Curing barn for roast duck making and high-temperature oil forcing process thereof

Abstract

The invention discloses a curing barn for making roast ducks and a high-temperature oil forcing technology of the curing barn, and belongs to the technical field of food processing. The curing barn comprises a baking mechanism and a driving mechanism which are matched with each other. An upper drying space, a middle oil forcing space and a lower water locking space are sequentially defined by a curing barn body of the curing mechanism in the vertical direction, and functional assemblies used for achieving specific functions are arranged in the spaces respectively. A hanging rod is arranged on the driving mechanism, and the driving mechanism is configured to be capable of driving the roast duck on the hanging rod to pass through the three spaces in sequence, and the roast duck can rotate. The invention further discloses a process which comprises the following steps: firstly, tightening the skin of the roast duck in a drying space; then moving to an oil forcing space, efficiently forcing subcutaneous fat and crisping the epidermis; and finally, moving to a water locking space, so that the inside is cured and the meat juice is locked. The method solves the problems that traditional roast ducks are greasy, not crisp in skin and unstable in quality, and the roast ducks which are crisp outside and tender inside and are low in fat and healthy can be stably produced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of food processing technology, and in particular to an automatic roasting oven for making roast duck and a high-temperature oil extraction process realized by using the roasting oven. BACKGROUND

[0002] As a world-renowned Chinese cuisine, roast duck is deeply loved by consumers for its unique flavor and crisp texture. Currently, the method for making roast duck on the market mainly relies on traditional hanging or stewing ovens and is operated by experienced chefs. However, the existing background technology has the following technical bottlenecks that have not been effectively solved for a long time in realizing high-quality, standardized and large-scale production: 1. The quality of traditional roast duck, such as the crispness of duck skin, the tenderness of meat, and the uniformity of color, almost entirely depends on the personal experience and sensory judgment of the chef on "fire time". This "artistic" production method leads to differences in products made by different chefs or even the same chef at different times, with large fluctuations in quality, greatly limiting the standardized and chain development of the roast duck industry and making it difficult to achieve stable quality in "thousand stores with the same taste".

[0003] 2. The ideal taste of roast duck "fatty but not greasy" lies in the "oil extraction" process, that is, removing excess fat under the skin. The existing technology mainly allows fat to be passively and slowly melted and rely on gravity to drip through long-time single heat radiation or heat convection. This method is inefficient, and a large amount of liquefied oil is not dripped in time but reabsorbed by the duck skin, or the duck skin is "half-fried and half-fried" under the skin, resulting in an oily taste of the final product and an unrefreshing skin layer, which is contrary to the modern consumer's pursuit of healthy and low-fat diet.

[0004] 3. The traditional oven usually maintains a relatively constant high-temperature dry roasting environment throughout the roasting process. Although this environment is conducive to the crispness of the duck skin, long-time high-temperature roasting also easily leads to a large amount of water loss in the duck meat, causing a taste discontinuity of "crispy skin and dry meat". How to achieve the ultimate crispness of duck skin and maintain the tenderness and juiciness of duck meat in one process flow is a great challenge faced by the existing technology.

[0005] 4. The traditional roasting process takes a long time, and the oven needs to be preheated and maintained at a high temperature for a long time, resulting in huge energy consumption. At the same time, its degree of automation is low, and a large amount of manual intervention is required, limiting the production capacity per unit of time and failing to meet the modern catering industry's requirements for high efficiency and low cost.

[0006] Therefore, there is an urgent need for a new automatic roast duck making device and process that can overcome the above-mentioned defects to realize a leap in the quality of roast duck and modernization of the industry. SUMMARY

[0007] The present application aims to solve the problems of unstable quality, greasy taste and low production efficiency of roasted duck in the prior art, and provides a roasting house for roasting duck with advanced structure and high automation degree and an innovative high-temperature oil pressing process.

