JP2008079569A - Freshness-keeping sheet for vegetables, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a freshness-keeping sheet for vegetables, which has soft and wet feeling, is capable of effectively preventing lowering of freshness of vegetables, and to provide a method for producing the freshness-keeping sheet. <P>SOLUTION: This freshness-keeping sheet for vegetables includes a fiber web 5 which is excellent in water absorption and water retention, such as paper towel and kitchen paper, and has pulp of natural fiber or regenerated fiber as a main raw material, which has a basis weight of 10-50 g/m<SP>2</SP>, a thickness of 0.1-0.25 mm, and ruggedness on the surface. The freshness-keeping sheet has the fiber web as the support medium, and trehalose is supported by the support medium. The method for producing the freshness-keeping sheet is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a freshness-keeping sheet for vegetables and a method for producing the same, and more specifically to a freshness-holding sheet for vegetables obtained by supporting trehalose on a fiber web having irregularities and a method for producing the same.

Foods such as marine products, livestock products, agricultural products, processed foods, etc. will decay and oxidize over time, and the freshness will deteriorate.In particular, vegetables will be metabolized in the body after harvest, and they will decay due to respiration and transpiration. There was a problem that it was easy to proceed.
As a method for maintaining the freshness of vegetables, a method such as bringing a freshness-keeping agent into direct contact with vegetables is also known, but there are also problems such as taking time and effort to dilute with water, and the freshness-keeping agent is expensive. There was also a problem in terms of economy. Moreover, in general households, the situation is that they are stored in a refrigerator by wrapping with newspaper or using a wrap film, and the development of a freshness-keeping material for new vegetables has been desired.

Trehalose is known as one that is effective in maintaining and protecting the freshness of food tissues (Non-patent Document 1: Food and Development, VOL.33 No. 11 [Volume 489]).
As a technique for maintaining freshness using trehalose, JP-A-9-252719 (Patent Document 1), JP-A-6-227904 (Patent Document 2), JP-A 2000-4778 (Patent Document 3). and so on.

JP-A-9-252719 contains 0.8 to 1.5% by mass of ethyl alcohol, 0.1 to 5% by mass of trehalose, and 0.005 to 0.3% by mass of vitamin Cs. There is disclosed a method for maintaining the freshness of cut vegetables, characterized in that vegetables cut into an appropriate size are brought into contact with an aqueous solution.
JP-A-6-227904 discloses a freshness-preserving agent for cut flowers and leaf vegetables containing trehalose as an active ingredient, that is, a freshness-preserving agent having a trehalose content of 0.001 to 3% by mass. Yes.
These JP-A-9-252719 and JP-A-6-227904 are basically of the type that is applied to target vegetables and cut flowers by spraying.
JP 2000-4778 discloses a fresh food preservation solution containing trehalose as an active ingredient, wherein the concentration of trehalose is 10 to 2000 mM / L, and the concentration of the extract extracted from garlic is 0.001 to 200 g / L. This is a type in which a food product is directly immersed in a fresh food preservation solution.

Prior art relating to a sheet-like food packaging material having a freshness-keeping effect includes JP-A-6-158500 (Patent Document 4), JP-A-9-172952 (Patent Document 5), and JP-A-11-117193. (Patent Document 6), JP-A 2000-270764) and Patent Document 7).
Japanese Patent Laid-Open No. 6-158500 discloses a freshness-holding sheet made of a non-woven fabric containing superabsorbent fibers, and Japanese Patent Laid-Open No. 9-172952 discloses a freshness-holding sheet in which a silver zeolite dispersion is applied to a non-woven fabric. Yes.
Japanese Patent Application Laid-Open No. 11-117193 discloses a fresh vegetable freshness-keeping sheet in which a grapefruit seed extract is contained in paper, which prevents a decrease in freshness by sticking to a cut end of vegetables. is there.
The freshness-keeping material described in Japanese Patent Application Laid-Open No. 2000-270764 is obtained by integrating a superabsorbent resin with a base material selected from nonwoven fabric, woven fabric, paper, porous material, net-like material, film, and sheet. A water retention layer and a hydrophilic layer selected from the group consisting of a soft porous material, a semi-rigid porous material, and a fibrous material laminate are laminated.

