An expanded microparticle and its application in the preparation of expanded dendrocalamus latiflorus shoot
Patent Information
- Application Number
- CN202610885286.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-18
- Publication Date
- 2026-09-29
AI Technical Summary
[0003]现有麻竹笋膨化加工多依赖笋体自身含水量和纤维组织在油炸过程中的自然膨化，但麻竹笋组织内纤维束排列方向性强，孔隙分布不均，导致油炸时热量传导和水汽释放难以同步进行
（1）通过外源膨化微粒诱导麻竹笋在油炸过程中形成稳定微孔结构，使麻竹笋膨化不再单纯依赖自身致密纤维组织的自然膨胀，能够降低麻竹笋片或麻竹笋丝中心发硬、边缘焦黄和局部塌缩的问题。
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Figure CN122827366A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of food processing technology, specifically relating to a puffed microparticle and its application in the preparation of puffed bamboo shoots. Background Technology
[0002] Bamboo shoots have a relatively thick flesh, with prominent fiber bundles and vascular bundles, especially those near the base or at higher maturity, where the tissue structure is even denser. The preparation of ready-to-eat puffed bamboo shoot snacks typically involves steps such as color protection, bitterness removal, seasoning, pre-drying, and deep-frying / puffing. During deep-frying / puffing, the internal moisture of the bamboo shoots rapidly vaporizes and migrates outwards in a high-temperature oil phase environment. If there are insufficient channels for moisture migration or inadequate internal support, problems such as localized collapse, hardening, lack of crispness in the center, browning at the edges, and uneven puffing can easily occur.
[0003] Current puffing processing of bamboo shoots largely relies on the natural puffing of the shoot's own moisture content and fibrous tissue during frying. However, the strong directional arrangement of fiber bundles and uneven pore distribution within the bamboo shoot tissue make it difficult for heat conduction and moisture release to occur simultaneously during frying. To achieve a crispier texture, it is often necessary to increase the frying temperature or extend the frying time. However, high-temperature and long-term processing can easily lead to darkening of color, loss of bamboo shoot aroma, increased oil absorption, and affect product stability.
[0004] Furthermore, when ordinary starch, flour, or leavening powder is directly added to the seasoning system of bamboo shoots, it usually only stays on the surface of the shoot and is difficult to penetrate or embed into the interstitial spaces of the vascular bundles. In the early stages of frying, it easily absorbs water and gelatinizes or detaches, failing to sustain its heat transfer, pressure release, and supporting functions. Therefore, how to improve the heat transfer, moisture release, and pore formation during the frying and puffing process of bamboo shoots without significantly altering their original flavor is a technical problem that needs to be solved in the processing of puffed bamboo shoot products. Summary of the Invention
[0005] The purpose of this invention is to provide puffed microparticles and their application in the preparation of puffed bamboo shoots. The puffed microparticles, with edible starch, plant protein, and dietary fiber as a composite framework, are formed into particles with a porous structure and elastic support after moisture conditioning, granulation, pregelatinization, and instantaneous puffing. These puffed microparticles can be compounded with bamboo shoot slices or shreds that have undergone color protection, bittering removal, and flavoring. They are dispersed and embedded in the surface of the bamboo shoot and the interstitial spaces of the vascular bundles through stirring, tumbling, or vacuum adsorption. During subsequent frying and puffing, they act as heat transfer nodes, moisture release channels, and pore-forming centers, promoting rapid moisture migration within the bamboo shoot and thus reducing shrinkage, hardening, and uneven puffing.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a puffed microparticle, wherein the puffed microparticle comprises a composite skeleton formed by edible starch, plant protein and dietary fiber, and the composite skeleton is subjected to humidification, granulation, pregelatinization and instant puffing treatment to form microparticles with porous structure and elastic support function; The puffed microparticles are used to combine with bamboo shoot slices or shreds that have been color-protected, debittered, and flavored, and are dispersed on the surface and in the interstitial spaces of the bamboo shoot slices or shreds during the frying and puffing process to promote the formation of a uniform microporous structure in the bamboo shoot tissue.
[0007] The expanded microparticles comprise the following components by weight: The ingredients are: 45-70 parts edible starch, 8-25 parts plant protein, 10-30 parts dietary fiber, 3-12 parts pregelatinized starch, 0.5-5 parts edible colloid, 2-10 parts bamboo shoot powder, and 18-35 parts water.
[0008] The edible starch is one or more of corn starch, tapioca starch, potato starch, and rice starch; the plant protein is one or more of soy protein isolate, pea protein, wheat protein, and zein; the dietary fiber is one or more of bamboo shoot dietary fiber, oat fiber, citrus fiber, resistant dextrin, and microcrystalline cellulose; and the edible colloid is one or more of sodium carboxymethyl cellulose, xanthan gum, guar gum, sodium alginate, and low-ester pectin.
[0009] The bamboo shoot powder is a powder obtained by washing, color-protecting, drying, and pulverizing byproducts generated during the processing of bamboo shoots, such as the shoot tips, the edible inner layer of the shoot shell, old shoots, or trimmed scraps. The addition of bamboo shoot powder not only enables the resource utilization of bamboo shoot processing byproducts, but also, due to its content of natural dietary fiber, polysaccharides, and bamboo shoot flavor precursors, helps enhance the homology and compatibility between the puffed microparticles and the bamboo shoot tissue, and improves the flavor harmony of the final puffed bamboo shoot products.
