Preparation method of aroma-enhanced fermentation product and application method for maintaining flavor stability of aroma-enhanced fermentation product in baking of chips

Abstract

The invention relates to the technical field of food processing, and particularly discloses a preparation method of a flavor-enhanced fermented product and an application method for maintaining flavor stability of the flavor-enhanced fermented product in baking of chips. The preparation method comprises the following steps: cooperatively fermenting natural raw materials through multiple strains / enzyme preparations, and carrying out post-treatments such as customized culture medium preparation, controllable fermentation and inactivation, concentration and homogenization to prepare a pasty aroma-enhanced fermentation product rich in flavor precursors such as amino acids and reducing sugar; the preparation method comprises the following steps: diluting into an aqueous solution with a specific formula, spraying the aqueous solution on the surfaces of chips subjected to vacuum oil bath pretreatment, performing shallow penetration, and matching with the steps of segmented low-temperature baking, seasoning enhancement, nitrogen-filled packaging and the like to obtain a finished product. By means of four mechanisms of flavor precursor supply, anchoring slow release, physical barrier and synergistic enhancement, the flavor plumpness of the chips is improved, the shelf life and flavor stability are prolonged, meanwhile, low-fat health and clean label attributes are considered, technological parameters are quantified clearly, and the method is suitable for industrial large-scale production and has a wide application prospect. And a high-efficiency technical scheme is provided for stable flavor control of high-end baked French fries.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to the interdisciplinary field of potato snack food processing and food biotechnology, and particularly to a method for preparing a flavor-enhancing ferment, and a method for using the flavor-enhancing ferment to maintain the flavor stability of the product during the baking process of French fries. Background Technology

[0002] French fries, a globally popular potato-based snack, have seen their processing technology continuously evolve as consumers' demands for taste, health, and flavor have increased. Currently, the mainstream French fries processing technologies on the market can be divided into two main directions: one is the frozen French fries commonly seen in catering settings, which require high-temperature frying before consumption. While these products can quickly achieve a crispy texture, they generally suffer from high oil content and insufficient health benefits, and the frying process easily leads to the loss of the raw material's own flavor; the other is ready-to-eat French fries sold in retail channels, which mostly use compound potato puree molding or thin-cut potato chip processes. To enhance the flavor, they usually rely on external seasoning powder. However, the external powder can only adhere to the surface of the product, easily resulting in an uneven flavor phenomenon of "strong on the outside and weak on the inside." Moreover, the molding process can damage the natural fiber structure of potatoes, resulting in a lack of authentic taste and chewiness.

[0003] In recent years, the demand for complex flavors, such as honey butter, has continued to grow in the snack food sector. However, when applying these flavors to whole-cut or natural-form French fries, existing technologies have revealed significant technical bottlenecks: First, traditional seasoning methods (such as directly adding flavor compounds or dusting with powder) cannot provide sufficient and stable flavor precursors for the French fry baking process. The Maillard reaction (the core reaction for flavor formation) relies solely on the limited protein and carbohydrates in potatoes, resulting in a limited variety and insufficient intensity of flavor compounds, leading to a lack of flavor "fullness" in the finished product. Second, the high temperatures during baking... The environment easily accelerates the escape of volatile aroma molecules (such as pyrazines and furans), and the lack of an effective flavor-locking mechanism causes the product's flavor to decay rapidly during its shelf life, resulting in the problem of "rich flavor when first produced, but bland flavor after short-term storage." Furthermore, some technologies add excessive artificial flavorings or flavorings to enhance flavor, which not only fails to meet current consumer demands for "clean labels" but also makes it difficult to achieve synergy between flavor and taste. In addition, existing processing techniques, whether high-temperature frying or high-temperature baking, easily damage the stability of flavor substances and cannot simultaneously meet the dual demands of low-fat health and rich flavor.

