Ready-to-eat bamboo shoot premade dish capable of improving antioxidant activity and preparation method of ready-to-eat bamboo shoot premade dish

Abstract

The invention discloses an instant bamboo shoot prefabricated dish capable of improving antioxidant activity and a preparation method, and relates to the technical field of food processing. The method has the advantages that the vacuum frying method is combined with the irradiation sterilization technology, the antioxidant activity of the instant bamboo shoot prefabricated dish is effectively reserved, the defects that the quality of traditional instant bamboo shoot prefabricated dish is degraded, active substances are prone to being damaged and the like are overcome, large-scale production is supported, no harmful substance residues exist, the product quality can be better controlled, and the production cost is reduced. The development prospect is wide and the market value is huge.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to an instant bamboo shoot pre-cooked dish with improved antioxidant activity and a preparation method thereof. Background Art

[0002] Bamboo shoots are a unique food ingredient, rich in nutrients such as protein, dietary fiber, multiple vitamins, and minerals. They have a fresh, crisp taste and are deeply loved by consumers. In traditional diets, bamboo shoots are often eaten fresh, pickled, or dried. However, with the accelerated pace of life, the demand for convenient and functional foods is increasing, and ready-to-eat bamboo shoots have emerged, providing consumers with a more convenient eating option. Bamboo shoots have a naturally significant antioxidant activity, which is mainly attributed to the various antioxidant components they contain. These components play an important role in scavenging free radicals and inhibiting oxidative reactions. They are rich in phenols, flavonoids, vitamins, and polysaccharides. Vitamins C and E work synergistically, water-soluble and fat-soluble antioxidants complement each other, and polysaccharides activate the body's antioxidant enzyme system. These components work through multiple pathways to help the body resist free radical damage, maintain cell health, and slow the aging process.

[0003] Traditional heat processing leads to loss of antioxidants: Electronic literature review and extensive market research revealed that the current cooking process for ready-to-eat bamboo shoots primarily involves steaming, boiling, and roasting. However, the high temperatures during steaming and boiling destroy some heat-sensitive antioxidants, such as vitamin C. Furthermore, high temperatures can trigger oxidative polymerization of polyphenols in the bamboo shoots, altering their structure and reducing their antioxidant capacity. Furthermore, the high temperatures of frying can oxidize and degrade antioxidants such as unsaturated fatty acids, producing harmful substances like lipid peroxides, significantly reducing their antioxidant activity.

[0004] The harm of traditional sterilization methods on the antioxidant activity of ready-to-eat bamboo shoots: Although traditional sterilization methods (such as high-temperature treatment and the addition of chemical preservatives) can effectively kill microorganisms, they often significantly impair the antioxidant activity of ready-to-eat bamboo shoots. First, high temperatures directly lead to the oxidation or decomposition of heat-labile substances such as vitamin C, polyphenols, and flavonoids. For example, vitamin C is rapidly lost at temperatures above 80°C, and polyphenols undergo polymerization or oxidation reactions at high temperatures, reducing their free radical scavenging ability. Furthermore, high temperatures can disrupt cell structure and rupture plant cell walls, leading to the loss of water-soluble antioxidant components (such as phenolic acids and B vitamins) during subsequent rinsing or soaking. After traditional high-temperature sterilization (121°C for 15 minutes), the vitamin C retention rate of ready-to-eat bamboo shoots is only 50%-60%, and the total phenolic content decreases by 30%-40%. The DPPH free radical scavenging rate drops from 90% of fresh bamboo shoots to 60%-70%, significantly reducing antioxidant activity. Therefore, we propose a ready-to-eat bamboo shoot pre-cooked dish with enhanced antioxidant activity and a preparation method. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems mentioned in the above background technology, and provide an instant bamboo shoot pre-cooked dish with improved antioxidant activity and a preparation method.

[0006] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0007] The invention discloses an instant bamboo shoot pre-cooked dish with enhanced antioxidant activity, which uses fresh bamboo shoots as raw materials.

