JPH0198440A - Preparation of dried persimmon - Google Patents

Abstract

PURPOSE:To stabilize the qualities of dried persimmons and contrive the omission of drying work and the shortening of drying periods, by receiving pared fresh persimmons in a drying chamber and supplying a flow of drying air into the chamber at a specific temperature and flow rate to perform initial removal of astringency and drying of the persimmons. CONSTITUTION:Pared fresh permissions are received in a drying chamber and a flow of drying air preferably in its upward flow is supplied into the chamber from a supply port at 22-30 deg.C, 40-85% relative humidity and 0.2-1.0m/sec average flow rate to apply initial removal of astringency and drying to the fresh persimmons. Drying work for the persimmons can be efficiently performed compared with sun-driving processes without being influenced by weather.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing dried persimmons that achieves stable quality, omits drying work, and shortens the drying period.

[Conventional technology]

Traditionally, in the production of dried persimmons, raw persimmons are generally peeled, tied together with string, hung from bamboo poles, placed in a well-ventilated place such as a glass greenhouse, and dried in the sun for about 20 days. After that, the process is completed by briquette drying or electric drying for about 7 days.

The conventional dried persimmon manufacturing method described above not only requires a long time of 25 to 30 days, but also the drying conditions, such as temperature, humidity, wind speed, etc., vary greatly depending on the weather, so the drying state of the persimmons depends on the drying conditions at that time. It is affected by weather conditions, and the quality and shipping time of dried persimmons fluctuate accordingly.

For example, the time to dry fresh persimmons is usually from November to December, but in years when the temperature is high and there is a lot of rain during that period, rotten fruits and
When the dried persimmons are removed, they often develop fruit and mold, which significantly reduces the quality and yield of dried persimmons. On the other hand, in years when the temperature is low, the after-ripening effect of persimmons does not progress sufficiently, resulting in poor removal of astringency, and astringency remains in dried persimmons. In addition, in this case, the color of the dried persimmons is not constant, and instead of the amber color that would be considered an excellent product, the fruit becomes yellow-orange, resulting in a significant deterioration in quality.

On the other hand, some drying methods have been implemented in which fresh persimmons are peeled and then stored in an air flow dryer equipped with a dehumidifier and a heater. In this case, the temperature, humidity, wind direction, and flow velocity distribution of the air at the drying air supply port of this dryer may be inappropriate, or
As a result of insufficient control, the initial drying speed increases, the surface of the persimmon during drying hardens, and the moisture inside becomes difficult to evaporate, resulting in the chestnut color of dried persimmon products turning dark or turning yellow-orange. Its quality often deteriorates.

Furthermore, since the drying speed becomes excessive, continuous drying cannot be carried out, and body drying is required during the drying process, making the work complicated and reducing efficiency.

[Problem that the invention seeks to solve]

As mentioned above, with conventional solar drying, the drying of persimmons is greatly influenced by natural conditions, and as a result, the quality of dried persimmons is unstable.
Furthermore, the drying time was extremely long and the efficiency was low. On the other hand, the conventional method of producing dried persimmons using a dryer also suffers from deterioration in quality, the drying work is complicated, and the work efficiency is not necessarily good.

An object of the present invention is to overcome the above-mentioned problems and provide a method for producing dried persimmons that can improve the quality, uniformity, and yield of dried persimmons, save labor, and shorten the drying period. It is.

[Means for solving problems]

The means of the present invention for solving the above problems is to store a large number of peeled raw persimmons in a drying chamber, and to dry the raw persimmons by flowing a drying air flow into the drying chamber from a supply port. In the manufacturing method, the temperature of the drying air stream at the supply port is set to 22
~30°C, relative humidity 40-85%, average flow rate 0
．． A method for producing dried persimmons characterized by performing initial astringency removal drying of the raw persimmons in the air for a controlled period of 2 to 1.17 seconds, and in this method, the flow direction of the drying air flow is directed upward. It is.

[For production]

As mentioned above, the present invention performs initial astringent drying of raw persimmons by controlling temperature and
This is carried out in an air stream with humidity and wind speed controlled within a certain range, and this was discovered by the inventor as a result of research and experiments.

In the present invention, raw persimmons after peeling are placed in an air stream so that they do not come into contact with each other. The raw persimmons to be dried are generally hung in pairs tied together with strings placed inside the drying chamber. Air with controlled temperature, humidity, and wind speed (air volume) is sent into the drying room from a separate room through a supply port.

The temperature and humidity control range at the supply port is 22-30℃,
Set the ratio to 40-85% depending on the ripeness of the raw persimmons. For example, in the case of Sanja persimmons, the ripeness of raw persimmons is classified into three stages according to chestnut color and hardness as shown below, and temperature and humidity are controlled according to each ripeness level.

