Multi-cereal flour with low glycemic index and application thereof

Abstract

The invention provides multi-cereal flour with a low glycemic index and application of the multi-cereal flour, and belongs to the technical field of food processing. The multi-cereal flour comprises the following raw materials in parts by mass: 20-30 parts of wheat flour, 5-10 parts of buckwheat flour, 3-5 parts of oat flour, 5-10 parts of corn starch, 5-10 parts of highland barley flour, 5-10 parts of oat dietary fiber flour, 5-10 parts of vital gluten, 5-10 parts of wheat dietary fiber flour, 3-5 parts of rye flour, 3-5 parts of tartary buckwheat flour, 3-5 parts of quinoa flour and 3-5 parts of coix seed flour. The invention provides the multi-cereal flour which takes the high-amylose wheat and various coarse cereals as the main raw materials, and the flour product prepared from the multi-cereal flour can reduce the starch hydrolysis rate by inhibiting the enzyme activity of amylase and glucose hydrolysis enzymes, so that the postprandial blood sugar rising rate is delayed.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and particularly relates to a multi-grain flour with a low glycemic index and its application. Background Art

[0002] In today's society, the pace of people's lives is generally getting faster and faster, and the number of sub-healthy people is increasing, resulting in a significant increase in the proportion of obese people, diabetic patients, and people with high blood sugar. At present, diabetes cannot be completely cured, and mainly relies on drug treatment supplemented by dietary treatment means. More and more people are starting to pay attention to a healthy diet while solving three meals a day, hoping that food not only meets nutritional supply, but also performs well in terms of health effects, taste preferences, etc. Solving the eating problem of "people with high blood sugar" is of great significance for ensuring life health and conforming to the health strategy.

[0003] The degree of digestion, absorption of food by the human body and the resulting blood glucose response are expressed by the glycemic index (GI). Foods with a lower GI are digested and absorbed slowly in the body, which helps to maintain stable postprandial blood glucose and has better advantages in preventing and controlling diabetes. A scientific and reasonable diet is the key to preventing and controlling diabetes. Research shows that components in food such as protein, lipid, dietary fiber, polyphenol, polypeptide, etc. can regulate the blood glucose level of the body through different mechanisms of action. Ordinary noodles made from wheat flour have a high starch content, and the degree of starch gelatinization is high during the production process. After being absorbed by the gastrointestinal tract, the blood glucose in the body rises rapidly, and its GI value is 81.6. Due to reasons such as insulin secretion and action disorders, and disorders of glycogen synthesis and release in the liver in diabetic patients, the body's glucose metabolism is disordered. Coarse grains have good physiological functions and play an important role in reducing fat, lowering postprandial blood glucose levels, preventing cardiovascular and cerebrovascular diseases, etc., and are commonly used as raw materials for low-GI foods.

[0004] High amylose wheat is a high-quality raw material for preparing low glycemic index / low-GI foods. The digestion characteristics of starch are related to the amylose content. Amylose molecules are intertwined with each other to form a three-dimensional gel network, and this gel network structure will increase the resistance of starch to enzymes and delay starch digestion. Therefore, how to make full use of grain resources, achieve a healthy combination, and develop healthy multi-grain flour and its low-GI flour products while retaining the good taste of traditional wheat flour products is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-grain flour with a low glycemic index and its application.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a multi-grain flour with a low glycemic index, comprising raw materials in the following parts by mass: 20-30 parts of wheat flour, 5-10 parts of buckwheat flour, 3-5 parts of oat flour, 5-10 parts of corn starch, 5-10 parts of highland barley flour, 5-10 parts of oat dietary fiber powder, 5-10 parts of vital wheat gluten, 5-10 parts of wheat dietary fiber powder, 3-5 parts of rye flour, 3-5 parts of tartary buckwheat flour, 3-5 parts of quinoa flour, and 3-5 parts of coix seed powder.

[0008] Preferably, the wheat flour is wheat flour with a straight-chain starch content of ≥30%.

[0009] The present invention provides a preparation method of the multi-grain flour, comprising mixing raw materials in formula amounts to obtain the multi-grain flour.

