Vermicelli with microporous structure and self-nucleation preparation method thereof

Abstract

The invention discloses vermicelli with a microporous structure and a self-nucleation preparation method of the vermicelli, and belongs to the technical field of food production.The vermicelli is prepared from starch powder, edible gum, cellulose micron particles homologous with the starch powder and water. Homologous cellulose micron particles are used as a nucleating agent for self-nucleation regulation and control of a vermicelli micropore structure, and vermicelli food with the micropore structure is prepared in one step. According to the method, the rehydration performance of the vermicelli can be improved on the basis of ensuring the original food characteristics of the vermicelli.

Description

Technical Field

[0001] The present invention belongs to the technical field of food production, and particularly relates to vermicelli with a microporous structure and a self-nucleation preparation method thereof. Background Art

[0002] Traditional Chinese foods, such as various starch vermicelli-based foods like snail rice noodles, Guilin rice noodles, cross-bridge rice noodles, etc., face the demand for instant food promotion in today's fast-paced life. However, vermicelli produced by traditional processes such as "extrusion / strainer - drying" have many drawbacks. Their production process is complex and discontinuous, making it difficult to achieve large-scale industrial promotion. Moreover, the matrix structure of the vermicelli is dense, resulting in longer rehydration and cooking times, unable to meet consumers' requirements for the convenience of instant foods.

[0003] Currently, for low-moisture starch gel foods such as vermicelli, in order to improve their rehydration properties, many studies have focused on constructing a porous structure of the starch gel. A perfect porous structure can weaken the density of the matrix, increase the contact area with water, and at the same time reduce the water penetration path, thus significantly shortening the rehydration time. For example, a porous structure is constructed by dehydrating through different drying processes (such as freezing, microwave, and hot air, etc.); or substances such as maltodextrin and amylase are added, and a porous structure is formed by dissolving or enzymatically degrading starch; or an extrusion puffing method can be used to construct the porous structure of starch gel foods. However, unfortunately, despite these various attempts, they are not suitable for improving the rehydration properties of vermicelli. Moreover, these solutions also have a series of deficiencies in actual production: First, the porous structure constructed by the methods of dissolution or drying to leave pores is not perfect, it is difficult to significantly improve the rehydration performance, and it is impossible to "actively" target and design the porous structure; Second, drying easily causes the vermicelli matrix to shrink, with extremely low production efficiency and accompanied by huge energy consumption; Third, the dissolution and enzymatic degradation operations of maltodextrin, amylase, etc. will affect the original flavor of the food; Fourth, the pore structure expands excessively during the current extrusion puffing process, causing the vermicelli to lose its original food characteristics.

[0004] Therefore, it is particularly crucial to explore a preparation method that can actively regulate and design the microporous structure of the vermicelli matrix. By precisely controlling parameters such as the uniformity, pore size, and porosity of the microporous structure, on the basis of ensuring that the vermicelli maintains its original food quality, its rehydration properties can be significantly improved, thus effectively promoting the instant food process of vermicelli. Summary of the Invention

[0005] The present invention provides a kind of vermicelli with microporous structure and its self-nucleating preparation method. The present invention constructs a starch melt processing system by using a twin-screw extruder, and uses homologous cellulose micron particles as nucleating agents to self-nucleate and regulate the microporous structure of vermicelli, and prepares a vermicelli food with microporous structure in one step. The method of the present invention can improve the rehydration performance of vermicelli while ensuring its original food properties.

[0006] Technical solution: A kind of vermicelli with microporous structure is prepared from the following raw materials:

[0007] Starch powder: 59% - 88.9 wt%;

[0008] Edible glue: 1 - 10 wt%;

[0009] Cellulose micron particles homologous to the starch powder: 0.1 - 1 wt%;

[0010] Water: 10 - 30 wt%;

[0011] The sum of the mass percentages of the starch powder, edible glue, cellulose micron particles, and water is 100 wt%.

[0012] Furthermore, the starch powder is one of traditional vermicelli raw materials such as rice starch, cassava starch, corn starch, potato starch, sweet potato starch, etc.

[0013] Furthermore, the edible glue is one or several of edible glues such as gelatin, carrageenan, xanthan gum, sodium alginate, etc., and the edible glue is used to regulate the melting strength of starch during gelatinization.

[0014] The cellulose micron particles are homologous to the starch selected for the starch powder; the cellulose micron particles are micron-sized cellulose particles obtained by fully drying, pulverizing, and modifying rice husk fiber, cassava fiber, corn husk fiber, potato fiber, sweet potato fiber, etc. The particle size of the cellulose micron particles is less than 100 um.

[0015] The modification method is: first fully dry the corresponding cellulose (85 - 100 °C, 24 h), and then use a high-speed rotating ball mill tank and spheres to grind the cellulose to obtain micron-sized cellulose particles.

