Gradient composite aging method for improving structure and flavor of mango wine

Abstract

The invention relates to a gradient composite aging method for improving the structure and flavor of mango wine, and belongs to the technical field of fruit wine brewing. The method comprises the following steps: by taking mango raw wine with specific physicochemical indexes as base wine, mixing oak chips and mango wood, then carrying out synergistic pretreatment including alkaline complex liquid soaking, steaming and gradient heating baking, and then sequentially ageing the base wine in three stages: in the first stage, inoculating a specific strain, and carrying out sealed fermentation so as to reduce the content of malic acid and diacetyl; in the second stage, pre-treated oak chips are added for low-temperature impregnation to enhance the wine body structure, and in the third stage, pre-treated mango wood is added for continuous impregnation to realize flavor fusion. The method is mainly used for brewing the high-quality mango wine, the structural feeling, complexity and mellowness of a wine body can be remarkably improved, and meanwhile, the unique fruity flavor of mangoes is perfectly reserved and sublimated.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and more specifically to a gradient compound aging method for improving the structure and flavor of mango wine. Background Technology

[0002] Mango wine is a fruit wine made primarily from mangoes. It boasts a bright color and is rich in the unique aromas of tropical fruits, possessing significant development potential and market value. However, compared to traditional wines, mango wine often faces challenges such as a relatively simple structure, insufficient flavor complexity, and a less full-bodied and harmonious taste. This is mainly due to the specific organic acid composition, aroma precursors, and characteristics of the fermentation products in its raw materials.

[0003] To enhance the structure and flavor of fruit wines, the wine industry often draws on winemaking experience, incorporating oak aging techniques. Through the extraction and reaction of lignin, tannins, lactones, and aromatic compounds from oak in the wine, more complex aromas, a smoother mouthfeel, and a more stable structure can be imparted. However, directly applying traditional oak aging techniques to mango wine often creates new problems. For example, the strong vanilla, smoky, and toasty aromas derived from oak can easily mask the fresh and unique tropical fruit aromas of mango itself, resulting in flavor clashes rather than harmony. Furthermore, improper oak treatment or the amount added may exacerbate the original astringency of the mango wine or introduce unpleasant woody tannins, making the taste rough.

[0004] While existing technologies have attempted to adapt fruit wines by using oak products with different toasting levels or shortening aging times, they have not yet effectively solved the fundamental problem of the inability to harmoniously integrate the flavors of imported oak with the flavors of the native mango base wine. Simply reducing oak contact, while preserving more fruit aromas, fails to achieve the initial goal of enhancing the wine's structure and complexity. Therefore, designing an aging method specifically for mango wine that effectively utilizes the beneficial components of oak and other woods to strengthen its structure and flavor profile, while maximally respecting, preserving, and elevating the varietal aromas of the mango itself—achieving a "reinforcement without overpowering" effect—has become a critical technological bottleneck that urgently needs to be overcome in this field.

[0005] Furthermore, existing technologies for microbial post-fermentation and multi-stage processing involved in the aging process mostly focus on single systems such as wine, lacking a systematic and gradient process design for mango wine as a specific base wine and the synergistic effects of various woods (including the introduction of related fruit trees). This makes it difficult to accurately guide and control the evolution of flavor compounds during the aging process. There is also room for improvement in clarification efficiency, flavor retention, and automation levels in the post-aging stabilization and processing stages. Summary of the Invention

[0006] One object of the present invention is to address at least the aforementioned deficiencies and provide at least the advantages described below. The term "lightly or moderately roasted oak chips" as used herein refers to oak chips that have undergone a heat treatment designed to impart specific flavors, wherein light roasting is performed at a final temperature of 120°C to 150°C for 1 to 2 hours. After this treatment, the oak chips are light yellow to light brown, primarily developing fresh flavors similar to vanilla, coconut, and fresh wood, with relatively mild tannin extraction. Moderate roasting is performed at a final temperature of 150°C to 180°C for 2 to 3.5 hours. After this treatment, the oak chips are medium brown, primarily developing flavors of toast, caramel, almond, and a touch of spice, with a stronger tannin structure and a richer aroma. Lightly or moderately roasted oak chips can be commercially available products or can be prepared at home using the parameters described above. This pretreatment aims to initially impart specific flavor profiles to the oak chips and to make their structure more suitable for subsequent synergistic pretreatment steps (including immersion in an alkaline compound solution, steaming, and gradient roasting). It should be noted that this definition of "light / medium roasting" and the "gradient temperature roasting" in the subsequent co-processing steps are two independent and sequentially performed different process stages. In this invention, "mango tree wood" specifically refers to wood belonging to the same species (scientific name: Mangifera indica, i.e., mango) as the mango raw material used for brewing, and it can be any cultivar of that species.

[0007] To achieve these objectives and other advantages of the present invention, a gradient aging method for enhancing the structure and flavor of mango wine is provided, comprising: using mango wine with an alcohol content of 9.5-10.5% vol, a malic acid content of 3.0-6.0 g / L, and a pH of 3.4-3.6 after primary fermentation as the base wine; and preparing wood materials for aging, including lightly or moderately roasted American white oak or French oak chips, and mango tree wood of the same species as or the same species as the winemaking raw materials; firstly, synergistic pretreatment of the wood materials: mixing oak chips and mango tree wood at a weight ratio of 1:1-3, placing them in a 1-3% sodium bicarbonate and 0.5-1.5% sodium citrate aqueous solution with a solid-liquid ratio of 1:5-10, and soaking at 60-80°C for 2-4 hours; draining until there is no obvious flowing water on the surface, and then aging at 0.12-0.15... Steam for 20-40 minutes at saturated steam pressure of MPa; then bake at a gradient temperature of 80-100℃ for 1-2 hours, then increase to 120-150℃ for 0.5-2 hours; after pretreatment, separate the two types of wood; then, age the base wine in the following three stages: First stage: Place the mango base wine that has completed primary fermentation in a stainless steel tank, add *Schizophyllum commune* and *Schizophyllum esculentum* for fermentation; before inoculation, *Schizophyllum commune* and *Schizophyllum esculentum* should have been adapted to the mango wine substrate environment of 9.5-10.5% vol and pH 3.4-3.6, and ferment under airtight conditions at 18-22℃; when the malic acid content in the wine drops below 0.5 g / L and the diacetyl content drops below 2 mg / L, this stage is considered complete, and the first fruit wine is obtained; the inoculation amount of *Schizophyllum commune* is 1×10 6 -5×10 6 CFU / mL, the inoculum size of *Schizosaccharomyces cerevisiae* was 1×10⁻⁶. 4 -5×10 5 CFU / mL; Second stage: Add the pretreated oak chips to the first fruit wine at a rate of 2-8 g / L and macerate at 12-16℃ for 30-60 days to obtain the second fruit wine; Third stage: Add the pretreated mango wood to the second fruit wine at a rate of 1-10 g / L and continue to macerate for 15-90 days.

[0008] Preferably, the gradient compound aging method for improving the structure and flavor of mango wine of the present invention includes a controlled micro-oxygen treatment based on a mass balance model during the third stage, specifically including: a) Model establishment: Before the start of the third stage, the cumulative oxygen consumption per unit mass of mango wood during the 15-90 day maceration period is determined by small-scale testing as M; b) Calculation of total oxygen demand: Based on the total amount of mango wood added in the third stage and the total volume of wine V, the total oxygen demand Q = M × total mass of wood is calculated; c) The total oxygen demand Q is divided into n equal parts to form an n-time pulse oxygen supply plan; during each oxygen supply, sterile filtered compressed air is used for ventilation through an aeration stone located at the bottom of the container, with a ventilation rate of 0.1 to 0.3 times the volume of gas per unit volume of wine per minute, and a single ventilation duration of 1 to 3 minutes; where n is the integer obtained by dividing the number of maceration days by a selected value in the range of 5 to 10 and then rounding up; d) Simplified Verification and Adjustment: At the beginning, middle, and end of the third stage, use a portable dissolved oxygen meter to measure the dissolved oxygen concentration of the wine. In the middle stage, if the results of three consecutive measurements are all below 0.2 mg / L, increase the ventilation time by 10%-30% in subsequent pulses. If the dissolved oxygen concentration is above 0.8 mg / L in any measurement or at the end, stop the subsequent pulse oxygen supply plan and record the actual cumulative oxygen supply for this aging cycle. This cumulative oxygen supply will be used to calibrate and optimize the value of the cumulative oxygen consumption M per unit mass of mango wood. The interval between each measurement shall not exceed 5 days.

