KR102378507B1 - Appratus for manufacturing roast sweet potato - Google Patents

Abstract

An object of the present invention is to provide a method for preparing roasted sweet potatoes that can minimize the leakage of moisture from the inside of the sweet potato when thawing for ingestion, thereby maintaining the same taste, aroma and texture as that of freshly baked sweet potatoes. The present invention for this purpose is a heating step of heating the sweet potato to make roasted sweet potato; A quick freezing step of freezing the heated roasted sweet potatoes at a temperature of -35 to -45°C for 20 to 40 minutes; and a packaging step of packaging the quick-frozen roasted sweet potato.

Description

Roasted sweet potato manufacturing method {APPRATUS FOR MANUFACTURING ROAST SWEET POTATO}

The present invention relates to a method for preparing roasted sweet potatoes, and more particularly, to a method for preparing roasted sweet potatoes capable of maintaining the taste, aroma and texture of sweet potatoes after thawing.

Sweet potato is a dicotyledonous edible crop belonging to the Convolvulaceae and is native to Central and South America. It was first introduced to Korea in 1796 and has been used as a food resource for a long time. It is widely cultivated throughout the country.

These sweet potatoes are high in carbohydrates and can be substituted as a staple food. They are rich in fiber, vitamin C, vitamin E, potassium, thiamine, iron, etc., and beta-carotene and ganglioside have anticancer effects. It is also known to help reduce the risk of lung cancer. In particular, it is well-known as one of the well-being health foods with effects on diet and constipation prevention, and its consumption is actively made by all age groups of all ages.

Sweet potatoes have the disadvantage of being sensitive to temperature because they are weak to cold, and also, because they are weak to humidity and light, there is a difficulty in storage because they have to be stored in a well-ventilated shade at a temperature of 12~15℃. In addition, the conventional method of ingesting sweet potatoes is limited to raw, steamed sweet potatoes, roasted sweet potatoes, etc. depending on the cooking type. Except for this period, there is a problem that it cannot be easily eaten.

For this reason, sweet potatoes were recognized as a food eaten only in winter. However, as described above, efforts are being made to develop a storage method and processing method of sweet potato as various physiological effects of sweet potato are recently known and recognized as a health functional food for weight control.

As one of the roasted sweet potato manufacturing methods, recently, methods for storing sweet potatoes by rapidly cooling after roasting have been developed, but these must be kept frozen for distribution and must be thawed when consumed. Moisture seeps out and the quality of the appearance of the roasted sweet potato is deteriorated, such as being crushed, and you can feel a sense of rejection due to a foreign body feeling in the process of ingestion. There is a problem of degradation.

Republic of Korea Patent Publication No. 10-1548204 (2015.08.31. Announcement)

An object of the present invention is to solve the problems of the prior art, and the present invention minimizes the leakage of moisture from the inside of the sweet potato when thawing for ingestion, and maintains the same taste, flavor and texture as that of freshly baked sweet potato. It is to provide a method for manufacturing roasted sweet potatoes that can be

In order to achieve the object of the present invention described above, the roasted sweet potato manufacturing method according to an embodiment of the present invention selects sweet potatoes with a size of 3 cm to 5 cm, and maintains 100% relative humidity of the selected sweet potatoes at a temperature of 30° C. 5 A pretreatment step of curing for one day, washing the cured sweet potato, naturally drying the washed sweet potato, and aging the dried sweet potato in a low-temperature warehouse at a temperature of 15° C. for 30 days; A heating step of heating the sweet potato that has undergone the pretreatment step at a temperature of 250° C. for 40 minutes to make roasted sweet potato; A cooling step of cooling the skin area of the roasted sweet potato so that the temperature of the skin area of the roasted sweet potato maintains a temperature of at least 80 °C by supplying air cooled to a preset temperature to the roasted sweet potato that has undergone the heating step; A processing step of half-cutting the roasted sweet potato in the thickness direction, and inserting an additive into the inner space of the cut roasted sweet potato, which is performed before the temperature of the roasted sweet potato that has undergone the cooling step falls below 80° C.; A rapid freezing step of rapidly freezing the roasted sweet potatoes that have undergone the processing step at a temperature of -40°C for 30 minutes; and a packaging step of packaging the roasted sweet potato that has undergone the rapid freezing step; the heating step includes a water supply step of supplying moisture to the sweet potato being heated so as to increase the moisture content of the roasted sweet potato and shorten the heating time at the same time characterized in that

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The roasted sweet potato manufacturing method according to the present invention minimizes the phenomenon and the amount of moisture seeping out during thawing, thereby solving the problem that the thawed roasted sweet potato is crushed or the flesh and skin are not well separated, and above all, raw It is possible to provide the consumer with the same taste, aroma and texture as if the sweet potato was baked just before.

