JP2022064879A - Food product with film, coating composition, method for producing food product with film, film formation method, and food product shipping method - Google Patents

Abstract

To provide a food product with a film, a coating composition, a method for producing a food product with a film, a film formation method, and a food product shipping method which can maintain freshness of a food product without using a resin packaging film.SOLUTION: There are provided a food product with a film which has a film containing a saccharide-based surface active agent; a coating composition containing a saccharide-based surface active agent and an aqueous solvent; and a method for producing a food product with a film and a film formation method which coat the coating composition to a food product. A food product shipping method includes (A) a step of conveying a food product, (B) a step of forming a film on the food product, and (C) a step of inspecting a food product with a film using an evaluator, in which the step (B) forms a film by the coating film formation method.SELECTED DRAWING: None

Description

The present invention relates to a coated food, a coating composition, a method for producing a coated food, a film forming method, and a method for shipping the food.

In recent years, packaging materials that can maintain the freshness of food during distribution or storage, such as MA (Modified Atmosphere) packaging, have been attracting attention. From the viewpoint of reducing the environmental load, the packaging materials used tend to be made of a single material so that they can be easily recycled or disposed of after use, so-called monomaterials.
Therefore, a technique has been proposed in which a quality preservative is directly applied to foods such as fruits and vegetables to maintain the freshness of the foods (see Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2018-134115 Japanese Patent Publication No. 2005-530502

However, the above method has a short freshness retention period, the material used is a composition that is not friendly to the human body, and is not always sufficient for exhibiting freshness retention performance.
Therefore, it is an object of the present invention to propose a coated food, a coating composition, a method for producing a coated food, a film forming method, and a method for shipping the food, which can maintain the freshness of the food.

The present inventor considered that transpiration from food during distribution or storage was one of the factors for reducing the freshness, and examined various coating films having a high water vapor barrier property. Then, they have found that the above-mentioned problems can be solved by applying a coating film containing a specific surfactant to foods.

That is, the present invention has the following aspects.
[1] A food with a coating having a coating containing a sugar-based surfactant.
[2] The coated food according to [1], wherein the sugar-based surfactant is a sucrose fatty acid ester.
[3] The coated food according to [1] or [2], wherein the lipophilic group of the sugar-based surfactant is a saturated fatty acid.
[4] Any one of [1] to [3], which contains 50% by mass or more of a sugar fatty acid ester having 3 or less fatty acid ester groups when the total amount of the sugar-based surfactant is 100% by mass. The coated foods listed in 1.
[5] The coated food according to any one of [1] to [4], wherein the sugar-based surfactant has an HLB of 5 or more.
[6] The food with a film according to any one of [1] to [5], wherein the average film thickness of the film is 0.1 μm or more and 10 μm or less.
[7] The food with a coating according to any one of [1] to [6], wherein the crystal melting peak temperature of the coating is 40 ° C. or higher and 80 ° C. or lower.
[8] The food with a coating according to any one of [1] to [7], wherein the food is a fruit or vegetable.
[9] The coated food according to any one of [1] to [8], wherein the coating covers only a part of the food.
[10] A coating composition containing a sugar-based surfactant and an aqueous solvent.
[11] The coating composition according to [10], wherein the sugar-based surfactant is a sucrose fatty acid ester.
[12] The coating composition according to [10] or [11], wherein the lipophilic group of the sugar-based surfactant is a saturated fatty acid.
[13] Any one of [10] to [12] containing 50% by mass or more of a sugar fatty acid ester having 3 or less fatty acid ester groups when the total amount of the sugar-based surfactant is 100% by mass. The coating composition according to one.
[14] The coating composition according to any one of [10] to [13], wherein the sugar-based surfactant has an HLB of 5 or more.
[15] The coating composition according to any one of [10] to [14], wherein the content of the sugar-based surfactant among the non-volatile components in the coating composition is 60% by mass or more.
[16] The coating composition according to any one of [10] to [15], wherein the water-based solvent is water or alcohol.
[17] A film comprising the coating composition according to any one of [10] to [16].
[18] A film-coated food product comprising a step of applying the coating composition according to any one of [10] to [16] to the food product, or a step of applying the sugar-based surfactant to the food product without solvent. Production method.
[19] The method for producing a coated food according to [18], wherein the coating method is a dipping method or a spraying method.
[20] The method for producing a coated food product according to [18] or [19], wherein the coating composition or the sugar-based surfactant is applied to a part of the food product.
[21] The method according to [18] or [19], wherein after applying the coating composition or the sugar-based surfactant to a food, a part of the applied coating composition or the sugar-based surfactant is removed. How to make coated foods.
[22] A film forming method comprising a step of applying the coating composition according to any one of [10] to [16] to a food, or a step of applying a sugar-based surfactant to a food without a solvent.
[23] The film forming method according to [22], wherein the coating method is a dipping method or an injection method.
[24] The film-forming method according to [22] or [23], wherein the coating composition or the sugar-based surfactant is applied to a part of a food product.
[25] The above-mentioned [22] or [23], wherein after applying the coating composition or the sugar-based surfactant to a food, a part of the applied coating composition or the sugar-based surfactant is removed. Film forming method.
[26] A food shipping method including (A) a step of transporting food, (B) a step of forming a film on the food, and (C) a step of inspecting the coated food using an evaluation device. A method for shipping a food product, wherein a film is formed by the method according to any one of [22] to [25] in the step (B).
[27] The method for shipping a food product according to [26], wherein the inspection step (C) comprises at least one inspection selected from the group consisting of a visual inspection, a sugar content inspection, and a size inspection.

Since the coated food of the present invention has a film having a high water vapor barrier property, transpiration from the food can be suppressed, so that the freshness can be maintained for a long period of time. Since the film also has an oxygen barrier property, aging due to respiration can be suppressed, especially in fruits and vegetables.
Further, in the present invention, since the film having the freshness-retaining performance is directly provided on the food, the plastic packaging material is not required as in the conventional case, the filmless film can be achieved, and the contribution to the reduction of the environmental load is great.

It is an image diagram of the shipping method of the fruit and vegetable of this invention.

<Food with film>
The coated food of the present invention contains a sugar-based surfactant in the coating. Since the film has an excellent water vapor barrier property, transpiration from food can be suppressed and freshness can be maintained. In addition, since the film also has an oxygen barrier property, aging due to respiration can be suppressed, especially in fruits and vegetables.

The film does not necessarily have to cover the entire food, and may cover only a part of the food as long as it can suppress transpiration and respiration from the food.
For example, if the food is fruits and vegetables, the coating may cover only a part of the fruits and vegetables. The area of the coating is preferably 10% or more, more preferably 25% or more, still more preferably 40% or more, still more preferably 50% or more with respect to the surface area of the whole fruit and vegetable.
Further, from the viewpoint of maintaining the freshness of fruits and vegetables, it is preferable that the coating film at least covers a portion where water evaporates a lot. Examples of sites where water evaporates a lot include stomata, stems, fruit stalks, spikelets, gaku or roots, etc. on the back of leaves, or cut surfaces at the time of harvest.
Further, from the viewpoint of maintaining the freshness without significantly changing the appearance of fruits and vegetables, it is preferable to cover only the portion where the water evaporates a lot.

[Food]
Examples of the food in the present invention include fresh foods such as fruits and vegetables, meat and fish, and processed foods such as dairy products and bakery products.
Above all, since the coating film of the present invention has excellent water vapor barrier properties, it is preferably applied to fruits and vegetables or dairy products whose quality tends to deteriorate due to transpiration. Further, since the coating film also has an oxygen barrier property, it is more preferable to apply it to fruits and vegetables that undergo aging due to respiration.
Fruits and vegetables include, for example, citrus fruits such as apples, cherries, peaches, blue beech mushrooms, oranges, grapefruits, citrus fruits, and sardines, oysters, figs, strawberries, kiwifruits, grapes, blueberries, bananas, mangoes, melons, papayas, and reishi. (Lych), Anzu, Avocado, Cantarup, Guava, Nectarin, Pear (Japanese pear, Pear, etc.), Plum and other fruits; Kind; leafy stem vegetables such as asparagus, cabbage, lettuce, spinach, hakusai, cauliflower, broccoli; fruit vegetables such as tomato, eggplant, pumpkin, pepper, cucumber; wild vegetables such as warabi, zenmai; shiitake, eringi, beech mushroom, Fungi mushrooms such as Honshimaji, Enokidake, and Maitake; Cut flowers such as Kiku, rose, and lily can be mentioned.
Examples of dairy products include cheese and butter.

