Preparation method of low-GI rice flour and low-GI rice flour

Abstract

The invention relates to a preparation method of low-GI rice noodles and the low-GI rice noodles, and the method comprises the following steps: mixing rice flour, corn starch and sweet potato powder in proportion to obtain mixed powder; adding water into the mixed powder, stirring, and carrying out hydration treatment to obtain compound milk; sequentially gelatinizing, extruding and forming the compound milk to obtain fresh wet rice noodles; sequentially aging and drying the fresh and wet rice noodles to obtain the low-GI rice noodles. The GI value of the finished rice flour is reduced by adding the southern potato flour into the rice flour, meanwhile, the taste of the rice flour can be improved by adding the southern potato flour, the gel strength of the rice flour is remarkably improved, the breaking rate of the rice flour is reduced, the rice flour is smoother and easy to digest, and the problems that existing rice flour is high in GI value and poor in taste flexibility are effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a preparation method of low GI rice flour and the low GI rice flour. Background Art

[0002] Rice noodle products are the traditional staple food of residents in southern my country. They contain various nutrients necessary for the human body, such as carbohydrates, proteins, lipids, vitamins and minerals. At present, common rice noodles are mainly thin or wide flat rice products processed from rice as raw materials, and the processing steps mainly include washing, soaking, crushing or grinding, gelatinization, extruding or cutting. As a whole, they occupy a large share in the rice product market and are one of the most popular rice products at present.

[0003] With the accelerated pace of life and the improvement of consumers' health awareness, modern people's demand for food nutrition and health has also increased. However, most traditional instant rice noodles are high-GI foods (GI value>70). They are quickly digested and release glucose quickly after entering the gastrointestinal tract, which can easily cause blood sugar fluctuations, increase the risk of chronic diseases including diabetes, and affect health. In addition, the taste of traditional instant rice noodles is not as flexible as fresh wet rice noodles, and the rehydration effect is poor.

[0004] Therefore, it is an urgent problem to be solved to provide a method for preparing low GI (GI value ≤ 55) rice noodles so that the prepared rice noodles can meet the health needs of food while improving the taste of the rice noodles. Summary of the invention

[0005] In view of this, the main purpose of the present invention is to provide a preparation method of low GI rice noodles and low GI rice noodles, by adding southern potato flour to rice flour to reduce the GI value of the finished rice noodles, while the addition of southern potato flour can also improve the taste of the rice noodles, significantly improve the gel strength of the rice noodles, make them smoother and easier to digest, and effectively solve the problem that the existing rice noodles have a high GI value and poor taste flexibility.

[0006] In a first aspect, the present invention provides a method for preparing low GI rice flour, comprising the following steps:

[0007] Mix rice flour, corn starch and yam flour according to proportion to obtain mixed flour;

[0008] Adding water to the mixed powder, stirring, and performing hydration treatment to obtain a compound milk;

[0009] The compound milk is gelatinized, extruded and molded in sequence to obtain fresh wet rice noodles;

[0010] The fresh wet rice noodles are aged and dried in sequence to obtain low GI rice noodles.

[0011] In some embodiments, the ratio of each component in the mixed powder is:

[0012] Rice flour 74.07%, corn starch 22.22% and sweet potato flour 3.70%.

[0013] In some embodiments, the raw material of the rice flour is rice with an amylose content of 20%-30%; and

[0014] The preparation process of the rice flour comprises:

[0015] Soak the washed rice in clean water for 20-30 minutes;

[0016] Drain the soaked rice, spread it flat on a drying tray, dry it in an electric constant temperature air drying oven under the blowing mode, and cool it after drying to constant weight;

[0017] The cooled rice is crushed in turn and sieved through 120 meshes to obtain rice flour for later use.

[0018] In some embodiments, the preparation process of the southern potato flour includes:

[0019] Place the washed sweet potatoes in a grinding cylinder and use the protrusions of the grinding cylinder to grind the sweet potatoes into puree;

[0020] Put the sweet potato puree on the filter, rub it back and forth in running water, and dry and sieve the sediment at the bottom of the tank through 100 mesh to obtain the sweet potato powder for later use.

[0021] In some embodiments, when the mixed powder is added with water and stirred, the stirring speed is 150-300 r / min and the stirring time is 10-20 min.

[0022] In some of the embodiments, during the hydration treatment, the mixture of the mixed powder and water is placed at room temperature to balance the moisture for 0.5 h, and the compound milk is fully hydrated to obtain the compound milk; and the water content of the compound milk is 51%.

