Coffee fermentation-drying continuous production process

Abstract

The invention relates to the technical field of food processing, and discloses a coffee fermentation-drying continuous production process, which is characterized in that slurry which is obtained by previous liquid phase fermentation and contains coffee beans and complete fermentation liquor is directly atomized and sprayed into a fluidized bed reaction system integrated with multiple functions, so that continuous coupling of fermentation and drying processes is realized. A gradient flow field and a material directional recycling loop are constructed in the system, so that the mass transfer and heat transfer efficiency is improved, and energy is recycled; an on-line monitoring and dynamic feedback control unit based on a volatile organic compound spectrum is integrated, so that the flavor evolution is accurately regulated and controlled. And the waste gas circulating gain unit is used for capturing, catalytically converting and reutilizing volatile aromatic substances in the waste gas. According to the invention, a unique composite flavor curing layer can be formed on the surface of the coffee beans in situ. According to the invention, the production process is obviously simplified, the energy consumption is reduced, and the flavor quality and aroma complexity of the coffee product are synchronously improved.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a continuous production process for coffee fermentation and drying. Background Technology

[0002] The final quality of green coffee beans largely depends on their post-harvest processing, which typically includes two core steps: fermentation and drying. In current mainstream processing technologies, fermentation and drying are two independent, non-continuous unit operations. This separate batch processing model not only prolongs the overall production cycle and increases labor and time costs during material handling, but also inherently suffers from inefficiencies in equipment layout and energy consumption.

[0003] More importantly, in order to remove the pectin mucus layer produced after fermentation, traditional processes usually include a washing step between fermentation and drying. However, while removing the mucus, this washing process also discards a large amount of water-soluble flavor precursors (such as sugars, amino acids, and organic acids) that are crucial to the final flavor formation in the fermentation liquid, thus greatly limiting the flavor complexity and body that the coffee beans can ultimately achieve.

[0004] Furthermore, the fermentation process in existing technologies is often difficult to control precisely, and the parameter settings in the drying stage are mostly static, lacking the ability to respond in real time to changes in the biochemical state of the materials during processing. This lack of process control leads to batch-to-batch quality fluctuations in the final product and makes it impossible to proactively intervene and optimize the flavor formation pathway according to specific flavor targets. Therefore, existing technologies generally suffer from technical defects such as lengthy processes, high energy consumption, low utilization of flavor substances, and imprecise process control, failing to maximize the exploration and presentation of the inherent flavor potential of coffee beans while ensuring production efficiency. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a continuous coffee fermentation-drying production process, which solves the problems of low production efficiency, loss of flavor substances, and lack of precise process control caused by the separation of fermentation and drying processes in existing technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a continuous coffee fermentation-drying production process, comprising the following steps: a) Perform a preliminary liquid-phase fermentation on coffee raw materials to obtain a slurry containing coffee beans and fermentation liquid; b) The slurry is fed into a fluidized bed reaction system by atomization spraying; c) Within the fluidized bed reaction system, according to the fermentation process, biochemical reactions and drying aimed at generating aromatic substances are carried out simultaneously by controlling the parameters of the introduced gas. d) Dried coffee beans are continuously produced from the fluidized bed reaction system.

[0007] Preferably, in step c), a gradient flow field is formed in the fluidized bed reaction system to cause the material to self-stratify according to the degree of dryness, and a portion of the material in the intermediate dry state is extracted, mixed with the slurry described in step b), and then atomized and sprayed.

[0008] Preferably, the fermentation process is determined by online monitoring of volatile organic compounds at different spatial locations within the fluidized bed reaction system, and the parameters of the gas are dynamically and regionally adjusted based on the monitoring results.

[0009] Preferably, the parameters of the gas include at least one of temperature, humidity and oxygen concentration.

[0010] Preferably, the method further includes the following steps: e) Treat the exhaust gas discharged from the fluidized bed reaction system and reinject the treated gas into the fluidized bed reaction system as part of the intake gas source.

