CN115428953A

CN115428953A - Low-GI pastry premixed powder and preparation method of product thereof

Info

Publication number: CN115428953A
Application number: CN202211271703.9A
Authority: CN
Inventors: 李俊堃; 肖嘉敏
Original assignee: Shenzhen Dynamic Balanced Health Technology Co ltd
Current assignee: Shenzhen Dynamic Balanced Health Technology Co ltd
Priority date: 2022-10-18
Filing date: 2022-10-18
Publication date: 2022-12-06

Abstract

The invention provides low-GI pastry premixed flour and a preparation method of a product thereof, and belongs to the technical field of food processing. The pastry premixed powder comprises the following components in parts by weight: 20-60 parts of coarse cereals, 5-63 parts of wheat gluten, 0-30 parts of natural sugar substitutes, 0.1-0.7 part of mulberry leaf extracts and 5-45 parts of soluble dietary fibers; wherein the soluble dietary fiber includes, but is not limited to: inulin, resistant dextrin, polydextrose, fructo-oligosaccharide and isomaltooligosaccharide. The pastry premixed flour is applied to pastry preparation, the prepared pastry has lower GI, and under the condition of not adding sugar, flour and less oil, the pastry is moist and chewy, has good taste, compact gluten network, uniform air holes and good elasticity and resilience, and is suitable for people with diabetes and obesity to eat.

Description

Low-GI pastry premixed flour and preparation method of product thereof

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to low-GI pastry premixed flour and a preparation method of a product thereof.

Background

At present, staple food of residents mainly comprises rice and wheat, and with the development of society, the progress of production and processing technology and the like, the refined white rice flour gradually becomes a basic component on dining tables of people. With the change of dietary structure, the number of diabetic patients in China is continuously increased due to long-term dietary imbalance, and with the continuous extension of the life cycle of chronic patients, and the influence of aging population, urbanization and industrialization process and prevalence of behavior risk factors on the attack of chronic diseases, the basic number of the diabetic patients is continuously expanded.

The nutrition balance of the staple food is the key point for the diabetic to regulate and control the blood sugar. Researches show that the ingestion of low Glycemic Index (GI) food can effectively avoid postprandial blood sugar fluctuation, enhance satiety, effectively improve the blood sugar level of diabetics and reduce the risk of residents suffering from type 1 or type 2 diabetes. However, in the conventional actual case research, the diabetes patients can not effectively control the blood sugar by reducing or stopping the intake of the staple food, and the key point of controlling the blood sugar is that the staple food selects high-quality complex carbohydrates (low-GI foods) and the balance of diet and nutrition is.

The pastry is used as staple food, has strong satiety and is widely popular with people in China. At present, staple food for diabetics is mainly rice and noodles, the rice is mainly varieties rich in amylose or resistant starch and the like, part of the staple food is supplemented with coarse cereals, the low-GI rice is mainly eaten as rice, most of the rice cannot be cooked into porridge, and the selection of part of diabetics as breakfast is limited. The low-GI noodles are mainly added with coarse cereals which are not sticky enough, and various edible colloids are required to be used as adhesives, so that the noodles have better cooking performance and mouthfeel; however, most of noodle toppings have heavy tastes of high sugar, high fat, high salt and are not beneficial to regulating and controlling blood sugar. Low GI pastries such as steamed bread, steamed stuffed buns, bread, etc. are rare. This is mainly because: (1) The raw materials for preparing the pastries need to be crushed, and the crushed raw materials may have increased fineness, increased damage degree of starch and increased GI value; (2) During proofing for making the pastries, however, there is a need to provide sufficient starch to allow yeast growth and sufficient gluten to support the formation of the pastries. The coarse cereal flour has poor processing performance, is difficult to form gluten or form dough with poor elasticity and ductility, and is difficult to prepare flour products with high gluten requirement, such as coarse cereal pastry and the like. In the prior art, wheat flour and a gluten-strengthening enzyme preparation are mostly added to improve the gluten strength, and the prepared pastry has an unsatisfactory sugar control effect. At present, most of bread mainly for reducing sugar in the market is prepared by whole wheat flour or single coarse cereal flour, the bread has the conditions of poor taste and difficult swallowing, the GI value of the bread is actually measured and is not low in a human body and basically higher than 55, and the bread does not reach the low GI standard (GI < =55 is low GI food) (Yang Yuehenxin, wangguan, panxing Chang Main edition, chinese food ingredient table, 2 nd edition [ M ]. Beijing: beijing medical university Press, 2009.).