[Sugar-based surfactant]
The sugar-based surfactant is a nonionic surfactant having a sugar as a hydrophilic group.

The HLB of the sugar-based surfactant of the present invention is not particularly limited, but is preferably 5 or more, more preferably 7 or more, still more preferably 9 or more, from the viewpoint of being able to be dissolved in an aqueous solvent to form a film. The upper limit of HLB is usually 20, and more preferably 18 or less.

The sugar-based surfactant of the present invention is preferably crystalline from the viewpoint of suppressing the stickiness of the obtained film and enhancing the water vapor barrier property and the oxygen barrier property. The presence or absence of crystallinity of the sugar-based surfactant in the coating film can be confirmed by the presence or absence of the crystal melting peak temperature measured for the coating film. Therefore, it is preferable that the crystal melting peak derived from the sugar-based surfactant is detected in the DSC described later.
The crystal melting peak temperature of the coating film is preferably 40 ° C. or higher and 80 ° C. or lower, and more preferably 45 ° C. or higher and 70 ° C. or lower. When the crystal melting peak temperature is 40 ° C. or higher, the stickiness of the obtained film can be suppressed. On the other hand, when the crystal melting peak temperature is 80 ° C. or lower, heating can be reduced when dissolved in an aqueous solvent, and productivity is improved.
The crystal melting peak temperature is the temperature at which the crystal melting peak is detected in the differential scanning calorimetry (DSC) measured at a heating rate of 10 ° C./min.

From the viewpoint of suppressing the stickiness of the obtained film, the sugar-based surfactant of the present invention preferably contains 60% by mass or more, and 70% by mass or more, a component that becomes a solid at room temperature (20 to 25 ° C.). Is more preferable, 80% by mass or more is further preferable, and 90% by mass or more is further preferable. The sugar-based surfactant may be composed of only components that become solid at room temperature (20 to 25 ° C.), and therefore, the above ratio may be 100% by mass or less.

Examples of the sugar-based surfactant of the present invention include a sugar fatty acid ester formed by an ester bond between a sugar and a fatty acid, an alkyl glycoside formed by a glycosidic bond formed by a sugar and a higher alcohol, and the like, and a sugar fatty acid ester is particularly preferable.
The lipophilic group of the sugar-based surfactant is preferably a saturated fatty acid. Therefore, in the sugar fatty acid ester, it is preferable that the constituent fatty acids of the sugar fatty acid ester contain saturated fatty acids as described later. The details of the saturated fatty acid will be described later.

(Sugar fatty acid ester)
The sugar fatty acid ester is not particularly limited as long as it can be used for foods, and examples thereof include sucrose fatty acid ester, sorbitan fatty acid ester, and glucose ester, and sucrose fatty acid ester is preferable. Since the sucrose fatty acid ester can have a crystal structure, the water vapor barrier property and the oxygen barrier property of the obtained film are further enhanced.
The sugar-based surfactant does not have to be only one kind, and two or more kinds may be used in combination. When two or more kinds are combined, it is preferable that 60% by mass or more is sucrose fatty acid ester when the total amount of the sugar-based surfactant is 100% by mass. This ratio is more preferably 70% by mass or more, further preferably 80% by mass or more, still more preferably 90% by mass or more, from the viewpoint of suppressing the stickiness of the obtained film and increasing the water vapor barrier property and the oxygen barrier property. preferable. The sugar-based surfactant may be used alone as the sucrose fatty acid ester, and therefore, the above ratio may be 100% by mass or less.

The constituent fatty acids of the sugar fatty acid ester are preferably edible fats and oils.
The number of carbon atoms of the constituent fatty acids of the sugar fatty acid ester is not particularly limited, but is preferably 12 or more and 22 or less, more preferably 12 or more and 18 or less, and further preferably 14 or more and 18 or less. When the number of carbon atoms is in the above range, the stickiness of the obtained film can be suppressed.
The constituent fatty acids of the sugar fatty acid ester may be saturated or unsaturated fatty acids, but saturated fatty acids are preferable from the viewpoint that they tend to become solid at room temperature (20 to 25 ° C.) and the stickiness of the obtained film can be suppressed.
More specifically, lauric acid, myristic acid, pentadecic acid, palmitic acid, palmitic acid, margaric acid, stearic acid, oleic acid and the like can be mentioned, and among them, lauric acid, which is a saturated fatty acid having 12 or more and 18 or less carbon atoms. , Myristic acid, palmitic acid, stearic acid are preferable, and myristic acid, palmitic acid, stearic acid, which are saturated fatty acids having 14 or more and 18 or less carbon atoms, are more preferable. These saturated fatty acids may be used alone or in combination of two or more.
The constituent fatty acids of the sugar fatty acid ester do not have to be all the same, and 60% by mass or more of the constituent fatty acids in the sugar fatty acid ester may be the above-mentioned suitable constituent fatty acids. This ratio is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, from the viewpoint of suppressing the stickiness of the obtained film. The upper limit is not particularly limited, but may be 100% by mass or less.
The constituent fatty acid composition of the sugar fatty acid ester can be measured by gas chromatography after isolating the sugar fatty acid ester from the composition and then derivatizing it.

The range of the number of fatty acid ester groups of a sugar fatty acid ester varies depending on the number of hydroxyl groups that can be ester-bonded in the molecular structure of the sugar that is a hydrophilic group. 2 to 4 pieces.
In the present invention, from the viewpoint that a film can be formed by dissolving in an aqueous solvent, the number of fatty acid ester groups is 3 or less when the total amount of the sugar-based surfactant is 100% by mass (monoester, diester). Or a trimester) is preferably contained in an amount of 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more. The upper limit is not particularly limited, but may be 100% by mass or less.
From the same viewpoint, 30 sugar fatty acid esters (hexaester, heptaester, octaester or more) having 6 or more fatty acid ester groups when the total amount of the sugar-based surfactant is 100% by mass. It is preferably contained in an amount of% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. The sugar fatty acid ester having 6 or more fatty acid ester groups does not have to be contained, and the content thereof may be 0% by mass or more.

The content ratio for each number of fatty acid ester groups is determined by Isolating the sugar fatty acid ester from the composition, and then the Residence Monograph prepared by the meeting of the Joint FAO / WHO Expert Committee on Food Additives (JECFA), 84th meeting 2017 “Sucrose Esters. It can be measured according to METHOD OF ASSAY described in "of Fatty Acids" and Prepared at the 71st JECFA (2009) and published in FAO JECFA Monographs 7 (2009) "Sucrose Oligoesters Type I" and "Sucrose Oligoesters Type II". ..

<< Measurement of monoester-triester and tetraester or higher >>
After dissolving the sample in a certain amount of tetrahydrofuran (stabilizer-containing GPC or industrial grade), high performance liquid chromatography was performed under the following conditions using a solution from which insoluble matters had been removed with a 0.5 μm membrane filter as the measurement sample. do. For the composition ratio, the peak area of each of the monoester to the triester and the peak area of the tetraester and above are individually calculated, and the ratio of all the peaks detected by 43 minutes to the total peak area is calculated.
The peak area corresponds to the area from the start point (rising position) to the ending point (falling position) of each peak.
If two or more peaks are adjacent to each other and the start point and end point are unknown, the area is calculated with the point where the data between the peaks is the smallest as the start point and the end point.

<Measurement conditions: monoester-triester and tetraester or higher>
Device: HLC-8320GPC Detector: Differential refractometer (manufactured by Tosoh Corporation)
Column: TSK-Gel G1000HXL, G2000HXL, G3000HXL, G4000HXL (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Detector temperature: 40 ° C
Eluent: Tetrahydrofuran (stabilizer-containing GPC or industrial grade)
Flow velocity: 0.8 ml / min
Injection amount: 80 μl
Measurement time: 50 minutes (Area ratio is calculated based on all peaks detected by 43 minutes)

<< Measurement of tetraester-octaester >>
After dissolving the sample in a certain amount of methanol (special grade reagent) / tetrahydrofuran (stabilizer-free HPLC grade) = 20/80 (vоl / vоl), measure the solution from which the insoluble material was removed with a 0.45 μm membrane filter. Using the sample, perform high performance liquid chromatography under the following conditions. For the composition ratio of tetraester to octaester, the peak area of each of tetraester to octaester is calculated individually, and the ratio to the total peak area of tetraester to octaester is calculated. The area ratio above the tetraester obtained in the above measurement >> is calculated by dividing the area ratio from the tetraester to the octaester.
The peak area corresponds to the area from the start point (rising position) to the ending point (falling position) of each peak.
If two or more peaks are adjacent to each other and the start point and end point are unknown, the area is calculated with the point where the data between the peaks is the smallest as the start point and the end point.

