Low GI whole wheat bread for improving shelf life of freshly made bread and preparation method thereof

Abstract

The invention relates to low-GI whole-wheat bread for improving the shelf life of freshly made bread, and belongs to the technical field of bread. The whole-wheat bread raw materials include whole-wheat flour, wheat flour, gluten, yeast, whole egg liquid, butter, milk powder, and a compound improver, wherein the compound improver is salt, glucose, trehalose, a compound sweetener composition, and water. Compared with traditional whole-wheat bread, the whole-wheat bread prepared by the method of the invention has the following advantages: 1. It can effectively improve the problems of rough taste and insufficient gluten of whole-wheat bread, and has a better taste; 2. It can significantly improve the shelf life of freshly made bread; 3. It can significantly reduce the GI of bread, which is lower than that of common low-GI bread products on the market.

Description

Technical Field

[0001] The present invention relates to the technical field of bread, and more particularly to a low-GI whole-wheat bread capable of improving the shelf life of freshly made bread and a preparation method thereof. Background Art

[0002] According to industry reports, China's bakery market sales reached 251 billion yuan in 2020 and have been showing a positive upward trend. Bread, in particular, has significant production potential. Most breads are high in butter and sugar, which, while satisfying taste preferences, can have health risks from frequent consumption. In the current green and healthy environment, product concepts that are most attractive to consumers are low in sugar and fat, fresh, made with natural ingredients, and functional health claims. The GI (Glycemic Index) reflects the extent to which a food causes a rise in blood sugar. The more rapidly a food causes blood sugar to rise, the higher its GI. Conversely, foods that cause blood sugar to rise more slowly, maintain a more stable blood sugar level, and provide a greater sense of satiety have a lower GI. A systematic review of 101 studies, including clinical trials on 8,527 volunteers, found that a low-GI diet can significantly reduce body weight, body fat index, low-density lipoprotein cholesterol, and total cholesterol, demonstrating a moderate weight loss effect. For people with normal blood sugar levels, a GI difference of 20 or more can lead to more significant reductions in body weight and total cholesterol.

[0003] Currently, low-GI breads are primarily made with whole grains and whole grains, supplemented with various non-nutritive sweeteners. While this ensures a low GI, the finished product lacks rise and has a poor taste. Improving the specific volume and mouthfeel characteristics of this type of bread has long been an industry challenge. Furthermore, traditional freshly made bread has a short shelf life, typically only 1-3 days, with whole-wheat bread lasting slightly longer, but only about 3 days. Expired bread breeds bacteria, and moldy bread can also contain high levels of aflatoxin, a carcinogen. Consumers often find themselves in the awkward position of having their bread expire before they've even finished it, feeling torn between eating it or not. Allulose, a natural sweetener, is not only low in energy but also has a sweetness pulse similar to sucrose, resulting in a soft, delicate taste. Products made with it have a long shelf life, and yeast can utilize it to ferment and produce gas, forming a network structure in the bread and triggering the Maillard reaction. Therefore, it can perfectly replace sucrose, making it particularly suitable for baked goods.

[0004] Recent studies have shown that allulose has a certain physiological effect on reducing body fat content, which is positively correlated with dosage. It can enhance postprandial fat oxidation in healthy individuals, making it a novel sweetener that can maintain body weight and enhance energy metabolism. Other clinical studies have shown that additional intake of allulose can significantly lower blood sugar levels in patients with type 2 diabetes.

[0005] Based on current industry hot issues and the excellent functions of allulose, the inventors of this case conducted in-depth research on the above-mentioned issues and technical difficulties, which led to the emergence of this case. Summary of the Invention

[0006] The present invention aims to provide a whole-wheat bread with low GI, long shelf life, good taste and fat-reducing and blood sugar-lowering functions. Another object of the present invention is to provide a processing method for the bread.

[0007] The present invention is achieved by comprising the following raw materials, by weight: 120-150 parts whole wheat flour, 1-20 parts wheat flour, 5-12 parts gluten, 2-4 parts yeast, 15-25 parts whole egg liquid, 15-25 parts butter, 10-20 parts milk powder, 0.5-1.5 parts of a compound improver, 0.5-1.2 parts of salt, 2-4 parts of glucose, 4-6 parts of psicose, 0.2-0.5 parts of trehalose, 5-10 parts of a compound sweetener composition, and 68-85 parts of water. The compound sweetener composition comprises one or more of psicose, erythritol, glucose and steviol glycosides, mogroside, sucralose, and maltitol. The compound improver comprises one or more of monoglycerol fatty acid esters, diglycerol fatty acid esters, hemicellulase, calcium carbonate, sodium alginate, vitamin C, soy protein, α-amylase, and xylanase.

