Gradient gelatinization and preservation method for rice noodles

Abstract

The invention discloses a gradient gelatinization and preservation method for rice noodles, and belongs to the technical field of food processing. The preparation method comprises the following steps: mixing long-shaped rice flour, polished round-grained rice flour, wheat flour, corn starch, vital gluten and modified starch with water; then transferring into a double-screw extruder for extrusion forming, collecting the rice noodles, and standing for retrogradation; and performing gradient gelatinization on the rice noodles, spraying cold water for cooling, and finally drying to obtain the rice noodles. The rice noodles prepared by the process disclosed by the invention are smooth and elastic in mouth feel, low in breaking rate, excellent in rehydration property and storage property and suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a method for gradient gelatinization and preservation of rice noodles. Background Technology

[0002] Rice noodles are round or flat strips of rice made from rice as the main ingredient through a series of processes. Common types include Crossing-the-Bridge Rice Noodles, Rice Vermicelli, and Snail Rice Noodles. They are characterized by their smooth and elastic texture, rich rice aroma, and easy digestibility.

[0003] However, traditional rice noodle processing techniques have significant bottlenecks, severely hindering product quality improvement and high-quality industrial development. Firstly, rice noodles produced using traditional methods generally suffer from poor rehydration (easily developing a hard core or becoming excessively soft after rehydration), poor texture (lacking chewiness and elasticity), and a tendency to stick together and break, failing to meet consumers' demands for a smooth, chewy, and bouncy texture. Secondly, current processes passively and crudely control the starch gel structure, relying solely on high-temperature gelatinization and natural aging, resulting in unstable product quality and difficulty in achieving high-standard, large-scale production. Furthermore, wet rice noodles have high moisture and starch content, making them prone to spoilage; even under normal storage, they become sour and soften significantly within one or two days.

[0004] In view of this, in order to coordinate the requirements of rehydration, taste, stability and other aspects, developing a new production process for rice noodles with high overall quality is of great significance for high-end instant rice noodle brands to achieve a breakthrough. Summary of the Invention

[0005] To address the problems mentioned in the background art, this invention provides a method for gradient gelatinization and preservation of rice noodles. By targeted initial gelatinization and staged gradient gelatinization, while controlling parameters such as gradient and temperature in each interval, a balance is achieved in the rehydration, texture, and stability of the rice noodles. The resulting rice noodles have a smooth and chewy texture, low breakage rate, excellent rehydration and storage performance, and are suitable for industrial production.

[0006] To achieve the above objectives, the present invention specifically adopts the following technical solution: This invention provides a process for preparing rice noodles using gradient gelatinization, comprising the following steps: Step 1: Take indica rice flour, japonica rice flour, wheat flour, corn starch, gluten, and modified starch, add water and mix to obtain a mixture for later use; Step 2: Take the mixture and extrude it into shape using a twin-screw extruder. Collect the rice noodles and let them stand to reflux for later use. Step 3: The rice noodles obtained from the retrogradation process are subjected to gradient gelatinization, followed by spraying with cold water to cool them down, and finally drying to obtain the rice noodle product. The specific operation of gradient gelatinization is as follows: first, gelatinize at 52-60℃ and 95%-98% humidity for 10-20 min; then gelatinize at 70-75℃ and 93%-97% humidity for 1-1.5 h; and finally gelatinize at 64-68℃ and 90%-92% humidity for 0.6-1 h.

[0007] In one preferred embodiment, the rice noodle ingredients in step one include, by weight, 30-40 parts of indica rice flour, 10-15 parts of japonica rice flour, 5-8 parts of wheat flour, 6-10 parts of corn starch, 2-5 parts of gluten, 4-6 parts of modified starch, and 20-25 parts of water.

[0008] In a preferred embodiment, the modified starch is composed of acetate starch and octenyl succinate starch in a mass ratio of (2-5):1.

