A processing and fresh-keeping method of fresh bamboo shoots without adding fresh bamboo shoots and bamboo shoots obtained by the method

Abstract

This invention relates to the field of agricultural product deep processing technology, specifically to a method for processing and preserving fresh bamboo shoots without additives, and the bamboo shoots obtained from this method. The method employs a two-stage boiling process: a first gentle boil to inactivate enzymes and protect color; a second boil for deep sterilization; combined with a cooling and soaking process after the first boil, effectively removing astringency, locking in freshness, and maintaining crispness; subsequently, vacuum packaging while still hot maximizes the isolation from oxygen and microbial contamination, supplemented by refrigeration preservation technology. This allows for the maintenance of excellent taste and appearance quality of fresh bamboo shoots without any additives throughout the entire process, significantly extending their shelf life.

Description

Technical Field

[0001] This invention belongs to the field of agricultural product deep processing technology, specifically involving a method for processing and long-term preservation of fresh bamboo shoots without any additives, using purely physical processes, and the bamboo shoots obtained by this method. Background Technology

[0002] Currently, the main technical challenges in bamboo shoot preservation are as follows: 1. Fresh bamboo shoots are highly susceptible to enzymatic browning, lignification, and deterioration in taste after harvesting, resulting in a very short shelf life at room temperature; 2. Conventional fresh bamboo shoot preservation processes on the market generally add chemical additives such as preservatives, color protectants, and bleaching agents, which do not meet the consumer demand for green, healthy, and additive-free foods; 3. Traditional additive-free boiling preservation processes typically only preserve freshness for a few days to several tens of days, which cannot meet the needs of long-term storage, long-distance transportation, and large-scale sales; 4. Simple boiling and ordinary cooling processes easily cause fresh bamboo shoots to become soft and mushy, with a strong astringent taste and loss of flavor, resulting in unstable product quality.

[0003] Although Chinese patent CN1742620A discloses a method for processing and preserving cooked bamboo shoots, including the following steps: within 12 hours of harvesting fresh bamboo shoots, peel and cut them into pieces, then steam them in a boiler until they are fully cooked, remove them, cool them with cold water, and then air-dry them for 1-2 hours to dry the surface water. After that, package and seal the whole bamboo shoots, then sterilize them with ultraviolet light, and finally refrigerate them in a freezing device below 0°C and above -10°C. Although the preservation time can be up to 7 months, the method requires high-temperature sterilization and enzyme inactivation, followed by ultraviolet sterilization, and finally freezing and low-temperature preservation. The process is complicated, the storage cost is high, and freezing has a great impact on the taste of bamboo shoots.

[0004] Chinese patent text CN108323566A A method for preserving and processing square bamboo shoots is disclosed, including material selection and preparation, boiling for blanching, peeling and removing skin, secondary steaming, sorting and grading, gradually increasing the intensity of kneading in several stages followed by gradually increasing the temperature for hot air drying, soaking, vacuum packaging, and gradient freezing to -2±1℃. Specifically, the first boiling for blanching requires pre-boiling in hot water at 100-120℃ for 5-10 minutes; the second steaming involves boiling in hot water at 80-90℃ for 40-60 minutes; the gradually increasing intensity of kneading followed by gradually increasing the temperature for hot air drying is as follows: the first kneading is light for 5-10 minutes, followed by drying with hot air at 90-100℃ for 5-10 minutes; the second kneading is more intense than the first, for 5-10 minutes, followed by drying with hot air at 100-120℃ for 5-10 minutes; the third kneading is more intense than the second, for 5-10 minutes, followed by drying with hot air at 120-140℃. This method involves a complex process, requiring the addition of a soaking solution made from bamboo shoot leaves, garlic, ginger, pomelo peel, tea leaves, perilla leaves, and white wine during the preparation stage to sterilize and preserve the bamboo shoots. Moreover, the complex composition of the soaking solution severely affects the original flavor of the bamboo shoots.