[0011] Preferably, the processing in step e) specifically includes: The waste gas is selectively condensed to separate volatile organic compounds; The separated volatile organic compounds are subjected to catalytic conversion.

[0012] Preferably, the catalytic conversion is an esterification reaction carried out in a reactor filled with immobilized lipase or molecular sieve catalyst.

[0013] A dried coffee bean comprising a complex flavor-cured layer adhered to the surface of the coffee bean, said complex flavor-cured layer being formed by drying and curing a composition comprising the following components: a) At least one of Pichia pastoris, Saccharomyces cerevisiae and Lactobacillus plantarum, or their metabolites; b) Soluble solids dissolved from the coffee raw material during liquid-phase fermentation; The dried coffee beans have an overall moisture content of 10.0%-12.5%. A continuous coffee fermentation-drying production system includes: a) Fermentation tanks used for preliminary liquid-phase fermentation; b) Fluidized bed reaction system; c) A conveying and spraying device for delivering the slurry in the fermenter into the fluidized bed reaction system by atomization; d) A discharge device for continuously discharging dried coffee beans from the fluidized bed reaction system.

[0014] Preferred options also include: An exhaust gas recirculation gain unit is connected to the exhaust gas outlet and inlet of the fluidized bed reaction system. The exhaust gas recirculation gain unit includes a selective condenser for separating volatile organic compounds and a catalytic reactor for catalytically converting the separated volatile organic compounds.

[0015] This invention provides a continuous coffee fermentation-drying production process. It has the following beneficial effects: 1. This invention couples the fermentation and drying processes within a single fluidized bed reaction system and employs continuous operation, completely eliminating the need for multiple independent unit operations such as solid-liquid separation and material transfer required in traditional processes. This not only significantly shortens the total time from fermentation completion to obtaining the dried product but also reduces equipment footprint and potential material loss, thereby simplifying the production process and improving efficiency.

[0016] 2. This invention employs a technique of directly atomizing and drying the complete slurry containing the fermentation liquid. This allows non-volatile or semi-volatile flavor precursors such as alcohols, acids, and sugars dissolved in the fermentation liquid to be concentrated and solidified along with microbial metabolites during the drying process, forming a unique composite flavor solidification layer on the surface of the coffee beans. This contrasts sharply with the traditional process where solid-liquid separation leads to the loss of a large amount of water-soluble flavor precursors, thereby enhancing the flavor richness and complexity of the final product.

[0017] 3. This invention constructs a gradient flow field within the fluidized bed and establishes a directional recirculation loop for intermediate materials. This allows a portion of the semi-dry material, already at a certain temperature, to be returned to the feed end. This returned material not only directly transfers its heat energy to the newly entering low-temperature slurry, achieving efficient internal energy circulation, but also, as a dispersing carrier, improves the atomization effect of the fresh slurry, effectively reducing the risk of nozzle clogging and ensuring the long-term stable operation of the entire continuous process. Attached Figure Description

[0018] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of the process modules of the present invention. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: Please see the appendix Figure 1 - Appendix Figure 2 This invention provides a continuous coffee fermentation-drying production process, comprising: This embodiment aims to fully demonstrate a process flow of the present invention that includes all the core technical features, and to prepare sample S1.

[0021] (1) Raw material preparation Coffee Raw Materials: Fresh, ripe coffee cherries of the small-bean variety are selected from the Pu'er City region of Yunnan Province, China. The cherries are transported and processed within 24 hours of harvesting. A mechanical peeling machine is used to remove the skin and most of the pulp from the coffee cherries, yielding coffee beans with the pectin layer intact.