Chinese invention patent CN110089536A discloses a low GI hulless oat premixed flour without flour and a preparation method of a product thereof, the premixed flour comprises component modified hulless oat flour, exogenous protein, TG enzyme, compound hydrophilic colloid, a complex enzyme preparation and seasoning auxiliary materials, and the prepared hulless oat bread has uniform pores, fine and smooth tissue, softness, no tooth sticking, elasticity and low glycemic index. However, the method needs high-pressure, radio-frequency and enzyme pretreatment on the hulless oat, the cost is high, the operation is complicated, and the scheme cannot be popularized and applied to other coarse cereal powder.

At present, the low GI bread on the market is mostly prepared by adding gluten flour into wheat gluten, adding coarse cereal flour or whole wheat flour into the gluten flour and other bread modifying agents. The Chinese invention patent CN114258932A discloses slow-boiled sugar European bread premixed flour and a preparation method of the slow-boiled sugar European bread premixed flour. Different coarse cereal raw materials are crushed to different mesh numbers and matched, and the digestion speed of starch is adjusted, so that the aim of reducing the GI value of the premixed flour is fulfilled. However, the bread has coarser particles, which affects swallowing and eating experience, and the use of strong flour causes great blood sugar fluctuation.

Therefore, the premixed flour for preparing pastries needs to be reasonably matched with all components under the condition of meeting the requirement of low GI (glycemic index), so that the pastries have good proofness and network structure, and the palatability of the mouthfeel is ensured.

Disclosure of Invention

The invention provides low-GI pastry premixed flour and a preparation method of a product thereof, aiming at the problems in the prior art. The invention overcomes the problem of single type of low GI premixed flour minor cereals in previous researches, and provides low GI coarse cereals with various types and high dietary fiber content, and the low GI premixed flour with low glycemic index is obtained by adding an active ingredient mulberry leaf extract to inhibit amylase and glucosidase. The coarse cereals and the foreign protein are reasonably proportioned to ensure the forming; the foreign protein can regulate the starch digestion speed and reduce the GI value of the product, and the prepared bread is moist, chewy and good in taste.

In order to realize the purpose, the technical scheme adopted by the invention is as follows:

firstly, the invention provides low GI pastry premixed flour which comprises the following components: coarse cereals, wheat gluten, natural sugar substitutes, mulberry leaf extract and soluble dietary fibers.

Preferably, the low-GI pastry premixed flour comprises the following components in parts by weight: 20-60 parts of coarse cereals, 5-63 parts of wheat gluten, 0-30 parts of natural sugar substitutes, 0.1-0.7 part of mulberry leaf extracts and 5-45 parts of soluble dietary fibers.

Further preferably, the low-GI pastry premixed flour comprises the following components in parts by weight: 35-50 parts of coarse cereals, 11-45 parts of wheat gluten, 5-20 parts of natural sugar substitutes, 0.2-0.5 part of mulberry leaf extracts and 10-40 parts of soluble dietary fibers.

Further preferably, the low-GI pastry premixed flour comprises the following components in parts by weight: 43 parts of coarse cereals, 36 parts of wheat gluten, 8 parts of natural sugar substitutes, 0.4 part of mulberry leaf extract and 12.6 parts of soluble dietary fibers.

Preferably, the mass ratio of the coarse cereals to the wheat gluten is 1.3-1.05.

