Multi-zone sampling ultrasonic reactor and grapefruit debitterizing and dairy product preparation method

Abstract

The invention discloses a multi-zone sampling ultrasonic reactor and a grapefruit debitterizing and dairy product preparation method. The reactor comprises a main reaction tank, a hollow rotating main shaft, a rotating paraboloid focusing reflector, a spiral mixing strengthening area and an independent annular detection cavity. An optical detection system in which a fixed light source is matched with a rotary light receiving end is adopted, and selective sampling of different space areas is realized by regulating and controlling the rotating speed of a main shaft (80rpm in a P1 area and 180rpm in a P2 area). In the application of naringin enzyme method debitterizing, a four-stage step-by-step control strategy based on double-region real-time online detection is adopted. The preparation process of the functional grapefruit dairy product comprises the following steps: pretreating milk (adding 0.3% of pectin and 0.2% of carrageenan to compound a stabilizer and 8% of white granulated sugar, melting the gum at 75 DEG C for 10 minutes, and then performing pre-pasteurization at 85 DEG C for 15 seconds); compounding the debittered grapefruit extracting solution with milk according to a mass ratio, and adjusting the pH value to 6.50 + / -0.05 by using citric acid; the fat globules are crushed to Dlt through two-stage high-pressure homogenization; 1.0 [mu] m; uHT ultrahigh temperature instantaneous sterilization (137 DEG C / 4 seconds) realizes commercial sterility.

Description

Technical Field

[0001] This invention relates to the field of food processing equipment and technology, specifically to a multi-region sampling ultrasonic reactor and its application in the debittering treatment of grapefruit, and more specifically, to a rotating focusing ultrasonic reactor with multi-region selective sampling function, a method for debittering grapefruit peel using the reactor via naringinase, and a method for preparing functional grapefruit dairy products. Background Technology

[0002] Grapefruit is rich in nutrients such as vitamin C, flavonoids, and dietary fiber, and has various physiological functions such as anti-oxidation, lowering blood lipids, and enhancing immunity. However, grapefruit fruit and peel contain a large amount of naringin, which has a strong bitter taste.

[0003] The debittering treatment of naringin mainly employs enzymatic conversion technology. This method utilizes α-rhamnosidase, naringinase, and other enzymes to specifically hydrolyze the rhamnose-glucosidic bond of naringin, converting naringin into low-bitter or non-bitter naringenin and further products such as naringenin aglycones. Enzymatic conversion has advantages such as mild reaction conditions, high selectivity, and preservation of nutrients, making it the most promising debittering technology route currently available.

[0004] However, traditional enzymatic debittering reactions have the following technical challenges: Slow reaction rate: Naringin has a large molecular weight (580.5 Da) and poor water solubility, resulting in low enzyme-substrate contact efficiency. The enzyme-catalyzed reaction rate is slow in conventional stirred reactors, and industrial processing requires 4-8 hours or even longer, resulting in low production efficiency. Mass transfer limitations are severe: Mass transfer dead zones and concentration gradients exist in large-scale reactors, and the uneven distribution of substrates, enzymes and products leads to incomplete or excessive reactions in local areas, affecting the stability of product quality. Poor reaction uniformity: There is a lack of effective spatial distribution monitoring methods, making it impossible to assess the conversion rate differences at different locations within the reactor in real time, and making it difficult to optimize mixing parameters and reaction conditions; Endpoint control is difficult: Traditional offline sampling analysis has a time lag (usually requiring 30-60 minutes), making it impossible to achieve accurate real-time endpoint determination, which can easily lead to under-reaction (residual bitterness) or over-reaction (flavor loss, increased energy consumption). Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rotating focusing ultrasonic reactor with multi-region selective sampling function, as well as a method for preparing functional grapefruit dairy products by using the reactor for enzymatic debittering of naringin, so as to solve the technical problems of slow reaction rate, severe mass transfer limitation, poor reaction uniformity and difficulty in endpoint control of traditional enzymatic debittering reaction, and achieve efficient, uniform and controllable treatment of naringin debittering reaction.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: This invention provides a rotating focusing ultrasonic reactor with multi-region selective sampling function, comprising: The main reaction vessel adopts a vertical cylindrical structure, and multiple ultrasonic transducers are evenly arranged around the circumference of the vessel wall. The emission direction of the ultrasonic transducers is designed to be tilted upward to ensure that the ultrasonic waves can effectively enter the interior of the rotating parabolic focusing reflector. A hollow rotating main shaft passes vertically through the top of the main reaction tank and is connected to the drive device via a coupling. The hollow rotating main shaft has an enlarged diameter section and an inner cavity with at least one channel for transmitting optical signals and transporting sampling liquid. The rotating parabolic focusing reflector is fixed to the hollow rotating main shaft by a support arm and rotates synchronously with it. The rotating parabolic focusing reflector has a parabolic rotating body structure with an opening facing downwards. Its inner surface is an ultrasonic reflecting surface. The ultrasonic waves emitted by the ultrasonic transducer enter from the opening below the rotating parabolic focusing reflector, are reflected on the inner surface of the parabola and converge at the focal region to form a high-intensity ultrasonic field. An independent annular detection chamber is fitted around the expanded section of the hollow rotating main shaft and rigidly fixed by threads or welding. It rotates synchronously with the hollow rotating main shaft. The independent annular detection chamber is equipped with a sampling port, which is connected to an external sampling system through the inner cavity channel of the hollow rotating main shaft. A filter screen is installed inside the sampling port to prevent solid particles or air bubbles from entering. The online optical inspection system includes a light source fixed to the inner wall of the main reaction vessel, a light-transmitting window at the light source end set on the outer wall of an independent annular inspection cavity, a light-receiving window at the light-receiving end set on the expanded section of the hollow rotating main shaft and radially corresponding to the light-transmitting window at the light source end, and an optical transmission component that transmits the light signal to an external optical inspection device through the inner cavity channel of the hollow rotating main shaft; when the hollow rotating main shaft rotates to a specific angle so that the light-receiving window at the light-receiving end is aligned with the light source, the light signal can be effectively transmitted and collected by the optical inspection device; The multi-region selective sampling system changes the flow field distribution within the reactor by adjusting the reactor operating parameters, driving liquids from different spatial regions to the independent annular detection chamber for online detection, thereby achieving conversion rate monitoring and reaction uniformity assessment at multiple spatial distributions within the reactor.

[0007] Furthermore, the hollow rotating spindle has two independent channels: a central optical fiber channel and an eccentric sampling / cleaning channel. The central optical fiber channel is located at the axis of the hollow rotating spindle and extends continuously from the upper optical rotary joint to the expansion section, serving to accommodate the quartz optical fiber. The eccentric sampling / cleaning channel is spirally arranged along the inner wall of the hollow rotating spindle and extends continuously from the upper sampling / cleaning rotary joint to the sampling port of the independent annular detection cavity at the expansion section. A rotary joint is installed at the upper end of the hollow rotating spindle, and the eccentric sampling / cleaning channel is connected to a three-way electromagnetic switching valve group through the rotary joint. One channel of this valve group is connected to a vacuum pump system for negative pressure sampling, and the other channel is connected to a cleaning fluid supply system for cleaning water supply. The automatic switching between sampling mode and cleaning mode is achieved through a control system.