[0008] The above technical purpose of the present application is achieved by the following technical scheme: a roasting house for roasting duck, comprising: A roasting mechanism having a roasting house main body defining an internal accommodation space, the roasting house main body defining: An upper drying space, in which a functional assembly for applying continuous hot air to the roasted duck to make its skin tight and dehydrated is arranged; A middle oil pressing space, in which a functional assembly for simultaneously applying infrared heating and pulse hot air to the roasted duck to press out its subcutaneous fat is arranged; and A lower water locking space, in which a functional assembly for low-temperature heating and steam humidification of the roasted duck to make its inside cooked and water-locked is arranged; A driving mechanism, on which a hanging rod for hanging the roasted duck is arranged, and which is configured to drive the hanging rod to pass through the drying space, the oil pressing space and the water locking space in sequence.

[0009] Further, the driving mechanism comprises a lifting driving motor, a lead screw, a guide rod and a lifting hub block; wherein the lifting hub block is threadedly connected with the lead screw and is slidingly connected on the guide rod; the lifting driving motor drives the lead screw to rotate to drive the lifting hub block to move up and down.

[0010] Further, the driving mechanism comprises a rotating top plate and a rotating bottom plate, which are rotatably supported through the top opening and the bottom opening of the roasting house main body respectively; the rotating top plate is provided with a rotating gear disc, and the roasting mechanism is provided with a rotating driving motor and a driving gear, the driving gear is engaged with the rotating gear disc to drive the whole driving mechanism to move in rotation.

[0011] Further, the driving mechanism further comprises an upper partition plate and a lower partition plate arranged on the upper and lower sides of the hanging rod respectively; The upper partition plate and the lower partition plate are penetrated by the lead screw and the guide rod, and are threadedly connected with the lead screw through the threaded holes in the middle parts thereof to move up and down synchronously with the lifting hub block; And the edges of the upper partition plate and the lower partition plate are in sealing sliding fit with the inner wall of the roasting house main body.

[0012] Further, the roasting mechanism further comprises: a dry hot air machine, an oil pressing hot air machine and a steam generator arranged outside the roasting house body; and a grid air outlet, a short-wave infrared heating lamp, a pulse high-speed air outlet and a low-temperature heating plate arranged inside the roasting house body. Wherein: The grid air outlet is arranged in the dry space and communicates with the dry hot air machine. The short-wave infrared heating lamp and the pulse high-speed air outlet are arranged in the oil pressing space, and the pulse high-speed air outlet communicates with the oil pressing hot air machine. The low-temperature heating plate is arranged in the water locking space, and the water locking space communicates with the steam generator.

[0013] The application further provides a high-temperature oil pressing process, which comprises the following steps: a) a drying step: driving the driving mechanism to place the roasted duck in the dry space, starting the functional components of the space to apply continuous hot air, so that the skin is tight and dehydrated; b) an oil pressing step: moving the roasted duck to the oil pressing space, starting the functional components of the space to apply short-wave infrared heating and pulse high-speed hot air at the same time, so that the subcutaneous fat is liquefied and peeled off, and the skin is crispified; c) a water locking step: moving the roasted duck to the water locking space, starting the functional components of the space to apply low-temperature heating and steam humidification, so that the inside is cooked and the juice is locked.

[0014] Further, in at least one of the drying step a), the oil pressing step b) and the water locking step c), the step of rotating the roasted duck on the hanging rod is further included to ensure that the entire skin of the roasted duck is uniformly treated.

[0015] Compared with the prior art, the application has the following beneficial effects: 1. By arranging three independent functional spaces of drying, oil pressing and water locking and corresponding process steps, the skin and internal meat quality of the roasted duck can be treated respectively. The oil pressing process in the middle section aims to remove the fat from the duck skin and form a crisp structure, and the water locking process in the lower section cooks the duck meat in a low-temperature and high-humidity environment, which helps to maintain the moisture of the meat quality, so that the finished product has a crisp skin and juicy internal meat.