[0010] Preferably, all raw materials are sieved through a 80-120 mesh sieve before mixing; after sieving, the buckwheat flour, oat flour, highland barley flour, tartary buckwheat flour, quinoa flour, and coix seed powder are further subjected to ultrafine grinding, and the pressure of the ultrafine grinding is 0.75-0.85 MPa, and the sorting frequency is 32-40 Hz.

[0011] The present invention provides an application of the multi-grain flour or the multi-grain flour prepared according to the method in the preparation of foods with a low glycemic index.

[0012] Preferably, the foods include noodles and biscuits.

[0013] The present invention provides a preparation method of low-glycemic-index hanging noodles, comprising the following steps:

[0014] (1) Mixing the multi-grain flour or the multi-grain flour prepared according to the method with water to obtain a multi-grain dough;

[0015] (2) Pressing, cutting, and drying the multi-grain dough obtained in step (1) to obtain low-glycemic-index hanging noodles.

[0016] Preferably, the thickness of the pressing is 0.4-1.2 mm, and the number of pressing times is 8-12 times.

[0017] Preferably, the drying includes first drying, second drying, and third drying carried out in sequence;

[0018] The temperature of the first drying is 30-35°C, the humidity is 80-90%, and the time is 60-90 min;

[0019] The temperature of the second drying is 40-45°C, the humidity is 70-80%, and the time is 120-150 min;

[0020] The temperature of the third drying is 30-35°C, the humidity is 60-70%, and the time is 60-90 min.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a multi-grain flour mainly made of high amylose wheat and various miscellaneous grains. The flour products made from the multi-grain flour can inhibit the enzyme activities of amylase and glucose-hydrolyzing enzymes, reduce the starch hydrolysis rate, and thus delay the rising rate of postprandial blood glucose.

[0023] When preparing the multi-grain flour, the sieved buckwheat flour, oat flour, highland barley flour, tartary buckwheat flour, quinoa flour, and coix seed powder are further pulverized by a pneumatic ultrafine pulverizer, so as to achieve the purpose of not generating a rough feeling and improving palatability after being added to food. The dosage of the miscellaneous grain flour is controlled within a suitable range, which can ensure better taste of the food while taking into account the nutritional value and blood sugar-lowering effect.

[0024] The present invention also prepares the multi-grain flour into noodles with a low glycemic index. The pGI value of the noodles is 48.3-53.0, which is much lower than that of the noodles prepared from wheat flour and water, and is especially suitable for people with health needs. Detailed implementation mode

[0025] The present invention provides a multi-grain flour with a low glycemic index, comprising the following raw materials in parts by mass: 20-30 parts of wheat flour, 5-10 parts of buckwheat flour, 3-5 parts of oat flour, 5-10 parts of corn starch, 5-10 parts of highland barley flour, 5-10 parts of oat dietary fiber powder, 5-10 parts of gluten powder, 5-10 parts of wheat dietary fiber powder, 3-5 parts of rye flour, 3-5 parts of tartary buckwheat flour, 3-5 parts of quinoa flour, and 3-5 parts of coix seed powder.

[0026] In the present invention, the multi-grain flour preferably comprises the following raw materials in parts by mass: 22-28 parts of wheat flour, 7-9 parts of buckwheat flour, 3-5 parts of oat flour, 7-9 parts of corn starch, 7-9 parts of highland barley flour, 7-9 parts of oat dietary fiber powder, 7-9 parts of gluten powder, 7-9 parts of wheat dietary fiber powder, 3-5 parts of rye flour, 3-5 parts of tartary buckwheat flour, 3-5 parts of quinoa flour, and 3-5 parts of coix seed powder. More preferably, it comprises the following raw materials in parts by mass: 25 parts of wheat flour, 8 parts of buckwheat flour, 4 parts of oat flour, 8 parts of corn starch, 8 parts of highland barley flour, 8 parts of oat dietary fiber powder, 8 parts of gluten powder, 8 parts of wheat dietary fiber powder, 4 parts of rye flour, 4 parts of tartary buckwheat flour, 4 parts of quinoa flour, and 4 parts of coix seed powder.

[0027] In the present invention, the wheat flour is wheat flour with a straight-chain starch content of ≥30%, preferably wheat flour made from Lunxuan 49.

