JPS63304941A - Preparation of vegetable or fruit snack food - Google Patents

Abstract

PURPOSE:To prepare a dried snack food of vegetables or fruits in short time at a low cost, stably keeping the color tone, shape, taste and flavor of the raw material, by subjecting thin slices of vegetables or fruits to a secondary drying process comprising irradiation of microwave and then to a finish drying process comprising drying with far infrared radiation. CONSTITUTION:Slices of vegetables or fruits are dried to a water-content of 15-60% by primary drying. The dried slices are further dried and expanded by secondary drying comprising the irradiation of microwave. Finally, the product is dried by far infrared radiation to a water-content of <=5% to obtain the objective dried snack food of vegetables or fruits having light and crisp feeling to the teeth and free from oil.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing snack foods based on vegetables and fruits. According to the present invention, it is possible to make vegetables or fruits into oil-free snack foods that have excellent color tone, flavor, shape, etc., and have a crispy and light texture.

[Conventional technology]

Conventional methods for drying foods include sun drying, hot air drying,
Vacuum drying, freeze drying, microwave drying, deep-frying, etc. are known, but if these methods are used alone under their normal conditions, ideal quality snack foods containing vegetables or fruits as the main ingredients cannot be produced. can't get it.

For this reason, most of the vegetable or fruit snacks currently on the market are those that are deep-fried under reduced pressure.In addition, there are methods in which the above-mentioned conventional drying methods are carried out under special conditions, and there are also methods in which the above-mentioned conventional drying methods are carried out under special conditions. Methods for using them in combination have been proposed. JP-A No. 61-265046 describes a method of drying fruit or vegetable slices by freezing them and heating them by irradiating them with microwaves under reduced pressure. This method essentially consists of a one-step vacuum microwave drying method, using freezing of the raw material as a starting condition and microwave heating as a later condition; the three-step method of the present invention is completely (Different.

JP-A-56-109546 discloses that fruit chips are dried by freeze-drying until the moisture content becomes 15 to 60% by weight,
Next, the moisture content is reduced to 10-40% by vacuum microwave drying.
The moisture content is reduced to 5.
% or less is described. This publication clearly states that the desired dry chips cannot be obtained by any other method, and does not at all suggest the method of the present invention, which uses far-infrared drying as the final drying step.

[Problem that the invention seeks to solve]

The prior art methods have the following problems: In the case of vacuum frying, oil remains in the dried product, resulting in a strong taste and high calorie content.

There are also concerns about oil oxidation, which poses problems in long-term storage. In the case of the freeze vacuum microwave drying method, it is essential to start the vacuum microwave treatment in a frozen state, but because the material to be dried is thin, a portion of the material may dry during the process from the freezing process to the vacuum microwave treatment process. There is a risk of melting. Furthermore, microwave irradiation under reduced pressure poses a risk of glow discharge, and furthermore, it is difficult to use continuously and requires a lot of labor. On the other hand, the three-step method of freeze drying, vacuum microwave drying, and vacuum drying takes several hours to complete due to freeze drying, and the equipment used in the three types of drying processes are all pressure resistant. Since it must be a device, a large amount of equipment cost is required. Also, since it is difficult to serialize, it requires a lot of manpower.

Therefore, the present invention overcomes the drawbacks of conventional drying methods and produces oil-free dried vegetable or fruit snacks that retain the color, shape, and flavor of the raw materials and have a crispy, light texture in a relatively short period of time. The aim is to provide a method that can be obtained at low cost.

[Means for solving problems]

As a means to solve the above-mentioned problems, the present invention firstly dries thin slices of vegetables or fruits dipped in a soaking liquid to a moisture content of 15 to 60%, if necessary, and then performs secondary drying in a micro-microwave. To provide a method for producing a vegetable or fruit snack food, characterized by drying and swelling flakes by irradiating waves, and then performing far-infrared drying as final drying until the moisture content of the flakes becomes 5% or less.

[Action and effect]

In the drying process of the present invention, primary drying is first performed by a commonly used drying method that does not require reduced pressure or vacuum, such as far infrared drying.
Since it is not a complete drying process as it is carried out until the drying process reaches 5 to 60%, there is almost no discoloration of the raw material or deterioration of the taste or aroma that would occur if the freeze-drying was carried out halfway. The next drying process, the microwave drying process, needs to be carried out under reduced pressure, as ice crystals are not localized (therefore uneven distribution of moisture) and residual moisture is evenly distributed throughout the raw material pieces. The final drying of the present invention is carried out by a far-infrared drying method, which provides the following effects.