In addition, the roasted sweet potato manufacturing method according to the present invention can also improve long-term storage, so that the shelf life can be prolonged, and there is also an advantage that can minimize the change in quality even when stored for a long time.

1 is a flowchart of a roasted sweet potato manufacturing method according to an embodiment of the present invention.
2 is a flowchart of a pre-processing step according to an embodiment of the present invention.
3 is an exemplary view of a cooling unit for cooling roasted sweet potatoes in the cooling step according to an embodiment of the present invention.
4 is a view showing roasted sweet potatoes prepared according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention in which the above-described problems to be solved can be specifically realized will be described with reference to the accompanying drawings. In describing the present embodiments, the same names and the same reference numerals are used for the same components, and an additional description thereof is omitted.

1 is a flowchart illustrating a method for manufacturing roasted sweet potatoes according to an embodiment of the present invention, and FIG. 2 is a flowchart illustrating a pre-processing step according to an embodiment of the present invention.

The roasted sweet potato manufacturing method according to the present invention may include a pretreatment step (S10), a heating step (S20), a cooling step (S30), a processing step (S40), a quick freezing step (S50) and a packaging step (S60). there is.

The pre-treatment step (S10) is a step of primarily processing the raw sweet potato harvested previously in the heating step (S20) of baking the harvested sweet potato into roasted sweet potatoes according to the purpose of use, and the pre-treatment step (S10) according to the embodiment is selected It may include a step (S11), a curing step (S12), a washing step (S13), a drying step (S14) and an aging step (S15).

The selection step (S11) is a step of selecting the best raw sweet potato by state and size for the harvested raw sweet potato, and it is possible to select a sweet potato with poor quality such as an appearance or select a sweet potato within a predetermined size range with marketability.

For example, sweet potatoes of poor quality are not only rotten sweet potatoes, but also sweet potatoes that have been crushed or sprouted, or sweet potatoes whose growth is slow due to drought or harvested too late, such as sweet potatoes whose cores such as tough tree trunks are found in large quantities inside. Falling sweet potatoes are selected.

In addition, in the predetermined size range, the size of the sweet potato is selectively selected within the range of 3 to 10 cm depending on the intended use for children's feeding, youth feeding, and general household use. The sweet potato corresponding to the size of 3 cm or less or 10 cm or more may have a problem in that the quality of the roasted sweet potato may deteriorate, such as burning or undercooking in the heating step and rapid freezing step to be described later.

The curing step (S12) is a step of providing conditions for the sweet potato to breathe in order to heal the wounds of the sweet potato generated during the harvesting process for the sweet potato having commercial value through the selection step (S11).

Curing is the original meaning of treatment, and it improves storage properties by treating wounds of sweet potatoes during harvesting or transporting sweet potatoes. : It is treated with the formation of a newly formed shell). That is, the secondary epidermis (Peroderm) formed just below the wounded epidermis of the sweet potato develops into a new epidermal tissue and forms a cork layer to heal the wound. Sweet potatoes cured in this way can suppress the weight loss rate and suppress the occurrence of mold and erosion during long-term storage.

Curing conditions according to the embodiment are suitable to be carried out for 4 to 7 days while maintaining 90 to 100% relative humidity at a temperature of 28 to 32 ℃. These curing conditions can control the relative humidity and time according to the size, type (pumpkin sweet potato, golden sweet potato, etc.) of the selected sweet potato, and the temperature at harvest.

As described above, the sweet potato cured for 4 to 7 days at a temperature of 28 to 32 ° C and 90 to 100% relative humidity could suppress the weight loss by about 30% and maintain the bright color of the skin of the sweet potato, It can also suppress the occurrence of mold and erosion by more than 10 times.

The washing step (S13) is a step of removing foreign substances such as soil from the skin of the cured sweet potato through the curing step (S12). Or it can be carried out by sprinkling.