[0010] The expanded microparticles have a D50 particle size of 80-600 μm, a D90 particle size of no more than 1000 μm, a moisture content of 4-10 wt%, and a bulk density of 0.18-0.55 g / cm³. 3 By controlling the D50 particle size and moisture content of the puffed microparticles, the puffed microparticles form a steam core in the early stage of frying and maintain structural strength during the frying and puffing process, thus delaying the complete gelatinization or collapse of the particles.
[0011] Preferably, the expanded microparticles have a D50 particle size of 150-300 μm, a moisture content of 5-8 wt%, and a bulk density of 0.25-0.42 g / cm³. 3 .
[0012] The porous structure includes open pores and closed pores with a pore size of 5-50 μm; the open pores form water vapor pressure release channels during the frying and puffing process, and the closed pores serve as the pore-forming center; the puffed microparticles have a volume expansion rate of 1.5-3 times during the frying and puffing process, and form a reverse support with the volume shrinkage of the bamboo shoot tissue to maintain the puffed shape of the bamboo shoot slices or bamboo shoot shreds.
[0013] A method for preparing expanded microparticles includes the following steps: Step 1: Mix edible starch, plant protein, dietary fiber, pregelatinized starch, edible colloids and bamboo shoot powder to obtain a dry powder mixture; Step 2: Add water to the dry powder mixture to adjust the moisture content of the material to 18-35 wt%. After stirring evenly, granulate the mixture to obtain wet microparticles. Step 3: Pregelatinize the wet microparticles to partially gelatinize the edible starch and form a complex framework with plant protein and dietary fiber to obtain pregelatinized microparticles. Step 4: The pregelatinized microparticles are subjected to instantaneous puffing treatment to form a porous structure inside, and then dried, cooled and sieved to obtain the puffed microparticles.
[0014] Further, in step two, the granulation is performed using a twin-screw extrusion granulation method, with an extrusion die temperature of 60-85℃; in step three, the pregelatinization treatment temperature is 75-105℃, and the treatment time is 3-20 min; in step four, the instantaneous puffing treatment is extrusion puffing, differential pressure instantaneous puffing, or hot air instantaneous puffing, with a puffing temperature of 120-190℃ and a puffing time of 5-90 s; the drying temperature is 45-75℃, and after drying, the puffed microparticles are sieved to retain a particle size range of 80-800 μm, preferably retaining a particle size range of 150-500 μm.
[0015] The application of the puffed microparticles in the preparation of puffed bamboo shoots is as follows: the puffed microparticles are compounded with bamboo shoot slices or shreds that have undergone color protection, bitterness removal, and flavoring. The puffed microparticles are dispersed and embedded in the surface and vascular bundle gaps of the bamboo shoot slices or shreds by stirring, tumbling, or vacuum adsorption, and then fried and puffed. During the frying and puffing process, the puffed microparticles act as heat transfer nodes, water vapor depressurization channels, and pore-forming centers, promoting the rapid migration of water inside the bamboo shoots and reducing the collapse, hardening, and uneven puffing phenomena caused by the dense fiber structure of the bamboo shoots.
[0016] A method for preparing puffed bamboo shoots includes the following steps: S1: Peel, trim, slice or shred fresh bamboo shoots to obtain bamboo shoot slices or bamboo shoot shreds; S2: Treat the sliced or shredded bamboo shoots for color protection and bitterness removal, then drain after cooling; S3: Place the color-protected and debittered bamboo shoot slices or shredded bamboo shoots into the seasoning liquid for seasoning to obtain seasoned bamboo shoots; S4: Add the puffed microparticles to the seasoned bamboo shoots and mix them by stirring, tumbling or vacuum adsorption to disperse and embed the puffed microparticles into the surface and vascular bundle tissue gaps of the seasoned bamboo shoots; S5: The seasoned bamboo shoots compounded with puffed microparticles are pre-dried at variable temperature. First, they are dried with hot air at 40-50℃ to a moisture content of 45-55wt%, and then dried at 55-70℃ to a moisture content of 20-45wt%, preferably to a moisture content of 28-35wt%. S6: Deep-fry the pre-dried seasoned bamboo shoots until puffed. The frying temperature is 140-180℃ and the frying time is 30-240s. S7: After deep-frying and puffing, the bamboo shoots are de-oiled, cooled, and packaged to obtain puffed bamboo shoot products; In step S4, the amount of puffed microparticles added is 0.5-8 wt% of the weight of the seasoned bamboo shoots, preferably 1.5-4 wt%.
[0017] Compared with existing technologies, it has the following advantages: (1) By inducing the formation of a stable microporous structure in bamboo shoots during frying through exogenous puffing microparticles, the puffing of bamboo shoots no longer relies solely on the natural expansion of their own dense fibrous tissue, which can reduce the problems of hardening in the center, yellowing at the edges and local collapse of bamboo shoot slices or shreds.
