Fine dried noodles with low glycemic index and preparation method thereof

Abstract

The invention discloses fine dried noodles with a low glycemic index and a preparation method of the fine dried noodles. The fine dried noodles are prepared from the following production raw materials: high-amylose corn starch subjected to alkaline hydrothermal modification and a composite structure base material, the composite structure base material is formed by compounding highland barley flour, vital gluten and wheat flour. The preparation method comprises the following steps: premixing the vital gluten and the wheat flour, and adding water for the first time to prepare a mixture 1; premixing modified starch and coarse cereal powder, and then adding water for the second time to prepare a mixture 2; and mixing the two mixtures, stirring, fermenting, rolling, cutting into strips, and drying. The invention has the following advantages: 1) through the synergistic effect of the high-amylose corn starch hydrothermally modified by the alkaline method and the composite structure base material with a specific ratio, the prepared fine dried noodles have significantly reduced glycemic index; the method has the advantages of low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index, low glycemic index and good glycemic index.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a noodle product with a low glycemic index (GI), its preparation method, and its application in foods for controlling postprandial blood sugar. Background Technology

[0002] Noodles are one of China's traditional staple foods, widely loved by consumers for their ease of cooking and affordability. According to statistics from the Chinese Institute of Food Science and Technology's Noodle Products Branch, the current annual consumption of various noodle products in my country exceeds 10 million tons, with a market size exceeding 150 billion yuan. Chinese noodles are typically made from wheat flour, with salt, cooking oil, sodium carbonate, and other auxiliary ingredients, processed through steps such as kneading, sheeting, cutting, hanging, and drying (or not drying).

[0003] Starchy foods such as noodles are a significant source of dietary energy, accounting for over 50% of the diet of Chinese residents and forming an important part of a balanced diet. These foods easily induce a feeling of fullness but also tend to cause a rapid rise in postprandial blood sugar. To measure the impact of starchy foods on postprandial blood sugar, Jenkins et al. proposed the concept of the Glycemic Index (GI), which is defined as the ratio of the area under the blood glucose curve 2 hours after consuming 50 g of carbohydrate-containing food to the area under the blood glucose curve 2 hours after consuming 50 g of white bread. Based on their GI values, everyday foods can be divided into three categories: foods with a GI value higher than 70 are high-GI foods, foods with a GI value higher than 55 but lower than 70 are medium-GI foods, and foods with a GI value lower than 55 are low-GI foods.

[0004] Against the backdrop of rising global prevalence of diabetes and obesity, the traditional diet, dominated by high-GI foods, is becoming a serious public health challenge. A low-GI diet, by selecting foods that allow for a stable rise in blood sugar, helps with weight management and reduces the risk of type 2 diabetes and cardiovascular disease, playing a significant role in improving public health. Therefore, it is urgent to strengthen food science and technology innovation, promoting the development of low-GI staple foods and processed foods that are delicious, convenient, and cost-effective, thereby optimizing the national dietary structure and curbing the spread of obesity and related metabolic diseases at their source. Therefore, in dietary practice, using starches with low digestibility to replace refined starches is one of the effective strategies for achieving the goals of a low-GI diet.

[0005] High-amylose corn starch is extracted from corn varieties bred using breeding technology. Its amylose content can reach 50%–90%, significantly higher than ordinary corn starch (20%–30%). Due to its predominantly linear, tightly packed molecular structure, it exhibits resistance to gelatinization, good film-forming properties, and high gel strength. In terms of health, high-amylose corn starch is a naturally resistant starch, difficult to completely digest and absorb in the small intestine, thus having a lower glycemic index (GI value), which helps in blood sugar management, increases satiety, and can be fermented by colonic microorganisms to produce beneficial short-chain fatty acids, promoting gut health. However, these characteristics also present processing challenges: its low water absorption and swelling capacity result in poor dough extensibility, and its high gelatinization temperature necessitates higher cooking temperatures and longer cooking times.

[0006] Therefore, it is essential to develop a type of dried noodle with a low glycemic index that can solve the above-mentioned technical problems and its preparation method. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a low glycemic index noodle, its preparation method, and its application. This invention treats high-amylose corn starch using a specific alkaline hydrothermal modification technique and combines it with an optimized composite matrix (the core of which consists of barley flour, gluten, and wheat flour, and can be expanded to include oat flour and / or buckwheat flour). This, coupled with a unique step-by-step water addition process, synergistically achieves a balance between a low glycemic index, excellent processing performance, and superior eating quality in the noodle product.