The drying step (S14) is a step of drying the sweet potato that has been washed through the washing step (S13). It can be naturally dried at room temperature in the shade with good ventilation, and is forced in a warehouse where a constant temperature is maintained using a separate ventilator. It can also be dried.

The aging step (S15) is a step of aging the dried sweet potato through the drying step (S14) at a temperature close to room temperature for a predetermined time. For reference, mature fruits such as mango, avocado, banana, melon, pineapple, kiwi, etc. As in the case of sweet potatoes, the best color and taste quality can be achieved by going through a predetermined aging period at room temperature rather than refrigerated storage after harvest.

Aging conditions according to the embodiment are recommended to be aged for 30 days in a shaded warehouse where 15 ℃ is maintained.

For example, in the season when the temperature is higher than 15 ℃, the aging period of 30 days can be maintained in a low-temperature warehouse where 15 ℃ is maintained, and 15 ℃ is maintained in a specific season when the temperature close to 15 ℃ is maintained, which is the sweet potato harvest time. It can be naturally aged for 30 days in a well-ventilated shade.

Contrary to these ripening conditions, if sweet potatoes are unavoidably stored for a long time at a temperature below 15° C., ethanol and acetaldehyde components increase inside the sweet potatoes, destroying the cell walls inside the sweet potatoes, and they can be easily spoiled.

The heating step (S20) is a step of heating the aged sweet potato through the aging step (S15) to make roasted sweet potato, and the heating condition according to the embodiment may be made at a temperature of 240 to 260° C. for 30 to 50 minutes.

The heating conditions for 30 to 50 minutes at the 240 to 260 ° C. may be adjusted within the above range depending on the size of the sweet potato, and in this case, in the case of the sweet potato selected to be 3 to 5 cm in size, the heating condition is at 250 ° C. for 40 minutes. It can be thoroughly cooked deep inside by heating it while it is being heated.

When the heating temperature is less than 240° C., it takes more than 50 minutes to ripen to the depths, and as the internal temperature of the sweet potato gradually rises over a long period of time, the cells and cell walls exposed to high temperatures for a long time are destroyed, and a large amount of them in the cell tissue of the internal liquid is discharged and evaporated. After the freezing process to be described later, when thawing for ingestion, a large amount of water is discharged from the destroyed cells and tissue, resulting in a decrease in the taste and nutrition of roasted sweet potatoes.

In addition, when the heating temperature is higher than 260° C., the skin portion is excessively burned before being fully cooked to the depth of the inside of the sweet potato, resulting in lowering the taste and quality of the roasted sweet potato.

As a result, roasted sweet potatoes, which are produced through heating conditions for 30 to 50 minutes at a temperature of at least 240 to 260° C., are heated with high-temperature heat in a relatively short time to destroy cells and cell walls and harden cell tissues before moisture is evaporated. As such, the moisture retained by the cell tissue is maintained as it is. After the freezing process to be described later, when thawing for ingestion, the taste, texture, flavor and nutritional status of roasted sweet potatoes, such as those that have been roasted just before raw sweet potatoes, can be improved.

The apparatus for heating may include a heater, and a heating member may be further provided so that the heat source of the heater is effectively transmitted to the sweet potato and supports the sweet potato being heated.

The heater may be an electric heater or a heater using wood or charcoal as a heating source, and a member having excellent thermal conductivity such as a grill, wire mesh, plate-shaped elvan or ceramic may be used as the heating member. As a result, as the heater is heated, the heating member is also heated, and by arranging the sweet potato on the heating member, the whole sweet potato can be uniformly heated and cooked. In addition, even if the heater does not continuously maintain heat, it can cook sweet potatoes more efficiently because the retained heat is continuously maintained.

On the other hand, the heating step (S20) may include a water supply step, and the water supply step is a step of supplying moisture to the sweet potato being heated so that the moisture content of the roasted sweet potato fruit part can be increased and the heating time of the roasted sweet potato can be shortened.

At this time, the supplied moisture may be heated to a preset temperature, and may be boiling water of 100°C.

The apparatus for supplying moisture may simply provide a container filled with water inside the heater, or may continuously supply moisture for a preset time and number of times during heating by arranging a sprayer at the upper end of the heater.

If moisture is supplied to the sweet potato being heated in this way, the moisture evaporates quickly so that it can be uniformly applied to the entire skin of the sweet potato, and since the high-temperature moisture is applied to the skin of the sweet potato, the heating time of the roasted sweet potato can be greatly shortened. .