[0018] (2) The puffed microparticles of the present invention use edible starch, plant protein and dietary fiber as a composite skeleton, which has both porous structure and elastic support. In the early stage of frying, they can form a steam core, and in the middle and late stages of frying, they can serve as a water vapor pressure release channel and a pore center, which is beneficial to improving the puffing degree and crispness.
[0019] (3) By controlling the particle size, moisture content, bulk density and pore size distribution of the puffed microparticles D50, the present invention enables the microparticles to enter the interstitial space of bamboo shoot tissue, without the microparticles becoming too small and failing to gelatinize quickly, or the microparticles becoming too large and affecting the taste and appearance of the product.
[0020] (4) The present invention uses stirring, tumbling or vacuum adsorption to embed the puffed microparticles into the surface of bamboo shoot slices or bamboo shoot filaments and the gaps in the vascular bundle tissue. Compared with simple powdering or surface adhesion, this method is more conducive to forming stable support points.
[0021] (5) In the variable-temperature pre-drying process adopted in this invention, the first stage of low-temperature drying mainly drives the internal moisture of the material to migrate outward. During this process, the water containing dissolved flavoring ingredients and soluble solids can provide liquid bridges for the combination of puffed microparticles and bamboo shoot tissue, forming a stronger physical interlocking after drying. At the same time, slow drying reduces surface hardening and crust formation. The second stage of medium-temperature drying forms a skin with a certain degree of flexibility and strength on the surface of the material. This skin can hold the steam pressure generated inside during subsequent frying. When the pressure exceeds the threshold, it achieves overall and uniform puffing, rather than disordered cracking. Compared with constant-temperature drying, variable-temperature pre-drying can form a moisture gradient and structural gradient that are more suitable for frying and puffing. Attached Figure Description
[0022] Figure 1 Comparative scanning electron microscope (SEM) images of puffed microparticles in Example 3, ordinary pregelatinized microparticles in Comparative Example 2, and ordinary bamboo shoot powder in Comparative Example 5.
[0023] Figure 2 Comparison of cross-sectional scanning electron microscopy images of puffed microparticles embedded in the vascular bundles of bamboo shoots in Example 3 with those of small-diameter puffed microparticles in Comparative Example 3 and ordinary bamboo shoot powder in Comparative Example 5.
[0024] Figure 3 Comparative images of the cross-sectional pore structure of fried and puffed bamboo shoots in Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 4 using scanning electron microscopy.
[0025] Figure 4 Comparison of low-field NMR T2 relaxation spectra of bamboo shoots during pre-drying and frying puffing processes in Example 3 and Comparative Example 4.
[0026] Figure 5 This is a diagram of the product prepared in an application example of the present invention. Detailed Implementation
[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0028] Please see Figures 1-5 This invention provides a technical solution for puffed microparticles and their application in the preparation of puffed bamboo shoots: In this embodiment of the invention, bamboo shoot powder can be obtained from the bamboo shoot head, the edible inner layer of the bamboo shoot shell, old bamboo shoots, or trimmed scraps produced during the processing of bamboo shoots. After washing, the bamboo shoot powder is soaked in a color-protecting solution containing 0.1wt% citric acid and 0.05wt% ascorbic acid for 5 minutes, and then dried with hot air at 60°C until the moisture content is less than 8wt%. The powder is then pulverized and passed through an 80-mesh sieve.
[0029] All raw materials and additives used in this invention shall comply with the relevant regulations and requirements of GB 2760 "National Food Safety Standard for the Use of Food Additives" and GB 14880 "National Food Safety Standard for the Use of Food Fortifiers"; the puffed bamboo shoot products obtained shall comply with the provisions of GB 17401 "National Food Safety Standard for Puffed Foods" and GB / T22699 "General Rules for the Quality of Puffed Foods".
[0030] Example 1 An expanded microparticle and its application in the preparation of expanded bamboo shoots include the following steps: S1: Weigh 45 parts corn starch, 8 parts soy protein isolate, 10 parts bamboo shoot dietary fiber, 3 parts pregelatinized starch, 0.5 parts sodium carboxymethyl cellulose and 2 parts bamboo shoot powder, mix them evenly to obtain a dry powder mixture.
[0031] S2: Add 18 parts of water to the dry powder mixture to adjust the moisture content of the material to 18wt%. After stirring for 20 minutes, granulate by twin-screw extrusion with an extrusion die temperature of 60℃ to obtain wet microparticles.
[0032] S3: The wet microparticles are pregelatinized at 75°C for 3 minutes to partially gelatinize the starch and form a complex framework with plant protein and dietary fiber, thus obtaining pregelatinized microparticles.
[0033] S4: The pregelatinized microparticles were subjected to instantaneous hot air puffing at 120℃ for 90s, then dried at 45℃, cooled, and sieved to obtain D50 particles with a diameter of 82μm, a moisture content of 4.2wt%, and a bulk density of 0.53g / cm³. 3 The expanded microparticles have pore sizes mainly ranging from 5 to 12 μm.
[0034] S5: Peel and trim fresh bamboo shoots and cut them into slices about 3mm thick. Place the bamboo shoot slices in a color-protecting and debittering solution containing 0.10wt% citric acid, 0.08wt% ascorbic acid and 0.5wt% salt, treat at 85℃ for 8 minutes, and drain after cooling.