(1) Far infrared rays promote mutual chemical reactions between ingredients such as sugars and amino acids contained in raw materials, as well as impregnated carbohydrates and seasonings. It has the function of quickly and effectively expressing the above.

(2) There is less destruction of pigment components such as chlorophyll and carotene in raw vegetables or fruits, and as a result, the color of the finished snack is bright.

(3) Generally, when vegetables and fruits lose water, their tissues become soft, shrink, and become severely warped. However, when drying with far infrared rays, these deformations are slight, and as a result, they remain porous and have a good shape. Finished with texture.

According to the method of the present invention, oil-free vegetable or fruit snacks with excellent color, shape, flavor and texture can be obtained in a relatively short time and at low cost.

Furthermore, although it is effective to carry out the three-stage drying method of the present invention in a batch manner, it is also easy and equally effective to adopt a conveyor continuous production line process method.

[Specific explanation]

In the method of the present invention, any vegetables and fruits that are commonly used as raw materials for snack foods can be used as raw materials. Examples of vegetables include carrots, kapocha, rennin, green peppers, onions, burdock, etc.; As such, apples, bananas, kiwis, oysters, etc. can be used.

An example of the steps of the method of the invention can be illustrated as follows.

Each of these steps will be explained in detail below.

mkudanfuku In this process, the raw vegetables or fruits are cut into 1 to 8 pieces thick.
Cut into thin pieces, preferably 1 to 5 mm. If the slice thickness is too thick, it will take a long time to dry, making it more likely that undesirable phenomena such as softening and browning will occur during drying, making it difficult to obtain a desirable texture as a snack. On the other hand,
If the slice thickness is too thin, defects will easily occur during slicing.
Also, the strength of the dry product is low (easily damaged).

Blanching is a process of inactivating enzymes in raw materials to prevent changes such as discoloration, discoloration, and tissue softening caused by enzymes during drying.

The heating temperature and heating time must be determined based on the thickness of the slice, the type of vegetable or fruit, the region of origin, the season, the degree of ripeness, etc., but in general, it is desirable to process the food in as short a time as possible.
Usually, it is appropriate to carry out the heating at 80 to 100°C for about 10 seconds to 5 minutes.

ΩW By immersing sliced vegetables and fruits in soaking liquid, the yield of vegetables and fruits with low solid content can be improved and ￥
Carbohydrates are impregnated to strengthen the IJi texture, and seasonings are impregnated to make the flavor of the dried product desirable as a snack.

A mixed aqueous solution of carbohydrates and seasonings is suitable for the dipping liquid. The carbohydrates used here include simple substances such as glucose! Kind, Sea II! Other examples include oligosaccharides, sugar alcohols, polysaccharides such as dextrin and starch, or mixtures thereof. Note that the total concentration of these carbohydrates is suitably 5 to 30%. Further, as seasonings, appropriate amounts of soy sauce, salt, spices, chemical seasonings, vinegar, alcoholic beverages, etc. may be added depending on the compatibility with the target vegetables and fruits.

The soaking time varies depending on the type and thickness of the vegetable or fruit, and the temperature of the soaking liquid, but it is usually preferably about 10 minutes to 2 hours.

The moisture content of the raw material flakes after intensive soaking varies slightly depending on the type of vegetables or fruits and the concentration of dissolved components such as carbohydrates in the soaking liquid, but is approximately 80%.

This is dried by primary drying until the moisture content becomes 15 to 60%, preferably 20 to 40%.

Various known drying methods such as hot air drying can be used for this drying. It is also possible to use a water-absorbing agent such as a polymeric water-absorbing sheet. However, chlorophyll, carotene, etc.
Compared to other drying methods, the destruction of the pigment components and nutritional components such as vitamins in raw vegetables or fruits is slight, and there is less shrinkage or warping of the tissue, and it can be heated quickly and uniformly from the inside, so it can be dried in a short time. It is preferable to use a far infrared drying method that can process
Electromagnetic waves in the range of 0 μm are preferable, and metal oxide ceramics containing zirconia, titania, alumina, etc. as components can be used as the radiator. The drying conditions for far infrared drying are as follows: Radiator surface temperature: 150-300°C Distance between the radiator and the object to be dried: 10-25 am Atmospheric temperature
A temperature of 60 to 100°C is suitable. The time required varies depending on the type and thickness of the raw vegetables or fruits, but is usually 5 to 30 minutes.
It's a minute.