[0016] 2. The oil pressing process of the application adopts a mode of short-wave infrared heating and pulse high-speed hot air cooperation. The short-wave infrared is used to preferentially heat the subcutaneous fat layer to liquefy it, and the pulse high-speed hot air applies a physical impact force to the surface of the duck body to promote the liquefied fat to separate from the skin. Compared with the traditional passive oil dripping method relying on gravity, the application provides an active way to remove fat, which can more effectively reduce the residual amount of subcutaneous fat.

[0017] 3、The present application fixes each stage of the roasting process (including processing time, temperature, humidity, air flow, etc.) as parameters that can be accurately repeated by automatic driving mechanism and programmed control of each functional component. This reduces the dependence of production results on the personal experience of the operator and helps to improve the consistency of quality between batches of products.

[0018] 4、The segmented process of the present application optimizes the processing time of each stage, shortens the total length of a single roasting. Especially in the embodiment of forming a moving reaction chamber with upper and lower partition plates, heating and environmental treatment only need to be carried out in a small space around the roasted duck. Compared with heating the entire internal space of the roasting house, this reduces the preheating time of the equipment and the overall energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the roasting house of the present application; Figure 2 is a schematic diagram of the structure of the roasting mechanism of the present application; Figure 3 is a schematic diagram of the driving mechanism of the present application; Figure 4 is Figure 3 is a partial enlarged view of the lifting central block and the components connected around it; Figure 5 is a schematic diagram of the process flow of the present application; Figure 6 is a schematic diagram of the state conversion of the roasted duck in the process of the present application.

[0020] In the figure: 1, roasting mechanism; 2, driving mechanism; 101, roasting house main body; 102, top opening; 103, bottom opening; 104, door; 105, drying hot air fan; 106, grille air outlet; 107, oil pressing hot air fan; 108, short-wave infrared heating lamp; 109, pulsed high-speed air outlet; 110, low-temperature heating plate; 111, steam generator; 112, rotary drive motor; 113, driving gear; 201, lifting drive motor; 202, rotating top plate; 203, rotating toothed disc; 204, rotating bottom plate; 205, lead screw; 206, guide rod; 207, lifting central block; 208, hanging rod; 209, hook; 210, upper partition plate; 211, lower partition plate. DETAILED DESCRIPTION

[0021] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0022] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0024] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0025] See also Figures 1 to 4 A preferred embodiment of a roasting room for making roast duck provided by the present invention includes a roasting mechanism 1 and a driving mechanism 2 that cooperate with each other.

[0026] The roasting mechanism 1 is the main body of the roasting environment. It has a roasting house main body 101 which defines an internal containing space. The roasting house main body 101 is a vertical cylindrical structure, the outer shell is made of stainless steel and filled with ceramic fiber and other thermal insulation materials to ensure good heat insulation effect. The roasting house main body 101 is provided with a door 104 for entering and leaving the roasted duck. One of the cores of the present application is that the internal containing space of the roasting house main body 101 is clearly defined into three functionally different areas in the vertical direction: the upper drying space, the middle oil pressing space and the lower water locking space. Each space is configured with a special function component to achieve a specific process purpose. In the drying space, a grid air inlet 106 is provided in communication with an external drying hot air machine 105 for generating continuous, large-area soft hot air. In the oil pressing space, a plurality of short-wave infrared heating lamps 108 are arranged around the inner wall, and a plurality of pulse-type high-speed air inlets 109 are distributed in a dot matrix manner therebetween, which are in communication with an external oil pressing hot air machine 107. In the water locking space, a plurality of low-temperature heating plates 110 are attached to the inner wall, and the space is connected to an external steam generator 111 through a pipeline.

