WO2019198896A1 - Antibacterial hydrogel for maintaining freshness of food - Google Patents

Abstract

The present invention relates to: an antibacterial hydrogel capable of maintaining the freshness of food, the antibacterial hydrogel using natural polysaccharides so as to be harmless to the human body, having an excellent swelling property so as to be capable of absorbing a large quantity of a liquid to be discharged from food, and having an excellent antibacterial property so as to be capable of effectively reducing microbial growth; and a food storage use thereof. The growth of microorganisms causing food poisoning and spoilage can be effectively inhibited by applying the present invention to food such as meat or seafood, and thus the freshness of food can be maintained at various temperatures such as room temperature, in addition to refrigeration and freezing temperatures, and bacteria can be reduced in a short time by attaching the present invention to meat or seafood for a moment and detaching same therefrom before trimming meat or seafood.

Description

Antimicrobial Hydrogel to Maintain Food Freshness

The present invention relates to an antimicrobial hydrogel for food freshness and a food storage use using the same, and can be effectively inhibited the growth of microorganisms causing food poisoning and decay by applying to foods such as meat or aquatic products to refrigerated and frozen foods. In addition, the present invention relates to an antimicrobial hydrogel that can maintain freshness at various temperatures such as room temperature and can be shortly attached to and detached from meat or aquatic products to reduce bacteria in a short time, and for food storage using the same.

In general, when food, such as meat, aquatic products, vegetables, fruits, etc., the tissue is destroyed, the fluid inside and outside the tissue is leaked to the outside, reducing the freshness of the food, reducing the water holding capacity of the food and self-decomposing food In addition, the growth of bacteria and discoloration on the surface of the food is further accelerated.

Conventionally, in order to maintain the freshness of food for a long time, during food packaging, food surface application products such as moisture absorbing pads are placed between food and containers for packaging the food, and the food is arranged on the upper surface of the product. It separates the spilled liquid from the food and absorbs and stores the liquid discharged from the food more quickly to maintain the freshness of the food for a long time, the food surface application product is a hygroscopic material such as paper, sponge or synthetic polymer It utilizes and utilizes what was manufactured.

However, products made of materials such as paper or sponges seem to completely separate food and liquids spilled from foods, but in reality, it is difficult to maintain food freshness for a long time because they are in contact with each other. In addition, in the case of a product using a hygroscopic polymer, the antimicrobial activity is slightly reduced, the microorganisms causing food poisoning when the food is stored for a long time, the harmful substances to the human body are discharged to the outside There is a need for research on how to compensate for this.

[Preceding technical literature]

(Patent Document 1) Korean Patent Publication No. 10-2003-0086976 (Published Date: 2003.11.12)

(Patent Document 2) Korean Patent Registration No. 10-1678402 (Published Date: 2016.12.06)

(Patent Document 3) Korean Patent Publication No. 10-2016-0038120 (Published Date: 2016.04.07)

(Patent Document 4) Korean Registered Patent No. 10-1012289 (Published Date: 2011.02.10)

The present invention has been made to solve the problems of the prior art as described above, by utilizing natural polysaccharides, harmless to the human body, excellent swelling ability to absorb a large amount of the liquid discharged from food, but also excellent antibacterial growth of microorganisms It is to provide a method for producing a hydrogel that can effectively reduce the, and the technical content for food surface applications that can be stored for a long time food including the hydrogel prepared by the water absorbent material.

In order to achieve the above technical problem, the present invention provides a hydrogel composition for maintaining the freshness of food.

In another aspect, the hydrogel composition may include alginate, agar, glycerol, and calcium chloride.

The present invention comprises the steps of (a) mixing the aqueous solution of calcium chloride to a mixture prepared by mixing alginic acid, agar and glycerol to prepare a hydrogel composition; And (b) forming the hydrogel composition and then drying the hydrogel composition to prepare a hydrogel, wherein the hydrogel composition comprises 1 to 10 parts by weight of alginic acid (alginate), 0.1 to 2, based on 100 parts by weight of the total composition. It provides a method of producing a hydrogel composition comprising a weight part of agar (agar), 30 to 50 parts by weight of glycerol, and 0.05 to 0.5 parts by weight of calcium chloride.

In addition, according to an embodiment of the present invention, in the step (b), it can be dried for 24 to 72 hours at a temperature of 30 to 50 ℃ to prepare the hydrogel.

In addition, according to an embodiment of the present invention, in the step (b), after preparing the hydrogel, the hydrogel is immersed in an aqueous solution containing 0.001 to 1.5% by weight of the antimicrobial material prepared hydrogel Swelling may further comprise a step, the antimicrobial material may comprise natural plant extracts, antimicrobial polymers, metal oxides or mixtures thereof.

In addition, the present invention provides a pad for application to food containing a hydrogel composition for maintaining the freshness.

In the present invention, the pad for application to the food, may be provided in a form that is embedded in the packaging container with food, the hydrogel composition may be provided in a form directly attached to the food. In one example, the pad may be provided in the form of an adhesive cloth or a hygroscopic cloth.

The present invention also provides a food to which the hydrogel is applied.

The present invention also provides a use of the antimicrobial hydrogel composition for maintaining, storing, distributing or storing food freshness.

The present invention also provides a method of using the antimicrobial hydrogel composition to maintain food freshness.

The present invention also provides a method for storing, distributing or storing food using the antimicrobial hydrogel composition.

By including a hydrogel composition for maintaining the freshness of the food according to the present invention, by absorbing a large amount of water flowing out of the food can keep the food and liquid separated from each other can keep the food fresh for a long time.

In addition, according to the method for producing a hydrogel according to the present invention, while producing a hydrogel composition by mixing a natural polysaccharides such as alginic acid, agar, and antimicrobial substances, by molding and drying the composition, while excellent in antimicrobial properties, Hydrogel excellent in hygroscopicity and swelling properties can be produced.

In addition, food surface application products do not emit harmful ingredients to human body, which is excellent in safety, but also has excellent antimicrobial properties, which effectively prevents the growth of bacteria on the surface of food. It can be easily utilized as an absorbent pad or the like.

In addition, the hydrogel according to the present invention can confirm the effect of reducing the bacteria in a short time by attaching and detaching for a while before the meat or aquatic products are groomed.

1 is a real image taken of the hydrogel prepared by the method according to the embodiment.

Figure 2 is a real image of the (a) contact cloth and (b) absorbent fabric containing a hydrogel prepared by the method according to the embodiment.

Figure 3 is the result showing the antimicrobial effect when meat is stored in aerobic state without hydrogel.

4 is a result showing the antimicrobial effect when meat is stored in a vacuum state without a hydrogel.

5 is a result showing the antimicrobial effect when meat is stored in aerobic state attached to the grapefruit seed extract containing hydrogel.