[0009] This invention first optimizes the raw materials of traditional rice noodle recipes: Indica rice flour has a high amylose content, forming the backbone of the rice noodles and determining their firmness, elasticity, and toughness; Japonica rice flour has a high amylopectin content, providing a soft, smooth texture and balancing the slightly firm texture of Indica rice, thus improving palatability. Too much of the former results in overly hard and easily broken noodles, while too much of the latter makes them too soft and unable to withstand cooking. This invention optimizes the ratio of the two, providing a foundation for high-quality rice noodles. Wheat flour forms a weak network structure during steaming and drying, which has a certain gluten-strengthening effect, increasing the strength of the rice noodles and reducing breakage; corn starch improves the transparency, gloss, and smoothness of the rice noodles; and gluten forms a protein network in the rice noodle system, intertwining with the starch network, further improving the toughness, elasticity, and strength of the rice noodles. In addition, the present invention also adds acetate starch and octenyl succinate starch: acetate starch acts as an internal structure enhancer to build a more stable and tougher gel network, significantly improving elasticity and toughness, and improving anti-aging and cooking resistance; octenyl succinate starch acts as a texture regulator to optimize the interaction between amyl / branched starch and protein, making the rice noodles more uniform and delicate, and improving smoothness and chewiness.

[0010] In a preferred embodiment, the extrusion parameters of the twin-screw extruder in step two are: screw speed 150-200 rpm; extrusion temperature set at 80-90℃; and outlet temperature set at 50-55℃. This invention first uses a twin-screw extruder to extrude the mixture into rice noodles. The frictional heat and shear force during extrusion cause some starch to undergo pregelatinization, which directly affects the appearance and initial texture of the rice noodles. Proper pregelatinization is also crucial for preparing high-quality rice noodles.

[0011] As a preferred embodiment, the settling and regeneration process in step two employs low-temperature treatment, specifically settling at 8-12℃ and 97%-99% humidity for 3-6 hours. Traditional processes involve aging and regeneration at room temperature or slightly above room temperature. As a crucial step determining the chewiness of rice noodles, insufficient aging and regeneration results in soft, mushy noodles lacking chewiness, while excessive aging leads to overly hard noodles with poor rehydration properties. This invention utilizes lower temperature and higher humidity conditions for aging and regeneration, significantly shortening the processing time and ensuring stable product quality, thus avoiding problems caused by improper aging control.

[0012] As a preferred embodiment, before spraying cold water to cool down after the gradient gelatinization in step three, the vacuum is further drawn to -0.05~-0.02 MPa and kept warm for 5-10 min.

[0013] As one of the most crucial steps in rice noodle processing, the gelatinization process directly affects the texture and stability of the noodles. This invention employs gradient gelatinization, which focuses on not achieving complete, one-time gelatinization of starch, but rather applying energy in stages and with control to obtain more ideal product texture, stability, and processing characteristics. This invention rationally adjusts the temperature and humidity at each gradient for segmented gelatinization, allowing the rice noodles to gelatinize slowly and uniformly under preset temperature and humidity conditions. This ensures consistent maturity throughout the noodles, while simultaneously enabling starch molecules to form an ordered network structure, thereby improving the chewy texture and toughness, and significantly reducing the breakage rate. A brief vacuum insulation treatment after gelatinization further homogenizes the internal structure of the rice noodles, allowing starch molecular chains more opportunities for rearrangement and interaction, resulting in exceptional chewiness and elasticity.

[0014] As a preferred embodiment, the drying in step three is carried out by hot air drying: the first stage temperature is controlled at 60-70℃ for 45-60 min; the second stage temperature is controlled at 80-85℃ for 50-70 min; the third stage temperature is controlled at 40-55℃ for 50-70 min; and the fourth stage temperature is controlled at 20-25℃ for 30-40 min.

[0015] In a preferred embodiment, the air velocity for hot air drying is 1.2-2.0 m / s; when the hot air drying reaches the third stage, microwave treatment is also required, with a microwave power of 200-300 W / m. 2 .