[0023] In some of the embodiments, the gelatinization, extrusion and molding of the compound milk are carried out in sequence based on a twin-screw rice noodle extrusion machine, and the die aperture of the twin-screw rice noodle extrusion machine is 1 mm.

[0024] In some embodiments, when the fresh wet rice noodles are aged and dried in sequence:

[0025] The aging temperature is 4°C and the aging time is 6h;

[0026] The drying temperature is 50-60℃ and the drying time is 6-8h.

[0027] In some embodiments, the water content of the low GI rice flour is ≤13%.

[0028] In a second aspect, the present application provides a low GI rice flour, comprising the following components in weight ratio:

[0029] Water ≤ 13%, the rest is mixed powder;

[0030] Wherein, the proportion of each component in the mixed powder is:

[0031] Rice flour 74.07%, corn starch 22.22% and sweet potato flour 3.70%.

[0032] Technical effects of the present invention:

[0033] The present invention reduces the glycemic index, i.e., the GI value, of rice noodles by optimizing the raw material formula and the processing technology. Specifically, by adding yam flour to the raw materials, the gel strength of the rice noodles is significantly improved, and the GI value can be reduced while reducing the breakage rate of the rice noodles. Because yam flour has strong viscosity and low gelatinization temperature, it can quickly form a gel with uniform texture at low temperature, which helps to enhance the feeling of fullness. Therefore, the rice noodles prepared in this way are not easy to break during the steaming process, and have a white and bright appearance, a flexible texture, are easy to digest, do not become mushy when boiled in water, have a good rice fragrance and taste, and are suitable for the dietary needs of consumers.

[0034] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

[0036] Figure 1 The figure shows a schematic flow chart of a method for preparing low GI rice flour according to an embodiment of the present application;

[0037] Figure 2 A schematic diagram showing the gel strength of dry rice flour prepared according to different recipes of the examples of the present application. DETAILED DESCRIPTION

[0038] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0039] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0040] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0041] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0042] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0043] like Figure 1 As shown, the present invention provides a method for preparing low GI rice flour, comprising the following steps:

[0044] S100, mixing rice flour, corn starch and yam flour according to proportion to obtain mixed flour;

[0045] In this step, by adding yam flour and corn starch to rice flour, low GI rice flour is prepared. It should be noted that the tubers of yam are rich in starch, and after processing, yam flour containing soluble dietary fiber, protein, vitamins and carbohydrates can be made. Among them, after the yam flour is subjected to extrusion aging treatment, the resistant starch produced can effectively reduce the GI value of rice flour and meet the health needs of food.

[0046] Specifically, in this step, preferably, rice flour, corn starch and yam flour are uniformly mixed in a ratio of 74.07% rice flour, 22.22% corn starch and 3.70% yam flour to obtain mixed flour. Among them, by adding 3.70% yam flour, the gel strength of rice flour can be enhanced, and the enhancement of gel strength can slow down the blood sugar rise rate of rice flour and prevent strong fluctuations in blood sugar after consumption. At the same time, 22.22% corn starch is also added to further improve the breaking force and gel strength of rice flour on this basis.

[0047] It should be noted that the synergistic effect of corn starch and yam flour forms a cross-linked structure between starch molecules, thereby enhancing the toughness of rice noodles. When 22.22% corn starch and 3.70% yam flour are added, the rice noodles have stronger toughness and elasticity and a better taste.

[0048] Moreover, the raw material of the rice flour in this step is preferably rice with an amylose content of 20%-30%. In addition, in the process of preparing the rice flour, the rice with an amylose content of 20-30% is cleaned and soaked in clean water for 20-30 minutes. The soaked rice is drained of water, spread on a drying tray, and an electric constant temperature blast drying oven is used to turn on the blast mode, and the rice is dried to a constant mass in the blast mode, and then taken out and cooled. The cooled rice is poured into a high-speed multifunctional grinder for pulverization, and passed through a 120-mesh sieve for standby use.

[0049] It should also be noted that in the process of preparing yam flour, fresh yam is washed and placed in a grinding cylinder, and the yam is ground back and forth along the convex points of the grinding cylinder to make it into mud. Subsequently, the yam mud is placed on a filter screen and rubbed back and forth in running water. The starch precipitated at the bottom of the cylinder is yam flour. The precipitate is dried and passed through a 100-mesh sieve for later use.