And, since it is possible to maintain an appropriate moisture content in the fruit part of the roasted sweet potato made through the heating step (S20), the sweetness of the roasted sweet potato can be increased, and the skin can be easily peeled off from the fruit part.

The cooling step (S30) is a step of cooling the freshly made roasted sweet potato through the heating step (S20), and the surface skin region of the freshly made roasted sweet potato can be cooled, and the cooling step (S30) for this is cooled to a preset temperature. While supplying fresh air, the skin area of roasted sweet potato can be cooled quickly.

3 is an exemplary view showing a cooling unit in which roasted sweet potatoes are cooled. Referring to FIG. 3 , the cooling step ( S30 ) of roasted sweet potatoes may be performed in the cooling unit 30 , and the cooling unit 30 is a chamber 31 . ), a transfer conveyor 32 and a blowing unit 33 may be included.

The chamber 31 may provide a cooling space in which roasted sweet potatoes are cooled.

At least a portion of the transfer conveyor 32 may be disposed to pass through the cooling space of the chamber 31 . That is, roasted sweet potatoes may pass through the cooling space of the chamber 31 while moving from one side of the transfer conveyor 31 to the other. The transfer conveyor 31 may be formed in a mesh shape, and thus, the entire surface of the roasted sweet potatoes mounted on the transfer conveyor 31 may be exposed on the cooling space of the chamber 31 including the bottom portion.

The blowing unit 33 may include a blowing duct, and the blowing duct may be disposed at an upper end of the chamber 31 . Compressed air cooled to a preset temperature through a heat exchanger (not shown) may be supplied to the cooling space of the chamber 31 through a blowing duct, and may be sprayed onto roasted sweet potatoes being transported.

As such, in the cooling step (S30), while passing through the heating step (S20), cooling air is sprayed on the freshly made roasted sweet potato while rapidly cooling only the surface skin area except for the fruit part of the roasted sweet potato. It can be easily peeled off, and the time of the rapid freezing process of roasted sweet potatoes in the rapid freezing step (S50) performed later can be shortened.

And, in the cooling step (S30), by cooling the peel region of the roasted sweet potato, it is possible to easily perform a processing process of inserting an additive into the inside of the roasted sweet potato, which is performed immediately afterwards.

In this cooling step (S30), the temperature of the fruit portion of the roasted sweet potato that has been subjected to the heating step (S20) performed above is maintained as it is, but only the temperature of the surface skin region is dropped below a certain temperature, preferably the cooling step (S30) ), the temperature of the surface skin area of the roasted sweet potato can be maintained at a temperature of at least 80℃.

For example, when the temperature of the peel area of the roasted sweet potato falls below the temperature of 80 ° C, the internal liquid remaining inside begins to ooze out to the surface of the roasted sweet potato, and in this state, the processing step (S40) and When the rapid freezing step (S50) is performed, the roasted sweet potato becomes crushed when thawing for subsequent consumption, the peeling of the flesh and skin is not easy, and the original taste may also be deteriorated.

The processing step (S40), which may be performed after the cooling step (S30), is a step of increasing the taste quality of roasted sweet potatoes and adding additional additives in consideration of the consumer's taste. This processing step (S40) is cut It may include a processing step and a participant insertion step.

The cutting processing step is a step of forming an internal space by cutting the prepared roasted sweet potato in half in the thickness direction. The whole can be cut in the longitudinal direction of the roasted sweet potato, and only the central part can be cut to form an internal space. there is.

The additive insertion step is a step of inserting an additive into the internal space of the roasted sweet potato cut through the cutting and processing step, and the additive is consumed with roasted sweet potatoes such as cheese, butter, mustard, various sauces, and seasoning. It may be ready-to-eat food. These additives can increase the taste when ingested with roasted sweet potatoes, and any additives that can maintain a frozen state for a long time can be used. However, additives that have similar thawing conditions to the conditions of thawing roasted sweet potatoes for consumption by consumers (within a few minutes in a microwave oven with power consumption of 1000 W) are preferable.

This processing step (S40) is preferably performed immediately immediately after passing through the previously performed heating step (S20) and cooling step (S30) in sequence. That is, it is better to carry out before the temperature of the roasted sweet potato falls below a certain temperature, and preferably, it is good that the cutting process and the additive insertion process are completed before the temperature of 80 ° C. or less falls.