[0008] The technical solution adopted by the present invention is as follows: In the first aspect, the present invention provides a low glycemic index noodle, characterized in that it is prepared from a raw material formula comprising the following parts by mass: 25-40 parts of alkaline hydrothermal modified high amylose corn starch, and 60-75 parts of a composite structural base material; the composite structural base material is composed of highland barley flour, gluten flour and wheat flour in a mass ratio of (10-25):(15-25):(20-40); the noodle further comprises edible salt comprising 0.1-0.3 parts by mass of the raw material formula.

[0009] Choosing 25-40 parts modified starch is based on a balance point verified by extensive experiments: below this range, the GI reduction effect is not significant; above this range, the dough processing performance deteriorates sharply, making it difficult to shape. The specific ratio of 60-75 parts of the composite matrix and its internal highland barley flour, gluten, and wheat flour is crucial to ensuring a stable gluten network, providing necessary extensibility and a good texture even after incorporating a large amount of modified starch. Highland barley flour is rich in dietary fiber such as β-glucan, which helps to further reduce the GI value and increase nutrition; gluten (wheat gluten protein) is key to enhancing dough strength; wheat flour provides basic gluten and flavor. Salt not only adjusts the flavor but also strengthens the gluten structure to some extent.

[0010] Preferably, the raw material formulation further includes whole grain flour, which accounts for 1% to 30% of the total mass of the raw material formulation. The whole grain flour includes oat flour and / or buckwheat flour. Oat flour and buckwheat flour are both low-GI healthy grains; their addition can further enrich the product's dietary fiber, vitamin, and mineral content, and impart a unique flavor. Simultaneously, within the framework of this invention, it does not affect the core processing and textural properties, providing flexibility in the product formulation.

[0011] Preferably, the preparation method of the alkaline hydrothermal modified high amylose corn starch includes the following steps: mixing high amylose corn starch with an amylose content ≥50% with a sodium carbonate solution of 2%–4% by mass, wherein the mass ratio of starch to sodium carbonate solution is 1:(2.5–4), heating and stirring at 80℃–95℃ for 4–8 hours, followed by homogenization, and then adding ethanol with a volume concentration of 93%–98% for precipitation, wherein the volume ratio of ethanol to starch milk is 1:1–1.5:1, stirring evenly, allowing to stand, centrifuging, washing, and drying to obtain the alkaline hydrothermal modified high amylose corn starch. This modification method is one of the key aspects of this invention. Under heating conditions, alkali (sodium carbonate) can promote partial hydrolysis and structural rearrangement of starch granules, significantly improving their cold water solubility and limiting the exudation of amylose. Experiments show that only high-amylose corn starch modified by alkali hydrothermal treatment can undergo a synergistic reaction with the composite matrix of this invention during preparation, thereby improving its hydration and dispersion behavior in subsequent dough preparation and solving its problems of hydrophobicity and difficulty in mixing. The subsequent alcohol precipitation step is not simply dehydration; it helps to terminate the reaction, purify the modified starch, and may induce specific orientations or aggregations of amylose molecules. This improves processability while maximally preserving its digestibility-resistant crystalline core, which is key to achieving a synergistic effect of "easy processing" and "low digestibility."

[0012] Furthermore, the barley flour is preferably whole barley flour with a β-glucan content ≥5%; the gluten powder has a protein content ≥75%; and the wheat flour is preferably high-gluten wheat flour with a wet gluten content ≥30%. These requirements for raw material quality are to ensure the functionality of the composite structure matrix and to ensure the stability of the final product performance.

[0013] In a second aspect, the present invention provides a method for preparing the above-mentioned low glycemic index noodles, characterized by comprising the following steps: S1. Raw material preparation: Weigh each raw material according to the raw material formula; S2. First mixing: Mix the wheat gluten with the wheat flour, add the first portion of water, and stir for 5-8 minutes to obtain mixture 1; the amount of the first portion of water added is 15%-25% of the total mass of the wheat gluten and wheat flour; S3. Second mixing: Mix the alkaline hydrothermal modified high amylose corn starch, the highland barley flour, and the optional miscellaneous grain flour. Dissolve the edible salt in the second part of water, add the salt water to the powder mixture, and stir for 8-10 minutes to obtain mixture 2. The amount of the second part of water added is 25%-45% of the total mass of the alkaline hydrothermal modified high amylose corn starch, highland barley flour, and optional miscellaneous grain flour. S4. Final mixing and dough resting: Combine the mixture 1 and the mixture 2, stir and mix for 5-8 minutes to obtain the final mixture, and then let the dough rest. S5. Rolling and cutting: The final mixture after the dough has rested is rolled into a sheet with a thickness of 1-3 mm using a rolling mill, and then cut into strips to obtain wet noodles; S6. Drying: Dry the wet noodles at 35℃~45℃ for 6~10 hours to obtain the low glycemic index noodles.