Further preferably, the mass ratio of the coarse cereals to the wheat gluten is 1:0.5-1.01.

Preferably, the mass ratio of the mulberry leaf extract to available carbohydrate is 1.

Further preferably, the mass ratio of the mulberry leaf extract to available carbohydrate is 1:50-100.

Preferably, the natural sugar substitute is selected from at least one of erythritol, maltitol, isomalt, sorbitol, mogroside, xylitol, and thaumatin.

Preferably, the available carbohydrate is indigestible polysaccharide in the formula of the reduced pastry premixed flour, inulin, polydextrose, guar gum, microcrystalline cellulose, carrageenan, xanthan gum and pectin.

Preferably, the soluble dietary fiber includes, but is not limited to: one or more of inulin, resistant dextrin, polydextrose, fructo-oligosaccharide and isomaltose hypgather.

Further preferably, the soluble dietary fiber is selected from at least one of inulin and resistant dextrin.

Preferably, the coarse cereals include but are not limited to one or more of linseed, quinoa, barley, small red bean, small green bean, tartary buckwheat, soybean, chickpea, highland barley and oat bran.

Preferably, the coarse cereal pretreatment method comprises the following steps: the coarse cereals are crushed and ground and then are sieved by a 40-90 mesh sieve.

Preferably, the gluten protein content is greater than or equal to 76%.

Preferably, the inulin is: the chicory root is taken as a raw material, protein and mineral substances are removed, and the chicory root is subjected to spray drying and other steps to obtain the chicory root extract.

Still further, the present invention provides a method of preparing low GI toast using the aforementioned pastry premixed flour, which method may be prepared with reference to a general bread making process, comprising the steps of:

(1) Adding 800-1000g of pastry premixed flour, 400-600ml of water, 40-60g of eggs, 0-5g of salt, 0-100g of butter, 40-60g of fresh yeast and 5-15g of glycerol according to a proportion, and kneading into dough;

(2) Shaping, fermenting and baking dough: shaping the dough, putting into a mold, fermenting for 90-120min at 37 deg.C and 85% humidity, heating to 190-220 deg.C, heating to 210-230 deg.C, and baking for 30-50min to obtain low GI pastry.

Preferably, the low-GI pastry is a low-GI product with a GI value of less than 55 through detection, and the product is moist, delicious, chewy, fine and uniform in tissue, fragrant in grain and strong in satiety.

Finally, the invention provides the use of the pastry premixed flour described above in the preparation of low-GI bread, chinese pastries, western pastries, cakes, noodles, biscuits.

Preferably, the low GI bread is toast bread, multi-bread, french bread, english bread, danish bread, toast bread.

Preferably, the Chinese style pastries include, but are not limited to, steamed bread, steamed stuffed buns, rolled pancakes, and dumplings; the western-style pastries include, but are not limited to, pizza, and behaved.

Compared with the prior art, the invention has the following beneficial effects:

(1) The coarse cereals containing high-quality complex carbohydrate are selected and matched with a certain proportion of exogenous protein vital gluten to form the wrapping effect of the exogenous protein on starch, so that the digestion and absorption speed of the starch is slowed down, the activity of alpha-amylase and glucosidase is inhibited, and the hydrolysis of the starch is limited. Meanwhile, the mulberry leaf extract is added according to the content of carbohydrate, so that the effect of low GI is finally achieved, and the effects of reducing blood sugar fluctuation, slowly increasing sugar and avoiding the excessive energy from being converted into fat are achieved.

(2) Through the compounding of coarse cereals, exogenous protein vital gluten and mulberry leaf extract in a specific proportion, the content of soluble dietary fiber is increased, the viscosity of food is increased, the content with increased viscosity forms a layer of gel on the surface of starch granules, the contact between digestive enzyme and starch is blocked, the digestion speed is slowed down, the blood sugar reducing effect is enhanced, the intestinal health effect is improved, and the problem of excessive dietary fiber content and poor taste is solved.