[0008] As a preferred embodiment of the present invention, the fineness of the whole wheat flour is 80-120 mesh.

[0009] As a preferred embodiment of the present invention, the whisker is made by grinding and sieving whole-grain wheat, and retains the same proportion of endosperm, bran and germ as the original whole-grain wheat.

[0010] As a preferred embodiment of the present invention, in order to give full play to the material properties and improve uniformity, the best choice should be a co-crystal of one or more of allulose, erythritol, glucose and steviol glycosides, mogrosides, sucralose, and maltitol.

[0011] The present invention is achieved by providing a method for preparing low GI whole wheat bread, comprising the following steps:

[0012] Step 1: Activate yeast: Weigh 2-4 parts of glucose, 4-6 parts of allulose, 0.2-0.5 parts of trehalose, and 0.5-0.7 parts of salt and dissolve them in 68-85 parts of 42°C warm water. Stir thoroughly and then add 2-4 parts of yeast. Activate for 20-26 minutes.

[0013] Step 2: Preparation of a composite sweetener composition: Control the particle size of allulose, erythritol, glucose, glucose, and maltitol seed crystals to 180-240 mesh. Cultivate the crystals in three steps, cooling at a rate of 0.25-0.35°C / h, starting at 55-65°C and ending at 15-20°C. Finally, centrifuge, wash, and dry to obtain co-crystals. The resulting co-crystals are thoroughly mixed with steviol glycosides, mogrosides, and sucralose, and then passed through a 60-mesh sieve to obtain the composite sweetener composition.

[0014] Step 3: Mixing the powders: Excluding the raw materials used in step 1, the remaining powders are mixed evenly with the compound sweetener composition obtained in step 2 according to the above-mentioned ratios of various powders.

[0015] Step 4. Prepare the liquid: Beat the eggs and microwave the butter until dissolved.

[0016] Step 5: Make the dough: Combine the yeast solution from Step 1 with the egg and flour mixture from Step 3 and beat on low speed until a clumping mass forms. Then, beat on high speed until the dough expands. Add the liquid butter and beat on low speed until the butter is fully absorbed. Continue beating on high speed until the dough is soft, smooth, and does not stick to the pan.

[0017] Step 6. Dough proofing: Proofing procedure: temperature 38°C, humidity 80-90% RH, proofing time 60-80 minutes.

[0018] Step 7. Exhaust and divide: Knead the dough after proofing until all large bubbles are exhausted, divide it into 50g portions, roll them into balls, cover with plastic wrap, and relax at room temperature for 15 minutes.

[0019] Step 8, fermentation: fermentation procedures, temperature 38 ° C, humidity 80-85% RH, fermentation time 60-80 min.

[0020] Step 9. Baking: Baking procedure: upper fire 160-180℃, lower fire 170-190℃, baking time 12-17 minutes, remove from the oven and let cool.

[0021] As a preferred embodiment of the present invention, the low GI whole wheat bread for improving the shelf life of freshly made bread and the preparation method thereof, the liquid butter temperature is between 25-35°C.

[0022] As a preferred implementation method of the present invention, the low GI whole wheat bread and its preparation method for improving the shelf life of freshly made bread are described. Low speed refers to a rotation speed of 100-120r / min, and high speed refers to a rotation speed of 200-250r / min.

[0023] As a preferred embodiment of the present invention, the low GI whole wheat bread for improving the shelf life of freshly made bread and the preparation method thereof, the temperature of the dough during mixing and leaving the dough vat should be between 26-28°C.

[0024] As a preferred embodiment of the present invention, the low GI whole wheat bread and its preparation method for improving the shelf life of freshly made bread are cooled and controlled under the following conditions: temperature 22-26°C, RH 75%, air flow rate 3-4m / s

[0025] Compared with the prior art, the whole wheat bread and the preparation method thereof of the present invention have the following characteristics:

[0026] By optimizing the product formula and yeast fermentation conditions, a product with good taste and specific volume is obtained, which has a long shelf life and a GI value below 37.