[0008] Furthermore, it also includes a spiral mixing enhancement zone, which is located directly below the rotating parabolic focusing reflector and coaxially mounted with the hollow rotating main shaft. This zone includes a double-helix guide tube and a built-in double-helix blade assembly. The double-helix guide tube is a cylindrical body with its upper opening connecting to the opening of the rotating parabolic focusing reflector to form a continuous flow channel, and its lower opening communicating with the main reaction vessel's main body space. The double-helix blade assembly includes left-handed and right-handed spiral blades, arranged alternately along the axial direction, with uniformly distributed through-holes on the blades to enhance the mixing effect and promote ultrasonic wave propagation.

[0009] Furthermore, four ultrasonic transducers are evenly arranged around the circumference of the tank wall, and the installation height is located about 100-200mm below the opening of the rotating parabolic focusing reflector. The emission direction is designed to be tilted upwards with an elevation angle of about 15-20° to ensure that the ultrasonic waves can effectively irradiate the inner surface of the parabolic surface and achieve focused reflection.

[0010] Furthermore, the multi-region selective sampling system achieves selective sampling of at least two different spatial regions within the reactor by adjusting the rotational speed of the hollow rotating spindle, the ultrasonic frequency, the ultrasonic power, and the pre-rotation time. Through systematic experiments and fluid dynamics simulations, the flow field control parameters corresponding to different spatial regions are determined, enabling the liquid in the target region to be driven to the sampling port of the independent annular detection chamber and drawn into the detection chamber through negative pressure under the set parameters.

[0011] Furthermore, the at least two different spatial regions include: P1 region (central fast response zone): The central columnar region adjacent to the hollow rotating spindle, containing the central part of the entrance to the parabolic internal ultrasonic focusing core response zone and the spiral hybrid enhancement zone. This region has the highest ultrasonic intensity and the fastest response rate. The sampling conditions are: hollow rotating spindle speed 60-100 rpm, ultrasonic frequency off or low power, and short pre-rotation time. P2 region (peripheral mixing representative area): The outer annular area 200-350mm from the hollow rotating main shaft, including the periphery of the spiral mixing zone, the near-wall flow boundary layer, and the main reaction volume in the lower part of the tank. This region accounts for about 70% of the total reactor volume and is representative of the whole. The sampling conditions are: hollow rotating main shaft speed of 150-200rpm, high frequency ultrasonic frequency, high ultrasonic power, and long pre-rotation time.

[0012] The present invention also provides a method for debittering naringin by using the above-mentioned rotating focusing ultrasonic reactor, comprising the following steps: (1) Preparation of grapefruit extract and initialization of reaction system: Grapefruit extract containing naringin was put into the main reaction tank. The pH value of the reaction solution was adjusted to 7.0-7.5 using an alkaline regulator. The tank jacket circulating heating system was started to raise the temperature of the reaction solution to 45℃ and stabilize it. After adding glycosidase, the stirring and ultrasonic system of the rotating focusing ultrasonic reactor were started. (2) Staged reaction process control: During the reaction, different spatial regions are sampled by a multi-region selective sampling system, and the conversion rate of naringin is monitored in real time by an online optical detection system; at least two different spatial regions are sampled and detected, and the average conversion rate, conversion rate difference and uniformity coefficient of each region are calculated to evaluate the reaction uniformity; (3) Precise endpoint control and enzyme inactivation treatment: Adjust reaction parameters in real time according to online detection results. When the online dual-region detection shows that the conversion rate reaches the target value and the uniformity is good, stop the ultrasonic system immediately, and quickly heat up to 85°C through the tank jacket and keep it for 5 minutes to completely inactivate the enzyme.

[0013] Furthermore, the reaction process in step (2) employs a staged control strategy, including: Mild start-up period: Mild reaction conditions are adopted, with the hollow rotating spindle speed at 60 rpm, ultrasonic frequency at 20 kHz, and ultrasonic power at 300 W. The P1 area is sampled and detected at regular intervals. The dual-area scanning program is started at 15 minutes. The reaction uniformity is evaluated and the parameters are adjusted based on the difference in conversion rate between the two areas. Rapid response phase: The hollow rotating spindle rotates at 100 rpm, the ultrasonic frequency is 28 kHz, the ultrasonic power is 200 W, and a dual-region scan is performed every 10 minutes. When the conversion rate of the P2 region reaches about 45%, the next stage is triggered. Precision control period: The hollow rotating spindle speed is 150 rpm, the ultrasonic frequency is 40 kHz, the ultrasonic power is 100 W, and a dual-region scan is performed every 5 minutes. When the conversion rate of the P2 region reaches 55-58% and the difference between the conversion rates of the two regions is reduced to within 5%, the enzyme inactivation program is automatically triggered. Rapid enzyme inactivation phase: Stop the ultrasonic system, increase the speed of the hollow rotating spindle to 200 rpm, rapidly heat to 85°C through the tank jacket and maintain for 5 minutes, then rapidly cool to 40°C.

[0014] This invention also provides a method for preparing a functional grapefruit dairy product. The method involves enzymatically debittering grapefruit extract using the above-mentioned method, then compounding the treated grapefruit extract with a dairy product base at a mass ratio of 5:95 to 10:90, preferably 7:93. After two-stage high-pressure homogenization, the mixture is sterilized by UHT ultra-high temperature instantaneous sterilization and aseptically filled to obtain the functional grapefruit dairy product. The dairy product base is selected from one or more of whole milk, skim milk, partially skimmed milk, reconstituted milk, or soy milk.

[0015] Compared with the prior art, the present invention has the following beneficial effects: Significantly improved reaction efficiency: The use of a rotating parabolic focusing reflector concentrates ultrasound waves into the focal region, forming a high-intensity ultrasound field. The ultrasound energy is concentrated on the core reaction zone, significantly enhancing the contact frequency and mass transfer efficiency between the enzyme and the substrate.

[0016] Significantly improved reaction uniformity: Through the synergistic effect of the rotating parabolic focusing reflector and the spiral mixing reinforcement zone, the ultrasonic focusing reaction and reinforcement mixing are organically combined to form a complete three-dimensional flow cycle; dual-region selective sampling detection shows that the conversion rate difference between the central region and the peripheral region is controllable, and the uniformity is greatly improved.

