JP2013063031A - Method of producing roasted nut by superheated steam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing roasted nuts by superheated steam which is capable of continuously producing roasted nuts without break or crack, wherein the roasted nuts obtained are especially tasty.SOLUTION: The roasted cashew nuts are produced without discharging the superheated steam 7 from openings (an inlet 4 and an outlet 5) of a roast chamber 1 when continuously roasting cashew nuts P carried into the roast chamber 1 of an open system by a conveyor 6, with the superheated steam 7 jetted from above and below the cashew nuts P.

Description

  The present invention relates to a method for producing roasted nuts by superheated steam.

  Conventionally, roasting of nuts represented by walnuts, almonds, peanuts, cashew nuts and the like has been regarded as one of important processes for determining the flavor and quality. At present, roasting nuts are mainly performed by equipment using hot air, combustion gas, far infrared rays, microwaves, etc., and roasted nuts on the market are manufactured by any of these equipments. Has been. In recent years, roasting with superheated steam has begun to be studied for further improvement in flavor and quality. In other words, superheated steam has a larger amount of heat than normal steam, so it can be processed in a short time, and superheated steam surrounds nuts during processing, making it possible to make the environment almost oxygen-free. Therefore, it is expected that the flavor and quality can be improved.

  To roast nuts with such superheated steam, for example, a roasting apparatus as described in Patent Document 1 can be used. This is a peanut that is put into a rotating drum through a roasted product inlet while rotating with stirring blades, and overheated steam heated to several hundred degrees by a superheater is injected and roasted. is there. According to this roasting apparatus, the oxidation of lipids by roasting is suppressed, the storage stability is improved, and roasted peanuts excellent in sterilizing effect can be obtained.

JP 2002-209566 A

  However, in order to produce roasted peanuts using the roasting apparatus of Patent Document 1, superheated steam is blown into the rotating drum with a blower to create a pressurized atmosphere in the rotating drum. There is a need. In such a case, the roasting apparatus becomes large, and the roasting operation becomes a batch type. Further, the roasting apparatus is roasted while stirring and rotating peanuts, and thus has a drawback that cracks and chips are generated in the peanuts due to the impact.

  The present invention has been made in view of such circumstances, and is a method for producing roasted nuts by superheated steam, which can be manufactured continuously and without cracking or chipping. In particular, an object of the present invention is to provide a method for producing roasted nuts by superheated steam with a good flavor of roasted nuts.

  In order to achieve the above object, according to the method for producing roasted nuts with superheated steam of the present invention, a nut transfer conveyor is provided in the roasting chamber for roasting nuts across the inlet and outlet of the roasting chamber. A roasting apparatus using superheated steam provided with superheated steam jet holes provided above and below the runway for transferring nuts located in the roasting chamber is provided. A drainage port for discharging water derived from the superheated steam is provided at the lower part of the heating chamber, a ventilation port is provided at the upper part of the roasting chamber, and nuts are placed on the runway of the conveyor to put the nuts in the roasting chamber. Continuously carrying in and injecting superheated steam into the nuts from the superheated steam injection holes provided above and below the runway, and the action of the vent and the excess water derived from the superheated steam from the drain Eliminate By the action of, as its gist to roasting the nuts without let out almost superheated steam from the inlet and outlet of the roasting chamber.

  That is, the present inventors have made extensive studies in order to solve the above problems. In the course of that research, I thought that if the nuts could be roasted in an open system, the roasting operation could be performed efficiently in a continuous manner, and further research was conducted. As a result, in the roasting chamber for roasting nuts, a superheated steam sprayer is provided, and a drain outlet for discharging water derived from the superheated steam is provided at the bottom of the roasting chamber of the roasting device, and If a ventilation port is provided at the top of the roasting chamber, the gas volume in the roasting chamber will decrease and the pressure in the roasting chamber will drop when the superheated steam sprayed on the nuts changes into liquid (water). It has been found that the superheated steam in the roasting chamber hardly leaks out from the inlet and outlet, and the roasting chamber can be opened. Further, at that time, if the excess water generated above is discharged from the drain outlet as needed, it can be prevented that the water adheres to the nuts and inhibits roasting, and the water generated above is heated. It was also found that when saturated water vapor is generated and discharged from the ventilation port, this saturated water vapor can be prevented from adhering to the nuts and inhibiting roasting, and the present invention has been achieved.

