JPH08154643A - Pack for keeping temperature of foodstuff - Google Patents

Abstract

PURPOSE: To obtain the subject pack effective in both of cold insulation and heat insulation and keeping the temperature of a foodstuff carried from a place of production by packing an aqueous solution having property causing gelation by heating and obtained by dissolving cellulose ether powder to which tannic acid is attached under alkaline conditions into a bag of plastic film. CONSTITUTION: An aqueous solution having property causing gelation by heating and obtained by attaching about 1-40 pts.wt. tannic acid to 100 pts.wt. cellulose ether powder and dissolving the cellulose ether under alkaline conditions is packed into a bag of a plastic film. The solution is hardly made to flow from the bag and the solution itself is free from problem on hygienical aspect and the temperature of warm foods, frozen food, etc., during transportation can be retained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pack agent for maintaining the temperature of food products transported from the place of origin.

[0002]

2. Description of the Related Art Fresh foods such as fish and shellfish and meat are packed in a heat-retaining container such as expanded polystyrene together with a cold-packing agent and transported from the place of origin. The cold-packing agent is a frozen polyethylene bag filled with an aqueous solution of high viscosity. A water-soluble polymer such as polyvinyl alcohol, a cellulose derivative, sodium acrylate, or polyethylene oxide is dissolved in the aqueous solution in the bag to increase the viscosity. This cold-packing agent prevents the temperature inside the container during transportation from rising, and the fresh food is transported without spoilage.

In the case of a cold-packing agent filled with water containing no water-soluble polymer, water with a low viscosity inside the bag is likely to flow out, so be careful when handling the water-filled bag before freezing. Requires. Therefore, for transporting fresh foods, cold packs in which a bag is filled with a highly viscous aqueous solution of a water-soluble polymer are widely used.

[0004] In order to prevent warm food such as a lunch box from being cooled, it is packed in a heat-retaining container together with a heat-retaining pack agent and transported. As the heat-retaining pack agent, a used body-like heating element containing iron oxide powder, a water retaining agent, water, salt and activated carbon as main components was used. The heat retaining pack agent generates heat only once, and does not generate heat again after the heat generation ends.
For this reason, the fever may end during the transportation and the bento may be cooled.

[0005]

As a means for transporting bento without cooling, there is a method of heating a cold-packing agent used for transporting fresh food to use it as a warming-packing agent for bento. . However, since the viscosity of the liquid filled in the bag is lowered by heating, the bag should be handled with extreme caution.

As a heat retaining pack having a high solution viscosity,
Some of them utilize the crosslinking reaction of cellulose ether.
The manufacturing method is specifically described below. First,
The surface of the water-soluble cellulose ether powder is crosslinked with glyoxal to prepare an insoluble powder. After the powder is dispersed in water, an alkaline substance such as sodium carbonate is added to remove the cross-linking between glyoxal and the cellulose ether to dissolve the cellulose ether. This solution is filled in a bag made of polyethylene or the like and used as a heat insulating pack agent.

However, Glyoxal is the number 341 announced by the Director of Labor Standards Bureau, Ministry of Labor, dated June 6, 1994.
No. 2 “Handling of Chemical Substances with Mutagenicity”
It has been designated as a chemical substance that has been identified as a mutagen.
Therefore, it is hygienically unfavorable to carry the cold-packing agent in which a bag is filled with a cellulose ether solution having a viscosity increased by crosslinking with glyoxal in the same container as the food.

The present invention has been made to solve the above-mentioned problems, and a solution having a hygienic safe composition is filled in a bag, the solution does not easily flow from the bag, and a heat-retaining pack is also used as a cold-packing agent. It is an object of the present invention to provide a temperature maintaining pack agent for food products that can be used as an agent.

[0009]

Means for Solving the Problems A temperature-maintaining pack for foodstuffs according to the present invention, which has been made to achieve the above object, comprises:
A heat-gelling aqueous solution obtained by dissolving cellulose ether powder having tannic acid adhered thereto under alkaline conditions is filled in a plastic film bag.

It is preferable that 1 to 40 parts by weight of tannic acid is attached to 100 parts by weight of the cellulose ether powder. If the adhered amount is less than 1% by weight, the cellulose ether powder will not disperse in water and will aggregate. When it exceeds 40 parts by weight, the cellulose ether powder dispersed in water becomes difficult to dissolve under alkaline conditions.