[0017] Achieving multi-region selective sampling and real-time monitoring: Through an independent annular detection chamber and a multi-region selective sampling system, selective sampling of different spatial regions within the reactor can be achieved; combined with an online optical detection system, the conversion rate of naringin can be monitored in real time, and the uniformity of the reaction can be evaluated, overcoming the shortcomings of time lag and poor spatial representativeness of traditional offline sampling and analysis.

[0018] Precise and reliable endpoint control: Based on a phased control strategy using real-time online detection, reaction parameters are dynamically adjusted according to the conversion rate in both regions. When the conversion rate reaches the target value and the uniformity is good, the enzyme inactivation program is triggered immediately, avoiding insufficient or excessive reaction and ensuring stable product quality. The deviation between online optical detection results and offline HPLC detection is less than 3%, verifying the accuracy and reliability of the detection system. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of the overall structure of the rotating focusing ultrasonic reactor of the present invention, showing the spatial arrangement of the main components and the liquid flow path.

[0020] Figure 2This is a partially enlarged cross-sectional view of the independent annular detection cavity 60 and its supporting optical detection system, which highlights the cooperation between the fixed light source and the rotating light-collecting end.

[0021] Figure 3 This is a complete workflow diagram of the multi-region selective sampling system of the present invention, showing the four main steps and their sub-steps from flow field control, negative pressure sampling, spectral detection to evacuation and cleaning.

[0022] Numbering on the map: 10 Main reaction vessel; 20 Ultrasonic transducer; 30 Hollow rotating spindle; 40 Rotating parabolic focusing reflector; 50 Double helix guide tube; 51 Double helix blade assembly; 60 Independent annular detection cavity; 70 Fixed light source; 80 Optical detection device. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0024] This embodiment provides a rotating focusing ultrasonic reactor with multi-region selective sampling function, and a method for preparing functional grapefruit dairy products using the rotating focusing ultrasonic reactor for debittering treatment with naringinase. The rotating focusing ultrasonic reactor is equipped with an independent annular detection cavity 60 and an online optical detection system, enabling selective sampling and real-time conversion rate monitoring of different spatial regions within the reactor by adjusting operating parameters.

[0025] I. Rotary Focusing Ultrasonic Reactor.

[0026] The rotary focusing ultrasonic reactor of this embodiment includes a main reaction vessel 10, a hollow rotating main shaft 30, a rotating parabolic focusing reflector 40, a spiral mixing reinforcement zone, an independent annular detection cavity 60, and a multi-region selective sampling system. The hollow rotating main shaft 30 vertically passes through the top of the main reaction vessel 10 and is connected to a servo motor; the rotating parabolic focusing reflector 40 and the spiral mixing reinforcement zone are sequentially fixed to the hollow rotating main shaft 30 and rotate synchronously with it; the independent annular detection cavity 60 is fitted into the expanded diameter section of the hollow rotating main shaft 30 and achieves multi-region selective sampling and online detection through its built-in channels.

[0027] 1.1 Main Reactor 10: The main reaction vessel 10 adopts a vertical cylindrical structure with an effective volume of 603L, an inner diameter of 800mm, and a height of 1200mm. The vessel body is made of 316L stainless steel with a mirror-polished inner surface. The side wall of the vessel body is equipped with a jacket layer for circulating temperature control medium to achieve precise control of the reaction temperature.

[0028] The top of the tank is equipped with a flange-type detachable tank cover. A 120mm diameter hollow rotating spindle 30 is opened in the center of the tank cover for installing the hollow rotating spindle 30 and cooperating with the mechanical seal device.

[0029] Four ultrasonic transducers 20 are evenly arranged around the circumference of the tank wall, and are installed at a height of about 100-200 mm below the opening of the rotating parabolic focusing reflector 40. The emission direction of the ultrasonic transducers 20 is designed to be slightly tilted upward (elevation angle of about 15-20°) to ensure that the ultrasonic waves enter from the opening below the rotating parabolic focusing reflector 40, effectively irradiate the inner surface (concave surface) of the parabola, and achieve focusing and reflection.

[0030] 1.2 Hollow Rotary Spindle 30: The hollow rotating main shaft 30 is the core transmission and integrated component of this rotating focusing ultrasonic reactor, undertaking multiple functions such as power transmission, optical signal transmission, and negative pressure sampling.

[0031] The hollow rotating spindle 30 is a hollow cylindrical structure with dimensions such as an outer diameter of 50mm, an inner diameter of 20mm, a wall thickness of 15mm, and a total length of 1200mm. The upper end of the hollow rotating spindle 30 is connected to a servo motor via a coupling, and this servo motor is equipped with an encoder for precise speed control. The lower end of the hollow rotating spindle 30 is a free end that extends into the main reaction vessel 10, approximately 300mm from the bottom of the vessel.

[0032] A double-end mechanical seal device is installed at the through hole of the hollow rotating spindle 30 passing through the tank cover to ensure that the reaction liquid inside the tank does not leak during the rotation of the hollow rotating spindle 30, while maintaining a sealed environment inside the tank.

[0033] The hollow rotating spindle 30 has an enlarged section at an appropriate distance from the upper end, for example, 650-700mm from the upper end. The outer diameter of this enlarged section is increased to 60mm, and the total length of the enlarged section is 80mm. A 15mm long tapered transition section with a taper of 1:3 is provided at both the upper and lower ends of the enlarged section to ensure a smooth transition of resistance when liquid flows through it. This enlarged section is used to install the independent annular detection chamber 60 (see Section 1.5 for details).

[0034] Two rotary joints are installed on the upper end of the hollow rotary spindle 30 (above the can lid), for optical signal transmission and negative pressure sampling, respectively: (1) Optical rotary joint: Located at the center of the hollow rotating spindle 30, it is a single-channel optical rotary joint that accommodates a quartz optical fiber with a core diameter of 3mm. The rotary joint adopts an optical alignment structure to ensure that the optical signal transmission loss is less than 5% during rotation.

[0035] (2) Sampling / Cleaning Rotary Joint: Located at the 30° eccentric position of the hollow rotating spindle, with an inner diameter of 8mm. This rotary joint uses silicon carbide dynamic and static ring seals to ensure the airtightness of the system. The stationary end of the rotary joint is connected to a three-way electromagnetic switching valve group: one channel is connected to the vacuum pump system for negative pressure sampling, and the other channel is connected to the pure water supply system for cleaning water supply. The automatic switching between sampling mode and cleaning mode is achieved through PLC control.

[0036] The hollow rotating spindle 30 has two independent channels inside its cavity: (1) Central fiber optic channel: Located at the center of the hollow rotating spindle 30, with a channel diameter of 5mm, it extends continuously from the upper optical rotary joint of the hollow rotating spindle 30 to the expanded diameter section of the hollow rotating spindle 30. The quartz fiber enters from the optical rotary joint, passes through the central channel, and reaches the optical window of the independent annular detection cavity 60 at the expanded diameter section.