[0014] The stepwise water addition process is a core technology designed to address the significant differences in water absorption characteristics of the raw material systems in this invention. Wheat gluten and wheat flour absorb water quickly, allowing them to combine with water first to form a preliminary gluten network framework (mixture 1). Modified starch and barley flour (and other grain flours) absorb water slowly, requiring more time and more water to fully swell. Pre-mixing them with salt water (mixture 2) ensures both thorough hydration and even salt distribution. Finally, the two are mixed, allowing the initially formed gluten network to effectively intertwine with the fully swelled starch / fiber system, forming a uniform dough with good extensibility and viscoelasticity. This completely solves the problems of clumping, uneven mixing, and fragile dough structure that easily occur with traditional single-step water addition methods. The dough resting step (preferably at 25℃~30℃ and 75%~85% relative humidity for 15~30 minutes) helps to further evenly distribute moisture, fully develop the gluten, and improve the dough's processing performance.

[0015] In a third aspect, the present invention provides the application of the above-mentioned low glycemic index noodles in the preparation of foods for which postprandial blood glucose levels need to be controlled.

[0016] In a fourth aspect, the present invention provides a blood sugar control food composition, characterized in that it comprises the aforementioned low glycemic index noodles. This composition emphasizes the product's properties as a functional food ingredient.

[0017] The beneficial effects of this invention are: 1) Significant reduction in glycemic index: This invention utilizes the synergistic effect of alkaline hydrothermal modification of high amylose corn starch (which itself has low digestibility) and barley flour rich in dietary fiber (such as β-glucan) to significantly slow down the digestion rate of starch. The resulting noodle product has an estimated glycemic index (eGI) of less than 55 in vitro and a measured GI value in humans, meeting the internationally accepted low-GI food standards and making it suitable for people who need to control their blood sugar.

[0018] 2) Excellent processing performance and eating quality: Through an optimized composite base ratio (the golden triangle of barley flour, gluten, and wheat flour) and an innovative step-by-step water addition process, even with the addition of up to 40 parts modified starch, a dough with moderate softness, smoothness, uniformity, and good extensibility can still be obtained, making it easy for industrial rolling and cutting. The finished noodles do not break or cloud the broth after cooking (low cooking loss rate), and have a good elasticity, good toughness, smoothness, and non-stickiness. The sensory quality is comparable to traditional high-quality wheat noodles, achieving a balance between low GI and good taste.

[0019] 3) Synergistic effect among components: Experiments have shown that there is a clear synergistic effect among the alkaline hydrothermal modified starch, the specific ratio of composite structural base material, and the step-by-step processing technology of the present invention. The absence or alteration of any one of them (such as using unmodified starch, changing the proportion of excipients, or using a single addition of water) will lead to significant shortcomings in the product in terms of GI value, processability, or food quality, while the solution of the present invention can achieve an optimization effect far exceeding that of simply adding the components together.

[0020] 4) Flexible and nutritious formula: Based on the core formula, oat flour, buckwheat flour and other grains can be selectively added, which not only further optimizes the GI value and nutritional composition (increasing dietary fiber, protein and trace elements), but also enriches the flavor and variety of the product, meeting the diversified needs of the market. Attached Figure Description

[0021] Figure 1 This is the DSC spectrum of high amylose corn starch.

