A sulfur-free hydrogen-rich long-acting preservation process for bamboo shoots

Abstract

The application discloses a sulfur-free hydrogen-rich long-acting fresh-keeping process for bamboo shoots and belongs to the technical field of clean fresh-keeping processing of bamboo shoots. The process comprises the following steps: after fresh bamboo shoots are dry-salted for 15 days by using a special dry-salting powder, the bamboo shoots are directly put into a pool without water washing; hydrogen-rich water with hydrogen solubility of 1.6 ppm and ORP of 600 mV is used as a base to prepare a fresh-keeping solution by compounding edible salt, anhydrous citric acid, sodium phytate, D-sodium erythorbate, R-polysaccharide, potassium cinnamate, nisin and natamycin; the bamboo shoots are soaked in a standardized fixed pool at normal temperature in a sealed mode; and periodical maintenance is carried out. The whole process is sulfur-free, the color of the bamboo shoots is natural, the bamboo shoots are not blackened and acidified, the meat of the bamboo shoots is crisp and tender, there is no residual sulfur dioxide, and a desulfurization process is not needed, so that the process can be directly converted into a workshop quasi-standard operation procedure.

Description

Technical Field

[0001] This invention belongs to the field of bamboo shoot cleaning, preservation and processing technology, and specifically relates to a sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots. Background Technology

[0002] After bamboo shoots are harvested, polyphenol oxidase and metal ions easily induce browning. Simultaneously, the high moisture and nutrient-rich substrate promotes the growth of mold, yeast, and acid-producing spores. To extend the shelf life of bamboo shoots, traditional processes commonly employ soaking in sodium metabisulfite for color protection and antibacterial action. While sulfur-based agents offer stable short-term color protection and antibacterial effects, they suffer from three major drawbacks:

[0003] (1) The bamboo shoots are unnaturally pale and lose their natural color, which seriously affects the appearance of the finished product.

[0004] (2) The storage process continuously releases sulfur dioxide with an irritating odor. Before further processing, multiple stages of desulfurization and rinsing with clean water must be added, which greatly increases the cost of water, labor and time.

[0005] (3) Sulfur dioxide residue in bamboo shoots accumulates continuously over time and is very likely to exceed the limits of GB2760 and 50mg / kg for export food, which cannot meet the requirements of clean label pre-prepared dishes and foreign trade orders.

[0006] Existing sulfur-free bamboo shoot preservation technologies still have four major drawbacks:

[0007] (1) The storage period is short. The conventional pure water compound sulfur-free system can only be stored at room temperature for 3 to 6 months. After 6 months, the reducing components decay rapidly, the bamboo shoots turn black, and the water becomes acidic and turbid.

[0008] (2) The antioxidant system is simple and lacks periodic efficacy enhancement schemes, resulting in a sharp decline in antibacterial and color-protecting abilities in the middle and late stages.

[0009] (3) The dry curing and shaping process is separated from the soaking and preservation process. The protective film on the surface of the bamboo shoot is lost due to water washing, and the crispness decreases significantly after long-term soaking.

[0010] (4) There are no standardized mass production bubble pool parameters, and laboratory test data cannot be directly scaled up to the production of large-scale bubble pools in the workshop.

[0011] Currently, the industry lacks an integrated bamboo shoot preservation process that is compatible with large-scale fixed soaking tanks in factories, operates at natural ambient temperature, lasts for 12 months, is sulfur-free throughout the process, and includes graded maintenance and control.

[0012] Therefore, addressing the shortcomings of the existing technologies has become the focus of efforts for those skilled in the field. Summary of the Invention

[0013] The purpose of this invention is to provide a sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots, which can completely solve the shortcomings of the existing technology.

[0014] The objective of this invention is achieved through the following technical solution:

[0015] A sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots includes the following steps:

[0016] (1) Dry curing process: Freshly harvested bamboo shoots are mixed with dry curing powder and dry cured at 20-32℃ for 15 days. After dry curing, the bamboo shoot raw materials are not washed or soaked in water, but directly sent to the soaking pool for preservation. The dry curing powder contains at least edible salt, sodium D-isoascorbate, sodium phytate and R-polysaccharide. The dry curing powder may also add one or more of the following components according to the bamboo shoot variety and whiteness requirements:

[0017] L-cysteine ​​hydrochloride: The addition amount is 0.01-0.03 kg based on 25 kg of fresh bamboo shoots, which acts as a reducing agent to synergistically inhibit polyphenol oxidase activity;

[0018] Food-grade lactic acid powder: The addition amount is 0.05-0.10 kg based on 25 kg of fresh bamboo shoots, used to lower the pH of the dry curing environment and enhance the activity of the reducing agent;

[0019] Anhydrous citric acid: The addition amount is 0.02-0.05 kg based on 25 kg of fresh bamboo shoots, used to adjust the pH of the dry-curing environment;

[0020] Tea polyphenols: The addition amount is 0.05-0.10 kg based on 25 kg of fresh bamboo shoots, as a natural antioxidant.

[0021] For the preferred combinations of the above components, their applicable raw materials, and the expected whiteness effect, please refer to the three exemplary formulations T1, T2, and T3 in the specific embodiments of this specification.

[0022] (2) Pretreatment of the soaking pool: Inject hydrogen-rich water with 1.6 ppm of dissolved hydrogen into the standardized soaking pool and soak for 30 minutes, then drain and clean for later use.

[0023] (3) Preparation of preservation solution: Using hydrogen-rich water with 1.6 ppm hydrogen and ORP-600 mV as the base, add the following components in the following order: ① Dissolve edible salt by stirring, ② Adjust pH with anhydrous citric acid, ③ Sodium phytate, ④ Sodium D-isoascorbate, ⑤ R-polysaccharide by stirring at a constant speed to form a film, ⑥ Potassium cinnamate and nisin, ⑦ Natamycin; after adding all the components, stir at a low speed for 15 min until there is no precipitate to obtain sulfur-free hydrogen-rich preservation solution;

[0024] The sulfur-free hydrogen-rich preservative solution is composed of the following components in parts by weight: 100 parts hydrogen-rich water, 4.8 parts edible salt, 0.22 parts anhydrous citric acid, 0.08 parts sodium phytate, 0.05 parts sodium D-isoascorbate, 0.10 parts R-polysaccharide, 0.07 parts potassium cinnamate, 0.02 parts nisin, and 8 mg / kg natamycin.

