Low-salt flavored fermented shredded chili and preparation method thereof

Abstract

The invention discloses low-salt flavored fermented shredded chili and a preparation method thereof, and belongs to the technical field of food processing. Aiming at the problems of long fermentation period, high nitrite content and poor flavor of the existing chili fermentation method, the method comprises the following steps: pretreating chili, shredding and dehydrating; putting the dehydrated shredded chili, auxiliary materials, saline water and activated composite strains into an air pulsating pressure fermentation tank for pulsating pressure staged temperature control fermentation; wherein the composite strain is prepared from lactobacillus plantarum, lactobacillus pentosus and pediococcus pentosaceus according to a specific proportion; and after fermentation, draining, seasoning, standing at low temperature, sterilizing and packaging. The method disclosed by the invention can realize rapid fermentation under a low-salt condition, reduce nitrite and improve flavor, and is suitable for industrial production of high-quality fermented chili products.

Description

Technical Field

[0001] This invention relates to the field of food processing. More specifically, this invention relates to a low-salt flavored fermented chili flakes and its preparation method. Background Technology

[0002] Fermented chili products, as a traditional condiment, are loved by consumers for their unique flavor and appetite-stimulating effects. Traditional chili fermentation methods mostly employ natural fermentation or simple inoculation fermentation, which presents numerous technical challenges in the production process.

[0003] Natural fermentation relies on wild microorganisms attached to the surface of raw materials. These microorganisms are complex and unstable, easily affected by environmental temperature and hygiene conditions, resulting in long fermentation cycles, significant quality fluctuations, and a high risk of bacterial growth, leading to product spoilage or unpleasant flavors. Furthermore, natural fermentation produces higher levels of nitrites, with the peak occurring later, posing a potential safety hazard for consumers.

[0004] To shorten the fermentation cycle and improve product stability, some manufacturers have attempted to directly inoculate lactic acid bacteria for fermentation. However, under conventional static fermentation conditions, the growth rate of lactic acid bacteria is still not ideal, and the accumulation of metabolic products may lead to excessively rapid acidification of the local environment, inhibiting the continued growth of beneficial bacteria. Simultaneously, carbon dioxide easily accumulates at the bottom of the fermenter, creating an anaerobic microenvironment that promotes the proliferation of gas-producing bacteria, affecting fermentation uniformity and product quality.

[0005] With low-salt production becoming a trend in the food industry, reducing salt usage is particularly significant for fermented chili products. However, in traditional processes, salt not only provides a salty taste but, more importantly, inhibits the growth of spoilage bacteria and maintains the texture of raw materials. When the amount of salt used is reduced below a certain level, the product is prone to becoming soft and mushy, and its taste deteriorates, thus limiting the development of low-salt fermented chili products.

[0006] The seasoning process after fermentation also presents technical challenges. To enhance product flavor, it's common practice to add spice oils that have been fried at high temperatures. However, the volatile flavor components in spice oils are sensitive to heat and pressure. Subsequent non-thermal sterilization techniques, such as ultra-high pressure sterilization, can easily lead to flavor loss, resulting in a weakened aroma. Directly added spice oils are unevenly distributed in chili threads, with some areas having an overly strong flavor while others are under-flavored, affecting the consistency of sensory quality. Furthermore, the unsaturated components in spice oils are prone to oxidation and rancidity during storage, shortening the product's shelf life.

[0007] The existence of the above problems makes the preparation process of chili fermentation products that simultaneously achieves rapid fermentation, good texture, rich flavor and long shelf life under low salt conditions a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0008] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0009] To achieve these objectives and other advantages according to the present invention, a method for preparing low-salt flavored fermented chili flakes is provided, comprising the following steps: S1. Select fresh chili peppers, wash them, remove the stems and seeds, and drain off the surface water. S2. Cut the chili peppers into strips, mix them with some salt, rub them together, and let them sit to dehydrate. S3. The dehydrated chili flakes, auxiliary materials, pre-prepared brine, and activated compound microbial inoculum are put into a food-grade air-pulsating pressure fermentation tank for staged temperature-controlled fermentation under pulsed pressure. The compound microbial inoculum consists of Lactobacillus plantarum, Lactobacillus pentosus, and Pediococcus pentosus in a live bacteria ratio of (1.5~2.5):(1.5~2.5):1. The total inoculum amount of the compound microbial inoculum accounts for 4.6%~5.0% of the total mass of the fermentation material. The brine is prepared by mixing residual salt with white sugar, food-grade calcium chloride, and water. S4. After fermentation is complete, remove the chili threads and drain the fermentation liquid; S5. Add the seasoning to the drained chili strips, mix well and let stand at a low temperature; S6. Sterilize the seasoned chili threads and package them.