[0022] Figure 2 The effect of alkaline hydrothermal modification on the thermal processing properties (solubility) of high amylose corn starch; Figure 3 The effect of alkaline hydrothermal modification on the thermal processing properties (expansion) of high amylose corn starch; Figure 4 The effect of alkaline hydrothermal modification on the thermal processing characteristics (amylose leakage) of high amylose corn starch; Figure 5 The digestibility and eGI value of high amylose corn starch before and after alkaline hydrothermal modification are measured. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Starch Modification Examples Example S1: Preparation of Alkali-Metabolic Hydrothermal Modified High Amylose Corn Starch 1000g of high amylose corn starch (70.5% amylose content) was weighed and added to 3000g of 3% sodium carbonate solution (starch to solution mass ratio 1:3). The mixture was heated in a 90℃ water bath for 6 hours with stirring. The treated starch slurry was homogenized at 15000 r / min for 4 minutes using a high-pressure homogenizer. Then, 3000mL of 95% edible alcohol (alcohol to starch slurry volume ratio 1:1) was added to the homogenized starch slurry, stirred thoroughly, and allowed to stand at room temperature for 3 hours. Subsequently, it was centrifuged at 4000 r / min for 15 minutes, and the supernatant was discarded. The precipitate was washed twice with 70% alcohol and centrifuged again. The washed precipitate was dried to constant weight in a 55℃ forced-air drying oven, pulverized, and passed through a 100-mesh sieve to obtain alkali-modified hydrothermal high amylose corn starch, which was then sealed for later use.

[0025] Comparative Example DS1: Preparation of Conventional Hydrothermal Modified High Amylose Corn Starch Except for replacing the sodium carbonate solution with an equal mass of deionized water and omitting the alcohol precipitation step (after homogenization, centrifugation, washing with water, and drying), the remaining steps are the same as in Example S1.

[0026] Comparative Example DS2: Unmodified high amylose corn starch High amylose corn starch with an amylose content of 70.5% from the same batch as in Example S1 was used without any treatment.

[0027] Examples and Comparative Examples of Noodle Preparation Example 1 Formula: 30 parts of alkaline hydrothermal modified high amylose corn starch, 70 parts of composite structural matrix. The composite structural matrix consists of: 15 parts of highland barley flour, 20 parts of wheat gluten, and 35 parts of wheat flour. An additional 0.25 parts of edible salt (0.25% of the total powder mass) is added.

[0028] Preparation method: S1. Raw material preparation: Accurately weigh each raw material according to the above formula.

[0029] S2. First Mixing: Pour gluten powder (20 parts) and wheat flour (35 parts) into a dough mixer and premix for 1 minute. Calculate the total mass of both as 55 parts. Take 20% of the total mass of water, i.e., 11 parts of water, as the first portion of water. Start the dough mixer (stirring paddle speed 120 r / min), slowly add the first portion of water, and continue stirring for 6 minutes until the material forms a uniform flocculent material with a preliminary gluten network structure, obtaining mixture 1.

[0030] S3. Second Mixing: In another container, premix 30 parts of alkaline hydrothermal modified high amylose corn starch and 15 parts of highland barley flour evenly. Dissolve 0.25 parts of edible salt completely in the second part of water. Calculate the total mass of starch and highland barley flour to be 45 parts. Take 40% of the total mass of water, i.e., 18 parts of water (containing dissolved salt), as the second part of water. Slowly add the second part of salt water to the mixture of starch and highland barley flour, while stirring at 120 r / min for 9 minutes to ensure that the powder fully absorbs water and swells, resulting in a uniform and moist mixture 2.

[0031] S4. Final Mixing and Dough Resting: Add all of Mix 2 to the dough mixer containing Mix 1. Continue mixing at 120 rpm for 6 minutes, until all materials are evenly mixed, forming a dough (final mix) with uniform color, moderate softness, smooth surface, and good extensibility. Remove the dough, cover it with plastic wrap, and place it in a constant temperature and humidity chamber at 28℃ and 80% relative humidity for 20 minutes to rest.

[0032] S5. Rolling and Cutting: After resting, the dough is fed into a pasta machine and rolled multiple times (folding and rolling, repeated 6 times) to fully expand the gluten network. Finally, it is rolled into a continuous, smooth sheet with a thickness of 2.0 mm. The sheet is then cut into wet noodles with a width of 2.0 mm using a noodle cutter.

[0033] S6. Drying: The wet noodles are evenly suspended in a drying room and dried for 8 hours at 40°C and 60% relative humidity until the moisture content is ≤14.5%. This yields the low glycemic index noodles of the present invention, labeled as E1.

[0034] Example 2: Formula: 25 parts of alkaline hydrothermal modified high amylose corn starch, 75 parts of composite structural matrix. The composite structural matrix consists of: 20 parts of highland barley flour, 25 parts of wheat gluten, and 30 parts of wheat flour. 0.2 parts of edible salt are added.

