High-absorption carrot juice processing control method based on multi-stage quality detection

Abstract

The application discloses a high-absorption carrot juice processing control method based on multi-stage quality detection, and relates to the technical field of food processing. The method comprises the following steps: raw material acceptance and initial physical property detection; low-temperature color protection pretreatment; dynamic pressing and initial filtration; enzyme solubilization treatment to release embedded carotenoids; three-stage high-pressure homogenization to reduce the D[4,3] particle size to below 380 nanometers; instantaneous high-temperature sterilization to promote interface membrane reconstruction; multi-stage quality online detection is implemented at four key nodes; closed-loop parameter feedback adjustment is realized based on detection data through a multivariate regression model; and finally, sterile cold filling and light-proof aging are performed. Through the technical scheme, the application significantly improves the carotenoid retention rate, oxidation stability and in-vitro gastrointestinal simulation absorption rate, the final product absorption rate is stably above 42%, the retention rate is above 92%, and no organic solvent or non-original juice processing means is needed, so the application is suitable for industrialized production of high-value-added pure carrot juice.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a method for controlling the processing of highly absorbable carrot juice based on multi-stage quality testing. Background Technology

[0002] With the continuous upgrading of the functional food industry, natural fruit and vegetable juices rich in carotenoids have become an important growth point in the health beverage market due to their physiological activities in antioxidation, immune regulation, and visual health maintenance. Carrots, as an excellent plant source of β-carotene, produce juice that not only has high nutritional value but is also widely used in nutritional fortification and dietary intervention due to its ability to be converted into vitamin A. However, carotenoids are fat-soluble compounds with low solubility and poor stability in aqueous systems, and their bioavailability is highly dependent on the synergistic regulation of their physical form, particle dispersion, and matrix microenvironment during processing. Therefore, how to improve the intestinal absorption efficiency of carotenoids in carrot juice by optimizing the process while preserving natural components has become a core challenge in the research and development of high-value-added functional juices.

[0003] The processing control of highly absorbable carrot juice focuses on the dynamic coupling relationship between key physical properties and the release efficiency of active ingredients throughout the entire chain from raw materials to finished product. This technological direction aims to improve the microparticle dispersibility of carotenoids, reduce the risk of oxidative degradation, and enhance their release and micellization capabilities in simulated gastrointestinal fluids by precisely controlling unit operations such as juicing, homogenization, enzymatic hydrolysis, and heat treatment. Ideally, the process should enable carotenoids to exist in the juice system as stable nano- or submicron-sized dispersions, thereby significantly improving their uptake efficiency in small intestinal epithelial cells. However, existing processing methods generally lack systematic process support and feedback mechanisms to achieve this goal.

[0004] While existing technologies have made various attempts to improve the bioavailability of carotenoids, significant limitations remain. On one hand, some solutions, such as those described in CN110876258B, introduce carrot juice as a flavor-enhancing component, but their core process revolves around the low-temperature aging of beetroot juice. They fail to design specific process pathways tailored to the cell wall structure of carrots, the state of carotenoids, and processing sensitivity, nor do they establish absorption-oriented quality testing points at each stage after juicing. On the other hand, while the microencapsulation technology disclosed in CN111903846B can effectively improve the stability and bioavailability of carotenoids, it relies on non-juice processing methods such as organic solvent extraction, high-temperature emulsification, and spray drying, violating the principles of clean labeling and minimal processing, making it unsuitable for high-absorption products positioned as 100% carrot juice. More importantly, neither of these technologies has established a multi-stage quality testing system covering raw material acceptance, pretreatment, juicing, homogenization, enzymatic hydrolysis, sterilization to filling. This makes it impossible to monitor key indicators such as carotenoid content, particle size distribution D[4,3], oxidation induction time (OIT), soluble solids, and in vitro gastrointestinal simulated absorption rate in real time and adjust process parameters in a closed loop. As a result, the final product exhibits large batch-to-batch fluctuations and insufficient stability in terms of absorption performance. Summary of the Invention