[0028] The present invention provides a method for preparing the multi-grain flour, which comprises mixing the raw materials in formula amounts to obtain the multi-grain flour.

[0029] In the present invention, before mixing, all the raw materials are sieved through a 80-120 mesh sieve, preferably through a 90-115 mesh sieve, and more preferably through a 100 mesh sieve; after sieving, the buckwheat flour, oat flour, hulless barley flour, tartary buckwheat flour, quinoa flour and coix seed powder are further subjected to ultrafine grinding. The pressure of the ultrafine grinding is 0.75-0.85 MPa, preferably 0.8 MPa, the sorting frequency is 32-40 Hz, preferably 34-38 Hz, more preferably 35-37 Hz, and even more preferably 36 Hz.

[0030] The present invention provides an application of the multi-grain flour or the multi-grain flour prepared according to the method in the preparation of foods with a low glycemic index.

[0031] In the present invention, the foods include noodles and biscuits.

[0032] The present invention provides a method for preparing a low-glycemic-index hanging noodle, which comprises the following steps:

[0033] (1) Mixing the multi-grain flour or the multi-grain flour prepared according to the method with water to obtain a multi-grain dough;

[0034] (2) Pressing the multi-grain dough obtained in step (1) into sheets, cutting into strips, and drying to obtain a low-glycemic-index hanging noodle.

[0035] In the present invention, the mass-volume ratio of the multi-grain flour to water during mixing is 80-120 g: 35-45 mL, preferably 100 g: 40 mL.

[0036] In the present invention, the thickness of the pressing is 0.4-1.2 mm, preferably 0.6-1.0 mm, more preferably 0.8 mm, the number of pressing times is 8-12 times, preferably 9-11 times, more preferably 10 times.

[0037] In the present invention, the width of the strip cutting is 1-2 mm, preferably 1.5 mm.

[0038] In the present invention, the drying includes first drying, second drying and third drying carried out in sequence;

[0039] The temperature of the first drying is 30-35 °C, preferably 33 °C, the humidity is 80-90%, preferably 85%, and the time is 60-90 min, preferably 80 min;

[0040] The temperature of the second drying is 40-45°C, preferably 42°C, the humidity is 70-80%, preferably 75%, and the time is 120-150 min, preferably 140 min;

[0041] The temperature of the third drying is 30-35°C, preferably 33°C, the humidity is 60-70%, preferably 65%, and the time is 60-90 min, preferably 75 min.

[0042] The technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0043] Example 1

[0044] A method for preparing low glycemic index noodles, the steps are as follows:

[0045] (1) Pass 25 parts of wheat flour (amylose content ≥ 30%) made from Lunxuan 49, 10 parts of buckwheat flour, 5 parts of oat flour, 10 parts of corn starch, 10 parts of highland barley flour, 8 parts of oat dietary fiber powder, 10 parts of gluten powder, 8 parts of wheat dietary fiber powder, 5 parts of rye flour, 3 parts of tartary buckwheat flour, 3 parts of quinoa flour, and 3 parts of coix seed powder through a 100-mesh sieve respectively; then mix the sieved buckwheat flour, oat flour, highland barley flour, tartary buckwheat flour, quinoa flour, and coix seed powder and further pulverize them with a pneumatic ultrafine pulverizer, with a pulverizing pressure of 0.75 MPa and a sorting frequency of 32 Hz. Mix the processed raw materials evenly to obtain multi-grain flour.

[0046] (2) Mix the multi-grain flour obtained in step (1) with water according to a mass-volume ratio of 100 g: 40 mL to obtain a multi-grain dough.

[0047] (3) Press the multi-grain dough obtained in step (2) with a machine, press it 10 times according to a thickness of 0.8 mm, cut the dough sheet into noodles with a width of 1.5 mm, first dry it at a temperature of 30°C and a humidity of 80% for 60 min, then dry it at a temperature of 40°C and a humidity of 70% for 120 min, and finally dry it at a temperature of 30°C and a humidity of 60% for 90 min to obtain low glycemic index noodles.