Examples of the cellulose ether powder include methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose and hydroxyethyl ethyl cellulose. These powders may be used alone or as a mixture. Methylcellulose is approved not only as a drug but also as a food additive to be added up to 2% by weight in food. Hydroxypropyl methylcellulose, hydroxyethyl methylcellulose,
There is no report on mutagenicity of hydroxyethylethylcellulose.

The cellulose ether powder preferably has a viscosity of a 2 wt% aqueous solution at 20 ° C. of 50 cp or more. 50 cp
When it is less than the above range, it is not possible to impart the necessary viscosity to the aqueous solution with a small amount.

Tannic acid is approved as a food additive or a pharmaceutical additive. To attach the tannic acid to the cellulose ether, the tannic acid solution may be sprayed on the cellulose ether powder. The tannic acid solution may be an aqueous solution, an ether solution, or an alcohol solution such as ethanol, but the tannic acid solution has no risk of ignition in the drying step.

The concentration of the tannic acid solution is preferably 5 to 20% by weight. If the concentration is less than 5% by weight, a large amount of tannic acid solution must be sprayed to prevent agglomeration of the cellulose powder. If it exceeds 20% by weight, the effect obtained by dissolving a large amount of tannic acid in a solvent is not exhibited.

The average particle size of the cellulose powder to which tannic acid is attached is preferably 30 to 350 μm. Particle size is 30
If it is less than μm, the particles tend to adhere to each other when spraying the tannic acid solution to form large aggregates. Particle size is 35
If it exceeds 0 μm, the dissolution of the powder will be delayed.

The concentration of cellulose ether in the heat gelling aqueous solution is preferably 1 to 10% by weight. When the amount is less than 1% by weight, the bag is difficult to handle because the viscosity of the solution is low. 1
When it exceeds 0% by weight, the bag is easy to handle, but it is not economically preferable.

The method for producing the temperature-maintaining pack for foodstuffs is specifically as follows. First, an aqueous tannic acid solution is sprayed onto the cellulose ether powder while stirring the cellulose ether powder with a high-speed stirring device such as a Henschel type mixer. After the spraying is finished, the powder is dried and then placed in a plastic bag having a required strength such as polyethylene or vinyl chloride, and water is added to disperse the powder. As a drying method, a usual drum dryer or paddle dryer may be used.

Then, sodium carbonate or sodium hydrogen carbonate is added to adjust the pH of the aqueous solution to 8 or more, and the cellulose ether is dissolved in water. Sodium carbonate and sodium hydrogencarbonate are approved as food additives and pharmaceutical additives, like tannic acid.

The obtained heated gelled aqueous solution is filled in a plastic film bag to complete the production of a temperature-maintaining pack for food products. Similarly, an aqueous cellulose ether solution may be prepared in advance in a tank or the like and then filled in a plastic film bag.

The temperature-maintaining pack for food products produced by the above method is put in a container made of a heat insulating material together with cooled fresh food when the fresh food is transported. When this pack agent is heated, the aqueous solution inside the bag gels. Even if the plastic bag is broken, the aqueous solution will not seep outside. It takes time for the gel to melt, so
The temperature of warm foods such as bento can also be maintained for a long time. Moreover, since this gel returns to a highly viscous aqueous solution when cooled, it can be used repeatedly.

[0021]

EFFECTS OF THE INVENTION The temperature-maintaining pack for food products of the present invention can be used both for carrying warm food such as bento and for carrying frozen products such as fresh food. The aqueous solution with which the bag is filled gels when heated, so it does not flow out of the bag and has a hygienic and safe composition.
Therefore, food items can be transported in a hygienic manner.

[0022]

EXAMPLES Examples of the present invention will be described in detail below.

Example 1 Methylcellulose (SM-8000 manufactured by Shin-Etsu Chemical Co., Ltd.)
Add 100 parts by weight to a Henschel mixer for 500 r
20% by weight tannic acid aqueous solution with stirring at 5 pm
1 part by weight of tannic acid was attached to 100 parts by weight of methyl cellulose by spraying. The obtained cellulose ether powder was dried by a dryer at 100 ° C. for 8 hours, put in a polyethylene bag, and 100 cc of water was added.
Further, 2 parts by weight of sodium carbonate was added, and the mixture was allowed to stand for 8 hours to dissolve the powder to prepare an aqueous solution, and this solution was filled in a polyethylene bag to prepare a pack. The concentration of cellulose ether in the solution inside the bag was 2% by weight.