[0035] Preparation method: Same as Example 1, with the following adjustments to the process parameters: The first water addition was calculated as 22% of the total mass of gluten and wheat flour (55 parts), which was 12.1 parts water. The second water addition was calculated as 35% of the total mass of modified starch and highland barley flour (45 parts), which was 15.75 parts water (including salt). The dough resting time was extended to 25 minutes, and the final rolled dough thickness was 1.8 mm. The resulting noodle sample was labeled E2.

[0036] Example 3: Formula: 38 parts of alkaline hydrothermal modified high amylose corn starch, 62 parts of composite structural matrix. The composite structural matrix consists of: 10 parts highland barley flour, 8 parts oat flour, 18 parts gluten, and 26 parts wheat flour. 0.3 parts edible salt are added.

[0037] Preparation method: Same as Example 1, with the following adjustments to the process parameters: The first water addition was calculated as 23% of the total mass of gluten and wheat flour (44 parts), amounting to 10.12 parts water. The second water addition was calculated as 38% of the total mass of modified starch, highland barley flour, and oat flour (56 parts), amounting to 21.28 parts water (including salt). The dough resting time was shortened to 15 minutes, and the final rolled dough thickness was 2.2 mm. The resulting noodle sample was labeled E3.

[0038] Control Experiment Design and Preparation To demonstrate the advantages of the present invention, the following comparative examples were provided. Unless otherwise specified, the total powder mass was 100 parts.

[0039] Comparative Example 1 (using only alkaline hydrothermal modified starch) Formula: Replace all of the composite structural base material (70 parts of highland barley flour, gluten, and wheat flour) in Example 1 with an equal mass of alkali-modified hydrothermal high amylose corn starch. That is, the formula is: 100 parts alkali-modified hydrothermal high amylose corn starch and 0.25 parts edible salt.

[0040] Preparation method: An attempt was made to use the same stepwise water addition process as in Example 1, but due to the lack of gluten protein, an effective dough structure could not be formed, and the material remained loose and pasty, making subsequent rolling impossible. A different approach was to add 45% (45 parts, containing salt) of water by weight of the total powder at once and stir vigorously. The resulting material was viscous but lacked gluten strength. After barely forming, it severely stuck to the rollers and broke during rolling, making it impossible to produce complete noodles. This is designated as Sample C1 (used only for some performance tests, such as eGI).

[0041] Comparative Example 2 (using only composite structural base material) Formula: Replace the alkali-method hydrothermal modified high amylose corn starch (30 parts) in Example 1 with an equal mass of high-gluten wheat flour. That is, the formula is: 15 parts highland barley flour, 20 parts wheat gluten, 65 parts wheat flour, and 0.25 parts edible salt.

[0042] Preparation method: The preparation method of Example 1 was followed exactly. The resulting noodle sample was labeled C2.

[0043] Comparative Example 3 (only barley flour was used in the composite structure matrix) Formula: Based on the formula in Example 1, replace all the gluten powder (20 parts) and wheat flour (35 parts) in the composite structural matrix with highland barley flour. That is, the formula is: 30 parts of alkaline hydrothermal modified high amylose corn starch, 70 parts of highland barley flour, and 0.25 parts of edible salt.

[0044] Preparation method: Same as in Example 1. The obtained noodle sample was marked as C3.

[0045] Comparative Example 4 (only wheat gluten was used in the composite structural matrix) Formula: Based on the formula in Example 1, replace all of the highland barley flour (15 parts) and wheat flour (35 parts) in the composite structural matrix with gluten. That is, the formula is: 30 parts of alkaline hydrothermal modified high amylose corn starch, 70 parts of gluten, and 0.25 parts of edible salt.

[0046] Preparation method: Same as in Example 1. The obtained noodle sample was labeled C4.

[0047] Comparative Example 5 (Wheat flour was used only in the composite structural matrix) Formula: Based on the formula in Example 1, replace all of the highland barley flour (15 parts) and gluten powder (20 parts) in the composite structural matrix with wheat flour. That is, the formula is: 30 parts of alkaline hydrothermal modified high amylose corn starch, 70 parts of wheat flour, and 0.25 parts of edible salt.

[0048] Preparation method: Same as in Example 1. The obtained noodle sample was marked as C5.

[0049] Comparative Example 6 (using conventional hydrothermal modified starch) Formula: exactly the same as in Example 1.