[0050] S200, adding water to the mixed powder, stirring, and performing hydration treatment to obtain a compound milk;

[0051] In this step, water is added to the mixed powder obtained in step S100, and stirred evenly, and the water content of the mixed powder needs to be ensured to reach 51%, so as to obtain a fully hydrated composite milk. The mixing and stirring of the mixed powder and water in this step is achieved based on a mixer, and the stirring speed is preferably 150-300r / min, and the stirring time is preferably 10-20min, so that the two can be mixed evenly. In addition, the full hydration of the two in this step is achieved by mixing the two and placing them at room temperature for 0.5h to balance the water content.

[0052] It should be noted that by fully mixing the mixed flour with water, the starch granules in the rice noodles can fully absorb water and swell. In the subsequent processing, the starch granules can be better gelatinized, making the taste of the finished rice noodles more delicate and smooth. At the same time, it also helps the protein and starch and other ingredients in the rice noodles to interact with each other, which is more conducive to the subsequent mixing and molding, and also enhances the toughness and strength of the rice noodles, reduces the breakage rate, and improves the integrity of the rice noodles. In particular, it should be noted that the addition of southern potato flour enables the rice noodles to significantly improve their own gel strength without using any colloidal substances, making the internal structure of the rice noodles more compact, which helps to enhance the sense of fullness.

[0053] S300, sequentially gelatinizing, extruding, and molding the compound milk to obtain fresh wet rice noodles;

[0054] In this step, the balanced compound milk in step S200 is transferred to a rice noodle machine for gelatinization, extrusion, and molding, thereby obtaining fresh wet rice noodles. Wherein, the rice noodle machine is preferably a twin-screw extrusion rice noodle machine, and the grinding diameter of the rice noodle machine mold is preferably 1mm. By gelatinizing the compound milk, the internal structure of the starch granules therein is changed, and the ordered crystalline structure is transformed into a disordered amorphous structure, so that the starch has viscosity and plasticity, which helps to reduce the GI value while improving the mouthfeel of the rice noodles. Further, the compound milk after gelatinization has certain fluidity and plasticity. Under the action of the twin-screw extrusion rice noodle machine, the compound milk is extruded and molded under pressure through a molding die with a grinding diameter of 1mm to obtain fresh wet rice noodles.

[0055] S400, aging and drying the fresh wet rice noodles in sequence to obtain low GI rice noodles.

[0056] In this step, the fresh wet rice noodles after extrusion molding in step S300 are aged at 4° C. for 6 hours, and then dried. When the final moisture content is measured to be below 13%, a low GI dry rice noodle product is obtained. When the aged fresh wet rice noodles are dried, the drying temperature is preferably 50-60° C., and the drying time is preferably 6-8 hours, that is, low-temperature blast drying is performed at 50-60° C. for 6-8 hours to obtain a finished low GI rice noodle. It should be noted that the GI value of the finished dry rice noodle is 50.62, which meets the requirements of low GI (GI value ≤ 55) food.

[0057] Correspondingly, the present invention also provides low GI rice flour prepared by the above-mentioned preparation method, comprising the following weight ratio components: water ≤13%, and the balance is mixed powder; wherein the proportions of the components in the mixed powder are: rice powder 74.07%, corn starch 22.22% and southern potato powder 3.70%.

[0058] It can be seen that the present invention reduces the glycemic index, i.e., the GI value, of rice noodles by optimizing the raw material formula and processing technology. Specifically, by adding yam flour to the raw materials, the gel strength of the rice noodles is significantly improved, and the GI value can be reduced while reducing the breakage rate of the rice noodles. Because yam flour has strong viscosity and low gelatinization temperature, it can quickly form a gel with uniform texture at low temperature, which helps to enhance the feeling of fullness. Therefore, the rice noodles prepared in this way are not easy to break during the cooking process, and the appearance is white and bright, the texture is flexible, easy to digest, and the soup does not become mushy when boiled in water. It has a good rice fragrance and taste, and is suitable for the dietary needs of consumers.

[0059] The present invention will be further described below with reference to specific embodiments.