[0004] Although technologies for preparing flavor enhancers using microbial fermentation have emerged in the food biotechnology field (such as generating flavor precursors through yeast and lactic acid bacteria fermentation), existing technologies are mostly applied to condiments and meat products. There is a lack of dedicated methods for preparing flavor-enhancing ferments specifically for the unique processing scenarios of French fry baking (such as the risk of flavor loss due to high temperatures and the need to balance surface adhesion and shallow penetration). Furthermore, a complete technological chain encompassing "fermentation preparation, spray coating, low-temperature baking, and flavor stabilization" has not been established. In summary, existing French fry processing technologies struggle to simultaneously address core pain points such as insufficient flavor, fleeting flavor, and the conflict between health attributes and clean labeling. Therefore, there is an urgent need in this field for a novel technological solution that can provide long-lasting flavor stability support for the French fry baking process. Summary of the Invention

[0005] In view of this, the purpose of this invention is to overcome the technical defects of existing French fry processing technology, such as insufficient flavor, fleeting flavor, and difficulty in balancing health attributes and clean label requirements. It provides a method for preparing a flavor-enhancing ferment, and a method for using this flavor-enhancing ferment to maintain flavor stability during French fry baking. Specifically, the method aims to obtain a flavor-enhancing ferment rich in flavor precursors, providing sufficient flavor precursors for the French fry baking process and solving the problems of limited flavor variety and lack of fullness in finished products caused by traditional seasoning methods. Simultaneously, the application of this flavor-enhancing ferment achieves flavor locking and long-lasting sustained release, solving the problems of easy escape of volatile aroma molecules during baking and rapid flavor decay during product shelf life. Furthermore, while improving flavor quality, it also considers the low-fat health attributes and clean label requirements of the product, ultimately constructing a complete technical solution suitable for automated large-scale production, providing food processing enterprises with a solution for stable flavor in high-end baked French fries.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for preparing a flavoring ferment, comprising: (1) Selection of strains: Select microorganisms or enzyme preparations with strong aroma-producing ability, or use a combination of microorganisms and enzyme preparations; (2) Culture medium preparation: Based on carbon source, nitrogen source and phosphate, flavor components are added to prepare a culture medium for cell growth and flavor substance synthesis; (3) Controlled fermentation: Under specific temperature, pH and aerobic conditions, the strains selected in step (1) are inoculated into the culture medium prepared in step (2) for fermentation, and the fermentation endpoint is controlled to accumulate the target flavor precursor substances. (4) Post-processing: The fermentation broth is inactivated, concentrated and homogenized to obtain a slurry-like flavor-enhancing fermentation product.

[0007] Furthermore, the microorganisms in step (1) include at least one of Saccharomyces cerevisiae and Lactobacillus helveticus; the enzyme preparation includes at least one of flavor protease and hydrolase; or a multi-component synergistic combination of the above-mentioned microorganisms and enzyme preparations is used.

[0008] Furthermore, the carbon source in step (2) includes glucose, the nitrogen source includes yeast extract, and the flavor ingredients include at least one of butter, honey, and wheat gluten.

[0009] Furthermore, the specific temperature in step (3) is 50-65°C, the pH is 4.5-5.5, and fermentation is carried out under aerobic conditions.

[0010] Furthermore, the post-processing of step (4) includes: heating and inactivating the fermentation broth, then adjusting the concentration of the fermentation broth by vacuum concentration, and finally homogenizing the fermentation material to make it into a uniform slurry.

[0011] A second aspect of the present invention provides a method for maintaining flavor stability during the baking of French fries, comprising: (1) Pretreatment of French fries: The potato raw materials are processed sequentially to obtain French fries to be baked. The processing includes selection, washing, peeling, cutting into strips, blanching, cooling, quick freezing, and may include a vacuum oil bath step. (2) Spraying of flavoring fermentation product: dilute the flavoring fermentation product prepared by any one of claims 1 to 5 into an aqueous solution, spray it onto the surface of the pretreated French fries and allow it to penetrate shallowly; (3) Low-temperature baking: The coated fries are baked at low temperature to complete the shaping and flavor generation; (4) Subsequent processing: The finished product is obtained by cooling and packaging.