If this primary drying treatment is not performed at all, or if it is performed insufficiently, then raw material flakes with a moisture content of 60% or more are subjected to microwave treatment, resulting in partial discoloration or scorching and drying uniformly. Moreover, the bubbles formed on the surface are uneven in size and have an unsightly appearance.

On the other hand, if raw material flakes that have been subjected to excessive primary drying, that is, raw material flakes with a moisture content of 15% or less, are subjected to microwave treatment, the result is a snack food with poor texture due to insufficient swelling and hard texture.

(The vegetable or fruit flakes that have undergone the primary drying process are then dried by microwave drying until the moisture content reaches 6-15%.During this process, the flakes swell and bubbles form on the surface. When the moisture content after drying is more than 15%, sufficient swelling will not occur.
Furthermore, the time required for the next step, far-infrared finishing drying, becomes longer. On the other hand, if it is less than 6%, the flavor of the raw material will be impaired and charring will likely occur. Although the amount of microwave irradiation varies depending on the type, thickness, etc. of the raw material flakes, conditions are generally suitable such that water evaporates at an average rate of 0.1 to 0.6 g/sec per 100 g of raw material flakes.

6. Top 7.) Finish drying using far infrared rays is performed for the purpose of reducing the moisture content of vegetable or fruit flakes to 5% or less.

The far infrared rays used may be the same as in (4) primary drying,
The conditions are: heater surface temperature: 150 to 300 degrees Celsius; distance between the heater and the object to be dried; lO to 25 oa; ambient temperature
A temperature of 40 to 90°C is suitable. The time required varies slightly depending on the type and thickness of the raw vegetables or fruits, but usually 5 to 1
It is 0 minutes. If this finishing drying is done excessively, the flakes will become discolored or burnt, and if insufficiently done, they will lack the snack-like flavor.
As for the texture, it doesn't end up being crispy or light.

Group 1 - 1 Carrots were peeled and sliced into 2 to 3 thick slices. After blanching 1 kg of this flake by holding it in a vortex at 90°C for 2 minutes,
．． 5%, soy sauce 7.5%, chili pepper 0.1%, and monosodium glutamate 0.05% (all weight%)
The sample was immersed in 2 kg of an aqueous solution containing the following for 30 minutes at room temperature.

After dipping, put the thin piece into a far infrared dryer and heat the heater to 23°C.
It was dried for 20 minutes at 0° C., the distance between the heater and the flake was 20 CII, and the atmospheric temperature in the dryer was 80° C. After this primary drying, the moisture content of the carrot slices was 25%.

The flakes were then transferred to a microwave dryer with an output of 180
The flakes were irradiated with microwaves of W until the moisture content of the flakes reached 12%.

The flakes obtained in this way are put into the far-infrared dryer again,
Heater temperature 230℃, distance between heater and flake 20aII,
It was dried for 10 minutes at an ambient temperature of 80° C. in the dryer to obtain 122 g of dried carrot snacks with a moisture content of 3.1%.

1 Comparison N-Top Example 1. The carrot slices that had been soaked in the same manner were placed in a hot air dryer and dried at 80°C for 95 minutes until the moisture content was 3.2.
131 g of dried carrot snacks were obtained.

Tatsunami ■-1 Example 1. Carrot slices that have been soaked in the same manner as above are
℃, 110 Torr for 6 minutes, followed by 125℃, 5 minutes
Vacuum frying was performed at Torr for 7 minutes to obtain 152 g of dried carrot snacks with a moisture content of 2.7% and an oil content of 17%.

The three types of carrot snacks obtained in Example 1, Comparative Example 1, and Comparative Example 2 were sensory evaluated by 12 panelists, and the results are shown in the table below.

Kapocha was cut lengthwise into appropriate widths (maximum 3a1) and sliced into 1.5-2 cm thick pieces. After blanching 1.8 kg of this flake by holding it in boiling water for 10 seconds, it was mixed with 10% soy sauce, 7.5% dextrin, and 7.5% sigm.
The samples were immersed for 1 hour at room temperature in 3.5 kg of an aqueous solution containing 5% red pepper, 0.2% chili pepper, and 0.05% sodium glutamate (all percentages by weight).

This immersed thin piece was placed in a far infrared dryer, and the heater temperature was 20.
0℃, distance between heater and flake! 15 am, and dried for 10 minutes at an atmospheric temperature of 100° C. in the dryer. After this primary drying, the moisture content of the Kapocha flakes was 38%.