  As described above, the method for producing roasted nuts using superheated steam according to the present invention is provided with a nut transfer conveyor in the roasting chamber for roasting nuts across the inlet and outlet of the roasting chamber. Can be continuously carried in and out of the roasting chamber, so that roasted nuts can be produced continuously and efficiently. In addition, since the superheated steam jet holes are provided toward the runway above and below the runway for transferring nuts located in the roasting chamber, only the amount of nuts to be carried in, the roasting time, etc. are adjusted. Thus, roasted nuts in a uniform roasted state can be produced. Therefore, the operation and apparatus for stirring and rotating nuts, which has been conventionally used for obtaining a uniform roasted state, is not required, and it is possible to prevent the nuts from being cracked or chipped due to the impact caused by the stirring and rotating operation. In addition, a drain outlet for discharging water derived from the superheated steam is provided in the lower part of the roasting chamber, and a ventilation port is provided in the upper part of the roasting chamber, so that the injected superheated steam hits the nuts and is liquid (water ), The gas volume in the roasting chamber is reduced, the pressure in the roasting chamber is lowered, the superheated steam in the roasting chamber is hardly discharged from the inlet and outlet, and the surplus generated above Water can be discharged at any time from the drain outlet, so that this water can be prevented from adversely affecting roasting by attaching to the nuts, etc., and the water generated above is heated and saturated steam is generated. Since it can be discharged from the ventilation port, it is possible to prevent this saturated water vapor from adhering to the nuts and adversely affecting roasting. Therefore, roasted nuts with good flavor can be produced continuously and efficiently, not batchwise.

  Among them, when the superheated steam is sprayed onto the nuts in a state where the temperature in the roasting chamber is set to 150 to 260 ° C., the original flavor of the nut can be further enhanced, and a roasted nut having a rich flavor is obtained. be able to.

  In addition, when superheated steam having a temperature 20 to 100 ° C. higher than the temperature in the roasting chamber is used for jetting superheated steam to the nut, the aromatic flavor of the obtained roasted nut can be further increased, and the nut itself Because it is possible to extract the sweetness of the roasted nuts, it is possible to obtain roasted nuts having an unprecedented sweetness and fragrant aroma.

  And since the food texture of the obtained roasted nut can be lightened as the roasting time with respect to the said nut is 3 to 10 minutes, the roasted nut of the unprecedented food texture can be obtained.

  Furthermore, when the amount of steam of superheated steam sprayed onto the nut is 0.80 to 12.0 kg / h, color unevenness does not occur on the surface of the roasted nut, and a roaster that exhibits a more uniform color is obtained. You can get roasted nuts.

  In the present invention, “nuts” means all edible nuts covered with hard shells, including walnuts, almonds, peanuts, cashews, pistachios, macadamia nuts, brazil nuts, hazelnuts and piccan nuts.

It is explanatory drawing for demonstrating the outline of the roasting apparatus used for one embodiment of this invention, Comprising: It is explanatory drawing which shows the state which opened the door (not shown) provided in the side surface of the apparatus and opened below. . It is a horizontal sectional view for explaining the superheated steam generator of the roasting apparatus. It is a graph which shows the conditions and the result in the verification experiment 2 of the said roasting apparatus.

  Next, an embodiment for carrying out the present invention will be described. However, the present invention is not limited to this embodiment.

  The method for producing roasted nuts using superheated steam according to the present invention can be summarized as follows: nuts are carried into an open-type roasting chamber by a conveyor, and the superheated steam is almost continuously from the open portion of the roasting chamber. This is a method for producing roasted nuts without going outside. Hereinafter, a cashew nut will be described as an example of the nut. In addition, the cashew nut is used in a state where the shell (shell fruit) has already been peeled off and only the seed (seed) is obtained.