Regarding inclusion of trehalose in the support, inclusion in a film in JP-A-2000-239454 (Patent Document 8) or inclusion in a fiber web in JP-A-2003-20593 (Patent Document 9) Is disclosed.
Japanese Patent Application Laid-Open No. 2000-239454 discloses a method for maintaining the freshness of a food by forming a film from a polyolefin-based composition containing an olefin polymer as a base polymer, trehalose and an inorganic filler, and packaging or containing the food. A method is disclosed.
Japanese Patent Application Laid-Open No. 2003-20593 discloses a fiber web product containing a sugar alcohol containing at least one of xylitol, erythritol, mannitol, lactitol, and sorbitol.

JP-A-9-252719 JP-A-6-227904 Japanese Patent Laid-Open No. 2000-4778 Japanese Patent Laid-Open No. 06-158500 JP 09-172952 A JP 11-117193 A JP 2000-270764 A JP 2000-239454 A JP 2003-20593 A Food and Development, VOL.33 No.11 (Vol.489)

  The present invention has been made in view of the above problems, and its object is to replace the conventionally known freshness-keeping method, a novel, soft and moist vegetable freshness-keeping sheet and a method for producing the same Is to provide.

As a result of intensive studies, the present inventors have found that the use of a sheet in which a freshness maintaining agent containing trehalose as an active ingredient is carried on a flexible fiber web can effectively prevent a decrease in freshness of vegetables. I found it.
That is, by using a flexible fiber web with excellent water absorption and water retention properties such as paper towels and kitchen paper as a support and combining it with trehalose which has water absorption and water retention properties but is not hygroscopic, the freshness of vegetables The present inventors have found that a suitable environment can be formed for maintaining the temperature and have reached the present invention.
The present invention is basically an invention relating to a vegetable freshness-holding sheet in which trehalose is supported on a fiber web, and includes the following inventions.

(1) A fiber web mainly composed of natural fiber or recycled fiber pulp, having a basis weight of 9 to 50 g / m ² , a thickness of 0.1 to 0.25 mm, and a surface having irregularities on the surface. And a freshness-keeping sheet for vegetables, wherein trehalose is supported on the support.

(2) The vegetable freshness-keeping sheet according to (1), wherein the fiber web as a support is crepe paper.

(3) The freshness-keeping sheet for vegetables according to (1), wherein the fiber web serving as a support is embossed.

(4) support, there is a fibrous web is a basis weight of 4.5~25g / ^{m 2} was laminated at least two, that the basis weight of the laminated state is a fibrous web 9~50g / ^{m 2} The freshness-keeping sheet for vegetables according to any one of (1) to (3).

(5) trehalose, vegetables according to any one of characterized in that it is 0.1g ^{/ m 2} ~1.0g ^/ m 2 bearing against the support (1) to (4) freshness Holding sheet.

(6) The freshness-keeping sheet for vegetables according to any one of (1) to (5), wherein trehalose is contained in a binder used for laminating fiber webs.

(7) Trehalose is obtained after creping a support made of a fiber web having a basis weight of 9 to 50 g / m ² and a thickness of 0.1 to 0.25 mm using pulp of natural fiber or recycled fiber as a main raw material. The method for producing a vegetable freshness maintaining sheet according to (1), wherein the blended solution is applied to the support.

(8) A fiber web having a basis weight of 9 to 50 g / m ² and a thickness of 0.1 to 0.25 mm mainly composed of natural fiber or recycled fiber pulp, and coated with a solution containing trehalose; Unevenness is formed on the surface using an embossing roll, The method for producing a freshness-keeping sheet for vegetables according to (1).

(9) At least two fiber webs having a basis weight of 4.5 to 25 g / m ² are laminated, and a polyvinyl alcohol solution containing trehalose is applied as a binder to the lamination surface of the fiber web, and the basis weight in the laminated state. A method for producing a freshness-keeping sheet for vegetables according to (7) or (8), wherein a support comprising a fiber web of 9 to 50 g / m ² is prepared.