[0016] A self-nucleating production preparation method of a kind of vermicelli with microporous structure includes the following steps:

[0017] Step 1, place starch, edible glue, cellulose micron particles, and water in a high-speed mixer according to the corresponding proportions, and initially blend them at a speed of 100 - 2000 rpm to form a preliminary blend.

[0018] Step 3: Continuously add the preliminary mixture into a twin-screw extruder through a feeder, and subject the preliminary mixture to processes such as blending, pasting / plasticizing, extrusion micro-expansion, and collection in the twin-screw extruder in sequence to prepare vermicelli with a microporous structure. The blending and pasting / plasticizing processes are completed in the machine cavity of the twin-screw extruder, and the extrusion micro-expansion process is completed at the die head.

[0019] Further, in Step 2, the twin-screw extruder includes a machine cavity and a die head. The machine cavity is divided into Zone 1 - Zone 7 in the feeding-to-discharging direction of the twin-screw. Set the temperature ranges of Zone 1 - Zone 7 and the die head to be 40 - 180 °C (when the moisture content is high, set a lower temperature; when the moisture content is low, set a higher temperature to ensure sufficient plasticization of starch, that is, the closer to the discharging direction of the twin-screw, the higher the temperature), and the screw speed is 100 - 1000 rpm.

[0020] Further, in Step 2, the temperatures of Zone 1 - Zone 7 and the die head are specifically set as follows:

[0021] Zone 1 is 40 °C, Zone 2 is 80 °C - 90 °C, Zone 3 is 120 °C - 130 °C, Zone 4 is 135 °C - 180 °C, Zone 5 is 135 °C - 180 °C, Zone 6 is 135 °C - 180 °C, Zone 7 is 135 °C - 180 °C, and the die head is 135 °C - 180 °C.

[0022] In the pasting / plasticizing process, by adjusting the temperatures of the extruder machine cavity and the die head, while the starch is plasticized, the internal moisture is in a superheated state / subcritical state.

[0023] In the extrusion micro-expansion process, the plasticized starch melt is extruded under high pressure from the die head. The superheated water inside the starch melt releases pressure and evaporates at the moment it comes out of the die head, so that a void structure can be formed inside the starch melt. And because the moisture content inside the starch melt is relatively low, at the moment it leaves the die head of the extruder, as the water vapor evaporates, the starch melt immediately solidifies, thus fixing the microporous structure formed by the departure of the water vapor.

[0024] The collection process refers to collecting the already formed vermicelli extruded from the die head. Since the moisture content inside the original material is relatively low and the water vapor further evaporates during the establishment of the pore structure, finally the moisture content of the vermicelli extruded from the die head is relatively low, and it can meet the product requirements without further drying, realizing one-step continuous production of vermicelli.

[0025] Beneficial effects:

[0026] 1) In the present invention, the raw material cellulose micro-particles have relatively high hardness and relatively high thermal stability. During the thermoplastic processing in the extruder, they can maintain their own properties without being damaged and play the role of a nucleating agent here. The cellulose micro-particles and the starch powder use the same source of starch, and can achieve self-nucleating function to regulate the formation of the microporous structure.

[0027] 2) In the raw materials of the present invention, the water content is relatively low. Combining with a specifically designed starch extrusion process, low-moisture gelatinization / plasticization molding of starch is achieved.

[0028] 3) In the paste / plasticization process, the water content of the material entering the extruder is much lower than the water content for normal starch gelatinization. By adjusting the temperatures of the extruder barrel and die head, while the starch is plasticized, the internal water is in a superheated state / subcritical state. Detailed implementation manners

[0029] The technical solution of the present invention will be described in detail below through embodiments, but the protection scope of the present invention is not limited to the described embodiments.

[0030] The raw materials in the following embodiments can all be purchased from the market, and the particle size of the cellulose micro-particles used is less than 100 μm.

[0031] Embodiment 1

[0032] This embodiment provides a vermicelli with a microporous structure, which is prepared from the following components:

[0033] Rice starch powder: 59 wt%, edible gum (carrageenan): 10 wt%, cellulose micro-particles homologous to rice: 1 wt%, water: 30 wt%.

[0034] The cellulose micro-particles homologous to rice are cellulose micro-particles modified from rice husk fibers.

[0035] A preparation method of vermicelli with a microporous structure includes the following steps:

[0036] 1) Place rice starch, carrageenan, water, and cellulose micro-particles in a high-speed mixer according to the above proportions, and initially blend them at a speed of about 1000 rpm for 1 minute to form a preliminary blend.