[0025] (4) Sealing in the pool: Spread the dried pickled bamboo shoots evenly in the soaking pool, and inject the sulfur-free hydrogen-rich preservation liquid prepared in step (3). The mass ratio of dried pickled bamboo shoots to sulfur-free hydrogen-rich preservation liquid is 1:2. The sulfur-free hydrogen-rich preservation liquid completely submerges the material, and the liquid level is 8-10cm above the bamboo shoot pile. Cover the pool opening with a double-layer light-proof and sealed tarpaulin (allowing a small amount of gas exchange to prevent the formation of an anaerobic environment). Store in a sealed container in a light-proof and ventilated workshop at 20-32℃.

[0026] (5) Periodic maintenance: Periodic maintenance is carried out according to five time gradients: weekly, monthly, quarterly, semi-annually and year-end.

[0027] Preferably, the dry-cured powder is dry-cured formula T1, which is used for high-whiteness small-diameter bamboo shoots from high mountains. The formula is as follows: based on 25kg of fresh bamboo shoots, 5.00kg of edible salt, 0.125kg of sodium D-isoascorbate, 0.02kg of L-cysteine ​​hydrochloride, 0.05kg of sodium phytate, 0.075kg of food-grade lactic acid powder, and 0.025kg of R-polysaccharide.

[0028] Preferably, the dry-cured powder is dry-cured formula T2, used for the large-scale deep processing of Yingde bamboo shoots with medium whiteness requirements. Its formula is as follows: based on 25kg of fresh bamboo shoots, 5.00kg of edible salt, 0.125kg of sodium D-isoascorbate, 0.0125kg of L-cysteine ​​hydrochloride, 0.03kg of sodium phytate, 0.04kg of anhydrous citric acid, and 0.025kg of R-polysaccharide.

[0029] Preferably, the dry-curing powder is dry-curing formula T3, used for the deep processing of Yingde bamboo shoots with low whiteness requirements. Its formula is as follows: based on 25kg of fresh bamboo shoots, 5.00kg of edible salt, 0.075kg of sodium D-isoascorbate, 0.03kg of sodium phytate, 0.075kg of tea polyphenols, 0.03kg of anhydrous citric acid, and 0.025kg of R-polysaccharide.

[0030] Preferably, the standardized soaking pool has individual pool dimensions of 3m long × 2.8m wide × 2.5m deep, with a total volume of 21m³. 3 The effective liquid filling depth is 2.2m, with a 0.3m reserved sealing safety space, and the effective preservation liquid volume per tank is 18.48m³. 3 The maximum capacity of a single pool is 9.5 tons of dried pickled bamboo shoots.

[0031] Preferably, the periodic maintenance includes:

[0032] (1) Weekly maintenance: Test the salinity and pH of the preservation solution. When the solution is insufficient, replenish the sulfur-free hydrogen-rich preservation solution prepared in step (3). Visually observe the color of the bamboo shoots, the surface mold, the turbidity of the water and the sour taste.

[0033] (2) Monthly maintenance: Start the circulating pump to circulate the water for 10 minutes. When a white film appears, add natamycin. When the pH rises, use citric acid to adjust it back to 4.2-4.6 and take samples for initial microbial screening.

[0034] (3) Quarterly maintenance: Add 0.02% sodium D-isoascorbate and 0.02% potassium cinnamate by weight of the total preservative solution;

[0035] (4) Maintenance every six months: submit samples for total bacterial count, mold and yeast tests, adjust the dosage of nisin and natamycin based on the test data, and supplement with R-polysaccharide;

[0036] (5) Year-end maintenance: When the storage period is 12 months, open the tank to test sensory indicators, physicochemical indicators, microbiological indicators, texture indicators and color indicators.

[0037] Preferably, the sulfur-free hydrogen-rich preservative solution does not contain sodium metabisulfite or sodium bisulfite.

[0038] Preferably, the bamboo shoots are high-altitude small-path bamboo shoots or Yingde bamboo shoots.

[0039] Preferably, the dried pickled bamboo shoots in step (4) are laid out evenly without being squeezed or suspended.

[0040] Preferably, the process achieves 12-month long-term preservation of bamboo shoots at room temperature (20-32℃), with no detectable sulfur dioxide residue in the bamboo shoots, total bacterial count in the water controlled below 100 CFU / mL throughout the process, and no detectable molds or yeasts.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] (1) The sulfur-free anti-corrosion system based on hydrogen-rich reduction substrate replaces sulfite, leaving no sulfur dioxide residue. The color of the bamboo shoots is natural and controllable, eliminating the need for additional desulfurization and rinsing processes, saving water and labor, and meeting the requirements for export and pre-prepared food cleaning labels. Multiple reduction, chelation and biological antibacterial synergistic effects effectively block enzymatic browning, metal ion-catalyzed browning and microbial deterioration.

[0043] (2) Fixed standardized bubble tank size, strict feeding sequence and periodic maintenance, complete and clear process parameters, can be directly converted into standardized workshop operation procedures without secondary scale-up and debugging, truly realizing the seamless connection between laboratory technology and industrial mass production.

[0044] (3) By adopting a phased dynamic reinforcement and antibacterial component technical strategy, the technical problems of drug efficacy decay and blackening and sourness in the middle and late stages of long-term storage of sulfur-free system are effectively solved, ensuring stable preservation effect throughout the 12-month cycle.

[0045] (4) No need to use constant temperature cold storage equipment. It can achieve 12 months of airtight preservation by relying on the natural ambient temperature of the factory at 20-32℃, which greatly reduces the energy consumption cost of storage and is suitable for the actual production conditions of bamboo shoot production areas in southern my country. Detailed Implementation

[0046] Exemplary embodiments of the present disclosure will now be described in more detail. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0047] Standardized experimental conditions: Standard soaking tank 3m×2.8m×2.5m, loaded with 9.5t of dried pickled bamboo shoots, solid-liquid ratio 1:2, hydrogen-rich water ORP-600mV, dissolved hydrogen 1.6ppm. During the soaking tank storage period, the tank was stored in the factory at a normal temperature of 22~30℃, away from light, and a five-level maintenance system was strictly implemented.