[0005] Therefore, existing methods for preserving bamboo shoots still need to be improved. Summary of the Invention

[0006] To address the problems of existing technologies that rely on additives, have short shelf lives, and produce poor product quality, this invention provides a method for processing and preserving fresh bamboo shoots. This method employs a purely physical process that can significantly improve the crispness and tenderness of fresh bamboo shoots without any additives, effectively extend the product's shelf life, and achieve good color retention. The method is simple, environmentally friendly, and suitable for large-scale industrial production.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for processing and preserving fresh bamboo shoots without additives, comprising the following steps:

[0009] Raw material processing and cutting;

[0010] First boiling: Submerge the chopped fresh bamboo shoots in clean water, heat to a boil, and then simmer for 10-15 minutes.

[0011] Cleaning and soaking: After the first boil, remove the fresh bamboo shoots, rinse them with clean water and let them cool, then soak them.

[0012] Second boiling: Take out the soaked fresh bamboo shoots and put them back into fresh water and bring to a boil over high heat for 10-15 minutes.

[0013] Vacuum packaging: After the second boiling, immediately vacuum seal the package while it is still hot;

[0014] Cooling with clean water: Place the vacuum-packed fresh bamboo shoots in clean water to cool to room temperature;

[0015] Refrigeration and preservation: Store the cooled fresh bamboo shoots in the refrigerator.

[0016] Through a two-stage boiling process, the first gentle boil inactivates enzymes and preserves color, while the second boil deeply sterilizes the bamboo shoots. Combined with cooling and soaking after the first boil, the astringency is removed, freshness is locked in, and crispness is maintained. Vacuum packaging while still hot maximizes the isolation from oxygen and microorganisms, and refrigeration preserves freshness, thus maximizing the shelf life. This process ensures the taste and appearance without any additives, while also maximizing the shelf life of fresh bamboo shoots.

[0017] Preferably, in the "raw material processing and cutting" step, fresh, tender bamboo shoots that are free from rot, insect infestation, and mechanical damage are selected, and after washing, peeling, and trimming, they are cut into segments, slices, or strips.

[0018] Preferably, in the "washing and soaking" step, the food is first rinsed and cooled in flowing water, and then soaked in water. The rapid cooling by the flowing water avoids the residual heat from simmering and softening the food, while removing astringency and impurities. This quickly locks in freshness, removes astringency, and preserves crispness, significantly improving the taste and appearance.

[0019] More preferably, in the "cleaning and soaking" step, the water is circulated and cooled for 10-30 minutes.

[0020] More preferably, in the "washing and soaking" step, after washing and cooling, the sample is soaked in clean water for 60-120 minutes.

[0021] More preferably, in the "washing and soaking" step, the water is changed at least once during the soaking process.

[0022] Preferably, in the "water cooling" step, the vacuum-packed fresh bamboo shoots are soaked in room temperature water and cooled to room temperature.

[0023] Preferably, in the "refrigeration and preservation" step, the cooled fresh bamboo shoots are refrigerated and stored at 2-10°C. Under the condition of no additives, the shelf life can be up to 1 year, while maintaining the white color, crisp and tender texture, and pure flavor.

[0024] In some preferred embodiments, a reheating and cooling step is included between the "water cooling" and "refrigeration preservation" steps to better sterilize and extend the shelf life.

[0025] In another aspect, the present invention also provides bamboo shoots prepared by the above-described method for processing and preserving fresh bamboo shoots.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The fresh bamboo shoot processing and preservation method of this invention is simple, requires low equipment investment, and is standardized in operation, making it suitable for large-scale production in small and medium-sized agricultural product processing plants. It boasts a high yield, stable quality, and significant economic benefits. The resulting fresh bamboo shoots are white in color, do not turn brown, have a crisp and tender texture, and are free of astringency, preserving the original flavor of the bamboo shoots to the greatest extent possible. Furthermore, the shelf life can be up to one year, facilitating storage, transportation, wholesale, and nationwide sales. The product is additive-free, green, and healthy, meeting the demands of the high-end market and ensuring safe and worry-free consumption. Attached Figure Description

[0028] Figure 1 Images of bamboo shoot products obtained in Examples 1-3 of this invention. Detailed Implementation

[0029] The present invention is further illustrated by the following embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the present invention.

