Polished round-grained rice noodles capable of slowly increasing sugar and controlling appetite and preparation method of polished round-grained rice noodles

Abstract

The invention belongs to the technical field of grain deep processing and functional food, and particularly relates to polished round-grained rice noodles capable of slowly increasing sugar and controlling appetite and a preparation method of the polished round-grained rice noodles. Water is added into the soaked broken rice for crushing and pulping, and primary rice milk is prepared; filtering the primary rice milk through a filter screen to obtain fine and uniform rice milk; fully stirring and mixing the rice milk and potato protein powder to obtain mixed pulp; heating and gelatinizing the mixed slurry, stopping heating when the slurry becomes uniform paste, and cooling to obtain gelatinized gel; potato starch is added into the gelatinized gel, and the mixture is fully kneaded into uniform dough; and extruding the dough into thin strips through a single-screw extruder, curing the thin strips with boiling water, and cooling the thin strips with supercooled water to increase toughness so as to prepare the polished round-grained rice noodles capable of slowly increasing the sugar content and controlling the appetite. The potato protein and the potato starch are added, so that the improvement of the texture of the product and the endowment of double health functions of slowly increasing sugar and controlling appetite are synchronously realized.

Description

Technical Field

[0001] This invention belongs to the field of grain deep processing and functional food technology, specifically involving a slow-release, appetite-controlling japonica rice noodle and its preparation method. It uses broken rice, a by-product of japonica rice processing, as the main raw material, and adds potato protein and potato starch to synergistically improve its processing performance, eating quality and metabolic regulation function. Background Technology

[0002] my country is a major producer and consumer of rice. During the processing of northern japonica rice into polished rice, approximately 10-20% of the rice is broken. However, the variety of deep-processed products from this broken rice is limited, and its utilization rate is low. Rice noodles, a staple food popular with the general public, especially young people, are one of the main products from the deep processing of broken rice.

[0003] In the process of making rice noodles, starch undergoes three stages: gelatinization, shaping, and aging. During gelatinization, amylopectin provides viscosity, while amylose molecules are released. During cooling and shaping, amylose rapidly rearranges through hydrogen bonds to form a strong three-dimensional gel network, constituting the "skeleton" of the rice noodles and giving them chewiness and elasticity. In the subsequent aging stage, the short chains of amylopectin slowly crystallize, further strengthening the network and improving its resistance to cooking. Therefore, rice noodles are usually made from indica rice (which contains a relatively high amount of amylose, about 20%-28%). Japonica rice, on the other hand, has a high amylopectin content (80%-85%) and a low amylose content (15%-20%). Using Japonica rice to make rice noodles results in poor thermal gelation properties, a loose network structure, and insufficient strength. The resulting rice noodles generally suffer from problems such as easy breakage, insufficient toughness and elasticity, a hard texture, and significant loss during cooking, severely limiting its application in high-quality rice noodle products and relegating it more to a low-value filler.

[0004] To improve the aforementioned textural defects, existing technologies typically employ the combination of exogenous starches (such as corn starch and potato starch) or the addition of gluten strengtheners and shaping agents. While these methods can improve the elasticity and smoothness of products to some extent, they also lead to several problems: the addition of extra starch often increases the total digestible carbohydrate content of the product, resulting in a looser structure, which may actually accelerate digestion and cause a more severe postprandial glycemic response, leading to an increased glycemic index (GI). This contradicts the modern consumer demand for "low glycemic index" healthy staple foods. Furthermore, the use of various additives violates the "cleanliness" label on food products.

[0005] Meanwhile, market demand for staple foods has shifted from simply providing satiety to offering both excellent taste and health benefits, such as foods that enhance satiety and stabilize post-meal blood sugar. Traditional rice noodles and their improved technologies cannot simultaneously meet the dual goals of "texture improvement" and "functional enhancement." The industry faces a bottleneck: measures taken to improve the texture of broken rice noodles may come at the expense of their metabolic health properties. Therefore, developing an innovative method that can strengthen the gel network of broken japonica rice noodles while simultaneously endowing them with the dual functions of slow-release carbohydrates and promoting satiety has become a key problem urgently needing to be solved in this field. Summary of the Invention

[0006] To address the problems of poor texture, easy breakage, rapid digestion leading to high glycemic response, and lack of active satiety regulation in existing rice noodles made from broken Japonica rice, this invention provides a slow-release, appetite-controlling Japonica rice noodle and its preparation method. This method simultaneously improves the product's texture and imparts the dual health benefits of "slow-release, appetite-controlling" by adding potato protein and potato starch.