6 is a result showing the antimicrobial effect when the meat is attached to the grapefruit seed extract containing the hydrogel and stored in a vacuum.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is well known and commonly used in the art.

Hereinafter, the present invention will be described in detail.

In one aspect, the present invention relates to a hydrogel composition for maintaining the freshness of food.

Specifically, the present invention is to maintain the freshness of food, in particular, to refrigeration and freezing of food products such as fish, fish, fish, etc. as well as to inhibit the growth of microorganisms at room temperature storage by the hydrogel composition that can maintain the freshness of food longer It is about.

In the present invention, the kind of food applicable is not limited, but includes meat, aquatic products and the like.

In the present invention, the hydrogel composition is directly or indirectly attached to food-carrageenan), a natural polymer such as carboxy methyl cellulose (CMC); Natural copolymers such as xanthan, collagen, chitosan, glucomannan, agar; Includes; Al ^3+, Ca ^{2 +,} the cross-linking agent, such as Na ^+, heat, pH, and salt (CalCl _2), potassium chloride (KCl), glycerol.

In one embodiment of the present invention, it may include alginate, agar, glycerol, calcium chloride, and may include residual water.

Hydrogel composition according to the present invention has the effect of excellent antimicrobial activity, swelling (swelling) ability, excellent flexibility, etc. for maintaining the freshness of food.

In particular, in order to exhibit such an effect, the polymer used; Copolymers; Proper combination of crosslinking agents is also important.

In the present invention, the range of bacteria exhibiting antimicrobial is typically L. monocytogenes , B. cereus , E. coli, etc., according to one embodiment, but not limited to these ranges of bacteria, for example, Salmonella spp., Enteritidis , Pseudomonas spp., Clostridium spp. It shows antimicrobial activity against various bacteria that grow or multiply as the freshness of foods decreases.

In one aspect, the present invention comprises the steps of (a) mixing the alginate (aginate), agar (agar) and glycerol (glycerol) mixture of calcium chloride (CaCl ₂ ) aqueous solution to prepare a hydrogel composition; And (b) molding the hydrogel composition and drying the same to prepare a hydrogel, wherein the hydrogel composition comprises 1 to 10 parts by weight of alginic acid and 0.1 to 2 parts by weight of agar. , 30 to 50 parts by weight of glycerol, 0.05 to 0.5 parts by weight of calcium chloride provides a method for producing an antimicrobial hydrogel, characterized in that it comprises. The remaining parts by weight of the composition may include water.

Step (a) is a step of preparing a hydrogel composition by mixing alginic acid, agar, glycerol, calcium chloride, and optionally water.

Alginic acid included in the hydrogel composition is a natural polysaccharide constituting the cell wall of brown algae and seaweeds, and D-mannuronic acid and L-glucuronic acid are 1,4-glycosidic bonds. Copolymer bonded through (1,4-glycosidic linkage), harmless to the human body, very stable to the digestive system, adsorbs heavy metals by reactivity with metal ions, and inhibits the growth of harmful microorganisms Can play a role.

The alginic acid may play a role of controlling physical properties such as strength, hygroscopicity, and swellability of the hydrogel prepared in the steps to be described later. The higher the content of alginic acid increases the strength of the hydrogel, but the hygroscopicity and swelling property are decreased. Can exhibit characteristics. The alginic acid may be included in a ratio of 1 to 10 parts by weight based on 100 parts by weight of the total hydrogel composition, and when the content of the alginic acid is less than 1 part by weight, it is difficult to sufficiently secure the strength of the hydrogel, and may exceed 10 parts by weight. If the hygroscopicity and swelling is greatly reduced, there is a problem that it is difficult to maintain the unique properties of the hydrogel.

Preferably, the hydrogel composition may be configured to produce a hydrogel having sufficient strength and swellability for use in food packaging, including the alginic acid in a proportion of 5 parts by weight.

The agar is also called agar as a water-soluble natural polymer, and can control physical and structural properties such as pore size, mechanical stiffness, moisture content, and swellability of the hydrogel to be described later by controlling the content of the agar. have. In particular, the hydrogel prepared by mixing the agar may form hydrophilic surface properties, and thus may contain a large amount of water, thereby utilizing the prepared hydrogel as a water absorbing material provided in a food surface application product. It can give a characteristic that can.

Preferably, the agar may be mixed at a ratio of 0.1 to 2 parts by weight based on 100 parts by weight of the total hydrogel composition, and when the content of the agar is less than 0.1 parts by weight, there is a problem in that the strength of the hydrogel to be described later is lowered. If it exceeds 2 parts by weight, the problem of water swelling and hygroscopicity may be lowered when absorbed. More preferably, the agar may be mixed in an amount of 1 part by weight and used for preparing a hydrogel.

The glycerol is added to the hydrogel composition as a polyhydric alcohol to prevent the moisture absorbed in the hydrogel to be described later to dry, prevent the loss of active ingredients such as antibacterial substances added to the hydrogel, and increase the elongation rate in the hydrogel It can play a role. Preferably, the glycerol may be mixed in a proportion of 30 to 50 parts by weight based on 100 parts by weight of the total hydrogel composition, and when the content of the glycerol is less than 30 parts by weight, water may be easily lost in the hydrogel. If the amount exceeds 50 parts by weight, the strength of the hydrogel may be reduced and the stickiness may increase. More preferably, the glycerol may be mixed in a proportion of 40 parts by weight based on a total of 100 parts by weight of the hydrogel composition.

The calcium chloride forms calcium ions in an aqueous solution to induce cation exchange, and the calcium chloride acts as a crosslinking agent to induce crosslinking of alginic acid due to cation exchange, thereby increasing strength and forming a water-soluble gel. This imparts moldability and stability to the hydrogel.

The calcium chloride may be added in an appropriate amount to increase the gel formation ability of the hydrogel by alginic acid to form a hydrogel having suitable hygroscopicity and swellability, preferably the hydrogel composition is a ratio of 0.05 to 0.5 parts by weight of the calcium chloride When mixed at a ratio of more than 0.05 parts by weight, the strength of the hydrogel does not occur, and if it exceeds 0.5 parts by weight, local gelation may occur or non-uniformity may occur due to phase separation. Can be. More preferably, the hydrogel composition may mix the calcium chloride in a proportion of 0.2 parts by weight.

In addition, the calcium chloride is mixed with the aqueous solution of calcium chloride mixed with calcium chloride and water under the condition of continuous stirring so that the mixture is uniformly mixed with agar and glycerol alginate, and the hydrochloric acid having a uniform property by controlling the addition rate of the aqueous solution of calcium chloride Allow gel to form.