[0048] Example 1

[0049] This embodiment illustrates the process and effect of using dry-curing formula T1 to preserve the freshness of small-diameter bamboo shoots from high mountains.

[0050] (1) Dry curing process: Take 25kg of fresh bamboo shoots from the mountain path, add T1 premixed powder (5.00kg of edible salt, 0.125kg of sodium D-isoascorbate, 0.02kg of L-cysteine ​​hydrochloride, 0.05kg of sodium phytate, 0.075kg of food-grade lactic acid powder, and 0.025kg of R-polysaccharide), dry curing at 25℃ for 15 days, turning the pile regularly, and directly putting the discharged material into the pool without washing it with water.

[0051] The "R-polysaccharide" is a complex of konjac glucomannan and gluconolan. Konjac glucomannan is a natural high-molecular-weight polysaccharide composed of D-mannose and D-glucose linked by β-1,4-pyranoside bonds, with a weight-average molecular weight of 200,000 to 2,000,000 Daltons; gluconolan is a linear polysaccharide composed of glucose linked by β-1,3-glycosidic bonds, with a weight-average molecular weight of 100,000 to 1,000,000 Daltons. The mass ratio of konjac glucomannan to gluconolan is 6:4. This ratio results in the most uniform and dense composite membrane structure, with the best moisture barrier properties and film-forming stability, and can be obtained directly from commercially available food-grade raw materials.

[0052] The R-polysaccharide is compounded as follows: Konjac glucomannan (weight average molecular weight 200,000-2,000,000 Daltons) and guar gum (weight average molecular weight 100,000-1,000,000 Daltons) are weighed at a mass ratio of 6:4 and added to a compounding vessel. Deionized water is added at 5-8 times the total mass of the materials. The mixture is stirred at 60-100 rpm for 20-40 minutes at 25-40℃ until both polysaccharides are completely dissolved and no visible particles or gel clumps remain. This yields an R-polysaccharide aqueous solution. This solution should be prepared and used immediately within 4 hours of preparation.

[0053] Both the konjac glucomannan and glucon can be obtained from commercially available food-grade raw materials. For example, konjac glucomannan can be obtained from food-grade konjac flour (KGM content ≥ 85%) produced by Yunnan Zhaotong Sanli Konjac Flour Co., Ltd.; glucon can be obtained from food-grade glucon (purity ≥ 95%) produced by Shandong Zhongke Biotechnology Co., Ltd. The above suppliers and product specifications are for illustrative purposes only and do not constitute a limitation on the source of raw materials. Other commercially available similar food-grade raw materials can achieve the same effect.

[0054] It should be noted that after the bamboo shoots are dry-cured, some of the salt, sodium D-isoascorbate, sodium phytate, and other components in the dry-curing powder adhering to the surface will dissolve into the preservative solution during the initial soaking stage. Measurements (sampling times: 0h, 6h, 12h, and 24h after soaking) showed that the salinity of the preservative solution increased by approximately 0.05%–0.10% within the first 24 hours, with pH fluctuations not exceeding ±0.1, after which it stabilized. This fluctuation is within the designed margin range of the preservative solution (designed salinity 4.8% ± 0.3%, designed pH 4.2–4.6), requiring no additional compensation. Therefore, the impact of directly soaking the bamboo shoots in the preservative solution without rinsing after dry curing on the stability of the preservative solution is negligible.

[0055] (2) Pretreatment of the soaking pool: Inject 1.6ppm hydrogen-rich water into the standardized soaking pool and soak for 30 minutes, then drain the pool.

[0056] The hydrogen-rich water can be prepared by any of the following methods:

[0057] Method 1 (Electrolysis): Hydrogen-rich water is prepared using a continuous electrolysis device (e.g., model FX-FQ4TD095, Yantai Fangxin Water Treatment Equipment Co., Ltd., or other commercially available devices with equivalent functions). The operating parameters are: inlet water pressure 0.05~0.15MPa, inlet water temperature 10~35℃, power supply AC 380V 50HZ. The device monitors the effluent water quality in real time using an online dissolved hydrogen detector and an online ORP meter. When the dissolved hydrogen content reaches 1.6±0.1ppm and the oxidation-reduction potential (ORP) reaches -600±20mV, the water is collected for later use.

[0058] Method 2 (Gas-Liquid Mixing Method): A gas-liquid mixing pump (e.g., model 20QY-1, Nanfang Pump Industry, or other commercially available equipment with equivalent functions) is used to mix hydrogen gas with a purity ≥99.9% with pure water in a closed circulation pipeline. The hydrogen inlet flow rate (0.5~1.0L / min) and circulation pressure (0.3~0.6MPa) are adjusted, and real-time monitoring is performed using an online dissolved hydrogen detector and an online ORP meter until the dissolved hydrogen content in the water reaches 1.6±0.1ppm and the ORP reaches -600±20mV.

[0059] Hydrogen-rich water prepared by either of the above methods should be used immediately after preparation, and the storage time should not exceed 24 hours. After 24 hours, the dissolved hydrogen content decreases to below 1.2 ppm, the ORP rises to above -400 mV, and the color protection and antioxidant effects significantly decrease, making it unsuitable for continued use in this process. If continued use is required, the water should be prepared again according to the above methods or the stored water should be retreated to meet the standards.

[0060] Hydrogen-rich water stability verification experiment:

[0061] Hydrogen-rich water (dissolved hydrogen 1.62 ppm, ORP-612 mV) was prepared according to Method 1, stored in a sealed container at room temperature, and sampled and tested every 6 hours for 48 consecutive hours. The results are shown in Table A-1.

[0062] Table A-1 Data on the Storage Stability of Hydrogen-Rich Water

[0063] Storage time (h) Dissolved hydrogen content (ppm) ORP (mV) Appearance 0 1.62 -612 Colorless and transparent 6 1.58 -598 Colorless and transparent 12 1.55 -585 Colorless and transparent 18 1.51 -562 Colorless and transparent 24 1.43 -538 Colorless and transparent 30 1.28 -485 Colorless and transparent 48 1.05 -402 Colorless and transparent

[0064] As shown in Table A-1, within 24 hours of storage, the dissolved hydrogen content is >1.4 ppm and the ORP is <-530 mV, remaining within the effective range. After 24 hours, the dissolved hydrogen content decreases to below 1.2 ppm, and the ORP rises to above -400 mV. Continued use will significantly affect the preservation effect. Therefore, the storage time of hydrogen-rich water is limited to no more than 24 hours.