[0007] This invention is achieved by providing a method for preparing slow-release, appetite-controlling japonica rice noodles, comprising the following steps: Step 1: Soak the broken rice grains in water until they fully absorb water and soften. Step 2: Add water to the soaked rice from Step 1 and grind it into a paste to obtain a primary rice paste; Step 3: Filter the primary rice slurry obtained in Step 2 through a filter screen to remove large particles of impurities that have not been fully crushed, and obtain a fine and uniform rice slurry. Step 4: Thoroughly mix the rice slurry obtained in Step 3 with the potato protein powder to obtain a mixed slurry; Step 5: Heat the mixed slurry obtained in Step 4 to gelatinize it. Stop heating when the slurry becomes a uniform paste and cool it down to obtain a gelled gel. Step 6: Add potato starch to the gelatinized gel obtained in step 5 and knead thoroughly to form a uniform dough; Step 7: Extrude the dough obtained in Step 6 into thin strips using a single-screw extruder, cook it in boiling water, and then cool it in cold water to increase its elasticity, thus obtaining slow-release sugar-controlled appetite-regulating japonica rice noodles.

[0008] Preferably, in step 1, the soaking time is 5-7 hours.

[0009] Preferably, in step 2, the water added accounts for 140% of the dry weight of the broken rice.

[0010] Preferably, in step 3, the filter screen is 50 mesh.

[0011] Preferably, in step 4, the mass of potato protein powder added is 5-7g, and the stirring is performed using magnetic stirring for 30 minutes.

[0012] Preferably, in step 5, the mixed slurry is gelatinized in a boiling water bath for 15-25 minutes, with continuous stirring during the gelatinization process, and the temperature is lowered to 40-65℃ after complete gelatinization.

[0013] Preferably, in step 6, the mass of potato starch added is 60g.

[0014] A slow-release, appetite-controlling rice noodle dish is provided, prepared according to the method described above.

[0015] Compared with the prior art, the advantages of the present invention are as follows: 1. Synergistic Innovation of Texture and Function: This invention is the first to apply potato protein to a japonica rice noodle system. Its thermogelation properties strengthen the network structure of the noodles, improving texture and chewiness. The application of potato starch effectively reduces the breakage rate of the noodles. Simultaneously, the digestive properties of potato protein endow the product with dual health benefits: a "slow-rise" glycemic index and appetite control via the CCK pathway. The mechanism involves a negative feedback loop between trypsin and CCK. The core of this mechanism is that after eating, cholecystokinin (CCK) secreted by the small intestinal mucosa significantly promotes the secretion of digestive enzymes (including trypsinogen) by the pancreas. When trypsinogen is activated in the small intestine and reaches an effective concentration, its active form—trypsin—hydrolyzes specific signaling molecules (such as CCK-releasing peptides) in the small intestinal lumen, thereby eliminating stimulation of CCK secretion. This ultimately leads to a decrease in CCK levels and a timely reduction in pancreatic secretion. This invention, by inhibiting trypsin activity to a certain extent, promotes CCK accumulation, thereby enhancing satiety and suppressing appetite.