In this step, a mixture of alginic acid, agar and glycerol may be prepared to prepare a mixture, and a hydrogel composition may be prepared by mixing an aqueous solution of calcium chloride with the prepared mixture, and the hydrogel composition may be continuously By stirring to ensure that the calcium chloride is uniformly mixed, and when the gelation progresses slowly in the hydrogel composition can be configured to produce a hydrogel by molding in a step to be described later.

The step (b) is a step of forming a hydrogel composition and then drying the hydrogel composition, wherein the hydrogel absorbs a large amount of water as a hydrophilic polymer material having water as a dispersion medium and having a three-dimensional network structure. It is flexible and has excellent adhesion with food and provides a soft texture.

In this step, the hydrogel composition prepared in the above-mentioned step is stirred to induce crosslinking of alginic acid by calcium chloride, and the hydrogel composition is formed on a mold or mold such as a flat plate at the time when the hydrogel composition is gradually hardened and gelled. It can be configured to supply and shape the molded article to be dried by natural drying, hot air drying, vacuum drying method to produce a hydrogel. As described above, when drying is carried out, the water contained in the hydrogel evaporates and alginic acid and agar are completely gelled to form a hydrogel. The drying of such hydrogels influences the properties of the hydrogel to be finally produced. It is one of the main factors.

Specifically, the prepared hydrogel has a higher strength, a higher hygroscopicity, a low hygroscopicity, a low water content, a hard and tough hydrogel, and a low hydrogel has a low strength, high water content, and is soft and soft. Since it is possible to produce a hydrogel, it is possible to produce a hydrogel having physical properties corresponding to the type and degree of hydrogel.

Preferably, in this step, for the production of the hydrogel, after forming the hydrogel composition may be dried for 24 to 72 hours at a temperature of 30 to 50 ℃ to prepare a hydrogel, the hydrogel When less than 24 hours of drying the hydrogel may cause a problem that the water content in the hydrogel is slightly less swelling and hygroscopicity, when drying for more than 72 hours, the moisture absorption rate of the hydrogel is reduced and hardened, the flexibility is reduced Side effects can occur. More preferably, after forming the hydrogel composition, the hydrogel may be prepared by drying at a temperature of 42 ^° C. for 48 hours.

In the present invention, the hydrogel may have an average thickness of 0.5 to 10 mm, when the average thickness of the hydrogel is less than 0.5 mm, the thickness of the hydrogel may be too thin, there is a problem that the mechanical strength falls, 10 mm When exceeding, when the hydrogel absorbs water and swells, there is a problem that the absorption rate decreases and the thickness is too thick, which is not suitable for food packaging, and more preferably, the hydrogel has an average of 1 to 3 mm. It may have a thickness.

In the present invention, the hydrogel is typically, but not limited to, in the form of a sheet such as a patch, film, etc., any size and shape depending on the mold selected.

Further, in this step, in order to improve the antimicrobial power to the hydrogel prepared by the above method, by immersing the prepared hydrogel in an aqueous solution containing an antimicrobial material may be configured to further comprise the step of swelling the hydrogel. Can be.

Specifically, the hydrogel prepared by the method described above has a low water content, exhibits the property of swelling by absorbing water, and absorbs the antimicrobial material into the tissue of the hydrogel by using the swelling property. Improved hydrogels can be prepared.

The antimicrobial material may be an antimicrobial polymer such as chitosan, metal oxides such as titanium dioxide, natural plant extracts such as grapefruit seed extract or citrus extract, and preferably, the antimicrobial material is grapefruit seed extract, citrus extract or Natural antibacterial substances such as mixtures are preferably used to sufficiently absorb the antimicrobial substances that effectively inhibit the growth of various microorganisms in the hydrogel.

In particular, the grapefruit seed extract (grapefruit seed extract) contains a large amount of ascorbic acid, and contains antibacterial materials such as flavonoid compounds, naringin and citral, and generates hydrogen radicals acting as a reducing agent of metal ions to be distributed on the cell membrane By inhibiting the enzymatic activity, the cell membrane function may be weakened, thereby inhibiting the cellular respiration of the microorganism, thereby exhibiting antimicrobial activity. In addition, it has a strong deodorizing power to help eliminate odors and odors.

The grapefruit seed extract may be an extract obtained by extracting the seed with water or ethanol, may be used extracts extracted from various methods other than the above, the grapefruit seed extract as described above is a natural food additive because it is recognized as a hydro It can be used as an antibacterial substance added to the gel.

The citrus extract exhibits antimicrobial activity, including a large amount of ingredients such as limonene, vitamins, flavonoids, essential oils, etc., and can be used in various conventional extracts obtained by extracting tangerine peel of pulp and pulp from citrus fruits with water or ethanol. Since the citrus extracts have also been recognized as safety as natural food additives, they can be added to improve the antimicrobial properties of hydrogels.

In the present step, after the hydrogel is prepared, in the aqueous solution containing the grapefruit seed extract or citrus extract as described above in a proportion (also referred to as wt%) of 0.001 to 1.5 parts by weight based on a total of 100 parts by weight of the hydrogel composition. The prepared hydrogel may be immersed and the hydrogel absorbs water so as to prepare a hydrogel having excellent antimicrobial activity. Hydrogel prepared by immersing in an aqueous solution containing grapefruit seed extract or citrus extract as described above is excellent in antimicrobial activity that inhibits the growth of harmful microorganisms such as Listeria monocytogenes or Bacillus cereus ( Bacillus cereus ) Do.

Preferably, a hydrogel having an antimicrobial activity may be prepared by immersing in an aqueous solution containing grapefruit seed extract or citrus extract in an amount of 1 to 1.5 parts by weight, and such hydrogel may be prepared by L. monocytogenes or B. cereus . It has an excellent antimicrobial activity that completely inhibits the growth of harmful microbial strains.

In addition, preferably, the hydrogel may be immersed in an aqueous solution containing the antimicrobial material for 30 minutes to 4 hours to prepare a hydrogel having excellent antimicrobial properties, and more preferably, the prepared hydrogel Can be immersed for 1-2 hours.

In addition, the hydrogel is immersed in an aqueous solution containing an antimicrobial substance in the same manner as described above to absorb the antimicrobial substance in the hydrogel, and then the hydrogel absorbing the antimicrobial substance is dried for 5 to 1440 minutes so that the hydrogel has excellent antibacterial activity. The gel may be prepared, and the hydrogel prepared in this way may be immediately used as a moisture absorbent capable of absorbing the water flowing out of the food. Preferably, the drying may be performed for 5 to 120 minutes, when the drying time exceeds 120 minutes may cause a problem that the form of the hydrogel is disturbed or antimicrobial rather reduced, if less than 5 minutes water content The problem of too high hygroscopicity may arise.

According to the method for preparing a hydrogel according to the present invention as described above, a hydrogel having excellent antimicrobial properties and excellent hygroscopicity through a simple method of molding and drying a material safe for the human body, such as alginic acid, agar, glycerol, and natural antimicrobial substances. Can be prepared.

