JP3411881B2 - Process for producing pruned products and resulting pruned products - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing a pruned product used for canning, cakes and the like, as well as for direct eating, and a pruned product obtained thereby.

[0002]

2. Description of the Related Art Conventionally, fresh plums have been dried with hot air to reduce the water content, and have been dried with prune (NC prune,
It is stored and managed as dry plums. A processed pruned product for direct eating is manufactured using this prune, for example, as follows. That is, first, the prune is washed with running water, and water is replenished by heating water with steam or the like. The seeds are then deseeded to obtain seedless prune. Then, in order to prevent the growth of general bacteria, mold, yeast, etc., a preservative such as potassium sorbate is added and then packaged to obtain a pruned product for direct eating.

According to such a method, since the growth of microorganisms is effectively prevented, there is no problem even when it is put on the market as a product, but in recent years, foods containing a preservative have been shunned by consumers. Therefore, provision of pruned products that do not use preservatives is desired.

Therefore, in the above method, there has been proposed a method in which the amount of water supply is reduced to suppress the growth of microorganisms and a preservative is not added.

According to this method, since no preservative is added, the method has the advantage of being easily accepted by consumers, but on the other hand, since the obtained pruned product has a low water content, it is too hard and its commercial value is low.

In view of the above, a method has been proposed and put to practical use in which seedless prunes are packaged in an airtight container and then the container is pressurized and heat sterilized by using a retort sterilizer.

[0007]

However, the pruned products obtained as described above have the drawbacks of being extremely soft and sticky. In addition, since heat sterilization must be performed under conditions of high heat and long time (for example, 100 to 120 ° C. for 10 to 60 minutes), there is a disadvantage that the flavor of the prune itself is lost and a caramel flavor is generated.

The present invention has been made in view of such circumstances, and a method for producing a pruned product which can effectively prevent the generation of microorganisms without using a preservative and has a good flavor and texture. And the purpose is to provide a pruned product obtained thereby.

[0009]

In order to achieve the above object, the present invention is a method for producing a pruned product obtained by subjecting a prune to heat sterilization, wherein the heat sterilization absorbs water. The first gist is a process for producing a pruned product, which is carried out by directly heating and hydrolyzing the above with steam, and then hermetically packaging it prior to cooling and holding it in that state.

A second aspect of the present invention is a pruned product obtained by the method for producing a pruned product described above and having a water activity in the range of 0.75 to 0.90.

The present inventors have conducted extensive studies to obtain a pruned product which can effectively prevent the generation of microorganisms without using a preservative and has a good flavor and texture. In the process, the present inventors, retort sterilization conventionally used, is a method of packaging and heating the prune in an airtight container, in order to obtain the desired sterilization effect, at high temperature For a long time (for example, 10 to 60 at a temperature of 100 to 120 ° C.)
Therefore, the heat near the container causes a problem such as caramel odor due to high heat, and the air in the center of the container does not easily transfer heat, resulting in high quality pruning. We paid attention to the fact that no product was obtained. Therefore, the present inventors have conducted a study on a method capable of performing good heat sterilization and obtaining a high quality pruned product, instead of a method such as retort sterilization. In the process of studying it, we focused on the hot-fill packaging technology (hot pack technology) used for sterilizing beverages, and recalled applying this technology to sterilization treatment of prunes. However, since the beverage is a liquid substance and the prunes are relatively large solid substances (about ³ to 15 cm ^{3 in} size), there is a big difference in heat conductivity between the two, so the technology related to liquid substances should be considered. It was recalled that a good bactericidal effect could not be obtained even if it was directly applied to the prune. Therefore, as a result of repeated experimental research to make it possible to apply the hot pack technology, the prune to be sterilized was made to absorb water, and the absorbed prune was heated and hydrolyzed by steam, and then packed and stipulated. The present invention was accomplished by finding out that the prune can be sterilized favorably for a long period of time, and that the obtained pruned product has good flavor and texture.

[0012] In particular, as the method for heating and hydrolyzing with steam, a method in which water-absorbed prunes are passed under a steam atmosphere is adopted, or the above holding is carried out at a core temperature of 60 to 90 ° C for 1 to 15 minutes. If it is carried out under the condition of the above range, heat conduction will be particularly smooth and uniform, and the balance between the sterilizing effect and the flavor will be particularly good.