[0027] The driving mechanism 2 is the core of realizing the automatic movement of the roasted duck. It is at least partially contained in the roasting house main body 101 and is configured to simultaneously realize vertical lifting and overall rotation. Its lifting function is realized by a set of screw rod transmission system, which includes a lifting drive motor 201, a screw rod 205 connected with the motor, a lifting center block 207 threaded with the screw rod, and a guide rod 206 for guiding. A plurality of hanging rods 208 for hanging roasted ducks are radially extended on the lifting center block 207, and hooks 209 are provided on the hanging rods. When the lifting drive motor 201 works, the screw rod 205 rotates, driving the lifting center block 207 and the hanging rods 208 to move up and down along the guide rod 206 stably. Its rotation function is realized by a set of gear transmission system. The overall structure of the driving mechanism 2 is installed on a rotatable platform, which includes a rotating top plate 202 and a rotating bottom plate 204. The rotating top plate 202 is provided with a rotating gear disc 203. The outside of the roasting mechanism 1 is provided with a rotating drive motor 112 and its driving gear 113. When the rotating drive motor 112 works, its driving gear 113 engages the rotating gear disc 203, thereby driving the entire driving mechanism 2 including the lifting system to rotate 360 degrees. The rotating top plate 202 and the rotating bottom plate 204 are rotatably supported through the top opening 102 and the bottom opening 103 of the roasting house main body 101 respectively.

[0028] In a preferred embodiment of the present application, in order to achieve more accurate control of the roasting environment and significantly improve energy efficiency, the driving mechanism 2 further comprises an upper partition plate 210 and a lower partition plate 211 respectively arranged on the upper and lower sides of the hanging rod 208. The introduction of the two partition plates forms a relatively closed "mobile reaction chamber" around the hanging rod 208, which can be lifted and lowered synchronously with the hanging rod 208. This structure aims to solve the problem of heat, airflow and water vapor cross-talk between different functional spaces due to physical connection in traditional fixed partition roasting houses, and overcome the defects of high energy consumption and slow response caused by environmental modification of the entire large space.

[0029] From the perspective of structural implementation, the upper partition plate 210 and the lower partition plate 211 are both penetrated by the lead screw 205 and the guide rod 206. The threaded holes in their respective middle parts are threadedly connected with the lead screw 205, so that when the lifting driving motor 201 drives the lead screw 205 to rotate, they can maintain a fixed relative distance with the lifting center block 207 and perform synchronous lifting movement. At the same time, the edges of the partition plates form a sealed sliding fit with the smooth inner wall of the roasting house main body 101. This fit can be achieved by providing high-temperature-resistant, self-lubricating flexible graphite sealing rings or other sealing elements on the edges of the partition plates, to ensure the isolation effect of the "mobile reaction chamber" from the external space throughout the entire upward and downward movement.

[0030] The "mobile reaction chamber" structure achieves perfect physical isolation of the environment in different process stages. Specifically, when the mobile reaction chamber moves with the duck to the middle oil pressing space, the upper partition plate 210 effectively blocks the downward penetration of low-temperature airflow from the upper drying space, and the lower partition plate 211 completely isolates the upward transpiration of high-concentration water vapor from the lower water locking space. This ensures that the oil pressing space can maintain a pure, undisturbed environment of ultra-high temperature and low humidity, so that the synergistic oil pressing effect of short-wave infrared heating and pulsed hot air is optimized.

[0031] Secondly, this structure greatly improves energy utilization and control response speed. Since heating, humidification and other environmental treatment only needs to be carried out in the local space defined by the two partition plates, which has a much smaller volume than a single functional area, both the preheating time of the equipment and the adjustment speed of the temperature and humidity in the space during process switching are improved by orders of magnitude. This not only significantly reduces the overall energy consumption, but also makes it possible to execute more complex and fine roasting programs that require rapid changes in temperature and humidity.

[0032] Please refer to Figure 5 and Figure 6The present application also provides a high-temperature oil-pressing process for roasted duck. The process moves the roasted duck in sequence through three different functional spaces defined in the roasting chamber main body 101 by means of an automatic driving mechanism 2, and program-controlled functional components in each space, thereby breaking down the complex roasting process into three core steps with clear technical purposes. Throughout the process, the rotating function of the driving mechanism 2 is continuously running to ensure that the entire surface of the roasted duck is evenly processed, thereby obtaining highly consistent finished products.