(10) The method for producing a freshness-keeping sheet for vegetables according to (9), wherein the binder is a solution in which 30 to 50 parts by mass of trehalose is blended with 100 parts by mass of polyvinyl alcohol.

  The freshness-keeping sheet for vegetables according to the present invention is obtained by supporting trehalose on a fiber web, which is a packaging material having irregularities, so that when the vegetables are wrapped, the convex portion, that is, the trehalose present at the place in contact with the vegetables. Moisture can be gently moved from the vegetables to the fiber web side by the water retention. In addition, due to the non-hygroscopicity of trehalose, the space in the recess is kept at a high humidity, and the evaporation of moisture from vegetables can be suppressed.

Therefore, the water absorption and retention of the fiber web and trehalose can absorb excess moisture, so that the increase of bacteria can be suppressed and the space where the vegetables are wrapped can be kept at high humidity. It is possible to provide a packaging material that can suppress the transpiration of moisture from the vegetable and prevent the tissue of the cut surface of the vegetables from hardening and has an excellent effect of maintaining freshness.
Moreover, since trehalose is a food material, the freshness-keeping sheet of the present invention has no problem from the viewpoint of safety.

  Next, based on the embodiment of the present invention, the freshness-keeping sheet for vegetables of the present invention and the method for producing the same will be described in detail.

<About trehalose>
The trehalose used in the present invention is a non-reducing saccharide in which two glucose molecules are linked by α, α-1,1, and does not cause browning (Maillard reaction) even when heated in the presence of amino acids and proteins. It is also known that it is effective in preventing starch aging. The effect is to maintain the freshness of the food tissue. Trehalose has the ability to denature due to heating, overheating, freezing, crushing, pressurization during processing, deterioration due to environmental (temperature, humidity, etc.) changes, and general changes over time. It is known that it has an action of maintaining and maintaining the original state.

<About fiber web>
As the fiber web used in the present invention, what is called a paper towel or kitchen paper manufactured using pulp fiber as a main raw material as a substitute for towels and towels is preferably used, particularly natural pulp fiber and recycled fiber. And those composed of one or more raw materials selected from the group of rayon.
The basis weight of the fibrous web, in 4.5~25g / ^{m 2} per one, preferably one per 5~24g / ^{m 2,} the two-ply in 9~50g / ^{m 2,} preferably 2 It is 10 to 48 g / m < ² > by stacking. The thickness is preferably 0.1 to 0.25 mm.

The fiber web preferably used as a support in the present invention has a basis weight defined by JIS S3104 of 10 to 50 g / m ² in a two-layer stack, thickness (JIS P8118 test condition: temperature 20 ± 2 ° C., Humidity 65 ± 2% (measured with a hybrid test machine) is 0.1 to 0.25 mm, density is 0.120 to 0.300 g / cm ³ (JIS P8118 test conditions: temperature 20 ± 2 ° C., humidity) 65 ± 2%), tensile strength is 4.8 N or more in the vertical condition when dry as defined in JIS S3104, 1.9 N or more in the horizontal condition when dry, and 1.3 N or more in the vertical condition when wet The water absorption specified by the dropping method water absorption of JIS S3104 is 8 seconds or less, the whiteness specified by JIS S3104 is 79% or more, and the crepe rate is 18 to 25%.
The crepe rate is expressed as 100 × (dryer peripheral speed−winding part peripheral speed) / winding part peripheral speed. For example, the peripheral speed of the dryer part is 1600 m / min. If the peripheral speed is 1314 m / min, the crepe rate of the fiber web obtained from the above equation is about 22%.