[0050] Differences in starch modification methods: "Alkaline hydrothermal modification" is replaced with "conventional hydrothermal modification". Specifically: High amylose corn starch is mixed with deionized water at a mass ratio of 1:3, heated and stirred at 90°C for 16 hours, without adding sodium carbonate. Subsequent homogenization, centrifugation, washing, and drying steps are the same, without alcohol precipitation.

[0051] Preparation method: Using this conventional hydrothermal modified starch, noodles were prepared entirely according to the formulation and process of Example 1. The resulting sample was labeled C6.

[0052] Comparative Example 7 (using vegetable oil to modify starch) Formula: exactly the same as in Example 1.

[0053] Difference in starch modification methods: Commercially available vegetable oil (palm oil) is used to modify high amylose corn starch (instead of the modified starch of this invention).

[0054] Preparation method: Using this vegetable oil to modify the starch, noodles were prepared entirely according to the formula and process of Example 1. The resulting sample was labeled C7.

[0055] Comparative Example 8 (using a single-addition water process) Formula: exactly the same as in Example 1.

[0056] Differences in preparation method: A step-by-step water addition process is not used. All powder raw materials (modified starch, barley flour, gluten, and wheat flour) are added to the dough mixer all at once. Edible salt is dissolved in 32% (32 parts) of water (100 parts) of the total powder mass and added to the dough mixer all at once. The mixture is stirred at 120 r / min for 15 minutes, then allowed to rest, be rolled, and dried. Subsequent steps are the same as in Example 1. The resulting noodle sample is labeled C8.

[0057] The effect of high amylose corn starch modification on processing properties: The gelatinization temperature range of high amylose corn starch was determined by DSC to be 88.00–104.7℃, with a peak temperature of 95.5℃. (See attached image.) Figure 1 .

[0058] High amylose corn starch was modified using a heat treatment method below the gelatinization temperature. The specific procedure was as follows: 100 g of high amylose corn starch was mixed with 400 g of water until homogeneous, and then kept at its annealing temperature (80~85℃) for 24 h while heating and stirring. After heating, the starch was centrifuged at 8000 rpm for 10 min, the supernatant was discarded, and the precipitate was dried at 40℃.

[0059] The hydration characteristics of modified high amylose corn starch were analyzed, see... Figures 2-4 .

[0060] The results showed that after modification, the solubility and amylose leakage of the modified high-amylose corn starch were significantly improved, exceeding those of ungelatinized wheat flour (i.e., the solubility and mass starch leakage of wheat flour at 55-65℃), resulting in good hydration properties, but its swelling properties were not significantly altered. This indicates that even after cooking at 95℃, the modified high-amylose corn starch still maintains its intact starch granule structure, which is a prerequisite for maintaining good digestibility.

[0061] Its digestive characteristics were studied using an in vitro simulated digestion method, and the results are shown in […]. Figure 5 .

[0062] Figure 5 The results showed that the digestibility of modified high amylose corn starch was reduced, with the eGI value decreasing from 53.26 before modification to 50 / 26.

[0063] Performance testing and results analysis of dried noodle samples: The following performance tests were performed on the noodle samples prepared in Examples E1-E3 and Comparative Examples C1-C8 above: Processing performance evaluation: Record key phenomena during dough kneading and rolling to assess the processability of the dough.

[0064] Cooking quality: Refer to GB / T 40636-2021 "Noodles" to determine the cooking loss rate (%) and the rate of broken strands (%).

[0065] Texture properties (TPA test): The cooked noodles were analyzed using a physical property analyzer to determine the hardness (N), elasticity (ratio) and chewiness (mJ).

[0066] In vitro estimation of glycemic index (eGI): The hydrolysis index (HI) was calculated according to the in vitro simulated digestion method established by Goni et al., and the glycemic index of the sample was estimated by the formula eGI = 39.71 + 0.549 × HI.

[0067] Sensory evaluation: A sensory panel consisting of 7 trained evaluators will score the cooked noodles on color, appearance, elasticity, toughness, stickiness, and smoothness (on a scale of 1-9, with 9 being the best; see Table 1 for specific criteria) and calculate the total score.

[0068] Table 1 Sensory Evaluation Criteria for Noodles

[0069] The performance test results of the dried noodle samples are summarized in Table 2 below: Table 2: Summary of Performance Test Results of Noodle Samples

[0070] Note: The eGI values ​​for samples C1 and C3 were measured using materials that had been barely formed or dried and pulverized.