[0022] Microbial inoculant: A compound microbial inoculant was prepared by physically mixing freeze-dried powders of Pichia pastoris (strain number CICC 1768), Saccharomyces cerevisiae (strain number CICC 1251), and Lactobacillus plantarum (strain number CICC 6032) purchased from the China Industrial Microbial Culture Collection Center at a mass ratio of 1:1:1. The total viable count was not less than 1×10⁻⁶. 10 CFU / g.

[0023] Process gases and catalysts: Nitrogen (purity ≥99.999%, CAS No.: 7727-37-9); Oxygen (food grade, CAS No.: 7782-44-7); Immobilized lipase (derived from Candida antarcticis lipase B, purchased from Novozymes (China) Biotechnology Co., Ltd.).

[0024] (2) Pre-liquid phase fermentation 100 kg of coffee beans with a pectin layer were transferred into a 500 L stainless steel fermentation tank equipped with a jacketed temperature control and low-shear stirring device. 200 kg of reverse osmosis purified water was added to achieve a solid-liquid ratio of 1:2. After heating to 22°C, 0.1 kg (0.1% w / w of the coffee bean wet weight) of the prepared compound microbial inoculant was added. The tank was sealed, and nitrogen gas was introduced into the top space to expel most of the air, establishing an anaerobic environment. The stirrer was set to 50 rpm, stirring for 10 minutes every 3 hours. Fermentation was carried out at a constant temperature of 22°C for 48 hours to obtain a slurry containing coffee beans and fermentation liquid.

[0025] (3) Coupled fermentation-drying Slurry delivery and atomization: Start the screw pump to pump the slurry obtained in step (2) to the feed line of the fluidized bed coupled reaction system at a flow rate of 10 L / min. In this line, the slurry is mixed online with the semi-dry material from the subsequent directional recycling step at a mass ratio of 0.2:1 (recycled material to fresh slurry). The mixed slurry enters the dual-fluid atomizing injector at the top of the tower, using nitrogen gas at a pressure of 0.3 MPa as the atomizing gas to uniformly spray the slurry into the fluidized bed tower.

[0026] Fluidized bed operation: A mixture of nitrogen and oxygen is introduced from the bottom of the column as the fluidizing medium. A multi-zone gas distribution plate maintains an apparent gas velocity of 1.5 m / s in the central zone and 1.1 m / s in the outer zones. The total inlet gas temperature is set at 95℃, and the initial inlet oxygen volume concentration is 2.0%. By adjusting the inlet parameters, the macroscopic average temperature of the material in the fluidized bed is maintained at 55℃. The feed and discharge rates are controlled to ensure an average residence time of 60 minutes for the material within the bed.

[0027] Online monitoring and feedback control: Online monitoring is performed using proton transfer reaction mass spectrometers (PTR-MS) connected to probes located at the top, middle, and bottom of the column. When the signal intensity of ethyl acetate (m / z 61) in the upper region of the column reaches its peak and begins to stabilize, and the signal intensity of ethanol (m / z 47) shows a significant decreasing trend, the central control system automatically increases the oxygen concentration of the gas supplied to the peripheral region from 2.0% to 3.5%, while simultaneously reducing the oxygen concentration of the gas supplied to the central region to 1.0%.

[0028] Directional recirculation: Semi-dry material is continuously extracted from the side extraction port in the middle section of the tower at a rate equivalent to 10% / min of the total material mass of the bed, and then sent back to the feed pipeline through an external insulated pipe.

[0029] (4) Exhaust gas recirculation gain The exhaust gas discharged from the top of the tower is introduced into the exhaust gas recirculation gain unit. It first passes through a two-stage condensation system. The first stage condensation temperature is controlled at 25°C to separate most of the water vapor, and the second stage condensation temperature is controlled at 5°C to capture and concentrate VOCs. The concentrated VOCs gas is then introduced into a tubular reactor filled with Novozym® 435 immobilized lipase, and the reactor temperature is maintained at 60°C. The catalytically converted gas is mixed with freshly regulated gas and injected as the inlet gas source into the bottom of the fluidized bed. This recirculated gas flow accounts for 40% of the total inlet volumetric flow rate.