<Measurement conditions: Tetra ester-Octa ester>
Equipment Degasser: DGU-20A (manufactured by Shimadzu Corporation)
Pump: LC-20AD (manufactured by Shimadzu Corporation)
Oven: CTO-20A (manufactured by Shimadzu Corporation)
Detector: RID-20A differential refractometer (manufactured by Shimadzu Corporation)
Column: 150 mm x 4.6 mm i. d. ODS-2 (manufactured by GL Science)
Column temperature: 40 ° C
Detector temperature: 40 ° C
Eluent: Methanol (special grade reagent) / tetrahydrofuran (polymer-free HPLC grade) = 70/30 to 50/50 (vоl / vоl)
Flow velocity: 0.8 ml / min
Injection amount: 20 μl
Measurement time: 16 minutes

[Physical characteristics of the film]
(Average film thickness)
The average film thickness of the coating film of the present invention is preferably 0.1 μm or more and 10 μm or less, and more preferably 0.5 μm or more and 5 μm or less. When the average film thickness is 0.1 μm or more, the water vapor barrier property and the oxygen barrier property are good. On the other hand, when the average film thickness is 10 μm or less, a film can be formed while maintaining the texture of the food.
In the present invention, the thickness of the coating film does not have to be uniform throughout the food.
The average film thickness of the film is measured by first freeze-drying the food with the film, peeling the film, observing the cross section with an electron microscope or a metallurgical microscope, and randomly selecting 10 points or more to measure the thickness. It can be calculated from the average value.

(Water vapor barrier)
The coating film of the present invention preferably has a water vapor transmittance of 0.1 to 20 g / (m ² · day) per 1 μm at 30 ° C. and 50% RH, and is preferably 0.5 to 10 g / (m ² · day). Is more preferable, and 1 to 5 g / (m ² · day) is even more preferable. When the water vapor permeability is within the above range, transpiration from food can be suppressed and freshness can be maintained.
The water vapor transmission rate (WVTR) can be measured by a differential pressure method using a water vapor transmission rate measuring device DELTAPERM based on JIS K7129-5. More specifically, the measured value of the water vapor transmittance when coated on a polyethylene terephthalate film having a thickness of 50 μm under the condition of 30 ° C. and 50% RH is converted into the transmittance per 1 μm by the following formula. be.

(Oxygen barrier property)
The coating film of the present invention preferably has an oxygen permeability of 0.1 to 100 cc / (m ² · day · atm) per 1 μm at 25 ° C. and 50% RH, and is preferably 0.5 to 90 cc / (m ² · atm). Day · atm) is more preferred, and 1 to 50 cc / (m ² · day · atm) is even more preferred. When the oxygen permeability is within the above range, the aging of fruits and vegetables due to respiration can be suppressed, and the freshness can be further maintained.
The oxygen permeability (OTR) can be measured by an isobaric method using an oxygen permeability measuring device OX-TRAN 2/21 (manufactured by MOCON) based on JIS K7126-2. More specifically, the measured value of the oxygen permeability when coated on a polyethylene terephthalate film having a thickness of 50 μm under the condition of 25 ° C. and 50% RH is converted into the transmittance per 1 μm by the following formula. be.

<Coating composition>
The coating composition of the present invention contains a sugar-based surfactant and an aqueous solvent. Since the film obtained from the coating composition has excellent water vapor barrier properties, the coating composition is suitable for food use. Further, since the film also has an oxygen barrier property, it is particularly suitable for fruits and vegetables. The film obtained from the coating composition may have the aqueous solvent removed as described later.

[Sugar-based surfactant]
As the sugar-based surfactant, those described in the above <Food with a film> can be used.

[Water-based solvent]
Examples of the aqueous solvent of the present invention include water; alcohols such as ethanol, isopropanol, ethylene glycol, and glycerin. From the viewpoint of being able to be applied to foods, it is preferable to use an aqueous coating composition using water as a solvent, but from the viewpoint of stability and coatability, it contains a small amount of the above-mentioned organic solvent such as alcohol in addition to water as a solvent. May be.
The content of the organic solvent in the coating composition is preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 10% by mass or less, still more preferably 5% by mass or less.

[PH regulator]
The coating composition of the present invention may contain a pH adjuster.
As the pH adjuster, for example, acetic acid, lactic acid, citric acid, ammonia and the like can be used.

[Physical characteristics of the coating composition]
(Non-volatile component concentration)
The concentration of the non-volatile component of the coating composition is not particularly limited, but is preferably 0.1% by mass or more and 60% by mass or less, more preferably 0.2% by mass or more and 50% by mass or less, and 0.3% by mass or more and 40% by mass or less. The following is further preferable, 0.5% by mass or more and 20% by mass or less is further preferable, and 1% by mass or more and 10% by mass or less is particularly preferable. By setting the concentration of the non-volatile component to 0.1% by mass or more and 60% by mass or less, it becomes easy to form a film having a suitable film thickness while appropriately dissolving the sugar-based surfactant in the aqueous solvent.
The "non-volatile component concentration" in the present invention is the concentration of the non-volatile component excluding the solvent contained in the coating composition.

(Contents of sugar-based surfactant)
The content of the sugar-based surfactant is 60% by mass or more, up to 100% by mass, among the non-volatile components in the coating composition, from the viewpoint of enhancing the water vapor barrier property and the oxygen barrier property of the obtained coating film. It is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.
Since the coating film in the present invention is obtained by volatilizing a solvent from the coating composition, the suitable content of the sugar-based surfactant in the coating film is the same as described above.

(PH of coating composition)
The pH of the coating composition is preferably 4 or more and 10 or less, and more preferably 4 or more and 8 or less, from the viewpoint of safe application to foods.

<Manufacturing method of coated food>
The coated food of the present invention is produced by a method of applying the coating composition to the food or a method of applying the sugar-based surfactant to the food without solvent. After applying the above coating composition to food, drying may be performed.
For the coating and drying of the coating composition and the solvent-free coating of the sugar-based surfactant, the methods described in the "film forming method" described later can be preferably used.

<Film formation method>
Examples of the film forming method of the present invention (hereinafter, also referred to as “the present method”) include a method of applying the coating composition to a food, or a method of applying the sugar-based surfactant to a food without a solvent.

[Applying coating composition]
When the coating composition is applied to a food, the application method is not particularly limited, and for example, a method of directly applying a coating liquid such as a brush coating or a curtain coat to a food; a dipping method such as an impregnation coating; a spray coating or the like. Injection method can be mentioned.
Of these, the dipping method or the jet method is preferable from the viewpoint of being able to relatively uniformly cover the surface of the food having a three-dimensional shape.
When the food is fruits and vegetables, a film may be formed on the surface of fruits and vegetables after harvesting, or a film may be formed on the surface of fruits and vegetables before harvesting, depending on the type of fruits and vegetables and the ease of application. May be good. If the film is formed before harvesting, it is desirable to form the film when the fruits and vegetables have reached the desired maturity.

In this method, from the viewpoint of shortening the drying time of the coating composition and increasing the efficiency of the film forming treatment, it is preferable to apply the coating composition to a part of the food.
For example, if the food is a fruit or vegetable, the coating composition may be applied to only a portion of the fruit or vegetable. In this case, the coating area is preferably 10% or more, more preferably 25% or more, further preferably 40% or more, still more preferably 50% or more, based on the surface area of the whole fruit and vegetable.
Further, from the viewpoint of maintaining the freshness of fruits and vegetables, it is preferable to apply the coating composition to at least a portion where water evaporates a lot.
From the viewpoint of minimizing the amount of the sugar-based surfactant used, the coating composition may be applied only to the portion where the water evaporation is large.

In this method, after applying the coating composition to food, a part of the applied coating composition may be removed. The removal method is not particularly limited, and examples thereof include removal by wind pressure using an air dryer.
For example, by removing the excess coating composition on the surface of the food, it is possible to prevent poor drying of the portion applied in an excessive amount.
Further, by removing the coating composition of a part of the food, the amount of the sugar-based surfactant used can be minimized.
When the food is fruits and vegetables, the coating composition of other parts may be removed because the freshness can be maintained by at least covering the part where the water evaporates a lot.
As for the coating method, there is an example described in "Coating Method" by Yuji Harasaki, Maki Shoten, published in 1979.

