JPH04218346A - Production of jelly containing fruit - Google Patents

Abstract

PURPOSE:To produce the fruit-containing jelly holding the flavor of a raw fruit and having improved preservability for a long period by sealing and packaging a mixture of the raw fruit, a syrup liquid and a gelling agent in a flexible container and subsequently subjected to a pressurizing treatment under a specific condition. CONSTITUTION:A seed-free raw fruit cut into sizes of 1-3cm, a syrup liquid having a Brix suger degree of 15-30, and a gelling agent are mixed with each other, cooled to <=40 deg.C, and subsequently mixed with an acid to produce a mixture controlled to a pH of <=4.5. The mixture is degassed under vacuum of <=-750mmHg for 1-60min and subsequently sealed and packaged in a flexible container. The package is received in a piston-like liquid-tight pressure tank receiving a hydraulic medium, and subsequently subjected to a pressurizing treatment under a hydrostatic pressure condition of >=3000kg/cm<2> at <=40 deg.C.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for producing fruit-containing jelly, and more specifically, to a fruit-containing jelly that retains the texture, taste, aroma, and other flavors of raw fruit. Relating to a manufacturing method.

<Conventional technology> Conventionally, fruit jelly is a uniform mixture of fruit, syrup, and a gelling agent such as agar or gelatin, which is sealed in a plastic container and chilled at a temperature of 10°C or less. It is being distributed. In the production of this jelly, heat sterilization has conventionally been performed to kill microorganisms such as mold, yeast, and bacteria that have adhered to the raw materials or been mixed in during the production process. However, when the heat sterilization described above is applied,
Various problems have arisen. That is, the heat decomposes the aroma components of the fruit, impairing the fruit's original aroma and producing a heated odor, and particularly in citrus fruits, a so-called sweet potato odor is produced. Heat also affects the pigments in the fruit, causing discoloration and fading. In particular, green fruits like kiwi fruit fade and turn brown when heated. The texture also changes, and the fruit becomes softer, making an apple, for example, have a texture similar to a baked apple. When heating is performed in this way, the original flavor of the fruit is lost, resulting in a product with extremely poor texture.

<Problems to be Solved by the Invention> Techniques for sterilization or bacteriostasis without heat sterilization include methods such as the use of preservatives and bactericides, radiation sterilization, ultraviolet sterilization, and filtration sterilization. The use of preservatives and disinfectants is not preferred because their effectiveness is limited and they may have an effect on the human body. The safety of radiation sterilization is not recognized and its use is prohibited by law. Furthermore, since ultraviolet sterilization is a superficial sterilization, it cannot sterilize the inside of the fruit. Furthermore, filtration and sterilization can be applied to syrups, etc., but cannot be applied to fruits. As described above, none of the above-mentioned methods yields satisfactory results.

Therefore, the present invention provides a method for producing fruit-containing jelly that retains the flavor of fresh fruit, can be sufficiently sterilized, and can withstand long-term storage.

<Means for Solving the Problems> In other words, the present invention involves packaging a mixture of raw fruit, syrup, and gelling agent, the pH of which has been adjusted to 4.5 or less, in a flexible container to form a package. , a method for producing fruit-containing jelly, characterized in that the package is pressure-treated under conditions of a temperature of 40° C. or lower and a hydrostatic pressure of 3000 kg/cm 2 or higher.

In a preferred embodiment of the present invention, the above method further includes:
This process includes the step of permeating a syrup liquid whose pH has been adjusted to 4.5 or less into the fruit while degassing it under reduced pressure.

<Function> According to the production method of the present invention described above, fungi such as molds and yeasts are sterilized by pressurization. Bacteria cannot be sterilized even by pressure, but by adjusting the pH of the syrup to 4.5 or less, germination of bacterial spores is prevented, and as a result, the jelly can be preserved. It becomes possible. This pressure treatment
A sufficient bactericidal effect can be obtained at temperatures below ℃, and the flavor of the fruit mentioned above is not impaired and the fresh flavor is maintained.