[0030] (5) Continuous production of finished products The dried coffee beans are continuously discharged through a star-shaped discharge valve at the bottom of the tower. When the moisture content is measured to be 11.5% by an online moisture meter, this is used as the target for discharge control. The discharged coffee beans immediately enter a nitrogen-protected cooling conveyor system, where they are rapidly cooled to below 30°C to obtain the final product, designated as sample S1.

[0031] Example 2: This embodiment aims to illustrate that by adjusting key parameters in the process of this invention, the flavor characteristics of the final product can be directionally shaped. This embodiment aims to enhance the floral and fruity aroma of the final product, and samples S2 were prepared accordingly.

[0032] The equipment, raw material specifications, and most of the operating steps used in this embodiment are the same as in Embodiment 1, with the following differences: (1) Adjustment of compound microbial agents To focus on generating more esters and their precursors, the formulation of the compound microbial agent was adjusted. Freeze-dried powders of Pichia pastoris (strain number CICC 1768), Saccharomyces cerevisiae (strain number CICC 1251), and Lactobacillus plantarum (strain number CICC6032) were physically mixed in a mass ratio of 3:1:1 to prepare a compound microbial agent focused on aroma production.

[0033] (2) Adjustment of preceding liquid-phase fermentation conditions To adapt to the adjusted inoculum ratio, the constant temperature of the preceding liquid-phase fermentation was adjusted to 20°C, and the fermentation time was extended to 60 hours to promote the full accumulation of esterification precursors such as alcohols and organic acids.

[0034] (3) Adjustment of online monitoring and feedback control strategies The feedback control strategy was adjusted to extend and enhance the esterification reaction window. Specifically, when the online monitoring system detected that the concentrations of ethanol (m / z 47) and acetic acid (whose mass spectrometry signals could be monitored) in the upper region of the column had reached a stable plateau, the central control system precisely controlled and maintained the oxygen concentration supplied to that region at 2.5% for 25 minutes. After this phase, the inlet oxygen concentration was reduced to below 0.5% to complete the final drying and flavor curing process.

[0035] (4) Adjustment of catalyst in exhaust gas recirculation gain unit To adapt to different catalytic conversion targets, the packing material of the tubular reactor in the exhaust gas recirculation gain unit was replaced with ZSM-5 molecular sieve catalyst (silicon-to-aluminum ratio 38, strip-shaped, purchased from Nankai University Catalyst Co., Ltd.). Simultaneously, the operating temperature of the catalytic reactor was set to 80℃.

[0036] Except for the adjustments mentioned above, all other operational steps, including slurry delivery, atomization, fluidized bed gradient flow field, directional recirculation ratio, and the target moisture content of the final product, remain consistent with those in Example 1. The final product is designated as Sample S2.

[0037] Comparative Example 1: The difference compared to Example 1 is as follows: After completing the preliminary liquid-phase fermentation in step (2), no subsequent coupled fermentation-drying is performed. Instead, a horizontal screw centrifuge is used to separate the fermentation slurry into solid and liquid components, and the separated liquid portion (fermentation liquid) is discarded. The separated wet coffee beans are fed into a conventional hot air fluidized bed dryer and dried at a constant inlet air temperature of 80°C until the material moisture content reaches 11.5%. During this process, the drying exhaust gas is directly discharged.

[0038] The remaining steps, such as raw material preparation and preliminary liquid-phase fermentation, are the same as in Example 1. The final product is designated as sample CS1.

[0039] Comparative Example 2: The difference compared to Example 1 is as follows: After completing the preliminary liquid-phase fermentation in step (2), a horizontal screw centrifuge was used for solid-liquid separation, and the liquid portion was discarded. The separated wet coffee beans were directly added to the same fluidized bed reaction system as in Example 1 for drying (this process did not involve atomization). During the drying process, the exhaust gas recirculation gain unit was not activated, and all exhaust gas was directly discharged from the top of the tower. The drying gas parameters (inlet temperature 95°C, oxygen concentration 2.0%) remained constant throughout the process.