[Drying]
After applying the coating composition to the food, the coating may be dried for the purpose of removing the aqueous solvent or the like. Examples of the drying method include static drying, air drying, and heat drying. From the viewpoint of maintaining the freshness of the food, the drying method is a method of allowing the food to stand at room temperature (20 to 25 ° C.) for drying, or air drying at room temperature. The method is preferred.

[Solvent-free application of sugar-based surfactant]
When applying a sugar-based surfactant to food without a solvent, the sugar-based surfactant is heated to a temperature indicating fluidity (for example, melting point to melting point + 30 ° C. of the sugar-based surfactant), and then a curtain coat or a curtain coat or A method of applying to food with a spray coat or the like is preferable. When applied without a solvent, a food containing only a sugar-based surfactant may be applied to the food, but the sugar-based surfactant is appropriately mixed with other components (nonvolatile components, etc.) other than the solvent. You may apply the solvent.

Similar to the above [coating composition coating], it is preferable to apply the sugar-based surfactant to a part of the food from the viewpoint of increasing the efficiency of the film forming treatment. Further, after applying the sugar-based surfactant to the food, a part of the applied sugar-based surfactant may be removed.

<Food shipping method>
The food shipping method of the present invention includes (A) a step of transporting the food, (B) a step of forming a film on the food, and (C) a step of inspecting the coated food using an evaluation device. The step (B) is characterized in that a film is formed on food by the film forming method of the present invention. In this way, the food film formed and inspected is shipped to the place of consumption by transportation or the like.
The order of the steps (B) and (C) in the above shipping method may be reversed. That is, the order may be (A) step, (B) step, (C) step, or (A) step, (C) step, (B) step.
Hereinafter, the steps (A), (B), and (C) will be described in detail based on the image diagram shown in FIG. 1 by taking as an example.

FIG. 1 is an image diagram of the food shipping method of the present invention. The step of transporting the food (A) is a step of feeding the food to the step (B). The method is not particularly limited, and for example, it may be continuously conveyed by a belt conveyor or the like, or a large number of foods may be conveyed together by a truck or the like.
FIG. 1 shows an embodiment in which food 10 is conveyed by using a belt conveyor 11. The food 10 is placed on a belt conveyor and is subjected to the step (B) by rotating the rotary roll 12.

The next step (B) is a step of forming a film on the food 10 conveyed in the step (A). For the formation of the coating film, the method described in the above-mentioned "coating film forming method" can be preferably used.
FIG. 1 illustrates a dipping method, which is one of the preferred embodiments. The food 10 is immersed in a dipping tank 13 filled with the coating composition of the present invention, and the coating composition is applied to the surface of the food. The belt conveyor is provided with food fixing means such as claws, and the food 10 is carried in and out of the immersion tank in a fixed state. After that, the solvent is removed in the drying oven 14, and a film is formed on the food 10. However, the drying oven 14 may be omitted, and the food 10 may be allowed to stand at room temperature for drying, or drying may be omitted for solvent-free coating.

When a film is formed only on a part of the food in the step (B), it is preferable that the coating composition is applied or sprayed on the food 10 placed on the belt conveyor and transported to the drying oven 14. ..
Further, after only a part of the food 10 is immersed in the immersion tank 13 by a food gripping means such as a robot hand, the food may be placed on a belt conveyor with the immersion surface facing up and conveyed to the drying furnace 14.

After the food 10 is immersed in the immersion tank 13, a part of the applied coating composition may be removed by an air dryer (not shown) or the like.

Next, the step (C) is a step of inspecting the food 10 having the film formed in the step (B) using the evaluation device 15. As the evaluation device, an optical sensor, a weighing scale, a camera, or the like can be used.
(C) Examples of the inspection in the inspection step include various inspection items, and it is preferable to include at least one inspection selected from the group consisting of a visual inspection, a sugar content inspection, and a size inspection.
In the present invention, since the film has high transparency, it does not interfere with non-destructive inspection using light such as sugar content inspection. Therefore, the inspection method used for conventional foods ( For example, Japanese Patent Application Laid-Open No. 2012-78206) can be used as it is.

As described above, the coated food product that has undergone the (A) transport step, (B) film forming step, and (C) inspection step is shipped by ordinary means. FIG. 1 shows an example of shipping by the shipping vehicle 16.

Next, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the examples described below.

<Test Example 1: Japanese pear (Kosui)>
In Test Example 1, a film was formed on the surface of Japanese pear (Kosui) to evaluate the freshness retention.

[Example 1]
"Ryoto (registered trademark) sugar ester L-1695" (sucrose lauric acid ester, HLB: 16, mono-triester content: 96% by mass or more) manufactured by Mitsubishi Chemical Co., Ltd. is used as a sugar-based surfactant, and is sugar-based. The aqueous coating composition 1-1 was prepared by dissolving it in water so that the content of the surfactant was 5% by mass.
The above-mentioned aqueous coating composition 1-1 was applied to the surface of Japanese pear by a dipping method and dried at room temperature (20 to 25 ° C.) for 30 minutes to form a film having a thickness of 1.5 μm.

[Example 2]
"Ryoto (registered trademark) sugar ester P-1570" (sucrose palmitic acid ester, HLB: 15, mono-triester content: 96% by mass or more) manufactured by Mitsubishi Chemical Co., Ltd. is used as a sugar-based surfactant, and is sugar-based. The aqueous coating composition 1-2 was prepared by dissolving in water so that the content of the surfactant was 5% by mass.
Using the above-mentioned aqueous coating composition 1-2, a film having a thickness of 1.5 μm was formed in the same manner as in Example 1.

[Example 3]
"Ryoto (registered trademark) sugar ester S-570" (sucrose stearic acid ester, HLB: 5, mono-triester content: 86% by mass or more) manufactured by Mitsubishi Chemical Co., Ltd. is used as a sugar-based surfactant, and is sugar-based. The aqueous coating composition 1-3 was prepared by dissolving in water so that the content of the surfactant was 5% by mass.
Using the above-mentioned aqueous coating composition 1-3, a coating film having a thickness of 1.5 μm was formed in the same manner as in Example 1.

[Example 4]
"Ryoto (registered trademark) sugar ester S-1670" (sucrose stearic acid ester, HLB: 16, mono-triester content: 97% by mass or more) manufactured by Mitsubishi Chemical Co., Ltd. is used as a sugar-based surfactant, and is sugar-based. The aqueous coating composition 1-4 was prepared by dissolving in water so that the content of the surfactant was 5% by mass.
Using the above-mentioned aqueous coating composition 1-4, a film having a thickness of 1.5 μm was formed in the same manner as in Example 1.

[Comparative Example 1]
Japanese pear that does not form a film was designated as Comparative Example 1.

[Freshness preservation evaluation]
The film-coated Japanese pears of Examples 1 to 4 and the Japanese pears of Comparative Example 1 were evaluated for freshness by weight retention rate, hardness maintenance rate, color and taste.
Japanese pear is already sweet enough in an immature state and is in a state suitable for eating. The color of Japanese pear changes from green to brown as it ages, and if it matures too much, the original crispy texture of Japanese pear is lost and the commercial value decreases.
For the above reasons, for Japanese pears, in addition to the weight retention rate for confirming transpiration suppression, the freshness retention effect was confirmed by the hardness maintenance rate, color and taste.

(Weight maintenance rate)
For the coated Japanese pears of Examples 1 to 4 and the Japanese pears of Comparative Example 1, the weight was maintained after storage at 20 ° C. and 90% RH for 10 days and 14 days based on the weight of the Japanese pears before storage (0 days). The rate ((weight after storage / weight on 0 days) × 100 (%)) was calculated.

(Hardness maintenance rate)
For the coated Japanese pears of Examples 1 to 4 and the Japanese pears of Comparative Example 1, the hardness at break of the cross section of the Japanese pears was measured using a fruit hardness meter KM-5 (manufactured by Fujiwara Seisakusho Co., Ltd.). The tip of the fruit hardness tester was a cylindrical one. Hardness maintenance rate after 14 days storage at 20 ° C. and 90% RH based on the hardness of Japanese pear before storage (0 days) ((Hardness after 14 days storage / 0 day hardness) x 100 (%)) Asked.