For example, the temperature of a hot roasted sweet potato starts to cool slowly from room temperature, and if the temperature drops below 80℃, the internal liquid remaining inside begins to seep out to the surface of the roasted sweet potato, and in this state, the liquid If the quick-freezing process described below is performed, the roasted sweet potatoes may become crushed when thawed for subsequent consumption, and the peeling of the flesh and skin may not be easy.

The quick freezing step (S50) is a step of rapidly freezing the roasted sweet potato that has undergone the processing step (S40), and the quick freezing condition according to the embodiment is 20 to 40 at a temperature of -45 to -35°C using rapid cooling. It can be quick-frozen in minutes.

The conditions of rapid freezing for 20 to 40 minutes at the -45 to -35 ° C temperature can be adjusted within the above range depending on the size of the roasted sweet potato, for example, in the case of a sweet potato selected to a size of 3 to 5 cm - It can be flash frozen at a temperature of 40° C. for 30 minutes.

Although it depends on the size of the sweet potato, in general, sweet potatoes selected within the range of 3 to 5 cm can be completely frozen within 20 to 40 minutes at a temperature of -45 to -35°C.

In addition, rapid freezing is possible even at a temperature lower than -45℃, but the time it takes for sweet potatoes to be completely frozen is not much different from the process of rapid freezing at -40℃, and consumes a lot of power compared to the effect.

On the other hand, when rapid freezing is performed at a temperature higher than -35°C, that is, in the conventional freezing process, gentle freezing is performed at a temperature of -35 to -25°C. However, in the case of foods with a lot of moisture, such as roasted sweet potatoes, when the moisture remaining inside forms ice crystals in the cell tissue, the volume increases as the moisture freezes, destroying the cell wall or creating a large gap between cells. to form ice crystals.

The ice crystals formed between the vertical and the cells in this way damage the cell wall surrounding the cells, and when thawed, drips occur in the damaged cell tissue, thereby improving the taste and quality of the product. This results in loss of nutrition as well as color and shape.

Also, even when roasted sweet potatoes containing moisture are frozen, when the moisture evaporates and becomes steam, the temperature of steam decreases and frost occurs in the food. The quality is deteriorated, such as the peeling of the flesh and skin is not easy.

In addition, when roasted sweet potatoes are freeze-dried and the surface becomes porous, the space for connection with air increases, which causes problems such as oxidation of fat, denaturation of protein, discoloration, and deterioration of taste and flavor.

After all, the roasted sweet potato, which is rapidly frozen for 20 to 40 minutes at the -45 to -35 ℃ temperature according to the embodiment, is rapidly frozen through the temperature range of the maximum ice crystal formation zone (-1 ℃ ~ -5 ℃). By performing this, the cell and cell wall are prevented from being destroyed, and the moisture retained by the cell tissue during the freezing process is maintained as it is, so that it is not crushed when thawing for ingestion, and the peeling of the skin from the flesh can be performed uniformly as a whole. , it is possible to reduce the amount of dripping of moisture generated during thawing, so it is possible to provide the taste, texture, and aroma of roasted sweet potatoes that are the same as roasted sweet potatoes before freezing.

The packaging step (S60) is a step of packaging the roasted sweet potatoes that have been rapidly frozen through the rapid freezing step (S50). can be individually packaged. On the other hand, the packaging step (S60) may be a vacuum packaging step, and by vacuum packaging, it is possible to prevent the roasted sweet potatoes containing additives from coming into contact with oxygen, thereby maintaining quality and preventing spoilage.

After the packaging step (S60) is performed, it may further include a freezing storage step. The freezing storage step according to the embodiment may be stored in a freezer maintaining a temperature of -30 to -20°C for roasted sweet potatoes including packaged additives. The shelf life of roasted sweet potatoes can be further extended by continuously maintaining the frozen storage stage for these quick-frozen roasted sweet potatoes.

Roasted sweet potatoes stored in a freezer that maintains a temperature of -30 to -20°C in this way can be shipped according to the shipment request of the ordering party.

Experimental Examples 1 to 4 below are comparative examples of roasted sweet potatoes prepared according to Examples of the present invention, and roasted sweet potatoes were prepared by different heating conditions for preparing roasted sweet potatoes and frozen conditions of the prepared roasted sweet potatoes, [Table 1] shows the overall results of the prepared roasted sweet potatoes, such as appearance, taste, texture, peeling, and preference.