[0008] A method for preparing an instant bamboo shoot pre-cooked dish with improved antioxidant activity comprises the following steps:

[0009] Step 1: Raw material processing: peel the bamboo shoots, remove the aging parts of the roots, rinse with running water for 3 to 5 minutes, wash away surface impurities and dirt, and ensure that there is no residue;

[0010] Step 2: Cut and shape: Use an automatic slicer to cut the washed bamboo shoots into 4mm thick and 2cm long strips;

[0011] Step 3: Vacuum frying: first add oil, evenly place the pre-treated bamboo shoots into the vacuum frying pan, and use a vacuum pump to reduce the air pressure in the frying pan to 0.06MPa, and continue frying;

[0012] Step 4: Seasoning: Add seasonings, salt, soy sauce, and chili peppers during or after frying, mix and fry evenly, filter and set aside;

[0013] Step 5: Cooling: After frying, release the vacuum, take out the bamboo shoots, and use cooling equipment to blow cold air to quickly cool them to room temperature to prevent residual heat from causing the bamboo shoots to deteriorate in taste and change in color.

[0014] Step 6: Vacuum packaging: After the bamboo shoots cool to room temperature, use food-grade vacuum packaging bags to quantitatively package them, and use a vacuum packaging machine to vacuum seal them to isolate them from air and extend the shelf life;

[0015] Step 7, irradiation sterilization: Use a radiation source to irradiate and sterilize the packaged bamboo shoots to obtain a pre-prepared dish product.

[0016] Furthermore, the frying temperature in the vacuum frying is 80° C., the frying time is 8 minutes, and the vacuum frying pan is equipped with a stirring device, and the stirring speed is 10-15 rpm.

[0017] Furthermore, the vacuum packaging is performed using an automatic vacuum packaging machine using an aluminum foil composite film, and the air pressure parameter of the vacuum packaging machine is 0.01 MPa.

[0018] Furthermore, the radiation source used in the radiation sterilization is a cobalt-60 radiation source, and the radiation dose is 4 kGy.

[0019] A method for preparing an instant bamboo shoot pre-cooked dish with improved antioxidant activity comprises the following steps:

[0020] Step 1: Raw material processing: peel the bamboo shoots, remove the aging parts of the roots, rinse with running water for 3 to 5 minutes, wash away surface impurities and dirt, and ensure that there is no residue;

[0021] Step 2: Cut and shape: Use an automatic slicer to cut the washed bamboo shoots into 4mm thick and 2cm long strips;

[0022] Step 3: Vacuum seal: Place the bamboo shoots into a high-temperature resistant vacuum bag, add appropriate seasonings such as salt, soy sauce, and chili, and use a vacuum packaging machine to remove air and seal.

[0023] Step 4: low temperature cooking: put the sealed bamboo shoots into a constant temperature water bath for cooking;

[0024] Step 5: Cooling: After cooking, remove the bamboo shoots and cool to room temperature;

[0025] Step 6, irradiation sterilization: Use a radiation source to irradiate and sterilize the packaged bamboo shoots to obtain a pre-prepared dish product.

[0026] Furthermore, the low-temperature cooking temperature is 75-85° C., and the heating time is 30-60 minutes.

[0027] A method for preparing an instant bamboo shoot pre-cooked dish with improved antioxidant activity comprises the following steps:

[0028] Step 1: Raw material processing: peel the bamboo shoots, remove the aging parts of the roots, rinse with running water for 3 to 5 minutes, wash away surface impurities and dirt, and ensure that there is no residue;

[0029] Step 2: Cut and shape: Use an automatic slicer to cut the washed bamboo shoots into 4mm thick and 2cm long strips;

[0030] Step 3: Seasoning: Mix well with a small amount of vegetable oil, salt, soy sauce and chili pepper;

[0031] Step 4: Vacuum seal: Place the bamboo shoots into a high-temperature resistant vacuum bag, use a vacuum packaging machine to extract the air and seal;

[0032] Step 5, low temperature baking: put the sealed bamboo shoots into a low temperature oven for baking;

[0033] Step 6: Cooling: After baking, remove the bamboo shoots and cool to room temperature;

[0034] Step 7, irradiation sterilization: Use a radiation source to irradiate and sterilize the packaged bamboo shoots to obtain a pre-prepared dish product.