  FIG. 1 is an explanatory diagram showing an outline of a roasting apparatus used in an embodiment of the present invention. A roasting chamber 1 for roasting cashew nuts P and saturated steam 2 are generated to the roasting chamber 1. A saturated steam generator 3 to be supplied and a conveyor 6 for transporting the cashew nut P from the inlet 4 to the outlet 5 of the roasting chamber 1 are provided. The roasting chamber 1 heats the saturated steam 2 supplied from the saturated steam generator 3 to generate superheated steam 7, and the generated superheated steam 7 toward the cashew nut P. Upper and lower superheated steam injection pipes 9 provided with jetting outlets 9a, a discharge port 10 for discharging water derived from the superheated steam 7, and a ventilation port 11 are provided.

  More specifically, the roasting chamber 1 is formed in a box shape, the inlet 4 and the outlet 5 are formed on the left and right side walls, and the inside is always open. The conveyor 6 is a belt-type conveyor, and the horizontal direction of the roasting chamber 1 is the traveling direction (longitudinal direction), and the traveling surface of the traveling path is inserted through the roasting chamber 1. And the inlet 4 of the right end part (right side of FIG. 1) of this conveyor 6 becomes the carrying-in part 13, and the outlet 5 of the left end part (left side of FIG. 1) on the opposite side across the roasting chamber 1 is the carrying-out part 14. It becomes. The belt of the conveyor 6 is made of mesh-like stainless steel, and the superheated steam 7 sprayed from the spray ports 9a of the superheated steam spray pipes 9 provided above and below the roasting chamber 1 is sufficiently applied to the cashew nuts P, respectively. In addition, the air permeability can be kept high so as not to hinder the flow of gas toward the discharge port 10 and the ventilation port 11. The superheated steam injection tube 9 is suspended from a hollow box-shaped superheated steam generator 8 which will be described in detail later, has an oval ring shape, and faces the running surface of the conveyor 6. Further, the return line of the conveyor 6 passes through the lower part of the roasting chamber 1 so as not to be exposed to the outside air in order to suppress heat radiation.

  The saturated steam generator 3 has a boiler body (not shown) and a water supply tank (not shown), generates saturated steam 2 from water, passes through the piping, and the upper and lower portions of the roasting chamber 1. It conveys to the superheated steam generator 8 provided in this. That is, the water supplied from the water supply tank to the boiler main body is heated by the heater in the boiler main body, becomes saturated steam 2, is sent to the superheated steam generator 8, and becomes superheated steam 7, and the upper and lower superheated steam jets. It is injected from the injection port 9a of the tube 9. The piping is provided with a valve (not shown), and the saturated steam 2 may be controlled to be supplied only to the superheated steam generator 8 at either the upper part or the lower part of the roasting chamber 1. it can.

  The superheated steam generator 8 will be described in detail. The superheated steam generator 8 has a thin box shape, and the saturated steam transported from the saturated steam generator 3 as shown in FIG. A plurality of horizontally provided rod-shaped electric heaters 15 for superheating the water vapor 2 and generating the superheated water vapor 7 and meandering pipes 16 extending along the circumference are arranged. The saturated steam 2 is supplied from the start end 20 side of the meandering pipe 16, heated by the electric heater 15, becomes superheated steam 7, and is taken out from the end 21 side of the pipe 16. At this time, since the flow path of the saturated steam 2 is the meandering pipe 16, the superheated steam generator 8 is compact and has high thermal efficiency.

  The extracted superheated steam 7 is injected toward the cashew nut P from the injection port 9a of the superheated steam injection pipe 9 connected to the superheated steam generator 8 (see FIG. 1). The superheated steam spray tube 9 is made of stainless steel and is formed in an oval ring shape that can cover the length direction of the roasting chamber 1 and the belt width of the conveyor 6 in order to uniformly roast the cashew nuts P. A large number of small injection ports 9a are dispersedly provided on the surface of the conveyor 6 facing the running surface of the belt. In addition, it is preferable to provide the injection port 9a in the vicinity of the inlet 4 and the outlet 5 of the roasting chamber 1 because heat dissipation can be reduced by the air curtain effect.