[0048] Example 2

[0049] A method for preparing low glycemic index noodles, the steps are as follows:

[0050] (1) Weigh 30 parts of wheat flour (amylose content ≥ 30%) made from Lunxuan 49, 8 parts of buckwheat flour, 4 parts of oat flour, 10 parts of corn starch, 10 parts of hulless barley flour, 8 parts of oat dietary fiber powder, 10 parts of vital wheat gluten, 8 parts of wheat dietary fiber powder, 3 parts of rye flour, 3 parts of tartary buckwheat flour, 3 parts of quinoa flour, and 3 parts of coix seed powder respectively, and pass them through a 100-mesh sieve. Then mix the sieved buckwheat flour, oat flour, hulless barley flour, tartary buckwheat flour, quinoa flour, and coix seed powder, and further crush them with a pneumatic ultrafine mill at a crushing pressure of 0.8 MPa and a sorting frequency of 40 Hz. Mix all the processed raw materials evenly to obtain multi-grain flour.

[0051] (2) Mix the multi-grain flour obtained in step (1) with water at a mass-to-volume ratio of 100 g:40 mL to obtain a multi-grain dough.

[0052] (3) Press the multi-grain dough obtained in step (2) with a machine, press it 10 times at a thickness of 0.8 mm, cut the dough sheet into noodles with a width of 1.5 mm, first dry it at a temperature of 35 °C and a humidity of 80% for 60 min, then dry it at a temperature of 45 °C and a humidity of 80% for 120 min, and finally dry it at a temperature of 35 °C and a humidity of 65% for 60 min to obtain low glycemic index noodles.

[0053] Example 3

[0054] A method for preparing low glycemic index noodles, the steps are as follows:

[0055] (1) Weigh 30 parts of wheat flour (amylose content ≥ 30%) made from Lunxuan 49, 10 parts of buckwheat flour, 5 parts of oat flour, 5 parts of corn starch, 10 parts of hulless barley flour, 8 parts of oat dietary fiber powder, 10 parts of vital wheat gluten, 8 parts of wheat dietary fiber powder, 5 parts of rye flour, 3 parts of tartary buckwheat flour, 3 parts of quinoa flour, and 3 parts of coix seed powder respectively, and pass them through a 100-mesh sieve. Then mix the sieved buckwheat flour, oat flour, hulless barley flour, tartary buckwheat flour, quinoa flour, and coix seed powder, and further crush them with a pneumatic ultrafine mill at a crushing pressure of 0.75 MPa and a sorting frequency of 40 Hz. Mix all the processed raw materials evenly to obtain multi-grain flour.

[0056] (2) Mix the multi-grain flour obtained in step (1) with water at a mass-to-volume ratio of 100 g:40 mL to obtain a multi-grain dough.

[0057] (3) Press the multi-grain dough obtained in step (2) with a machine, press it 10 times at a thickness of 0.8 mm, cut the dough sheet into noodles with a width of 1.5 mm, first dry it at a temperature of 30 °C and a humidity of 85% for 90 min, then dry it at a temperature of 45 °C and a humidity of 70% for 150 min, and finally dry it at a temperature of 30 °C and a humidity of 60% for 90 min to obtain low glycemic index noodles.

[0058] Example 4

[0059] A method for preparing low glycemic index noodles, the steps are as follows:

[0060] (1) Pass 20 parts of wheat flour (amylose content ≥ 30%) made from Lunxuan 49, 10 parts of buckwheat flour, 5 parts of oat flour, 10 parts of corn starch, 10 parts of highland barley flour, 10 parts of oat dietary fiber powder, 10 parts of vital wheat gluten, 10 parts of wheat dietary fiber powder, 4 parts of rye flour, 3 parts of tartary buckwheat flour, 4 parts of quinoa flour, and 4 parts of coix seed powder through a 100-mesh sieve respectively; then mix the sieved buckwheat flour, oat flour, highland barley flour, tartary buckwheat flour, quinoa flour, and coix seed powder and further crush them with a pneumatic ultrafine mill, with a crushing pressure of 0.75 MPa and a sorting frequency of 40 Hz. Mix the processed raw materials evenly to obtain multi-grain flour.

[0061] (2) Mix the multi-grain flour obtained in step (1) with water according to a mass-volume ratio of 100 g: 40 mL to obtain a multi-grain dough.