[0035] Furthermore, the low-temperature baking temperature is 80-100° C., and the baking time is 30-60 minutes.

[0036] The beneficial effects of the present invention are as follows:

[0037] 1. The present invention overcomes the defects of high-temperature bamboo shoot products in traditional pre-prepared dishes in terms of edible quality, flavor and nutrition. During the processing, the bamboo shoots are first vacuum-fried to retain their antioxidant activity, and then combined with irradiation sterilization after the packaging process, which ensures that the pre-prepared dishes have good active substances and also extends their shelf life.

[0038] 2. The present invention also develops a pre-prepared dish of instant bamboo shoots, which supplements the market of pre-prepared dishes and has great market potential.

[0039] 3. The irradiation sterilization of the present invention provides support for the safety and activity of back-end microorganisms, replacing traditional high-temperature sterilization with room-temperature sterilization (4-6kGy dose), avoiding damage to the retained antioxidant components by secondary heat treatment; penetrating sterilization ensures that heat-resistant spores or anaerobic bacteria that may remain after vacuum frying are completely inactivated, extending the shelf life to 18-24 months; low-dose irradiation (<6kGy) causes micro-damage to the cell wall, which can release bound polyphenols and enhance the bioavailability of antioxidants (free polyphenols increase by 10% to 20%); the combination of the two forms a closed "low-temperature processing chain", avoiding the loss of activity caused by multiple high-temperature or chemical treatments in traditional processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a workflow diagram of Example 1 of the present invention;

[0041] Figure 2 This is a workflow diagram of Example 2 of the present invention;

[0042] Figure 3 It is a workflow diagram of Example 3 in the present invention. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0044] The invention provides an instant bamboo shoot pre-cooked dish with improved antioxidant activity, and fresh bamboo shoots are selected as raw materials.

[0045] Example 1

[0046] See also Figure 1The present invention provides a method for preparing an instant bamboo shoot pre-cooked dish with improved antioxidant activity, comprising the following steps:

[0047] Step 1: Raw material processing: peel the bamboo shoots, remove the aging parts of the roots, rinse with running water for 3 to 5 minutes, wash away surface impurities and dirt, and ensure that there is no residue;

[0048] Step 2: Cut and shape: Use an automatic slicer to cut the washed bamboo shoots into 4mm thick and 2cm long strips;

[0049] Step 3, vacuum frying: first add oil, evenly place the pretreated bamboo shoots into a vacuum frying pan, and use a vacuum pump to reduce the air pressure in the frying pan to 0.06MPa, and continue frying. The frying temperature is 80°C, the frying time is 8 minutes, and the vacuum frying pan is equipped with a stirring device with a stirring speed of 10-15rpm. Vacuum frying is mainly to lock the front-end antioxidant activity and avoid the damage of heat-sensitive antioxidants such as vitamin C and polyphenols by high temperature through a low temperature environment (60-80°C). The retention rate is increased to 90% to 95% (only 50% to 60% in traditional processes). Hypoxic conditions inhibit oxidase activity (e.g., polyphenol oxidase activity is reduced by more than 70%), blocking enzymatic browning and oxidation reactions in the early stages of storage. This improves product color and flavor, maintaining the natural light yellow or milky white color of bamboo shoots and avoiding the dark color caused by traditional stir-frying. Furthermore, under low-pressure conditions, water evaporation is accelerated, the stir-frying time is shortened, and the loss of volatile flavor substances (e.g., terpenes and aldehydes) is reduced, preserving the unique fragrance and sweetness of bamboo shoots.

[0050] Step 4: Seasoning: Add seasonings, salt, soy sauce, and chili peppers during or after frying, mix and fry evenly, filter and set aside;

[0051] Step 5: Cooling: After frying, release the vacuum, take out the bamboo shoots, and use cooling equipment to blow cold air to quickly cool them to room temperature to prevent residual heat from causing the bamboo shoots to deteriorate in taste and change in color.

