JP3066492B2 - Method for producing steamed dried sweet potatoes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing steamed and dried sweet potatoes.

[0002]

2. Description of the Related Art Steamed and dried sweet potatoes, which are traditional processed foods called dried, steamed, and imosumome, have been produced mainly by farmers working in the home. In this process, sweet potatoes are washed, steamed, peeled, cut to a thickness of 5 to 8 mm, spread on a blade, and air-dried for several days to finish the product. In addition, there is one which steamed small plums as a whole and dried to make dried persimmons.

[0003] The value of steam-dried sweet potato as a product depends on its meat color, meat quality and taste. The flesh color is yellow or yellowish-white, and those that are transparent to the so-called amber color are treated as excellence. It is essential that the meat is not too hard, and a suitable chewy texture is preferred. It is desirable that the taste be strong in sweetness. The quality of such a product is basically determined by the variety of the sweet potato, which is the raw material, but it depends largely on the quality of the processing method.

[0004] Conventionally, the production of steamed and dried sweet potatoes is often carried out by the farmer's in-house production, and the processing is dependent on manual labor, so the labor productivity is low and the food hygiene is low. However, the conditions are not necessarily preferable. Moreover, since the drying process depends on the sun and natural wind, it is difficult at present to always obtain a homogeneous and high-quality product.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a homogeneous and high-quality product having all of the meat color, meat quality and taste required for steamed and dried sweet potatoes.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, by controlling the temperature control environment in the drying process of the steamed and dried sweet potato, a homogeneous and high quality product is obtained. The product was successfully obtained, and the present invention was completed.

[0007] That is, the present invention is a method for producing steam-dried sweet potatoes, wherein the sweet potatoes are steamed and then alternately dried with two types of dry air having different temperatures. The present invention is also a method for producing a steamed and dried sweet potato, which comprises steaming the sweet potato and then continuously drying it with heated dry air. Hereinafter, the present invention will be described in detail.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The variety of sweet potato used as a raw material in the present invention is not particularly limited, but "Tamayutaka" which has been typically used in the past for producing steamed dried sweet potato is preferred. In the present invention, sweet potatoes that are not cut but remain in the shape of the potato are referred to as “round potatoes”, which include small potatoes such as “Tamayutaka” and “Kyushu
No. 121 is suitable, and a sweet potato cut into a flat plate shape is called a "flat potato", which includes large potatoes such as "Tamayutaka" and "Kyushu 118".
No. is suitable.

[0009] After washing, peeling and steaming the above sweet potato, the sweet potato is left as a whole or cut and then subjected to drying. In the case of a round shape, the shape of the sweet potato is adjusted to, for example, a cylindrical shape, a spindle shape, a cocoon shape, or the like so that the sweet potatoes have substantially the same size and weight. Also,
When cutting, the sweet potato is cut into, for example, a disc shape, a spindle flat plate shape, and a rectangular flat plate shape so as to have substantially the same size and weight.

[0010] In the present invention, the sweet potato prepared as described above is alternately dried with two types of dry air having different temperatures. Of the two dry air temperature ranges, the high temperature range is 40-60 ° C, preferably 45-50 ° C, and the low temperature range is 0-15 ° C, preferably 5-10 ° C.
Drying with dry air in each temperature range is performed alternately several times for 6 to 12 hours, preferably for 8 to 10 hours, for example, 12 times in total.
It is performed for 0 to 160 hours, and the total amount of the alternate drying time can be appropriately adjusted depending on the variety and form of the sweet potato.

[0011] In another embodiment of the present invention, the sweet potato prepared as described above is continuously dried by heating and drying air. The temperature range of heating and drying air is 40-60 ° C, preferably 45-50 ° C
Drying with dry air at the temperature is performed continuously, for example, for 48 to 72 hours, preferably 56 to 60 hours. The total amount of the continuous drying time can be appropriately adjusted depending on the variety and form of the sweet potato.

"Steamed dried sweet potato" produced by the above method
When the moisture content is "round", it is 18-21%, when it is "flat", it is 19-23%, and when the penetration resistance is "round", it is 500-1000MPa, In the case of "Potato", it is 200-500MPa, and can exhibit excellent quality characteristics (flesh color, meat quality, taste).

[0013] Any of the above methods can be adopted for the production of steamed and dried sweet potatoes of the present invention, but the former alternate drying method using two types of dry air having different temperatures is important for obtaining high quality products with respect to quality characteristics. It is suitable, and the latter continuous drying method using heated drying air can be said to be suitable for obtaining a product in a short time with some sacrifice of quality characteristics, so it may be appropriately adopted depending on its purpose and implementation situation. . In addition, the temperature range of the dry air used in the above method is the ambient temperature in each case, and therefore it is desirable to use ultraviolet irradiation together from the viewpoint of suppressing the propagation of various bacteria.