(3) Refined sugar and little oil are not added in the prepared toast formula, so that the requirement of making low-sugar toast in daily families can be met, the toast formula can also adapt to the industrial production condition of toast, the defects that the toast without wheat flour is difficult to ferment, small in volume, incapable of being formed, poor in taste and the like are overcome, the prepared toast has an obvious blood sugar control function, the taste and the taste are more easily accepted by consumers, and the toast formula can be applied to industrial generation and has good social and economic benefits.

Drawings

FIG. 1 is a blood glucose response curve of example 1 of the present invention.

Detailed Description

The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way. The following is merely an exemplary illustration of the scope of the claims of the present application and various changes and modifications of the invention of the present application may be made by those skilled in the art based on the disclosure, which should also fall within the scope of the claims of the present application.

The present invention will be further described below by way of specific examples. The various chemicals used in the examples of the present invention were obtained by conventional commercial routes unless otherwise specified.

In the following examples, the mulberry leaf extract is purchased from Santong as

Mulberry leaf extract product.

Example 1

Pretreatment of coarse cereals: respectively crushing the black highland barley, the quinoa and the flaxseeds and sieving the crushed materials with a 90-mesh sieve to obtain coarse cereal raw materials; crushing oat, sieving with a 40-mesh sieve, and taking oversize products; and (5) mixing to obtain the coarse cereal raw material.

43 parts of coarse cereals, wherein 4 parts of quinoa, 27 parts of highland barley, 9 parts of oat bran and 3 parts of flaxseed;

36 parts of vital gluten;

6 parts of inulin;

8 parts of erythritol;

0.4 part of mulberry leaf extract;

6.6 parts of resistant dextrin;

the raw materials are mixed and stirred uniformly to obtain the pastry premixed flour.

The pastry premixed flour is used for preparing toast bread, and the steps are as follows:

(1) Adding 1000g of pastry premixed flour, 600ml of water, 50g of eggs, 5g of salt, 65g of butter, 50g of fresh yeast and 10g of glycerol according to a proportion, and kneading into smooth dough at room temperature;

(2) Shaping, fermenting and baking dough: shaping the dough, putting into a mold, fermenting at 37 deg.C and 85% humidity for 110min, heating to 190 deg.C and heating to 220 deg.C, and baking for 40min to obtain the low GI toast.

The resulting toasted bread had a GI value of 46.

Example 2

Different from the embodiment 1, the pastry premixed flour has different components in parts by weight:

52.4 parts of coarse cereals, wherein 8 parts of quinoa, 27.4 parts of highland barley, 9 parts of oat bran and 8 parts of flaxseed;

26.3 parts of wheat gluten;

6 parts of inulin;

8 parts of erythritol;

0.7 part of mulberry leaf extract;

6.6 parts of resistant dextrin;

The remaining steps and parameters were the same as in example 1.

The resulting toasted bread GI value was 54.

Example 3

40.5 parts of coarse cereals, wherein 3 parts of quinoa, 20 parts of highland barley, 14 parts of oat bran and 3.5 parts of flaxseed.

41 parts of vital gluten;

6 parts of inulin;

6 parts of erythritol;

0.2 part of mulberry leaf extract;

6.3 parts of resistant dextrin;

The remaining steps and parameters were the same as in example 1.

The resulting toasted bread had a GI value of 53.

Example 4

Different from the embodiment 1, the pastry premixed flour is different from coarse cereals in the pastry premixed flour, and the coarse cereal used in the embodiment 4 is only quinoa in 43 parts.

The remaining steps and parameters were the same as in example 1.

The resulting toasted bread had a GI value of 49.

Example 5

Different from the embodiment 1, the grain size of the coarse cereals is different, in the embodiment, the highland barley, the quinoa and the flaxseeds are sieved by a 40-mesh sieve, and the oat bran is sieved by a 90-mesh sieve.