(colour)
The ground color of the coated Japanese pears of Examples 1 to 4 and the Japanese pears of Comparative Example 1 was evaluated using a fruit color chart supervised by the Fruit Tree Experiment Station of the Ministry of Agriculture, Forestry and Fisheries. The evaluation was performed twice, before storage (0 days) and after storage at 20 ° C. and 90% RH for 10 days. In addition, the evaluation by this fruit color chart shows that the ripening progresses as the numerical value becomes larger.

(Taste)
The filmed Japanese pears of Examples 1 to 4 and the Japanese pears of Comparative Example 1 were subjected to a taste test by four subjects and evaluated according to the following criteria. The evaluation was performed twice, before storage (0 days) and after storage at 20 ° C. and 90% RH for 14 days. As mentioned above, since the texture of Japanese pear also affects the commercial value, the evaluation of B or higher was passed and C was rejected. Table 1 shows the evaluation with the largest number of subjects among the evaluations of the four subjects. If the evaluations were divided between two people, the lower evaluation was listed in the table.
A: It has the same texture as the blank (state of 0 days in Comparative Example 1) Japanese pear.
B: Compared to the blank, the original crispy texture of Japanese pear is less.
C: There is no crispy texture at all.

Table 1 shows the configurations and evaluation results of Examples 1 to 4 and Comparative Example 1.

From Table 1, the coated Japanese pears of Examples 1 to 4 were superior to the Japanese pears of Comparative Example 1 in all of the weight retention rate, hardness retention rate, color and taste. It was confirmed that the freshness-maintaining effect can be obtained by providing the coating film containing.

<Test Example 2: Avocado>
In Test Example 2, a film was formed on the surface of the avocado and the freshness was evaluated.

[Example 5]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-570" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 2-1 was prepared.
The above-mentioned aqueous coating composition 2-1 was applied to the surface of avocado by a dipping method and dried at room temperature (20 to 25 ° C.) for 30 minutes to form a film having a thickness of 1.5 μm.

[Example 6]
"Ryoto (registered trademark) sugar ester S-970" (sucrose stearic acid ester, HLB: 9, mono-triester content: 92% by mass or more) manufactured by Mitsubishi Chemical Co., Ltd. is used as a sugar-based surfactant, and is sugar-based. The aqueous coating composition 2-2 was prepared by dissolving it in water so that the content of the surfactant was 5% by mass.
Using the above-mentioned aqueous coating composition 2-2, a coating film having a thickness of 1.5 μm was formed in the same manner as in Example 5.

[Example 7]
"Ryoto (registered trademark) sugar ester S-1170" (sucrose stearic acid ester, HLB: 11, mono-triester content: 94% by mass or more) manufactured by Mitsubishi Chemical Co., Ltd. is used as a sugar-based surfactant, and is sugar-based. The aqueous coating composition 2-3 was prepared by dissolving in water so that the content of the surfactant was 5% by mass.
Using the above-mentioned aqueous coating composition 2-3, a film having a thickness of 1.5 μm was formed in the same manner as in Example 5.

[Example 8]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1670" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 2-4 was prepared.
Using the above-mentioned aqueous coating composition 2-4, a film having a thickness of 1.5 μm was formed in the same manner as in Example 5.

[Comparative Example 2]
Avocado that does not form a film was designated as Comparative Example 2.

[Freshness preservation evaluation]
The avocado with a coating of Examples 5 to 8 and the avocado of Comparative Example 2 were evaluated for freshness retention by weight retention rate, hardness and color.
Avocados soften as they age, changing color from green to black-purple. Since these changes are easy to understand for avocados and it is common for consumers to evaluate the freshness of avocados by hardness and color, for avocados, in addition to the weight retention rate for confirming transpiration suppression. The effect of maintaining freshness was confirmed by the hardness and color.

(Weight maintenance rate)
For the avocado with a coating of Examples 5 to 8 and the avocado of Comparative Example 2, based on the weight of the avocado before storage (0 days), at 25 ° C. and 50% RH, 3 days, 8 days, 11 days and 16 days. The weight retention rate after storage ((weight after storage / weight on 0 days) × 100 (%)) was determined.

(Hardness)
Four avocados with a coating of Examples 5 to 8 and four avocados of Comparative Example 2 were prepared, and the hardness when the surface was lightly pressed with a finger was evaluated.
◯ (good): Hardness equivalent to or slightly softer than that of a blank (state of 0 days in Comparative Example 2), and deformation is small even when the surface is pressed.
× (bad): It is considerably softer than the blank and is greatly deformed when the surface is pressed.
The above evaluation was performed 6 times before storage (0 days) and after storage at 25 ° C. and 50% RH for 3 days, 8 days, 11 days, 16 days, and 21 days, and the change in hardness was evaluated according to the following criteria. bottom.
A: More than 75% of the samples can be evaluated as ○ (good).
B: The number of samples that can be evaluated as ◯ (good) is more than 50% and 75% or less.
C: The number of samples that can be evaluated as ◯ (good) is more than 25% and 50% or less.
D: The number of samples that can be evaluated as ◯ (good) is more than 0% and 25% or less.
E: There is no sample that can be evaluated as ○ (good) (0%).

(colour)
Four avocados with a coating of Examples 5 to 8 and four avocados of Comparative Example 2 were prepared, and the color change was evaluated according to the following criteria. The evaluation was performed 5 times before storage (0 days) and after storage at 25 ° C. and 50% RH for 3 days, 8 days, 11 days, and 16 days, and the color change was evaluated according to the following criteria.
A: There is no sample (0%) whose surface is completely black-purple, or less than 25%.
B: 25% or more and less than 50% of the samples have a completely black-purple surface.
C: More than 50% and less than 75% of the samples have a completely black-purple surface.
D: The number of samples whose surface is completely black-purple is 75% or more and less than 100%.
E: The surface of all samples is completely black-purple (100%).

Table 2 shows the configurations and evaluation results of Examples 5 to 8 and Comparative Example 2.

From Table 2, since the coated avocados of Examples 5 to 8 were superior to the avocados of Comparative Example 2 in all of the weight retention rate, hardness and color change, a sugar-based surfactant was applied to the surface of the avocado. It was confirmed that the freshness-maintaining effect can be obtained by providing the including film.

<Test Example 3: Oyster>
In Test Example 3, a film was formed on the surface of the oyster and the freshness was evaluated.

[Example 9]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-570" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 3-1 was prepared.
The above-mentioned aqueous coating composition 3-1 was applied to the surface of oysters by a dipping method and dried at room temperature (20 to 25 ° C.) for 30 minutes to form a film having a thickness of 1.5 μm.

[Example 10]
Using "Ryoto (registered trademark) Sugar Ester S-1170" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant, dissolve it in water so that the content of the sugar-based surfactant is 0.5% by mass, and apply an aqueous coating. Composition 3-2 was prepared.
Using the above-mentioned aqueous coating composition 3-2, a film having a thickness of 0.15 μm was formed in the same manner as in Example 9.

[Example 11]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1170" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 2% by mass. 3-3 was prepared.
Using the above-mentioned aqueous coating composition 3-3, a film having a thickness of 0.6 μm was formed in the same manner as in Example 9.

[Example 12]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1170" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 3-4 was prepared.
Using the above-mentioned aqueous coating composition 3-4, a film having a thickness of 1.5 μm was formed in the same manner as in Example 9.

[Example 13]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1670" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 3-5 was prepared.
Using the above-mentioned aqueous coating composition 3-5, a film having a thickness of 1.5 μm was formed in the same manner as in Example 9.

[Comparative Example 3]
The oyster that does not form a film was designated as Comparative Example 3.

[Freshness preservation evaluation]
The coated oysters of Examples 9 to 13 and the oysters of Comparative Example 3 were evaluated for freshness retention based on the weight retention rate and the hardness retention rate.
It is easy to see the change that oysters become softer as they age, and it is common for consumers to evaluate the freshness of persimmons by hardness. In addition, the freshness retention effect was confirmed by the hardness maintenance rate.

(Weight maintenance rate)
The coated oysters of Examples 9 to 13 and the oysters of Comparative Example 3 were stored at 25 ° C. and 50% RH for 7 days, 9 days, and 12 days based on the weight of the oysters before storage (0 days). Weight retention rate ((weight after storage / weight on 0 days) × 100 (%)) was determined.