[0012] Furthermore, the formulation of the flavoring fermented product aqueous solution in step (2) is selected from one of the following two (by mass percentage): Formula 1: 5-40% flavoring fermented ingredients, 5-20% salt powder, 40-90% water; Formula 2: 40-90% flavoring fermented ingredients, 10-60% water.

[0013] Furthermore, the amount of the flavor-enhancing fermented product aqueous solution sprayed in step (2) is 1.5 to 5.5% based on the weight of the French fries.

[0014] Furthermore, after step (2) and before step (3), a flavor enhancement step is included: sprinkling flavor seasoning powder on the surface of the fries, wherein the amount added is 3 to 7% by weight of the fries.

[0015] Furthermore, the low-temperature baking conditions described in step (3) are 120–150°C for 15–25 minutes.

[0016] The present invention, by adopting the above technical solution, has at least the following beneficial effects: In this invention, the aroma-enhancing fermentation preparation process, which involves "selection of aroma-producing microorganisms / enzymes, customized culture medium preparation, controllable fermentation, and precise post-processing," can directionally enrich flavor precursors such as amino acids and reducing sugars. The resulting fermentation product is a slurry system, which is convenient for subsequent dilution and spraying. Compared with fermented aroma-enhancing substances that are not customized for the French fry baking scenario, this solution helps to expand the spectrum of flavor precursors, providing a more sufficient "raw material library" for the Maillard reaction to continue during the baking process, thereby improving the fullness and layering of the finished product's flavor from the source.

[0017] In this invention, the flavor-enhancing ferment is diluted and sprayed onto the surface of pre-treated French fries to achieve shallow penetration. Combined with a low-temperature baking process of 120-150℃ for 15-25 minutes, on the one hand, the large molecules such as proteins / polysaccharides in the ferment can form a physical barrier on the surface, reducing the escape of volatile aroma molecules and the loss of internal moisture. On the other hand, the small molecule peptides / aroma molecules in the ferment may achieve flavor anchoring and slow release through non-covalent interactions with the matrix, thereby slowing down the flavor decay of traditionally baked French fries during processing and storage, and improving flavor stability during shelf life.

[0018] In this invention, the flavor-enhancing fermented product uses natural raw materials such as butter, honey, and wheat gluten as substrates, and achieves flavor enhancement through microbial fermentation rather than simply relying on artificial flavorings. The pretreatment stage of the French fries can be combined with a vacuum oil bath to replace or reduce the adverse effects of traditional high-temperature frying. While enhancing the flavor, it also takes into account the requirements of clean labeling and low-fat health attributes, alleviating the contradiction of "flavor enhancement and health / labeling are difficult to balance" in the existing technology, and adapting to the product positioning of high-end potato snack foods.

[0019] In this invention, key parameters for the preparation of flavor-enhancing fermented products and their application in French fries (such as fermentation temperature of 50-65℃, pH of 4.5-5.5, spraying amount of 1.5-5.5%, and baking temperature of 120-150℃) are quantitatively set, and the process flow of "pretreatment, spraying, baking, and packaging" is smoothly connected, making it easy to integrate with automated production lines to achieve continuous production. This helps ensure batch-to-batch quality consistency and improves production efficiency, providing food companies with a feasible and scalable solution. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1This is a flowchart illustrating the application method of this invention in maintaining flavor stability during French fry baking. Detailed Implementation

[0022] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0023] Example 1 like Figure 1 As shown, this embodiment provides a method for preparing a flavor-enhancing fermented product, including: (1) Selection of strains: Select microorganisms or enzyme preparations with strong aroma-producing ability, or use a combination of microorganisms and enzyme preparations; (2) Culture medium preparation: Based on carbon source, nitrogen source and phosphate, flavor components are added to prepare a culture medium for cell growth and flavor substance synthesis; (3) Controlled fermentation: Under specific temperature, pH and aerobic conditions, the strains selected in step (1) are inoculated into the culture medium prepared in step (2) for fermentation, and the fermentation endpoint is controlled to accumulate the target flavor precursor substances. (4) Post-processing: The fermentation broth is inactivated, concentrated and homogenized to obtain a slurry-like flavor-enhancing fermentation product.