[0016] For the final drying process, this invention employs gradient hot air / microwave drying: a medium temperature is used as the initial drying environment to remove most of the surface and internal moisture; the second stage uses high temperature to further remove deep-seated bound water; and the third stage gradually and slowly cools down while introducing microwaves to heat the interior, accelerating the diffusion of internal moisture outwards to achieve moisture balance. By precisely controlling the temperature of each stage of the drying process, the rehydration properties and quality of the resulting rice noodles are significantly improved.

[0017] This invention also provides a method for rehydrating and preserving rice noodles prepared using the above-mentioned gradient gelatinization process, comprising: Rehydrate the rice noodles, then soak them in the treatment solution to sterilize and seal them in packaging. The treatment solution is prepared by mixing water, sodium tripolyphosphate, maltodextrin, and ethanol in a mass ratio of 100:(1.5-3):(8-12):(0.2-0.5).

[0018] The beneficial effects of this invention are: This invention overcomes the shortcomings of traditional rice noodle production processes, producing rice noodles that are chewy, smooth, elastic, uniform, and delicate, with a low breakage rate and excellent rehydration properties. The overall process is simple to operate and easy to control, resulting in good batch stability and a significantly extended shelf life, giving it a strong competitive edge in the market. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with embodiments. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] Example 1 A process for preparing rice noodles using gradient gelatinization, comprising the following steps: 1. Weigh out 35 parts of indica rice flour, 12 parts of japonica rice flour, 6 parts of wheat flour, 8 parts of corn starch, 4 parts of gluten, 5 parts of modified starch (a mixture of acetate starch and octenyl succinic acid starch in a mass ratio of 3:1), and 24 parts of water according to the following weight proportions: Add water to the above powders and mix to obtain a mixture for later use.

[0022] 2. Transfer the mixture into a twin-screw extruder and set the parameters: screw speed 180 rpm; extrusion temperature 85℃; discharge port temperature 52℃. Extrude to form rice noodles. Transfer the obtained rice noodles into an aging chamber and let them stand for 4.5 hours at 10℃ and 98% humidity for later use.

[0023] 3. Gradient gelatinization of the rice noodles obtained from the settling process: First, gelatinize at 55℃ and 96% humidity for 15 min; then at 72℃ and 95% humidity for 1.2 h; finally, gelatinize at 65℃ and 91% humidity for 0.8 h. After gradient gelatinization, vacuum to -0.03 MPa and continue to maintain the temperature for 8 min; then remove and spray with cold water. Finally, transfer to a drying chamber for gradient hot air drying (wind speed 1.6 m / s): the first stage temperature is controlled at 65℃ for 50 min; the second stage temperature is controlled at 83℃ for 60 min; the third stage temperature is controlled at 50℃ for 60 min (microwave treatment is used during the process, with a power of 240 W / m). 2 (The temperature is controlled at four levels, 22℃, for 35 minutes. Cut and package to obtain the rice noodle product.)

[0024] Example 2 A process for preparing rice noodles using gradient gelatinization, comprising the following steps: 1. Weigh out 30 parts of indica rice flour, 10 parts of japonica rice flour, 5 parts of wheat flour, 6 parts of corn starch, 2 parts of wheat gluten, 4 parts of modified starch (a mixture of acetate starch and octenyl succinic acid starch in a mass ratio of 2:1), and 20 parts of water according to the following weight proportions: Add water to the above powders and mix to obtain a mixture for later use.

[0025] 2. Transfer the mixture into a twin-screw extruder and set the parameters: screw speed 150 rpm; extrusion temperature 80℃; discharge port temperature 50℃. Extrude to form rice noodles. Transfer the obtained rice noodles into an aging chamber and let them stand for 3 hours at 8℃ and 97% humidity for later use.

