Novel Mongolian fragrant rice processing technology suitable for plateau areas

Abstract

The invention discloses a novel Mongolian fragrant rice processing technology suitable for a plateau area, and relates to the technical field of food processing, continuous operation is realized through the technologies of soaking rice in warm water, repeatedly washing the rice for three times, grinding into thick liquid, steaming pieces, extruding shreds, re-steaming, cooling in cold water, bagging or framing and the like; the prepared rice noodles are high in gelatinization degree, good in muscles and bones and good in smoothness, and can be stored at normal temperature for 24 hours; plateau boiling point limitation is broken through double-stage temperature control, curing is uniform, forming is stable, and the problems of insufficient secondary processing curing and broken strip adhesion of a traditional technology are solved.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a novel Mengzi fragrant rice processing technology suitable for plateau areas. Background Art

[0002] In plateau regions like Yunnan, the processing of Physalis rice noodles, a traditional specialty food, has long faced three technical bottlenecks: efficiency, quality, and environmental adaptability. Specific manifestations are as follows: 1. The process is complicated and the production cycle is long The traditional production process for Physalis rice noodles involves over nine steps: soaking the rice in boiling water for 24 hours, grinding the rice, bagging and dehydrating it, naturally fermenting it for 24-36 hours, then beating it into powder, steaming it, extruding it into strands, boiling it in boiling water, and finally cooling it in cold water. The natural fermentation process alone accounts for over 50% of the total labor time. This process relies on ambient temperature (e.g., room temperature of 20-25°C) and the natural growth of microorganisms. This process is susceptible to seasonal and humidity changes, resulting in unstable fermentation levels and requiring frequent manual adjustments, making it difficult to achieve industrial mass production.

[0003] 2. Product quality relies on experience and has poor stability Insufficient ripening and molding defects: The traditional process uses a "semi-cooking + secondary processing" model—first, the rice slurry is processed to a semi-cooked state, and then cooked in boiling water for secondary cooking. However, in areas such as Yunnan, at an altitude of 1,890 meters, the boiling point of water is only 93.7°C, lower than the 100°C at standard atmospheric pressure. This results in incomplete cooking of the center of the rice noodles during the secondary cooking, leading to breakage and sticking. Prolonging the cooking time also leads to excessive gelatinization of the outer layer, losing its texture.

[0004] Taste and transportation limitations: Traditional rice noodles become sour and soften after only one day of storage at room temperature. The reasons include: ① The organic acids produced by natural fermentation are not effectively controlled, which accelerates starch aging; ② Secondary processing causes a high rate of surface damage to the rice noodles, making it easy for microorganisms to invade; ③ The noodles lack a strong texture (tensile strength is often less than 100g / cm²), making them prone to breakage during transportation.

[0005] 3. Insufficient adaptability to the plateau environment and lack of targeted technical solutions Existing processes have not systematically studied the effects of plateau low pressure on starch gelatinization. For example: Steaming temperature mismatch: Traditional steaming uses the temperature parameters of plain areas (e.g., 100°C), but the actual steam temperature in the plateau is only around 93°C, resulting in insufficient gelatinization of the rice slurry and prone to "tailing" and "breakage" during extrusion. Energy waste: In order to compensate for the lower boiling point, some manufacturers blindly extend the steaming time, but this will cause the surface of the rice slurry to carbonize, while the inside is still not cooked, resulting in a "half-cooked" phenomenon.

[0006] Therefore, how to break through the limitation of the boiling point at high altitudes, achieve one-time and efficient forming of rice noodle processing through process reconstruction, and improve the product quality stability at the same time has become the research focus of those skilled in the art. Summary of the Invention

[0007] The purpose of the present invention is to provide a new processing technology for Mengzi fragrant rice noodles with one-time forming, strong adaptability to high-altitude environments, and stable product quality, so as to solve the problems of long fermentation time, cumbersome secondary processing, and poor noodle quality in the prior art.

[0008] The present invention solves the above technical problems through the following technical solutions: A new processing technology for Mengzi fragrant rice applicable to high-altitude areas includes the following steps: S1: Soak the rice in warm water at 30-50°C for 36-48 hours until the rice grains are fully swollen by absorbing water and can be crushed without a hard core; S2: Wash the soaked rice at least 3 times repeatedly to remove surface impurities and free starch; S3: Grind the washed rice into delicate rice milk with a particle size of 80-100 meshes; S4: Spread the rice milk into a rice milk layer with a thickness of 2-3 cm and steam it in steam at 90-95°C for 1 minute to form a semi-cooked rice sheet; S5: Put the rice sheet into an extrusion device and extrude and form it through a die with a pore diameter of 1.5-2.0 mm; S6: Immediately steam the extruded rice noodles in steam at 95-100°C for 3 minutes and 30 seconds to achieve complete cooking; S7: After the cooked rice noodles are quickly cooled in cold water at 5-10°C, they are then bagged or boxed.