[0024] In one implementation method, the microorganisms in step (1) of this embodiment include at least one of Saccharomyces cerevisiae and Lactobacillus helveticus; the enzyme preparation includes at least one of flavor protease and hydrolase; or a multi-component synergistic combination of the above-mentioned microorganisms and enzyme preparations is adopted. When using a multi-component synergistic combination, the ratio of each microbial species / enzyme preparation can be adjusted to achieve diversified accumulation of flavor precursor substances and avoid the problem of a single flavor spectrum caused by a single microbial species / enzyme preparation. In this embodiment, a synergistic fermentation system of Saccharomyces cerevisiae and Lactobacillus helveticus is preferred to take into account the aroma-producing ability of yeast and the metabolism of protein and sugar substrates by lactic acid bacteria, thereby expanding the types and proportions of flavor precursors.

[0025] In one embodiment, the carbon source in step (2) of this embodiment includes glucose, and the nitrogen source includes yeast extract; the flavor components include at least one of butter, honey, and wheat gluten. The carbon-to-nitrogen ratio needs to be optimized to a range suitable for cell growth and flavor synthesis during formulation. Butter and honey can provide natural sweet flavor precursors, while wheat gluten can supplement protein and further enrich the types of amino acid flavor precursors.

[0026] The phosphate is used as a buffer salt to stabilize the pH conditions during fermentation; butter, honey and gluten participate in metabolism as flavor substrates, providing lipid and protein substrates to facilitate the production of baking-related flavor precursors.

[0027] In one implementation method, the specific temperature in step (3) of this embodiment is 50-65°C, the pH is 4.5-5.5, and fermentation is carried out under aerobic conditions. During the fermentation process, an aerobic environment is maintained by a ventilation device, and the content of flavor precursors such as amino acids and reducing sugars in the fermentation broth is monitored periodically. Fermentation is stopped when the content reaches its peak value to ensure the maximum accumulation of target flavor precursor substances.

[0028] Aerobic fermentation within the aforementioned temperature and pH window is beneficial for accumulating flavor precursors such as amino acids and reducing sugars. The fermentation endpoint is determined by the accumulation of the target flavor precursors reaching a set threshold, thereby avoiding over-fermentation that could affect the stability of post-processing.

[0029] As one implementation method, the post-processing in step (4) of this embodiment includes: heating and inactivating the fermentation broth, then adjusting the concentration of the fermentation broth by vacuum concentration, and finally homogenizing the fermentation material to make it a uniform slurry. This ensures that the fermentation material is a uniform and fine slurry, avoiding the particle feel from affecting the subsequent spraying effect, and improving the storage stability of the fermentation material. Heat inactivation is used to terminate the activity of microorganisms and enzymes, preventing further reactions in subsequent storage and spraying stages; the slurry system obtained after vacuum concentration and homogenization has good sprayability, making it easy to dilute and transport as needed during the application stage.

[0030] Example 2 This embodiment provides an application method for maintaining flavor stability during French fry baking, including: (1) Pretreatment of French fries: The potato raw materials are processed sequentially to obtain French fries to be baked. The processing includes selection, washing, peeling, cutting into strips, blanching, cooling, quick freezing, and may include a vacuum oil bath step. (2) Spraying of flavoring fermentation product: dilute the flavoring fermentation product prepared by any one of claims 1 to 5 into an aqueous solution, spray it onto the surface of the pretreated French fries and allow it to penetrate shallowly; (3) Low-temperature baking: The coated fries are baked at low temperature to complete the shaping and flavor generation; (4) Subsequent processing: The finished product is obtained by cooling and packaging.