  The discharge port 10 is provided in the central portion of the lower end of the roasting chamber 1 and is connected to the hose 17 so that excess water generated when the superheated steam 7 hits the cashew nut P passes through the hose 17. Then, it is discharged immediately from the roasting chamber 1.

  The ventilation port 11 is provided in the vicinity of the rear end of the upper center of the roasting chamber 1, is connected to the duct 18, and communicates with the outside. As described above, the water generated when the superheated steam 7 hits the cashew nut P is discharged to the outside from the discharge port 10, but a part of the water is vaporized and surplus in the roasting chamber 1. Of saturated water vapor is generated. When excessive saturated water vapor is generated in the roasting chamber 1, it adheres to the cashew nuts P and inhibits uniform roasting. For this reason, the said discharge port 10 discharges | emits excess saturated water vapor promptly. The discharge port 10 also has a function of discharging the superheated steam 7 whose temperature has decreased after hitting the cashew nut P or the like from the roasting chamber 1.

  A metal flat plate 22 is used as a cover on the bottom surface 19 of the roasting chamber 1. The bottom surface 19 adheres to water droplets generated inside the roasting chamber 1 according to gravity. However, since the bottom surface 19 is hot, the adhered water droplets are vaporized again and take heat of vaporization from the bottom surface 19. 19 becomes a low temperature compared with the other surface of the roasting chamber 1. Therefore, when the superheated steam 7 after the action touches the bottom surface 19, it becomes more liquid than the other surface, and the inside of the roasting chamber 1 is made negative by reducing the volume when the gas at that time is liquefied, and the discharge port Combined with the action of 10, the superheated steam 7 is hardly leaked to the outside.

  In order to manufacture roasted cashew nuts using such a roasting apparatus, for example, the following is performed. That is, first, the temperature in the roasting chamber 1 was set to 200 ° C., and the temperature was set to 200 ° C. and the amount of steam 0.865 kg / h (up and down total 1.73 kg / h) from above and below, respectively. The superheated steam 7 is jetted. Next, the transfer speed of the conveyor 6 is set so that the cashew nut P remains in the roasting chamber 1 for about 6 minutes. Then, the cashew nuts P are placed on the belt of the conveyor 6 from the upstream (inlet 4) side carrying-in part 13 so that the grains do not overlap and carried into the roasting chamber 1. Then, the cashew nuts P are heated by the superheated steam 7 having a steam amount of 0.865 kg / h (up and down total 1.73 kg / h) from each of the upward and downward directions while being transported in the roasting chamber 1. It is heated by radiant heat in the roasting chamber 1 (200 ° C.), and is taken out as roasted cashew nuts from the downstream (exit 5) side carry-out portion 14 after about 6 minutes.

  According to this manufacturing method, the cashew nuts P on the conveyor 6 are heated to 200 ° C. with 200 ° C. superheated steam 7 having a steam amount of 0.865 kg / h (up and down total 1.73 kg / h) sprayed from the top and bottom directions, respectively. Because the roasted room 1 is roasted for 6 minutes by the radiant heat in the set roasting room 1, the surface of the obtained roasted cashew nuts does not become uneven, and the interior is roasted evenly and evenly. Can be obtained roasted cashew nuts. Therefore, the operation and apparatus for stirring and rotating the cashew nut P, which has been conventionally used to obtain a uniform roasted state, is not required, and the roasted cashew nut can be obtained at a low cost. It is possible to prevent the occurrence of chipping and chipping and to obtain a beautiful roasted cashew nut with a uniform particle size. Moreover, the superheated steam 7 surrounds the cashew nut P at the time of roasting, and roasting is performed in a state where the oxygen concentration is low. For this reason, the oxidation of the cashew nut at the time of roasting is suppressed, the flavor of the roasted cashew nut obtained is maintained for a long time, and the decrease in the contained nutrients can be suppressed.