[0010] Preferably, the pulsed pressure staged temperature-controlled fermentation process includes: Initial fermentation stage: lasts 1-2 days, with the fermentation temperature controlled at 22-25℃; Main fermentation stage: lasts 3-6 days, with fermentation temperature controlled at 20-22℃; Post-ripening stage: lasts 7-8 days, with fermentation temperature controlled at 16-18℃.

[0011] Preferably, during the pulsating pressure staged temperature-controlled fermentation process, the aeration rate is 1~5L / min, the upper limit of the air pressure pulsation is 0.2~0.3MPa, and the lower limit of the air pressure is 0.02~0.04MPa; The pressure pulsation cycle and duration of the pulsed pressure staged temperature-controlled fermentation are controlled according to the fermentation stage: Initial fermentation stage: pressure pulsation cycle is 4~6h, valley pressure maintenance time is 2~3h, peak pressure maintenance time is 2~3h; Main fermentation stage: pressure pulsation cycle is 6~10h, valley pressure maintenance time is 3~5h, peak pressure maintenance time is 3~5h; Post-ripening stage: The pressure pulsation cycle is 5~6 hours, the valley pressure duration is 2.5~3 hours, and the peak pressure duration is 2.5~3 hours.

[0012] Preferably, the ingredients, by weight percentage, are: 70%~75% chili flakes, 4%~4.5% salt, 15%~20% water, 1.2%~1.5% white sugar, 1.5% garlic, 1.0% ginger, 0.3% Sichuan peppercorns, 0.1%~0.3% white vinegar, 0.2% chicken essence, 3%~5% edible oil, and 0.05%~0.1% food-grade calcium chloride.

[0013] Preferably, the chili peppers are cut into strips 4-6 cm long and 2-3 mm wide; the amount of salt used for dehydration is 30% of the total salt in the formula, which is mixed and rubbed with the chili pepper strips and then left to stand for 1-2 hours; when filling the jar, first place some garlic, ginger, and Sichuan peppercorns at the bottom of the jar, then pack the dehydrated chili pepper strips tightly and orderly into the jar, filling it to 10 cm from the rim, and then add the remaining garlic, ginger, and Sichuan peppercorns. Pour the prepared brine into the jar, ensuring that all the chili pepper strips are completely submerged, and then inoculate the activated inoculum into the fermentation tank aseptically according to the formula and inoculation amount.

[0014] Preferably, in step S5, the cooking oil is heated to 180°C and then cooled to 120°C. Spices are added and fried until fragrant, then filtered out to obtain spice oil. The spice oil is cooled to 80°C and mixed with white vinegar and chicken essence in the drained chili strips. The mixture is then left to stand at 0-4°C for 12-24 hours.

[0015] Preferably, the sterilization and packaging steps employ ultra-high pressure instantaneous sterilization, followed by vacuum packaging or nitrogen-filled packaging, and then atmospheric pressure sterilization at 90~95℃ for 10~15 minutes.

[0016] Preferably, during the pulsating pressure staged temperature-controlled fermentation process, at the end of the valley pressure phase of each pressure pulsation cycle, sterile nitrogen gas is introduced into the fermenter at a flow rate of 0.1~0.3 L / min for 5~10 minutes to remove the CO2 accumulated in the fermentation broth, adjust the gas phase composition of the fermentation system, and inhibit the excessive reproduction of anaerobic gas-producing bacteria.

[0017] Preferably, the edible oil added to the seasoning is a microencapsulated spice oil microcapsule; the microcapsules are prepared through the following steps: Mix modified starch and gum arabic at a mass ratio of (4:1) to (3:2), add deionized water to prepare a wall material solution with a solid content of 30% to 40%, stir at 50 to 60°C until completely dissolved, and cool to room temperature for later use. Spicy oil was used as the core material and added to the wall material solution at a core material to wall material mass ratio of 1:3 to 1:4. The solution was then subjected to high-speed shear emulsification at 8000 to 12000 r / min for 10 to 15 min to obtain the primary emulsion. The wall material mass refers to the total solid mass of modified starch and gum arabic. The primary emulsion was subjected to high-pressure homogenization at 40-50 MPa for 2-3 times to obtain a stable emulsion with uniform fineness. The stabilized emulsion was spray-dried at an inlet air temperature of 160-180℃, an outlet air temperature of 80-90℃, and a feed flow rate of 50-100 mL / min to obtain microcapsule powder. Pass the microcapsule powder through a 100-300 mesh sieve.