If the water activity of the pruned product obtained as described above is set in the range of 0.75 to 0.90, a good bactericidal effect can be maintained for a longer period of time.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described.

The process for producing a pruned product of the present invention is a process for producing a pruned product obtained by subjecting a prune to heat sterilization, wherein the heat sterilization directly heats and hydrates the absorbed prunes with steam. After that, it is carried out by hermetically packaging and then maintaining the state as it is before cooling.

The raw material used in the present invention is prune (N
C prune, dried plum). This prune is usually made from fresh plums (water content 80
~ 90% by weight) is dried with hot air to a water content of 16-2.
It has been reduced to 0% by weight and can be stored for a long period of about 2 years.

In the present invention, the water-absorbed prunes to be heat-sterilized (hereinafter referred to as "water-absorption prunes") are
For example, it can be obtained by washing the above prune with running water and then performing steam heating and hydrolyzing treatment, hot water treatment and the like.

The steam heating and adding method may be carried out, for example, by passing the prune washed with running water under a steam atmosphere (about 90 to 100 ° C.), or spraying hot water on the washed prune with running water ( 90 ~
A method of spraying about 100 ° C.) may be used. Examples of the hot water treatment method include a method in which the prune washed with running water is immersed in a hot water bath (about 90 to 100 ° C.) for several minutes.

The water content of the absorbent prunes is 26-3.
It is preferably set in the range of about 0% by weight.
Within this range, the heating and hydrolyzing treatment with steam is performed smoothly and uniformly, and a good sterilizing effect can be obtained. Incidentally, the water content, after crushing and mixing a predetermined amount of water-absorbing prunes, extract a predetermined amount from the resulting mixture, the extract, the average of the values measured multiple times using a water content measuring instrument Say.

Further, in the present invention, as the method for heating and hydrolyzing the water-absorbing prunes with steam, for example, a method of passing the water-absorbing prunes under a steam atmosphere, spraying hot water into the water-absorbing prunes is performed. There are methods. Above all, the prune extract does not elute and the flavor is not deteriorated, and even if water is added, the surface of the pruned product will have a smooth texture,
A method in which a water-absorbing prun is passed through under a steam atmosphere is preferred. The temperature of the steam is 70-
It is preferably set in the range of 100 ° C.

The method of carrying out the above water absorption prunes in a steam atmosphere can be carried out, for example, by using the square tunnel steamer shown in FIG. In the figure, reference numeral 1 denotes a tunnel, inside which a conveyor 2 is arranged, so that the water absorption prunes 3 can be sent from left to right. A plurality of steam inlets 4 are provided at predetermined intervals on the bottom of the tunnel 1 so that steam can be introduced into the tunnel 1 from the bottom to the top.

Using the above rectangular tunnel steamer, first, steam is introduced into the tunnel 1 to adjust the temperature in the tunnel 1 to about 70 to 100 ° C., and the water absorption prunes 3 placed on the conveyor 2 are left. To move to the right. At this time, the introduced steam moves from the bottom to the top in the tunnel 1, and each of the water absorption prunes 3 comes into direct contact with the steam. In this way
Steam can be brought into direct contact with the water absorption prunes 3.

The rectangular tunnel steamer shown in FIG. 2 can also be used. In the figure, 1 is a tunnel,
A conveyor 2 is provided inside the water absorbent so that the water absorption prunes 3 can be sent from left to right. A pipe 5 having steam ejection holes (not shown) is arranged in a meandering manner at the bottom of the tunnel 1 so that steam can be introduced into the tunnel 1 from the bottom to the top. It is like this. In addition, 6 is a fan for circulating steam and increasing the frequency of contact with the water absorption prunes 3.

Further, the rectangular tunnel steamer shown in FIG. 3 can be used. In the figure, reference numeral 1 denotes a tunnel, inside which a conveyor 2 is arranged, so that the water absorption prunes 3 can be sent from left to right. The bottom of the tunnel 1 is filled with water 7. The water 7 is boiled by a heat medium (steam, etc.) so that the steam can be introduced into the tunnel 1 from the bottom to the top. ing. In addition, 6 is a fan for circulating steam and increasing the frequency of contact with the water absorption prunes 3.