  Furthermore, since the drainage port 10 for discharging the water derived from the superheated steam 7 is provided at the lower part of the roasting chamber 1 and the ventilation port 11 is provided at the upper part of the roasting chamber 1, the injected superheated steam 7 is When the cashew nut P changes into liquid (water), the gas volume in the roasting chamber 1 decreases, and the atmospheric pressure in the roasting chamber 1 decreases. For this reason, the superheated steam 7 in the roasting chamber 1 hardly comes out from the inlet 4 and the outlet 5, and the temperature around the roasting device does not rise rapidly, and the roasting operation is performed comfortably. be able to.

  Moreover, since the excess water produced above can be discharged from the drain port 10 at any time, it is possible to prevent this water from adhering to the cashew nuts P and so on, and to prevent the roasting from being adversely affected. Even if heated and saturated water vapor is generated, it can be discharged from the ventilation port 11, so that this saturated water vapor can be prevented from adhering to the cashew nut P and adversely affecting roasting. Therefore, a roasted nut having a flavor that has never been obtained can be produced continuously and efficiently, not in a batch manner.

  In the above-described embodiment, the electric heater 15 disposed in the superheated steam generator 8 is a rod-shaped one. However, other than that, a planar or plate-shaped one may be used. . However, it is preferable to use a rod-like material in terms of good thermal efficiency. Moreover, although the superheated steam generator 8 is provided in two places in the upper and lower sides in the roasting chamber 1, only one of them may be provided, or it may be provided outside the roasting chamber 1. However, if the superheated steam generator 8 is provided in the roasting chamber 1, the heat generated in the superheated steam generator 8 can be used when raising the temperature in the roasting chamber 1, which is efficient. In addition, it is preferable to provide the superheated steam generator 8 at two locations above and below the roasting chamber 1 because the temperature in the roasting chamber 1 can be easily maintained in a more uniform state.

  And in said embodiment, although the bottom face 19 of the roasting chamber 1 is covered with the metal flat plate 22, the shape of this flat plate 22 is a protrusion with a substantially square cross section on the flat plate, or A so-called fin shape in which a number of ridges or the like having a substantially conical section are arranged in parallel may be used to enhance the cooling effect on the bottom surface 19. Further, a circulating water cooler may be attached to the bottom surface 19. In this way, the bottom surface 19 can be cooled more reliably.

  Further, in the above embodiment, the temperature in the roasting chamber 1 when the roasted cashew nuts are obtained is set to 200 ° C., but other temperatures may be set. In particular, when the temperature in the roasting chamber 1 is set to a range of 150 to 260 ° C., more preferably 185 to 235 ° C., the original flavor of cashew nuts can be further enhanced and a roasted cashew nut having a rich flavor can be obtained. it can.

  And in said embodiment, although the temperature of the superheated steam 7 at the time of obtaining roasted cashew nut is set to 200 degreeC, you may make it set to other temperature. Among them, when the temperature of the superheated steam 7 is set to a temperature in the range of 20 to 100 ° C., more preferably 20 to 40 ° C. higher than the temperature of the roasting chamber 1, a roasted cashew nut having a higher fragrant aroma is obtained. Can do. Moreover, since the astringency of cashew nuts is suppressed, the original sweetness can be pulled out more and roasted cashew nuts having an unprecedented sweetness can be obtained.

  In the above embodiment, the roasting time for obtaining the roasted cashew nuts is 6 minutes. However, the roasting cashew nuts are appropriately selected depending on the temperature in the roasting chamber 1, the temperature of the superheated steam 7, the size of the cashew nut grains, and the like. Can be set to a time. Especially, if the roasting time of cashew nut P is 3 to 10 minutes, the inside of the cashew nut P can be roasted firmly, and the texture of the roasted cashew nut obtained can be lightened, making it an unprecedented crispy food A roasted cashew nut with a feeling can be obtained.

  And in said embodiment, although the vapor | steam amount of the superheated steam 7 injected to a nut is 1.73 kg / h (0.865 kg / h from the upper and lower sides respectively), the temperature in the roasting chamber 1 and overheating An appropriate amount of steam can be set according to the temperature of the water vapor 7, the size of the cashew nut grains, and the like. However, if the amount of superheated steam 7 sprayed onto the cashew nut P is in the range of 0.80 to 12.0 kg / h (0.40 to 6.0 kg / h from the top and bottom, respectively), the surface color tone is uneven. Thus, a high-quality roasted cashew nut having a more uniform color tone can be obtained. Further, not only the same amount of superheated steam 7 is injected from the upper and lower sides, but also different amounts of superheated steam 7 may be injected.