In one aspect, the present invention relates to a substrate for direct or indirect application to foods, including the hydrogel (composition).

Specifically, the substrate may take the form of a pad, and is provided with a top film and a bottom film disposed on the top and bottom surfaces of the hydrogel to apply a conventional food surface such as an absorbent pad to absorb moisture from food. It may have various forms that the product has.

For example, the upper film is a fluid permeable film to easily absorb the moisture flowing out of the food, the lower film is a fluid impermeable film to prevent the discharge of water to the food packaging container to maintain the freshness of the food for a long time It can be configured to be, without being limited thereto, may have a variety of forms, such as contact cloth, hygroscopic cloth and the like.

The food surface application product having the above-mentioned form includes a hydrogel prepared by the above method as an absorbent material, and thus has excellent properties such as hygroscopicity and swelling property, so that it can absorb a large amount of water flowing out of the food and liquid. It is possible to prevent the degradation of the freshness of the food by keeping the separated from each other.

In addition, the food surface application product does not discharge harmful ingredients to the human body, while excellent in safety, antimicrobial properties can effectively prevent the growth of bacteria on the food surface between the food and the container for packaging the food packaging. It can be easily utilized as the absorbent pad disposed. It can be easily utilized as an absorbent pad for food packaging for packaging meat, fish, etc. as food, and can be preferably used for packaging materials and packaging containers for meat and fish packaging.

Hydrogel of the present invention in the form of a kind of pack, packaged with an antimicrobial patch (that is, the form of filling the hydrogel inside the absorbent fabric) with the antimicrobial solution in the packaging pack, and the antimicrobial solution until the package is torn out It may be in the form of absorbing or packaging the hydrogel patch and the antimicrobial material (solution) separately.

In one aspect, the present invention relates to a food to which the hydrogel is applied, and such food is not limited to meat, fish, and the like.

In addition, in one aspect, the present invention also relates to the use of the antimicrobial hydrogel composition for food freshness maintenance, storage, distribution or storage.

The present invention also relates to a method of using the antimicrobial hydrogel composition for maintaining food freshness, in one aspect.

The present invention also relates to a method for storing, distributing or storing food using the antimicrobial hydrogel composition.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as being limited by these examples.

EXAMPLES Hydrogel Preparation

In a Erlenmeyer flask containing 5% by weight of alginate and 1% by weight of agar, 40% by weight of glycerol was added and stirred to prepare a mixture. An aqueous calcium chloride solution prepared by mixing 0.2 wt.% CaCl ₂ with water was mixed with the mixture and stirred again to mix. Once the gel was formed, spread the mixture evenly to a square dish in a 0.2 cm thickness for 48 hours in an incubator at 42 ^o C to form a hydrogel (alginate 5% + agar 1% + CaCl ₂ 0.2%) as shown in FIG. + glycerol 40%) was prepared.

As shown in Figure 1, the prepared hydrogel is a odorless transparent gel, combined with a calcium cation to form a hard gel, excellent swelling ability, when swelling antimicrobial material, the gel is weakly dissolved, the size is larger and shrinks when dried It was confirmed to have a property to.

Comparative Example Preparation of General Hydrogel

Except for using 1 wt% κ-carrageenan, 1 wt% xanthan and 40 wt% glycerol, the same procedure as in Example was carried out using a general hydrogel (κ-carrageenan). carrageenan 1% + xanthan 1% + glycerol 40%) was prepared.

Experimental Example 1: MIC analysis of antimicrobial substances

The OD ₆₀₀ of two Gram-positive bacteria [ L. monocytogenes ( B. cereus ) and B. cereus ( B. cereus )] incubated up to the algebraic growth period was set to 0.1 and then placed in all cells of the 96-well plate. 20 μL each was inoculated. To this end, each well was supplied so that 90 μL of the medium, 90 μL of the antimicrobial material, and 20 μL of the bacteria could be included. In the positive control group, 180 μL of the medium except the antimicrobial agent and 20 μL of the bacterium were added. In the negative control group, 90 μL of the antimicrobial agent was added to the medium, and the minimum inhibitory concentration analysis of the antimicrobial agent was performed.

96-well plate was incubated for 24 hours at 30 ^o C by applying the culture conditions of inoculated bacteria. After incubation, L. monocytogenes and B. cereus were stroked in Palcam medium and MYP medium, respectively, and incubated at 30 ^o C. Incubated for 24 hours at and confirmed the minimum inhibitory concentration of the bacteria, the results are shown in Table 1 and Table 2 below.

However, Table 1 shows the minimum inhibitory concentrations of grapefruit seed extracts and citrus extracts for L. monocytogenes , and Table 2 shows the minimum inhibitory concentrations of grapefruit seed extracts and citrus extracts for B. cereus .

Bacterial concentration	Grapefruit Seed Extract	Citrus Extract
7 log CFU / mL	0.002%	0.002%
3 log CFU / mL	0.001%	0.001%

Bacterial concentration	Grapefruit Seed Extract	Citrus Extract
7 log CFU / mL	0.004%	0.004%
3 log CFU / mL	0.001%	0.001%

As shown in Table 1 and Table 2, grapefruit seed extract and citrus extract were found to control high concentrations of L. monocytogenes even at low concentrations of 0.001 to 0.002%, and L. monocytogenes were more effective than B. cereus. In addition, grapefruit seed extract and citrus extract were found to be 0.004% higher than that of L. monocytogenes to control high concentrations (7 log CFU / ml) of B. cereus . It was confirmed that the need for antibacterial substances.

Experimental Example 2: Analysis of antimicrobial effect after mounting antimicrobial substance on hydrogel

(1) Confirmation of inhibitory effect according to exposure time

The hydrogel prepared in Example 1 cut to 1 cm × 1 cm was placed in a 24-well plate containing 1 mL of antimicrobial substance (0.1% grapefruit seed extract, 0.1% citrus extract) for 30 minutes, 2 hours, and 4 hours. The hydrogel was swelled by dipping.

After OD ₆₀₀ of L. monocytogenes cultured up to logarithmic growth period is 0.1, spread the bacterial solution on TSAYE using a sterile cotton swab, and put antibacterial hydrogels with different swelling time on it at 30 ^o C. After incubation for 24 hours, the size of the clear zone (clear zone) was measured, and the antimicrobial activity (species grapefruit seed extract, citrus extract 0.1%) by swelling time of the hydrogel of the Example and the general hydrogel of the comparative example in Table 3 below The confirmed result is shown.