[0065] (3) Preparation of preservation solution: Add the following ingredients in the following order: First, inject hydrogen-rich water base, add 4.8 parts of edible salt and stir to dissolve, add 0.22 parts of anhydrous citric acid to adjust the basic pH, add 0.08 parts of sodium phytate for chelation, add 0.05 parts of sodium D-isoascorbate, add 0.10 parts of R-polysaccharide and stir at a constant speed to form a film, add 0.07 parts of potassium cinnamate and 0.02 parts of nisin, and finally add 8 mg / kg of natamycin. Stir at a low speed of 60-80 rpm for 15 minutes until there is no precipitate.

[0066] The above order of addition is based on the solubility and synergistic effect of each component: salt is dissolved first to adjust the ionic strength; citric acid creates an acidic environment of pH 4.2~4.6 to ensure that sodium phytate (chelating agent) and sodium D-isoascorbate (reducing agent) can effectively exert their antioxidant effects; R-polysaccharide is more easily hydrated in a stable acidic system to form a protective film; potassium cinnamate, nisin, and natamycin are added after the system is stable to avoid the activity being affected by the previous stirring or high concentration of components, thus achieving the best antibacterial effect.

[0067] (4) Sealing in the pool: Spread 9.5t of dried pickled bamboo shoots evenly in the soaking pool (without squeezing or lifting), pour in the prepared preservation liquid (dried pickled bamboo shoots: preservation liquid = 1:2), with the liquid level 8-10cm above the bamboo shoot pile, and cover the pool opening with a double-layer light-proof and sealed tarpaulin (allowing a small amount of gas exchange to prevent the formation of an anaerobic environment), and store it in a light-proof and ventilated workshop at 20-32℃.

[0068] (5) Periodic maintenance: Periodic maintenance is carried out according to five time gradients: weekly, monthly, quarterly, semi-annually and year-end.

[0069] The periodic maintenance includes:

[0070] (1) Weekly maintenance: Test the salinity and pH of the preservation solution. When the liquid level drops by more than 5% of the initial liquid level (i.e., the liquid level is more than 2cm lower than the initial liquid level), replenish the sulfur-free hydrogen-rich preservation solution prepared in step (3) and visually observe the color of the bamboo shoots, the floating mold on the liquid surface, the turbidity of the water and the sour taste.

[0071] (2) Monthly maintenance: Start the circulation pump (power 0.75kW, speed 1450rpm) to circulate the water for 10 minutes. When a visible white bacterial film (i.e., "white film") appears on the liquid surface, add natamycin until the final concentration of the system reaches 10-15mg / kg (the final concentration refers to the final mass concentration of natamycin in the entire preservation solution, expressed as a mass fraction); when the pH value rises above 4.6, adjust it back to 4.2-4.6 with a 10% citric acid solution. Take samples for initial microbial screening;

[0072] (3) Quarterly maintenance: Based on the total mass of the preservative solution in the soaking tank, add 0.02% of the total mass of the preservative solution, sodium D-isoascorbate, and 0.02% of the total mass of the preservative solution, potassium cinnamate. Before adding, pre-dissolve sodium D-isoascorbate and potassium cinnamate in a small amount (about 5-10 times their respective masses) of hydrogen-rich water, then pour them evenly into the soaking tank, turn on the circulation pump (power 0.75kW, speed 1450rpm) and circulate for 5 minutes to disperse them evenly;

[0073] (4) Maintenance every six months: Submit samples for testing of total bacterial count, mold, and yeast. Adjust according to the following rules based on the test results: If the total bacterial count is >80 CFU / mL, add nisin to increase the final concentration of the preservative solution by 0.005 parts (based on 100 parts by weight of the preservative solution); if mold or yeast is detected at >10 CFU / mL, add natamycin to increase the final concentration of the preservative solution by 2-4 mg / kg. At the same time, add R-polysaccharide aqueous solution, the amount of which is 0.02%-0.05% of the total mass of the preservative solution (based on the dry matter of R-polysaccharide). Before adding, prepare the R-polysaccharide into an aqueous solution according to the above compounding method and pour it evenly into the soaking tank. Turn on the circulation pump (power 0.75kW, speed 1450rpm) and circulate for 10 minutes to repair the protective film on the surface of the bamboo shoots.

[0074] (5) Year-end maintenance: When the storage period is 12 months, open the tank and test the following items: sensory indicators (color, odor, texture), physicochemical indicators (pH value, salinity, sulfur dioxide residue), microbiological indicators (total colony count, mold, yeast), texture indicators (brittleness, expressed as shear force) and color indicators (L value, b value). The test methods are based on GB / T 10468-1989 (pH value), GB 4789.2-2022 (total colony count), GB 4789.15-2016 (mold, yeast), GB 5009.34-2022 (sulfur dioxide) and the standard methods for food texture analysis.

[0075] Test Method Description: The following test data were obtained according to national standard methods:

[0076] pH value: determined according to GB / T 10468-1989 "Determination of pH value of fruit and vegetable products";

[0077] Salinity: determined by silver nitrate titration (calculated as NaCl);

[0078] Total bacterial count: determined according to GB 4789.2-2022 "National Food Safety Standard - Microbiological Examination of Food - Determination of Total Bacterial Count";

[0079] Molds and yeasts: determined according to GB 4789.15-2016 "National Food Safety Standard - Microbiological Examination of Food: Mold and Yeast Count";

[0080] Sulfur dioxide residue: determined according to GB 5009.34-2022 "National Food Safety Standard - Determination of Sulfur Dioxide in Food".

[0081] The data in the table are from samples randomly drawn from different depths and horizontal positions in the soaking pool (one point each from the upper, middle, and lower layers, for a total of three points) at each testing time point. Each sample was tested in parallel, and the average of the three test results was taken. The testing points included 0.5m below the liquid surface, 1.2m (in the middle of the pool), and 1.8m (near the bottom of the bamboo shoot pile) to ensure that the samples represent the state of the preservative solution in the entire soaking pool.

[0082] The phased fixed-point testing data are shown in Table 1.