In addition, in the present invention, when the syrup liquid is permeated into the fruit, this operation is performed under reduced pressure to remove air bubbles contained in the fruit, thereby preventing oxidative deterioration of the fruit due to the oxygen contained therein. Problems such as discoloration and fading due to the action of enzymes are prevented.

<Example> Next, examples of the present invention will be described.

The fruits targeted in the present invention can be the same as those contained in conventional jelly.

Specifically, citrus fruits such as mandarin oranges, apples, pears, pears, peaches, grapes, cherries, kiwi fruits, apricots, plums, melons, strawberries, blueberries, pineapples, etc. especially,
Fruits that contain a large amount of gas inside, such as apples, pears, pears, peaches, and strawberries, can provide extremely significant effects in one embodiment of the present invention.

As the sugars used in the syrup liquid, common sugars such as sugar, fructose, and glucose can be used. The sugar content of typical syrup liquids used for jelly is 15 to 30 on a Brix sugar meter.

The gelling agent may be a common gelling agent such as agar, gelatin, or carrageenan.

In the present invention, the above fruit, syrup liquid, and gelling agent are mixed. That is, the gelling agent and syrup liquid, which are preferably dissolved in warm water in advance, are heated to a temperature at which the gelling agent dissolves as necessary, completely dissolved and mixed uniformly, and then the fruit is added (hereinafter referred to as jelly). mixture). At this time, if the temperature of the syrup solution in which the gelling agent is dissolved is high, the flavor of the fruit will be impaired and the purpose of the present invention cannot be achieved. (Agar and carrageenan should be cooled to a temperature of around 50°C, gelatin should be around 30°C.) Then, after adding the fruit and mixing properly, cool the temperature to below 40°C, preferably around 25°C. It is desirable to cool it to room temperature.

The pH of the above mixture is adjusted by adding an appropriate acid so that the pH becomes 4.5 or less. acetic acid, citric acid, lactic acid,
Organic acids such as L-ascorbic acid, erythorbic acid, malic acid, succinic acid, tartaric acid, adipic acid, gluconic acid, fumaric acid, cinnamic acid, nicotinic acid, or hydrochloric acid, sulfuric acid,
Acids that are safe for food hygiene, such as phosphoric acid, can be used, and citric acid is preferred from the standpoint of taste and cost. According to research by the present inventors, germination of spores of bacteria such as Clostridium botulinum (heat-resistant bacteria) that cause food poisoning is suppressed to an extremely high level at pH 4.5 or lower. Therefore, by adjusting the pH in this way, even after sterilization, the growth of microorganisms that are slightly present can be suppressed, or depending on the type of bacteria, sterilization can be performed, thereby significantly increasing the shelf life of the jelly. This pH adjustment may be carried out, for example, by adding the acid to the syrup liquid in advance or by mixing it when dissolving the gelling agent.

The fruit should be thoroughly washed, preferably with the skin and seeds removed, and cut into pieces of, for example, 1 to 3 cm.

Also, usually, the fruits are soaked in syrup in advance to allow the syrup to penetrate. Here, in order to promote penetration of the syrup liquid and remove air bubbles contained in the fruit, it is preferable to carry out this step under reduced pressure for the following reasons. That is, if the pressure treatment described below is applied to the fruit while it contains air, the air bubbles will be released into the jelly after the treatment, and the appearance will be significantly deteriorated. In addition, the air contains oxygen, and due to the influence of this oxygen, fruits etc. deteriorate due to oxidation.
Flavor is lost. In addition, the fruit turns brown or fades due to the action of oxygen and enzymes contained in the fruit. In particular, the tissue of fruits is slightly destroyed by pressure treatment, and the enzymes responsible for this are not deactivated by pressure treatment (
According to conventional heat sterilization, the enzyme is inactivated by the heat), so this problem of discoloration and fading is serious. Therefore, it is extremely effective to degas by reducing the pressure when soaking in syrup. In addition, it is preferable to adjust the pH of the syrup liquid in advance as described above, as this allows bacteria present on the surface and inside of the fruit to become bacteriostatic.