[0062] (3) Press the multi-grain dough obtained in step (2) with a machine, press it 10 times with a thickness of 0.8 mm, cut the dough sheet into noodles with a width of 1.5 mm, first dry it at a temperature of 30 °C and a humidity of 85% for 80 min, then dry it at a temperature of 45 °C and a humidity of 70% for 150 min, and finally dry it at a temperature of 30 °C and a humidity of 60% for 90 min to obtain low glycemic index noodles.

[0063] Example 5

[0064] A method for preparing low glycemic index noodles, the steps are as follows:

[0065] (1) Pass 30 parts of wheat flour (amylose content ≥ 30%) made from Lunxuan 49, 10 parts of buckwheat flour, 5 parts of oat flour, 10 parts of corn starch, 10 parts of highland barley flour, 8 parts of oat dietary fiber powder, 5 parts of vital wheat gluten, 8 parts of wheat dietary fiber powder, 4 parts of rye flour, 4 parts of tartary buckwheat flour, 3 parts of quinoa flour, and 3 parts of coix seed powder through a 100-mesh sieve respectively; then mix the sieved buckwheat flour, oat flour, highland barley flour, tartary buckwheat flour, quinoa flour, and coix seed powder and further crush them with a pneumatic ultrafine mill, with a crushing pressure of 0.8 MPa and a sorting frequency of 40 Hz. Mix the processed raw materials evenly to obtain multi-grain flour.

[0066] (2) Mix the multi-grain flour obtained in step (1) with water according to a mass-volume ratio of 100 g: 40 mL to obtain a multi-grain dough.

[0067] (3) Press the multi-grain dough obtained in step (2) with a machine, press it 10 times at a thickness of 0.8 mm, cut the dough sheet into noodles with a width of 1.5 mm, first dry it at a temperature of 35 °C and a humidity of 80% for 60 min, then dry it at a temperature of 45 °C and a humidity of 80% for 150 min, and finally dry it at a temperature of 35 °C and a humidity of 65% for 60 min to obtain low glycemic index noodles.

[0068] Control example

[0069] A method for preparing noodles, the steps are as follows:

[0070] (1) Pass 30 parts of ordinary wheat flour (the amylose content is about 22%), 8 parts of buckwheat flour, 4 parts of oat flour, 10 parts of corn starch, 10 parts of highland barley flour, 8 parts of oat dietary fiber powder, 10 parts of vital wheat gluten, 8 parts of wheat dietary fiber powder, 3 parts of rye flour, 3 parts of tartary buckwheat flour, 3 parts of quinoa flour, and 3 parts of coix seed powder through a 100-mesh sieve respectively; then mix the sieved buckwheat flour, oat flour, highland barley flour, tartary buckwheat flour, quinoa flour, and coix seed powder and further crush them with a pneumatic ultrafine mill, with a crushing pressure of 0.8 MPa and a sorting frequency of 40 Hz. Mix the processed raw materials evenly to obtain multi-grain flour.

[0071] (2) Mix the multi-grain flour obtained in step (1) with water at a mass-volume ratio of 100 g:40 mL to obtain a multi-grain dough.

[0072] (3) Press the multi-grain dough obtained in step (2) with a machine, press it 10 times at a thickness of 0.8 mm, cut the dough sheet into noodles with a width of 1.5 mm, first dry it at a temperature of 35 °C and a humidity of 80% for 80 min, then dry it at a temperature of 45 °C and a humidity of 80% for 140 min, and finally dry it at a temperature of 35 °C and a humidity of 65% for 75 min to obtain noodles.

[0073] Experimental example 1

[0074] Taking commercially available ordinary wheat noodles (the raw material composition is wheat flour and water, Jinlongyu chewy noodles) as a control, conduct a sensory evaluation on the noodles prepared in Examples 1-5 and the control example. The sensory evaluation team consists of 15 teachers and students majoring in food science. The evaluation criteria are shown in Table 1. After each evaluator scores, take the average value to obtain the scoring result evaluation, and the results are shown in Table 2.