[0018] The present invention also provides a low-salt flavored fermented chili flakes, which are prepared by the above-described preparation method.

[0019] The present invention includes at least the following beneficial effects By employing a specific ratio of compound microbial strains (Lactobacillus plantarum, Lactobacillus pentosus, and Pediococcus pentosus) combined with pulsed pressure staged temperature-controlled fermentation technology, rapid fermentation can be achieved under low-salt conditions, significantly shortening the fermentation cycle. Simultaneously, it effectively inhibits the growth of unwanted microorganisms, reduces nitrite peaks, and brings them to their earlier appearance, greatly improving the product's food safety. The introduction of pulsed pressure changes during fermentation, coupled with staged temperature control, promotes the dominant growth of lactic acid bacteria and the generation of flavor compounds, resulting in a product rich in various volatile flavor components and umami amino acids, with a rich aroma, harmonious sour and spicy flavor, and delicious taste.

[0020] By introducing sterile nitrogen gas during the valley pressure stage of fermentation, accumulated carbon dioxide is effectively removed, optimizing the fermentation microecological environment, inhibiting the excessive proliferation of anaerobic gas-producing bacteria, and further increasing the number of viable lactic acid bacteria and product quality. The addition of food-grade calcium chloride significantly improves the textural properties of low-salt fermented chili threads, maintaining their crispness and chewiness, thus solving the industry problem of low-salt fermented products easily becoming soft and mushy.

[0021] This product utilizes spice oil microencapsulation technology to encapsulate flavoring oils, protecting flavor components from degradation during ultra-high pressure sterilization and achieving a high retention rate of flavor substances. Simultaneously, the microcapsules provide sustained release during storage, resulting in a uniform and long-lasting flavor, significantly enhanced oxidative stability, and extended shelf life. The final product undergoes sterilization under a combination of ultra-high pressure and normal pressure, meeting national standards for microbiological indicators, ensuring safety and hygiene, and exhibiting excellent sensory quality, thus possessing broad market application prospects.

[0022] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0023] 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.

[0024] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0025] <Example 1> Raw material ratio: Chili flakes: 73kg; Salt: 4.2kg (30%, or 1.26kg, is used for dehydration, and the remaining 2.94kg is used to prepare brine); Drinking water: 17kg; White sugar: 1.3kg; Garlic: 1.5kg (sliced); Ginger: 1.0kg (shredded); Dried Sichuan peppercorns: 0.3kg; White vinegar: 0.2kg; Chicken essence: 0.2kg; Cooking oil: 4kg; Food-grade calcium chloride: 0.08kg; Compound inoculum: 4.8% (based on the total mass of raw materials), of which the ratio of viable Lactobacillus plantarum: Lactobacillus pentosus: Pediococcus pentosus is 2:2:1.

[0026] Preparation steps: 1) Raw material pretreatment: Wash fresh chili peppers with running water, remove stems and seeds, rinse once with drinking water, and place them in a clean stainless steel sieve to drain the surface water naturally.

[0027] 2) Shredding and dehydration: Shred the chili peppers into even, thin strips (4-6 cm long and 2-3 mm wide). Mix 1.26 kg of salt with the chili pepper strips, gently rub, and let stand for 1.5 hours to draw out some moisture.

[0028] 3) Packing and Fermentation: Mix the remaining 2.94 kg of salt, 0.08 kg of food-grade calcium chloride, 1.3 kg of white sugar, and 17 kg of drinking water, stirring until completely dissolved to make brine. Place some garlic slices, ginger shreds, and dried Sichuan peppercorns at the bottom of the fermentation tank. Then, tightly pack the dehydrated chili shreds into the tank, pressing each layer lightly until about 10 cm from the rim. Add the remaining garlic, ginger, and dried Sichuan peppercorns, and slowly pour in the brine to completely submerge the chili shreds. Aseptically inoculate the activated compound microbial culture into the tank at an inoculation rate of 4.8%.

[0029] Initiate the pulsed pressure staged temperature-controlled fermentation program: Initial fermentation stage (1~2d): temperature 23℃, aeration rate 3 L / min, pressure pulsation cycle 5 h (valley pressure 0.03MPa maintained for 2.5 h, peak pressure 0.25 MPa maintained for 2.5 h).

[0030] Main fermentation stage (3~6d): temperature 21℃, aeration rate 3 L / min, pressure pulsation cycle 8 h (valley pressure 0.03 MPa maintained for 4 h, peak pressure 0.25 MPa maintained for 4 h).