[0037] 2) Add the preliminary blend to a twin-screw extruder at a feeding speed of 25 rpm. The temperatures of each zone of the extruder are respectively: zone 1: 40 °C, zone 2: 80 °C, zone 3: 120 °C, zone 4: 135 °C, zone 5: 135 °C, zone 6: 135 °C, zone 7: 135 °C, die head: 135 °C. The screw speed is 150 rpm, and the aperture of the die head outlet is 3 mm to produce vermicelli food. The average pore diameter, pore size uniformity, porosity, rehydration time, and taste of the microporous structure inside the vermicelli are shown in Table 1.

[0038] Embodiment 2

[0039] This embodiment provides a vermicelli with a microporous structure, which is prepared from the following components:

[0040] Cassava starch powder: 75 wt%, Edible gum (carrageenan): 5 wt%, Homologous cellulose micro-particles: 0.5 wt%, Water: 19.5 wt%.

[0041] The homologous cellulose micro-particles are cellulose micro-particles (below 100um) obtained by modifying cassava fiber.

[0042] A method for preparing vermicelli with a microporous structure, comprising the following steps:

[0043] 1) Place cassava starch, carrageenan, water, and cellulose micro-particles in a high-speed mixer according to the ratio, and initially blend them at a speed of 500 rpm for 2 min to form a preliminary blend;

[0044] 2) Add the preliminary blend to a twin-screw extruder at a feeding speed of 25 rpm. The temperatures of each zone of the extruder are: Zone 1: 40°C, Zone 2: 80°C, Zone 3: 120°C, Zone 4: 150°C, Zone 5: 150°C, Zone 6: 150°C, Zone 7: 150°C, Die: 150°C. The screw speed is 150 rpm, and the aperture of the die outlet is 3 mm to produce vermicelli food. The average pore diameter, pore size uniformity, porosity, rehydration time, and taste of the microporous structure inside the vermicelli are listed in Table 1.

[0045] Example 3

[0046] This example provides a kind of vermicelli with a microporous structure, which is prepared from the following components: Sweet potato starch powder: 88.9 wt%, Edible gum (sodium alginate): 1 wt%, Homologous cellulose micro-particles: 0.1 wt%, Water: 10 wt%.

[0047] The homologous cellulose micro-particles are cellulose micro-particles obtained by modifying sweet potato fiber.

[0048] A method for preparing vermicelli with a microporous structure, comprising the following steps:

[0049] 1) Place sweet potato starch, carrageenan, water, and cellulose micro-particles in a high-speed mixer according to the corresponding ratio, and initially blend them at a speed of 200 rpm for 3 min to form a preliminary blend;

[0050] 2) Add the preliminary blend to a twin-screw extruder at a feeding speed of 25 rpm. The temperatures of each zone of the extruder are: Zone 1: 40°C, Zone 2: 90°C, Zone 3: 130°C, Zone 4: 180°C, Zone 5: 180°C, Zone 6: 180°C, Zone 7: 180°C, Die: 180°C. The screw speed is 150 rpm, and the aperture of the die outlet is 3 mm to produce vermicelli food. The average pore diameter, pore size uniformity, porosity, rehydration time, and taste of the microporous structure inside the vermicelli are listed in Table 1.

[0051] Comparative Example 1

[0052] This comparative example provides vermicelli with a microporous structure prepared using microcrystalline starch, which is prepared from the following components: cassava starch powder: 75 wt%, edible gum (carrageenan): 5 wt%, microcrystalline starch: 0.5 wt%, water: 19.5 wt%.

[0053] The microcrystalline starch is obtained by modifying cassava starch (the particle size after modification is below 100 um), and has good thermal stability, so as to play the role of a nucleating agent here.

[0054] The preparation method of the vermicelli with a microporous structure includes the following steps:

[0055] 1) Place cassava starch, carrageenan, water, and microcrystalline starch in a high-speed mixer according to the corresponding proportions, and initially blend them at a speed of 500 rpm for 2 minutes to form a preliminary blend.

[0056] 2) Add the preliminary blend to a twin-screw extruder at a feeding speed of 25 rpm. The temperatures of each zone of the extruder are: zone 1: 40 °C, zone 2: 80 °C, zone 3: 120 °C, zone 4: 150 °C, zone 5: 150 °C, zone 6: 150 °C, zone 7: 150 °C, die head: 150 °C. The screw speed is 150 rpm, and the aperture of the die head outlet is 3 mm to produce vermicelli food. The average pore diameter, pore size uniformity, porosity, rehydration time, and taste of the microporous structure inside the vermicelli are listed in Table 1.

[0057] Comparative Example 2

[0058] This comparative example provides vermicelli with a microporous structure prepared from non-homologous cellulose micro-particles, which is prepared from the following components: cassava starch powder 75 wt%, edible gum (carrageenan) 05 wt%, non-homologous cellulose micro-particles 0.5 wt%, water 19.5 wt%.