[0026] 3. Gradient gelatinization of the rice noodles obtained from the settling process: First, gelatinize at 52℃ and 95% humidity for 20 min; then gelatinize at 70℃ and 93% humidity for 1.5 h; finally, gelatinize at 64℃ and 90% humidity for 1 h. After gradient gelatinization, vacuum to -0.05 MPa and continue to maintain the temperature for 5 min; then remove and spray with cold water. Finally, transfer to a drying chamber for gradient hot air drying (wind speed 1.6 m / s): the first stage temperature is controlled at 60℃ for 60 min; the second stage temperature is controlled at 80℃ for 70 min; the third stage temperature is controlled at 40℃ for 70 min (microwave treatment is used during the process, with a power of 240 W / m). 2 (The temperature is controlled at four levels, each at 20℃ for 40 minutes. Cut and package to obtain the rice noodle product.)

[0027] Example 3 A process for preparing rice noodles using gradient gelatinization, comprising the following steps: 1. Weigh out 40 parts of indica rice flour, 15 parts of japonica rice flour, 8 parts of wheat flour, 10 parts of corn starch, 5 parts of wheat gluten, 6 parts of modified starch (a mixture of acetate starch and octenyl succinic acid starch in a mass ratio of 5:1) and 25 parts of water according to the following weight proportions: Add water to the above powders and mix to obtain a mixture for later use.

[0028] 2. Transfer the mixture into a twin-screw extruder and set the parameters: screw speed 200 rpm; extrusion temperature 90℃; discharge port temperature 55℃. Extrude to form rice noodles. Transfer the obtained rice noodles into an aging chamber and let them stand for 6 hours at 12℃ and 99% humidity for later use.

[0029] 3. Gradient gelatinization of the rice noodles obtained from the settling process: First, gelatinize at 60℃ and 98% humidity for 10 min; then gelatinize at 75℃ and 97% humidity for 1 h; finally, gelatinize at 68℃ and 92% humidity for 0.6 h. After gradient gelatinization, vacuum to -0.02 MPa and continue to maintain the temperature for 10 min; then remove and spray with cold water. Finally, transfer to a drying chamber for gradient hot air drying (wind speed 1.6 m / s): the first stage temperature is controlled at 70℃ for 45 min; the second stage temperature is controlled at 85℃ for 50 min; the third stage temperature is controlled at 55℃ for 50 min (microwave treatment is used during the process, with a power of 240 W / m). 2 (The temperature is controlled at four levels, each at 25℃ for 30 minutes. After cutting and packaging, the rice noodle product is obtained.)

[0030] Comparative Example 1 The steps and parameters are the same as in Example 1 of this invention, except that octenyl succinic acid starch is not added to the rice noodle raw materials.

[0031] Comparative Example 2 The steps and parameters are the same as in Example 1 of this invention, except that the regeneration aging parameters are adjusted to: stand at 30°C for 18 h.

[0032] Comparative Example 3 The steps and parameters are the same as in Example 1 of this invention, except that the gradient gelatinization is adjusted to gelatinize at 65°C and 95% humidity for 2.5 h.

[0033] Comparative Example 4 The steps and parameters are the same as in Embodiment 1 of this invention, except that vacuum insulation is not performed after gradient gelatinization.

[0034] Comparative Example 5 The steps and parameters are the same as in Embodiment 1 of the present invention, except that the gradient hot air drying process is not supplemented by microwave treatment.

[0035] Test case The rice noodle samples prepared in the above embodiments and comparative examples were tested, and the results are shown in Table 1 (the testing standards are based on SN / T 0395 Rice Noodle Inspection Procedure).

[0036] Table 1. Test results of rice noodle samples

[0037] The rice noodles prepared in the above examples and comparative examples were rehydrated and then immersed in a treatment solution (prepared by mixing water, sodium tripolyphosphate, maltodextrin, and ethanol in a mass ratio of 100:2:10:0.4) for 3 minutes, followed by sterilization (80℃, 10 minutes), and vacuum-sealed packaging to obtain the wet rice noodle products. After being stored at room temperature for a period of time, their preservation effect was tested, and the results are shown in Table 2 (testing was conducted according to GB 4789).