[0040] The remaining steps, such as raw material preparation and preliminary liquid-phase fermentation, are the same as in Example 1. The final product is designated as sample CS2.

[0041] Comparative Example 3: The difference compared to Example 1 is as follows: During the coupled fermentation-drying process in step (3), the lateral extraction port located in the middle section of the tower is closed, meaning that directional recirculation of the semi-dry material is not performed. Simultaneously, the online monitoring and feedback control system is not activated, and the fluidized bed's inlet parameters (inlet temperature 95°C, oxygen volume concentration 2.0%) remain constant throughout the entire 60-minute drying cycle.

[0042] All other steps, including pre-fermentation, slurry atomization and spraying, exhaust gas recirculation gain, and the target moisture content of the final product, were the same as in Example 1. The final product was designated as Sample CS3.

[0043] Test Example 1: This test case aims to objectively evaluate and compare the flavor quality of the coffee bean samples prepared by Examples 1-2 and Comparative Examples 1-3 using standardized sensory evaluation methods.

[0044] Experimental steps: Sample roasting and preparation: Take 500g each of sample S1 obtained in Example 1, sample S2 obtained in Example 2, sample CS1 obtained in Comparative Example 1, sample CS2 obtained in Comparative Example 2, and sample CS3 obtained in Comparative Example 3. Use a ProbatBRZ-02 laboratory sample roaster to roast each sample to a medium roast level with an Agtron value of 58±2. After roasting, seal and let the samples stand at room temperature (22℃) and 55% relative humidity for 72 hours to allow for full flavor development and stability.

[0045] Evaluation Panel and Procedures: A sensory evaluation panel of 8 Q-Graders certified by the Specialty Coffee Association of America (SCA) was organized. The evaluation process strictly followed the cupping procedures published by the SCA and employed a double-blind method to eliminate subjective bias. The specific procedure was as follows: 11.0g of roasted beans were weighed, ground on-site, and placed in a cupping bowl for dry aroma evaluation; 200mL of hot water at 93°C was poured into the bowl, and after standing for 4 minutes, the wet aroma was evaluated; then the grounds were broken and the surface coffee powder was removed; the coffee was then cooled to approximately 70°C before tasting.

[0046] Data Collection and Processing: Evaluators scored each sample according to the SCA cupping form, evaluating nine aspects: dry / wet aroma, flavor, finish, acidity, body, consistency, balance, cleanliness, and sweetness (each aspect is out of 10 points), and provided a comprehensive score. The arithmetic mean of the scores from the eight evaluators was taken as the final score for that aspect.

[0047] Experimental data: Table 1: Sensory quality evaluation results of each sample The sensory evaluation data in Table 1 show that the overall scores and multiple key sub-scores of samples S1 and S2 are significantly higher than those of the comparative samples CS1, CS2, and CS3. The mechanism behind this result lies in the process employed in this invention, which involves the overall atomization of the complete slurry containing coffee beans and fermentation liquid. During the rapid drying process, non-volatile flavor precursors such as sugars, organic acids, amino acids, and microbial metabolites originally dissolved in the fermentation liquid are concentrated and adhered to the surface of the coffee beans, forming a complex flavor solidification layer. This directly results in samples S1 and S2 scoring significantly higher in terms of body, sweetness, and aftertaste than CS1 and CS2, which lost these substances through solid-liquid separation.

[0048] The comparison between samples S1 and CS3 clearly reveals the role of online monitoring and dynamic feedback control in the precise shaping of flavor. Although sample CS3 also used slurry atomization, under constant drying conditions, complex biochemical reactions (such as esterification and Maillard reactions) could not proceed within their respective optimal windows, resulting in uneven flavor development and consequently lower balance and consistency scores. In contrast, sample S1, through online monitoring of volatile organic compounds, achieved dynamic and regional control of atmospheric parameters in different areas of the bed, creating a suitable microenvironment for different reaction stages, thus achieving a more balanced and layered flavor, and consequently, a higher balance score.