[0016] 2. Resolving traditional contradictions: This invention overcomes the technical contradiction that traditional methods of improving texture by adding starch lead to a large increase in glycemic index (GI). Through a protein-starch composite structure, this invention achieves a lower glycemic response while improving texture. 3. Clean and efficient process: It replaces multiple starches or synthetic colloids that may be required with a single natural protein component. The process is simple, in line with the clean label trend, and easy to industrialize. Attached Figure Description

[0017] Figure 1 A comparative graph showing the effect of different amounts of potato starch added on the breakage rate of rice noodles; Figure 2 The inhibitory effect of different concentrations of potato protein on trypsin; Figure 3 A comparative graph showing the effect of different amounts of potato protein added on rice noodles; Figure 4 In vitro simulated digestion data of rice noodles with different amounts of potato protein added; Figure 5Protein content in the gastric digestive supernatant of rice noodles with different amounts of added potato protein. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, a further detailed description is provided below in conjunction with the accompanying drawings, embodiments, and experimental results. It should be understood that the specific content described herein is for explanation and support only and is not intended to limit the invention.

[0019] This invention synergistically improves the quality and function of broken rice noodles by adding potato protein and potato starch. To determine the optimal addition amount of each, a single-factor experiment was first designed, using breakage rate and in vitro simulated starch digestibility as key indicators for optimization. Subsequently, trypsin inhibition rate was measured to verify its potential to stimulate CCK secretion and control appetite.

[0020] I. Determination of Physicochemical Indicators of Rice Noodles 1. Breakage rate: Take a fixed amount of finished rice noodles, steam them until they are at their best cooking state, drain them, carefully pick out the broken parts, weigh them, and calculate the percentage of the broken rice noodles in the total mass. 2. In vitro simulated starch digestion experiment: Following the Englyst method with slight modifications, a sample containing 400 mg of starch was taken and digested at 37°C with 15 mL of sodium acetate buffer (pH 5.2) and 5 mL of mixed enzyme solution (containing pancreatic α-amylase and glucoamylase) at 37°C. Samples were taken at 20, 60, and 120 min, and the reducing sugar content was immediately determined using the DNS method to calculate the starch hydrolysis rate.

[0021] 3. Trypsin inhibition rate assay: The inhibition rate against trypsin was determined using the classic BAPNA method, as detailed below: The following are the specific experimental procedures based on the "GB 5009.224—2016 National Food Safety Standard: Determination of Trypsin Inhibitor Activity in Soybean Products": (1) Solution preparation ① Reagent List Hydrochloric acid (HCl); glacial acetic acid (CH3COOH); sodium hydroxide (NaOH); calcium chloride (CaCl2·2H2O); trypsin (-20℃ frozen storage); benzoyl-L-arginine-p-nitroaniline (BAPNA); tris(hydroxymethyl)aminomethane (Tris); dimethyl sulfoxide (DMSO) ② Reagent preparation 6 mol / L hydrochloric acid: Dilute with 50 mL HCl + water to 100 mL 1 mol / L hydrochloric acid: Dilute with 83 mL HCl + water to 1000 mL 0.1 mol / L hydrochloric acid: Dilute with 8.3 mL HCl + water to 1000 mL 0.001 mol / L hydrochloric acid: Dilute 1 mL of 1 mol / L hydrochloric acid with water to 1000 mL. 5.3 mol / L acetic acid: Dilute 30 mL of glacial acetic acid with water to 100 mL. 0.01 mol / L NaOH: Dissolve 0.40 g of NaOH in 500 mL of water, then dilute to 1000 mL. Calcium chloride hydrochloric acid solution: Dissolve 0.735 g CaCl₂·2H₂O in 1 L of 0.001 mol / L HCl, and adjust the pH to 3.0 ± 0.1. Trypsin stock solution: Dissolve 27.0 mg trypsin in calcium chloride hydrochloric acid solution and bring the volume to 100 mL (store at 0~4℃, ≤5 days). Trypsin working solution: 5.0 mL stock solution + calcium chloride hydrochloric acid solution to a final volume of 100 mL. Tris-CaCl2 buffer: 6.05 g Tris + 0.735 g CaCl2 + 900 mL water, adjust pH to 8.2±0.1, and bring volume to 1000 mL. BAPNA solution: Dissolve 60 mg BAPNA in 1 mL DMSO, transfer with Tris-CaCl2 buffer and bring the volume to 100 mL (prepare fresh before use). ③ Experimental Procedure Dilute the supernatant of the digestion product to an appropriate concentration with Tris-HCl buffer. Transfer 2 mL of the sample solution and Tris-HCl buffer (as a standard solution) to 10 mL test tubes, add 5 mL of BAPNA solution to each tube, mix, and incubate at 37°C for 10 min. Then, add 2.00 mL of trypsin solution, mix immediately, and allow the mixture to react precisely at 37°C for 10 min. Immediately stop the reaction by adding 1 mL of glacial acetic acid solution to a test tube. Measure the OD values. 410 The values ​​were recorded (denoted as As and Ar standards, respectively). Simultaneously, a blank control group was established by adding 2 mL of trypsin solution after adding glacial acetic acid solution (denoted as Abs and Abr, respectively). Three replicates were prepared for each sample.