Hydrogel composition	clear zone size (mm)
	Grapefruit Seed Extract 0.1%				Citrus Extract 0.1%
	30 minutes	60 minutes	120 minutes	240 minutes	30 minutes	60 minutes	120 minutes	240 minutes
5% alginate + 1% agar + 0.2% CaCl 2 + 40% glycerol	3.6 ± 0.9	4.0 ± 0.9	4.6 ± 1.1	3.9 ± 0.8	2.3 ± 0.4	2.3 ± 0.4	3.2 ± 0.8	2.7 ± 1.0
1% Κ-carragenan + 1% xanthan + 40% glycerol	1.1 ± 0.5	1.1 ± 0.5	2.1 ± 0.8	1.2 ± 0.7	1.3 ± 0.5	1.4 ± 0.4	2.2 ± 1.0	2.1 ± 0.2

As shown in Table 3, 120 minutes of swelling (swelling) was confirmed that the most antimicrobial effect was higher, and the absorption of more than that was found to decrease the absorption of the antimicrobial material.

Therefore, the swelling time (swelling time) was determined as a condition for absorbing the antimicrobial material 1 to 2 hours well, and then, to produce an antimicrobial hydrogel patch through a swelling time of 2 hours.

(2) inhibitory effect of drying time

After swelling the hydrogel cut to a size of 1 cm × 1 cm for 2 hours, it was dried for 5 minutes, 1 hour, 2 hours, 24 hours at room temperature.

After OD ₆₀₀ of L. monocytogenes incubated to algebraic growth period to 0.1, spread the bacterial solution on TSAYE using a sterile swab, and place antibacterial hydrogels with different drying time on it at 30 ^o C. After incubation for a time, the size of the clear zone was measured, and the results of confirming the antimicrobial activity of the hydrogel (grapefruit seed extract, citrus extract 0.1%) according to the drying time is shown in Table 4 below.

Hydrogel composition	clear zone size (mm)
	Grapefruit Seed Extract 0.1%				Citrus Extract 0.1%
	5 minutes	30 minutes	60 minutes	120 minutes	5 minutes	30 minutes	60 minutes	120 minutes
5% alginate + 1% agar + 0.2% CaCl 2 + 40% glycerol	4.6 ± 1.1	3.0 ± 0.0	2.8 ± 0.5	2.8 ± 1.0	3.0 ± 0.5	3.0 ± 0.7	2.5 ± 1.0	1.3 ± 0.3
1% Κ-carragenan + 1% xanthan + 40% glycerol	2.1 ± 0.8	1.4 ± 0.6	0.7 ± 0.3	0.1 ± 0.0	1.7 ± 0.5	1.0 ± 0.0	0.4 ± 0.1	0.2 ± 0.2

As shown in Table 4, the hydrogel of the example (alginate 5% + agar 1% + CaCl ₂ 0.2% + 40% glycerol) was confirmed to maintain the antimicrobial activity even after 2 hours drying time. The hydrogel of the comparative example (κ-carrageenan 1% + xanthan 1% + 40% glycerol) was confirmed that the antimicrobial activity is sharply inhibited after 2 hours of drying, the fact that the hydrogel of the embodiment can be maintained for a long time Could confirm.

(3) Inhibitory effect by concentration of antimicrobial substance

The prepared gel was cut into 1 cm × 1 cm sized antimicrobial substances at each concentration in a 24-well plate (0.1%, 0.3%, 0.5%, 0.7%, citrus extract 0.1%, 0.3%, 0.5% , 0.7%) for 2 hours, and then dried for 30 minutes at room temperature to determine the antimicrobial activity according to the type and concentration of the antimicrobial material.

After OD ₆₀₀ of two Gram-positive bacteria ( L. monocytogenes , B. cereus ) cultured up to algebraic growth period was set to 0.1, L. monocytogenes was plated on TSAYE and B. cereus on TSA using a sterile swab. After placing the antimicrobial hydrogel prepared in the size of 1 cm × 1 cm above each incubation for 24 hours at 30 ^° C, the growth temperature of the bacteria, the size of the clear zone was measured.

First, the results of confirming the antimicrobial activity of the hydrogels against L. monocytogenes and B. cereus according to the concentration of grapefruit seed extract are shown in Table 5 (wherein * denotes no antimicrobial effect in Table 5 below). ).

Hydrogel composition	clear zone size (radius cm ± SD)
	L. monocytogenes				B. cereus
	Grapefruit Seed Extract
	0.1%	0.3%	0.5%	0.7%	0.1%	0.3%	0.5%	0.7%
5% alginate + 1% agar + 0.2% CaCl 2 + 40% glycerol	0.12 ± 0.13	0.23 ± 0.16	0.33 ± 0.28	0.50 ± 0.00	0.12 ± 0.08	0.18 ± 0.08	0.27 ± 0.08	0.25 ± 0.07
1% Κ-carragenan + 1% xanthan + 40% glycerol	0.05 ± 0.05	0.10 ± 0.11	0.14 ± 0.17	0.30 ± 0.00	0.02 ± 0.04	0.03 ± 0.06	0.03 ± 0.06	-*

As shown in Table 5, the hydrogel of the Example and the hydrogel of the comparative example absorbed grapefruit seed extract showed antimicrobial activity at concentrations of 0.1 to 0.7%, respectively. It could be confirmed that the hydrogel of the Example was more excellent than the hydrogel of the antimicrobial activity against L. monocytogenes and B. cereus in the comparative example.

In particular, the antimicrobial activity against B. cereus showed the highest antimicrobial activity in hydrogels swelled with 0.5% grapefruit seed extract.

In addition, the results of confirming the antimicrobial activity of the hydrogels against L. monocytogenes and B. cereus according to the concentration of citrus extracts are shown in Table 6 (wherein, * denotes no antibacterial effect). .

Hydrogel composition	clear zone size (radius cm ± SD)
	L. monocytogenes				B. cereus
	Citrus Extract
	0.1%	0.3%	0.5%	0.7%	0.1%	0.3%	0.5%	0.7%
5% alginate + 1% agar + 0.2% CaCl 2 + 40% glycerol	0.15 ± 0.10	0.24 ± 0.18	0.34 ± 0.18	0.50 ± 0.00	0.07 ± 0.10	0.16 ± 0.13	0.29 ± 0.16	0.33 ± 0.04
1% Κ-carragenan + 1% xanthan + 40% glycerol	0.07 ± 0.05	0.17 ± 0.17	0.20 ± 0.17	0.30 ± 0.00	0.03 ± 0.06	-*	0.03 ± 0.08	-*

As shown in Table 6, the hydrogel of the example absorbed citrus extract showed an antimicrobial effect at a concentration of 0.1 to 0.7%, the antimicrobial activity was also increased as the concentration of the antimicrobial material increased, hydrogel of the comparative example Rather, the antimicrobial effect exhibited by the hydrogel of the example was more excellent.

The antimicrobial effect against B. cereus was lower than that against L. monocytogenes , but the antimicrobial activity was excellent when swelling the antimicrobial material at 0.5% or higher concentration.