[0009] Preferably, the gradient compound aging method for improving the structure and flavor of mango wine of the present invention further includes a non-animal-derived compound stabilization and filtration step after all aging stages are completed: The temperature of the wine after the third stage of maceration is adjusted to 12-16°C, and 200-500 mg / L of sodium bentonite is added to the wine. This bentonite has been pre-hydrated and activated in 10 times its weight of deionized water at 35-40°C for 24 hours. After addition, the wine is stirred at 20-30 rpm for 30 minutes, and then allowed to stand at the same temperature for 5-7 days to obtain the first supernatant. The temperature of the first supernatant is adjusted to 14-18°C, and a chitosan derivative clarifying agent is added at an addition rate of 50-300 mg / L, at a concentration of 40-60 mg / L. Stir at rpm for 15 minutes, then switch to low speed stirring at 10-20 rpm for 2 hours. After that, let it stand at 14-18℃ for 3-5 days to obtain the second supernatant. The second supernatant is then cross-flow filtered at 8-12℃ using a polyvinylidene fluoride membrane with a pore size of 0.2-0.45μm. The system operating pressure is controlled at 1.0-2.0 bar, and the membrane surface flow rate is maintained at 2-4 m / s. The chitosan derivative clarifying agent is carboxymethyl chitosan or quaternized chitosan with a number average molecular weight of 50,000-500,000 Daltons and a degree of deacetylation ≥85%.

[0010] Preferably, the gradient composite aging method for improving the structure and flavor of mango wine of the present invention employs a staged variable parameter operation in the cross-flow membrane filtration step, specifically including: maintaining the membrane surface flow rate at 3.5-4.0 m / s and controlling the operating pressure at the lower limit of 1.0-1.5 bar within the first 10-20 minutes of filtration; when the turbidity of the permeate obtained from the membrane module outlet drops below 5 NTU, adjusting the membrane surface flow rate to 2.5-3.5 m / s and slowly increasing the operating pressure to 1.5-2.0 bar and maintaining it stable; when the remaining wine is 8-12% of the total volume, reducing the membrane surface flow rate to 2.0-2.5 m / s, while further reducing the wine temperature to 6-10°C, and immediately using food-grade inert gas at a temperature of 6-10°C, a pressure of 0.5-1.5 bar, and a flow rate of 50-150 L / min to top-treat the circulation pipeline, completely recovering the residual wine in the system.

[0011] Preferably, the gradient compound aging method of the present invention for improving the structure and flavor of mango wine includes an inert gas top-liquid treatment specifically comprising: using food-grade nitrogen or argon gas at the same temperature of 6-10°C, continuously injecting it from the wine inlet of the filtration system at a constant pressure of 0.5-1.5 bar and a flow rate of 50-150 L / min, while keeping the permeate outlet open; when the permeate flow is observed to change from clear wine to continuous bubbles, immediately close the wine inlet valve and switch to injecting gas from the system's residue outlet, and use the continuous exhaust of gas at the highest point of the system as the criterion for the end of the top-liquid treatment; this process is completed within 3-8 minutes.

[0012] Preferably, the gradient compound aging method of the present invention for improving the structure and flavor of mango wine further includes a closed pressure verification step after the criterion for the end of top liquid is met: closing all inlet and outlet valves of the system to make the system completely sealed, monitoring and recording the initial pressure P0; recording the pressure P1 after holding for 30-60 seconds; if the pressure drop ΔP (ΔP = (P0–P1) / P0×100%) does not exceed 5%, it is determined that the top liquid is complete and the system is airtight; if ΔP is greater than 5%, the top liquid treatment is repeated until the verification is passed.

[0013] Preferably, in the gradient compound aging method for improving the structure and flavor of mango wine of the present invention, the closed-loop pressure verification step monitors the real-time temperature T of the system simultaneously with pressure monitoring; the pressure drop ΔP needs to be corrected for temperature compensation according to the gas state equation, and the correction formula is: ΔPcorrected = |(P1 / T1–P0 / T0) / (P0 / T0)| ×100%, where T0 and T1 are the average absolute temperatures (K) of the system measured at the initial and final times, respectively; when ΔPcorrected is greater than 5%, further fault diagnosis is performed based on the decline pattern of P1 and P0: if P1 declines rapidly and then tends to stabilize, it is determined to be a minor leak, and the sealing point needs to be checked; if P1 declines slowly and linearly, it is determined to be an incomplete top-fluiding process leading to an unstable structure in the system, and the top-fluiding process needs to be repeated and the gas injection parameters optimized.

[0014] Preferably, the gradient compound aging method of the present invention for improving the structure and flavor of mango wine introduces pressure change kinetic analysis in the closed-loop pressure verification: within 30-60 seconds after sealing, pressure data is continuously collected at a frequency of not less than 10Hz using a pressure sensor with an accuracy class of not less than 0.5 or an absolute error not exceeding ±0.25% of full scale, and a pressure-time curve is plotted; the curve is analyzed using a piecewise linear regression method to calculate the initial descent slope k1 (first 10 seconds) and the steady-state descent slope k2 (from 10 seconds later to the end); when |k1|>0.05 P0 / s and |k2| / |k1|<0.3, it is determined to be a minor leak; when |k1|≤0.05 When P0 / sec and |k2| is consistently and stably greater than 0, it is determined that the liquid filling is incomplete. Based on the determination result, the optimized gas injection parameters are automatically generated: if it is a minor leak, the system prompts to check the sealing point of a specific high-pressure area; if it is an incomplete liquid filling, the gas flow rate and pressure of the next liquid filling are adaptively adjusted according to the value of k2, with the adjustment range being (10×k2)% of the original parameters, but not exceeding ±30% of the original parameters.

[0015] The slope threshold (e.g., 0.05 P0 / second) is derived from kinetic analysis and extensive experimental verification of an ideal closed gas system after top-fluiding. The underlying principle is that, under ideal conditions of complete top-fluiding and a well-functioning system, the pressure within the closed system should stabilize within a short time, and the initial slope of the pressure-time curve should approach zero. The threshold of 0.05 P0 / second defines a critical state. When the initial descent rate exceeds this relative value (relative to the initial system pressure P0), it indicates the presence of an abnormal rapid pressure release pathway (i.e., leakage). When the initial descent rate is below this threshold but the steady-state slope remains positive, it indicates the existence of a slow pressure release mechanism within the system, typically caused by residual liquid film evaporation or slow equilibrium of an unstable "gas-liquid-gas" structure, indicating incomplete top-fluiding. This relative threshold (the ratio to P0) design ensures the judgment logic is universally applicable and adaptable to systems of different sizes and operating pressures.

[0016] Preferably, in the gradient compound aging method for improving the structure and flavor of mango wine of the present invention, during the top liquid treatment process, the components of the discharged gas are simultaneously monitored as an auxiliary criterion for top liquid treatment: with the permeate outlet open, the discharged gas is monitored in real time to detect the concentration of ethanol; before the top liquid operation begins, the concentration of ethanol in the ambient air is measured at the gas monitoring point at the permeate outlet as the background concentration C0; when the permeate flow is observed to change into continuous bubbles, the concentration of the volatiles is monitored until it decreases and stabilizes below 1.1 times the background concentration C0, and this is used as one of the final criteria for top liquid treatment; if the concentration cannot be reduced below the threshold or exhibits a specific abnormal decay pattern, it indicates that there is a residual liquid film or circulation dead zone in the system; at this time, the gas injection path or parameters are adjusted in a targeted manner based on the real-time decay curve characteristics of the volatile concentration.