[0031] Post-ripening stage (7-8 days): temperature 17℃, ventilation rate 3 L / min, pressure pulsation period 5.5 h (valley pressure 0.03 MPa maintained for 2.75 h, peak pressure 0.25 MPa maintained for 2.75 h).

[0032] At the end of fermentation, the chili threads are tangy and fragrant, without any citrus flowers, and the juice is clear.

[0033] 4) Unloading and draining: Remove the chili threads and place them in a sterilized sieve to allow the fermentation liquid to drain naturally for 5 hours.

[0034] 5) Seasoning and mixing: Heat 4 kg of cooking oil to 180℃, turn off the heat and cool to 120℃. Add 80g of Sichuan peppercorns (2% of the weight of cooking oil) and 80g of star anise (2% of the weight of cooking oil) (Sichuan peppercorns and star anise are not included in the raw material weight). Fry until fragrant, filter out the spices, and obtain the aromatic oil.

[0035] Add 0.2 kg of white vinegar and 0.2 kg of chicken bouillon to the drained chili threads, then pour in the cooled spice oil (80°C) evenly and mix quickly. Cover with plastic wrap and let stand at 0-4°C for 18 hours.

[0036] 6) Sterilization and packaging: The seasoned chili threads are subjected to ultra-high pressure instantaneous sterilization (pressure 600 MPa, pressure held for 5 min), then vacuum packaged, sterilized at 90℃ and normal pressure for 12 min, and rapidly cooled to obtain the finished product.

[0037] Comparative Example 1: Natural Fermentation No compound microbial strains were added, and no pulsed pressure treatment was performed; otherwise, the process was the same as in Example 1. Chili threads were placed into a ceramic jar using traditional methods, submerged in salt water, and the jar was sealed with water. The jar was then allowed to ferment naturally at room temperature (20-25°C) for 15 days until the pH ≤ 4.0. Subsequent seasoning and sterilization steps were the same as in Example 1.

[0038] Comparative Example 2: Conventional inoculation and fermentation The compound microbial strain was inoculated (in the same proportion as in Example 1), but conventional static fermentation was used (without aeration or pressurization), with the temperature controlled at a constant 22°C throughout the process, and the fermentation time was 10 days until the pH ≤ 4.0. The rest was the same as in Example 1.

[0039] Comparative Example 3: Calcium Chloride-Free No food-grade calcium chloride was added; otherwise, it was the same as in Example 1.

[0040] <Product Testing Methods> Total acid (calculated as lactic acid): Samples were taken after the finished product was packaged and determined by acid-base titration according to GB 12456-2021.

[0041] pH value: Samples were taken after the finished product was packaged and measured using a pH meter (FE28 type, Mettler Toledo) in accordance with GB 5009.237-2016.

[0042] Organic acid composition: Samples were taken after the finished product was packaged and determined according to the high performance liquid chromatography method in GB 5009.157-2016. High performance liquid chromatograph: 1260 Infinity model, Agilent Technologies, USA.

[0043] Volatile flavor compounds: Samples were taken after the finished product was packaged and analyzed using HS-SPME-GC-MS with a gas chromatography-mass spectrometry system of model 7890A-5975C, Agilent Technologies, USA.

[0044] Free amino acids: Samples were taken after the finished product was packaged and determined according to the automatic amino acid analyzer method in GB 5009.124-2016. The automatic amino acid analyzer was a L-8900 model manufactured by Hitachi, Japan.

[0045] Lactic acid bacteria viable count: After fermentation is completed (i.e. before leaving the tank), aseptically sampled and determined according to the plate count method of GB 4789.35-2016.

[0046] Nitrite: Determined according to the naphthylethylenediamine hydrochloride method in GB 5009.33-2016. Sampling procedure: Samples were taken at regular intervals on day 0 (immediately after filling the fermenter), day 1, day 2, day 3, day 4, day 5, day 6, day 7, and day 8 of fermentation. 50 mL of fermentation broth was taken from each of the top, middle, and bottom layers of the fermenter each time, and mixed thoroughly. Three parallel samples were prepared at each time point, and the average value was taken. The highest value among all detection time points was recorded as the nitrite peak value, and the time of occurrence was recorded.

[0047] Texture properties: Samples were taken after finished product packaging and tested using a TA.XT Plus texture analyzer with a P / 36R cylindrical probe in TPA mode (two compressions). Test parameters: pre-test velocity 1.0 mm / s, test velocity 0.5 mm / s, post-test velocity 1.0 mm / s, compression ratio 50%, trigger force 5 g. Hardness (maximum force during the first compression, g), brittleness (force at break during the first compression, g), and chewiness (hardness × cohesion × elasticity, g) were recorded.