(Hardness maintenance rate)
Six oysters with a film of Examples 9 to 13 and six oysters of Comparative Example 3 were prepared, and the ratio of the samples that passed the following criteria was taken as the hardness maintenance rate (Reference; Journal of the Japanese Society for Horticultural Science / Volume 38 (1969). ) Relationship between post-harvest maturation and respiratory type of No. 2 fruit (1st report) Presence or absence of respiratory climate in oyster fruits, Takashi Iwata, Katsuya Nakagawa, Kuniyasu Ogata).
A: Hard enough.
B: It's quite soft overall, but it's solid.
C: If you press it with your finger, it will almost collapse. Or a part of the flesh becomes water-soaked.
D: Very soft. Or part of the pericarp is ruptured.
Measurements were performed according to this index, and C and D rank fruits were evaluated as softened (failed).

Table 3 shows the configurations and evaluation results of Examples 9 to 13 and Comparative Example 3.

From Table 3, the coated oysters of Examples 9 to 13 were superior in both weight retention rate and hardness retention rate to the oysters of Comparative Example 3, and therefore, the oyster surface was coated with a sugar-based surfactant. It was confirmed that the effect of preserving freshness can be obtained by providing the above.

<Test Example 4: Sudachi>
In Test Example 4, a film was formed on the surface of Sudachi and the freshness was evaluated.

[Example 14]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1670" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 4-1 was prepared.
The above-mentioned aqueous coating composition 4-1 was applied to the surface of Sudachi by a dipping method and dried at room temperature (20 to 25 ° C.) for 30 minutes to form a film having a thickness of 1.5 μm.

[Comparative Example 4]
Sudachi, which does not form a film, was designated as Comparative Example 4.

[Freshness preservation evaluation]
The filmed sudachi of Example 14 and the sudachi of Comparative Example 4 were evaluated for freshness retention by weight retention rate and color.
It is easy to understand the change in color of sudachi from green to yellow as it ages, and it is common for consumers to evaluate the freshness of sudachi by color, so for sudachi, to confirm transpiration suppression. In addition to the weight retention rate of Sudachi, the freshness retention effect was confirmed by the color.

(Weight maintenance rate)
The weights of the coated sudachi of Example 14 and the sudachi of Comparative Example 4 after being stored at 15 ° C. and 90% RH for 6 days, 8 days, and 11 days based on the weight of the sudachi before storage (0 days). The maintenance rate ((weight after storage / weight on 0 days) × 100 (%)) was determined.

(colour)
Five coated sudachi of Example 14 and five of Comparative Example 4 sudachi were prepared and the color change was evaluated.
◯ (good): 80% or more of the entire surface is green, which is equivalent to the blank (state of Comparative Example 4 on day 0).
X (no good): Less than 80% of the entire surface is green, which is equivalent to a blank (state of Comparative Example 4 on day 0).
The above evaluation was carried out four times before storage (0 days) and after storage at 15 ° C. and 90% RH for 6 days, 8 days and 11 days, and the color change was evaluated according to the following criteria.
A: More than 80% of the samples can be evaluated as ○ (good).
B: The number of samples that can be evaluated as ◯ (good) is more than 60% and 80% or less.
C: The number of samples that can be evaluated as ◯ (good) is more than 40% and 60% or less.
D: The number of samples that can be evaluated as ◯ (good) is more than 20% and 40% or less.
E: The number of samples that can be evaluated as ◯ (good) is 20% or less.

Table 4 shows the configurations and evaluation results of Example 14 and Comparative Example 4.

From Table 4, since the coated sudachi of Example 14 was superior to the sudachi of Comparative Example 4 in both weight retention rate and color change, a coating containing a sugar-based surfactant was provided on the surface of the sudachi. It was confirmed that the effect of maintaining freshness can be obtained.

<Test Example 5: Water vapor barrier property>
In Test Example 5, a coating film was formed on a polyethylene terephthalate film and the water vapor barrier property was evaluated.

[Example 15]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-570" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 2% by mass. 5-1 was prepared.
The above-mentioned water-based coating composition 5-1 was previously applied to a PET film (50 μm thick, manufactured by Toyobo Co., Ltd .: A4160 type) corona-treated on the highly smooth surface side with a # 20 bar coater, and 24 at room temperature (20 to 25 ° C.). After drying for an hour, a coating film having a thickness (after drying) of 0.74 μm was formed on the PET film.

[Example 16]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1670" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 2% by mass. 5-2 was prepared.
Using the above-mentioned aqueous coating composition 5-2, a coating film having a thickness of 0.58 μm was formed in the same manner as in Example 15.

[Example 17]
The PET film with a coating film obtained in Example 16 was heated at 70 ° C. for 15 minutes and then cooled.

[Comparative Example 5]
A PET film that does not form a coating film was designated as Comparative Example 5.

[Evaluation of water vapor barrier property]
The PET film with a coating film of Examples 15 to 17 and the PET film of Comparative Example 5 were measured at 30 ° C. and 50% RH at 30 ° C. using a water vapor transmittance measuring device DELTAPERM manufactured by Technolux based on the JIS K7129-5 method. The water vapor permeability under the conditions was measured.
Further, for the PET films with coating films of Examples 15 to 17, the water vapor transmittance per 1 μm of the coating film was determined by the following formula.

Table 5 shows the configurations and evaluation results of Examples 15 to 17 and Comparative Example 5.

From Table 5, since the PET film with the coating film of Examples 15 to 17 was superior to the PET film of Comparative Example 5 in the water vapor barrier property, the film containing the sugar-based surfactant has the water vapor barrier property. Was confirmed.
Further, in Examples 16 and 17, the water vapor barrier property changed before and after the heat treatment. Since the sugar-based surfactant (S-1670) used in Examples 16 and 17 has a slow crystal growth, the coating film before the heat treatment has a crystal structure of the sugar-based surfactant in the coating film. On the other hand, the coating film after the heat treatment does not have the crystal structure of the sugar-based surfactant. Therefore, from the results of Examples 16 and 17, it was confirmed that the water vapor barrier property was further improved by the coating film having a crystal structure.

<Test Example 6: Oxygen barrier property>
In Test Example 6, a coating film was formed on a polyethylene terephthalate film and the oxygen barrier property was evaluated.

[Example 18]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1170" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 2% by mass. 6-1 was prepared.
The above-mentioned aqueous coating composition 6-1 was previously applied to a PET film (50 μm thick, manufactured by Toyobo Co., Ltd .: A4160 type) corona-treated on the highly smooth surface side with a # 20 bar coater, and 24 at room temperature (20 to 25 ° C.). After drying for an hour, a coating film having a thickness (after drying) of 0.42 μm was formed on the PET film.

[Example 19]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1170" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 6-2 was prepared.
Using the above-mentioned aqueous coating composition 6-2, a coating film having a thickness of 0.56 μm was formed in the same manner as in Example 18.

[Example 20]
The PET film with a coating film obtained in Example 19 was heated at 70 ° C. for 15 minutes and then cooled.

[Comparative Example 6]
Comparative Example 6 was a PET film that did not form a coating film.

[Oxygen barrier property evaluation]
With respect to the PET film with a coating film of Examples 18 to 20 and the PET film of Comparative Example 6, 25 using the oxygen permeability measuring device "OX-TRAN 2/21" manufactured by MOCON based on JIS K7126-2. Oxygen permeability was measured under the conditions of ° C. and 50% RH.
Further, for the PET films with coating films of Examples 18 to 20, the oxygen permeability per 1 μm of the coating film was determined by the following formula.

Table 6 shows the configurations and evaluation results of Examples 18 to 20 and Comparative Example 6.

From Table 6, since the PET film with the coating film of Examples 18 to 20 was superior in oxygen barrier property to the PET film of Comparative Example 6, the film containing the sugar-based surfactant has an oxygen barrier property. Was confirmed.
Further, in Examples 19 and 20, the oxygen barrier property changed before and after the heat treatment. Since the sugar-based surfactant (S-1170) used in Examples 19 and 20 has a slow crystal growth, the coating film before the heat treatment has a crystal structure of the sugar-based surfactant in the coating film. On the other hand, the coating film after the heat treatment does not have the crystal structure of the sugar-based surfactant. Therefore, from the results of Examples 19 and 20, it was confirmed that the oxygen barrier property was further improved by the coating film having a crystal structure.

<Test Example 7: Shine Muscat>
In Test Example 7, a film was formed on the surface of Shine Muscat to evaluate the freshness retention.