  The raw material of the fiber web is selected from, for example, wood pulp, non-wood pulp, synthetic pulp, waste paper pulp, and the like as the pulp fiber (raw pulp). Specifically, chemicals such as kraft pulp (KP) such as hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), soda pulp (AP), sulfite pulp (SP), dissolved pulp (DP), etc. Pulp (CP) Groundwood pulp (GP), Stone Grand Pulp (SGP), Refiner Grand Pulp (RGP), Pressurized Ground Wood Pulp (PGW), Thermomechanical Pulp (TMP), Chemithermomechanical Pulp (CTMP), Bleach Chemi Thermo Mechanical pulp (MP) such as mechanical pulp (BCTMP), chemical mechanical pulp (CGP), semi-chemical pulp (SCP), synthetic pulp made from nylon, rayon, polyester, polyvinyl alcohol (PVA), etc., deinking Waste paper pulp such as pulp (DIP) and waist pulp (WP) (TP), cotton (cotton), flax pulp, straw pulp, esparto pulp, bagasse pulp, bamboo pulp, kenaf pulp, bast pulp, buff pulp made from flax, hemp, jute, manila hemp, ramie, etc. One or several kinds of auxiliary pulps such as these can be appropriately selected and used. Preferred pulps are hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP) from the viewpoints of stable supply, economical viewpoint, and mass production.

  These pulps are preferably so-called TCF pulps bleached using oxygen, ozone, hydrogen peroxide, and in some cases may be ECF pulps including chlorine dioxide bleaching.

  The fiber web which is a support in the present invention has a surface with irregularities. As the fiber web having irregularities on the surface, those obtained by creping or embossing are preferable.

  Regarding embossing, it is needless to say that three known embossing methods such as the mated steel (regular) method, the nested method, and the pillow method described in “Latest Paper Processing Handbook”, pages 893-898 are applied. .

<About the binder>
The binder (binder) used in the lamination and embossing process is usually a water-soluble polymer compound.
Specific examples of the aqueous polymer compound include, for example, complete (partially) saponified polyvinyl alcohol (PVA), carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, diacetone group-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, hydroxyethyl cellulose, Methyl cellulose (MC), carboxymethyl cellulose (CMC), starch and derivatives thereof, alginic acid (salt), xanthan gum, rhamzan gum, welan gum casein, diisobutylene / maleic anhydride copolymer salt, styrene-maleic anhydride copolymer salt, Examples include ethylene-acrylic acid copolymer salts and styrene / acrylic acid copolymer salts. Of these, complete (partially) saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, diacetone group-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, and the like are preferred, and particularly, completely (partially unmodified) ) Saponified polyvinyl alcohol is preferable because of its excellent pot life.

Of course, these water-based polymer compounds may be used in combination of two or more if necessary, and further, as long as the desired effect of the present invention is not impaired, styrene / butadiene latex, acrylic latex, polyester polyurethane type. A water-dispersible polymer compound such as latex can also be used in the coating liquid.
As the aqueous polymer compound, polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) is preferably used from the viewpoint of hygiene. The polymerization degree is preferably 1400 to 1800 on average and the saponification degree is 99.5%. PVA solution applied to the fiber web is usually 0.8 g / ^{m 2.} Needless to say, the coating amount is appropriately determined according to the physical properties of the target product.

  The trehalose blended in the PVA solution is 30 to 50 parts by mass, preferably 32 to 48 parts by mass, and more preferably 35 to 45 parts by mass with respect to 100 parts by mass of PVA. However, a stirrer is required for storage.

When using a fiber web loaded with trehalose as a freshness-keeping sheet for vegetables, wrap the vegetables with the fiber web (freshness-holding sheet) and store in a refrigerator so that a high-humidity space is formed. To do. In that case, the freshness-keeping sheet can be brought into partial contact with the vegetables at the convex portions formed on the surface, and the moisture can be moved gently by the water-retaining power of trehalose. Further, due to the non-hygroscopicity of trehalose, a high-humidity space is formed in the recesses on the surface of the fiber web, and the evaporation of moisture from vegetables can be suppressed.
Moreover, when it preserve | saves in the environment of high humidity called the vegetable room of a refrigerator, it can maintain at higher humidity and is preferable.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the examples and comparative examples, the mass is shown as solid mass.