  Furthermore, in the above-described embodiment, cashew nuts are used as an example of nuts, but the same effect as cashew nuts can be obtained by using other edible nuts covered with hard shells. Among them, when pistachios, walnuts, cashew nuts, macadamia nuts, brazil nuts, hazelnuts and piccan nuts are used, the astringency of the nuts is suppressed and the sweetness of the nuts increases, so that roasted nuts with a better flavor can be obtained.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to this.

  Prior to studying Examples and Comparative Examples, the following verification experiments 1 and 2 were conducted in order to examine suitable processing conditions for roasting nuts in the roasting apparatus.

<Verification experiment 1: Examination of amount of superheated steam>
The roasting apparatus used in the above embodiment was set to a roasting room temperature of 200 ° C. and a superheated steam temperature of 200 ° C., and the amount of superheated steam (total amount of upper and lower superheated steam) and roasting time are shown in Table 1 below. Roasted cashew nuts were produced under the conditions shown. The results of observing the appearance of the obtained roasted cashew nuts are shown in Table 1. In Table 1, light represents a cream color that is close to raw cashew nuts (the degree of roasting is shallow), and medium has a slightly deep brown color and a so-called fox color (general) Degree of typical roasting). In addition, deep means that the degree of brown is considerably deep and brown (the degree of roasting is deep).

  From the result of the verification experiment 1, it was found that, when roasting for 7.5 minutes or more, a deep color is achieved regardless of the amount of superheated steam. Further, it was found that when the amount of superheated steam was 1.73 kg / h, a shallow color (light) was obtained after roasting for 2.5 minutes. On the other hand, when the amount of superheated steam was large (12.32 kg / h or more), the surface color of the obtained roasted cashew nuts was uneven. Therefore, it was found that when the amount of superheated steam used for roasting is set to a small amount of less than 12.32 kg / h, the surface color tone does not become uneven and the uniformity is improved.

<Verification experiment 2: Examination of roasting temperature and roasting time>
In the roasting apparatus used in the above embodiment, the amount of superheated steam was fixed at 1.73 kg / h, and the roasting room temperature and the superheated steam temperature were in the range of 160 to 300 ° C. The superheated steam temperature was set to the same temperature), and the roasting time was set to a range of 1.0 to 10.0 minutes, and the cashew nuts were roasted under the conditions shown in FIG. The obtained roasted cashew nuts were subjected to sensory tests (color tone, flavor) by 10 panelists who received special training, and evaluated according to the following items. The results are shown in FIG. As a control, a roasted cashew nut (conventional product) roasted at 160 ° C. for 10 minutes using a hot air roasting machine (WR-1000, manufactured by Daitoka Kiken Co., Ltd.), which is one of the conventional methods, was used. .

〔sensory evaluation〕
After randomly picking 30 grains from the roasted cashew nuts obtained, placing them on a white small dish with a diameter of 15 cm, and evaluating their appearance, we selected 3 grains randomly and ate them according to the following items. Evaluation was performed in comparison with the conventional product.
● ・ ・ ・ I feel that the color and flavor are outstandingly superior to the conventional products.
▲ ・ ・ ・ I feel that the color tone and flavor are slightly better than the conventional products, but there is no noticeable difference.
X ... I feel that either or both of the color tone and flavor are equivalent to or inferior to the conventional products.