[0048] Total bacterial count: Samples were taken after the finished product was packaged and determined according to the plate count method of GB 4789.2-2022.

[0049] Coliform bacteria: Samples were taken after the finished product was packaged and determined according to the MPN counting method in GB 4789.3-2016.

[0050] Pathogenic bacteria (Salmonella, Staphylococcus aureus): Samples were taken after the finished product was packaged and tested according to GB 4789.4-2016 and GB 4789.10-2016, respectively.

[0051] Sensory evaluation: Samples were taken after the finished product was packaged. An evaluation panel of 10 professionally trained sensory evaluators (aged 22-45, half male and half female, without taste / olfactory impairments) was formed. Evaluators refrained from smoking, eating, and using scented cosmetics for one hour prior to the evaluation. Samples were randomly coded and tested blindly. After evaluating each sample, evaluators rinsed their mouths with water for 3 minutes. Evaluators independently scored the five indicators—appearance, color, aroma, taste, and texture (brittleness)—according to the scoring criteria in Table 1. Each indicator was scored out of 10 points, and the average score was used as the individual indicator score. The sum of the five scores was the total score.

[0052] Table 1 <Test Results> The main physicochemical and microbiological indicators are shown in Table 2: Table 2 The textural properties are shown in Table 3: Table 3 Other microbiological indicators are shown in Table 4: Table 4 *Note 1 Reference values ​​are given to GB 2714-2015, the national food safety standard for pickled vegetables.

[0053] *Note 2 Example 1: The total bacterial count met the strict control target of ≤1000 CFU / g (enterprise standard). The national standard GB2714-2015 does not have a specific limit on the total bacterial count of pickled vegetables, but mainly controls pathogenic bacteria and coliform bacteria.

[0054] The types of volatile flavor compounds and the quantities of key aroma compounds are shown in Table 5: Table 5 The content of free amino acids is shown in Table 6: Table 6 Sensory evaluation scores (out of 10) are shown in Table 7: Table 7 As shown in Tables 2-7: Regarding fermentation efficiency and safety, the fermentation cycle of Example 1 of this invention was 8 days, significantly shorter than that of Comparative Example 1 (15 days) and Comparative Example 2 (10 days), indicating that pulsed pressure combined with segmented temperature control can effectively accelerate the fermentation process; in Example 1, the viable count of lactic acid bacteria after fermentation reached 2.5 × 10⁻⁶. 8 The CFU / g level was significantly higher than that of Comparative Example 1 (natural fermentation), indicating that inoculation with the compound strain can establish lactic acid bacteria dominance and inhibit other bacteria. Furthermore, the peak nitrite level in Example 1 (8.8 mg / kg) was much lower than that in Comparative Example 1 (22.3 mg / kg), and the peak occurred earlier (on day 3), demonstrating that the method of this invention can effectively reduce the risk of nitrite.

[0055] Regarding textural properties (preservation and crispness enhancement), the hardness (1850.3g) and chewiness (720.5g) of Example 1 were significantly higher than those of Comparative Example 1 (hardness 1023.5g, chewiness 385.3g), Comparative Example 2 (hardness 1325.7g, chewiness 502.1g), and Comparative Example 3 (hardness 1286.4g, chewiness 483.5g). The crispness (285.6g) of Example 1 was significantly higher than that of Comparative Example 1 (165.4g) and Comparative Example 3 (201.2g). This indicates that the addition of calcium chloride (Comparative Example 3) and the pulsed pressure fermentation process (Comparative Examples 1 and 2) have a synergistic effect on maintaining the textural properties of the product, effectively solving the industry problem of low-salt fermented products being prone to softening and spoilage.

[0056] Regarding microbiological indicators (safety), the total bacterial count (120 CFU / g) of the product in Example 1 met the stringent control standards and was significantly lower than that of Comparative Example 1 (1500 CFU / g) and Comparative Example 2 (420 CFU / g), indicating that the fermentation process and sterilization method of this invention can effectively control microbial contamination. The coliform count in Example 1 was <3.0 MPN / 100g, and no pathogenic bacteria were detected, fully complying with the requirements of GB 2714-2015 "National Food Safety Standard for Pickled Vegetables," demonstrating high product safety.