[0037] (2) Eccentric sampling / cleaning channel: arranged spirally along the inner wall of the hollow rotating main shaft 30, with an inner diameter of 8mm. This channel extends continuously from the sampling / cleaning rotary joint at the upper end of the hollow rotating main shaft 30 to the sampling port of the independent annular detection chamber 60 at the expansion section. The spiral arrangement can reduce the generation of eddies and bubbles in the liquid during negative pressure suction, while ensuring uniform delivery of the cleaning fluid in cleaning mode.

[0038] 1.3 Rotating parabolic focusing reflector 40: The rotating parabolic focusing reflector 40 is rigidly connected to the hollow rotating main shaft 30 via six support arms. The support arms have a streamlined cross-section to reduce rotational resistance. The rotating parabolic focusing reflector 40 is installed 400-600mm from the top of the hollow rotating main shaft 30 (adjustable within this range). When the reaction liquid loading is 400L, the rotating parabolic focusing reflector 40 is located 100-300mm below the liquid surface.

[0039] The rotating parabolic focusing reflector 40 has a parabolic rotating body structure, shaped like an inverted bowl with its opening facing downwards. Dimensions include a maximum outer diameter of 300mm, a height of 200mm, a wall thickness of 3mm, and is made of 316L stainless steel. The parabolic radius of curvature is 150mm, the focal length is 75mm, and the opening angle is 60°.

[0040] The parabolic opening faces downwards. The top (sealed end) of the parabolic surface is a circular sealing plate with a diameter of approximately 50 mm. The center of the sealing plate is connected to the hollow rotating main shaft 30 via a support arm. The edge of the parabolic opening is approximately 50-80 mm away from the upper surface of the expanded section of the hollow rotating main shaft 30, ensuring that the liquid can freely enter and exit the reaction zone and form a continuous flow channel with the spiral mixing enhancement zone below.

[0041] The inner surface (concave surface) of the rotating parabolic focusing reflector 40 is electrolytically polished, with a surface roughness Ra≤0.2μm, and an ultrasonic reflectivity greater than 95% in the frequency range of 20-40kHz.

[0042] Working principle of focused ultrasound: Ultrasonic emission: Four ultrasonic transducers 20 on the tank wall are located below the opening of the rotating parabolic focusing reflector 40. The emitted ultrasonic waves propagate slightly upward (elevation angle 15-20°) and pass through the liquid medium obliquely upward.

[0043] Ultrasonic Reception: Ultrasonic waves propagate upwards at a certain elevation angle from below the rotating parabolic focusing reflector 40, entering the internal space of the rotating parabolic focusing reflector 40 through the parabolic opening (below), and effectively irradiating the inner surface (concave surface) of the parabolic surface. Focusing Reflection: The ultrasonic waves are reflected on the inner surface of the parabolic surface. According to the geometric characteristics of the parabolic surface, all parallel incident ultrasonic beams converge to the same focusing area after reflection. This focusing area is located downwards from the top (sealed end) of the parabolic surface, for example, approximately 125-175 mm upwards from the edge of the parabolic opening, corresponding to the area directly below the expanded diameter section of the hollow rotating spindle 30.

[0044] High-intensity ultrasonic field formation: Ultrasonic waves emitted by four ultrasonic transducers 20 are reflected by a parabolic surface and superimposed in the focal region to form a high-intensity ultrasonic field. At the same time, the focal region is directly opposite the entrance of the helical mixing enhancement zone, which is the core reaction zone with the fastest enzyme-catalyzed reaction rate.

[0045] Liquid flow path: Under the combined action of the hollow rotating main shaft 30, ultrasonic flow and helical blades, the reaction liquid enters the internal space of the rotating parabolic focusing reflector 40 from the lower opening of the parabolic surface, flows upward through the ultrasonic focusing high-intensity reaction zone, and then flows downward out of the opening into the helical mixing enhancement zone, forming a continuous circulation flow.

[0046] 1.4 Spiral Hybrid Reinforcement Zone: The spiral mixing enhancement zone is located directly below the rotating parabolic focusing reflector 40 and is coaxially mounted with the hollow rotating main shaft 30. This zone consists of a double-helix guide tube 50 and an internal double-helix blade assembly 51, which receives the reaction liquid flowing out from the parabolic opening and performs enhanced mixing treatment.

[0047] The double-helix flow guide tube 50 is a cylindrical body with dimensions such as an outer diameter of 250 mm, a height of 300 mm, and a wall thickness of 3 mm, made of 316L stainless steel. The upper opening of the double-helix flow guide tube 50 spatially aligns with the opening of the parabolic rotating reflector 40, forming a continuous flow channel. The double-helix flow guide tube 50 is fixed to the hollow rotating main shaft 30 via a connecting flange or support arm, and rotates synchronously with the hollow rotating main shaft 30. The lower end of the double-helix flow guide tube 50 has an open structure, communicating with the main body space of the main reaction tank 10.

[0048] The double-helix guide tube 50 is internally equipped with a set of double-helix blades 51, including left-handed and right-handed helix blades, which are arranged alternately along the axial direction. The structural parameters of a single helix blade are as follows: width 30mm, thickness 3mm, pitch 100mm, helix angle 45°, and the outer edge of the blade maintains a 5mm gap with the inner wall of the double-helix guide tube 50 to prevent wear and jamming.

[0049] Each helical blade has 20 evenly spaced 10mm diameter holes, with an opening rate of about 40%. The purpose of the opening design is to: (1) allow the liquid to flow and exchange between the axial and radial directions, enhancing the mixing effect; (2) reduce the blade rotation resistance; and (3) promote the propagation of ultrasonic waves in the axial direction.

[0050] The upper central region of the helical mixing enhancement zone (directly below the expanded section of the hollow rotating main shaft 30) receives ultrasonic focusing energy from the parabolic rotating parabolic focusing reflector 40. This region has the highest ultrasonic intensity and the fastest enzyme-catalyzed reaction rate. After undergoing high-intensity ultrasonic action in this region, the liquid flows downwards driven by the helical blades and mixes with the liquid at the bottom of the rotating focusing ultrasonic reactor. It then re-enters the parabolic rotating parabolic focusing reflector 40 through circumferential circulation, forming a complete three-dimensional flow cycle.

[0051] 1.5 Independent annular detection cavity 60 and multi-region selective sampling system: This rotating focusing ultrasonic reactor enables selective sampling and real-time online detection of different internal spatial regions, used to monitor the enzymatic debittering conversion rate of naringin in the reaction solution and assess reaction uniformity. The system includes an independent annular detection chamber 60, a fixed light source 70, a rotating optical detection device 80 for collecting light, and a negative pressure sampling system.

[0052] The independent annular detection cavity 60 is fitted around the expanded section of the hollow rotating spindle 30, concentric with the hollow rotating spindle 30 and rigidly fixed by threads or welding, and rotates synchronously with the hollow rotating spindle 30.