J, Ru *2 Magnesterra hardness tester 5/16 inch Temperature and humidity have a large effect on product quality, and at temperatures below 20°C, the cumulative temperature required for initial astringency removal drying (temperature x drying time)
It takes too long to obtain 2,300-2,500°C time. Furthermore, temperatures exceeding 30°C are not preferable because fermentation begins inside the raw persimmon.

In addition, if the humidity is less than 40%, the drying speed becomes too fast, resulting in deterioration in quality such as blackening of the product dried persimmon due to the surface effect of the raw persimmon. In addition, if the humidity exceeds 85%, mold tends to grow and the yield of dried persimmon products decreases significantly.

Next, the wind speed of the air flow at the supply port is preferably 0.2~
What is necessary is just to control between 1 m/sec, more preferably 0.3-0.5 m/sec. At a wind speed of less than 0.2 m/sec, mold is likely to grow, and the yield of dried persimmon products is significantly reduced.

In addition, if the wind speed exceeds 1 n/sec, the drying speed becomes too fast, resulting in deterioration in quality such as blackening of the dried persimmon product due to the surface effect of the raw persimmon. Moreover, it is not economically preferable since the equipment cost is increased.

If the direction of the airflow is a crosswind, the resistance of the raw persimmon will be large;
Vertical air flow is preferable because the raw persimmons are swayed horizontally, resulting in misalignment of the persimmons and the phenomenon of "threading" in which the hanging strings get stuck in the persimmons, causing mold to grow in those areas and resulting in lower yields. In addition, when comparing the moisture content of the bottom and top of a persimmon, the top has a higher moisture content than the bottom, so in order to dry the same fruit uniformly, the conditions must be such that the top of the fruit dries more easily than the bottom. Preferably, therefore, the direction of air flow is longitudinal and opposite to the direction of gravity (upwards).

The initial drying of fresh persimmons according to the present invention is preferably completed when the weight of fresh persimmons reaches about 65% of the dry weight, and then dried by charcoal briquette drying, sun drying, etc. to reach 30% of the dry weight. When the weight reaches a certain level, it can be considered as a dried persimmon product.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

EXAMPLE This example is based on a combination of the method described herein and briquette drying using Sanja persimmons. As shown in FIG.
There are 27 to 28 sets of bamboo poles 2 for each pole, i.e., 54 to 56 I attached several fresh persimmons.

The fresh persimmons attached to the bamboo poles were arranged so that they did not touch each other.

The raw persimmons attached to these three drying carts were subjected to initial astringency removal drying by the method of the present invention using a drying device 7 having a three-chamber structure shown in FIGS. 3 and 4. This drying device 7 is equipped with a hot air heater 10, an air conditioner 12, and a fan 11 in the machine room 8.
The drying room 7a is divided into two parts: a machine room 7a in which the drying cart 1 is installed and a drying room 7b in which the drying cart 1 is placed. The drying room 7b has a drying partition wall 9a)
~9b) is further divided into three parts. One drying trolley 1 is placed in each room, and the air inside the machine room is adjusted to a temperature of 30°C and a relative humidity of 70% using a hot air heater and an air conditioner.
was supplied to the drying room. The air was an upward flow blown out from the floor of the drying room and discharged from the ceiling, and was controlled at an average wind speed of 0.4 ml/sec. Raw persimmons are dried in this drying room (
The product was dried to a percentage of 65% (weight after drying/dry load amount) x 100, ie, a dry weight ratio of 65%, and then dried with charcoal briquettes to a dry weight ratio of about 30% and shipped as a product. or,
This example was conducted at the same time as Comparative Example 1, and the weather during drying was the same as Comparative Example 1.

In the figure, 13 indicates a cooler attached to the air conditioner, I4 indicates a duct rectifying plate, and 15 indicates a rectifying plate.

Figure 5 shows the dry weight ratio of fresh persimmons to the number of drying days. Here, the solid line shows the initial astringency removal drying by the method of the present invention, and the broken line shows the change in dry weight-V ratio with respect to the number of drying days when briquette drying is performed subsequent to the method of the present invention. Astringency removal is completed at a dry weight ratio of 65%, but in the method of the present invention, the fifth
As you can see from the figure, it will be completed in 3 days. In addition, heating to 30°C promotes the after-ripening effect, and the time required for the maroon color (RH5), which is an indicator of the progress of the after-ripening effect, to reach 28-A is 3 days after the start of reprinting. there were. Moreover, in the conventional method, the drying time is 48 to 60 minutes after the start of drying, which has a high risk of mold growth.
1 time! No mold was observed at all even after passing through it.

Note that no rest work was performed for 3 days after the start of drying.