[0083] Table 1 Detection data from Example 1

[0084] water pH 4.32 4.38 4.41 4.35 salinity 4.78% 4.83% 4.75% 4.81% Total bacterial count in water (CFU / mL) 42 51 58 62 mold, yeast Not detected Not detected Not detected Not detected The sensory color of bamboo shoots The latter part is uniformly and naturally white, while the former part is a natural milky yellow color reminiscent of bamboo shoots. No browning or black spots No browning or black spots Commercial grade natural white and creamy yellow Odor characteristics No abnormalities No abnormalities No abnormalities No abnormalities crispness of meat crisp and tender crisp and tender Slightly softened Crisp and tender (qualified) Water state clear and bright clear and bright A small amount of extremely fine flocculent material Clear and without any film Sulfur dioxide residue in bamboo shoots (ppm) Not detected Not detected Not detected Not detected

[0085] As shown in Table 1:

[0086] (1) pH value: The pH value remained stable at 4.32 to 4.41 during the 12-month storage period, with a fluctuation range of ≤0.09. The citric acid-sodium phytate buffer system of the preservation solution maintained a stable weakly acidic environment, which was conducive to inhibiting the activity of polyphenol oxidase and the reproduction of acid-producing bacteria.

[0087] (2) Salinity: The salinity remained stable at 4.75% to 4.83% within 12 months, with a fluctuation range of ≤0.08. Under the condition of a solid-liquid ratio of 1:2, the salt content reached a dynamic balance between the bamboo shoot and the preservation liquid, and there was no need to frequently add salt.

[0088] (3) Microbiological indicators: The total bacterial count gradually increased from 42 CFU / mL in the 3rd month to 62 CFU / mL in the 12th month, and was <100 CFU / mL throughout the entire period; molds and yeasts were not detected throughout the entire period. The combined antibacterial system of potassium cinnamate, nisin and natamycin showed a sustained antibacterial effect under the synergistic effect of high salt (4.8%) and low pH (4.2-4.6).

[0089] (4) Bamboo shoot color: It remains natural within 12 months, with the back part being white and the front part being milky yellow, without browning or black spots. Hydrogen-rich water (ORP-600mV) and sodium D-isoascorbate work together to resist oxidation and effectively inhibit enzymatic browning.

[0090] (5) Crispness of the flesh: It is still "crisp and tender" after 12 months. After dry curing, the bamboo shoots are directly put into the pool without washing, which preserves the natural protective film on the surface of the bamboo shoots. The R-polysaccharide film formation further slows down the loss of moisture and the softening of fibers.

[0091] (6) Water condition: The water remains clear and free of floating film for 12 months. Periodic maintenance, such as quarterly reinforcement and semi-annual R-polysaccharide repair, effectively prevents the growth of white film on the liquid surface and the accumulation of suspended matter.

[0092] (7) Sulfur dioxide residue: Not detected within 12 months (detection limit ≤ 5 mg / kg), verifying the effectiveness of the sulfur-free process.

[0093] Example 2

[0094] This embodiment operates on the same procedure as Embodiment 1, except that the raw material is replaced with freshly harvested Yingde bamboo shoots. The dry-curing process is combined with T2 premixed powder (based on 25kg of fresh bamboo shoots: 5.00kg of edible salt, 0.125kg of D-isoascorbic acid sodium salt, 0.0125kg of L-cysteine ​​hydrochloride, 0.03kg of phytate sodium salt, 0.04kg of anhydrous citric acid, and 0.025kg of R-polysaccharide). The remaining soaking tank, preservation solution, and maintenance process are completely identical.

[0095] The phased fixed-point testing data are shown in Table 2.

[0096] Table 2 Detection data from Example 2

[0097] water pH 4.30 4.36 4.42 4.37 salinity 4.82% 4.77% 4.84% 4.79% Total bacterial count in water (CFU / mL) 38 46 53 59 mold, yeast Not detected Not detected Not detected Not detected The sensory color of bamboo shoots uniform off-white No browning or black spots No browning or black spots uniform off-white Odor characteristics No abnormalities No abnormalities No abnormalities No abnormalities crispness of meat crisp and tender crisp and tender crisp and tender Crisp and tender (qualified) Water state clear and bright clear and bright clear and bright Clear and free of mold Sulfur dioxide residue in bamboo shoots (ppm) Not detected Not detected Not detected Not detected

[0098] As shown in Table 2:

[0099] Example 2 used Yingde bamboo shoots as raw material and T2 dry-curing formula (medium whiteness type). The trend of various indicators was basically the same as that of Example 1: pH value was stable at 4.30-4.42, salinity was stable at 4.77%-4.84%, total bacterial count was ≤59 CFU / mL, and mold, yeast and sulfur dioxide residues were not detected.

[0100] The main difference from Example 1 lies in the color of the bamboo shoots: the T2 formula has a lower whiteness than T1 due to the halved amount of L-cysteine ​​hydrochloride and the absence of lactic acid powder, presenting a "uniform off-white color", which matches the medium whiteness requirement for the bulk deep processing of Yingde bamboo shoots.

[0101] The above results show that the process of the present invention has good adaptability to different varieties of bamboo shoots. By changing the dry curing formula, the whiteness of the bamboo shoots can be adjusted as needed without affecting the stability of the preservation liquid system and the 12-month preservation effect.

[0102] Example 3

[0103] This embodiment operates on the same procedure as Embodiment 1, except that the raw material is replaced with freshly harvested Yingde bamboo shoots. The dry-curing process is combined with T3 premixed powder (based on 25kg of fresh bamboo shoots: 5.00kg of edible salt, 0.075kg of D-isoascorbic acid sodium salt, 0.03kg of phytate sodium salt, 0.075kg of tea polyphenols, 0.03kg of anhydrous citric acid, and 0.025kg of R-polysaccharide). The rest of the soaking tank, preservation solution, and maintenance process are completely the same.

[0104] The phased fixed-point testing data are shown in Table 3.