[0035] S6: Place the color-protected and bitter-removed bamboo shoot slices in a seasoning liquid for seasoning. The seasoning liquid includes salt, white sugar, yeast extract and bamboo shoot extract. After seasoning, seasoned bamboo shoots are obtained.
[0036] S7: Add the puffed microparticles to the seasoned bamboo shoots at a rate of 0.5 wt% of the bamboo shoot weight, and mix for 5 minutes by stirring to disperse the puffed microparticles on the surface of the bamboo shoot slices and in some interstitial spaces.
[0037] S8: The seasoned bamboo shoots with puffed microparticles are pre-dried at variable temperature. First, they are dried with hot air at 40°C to a moisture content of 55wt%, and then dried at 55°C to a moisture content of 45wt%.
[0038] S9: The pre-dried seasoned bamboo shoots are deep-fried and puffed at a temperature of 140℃ for 240 seconds. After frying, the oil is removed by centrifugation, the product is cooled and packaged to obtain puffed bamboo shoot products.
[0039] Example 2 An expanded microparticle and its application in the preparation of expanded bamboo shoots include the following steps: S1: Weigh 50 parts tapioca starch, 12 parts pea protein, 15 parts bamboo shoot dietary fiber, 5 parts pregelatinized starch, 1.5 parts xanthan gum and 4 parts bamboo shoot powder, mix them evenly to obtain a dry powder mixture.
[0040] S2: Add 22 parts of water to the dry powder mixture to adjust the moisture content of the material to 22 wt%. After stirring for 25 minutes, granulate by twin-screw extrusion with an extrusion die temperature of 68℃ to obtain wet microparticles.
[0041] S3: Pregelatinize the wet microparticles at 85°C for 8 minutes to obtain pregelatinized microparticles.
[0042] S4: The pregelatinized microparticles were extruded and puffed at 145℃ for 45s, then dried at 55℃, cooled, and sieved to obtain D50 particles with a diameter of 155μm, a moisture content of 5.3wt%, and a bulk density of 0.41g / cm³. 3 The expanded microparticles have pore sizes mainly distributed between 12-25 μm.
[0043] S5: Peel and trim fresh bamboo shoots and cut them into strips. Place the bamboo shoot strips in a color-protecting and debittering solution containing 0.15wt% citric acid, 0.10wt% ascorbic acid and 0.8wt% salt, treat at 88℃ for 7 minutes, and drain after cooling.
[0044] S6: Place the color-protecting and bitterness-removing bamboo shoot strips in the seasoning liquid to season them, thus obtaining seasoned bamboo shoots.
[0045] S7: Add the puffed microparticles to the seasoned bamboo shoots at a rate of 1.5 wt% of the bamboo shoot weight, and mix by tumbling for 8 minutes to disperse the puffed microparticles and embed them into the surface of the bamboo shoot filaments and the interstitial spaces of the vascular bundles.
[0046] S8: The seasoned bamboo shoots with puffed microparticles are pre-dried at variable temperature. First, they are dried with hot air at 45°C to a moisture content of 50wt%, and then dried at 60°C to a moisture content of 35wt%.
[0047] S9: The pre-dried seasoned bamboo shoots are deep-fried and puffed at a temperature of 155℃ for 150 seconds. After frying, the oil is removed by centrifugation, the product is cooled and packaged to obtain puffed bamboo shoot products.
[0048] Example 3 An expanded microparticle and its application in the preparation of expanded bamboo shoots include the following steps: S1: Weigh 58 parts potato starch, 16 parts soy protein isolate, 20 parts bamboo shoot dietary fiber, 7 parts pregelatinized starch, 2.5 parts sodium alginate and 6 parts bamboo shoot powder, mix them evenly to obtain a dry powder mixture.
[0049] S2: Add 26 parts of water to the dry powder mixture to adjust the moisture content to 26 wt%. After stirring for 30 minutes, granulate by twin-screw extrusion with an extrusion die temperature of 72℃ to obtain wet microparticles.
[0050] S3: The wet microparticles are pregelatinized at 90℃ for 12 minutes to partially gelatinize the edible starch and form a complex framework with plant protein and dietary fiber to obtain pregelatinized microparticles.
[0051] S4: The pregelatinized microparticles were subjected to instantaneous pressure differential puffing at 160℃ for 30s, then dried at 60℃, cooled, and sieved to obtain D50 particles with a diameter of 220μm, a moisture content of 6.6wt%, and a bulk density of 0.32g / cm³. 3 The expanded microparticles have an opening pore size mainly distributed in the range of 18-35 μm, and a volume expansion rate of 2.4 times.
[0052] S5: Peel and trim fresh bamboo shoots and cut them into slices about 3mm thick. Place the bamboo shoot slices in a color-protecting and debittering solution containing 0.20wt% citric acid, 0.12wt% ascorbic acid and 1.0wt% salt, treat at 90℃ for 6 minutes, and drain after cooling.
[0053] S6: After color protection and debittering, the bamboo shoot slices are placed in a seasoning liquid for seasoning. The seasoning liquid includes salt, white sugar, yeast extract, bamboo shoot extract and spice extract. Seasoned bamboo shoots are obtained after seasoning.