[0052] Step 6, vacuum packaging: After the bamboo shoots cool to room temperature, use food-grade vacuum packaging bags to quantitatively package them, use a vacuum packaging machine to vacuum seal, isolate the air, and extend the shelf life. Use an automatic vacuum packaging machine to use aluminum foil composite film for packaging, and the air pressure parameter of the vacuum packaging machine is 0.01 MPa;

[0053] Step 7: Irradiation Sterilization: The packaged bamboo shoots are irradiated using an irradiation source to produce the finished pre-prepared dish. A cobalt-60 irradiator is used for irradiation sterilization, with a dose of 4 kGy. Combined with nitrogen packaging (residual oxygen <3%), this sterilization suppresses free radicals. Irradiation sterilization supports microbial safety and activity in the back-end, replacing traditional high-temperature sterilization with room-temperature sterilization (4-6 kGy dose) to avoid damage to retained antioxidants caused by secondary heat treatment. Penetrating sterilization ensures that any heat-resistant spores or anaerobic bacteria that may remain after vacuum frying are completely inactivated, extending the shelf life to 18-24 months. Low-dose irradiation (<6 kGy) micro-damages the cell wall, releasing bound polyphenols and increasing the bioavailability of antioxidants (increasing free polyphenols by 10%-20%). This combination forms a closed "low-temperature processing chain," avoiding the loss of activity caused by multiple high-temperature or chemical treatments in traditional processes.

[0054] Example 2

[0055] See also Figure 2 The present invention provides a method for preparing an instant bamboo shoot pre-cooked dish with improved antioxidant activity, comprising the following steps:

[0056] Step 1: Raw material processing: peel the bamboo shoots, remove the aging parts of the roots, rinse with running water for 3 to 5 minutes, wash away surface impurities and dirt, and ensure that there is no residue;

[0057] Step 2: Cut and shape: Use an automatic slicer to cut the washed bamboo shoots into 4mm thick and 2cm long strips;

[0058] Step 3: Vacuum seal: Place the bamboo shoots into a high-temperature resistant vacuum bag, add appropriate seasonings such as salt, soy sauce, and chili, and use a vacuum packaging machine to remove air and seal.

[0059] Step 4: low-temperature cooking: place the sealed bamboo shoots into a constant temperature water bath and cook at 75-85°C for 30-60 minutes;

[0060] Step 5: Cooling: After cooking, remove the bamboo shoots and cool to room temperature;

[0061] Step 6, irradiation sterilization: Use a radiation source to irradiate and sterilize the packaged bamboo shoots to obtain a pre-prepared dish product. The irradiation source for irradiation sterilization is a cobalt-60 irradiation source with an irradiation dose of 4 kGy. Nitrogen packaging (residual oxygen <3%) is used to inhibit the effects of free radicals.

[0062] Example 3

[0063] See also Figure 3 The present invention provides a method for preparing an instant bamboo shoot pre-cooked dish with improved antioxidant activity, comprising the following steps:

[0064] Step 1: Raw material processing: peel the bamboo shoots, remove the aging parts of the roots, rinse with running water for 3 to 5 minutes, wash away surface impurities and dirt, and ensure that there is no residue;

[0065] Step 2: Cut and shape: Use an automatic slicer to cut the washed bamboo shoots into 4mm thick and 2cm long strips;

[0066] Step 3: Seasoning: Mix well with a small amount of vegetable oil, salt, soy sauce and chili pepper;

[0067] Step 4: Vacuum seal: Place the bamboo shoots into a high-temperature resistant vacuum bag, use a vacuum packaging machine to extract the air and seal;

[0068] Step 5, low temperature baking: put the sealed bamboo shoots into a low temperature oven and bake at a temperature of 80-100°C for 30-60 minutes;

[0069] Step 6: Cooling: After baking, remove the bamboo shoots and cool to room temperature;

[0070] Step 7, irradiation sterilization: Use a radiation source to irradiate and sterilize the packaged bamboo shoots to obtain a pre-prepared dish product. The irradiation source for irradiation sterilization is a cobalt-60 irradiation source with an irradiation dose of 4 kGy. Nitrogen packaging (residual oxygen <3%) is used to inhibit the effects of free radicals.