[0017] Preferably, in the gradient compound aging method for improving the structure and flavor of mango wine of the present invention, the specific method for optimizing the gas injection path or parameters is as follows: targeted adjustments are made based on the decay curve characteristics of volatile concentration: if the volatile concentration decreases in a stepwise manner and there is a significant plateau period, it is determined that there is a dead end in the circulation path, and an intermediate injection point needs to be added during the next top liquid injection, so that the gas is injected in stages from at least three different positions; if the volatile concentration decreases slowly but steadily without a plateau period, it is determined that the gas displacement power is insufficient, and the gas flow rate needs to be increased linearly according to the ratio of (1+0.2×t / T), where t is the current top liquid injection time and T is the preset standard top liquid injection time, but the total flow rate does not exceed 150% of the original parameters; if the volatile concentration shows periodic fluctuations, it is determined that there is a gas lock effect in the system, and the single continuous injection needs to be changed to pulse injection during the next top liquid injection, with a pulse frequency of 0.5-2 Hz and a duty cycle of 30-70%.

[0018] It should be noted that the inclusion of temperature compensation correction and pressure change kinetic analysis in the above-mentioned preferred scheme involving inert gas top liquid verification has clear technical motivations and considerations: The core purpose of performing a pressure hold test after top-fluid treatment is to quickly and objectively assess the system's sealing performance and the completeness of top-fluid application. However, in actual production environments, even a perfectly sealed system can experience significant changes in its internal pressure readings due to minor fluctuations in ambient temperature (such as equipment heat dissipation or ambient airflow). Judging solely based on the observed initial pressure drop (ΔP) can easily lead to misjudgment, mistaking a qualified system for a leak or incomplete top-fluid application.

[0019] To address the aforementioned technical problems, this invention first introduces temperature compensation correction. The underlying principle is that, according to the ideal gas law (PV=nRT), under the premise that the volume (V) of the sealed container and the amount of gas (n) remain constant, the system pressure (P) is directly proportional to the absolute temperature (T). Therefore, by simultaneously monitoring the pressure (P0, P1) and the corresponding average absolute temperature of the system (T0, T1), and using the correction formula ΔPcorrected = |(P1 / T1 - P0 / T0) / (P0 / T0)| × 100%, the pressure reading error caused by temperature fluctuations can be eliminated. This yields a "true" pressure drop that only reflects the mass loss caused by actual gas leakage or residual liquid evaporation, fundamentally improving the reliability of the verification results.

[0020] Furthermore, to accurately distinguish whether the true cause of the pressure drop is "minor system leakage" or "evaporation of residual liquid film due to incomplete topdressing," this invention introduces pressure change kinetic analysis. The technical motivation lies in the fundamental difference between these two failure modes in the dynamic characteristics of pressure decrease over time: "minor leakage" typically manifests as a rapid pressure drop in the initial stage, followed by a slower, stable leakage rate due to possible partial blockage of the leakage channel or a reduction in the internal and external pressure difference; "incomplete topdressing," on the other hand, typically manifests as a continuous, slow, and almost linear pressure decrease due to the slow evaporation of the residual liquid film. By acquiring high-frequency pressure-time data and calculating the initial slope (k1) and steady-state slope (k2), and setting a judgment threshold based on extensive experimental data (e.g., |k1|>0.05 P0 / second as a criterion for rapid leakage), the failure type can be automatically and accurately distinguished. This provides clear guidance for subsequent maintenance operations (leak detection or repeated topdressing) and lays a data foundation for further adaptive optimization of topdressing parameters.

[0021] In summary, the introduction of temperature compensation correction and pressure change kinetic analysis together constitutes a progressive precision diagnostic system from "eliminating environmental interference" to "identifying fault mechanisms". This system aims to solve the technical problems of high misjudgment rate and unclear fault root cause when relying solely on the endpoint pressure difference for judgment in existing technologies, thereby significantly improving the intelligence level and process reliability of the top liquid verification step.

[0022] Preferably, after completing the cross-flow membrane filtration step and before bottling, the process further includes: drying the mango peel at low temperature, mixing it with edible alcohol or finished mango wine with an alcohol content of 40-60% vol at a weight ratio of 1:5-10, extracting it at 10-15℃ in the dark for 3-7 days, then filtering it to obtain a mango peel flavor concentrate; adding the mango peel flavor concentrate to the clear wine liquid after cross-flow filtration at a ratio of 0.1%-1.0% of the final finished wine volume, stirring and mixing it evenly at low temperature, allowing it to stand, and then performing final fine filtration and bottling.

[0023] The present invention has at least the following beneficial effects: 1. This invention addresses the problems of high acidity, poor flavor, and loose structure in existing mango wines by regulating acidity and removing undesirable flavors through fermentation with domesticated microbial strains, synergistic pretreatment of oak and mango wood, and gradient aging. It achieves efficient degradation of malic acid, precise control of diacetyl, and synergistic release of oak and mango wood flavors, preserving the inherent aroma of mango while enhancing the stability of the wine's structure and the complexity of its flavor profile, thus significantly improving the quality of the mango wine.

[0024] 2. This invention solves the problem of relying on experience and lacking precision in oxygen supply during the later stages of aging by simultaneously implementing controlled micro-oxygen treatment based on a mass balance model during the third stage of mango wood maceration. Through small-scale modeling (M value), the total oxygen demand Q is calculated, and a pulsed oxygen supply plan is formulated, achieving quantitative and phased oxygen supply. Combined with dissolved oxygen concentration detection and feedback adjustments in the mid- and late-stages (increasing ventilation or correcting the model), a closed-loop control of "prediction-execution-monitoring-correction" is formed. This achieves a scientific management effect on the micro-oxidation process of aging: it ensures sufficient oxygen to promote the slow oxidation and polymerization of mango wood components and the wine, resulting in a smoother taste and more integrated flavors, while effectively avoiding the risk of wine quality deterioration due to excessive oxidation, thus improving the stability and reproducibility of the aging process.

[0025] 3. This invention solves the allergen problem of traditional animal-derived clarifying agents by employing a non-animal-derived composite stabilization process using sodium-based bentonite and chitosan derivatives (carboxymethyl chitosan or quaternized chitosan), and expands the product's applicable population. Bentonite primarily removes unstable substances such as proteins, while chitosan derivatives further polymerize residual suspended particles and some polyphenols. The synergistic effect of both results in high clarification efficiency. Subsequent low-temperature, low-pressure cross-flow filtration using a polyvinylidene fluoride membrane provides excellent physical retention. The entire solution achieves efficient and safe removal of unstable factors in the wine (proteins, turbid particles, etc.) while minimizing the adsorption loss of flavor compounds and the wine itself, ensuring the final product's non-animal-derived properties, clarity, biological stability, and flavor integrity.

[0026] 4. This invention solves the problem of poor adaptability of fixed-parameter filtration by dividing the cross-flow filtration process into three stages: a high-flow-rate, low-pressure initiation stage, a stable operation stage, and a low-flow-rate, low-temperature termination stage, and employing different operating parameters. The initial high membrane surface flow rate (3.5-4.0 m / s) and low pressure effectively flush the membrane surface, reducing initial contamination; the intermediate stage adjusts to optimized parameters to ensure stable flux; and the final stage reduces flow rate and temperature (6-10℃) and initiates top liquid preparation, reducing the thermodynamic degradation of the wine at high concentration ratios and the risk of membrane clogging. This achieves the effects of optimizing the filtration process, improving filtration efficiency, and extending membrane lifespan. Simultaneously, the low-temperature top liquid preparation ensures the smooth implementation of subsequent residual wine recovery steps and reduces wine loss due to improper handling.

[0027] 5. This invention solves the problem of ambiguous endpoints in top-flushing operations by specifying a concrete operational procedure for inert gas top-flushing. The main wine is injected from the inlet end to displace it; after observing bubbles, injection is switched to the residue outlet end to clean the high points of the pipeline. Continuous gas emission from the highest point is used as the termination criterion, making the top-flushing process clearly operable. This scheme achieves efficient recovery of residual wine in the dead volume of the system, significantly reducing wine loss, while avoiding the waste of inert gas caused by excessive aeration and the potential additional escape of volatile aroma compounds.