[0059] The non-homologous cellulose micro-particles are obtained by fully drying, crushing, and modifying corn husk fibers, and have high hardness and high thermal stability, and play the role of a nucleating agent here.

[0060] The preparation method of the vermicelli with a microporous structure includes the following steps:

[0061] 1) Place cassava starch, carrageenan, water, and non-homologous cellulose micro-particles in a high-speed mixer according to the corresponding proportions, and initially blend them at a speed of 500 rpm for 2 minutes to form a preliminary blend.

[0062] 2) The premix was added to a twin-screw extruder at a feeding speed of 25 rpm. The temperatures of each zone of the extruder were as follows: Zone 1: 40°C, Zone 2: 80°C, Zone 3: 120°C, Zone 4: 150°C, Zone 5: 150°C, Zone 6: 150°C, Zone 7: 150°C, and the die head: 150°C. The screw speed was 150 rpm, and the aperture of the die head outlet was 3 mm, producing vermicelli food. The average pore diameter, pore size uniformity, porosity, rehydration time, and taste of the internal microporous structure of the vermicelli were listed in Table 1.

[0063] Table 1: Microporous parameters and rehydration time of vermicelli

[0064]

[0065] Note:

[0066] 1. The average pore diameter and porosity of the vermicelli were calculated by taking cross-sectional pictures of the vermicelli through a scanning electron microscope and then analyzing the data.

[0067] 2. Test method for rehydration time: The vermicelli was placed in a water bath at 95°C and left still, clamped with two glass slides, and the gelatinization state of the vermicelli was observed. When there was no obvious hard core, the rehydration was completed.

[0068] 3. In Comparative Example 1, microcrystalline starch was used as a nucleating agent. After research and analysis, it was found that the microcrystalline starch was damaged during the high-temperature processing and failed to play the role of a nucleating agent.

[0069] 4. In Comparative Example 2, non-homologous cellulose micro-particles had an impact on the taste and food odor of the vermicelli after high-temperature processing, showing differences from the original vermicelli.

[0070] 5. In Table 1, the original vermicelli was prepared by the traditional ladle method using starch and water (the ratio of starch to water was approximately 1:5 - 1:7) in the corresponding examples and comparative examples. Specifically, the starch was mixed with water to form a starch milk, which was placed in a ladle with holes and leaked into boiling water to be cooked, and then fished out and dried into shape.

[0071] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as a limitation of the present invention itself. Various changes can be made in its form and details without departing from the spirit and scope of the present invention.

Claims

1. A vermicelli with a microporous structure, characterized in that: The vermicelli is prepared from the following raw materials: Starch powder: 59% to 88.9wt%; Edible gum: 1-10wt%; Cellulose micronized particles homologous to the starch powder: 0.1-1 wt%; Water: 10-30wt%; The sum of the mass percentages of the starch powder, edible gum, cellulose micron particles and water is 100wt%.

2. The vermicelli according to claim 1, characterized in that: The starch powder is one of rice starch, tapioca starch, corn starch, potato starch and sweet potato starch.

3. The vermicelli according to claim 1, characterized in that: The edible gum is one or more of gelatin, carrageenan, xanthan gum and sodium alginate.

4. The vermicelli according to claim 1, characterized in that: The cellulose micron particles are one of rice husk fiber, cassava fiber, corn husk fiber, potato fiber and sweet potato fiber, and the particle size of the cellulose micron particles is less than 100 um.

5. The self-nucleating preparation method of vermicelli according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: Place starch, edible gum, cellulose micron particles and water in a high-speed mixer for preliminary blending to form a primary mixture; Step 2: continuously add the primary mixture into a twin-screw extruder through a feeder, so that the primary mixture is subjected to the steps of blending, pasting / plasticizing, and extrusion micro-expansion in the twin-screw extruder in sequence to prepare vermicelli with a microporous structure.

6. The self-nucleating preparation method according to claim 5, characterized in that: In step 2, the twin-screw extruder includes a machine cavity and a die head, the blending and paste / plasticization process is completed in the machine cavity of the twin-screw extruder, and the extrusion micro-expansion process is completed at the die head; The machine cavity is divided into zone 1 to zone 7 according to the feeding to discharging direction of the twin screw, and the temperature range of zone 1 to zone 7 and the die head is set to 40-180°C, and the screw speed is set to 100-1000rpm.

7. The self-nucleating preparation method according to claim 6, characterized in that: In step 2, the temperature of zones 1 to 7 and the die head are specifically set as follows: The temperature of zone one is 40℃, zone two is 80℃-90℃, zone three is 120℃-130℃, zone four is 135℃-180℃, zone five is 135℃-180℃, zone six is ​​135℃-180℃, zone seven is 135℃-180℃, and the die head is 135℃-180℃.

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