[0005] The purpose of this invention is to provide a high-absorption carrot juice processing control method based on multi-stage quality testing, in order to solve the technical problems of existing carrot juice processing technology lacking a systematic regulatory mechanism for the bioavailability of carotenoids and failing to establish a multi-stage quality testing system covering the entire process chain, resulting in large batch fluctuations, low absorption efficiency and uncontrollable issues in the final product in terms of carotenoid dispersion stability, oxidative resistance and in vitro gastrointestinal simulated absorption rate.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A processing control method for highly absorbable carrot juice based on multi-stage quality detection includes the following specific steps: Step S1: Raw material acceptance and initial physical property testing. Collect fresh carrot raw materials and determine their initial β-carotene content, soluble solids concentration, cellulose enzymatic hydrolysis potential index and surface microbial load. Select raw materials that meet the preset thresholds to enter the subsequent processing flow. Among them, the β-carotene content is not less than 8.5 mg per 100g fresh weight, the soluble solids concentration is between 9.0 and 12.0°Brix, the enzymatic hydrolysis potential index is greater than or equal to 75%, and the total number of surface colonies is less than 3.0 x 10^4 CFU per gram. Step S2: Low-temperature color protection pretreatment. The washed and peeled carrot pieces are immersed in a compound color protection solution of ascorbic acid and citric acid at a temperature of 4 degrees Celsius and a pH of 4.2 for 12 minutes to inhibit polyphenol oxidase activity and maintain the integrity of cell wall structure. Then, ultrasonic-assisted rinsing is performed to remove residual color protection agent and particulate impurities on the surface. Step S3: Dynamic pressing and primary filtration. A variable frequency controlled screw press is used to perform segmented pressing at a speed of 28 revolutions per minute and a pressure gradient of 0.6 MPa to 1.2 MPa. After collecting the original juice, it is initially filtered through a stainless steel screen with a pore size of 200 micrometers to obtain primary carrot juice with a clarity of not less than 65%. Step S4: Enzymatic hydrolysis and solubilization treatment. Add pectinase and cellulase complex enzyme preparation to the primary juice at a concentration of 30 mg / L and 20 mg / L, respectively. Enzymatic hydrolysis is carried out for 90 minutes at a temperature of 45 degrees Celsius and a pH of 3.8 to degrade the residual polysaccharide network of the cell wall, release embedded carotenoids and improve their aqueous dispersibility. Step S5: High-pressure homogenization and nano-dispersion. The enzymatically hydrolyzed juice is processed by a three-stage high-pressure homogenizer. The first stage homogenization pressure is set at 30 MPa, the second stage at 50 MPa, and the third stage at 70 MPa, so that the particle size of carotenoid particles D[4,3] is reduced to below 380 nm and a submicron stable emulsion system is formed. Step S6: Heat activation sterilization and structural shaping. A short-time high-temperature sterilization process is used, which is maintained at 98 degrees Celsius for 25 seconds to inactivate residual enzymes and microorganisms. At the same time, it promotes the reconstruction of the protein-polysaccharide interface film on the oil droplet surface and enhances the steric stability of the emulsion droplet. Step S7: Multi-stage online quality detection. At four key nodes, namely raw material acceptance, end of enzymatic hydrolysis, completion of homogenization and before sterilization and filling, samples are collected simultaneously to measure five core indicators: carotenoid retention rate, D[4,3] particle size distribution, oxidation induction time, soluble solids change rate and in vitro gastrointestinal simulated absorption rate. The data are then uploaded to the central process control system. Step S8: Closed-loop parameter feedback adjustment. Based on the data deviation of each detection node, a multivariate regression model is constructed to calculate the process compensation coefficient. When any index exceeds the preset tolerance range, the operating parameters of the next process are automatically adjusted to achieve dynamic optimization and closed-loop quality control of the processing process. Step S9: Aseptic cold filling and light-proof storage. The final qualified juice is filled into brown glass bottles sterilized by ultraviolet irradiation in an environment with a cleanliness level of not less than B. After sealing, the bottles are immediately placed in a constant temperature warehouse with a temperature of 4 degrees Celsius and a light intensity of less than 50 lux for 72 hours to complete the final quality stabilization of the product.

[0007] Preferably, the β-carotene content in step S1 is determined by high performance liquid chromatography, with the mobile phase being a methanol-acetonitrile-dichloromethane mixture, the detection wavelength being 450 nm, the linear correlation coefficient R-squared of the standard curve being greater than or equal to 0.9995, and the limit of quantitation being 0.1 mg per 100 g fresh weight.

[0008] Preferably, in step S2, the concentration of ascorbic acid is 0.8 g / L, the concentration of citric acid is 1.2 g / L, the conductivity of the composite color-protecting solution is 1.8 mSiemens per centimeter, the ultrasonic rinsing frequency is 40 kHz, the power density is 0.6 W / mL, and the duration is 3 minutes.

[0009] Preferably, in step S4, the pectinase activity is not less than 200 units per milligram, the cellulase activity is not less than 150 units per milligram, and nitrogen gas is continuously introduced during the enzymatic hydrolysis reaction to maintain the oxygen partial pressure below 0.5 kPa to prevent the oxidative degradation of carotenoids.

[0010] Preferably, in step S5, the working gap of the high-pressure homogenizer is 0.1 mm, the cooling water flow rate is maintained at 12 liters per minute to control the outlet temperature to not exceed 40 degrees Celsius, and the continuous processing flow rate is 1.5 cubic meters per hour to ensure the uniformity of the shearing field.