[0030] This invention provides a method for processing and preserving fresh bamboo shoots that is additive-free, has a crisp and tender texture, and a long shelf life. It achieves color protection, crispness retention, sterilization, and long-term preservation of fresh bamboo shoots through a purely physical process, solving the problems of existing technologies that rely on additives, have short shelf life, and poor quality. This method is suitable for industrial production.

[0031] The fresh bamboo shoot processing and preservation method of the present invention includes the following steps in sequence:

[0032] Raw material processing and cutting: In this step, fresh, tender bamboo shoots that are free from rot, insect infestation, and mechanical damage are usually selected. After washing, peeling, trimming to remove old roots and coarse fibers, they are cut into sections, slices, or strips for later use.

[0033] First boiling: Immerse the chopped fresh bamboo shoots in clean water, heat to a boil, and then simmer for 10-15 minutes. The high temperature deactivates the polyphenol oxidase in the bamboo shoots, preventing browning and aging, and also completes the initial sterilization. In some embodiments, the first boiling process is carried out at a simmer for 10, 12, 14, or 15 minutes, etc.

[0034] Washing and Soaking: After the first boiling, the fresh bamboo shoots are removed, rinsed with clean water and cooled, then soaked. Washing and cooling quickly lowers the temperature and preserves crispness, while soaking further removes astringency and impurities. In some preferred embodiments, the bamboo shoots can be quickly cooled with running water first to prevent residual heat from simmering and softening them, thus ensuring good texture; then soaking removes astringency. Further, in some preferred embodiments, the rapid cooling time with running circulating water is 10-30 minutes, followed by soaking in clean water for 60-120 minutes. In some embodiments, the rapid cooling time with running circulating water is 10 minutes, 20 minutes, 25 minutes, or 30 minutes, etc. In some embodiments, the soaking time in clean water is 60 minutes, 80 minutes, 100 minutes, or 120 minutes, etc.

[0035] Second boiling: Remove the soaked bamboo shoots and put them back into fresh water. Bring to a boil over high heat for 10-15 minutes. ， The second boiling process further inactivates microorganisms and residual enzymes, deeply sterilizing the bamboo shoots while stabilizing their tissue structure and maintaining their crisp and tender texture. In some embodiments, the second boiling process involves boiling over high heat for 10 minutes, 12 minutes, or 15 minutes.

[0036] Vacuum packaging: After the second boiling, the fresh bamboo shoots are immediately vacuum-sealed while still hot; the high temperature removes air from the bag, creating a sealed, sterile environment and preventing secondary contamination.

[0037] Cooling with clean water: Place the vacuum-packed fresh bamboo shoots in clean water to cool to room temperature to avoid high temperature and pressure affecting the taste and packaging stability.

[0038] Refrigeration preservation: Store the cooled fresh bamboo shoots in the refrigerator for preservation. In some preferred embodiments, refrigeration at 2~10℃ yields better results. More preferably, they can be stored at room temperature in a well-ventilated and cool place for up to six months.

[0039] This invention employs a two-stage boiling process: a first gentle boil to inactivate enzymes and preserve color; and a second boil for deep sterilization. Combined with a cooling and soaking process after the first boil, it effectively removes astringency, locks in freshness, and maintains crispness. Subsequent hot vacuum packaging maximizes the isolation from oxygen and microbial contamination, and refrigeration preservation technology further enhances the preservation. This allows for the maintenance of excellent taste and appearance quality of fresh bamboo shoots without any additives, significantly extending their shelf life. Especially under refrigeration conditions of 2–8℃, the shelf life of additive-free fresh bamboo shoots can reach one year, exceeding the industry's conventional shelf-life limits.

[0040] Example 1

[0041] A method for processing and preserving fresh bamboo shoots without additives includes the following steps:

[0042] 1) Raw material processing and cutting: Select fresh, tender bamboo shoots that are free from rot, insects, and mechanical damage. After washing, peeling, trimming and removing old roots and coarse fibers, cut them into slices for later use.