[0071] Experimental Test 1

[0072] The sensory evaluation of Example 1, Example 2 and Example 3 was performed according to Table 1. The cooking methods of different instant bamboo shoots were prepared and the sensory evaluation was performed in six aspects: color, aroma, bitterness, saltiness, umami and taste richness. Ten trained panelists (5 females and 5 males, aged 20-25 years) from Sichuan Agricultural University were tested to evaluate the samples using a sensory standard rating scale. The final score of different items (color, aroma, bitterness, saltiness, umami and taste richness) was calculated as the average of the ten scores.

[0073] Table 1 Sensory evaluation standards for ready-to-eat bamboo shoots dishes

[0074]

[0075]

[0076] Table 2 Sensory evaluation results of Example 1, Example 2 and Example 3

[0077] sample Sensory score Example 1 85±1.51 Example 2 80±1.45 Example 3 79±1.32

[0078] As can be seen from Table 2, the sensory scores of each group are significantly different under different processes. The sensory score of Example 1 is higher than that of Example 2 and Example 3. It can be seen that the process combination of vacuum frying and irradiation sterilization can better maintain the sensory organ and flavor of the pre-prepared dish than the process combination of Example 2 and Example 3; it can also be seen that the flavor and color of the pre-prepared dish of stir-fried instant bamboo shoots are better than those of boiled and baked instant bamboo shoots, which also indirectly shows that the process scheme adopted by the invention can maintain a relatively good process while maintaining good antioxidant and bactericidal effects; it can also be shown that the cooking method of the vacuum frying method not only meets the sensory requirements, but also obtains better flavor evaluation.

[0079] Experimental Test 2

[0080] The antioxidant activity of the samples was determined using metal chelation, reducing power and DPPH free radical scavenging ability as detection indicators.

[0081] According to the above method, after cooking is completed, wipe off the oil and water on the surface of the material and dry it, then grind it into powder and pass it through an 80-mesh sieve, and then measure the physical and chemical indicators.

[0082] Determination of metal chelation: The metal chelation equivalent of Example 1 was 355.17, significantly higher than that of Example 2 (342.20) and Example 3 (324.75). Analysis shows that the optimized formulation and process in Example 1 significantly enhanced the metal chelation ability, effectively chelating free metal ions and inhibiting oxidation reactions.

[0083] Reducing power measurement: The reducing power value of Example 1 was 221.05, significantly higher than that of Example 2 (174.86) and Example 3 (194.22). The synergistic effect of the active ingredients in Example 1 significantly increased the reducing power, indicating that it has a strong electron donation capacity and can effectively scavenge free radicals.

[0084] Determination of DPPH free radical scavenging ability: The DPPH free radical scavenging ability index of Example 1 is 0.90, which is significantly better than that of Example 2 (0.87) and Example 3 (0.77).

[0085]

[0086] As shown in Table 3, the cooking methods in each group showed significant changes under different process conditions. Example 1 performed well in metal chelation, reducing power, and DPPH free radical scavenging rate, and had the strongest overall antioxidant activity. Example 1 was significantly superior to Examples 2 and 3 in terms of metal chelation and reducing power. Example 1 had the best overall antioxidant activity index, indicating higher antioxidant capacity and a longer shelf life.

[0087] In summary, the present invention successfully prepares a ready-to-eat bamboo shoot pre-cooked dish with high antioxidant activity by optimizing the formula and process, and has broad market application prospects.

[0088] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A ready-to-eat bamboo shoot pre-cooked dish with improved antioxidant activity, characterized in that: Fresh bamboo shoots are used as raw materials.