[0060] Example 1

[0061] A method for preparing low GI rice flour comprises the following steps:

[0062] (1) selecting rice with an amylose content of 20-30% as a raw material, washing it clean, and soaking it in clean water for 20-30 minutes, draining the soaked rice, spreading it flat on a drying plate, using an electric constant temperature air drying oven to start the air blowing mode, setting the temperature to 50° C., drying the rice to a constant weight and then cooling it; pouring the dried and cooled rice into a high-speed multifunctional pulverizer for pulverization, and passing the pulverized rice powder through a 120-mesh sieve for standby use;

[0063] (2) Wash fresh sweet potatoes, put them in a grinding cylinder, grind them into mud along the convex points of the grinding cylinder, put the muddled sweet potatoes on a filter screen, rub them back and forth in running water, and the starch precipitated at the bottom of the cylinder is sweet potato flour. Dry the precipitate and pass it through a 100-mesh sieve for later use;

[0064] (3) Accurately weigh 500 g of rice flour, 150 g of corn starch and 25 g of yam flour into a stainless steel basin, stir evenly, then add 702.55 g of water to fully hydrate the rice slurry, and the final moisture content of the rice slurry reaches 51%. The rice slurry is then extruded into a rice noodle machine, and the die aperture of the rice noodle machine is 1 mm; the extruded rice noodles are aged at 4° C. for 6 h; the aged rice noodles are placed in an oven at 50-60° C. for hot air drying for 6-8 h, and the moisture content is measured to be below 13%, and the rice noodles are put into a ziplock bag for standby use.

[0065] Comparative Example 1

[0066] A method for preparing low GI rice flour, which is different from Example 1 in that the addition ratio of rice flour, corn starch and yam flour and the amount of water used during hydration treatment are changed, specifically:

[0067] Weigh 500g of rice flour, 150g of corn starch and 35g of sweet potato flour into a stainless steel bowl, stir evenly and add 712.96g of water to fully hydrate them.

[0068] Comparative Example 2

[0069] A method for preparing low GI rice flour, which is different from Example 1 in that only rice flour and corn starch are added, and no southern potato flour is added, and the amount of water used in the hydration treatment is also different, specifically:

[0070] Weigh 500g of rice flour and 150g of corn starch into a stainless steel bowl, stir evenly and add 704.17g of water to fully hydrate them.

[0071] Comparative Example 3

[0072] A method for preparing low GI rice flour, which is different from Example 1 in that only rice flour and southern potato flour are added, no corn starch is added, and the amount of water used in the hydration treatment is also different, specifically:

[0073] Weigh 500g of rice flour and 25g of sweet potato flour into a stainless steel bowl, stir evenly, and then add 546.43g of water to fully hydrate them.

[0074] The comparison results of the dried rice noodles prepared in Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 are shown in Tables 1-4 and Figure 2 shown.

[0075] Specifically, Table 1 shows the gel properties of dried rice flour prepared with different recipes. Figure 2 The schematic diagram of gel strength of dried rice flour prepared for different recipes is shown in Table 1 and Figure 2 It can be seen that different ingredients have different effects on the gel strength of finished rice noodles. Among them, the breaking force and gel strength corresponding to rice noodles without southern potato flour are significantly lower than those with southern potato flour, that is, the addition of southern potato flour can enhance the gel strength of rice noodles. However, if only southern potato flour is added without corn starch, although the breaking force and gel strength of rice noodles can be enhanced, there is still a large gap between the rice noodles with southern potato flour and corn starch added at the same time. Therefore, the combined effect of corn starch and southern potato flour is the key to improving the gel strength of rice noodles. At the same time, compared with adding 21.90% corn starch and 5.11% southern potato flour, the gel strength is stronger when adding 22.22% corn starch and 3.70% southern potato flour, that is, the rice noodles with 3.70% southern potato flour can show the best gel strength, the lowest breaking rate, the highest toughness, and a better taste after steaming.

[0076]

[0077] Table 1 Gel performance test table of dry rice flour prepared with different formulas

[0078] Further, Table 2 shows a table of physical and chemical characteristics of dry rice noodles prepared with different recipes. Among them, the water absorption rate characterizes the water absorption capacity of dry rice noodles during the soaking process. As can be seen from Table 2, the light transmittance of dry rice noodles with added nanshu powder is significantly higher than that of dry rice noodles without added nanshu powder. Among them, the light transmittance of rice noodles with added 21.90% corn starch and 5.11% nanshu powder is the highest, reaching 94.20%; at the same time, the water absorption rate of dry rice noodles with added corn starch and nanshu powder is significantly lower than that of dry rice noodles without added nanshu powder or only added nanshu powder. In addition, the water absorption rate of rice noodles with added 22.22% corn starch and 3.70% nanshu powder is the lowest, which is 109.34%. The reason is that the addition of nanshu powder allows starch molecules to form a dense and stable structure during the gelatinization process, inhibiting the absorption of water, thereby reducing the water absorption rate.