[0049] Data from sample S2 further confirms the controllability and flavor-oriented shaping capabilities of this process system. By adjusting the microbial inoculant ratio and matching corresponding fermentation and drying control strategies, sample S2 achieved higher scores than sample S1 in the two core aroma indicators of dry / wet aroma and flavor, exhibiting more pronounced floral and fruity aroma characteristics. This indicates that the technical solution of this invention is not a fixed process, but a technical platform capable of precisely intervening in and optimizing the aromatic characteristics of the final product by adjusting process parameters, thereby meeting diverse product demands.

[0050] Test Example 2: This test example aims to quantitatively analyze the key volatile flavor compounds in the samples prepared in Examples 1-2 and Comparative Examples 1-3 using gas chromatography-mass spectrometry (GC-MS), providing chemical data support for the sensory evaluation results of Test Example 1.

[0051] (1) Experimental Procedure Sample pretreatment: Take samples S1, S2, CS1, CS2, and CS3 from Test Example 1, which have been roasted and allowed to stand. Grind each sample into powder using a cryogenic grinder under liquid nitrogen. Accurately weigh 2.0 g of coffee powder and quickly place it into a 20 mL headspace vial. Add 10 μL of an ethanol solution of 50 μg / mL 2-octanol (CAS No.: 123-96-6) as an internal standard. Seal the vial.

[0052] Headspace solid-phase microextraction (HS-SPME): The sample vial was placed in a constant temperature water bath and equilibrated at 60°C for 15 minutes. Subsequently, a 50 / 30 μm DVB / CAR / PDMS extraction head was manually inserted into the headspace portion of the sample vial, and adsorption extraction was performed at 60°C for 40 minutes.

[0053] Gas chromatography-mass spectrometry (GC-MS) analysis: After extraction, immediately insert the extraction head into the injection port of the gas chromatograph and desorb at 250℃ for 5 minutes.

[0054] GC conditions: The column was a DB-5MS capillary column (30 m × 0.25 mm × 0.25 μm); the carrier gas was high-purity helium, with a flow rate of 1.0 mL / min; the temperature program was as follows: initial temperature 40℃, hold for 3 minutes, increase to 150℃ at a rate of 5℃ / min, then increase to 230℃ at a rate of 10℃ / min, and hold for 5 minutes.

[0055] MS conditions: Electron impact (EI) source with electron energy 70 eV; ion source temperature 230℃; mass spectrometry scan range m / z 35-450.

[0056] Quantitative analysis: Quantification was performed using the external standard method combined with internal standard correction. A series of standard solutions with varying concentrations were prepared using commercial standards, and the determinations were performed according to the method described above to plot a standard curve. The concentration of each compound was calculated from the standard curve based on the ratio of the peak area of ​​the target compound to the peak area of ​​the internal standard in each sample.

[0057] Table 2: Results of determination of key flavor compounds in samples from different processes (μg / kg) The quantitative analysis data in Table 2 show that the content of ester compounds (ethyl acetate and isoamyl acetate) positively correlated with floral and fruity aromas in samples S1 and S2 is significantly higher than that in comparative samples CS1 and CS2. The fundamental reason for this difference lies in the different process flows. The processes in S1 and S2 preserve the complete fermentation slurry, allowing water-soluble ester precursors such as alcohols and organic acids produced by microbial metabolism in the fermentation broth to persist and react in the subsequent coupled drying stage. In contrast, in the processes of CS1 and CS2, the solid-liquid separation step removes these key precursors along with the liquid portion, fundamentally limiting the formation pathway of esters and resulting in their lower final content.

