circulated for 1 hour. Next, change to new NH ₃ gas of the same concentration and perform the same test (without changing the polyethylene sample). In this way, the same experiment was repeated six times. The results are shown in Tables 3 and 4.

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【table】 [Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a deodorization test device.

Claims (1)

[Claims] 1. A composition containing an iron () compound as a main component and an organic acid component (excluding ascorbic acids when used alone) bound to the resin. Characteristic plastic film. 2. The plastic film according to claim 1, wherein the composition contains alum. 3. The plastic film according to claim 1 or 2, wherein the composition contains sodium chloride.