[0057] Regarding volatile flavor compounds, Example 1 detected 86 compounds, with esters, alcohols, and olefins appearing in greater quantities than in the comparative examples. It also contained 12 key aroma compounds (OAV > 1), contributing a rich fermented aroma to the product. The umami amino acid content in Example 1 reached 985.36 μg / mL, 1.88 times that of the comparative example, demonstrating the contribution of fermentation to enhancing umami. In terms of overall sensory evaluation, Example 1 significantly outperformed all the comparative examples, particularly in aroma, taste, and texture.

[0058] In summary, this invention achieves rapid fermentation, rich flavor, crisp texture, and safety and hygiene under low-salt conditions through compound microbial strains, segmented temperature-controlled fermentation with pulsed pressure, and optimized auxiliary materials. All product indicators meet national food safety standards.

[0059] <Example 2> The process is basically the same as in Example 1, except that: during the pulsating pressure staged temperature-controlled fermentation process, at the end of the valley pressure phase of each pressure pulsation cycle, sterile nitrogen gas is introduced into the fermenter at a flow rate of 0.2 L / min for 8 minutes to remove the CO2 accumulated in the fermentation broth, adjust the gas phase composition of the fermentation system, and inhibit the excessive reproduction of anaerobic gas-producing bacteria.

[0060] <Example 3> The process is essentially the same as in Example 2, except that the edible oil added to the seasoning is a microencapsulated spice oil microcapsule; the microcapsules are prepared through the following steps: Modified starch and gum arabic were mixed at a mass ratio of 4:1, and deionized water was added to prepare a wall material solution with a solid content of 35%. The solution was stirred at 55°C until completely dissolved, and then cooled to room temperature for later use. Spicy oil was used as the core material and added to the wall material solution at a core material to wall material mass ratio of 1:3.5. The solution was then subjected to high-speed shear emulsification at 10000 r / min for 12 min to obtain the primary emulsion. The wall material mass refers to the total solid mass of modified starch and gum arabic. The primary emulsion was subjected to high-pressure homogenization twice at 45 MPa to obtain a stable emulsion with uniform fineness. The stabilized emulsion was spray-dried at an inlet air temperature of 170°C, an outlet air temperature of 85°C, and a feed flow rate of 80 mL / min to obtain microcapsule powder. The microcapsule powder was passed through a 200-mesh sieve to collect microcapsule particles with an average particle size of approximately 80–120 μm. For seasoning, the microcapsule powder was directly mixed with the drained chili threads in an amount equivalent to the weight of the edible oil in the original recipe.

[0061] <Product Testing Methods> CO2 concentration determination: On days 0, 2, 4, 6, and 8 of fermentation, 50 mL of fermentation broth was taken from each of the top, middle, and bottom layers of the fermenter and mixed thoroughly. The dissolved CO2 concentration in the fermentation broth was determined by gas chromatography (refer to GB 5009.226-2016). Three parallel samples were set for each time point, and the average value was taken.

[0062] Lactic acid bacteria viable count: After fermentation is completed (i.e. before leaving the tank), aseptically sampled and determined according to the plate count method of GB 4789.35-2016.

[0063] Gas-producing bacteria (Enterobacteriaceae): Aseptically sampled after fermentation (i.e. before leaving the tank) and determined according to the plate count method of GB 4789.41-2016.

[0064] Retention rate of characteristic flavor compounds in spice oils: 10 g of each of the flavored samples from Examples 1, 2, and 3, and the samples after ultra-high pressure sterilization, were extracted from the volatile components of the spice oils using simultaneous distillation extraction (SDE). The extracts were dried over anhydrous sodium sulfate and concentrated to 1 mL. GC-MS analysis: Gas chromatography-mass spectrometry (GC-MS) was used (7890A-5975C, Agilent Technologies, USA), with an HP-5MS column (30 m × 0.25 mm × 0.25 μm); temperature program: 40℃ for 2 min, increased to 200℃ at 5℃ / min, then increased to 250℃ at 10℃ / min and held for 5 min; injection port temperature 250℃, carrier gas He, flow rate 1.0 mL / min; mass spectrometry conditions: EI source, 70 eV, scan range 35–450 amu. The relative content of each component was calculated using the peak area normalization method. Characteristic flavor compounds were selected as limonene and linalool, and their retention rates were calculated as follows: Retention rate (%) = (content after sterilization / content before sterilization) × 100%. The total flavor compound retention rate was calculated based on the total area of ​​all detected volatile components.