The fiber web was manufactured by the process shown in FIG. In FIG. 1, 1 is a wire part, 2 is a press part, 3 is a Yankee dryer, 4 is a creping doctor, and 5 is a fiber web.
As raw material pulp, hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP) were used. Beat the Canadian standard freeness of the blended pulp to 620-630 ml CSF, and add 0.15% polyamide polyamine epichlorohydrin modified wet paper strength enhancer (Arakawa Chemical Industries, Ltd., trade name: Arafix 255) to the pulp Then, the LBKP layer and the NBKP layer were combined with a twin-wire type two-layer yankee paper machine, dried so that the LBKP layer was in contact with the mirror surface of the Yankee dryer, and the basis weight was 20 A fiber web having a weight ratio of 0.5 g / m ² , LBKP and NBKP and an absolute dry amount of 60 parts: 40 parts was produced. The obtained fiber web is peeled off from the dryer surface by the creping doctor 4, and a speed difference is provided to the take-up reel to give 18% dry crepe, and the LBKP layer in contact with the mirror surface of the Yankee dryer 3 is outside. It wound up so that it might become, and was set as the fiber web 5. FIG.

Trehalose was applied to the fiber web by the process of FIG. In FIG. 2, 5 and 6 are fiber webs, 7 is a coater for trehalose coating, and 8 is a trehalose-supporting fiber web in which two sheets are stacked.
In this example, a fiber web having a basis weight of 20.5 g / m ² was used.
The fiber webs 5 and 6 were overlapped so that the NBKP layers were inside, and then the aqueous solution containing trehalose was applied by the coating coater 7 to obtain a double-layer trehalose-supporting fiber web 8. .

  The trehalose aqueous solution for coating is 40% by mass of trehalose (registered trademark Treha, manufactured by Hayashibara), 40% by mass of water, PVA (trade name JHL-121-52-D, manufactured by Nippon Fuller) or 20% of starch as a binder. A coating solution was used.

Next, the trehalose-carrying fiber web 8 was embossed by the process of FIG. 3 to obtain a final product. 9 is a steel embossing roll, and after embossing, a folding, cutting, and boxing process 10 was performed to obtain a freshness-holding sheet.
The resulting basis weight of freshness sheet 41.9 g / ^{m 2} der Li, supported content trehalose was 0.7 g / ^{m 2.}

The following method can also be employed as another method for supporting trehalose.
In FIG. 4, 11 is a web A, 12 is a web B, 13 is an upper nip roll, 14 is an upper embossing roll, 15 is a lower embossing roll, 16 is a lower nip roll, 17 is a marriage roll, 18 is a fountain roll, 19 is a transfer roll, 20 is an applicator roll, 21 is a group pan, and 22 is a dancer roll. The group bread 21 is supplied with PVA (trade name JHL-121-52-D, manufactured by Nippon Fuller), and 40 trehalose (registered trademark Treha, manufactured by Hayashibara) with respect to 100 parts by mass of the PVA in the group bread 21. Part by mass is blended. When the web A and the web B are laminated at the nip between the upper embossing roll 14 and the lower embossing roll 15, the PVA solution picked up from the fountain roll 18 is transferred to the web A in the group pan 21, the transfer roll 19, and the applicator roll 20. The basis weight of the resulting fiber web 2-ply product that is transferred and laminated with the PVA solution transferred to the web A in the lower embossing roll 15 is 41.3 g / m ^2, and the supported content of trehalose is 0.00. It was 13 g / m ² .

The trehalose-carrying fiber web 2-ply product obtained by the method of FIGS. 1 to 3 was cut (20 cm × 20 cm) to obtain a test piece. It is attached to two samples of the upper radish and the lower part of the radish, wrapped in this test piece, stored in a vegetable room in a refrigerator, 6-7 ° C., and 90% humidity. The storage days for the trehalose-supported fiber web and the trehalose-non-supported fiber web are 7 The daily mass change was measured. The results are shown in Tables 1 and 2.
Similarly, Tables 3 and 4 show the mass change measurement results when spinach and celery were used as test pieces.