Next, this flake was transferred to a microwave dryer with an output of 500
W was irradiated with microwaves until the moisture content of the flakes reached 9%.

The flakes obtained in this way were placed in the far-infrared dryer again and dried for 6 minutes under the conditions of a heater temperature of 200°C, a distance of 15cm between the heater and the flakes, and an atmospheric temperature of 70°C in the dryer. 475 g of snacks were obtained.

1 Cliff 1 An apple was peeled, cut into quarters, and the core was removed and sliced into thin slices with a thickness of 4.5 to 5 cm. 800g of this thin piece
Dextrin 5%, Shi! 1115%, and salt 0.9
% (all percentages by weight) of an aqueous solution containing 1.5%
The eyes were immersed for 10 minutes at room temperature.

The soaked apple slices were placed in a far-infrared dryer and dried for 30 minutes at a heater temperature of 180°C, a distance between the heater and the slice of 1ii1101, and an atmospheric temperature in the dryer of 60°C. After this primary drying, the moisture content of the apple slices was 41%.

The flakes were then transferred to a microwave dryer with an output of 180
The flakes were irradiated with microwaves of W until the moisture content of the flakes reached 14%.

The apple flakes obtained in this way were put into the far infrared dryer again, the heater temperature was 150°C, the distance between the heater and the flakes was 10 mouths,
It was dried for 10 minutes at an atmospheric temperature of 50° C. in the dryer to obtain 98 g of dried apple snacks with a moisture content of 3.0%.

S1"L" After peeling the rennin, it was cut into rounds with a thickness of 1.5 to 2 m.

After blanching 1 kg of this flake by holding it in hot water at 90°C for 30 seconds, add 10% white sugar and 7.5% soy sauce.
%, vinegar 5%, chili pepper 0.2%, and sodium glutamate 0.05% (all percentages by weight) in an aqueous solution containing 2 kg for 2 hours at room temperature.

This immersed thin piece was placed in a hot air dryer and dried for 25 minutes at an atmospheric temperature of 90° C. inside the dryer. After this primary drying, the moisture content of the lotus root flakes was 29%. Next, the flakes were transferred to a microwave dryer and irradiated with microwaves with an output of 500 W until the moisture content of the flakes was 6%.

Finally, put this thin piece into a far infrared dryer, and the heater temperature is 2.
It was dried for 8 minutes at 50° C., the distance between the heater and the flake was 11,120 cm, and the atmospheric temperature in the dryer was 90° C. to obtain 201 g of dried lotus root snacks with a water content of 2.3%.

Urajogo-1 A green pepper was cut into rounds with a thickness of 5 pieces, the inner seeds were removed, and 500 g was kept in boiling water for 1 minute to perform blanching. After this, add this green pepper ring to 10 pieces of white sugar.
%, soy sauce 5%, monosodium glutamate 0.05%
(all percentages by weight) was immersed in 1.1 kg of an aqueous solution at room temperature for 30 minutes.

Place the soaked green pepper rings in a far-infrared dryer, set the heater temperature to 230°C, and set the distance between the heater and the green pepper rings ii! 1
20 cm, and was dried for 22 minutes at an atmospheric temperature of 90° C. in the dryer. After this primary drying, the moisture content of the green pepper rings is 36%.
Became.

Next, this semi-dried green pepper ring was transferred to a microwave dryer, and irradiated with microwaves with an output of 180 W until the moisture content of the ring became 11%.

The thus obtained green pepper rings were placed in the far-infrared dryer mentioned above again and dried for 5 minutes at a heater temperature of 230°C, a distance of 20cm between the heater and the ring, and an ambient temperature of 90°C in the dryer, resulting in drying with a moisture content of 4.6%. Green pepper snack 59g
I got it.

Claims (1)

[Claims] 1. Primary drying of vegetable or fruit slices to reduce moisture content to 15
It is characterized by drying until the moisture content of the flakes reaches ~60%, then drying and swelling the flakes by irradiating them with microwaves as secondary drying, and then performing far-infrared drying as final drying until the moisture content of the flakes becomes 5% or less. A method for producing a vegetable or fruit snack food. 2. The method for producing a vegetable or fruit snack food according to claim 1, wherein the primary drying is far-infrared drying. 3. The method for producing a vegetable or fruit snack food according to claim 1, characterized in that all of the drying steps are performed under normal pressure.