[0027] The bread of the present invention uses allulose as the primary sweetener and filler. Allulose not only replaces sucrose for bulking and produces a good Maillard color, but also exhibits fermentability, providing a good texture and preventing the bread from being too firm. Furthermore, allulose has a low energy value and has a physiological effect on reducing body fat. It can also significantly lower blood sugar levels in patients with type 2 diabetes, making it an excellent product for fitness, weight loss, and patients with type 2 diabetes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 To study the effect of whole wheat flour addition on the comprehensive score of whole wheat bread;

[0029] Figure 2 To study the effect of high-gluten flour addition on the comprehensive score of whole wheat bread;

[0030] Figure 3 The effect of heating temperature on the comprehensive score of whole wheat bread;

[0031] Figure 4 The effect of heating temperature on the comprehensive score of whole wheat bread;

[0032] Figure 5 The effect of glucose addition on the overall score of whole wheat bread;

[0033] Figure 6 To study the effect of proofing time on the overall score of whole wheat bread;

[0034] Figure 7 The effect of fermentation time on the comprehensive score of whole wheat bread;

[0035] Figure 8 To study the effect of allulose addition on the comprehensive score of whole wheat bread;

[0036] Figure 9 To study the effect of gluten addition on the comprehensive score of whole wheat bread;

[0037] Figure 10The response surface of the interaction between high-gluten flour addition and allulose addition on the comprehensive score of whole wheat bread was analyzed.

[0038] Figure 11 This is a contour map of the interaction between the amount of high-gluten flour and the amount of allulose added on the comprehensive score of whole wheat bread;

[0039] Figure 12 The response surface of the interaction between high-gluten flour and gluten addition on the comprehensive score of whole-wheat bread was presented.

[0040] Figure 13 This is a contour map of the interaction between the amount of high-gluten flour added and the amount of gluten added on the comprehensive score of whole-wheat bread;

[0041] Figure 14 The response surface of the interaction between the amount of allulose added and the amount of gluten added on the comprehensive score of whole wheat bread was presented;

[0042] Figure 15 This is a contour map showing the interaction effect of allulose addition and gluten addition on the comprehensive score of whole wheat bread. DETAILED DESCRIPTION

[0043] In order to further explain the technical points of the present invention, the following is an elaboration with reference to specific embodiments. The embodiments described in this patent are only used to explain the present invention and are not used to limit the present invention.

[0044] Example 1

[0045] The following raw materials were weighed by weight: 128 parts of whole wheat flour, 15 parts of wheat flour, 8 parts of gluten, 2 parts of yeast, 15 parts of whole egg liquid, 18 parts of butter, 11 parts of milk powder, 0.6 parts of compound improver, 0.8 parts of salt, 3 parts of glucose, 5 parts of allulose, 0.3 parts of trehalose, 7 parts of compound sweetener composition, and 73 parts of water; the glucose is the part without compound sweetener composition, and the allulose is the part without compound sweetener composition.

[0046] The raw materials of the compound sweetener composition are as follows by weight: 18 parts of allulose, 98.32 parts of erythritol, 1.57 parts of steviol glycosides, 1.14 parts of mogrosides, and 0.29 parts of sucralose;

[0047] The compound improver comprises, by weight, 50.8 parts of mono- and diglycerol fatty acid esters, 5.8 parts of hemicellulase, 6.1 parts of calcium carbonate, 4.7 parts of sodium alginate, and 3.5 parts of vitamin C.

[0048] Step 1. Activation of yeast: Weigh 3 parts of glucose, 5 parts of allulose, 0.3 parts of trehalose, and 0.5 parts of salt and dissolve them in 73 parts of warm water at 42°C. Stir thoroughly and then add 2 parts of yeast. The activation time is 20 minutes.

[0049] Step 2: Preparation of a composite sweetener composition: The particle size of allulose, erythritol, and seed crystals was controlled to be between 180 and 240 mesh. The crystals were grown by cooling in three steps, with a cooling rate of 0.3°C / h, a starting temperature of 60°C, and an ending temperature of 15°C. Finally, the co-crystals were centrifuged, washed, and dried. The resulting co-crystals were thoroughly mixed with 1.57 parts of steviol glycosides, 1.14 parts of mogroside, and 0.29 parts of sucralose, and the mixture was passed through a 60-mesh sieve to obtain the composite sweetener composition.

[0050] Step 3, mixing powders: deduct the raw materials used in step 1, and mix the remaining powders with the composite sweetener composition obtained in step 2 in the same proportion as in Example 1.

[0051] Step 4. Prepare the liquid: Beat the eggs and microwave the butter until dissolved.

[0052] Step 6: Make the dough: Combine the yeast solution from step 1, the egg mixture from step 4, and the flour from step 3 and beat. Beat at low speed until a dough forms. Then, beat at high speed until a rough dough forms that can be stretched by hand. Add the liquid butter and beat at low speed until the butter is fully absorbed. Continue beating at high speed until the dough is soft and smooth, forming a "glove-like" dough.