[0054] S7: Add the puffed microparticles to the seasoned bamboo shoots at a rate of 3.0 wt% of the bamboo shoot weight. Mix them by vacuum adsorption at a vacuum degree of -0.08 MPa for 6 minutes. Then let them stand at normal pressure for 10 minutes to disperse the puffed microparticles and embed them into the surface of the seasoned bamboo shoot slices and the interstitial spaces of the vascular bundles.
[0055] S8: The seasoned bamboo shoots with puffed microparticles are pre-dried at variable temperature. First, they are dried with hot air at 45℃ to a moisture content of 50wt%, and then dried at 62℃ to a moisture content of 31wt%.
[0056] S9: The pre-dried seasoned bamboo shoots are deep-fried and puffed at a temperature of 160℃ for 120 seconds. After frying, the oil is removed by centrifugation, the product is cooled and packaged to obtain puffed bamboo shoot products.
[0057] The structure of the expanded microparticles obtained in this embodiment is as follows: Figure 1 As shown, it has obvious open and closed pores inside; the expanded microparticles are embedded in the interstitial spaces of the vascular bundles of bamboo shoots as follows. Figure 2 As shown; the process of water vapor migrating along the openings and interfacial gaps during frying and puffing, inducing pore formation, is as follows: Figure 3 As shown.
[0058] Example 4 An expanded microparticle and its application in the preparation of expanded bamboo shoots include the following steps: S1: Weigh 64 parts rice starch, 20 parts wheat protein, 25 parts oat fiber, 10 parts pregelatinized starch, 4 parts low-ester pectin and 8 parts bamboo shoot powder, mix them evenly to obtain a dry powder mixture.
[0059] S2: Add 31 parts of water to the dry powder mixture to adjust the moisture content to 31 wt%. After stirring for 35 minutes, granulate by twin-screw extrusion with an extrusion die temperature of 80℃ to obtain wet microparticles.
[0060] S3: Pregelatinize the wet microparticles at 98℃ for 16 min to obtain pregelatinized microparticles.
[0061] S4: The pregelatinized microparticles were extruded and puffed at 175℃ for 15s, then dried at 70℃, cooled, and sieved to obtain D50 particles with a diameter of 300μm, a moisture content of 7.8wt%, and a bulk density of 0.27g / cm³. 3 The expanded microparticles have pore sizes mainly distributed between 25-42 μm.
[0062] S5: Peel and trim fresh bamboo shoots and cut them into strips. Place the bamboo shoot strips in a color-protecting and debittering solution containing 0.25wt% citric acid, 0.15wt% ascorbic acid and 1.2wt% salt, and treat at 92℃ for 5 minutes. After cooling, drain the water.
[0063] S6: Place the color-protecting and bitterness-removing bamboo shoot strips in the seasoning liquid to season them, thus obtaining seasoned bamboo shoots.
[0064] S7: Add the puffed microparticles to the seasoned bamboo shoots at a rate of 4.0 wt% of the bamboo shoot weight, and mix by tumbling for 10 minutes to disperse the puffed microparticles and embed them into the surface of the bamboo shoot filaments and the interstitial spaces of the vascular bundles.
[0065] S8: The seasoned bamboo shoots with puffed microparticles are pre-dried at variable temperature. First, they are dried with hot air at 50°C to a moisture content of 45wt%, and then dried at 65°C to a moisture content of 28wt%.
[0066] S9: The pre-dried seasoned bamboo shoots are deep-fried and puffed at a temperature of 170℃ for 80 seconds. After frying, the oil is removed by centrifugation, cooled and packaged to obtain puffed bamboo shoot products.
[0067] Example 5 An expanded microparticle and its application in the preparation of expanded bamboo shoots include the following steps: S1: Weigh 70 parts corn starch, 25 parts zein, 30 parts microcrystalline cellulose, 12 parts pregelatinized starch, 5 parts guar gum and 10 parts bamboo shoot powder, mix them evenly to obtain a dry powder mixture.
[0068] S2: Add 35 parts of water to the dry powder mixture to adjust the moisture content to 35 wt%. After stirring for 40 minutes, granulate by twin-screw extrusion with an extrusion die temperature of 85℃ to obtain wet microparticles.
[0069] S3: Pregelatinize the wet microparticles at 105℃ for 20 min to obtain pregelatinized microparticles.
[0070] S4: The pregelatinized microparticles were subjected to instantaneous pressure differential puffing at 190℃ for 5s, then dried at 75℃, cooled, and sieved to obtain D50 particles with a diameter of 590μm, a moisture content of 9.7wt%, and a bulk density of 0.20g / cm³. 3 The expanded microparticles have pore sizes mainly distributed between 35-50 μm.
[0071] S5: Peel and trim fresh bamboo shoots and cut them into slices about 4mm thick. Place the bamboo shoot slices in a color-protecting and debittering solution containing 0.30wt% citric acid, 0.20wt% ascorbic acid and 1.5wt% salt, treat at 95℃ for 3 minutes, and drain after cooling.