[0028] 6. This invention solves the problem of the inability to quickly and quantitatively assess the thoroughness of top-flushing and the system's airtightness by adding a simple pressure-holding verification step after top-flushing. By monitoring whether the pressure drop ΔP exceeds the threshold (5%) within a short period, the system status can be objectively judged. If ΔP is within acceptable limits, both thorough top-flushing and good system airtightness are verified simultaneously; if ΔP is too large, repeated top-flushing is triggered to ensure the problem is corrected. This achieves rapid and objective quality inspection of the top-flushing effect, forming an operational closed loop, ensuring efficient and reliable residual wine recovery, and laying a safe foundation for subsequent anaerobic preservation or treatment of the wine.

[0029] 7. This invention solves the problem of misjudgment of pressure readings caused by ambient temperature fluctuations by introducing temperature monitoring and temperature compensation correction for pressure drop during pressure holding verification, making the verification results more accurate and reliable. Furthermore, by analyzing pressure drop patterns, it distinguishes between two root causes of failure: "minor leakage" and "incomplete liquid top-up," providing a clear direction for resolution. This improves the diagnostic accuracy of the verification process, guiding operators to take correct maintenance or re-top-up measures, avoiding ineffective operations due to misjudgment, and improving maintenance efficiency.

[0030] 8. This invention solves the problem that static pressure differences cannot reflect the dynamic characteristics of faults by introducing high-frequency pressure data acquisition and dynamic analysis of pressure-time curves (calculating the initial slope k1 and steady-state slope k2). Using preset slope logic criteria, it can more scientifically and automatically distinguish between leakage and incomplete top-fluid application. More importantly, it can automatically generate optimized parameters based on diagnostic results (such as prompting for leak detection or adaptively adjusting top-fluid parameters), achieving advanced effects of intelligent self-diagnosis and parameter self-optimization. This significantly reduces the workload of manual analysis and decision-making, and allows each top-fluid application and verification process to learn and improve based on previous results, continuously optimizing operational efficiency.

[0031] 9. This invention solves the problem that physical observation alone may not be able to detect residual liquid films or vapor dead zones by simultaneously monitoring the concentration of ethanol or mango characteristic aroma in the exhaust gas during top-drinking and using its decay to a baseline as an auxiliary criterion. Gas component monitoring effectively complements "bubble observation" and "pressure verification," offering higher sensitivity. This achieves the effect of multi-dimensional and highly sensitive verification of top-drinking thoroughness, reliably ensuring that all components related to the wine in the system are effectively displaced, further reducing the risk of subsequent batches of wine being affected by possible oxidation or contamination from residues.

[0032] 10. This invention solves the problem of how to adjust operations when top-fluid is incomplete by establishing a mapping relationship between the characteristics of the volatile concentration decay curve and the residual state inside the system, and providing specific optimized injection strategies accordingly. For "step-down" conditions, the injection point is adjusted to eliminate dead zones; for "slow descent" conditions, the flow rate is linearly increased to enhance power; and for "periodic fluctuations," pulse injection is used to break airlocks. This achieves the effect of enabling the top-fluid process to have self-learning and adaptive optimization capabilities, intelligently adjusting operating parameters based on real-time feedback, thereby completing residual alcohol recovery with higher efficiency and thoroughness, and achieving continuous process improvement.

[0033] 11. This invention provides a highly efficient, non-animal-derived composite stabilization and filtration solution that combines the advantages of bentonite and chitosan derivatives to maximize flavor retention while ensuring clarification. More importantly, addressing the challenge of residual liquor recovery at the end of cross-flow filtration, a smart recovery system is constructed integrating "staged variable parameter filtration," "dual-end inert gas top-liquidation," "multi-dimensional verification (bubble observation, pressure / temperature monitoring, gas component analysis)," and "data-driven adaptive optimization." This system not only significantly improves the residual liquor recovery rate (≥95%) and reduces liquor loss and oxidation risks, but also enables self-diagnosis of faults and self-optimization of operating parameters through pressure kinetics and volatile concentration curves, greatly enhancing the automation, reliability, and intelligence of the post-processing steps.

[0034] 12. This invention provides a safe, precise, and reversible flavor enhancement strategy by adding a final mango peel flavor integration step after all core aging and post-processing steps are completed. A concentrated mango peel flavor extract is prepared using a specific low-temperature drying and extraction process and added in precise proportions before bottling. This significantly enhances the vividness and persistence of the mango's unique varietal aromas (such as tropical fruit aromas) in the final product. The added aromas blend naturally with the complex aging process, without any artificiality or separation. This achieves the effect of targeted enhancement of the authentic mango aroma while fully preserving the original complex structure and harmonious flavor of the wine, satisfying the market's preference for products with rich fruit aromas and expanding the product's flavor adjustability. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0036] The *Oenococcus oeni* and *Schizosaccharomyces pombe* used in the first stage of this invention can be commercially available strains. To adapt them to the specific mango wine environment of this invention, it is recommended to perform an adaptation culture before inoculation. The method is as follows: The activated strains are sequentially transferred to adaptation media containing 30%, 60%, and 100% (v / v) of the mango wine to be fermented, and cultured at 20°C for 24-48 hours each, until the cell growth is stable. Through this process, the strains can fully adapt to the alcohol content, pH, and organic acid environment of the mango wine, thereby ensuring their activity and metabolic efficiency in the subsequent main fermentation.

[0037] Example 1 A gradient aging method for enhancing the structure and flavor of mango wine includes the following steps: Step 1: Select the base wine made from "Tainong No. 1" mangoes. After the primary fermentation is completed, adjust the alcohol content to 10.0% vol. The malic acid content is measured to be 4.5 g / L and the pH value is 3.5.

[0038] Step 2: Prepare lightly roasted American white oak chips and "Tainong No. 1" mango wood. Mix the oak chips and mango wood blocks in a weight ratio of 1:2, totaling 30kg.

[0039] Prepare the composite pretreatment solution: 300L of aqueous solution of 2% sodium bicarbonate + 1% sodium citrate (solid-liquid ratio 1:10).

[0040] The mixed wood was immersed in the pretreatment solution and heated in a water bath at 70°C for 3 hours. After draining the wood, it was placed in a steam device and steamed for 30 minutes at a saturated steam pressure of 0.13 MPa.

[0041] The steamed wood is then transferred to a baking oven and baked at 90°C for 1.5 hours, and then the temperature is increased to 130°C for another hour.

[0042] After pretreatment, oak chips and mango wood were separated. Sampling and testing showed that the composition of the oak chips was effectively optimized after the above synergistic pretreatment.

[0043] Step 3, First Stage Aging: Transfer 5000L of the above base wine to a stainless steel fermentation tank. Inoculate with *Oenococcus oeni*, a strain domesticated from mango wine, at an inoculation rate of 3 × 10⁻⁶. 6 CFU / mL; simultaneously inoculated with *Schizosaccharomyces pombe* at a density of 2 × 10⁻⁶. 5 CFU / mL. Fermentation was carried out at 20℃ under sealed conditions. Malic acid and diacetyl levels were monitored daily. On day 15, the malic acid content in the wine decreased to 0.3 g / L, and the diacetyl content decreased to 1.5 mg / L, indicating the end of the first stage. The resulting fruit wine had a smoother taste and developed some secondary aromas similar to cream and nuts.

[0044] Step Four, Second Stage Aging: Add pretreated white oak chips to the first fruit wine at a rate of 5 g / L (total 25 kg). Macerate at 14°C for 45 days. Taste regularly during this period. After maceration, separate the oak chips to obtain the second fruit wine. At this stage, the wine has slightly deepened in color, become noticeably fuller in flavor, and exhibits enhanced tannin structure, incorporating oak flavors such as vanilla and toast, which are initially integrated with the fruit aromas without creating a strong conflict.

[0045] Step 5, Third stage aging: Weigh out the "Tainong No. 1" mango wood blocks that have undergone the above-mentioned synergistic pretreatment and add them to the second fruit wine at an addition rate of 6g / L (a total of 30kg of mango wood blocks are added, with the addition rate ranging from 1 to 10 g / L).

[0046] Continue maceration at 14°C for 60 days.

[0047] Step 6: After the soaking is complete, separate and remove the mango wood blocks to obtain the final mango wine processed by the gradient compound aging method of this invention.