[0022] ④ Inhibition rate calculation: The inhibition rate of the sample extract is calculated using the formula: i = [(Ar - Abr) - (As - Abs)] / (Ar - Abr) × 100% In the formula: i ———Inhibition rate; Ar ——— Absorbance of the standard solution; Abr ——— Absorbance of the standard blank solution; As ———Absorbance of the sample solution; Abs ——— Absorbance of the blank sample solution; 100% — Conversion factor.

[0023] A higher inhibition rate indicates a stronger inhibitory effect of digestive products on trypsin, indirectly suggesting that it may more effectively promote CCK accumulation to suppress appetite.

[0024] 4. Preparation of digestion products and determination of protein concentration in the supernatant Preparation of digestion products: The internationally recognized INFOOGS 2.0 static in vitro digestion model was used to simulate oral and gastric digestion. Appropriate samples were taken and reacted sequentially with simulated saliva and simulated gastric juice under standard conditions. After 2 hours of gastric digestion, the gastric digestion products from the simulated digestion process were collected, centrifuged, and the supernatant was used as the test sample.

[0025] 5. Sensory evaluation: The sensory evaluation of rice noodles was conducted using a scaling method, following the GB / T-15682-2008 standard. The evaluation items included odor, appearance, palatability, taste, and texture. The sensory evaluation table is shown below.

[0026] Table 1. Sensory rating criteria II. Examples and Data Analysis Example 1 (no potato protein, only potato starch added): Using 100g of broken rice as the main raw material, without adding potato protein, only adding 0, 40, 60, and 80g of potato starch, it was prepared according to the basic process of this invention, the breakage rate was calculated and in vitro simulated digestion was performed.

[0027] The product has a 100% breakage rate without potato starch, but the breakage rate decreases significantly with the addition of potato starch. Based on the sensory characteristics and actual needs of the rice noodles, an addition amount of 60g of starch is most suitable. Figure 1 As shown in Table 2, the weights from left to right are 0, 40, 60, and 80g, and the breakage rate is shown in Table 2.

[0028] Table 2. Breakage rate of rice noodles with different amounts of potato starch added. Starch addition amount / g Broken strip rate / % 0 99.9 40 37.5 60 18.0 80 13.3 Example 2 Experiments were conducted to investigate the trypsin inhibition of different concentrations of potato protein (10, 50, 100 mg / mL).

[0029] Experiments were conducted on potato protein at different concentrations to inhibit trypsin activity. The results showed that potato protein effectively inhibited trypsin activity. Furthermore, since trypsin and CCK form a negative feedback regulatory loop, the product's ability to resist protease digestion during digestion can promote CCK accumulation and send signals to the central nervous system, thereby suppressing appetite and enhancing satiety. Figure 2 As shown.

[0030] Example 3 Based on the results of Example 1, the amount of potato protein added was investigated: Using 100g of broken rice as the main raw material, 60g of potato starch and 0, 3, 5 and 7g of potato protein were added. The mixture was prepared according to the basic process of this invention and subjected to in vitro simulated digestion.

[0031] After adding potato protein, the product showed no significant difference in breakage rate. In vitro digestion simulation data showed that the digestibility of the potato protein-added group was significantly lower than that of the pure rice noodle group, proving that the addition of potato protein effectively inhibited starch hydrolysis. Figure 3 (From left to right: 0g, 3g, 5g, 7g) Figure 4 As shown.