[0033] a) drying step: The pre-processed duck blanks are hung on the hanging rods 208 of the driving mechanism 2. After starting the program, the driving mechanism 2 first moves and positions the roasted duck into the upper drying space. Then, the functional components of this space are activated, and the drying hot air blower 105 set outside the roasting chamber main body 101 starts working, delivering continuous hot air with a temperature setting of 80-100°C into the space through the grid air inlet 106 set on the inner wall of the drying space. This step uses dry hot air with a certain flow rate to force convection heat transfer on the surface of the duck blanks, not for roasting, but for quickly and efficiently removing excess moisture inside and outside the surface of the duck blanks. In this process, first, the removal of moisture causes the collagen in the duck skin to shrink and the tissue structure to become more compact, thereby forming a thin and tough physical shell; second, this tough shell improves the mechanical strength of the surface skin, effectively preventing the surface skin from cracking due to the instantaneous and violent vaporization of subcutaneous moisture and the resulting high steam pressure in the subsequent middle oil-pressing space, laying the foundation for the formation of a complete and beautiful crispy surface skin.

[0034] b) oil-pressing step: After the drying step, the driving mechanism 2 moves the duck skin that has been tightened to the middle oil pressing space. After the functional components in the space are activated, firstly, the multiple short-wave infrared heating lamps 108 arranged around the inner wall of the oil pressing space are started. The emitted short-wave infrared rays have strong penetrating ability and can penetrate through the duck skin and be preferentially and efficiently absorbed by the subcutaneous fat layer, so as to realize "targeted heating" of the deep fat and make it liquefy rapidly and in large quantities in a short time. At the same time, the oil pressing hot air blower 107 arranged outside delivers high-temperature and high-pressure gas to the pulse-type high-speed air port 109 arranged on the inner wall of the oil pressing space, and through the high-frequency on-off of the electromagnetic valve, the pulse-type high-speed hot air with a temperature of about 250-280°C and high kinetic energy is formed. The working principle of the hot air is not simply heating, but applying an intermittent and high-intensity physical impact force to the surface of the duck. The impact force can forcibly and rapidly "blow off" or "peel off" the fat that has been deeply liquefied by the infrared rays from the pores and tissue gaps of the duck body. The synergistic effect of "internal melting first and external peeling later" provides an active and efficient way of degreasing, and the degreasing process is faster and more complete compared with the traditional passive way relying on gravity dripping. At the same time of maximizing the removal of subcutaneous fat and reducing the greasy feeling of the finished product, the proteins and sugars in the duck skin after degreasing are directly exposed to ultra-high temperature and rapidly undergo Maillard reaction and caramelization reaction, thereby forming a golden yellow, loose and crispy layer.

[0035] c) Water locking step: After the oil pressing and crisping, the driving mechanism 2 continues to move the roasted duck downward to the lower water locking space. This step aims to solve the technical problem of "crispy skin and tough meat" in the traditional dry roasting process. After the functional components in the space are activated, the low-temperature heating plate 110 attached to the inner wall provides a gentle heat of about 120-150°C, which is no longer high-temperature roasting, but a "braising" way that allows the heat to penetrate to the deepest part of the duck meat and make it fully cooked without overcooking. At the same time, the steam generator 111 outside injects water vapor into the space to maintain a high-humidity environment. By increasing the steam pressure around the roasted duck, it is close to or higher than the saturated steam pressure of the water in the duck meat, thereby greatly reducing the pressure difference between them and effectively inhibiting the further evaporation of the juice inside the duck meat. This step maintains the crispness of the outer duck skin while performing a "water replenishing" and "meat resting" treatment on the inner duck meat, allowing the muscle fibers that have been tightened due to high temperature to relax, and finally achieving the ideal taste of meaty, tender and juicy, perfectly realizing the quality goal of "crispy outside and tender inside".

[0036] In summary, the present application converts the traditional, experience-dependent roast duck making process into an automated, precisely controllable industrial production process through its unique roasting room structure and three-stage process.