[0072] S6: Place the color-protecting and bitterness-removing bamboo shoot slices in the seasoning liquid to season them, thus obtaining seasoned bamboo shoots.
[0073] S7: Add the puffed microparticles to the seasoned bamboo shoots at a rate of 8.0 wt% of the bamboo shoot mass. Mix them by vacuum adsorption at a vacuum degree of -0.08 MPa for 8 minutes. Then let them stand at normal pressure for 10 minutes to disperse the puffed microparticles and embed them into the surface of the seasoned bamboo shoots and the interstitial spaces of the vascular bundles.
[0074] S8: The seasoned bamboo shoots with puffed microparticles are pre-dried at variable temperature. First, they are dried with hot air at 50°C to a moisture content of 45wt%, and then dried at 70°C to a moisture content of 20wt%.
[0075] S9: The pre-dried seasoned bamboo shoots are deep-fried and puffed at a temperature of 180℃ for 30 seconds. After frying, the oil is removed by centrifugation, the product is cooled and packaged to obtain puffed bamboo shoot products.
[0076] Comparative Example 1: No puffed microparticles were added, and the remaining conditions for color protection, debittering, flavoring, pre-drying, frying puffing, and deoiling were the same as in Example 3.
[0077] In Comparative Example 2, the added microparticles were not subjected to instantaneous puffing treatment, but were simply humidified, granulated, pregelatinized, dried and sieved to obtain ordinary pregelatinized microparticles. All other conditions were the same as in Example 3.
[0078] In Comparative Example 3, the added puffed microparticles, after being crushed and sieved, had a D50 particle size of 50 μm, which is lower than the range specified in this invention. The other microparticle formulations, pregelatinization, puffing, drying, compounding, and frying conditions were the same as in Example 3.
[0079] Comparative Example 4 did not use variable temperature pre-drying, but was directly dried with hot air at 60°C to a moisture content of 31wt%, with all other conditions being the same as in Example 3.
[0080] Comparative Example 5 uses ordinary bamboo shoot powder of the same mass instead of puffed microparticles. The ordinary bamboo shoot powder is not subjected to humidification, granulation, pregelatinization and instant puffing treatment. All other conditions are the same as in Example 3.
[0081] Performance testing I. Performance Testing of Puffed Microparticles 1. Particle size distribution: The D50 and D90 particle sizes of the expanded microparticles were determined using a laser particle size analyzer.
[0082] 2. Moisture content: The moisture content was determined in accordance with GB 5009.3 "National Food Safety Standard - Determination of Moisture in Food".
[0083] 3. Pore size and pore morphology: The cross-section of the expanded microparticles was observed using a scanning electron microscope, and the pore size range of open and closed pores was statistically analyzed using image analysis software.
[0084] 4. Bulk density: Take a certain volume of expanded microparticles, let them fill a graduated cylinder naturally, weigh them, and then calculate the bulk density.
[0085] 5. Water absorption capacity: Weigh 1.00g of expanded microparticles, add 20mL of distilled water, let stand at 25℃ for 30min, centrifuge to remove free water, and weigh the wet sample. Water absorption ratio = wet sample mass / dry sample mass.
[0086] 6. Oil absorption capacity: Weigh 1.00g of puffed microparticles, add 20mL of soybean oil, let stand at 25℃ for 30min, centrifuge to remove free oil, and weigh the sample mass after oil absorption. Oil absorption ratio = sample mass after oil absorption / dry sample mass.
[0087] 7. Glass transition temperature Tg: The glass transition temperature of the pregelatinized and dried puffed microparticle sample was determined using a differential scanning calorimeter at a heating rate of 10℃ / min.
[0088] 8. Elastic recovery rate: Take a particle bed sample and place it on the texture analyzer platform. Compress it to 30% and hold it for 5 seconds, then unload it and let it stand for 60 seconds. Elastic recovery rate = unloaded recovery height / initial height × 100%.
[0089] Table 1. Test results of the properties of the expanded microparticles. As shown in Table 1, the puffed microparticles prepared in Examples 1-5 all exhibit good water absorption, oil absorption, and elastic recovery properties, indicating that they can adsorb some of the seasoning liquid during the seasoning compounding stage and form local heat transfer nodes and steam cores during the frying stage. Example 3, with a water absorption ratio of 3.4 g / g, an oil absorption ratio of 1.8 g / g, a Tg of 96℃, and an elastic recovery rate of 76%, demonstrates that it can maintain a certain structural strength in the early stages of frying, preventing immediate complete gelatinization or collapse, thus facilitating its elastic support, pressure relief, and pore-forming functions. Comparative Example 2, without instantaneous puffing treatment, has an insufficient pore structure and a low elastic recovery rate; Comparative Example 5 uses ordinary bamboo shoot powder, which lacks a stable particle structure and porous framework, making it difficult to serve as a heat transfer node and support center.
[0090] II. Performance Testing of Puffed Bamboo Shoot Products 1. Moisture content: The moisture content was determined in accordance with GB 5009.3 "National Food Safety Standard - Determination of Moisture in Food".
[0091] 2. Oil content: The oil content was determined in accordance with GB 5009.6 "National Food Safety Standard - Determination of Fat in Food".