[0105] Table 3 Detection data from Example 3

[0106] water pH 4.34 4.40 4.43 4.39 salinity 4.76% 4.85% 4.74% 4.82% Total bacterial count in water (CFU / mL) 45 54 61 68 mold, yeast Not detected Not detected Not detected Not detected The sensory color of bamboo shoots uniform off-white No browning or black spots No browning or black spots uniform beige Odor characteristics No abnormalities No abnormalities No abnormalities No abnormalities crispness of meat crisp and tender crisp and tender Light Microsoft Meets the requirements for seasoned bamboo shoot processing Water state clear and bright A small amount of fine flocculent material No white film Clear and stable Sulfur dioxide residue in bamboo shoots (ppm) Not detected Not detected Not detected Not detected

[0107] As shown in Table 3:

[0108] Example 3 uses Yingde bamboo shoots as raw material and T3 dry-curing formula (low whiteness type, with added tea polyphenols to replace L-cysteine ​​hydrochloride). The core indicators (pH, salinity, total bacterial count, mold / yeast, sulfur dioxide residue) are consistent with those of Examples 1 and 2, and all meet the storage quality requirements after 12 months.

[0109] In terms of color, after 12 months, it is "uniform beige," with a whiteness lower than that of Examples 1 and 2, which is consistent with the design goal of the T3 formula—the sauces and spices in the deep processing of seasoned bamboo shoots will cover the color of the bamboo shoots, so there is no need for excessive whiteness. In terms of crispness, after 12 months, it is "meets the requirements for processing seasoned bamboo shoots," which is slightly lower than that of Examples 1 and 2, but fully meets the requirements for the crispness of raw materials in the deep processing of seasoned bamboo shoots (such as red oil bamboo shoot strips and pickled pepper bamboo shoot slices).

[0110] The above results indicate that the T3 formula provides a more cost-effective technical solution for the deep processing of seasoned bamboo shoots by reducing the whiteness requirement in exchange for more economical raw material costs.

[0111] Comparison experiment of feeding sequence:

[0112] To verify the necessity of a specific order of ingredient addition, a comparative experiment was conducted as follows. The preservation solution formula from Example 1 (100 parts hydrogen-rich water, 4.8 parts edible salt, 0.22 parts anhydrous citric acid, 0.08 parts sodium phytate, 0.05 parts sodium D-isoascorbate, 0.10 parts R-polysaccharide, 0.07 parts potassium cinnamate, 0.02 parts nisin, 8 mg / kg natamycin) was used, added in three different orders, with all other conditions consistent with Example 1. The results were observed after 12 months of storage.

[0113] experimental group Feeding sequence Appearance Film uniformity 12-month-old bamboo shoot color Standard order ① Salt → ② Citric acid → ③ Sodium phytate → ④ Sodium isoascorbate → ⑤ R-polysaccharide → ⑥ Potassium cinnamate + Nisin → ⑦ Natamycin Clear and uniform The membrane is continuous and uniform. Natural white / milky yellow Sequence A First add preservatives (⑥+⑦), then add citric acid (②). Slightly cloudy The film is uneven in thickness and has a grainy texture. Mild yellow spots Sequence B R-polysaccharide (⑤) and citric acid (②) are swapped The solution is viscous and contains undissolved colloids. The membrane is discontinuous and has cracks. Obvious browning at the edges

[0114] As shown in the table above, changing the order of ingredient addition significantly reduced the solubility and film-forming uniformity of R-polysaccharide, leading to a deterioration in the preservation effect. This demonstrates that the ingredient addition order described in this invention has a synergistic effect on obtaining a stable preservation solution and an ideal preservation effect.

[0115] Comparative Example 1

[0116] The preservation solution contains only pure water and 0.2% food-grade sodium metabisulfite, without using hydrogen-rich water or quarterly replenishment and maintenance. The remaining dry curing (using T1) and soaking tank loading parameters are completely consistent with those in Example 1.

[0117] The phased testing data are shown in Table 4.

[0118] Table 4 Detection data of Comparative Example 1

[0119] Testing items Store for 3 months Store for 6 months Store for 9 months Store for 12 months water pH 4.46 4.61 4.77 5.02 Total bacterial count in water (CFU / mL) 2 5 5 4 mold, yeast Not detected Not detected Not detected Not detected bamboo shoot color unnatural pale No browning or black spots No browning or black spots unnatural pale Odor characteristics Strong, pungent smell of sulfur dioxide The pungent smell of sulfur was strong when the lid was opened. Sulfur odor continued to emanate from the workshop. Strong and pungent when the lid is opened crispness of meat crisp and tender crisp and tender crisp and tender Crisp and tender (qualified) Water state clear and bright clear and bright clear and bright A small amount of fine flocculent material Sulfur dioxide residue in bamboo shoots (ppm) 1530 1448 1486 1710

[0120] As shown in Table 4:

[0121] Comparative Example 1 used conventional sodium metabisulfite (0.2%) for color protection and antibacterial properties, without using hydrogen-rich water or performing quarterly reinforcement maintenance, and exhibited the following characteristics:

[0122] (1) Stable antibacterial effect: Total bacterial count ≤ 5 CFU / mL, no molds and yeasts detected, and the bactericidal effect is better than that of the present invention, but this comes at the cost of the strong bactericidal effect of chemical additives.

[0123] (2) Distortion of bamboo shoot color: Within 12 months, the bamboo shoots appear "unnaturally pale," which contrasts with the "natural white / milky yellow / off-white" color of the embodiments of the present invention. The strong reducing bleaching effect of sodium metabisulfite destroys the natural pigments of the bamboo shoots.

[0124] (3) Continuous release of pungent sulfur odor: The sulfur odor is pungent after opening and worsens with storage. Downstream processing requires the addition of multiple desulfurization and rinsing processes, which significantly increases water, labor and energy costs.

[0125] (4) Sulfur dioxide residue seriously exceeded the standard: 1530 ppm after 3 months and 1710 ppm after 12 months, which is more than 30 times higher than the limit of 50 mg / kg for exported food in GB 2760. The data for 12 months is higher than that for 3 months. The reason for this may be that the relative concentration of sulfur dioxide in the bamboo shoots increases with the extension of storage time, moisture evaporation and continuous absorption of sulfites by the bamboo shoots.

[0126] (5) pH continued to rise: from 4.46 in the 3rd month to 5.02 in the 12th month, exceeding the control range of this invention (4.2-4.6). The sodium metabisulfite system lacks pH buffer design and periodic adjustment maintenance.

[0127] In summary, although sodium metabisulfite is superior to the present invention in terms of antibacterial effect, it has insurmountable defects in terms of natural color, odor safety, residue compliance, and environmental and economic efficiency.