[0079] The cooking loss reflects the amount of solid loss of dry rice noodles during the soaking process, which can reflect the ability of rice noodles to maintain structural integrity during hot water cooking. Lower cooking loss means lower quality loss and higher nutrient retention rate. As shown in Table 2, the cooking loss of dry rice noodles with added nanshu flour is significantly lower than that of dry rice noodles without nanshu flour, indicating that the addition of nanshu flour promotes the formation of a strong gel network structure between starch molecules, which helps to maintain the quality of rice noodles. In addition, the rice noodles with added nanshu flour also showed significant improvement in the breaking rate. When 22.22% corn starch and 3.70% nanshu flour were added, the breaking rate was the lowest, at 4.93%. This result shows that the synergistic effect of corn starch and nanshu flour forms a cross-linked structure between starch molecules, thereby increasing the toughness of rice noodles. However, when the amount of nanshu flour added gradually increases, the cross-linked structure is further enhanced, resulting in an increase in the hardness of the rice noodles, but a decrease in elasticity and toughness. When 5.11% nanshu flour was added, the breaking rate increased significantly, and the guarantee of rice noodles quality was not as strong as 3.70% nanshu flour.

[0080] It should be noted that the ideal rice flour should have higher water absorption and light transmittance, lower breaking rate and cooking loss. Therefore, based on the analysis of the above index determination, the dry rice flour prepared by adding 22.22% corn starch and 3.70% yam flour in Example 1 has better comprehensive performance.

[0081]

[0082]

[0083] Table 2 Physical and chemical characteristics of dried rice flour prepared with different formulas

[0084] Furthermore, texture is an important quality index of dried rice noodles, among which higher hardness and good elasticity are the key characteristics of ideal dried rice noodles, which can improve their chewiness. Table 3 shows the texture characteristics measurement table of dried rice noodles prepared for different recipes. It can be seen from Table 3 that the hardness of dried rice noodles with added yam flour is significantly higher than that of dried rice noodles without added yam flour. Among them, the amount of yam flour added reaches 5.11%, and the hardness value is the largest, which is also the reason for the higher breaking rate of rice noodles in comparative example 1. When the amount of yam flour added is 3.70%, the hardness of the rice noodles is still large, and the elasticity (0.82) and chewiness (550.20) of the rice noodles under this condition are the highest in each group, and the adhesiveness is 670.29. The reason is that yam flour itself has strong gel strength and viscosity, and when used in combination with corn starch, due to the interaction of amylose, the ability of amylose molecules to rearrange and migrate during gelatinization is enhanced. The higher the content of amylose, the more intense the entanglement and cross-linking between molecules, and the tighter the gel structure formed. However, when the addition of nanshu flour increased to 5.11%, the elasticity and chewiness of rice flour decreased. This may be because the excessive starch cross-linking was too tight, causing the starch molecules to absorb water excessively and swell, occupying a large amount of space, thus affecting the formation of the gel structure. In addition, some studies have shown that the elasticity and chewiness of the gel first increased and then decreased, which may be related to the changes in the degree of starch hydrolysis and the characteristics of the aggregated particles during the gel formation process.

[0085] In summary, judging from the texture data, dry rice noodles can show the optimal hardness, elasticity and chewiness under the compound conditions of adding 22.22% corn starch and 3.70% southern potato flour, and have the most ideal texture characteristics.

[0086]

[0087] Table 3 Texture characteristics of dry rice flour prepared with different recipes

[0088] After the dried rice noodles were cooked, a sample amount equivalent to 50 mg of carbohydrates was weighed, and in vitro simulated digestion was performed according to professional experiments to determine the starch hydrolysis rate. Glucose was used as a standard to make a standard curve, and the glucose content during the digestion process was determined by the DNS method. The contents of rapidly digestible starch RDS, slowly digestible starch SDS and resistant starch RS were calculated according to the following formula.