[0031] As one implementation method, the formulation of the flavoring fermentation aqueous solution in step (2) of this embodiment is selected from one of the following two (by mass percentage): Formula 1: 5-40% flavoring fermented ingredients, 5-20% salt powder, 40-90% water; This formula directly combines flavoring fermented ingredients with salt powder, without the need for additional seasoning steps, and is suitable for products that pursue a simple flavor. Salt powder can further enhance the perception of flavor substances in the fermented ingredients. Formula 2: 40-90% flavor-enhancing ferment, 10-60% water. This formula has a higher concentration of ferment, providing a richer base flavor for fries, suitable for occasions where additional flavorings are needed.

[0032] The two formulations can be selected based on product positioning and target flavor intensity, and can also be used separately in different batches to maintain process compatibility and flavor consistency.

[0033] In one implementation method, the amount of the flavor-enhancing fermentation solution sprayed in step (2) of this embodiment is 1.5-5.5% based on the weight of the French fries. A high-pressure atomizing spraying device is used for spraying. During spraying, the conveying speed of the French fries and the pressure of the nozzle are controlled to ensure that the aqueous solution is evenly adhered to the surface of the French fries and penetrates to a depth of 1-2 mm, avoiding the loss of flavor due to mere surface adhesion. This spraying amount range facilitates a balance between flavor intensity and baking shaping, while also promoting uniform adsorption and shallow penetration of the diluted solution on the surface of the French fries.

[0034] As one implementation method, this embodiment includes a flavor enhancement step after step (2) and before step (3): sprinkling flavor seasoning powder onto the surface of the fries, wherein the amount added is 3-7% by weight of the fries. The flavor seasoning powder can be a compound seasoning powder such as honey butter flavor or barbecue flavor, which synergizes with the natural flavor of the aroma-enhancing fermentation product to further enhance the flavor profile of the product. The flavor seasoning powder is preferably in a fine powder form to improve adhesion and reduce the risk of material loss during handling and mixing; this step can be flexibly combined with the spraying formula.

[0035] As one implementation method, the low-temperature baking conditions in step (3) of this embodiment are 120-150℃ and 15-25min. During the baking process, hot air circulation baking is used to ensure that the fries are heated evenly and gently promote the Maillard reaction between the flavor precursors in the aroma-enhancing ferment and the components of the fries themselves, generating rich aromas such as pyrazines and furans, while avoiding the rapid escape of volatile aroma molecules caused by high temperature.

[0036] After spraying, the fries can be left to stand for a short time to promote the uniform adsorption and shallow penetration of the diluted solution on the surface of the fries; after baking, they should be cooled in time and packaged with nitrogen to help maintain flavor stability.

[0037] For implementation methods that include a vacuum oil bath, the flavoring fermentation product spraying should be done after the vacuum oil bath and before low-temperature baking to balance surface adhesion and flavor generation efficiency.

[0038] Example 3 This embodiment provides a method for preparing a flavor-enhancing ferment and its application in maintaining flavor stability during French fry baking, balancing flavor intensity, flavor stability, and clean label requirements. Compared to Embodiments 1 and 2, this embodiment selects different representative values ​​for fermentation conditions, spraying system, baking settings, and powdering ratio for process comparison and verification.

[0039] I. Preparation of Flavor-Enhancing Fermented Products (1) Selection and activation of microbial strains: Multi-strain co-fermentation was adopted. Saccharomyces cerevisiae and Lactobacillus helveticus were mixed at a mass ratio of 1:1 and combined with flavor protease to form a synergistic system of microorganisms and enzymes. To improve the fermentation start-up efficiency, the two strains were inoculated separately into malt extract medium and activated at 30-35℃ for 12-16 hours. Activation was stopped when the OD600 of the bacterial solution reached 0.8-1.0.