The remaining steps and parameters were the same as in example 1.

The resulting toasted bread had a GI value of 52.

Example 6

Unlike example 1, in the preparation method of toast, in step (1), 1000g of pastry premixed flour, 650ml of water, 100g of eggs, 5g of salt, 100g of butter, 60g of fresh yeast and 10g of glycerin were kneaded into smooth dough at room temperature.

The remaining steps and parameters were the same as in example 1.

The resulting toasted bread had a GI value of 50.

Comparative example 1

Common toast is sold commercially.

The ingredients are wheat high-gluten flour, sugar, salt, fresh yeast, pure milk, butter and condensed milk;

the preparation method comprises the following steps:

(1) The method comprises the following steps of (1) agglomerating 110g of wheat high gluten flour, 10g of sugar, 100g of fresh milk and 9g of condensed milk at a low speed;

(2) Adding 5g of fresh yeast into the dough, kneading for 4min, adding 2g of salt, continuously kneading until the dough is smooth, elastic and slightly malleable and can be torn off a thick film, adding 20g of softened butter, kneading until the dough can be easily pulled open to form a film which is elastic and has smooth broken hole edges;

(3) Fermentation: primary fermentation: the temperature is 28 ℃, the humidity is 75%, and the fermentation time is 30min; and (3) secondary fermentation: fermenting at 33 deg.C and 85% humidity until 9 min;

(4) Baking: baking at 150 deg.C and 230 deg.C for 35min.

The resulting toast had a GI value of 76.

Comparative example 2

Unlike example 1, the components of the pastry premix flour do not include vital wheat gluten. The remaining steps and parameters were the same as in example 1.

The resulting toasted bread had a GI value of 59.

Comparative example 3

Unlike example 1, the components of the pastry premixed flour do not include mulberry leaf extract. The remaining steps and parameters were the same as in example 1.

The resulting toasted bread had a GI value of 60.

Comparative example 4

Unlike example 1, the components of the pastry premixed flour do not include gluten and 30 parts of wheat flour is added to the components. The remaining steps and parameters were the same as in example 1.

The resulting toasted bread had a GI value of 70.

Comparative example 5

Unlike example 1, the components of the pastry premixed flour do not include vital wheat gluten and mulberry leaf extract. The remaining steps and parameters were the same as in example 1.

The resulting toasted bread GI value was 67.

Comparative example 6

Different from the embodiment 1, the coarse cereals are crushed and sieved by a 200-mesh sieve. The remaining steps and parameters were the same as in example 1.

The resulting toasted bread had a GI value of 57.

Product detection 1: blood glucose test method reference standard: in the test, a subject is selected, tested food is processed, and human blood glucose measurement and food GI calculation are carried out according to a method of WS/T625-2019 food blood glucose generation index determination.

The blood sugar test method comprises the following steps:

(1) Each product assay cycle included 3 independent feeding assays, with product 1 and glucose reference 2;

(2) The interval of each independent food test is more than or equal to 72h, and the test product is arranged between 2 glucose reference sample food tests;

(3) The blood sampling part can be fingertip capillary blood (whole blood);

(4) Collecting blood samples respectively at fasting state (twice), postprandial 15min, 30min, 45min, 60min, 90min and 120min, and recording blood glucose concentration;

the GI calculation method comprises the following steps:

in the formula: GIn-individual GI value from subject;

at-the IAUC value (the area increase value under the blood sugar response curve) of the food to be detected;

-mean value of at least 2 reference foods IAUC measured for the same individual;

GI-GI value of food to be measured;

Σ GIn — sum of GI values derived from each subject individual;

n-number of subjects who eventually received the GI value calculation for the test food.

Test food:

(1) Reference food: anhydrous glucose, the manufacturer is Kangmeibao Ning (Sichuan) pharmaceutical Co., ltd; 25g of food-grade anhydrous glucose is taken and purified water is added to dissolve the food-grade anhydrous glucose to 250ml.