[0065] Sensory evaluation of flavor uniformity and persistence: Samples were taken after the finished product was packaged. The evaluation team consisted of 10 professionally trained sensory evaluators (aged 22-45, half male and half female, without taste / olfactory impairments). Evaluators refrained from smoking, eating, and using scented cosmetics within one hour prior to the evaluation. Evaluation indicators included: Aroma intensity upon opening: Immediately after opening, the aroma was smelled and scored from 0 to 10 (0 = no aroma, 10 = extremely strong aroma); Flavor uniformity: Ten chili threads were randomly selected from each sample, and each evaluator tasted and independently scored the flavor intensity (0-10 points) of each thread. The coefficient of variation (CV%) of the scores for the ten chili threads was calculated; a lower CV% indicates better uniformity; Flavor persistence: After chewing the sample, the duration (in seconds) of flavor perception in the mouth was recorded, and the average value was taken. Samples were randomly coded, and a blind test method was used. After evaluating each sample, the evaluators rinsed their mouths with water for 3 minutes at intervals.

[0066] Storage stability: The finished products of the three embodiments were placed in a constant temperature and humidity chamber at 37°C and 75% relative humidity for 30 days. Samples were taken on days 0, 10, 20, and 30, and the total peak area of ​​characteristic flavor substances in the spice oil was determined by the GC-MS method described above. The retention rate of characteristic flavor substances in the spice oil was calculated with day 0 as 100%. The peroxide value was tested according to GB 5009.227-2016 "Determination of Peroxide Value in Food". The oil was extracted and titrated, and the results were expressed as meq / kg.

[0067] <Test Results> The results of CO2 concentration and microbial community changes during fermentation are shown in Table 8: Table 8 The retention rates of characteristic flavor compounds before and after ultra-high pressure sterilization are shown in Table 9. Table 9 The sensory evaluation results for flavor uniformity and persistence are shown in Table 10: Table 10 The results of flavor retention and peroxide value changes during storage are shown in Table 11: Table 11 As shown in Tables 8-11: In Examples 2 and 3, after nitrogen was introduced during the valley pressure stage, the CO2 concentration in the fermentation broth was significantly lower than that in Example 1. At the same time, the number of gas-producing bacteria decreased, while the number of viable lactic acid bacteria increased slightly. This indicates that nitrogen introduction effectively inhibited the reproduction of anaerobic gas-producing bacteria and optimized the fermentation microecology.

[0068] In Example 3, after microencapsulation, the damage to the spice oil caused by ultra-high pressure sterilization was significantly reduced, and the flavor substance retention rate was as high as 94% or more, which was much higher than that of Examples 1 and 2 where the ingredients were directly added. This proves that microcapsules effectively protect the flavor components under ultra-high pressure.

[0069] Example 3 showed higher aroma intensity, significantly improved flavor uniformity (CV of only 9.8%), and almost doubled persistence, demonstrating that microcapsules achieve uniform distribution and slow release of flavor substances.

[0070] The microcapsules in Example 3 continuously protected the spice oil during storage, maintaining a flavor retention rate of 76% after 30 days with extremely low oxidation (POV 3.1 meq / kg). In contrast, Examples 1 and 2 showed significant flavor loss, with Example 1 exceeding the POV limit (based on GB2716-2018 "Vegetable Oils," the peroxide value limit for edible vegetable oils (including flavoring oils) is typically ≤0.25g / 100g, which translates to approximately 9.85 meq / kg). This demonstrates that microencapsulation technology significantly extends product shelf life.

[0071] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A method for preparing low-salt flavored fermented chili threads, characterized in that, Includes the following steps: S1. Select fresh chili peppers, wash them, remove the stems and seeds, and drain off the surface water. S2. Cut the chili peppers into strips, mix them with some salt, rub them together, and let them sit to dehydrate. S3. The dehydrated chili flakes, auxiliary materials, pre-prepared brine, and activated compound microbial inoculum are put into a food-grade air-pulsating pressure fermentation tank for staged temperature-controlled fermentation under pulsed pressure. The compound microbial inoculum consists of Lactobacillus plantarum, Lactobacillus pentosus, and Pediococcus pentosus in a live bacteria ratio of (1.5~2.5):(1.5~2.5):

1. The total inoculum amount of the compound microbial inoculum accounts for 4.6%~5.0% of the total mass of the fermentation material. The brine is prepared by mixing residual salt with white sugar, food-grade calcium chloride, and water. S4. After fermentation is complete, remove the chili threads and drain the fermentation liquid; S5. Add the seasoning to the drained chili strips, mix well and let stand at a low temperature; S6. Sterilize the seasoned chili threads and package them.

2. The preparation method according to claim 1, characterized in that, The pulsed pressure staged temperature-controlled fermentation process includes: Initial fermentation stage: lasts 1-2 days, with the fermentation temperature controlled at 22-25℃; Main fermentation stage: lasts 3-6 days, with fermentation temperature controlled at 20-22℃; Post-ripening stage: lasts 7-8 days, with fermentation temperature controlled at 16-18℃.