[0048] After tasting, the final mango wine presented a bright golden color and a clear body. Its aroma profile was characterized by a dominant and clearly discernible rich and pure tropical fruit aroma of mango and passion fruit; simultaneously, elegant notes of vanilla and toasted bread, along with a hint of sweet woody fragrance highly harmonious with the fruit aromas, were incorporated into the background. The various aromas were distinct yet well-integrated. On the palate, the wine was full-bodied and rounded, with fine and soft tannins, moderate acidity, and a significantly better structure than the control wine that had not undergone this process. The finish was characterized by a persistent and harmonious blend of fruity and woody notes.

[0049] Example 2 The gradient complex aging method for enhancing the structure and flavor of mango wine differs from Example 1 in that: Step 5, Third Stage Aging (including controlled micro-oxygen treatment): Add the pre-treated mango wood to the second fruit wine at a rate of 6 g / L and continue maceration for 60 days; simultaneously, conduct controlled micro-oxygen treatment based on a mass balance model: a) Model establishment: The cumulative oxygen consumption M per unit mass of mango wood during the 60-day soaking period was determined to be 0.8 mg / g in a small-scale test.

[0050] b) Calculate the total oxygen demand: The total amount of mango wood added is 30 kg, the total volume of the wine is V = 5000 L, and the total oxygen demand is Q = 0.8 mg / g × 30 × 10 3 g = 24000 mg.

[0051] c) Pulsed oxygen supply plan: 60 days of soaking, n=60÷8=7.5, take the integer n=7, divide Q into 7 equal parts, each part is about 3428.6mg; each oxygen supply uses sterile filtered compressed air, which is ventilated through the aeration stone at the bottom of the container. The ventilation rate is 0.2 times the volume of gas per minute per unit volume of wine, and the duration of each ventilation is 2 minutes.

[0052] d) Simple verification and adjustment: At the beginning of the third stage, the dissolved oxygen concentration was measured as 0.3 mg / L, at the middle stage as 0.25 mg / L, and at the end as 0.6 mg / L. The actual cumulative oxygen supply during this aging cycle was recorded and used to calibrate and optimize the value of the cumulative oxygen consumption M per unit mass of mango wood.

[0053] Example 3 The gradient complex aging method for enhancing the structure and flavor of mango wine differs from Example 2 in that: Step 6: (1) Adjust the temperature of the wine after the third stage of maceration to 14°C, add 350 mg / L of sodium bentonite (pre-hydrated and activated at 38°C for 24 hours in 10 times its weight of deionized water); after adding, stir at 25 rpm for 30 minutes, and then let stand at 14°C for 6 days to obtain the first supernatant wine.

[0054] (2) Take the first supernatant and adjust the temperature to 16℃. Add carboxymethyl chitosan clarifying agent at an addition rate of 180 mg / L. Stir at 50 rpm for 15 minutes, then switch to low speed of 15 rpm for 2 hours. Then let it stand at 16℃ for 4 days to obtain the second supernatant.

[0055] (3) The second supernatant was filtered at 10°C using a polyvinylidene fluoride membrane with a pore size of 0.3 μm. The system operating pressure was controlled at 1.5 bar and the membrane surface flow rate was maintained at 3.0 m / s to obtain the finished mango wine.

[0056] Tests showed that the finished wine had a turbidity of 3.5 NTU, posed no animal-derived safety risks, exhibited excellent clarification stability, and retained its flavor components intact.

[0057] Example 4 The gradient complex aging method for enhancing the structure and flavor of mango wine differs from Example 3 in that: The steps for adding staged variable parameter crossflow filtering are as follows: 1. Base wine preparation, wood co-treatment, three-stage aging (including controlled micro-oxygen), and non-animal-derived compound stabilization: the steps are the same as in Example 3, to obtain the second supernatant.

[0058] 2. Staged variable-parameter cross-flow filtration: The second supernatant is cross-flow filtered at 10℃ using a polyvinylidene fluoride membrane with a pore size of 0.3 μm. Specific procedures are as follows: (1) Within the first 15 minutes of filtration, the membrane surface flow rate is maintained at 3.8 m / s and the operating pressure is controlled at 1.2 bar.

[0059] (2) When the turbidity of the permeate drops below 4.2 NTU, adjust the membrane flow rate to 3.0 m / s and slowly increase the operating pressure to 1.8 bar and keep it stable.

[0060] (3) When the remaining wine is 10% of the total volume, the flow rate on the membrane surface is reduced to 2.2 m / s, and the wine temperature is further reduced to 8℃. Immediately, a small amount of inert gas at the same temperature is used to top the circulation pipeline to completely recover the residual wine in the system and obtain the finished mango wine.

[0061] Tests showed that the membrane fouling level was reduced by 30% compared to Example 3, the membrane life was extended, the permeate quality was stable, and the initial efficiency of residual wine recovery reached 92%.

[0062] Example 5 The gradient complex aging method used to enhance the structure and flavor of mango wine differs from Example 4 in that: The parameters for adding inert gas top liquid treatment are as follows: 1. Base wine preparation, wood co-treatment, three-stage aging (including controlled micro-oxygen), non-animal-derived compound stabilization, and staged cross-flow filtration: the steps are the same as in Example 4.

[0063] 2. Inert gas top-liquid treatment: When the remaining wine volume is 10% of the total volume, reduce the membrane flow rate to 2.2 m / s and the wine temperature to 8°C for top-liquid treatment: Use food-grade nitrogen at 8°C to continuously inject from the wine inlet of the filtration system at a constant pressure of 1.0 bar and a flow rate of 100 L / min, while keeping the permeate outlet open; when the permeate flow is observed to change from clear wine to continuous bubbles, immediately close the wine inlet valve and switch to injecting gas from the system's exhaust outlet, and use the continuous exhaust from the highest point of the system as the criterion for the end of top-liquid treatment; this process takes 5 minutes.

[0064] The recovered residual wine is combined with the main filtered wine to obtain the finished mango wine. Calculations show that the residual wine recovery rate within the system's dead volume reaches 96.5%, significantly improving raw material utilization.

[0065] Example 6 The gradient complex aging method for enhancing the structure and flavor of mango wine differs from Example 5 in that: The core technical features of the newly added closed-loop pressure holding verification are as follows: 1. Basic process steps: base wine preparation, wood co-treatment, three-stage gradient aging (i.e., the aging steps with controllable micro-oxygen treatment described in Example 2), non-animal-derived compound stabilization treatment, staged variable parameter cross-flow filtration and inert gas top liquid treatment. The parameters and operations of each step are exactly the same as in Example 5. After the top liquid treatment is completed, the filtered wine and the residual wine are initially combined.

[0066] 2. Sealing and Pressure Holding Verification: Close all inlet and outlet valves of the filtration system to bring the system to a completely sealed state; monitor and record the initial pressure P0 = 1.0 bar in real time using the system pressure sensor; after maintaining the sealed state for 45 seconds, record the system pressure P1 = 0.98 bar again; calculate the pressure drop ΔP according to the formula: ΔP = (P0 – P1) / P0 × 100% = (1.0 – 0.98) / 1.0 × 100% = 2%.

[0067] 3. Result judgment: Since ΔP=2% ≤5%, it is determined that the top liquid treatment is complete and the system airtightness is good, and there is no need to repeat the top liquid treatment; after the initially combined wine is allowed to stand in a conventional manner, the finished mango wine is obtained.

[0068] 4. Effect Verification: The finished mango wine was tested and found to have a malic acid content of 0.38 g / L, a diacetyl content of 1.7 mg / L, a residual wine recovery rate of 96.5%, and a wine turbidity of 3.5 NTU. Compared with Example 5, this example eliminated the risk of top liquid residue and system leakage through closed pressure verification. The finished wine did not show problems such as oxidation, deterioration, turbidity and precipitation during storage, and its stability was significantly improved.

[0069] Example 7 The gradient complex aging method used to enhance the structure and flavor of mango wine differs from Example 6 in that: The newly added core technical features of temperature compensation correction and fault diagnosis, and the specific steps are as follows: 1. Basic process steps: from base liquor preparation to inert gas top liquid treatment, the parameters and operations of each step are exactly the same as in Example 5, and the top liquid treatment is completed.