[0009] Further, in the S1, the mass-volume ratio of the rice to the warm water is 1:1.2-1:1.5, and the water temperature fluctuation is kept ≤5°C during the soaking process.

[0010] Further, in the S2, the single washing time is 2-5 minutes, and the content of free starch on the rice surface after draining is ≤1.5%.

[0011] Further, in the S3, the water content of the rice milk is controlled at 65%-70%, and the rotation speed of the grinding equipment is 2000-3000 revolutions per minute.

[0012] Further, in the S4 and S6, a continuous steam device is adopted.

[0013] Further, between the S5 and S6, seamless connection is adopted by a conveyor belt, and the time interval from the completion of wire extrusion to the entry of the rice noodles into the re-steaming equipment is ≤30 seconds.

[0014] Further, in S7, the residence time of the rice noodles in cold water is 35 to 40 minutes, and the surface temperature of the rice noodles after cooling is ≤ 15°C. Beneficial effects

[0015] 1. The new Mengzi fragrant rice processing technology applicable to plateau areas of the present invention realizes continuous operation; 2. The rice noodles prepared by the technology of the present invention have a high gelatinization degree, good texture, excellent smoothness, and the storage time at room temperature is extended to 24 hours; 3. The present invention breaks through the plateau boiling point limit through two-stage temperature control, with uniform ripening and stable forming, solving the problems of insufficient secondary processing ripening and broken strip adhesion in the traditional process. Description of the drawings

[0016] Figure 1 It is a schematic diagram of the processing process flow of the present invention. Specific embodiments

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0018] I. Implementation scenario and raw material selection Scenario: A rice noodle factory in Kunming, Yunnan (altitude 1890 meters, atmospheric pressure 81 kPa, water boiling point 93.7°C) Raw materials: Local indica rice in Yunnan (amylose content 21%, broken rice rate 4%), meeting the standard of GB / T 1350-2018.

[0019] II. Detailed operation steps of the whole process chain S1: The warm water soaking equipment is a stainless steel constant temperature soaking tank (volume 500L, with a water circulation temperature control system) Parameter control: 100 kg of rice + 130 L of warm water Water temperature: [40 ± 2] °C (monitored in real time through the temperature control system, fluctuation ≤ 2 °C) Soaking time: 40 hours Operation key points: Remove impurities and bad rice before soaking to ensure the integrity of the rice grains; Stir once every 12 hours to make the rice grains absorb water evenly; Endpoint judgment: Randomly take 10 rice grains, crush them, and there is no white hard core, and the water absorption rate reaches 65%.

[0020] S2: Number of cleaning times: 3 times; Single cleaning time: 3 minutes; Operation key points: Drain the soaked rice for 5 minutes, then proceed to the next washing step to avoid excessive moisture during grinding; After washing, detect the free starch content on the surface of the rice: 1.2% (determined by iodine colorimetry).

[0021] S3: The grinding equipment is a vertical colloid mill (model JM-L100, rotation speed 2800 revolutions per minute) Parameter control: Grinding particle size: 90 mesh (detected by an 80-mesh sieve) Moisture content of rice milk: 68% (determined by the gravimetric method) Operation key points: Feed in batches, with each feed volume being 70% of the volume of the grinding machine to avoid overloading; Immediately transfer to the steaming sheet link after grinding to prevent starch sedimentation.

[0022] S4: The steaming sheet equipment is a continuous steam jacketed pan (steaming tray size 120cm×60cm×5cm, with a temperature sensor) Parameter control: Spreading thickness of rice milk: 2.5cm Steam temperature: 93℃ Steaming time: 1 minute Operation key points: Pre-coat the steaming tray with food-grade vegetable oil (usage 5g / m²) to prevent the rice milk from sticking; Maintain a steam pressure of 0.12MPa during the steaming process to ensure stable temperature; Endpoint judgment: The surface of the rice flakes is semi-transparent, there is no sticky pulp when inserted with chopsticks, and the gelatinization degree reaches 70%.

[0023] S5: The wire extrusion equipment is a screw extrusion molding machine (model MT-60, screw rotation speed 150 revolutions per minute, die hole diameter 1.8mm) Parameter control: Feeding temperature: ≥80℃ (to maintain the plasticity of the rice flakes) Wire extrusion speed: 8m / min Operation key points: The rice flakes are seamlessly connected to the feeding port of the extruder through a conveyor belt (interval time 20 seconds); Observe the wire extrusion state in real time. If there is a broken strip, immediately adjust the screw pressure.