[0043] 2) First boiling: Immerse the cut fresh bamboo shoots in clean water, heat to boiling, and then keep simmering for about 10 minutes.

[0044] 3) Cleaning and soaking: Quickly remove the fresh bamboo shoots after the first boil and put them into continuously flowing, circulating clean water for 20 minutes to quickly clean and cool them. Then soak them in clean water for 80 minutes, changing the water once in between.

[0045] 4) Second boiling: Take out the cooled and soaked fresh bamboo shoots and put them back into clean water and bring to a boil over high heat for 10 minutes.

[0046] 5) Vacuum packaging: After the second boiling, immediately pack the fresh bamboo shoots into aseptic food packaging bags while they are still hot and vacuum seal them.

[0047] 6) Cooling with water: Soak the vacuum-packed fresh bamboo shoots in room temperature water until they cool to room temperature.

[0048] 7) Refrigeration and preservation: Store the cooled fresh bamboo shoots at 2~8℃ for preservation.

[0049] Example 2

[0050] A method for processing and preserving fresh bamboo shoots without additives includes the following steps:

[0051] 1) Raw material processing and cutting: Select fresh, tender bamboo shoots that are free from rot, insects, and mechanical damage. After washing, peeling, trimming and removing old roots and coarse fibers, cut them into slices for later use.

[0052] 2) First boiling: Immerse the cut fresh bamboo shoots in clean water, heat to boiling, and then keep simmering for about 10 minutes.

[0053] 3) Cleaning and soaking: Quickly remove the fresh bamboo shoots after the first boil and put them into continuously flowing, circulating clean water for 25 minutes to quickly clean and cool them. Then soak them in clean water for 100 minutes, changing the water once in between.

[0054] 4) Second boiling: Take out the cooled and soaked fresh bamboo shoots and put them back into clean water and bring to a boil over high heat for 12 minutes.

[0055] 5) Vacuum packaging: After the second boiling, immediately pack the fresh bamboo shoots into aseptic food packaging bags while they are still hot and vacuum seal them.

[0056] 6) Cooling with water: Soak the vacuum-packed fresh bamboo shoots in room temperature water until they cool to room temperature.

[0057] 7) Refrigeration and preservation: Store the cooled fresh bamboo shoots at 2~8℃ for preservation.

[0058] Example 3

[0059] A method for processing and preserving fresh bamboo shoots without additives includes the following steps:

[0060] 1) Raw material processing and cutting: Select fresh, tender bamboo shoots that are free from rot, insects, and mechanical damage. After washing, peeling, trimming and removing old roots and coarse fibers, cut them into slices for later use.

[0061] 2) First boiling: Immerse the cut fresh bamboo shoots in clean water, heat to boiling, and then keep simmering for about 15 minutes.

[0062] 3) Cleaning and soaking: Quickly remove the fresh bamboo shoots after the first boil and put them into continuously flowing, circulating clean water for a quick rinse and cooling for 30 minutes. Then soak them in clean water for 120 minutes, changing the water once in between.

[0063] 4) Second boiling: Take out the cooled and soaked fresh bamboo shoots and put them back into clean water and bring to a boil over high heat for 15 minutes.

[0064] 5) Vacuum packaging: After the second boiling, immediately pack the fresh bamboo shoots into aseptic food packaging bags while they are still hot and vacuum seal them.

[0065] 6) Cooling with water: Soak the vacuum-packed fresh bamboo shoots in room temperature water until they cool to room temperature.

[0066] 7) Refrigeration and preservation: Store the cooled fresh bamboo shoots at 2~8℃ for preservation.

[0067] Comparative Example 1

[0068] A method for processing and preserving fresh bamboo shoots without additives includes the following steps:

[0069] 1) Raw material processing and cutting: Select fresh, tender bamboo shoots that are free from rot, insects, and mechanical damage. After washing, peeling, trimming and removing old roots and coarse fibers, cut them into slices for later use.