Subsequent briquette drying was carried out at 25°C for 20 hours, then 1
The body was dried for 2 hours and further dried at 25° C. for 20 hours to give a dry weight ratio of 45%. At this point, knead your hands 2
The process of leaving for 4 hours, drying at 23° C. for 8 hours, and drying for 16 hours was repeated 4 times to obtain a product with a final dry weight ratio of 30%. The quality of the product at this time was excellent 93.5
, excellent quality was 6.5%, and no products with quality below good quality were found.

As described above, by performing the initial astringency removal drying of fresh persimmons by the method of the present invention, the astringency removal drying process was completed in about 173 days compared to the initial drying by solar drying shown in Comparative Example 1. Therefore, there are advantages of labor saving and stable shipping time. Moreover, the product manufactured in this example is of excellent quality.
There are only excellent products and there are no inferior products, and there is a high proportion of excellent products, so compared to the method of Comparative Example 1, the product quality is improved and more uniform, and the yield is also higher. has been proven. Furthermore, from the results of Comparative Example 2, it is more desirable that the flow direction of the air flow is upward.

Comparative Example 1 This example combines initial astringency removal drying by solar drying and charcoal briquette drying. After peeling, raw persimmons are hung from bamboo poles 2 as shown in Figure 2, and then hung on tiers in a well-ventilated glass greenhouse.
Initial drying to remove astringency was performed by drying in the sun. The initial astringency removal drying was completed when the dry weight ratio of raw persimmons reached 65%, and the drying was then completed by charcoal briquette drying until the dry weight ratio was 30%. FIG. 6 shows the dry weight ratio of fresh persimmons to the number of drying days in this comparative example. Here, the solid line indicates the initial astringency removal drying by sun drying, and the broken line indicates the change in dry weight ratio with respect to the number of drying days when briquette drying was subsequently performed.

As can be seen from FIG. 6, it took nine days in this comparative example to reach a drying ratio of 65%, which is more than three times the time required by the method of the present invention in Example 1. At this point, the accumulated temperature was insufficient and the astringency had not been completely eliminated.On the other hand, the weather was favorable with no rain for more than three days in a row, so there was no mold growth.

Thereafter, briquette drying was carried out, and a product having a dry weight ratio of 30% was obtained. The quality of the product at this time was excellent, 76.3%.
The percentage was 22.9% for excellent products and 0.8% for non-defective products.

Comparative Example 2 In this example, the number of rooms in the drying device was changed from a royal room to one room. Fresh persimmons were dried under the same conditions as in Example 1, except that the flow direction of the air flow was a horizontal flow blowing out from the right side wall and discharging to the left side wall.

In this example, mold grew in the center of the middle stage of the drying cart 48 hours after the start of drying.

〔Effect of the invention〕

As explained above, the present invention improves and uniformizes the quality of the product dried persimmons by controlling the temperature, humidity, and flow rate of the drying air to optimal conditions during the initial astringency-removal drying of raw persimmons. The occurrence of mold, rotten fruit, and peeling is reduced and the yield is improved. Moreover, since the method allows for continuous drying, there is no need to take a break during the drying process, resulting in labor saving and shortening of drying time.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a drying trolley used in carrying out the present invention, Fig. 2 is a side view showing how to attach raw persimmons, and Fig. 3 is an example of an apparatus carrying out the present invention. FIG. 4 is a cross-sectional view along the line A-A in FIG. 3, and FIG. 5 is a graph showing the ratio of dry weight to drying days in drying raw persimmons using the method of the present invention combined with briquette drying. FIG. 6 is a graph showing changes in the dry weight ratio with respect to the number of drying days in drying raw persimmons using a combination of sun drying and charcoal briquette drying. 1---Drying trolley, 2---Bamboo pole, 38~3
e==bamboo rod holder, 4---wheel, 5---thread, 6---
...Persimmon fruit, 7-----Drying device, 7a...Machine room, 7b--Drying room, 8--Partition wall, 9a, 9b - ...Drying room partition wall, 10-...
...Hot air heating machine, 11...Fan, 12
−−−−−Air conditioner, 13... Cooler attached to air conditioner, + 4−... Duct, 15...
·rectifier.

Claims (1)

[Claims] 1. A dried persimmon production method in which a large number of peeled raw persimmons are housed in a drying chamber, and a drying air flow is introduced into the drying chamber from a supply port to dry the raw persimmons, The temperature of the drying air stream at the supply port is 22-30°C, and the relative humidity is 40-85°C.
%, and the average flow velocity is controlled to 0.2 to 1.0 m/sec, and the raw persimmon is dried to remove initial astringency in the air. 2. The method for producing dried persimmons according to claim 1, wherein the drying air flow is directed upward.