3. The preparation method according to claim 2, characterized in that, During the pulsating pressure staged temperature-controlled fermentation process, the aeration rate is 1~5L / min, the upper limit of the air pressure pulsation is 0.2~0.3MPa, and the lower limit of the air pressure is 0.02~0.04MPa; The pressure pulsation cycle and duration of the pulsed pressure staged temperature-controlled fermentation are controlled according to the fermentation stage: Initial fermentation stage: pressure pulsation cycle is 4~6h, valley pressure maintenance time is 2~3h, peak pressure maintenance time is 2~3h; Main fermentation stage: pressure pulsation cycle is 6~10h, valley pressure maintenance time is 3~5h, peak pressure maintenance time is 3~5h; Post-ripening stage: The pressure pulsation cycle is 5~6 hours, the valley pressure duration is 2.5~3 hours, and the peak pressure duration is 2.5~3 hours.

4. The preparation method according to claim 1, characterized in that, The ingredients, by weight percentage, are as follows: chili flakes 70%~75%, salt 4%~4.5%, water 15%~20%, white sugar 1.2%~1.5%, garlic 1.5%, ginger 1.0%, Sichuan peppercorns 0.3%, white vinegar 0.1%~0.3%, chicken essence 0.2%, cooking oil 3%~5%, and food-grade calcium chloride 0.05%~0.1%.

5. The preparation method according to claim 4, characterized in that, Cut the chili peppers into strips 4-6 cm long and 2-3 mm wide. Use 30% of the total salt in the recipe for dehydration. Mix and rub the chili pepper strips with the salt and let them stand for 1-2 hours. When filling the jar, first put some garlic, ginger, and Sichuan peppercorns at the bottom of the jar. Then, pack the dehydrated chili pepper strips tightly and orderly into the jar, filling it to 10 cm from the rim. Add the remaining garlic, ginger, and Sichuan peppercorns. Pour the prepared brine into the jar, ensuring that all the chili pepper strips are completely submerged. Then, inoculate the activated bacteria into the fermentation tank according to the ratio and inoculation amount using aseptic techniques.

6. The preparation method according to claim 1, characterized in that, In step S5, the cooking oil is heated to 180°C and then cooled to 120°C. Spices are added and fried until fragrant, then filtered out to obtain spice oil. The spice oil is cooled to 80°C and mixed with white vinegar and chicken essence in the drained chili strips. The mixture is then left to stand at 0-4°C for 12-24 hours.

7. The preparation method according to claim 1, characterized in that, The sterilization and packaging steps employ ultra-high pressure instantaneous sterilization, followed by vacuum packaging or nitrogen-filled packaging, and then atmospheric pressure sterilization at 90~95℃ for 10~15 minutes.

8. The preparation method according to claim 3, characterized in that, During the pulsating pressure staged temperature-controlled fermentation process, at the end of the valley pressure phase of each pressure pulsation cycle, sterile nitrogen gas is introduced into the fermenter at a flow rate of 0.1~0.3 L / min for 5~10 minutes to remove the CO2 accumulated in the fermentation broth, adjust the gas phase composition of the fermentation system, and inhibit the excessive reproduction of anaerobic gas-producing bacteria.

9. The preparation method according to claim 6, characterized in that, The edible oil added to the seasoning is a microencapsulated spice oil microcapsule; the microcapsules are prepared through the following steps: Mix modified starch and gum arabic at a mass ratio of (4:1) to (3:2), add deionized water to prepare a wall material solution with a solid content of 30% to 40%, stir at 50 to 60°C until completely dissolved, and cool to room temperature for later use. Spicy oil was used as the core material and added to the wall material solution at a core material to wall material mass ratio of 1:3 to 1:

4. The solution was then subjected to high-speed shear emulsification at 8000 to 12000 r / min for 10 to 15 min to obtain the primary emulsion. The wall material mass refers to the total solid mass of modified starch and gum arabic. The primary emulsion was subjected to high-pressure homogenization at 40-50 MPa for 2-3 times to obtain a stable emulsion with uniform fineness. The stabilized emulsion was spray-dried at an inlet air temperature of 160-180℃, an outlet air temperature of 80-90℃, and a feed flow rate of 50-100mL / min to obtain microcapsule powder. Pass the microcapsule powder through a 100-300 mesh sieve.

10. A low-salt flavored fermented chili flakes, characterized in that, It is prepared by any one of claims 1 to 9.

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