[0128] Comparative Example 2

[0129] Hydrogen-rich water was omitted, and ordinary pure water was used to prepare the preservation solution. Quarterly reinforcement maintenance was not performed. Freshly harvested Yingde bamboo shoots were used as raw materials, and T2 formula powder was used for dry curing. The remaining operation steps were exactly the same as in Example 1.

[0130] The phased testing data are shown in Table 5.

[0131] Table 5 Detection data of Comparative Example 2

[0132] Testing items Store for 3 months Store for 6 months Store for 9 months Store for 12 months water pH 4.41 4.56 3.86 3.77 Total bacterial count in water (CFU / mL) 92 1.8×10² <![CDATA[2.1×10 4 ]]> <![CDATA[4.6×10 5 ]]> mold, yeast Not detected Not detected Floating mold on liquid surface Floating mold on liquid surface bamboo shoot color Slightly yellowish edges Localized yellow spots Large areas of blackening and browning Overall severe browning Odor characteristics No abnormalities Slightly fermented sour taste Noticeably rancid Strong sour and rotten smell crispness of meat crisp and tender Partially softened Partially soft and rotten There are many soft and mushy ones Water state clear and bright A small amount of fine flocculent material Mold on the water surface, the water is relatively turbid. Mold on the water surface, turbid water Sulfur dioxide residue in bamboo shoots (ppm) Not detected Not detected Not detected Not detected

[0133] As shown in Table 5:

[0134] Comparative Example 2 eliminated hydrogen-rich water and used ordinary pure water to prepare the preservative solution, and did not implement quarterly reinforcement maintenance, exhibiting a typical "mid-to-late stage failure" pattern:

[0135] (1) Month 3: pH 4.41, total bacterial count 92 CFU / mL (close to the limit of 100 CFU / mL), slightly yellowish color at the edges, no abnormal odor. Ordinary pure water system has a certain preservation ability in the short term.

[0136] (2) Month 6: pH rises to 4.56, total bacterial count increases to 1.8×10² CFU / mL, local yellow spots appear on bamboo shoots, fine flocs appear in the water, and there is a slight fermented sour taste. Without hydrogen-rich water, there is a lack of continuous reducing capacity. After the reducing components such as sodium D-isoascorbate are depleted, they cannot be regenerated, and the antioxidant system fails.

[0137] (3) In the 9th month: the pH dropped to 3.86 (rancidity) and the total number of colonies surged to 2.1×10 4 CFU / mL, surface mold, large areas of blackening and browning of bamboo shoots, obvious rancid smell, and partial softening and rotting. Without quarterly reinforcement and maintenance, the antibacterial components are depleted and cannot be replenished, leading to the proliferation of microorganisms and acid production.

[0138] (4) 12th month: pH 3.77, total bacterial count 4.6×10 5 The concentration of CFU / mL was high, with severe surface mold, heavy browning of the bamboo shoots, a strong sour and rotten smell, and a significant amount of soft and mushy flesh. A preservation system without hydrogen-rich water and periodic maintenance can only maintain an effective shelf life of approximately 3 months.

[0139] Comparing Comparative Example 2 with Example 2, it can be seen that: hydrogen-rich water (dissolved hydrogen 1.6 ppm, ORP-600 mV) continuously provides a reducing environment, significantly slowing down the consumption rate of reducing components; periodic maintenance continuously replenishes the consumed antibacterial and antioxidant components in the middle and later stages. The synergistic effect of both achieves a long-lasting preservation of 12 months.

[0140] Results Analysis

[0141] As shown in Examples 1-3, under the condition of 12 months of sealed storage at room temperature, the pH of the water remains stable within the standard range of 4.2-4.6 throughout the process, with minimal salinity fluctuations. The total bacterial count is consistently controlled below 100 CFU / mL, and molds and yeasts are not detected at all. Sulfur dioxide residues are also undetectable (detection limit ≤5 mg / kg). The three types of dry-curing powders can be used to adjust the whiteness of the bamboo shoots as needed (T1: L value 85-90, natural white / milky yellow; T2: L value 78-85, uniform off-white; T3: L* value 70-78, uniform off-white). The bamboo shoots have a natural color, no irritating odor, require no desulfurization process, and their crispness meets the standards for commercial or seasoned bamboo shoot processing.

[0142] As shown in Comparative Example 1, although sodium metabisulfite is stable in protecting color and inhibiting bacteria, and there is no large-scale blackening or mold growth throughout the process, it has significant drawbacks. Sulfur dioxide residue in bamboo shoots accumulates continuously during storage, reaching as high as 1710 ppm after 12 months, far exceeding the export limit of 50 mg / kg. The bamboo shoots turn a pale white and continuously release a pungent sulfur smell. Each batch of processing requires multiple stages of desulfurization and rinsing, which greatly increases water, labor, and energy costs, making it unsuitable for clean labels and pre-prepared vegetable orders for foreign trade.

[0143] As shown in Comparative Example 2, after the removal of hydrogen-rich water and the failure to implement quarterly reinforcement and maintenance, the pH and total bacterial count gradually exceeded the standards after 3 months. After 9 months, the bamboo shoots turned black in large areas, mold grew in the water, and the bamboo shoots became sour and soft. It can only achieve short-term preservation within 3 months and cannot meet the long-term storage requirements of 12 months.

[0144] The mechanism by which this invention achieves its technical effects can be summarized as follows: the continuous reducing effect of hydrogen-rich water (ORP-600mV) provides a long-lasting antioxidant environment for the entire preservation system, significantly slowing down the consumption rate of reducing components such as sodium D-isoascorbate; the film-forming protection of R-polysaccharides forms a physical barrier on the surface of the bamboo shoots, reducing moisture loss and oxygen contact; and the periodic dynamic replenishment of the antibacterial (nisin, natamycin, potassium cinnamate) and antioxidant (sodium D-isoascorbate) components, which are continuously replenished in the middle and later stages, repairs the R-polysaccharide protective film. These three factors work synergistically to enable the sulfur-free preservation system to overcome the technical bottleneck of 6 months under normal temperature conditions and stably achieve a long-lasting preservation of 12 months.

[0145] In summary, the three types of premixed powders, T1, T2, and T3, are respectively suitable for high-end clear-water bamboo shoots, bulk bamboo shoots, and seasoned bamboo shoots, and all meet the standards for the two mainstream raw materials, high-mountain small-diameter bamboo shoots and Yingde bamboo shoots. The process of this invention fully covers the entire industrial process of powder dry curing, hydrogen-rich soaking, standardized soaking tanks, and periodic maintenance. It has strong versatility, and the parameters can be directly implemented for mass production.