[0053] The independent annular detection cavity 60 has an annular structure with a cavity height of 50mm, an outer diameter of 120mm, and an inner diameter of 60mm (which matches the outer diameter of the expanded section of the hollow rotating main shaft 30). The effective detection volume of the annular space is approximately 150mL.

[0054] The independent annular detection chamber 60 is made of 316L stainless steel, with its inner surface electropolished to a surface roughness Ra≤0.2μm, preventing sample adhesion from affecting detection accuracy. The independent annular detection chamber 60 consists of three parts: a chamber body section, an upper end cover, and a lower end cover. The upper and lower end covers are connected to the chamber body section via flanges and sealed with O-rings, ensuring spatial isolation between the independent annular detection chamber 60 and the main body of the rotating focusing ultrasonic reactor.

[0055] A sampling hole with a diameter of 6mm is opened at the center of the upper end cover of the independent annular detection chamber 60. A 40-mesh stainless steel filter screen is installed inside the sampling hole to prevent solid particles or air bubbles from entering the independent annular detection chamber 60. The sampling hole is connected to the eccentric negative pressure channel inside the hollow rotating spindle 30 through an internal threaded joint. The lower end cover of the independent annular detection chamber 60 is equipped with a discharge valve for returning the sample to the rotary focusing ultrasonic reactor or for cleaning after the detection is completed.

[0056] An optical window is formed on the outer wall of the independent annular detection cavity 60 at its center height (25mm from the upper end cover) to mount a sapphire window as the light source incident end. Correspondingly, an optical window is formed on the equal-diameter section of the expanded diameter section of the hollow rotating spindle 30 at a position radially opposite to the optical window on the outer wall of the independent annular detection cavity 60 to mount a sapphire window as the light signal collecting end. The line connecting the centers of the two optical windows constitutes the detection optical path.

[0057] Light source end structure: The ultraviolet LED light source module is fixedly mounted on a bracket on the inner wall of the main reaction vessel 10. The bracket position is precisely adjusted so that the light source module is in close contact with the outer side of the optical window on the outer wall of the independent annular detection cavity 60. The light source module uses a deep ultraviolet LED with a peak wavelength of 280nm and a rated power of 3W. It is equipped with a collimating lens (focal length 20mm, numerical aperture 0.3) to focus the light beam into a parallel beam with a diameter of approximately 8mm, which passes through the sapphire window on the outer wall of the independent annular detection cavity 60 and enters the cavity.

[0058] The optical window on the outer wall of the independent annular detection cavity 60 is made of sapphire, with a diameter of 12mm and a thickness of 3mm. The sapphire material has a transmittance of more than 85% for 280nm ultraviolet light. The window is sealed and installed on the outer wall of the independent annular detection cavity 60 by flange clamping.

[0059] Light receiving end structure: An optical window with a diameter of 8mm is opened at the center height of the independent annular detection cavity 60 in the equal-diameter section of the expanded diameter section of the hollow rotating spindle 30. A sapphire window plate with a diameter of 8mm and a thickness of 2mm is embedded in the window, and the window plate is sealed to the wall of the hollow rotating spindle 30 by laser welding.

[0060] A quartz optical fiber with a core diameter of 3 mm and a numerical aperture of 0.22 is connected to the inner side of the sapphire window (the inner cavity side of the hollow rotating spindle 30). The fiber end face is ground and polished and optically coupled to the window, with a coupling efficiency greater than 80%. The fiber passes through the central fiber channel of the hollow rotating spindle 30, exits from the optical rotary connector at the upper end of the hollow rotating spindle 30, and connects to a dual-channel spectrometer outside the rotating focusing ultrasonic reactor.

[0061] Synchronization triggering mechanism: Since the light source is fixed while the light-receiving end rotates with the hollow rotating spindle 30, the light signal can only be effectively transmitted when the hollow rotating spindle 30 rotates to a specific angle so that the light-receiving window is aligned with the light source. To achieve precise synchronous detection, a Hall sensor is installed on the hollow rotating spindle 30, and a permanent magnet is installed on the rotating support of the hollow rotating spindle 30. Each time the hollow rotating spindle 30 rotates one revolution and the light-receiving window is aligned with the light source, the Hall sensor outputs a pulse signal.

[0062] The pulse signal is input to the PLC controller, which triggers the spectrometer for rapid acquisition, with a single exposure time of 50ms. During the detection phase, the rotation speed of the hollow rotating spindle 30 is reduced to 60rpm, rotating once per second and aligning once, providing a more sufficient alignment time window and more stable measurement conditions for optical signal acquisition. The system can continuously acquire spectra three times within one alignment cycle and take the average value, completing a full detection in approximately 10-15 seconds (including multiple sampling cycles). After detection, the system automatically returns to the normal reaction speed. This optical detection system adopts a cyclical working mode of "stabilization-rotation-alignment-sampling": the stabilization phase refers to the brief static period after the sample is filled into the independent annular detection cavity 60 and before detection begins, used to eliminate the interference of liquid flow on optical measurement; the rotation phase involves the hollow rotating spindle 30 driving the light-collecting end to rotate continuously, periodically aligning the light-collecting window radially with the fixed light source 70; at the moment of alignment, the Hall sensor outputs a pulse signal to trigger the spectrometer for rapid acquisition, completing the capture of the optical signal. This system achieves high-precision spectral detection during the brief alignment moment of each revolution of the hollow rotating main shaft 30 by coordinating a fixed light source and a rotating light receiving end. This ensures measurement accuracy while enabling online real-time monitoring of the rotating system with a simplified configuration of a single light source and a single optical fiber.

[0063] Detection principle and conversion rate calculation: Excitation light is emitted from a fixed light source 70, focused by a collimating lens, passes through a sapphire window on the outer wall of an independent annular detection cavity 60, passes through the sample liquid inside the independent annular detection cavity 60, is collected by the sapphire window on the side of the hollow rotating spindle 30 and the optical fiber, and is transmitted to a dual-channel spectrometer.

[0064] The spectrometer simultaneously measures: (1) ultraviolet absorption spectrum, extracts absorbance at wavelengths of 290 nm and 283 nm, and calculates the absorption peak ratio A. 290 / A 283 (2) Fluorescence emission spectrum: extract the fluorescence intensity at wavelengths of 340 nm and 320 nm, and calculate the fluorescence ratio F. 340 / F 320 .

[0065] Based on a pre-established calibration model, the debittering conversion rate of naringinase was calculated by a linear combination of the absorption peak ratio and the fluorescence ratio. This model was obtained by offline HPLC determination of standard samples with different conversion rates, combined with multiple linear regression fitting of spectral characteristic parameters.

[0066] By adjusting the operating parameters of the rotary focusing ultrasonic reactor (rotation speed of the hollow rotating spindle 30, ultrasonic frequency, ultrasonic power, and running time), the liquid in the internal and external spatial regions of the rotary focusing ultrasonic reactor can be selectively guided to the independent annular detection chamber 60 for online detection, thereby realizing the conversion rate monitoring of multi-point spatial distribution within the rotary focusing ultrasonic reactor and evaluating the reaction uniformity.