[0071] As shown in Table 2, Comparative Example C1 (using only modified starch): Although it had the lowest eGI value (48.0), indicating the strongest blood sugar lowering effect, it completely lost its processing properties and could not be made into qualified noodles. This shows that relying solely on modified starch cannot yield a usable product. Comparative Example C2 (using only composite structural base material): It had better processing properties and eating quality, but its eGI value was as high as 72.0, classifying it as a high-GI food and lacking blood sugar lowering function. In contrast, Example E1 of this invention: After introducing 30 parts of modified starch, the eGI value was significantly reduced to 52.6 (low-GI food), while maintaining excellent processability (easy to roll) and eating quality (sensory total score of 41.3, higher than C2's 35.4) through the support of the composite structural base material. This proves that the combination of modified starch and composite structural base material plays a key role in reducing the GI value, while the composite structural base material successfully "carries" the modified starch, ensuring its processability and final quality. The two work together to achieve the goal of "low GI and high quality" that cannot be achieved by a single component.

[0072] On the other hand, the E1 group samples were significantly better than C1 (which uses alkaline hydrothermal modified high amylose corn starch alone, as C1 cannot be shaped and will directly disintegrate during cooking, so it is considered to have extremely poor cooking performance) and C2 (which uses composite structural matrix alone) in terms of cooking performance (cooking loss rate and cooked breakage rate). This indicates that the alkaline hydrothermal modified high amylose corn starch and composite structural matrix of the present invention also have a synergistic effect in improving the cooking performance of noodles.

[0073] Comparative Example C3 (composite structural base material is only barley flour): Although the eGI value is low (54.2), the dough cannot form an effective network structure at all, is extremely loose, cannot be rolled into strips, and completely disintegrates after steaming or cooking. This indicates that barley flour alone cannot provide the necessary gluten and binding force to support the basic structure of the noodles. Comparative Example C4 (composite structural base material is only gluten): The dough is abnormally hard and elastic, but lacks extensibility, is difficult to roll, has a high breakage rate in the finished product, and has a hard and unpleasant texture, resulting in a very low sensory score (25.6). The eGI value (55.1) also does not meet the low GI standard. This indicates that although gluten alone can form strong gluten, the system is too dense, which is not conducive to the uniform dispersion and proper hydration of starch, resulting in unsatisfactory processability, eating quality, and GI reduction effect. Comparative Example C5 (composite structural base material is only wheat flour): The dough is processable, but the quality is average. The eGI value (68.0) is significantly higher than E1, and the sugar reduction effect is limited. This demonstrates that while wheat flour alone can guarantee basic processability and taste, it cannot provide the dietary fiber and glycemic index (GI)-lowering effect of barley flour, nor can it better "carry" the high proportion of modified starch through the fortification of gluten. This results in insufficient overall GI-lowering effect and textural support. Therefore, barley flour, gluten, and wheat flour constitute a complementary and indispensable synergistic system in this invention. Barley flour contributes dietary fiber and assists in GI lowering; gluten provides core gluten strength and strengthens the network to carry modified starch; wheat flour, as the matrix, regulates dough processability and provides flavor and basic gluten.

[0074] Furthermore, in terms of cooking performance, the E1 group samples significantly outperformed the C2, C3, C4, and C5 groups in terms of cooking performance (cooking loss rate and breakage rate) (C3 samples were considered to have extremely poor cooking performance because they could not form a solid structure and would disintegrate directly during cooking). This demonstrates that the synergistic effect of this invention in improving noodle cooking performance is achieved through the combined action of alkaline hydrothermal modified high amylose corn starch, barley flour, gluten, and wheat flour. The inventors believe this is because the components synergistically form a more stable composite gel network structure, which greatly limits the disintegration of starch granules and the dissolution of soluble substances during noodle cooking, thereby significantly reducing the cooking loss rate and breakage rate.

[0075] Comparative Example C6 (conventional hydrothermal modification): Its eGI value (60.0) is higher than E1 (48.5), and the processed dough is slightly coarser and of slightly inferior quality. This indicates that the "alkali method" treatment of the present invention can more effectively improve the starch processing adaptability while retaining or enhancing its anti-digestion properties compared to simple "hydrothermal" treatment. Comparative Example C7 (vegetable oil modification): Its eGI value (62.1) is much higher than E1, with poor sugar reduction effect, and it is too sticky and soft during processing. This indicates that different modification methods have a significant impact on the final behavior of starch in the noodle system. The alkali hydrothermal modification combined with alcohol precipitation method of the present invention is the preferred solution for the specific need of "low GI noodles", and its effect cannot be simply equivalent to or replaced by other common modification methods. It may be related to its better water and water properties, which makes it easier to polymerize with the composite structure matrix of the present invention to form a dense and uniform structure, thus slowing down the starch hydrolysis rate.