[Example 21]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1170" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 7-1 was prepared.
The above-mentioned aqueous coating composition 7-1 was applied to the surface of Shine Muscat by a dipping method and dried at room temperature (20 to 25 ° C.) for 30 minutes to form a film having a thickness of 1.5 μm.

[Comparative Example 7]
Shine Muscat, which does not form a film, was designated as Comparative Example 7.

[Freshness preservation evaluation]
Shine Muscat is known to cause browning of the cob when the freshness decreases. Therefore, the filmed Shine Muscat of Example 21 and the Shine Muscat of Comparative Example 7 were evaluated for freshness retention by the color of the cob.

(colour)
Eight Shine Muscats with a coating of Example 21 and eight Shine Muscats of Comparative Example 7 were prepared, and the change in the color of the cob was evaluated.
◯ (good): On the entire surface of the cob, 80% or more of the green portion is equivalent to the blank (state of Comparative Example 7 on day 0).
X (no good): On the entire surface of the cob, less than 80% of the green portion is equivalent to the blank (state of Comparative Example 7 on day 0).
The above evaluation was performed 5 times before storage (0 days) and after storage at 5 ° C. and 50% RH for 13 days, 15 days, 18 days and 21 days, and the color change was evaluated according to the following criteria.
A: More than 75% of the samples can be evaluated as ○ (good).
B: The number of samples that can be evaluated as ◯ (good) is more than 50% and 75% or less.
C: The number of samples that can be evaluated as ◯ (good) is more than 25% and 50% or less.
D: The number of samples that can be evaluated as ◯ (good) is more than 0% and 25% or less.
E: There is no sample that can be evaluated as ○ (good) (0%).

Table 7 shows the configurations and evaluation results of Example 21 and Comparative Example 7.

From Table 7, since the change in the color of the cob was smaller in the coated Shine Muscat of Example 21 than in the Shine Muscat of Comparative Example 7, by providing a coating containing a sugar-based surfactant on the surface of the Shine Muscat, It was confirmed that the effect of maintaining freshness can be obtained.

<Test Example 8: Kyoho>
In Test Example 8, a film was formed on the surface of Kyoho and the freshness was evaluated.

[Example 22]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1170" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 8-1 was prepared.
The above-mentioned aqueous coating composition 8-1 was applied to the surface of Kyoho by a dipping method and dried at room temperature (20 to 25 ° C.) for 30 minutes to form a film having a thickness of 1.5 μm.

[Comparative Example 8]
Kyoho, which does not form a film, was designated as Comparative Example 8.

[Freshness preservation evaluation]
Kyoho is known to cause browning of the cob when the freshness decreases. Therefore, the Kyoho with a coating of Example 22 and the Kyoho of Comparative Example 8 were evaluated for freshness retention by the color of the cob.

(colour)
Six Kyoho with a coating of Example 22 and six Kyoho of Comparative Example 8 were prepared, and the change in the color of the cob was evaluated.
◯ (good): On the entire surface of the cob, 80% or more of the green portion is equivalent to the blank (state of Comparative Example 8 on day 0).
X (no good): On the entire surface of the cob, less than 80% of the green portion is equivalent to the blank (state of Comparative Example 8 on day 0).
The above evaluation was carried out four times before storage (0 days) and after storage at 5 ° C. and 50% RH for 10 days, 13 days and 16 days, and the color change was evaluated according to the following criteria.
A: More than 80% of the samples can be evaluated as ○ (good).
B: The number of samples that can be evaluated as ◯ (good) is more than 60% and 80% or less.
C: The number of samples that can be evaluated as ◯ (good) is more than 40% and 60% or less.
D: The number of samples that can be evaluated as ◯ (good) is more than 20% and 40% or less.
E: The number of samples that can be evaluated as ◯ (good) is 20% or less.

Table 8 shows the configurations and evaluation results of Example 22 and Comparative Example 8.

From Table 8, since the change in the color of the cob was smaller in the coated Kyoho of Example 22 than in the Kyoho of Comparative Example 8, freshness was maintained by providing a coating containing a sugar-based surfactant on the surface of the Kyoho. It was confirmed that the effect was obtained.

<Test Example 9: Strawberry>
In Test Example 9, a film was formed on the surface of the strawberry (Kaorino) to evaluate the freshness retention.

[Example 23]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester P-1570" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 9-1 was prepared.
The aqueous coating composition 9-1 was applied to the surface of the strawberry by a dipping method and dried at room temperature (20 to 25 ° C.) for 30 minutes to form a film having a thickness of 1.5 μm.

[Example 24]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1670" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 9-2 was prepared.
Using the above-mentioned aqueous coating composition 9-2, a coating film having a thickness of 1.5 μm was formed in the same manner as in Example 23.

[Comparative Example 9]
Comparative Example 9 was a strawberry that did not form a film.

[Freshness preservation evaluation]
The coated strawberry of Examples 23 and 24 and the strawberry of Comparative Example 9 were evaluated for freshness retention based on the gloss retention rate, the freshness of the gaku and the weight retention rate.
It is known that when the freshness of strawberry decreases, the surface of the strawberry loses its luster and the gaku withers. It was confirmed.

(Gloss maintenance rate)
16 coated strawberry of Examples 23 and 24 and 16 strawberry of Comparative Example 9 were prepared respectively, and the change in surface gloss was evaluated.
◯ (good): On the entire surface of the strawberry, 80% or more of the glossy portion is equivalent to that of the blank (state of Comparative Example 9 on day 0).
X (no good): On the entire surface of the strawberry, less than 80% has a glossy portion equivalent to that of a blank (state of Comparative Example 9 on day 0).
The above evaluation was performed 4 times before storage (0 days) and after storage at 5 ° C. and 50% RH for 3 days, 7 days, and 9 days, and the change in surface gloss was evaluated according to the following criteria.
A: More than 80% of the samples can be evaluated as ○ (good).
B: The number of samples that can be evaluated as ◯ (good) is more than 60% and 80% or less.
C: The number of samples that can be evaluated as ◯ (good) is more than 40% and 60% or less.
D: The number of samples that can be evaluated as ◯ (good) is more than 20% and 40% or less.
E: The number of samples that can be evaluated as ◯ (good) is 20% or less.

(Freshness of gaku)
16 coated strawberry of Examples 23 and 24 and 16 strawberry of Comparative Example 9 were prepared respectively, and the change in freshness of gaku was evaluated.
◯ (good): In one strawberry, the number of twisted leaves of gaku is one or less.
X (no good): In one strawberry, the number of kinked leaves of gaku exceeds one.
The above evaluation was performed 4 times before storage (0 days) and after storage at 5 ° C. and 50% RH for 3 days, 7 days and 9 days, and the change in freshness of gaku was evaluated according to the following criteria.
A: More than 80% of the samples can be evaluated as ○ (good).
B: The number of samples that can be evaluated as ◯ (good) is more than 60% and 80% or less.
C: The number of samples that can be evaluated as ◯ (good) is more than 40% and 60% or less.
D: The number of samples that can be evaluated as ◯ (good) is more than 20% and 40% or less.
E: The number of samples that can be evaluated as ◯ (good) is 20% or less.

(Weight maintenance rate)
The coated strawberry of Examples 23 and 24 and the strawberry of Comparative Example 9 were stored at 5 ° C. and 50% RH for 3 days, 7 days and 9 days based on the weight of the strawberry before storage (0 days). Weight retention rate ((weight after storage / weight on 0 days) × 100 (%)) was determined.

Table 9 shows the configurations and evaluation results of Examples 23 and 24 and Comparative Example 9.

From Table 9, the coated strawberry of Examples 23 and 24 maintained the luster and freshness of the gaku as compared with the strawberry of Comparative Example 9, and was also excellent in the weight retention rate. It was confirmed that the freshness-maintaining effect can be obtained by providing the film containing the activator.

<Test Example 10: Partial coating>
In Test Example 10, the efficiency of the film forming treatment and the effect on the freshness-maintaining effect when a film was formed on a part of avocado, oyster, and strawberry (red cheek) were evaluated.

[Example 25]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1670" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 3% by mass. 10-1 was prepared.
The above-mentioned aqueous coating composition 10-1 is applied to the entire surface of the avocado by a dipping method, allowed to stand at room temperature (20 to 25 ° C.), and the time (drying time) until the coating film is not sticky on the entire surface is confirmed. bottom.

[Example 26]
The avocado was allowed to stand and the water-based coating composition 10-1 was sprayed from above to the extent that the surface was wet to form a coating film on only one side of the avocado (50% or more with respect to the total surface area). After allowing to stand at room temperature (20 to 25 ° C.), the time (drying time) until the coating film was not sticky on the entire surface was confirmed.