[0067] The negative pressure sampling system consists of: The sampling hole on the upper end cover of the independent annular detection chamber 60 is connected to the eccentric negative pressure channel inside the hollow rotating spindle 30 via a pipeline. The eccentric negative pressure channel extends spirally upward from the lower end of the hollow rotating spindle 30 (the location of the independent annular detection chamber 60) to the upper end of the hollow rotating spindle 30, where it connects to the negative pressure rotary joint.

[0068] The sampling / cleaning rotary joint features a dynamic-static sealing structure with an inner diameter of 8mm. It employs silicon carbide dynamic-static ring seals and operates within a pressure range of -0.08MPa to 0.3MPa. The stationary end of the rotary joint connects to a three-way solenoid switching valve assembly. The sampling line connects to an electric regulating valve via a hose, which precisely controls the negative pressure. This valve then connects to a vacuum buffer tank and a vacuum pump. The vacuum buffer tank stabilizes the negative pressure and prevents liquid backflow into the vacuum pump. The cleaning line connects to a pure water supply system via a hose, equipped with a pressure regulating valve (set pressure 0.25MPa) and a flow meter to ensure a stable flow rate of cleaning fluid to the independent annular detection chamber 60. The switching valve assembly is PLC-controlled with a response time of less than 0.5 seconds, ensuring rapid and reliable switching between sampling and cleaning modes.

[0069] Selective sampling principle: The liquid inside the rotating focusing ultrasonic reactor is subjected to multiple flow driving forces: (1) centrifugal force and circumferential shear force generated by the rotation of the hollow rotating main shaft 30; (2) acoustic flow effect generated by the ultrasonic sound pressure gradient; (3) axial and radial driving force generated by the helical blades; and (4) natural convection caused by density difference and temperature gradient. These forces together form a complex three-dimensional flow field inside the rotating focusing ultrasonic reactor.

[0070] Through systematic experiments and fluid dynamics simulations, two typical spatial regions within the rotating focusing ultrasonic reactor and their corresponding flow field control parameters were determined: P1 Area (Central Rapid Response Zone): Spatial location: The central columnar region adjacent to the hollow rotating main axis, containing the central part of the entrance to the parabolic internal ultrasonic focusing core reaction zone and the spiral hybrid enhancement zone.

[0071] Features: This area is adjacent to the independent annular detection cavity with a 60 sampling port, where the ultrasonic intensity is the highest and the response rate is the fastest.

[0072] Sampling conditions: No special flow field control is required. Under normal reaction parameters, such as (hollow rotating spindle 30 rotation speed 60-100 rpm, ultrasonic frequency 20-28 kHz), the liquid in this area can directly enter the independent annular detection chamber 60 through the sampling port under negative pressure.

[0073] Flow field control parameters: hollow rotating spindle 30 rpm, ultrasonic frequency off or 20 kHz low power (50 W), pre-rotation time 20 seconds, sampling negative pressure -45 kPa.

[0074] P2 area (peripheral mixed representative area): Spatial location: The outer annular region approximately 200-350 mm from the hollow rotating main axis, including the outer perimeter of the spiral mixing zone, the near-wall flow boundary layer, and the main reaction volume in the lower part of the tank.

[0075] Characteristics: This region is far from the ultrasonic focusing center and has a relatively slow reaction rate, but it accounts for about 70% of the total volume of the rotating focusing ultrasonic reactor and is representative of the whole.

[0076] Sampling conditions: The liquid in this area needs to be driven to the sampling port through parameter control. By increasing the rotation speed of the hollow rotating spindle 30, a strong centrifugal effect is generated. Combined with the acoustic flow effect of ultrasound at a specific frequency, the peripheral liquid flows radially towards the center and is guided by the spiral blades to the vicinity of the sampling port of the independent annular detection chamber 60, and then enters the independent annular detection chamber 60 through the sampling port.

[0077] Flow field control parameters include: hollow rotating spindle 30, rotation speed 180 rpm (high-speed centrifugation), ultrasonic frequency 35 kHz (medium-high frequency acoustic flow effect), ultrasonic power 250 W, pre-rotation time 75 seconds, and sampling negative pressure -55 kPa.

[0078] The significance of dual-region detection: The P1 region represents the region with the fastest reaction and can be used to monitor the maximum rate of progress of the enzyme-catalyzed reaction. The P2 region represents the overall reaction progress and reflects the average conversion level of the main volume of the rotating focusing ultrasonic reactor. The difference in conversion rates between the two regions reflects the uniformity of the reaction: the smaller the difference, the better the uniformity. By using dual-region comparative monitoring, the mixing effect can be evaluated in real time and operating parameters can be optimized.

[0079] Single-area sampling process: The complete process for sampling and detecting any target area includes the following steps: Parameter recording and switching preparation: The PLC records the current operating parameters of the rotary focusing ultrasonic reactor, starts the vacuum pump and adjusts it to the negative pressure value corresponding to the target area; Field adjustment: Switch the hollow rotating spindle speed and ultrasonic parameters to the corresponding values ​​of the target area (e.g., 80 rpm for P1 area or 180 rpm for P2 area), maintain the pre-rotation time, and adjust the flow field to the steady state of the liquid reaching the sampling port in the target area. Negative pressure sampling: Open the solenoid valve of the sampling port of the independent annular detection chamber 60, and draw liquid into the independent annular detection chamber 60 under the set negative pressure until the independent annular detection chamber 60 is filled to an effective volume of 150mL; Spectral detection: Close the sampling port solenoid valve, and after the liquid in the independent annular detection chamber 60 stabilizes, reduce the spindle speed to 60 rpm and perform spectral acquisition. The PLC calculates the conversion rate in real time based on the spectral data. Drainage and cleaning: Open the bottom drain valve of the independent annular detection chamber 60 to drain the liquid in the independent annular detection chamber 60 back to the main reaction tank 10; switch the PLC to the cleaning mode of the three-way solenoid valve, and pure water enters the independent annular detection chamber 60 through the eccentric channel and sampling port inside the hollow rotating spindle 30. After rinsing for 20 seconds, it is discharged from the drain valve. Repeat the rinsing twice; after cleaning, switch the PLC to the sampling mode of the three-way solenoid valve; Parameter restoration: restore the operating parameters of the rotary focusing ultrasonic reactor to the normal reaction state before sampling.

[0080] Dual-area scanning monitoring: When it is necessary to assess the uniformity of conversion rate distribution within a rotating focusing ultrasonic reactor, sampling and testing are performed on the two regions sequentially in the order of P1→P2, completing one dual-region scan. The total time for a single dual-region scan is approximately 6-8 minutes.

[0081] The PLC system calculates the arithmetic mean of the conversion rates of the two regions, the difference in conversion rates (ΔC), and the uniformity coefficient.