The dissolved state of the powder of the obtained pack agent, the frozen product thawing time, and the temperature decreasing time were investigated.

Regarding the dissolved state of the powder, the one in which the powder in the solution was agglomerated or not completely dissolved was regarded as poor, and the one in which the powder was completely dissolved was regarded as good.

The frozen product thawing time is the time until the ice is completely melted by freezing the pack in a freezer at -5 ° C and then leaving it at room temperature at 20 ° C.

The temperature falling time means 2 minutes after the pack agent is immersed in hot water at 100 ° C. for 30 minutes to gel the solution inside.
It is the time until the pack agent returns to 20 ° C. after being left at room temperature of 0 ° C. The results of these investigations are shown in Table 1.

Example 2 In the same manner as in Example 1, 100 parts by weight of hydroxypropylmethyl cellulose (60SH-50 manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed with 50 parts by weight of an aqueous tannic acid solution, and 10 parts by weight of tannic acid. Parts were attached. The powder obtained was dispersed in water, and 5 parts by weight of sodium hydrogencarbonate was added to the mixture.
A pack agent was produced in the same manner as in. The concentration of cellulose ether in the solution inside the bag was 10% by weight. The dissolution state of the powder of the pack agent, the frozen product thawing time, and the temperature decrease time were investigated, and the results are shown in Table 1.

Example 3 In the same manner as in Example 1, 100 parts by weight of hydroxyethylmethylcellulose (SEB-30000 manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed with 100 parts by weight of an aqueous tannic acid solution, and 20 parts by weight of tannic acid was added. Attached. The powder obtained was dispersed in water, and 5 parts by weight of sodium hydrogencarbonate was added to the mixture.
A pack agent was produced in the same manner as in. The cellulose ether concentration of the solution inside the bag was 5% by weight. The dissolution state of the powder of the pack agent, the frozen product thawing time, and the temperature decrease time were investigated, and the results are shown in Table 1.

Example 4 In the same manner as in Example 1, 200 parts by weight of an aqueous tannic acid solution was sprayed onto 100 parts by weight of hydroxyethylethyl cellulose (E481 FQ manufactured by Bellol Nobel Co.) to adhere 40 parts by weight of tannic acid. . The obtained powder was dispersed in water, 3 parts by weight of sodium carbonate was added, and a pack agent was produced in the same manner as in Example 1. The concentration of cellulose ether in the solution inside the bag was 1% by weight. The dissolution state of the powder of the pack agent, the frozen product thawing time, and the temperature decrease time were investigated, and the results are shown in Table 1.

Comparative Example 1 In the same manner as in Example 1, 100 parts by weight of methyl cellulose (SM-8000 manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed with 2 parts by weight of an aqueous tannic acid solution, and 0.4 parts by weight of tannic acid. Was attached. The obtained powder was dispersed in water, 2 parts by weight of sodium carbonate was added, and a pack agent was produced in the same manner as in Example 1. The concentration of cellulose ether in the solution inside the bag was 2% by weight. The dissolution state of the powder of the pack agent, the frozen product thawing time, and the temperature decrease time were investigated, and the results are shown in Table 1.

Comparative Example 2 Only water was put in a polyethylene bag and 100 cc of water was added to prepare a pack. The dissolution state of the powder of the pack agent,
The frozen product thaw time and the temperature decrease time were investigated, and the results are shown in Table 1.

[0033]

[Table 1]

As shown in Table 1, the packs of Comparative Examples 1 and 2 have a smaller amount of tannic acid attached than Examples 1 to 4. For this reason, it becomes a pack agent with inferior performance.

Claims (4)

[Claims] 1. A temperature-maintaining pack for food products, characterized in that a bag of plastic film is filled with a heat-gelling aqueous solution in which a cellulose ether powder to which tannic acid is adhered is dissolved under alkaline conditions. 2. The temperature-maintaining pack for food products according to claim 1, wherein 1 to 40 parts by weight of the tannic acid is attached to 100 parts by weight of the cellulose ether powder. 3. The temperature maintenance of the food product according to claim 1, wherein the cellulose ether powder is at least one kind selected from methylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose and hydroxyethylethylcellulose. Pack agent. 4. The temperature-maintaining pack for food products according to claim 1, wherein the concentration of cellulose ether in the heat-gelling aqueous solution is 1 to 10% by weight.