Experimental Example 3: Quantitative Inhibitory Effect of Antibacterial Hydrogel

(1) Confirmation of bacterial growth inhibitory ability of the prepared hydrogel

After OD ₆₀₀ of two gram-positive bacteria cultured up to algebraic growth period became 0.1, L. monocytogenes was plated on TSAYE and B. cereus on TSA using a sterile swab, and was prepared in a size of 2.5 cm × 2.5 cm thereon. One antimicrobial hydrogel was raised and incubated for 24 hours in an incubator at 30 ^o C. After cutting the hydrogel and hydrogel contacted medium, 10 mL of BPW was applied and smeared onto Palcam and MYP media, respectively. The quantitative antimicrobial effect of the hydrogels against L. monocytogenes and B. cereus to confirm the bacterial growth inhibition effect of the prepared hydrogels is shown in Table 7 below. (However, the * notation in Table 7 indicates that the germs are not controlled and grow).

Hydrogel composition	Mean (Log CFU / g) ± SD
	L. monocytogenes			B. cereus
	Control	Grapefruit Seed Extract 0.5%	Citrus Extract 0.5%	Control	Grapefruit Seed Extract 0.5%	Citrus Extract 0.5%
5% alginate + 1% agar + 0.2% CaCl 2 + 40% glycerol	5.3 ± 0.6	-*	-	0.4 ± 0.8	-	-
1% Κ-carragenan + 1% xanthan + 40% glycerol	7.5 ± 1.4	6.5 ± 1.8	5.7 ± 1.8	4.1 ± 0.8	5.3 ± 2.4	3.8 ± 2.5

As shown in Table 7, when the hydrogel was cultured together with the inoculated medium, the ability to inhibit the growth of bacteria was quantitatively confirmed. I could confirm the fact.

In addition, the hydrogel also B which did not contain an antimicrobial material. It was found that it has an effect of inhibiting cereus , which is thought to be an induced effect because the alginate selected in the process of selecting a natural polymer having an antimicrobial effect has a basic antimicrobial activity. It was found that the swelling process absorbed the antimicrobial substances well.

(2) Confirmation of bacteria reduction effect of the prepared hydrogel

After OD ₆₀₀ of two gram-positive bacteria cultured up to algebraic growth period was 0.1, L. monocytogenes was coated with TSAYE and B. cereus was coated with TSA with a sterile swab. ^o Incubated for 24 h in an incubator at C temperature, incubated for 24 hours at 4 ^o C in an antimicrobial hydrogel in medium (8-9 log CFU / g) grown, and then in contact with hydrogel and hydrogel Cut 10 parts of BPW and smear it on Palcam and MYP medium, and quantitatively compare the bacterial count of the hydrogel patch without antimicrobial.The quantitative antimicrobial effect of hydrogel against L. monocytogenes and B. cereus The results of confirming the reduction effect are shown in Table 10 below.

Hydrogel composition	Mean (Log CFU / g) ± SD
	L. monocytogenes			B. cereus
	Control	Grapefruit Seed Extract 0.5%	Citrus Extract 0.5%	Control	Grapefruit Seed Extract 0.5%	Citrus Extract 0.5%
5% alginate + 1% agar + 0.2% CaCl 2 + 40% glycerol	8.9 ± 0.1	4.9 ± 2.0	7.3 ± 0.6	9.3 ± 0.2	1.9 ± 2.2	2.3 ± 1.6
1% Κ-carragenan + 1% xanthan + 40% glycerol	8.8 ± 0.4	8.5 ± 0.1	8.6 ± 0.2	8.8 ± 0.3	8.3 ± 0.4	8.2 ± 0.4

As shown in Table 8, as a result of quantitatively confirming the ability to reduce the bacteria when contacting the antibacterial hydrogel to the site where the bacteria already exist, the hydrogels of the example showed the growth of L. monocytogenes and B. cereus . In particular, in the hydrogel of the Example, when 0.5% citrus extract was added as compared to the normal hydrogel, L. monocytogenes up to 2.5 log CFU / g, and B. cereus up to 7 log CFU / g. When 0.5% of grapefruit seed extract was added, it was confirmed that L. monocytogenes reduced to 4 log CFU / g and B. cereus to 7 log CFU / g.

Experimental Example 4: Check the flexibility and hardness of the antimicrobial hydrogel

Cut into 2 cm × 2 cm and swell the hydrogel for 2 hours in a 24-well plate containing 1 mL of antimicrobial (0.1% grapefruit seed extract, 0.1% citrus extract) to immerse the hydrogel in the gel. ) The antimicrobial hydrogel absorbed by the antimicrobial material was dried for 30 minutes, and then the physical properties (hardness and flexibility) of the hydrogel were measured using a texture analyzer (Stable Micro Systems LTD., Surrey, UK), and Exponent Lite Express software (Stable Micro System LTD) was used to calculate and quantify the hardness and flexibility. As a result, the hardness of the antimicrobial hydrogel was reduced and the flexibility was increased compared to the control gel.

Hydrogel composition	Hardness		flexibility
	Control	2 hours absorption	Control	2 hours absorption
5% alginate + 1% agar + 0.2% CaCl 2 + 40% glycerol	10.9 ± 4.7	5.8 ± 0.2	-0.7 ± 0.4	-0.5 ± 0.2
1% Κ-carragenan + 1% xanthan + 40% glycerol	12.9 ± 4.3	8.7 ± 3.1	-0.3 ± 0.0	-0.2 ± 0.1

Experimental Example 5: Preparation of antibacterial hydrogel patch

Cut the prepared hydrogel into 10 × 10 × 0.2 cm ³ , put it in a square dish, add 0.5% of antimicrobial substance (grapefruit seed extract, tangerine extract) to the degree of gel soaking (50 mL), 2 After swelling at room temperature for an hour to absorb the antimicrobial substance in the hydrogel, the gel swelled in a square dish lid was taken out and dried at room temperature for 30 minutes.

A 17.5 × 13.5 cm ² size cloth was purchased and the antimicrobial hydrogel manufactured by swelling and drying step was attached to the poultice agent of the cloth, and a 10 × 15 cm ² sized cloth was purchased and swelling inside the absorbent cloth. The antimicrobial hydrogel patch was prepared by filling the antimicrobial hydrogel prepared through the drying and drying step, and the hydrogel patch prepared in the form of pars using an adhesive cloth, and the hydrogel patch prepared in the pad form using an absorbent cloth. 2 is shown.

As shown in FIG. 2, the result of fabrication in the form of a parsley using an adhesive cloth was found to have a form similar to that of commercially available pars, and it was judged that there would be no difficulty in producing antibacterial effect by directly contacting livestock products. In addition, as a result of using the absorbent fabric in the form of a pad, it was determined that the antimicrobial material is not in direct contact with the livestock product, thereby minimizing the change in the color, shape, etc. of the livestock product. As antimicrobial substances were applied to livestock products, it was judged that there would be no big problem in the effects of antimicrobial activity.