[Comparative Example 10]
Avocado that does not form a film was designated as Comparative Example 10.

[Freshness preservation evaluation (avocado)]
The coated avocados of Examples 25 to 26 and the avocados of Comparative Example 10 were evaluated for freshness retention by weight retention rate, hardness and color according to the same criteria as in Test Example 2.

[Example 27]
An aqueous coating composition using "Ryoto (registered trademark) Sugar Ester S-1170" manufactured by Mitsubishi Chemical Corporation as a sugar-based surfactant and dissolving it in water so that the content of the sugar-based surfactant is 5% by mass. 10-2 was prepared.
The above-mentioned aqueous coating composition 10-2 is applied to the entire surface of the oyster by a dipping method, allowed to stand at room temperature (20 to 25 ° C.), and the time (drying time) until the coating film is not sticky on the entire surface is confirmed. bottom.

[Example 28]
The oyster's oyster portion was immersed in the above-mentioned aqueous coating composition 10-2 with the oyster portion facing downward, and a coating film was formed only around the oyster. After allowing to stand at room temperature (20 to 25 ° C.), the time (drying time) until the coating film was not sticky on the entire surface was confirmed.

[Comparative Example 11]
The oyster that does not form a film was designated as Comparative Example 11.

[Freshness preservation evaluation (oyster)]
The coated oysters of Examples 27 to 28 and the oysters of Comparative Example 11 were evaluated for freshness retention based on the weight retention rate and the hardness retention rate based on the same criteria as in Test Example 3.

[Example 29]
The above-mentioned aqueous coating composition 10-1 is applied to the entire surface of the strawberry by a dipping method, allowed to stand at room temperature (20 to 25 ° C.), and the time (drying time) until the coating film is not sticky on the entire surface is confirmed. bottom.

[Example 30]
The strawberry was allowed to stand and the aqueous coating composition 10-1 was sprayed from above to the extent that the surface was wet to form a coating film on only one side of the strawberry (50% or more with respect to the total surface area). After allowing to stand at room temperature (20 to 25 ° C.), the time (drying time) until the coating film was not sticky on the entire surface was confirmed.

[Comparative Example 12]
Comparative Example 12 was a strawberry that did not form a film.

[Freshness preservation evaluation (strawberry)]
The coated strawberry of Examples 29 and 30 and the strawberry of Comparative Example 12 were evaluated for freshness retention by the weight retention rate.

(Weight maintenance rate)
After storing the coated strawberry of Examples 29 and 30 and the strawberry of Comparative Example 12 at 5 ° C. and 80% RH for 4 days, 7 days and 10 days based on the weight of the strawberry before storage (0 days). Weight retention rate ((weight after storage / weight on 0 days) × 100 (%)) was determined.

Table 10 shows the configurations and evaluation results of Examples 25 to 30 and Comparative Examples 10 to 12.

From Table 10, compared with Examples 25, 27 and 29 in which a film was formed on the whole of avocado, oyster and strawberry, Examples 26, 28 and 30 in which a film was partially formed could shorten the drying time and formed a film. It was confirmed that the efficiency of It is considered that this is because when a film is formed on the entire surface, a liquid pool is formed on the lower surface when the film is allowed to stand, and it takes time to dry the coating film.
Further, even in Examples 26, 28 and 30 in which a film was partially formed, the film was superior to Comparative Examples 10 to 12 in terms of weight retention rate, hardness and color, so that the film was avocado, oyster and strawberry. It was confirmed that the freshness-preserving effect can be obtained even if only a part of the avocado is present.

From the above Test Examples 1 to 4 and Test Examples 7 to 10, it was confirmed that the freshness of the food can be maintained by providing a film containing a sugar-based surfactant on the surface of the food. Then, from Test Example 5, it was confirmed that the film containing the sugar-based surfactant had a high water vapor barrier property, and it was presumed that the freshness of the food was maintained by the high water vapor barrier property of this film. .. Further, from Test Example 6, it can be confirmed that the film containing the sugar-based surfactant has a good oxygen barrier property, and the oxygen barrier property of this film suppresses the respiration of fruits and vegetables and further maintains the freshness of the food. It was speculated that it was. Furthermore, from Test Example 10, it was confirmed that by forming a film only on a part of the food, the freshness of the food can be maintained while increasing the efficiency of the film forming process.
In the present invention, the composition of the coating composition for forming a film is simple, and since it is composed of a sugar-based surfactant that can be used as a food, it has an advantage that it is safe in terms of food hygiene.
Further, in the present invention, since a film is directly applied to the food to impart gas barrier properties, it is not necessary to use a resin packaging film as in the conventional case, and the filmless film can be achieved, which leads to a reduction in the environmental load. It has the advantage of.

1 Food shipping system 10 Food 11 Belt conveyor 12 Rotating roll 13 Immersion tank 14 Drying furnace 15 Evaluation device 16 Shipping vehicle

Claims (27)

A coated food having a coating containing a sugar-based surfactant. The coated food according to claim 1, wherein the sugar-based surfactant is a sucrose fatty acid ester. The coated food according to claim 1 or 2, wherein the lipophilic group of the sugar-based surfactant is a saturated fatty acid. The coating film according to any one of claims 1 to 3, which contains 50% by mass or more of a sugar fatty acid ester having 3 or less fatty acid ester groups when the total amount of the sugar-based surfactant is 100% by mass. Ester with food. The coated food according to any one of claims 1 to 4, wherein the sugar-based surfactant has an HLB of 5 or more. The coated food according to any one of claims 1 to 5, wherein the average film thickness of the coating film is 0.1 μm or more and 10 μm or less. The coated food according to any one of claims 1 to 6, wherein the crystal melting peak temperature of the coating is 40 ° C. or higher and 80 ° C. or lower. The coated food according to any one of claims 1 to 7, wherein the food is a fruit or vegetable. The coated food according to any one of claims 1 to 8, wherein the coating covers only a part of the food. A coating composition containing a sugar-based surfactant and an aqueous solvent. The coating composition according to claim 10, wherein the sugar-based surfactant is a sucrose fatty acid ester. The coating composition according to claim 10 or 11, wherein the lipophilic group of the sugar-based surfactant is a saturated fatty acid. The coating according to any one of claims 10 to 12, which contains 50% by mass or more of a sugar fatty acid ester having 3 or less fatty acid ester groups when the total amount of the sugar-based surfactant is 100% by mass. Composition. The coating composition according to any one of claims 10 to 13, wherein the sugar-based surfactant has an HLB of 5 or more. The coating composition according to any one of claims 10 to 14, wherein the content of the sugar-based surfactant among the non-volatile components in the coating composition is 60% by mass or more. The coating composition according to any one of claims 10 to 15, wherein the water-based solvent is water or alcohol. A film comprising the coating composition according to any one of claims 10 to 16. A method for producing a coated food product, which comprises a step of applying the coating composition according to any one of claims 10 to 16 to a food product, or a step of applying a sugar-based surfactant to a food product without a solvent. The method for producing a coated food product according to claim 18, wherein the coating method is a dipping method or a spraying method. The method for producing a coated food product according to claim 18 or 19, wherein the coating composition or the sugar-based surfactant is applied to a part of the food product. The production of a coated food product according to claim 18 or 19, wherein after applying the coating composition or the sugar-based surfactant to the food, a part of the applied coating composition or the sugar-based surfactant is removed. Method. A film forming method comprising a step of applying the coating composition according to any one of claims 10 to 16 to a food, or a step of applying a sugar-based surfactant to a food without a solvent. The film forming method according to claim 22, wherein the coating method is a dipping method or an injection method. The film-forming method according to claim 22 or 23, wherein the coating composition or the sugar-based surfactant is applied to a part of a food product. The film-forming method according to claim 22 or 23, wherein after applying the coating composition or the sugar-based surfactant to a food, a part of the applied coating composition or the sugar-based surfactant is removed. A method for shipping food, which comprises (A) a step of transporting food, (B) a step of forming a film on the food, and (C) a step of inspecting the coated food using an evaluation device. ) A method for shipping a food product, wherein a film is formed by the method according to any one of claims 22 to 25 in the step. 26. The method of shipping food according to claim 26, wherein the inspection step (C) comprises at least one inspection selected from the group consisting of a visual inspection, a sugar content inspection and a size inspection.

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