[0089] Starch hydrolysis rate (%) = (glucose equivalent at sampling point / total starch content) * 100

[0090] RDS=[(G20-G0)*0.9] / TS*100%

[0091] SDS=[(G120-G20)*0.9] / TS*100%

[0092] RS=[TS-(RDS+SDS) / TS*100%

[0093] Where: G0, G20, G120 represent the glucose content produced at 0, 20, and 120 min of hydrolysis, mg; TS represents the total starch content in the sample, mg;

[0094] For the calculation of GI, a hydrolysis curve was drawn (with time as the horizontal axis and starch hydrolysis rate as the vertical axis), the area under the curve (AUC) was calculated, and the starch hydrolysis index (HI) was calculated according to the following formula, thereby calculating the in vitro GI. The specific results are shown in Table 4.

[0095] HI (%) = AUC sample / AUC (white bread) * 100

[0096] GI = 0.862HI + 8.1981;

[0097]

[0098] Table 4 GI determination table of dry rice flour prepared with different recipes

[0099] In summary, the present invention provides a dry rice flour without adding any colloid, which is made by mixing 74.07% rice flour, 22.22% corn starch and 3.70% yam flour. The prepared finished rice flour has a low GI value (eGI value is 50.62), and significantly reduces the content of rapidly digestible starch RDS by increasing the content of resistant starch RS and soluble starch SDS, thereby slowing down the release rate of glucose and enhancing digestibility. The addition of yam flour not only improves the gel texture of the rice flour, but also has the effect of absorbing glucose, meeting the needs of contemporary consumers for healthy diet.

[0100] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0101] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "one", "the" and the like involved in this application do not indicate a quantitative limitation and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in this application are intended to cover non-exclusive inclusions. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to two or more, and "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. The terms "first", "second", "third" and the like involved in this application are merely to distinguish similar objects and do not represent a specific ordering of objects.

[0102] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but the limitation of the scope of the invention patent cannot be understood as a result. It should be pointed out that, for a person of ordinary skill in the art, several variations or improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for preparing low GI rice flour, characterized in that: The steps include: Mix rice flour, corn starch and yam flour according to proportion to obtain mixed flour; Adding water to the mixed powder, stirring, and performing hydration treatment to obtain a compound milk; The compound milk is gelatinized, extruded and molded in sequence to obtain fresh wet rice noodles; The fresh wet rice noodles are aged and dried in sequence to obtain low GI rice noodles.

2. The method for preparing low GI rice flour according to claim 1, wherein The proportions of the components in the mixed powder are: Rice flour 74.07%, corn starch 22.22% and sweet potato flour 3.70%.

3. The method for preparing low GI rice flour according to claim 1, wherein The raw material of the rice flour is rice with an amylose content of 20%-30%; and The preparation process of the rice flour comprises: Soak the washed rice in clean water for 20-30 minutes; Drain the soaked rice, spread it flat on a drying tray, dry it in an electric constant temperature air drying oven under the blowing mode, and cool it after drying to constant weight; The cooled rice is crushed in turn and sieved through 120 meshes to obtain rice flour for later use.

4. The method for preparing low GI rice flour according to claim 1, wherein The preparation process of the southern potato flour comprises: Place the washed sweet potatoes in a grinding cylinder and use the protrusions of the grinding cylinder to grind the sweet potatoes into puree; Put the sweet potato puree on the filter, rub it back and forth in running water, and dry and sieve the sediment at the bottom of the tank through 100 mesh to obtain the sweet potato powder for later use.

5. The method for preparing low GI rice flour according to claim 1, characterized in that When the mixed powder is added with water and stirred, the stirring speed is 150-300 r / min and the stirring time is 10-20 min.

6. The method for preparing low GI rice flour according to claim 1, characterized in that During the hydration treatment, the mixture of the mixed powder and water was placed at room temperature to balance the moisture for 0.5 h, and the compound milk was obtained after sufficient hydration; and the water content of the compound milk was 51%.

7. The method for preparing low GI rice flour according to claim 1, characterized in that The compound milk is sequentially gelatinized, extruded and molded based on a twin-screw rice noodle extruder, and the die aperture of the twin-screw rice noodle extruder is 1 mm.

8. The method for preparing low GI rice flour according to claim 1, characterized in that When the fresh wet rice noodles are aged and dried in sequence: The aging temperature is 4°C and the aging time is 6h; The drying temperature is 50-60℃ and the drying time is 6-8h.

9. The method for preparing low GI rice flour according to claim 8, characterized in that The water content of the low GI rice flour is ≤13%.

10. A low GI rice flour, characterized in that The composition includes the following weight ratio: Water ≤ 13%, the rest is mixed powder; Wherein, the proportion of each component in the mixed powder is: Rice flour 74.07%, corn starch 22.22% and sweet potato flour 3.70%.

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