[0037] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A roast duck production room, characterized in that: include: The baking mechanism (1) comprises a baking room body (101) defining an internal accommodation space, wherein the baking room body (101) defines in a vertical direction: The upper drying space is equipped with a functional component for applying continuous hot air to the roast duck to tighten and dehydrate its skin; The fat-expelling space in the middle is equipped with a functional component for simultaneously applying infrared heating and pulsed hot air to the roast duck to expel its subcutaneous fat; and The water-locking space at the bottom contains functional components for low-temperature heating and steam humidification of the roast duck to mature the duck and lock in moisture. A driving mechanism (2) is provided with a hanging rod (208) for hanging the roast duck, and is configured to drive the hanging rod (208) to pass through the drying space, the oil-forcing space, and the water-locking space in sequence.

2. The curing barn according to claim 1, wherein: The driving mechanism (2) comprises a lifting drive motor (201), a screw rod (205), a guide rod (206) and a lifting hub block (207); wherein the lifting hub block (207) is threadedly engaged with the screw rod (205) and is slidably connected to the guide rod (206); the lifting drive motor (201) drives the screw rod (205) to rotate, thereby driving the lifting hub block (207) to perform lifting motion.

3. The curing barn according to claim 1, wherein: The driving mechanism (2) comprises a rotating top plate (202) and a rotating bottom plate (204), wherein the rotating top plate (202) and the rotating bottom plate (204) are rotatably supported through the top opening (102) and the bottom opening (103) of the baking room body (101), respectively; a rotating toothed disc (203) is provided on the rotating top plate (202), and a rotating driving motor (112) and a driving gear (113) thereof are provided on the baking mechanism (1); the driving gear (113) is engaged with the rotating toothed disc (203) to drive the entire driving mechanism (2) to perform a rotating motion.

4. The curing barn according to claim 1, wherein: The driving mechanism (2) further comprises an upper partition plate (210) and a lower partition plate (211) respectively arranged on the upper and lower sides of the hanging rod (208); The upper partition plate (210) and the lower partition plate (211) are both penetrated by the screw rod (205) and the guide rod (206), and are threadedly engaged with the screw rod (205) through the threaded holes in their respective middle portions to perform lifting and lowering motion synchronously with the lifting hub block (207); Furthermore, the edges of the upper partition plate (210) and the lower partition plate (211) form a sealed sliding fit with the inner wall of the baking room body (101).

5. The curing barn according to claim 1, wherein: The baking mechanism (1) further comprises: a drying hot air blower (105), an oil-forcing hot air blower (107), and a steam generator (111) arranged outside the baking room body (101); and a grille air vent (106), a short-wave infrared heating lamp (108), a pulse-type high-speed air vent (109), and a low-temperature heating plate (110) arranged inside the baking room body (101); in: The grille air outlet (106) is arranged in the drying space and is in communication with the drying hot air blower (105); The short-wave infrared heating lamp (108) and the pulse-type high-speed air port (109) are arranged in the oil-forcing space, and the pulse-type high-speed air port (109) is connected to the oil-forcing hot air blower (107); The low-temperature heating plate (110) is arranged in the water-locking space, and the water-locking space is in communication with the steam generator (111).

6. A high-temperature oil-forcing process using the baking room according to any one of claims 1 to 5, characterized in that: The following steps are involved: a) Drying step: driving the driving mechanism (2) to place the roast duck in a drying space, and activating the functional components of the space to apply continuous hot air to tighten and dehydrate the duck's skin; b) Fat extraction step: The roast duck is moved into the fat extraction chamber, where the functional components are activated to simultaneously apply short-wave infrared heating and pulsed high-speed hot air to liquefy and remove the subcutaneous fat while crisping the skin. c) Moisture-locking step: The roast duck is moved into the moisture-locking space, and the functional components of the space are activated to apply low-temperature heating and steam humidification to ripen the interior and lock in the meat juice.

7. The high-temperature oil-forcing process according to claim 6, characterized in that: In at least one of the drying step a), the oil-forcing step b) and the moisture-locking step c), the step of rotating the roast duck on the hanging rod (208) is also included to ensure that the entire skin of the roast duck is evenly processed.

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