Upper radish blue neck

Lower radish

spinach

celery

<Evaluation>
As is clear from Tables 1 to 4, the mass change can be sufficiently suppressed in the storage for 7 days, and the effect of the trehalose-supported fiber web is obvious.
The test area vegetables wrapped with the trehalose-carrying fiber web keeps the cut surface fresh and the skin remains soft, while the control product (wrapped with the trehalose non-carrying fiber web) cuts. The surface was dried to form a film, and the epidermis was dry and hard.

  The same test was carried out on cabbage (6-7 ° C.), tomato, shiitake mushroom, onion, lettuce, broccoli, cucumber, carrot (6-7 ° C., humidity 70-75%). I was able to confirm.

  The freshness-holding sheet comprising the trehalose-supported fiber web according to the present invention has an excellent freshness-keeping effect, so it can prevent the occurrence of spoilage and mold that occur during long-term storage and long-distance transportation of fruits and vegetables, Since it is possible to maintain a hygienic state, it can make a great contribution to producers and transporters who handle fresh food in various fields, which is extremely useful in the industry.

Fiber web manufacturing process diagram Trehalose coating process diagram Embossing process diagram Other trehalose loading process diagram

Explanation of symbols

1: Wire part 2: Press part 3: Yankee dryer 4: Creping doctor 5, 6: Fiber web 7: Coat for trehalose coating 8: Trehalose-supporting fiber web 2-ply 9: Steel embossing roll 10: Folding machine and cutting・ Packaging process 11: Web A
12: Web B
13: Upper nip roll 14: Upper embossing roll 15: Lower embossing roll 16: Lower nip roll 17: Marriage roll 18: Fountain roll 19: Transfer roll 20: Applicator roll 21: Group pan 22: Dancer roll

Claims (10)

Trehalose, which is a fiber web mainly composed of natural fiber or recycled fiber pulp, having a basis weight of 9 to 50 g / m ² , a thickness of 0.1 to 0.25 mm, and a surface having irregularities on the surface. Is supported on the support. A freshness-keeping sheet for vegetables.   2. The freshness-keeping sheet for vegetables according to claim 1, wherein the fiber web serving as a support is crepe paper.   2. The freshness-keeping sheet for vegetables according to claim 1, wherein the fiber web serving as a support is embossed. Support, there is a fibrous web is a basis weight of 4.5~25g / ^{m 2} was laminated at least two, and wherein the basis weight of the laminated state is a fibrous web 9~50g / ^{m 2} The freshness preservation sheet for vegetables according to any one of claims 1 to 3. Trehalose, vegetables freshness sheet according to any of claims 1 to 4, characterized in that it is 0.1g ^{/ m 2} ~1.0g ^/ m 2 bearing against the support.   Trehalose is contained in the binder used for lamination | stacking of a fiber web, The freshness maintenance sheet | seat of vegetables in any one of Claims 1-5 characterized by the above-mentioned. A solution in which trehalose is blended with a support obtained by creping a fiber web having a basis weight of 9 to 50 g / m ² and a thickness of 0.1 to 0.25 mm, which is mainly made of natural fiber or recycled fiber pulp. The method for producing a freshness-keeping sheet for vegetables according to claim 1, wherein the method is applied to the support. An embossing roll is applied to a fiber web having a basis weight of 9 to 50 g / m ² , a thickness of 0.1 to 0.25 mm, and a solution in which trehalose is blended. The method for producing a vegetable freshness-keeping sheet according to claim 1, wherein unevenness is formed on the surface. At least two fiber webs having a basis weight of 4.5 to 25 g / m ² are laminated, and a polyvinyl alcohol solution containing trehalose is applied as a binder to the lamination surface of the fiber web, and the basis weight is 9 to 50 g in the laminated state. method for producing freshness retaining sheets vegetables according to claim 7 or 8, characterized in that to create a support consisting / m ² of fibrous webs.   The method for producing a vegetable freshness-keeping sheet according to claim 9, wherein the binder is a solution containing 30 to 50 parts by mass of trehalose per 100 parts by mass of polyvinyl alcohol.

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