Experimental Example 6: Antimicrobial Effect Experiment on Meat

(1) antimicrobial effect according to attachment time

The antimicrobial hydrogel patch prepared as described above (in the case of grapefruit extract 1%, citrus extract 1%) was confirmed the antimicrobial effect on the meat. Specifically, the prepared antimicrobial hydrogel (10 × 10 × 0.2 cm ³ ) was attached to the surface of six times (3 cm × 3 cm), and the antibacterial effect was confirmed. L. monocytogenes and Escherichia The antimicrobial effect on coli was confirmed, and when the antimicrobial hydrogel was not attached (control), the hydrogel (5% alginate + 1% agar + 0.2% CaCl ₂ + 40% glycerol) containing no antimicrobial substance ( Gel containing no antimicrobial material), and grapefruit seed extract 1%, compared to the case of the antimicrobial hydrogel prepared by containing 1% citrus extract. As shown in the results below, the bacterial control effect according to the antimicrobial hydrogel patch attachment time was the fastest control effect of L. monocytogenes , and in the case of E. coli , attached grapefruit seed extract In the case of the antimicrobial hydrogel absorbed by 1 min after 1 log CFU / cm ^{2 It} was confirmed that the control effect appeared after 20 minutes.

(1) L. monocytogenes
mean (Log CFU / cm 2 ) ± SD
Time / gel class	Control (no gel)	Hydrogel (No Antibacterial)	Antibacterial Hydrogel (1% Grapefruit Extract)	Antibacterial Hydrogel (1% Citrus Extract)
0 min	3.3 ± 0.1
1 min	3.3 ± 0.2	3.1 ± 0.1	0.9 ± 0.2	0.9 ± 0.2
20 minutes	3.6 ± 0.5	2.4 ± 0.0	1.1 ± 0.4	0.8 ± 0.0
40 mins	3.4 ± 0.1	1.7 ± 0.4	1.4 ± 0.9	1.1 ± 0.4
60 mins	3.2 ± 0.0	2.0 ± 0.4	1.2 ± 0.6	1.2 ± 0.6
(2) Escherichia coli (E. coli)
mean (Log CFU / cm 2 ) ± SD
Time / gel class	Control (no gel)	Hydrogel (No Antibacterial)	Antibacterial Hydrogel (1% Grapefruit Extract)	Antibacterial Hydrogel (1% Citrus Extract)
0 min	2.6 ± 0.2
1 min	2.2 ± 0.0	2.3 ± 0.3	1.5 ± 0.8	2.1 ± 0.6
20 minutes	2.5 ± 0.3	2.5 ± 0.3	1.3 ± 0.0	1.2 ± 0.2
40 mins	2.8 ± 0.2	2.6 ± 0.0	<0.3	1.0 ± 0.0
60 mins	2.3 ± 0.3	2.2 ± 0.3	<0.3	1.0 ± 0.0

(2) Confirmation of hydrogel antimicrobial effect according to storage temperature After the OD ₆₀₀ of L. monocytogenes cultured up to the log growth period was 0.1, 100 μL of L. monocytogenes was cultured on the surface of meat (beef loin, 3 cm × 3 cm) . Monocytogenes were inoculated and the bacteria were spread evenly and stabilized for 10 minutes. Put the antibacterial hydrogel prepared in the size of 2.5cm × 2.5cm on the surface of the inoculated bacteria and stored for 0, 1, 20, 40, 60 minutes at room temperature (25 ℃) or refrigerated (4 ℃), and then hydro The gel was removed to swap a 2.5 cm x 2.5 cm area with a sterile swab. Swab swab was diluted in 10 mL of BPW and smeared on Palcam, L. monocytogenes selective medium, and the antimicrobial effect of normal hydrogel patch without antimicrobial and 0.5% grapefruit and citrus extract were absorbed. The results obtained are shown in Table 12 below.

<After the inoculation of L. monocytogenes and hydrogel attachment, store at room temperature (25 ℃) to confirm hourly>
mean (Log CFU / cm 2 ) ± SD
Time / gel class	Control (no gel)	Hydrogel (No Antibacterial)	Antibacterial Hydrogel (Grapefruit Extract 0.5%)	Antibacterial hydrogel (citrus extract 0.5%)
0 min	3.8 ± 0.5
1 min	3.9 ± 0.2	4.1 ± 0.5	0.8 ± 0.7	1.3 ± 1.0
20 minutes	3.8 ± 0.1	4.0 ± 0.3	1.2 ± 0.6	0.8 ± 0.7
40 mins	3.6 ± 0.1	4.0 ± 0.3	1.1 ± 0.1	0.8 ± 0.8
60 mins	3.4 ± 0.6	3.7 ± 0.4	0.7 ± 0.5	0.6 ± 0.2

<After inoculation of L. monocytogenes and hydrogel attachment, refrigerated (4 ℃) for time confirmation
mean (Log CFU / cm 2 ) ± SD
time	Control (no gel)	Hydrogel (No Antibacterial)	Antibacterial Hydrogel (Grapefruit Extract 0.5%)	Antibacterial hydrogel (citrus extract 0.5%)
0 min	4.0 ± 0.1
1 min	3.8 ± 0.1	4.1 ± 0.1	1.3 ± 0.1	2.2 ± 0.4
20 minutes	3.7 ± 0.1	4.0 ± 0.3	0.7 ± 0.6	1.1 ± 0.7
40 mins	3.9 ± 0.2	3.8 ± 0.4	0.7 ± 1.0	1.2 ± 0.7
60 mins	3.8 ± 0.3	3.9 ± 0.1	1.0 ± 0.4	0.8 ± 0.6

(3) Check the meat color change

In addition, the color change of the meat was measured. In general, it is reported that the color difference index (ΔE) can recognize the color difference at about 5-6 points, and only 3 trained persons can recognize the color difference at 3-6 points (Yun et al. ., 2015). As a result of attaching the hydrogel patch to the meat and checking the color difference index up to 1 hour, the change in the color difference index was hardly recognized until 20-40 minutes with the hydrogel attached (Table 13).