  From the result of the verification experiment 2, it was found that when the roasting time is 1.0 minute or less, the color tone and flavor are the same as or inferior to those of the conventional product regardless of the roasting room temperature and the superheated steam temperature. Although not shown in FIG. 3, when roasting was performed with the roasting chamber temperature and the superheated steam temperature set to 275 ° C. or higher, a mesh pattern due to the conveyor belt was attached to the cashew nut surface. Furthermore, when the roasting room temperature and the superheated steam temperature were set to 235 ° C. or higher, roasting was performed, the cashew nuts were partially burned even though it seemed that good roasting was performed as a whole. And the sample which performed the roasting for a long time (180 degreeC, 7.5 minutes and 170 degreeC, 10 minutes) and the sample which performed the short time roasting (220 degreeC, 4.0 minutes and 200 degreeC, 6 0.0 minutes), all the 10 panelists answered that the sample roasted for a short time had better flavor, and there was a significant difference between the two.

  Based on the results of the above-described verification experiments 1 and 2, an example of an embodiment of the present invention in which a more suitable production condition for roasted nuts was sought is shown in Examples 1 to 19 below. In addition, roasted nuts obtained by the conventional method (roasting by a hot air roasting machine) and (roasting by a roasting apparatus using superheated steam not provided with an exhaust port and a drain port) are shown as Comparative Examples 1 and 2, respectively.

[Examples 1 to 19]
Roasted cashew nuts were produced in the same manner as in the above embodiment. That is, raw cashew nuts (produced in India) as raw materials are prepared and roasted using the roasting apparatus described above under the conditions shown in Tables 2 to 5 below to obtain the desired roasted cashew nuts. It was. In the roasting, cashew nuts were placed on the conveyor belt so that the grains did not overlap. Moreover, the amount of superheated water vapor was made for the total amount of upper and lower sides to become the amount shown in the table.

[Comparative Example 1]
Roasted cashew nuts were produced by a conventional method. That is, raw cashew nuts (produced in India) as a raw material were roasted at a temperature of 160 ° C. for 10 minutes using a hot air roasting machine (WR-1000, manufactured by Daitoka Kiken Co., Ltd.) to obtain the desired roasted cashew nuts.

[Comparative Example 2]
Roasted cashew nuts were produced by a roasting apparatus using superheated steam that was not provided with an exhaust port and a drain port. That is, roasting was performed under the same conditions as in Example 2 to obtain a target roasted cashew nut.

  The above-obtained roasted cashew nuts (Examples 1 to 19 and Comparative Examples 1 and 2) were each subjected to a sensory test (appearance, color uniformity, aroma, texture, flavor, sweetness) by 10 panelists. The results were evaluated according to the following items and are shown in Tables 2 to 5 below.

[Appearance (color tone)]
The color tone of the entire surface of the obtained roasted cashew nuts was visually observed and evaluated according to the following items.
Deep: The degree of brown is considerably deep and brown (the degree of roasting is deep).
Medium: The degree of brown is slightly deeper and the so-called fox color (general roasting degree).
Light: A cream color similar to raw cashew nuts (lightly roasted).

[Color uniformity]
Thirty grains were randomly taken out from the obtained roasted cashew nuts, placed on a white small dish having a diameter of 15 cm, and the color of the surface of each grain was visually observed and evaluated according to the following items.
A: The same color tone is exhibited as a whole, and no variation is observed.
○: Grains having almost the same color tone but different color tone are recognized in some places. There is almost no variation.
(Triangle | delta): The degree of the grain which is exhibiting a different color tone is a little high. Some variation is recognized.
X: At first glance, variation in the color tone exhibited is recognized.

〔fragrance〕
The scent of 30 cashew nuts used for the evaluation of the uniformity of the color tone was sniffed and evaluated according to the following items.
A: The scent peculiar to fragrant cashew nuts is higher than the conventional product (comparative product 1).
○: The scent peculiar to fragrant cashew nuts is equivalent to the conventional product (comparative product 1).
Δ: The scent peculiar to fragrant cashew nuts is lower than that of a conventional product (comparative product 1) and feels almost odorless.
X: A slightly unpleasant scent different from the conventional product (comparative product 1) is felt.

[Texture]
Three grains were randomly taken out from the roasted cashew nuts obtained, and the feel when chewing them was evaluated according to the following items.
A: The texture is very light compared to the conventional product (comparative product 1) (crisp and light texture).
○: The texture is almost the same as the conventional product (comparative product 1).
X: The texture feels slightly heavier than the conventional product (comparative product 1).