[0011] Preferably, in step S7, the oxidation induction time is determined by differential scanning calorimetry, with a heating rate of 10 degrees Celsius per minute, an initial temperature of 50 degrees Celsius, and an ending temperature of 200 degrees Celsius. The time of the exothermic peak is recorded as the OIT value, and the final product OIT is required to be no less than 180 minutes.

[0012] Preferably, in step S7, the in vitro gastrointestinal simulated absorption rate is performed according to the improved INFOGEST2.0 protocol, simulating the digestion stages of the mouth, stomach and small intestine. After digestion, the micelle phase is separated by centrifugation, and the carotenoid content is measured. The absorption rate is calculated as follows: absorption rate = (mass of micelle phase carotenoids / mass of total carotenoids) × 100%, and the target absorption rate is not less than 42%.

[0013] Preferably, the multivariate regression model expression in step S8 is: Where Y represents the output value of the process parameter to be adjusted. to This indicates the degree to which each detection node deviates from the standard value. to The regression coefficients are obtained by training with historical data, and the model's prediction accuracy is greater than or equal to 93%.

[0014] Preferably, in step S8, when the particle size of D[4,3] exceeds 400 nanometers, the system automatically triggers a recirculation homogenization command to return the material to the homogenization process for secondary processing until it meets the standard; when the predicted value of in vitro absorption rate is less than 40%, the amount of emulsifying stabilizer xanthan gum added is automatically increased to 0.08%, and the nitrogen protection time is extended by 10 minutes.

[0015] Preferably, in step S9, the light transmittance of the brown glass bottle is no more than 5% in the 400 to 500 nanometer wavelength range, the relative humidity of the filling environment is controlled at 55% ± 5%, and the composition of the headspace gas inside the bottle is monitored regularly during the aging period, and the increase in oxygen concentration is not more than 15% of the initial value.

[0016] Preferably, it also includes establishing a full-process quality database to store all testing data and process parameters for each batch from raw materials to finished products, with a data sampling frequency of no less than once every 10 minutes and a total number of records greater than or equal to 12,000, to support long-term trend analysis and process iteration optimization.

[0017] Preferably, the method is applicable to an industrial production line for fresh carrot raw materials with a daily processing capacity of not less than 10 tons. The whole system integrates an automated control system and a remote monitoring platform. The processing time for a single batch is controlled within 4.5 hours. The carotenoid retention rate of the product is stable at over 92%. The D[4,3] particle size is controlled within the range of 350 nm ± 30 nm. The average in vitro gastrointestinal simulated absorption rate reaches 44.6%.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention constructs a multi-stage quality testing system that spans the entire process from raw material acceptance, pretreatment, enzymatic hydrolysis, homogenization, sterilization to filling, enabling dynamic monitoring and closed-loop data feedback of key indicators such as carotenoid content, particle size distribution D[4,3], oxidation induction time, soluble solids, and in vitro gastrointestinal simulated absorption rate.

[0019] This invention is the first to take absorption efficiency as the core process-oriented target, and through the synergistic effect of enzymatic hydrolysis solubilization, high-pressure homogenization and heat-activated sterilization, it significantly improves the particle dispersion state and interfacial stability of carotenoids; the three-stage progressive high-pressure homogenization process keeps the D[4,3] particle size stably controlled below 380 nm, forming a submicron dispersion system that is conducive to micelle formation; the enzymatic hydrolysis process effectively destroys the residual structure of the cell wall and releases the embedded active ingredients; the instantaneous high-temperature treatment not only ensures food safety, but also promotes the rearrangement of the protein-polysaccharide composite film on the surface of oil droplets, enhancing the long-term storage stability of the system.

[0020] This invention utilizes a closed-loop adjustment mechanism driven by a multivariate regression model, combined with data acquisition at multiple detection nodes, to dynamically compensate processing parameters based on real-time quality performance, significantly reducing batch-to-batch variations. Experimental data show that the final product exhibits a carotenoid retention rate exceeding 92%, an oxidation induction time exceeding 180 minutes, and an in vitro gastrointestinal simulated absorption rate consistently above 42%, reaching a maximum of 44.6%, significantly superior to the 28% to 35% absorption rate of products processed using conventional methods.

[0021] This invention is based entirely on physical and biological enzymatic processing, without the need for non-juice processing methods such as organic solvent extraction or spray drying. It complies with the principles of clean labeling and minimal processing and is suitable for the industrial production of high-value-added functional beverages made from 100% pure carrot juice. It solves the fundamental contradictions of existing technologies, such as uncontrollable absorption performance, poor stability, and process paths that deviate from natural properties. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall technical solution architecture of the high-absorption carrot juice processing control method based on multi-stage quality detection proposed in this invention; Figure 2 This is a schematic diagram of the process control method for high-absorption carrot juice based on multi-stage quality detection proposed in this invention. Detailed Implementation

[0023] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present invention and not to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present invention by illustrating examples of the invention.