<Example 1>

Selection step (S11): selecting raw sweet potatoes with a size of 3 to 5 cm.

Curing step (S12): Curing for 5 days at 100% relative humidity at a temperature of 30 ℃.

Washing step (S13) and drying step (S14): natural drying after washing.

Aging step (S15): Aged for 30 days in a 15 ℃ low-temperature warehouse.

Heating step (S20): Prepare roasted sweet potatoes by arranging aged sweet potatoes on a grill and heating them at 250° C. for 40 minutes using an electric heater.

Rapid freezing step (S50): Rapid freezing at -40 ℃ temperature for 30 minutes.

<Example 2>

Prepared in the same manner as in Example 1, except that the aged sweet potato in the heating step (S20) was arranged on a grill and heated at 180° C. for 50 minutes using an electric heater to prepare roasted sweet potato.

<Example 3>

Prepared in the same manner as in Example 1, but proceeded with freezing for 60 minutes at a temperature of -25 degrees in the rapid freezing step (S50).

<Example 4>

Prepared in the same manner as in Example 1, except that the ripened sweet potato in the heating step (S20) is arranged on a grill and heated at 180° C. for 50 minutes using an electric heater to prepare roasted sweet potato, and the rapid freezing step (S50) ) at -25 degrees Celsius for 60 minutes.

division Exterior taste texture peel off symbol Example 1 9 9 8 8 8 Example 2 8 7 7 7 8 Example 3 9 7 7 6 7 Example 4 7 6 6 5 6

The above [Table.1] was prepared based on the opinions of 30 tasting groups randomly selected from men and women of all ages who tasted the roasted sweet potatoes prepared in Examples 1 to 4, and within the range of the lowest score of 1 to the highest score of 10. was written

In addition, in Examples 1 to 4, all roasted sweet potatoes that were frozen and stored in a low temperature warehouse at 18° C. for 10 days were thawed and tasted.

First, if Example 1 and Example 2 are compared, the temperature difference during heating is confirmed to have a slight difference in appearance, texture, peeling and preference, and it can be seen that it particularly affects the taste difference. In addition, considering the fact that the age groups of men and women of all ages are not taken into account, it can be seen that only minute differences in appearance, texture, peeling and preference have an effect.

In addition, comparing Example 1 and Example 3, the temperature difference during rapid freezing, it was confirmed that there was no difference in appearance, but a significant difference in taste, texture, peeling and preference overall was confirmed.

In addition, when Example 1 and Example 4 were compared, when the heating and rapid freezing temperatures were all set differently, the overall appearance, taste, texture, peeling, and preference were also significantly different.

Although the preferred embodiment of the present invention has been described with reference to the drawings as described above, those skilled in the art may vary the present invention in various ways without departing from the spirit and scope of the present invention as set forth in the claims below. may be modified or changed.

Claims (7)

Sweet potatoes with a size of 3 cm to 5 cm are selected, and the selected sweet potatoes are cured at a temperature of 30° C. while maintaining 100% relative humidity for 5 days, and the cured sweet potatoes are washed, and the washed sweet potatoes are dried naturally. A pre-treatment step of aging the dried sweet potato in a low-temperature warehouse at a temperature of 15° C. for 30 days;
A heating step of heating the sweet potato that has been subjected to the pre-treatment step at a temperature of 250° C. for 40 minutes to make roasted sweet potato;
A cooling step of cooling the skin area of the roasted sweet potato so that the temperature of the skin area of the roasted sweet potato maintains a temperature of at least 80 ℃ by supplying air cooled to a preset temperature to the roasted sweet potato that has undergone the heating step;
A processing step of half-cutting the roasted sweet potato in the thickness direction, and inserting an additive into the inner space of the cut roasted sweet potato, which is performed before the temperature of the roasted sweet potato that has undergone the cooling step falls below 80° C.;
A rapid freezing step of rapidly freezing the roasted sweet potatoes that have undergone the processing step at a temperature of -40°C for 30 minutes; and
Including; packaging step of packaging the roasted sweet potato that has undergone the rapid freezing step;
The heating step is a roasted sweet potato manufacturing method, characterized in that it comprises a moisture supply step of supplying moisture to the sweet potato being heated so that the heating time is shortened at the same time as increasing the moisture content of the roasted sweet potato. delete delete delete delete delete delete

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