[0092] 3. Quality evaluation of puffed foods: The appearance, texture and sensory quality of the products shall be evaluated in accordance with GB / T 22699 "General Rules for Quality of Puffed Foods"; the safety requirements for prepackaged products shall be controlled in accordance with GB 17401 "National Food Safety Standard for Puffed Foods".
[0093] 4. Expansion degree: The apparent volume of the samples before and after frying was determined by the volume displacement method. Expansion degree = volume of sample after frying / volume of sample before frying. Each group of samples was measured 10 times and the average value was taken.
[0094] 5. Hardness and brittleness: Three-point bending tests were performed using a texture analyzer. The probe was pressed down at a speed of 1.0 mm / s. Hardness was expressed as the maximum breaking force of the first peak, and brittleness was expressed as the number of breaking peaks. Each sample was tested 10 times, and the average value was taken.
[0095] 6. Color difference: The L×, a×, and b× values of the fried and puffed samples were measured using a colorimeter. The total color difference ΔE was calculated using unfried seasoned bamboo shoots as a reference. The smaller the ΔE, the better the color retention.
[0096] 7. Porosity: The cross-section of puffed bamboo shoots was taken, and the pore area ratio was calculated by image analysis after microscopic photography. Five fields of view were measured for each group of samples, and the average value was taken.
[0097] 8. Particle embedding rate: Take the cross-section of the unfried sample after compounding, observe it under a microscope and count the number of puffed particles embedded in the interstitial space of vascular bundles or surface cracks per unit area. Particle embedding rate = number of embedded particles / total number of observed particles × 100%.
[0098] 9. Sensory evaluation: Ten trained evaluators will be organized to score the product based on five aspects: color, aroma, crispness, oiliness, and uniformity of texture. The maximum score is 100 points, and the average score will be taken.
[0099] Table 2 Performance test results of puffed bamboo shoots in the examples and comparative examples As shown in Table 2, Examples 1-5 all successfully prepared puffed bamboo shoot products with a relatively light and brittle texture and a relatively uniform pore structure. Among them, Example 3 used puffed microparticles with a D50 particle size of 220 μm, a moisture content of 6.6 wt%, and a volume expansion rate of 2.4 times, combined with vacuum adsorption and variable temperature pre-drying processes. The resulting product achieved a puffing degree of 1.89 times, a hardness reduced to 10.6 N, a brittleness peak number of 35, a porosity of 49.8%, and a sensory score of 93.0 points, demonstrating the best overall performance.
[0100] Compared with Example 3, Comparative Example 1 did not add puffed microparticles, and the puffing degree was only 1.22 times, the hardness was 28.5 N, and the porosity was 21.4%. This shows that when relying solely on the tissue of bamboo shoots for frying and puffing, it is difficult to form a stable and uniform microporous structure, and hardening and collapse are likely to occur.
[0101] Comparative Example 2 added ordinary pregelatinized microparticles that had not undergone instantaneous puffing treatment. Although exogenous particles were added, they lacked sufficient open and closed pore structures and could not effectively serve as water vapor pressure relief channels and pore-forming centers. Therefore, the degree of puffing, brittleness, and porosity were significantly lower than those of Example 3.
[0102] In Comparative Example 3, the puffed microparticles D50 had a particle size of 50 μm, which is lower than the range specified in this invention. The particles tend to absorb water and gelatinize quickly during the seasoning and frying process, making it difficult to form stable support points in the interstitial spaces of the vascular bundles of bamboo shoots. As a result, both the degree of puffing and the crispness are reduced.
[0103] Comparative Example 4 did not employ variable-temperature pre-drying but instead directly dried at a constant temperature to the same moisture content. Although the final moisture content was close to that of Example 3, the slow moisture migration and liquid bridge interlocking process at low temperatures was lacking during the constant-temperature drying process, as was the structural gradient for forming a flexible outer skin formed in the subsequent medium-temperature stage. Therefore, the internal steam retention capacity decreased during frying, making it more prone to localized cracking and disordered pressure release. The product porosity, puffing degree, and sensory score were all significantly lower than those of Example 3.
[0104] Comparative Example 5 uses ordinary bamboo shoot powder instead of puffed microparticles. Although ordinary bamboo shoot powder has the same flavor, it does not have the porous elastic skeleton structure formed by humidification, granulation, pregelatinization and instantaneous puffing. It cannot be stably embedded in the interstitial spaces of the vascular bundles of bamboo shoots, nor can it effectively play the role of heat transfer node, pressure relief channel and pore center during frying. Therefore, the puffing degree and sensory score of the obtained product are significantly lower than those of Example 3.
[0105] III. Food Safety Indicator Testing In accordance with the relevant food safety standards for puffed foods, the puffed bamboo shoot products obtained in Example 3 were tested for food safety indicators, and the results are as follows: Table 3. Test results of food safety indicators for puffed bamboo shoot products in Example 3 As can be seen from Table 3, the puffed bamboo shoot products obtained in Example 3 have low moisture content, and the oil oxidation index and microbial index are all within a controllable range, which can meet the processing and storage requirements of snack ready-to-eat puffed foods.
[0106] Figure 4 In Example 3, a more reasonable moisture gradient is formed after temperature-controlled pre-drying, resulting in faster and more uniform release of free water during frying.