[0070] 2. Sealing and pressure holding verification (including temperature compensation and fault diagnosis): (1) Closed monitoring: Close all inlet and outlet valves of the system, and simultaneously turn on the pressure sensor and temperature sensor to monitor and record the initial pressure P0=1.0 bar and the initial average system temperature T0=8℃ in real time; after maintaining the closed state for 45 seconds, record the pressure P1=0.97 bar and the end temperature T1=8.2℃.

[0071] (2) Temperature compensation correction: Convert the temperature to absolute temperature (K), T0 = 8 + 273.15 = 281.15 K, T1 = 8.2 + 273.15 = 281.35 K; Calculate the pressure drop after compensation according to the correction formula derived from the gas law: ΔPcorrected = |(P1 / T1Substituting the data, we get ΔPcorrected = |(0.97 / 281.35–1.0 / 281.15) / (1.0 / 281.15)| × 100% ≈ 2.98% ≤ 5%.

[0072] (3) Fault diagnosis simulation: In order to verify the diagnostic logic, a minor leakage scenario was set up and pressure holding verification was performed again: the initial pressure P0=1.0 bar, T0=8℃, the pressure dropped rapidly to 0.92 bar within 10 seconds, and then tended to stabilize (P1=0.91 bar at 45 seconds); according to the drop pattern, P1 showed "rapid drop and then tended to stabilize", which was determined to be a minor leakage in the system. The high pressure area gasket was stopped and checked. After replacement, it was re-verified. ΔPcorrected=1.8%, which was qualified.

[0073] 3. Finished product processing: Combine the qualified wines and let them stand to obtain the finished mango wine.

[0074] 4. Effect verification: After testing, the various indicators of the finished wine are comparable to those of Example 6. After temperature compensation correction, the pressure drop calculation error was reduced from ±0.5% to ±0.1%, effectively avoiding misjudgment caused by temperature fluctuations. The fault diagnosis function can accurately distinguish between leakage and incomplete liquid top-drinking, reducing blind rework and improving production efficiency.

[0075] Example 8 The gradient complex aging method for enhancing the structure and flavor of mango wine differs from Example 7 in that: The core technical features of the newly added pressure change dynamics analysis and adaptive parameter optimization are as follows: 1. Basic process steps: from base liquor preparation to inert gas top liquid treatment, the parameters and operations of each step are exactly the same as in Example 5, and the first top liquid treatment is completed.

[0076] 2. Validation of pressure holding in a closed loop (including kinetic analysis and adaptive optimization): (1) Dynamic data acquisition: After closing the system valve, pressure data was continuously acquired at a frequency of 1Hz for 45 seconds, and pressure-time curve was plotted; the first 10 seconds were selected as the initial stage, and 10-45 seconds were selected as the steady state stage.

[0077] (2) Slope calculation and fault judgment: Through piecewise linear regression analysis of the curve, the initial descent slope k1 = -0.015 P0 / second (absolute value |k1| = 0.015 ≤ 0.05 P0 / second) and the steady-state descent slope k2 = -0.003 P0 / second (continuously stable greater than 0) were calculated. According to the judgment rules, it was judged as "incomplete top liquid".

[0078] (3) Adaptive parameter optimization: Calculate the adjustment range based on the k2 value: Adjustment range = 10 × |k2| × 100% = 10 × 0.003 × 100% = 3%, within the limit of ±30%; adjust the gas flow rate of the next top liquid from 100 L / min to 103 L / min and the pressure from 1.0 bar to 1.03 bar (in actual production, it can be simplified to an adjustment of about 3%).

[0079] (4) Optimization verification: The top liquid treatment was carried out again according to the adjusted parameters, and the pressure data was collected again. The calculated values ​​were k1 = -0.008 P0 / second and k2 = -0.0005 P0 / second (approaching 0). It was determined that the top liquid was complete and the system was airtight.

[0080] 3. Finished product processing: Combine the qualified wines and let them stand to obtain the finished mango wine.

[0081] 4. Effect Verification: The test results showed that the residual wine recovery rate of the finished wine increased to 96.8%, and the fault diagnosis accuracy increased from 85% to 98% compared with Example 7. The adaptive parameter optimization does not require manual intervention and can be dynamically adjusted according to the actual working conditions. It is especially suitable for scenarios such as equipment aging and working condition fluctuations in large-scale production, reducing the difficulty of operation.

[0082] Example 9 The gradient complex aging method for enhancing the structure and flavor of mango wine differs from Example 8 in that: The process proceeds to the top liquid treatment stage, during which a volatile matter concentration monitoring step is added. The specific steps are as follows: 1. Basic process steps: base wine preparation, wood co-treatment, three-stage aging (including controlled micro-oxygen), non-animal-derived compound stabilization treatment, staged variable parameter cross-flow filtration. The parameters and operations of each step are exactly the same as in Example 5, and then the top liquid treatment stage begins.

[0083] 2. Inert gas top-liquid treatment (including volatile matter concentration monitoring): (1) Top liquid operation: Turn on the 8℃ food-grade nitrogen injection, with a pressure of 1.0 bar and a flow rate of 100 L / min at the inlet end, and keep the permeate outlet open.

[0084] (2) Auxiliary criterion monitoring: An online gas component monitor is set at the outlet of the permeate to detect the concentration of ethanol in the exhaust gas in real time; the ethanol concentration is 850 ppm in the initial stage and gradually decreases as the top liquid is produced.

[0085] (3) Dual criteria determination: When the permeate flow changes from clear liquid to continuous bubbles (primary criterion), the ethanol concentration is monitored. After 3 minutes, the ethanol concentration decreases and stabilizes below 1.08 times the baseline level (baseline concentration 80 ppm) (86.4 ppm), triggering the top liquid end signal and closing the gas injection valve.

[0086] (4) Abnormal scenario verification: The system dead zone scenario was set manually. After continuous bubbles were observed during the top liquid, the ethanol concentration remained at 200 ppm (1.25 times the baseline) and fluctuated. It was determined that there was residual liquid film / dead zone in the system. The top liquid was suspended, the bends in the pipeline were checked, and after cleaning, the top liquid was restarted. Finally, the ethanol concentration stabilized below 85 ppm (1.06 times the baseline), which was qualified.

[0087] 3. Subsequent verification: The pressure-holding verification (including kinetic analysis) was carried out according to the steps in Example 8, and the results were satisfactory.

[0088] 4. Finished product processing: Combine the qualified wines and let them stand to obtain the finished mango wine.

[0089] 5. Effect Verification: The test results showed that the recovery rate of residual liquor in the finished product increased to 97%, and the residual ethanol content decreased to below 0.02 g / L. The dual criteria effectively made up for the limitations of the single bubble criterion, avoiding the waste of residual liquor and flavor loss caused by dead zones in the system, and significantly improving the stability of the top liquid effect.

[0090] Example 10 The gradient complex aging method for enhancing the structure and flavor of mango wine differs from Example 9 in that: The process then proceeds to the top liquid treatment stage, where an injection parameter optimization step based on the volatile decay curve is added. The specific steps are as follows: 1. Basic process steps: from base liquor preparation to the pre-treatment of top liquid, the parameters and operations of each step are exactly the same as in Example 9, and then proceed to the top liquid treatment stage.

[0091] 2. Inert gas top-liquid treatment (including volatile matter attenuation analysis and parameter optimization): (1) Acquisition of decay curve: Turn on the monitoring of top liquid and volatiles, record the change of ethanol concentration over time in real time, and plot the decay curve of volatile concentration.

[0092] (2) Curve feature analysis and problem identification: Scenario 1: The decay curve shows a “step-like decline + obvious plateau period” (the concentration drops from 850 ppm to 300 ppm in 0-2 minutes, remains at 280-300 ppm in 2-4 minutes, and continues to decline after 4 minutes), which is judged as a “dead end of the circulation path” according to the rules.

[0093] Scenario 2: The decay curve shows a "slow and steady decline with no plateau" (the concentration slowly decreases from 850 ppm to 120 ppm in 0-6 minutes), which is judged as "insufficient gas displacement power".

[0094] Scenario 3: The decay curve shows "periodic fluctuations" (the concentration fluctuates repeatedly between 150-250 ppm), which is determined to be "airlock effect".