[0038] Table 2 Results of rice noodle storage and preservation

[0039] In summary, the rice noodles prepared by the process of this invention are elastic, have a good taste, low breakage rate, and excellent rehydration performance. Adjusting the raw material system and aging / gelatinization process parameters both reduce the quality of the rice noodles to varying degrees. This invention produces high-quality rice noodles that are chewy, smooth, elastic, uniform, and delicate, with low breakage rate and excellent rehydration performance. The product exhibits good batch stability, a significantly extended shelf life, and strong market competitiveness.

[0040] The embodiments described above are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they are not intended to limit the present invention. It should be noted that various changes and modifications can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the concept and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process for preparing rice noodles with gradient gelatinization, characterized in that, Includes the following steps: Step 1: Take indica rice flour, japonica rice flour, wheat flour, corn starch, gluten, and modified starch, add water and mix to obtain a mixture for later use; Step 2: Take the mixture and extrude it into shape using a twin-screw extruder. Collect the rice noodles and let them stand to reflux for later use. Step 3: The rice noodles obtained from the retrogradation process are subjected to gradient gelatinization, followed by spraying with cold water to cool them down, and finally drying to obtain the rice noodle product. The specific operation of gradient gelatinization is as follows: first, gelatinize at 52-60℃ and 95%-98% humidity for 10-20 min; then gelatinize at 70-75℃ and 93%-97% humidity for 1-1.5 h; and finally gelatinize at 64-68℃ and 90%-92% humidity for 0.6-1 h.

2. The preparation process of rice noodles with gradient gelatinization according to claim 1, characterized in that, The ingredients for rice noodles in step one, by weight, include: 30-40 parts of indica rice flour, 10-15 parts of japonica rice flour, 5-8 parts of wheat flour, 6-10 parts of corn starch, 2-5 parts of wheat gluten, 4-6 parts of modified starch, and 20-25 parts of water.

3. The preparation process of rice noodles with gradient gelatinization according to claim 2, characterized in that, The modified starch is composed of acetate starch and octenyl succinate starch in a mass ratio of (2-5):

1.

4. The preparation process of rice noodles with gradient gelatinization according to claim 1, characterized in that, In step two, the extrusion molding parameters for the twin-screw extruder are: screw speed 150-200 rpm; extrusion temperature set at 80-90℃; and discharge port temperature set at 50-55℃.

5. The preparation process of rice noodles with gradient gelatinization according to claim 1, characterized in that, Step two involves a low-temperature treatment for the regeneration process, specifically a 3-6 hour resting period at 8-12°C and 97%-99% humidity.

6. The preparation process of rice noodles with gradient gelatinization according to claim 1, characterized in that, Before spraying cold water to cool down after the gradient gelatinization described in step three, the process also includes evacuating to -0.05~-0.02 MPa and continuing to keep warm for 5-10 minutes.

7. The preparation process of rice noodles with gradient gelatinization according to claim 1, characterized in that, The drying process described in step three uses hot air drying: the first stage temperature is controlled at 60-70℃ for 45-60 min; the second stage temperature is controlled at 80-85℃ for 50-70 min; the third stage temperature is controlled at 40-55℃ for 50-70 min; and the fourth stage temperature is controlled at 20-25℃ for 30-40 min.

8. The preparation process of rice noodles with gradient gelatinization according to claim 7, characterized in that, The air velocity for hot air drying is 1.2-2.0 m / s; when the hot air drying reaches the third stage, it is also necessary to supplement it with microwave treatment, with a microwave power of 200-300 W / m. 2 .

9. A method for rehydrating and preserving rice noodles prepared using the gradient gelatinization process according to any one of claims 1-8, characterized in that, include: Rehydrate the rice noodles, then soak them in the treatment solution to sterilize and seal them in packaging. The treatment solution is prepared by mixing water, sodium tripolyphosphate, maltodextrin, and ethanol in a mass ratio of 100:(1.5-3):(8-12):(0.2-0.5).

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