(2) The tested food: toasted bread prepared in the examples and comparative examples of the present application.

Available carbohydrate content = total carbohydrates-dietary fibers-fructooligosaccharides-galactooligosaccharides-polydextrose-resistant maltodextrin-resistant starch and like unusable carbohydrates in the test food that could not be determined by GB 5009.88-2014;

the amount of the test food (g) = target amount of available carbohydrate (g)/amount of available carbohydrate in the test food (g/100 g);

each test food was taken with 250ml of water.

The test food grade test food dosage is shown in table 1:

TABLE 1

Subject: 72 subjects, ranging in age from 24-54 years, were randomized into 12 groups:

(1) Healthy adults, non-pregnant women and lactating mothers;

(2) The Body Mass Index (BMI) is within the normal range (18.5 kg/m) ² -24kg/m ² )；

(3) No history of diabetes (or impaired glucose tolerance), no other metabolic diseases, digestive system diseases, endocrine system diseases, mental diseases and the like;

(4) No history of allergy and intolerance to the food to be tested;

(5) Nutrient supplements affecting glucose tolerance, oral contraceptives, acetylsalicylic acid, steroids, protease inhibitors and antipsychotics are not taken within nearly 3 months;

(6) Can tolerate fasting state for at least 10 h.

And (3) analysis: the glucose reference and test food IAUC were calculated according to the standard requirements and the GI value of the bakery product prepared from the pasta premix according to the invention was estimated to be < 55 using the GI value of the glucose reference, which is a low GI food. The commercial bread of comparative example 1 had the highest GI value; the components of the premixed flour are changed, and the GI value is obviously increased, so that the premixed flour disclosed by the application has the advantages that the components of coarse cereals, wheat gluten and mulberry leaf extracts are mutually compatible, the synergistic effect is realized, and the effect of obviously reducing GI is realized; comparative example 6 shows that the size of the grain size of coarse cereals has an influence on the GI value, and that an appropriate grain size is effective in reducing GI.

And (3) product detection 2: the quality sensory evaluation detection method comprises the following steps: the different breads were evaluated according to the standard of GB/T20981-2021 bread, the results of which are shown in Table 2:

subject: also subjects for product test 1.

TABLE 2

As can be seen from table 2: although the overall acceptability of the bread prepared by the pastry premixed flour is not as high as that of the bread sold on the market, the flavor, the texture and the taste of the bread are improved compared with those of a comparative example, and the bread has a very low GI value which is lower than 55 and reaches the index of the low GI value; the breads prepared from the batters of comparative examples 2-6 had lower overall acceptability than the breads of the present application.

And (3) product detection: the detection method of the dough fermentation rheological property comprises the following steps: and measuring the fermentation rheological property of the different bread dough by using an F3 rheometer.

The specific detection steps are as follows: the prepared dough was quickly placed in a fermentation basket and measured according to protocol. The measurement conditions were as follows: the weight of the dough is 315g, the measuring temperature is 35 ℃, the measuring time is 3h, and the weight on the dough is 2000g.

The measured data are shown in Table 3:

TABLE 3

Index (es)	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6
							Hm(mm)	43.2	37.3	41.3	42.8	42.4	42.9
Tx(min)	60.1	54.5	57.4	59.2	59.8	57.6
							R(％)	83.3	72.7	78.9	82.3	82.8	79.6
Index (I)	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5	Comparative example 6
							Hm(mm)	42.5	19.8	42.8	29.7	19.7	39.7
Tx(min)	59.8	30.6	58.4	48.6	30.2	57.4
							R(％)	82.8	40.2	80.2	48.9	40.5	77.7

And (4) product detection: texture analysis of bread

The detection method comprises the following steps: and detecting the texture of the bread by adopting a CT3 10K texture analyzer.