The reduced pressure for degassing is preferably set to a degree of vacuum of -750 mmHg or less. If the degree of vacuum is insufficient, sufficient deaeration cannot be achieved, and the desired prevention of oxidative deterioration and discoloration and fading cannot be achieved. The time required for degassing varies depending on the type and size of the fruit, but is approximately 1 to 60 minutes at minus 750 mmHg.

In addition, it is preferable to use L-ascorbic acid, which has an antioxidant effect, as the acid used for the pH adjustment, in order to prevent the influence of oxygen. This L-ascorbic acid and the like may be used alone or in combination with other acids such as citric acid.

The jelly mixture obtained as described above is filled into a water-impermeable, flexible packaging container. Although the shape of the container is not particularly limited, it is preferably cup-shaped or tray-shaped in consideration of workability and distribution suitability. Specifically, water-impermeable plastic sheets such as polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polyvinyl chloride, and polycarbonate are formed by sheet forming methods such as vacuum forming, pressure forming, vacuum pressure forming, and plug-assisted vacuum forming. A container shaped like a cup or a tray is suitable. Furthermore, if necessary, a barrier thin film layer such as a gas barrier plastic film such as polyvinylidene chloride or ethylene-vinyl alcohol copolymer, metal foil, a metal vapor deposited layer, or a silicon oxide vapor deposit layer is laminated on the packaging container. be able to. However, considering the distribution form of the product, it is desirable that the container be transparent so that the contents can be seen through. Specific containers include polypropylene (200 μm)/ethylene-vinyl alcohol copolymer (200 μm)/polypropylene (3
An example is a laminated sheet having a thickness of 50 μm) formed into a cup shape with a diameter of 50 mm and a height of 30 mm by plug-assisted vacuum forming.

The container needs to be flexible.

That is, the pressure treatment in the present invention involves placing a container filled with a jelly mixture in a piston-shaped liquid-tight pressurized tank and adding a liquid (specifically, toluene, heptane, xylene, acetone, etc.) as a pressure transmission medium. However, since it is for food use, it is preferable to use water), compress the pressurized tank, and uniformly pressurize the container via a pressure transmission medium, that is, by hydrostatic pressure. Therefore, the container needs to be flexible so that the applied pressure is transmitted to the jelly mixture.

Additionally, the container must be completely liquid-tightly sealed. Therefore, in the case of a cup-shaped container, it is preferable to form a layer with good thermal adhesion on the inner surface of the container, and seal the opening by bonding the lid material by thermal adhesion. Note that when joining the lid material, it is preferable to reduce the amount of air in the head space as much as possible. That is, if there is oxygen in the headspace, this oxygen will contribute to detracting from the flavor of the jelly as described above, so using air (oxygen) removal means, such as degassing packaging or gas flash packaging, is This is a preferred embodiment.

In the present invention, the package of the jelly mixture filled and packaged as described above is heated at 40°C or lower and at a temperature of 3000 kg/cm.
Pressure treatment is carried out under conditions of two or more hydrostatic pressures. That is,
It was found that a good sterilizing effect could be obtained under such conditions, and the present invention was completed.

The effectiveness of pressure sterilization is determined by pressure and temperature factors for each type of microorganism. Processing time has little effect. Basically, fungi such as mold and yeast can be sterilized depending on pressure. On the other hand, bacteria cannot be completely sterilized even by pressure, and its effectiveness varies. Therefore, it is necessary to adjust the pH in order to suppress the growth of the few remaining bacteria.

There is no particular upper limit to the pressure, but the water contained in the jelly mixture is extremely high (for example, 10,000 kg).
It is known that when pressure (more than /cm2) is applied, a phase change occurs even at room temperature, resulting in solidification (freezing), and in this case, the tissue of the fruit is significantly destroyed, and the gel is destroyed, making it difficult to form a good jelly. This is not desirable because it does not occur. As can be seen from the experimental results described below, the sterilization effect is as follows:
/cm2 or more, about 4 to 5000 kg/cm2, is sufficient, and applying pressure higher than this has little merit.