[0107] In summary, this invention, through a combined technical solution of "porous elastic puffed microparticles + embedded compounding + variable temperature pre-drying + frying puffing", can significantly improve the problems of collapse, hardening and uneven puffing caused by the dense structure during the frying puffing process of bamboo shoots, improve the puffing degree, crispness and pore uniformity of the product, and at the same time reduce color deterioration and oil adsorption. It has outstanding substantive features and significant progress.
Claims
1. An expanded microparticle, characterized in that, The puffed microparticles include a composite framework formed by edible starch, plant protein and dietary fiber. The composite framework is subjected to humidification, granulation, pregelatinization and instant puffing treatment to form microparticles with a porous structure and elastic support. The puffed microparticles are used to combine with bamboo shoot slices or shreds that have been color-protected, debittered, and flavored, and are dispersed on the surface and in the interstitial spaces of the bamboo shoot slices or shreds during the frying and puffing process to promote the formation of a uniform microporous structure in the bamboo shoot tissue.
2. The expanded microparticle according to claim 1, characterized in that, The expanded microparticles comprise the following components by weight: The ingredients are: 45-70 parts edible starch, 8-25 parts plant protein, 10-30 parts dietary fiber, 3-12 parts pregelatinized starch, 0.5-5 parts edible colloid, 2-10 parts bamboo shoot powder, and 18-35 parts water.
3. The expanded microparticle according to claim 2, characterized in that, The edible starch is one or more of corn starch, tapioca starch, potato starch, and rice starch; The plant protein is one or more of soy protein isolate, pea protein, wheat protein, and zein; The dietary fiber is one or more of the following: bamboo shoot dietary fiber, oat fiber, citrus fiber, resistant dextrin, and microcrystalline cellulose. The edible colloid is one or more of sodium carboxymethyl cellulose, xanthan gum, guar gum, sodium alginate, and low-ester pectin.
4. The expanded microparticle according to claim 1, characterized in that, The expanded microparticles have a D50 particle size of 80-600 μm, a D90 particle size of no more than 1000 μm, a moisture content of 4-10 wt%, and a bulk density of 0.18-0.55 g / cm³. 3 ; By controlling the D50 particle size and moisture content of the puffed microparticles, the puffed microparticles form a steam core in the early stage of frying and maintain structural strength during the frying and puffing process, thus delaying the complete gelatinization or collapse of the particles.
5. The expanded microparticle according to claim 4, characterized in that, The D50 particle size of the expanded microparticles is preferably 150-300 μm, the moisture content is preferably 5-8 wt%, and the bulk density is preferably 0.25-0.42 g / cm³. 3 .
6. The expanded microparticle according to claim 1, characterized in that, The porous structure includes open pores and closed pores with a pore size of 5-50 μm; The open hole forms a water vapor pressure release channel during the frying and puffing process, and the closed hole serves as the hole formation center; The puffed microparticles expand 1.5-3 times during the frying and puffing process, and form a counter-support with the volume contraction of the bamboo shoot tissue to maintain the puffed shape of the bamboo shoot slices or shreds.
7. A method for preparing expanded microparticles as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Mix edible starch, plant protein, dietary fiber, pregelatinized starch, edible colloids and bamboo shoot powder to obtain a dry powder mixture; Step 2: Add water to the dry powder mixture to adjust the moisture content of the material to 18-35 wt%, stir evenly, and then granulate to obtain wet microparticles; Step 3: Pregelatinize the wet microparticles to partially gelatinize the edible starch and form a complex framework with plant protein and dietary fiber to obtain pregelatinized microparticles. Step 4: The pregelatinized microparticles are subjected to instantaneous puffing treatment to form a porous structure inside, and then dried, cooled and sieved to obtain the puffed microparticles.
8. The method for preparing expanded microparticles according to claim 7, characterized in that, In step two, the granulation is carried out by twin-screw extrusion granulation, and the extrusion die temperature is 60-85℃; In step three, the pregelatinization treatment temperature is 75-105℃, and the treatment time is 3-20 min; In step four, the instantaneous puffing process is extrusion puffing, differential pressure instantaneous puffing, or hot air instantaneous puffing, with a puffing temperature of 120-190℃ and a puffing time of 5-90s. The drying temperature is 45-75℃, and after drying, the expanded microparticles with a particle size range of 80-800μm are retained by sieving, preferably with a particle size range of 150-500μm.
9. The application of the puffed microparticles according to any one of claims 1-6 in the preparation of puffed bamboo shoots, characterized in that, The puffed microparticles are combined with bamboo shoot slices or shreds that have been color-protected, debittered, and flavored. The puffed microparticles are dispersed and embedded in the surface and vascular bundle gaps of the bamboo shoot slices or shreds by stirring, tumbling, or vacuum adsorption, and then deep-fried and puffed. During the deep-frying and puffing process, the puffed microparticles serve as heat transfer nodes, water vapor depressurization channels, and pore-forming centers, promoting rapid migration of moisture inside the bamboo shoots and reducing the collapse, hardening, and uneven puffing phenomena caused by the dense fibrous tissue of the bamboo shoots.