[0053] Step 6, dough proofing: proofing procedure, temperature 38°C, humidity 90% RH, proofing time 70 minutes.

[0054] Step 7: Exhaust and divide: Knead the dough until all large bubbles are exhausted, divide it into 50g portions, roll them into balls, cover with plastic wrap, and relax at room temperature for 15 minutes.

[0055] Step 8, fermentation: fermentation procedure, temperature 38 ° C, humidity 85% RH, fermentation time 65 min.

[0056] Step 9. Baking: Baking procedure: upper fire 170℃, lower fire 180℃, baking time 14 minutes, remove from the oven and let cool.

[0057] Example 2

[0058] The following raw materials were weighed by weight: 135 parts whole wheat flour, 10 parts wheat flour, 8 parts gluten, 2.5 parts yeast, 17 parts whole egg liquid, 20 parts butter, 11 parts milk powder, 0.5 parts compound improver, 0.9 parts salt, 2 parts glucose, 4 parts psicose, 0.2 parts trehalose, 10 parts compound sweetener, and 71 parts water. The compound sweetener combination comprises the following raw materials by weight: 18 parts psicose, 36 parts glucose, 60 parts erythritol, 1.0 part steviol glycoside, 0.8 part mogroside, 0.2 part sucralose, and 28 parts maltitol. The glucose does not comprise part of the compound sweetener composition, and the psicose does not comprise part of the compound sweetener composition.

[0059] The compound improver comprises, by weight, 52 parts of mono- and diglycerol fatty acid esters, 6 parts of hemicellulase, 5.1 parts of sodium alginate, 4 parts of vitamin C, 15 parts of soy protein, and 5 parts of α-amylase.

[0060] Step 10, yeast activation: Weigh 2 parts of glucose, 4 parts of allulose, 0.2 parts of trehalose, and 0.67 parts of salt and dissolve them in 71 parts of 42°C warm water. Stir thoroughly and then add 2.5 parts of yeast. The activation time is 22 minutes.

[0061] Step 11, Preparation of a Compound Sweetener Composition: The seed crystal size of allulose, erythritol, glucose, and maltitol was controlled to be 180-240 mesh, and the crystals were grown by cooling in three steps, wherein the cooling rate was controlled at 0.25°C / h, the starting temperature was 63°C, and the ending temperature was 18°C. Finally, co-crystals were obtained by centrifugation, washing, and drying. The obtained co-crystals were thoroughly mixed with 1.0 part of steviol glycosides, 0.8 part of mogrosides, and 0.2 part of sucralose, and the mixture was passed through a 60-mesh sieve to obtain a compound sweetener composition.

[0062] Step 12: Mixing powders: Excluding the raw materials used in step 10, the remaining powders are mixed evenly with the composite sweetener composition obtained in step 11 according to the ratio of various powders required in Example 2.

[0063] Step 13. Prepare the liquid: Beat the eggs and microwave the butter until dissolved.

[0064] Step 14: Dough Preparation: Combine the yeast solution from step 10, the whole egg liquid from step 13, and the powder from step 12 and beat. Beat at low speed until a clumping mass forms. Then, beat at high speed until a rough dough forms that can be stretched by hand. Add the liquid butter and beat at low speed until the butter is fully absorbed. Continue beating at high speed until the dough is soft and smooth, which is determined by the ability to pull out a "glove-like" dough.

[0065] Step 15, dough proofing: proofing procedure, temperature 38°C, humidity 85% RH, proofing time 75 minutes.

[0066] Step 16, exhaust and divide: Knead the dough after proofing until all large bubbles are exhausted, divide it into 50g / portion of dough, roll it into balls, cover with plastic wrap, and relax at room temperature for 15 minutes.

[0067] Step 17, fermentation: fermentation procedure, temperature 38°C, humidity 85% RH, fermentation time 70 min.

[0068] Step 18. Baking: Baking procedure: upper fire 160℃, lower fire 170℃, baking time 16 minutes, remove from the oven and let cool.

[0069] Example 3

[0070] The following ingredients were weighed out by weight: 125 parts whole wheat flour, 15 parts wheat flour, 6 parts gluten, 2 parts yeast, 18 parts whole egg liquid, 18 parts butter, 12 parts milk powder, 0.5 parts compound improver, 1 part salt, 2.5 parts glucose, 6 parts psicose, 0.3 parts trehalose, 8 parts compound sweetener, and 70 parts water. The compound sweetener composition comprises the following ingredients by weight: 23 parts psicose, 20 parts glucose, 75 parts erythritol, 1.75 parts steviol glycosides, 0.38 parts mogroside, 0.38 parts sucralose, and 10 parts maltitol. The compound improver comprises the following ingredients by weight: 45 parts mono- and diglycerol fatty acid esters, 4 parts vitamin C, 18 parts soy protein, 7.5 parts α-amylase, and 7 parts xylanase. The glucose and psicose are not included in the compound sweetener composition, and the compound sweetener composition is not included in the compound sweetener composition.