[0075] Table 1 Sensory evaluation criteria

[0076]

[0077] Table 2 Sensory evaluation results

[0078]

[0079]

[0080] As can be seen from Table 2, compared with the control, the sensory evaluation results of the dried noodles prepared in Examples 1 to 5 and the comparative example are lower, indicating that the content of wheat flour has an obvious effect on the sensory evaluation results of dried noodles. The sensory score results of the dried noodles prepared in Example 2 and Example 3 are significantly higher than those in Example 1, Example 4 and Example 5, indicating that adjusting the raw material ratio of multi-grain flour can, through the synergistic effect among the raw materials, keep the noodles in good color, shape, flavor and taste.

[0081] Experimental Example 2

[0082] Taking commercially available ordinary wheat dried noodles as the control, the breaking rate and cooking loss rate of the dried noodles prepared in Examples 1 to 5 and the comparative example were measured.

[0083] 1. Noodle breaking rate

[0084] Accurately weigh 20 dried noodles, fish them out after cooking at the optimal cooking time (i.e., the time when the white core disappears during the noodle cooking process), put them into 200 mL of cold water and let them stand for 30 s, and calculate the breaking rate according to the formula.

[0085] B = N1 / N2×100

[0086] In the formula: B is the breaking rate, %; N1 is the number of broken noodles, pieces; N2 is the total number of cooked noodles, pieces.

[0087] 2. Cooking loss rate

[0088] Accurately weigh 10.0 g of dried noodles, put them into 200 mL of water, fish them out after cooking to the optimal cooking time, put the noodles into 200 mL of cold water and let them stand for 30 s, pour the noodle soup and the cold water for standing the noodles into a 1000 mL volumetric flask for constant volume, shake well, take 50 mL of the noodle soup from the volumetric flask and place it in a covered aluminum box dried to constant weight, dry it at 105 °C for 4 h to constant weight, and calculate the cooking loss rate according to the formula. Each sample was measured in parallel 3 times.

[0089]

[0090] In the formula: m0——the mass of the dried noodles before cooking, g;

[0091] m1——the mass of the dried noodles after cooking, g;

[0092] m——the dry matter mass after drying 50 mL of the constant volume noodle soup, g;

[0093] w——the moisture content of the dried noodles, %.

[0094] The measurement results are shown in Table 3. It can be seen that, compared with Examples 1 to 3, the breakage rate and cooking loss rate of the dried noodles prepared in Examples 4 and 5 are significantly higher, indicating that when the content of wheat flour and vital gluten is low, the breakage rate and cooking loss rate increase, and adjusting the raw material ratio of the multi-grain flour can reduce the breakage rate and cooking loss rate of the dried noodles.

[0095] Table 3 Results of breakage rate and cooking loss rate

[0096] Sample Breaking rate Cooking loss rate Control 0％ 6.5％ Comparative example 5％ 6.8％ Example 1 0％ 7.1％ Example 2 0％ 6.5％ Example 3 0％ 6.8％ Example 4 5％ 8.3％ Example 5 5％ 8％

[0097] Experimental Example 3

[0098] Taking commercially available ordinary wheat dried noodles as a control, the starch hydrolysis index and predicted glycemic index of the dried noodles prepared in Examples 1 to 5 and the comparative examples were measured.

[0099] 1. Reagent preparation

[0100] Buffer1: Take 1.75 mL of concentrated hydrochloric acid and make up the volume to 1 L with deionized water.

[0101] Buffer2: Take 11.8 mL of glacial acetic acid and dissolve it in 800 mL of deionized water. Add 2 mol / L NaOH solution to adjust the pH to 6. Then add 4 mL of 1 mol / L CaC l2 solution and 100 μL of 4.9 mol / L MgCl2 solution, and make up the volume to 1 L with deionized water.

[0102] Enzyme A: Take 6.25 mg of pepsin (P6887) and dissolve it in 50 mL of Buffer1.

[0103] Enzyme B: Take 75 mg of pancreatic mixed enzymes (P1750) and 33 mg of α-glucosidase solution and dissolve them in 25 mL of Buffer2.