The specific detection steps are as follows: after the bread is cooled for 2h, the bread is cut into slices of 25mm, 3 slices of bread are selected, a core sample in the bread slice is taken, the sample is placed on a platform for TPA measurement, and 3 physical indexes of hardness, chewiness and elasticity are selected. The bread TPA test has the setting parameters as follows: a cylindrical probe TA4 is selected, a trigger point is 5g, a deformation amount is 10mm, a test speed is 3mm/s, and a compression interval time is 5s.

The measured data are shown in Table 4:

TABLE 4

Index (I)	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6
							Hardness per gram	245.5	279.8	246.0	245.1	244.7	243.7
Chewiness of the product	456	478	460	465	455	430
							Elasticity	0.97	0.87	0.96	0.96	0.95	0.85
Index (es)	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5	Comparative example 6
							Hardness per gram	105.3	333.2	246.8	318.7	334.6	240.7
Chewiness of the product	348	512	461	470	520	475
							Elasticity	0.85	0.83	0.94	0.82	0.85	0.84

As can be seen from Table 4, the low GI pastry ready-mix powders of the present invention produced pastry that is moderately soft and rich in chewiness and elasticity.

Finally, it should be noted that the above-mentioned contents are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, and that the simple modifications or equivalent substitutions of the technical solutions of the present invention by those of ordinary skill in the art can be made without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. The low-GI pastry premixed flour is characterized by comprising the following components: coarse cereals, wheat gluten, natural sugar substitutes, mulberry leaf extract and soluble dietary fibers.

2. The pastry premixed flour of claim 1, characterized by comprising the following components in parts by weight: 20-60 parts of coarse cereals, 5-63 parts of wheat gluten, 0-30 parts of natural sugar substitutes, 0.1-0.7 part of mulberry leaf extracts and 5-45 parts of soluble dietary fibers.

3. The pastry premixed flour of claim 2, characterized by comprising the following components in parts by weight: 35-50 parts of coarse cereals, 11-45 parts of wheat gluten, 5-20 parts of natural sugar substitutes, 0.2-0.5 part of mulberry leaf extracts and 10-40 parts of soluble dietary fibers.

4. The pastry premixed flour of claim 3, characterized by comprising the following components in parts by weight: 43 parts of coarse cereals, 36 parts of wheat gluten, 8 parts of natural sugar substitutes, 0.4 part of mulberry leaf extract and 12.6 parts of soluble dietary fibers.

5. The pastry premixed flour of any one of claims 1 to 4, wherein the mass ratio of the minor cereals to the vital wheat gluten is 1; the mass ratio of the mulberry leaf extract to the available carbohydrate is 1; the natural sugar substitute is at least one selected from erythritol, maltitol, isomalt, sorbitol, mogroside, xylitol and thaumatin.

6. The pastry premixed flour of any one of claims 1 to 4, wherein the soluble dietary fiber includes, but is not limited to: one or more of inulin, resistant dextrin, polydextrose, fructo-oligosaccharide and isomalto-oligosaccharide.

7. The pastry premixed powder of any one of claims 1 to 4, wherein the coarse cereals include but are not limited to one or more of flaxseed, quinoa, barley, red bean, green bean, tartary buckwheat, soybean, chickpea, highland barley, oat bran; the coarse cereals are crushed and then screened by a 40-90 mesh sieve.

8. A low GI pastry prepared from the pastry premix powder of any one of claims 1 to 7.

9. The method of preparing a low GI pastry as claimed in claim 8, wherein the low GI pastry is prepared with reference to a general bread making process, comprising the steps of:

(1) Adding 800-1000g of pastry premixed flour, 400-600ml of water, 40-60g of eggs, 0-5g of salt, 0-100g of butter, 40-60g of fresh yeast, 5-15g of glycerol, 0.5g of calcium propionate and 0.35g of sodium dehydroacetate according to the proportion, and kneading into dough;

10. Use of the pastry premix flour of any one of claims 1 to 7 in the preparation of low-GI bread, chinese pastries, western-style pastries, cakes, noodles, biscuits.