[Flavor]
Three grains were randomly taken out from the obtained roasted cashew nuts, and the flavor (likeness of cashew nuts) when eaten was evaluated according to the following items.
A: The peculiar flavor of cashew nuts is higher than that of the conventional product (comparative product 1).
○: The peculiar flavor of cashew nuts feels equivalent to the conventional product (comparative product 1).
(Triangle | delta): The flavor peculiar to cashew nut is not felt compared with a conventional product (comparative example 1 product).
X: Compared to the conventional product (comparative product 1 product), a slightly unpleasant flavor that is different from the flavor unique to cashew nuts is felt.

[Sweetness]
Three grains were randomly taken out from the roasted cashew nuts obtained, and the taste (sweetness) when eaten was evaluated according to the following items.
A: The sweetness that is not found in the conventional product (comparative product 1) is strongly felt.
○: The sweetness that is not found in the conventional product (comparative product 1) is slightly felt.
Δ: Feels equivalent to a conventional product (comparative product 1).
X: Sweetness is not felt at all, and other flavors (for example, bitterness, astringency, etc.) are felt.

  From these results, it was found that all of the products of Examples 1 to 19 had characteristics not found in conventional roasted cashew nuts. Among them, the one with a superheated steam amount of 1.73 kg / h had a beautifully finished appearance with suppressed variations in color tone. Moreover, what set the roasting room temperature to 190-230 degreeC was able to feel the original flavor of cashew nut more. And the thing which performed roasting for 6 minutes or more had a crispy texture, and was able to enjoy the crispy texture more than before. Furthermore, what set the difference of roasting room temperature and superheated steam temperature within 40 degreeC can raise the scent of roasted cashew nut more, Especially superheated steam temperature is 20-40 from roasting room temperature. It was found that sweetness not found in conventional roasted cashew nuts increased when the temperature range was set higher. On the other hand, the comparative example 2 product obtained by the roasting apparatus not provided with the exhaust port and the drain port was generally inferior to the product of the example, and in particular, the color uniformity and texture were remarkably inferior. . For pistachios, macadamia nuts, and almonds, the same experiment was performed as for cashew nuts, and similar results were obtained.

  The method for producing roasted nuts according to the present invention is suitable for improving the flavor of roasted nuts obtained by producing roasted nuts continuously and without cracking.

1 Roasting room 4 Entrance (roasting room)
5 Exit (roasting room)
6 Conveyor 7 Superheated steam P Cashew nut

Claims (5)

  In the roasting room for roasting nuts, a conveyor for transferring nuts is provided across the entrance and exit of the roasting room, and above the runway above and below the runway for transferring nuts located in the roasting room. A superheated steam roasting device provided with superheated steam spray holes is provided, a drainage port for discharging water derived from the superheated steam is provided at the bottom of the roasting chamber of the roasting device, and A ventilation opening is provided in the upper part of the roasting room, nuts are placed on the runway of the conveyor, and the nuts are continuously carried into the roasting room, and superheated steam from superheated steam injection holes provided above and below the runway. The superheated steam is almost completely removed from the inlet and outlet of the roasting chamber by the action of the ventilation port and the action of discharging excess water derived from the superheated steam from the drain port. In Succoth without preparation of roasted nuts with superheated steam, characterized by roasting the nuts.   The method for producing roasted nuts using superheated steam according to claim 1, wherein the superheated steam is sprayed onto the nuts in a state where the temperature in the roasting chamber is set to 150 to 260 ° C.   The method for producing roasted nuts by superheated steam according to claim 1 or 2, wherein superheated steam having a temperature 20 to 100 ° C higher than the temperature in the roasting chamber is used for jetting superheated steam to the nuts.   The method for producing roasted nuts by superheated steam according to any one of claims 1 to 3, wherein the roasting time for the nuts is 3 to 10 minutes.   The method for producing roasted nuts with superheated steam according to any one of claims 1 to 4, wherein the amount of steam of superheated steam sprayed onto the nuts is 0.80 to 12.0 kg / h.

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