[0076] Comparative Example C8 (single-stage water addition): its cooking loss rate (9.8%) and cooked breakage rate (7.6%) were both higher than E1 (7.1%, 3.2%), and its sensory score was also lower (32.9 vs 41.3). This is because single-stage water addition makes it difficult to simultaneously and evenly hydrate the modified starch / barley flour and gluten / wheat flour, which have very different water absorption characteristics, easily leading to local clumping or uneven moisture distribution. The stepwise water addition process ensures that each component can be fully hydrated under suitable conditions, ultimately forming a more uniform and dense dough structure, thereby improving the product's cooking stability and taste. This proves that this process is a key step that complements the raw material system of this invention.

Claims

1. A type of low glycemic index dried noodles, characterized in that, The noodles are prepared from a raw material formula comprising the following parts by weight: 25-40 parts of alkaline hydrothermal modified high amylose corn starch, and 60-75 parts of composite structural base material; the composite structural base material is composed of highland barley flour, gluten flour and wheat flour in a mass ratio of (10-25):(15-25):(20-40); the noodles also contain edible salt comprising 0.1-0.3 parts by weight of the raw material formula.

2. The low glycemic index noodles according to claim 1, characterized in that: The raw material formula also includes mixed grain powder, which accounts for 1% to 30% of the mass of the raw material formula, and the mixed grain powder includes oat flour and / or buckwheat flour.

3. The low glycemic index noodles according to claim 1, characterized in that, The preparation method of the alkaline hydrothermal modified high amylose corn starch includes the following steps: mixing high amylose corn starch with an amylose content ≥50% with a sodium carbonate solution of 2% to 4% by mass, wherein the mass ratio of starch to sodium carbonate solution is 1:(2.5 to 4), heating and stirring at 80℃ to 95℃ for 4 to 8 hours, then homogenizing, and then adding ethanol with a volume concentration of 93% to 98% for precipitation, wherein the volume ratio of ethanol to starch milk is 1:1 to 1.5:1, stirring evenly, standing, centrifuging, washing, and drying to obtain the alkaline hydrothermal modified high amylose corn starch.

4. The low glycemic index noodles according to any one of claims 1 to 3, characterized in that, The barley flour is whole barley flour with a β-glucan content ≥5%; the gluten flour has a protein content ≥75%; and the wheat flour is high-gluten wheat flour with a wet gluten content ≥30%.

5. A method for preparing low glycemic index noodles as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Raw material preparation: Weigh each raw material according to the raw material formula; S2. First mixing: Mix the wheat gluten with the wheat flour, add the first portion of water, and stir for 5-8 minutes to obtain mixture 1; the amount of the first portion of water added is 15%-25% of the total mass of the wheat gluten and wheat flour; S3. Second mixing: Mix the alkaline hydrothermal modified high amylose corn starch, the highland barley flour, and the optional miscellaneous grain flour. Dissolve the edible salt in the second part of water, add the salt water to the powder mixture, and stir for 8-10 minutes to obtain mixture 2. The amount of the second part of water added is 25%-45% of the total mass of the alkaline hydrothermal modified high amylose corn starch, highland barley flour, and optional miscellaneous grain flour. S4. Final mixing and dough resting: Combine the mixture 1 and the mixture 2, stir and mix for 5-8 minutes to obtain the final mixture, and then let the dough rest. S5. Rolling and cutting: The final mixture after the dough has rested is rolled into a sheet with a thickness of 1-3 mm using a rolling mill, and then cut into strips to obtain wet noodles; S6. Drying: Dry the wet noodles at 35℃~45℃ for 6~10 hours to obtain the low glycemic index noodles.

6. The method according to claim 5, characterized in that, The conditions for proofing the dough in step S4 are: let it stand for 15 to 30 minutes at 25℃~30℃ and relative humidity of 75%~85%.

7. The use of a low glycemic index noodle as described in any one of claims 1 to 4 in the preparation of foods for which postprandial blood glucose levels need to be controlled.

8. A blood sugar control food composition, characterized in that, Includes the low glycemic index noodles as described in any one of claims 1 to 4.

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