[0082] When the uniformity coefficient is lower than the preset threshold, the system automatically adjusts the temperature control, stirring or ultrasonic parameters to improve the uniformity of the reaction.

[0083] II. Method for Debittering Naring Peel Using a Rotating Focusing Ultrasonic Reactor with Enzymatic Approach 2.1 Preparation of grapefruit extract 200 kg of fresh pomelos were selected. The varieties could be one or more, including red-fleshed, white-fleshed, golden, or grapefruit. After washing, the pulp and peel were separated. The peel was cut into 5mm x 5mm pieces, and the pulp was seeded and crushed. The processed pomelo raw material was placed into an extraction tank equipped with a multi-frequency ultrasonic generator, and purified water was added for ultrasonic-assisted extraction. After extraction, the extract was centrifuged and filtered to obtain a clear extract. HPLC analysis showed that the naringin content was 1.82 g / L.

[0084] 2.2 Preparation and initialization of the reaction system 300L of grapefruit extract and 100L of purified water were added to the main reaction vessel 10 of the rotary focusing ultrasonic reactor, with a total reaction volume of 400L and a liquid level of approximately 800mm. The pH of the reaction solution was adjusted to 7.0-7.5 using an alkaline adjuster selected from one of 2M sodium hydroxide solution, sodium carbonate solution, sodium bicarbonate solution, or disodium hydrogen phosphate buffer solution. The jacketed circulating heating system of the vessel was started to raise the temperature of the reaction solution to 45℃ and stabilize it.

[0085] Weigh 240g of glycosidase (enzyme activity 5000U / g), wherein the glycosidase is selected from one or more of α-rhamnosidase, cellobiase, naringinase, or a mixed glycosidase preparation, preferably α-rhamnosidase, and the amount of enzyme added is 0.08% of the mass of the extract. Dissolve the enzyme powder in purified water, activate it at room temperature, and then add it to the reaction solution through the top feed port of the main reaction tank 10.

[0086] Start the stirring and ultrasonic system of the rotary focusing ultrasonic reactor. The initial operating parameters are: hollow rotating spindle 30 rpm, ultrasonic frequency 20 kHz, ultrasonic power 300 W, ultrasonic duty cycle 70% (work for 7 seconds, stop for 3 seconds, repeat to avoid overheating).

[0087] Before the reaction is started, the independent annular detection chamber 60 is cleaned by rinsing it three times with pure water.

[0088] 2.3 Staged Reaction Process Control The enzymatic debittering reaction of naringin adopts a four-stage stepwise control strategy based on real-time online detection. The reaction parameters are adjusted in real time according to the conversion rate detected by dual-region sampling to achieve precise control.

[0089] 2.3.1 Phase 1: Gentle Start-up Period (0-15 minutes) This stage employs mild reaction conditions to ensure sufficient contact between the enzyme and substrate and to initiate the reaction. The control parameters are: hollow rotating spindle 30°C at 60 rpm, ultrasonic frequency 20 kHz, ultrasonic power 300 W, reaction temperature 45°C, and pH 7.2.

[0090] In the early stages of the reaction, the P1 region (central rapid reaction zone) is sampled and tested periodically to monitor the reaction start-up and the rate of conversion increase.

[0091] At the 15-minute mark, a dual-region scanning procedure is initiated, sequentially sampling and detecting regions P1 and P2. The system calculates the average conversion rate, the difference in conversion rate, and the uniformity coefficient between the two regions to assess reaction uniformity.

[0092] Based on the results of the dual-region scan: If the difference in conversion rates between P1 and P2 is too large (ΔC>8%), it indicates that the mixing is insufficient. The system will automatically increase the speed of the hollow rotating spindle from 30 rpm to 100 rpm to enhance the overall mixing.

[0093] If the conversion rate in region P2 is low and the temperature is abnormal, the system will automatically increase the temperature of the jacket circulating water to improve the reaction conditions in the outer region.

[0094] 2.3.2 Phase Two: Rapid Response Period (15-50 minutes) This stage is the period of rapid increase in conversion rate, and medium-intensity ultrasound and stirring are used to enhance mass transfer. Based on the optimization results of stage one, the control parameters are adjusted as follows: hollow rotating spindle 30 rpm, ultrasonic frequency 28 kHz (medium frequency mass transfer effect is better), ultrasonic power 200 W, reaction temperature 46 ℃, and pH value 7.0.

[0095] A dual-region scan is performed every 10 minutes to monitor the conversion rate trends in regions P1 and P2, ensuring that uniformity is improved after parameter optimization.

[0096] When the conversion rate of the P2 area (outer representative area) reaches about 45%, the system judges that the overall response is close to 75% of the target progress and triggers the entry into stage three.

[0097] 2.3.3 Phase Three: Precision Control Period (50-70 minutes) This stage is a period of precise control close to the target conversion rate, requiring high-frequency monitoring and precise control of the endpoint. High-speed, low-power ultrasound is used to avoid over-reaction. The control parameters are: hollow rotating spindle 30 rpm (high-speed mixing and homogenization), ultrasound frequency 40 kHz (high-frequency gentle action), ultrasound power 100 W (low power), reaction temperature 44℃ (slight cooling to slow down the reaction rate), and pH value 7.0.

[0098] A dual-region scan is performed every 5 minutes to closely monitor the changing trends of conversion rates and reaction rates in both regions.

[0099] When the conversion rate of the P2 region reaches 55-58% and the difference between the conversion rates of P1 and P2 is reduced to within 5%, the system determines that the overall reaction has reached the target endpoint and automatically triggers the enzyme inactivation program.

[0100] 2.3.4 Stage Four: Rapid Enzyme Inactivation Period When online dual-region detection shows that the conversion rate reaches the target value and the uniformity is good, immediately stop the ultrasonic system and increase the rotation speed of the hollow rotating spindle from 30 rpm to 200 rpm to enhance heat transfer. Introduce 85°C steam through the tank jacket to rapidly raise the temperature of the reaction solution to 85°C and maintain it for 5 minutes to completely inactivate α-rhamnosidase.

[0101] After enzyme inactivation, the reaction solution is rapidly cooled to 40°C using a jacketed circulating cooling water system.

[0102] After the reaction was completed, samples were taken for HPLC analysis to verify the results: naringin residue was 0.78 g / L (initial concentration 1.82 g / L), naringenin (debittered product) concentration was 0.95 g / L, and the overall conversion rate was 57.1%. The final dual-region detection results were: P1 region 60.3%, P2 region 56.8%, conversion rate difference 3.5%, uniformity coefficient 0.94. The deviation between the HPLC-detected conversion rate (57.1%) and the average value of the dual-region online optical detection (58.6%) was less than 3%, verifying the accuracy and reliability of the online detection system.