[0058] Comparing the chemical data of S1 and CS3, it can be observed that although both use full slurry processing, the content of esters and diacetyl in S1 is significantly higher than that in CS3. This phenomenon is attributed to the online monitoring and dynamic feedback control system integrated into the S1 process. This system can provide a more suitable gaseous environment (e.g., precisely controlled oxygen concentration and temperature) for key biochemical reaction stages such as esterification based on real-time spectra of volatile organic compounds, thereby improving the conversion efficiency of the reaction. The CS3 process, lacking this dynamic control mechanism, operates under constant gas parameters, and its reaction conditions cannot be maintained at the optimal state throughout the entire process cycle, resulting in lower product yields.

[0059] The further increase in ethyl acetate and isoamyl acetate content in sample S2 compared to S1 verifies the controllability of this technical solution. By adjusting the initial microbial ratio to enrich yeasts with stronger ester-producing capabilities and matching corresponding online control strategies, the substrate concentration and reaction conditions of the esterification reaction are shifted in a direction more favorable to the formation of the target product. This indicates that the system and method disclosed in this invention provide a technical means to precisely control process parameters to directionally change the chemical composition of the final product, thereby shaping its specific flavor characteristics.

[0060] Test Example 3: This test case aims to objectively quantify and compare the differences in time and energy consumption between the different process flows represented by Example 1, Comparative Example 1, and Comparative Example 3.

[0061] Experimental steps: Time efficiency determination: For each process (Example 1, Comparative Example 1, Comparative Example 3), the time was measured in batches of 100 kg of wet soybeans. The starting point of the timekeeping was uniformly set to the end of the preceding liquid-phase fermentation. The ending point of the timekeeping was the moment when the final dried product with a moisture content of 11.5% was obtained. For Comparative Example 1, the total processing time includes the solid-liquid separation operation time and the subsequent independent drying time. The total processing time consumed by each process step was recorded.

[0062] Energy Consumption Measurement: During the drying-related operations of each process flow, industrial-grade electricity meters are used to monitor and accumulate the total input electrical power of all energy-consuming equipment involved in this stage (including but not limited to: slurry pumps, gas compressors, electric heaters, fluidized bed fans, centrifuges, discharge valves, and control systems) in real time. The total electrical energy consumed for each process from the start to the end of the timing period is measured and recorded. The total electricity consumption is divided by the amount of raw material processed (100 kg of wet beans) to calculate the unit energy consumption.

[0063] Data recording: The total processing time and unit energy consumption data obtained from the measurements will be recorded and organized for subsequent comparative analysis.

[0064] Table 3: Comparison of Key Efficiency Indicators for Different Process Flows Table 3 clearly shows that, compared with the traditional process represented by Comparative Example CS1, the process used in Example 1 significantly reduces both the total processing time and unit energy consumption. This is mainly due to the fundamental differences in their process structures. By coupling the fermentation and drying processes within a single, continuously operating fluidized bed reaction system, this invention eliminates multiple independent unit operations such as solid-liquid separation and material transfer required in traditional processes. This physically shortens the process path, avoids waiting time between process transitions, and directly leads to a reduction in processing time and a decrease in additional energy consumption caused by equipment start-up and shutdown and material transportation.

[0065] The comparison of data from Example 1 and Comparative Example CS3 provides isolated evidence of the technical effectiveness of the internal material-oriented recycling loop. Both samples have similar processing times, but the unit energy consumption of Sample S1 is significantly lower than that of Sample CS3. The mechanism lies in the fact that in the process of Sample S1, the semi-dry material extracted from the middle section of the fluidized bed carries a large amount of heat energy. When it is re-transported to the feed end and mixed with the low-temperature slurry, direct heat exchange occurs, thereby recovering some of the heat that would otherwise be discharged with the product. This internal heat energy recycling mechanism effectively reduces the total heat supplied from the outside to maintain the thermal balance of the entire system, thus its unit energy consumption is significantly lower than that of Sample CS3, which lacks this heat recovery mechanism.