In the present invention, it is preferable that the condition of keeping the product in the packaged state is set such that the core temperature is 60 to 90 ° C. and the holding time is 1 to 15 minutes. That is, if the core product temperature is too high or the holding time is too long,
If the temperature of the core product is too low or the holding time is too short, the bactericidal effect will not be sufficient and microorganisms (especially mold and yeast) will grow during storage. This is because there is a risk. The core temperature is
It refers to the average of the values measured by inserting the temperature measuring part of the thermometer into the center of each prune for a plurality of arbitrarily selected prunes.

An example of the method for producing the pruned product of the present invention will be described with reference to the flow chart shown in FIG. That is, first, the prune is washed with running water, and then steam heating and hydrolyzing treatment is performed. As a result, bacteria and the like adhering to the outer surface of the prune are removed and sterilized, and water is supplied to soften the pulp. Then, the seeds are removed to obtain seedless water-absorbing prunes. Next, the seedless water-absorbing prunes obtained are passed through a steam atmosphere to be heated and hydrolyzed, and then immediately loaded into a packaging bag and sealed (wrapped), and kept in that state for a predetermined time (heat retention). ) Do. As a result, the microorganisms that have not been sterilized by the steam heating and hydrolyzing treatment and the microorganisms that are secondarily contaminated during seed removal can be sterilized, and can be sterilized to the extent that they can be put on the market. Then, the pruned product of the present invention is obtained by cooling.

In the pruned product thus obtained, the heat applied by the heating and hydrolyzing treatment with steam is directly and efficiently transmitted to the water-absorbing prunes.
Since it is produced by smoothly conducting water in the water-absorbing prunes, microorganisms such as yeast and mold can be sterilized in good condition. Further, since the heat is conducted substantially uniformly by the smooth conduction of heat, the quality of the prune is not significantly impaired, and the flavor and texture are improved. Since the sterilization is performed well by the heating and hydrolyzing treatment, it is not necessary to add a preservative, and the product is easily accepted by consumers.

The water content of the pruned product obtained as described above is preferably set in the range of 30 to 42% by weight. Within such a range, the pruned product will be reasonably soft, will not be sticky, and will have a smooth texture. The water content is the average of the values obtained by crushing and mixing a predetermined amount of pruned product, extracting a predetermined amount from the obtained mixture, and measuring the extract a plurality of times using a water content measuring instrument. Say.

The water activity of the pruned product is
It is preferably set in the range of 0.75 to 0.90, and particularly preferably in the range of 0.76 to 0.88. That is, when the water activity is less than 0.75, the texture of the pruned product becomes poor, and when the water activity exceeds 0.90, the growth of microorganisms (particularly thermostable bacteria) is effectively prevented. It is not possible to do so, and the processed and pruned products may be deteriorated or deteriorated, which makes it difficult to store them for a long time. The water activity is obtained by crushing and mixing a predetermined amount of pruned product, extracting a predetermined amount from the resulting mixture, and averaging the values of the extract measured a plurality of times using a water activity measuring device. Say.

As described above, the method for producing the pruned product of the present invention is not limited to the method in which the water absorption and the heating and hydration treatment of the prune are carried out separately. For example, the speed of the conveyor 2 of the above-mentioned rectangular tunnel steamer is changed. The water absorption and the heating and hydration treatment may be continuously performed by slowing the length or lengthening the tunnel 1. With this method, seeded pruned products can be obtained which effectively prevent the generation of microorganisms and have a good flavor and texture.

The processed pruned product of the present invention can be put on the market for direct food as it is, or can be used for canning, cakes and the like.

Next, examples will be described together with comparative examples.

[0033]

Example 1 First, a prune (water content 18% by weight) was prepared. This prun is made from 80 fresh plums (water content 85% by weight) collected in California.
It was dried by hot air under the condition of ~ 90 ° C for 15-18 hours and stored and managed. Next, the prune was washed with running water, and then steam heating and hydration treatment was performed using a square tunnel steamer (SM-STM-600, manufactured by Sun Plant Industry Co., Ltd., tunnel length 10 m) (temperature inside the tunnel: 98-100 ° C, tunnel transit time:
For 15 minutes). Then, the seeds were removed to obtain seedless water-absorbing prunes (water content 28% by weight). Next,
Using the same square tunnel steamer (tunnel length 5 m) as described above, the obtained seedless water-absorbed prunes were subjected to heat hydration treatment (temperature in tunnel: 98 to 100 ° C., tunnel passage time: 3 minutes). Immediately after the operation, it was loaded in a packaging bag, sealed, and kept in that state. The holding conditions were set so that the core temperature was 70 ° C. for 10 minutes.
Then, by cooling, a target pruned product (water content 32% by weight, water activity 0.79) was obtained.
The water content, water activity, and core product temperature were measured as follows.