[0014]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. [Example 1] (Production of rounded steamed dried sweet potatoes) After washing, peeling and steaming sweet potatoes ("Kyushu No. 121"), the same size and shape were obtained to obtain a homogeneous product (shown in Fig. 3). Cylindrical, spindle-shaped, cocoon-shaped, etc.), weight (one piece weighs 30-50)
g). This was spread so as not to overlap on a plastic scale, dried in an incubator with dry air at 45 ° C. for 8 hours, and then repeatedly dried in dry air at 10 ° C. for 8 hours for 7 days (168 hours). FIG. 1 shows changes over time in the water content and the penetration resistance. FIG. 2 shows the changes over time in the water content and the penetration resistance when the sweet potato prepared in the same manner as above was continuously dried in dry air at 45 ° C. for 7 days (168 hours). As shown in FIG. 1, in the former alternate drying using two types of dry air having different temperatures (hereinafter, referred to as an alternate drying method), the water content gradually decreases, and the penetration resistance gradually increases accordingly. . It took 6 to 7 days to reach 800 to 900 MPa, which is an appropriate hardness as a texture, and the water content at that time was about 20% (wet basis). The product at this time had a candy color, and had a good mochi-like texture and sweetness. On the other hand, as shown in FIG. 2, in the latter continuous drying using heated drying air (hereinafter, referred to as a continuous drying method), both the moisture content and the penetration resistance have a steep change ratio as compared with the alternating drying method. It is appropriate hardness
It takes only three days to reach 800 to 900 MPa, but a locally hard part is formed and the flesh color is inferior to the alternate drying method. Therefore, it can be said that the alternate drying method is suitable for obtaining a high-quality product in which the quality characteristics are important, and the continuous drying method is suitable for obtaining the product in a short time while sacrificing some of the quality characteristics.

[Example 2] (Manufacture of sweet potato steam-dried sweet potato) After washing, peeling and steaming sweet potato ("Kyushu No. 118"), the same size and shape (about It is cut into a 10 mm-thick disk-shaped, spindle-plate-shaped, rectangular-plate-shaped, etc. as shown in FIG. 3) and weighed (one piece weighs 20 to 35 g). This was spread on a plastic scale so as not to overlap, and after drying in an incubator with 45 ° C. dry air for 8 hours, drying with 10 ° C. dry air for 8 hours was repeated for 3 days (72 hours). FIG. 4 shows changes over time in the water content and the penetration resistance. FIG. 5 shows the changes over time in the water content and the penetration resistance when the sweet potato prepared in the same manner as above was continuously dried in dry air at 45 ° C. for 3 days (72 hours). FIG.
As shown in (1), in the former alternate drying method, the water content gradually decreases, and the penetration resistance gradually increases accordingly. In addition, as shown in FIG. 5, in the latter continuous drying method, the moisture content decreases sharply as compared with the alternating drying method, and the penetration resistance reaches 1300 MPa on the third day. It has exceeded 1100MPa. Since the appropriate hardness for a flat plate is 300 to 400 MPa, the product can be dried and dried in 3 days by the alternate drying method and 2 days by the continuous drying method.

[0016]

According to the present invention, steamed dried sweet potatoes having excellent color tone, texture and sweetness can be provided. Further, according to the present invention, the manufacturing process can be put under hygienic quality control, and a high-quality, value-added product can be provided.

[Brief description of the drawings]

FIG. 1 shows the change over time in the water content and penetration resistance of round and steam-dried sweet potatoes in alternate drying with two types of dry air at different temperatures.

FIG. 2 shows time-dependent changes in water content and penetration resistance of round and steam-dried sweet potatoes in continuous drying with heating and drying air.

FIG. 3 is a diagram showing an example of the shape of a steamed product to be used for drying.

FIG. 4 shows changes over time in the water content and the penetration resistance of flat potato steam-dried sweet potatoes in alternate drying using two types of dry air at different temperatures.

FIG. 5 shows the change over time in the water content and penetration resistance of flat-dried potato steam-dried sweet potatoes in continuous drying with heating and drying air.

Claims (3)

(57) [Claims] 1. A method for producing steam-dried sweet potatoes, wherein the sweet potatoes are steamed and then alternately dried with two kinds of dry air having a temperature range of 40 to 60 ° C. and 0 to 15 ° C. 2. The method for producing steam-dried sweet potatoes according to claim 1, wherein the alternate drying with two kinds of dry air is performed at intervals of 6 to 12 hours. 3. The method according to claim 1, wherein the steamed sweet potato is formed into the same size, shape and weight.