[0070] 2) First boiling: Immerse the cut fresh bamboo shoots in clean water, heat to boiling, and then keep simmering for about 20 minutes.

[0071] 3) Cleaning and soaking: Quickly remove the fresh bamboo shoots after the first boil and put them into continuously flowing, circulating clean water for a quick rinse and cooling for 30 minutes. Then soak them in clean water for 120 minutes, changing the water once in between.

[0072] 4) Second boiling: Take out the cooled and soaked fresh bamboo shoots and put them back into clean water and bring to a boil over high heat for 15 minutes.

[0073] 5) Vacuum packaging: After the second boiling, immediately pack the fresh bamboo shoots into aseptic food packaging bags while they are still hot and vacuum seal them.

[0074] 6) Cooling with water: Soak the vacuum-packed fresh bamboo shoots in room temperature water until they cool to room temperature.

[0075] 7) Refrigeration and preservation: Store the cooled fresh bamboo shoots at 2~8℃ for preservation.

[0076] Comparative Example 2

[0077] A method for processing and preserving fresh bamboo shoots without additives includes the following steps:

[0078] 1) Raw material processing and cutting: Select fresh, tender bamboo shoots that are free from rot, insects, and mechanical damage. After washing, peeling, trimming and removing old roots and coarse fibers, cut them into slices for later use.

[0079] 2) First boiling: Immerse the cut fresh bamboo shoots in clean water, heat to boiling, and then keep simmering for about 15 minutes.

[0080] 3) Cleaning and soaking: Quickly remove the fresh bamboo shoots after the first boil and put them into continuously flowing, circulating clean water for a quick rinse and cooling for 30 minutes. Then soak them in clean water for 120 minutes, changing the water once in between.

[0081] 4) Second boiling: Take out the cooled and soaked fresh bamboo shoots, put them back into clean water and bring to a boil over high heat for 20 minutes.

[0082] 5) Vacuum packaging: After the second boiling, immediately pack the fresh bamboo shoots into aseptic food packaging bags while they are still hot and vacuum seal them.

[0083] 6) Cooling with water: Soak the vacuum-packed fresh bamboo shoots in room temperature water until they cool to room temperature.

[0084] 7) Refrigeration and preservation: Store the cooled fresh bamboo shoots at 2~8℃ for preservation.

[0085] Comparative Example 3

[0086] A method for processing and preserving fresh bamboo shoots without additives includes the following steps:

[0087] 1) Raw material processing and cutting: Select fresh, tender bamboo shoots that are free from rot, insects, and mechanical damage. After washing, peeling, trimming and removing old roots and coarse fibers, cut them into slices for later use.

[0088] 2) First boiling: Immerse the cut fresh bamboo shoots in clean water, heat to boiling, and then keep simmering for about 15 minutes.

[0089] 3) Cleaning and soaking: Quickly remove the fresh bamboo shoots after the first boil and put them into continuously flowing, circulating clean water for a quick rinse and cooling for 30 minutes. Then soak them in clean water for 120 minutes, changing the water once in between.

[0090] 4) Vacuum packaging: After soaking, the fresh bamboo shoots are placed into aseptic food packaging bags and vacuum sealed.

[0091] 5) Refrigeration and preservation: Store the cooled fresh bamboo shoots at 2~8℃ for preservation.

[0092] Comparative Example 4

[0093] A method for processing and preserving fresh bamboo shoots without additives includes the following steps:

[0094] 1) Raw material processing and cutting: Select fresh, tender bamboo shoots that are free from rot, insects, and mechanical damage. After washing, peeling, trimming and removing old roots and coarse fibers, cut them into slices for later use.

[0095] 2) First boiling: Immerse the cut fresh bamboo shoots in water and bring to a boil over high heat for 15 minutes.

[0096] 3) Vacuum packaging: After the second boiling, immediately pack the fresh bamboo shoots into aseptic food packaging bags while they are still hot and vacuum seal them.

[0097] 4) Cooling with water: Soak the vacuum-packed fresh bamboo shoots in room temperature water until they cool to room temperature.