[Water content] 500 g of water-absorbed prunes (processed prunes) were crushed and mixed, and 150 g from this mixture.
Was arbitrarily extracted. The water content measuring device [Dried Fruit Moisture Tester (DFM
Tester), Dried Fruit Association of California
(California Association of Fruits and Fruits)], and the average of them was expressed as water content.

[Water activity] Absorbed prunes (prune processed products) (500 g) were crushed and mixed, and 150 g was obtained from this mixture.
Was arbitrarily extracted. Then, this extract was measured 3 times using a water activity measuring device (AW METER WA-360, manufactured by Shibaura Electronics Co., Ltd.), and the average thereof was expressed as water activity.

[Core temperature] For each of the 10 water absorption prunes that are being held, the digital thermometer (MODEL)
(SK-1250MC, manufactured by Sato Keiki Seisakusho Co., Ltd.) was inserted and measured, and the average of them was shown as the central item temperature.

[0037]

[Example 2] Except that the time for passing through the tunnel during the heating and hydrolyzing treatment of seedless water-absorbing prunes was set to 2 minutes, and the condition for holding after heat sterilization was set to the core temperature of 60 ° C for 15 minutes. In the same manner as in Example 1, a pruned product (water content 31% by weight, water activity 0.78) was obtained.

[0038]

[Example 3] Except that the seed waterless prunes were heated for 4 minutes in the tunnel during the heating and hydrolyzing treatment, and the condition for holding after heat sterilization was set to a core temperature of 80 ° C for 5 minutes. In the same manner as in Example 1, a pruned product (water content 33% by weight, water activity 0.80) was obtained.

[0039]

[Example 4] Except that the time for passing through the tunnel during the heating and adding treatment of seedless water-absorbing prunes was 5 minutes, and the condition for holding after heat sterilization was that the core product temperature was 90 ° C for 1 minute A prune processed product (water content 34% by weight, water activity 0.81) was obtained in the same manner as in Example 1.

[0040]

[Example 5] A seedless water-absorbing prune having a water content of 26% by weight was used, and the tunnel passage time during the heating and hydrolyzing treatment of the seedless water-absorbing prune was set to 2 minutes, and the conditions for holding after heat sterilization were mainly set. A pruned product (water content 30% by weight, water activity 0.75) was obtained in the same manner as in Example 1 except that the product temperature was set to 60 ° C. for 15 minutes.

[0041]

[Example 6] A seedless water-absorbing prune having a water content of 30% by weight was used. A pruned product (water content 42% by weight, water activity 0.90) was obtained in the same manner as in Example 1 except that the product temperature was set to 90 ° C for 1 minute.

[0042]

Example 7 First, the same prune (water content 18% by weight) as in Example 1 was prepared, and this prune was washed with running water. Next, a square tunnel steamer (SM-STM-600 manufactured by Sun Plant Co., Ltd., tunnel length 1
0 m) was used to continuously perform water absorption and heat hydration treatment (temperature in tunnel: 98 to 100 ° C., tunnel passage time: 4 minutes). Then, it was immediately loaded into the packaging bag, sealed, and kept in that state. The holding conditions were set so that the core temperature was 70 ° C. for 10 minutes. Then, by cooling, a target pruned product (with seeds, water content 32% by weight, water activity 0.79) was obtained.

[0043]

Comparative Example 1 First, in the same manner as in Example 1, a seedless water-absorbing prune (water content 28% by weight) was obtained. Then, 40% potassium sorbate was added to the seedless water absorption prunes.
By adding 0 ppm (as sorbic acid) and loading in a packaging bag, a pruned product (water content 29% by weight, water activity 0.74) was obtained.

[0044]

Comparative Example 2 A seedless water-absorbing prune (moisture content 25% by weight) obtained in the same manner as in Example 1 was loaded into a packaging bag as it was to prepare a pruned product (moisture content 25% by weight, moisture content 25% by mass). An activity of 0.70) was obtained.