[0103] III. Preparation of Functional Grapefruit Dairy Products 3.1 Standardized Milk Preparation Take 1000L of dairy product base material, wherein the dairy product base material is selected from one or more of whole milk, skim milk, partially skimmed milk, reconstituted milk, or soy milk, preferably whole milk, and stir and hydrate it at 55°C. Add a stabilizer system, wherein the stabilizer system comprises: Thickening stabilizer 0.3-0.6%, selected from one or more of pectin, xanthan gum, gelatin or sodium alginate, preferably a compound of 0.3% pectin and 0.2% carrageenan; Sweetener 6-10%, selected from one or more of white sugar, fructose, sucrose, isomaltitol or steviol glycosides, preferably 8% white sugar, heated to 75°C and stirred to gel, then cooled to 40°C for later use.

[0104] 3.2 Compounding and Post-processing Grapefruit extract, after enzymatic debittering, is blended with standardized milk at a mass ratio of 5:95 to 10:90, preferably 7:93. For example, 70L of grapefruit extract is mixed with 930L of standardized milk, and the final pH of the mixture is 6.65. After two-stage high-pressure homogenization (stage 18MPa, stage 5MPa, temperature 65℃), the mixture is sterilized by UHT (137℃ / 4 seconds) and aseptically filled into 200mL Tetra Pak cartons to obtain functional grapefruit dairy products.

[0105] This product significantly reduces the bitterness of naringin while retaining the flavor of grapefruit and its active ingredients (vitamin C and flavonoids), resulting in a smooth taste and excellent nutritional and functional properties.

[0106] This embodiment fully verifies the technical feasibility and application value of the rotating focusing ultrasonic reactor and its multi-region selective sampling and detection system of the present invention through specific process parameters and detailed operating procedures. Furthermore, this embodiment can be extended to other enzymatic reactions, chemical transformation reactions, or extraction and separation processes requiring ultrasound enhancement, especially in situations requiring real-time monitoring of reaction progress and assessment of spatial uniformity. By adjusting parameters such as reactor size, ultrasonic parameters, flow field control methods, and detection wavelength, it can adapt to the processing needs of different raw materials, different reaction systems, and different products.

Claims

1. A rotary focusing ultrasonic reactor with multi-region selective sampling function, characterized in that, include: The main reaction vessel (10) has an ultrasonic transducer (20) installed on its wall. A hollow rotating spindle (30) passes through the top of the main reaction vessel (10) and is connected to the drive device. The hollow rotating spindle (30) is provided with an enlarged diameter section and the inner cavity is provided with at least one channel. A rotating parabolic focusing reflector (40) is fixed on the hollow rotating main shaft (30) and rotates accordingly. The rotating parabolic focusing reflector (40) has a parabolic structure with an opening facing downwards. Its inner surface is an ultrasonic reflecting surface. The ultrasonic waves emitted by the ultrasonic transducer (20) enter from the opening of the rotating parabolic focusing reflector (40) and are focused and reflected on the inner surface of the parabolic surface. An independent annular detection cavity (60) is fitted around the expanded section of the hollow rotating main shaft (30) and rigidly fixed thereto. It rotates synchronously with the hollow rotating main shaft (30). The independent annular detection cavity (60) is provided with a sampling port and is connected to an external sampling system through the inner cavity channel of the hollow rotating main shaft (30). The online optical inspection system includes a light source (70) fixed inside the main reaction vessel (10), a light-transmitting window at the light source end set on the outer wall of the independent annular inspection cavity (60), a light-receiving window at the light-receiving end set on the hollow rotating main shaft (30) and radially corresponding to the light-transmitting window at the light source end, and an optical transmission component that transmits the optical signal to the external optical inspection device (80) through the inner cavity channel of the hollow rotating main shaft (30). The multi-region selective sampling system changes the flow field distribution within the reactor by adjusting the reactor operating parameters, so that liquids in different spatial regions are driven to the independent annular detection chamber (60) for online detection.

2. The rotating focusing ultrasonic reactor according to claim 1, characterized in that, The hollow rotating spindle (30) has two independent channels in its inner cavity: a central optical fiber channel and an eccentric sampling / cleaning channel; a rotary joint is installed at the upper end of the hollow rotating spindle (30), and the eccentric sampling / cleaning channel is connected to a three-way electromagnetic switching valve group through the rotary joint. One of the valve groups is connected to a vacuum pump system for negative pressure sampling, and the other is connected to a cleaning fluid supply system for cleaning water supply.

3. The rotating focusing ultrasonic reactor according to claim 1, characterized in that, It also includes a spiral hybrid reinforcement zone, which is located directly below the rotating parabolic focusing reflector (40) and coaxially mounted with the hollow rotating main shaft (30), including a double spiral guide tube (50) and a built-in double spiral blade assembly (51).

4. The rotating focusing ultrasonic reactor according to claim 1, characterized in that, The ultrasonic transducers (20) are evenly arranged around the tank wall, and the emission direction is designed to be inclined upward.

5. The rotating focusing ultrasonic reactor according to claim 1, characterized in that, The multi-region selective sampling system achieves selective sampling of at least two different spatial regions by adjusting the rotational speed of the hollow rotating spindle (30), the ultrasonic frequency, the ultrasonic power, and the pre-rotation time.

6. The rotating focusing ultrasonic reactor according to claim 5, characterized in that, The at least two distinct spatial regions include: P1 region: The central region adjacent to the hollow rotating main axis (30), which includes the internal ultrasonic focusing core reaction zone of the parabolic surface; P2 area: the outer area 200-350mm away from the hollow rotating main shaft (30).

7. A method for debittering naringinase in naringin peel using a rotating focusing ultrasonic reactor as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Add the grapefruit extract containing naringin into the main reaction vessel (10), adjust the pH value and raise the temperature; (2) Add glycosidase and start the stirring and ultrasonic system of the rotating focusing ultrasonic reactor; (3) During the reaction, different spatial regions are sampled by a multi-region selective sampling system, and the conversion rate of naringin is monitored in real time by an online optical detection system; (4) Adjust the reaction parameters according to the online detection results, and perform enzyme inactivation treatment when the conversion rate reaches the target value.

8. The method according to claim 7, characterized in that, In step (3), at least two different spatial regions are sampled and detected, the average value and difference of the conversion rate of each region are calculated, and the reaction uniformity is evaluated.

9. The method according to claim 8, characterized in that, The reaction process employs a staged control strategy, including: The hollow rotating spindle (30) speed, ultrasonic frequency and ultrasonic power are adjusted in real time according to the online detection conversion rate during the mild start-up period, rapid reaction period, precise control period and rapid enzyme inactivation period.

10. A method for preparing a functional grapefruit dairy product, characterized in that, The grapefruit extract is subjected to enzymatic debittering treatment using the method described in any one of claims 7-9. The treated grapefruit extract is then compounded with dairy product base, homogenized, sterilized, and filled to obtain functional grapefruit dairy products.

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