		△ E (color difference index, )
time	Control (no gel)	Hydrogel (No Antibacterial)	Antibacterial Hydrogel (1% Grapefruit Extract)	Antibacterial Hydrogel (1% Citrus Extract)
0 min	1.0 ± 0.3
20 minutes	0.7 ± 0.1	4.1 ± 0.6	2.0 ± 1.1	2.3 ± 0.3
40 mins	2.7 ± 0.9	4.1 ± 1.6	3.7 ± 1.4	4.7 ± 1.1
60 mins	4.8 ± 1.1	4.8 ± 1.9	5.1 ± 1.0	3.5 ± 0.7

(4) Comparison of spraying method and hydrogel patch and antibacterial effect

In addition, the antimicrobial effect of the method of spraying the antimicrobial material and the method of attaching the hydrogel was examined. Compared to the case of spraying a 1% grapefruit extract-containing solution (containing 1% grapefruit extract in sterilized distilled water) and attaching a previously prepared hydrogel-containing hydrogel, the antibacterial effect when applied with a hydrogel was compared to the spraying method. It was confirmed that the effect and retention period were longer.

mean (Log CFU / cm 2 ) ± SD
Time / gel class	Control (no gel)	Hydrogel (No Antibacterial)	Grapefruit Extract (spray)	Grapefruit Extract Hydrogel
0 min	3.7 ± 0.3
1 min	2.9 ± 0.1	2.8 ± 0.3	2.7 ± 0.4	1.7 ± 0.1
20 minutes	3.0 ± 0.2	3.5 ± 0.1	2.5 ± 0.7	1.4 ± 0.6
40 mins	2.8 ± 0.1	3.0 ± 0.3	3.5 ± 0.0	<1.0
60 mins	2.9 ± 0.3	2.8 ± 0.0	2.2 ± 0.0	<1.0

(4) Comparison of antimicrobial effect in vacuum packaging and aerobic state

In addition, looking at the results of comparing the antimicrobial effect in the vacuum packaging and aerobic state, when stored in a vacuum package than when stored in aerobic bacteria can be easily controlled (Fig. 3 and 4), especially containing grapefruit extract When vacuum packaging after attaching the hydrogel it was confirmed that the L. monocytogenes is completely controlled (Fig. 5 and 6).

(5) sensory evaluation

In addition, the meat (slicing meat, 2 cm × 2 cm) was attached to the antimicrobial hydrogel (10 × 10 × 0.2 cm ³ ) prepared in Example for 20 minutes and subjected to sensory evaluation. The overall acceptability was judged based on appearance, odor, odor, flavor, year, and succulent items, and there was no significant difference for each experimental group. It was confirmed that the overall acceptability was high due to the positive effect.

	Exterior	incense	zest	year	Succulent	Comprehensive Symbol Map
Control (no gel)	5.1	5.3	4.8	5.5	4.7	5.1
Hydrogel (No Antibacterial)	6.4	5.0	4.5	6.3	5.8	5.6
Grapefruit hydrogel	6.4	5.8	5.0	7.1	5.9	6.0
Citrus Hydrogel	5.3	5.9	5.4	6.0	4.9	5.5

Experimental Example 7: Antimicrobial effect experiment on aquatic products

Vibrio parahaemolyticus was inoculated in 1.0 ± 0.5 g of flounder to confirm the antimicrobial effect.

V. parahaemolyticus (ATCC17802, ATCC27519, ATCC33844, ATCC43996) was incubated in TCBS (thiosulfate citrate bile salt sucrose agar) to identify colonies. After that, 100 μL of the culture medium was inoculated on the surface of 1.0 ± 0.5 g of sliced raw flatfich and stabilized for 10 minutes. Put an antimicrobial hydrogel prepared in 2 cm × 2 cm size on the surface of the flatfish sashimi inoculated with bacteria and stored for 0, 1, 20, 40, 60 minutes at refrigeration (4 ^o C) temperature, then remove the hydrogel A 2 cm × 2 cm area was swapped with a sterile swab. Diluted with a cotton swab to swap BPW 10 mL of V. parahaemolyticus were each plated on selection medium which TCBS (thiosulfate citrate bile salt sucrose agar), a general hydrogel patch and 1% grapefruit, tangerine extract did not apply the antimicrobial material each The results of confirming the antimicrobial effect of the absorbed antimicrobial hydrogel patch are shown in Table 16 below. One minute after attachment of the antimicrobial hydrogel, it showed antimicrobial effect against V. parahaemolyticus , and it was confirmed that the effect of more than 2 log CFU / cm ² compared to the control group without the gel.

mean (Log CFU / cm 2 ) ± SD
Time / gel class	Control (no gel)	Hydrogel (No Antibacterial)	Antibacterial Hydrogel (1% Grapefruit Extract)	Antibacterial Hydrogel (1% Citrus Extract)
0 min	2.7 ± 0.0
1 min	3.0 ± 0.0	2.5 ± 0.0	1.3 ± 0.5	1.1 ± 0.5
20 minutes	3.3 ± 0.0	2.6 ± 0.1	1.3 ± 0.1	1.2 ± 0.5
40 mins	3.3 ± 0.0	2.6 ± 0.0	1.1 ± 0.3	1.3 ± 0.2
60 mins	2.9 ± 0.3	2.5 ± 0.0	1.2 ± 0.6	0.5 ± 0.5

The specific parts of the present invention have been described in detail above, and for those skilled in the art, these specific descriptions are merely preferred embodiments, and the scope of the present invention is not limited thereto. Will be obvious. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (12)

1. Antimicrobial hydrogel composition for maintaining the freshness of food.
2. The method of claim 1,

   The antimicrobial hydrogel composition is characterized in that it comprises an antimicrobial material.
3. The method of claim 2,

   The antimicrobial composition is characterized in that it comprises one or more selected from the group consisting of natural plant extracts, antimicrobial polymers and metal oxides.
4. The method of claim 1,

   The antimicrobial hydrogel composition is characterized in that it comprises an alginate, agar, glycerol, calcium chloride, and an antimicrobial substance.
5. Substrate for application to food containing an antimicrobial hydrogel composition according to claim 1.
6. The method of claim 5,

   And the substrate is in the form of a pad or a film adhered to a food surface or a container for storing food.
7. The method of claim 6,

   The substrate is characterized in that the form of the contact cloth or absorbent cloth.
8. Food or food packaging material to which the antimicrobial hydrogel composition according to claim 1 is applied.
9. A method for preparing an antimicrobial hydrogel composition according to claim 1, comprising the following steps:

   (a) preparing a hydrogel composition by mixing an aqueous solution of calcium chloride (CaCl ₂ ) with a mixture prepared by mixing alginate, agar, and glycerol; And

   (b) forming the hydrogel composition and then drying to prepare a hydrogel;

   Wherein the hydrogel composition comprises 1 to 10 parts by weight of alginic acid, 0.1 to 2 parts by weight of agar, 30 to 50 parts by weight of glycerol, and 0.05 to 0.5 parts by weight of calcium chloride based on 100 parts by weight of the total composition.
10. Use of the antimicrobial hydrogel composition according to claim 1 for maintaining food freshness
11. A method of using the antimicrobial hydrogel composition according to claim 1 for maintaining food freshness.
12. A method for storing, distributing or storing food using the antimicrobial hydrogel composition of claim 1.

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