2. A method for preparing an instant bamboo shoot pre-cooked dish with improved antioxidant activity, characterized in that: The steps include: Step 1: Raw material processing: peel the bamboo shoots, remove the aging parts of the roots, rinse with running water for 3 to 5 minutes, wash away surface impurities and dirt, and ensure that there is no residue; Step 2: Cut and shape: Use an automatic slicer to cut the washed bamboo shoots into 4mm thick and 2cm long strips; Step 3: Vacuum frying: first add oil, evenly place the pre-treated bamboo shoots into the vacuum frying pan, and use a vacuum pump to reduce the air pressure in the frying pan to 0.06MPa, and continue frying; Step 4: Seasoning: Add seasonings, salt, soy sauce, and chili peppers during or after frying, mix and fry evenly, filter and set aside; Step 5: Cooling: After frying, release the vacuum, take out the bamboo shoots, and use cooling equipment to blow cold air to quickly cool them to room temperature to prevent residual heat from causing the bamboo shoots to deteriorate in taste and change in color. Step 6: Vacuum packaging: After the bamboo shoots cool to room temperature, use food-grade vacuum packaging bags to quantitatively package them, and use a vacuum packaging machine to vacuum seal them to isolate them from air and extend the shelf life; Step 7, irradiation sterilization: Use a radiation source to irradiate and sterilize the packaged bamboo shoots to obtain a pre-prepared dish product.

3. The method for preparing a ready-to-eat bamboo shoot pre-prepared dish with improved antioxidant activity according to claim 2, wherein: The frying temperature in the vacuum frying is 80° C., the frying time is 8 minutes, and the vacuum frying pan is equipped with a stirring device at a stirring speed of 10 to 15 rpm.

4. The method for preparing a ready-to-eat bamboo shoot pre-cooked dish with improved antioxidant activity according to claim 2, wherein: The vacuum packaging is performed using an automatic vacuum packaging machine using an aluminum foil composite film, and the air pressure parameter of the vacuum packaging machine is 0.01 MPa.

5. The method for preparing a ready-to-eat bamboo shoot pre-cooked dish with improved antioxidant activity according to claim 2, wherein: The radiation source used in the irradiation sterilization is a cobalt-60 radiation source, and the irradiation dose is 4 kGy.

6. A method for preparing an instant bamboo shoot pre-cooked dish with improved antioxidant activity, characterized in that: The steps include: Step 1: Raw material processing: peel the bamboo shoots, remove the aging parts of the roots, rinse with running water for 3 to 5 minutes, wash away surface impurities and dirt, and ensure that there is no residue; Step 2: Cut and shape: Use an automatic slicer to cut the washed bamboo shoots into 4mm thick and 2cm long strips; Step 3: Vacuum seal: Place the bamboo shoots into a high-temperature resistant vacuum bag, add appropriate seasonings such as salt, soy sauce, and chili, and use a vacuum packaging machine to remove air and seal. Step 4: low temperature cooking: put the sealed bamboo shoots into a constant temperature water bath for cooking; Step 5: Cooling: After cooking, remove the bamboo shoots and cool to room temperature; Step 6, irradiation sterilization: Use a radiation source to irradiate and sterilize the packaged bamboo shoots to obtain a pre-prepared dish product.

7. The method for preparing a ready-to-eat bamboo shoot pre-cooked dish with improved antioxidant activity according to claim 6, wherein: The low-temperature cooking temperature is 75-85° C., and the heating time is 30-60 minutes.

8. A method for preparing an instant bamboo shoot pre-cooked dish with improved antioxidant activity, characterized in that: The steps include: Step 1: Raw material processing: peel the bamboo shoots, remove the aging parts of the roots, rinse with running water for 3 to 5 minutes, wash away surface impurities and dirt, and ensure that there is no residue; Step 2: Cut and shape: Use an automatic slicer to cut the washed bamboo shoots into 4mm thick and 2cm long strips; Step 3: Seasoning: Mix well with a small amount of vegetable oil, salt, soy sauce and chili pepper; Step 4: Vacuum seal: Place the bamboo shoots into a high-temperature resistant vacuum bag, use a vacuum packaging machine to extract the air and seal; Step 5, low temperature baking: put the sealed bamboo shoots into a low temperature oven for baking; Step 6: Cooling: After baking, remove the bamboo shoots and cool to room temperature; Step 7, irradiation sterilization: Use a radiation source to irradiate and sterilize the packaged bamboo shoots to obtain a pre-prepared dish product.

9. The method for preparing a ready-to-eat bamboo shoot pre-cooked dish with improved antioxidant activity according to claim 8, wherein: The low-temperature baking temperature is 80-100° C., and the baking time is 30-60 minutes.

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