[0095] (3) Targeted parameter optimization: For scenario 1 (circulation dead zone): Add an injection point in the middle of the pipeline during the next top liquid injection. Gas is injected in stages from three positions: the inlet, the middle point, and the outlet (2 minutes per position). After optimization, the curve has no plateau period, and the ethanol concentration stabilizes at 82 ppm after 6 minutes.

[0096] For scenario 2 (insufficient displacement): linearly increase the gas flow rate according to the formula (1+0.2×t / T) (t is the current top liquid time, T=5 minutes preset standard time); when t=0, the flow rate is 100 L / min, and when t=5 minutes, the flow rate is 100×(1+0.2×5 / 5)=120 L / min (not exceeding 150% of the original parameter); after optimization, the concentration drops to 85 ppm within 4 minutes.

[0097] For scenario 3 (airlock effect): the continuous injection was changed to pulsed injection with a pulse frequency of 1 Hz and a duty cycle of 50%; after optimization, the fluctuation was eliminated and the concentration stabilized at 83 ppm after 5 minutes.

[0098] 3. Subsequent verification: The pressure-holding verification (including kinetic analysis) was carried out according to the steps in Example 8, and the results were satisfactory.

[0099] 4. Finished product processing: Combine all qualified wines and let them stand as usual to obtain the finished mango wine.

[0100] 5. Effect Verification: Testing revealed that the finished mango wine contained 0.35 g / L malic acid, 1.5 mg / L diacetyl, a 97.2% residual wine recovery rate, 3.2 NTU turbidity, and a sensory score of 94 points (aroma 30 points, taste 38 points, color 15 points, overall harmony 11 points). Compared to the previous embodiment, the synergistic effect of all technical features resulted in a richer flavor profile, a higher degree of integration between the inherent mango aroma and oak aroma, and optimal levels of raw material utilization, production efficiency, and finished product stability, fully demonstrating the technical advantages of this invention.

[0101] To objectively diagnose the state of the top liquid system, the volatile concentration decay curve is quantitatively analyzed, and the following characteristic parameters and judgment rules are defined: 1. Plateau Detection: If, in continuously monitored concentration-time data, there exists a range of time ≥ Δtp (e.g., 20 seconds), and the difference between the maximum and minimum concentrations within this range is ≤ ΔCp (e.g., 5% of the baseline concentration C0), then this range is considered a "significant plateau." If the entire curve contains one or more significant plateaus, it is considered that there is a dead end in the cyclic path.

[0102] 2. Calculation of average decay rate: Calculate the average decay rate Vavg = (Cstart - Cbubble) / Tavg from the start of the top liquid (concentration Cstart) to the observation of continuous bubbles (concentration Cbubble). If Vavg ≤ Vth (e.g., C0 / min), it is determined that the gas displacement power is insufficient.

[0103] 3. Periodic fluctuation detection: The concentration sequence after observing continuous bubbles is detrended and then subjected to Fast Fourier Transform (FFT) or its autocorrelation function is calculated. If there is a significant power spectral peak in the frequency range fth (e.g., 0.1 Hz ~ 2 Hz), or if its autocorrelation function exhibits periodic oscillations, it is determined that there is an airlock effect in the system.

[0104] Example 11 The gradient aging method for enhancing the structure and flavor of mango wine, based on Examples 1-10, adds a final mango peel flavor integration step before bottling. This aims to precisely enhance the aroma of the mango variety while fully preserving the wine's structure and flavor integration achieved through the original process. The specific steps are as follows: 1. Place the mango peel in saturated steam at 90-100℃ for 30-90 seconds, then quickly cool and drain. Spread the drained fresh mango peel evenly and bake at an initial temperature of 45-50℃ and relative humidity of 30-40% for 1-2 hours; then raise the temperature to 55-60℃ and reduce the relative humidity to 15-25%, and continue baking for 2-4 hours; until the moisture content of the mango peel drops to 8%-12% and the texture becomes supple and leathery, without being burnt or brittle.

[0105] 2. Preparation of mango peel flavor concentrate: Crush the processed mango peels and mix them with 50% vol food-grade alcohol (or a portion of high-alcohol finished mango wine) at a weight ratio of 1:8. Incubate at 12℃ in the dark for 5 days, stirring gently once daily. After extraction, perform solid-liquid separation using a plate and frame filter press, followed by fine filtration through a 0.45 μm membrane to obtain a clear, aromatic mango peel flavor concentrate. Store in a sealed, dark place at 4℃ for later use.

[0106] 3. Take the final mango wine prepared in Examples 1-10 and add it precisely to a blending tank at 8-10℃ while slowly stirring at 15 rpm. The amount added needs to be determined through small-scale testing, and is usually 0.2% to 0.8% of the total volume of the finished wine (0.5% is used in this example). Continue stirring at low speed for 2 hours, and let it stand at 2-4℃ for 48 hours to observe flavor integration and sedimentation. After standing, the wine is sterilized under aseptic conditions using a 0.22 μm membrane and then immediately bottled to obtain the finished mango wine.

[0107] 4. Evaluation of Results: The mango wine processed using this method was blind-tasted by a professional sensory evaluation team. The consensus was that while perfectly preserving the full-bodied structure and complex flavor profile of the harmonious blend of oak and mango wood inherent in the original process, the vividness and persistence of the mango's distinctive tropical fruit aroma were significantly enhanced. Furthermore, the newly added aromas integrated naturally with the overall flavor of the wine, without any sense of separation or artificial addition. The physicochemical indicators remained stable, and turbidity did not increase.

[0108] This embodiment demonstrates that adding a precise flavoring step based on mango peel flavor concentrate at the terminal is a safe, effective, and highly controllable flavor enhancement strategy. It can further optimize the aroma performance of the product without interfering with the core process, and meet the market's preference for a richer, more authentic mango flavor.

[0109] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Further modifications can be readily implemented by those skilled in the art.

Claims

1. A gradient complex aging method for enhancing the structure and flavor of mango wine, characterized in that, include: The base wine is mango wine with an alcohol content of 9.5-10.5% vol, a malic acid content of 3.0-6.0 g / L, and a pH value of 3.4-3.6 after primary fermentation. Wood materials for aging are prepared, including lightly or moderately roasted American white oak or French oak chips, as well as mango tree wood of the same species as the winemaking materials. First, the wood raw materials undergo synergistic pretreatment: oak chips and mango wood are mixed at a weight ratio of 1:1-3 and placed in a composite aqueous solution of sodium bicarbonate (1-3% by mass) and sodium citrate (0.5-1.5% by mass), with a solid-liquid ratio of 1:5-10. The mixture is then soaked at 60-80℃ for 2-4 hours. After draining until there is no obvious flowing water on the surface, the mixture is steamed at a saturated steam pressure of 0.12-0.15 MPa for 20-40 minutes. Then, a gradient temperature baking process is carried out, baking at 80-100℃ for 1-2 hours, and then increasing to 120-150℃ for 0.5-2 hours. Then, the base spirit is aged in the following three stages: Phase 1: The mango wine that has completed primary fermentation is placed in a stainless steel tank, and *Schizophyllum commune* and *Schizophyllum esculentum* are added for fermentation. Before inoculation, *Schizophyllum commune* and *Schizophyllum esculentum* should be adapted to the mango wine substrate environment of 9.5-10.5% vol and pH 3.4-3.

6. Fermentation is carried out under airtight conditions at 18-22℃. This phase is considered complete when the malic acid content in the wine drops below 0.5 g / L and the diacetyl content drops below 2 mg / L, yielding the first fruit wine. The inoculation amount of *Schizophyllum commune* is 1×10⁻⁶. 6 -5×10 6 CFU / mL, the inoculum size of *Schizosaccharomyces cerevisiae* was 1×10⁻⁶. 4 -5×10 5 CFU / mL; Second stage: Add the pretreated oak chips to the first fruit wine at a rate of 2-8 g / L and macerate at 12-16℃ for 30-60 days to obtain the second fruit wine. Third stage: Add the pre-treated mango wood to the second fruit wine at a rate of 1-10 g / L and continue to soak for 15-90 days.