[0040] (2) Culture medium preparation and raw material pretreatment: Based on yeast extract (nitrogen source), glucose (carbon source) and phosphate, the carbon-nitrogen ratio was optimized to 25:1; and 5% butter, 3% honey and 2% gluten powder (by mass) were added as flavor substrates. The butter was melted in a water bath at 40-45℃, the honey was filtered through an 80-mesh sieve, and the gluten powder, glucose and yeast extract were premixed evenly to ensure dispersibility and stable ratio.

[0041] (3) Controlled fermentation and pH adjustment: Inoculate the culture medium according to the above combination and carry out fermentation at 55℃, pH 5.0, and aerobic conditions, with continuous aeration to maintain dissolved oxygen. It is recommended to test the amino acid and reducing sugar content in the fermentation broth every 2 hours and end the fermentation when the set endpoint is reached (e.g., the total amount of the two substances reaches the target threshold). If the pH deviates from 4.5 to 5.5 during fermentation, an appropriate amount of citric acid solution or sodium hydroxide solution can be added for fine adjustment.

[0042] (4) Post-processing: The fermentation broth is heated to 88°C for 18 min to inactivate it, and then concentrated under reduced pressure to adjust the solids content (e.g., to about 50%). Then it is homogenized at 25 MPa to obtain a rheologically stable, sprayable slurry-like flavor-enhancing fermentation product. After inactivation, it is advisable to cool it rapidly to 40-45°C before concentration to reduce the thermal impact on the flavor precursors.

[0043] II. Application in French Fry Baking (1) Pretreatment of French fries: Select undamaged fresh potatoes and perform the following steps in sequence: washing, peeling, cutting into strips (e.g., 8mm×8mm), blanching (e.g., 3min in 95℃ hot water), cooling (cooling to near room temperature in ice water), and quick-freezing (e.g., -30℃ for 4h). A vacuum oil bath is set up (e.g., 100℃, vacuum degree of about 0.095MPa, time of 10min) to reduce the oil content. After the vacuum oil bath, centrifugation is performed to remove oil at a speed of 250-300r / min for 2-3min to reduce the surface free oil to the target range (e.g., 8-10%).

[0044] (2) Spraying of flavoring ferment: In this embodiment, the diluted solution is prepared using Formula 2 (mass percentage): 60% flavoring ferment and 40% water. After stirring evenly, the solution is sprayed onto the surface of the French fries using high-pressure atomization. The spraying amount is 3.0% to 3.5% of the weight of the French fries. The conveying speed can be set to about 0.5 m / min and the nozzle pressure to about 0.3 MPa to obtain better coverage and shallow penetration. To improve hygiene and shelf-life stability, the diluted solution can be pasteurized (e.g., 65 to 70°C for 10 to 15 min) and cooled to room temperature before spraying.

[0045] (3) Flavor enhancement (optional): Sprinkle flavor powder after spraying and before baking. In this example, the representative addition amount is 5% (based on the weight of the fries), and let it stand for 5 to 10 minutes to promote adsorption and uniformity.

[0046] (4) Low-temperature baking: Segmented low-temperature baking is used to balance flavor generation and texture. In this example, 130℃ for 10min + 140℃ for 10min (equivalent to a medium temperature and medium time combination of 135℃ and 20min) is used to complete the shaping and flavor generation.

[0047] (5) Subsequent processing and packaging: After baking, cool to room temperature in time and pack and seal with nitrogen. A flavor monitoring program (such as GC-MS monitoring of relative peak area or characteristic indicators of pyrazines and furans) and a sample retention verification process for quality indicators such as appearance, taste, and oil content can be established to evaluate batch consistency and shelf-life flavor retention.

[0048] III. Process Description and Expected Results 1) Flavor precursor supply: The synergistic fermentation and enzyme synergistic preparation strategy, combined with the high solids content of Formula 2 and the median spray volume, can provide a more continuous source of amino acids and reducing sugars for the low-temperature baking stage, and enhance the intensity and spectrum of the Maillard reaction.

[0049] 2) Anchoring and slow release: Polar components such as small molecule peptides in fermentation products can interact non-covalently with aroma molecules, which helps reduce volatilization escape and delay release, thereby improving flavor stability during shelf life.