[0024] S6: The re-steaming equipment is a tunnel-type steam steamer (length 10m, temperature controlled in three sections, with a mesh belt conveyor device) Parameter control: Temperature of the first section: 95℃ (preheating zone, duration 30 seconds) Second-stage temperature: 98°C (core ripening zone, duration 2 minutes and 30 seconds) Third-stage temperature: 90°C (heat equalization zone, duration 30 seconds) Operation key points: Redouble steaming duration: 3 minutes and 30 seconds; steam is boosted to near atmospheric boiling point through a pressure compensation device (external boiler, pressure 0.3 MPa) to ensure a gelatinization degree of 97%; An infrared thermometer is set at the outlet, and the central temperature of the rice noodles is 97°C.

[0025] S7: The cooling equipment is a three-stage cold water tank (length 5 m, width 0.8 m, water temperature decreasing step by step: 15°C → 10°C → 5°C) Parameter control: Cooling time: 35 minutes Packaging specification: 200 g / bag (food-grade PE bag, vacuum packaging) Operation key points: The surface temperature of the rice noodles drops to 12°C after cooling; It is immediately transferred to a normal-temperature warehouse (temperature 20 - 25°C, humidity 60%) for storage after packaging.

[0026] III. Key process comparison and effect verification

[0027] IV. Equipment linkage and intelligent control Control system: Adopt a PLC programmable controller, integrating 12 monitoring points such as temperature, time, and pressure, and generating a process curve in real time; Data traceability: Key parameters (such as the water temperature for soaking rice and steaming time) are automatically stored, and the storage period is ≥2 years, meeting the requirements of food safety traceability; Energy-saving design: The waste heat of the steaming box is recovered through a heat exchanger and used to preheat the water for soaking rice, reducing energy consumption by 25% compared with the traditional process.

[0028] V. Process scalability description Raw material compatibility: In addition to Mengzi fragrant rice, it is compatible with japonica rice (adjust the soaking time to 48 hours) and mixed rice (such as indica rice: japonica rice = 7:3), broadening the product categories; Production capacity adjustment: By increasing or decreasing the number of steaming trays and adjusting the conveyor belt speed, the production capacity of a single production line can be flexibly switched between 500 - 1500 kg / day; Geographical expansion: In areas with an altitude of 1500 - 2000 meters (such as some areas in Guizhou and Sichuan), it can be directly applied with only a fine adjustment of the redouble steaming temperature (±2°C).

[0029] Compared with the traditional process, that is, grinding the rice into pulp, fermenting it, and then cooking the rice noodles until they are cooked through boiling water; the optimized process is to ferment in advance and use steam to cook the rice noodles until they are cooked. It has the advantages of one-time molding, strong adaptability to the plateau environment, and stable product quality, and solves the problems of long fermentation time, cumbersome secondary processing, and poor quality of rice noodles in the prior art.

[0030] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0031] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A new processing technology for Mengzi fragrant rice applicable to plateau areas, characterized in that, It includes the following steps: S1: Soak the rice in warm water at 30~50°C for 36 to 48 hours until the rice grains are fully swollen by absorbing water and can be crushed without a hard core; S2: Wash the soaked rice at least 3 times repeatedly to remove surface impurities and free starch; S3: Grind the washed rice into a delicate rice slurry with a particle size of 80~100 mesh; S4: Spread the rice slurry into a rice slurry layer with a thickness of 2~3 cm and steam it in steam at 90~95°C for 1 minute to form semi-cooked rice flakes; S5: Put the rice flakes into an extrusion device and extrude them into filaments through a die with a pore diameter of 1.5~2.0 mm; S6: Immediately steam the extruded rice noodles in steam at 95~100°C for 3 minutes and 30 seconds to achieve complete cooking; S7: After the cooked rice noodles are cooled by stratification in cold water at 10~15°C, then bag or frame them.

2. The processing technology according to claim 1, characterized in that, In S1, the mass-volume ratio of rice to warm water is 1:1.2~1:1.5, and the water temperature fluctuation is kept ≤5°C during the soaking process.

3. The processing technology according to claim 1, characterized in that , In S2, the single washing time is 2~5 minutes, and the content of free starch on the surface of the drained rice is ≤1.5%.

4. The processing technology according to claim 1, characterized in that, In S3, the water content of the rice slurry is controlled at 65%~70%, and the rotation speed of the grinding equipment is 2000~3000 revolutions per minute.

5. The processing technology according to claim 1, characterized in that, In S4 and S6, a continuous steam equipment is adopted.

6. The processing technology according to claim 1, characterized in that Between S5 and S6, a conveyor belt is used for seamless connection, and the time interval from the completion of filament extrusion to the entry of the rice noodles into the re-steaming equipment is ≤30 seconds.

7. The processing technology according to claim 1, characterized in that, In S7, the residence time of the rice noodles in cold water is 35~40 minutes, and the surface temperature of the cooled rice noodles is ≤15°C.

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