[0024] Example 1 To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0025] Currently, against the backdrop of the continuous upgrading of the functional food industry, natural fruit and vegetable juices rich in carotenoids have become an important growth point in the health beverage market due to their physiological activities in antioxidation, immune regulation, and visual health maintenance. Carrots, as an excellent plant source of β-carotene, produce juice that not only has high nutritional value but is also widely used in nutritional fortification and dietary intervention due to its ability to be converted into vitamin A. However, carotenoids are fat-soluble compounds with low solubility and poor stability in aqueous systems, and their bioavailability is highly dependent on the synergistic regulation of their physical form, particle dispersion state, and matrix microenvironment during processing. Therefore, how to improve the intestinal absorption efficiency of carotenoids in carrot juice by optimizing the process while preserving natural components has become a core challenge in the research and development of high-value-added functional juices. To address the aforementioned technical problems, this invention proposes a high-absorption carrot juice processing control method based on multi-stage quality testing. This method effectively solves the technical problems of existing carrot juice processing processes lacking a systematic regulatory mechanism for the bioavailability of carotenoids and failing to establish a multi-stage quality testing system covering the entire process chain. This results in large batch fluctuations, low absorption efficiency, and uncontrollable issues in the final product regarding carotenoid dispersion stability, oxidative resistance, and in vitro gastrointestinal simulated absorption rate. The method is applied to the high-absorption carrot juice processing control method based on multi-stage quality testing.

[0026] refer to Figure 1 The overall technical architecture of this invention includes a raw material acceptance and initial property testing unit, a low-temperature color-protecting pretreatment unit, a dynamic pressing and primary filtration unit, an enzymatic hydrolysis and solubilization unit, a high-pressure homogenization and nano-dispersion unit, a heat-activated sterilization and structural shaping unit, a multi-stage online quality monitoring unit, a closed-loop parameter feedback adjustment unit, and an aseptic cold filling and light-protected storage unit. These units are sequentially connected to form a complete process flow, and data integration and command issuance are achieved through a central process control system. (Reference) Figure 2 The core principle framework of multi-stage quality inspection and closed-loop parameter feedback adjustment shows that five core indicators are collected simultaneously at four key inspection nodes. After the data is uploaded, the process compensation coefficient is calculated by a multivariate regression model, which drives the automatic adjustment of parameters in the next process to form a closed-loop control loop. Among them, the four key inspection nodes include raw material acceptance, end of enzymatic hydrolysis, completion of homogenization and before sterilization and filling, and the five core indicators include carotenoid retention rate, D[4,3] particle size distribution, oxidation induction time, soluble solids change rate and in vitro gastrointestinal simulated absorption rate.

[0027] Step S1, Raw Material Acceptance and Initial Physical Property Testing: Specifically, fresh carrot raw materials are collected and first undergo visual screening, removing individuals with rotten, insect-infested, mechanically damaged, or skin shrinkage exceeding 15%. The materials then proceed to an automated testing station. At this station, a near-infrared spectrometer is used to rapidly scan each batch of raw materials, acquiring reflectance spectral data in the 900-1700 nm wavelength range. A pre-trained partial least squares regression model is used to predict the β-carotene content, soluble solids concentration, and cellulose enzymatic hydrolysis potential index in real time. Simultaneously, a representative 500g sample is aseptically shredded, and the surface microbial load is determined using the plate count method. The system sets multiple thresholds: β-carotene content not less than 8.5 mg / 100g fresh weight, soluble solids concentration between 9.0 and 12.0 °Brix, enzymatic hydrolysis potential index greater than or equal to 75%, and total surface colony count less than 3.0 × 10⁻⁶. 4 CFU per gram. Raw materials are only allowed to proceed to subsequent processing if all four indicators are met; if any indicator fails to meet the standard, the entire batch of raw materials is diverted to the secondary product processing channel. The β-carotene content was verified offline by high-performance liquid chromatography (HPLC). The mobile phase was a mixture of methanol, acetonitrile, and dichloromethane at a volume ratio of 70:25:5, the flow rate was 1.0 mL / min, the chromatographic column was a C18 reversed-phase column, the detection wavelength was 450 nm, and the linear correlation coefficient R of the standard curve was [value missing]. 2 The concentration is greater than or equal to 0.9995, and the limit of quantification is 0.1 mg per 100g fresh weight. This testing process ensures the consistency of basic quality between batches of raw materials, laying a material foundation for the stable output of subsequent absorption performance.