[0066] Comprehensive analysis shows that this technical solution improves energy efficiency and time efficiency through two different mechanisms. First, by integrating multiple production steps into a continuous unit, the macroscopic process is simplified, which is the main reason for the improved time efficiency. Second, by establishing a directional heat energy circulation loop within the unit, energy recovery and reuse are achieved at the microscopic level, which is a key factor in reducing unit energy consumption. This efficiency improvement was achieved while maintaining the product quality shown in Test Example 1, indicating that this process has dual advantages in terms of economy and product performance.

[0067] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A continuous coffee fermentation-drying production process, characterized in that, Includes the following steps: a) Perform a preliminary liquid-phase fermentation on coffee raw materials to obtain a slurry containing coffee beans and fermentation liquid; b) The slurry is fed into a fluidized bed reaction system by atomization spraying; c) Within the fluidized bed reaction system, according to the fermentation process, biochemical reactions and drying aimed at generating aromatic substances are carried out simultaneously by controlling the parameters of the introduced gas. d) Dried coffee beans are continuously produced from the fluidized bed reaction system.

2. The continuous coffee fermentation-drying production process according to claim 1, characterized in that, In step c), a gradient flow field is formed in the fluidized bed reaction system to cause the material to self-stratify according to its degree of dryness, and a portion of the material in the intermediate dry state is extracted, mixed with the slurry described in step b), and then atomized and sprayed.

3. The continuous coffee fermentation-drying production process according to claim 1, characterized in that, The fermentation process is determined by online monitoring of volatile organic compounds at different spatial locations within the fluidized bed reaction system, and the parameters of the gas are dynamically and regionally adjusted based on the monitoring results.

4. The continuous coffee fermentation-drying production process according to claim 3, characterized in that, The parameters of the gas include at least one of temperature, humidity and oxygen concentration.

5. The continuous coffee fermentation-drying production process according to claim 1, characterized in that, Further steps include: e) Treat the exhaust gas discharged from the fluidized bed reaction system and reinject the treated gas into the fluidized bed reaction system as part of the intake gas source.

6. The continuous coffee fermentation-drying production process according to claim 5, characterized in that, The processing in step e) specifically includes: The waste gas is selectively condensed to separate volatile organic compounds; The separated volatile organic compounds are subjected to catalytic conversion.

7. The continuous coffee fermentation-drying production process according to claim 6, characterized in that, The catalytic conversion is an esterification reaction carried out in a reactor filled with immobilized lipase or molecular sieve catalyst.

8. A dried coffee bean, applied to the production process described in any one of claims 1-7, characterized in that, It comprises a complex flavor-curing layer attached to the surface of coffee beans, said complex flavor-curing layer being formed by drying and curing a composition comprising the following components: a) At least one of Pichia pastoris, Saccharomyces cerevisiae and Lactobacillus plantarum, or their metabolites; b) Soluble solids dissolved from the coffee raw material during liquid-phase fermentation; The dried coffee beans have an overall moisture content of 10.0%-12.5%.

9. A continuous coffee fermentation-drying production system for performing the process of claim 1, characterized in that, include: a) Fermentation tanks used for preliminary liquid-phase fermentation; b) Fluidized bed reaction system; c) A conveying and spraying device for delivering the slurry in the fermenter into the fluidized bed reaction system by atomization; d) A discharge device for continuously discharging dried coffee beans from the fluidized bed reaction system.

10. The continuous coffee fermentation-drying production system according to claim 9, characterized in that, Also includes: An exhaust gas recirculation gain unit is connected to the exhaust gas outlet and inlet of the fluidized bed reaction system. The exhaust gas recirculation gain unit includes a selective condenser for separating volatile organic compounds and a catalytic reactor for catalytically converting the separated volatile organic compounds.

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