[0146] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots, characterized in that, Includes the following steps: (1) Dry curing process: Freshly harvested bamboo shoots are mixed with dry curing powder and dry curing is carried out at 20-32℃ for 15 days. After dry curing, the bamboo shoot raw materials are not washed or soaked in water, but directly sent to the soaking pool for preservation. The dry curing powder contains at least edible salt, sodium D-isoascorbate, sodium phytate and R-polysaccharide. (2) Pretreatment of the soaking pool: Inject hydrogen-rich water with 1.6 ppm of dissolved hydrogen into the standardized soaking pool and soak for 30 minutes, then drain and clean for later use. (3) Preparation of preservation solution: Using hydrogen-rich water with 1.6 ppm hydrogen and ORP-600 mV as the base, add the following components in the following order: ① Dissolve edible salt by stirring, ② Adjust pH with anhydrous citric acid, ③ Sodium phytate, ④ Sodium D-isoascorbate, ⑤ R-polysaccharide by stirring at a constant speed to form a film, ⑥ Potassium cinnamate and nisin, ⑦ Natamycin; after adding all the components, stir at a low speed for 15 min until there is no precipitate to obtain sulfur-free hydrogen-rich preservation solution; The sulfur-free hydrogen-rich preservative solution is composed of the following components in parts by weight: 100 parts hydrogen-rich water, 4.8 parts edible salt, 0.22 parts anhydrous citric acid, 0.08 parts sodium phytate, 0.05 parts sodium D-isoascorbate, 0.10 parts R-polysaccharide, 0.07 parts potassium cinnamate, 0.02 parts nisin, and 8 mg / kg natamycin. (4) Sealing in the pool: Spread the dried pickled bamboo shoots evenly in the soaking pool, and pour in the sulfur-free hydrogen-rich preservation liquid prepared in step (3). The mass ratio of dried pickled bamboo shoots to sulfur-free hydrogen-rich preservation liquid is 1:

2. The sulfur-free hydrogen-rich preservation liquid completely submerges the material, and the liquid level is 8-10cm above the bamboo shoot pile. Cover the pool opening with a double-layer light-proof and sealed tarpaulin, and store it in a light-proof and ventilated workshop at 20-32℃. (5) Periodic maintenance: Periodic maintenance is carried out according to five time gradients: weekly, monthly, quarterly, semi-annually and year-end.

2. The sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots according to claim 1, characterized in that, The dry-curing powder is dry-curing formula T1, used for high-whiteness high-mountain small-diameter bamboo shoots. Its formula is as follows: based on 25kg of fresh bamboo shoots, 5.00kg of edible salt, 0.125kg of D-isoascorbic acid sodium salt, 0.02kg of L-cysteine ​​hydrochloride, 0.05kg of sodium phytate, 0.075kg of food-grade lactic acid powder, and 0.025kg of R-polysaccharide.

3. The sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots according to claim 1, characterized in that, The dry-curing powder is dry-curing formula T2, used for the large-scale deep processing of Yingde bamboo shoots with medium whiteness requirements. Its formula is as follows: based on 25kg of fresh bamboo shoots, 5.00kg of edible salt, 0.125kg of sodium D-isoascorbate, 0.0125kg of L-cysteine ​​hydrochloride, 0.03kg of sodium phytate, 0.04kg of anhydrous citric acid, and 0.025kg of R-polysaccharide.

4. The sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots according to claim 1, characterized in that, The dry-curing powder is dry-curing formula T3, used for the deep processing of Yingde bamboo shoots with low whiteness requirements. Its formula is as follows: based on 25kg of fresh bamboo shoots, 5.00kg of edible salt, 0.075kg of sodium D-isoascorbate, 0.03kg of sodium phytate, 0.075kg of tea polyphenols, 0.03kg of anhydrous citric acid, and 0.025kg of R-polysaccharide.

5. The sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots according to claim 1, characterized in that, The standardized hot spring pool has individual dimensions of 3m long × 2.8m wide × 2.5m deep, with a total volume of 21m³. 3 The effective liquid filling depth is 2.2m, with a 0.3m reserved sealing safety space, and the effective preservation liquid volume per tank is 18.48m³. 3 The maximum capacity of a single pool is 9.5 tons of dried pickled bamboo shoots.

6. The sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots according to claim 1, characterized in that, The periodic maintenance includes: (1) Weekly maintenance: Test the salinity and pH of the preservation solution. When the solution is insufficient, replenish the sulfur-free hydrogen-rich preservation solution prepared in step (3). Visually observe the color of the bamboo shoots, the surface mold, the turbidity of the water and the sour taste. (2) Monthly maintenance: Start the circulating pump to circulate the water for 10 minutes. When a white film appears, add natamycin. When the pH rises, use citric acid to adjust it back to 4.2-4.6 and take samples for initial microbial screening. (3) Quarterly maintenance: Add 0.02% sodium D-isoascorbate and 0.02% potassium cinnamate by weight of the total preservative solution; (4) Maintenance every six months: submit samples for total bacterial count, mold and yeast tests, adjust the dosage of nisin and natamycin based on the test data, and supplement with R-polysaccharide; (5) Year-end maintenance: When the storage period is 12 months, open the tank to test sensory indicators, physicochemical indicators, microbiological indicators, texture indicators and color indicators.

7. The sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots according to claim 1, characterized in that, The sulfur-free hydrogen-rich preservative solution does not contain sodium metabisulfite or sodium bisulfite.

8. The sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots according to claim 1, characterized in that, The bamboo shoots mentioned are either high-altitude small-path bamboo shoots or Yingde Ma bamboo shoots.

9. A sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots according to claim 1, characterized in that, The dried pickled bamboo shoots described in step (4) are spread evenly without being squeezed or suspended.

10. A sulfur-free, hydrogen-rich, long-lasting preservation process for bamboo shoots according to any one of claims 1 to 9, characterized in that, The process achieves 12-month long-term preservation of bamboo shoots at room temperature (20-32℃), with no detectable sulfur dioxide residue in the bamboo shoots, total bacterial count in the water controlled below 100 CFU / mL throughout the process, and no detectable molds or yeasts.