[0028] Step S2, low-temperature color-protecting pretreatment: Specifically, the carrot raw materials that passed the screening in step S1 are fed into a fully automatic washing and peeling machine to remove the skin and attached mud and sand, obtaining clean carrot chunks. Then, the carrot chunks are transferred to a constant-temperature soaking tank containing a composite color-protecting solution of ascorbic acid and citric acid at a temperature of 4 degrees Celsius and a pH of 4.2, for a soaking time of 12 minutes. The composite color-protecting solution has an ascorbic acid concentration of 0.8 g / L, a citric acid concentration of 1.2 g / L, and a conductivity of 1.8 mSiemens / cm. Its function is to doubly inhibit polyphenol oxidase activity and chelate metal ions, thereby effectively preventing the oxidative degradation of carotenoids in the early stages of processing, while maintaining the integrity of the cell wall pectin network and avoiding excessive softening that would affect subsequent pressing efficiency. After soaking, the material is immediately transferred to an ultrasonic rinsing tank filled with deionized water. The ultrasonic frequency is 40 kHz, the power density is 0.6 W / mL, and the duration is 3 minutes. The microjets generated by ultrasonic cavitation can efficiently remove residual color-protecting agent molecules and micron-sized impurity particles from the surface of carrot pieces, ensuring that the surface cleanliness of the material meets the requirements of subsequent processing. The entire pretreatment process is carried out in a closed, low-temperature environment, with the ambient temperature controlled at 5 degrees Celsius ± 1 degree Celsius and the relative humidity maintained at 85% to minimize the loss of heat-sensitive components.

[0029] Step S3, dynamic pressing and primary filtration, specifically involves feeding the carrot chunks processed in step S2 into a frequency converter-controlled screw press. This press is equipped with a servo motor and a closed-loop control system with pressure sensors, enabling it to execute a segmented pressing strategy under programmed settings. Initially, it operates at 28 rpm and a pressure gradient of 0.6 MPa for 10 minutes to achieve gentle cell rupture and initial juice release. Subsequently, the pressure gradient is linearly increased to 1.2 MPa and maintained for 15 minutes to complete deep pressing. This dynamic pressure control strategy effectively balances juice yield and juice clarity, avoiding excessive cell fragmentation due to instantaneous high pressure, which would increase the burden on subsequent filtration. The pressed juice is transported through stainless steel pipes to a primary filtration device. This device has a built-in 316L stainless steel screen with a pore size of 200 micrometers, and the screen uses a vibration-assisted slag removal design to prevent clogging. After filtration, primary carrot juice is obtained, and its clarity is measured using a transmission light turbidimeter, requiring a minimum of 65%. Clarity is defined as the percentage of light transmittance through a 10 mm optical path at a wavelength of 660 nm. If the clarity falls below the threshold, the system automatically triggers a screen backwashing procedure and records abnormal batches for traceability analysis. This step ensures that the primary juice has a suitable physical state, providing a homogeneous substrate for subsequent enzymatic hydrolysis reactions.

[0030] Step S4, enzymatic hydrolysis and solubilization treatment: Specifically, the primary juice obtained in step S3 is pumped into a jacketed, temperature-controlled enzymatic hydrolysis reactor. A combined pectinase and cellulase enzyme preparation is added to the reactor, with 30 mg / L for pectinase and 20 mg / L for cellulase. The pectinase activity is no less than 200 units / mg, and the cellulase activity is no less than 150 units / mg. The enzyme preparation is stored as a lyophilized powder and prepared as a 10 g / L stock solution with deionized water before use. The reaction conditions are strictly controlled at a temperature of 45°C, a pH of 3.8, and a reaction time of 90 minutes. The pH is monitored in real-time using an online pH electrode and maintained stable by an automatic acid / alkali addition system. To prevent oxidative degradation of carotenoids during enzymatic hydrolysis, high-purity nitrogen is continuously introduced through the top of the reactor to maintain an oxygen partial pressure below 0.5 kPa. The nitrogen flow rate is precisely regulated by a mass flow controller to ensure an inert atmosphere covers the entire liquid surface. During enzymatic hydrolysis, pectinase hydrolyzes the α-1,4-glycosidic bonds of the pectin backbone, while cellulase acts on the β-1,4-glycosidic bonds of cellulose microfibrils, synergistically degrading the residual polysaccharide network of the cell wall, releasing embedded carotenoid crystals, and transferring them from the hydrophobic microdomains to the aqueous continuous phase, significantly improving their dispersibility and accessibility. After the reaction, samples were taken to measure the increase in reducing sugars to verify whether the degree of enzymatic hydrolysis had reached the expected target.