In addition, a state generally called spoilage refers to a case where the number of bacteria is 10 6 /g or more, and if there are 10 5 or more bacteria / g, there is a strange smell and the food is not edible.

The number of strokes that can be well fed is less than 105 pieces/g, more preferably 103 pieces/g or less.

◎Experiment: Observation of bactericidal effect and flavor Apples from which the skin and core had been removed were cut into 10-15 mm squares. As the syrup liquid, a syrup liquid in which sugar was dissolved (Brix sugar content 18) was used, and citric acid and L-ascorbic acid were added to adjust the pH in various ways.

The apples were soaked in this syrup and degassed for 10 minutes at a vacuum level of minus 750 mmHg to remove air bubbles in the fruit and allow the syrup to penetrate. Furthermore, the syrup-soaked apples were soaked at 5° C. for 3 days to allow the syrup solution to penetrate sufficiently. Next, take this syrup liquid, heat it, add gelatin that has been swollen with water in advance,
Stir well to dissolve and mix, and make sure the gelatin does not gel.30
After cooling to ℃, it was filled into the aforementioned plastic cup-shaped container along with apples soaked in syrup, and immediately kept at room temperature (
The mixture was cooled to 25°C. Here, S, a type of yeast,
After inoculating accharomyces cerevisiae, the opening of the container was sealed with a lid. This package was subjected to pressure treatment by changing the pressure and temperature. Note that the treatment time was uniformly 30 minutes.

The number of viable bacteria in this package before and after the pressure treatment was measured based on the "Food Hygiene Inspection Guidelines."

Furthermore, these packages after the pressure treatment were subjected to 2
After being stored at a temperature of 5° C. for 2 weeks, the number of viable bacteria inside the package was measured, and the appearance and texture of the jelly were observed. The results are shown in Tables 1 and 2.

In addition, apple jelly packages obtained in the same manner as described above, except that sufficient deaeration was not performed during soaking in syrup, were treated and stored in the same manner, and changes in appearance were observed.

The results are shown in Table 3.

In addition, using peaches cut into 10-15 mm cubes from which the skin and seeds have been removed, and a syrup solution with a Brix sugar content of 23, the pH of which was adjusted in various ways by adding citric acid and L-ascorbic acid, the same method as above was used. We conducted an experiment. The results are shown in Table 4.

From the above results, it can be seen that when the pressure is 3000 kg/cm2 or more and the pH is 4.5 or less, a sufficient bactericidal effect can be obtained. On the other hand, when the pH was set to 5, fungi could be sterilized by setting the pH to 3000 kg/cm2 or higher, but fruit-derived bacteria multiplied during storage.
It was found that it was not suitable for food. It is also clear that the flavor will be impaired if the temperature is not lower than 40°C. Furthermore, it can be seen that when deaeration is performed, an extremely good fruit-containing jelly can be produced without browning.

<Effects of the Invention> As described above, the method of the present invention, unlike the conventional method of heat sterilization, retains the flavor of fresh fruit and can be stored for a long period of time. Now we can offer fruit jelly.

patent applicant Toppan Printing Co., Ltd. Representative: Kazuo Suzuki

Claims (2)

[Claims] Claim 1: A mixture consisting of fresh fruit, syrup liquid, and gelling agent, the pH of which has been adjusted to 4.5 or lower, is sealed and packaged in a flexible container, and the package is stored at 40°C. Below, 300
A method for producing fruit-containing jelly, which comprises pressurizing the jelly under conditions of hydrostatic pressure of 0 kg/cm2 or more. 2. The method according to claim 1, comprising the step of permeating the raw fruit with a syrup solution whose pH has been adjusted to 4.5 or less while degassing under reduced pressure.