[0104] 2. Determination of starch hydrolysis index and predicted glycemic index

[0105] Take 150 - 200 mg (calculated according to the carbohydrate content of the sample) of the dried noodle sample and put it into a 25 mL centrifuge tube, and place three glass beads. Add 2 mL of Enzyme A, then place it in a constant temperature shaker at 37 °C and 150 r / min for shaking treatment for 30 min. Add 4 mL of Buffer2 and shake for 5 min, then add 1 mL of Enzyme B and start timing. Take out 100 μL of the digestive juice at 0, 30, 60, 90, 120, and 180 min respectively, inactivate the enzyme in a boiling water bath for 5 min, add 150 μL of DNS solution, and boil in a water bath for another 5 min for color development, and measure the glucose content therein.

[0106] Sampling amount (μg) = 5000 ÷ carbohydrate content

[0107] Degree of starch hydrolysis = Glucose content at sampling point / Total starch content

[0108] Taking the hydrolysis time of the sample as the abscissa and the degree of starch hydrolysis as the ordinate, use Origin 2019 to analyze the integral area (AUC1) under the hydrolysis curve. Taking the integral area under the hydrolysis curve of the pregelatinized starch as the control (AUC0), calculate the starch hydrolysis index HI and the predicted glycemic index (pGI).

[0109] HI = (AUC1 / AUC0) × 100%

[0110] pGI = 0.862HI + 8.192

[0111] Table 4 Determination results of starch hydrolysis index and predicted glycemic index

[0112] Sample HI value pGI value Control 82.49 79.3 Comparative example 52.33 53.3 Example 1 48.15 49.7 Example 2 47.34 49.0 Example 3 51.98 53.0 Example 4 46.53 48.3 Example 5 48.50 50.0

[0113] As can be seen from Table 4, the starch hydrolysis index and the predicted glycemic index of the noodles prepared by the present invention are significantly lower than those of the control, indicating that the noodles prepared by the method of the present invention are an excellent low-GI food, especially suitable for people with high blood sugar.

[0114] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A multi-grain flour with a low glycemic index, characterized in that The invention comprises the following raw materials in parts by weight: 20-30 parts of wheat flour, 5-10 parts of buckwheat flour, 3-5 parts of oat flour, 5-10 parts of corn starch, 5-10 parts of highland barley flour, 5-10 parts of oat dietary fiber powder, 5-10 parts of gluten powder, 5-10 parts of wheat dietary fiber powder, 3-5 parts of rye flour, 3-5 parts of tartary buckwheat flour, 3-5 parts of quinoa flour and 3-5 parts of coix seed flour.

2. The multi-grain flour according to claim 1, characterized in that The wheat flour is wheat flour with an amylose content of ≥30%.

3. A method for preparing the multi-grain flour according to claim 1 or 2, characterized in that: The formulated amounts of the raw materials are mixed to obtain the multi-grain flour.

4. The method according to claim 3, characterized in that Before the mixing, all the raw materials are sieved through a 80-120 mesh sieve; the buckwheat flour, oat flour, highland barley flour, bitter buckwheat flour, quinoa flour and coix kernel flour are sieved and then ultrafinely ground, the ultrafinely ground pressure is 0.75-0.85 MPa, and the sorting frequency is 32-40 Hz.

5. Use of the multi-grain flour according to claim 1 or 2 or the multi-grain flour prepared according to the method of claim 3 or 4 in preparing food with a low glycemic index.

6. The use according to claim 5, characterized in that The food includes noodles and biscuits.

7. A method for preparing noodles with a low glycemic index, characterized in that: The steps include: (1) mixing the multi-grain flour according to claim 1 or 2 or the multi-grain flour prepared according to the method of claim 3 or 4 with water to obtain a multi-grain dough; (2) sheeting the multi-grain dough obtained in step (1), cutting into strips, and drying to obtain noodles with a low glycemic index.

8. The method according to claim 7, characterized in that The thickness of the tablet is 0.4-1.2 mm, and the number of tablet pressing is 8-12 times.

9. The method according to claim 7, characterized in that The drying comprises first drying, second drying and third drying performed sequentially; The first drying is performed at a temperature of 30-35°C, a humidity of 80-90%, and a time of 60-90 minutes; The second drying process is performed at a temperature of 40 to 45°C, a humidity of 70 to 80%, and a time of 120 to 150 minutes; The third drying process is performed at a temperature of 30-35° C., a humidity of 60-70%, and a time of 60-90 minutes.

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