[0031] Step S5, high-pressure homogenization and nano-dispersion: Specifically, the juice obtained from enzymatic hydrolysis in step S4 is preheated to 40 degrees Celsius and then pumped into a three-stage series high-pressure homogenizer. The pressure of the first homogenizing chamber of this homogenizer is set to 30 MPa, the second stage to 50 MPa, and the third stage to 70 MPa, forming a progressively increasing pressure gradient. The working gap is uniformly set to 0.1 mm, and the cooling water system circulates at a flow rate of 12 liters per minute to ensure that the material outlet temperature does not exceed 40 degrees Celsius, preventing the deactivation of heat-sensitive components. The continuous processing flow rate is 1.5 cubic meters per hour, and the equipment is equipped with online viscosity and temperature sensors to monitor the uniformity of the shear field in real time. Under the action of three-stage high pressure, the carotenoid aggregates undergo multiple physical mechanisms such as cavitation effect, turbulent shearing, and collisional fragmentation, and finally the volume average particle size of D[4,3] is reduced to below 380 nanometers, forming a submicron-level stable emulsion system with narrow particle size distribution and an absolute value of Zeta potential greater than 30 millivolts. The particle size of D[4,3] was determined online using a laser particle size analyzer and calculated using Mie scattering theory. The refractive index was set to 1.52 and the absorptivity to 0.1. This nano-dispersion greatly increased the contact area between carotenoids and digestive fluids, creating the necessary conditions for their efficient micellization in subsequent gastrointestinal simulations.

[0032] Step S6, heat activation sterilization and structural fixation, specifically involves immediately feeding the homogenized juice from step S5 into a plate-type instantaneous high-temperature short-time sterilization system. This system consists of a preheating section, a heating section, a holding section, and a cooling section, with 120°C saturated steam as the heating medium. The juice is rapidly heated to 98°C in the heating section and precisely maintained at that temperature for 25 seconds in the holding section, followed by rapid cooling to below 42°C in the cooling section. This heat treatment process effectively inactivates residual pectinase, cellulase, and potentially pathogenic microorganisms, ensuring commercial sterility of the product. More importantly, the instantaneous heat shock at 98°C causes partial denaturation and rearrangement of naturally occurring proteins (such as carotene peroxidase) and polysaccharides (such as pectin and arabinogalactan) at the oil-water interface, forming a dense protein-polysaccharide complex interfacial film. This film significantly enhances the aggregation stability of the droplets through steric hindrance and electrostatic repulsion, preventing Ostwald ripening or flocculation during long-term storage. After sterilization, the juice is transported to a temporary storage tank through a sterile pipeline, awaiting further testing and filling.

[0033] Step S7 involves multi-stage online quality monitoring. Specifically, at four key process nodes—raw material acceptance (corresponding to after step S1), completion of enzymatic hydrolysis (corresponding to after step S4), completion of homogenization (corresponding to after step S5), and pre-sterilization and filling (corresponding to after step S6)—automatic sampling valves and online analysis modules are installed. At each node, a representative 50 ml sample is collected simultaneously, and the following five core indicators are measured: Carotenoid retention rate: The absorbance was measured at a wavelength of 450 nm using a portable UV-Vis spectrophotometer. The current content was calculated using a standard curve and compared with the initial content of the raw material to obtain the retention rate. D[4,3] Particle size distribution: monitored in real time by an online laser particle size analyzer, with data updated every 30 seconds; Oxidation Induction Time (OIT): Using a micro differential scanning calorimeter, 10 mg of sample was placed in an aluminum crucible and heated from 50°C to 200°C at a rate of 10°C per minute. The onset time of the exothermic peak was recorded as the OIT value under an oxygen atmosphere. The OIT of the final product should not be less than 180 minutes. Soluble solids change rate: The percentage change relative to the raw material is calculated by continuously monitoring the °Brix value using an online refractometer; In vitro gastrointestinal absorption simulation: The modified INFUGEST 2.0 protocol was used to simulate three stages of digestion: oral (37°C, pH 6.8, 100 units / mL α-amylase, 5 min), gastric (37°C, pH 3.0, 2000 units / mL pepsin, 2 h), and small intestine (37°C, pH 7.0, pancreatic enzyme and bile salt mixture, 2 h). After digestion, the micelle phase was separated by centrifugation at 10,000 rpm for 10 min. The mass of carotenoids in the micelle phase was determined by high-performance liquid chromatography (HPLC). The absorption rate was calculated using the following formula: The target absorption rate is no less than 42%. All test data are uploaded to the central process control system in real time via industrial Ethernet, with a sampling frequency of no less than once every 10 minutes to ensure the integrity and timeliness of process data.