[0050] 3) Physical barrier and water retention: The proteins and polysaccharides in the fermented product form a dense thin layer on the surface, which helps to control water loss and the escape of volatile components, so as to achieve both a crispy outer layer and a moist inner texture while maintaining a low-fat content.

[0051] 4) Production line adaptability: The key nodes and parameters in this embodiment are representative values ​​within the quantification range. The spraying and baking processes have low requirements for modification of existing production lines and are easy to connect with vacuum oil bath, cooling and packaging stations to achieve automation, continuity and batch-to-batch stability.

[0052] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a flavor-enhancing fermented product, characterized in that: include: (1) Selection of strains: Select microorganisms or enzyme preparations with strong aroma-producing ability, or use a combination of microorganisms and enzyme preparations; (2) Culture medium preparation: Based on carbon source, nitrogen source and phosphate, flavor components are added to prepare a culture medium for cell growth and flavor substance synthesis; (3) Controlled fermentation: Under specific temperature, pH and aerobic conditions, the strains selected in step (1) are inoculated into the culture medium prepared in step (2) for fermentation, and the fermentation endpoint is controlled to accumulate the target flavor precursor substances. (4) Post-processing: The fermentation broth is inactivated, concentrated and homogenized to obtain a slurry-like flavor-enhancing fermentation product.

2. The method according to claim 1, characterized in that: The microorganisms in step (1) include at least one of Saccharomyces cerevisiae and Lactobacillus helveticus; the enzyme preparations include at least one of flavor protease and hydrolase; or a multi-component synergistic combination of the above-mentioned microorganisms and enzyme preparations is used.

3. The method according to claim 1, characterized in that: The carbon source in step (2) includes glucose, and the nitrogen source includes yeast extract; the flavor ingredients include at least one of butter, honey, and wheat gluten.

4. The method according to any one of claims 1 to 3, characterized in that: The specific temperature mentioned in step (3) is 50-65℃, the pH is 4.5-5.5, and fermentation is carried out under aerobic conditions.

5. The method according to any one of claims 1 to 4, characterized in that: The post-processing in step (4) includes: heating and inactivating the fermentation broth, then adjusting the concentration of the fermentation broth by vacuum concentration, and finally homogenizing the fermentation material to make it into a uniform slurry.

6. A method for maintaining flavor stability during French fry baking, characterized in that: include: (1) Pretreatment of French fries: The potato raw materials are processed sequentially to obtain French fries to be baked. The processing includes selection, washing, peeling, cutting into strips, blanching, cooling, quick freezing, and may include a vacuum oil bath step. (2) Spraying of flavoring fermentation product: dilute the flavoring fermentation product prepared by any one of claims 1 to 5 into an aqueous solution, spray it onto the surface of the pretreated French fries and allow it to penetrate shallowly; (3) Low-temperature baking: The coated fries are baked at low temperature to complete the shaping and flavor generation; (4) Subsequent processing: The finished product is obtained by cooling and packaging.

7. The application method according to claim 6, characterized in that: The formulation of the flavoring fermented product aqueous solution in step (2) is selected from one of the following two (by mass percentage): Formula 1: 5-40% flavoring fermented ingredients, 5-20% salt powder, 40-90% water; Formula 2: 40-90% flavoring fermented ingredients, 10-60% water.

8. The application method according to claim 6, characterized in that: The amount of the flavor-enhancing fermented product aqueous solution sprayed in step (2) is 1.5 to 5.5% based on the weight of the French fries.

9. The application method according to any one of claims 6, characterized in that: The process includes a flavor enhancement step after step (2) and before step (3): sprinkling flavor powder on the surface of the fries, wherein the amount added is 3 to 7% by weight of the fries.

10. The application method according to any one of claims 6 to 9, characterized in that: The low-temperature baking conditions described in step (3) are 120-150℃ for 15-25 minutes.

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