[0098] 5) Refrigeration and preservation: Store the cooled fresh bamboo shoots at 2~8℃ for preservation.

[0099] The quality analysis of the bamboo shoot products prepared in each embodiment and comparative example is as follows:

[0100] 1. Product taste and flavor test.

[0101] The scoring criteria are shown in Table 1 below.

[0102] Table 1 Bamboo Shoot Taste and Flavor Scoring Criteria

[0103]

[0104] 2. After refrigerated storage for 7 days, the tannin content (expressed as mg tannic acid per gram of fresh bamboo shoots) in the bamboo shoot products prepared in the examples and comparative examples was detected according to "GB / T 20574-2006 Determination of Total Flavonoids in Propolis by Spectrophotometric Colorimetric Method" and "GB / T 27985-2011 Determination of Tannins in Feed by Spectrophotometric Method". The results are shown in Table 2.

[0105] Table 2 Performance test results of the examples and comparative examples

[0106]

[0107] In summary, the fresh bamboo shoot processing and preservation method of this invention integrates a complete physical process encompassing color protection, crispness enhancement, sterilization, and packaging. This approach not only completely eliminates the need for additives but also simultaneously achieves excellent color protection, texture solidification, and efficient sterilization of fresh bamboo shoots, resulting in a fresh bamboo shoot product with a crisp and tender texture, natural color, and significantly extended shelf life. The process of this invention is coherent and controllable, making it fully applicable to industrial production lines.

[0108] The technical features of the embodiments described above can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for processing and preserving fresh bamboo shoots without additives, characterized in that, The steps are as follows: Raw material processing and cutting; First boiling: Submerge the chopped fresh bamboo shoots in water, heat to a boil, and then simmer for 10-15 minutes. Cleaning and soaking: After the first boil, remove the fresh bamboo shoots, rinse them with clean water and let them cool, then soak them. Second boiling: Remove the soaked bamboo shoots and put them back into fresh water. Bring to a boil over high heat for 10-15 minutes. ， ; Vacuum packaging: After the second boiling, immediately vacuum seal the package while it is still hot; Cooling with clean water: Place the vacuum-packed fresh bamboo shoots in clean water to cool to room temperature; Refrigeration and preservation: Store the cooled fresh bamboo shoots in the refrigerator.

2. The method for processing and preserving fresh bamboo shoots according to claim 1, characterized in that, In the "raw material processing and cutting" step, fresh, tender bamboo shoots that are free from rot, insect infestation, and mechanical damage are selected, and after washing, peeling, and trimming, they are cut into sections, slices, or strips.

3. The method for processing and preserving fresh bamboo shoots according to claim 1, characterized in that, In the "cleaning and soaking" step, the water is first rinsed and cooled with circulating clean water, and then soaked in clean water.

4. The method for processing and preserving fresh bamboo shoots according to claim 3, characterized in that, In the "cleaning and soaking" step, clean water is used for 10-30 minutes for cleaning and cooling.

5. The method for processing and preserving fresh bamboo shoots according to claim 4, characterized in that, In the "cleaning and soaking" step, after cleaning and cooling, the sample is placed in clean water and soaked for 60-120 minutes.

6. The method for processing and preserving fresh bamboo shoots according to claim 5, characterized in that, During the "cleaning and soaking" step, the water must be changed at least once during the soaking process.

7. The method for processing and preserving fresh bamboo shoots according to claim 1, characterized in that, In the "water cooling" step, the vacuum-packed fresh bamboo shoots are soaked in room temperature water and cooled to room temperature.

8. The method for processing and preserving fresh bamboo shoots according to claim 1, characterized in that, In the "refrigeration and preservation" step, the cooled fresh bamboo shoots are refrigerated and stored at 2-10℃.

9. The method for processing and preserving fresh bamboo shoots according to any one of claims 1 to 8, characterized in that, Between the "water cooling" and "refrigeration preservation" steps, there is also a reheating and cooling step.

10. Bamboo shoots prepared by the fresh bamboo shoot processing and preservation method according to any one of claims 1 to 9.

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