[0034] Step S8, closed-loop parameter feedback adjustment. Specifically, the central process control system has a built-in multivariate regression model, the expression of which is: Where Y represents the output value of the process parameter to be adjusted, X1 to X n This indicates the degree to which the five core indicators at each detection node deviate from the preset standard value, from β0 to β... n The regression coefficients were obtained through training on over 12,000 historical production data points, with a model prediction accuracy of ≥93%. When any indicator exceeds the preset tolerance range, the system automatically calculates the required compensation and issues an instruction. For example, when the particle size of D[4,3] exceeds 400 nm, the system automatically triggers a recirculation homogenization instruction, returning the material to the homogenization process inlet for secondary processing until the particle size meets the standard; when the predicted in vitro absorption rate is below 40%, the system automatically adds the emulsifying stabilizer xanthan gum to 0.08% before homogenization and extends the nitrogen protection time by 10 minutes to enhance the interfacial film strength and antioxidant capacity. This closed-loop mechanism realizes the transformation from "passive detection" to "active regulation," significantly reducing batch-to-batch differences.

[0035] Step S9, aseptic cold filling and light-protected storage: Specifically, the final juice, confirmed as qualified in step S8, is filled into brown glass bottles sterilized by irradiation with 254 nm ultraviolet light for 30 minutes in a filling room with a cleanliness level of not less than B (ISO 5). The glass bottles have a transmittance of no more than 5% in the 400-500 nm wavelength range, effectively blocking the photo-oxidation of carotenoids by visible light. The relative humidity of the filling environment is controlled at 55% ± 5% to prevent condensation at the bottle neck and the introduction of microorganisms. After capping, the product is immediately conveyed to a 4°C constant temperature warehouse with a light intensity below 50 lux. Under these conditions, the product is allowed to mature for 72 hours, during which the oxygen concentration inside the bottles is monitored periodically using a headspace gas analyzer, and the increase is required to be no more than 15% of the initial value. The maturation process promotes the emulsion system to reach thermodynamic equilibrium, completing the final quality stabilization. The entire method is applicable to industrial production lines of fresh carrot raw materials with a daily processing capacity of not less than 10 tons. The processing time for a single batch is controlled within 4.5 hours. The carotenoid retention rate of the product is stable at over 92%. The D[4,3] particle size is controlled within the range of 350 nm ± 30 nm. The average in vitro gastrointestinal simulated absorption rate reaches 44.6%.

[0036] To further verify the effectiveness of this invention, a specific application example was constructed: a production line processing 12 tons of carrots per day used this method for continuous production for 7 days. Three batches were selected each day, for a total of 21 batches of products, for comprehensive testing. The results showed that the β-carotene retention rate of all batches ranged from 92.3% to 94.1%, the D[4,3] particle size ranged from 328 to 376 nm, the OIT value ranged from 182 to 195 minutes, the in vitro absorption rate remained stable between 42.8% and 45.2%, and the coefficient of variation between batches was less than 3.5%. In contrast, the control group (n=21) using the traditional single-terminal detection process had an absorption rate of only 29.4% to 34.7%, and the D[4,3] particle size fluctuated greatly (450 to 620 nm). This indicates that this invention, through multi-stage detection and closed-loop control, successfully achieved a stable output with high absorption performance.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for processing and controlling highly absorbable carrot juice based on multi-stage quality detection, characterized in that: The specific steps include the following: Step S1, Raw material acceptance and initial physical property testing: Collect fresh carrot raw materials and determine their initial β-carotene content, soluble solids concentration, cellulose enzymatic hydrolysis potential index and surface microbial load; Step S2, Low-temperature color protection pretreatment: Soak the washed and peeled carrot pieces in a compound color protection solution of ascorbic acid and citric acid at 4 degrees Celsius and pH 4.2 for 12 minutes, and then perform ultrasonic-assisted rinsing. Step S3, Dynamic pressing and primary filtration: A variable frequency controlled screw press is used to press in stages at a speed of 28 revolutions per minute and a pressure gradient of 0.6 MPa to 1.2 MPa. After collecting the original juice, it is initially filtered through a stainless steel screen with a pore size of 200 micrometers to obtain primary carrot juice with a clarity of not less than 65%. Step S4, enzymatic hydrolysis and solubilization treatment: Add 30 mg / L of pectinase and 20 mg / L of cellulase to the primary juice and hydrolyze for 90 minutes at 45°C and pH 3.

8. Step S5, High-pressure homogenization and nano-dispersion: The enzymatically hydrolyzed juice is processed by a three-stage high-pressure homogenizer at pressures of 30 MPa, 50 MPa and 70 MPa in sequence to reduce the particle size of carotenoid particles D[4,3] to below 380 nanometers. Step S6, heat activation sterilization and structural shaping: instantaneous high temperature sterilization at 98 degrees Celsius for 25 seconds; Step S7, multi-stage online quality detection: Simultaneously measure five indicators at four nodes: raw material acceptance, end of enzymatic hydrolysis, completion of homogenization and before sterilization and filling, including carotenoid retention rate, D[4,3] particle size distribution, oxidation induction time, soluble solids change rate and in vitro gastrointestinal simulated absorption rate, and upload them to the central process control system. Step S8, closed-loop parameter feedback adjustment: based on the deviation of data at each node, the process compensation coefficient is calculated through a multivariate regression model. When any indicator exceeds the preset tolerance range, the parameters of the next process are automatically adjusted. Step S9, Aseptic Cold Filling and Light-Proof Storage: Fill the final qualified juice into brown glass bottles in an environment with a cleanliness level of not less than B, seal the bottles, and let them stand and mature for 72 hours at 4 degrees Celsius and light intensity of less than 50 lux.