[0032] Example 4 The protein content of the supernatant after centrifugation of the products from the gastric digestion stage was detected using a rapid BCA reagent kit.

[0033] After undergoing oral-gastric digestion, the protein concentration in the supernatant of this product is very low, such as... Figure 5 As shown, this indicates that the product has a certain resistance to protease digestion and can maintain a relatively stable and intact structure. It also reflects that the product digests slowly during digestion, which helps to delay gastric emptying.

[0034] III. Optimal Process Products: Table 3. Sensory scores of rice noodles with different amounts of potato protein added. Different PP contents / g 0 3 5 7 score 68 70.5 77.5 80 1. Sensory rating scale analysis: This invention discovers that the addition of potato protein (PP) significantly improves the quality of rice noodles. As the PP addition amount increases within the range of 0g-7g, the overall sensory score of the rice noodles shows a continuous upward trend, increasing from 68 points to 80 points (out of 100), indicating that PP can systematically improve the edible quality of the product. Specifically, the addition of PP effectively enhances the elasticity and toughness of the rice noodles, improves their smoothness, and maintains a good appearance, color, and aroma. When the addition amount is 5g-7g, the sensory quality reaches a superior level, proving that an appropriate amount of potato protein can effectively optimize the textural properties and overall acceptability of rice noodles, demonstrating clear value for process improvement and application prospects. 2. Process Determination Based on experimental data and sensory evaluation, the optimal process of this invention (100g broken rice, 5-7g potato protein, 60g potato starch) was obtained for preparing rice noodles. The breakage rate was significantly reduced to below 20%, and in vitro simulated starch digestion results showed that its starch hydrolysis curve was much lower than that of the sample group without added protein.

Claims

1. A method for preparing slow-release, appetite-controlling japonica rice noodles, characterized in that, Includes the following steps: Step 1: Soak the broken rice grains in water until they fully absorb water and soften. Step 2: Add water to the soaked rice from Step 1 and grind it into a paste to obtain a primary rice paste; Step 3: Filter the primary rice slurry obtained in Step 2 through a filter screen to remove large particles of impurities that have not been fully crushed, and obtain a fine and uniform rice slurry. Step 4: Thoroughly mix the rice slurry obtained in Step 3 with the potato protein powder to obtain a mixed slurry; Step 5: Heat the mixed slurry obtained in Step 4 to gelatinize it. Stop heating when the slurry becomes a uniform paste and cool it down to obtain a gelled gel. Step 6: Add potato starch to the gelatinized gel obtained in step 5 and knead thoroughly to form a uniform dough; Step 7: Extrude the dough obtained in Step 6 into thin strips using a single-screw extruder, cook it in boiling water, and then cool it in cold water to increase its elasticity, thus obtaining slow-release sugar-controlled appetite-regulating japonica rice noodles.

2. The preparation method of the slow-release, appetite-controlling japonica rice noodles according to claim 1, characterized in that, In step 1, the soaking time is 5-7 hours.

3. The preparation method of the slow-release, appetite-controlling japonica rice noodles according to claim 1, characterized in that, In step 2, the added water accounts for 140% of the dry weight of the broken rice.

4. The method for preparing slow-release, appetite-controlling japonica rice noodles according to claim 1, characterized in that, In step 3, the filter screen is 50 mesh.

5. The method for preparing slow-release, appetite-controlling japonica rice noodles according to claim 1, characterized in that, In step 4, add 5-7g of potato protein powder and stir magnetically for 30 minutes.

6. The method for preparing slow-release, appetite-controlling japonica rice noodles according to claim 1, characterized in that, In step 5, the mixed slurry is gelatinized in a boiling water bath for 15-25 minutes, with continuous stirring during the gelatinization process. After complete gelatinization, the temperature is lowered to 40-65℃.

7. The method for preparing slow-release, appetite-controlling japonica rice noodles according to claim 1, characterized in that, In step 6, the mass of potato starch added is 60g.

8. A type of slow-release, appetite-controlling rice noodle soup, characterized in that, It is prepared according to the method described in any one of claims 1-7.

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