[0045]

Comparative Example 3 First, in the same manner as in Example 1, a seedless water-absorbing prune (water content 28% by weight) was obtained. Next, the seedless water-absorbing prunes and water are filled into a packaging container, and the packaging container is sterilized by heating under pressure using a retort sterilizer to obtain a pruned product (water content 40% by weight, water activity). 0.88) was obtained.

The pruned products of Examples and Comparative Examples thus obtained were evaluated according to the following criteria. The results are shown in Tables 1 and 2 below.

[Sensory Evaluation] The texture, flavor and touch of prunes were evaluated as follows. *: Tooth texture ○: Moderately soft. Δ: Slightly hard X: Too hard or too soft. *: Flavor ∘: There is no unpleasant odor and a good flavor is provided. X: Caramel flavor and unpleasant flavor. *: Feeling ○: Smooth. X: Sticky.

[Sterilization Evaluation] Each pruned product was left in a packaged state for 6 months, and the sterilization effect (bacteriostatic effect) was evaluated as follows. ◯: No microorganism-derived colony was found. X: Even one colony derived from a microorganism was seen.

[0049]

[Table 1]

[0050]

[Table 2] * 1: The growth of microorganisms was suppressed by the bacteriostatic effect of potassium sorbate. * 2: Since water absorption is suppressed, the water activity is low,
The growth of microorganisms was suppressed.

From the results shown in Tables 1 and 2, it can be seen that all of the pruned products of the examples are sufficiently sterilized and have good texture, flavor and touch and are good products. . On the other hand, the product of Comparative Example 1 can be said to be a good result as a whole, but it has a drawback of being slightly hard and has a low commercial value because a preservative is added. The product of Comparative Example 2 is
It can be seen that it is too hard due to the low water content. Since the product of Comparative Example 3 was subjected to the retort sterilization treatment, it was found that an unpleasant caramel odor was generated and the product had a sticky feeling. It also has the drawback of being too soft.

[0052]

INDUSTRIAL APPLICABILITY As described above, the process for producing the pruned product of the present invention is such that the water-absorbed prunes are directly heated and hydrolyzed by steam, then sealed and packaged prior to cooling, and kept in that state for heat sterilization. Is to do. Therefore, the heat applied by the heating and hydrolyzing treatment with steam efficiently raises the temperature of the surface of the water-absorbing prunes and smoothly conducts through the water-absorbing prunes, and as a result, sterilization is performed in a good state. In addition, since the heat is conducted substantially uniformly due to the smooth conduction of heat, the quality and quality of the prunes are not significantly impaired, and the flavor and texture of the obtained pruned products are excellent. Therefore, healthy foods rich in dietary fiber and minerals are delicious and delicious without being shunned by consumers.
It can be provided in an easy-to-eat form.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a rectangular tunnel steamer used for a heating and hydrolyzing treatment with steam.

FIG. 2 is a schematic diagram showing another example of a rectangular tunnel steamer used for a heating and hydrolyzing treatment with steam.

FIG. 3 is a schematic view showing still another example of the rectangular tunnel steamer used for the heating and hydrolyzing treatment with steam.

FIG. 4 is a flowchart showing an example of a method for producing a pruned product of the present invention.

Continuation of front page (56) Reference JP-A-3-232451 (JP, A) JP-A-58-99321 (JP, A) JP-A-61-28342 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) A23L 1/212-1/218 A23L 3/00-3/3598 A23B ⁷ /00-9/34

Claims (4)

(57) [Claims] 1. A method for producing a pruned product obtained by subjecting a prune to heat sterilization, wherein the heat sterilization comprises directly heating and hydrolyzing the absorbed prunes with steam, and then hermetically packaging prior to cooling. Then, the method for producing the pruned product is characterized in that it is carried out by maintaining the state. 2. The method for producing a pruned product according to claim 1, wherein the method of heating and hydrolyzing with steam is a method in which the absorbed prune is passed under a steam atmosphere. 3. The core temperature of the holding is 60 ° C. to 90 ° C.
The method for producing a pruned product according to claim 1 or 2, which is carried out under the conditions of 1 to 15 minutes. 4. A water activity of 0.75, obtained by the method for producing a pruned product according to claim 1.
A pruned product characterized by being set in the range of up to 0.90.