2. The high-absorption carrot juice processing control method based on multi-stage quality detection according to claim 1, characterized in that: The determination criteria include a β-carotene content of not less than 8.5 mg / 100g fresh weight, a soluble solids concentration between 9.0 and 12.0 °Brix, an enzymatic hydrolysis potential index greater than or equal to 75%, and a total surface colony count of less than 3.0 × 10⁻⁶. 4 Each gram of raw material containing CFU enters the subsequent process; the β-carotene content in step S1 is determined by high performance liquid chromatography, with the mobile phase being a methanol-acetonitrile-dichloromethane mixture, the detection wavelength being 450 nm, the linear correlation coefficient R-squared of the standard curve being greater than or equal to 0.9995, and the limit of quantitation being 0.1 mg per 100 g fresh weight.

3. The high-absorption carrot juice processing control method based on multi-stage quality detection according to claim 1, characterized in that: In step S2, the concentration of ascorbic acid is 0.8 g / L, the concentration of citric acid is 1.2 g / L, and the conductivity of the composite color-protecting solution is 1.8 mSiemens per centimeter; the ultrasonic rinsing frequency is 40 kHz, the power density is 0.6 W / mL, and the duration is 3 minutes.

4. The high-absorption carrot juice processing control method based on multi-stage quality detection according to claim 1, characterized in that: In step S4, the pectinase activity is not less than 200 units per milligram, and the cellulase activity is not less than 150 units per milligram; nitrogen gas is continuously introduced during the enzymatic hydrolysis reaction to maintain the oxygen partial pressure below 0.5 kPa.

5. The high-absorption carrot juice processing control method based on multi-stage quality detection according to claim 1, characterized in that: In step S5, the working gap of the high-pressure homogenizer is 0.1 mm, the cooling water flow rate is maintained at 12 liters per minute to control the outlet temperature to not exceed 40 degrees Celsius, and the continuous processing flow rate is 1.5 cubic meters per hour.

6. The high-absorption carrot juice processing control method based on multi-stage quality detection according to claim 1, characterized in that: In step S7, the oxidation induction time is determined by differential scanning calorimetry. The heating rate is 10 degrees Celsius per minute, the starting temperature is 50 degrees Celsius, and the ending temperature is 200 degrees Celsius. The time of the exothermic peak is recorded as the OIT value, and the final product OIT is not less than 180 minutes.

7. The high-absorption carrot juice processing control method based on multi-stage quality detection according to claim 1, characterized in that: In step S7, the in vitro gastrointestinal simulated absorption rate is performed according to the improved INFOGEST2.0 protocol, simulating the digestion stages of the mouth, stomach and small intestine. After digestion, the micelle phase is separated by centrifugation, and the carotenoid content is measured. The absorption rate is calculated as follows: absorption rate = (mass of carotenoids in the micelle phase / mass of total carotenoids) × 100%, and the target absorption rate is not less than 42%.

8. The high-absorption carrot juice processing control method based on multi-stage quality detection according to claim 1, characterized in that: The expression for the multivariate regression model in step S8 is as follows: Where Y represents the output value of the process parameter to be adjusted, and X1 to X... n Indicates the degree to which each detection node deviates from the standard value, β0 to The regression coefficients are obtained by training with historical data, and the model's prediction accuracy is greater than or equal to 93%.

9. The processing control method for highly absorbable carrot juice based on multi-stage quality detection according to claim 1, characterized in that: In step S8, when the particle size of D[4,3] exceeds 400 nanometers, the system automatically triggers a recirculation homogenization command for secondary processing; when the predicted in vitro absorption rate is less than 40%, the amount of xanthan gum added is automatically increased to 0.08% and the nitrogen protection time is extended by 10 minutes.

10. The method for controlling the processing of highly absorbable carrot juice based on multi-stage quality detection according to claim 1, characterized in that: In step S9, the transmittance of the brown glass bottle in the 400 to 500 nanometer wavelength range shall not exceed 5%; the relative humidity of the filling environment shall be controlled at 55% ± 5%; during the curing period, the composition of the headspace gas inside the bottle shall be monitored, and the increase in oxygen concentration shall not exceed 15% of the initial value.

Images