2. The gradient compound aging method for improving the structure and flavor of mango wine as described in claim 1, characterized in that, Concurrently with the third stage, a controlled micro-oxygen treatment based on a mass balance model is also carried out, specifically including: a) Model establishment: Before the start of the third stage, the cumulative oxygen consumption per unit mass of mango wood during the 15-90 day soaking period was determined by small-scale test as M; b) Calculate the total oxygen demand: Based on the total amount of mango wood added in the third stage and the total volume of the wine V, calculate the total oxygen demand Q = M × total mass of wood; c) Divide the total oxygen demand Q into n equal parts to form an n-pulse oxygen supply plan; during each oxygen supply, use sterile filtered compressed air to ventilate through aeration stones located at the bottom of the container. The ventilation rate is 0.1 to 0.3 times the volume of gas per unit volume of wine per minute, and the duration of each ventilation is 1 to 3 minutes; where n is the integer obtained by dividing the number of maceration days by a selected value in the range of 5 to 10 and then rounding it up. d) Simple verification and adjustment: At the beginning, middle and end of the third stage, the dissolved oxygen concentration of the wine is measured using a portable dissolved oxygen meter; in the middle stage, if the results of three consecutive measurements are all below 0.2 mg / L, the ventilation time is increased by 10%-30% in subsequent pulses; if the dissolved oxygen concentration is above 0.8 mg / L in any measurement or at the end, the subsequent pulse oxygen supply plan is stopped, and the actual cumulative oxygen supply for this aging cycle is recorded; this cumulative oxygen supply will be used to calibrate and optimize the value of the cumulative oxygen consumption M per unit mass of mango wood; the interval between each measurement shall not exceed 5 days.

3. The gradient compound aging method for improving the structure and flavor of mango wine as described in claim 1, characterized in that, After all aging stages are completed, a non-animal-derived compound stabilization and filtration step is also included: After the third stage of maceration, adjust the temperature of the wine to 12-16℃, add 200-500 mg / L of sodium bentonite, which has been pre-hydrated and activated in 10 times its weight of deionized water at 35-40℃ for 24 hours; after adding, stir at 20-30 rpm for 30 minutes, and then let it stand at the same temperature for 5-7 days to obtain the first supernatant wine. Take the first supernatant and adjust its temperature to 14-18℃. Add chitosan derivative clarifying agent at an addition rate of 50-300 mg / L. Stir at 40-60 rpm for 15 minutes, then switch to low speed stirring at 10-20 rpm for 2 hours. Then let it stand at 14-18℃ for 3-5 days to obtain the second supernatant. The second supernatant was filtered in a cross-flow manner using a polyvinylidene fluoride membrane with a pore size of 0.2-0.45μm at 8-12℃. The system operating pressure was controlled at 1.0-2.0 bar, and the membrane surface flow rate was maintained at 2-4 m / s. The chitosan derivative clarifying agent is carboxymethyl chitosan or quaternized chitosan with a number average molecular weight of 50,000-500,000 Daltons and a degree of deacetylation ≥85%.

4. The gradient compound aging method for improving the structure and flavor of mango wine as described in claim 3, characterized in that, The cross-flow membrane filtration process employs a staged, variable-parameter operation, specifically including: During the first 10-20 minutes of filtration, maintain the membrane flow rate at 3.5-4.0 m / s and control the operating pressure at the lower limit of 1.0-1.5 bar. Once the turbidity of the permeate obtained from the membrane module outlet drops below 5 NTU, adjust the membrane surface flow rate to 2.5-3.5 m / s, and slowly increase the operating pressure to 1.5-2.0 bar and keep it stable. When the remaining liquid is 8-12% of the total volume, reduce the membrane flow rate to 2.0-2.5 m / s, and further reduce the liquid temperature to 6-10℃. Immediately use food-grade inert gas at 6-10℃, 0.5-1.5 bar, and 50-150 L / min to top-treat the circulation pipeline and completely recover the residual liquid in the system.

5. The gradient compound aging method for improving the structure and flavor of mango wine as described in claim 4, characterized in that, The inert gas top-liquid treatment specifically involves: Use food-grade nitrogen or argon gas at the same temperature of 6-10℃, and continuously inject it from the wine inlet of the filtration system at a constant pressure of 0.5-1.5 bar and a flow rate of 50-150 L / min, while keeping the permeate outlet open. When the liquid flow changes from clear liquid to continuous bubbles, immediately close the inlet valve and switch to injecting gas from the system's exhaust outlet. Use the continuous exhaust from the highest point of the system as the criterion for the end of the liquid topping process; this process is completed within 3-8 minutes.

6. The gradient compound aging method for improving the structure and flavor of mango wine as described in claim 5, characterized in that, After the criterion for the end of top liquid is met, a further step of closed pressure holding verification is performed: Close all inlet and outlet valves of the system to make the system completely sealed, monitor and record the initial pressure P0; after holding for 30-60 seconds, record the pressure P1; if the pressure drop ΔP (ΔP = (P0–P1) / P0 × 100%) does not exceed 5%, it is determined that the top liquid is complete and the system is airtight; if ΔP is greater than 5%, the top liquid treatment is repeated until the verification is passed.

7. The gradient compound aging method for improving the structure and flavor of mango wine as described in claim 6, characterized in that, During the pressure testing process, the real-time temperature T of the system is monitored simultaneously with the pressure monitoring. The pressure drop ΔP needs to be corrected for temperature compensation according to the gas law. The correction formula is: ΔP_corrected = |(P1 / T1 – P0 / T0) / (P0 / T0)| × 100%, where T0 and T1 are the average absolute temperatures (K) of the system measured at the initial and final times, respectively. When ΔP_corrected is greater than 5%, further fault diagnosis is performed based on the descent patterns of P1 and P0: if P1 decreases rapidly and then stabilizes, it is determined to be a minor leak, and the sealing point needs to be checked; if P1 decreases slowly and linearly, it is determined to be an incomplete top-fluid filling that causes an unstable structure in the system, and the top-fluid filling needs to be repeated and the gas injection parameters optimized.

8. The gradient compound aging method for enhancing the structure and flavor of mango wine as described in claim 7, characterized in that, Introduce pressure change kinetic analysis into the closed-loop pressure holding verification: Within 30-60 seconds after sealing, pressure data is continuously collected at a frequency of not less than 10Hz using a pressure sensor with an accuracy class of not less than 0.5 or an absolute error of not more than ±0.25% of the full scale, and a pressure-time curve is plotted. By analyzing the dynamic characteristics of the pressure-time curve, it is possible to distinguish whether the discrete system state belongs to a minor leak or incomplete top fluid filling. Based on the judgment results, optimized operation instructions are automatically generated: if it is a minor leak, the system prompts to check the sealing point of a specific high-pressure area; if the liquid capping is incomplete, the system automatically generates gas injection parameters to optimize the next liquid capping process.

9. The gradient complex aging method for enhancing the structure and flavor of mango wine as described in any one of claims 5-7, characterized in that, During the top liquid treatment process, the composition of the discharged gas is also monitored simultaneously as an auxiliary criterion for top liquid determination: With the liquid outlet open, the discharged gas is monitored in real time to detect the concentration of ethanol in it; Before the top liquid operation begins, the concentration of ethanol in the ambient air is measured at the gas monitoring point at the outlet of the permeate as the background concentration C0. After the permeate flow is observed to change into continuous bubbles, the concentration of the volatiles is monitored until it decreases and stabilizes below 1.1 times the background concentration C0, and this is used as one of the final criteria for top liquid operation. If the concentration cannot be reduced below the threshold or exhibits a specific abnormal decay pattern, it indicates the presence of a residual liquid film or a dead zone in the system. In this case, the gas injection path or parameters are adjusted accordingly based on the real-time decay curve characteristics of the volatile concentration.

10. The gradient complex aging method for enhancing the structure and flavor of mango wine as described in any one of claims 3-9, characterized in that, After completing the cross-flow membrane filtration step and before filling, the process also includes: After drying the mango peel at low temperature, it is mixed with edible alcohol or finished mango wine with an alcohol content of 40-60% vol at a weight ratio of 1:5-10, and extracted at 10-15℃ in the dark for 3-7 days. After filtration, the mango peel flavor concentrate is obtained. The mango peel flavor concentrate is added to the clear wine that has been cross-flow filtered at a ratio of 0.1%-1.0% of the final finished wine volume. The mixture is stirred at low temperature until homogeneous, and then allowed to stand before final filtration and bottling.