[0071] Step 19, yeast activation: Weigh 2.5 parts of glucose, 6 parts of allulose, 0.3 parts of trehalose, and 0.55 parts of salt and dissolve them in 70 parts of 42°C warm water. Stir thoroughly and then add 2 parts of yeast. The activation time is 24 minutes.

[0072] Step 20: Preparation of a composite sweetener composition: The seed crystals of psicose, erythritol, glucose, and maltitol were controlled to have a particle size of 180-240 mesh. The crystals were grown by cooling in three steps, with a cooling rate of 0.3°C / h, a starting temperature of 65°C, and an ending temperature of 20°C. Finally, the co-crystals were centrifuged, washed, and dried. The resulting co-crystals were thoroughly mixed with 1.75 parts of steviol glycosides, 0.38 parts of mogroside, and 0.38 parts of sucralose, and the mixture was passed through a 60-mesh sieve to obtain the composite sweetener composition.

[0073] Step 21, mixing powders: excluding the raw materials used in step 19, the remaining powders are mixed evenly with the composite sweetener composition obtained in step 20 according to the ratio of various powders required in Example 3.

[0074] Step 22, liquid material preparation: Beat the eggs and microwave the butter until dissolved.

[0075] Step 23: Dough Preparation: Combine the yeast solution from step 19, the whole egg liquid from step 22, and the powder from step 21 and beat. Beat at low speed until a dough forms. Then, beat at high speed until a rough dough forms that can be stretched by hand. Add liquid butter and beat at low speed until the butter is fully absorbed. Continue beating at high speed until the dough is soft and smooth, which is determined when a "glove-like" dough can be pulled out.

[0076] Step 24, dough proofing: proofing procedure, temperature 38°C, humidity 90% RH, proofing time 65 min.

[0077] Step 25, exhaust and divide: Knead the dough after proofing until all large bubbles are exhausted, divide it into 50g / portion of dough, roll it into balls, cover with plastic wrap, and relax at room temperature for 15 minutes.

[0078] Step 26, fermentation: fermentation procedure, temperature 38°C, humidity 85% RH, fermentation time 65 min.

[0079] Step 27, baking: baking procedure, upper fire 165 ℃, lower fire 175 ℃, baking time 15.5 minutes, remove from the oven and let cool.

[0080] Comparative Example 1

[0081] The following ingredients were weighed by weight: 128 parts whole wheat flour, 15 parts wheat flour, 8 parts gluten, 2 parts yeast, 15 parts whole egg liquid, 18 parts butter, 11 parts milk powder, 0.6 parts compound improver, 0.8 parts salt, 3 parts glucose (excluding the compound sweetener composition), 5 parts psicose (excluding the compound sweetener composition), 7 parts compound sweetener, and 73 parts water. The compound sweetener composition ingredients, by weight, were: 18 parts psicose, 98.32 parts erythritol, 1.57 parts steviol glycosides, 1.14 parts mogrosides, and 0.29 parts sucralose. The compound improver, by weight, was: 50.8 parts mono- and diglycerides of fatty acids, 5.8 parts hemicellulase, 6.1 parts calcium carbonate, 4.7 parts sodium alginate, and 3.5 parts vitamin C. The main difference between this comparative example and the example is that the yeast is only activated with ordinary warm water, and the other conditions are basically controlled to be the same.

[0082] Step 28: Weigh 2 parts of yeast and add 73 parts of 40°C warm water to activate for 10 minutes.

[0083] Step 29, Preparation of a Composite Sweetener Composition: The seed crystals of psicose, erythritol, glucose, and maltitol were controlled to have a particle size of 180-240 mesh. The crystals were grown by cooling in three steps, with the cooling rate controlled at 0.3°C / h, starting at 60°C and ending at 15°C. Finally, the co-crystals were centrifuged, washed, and dried. The resulting co-crystals were thoroughly mixed with 3 parts of glucose, 5 parts of psicose, 0.85 parts of steviol glycosides, 0.62 parts of mogrosides, and 0.15 parts of sucralose, and the mixture was passed through a 60-mesh sieve to obtain the composite sweetener composition.

[0084] Step 30, mixing powders: excluding the raw materials used in step 28, the remaining raw materials are mixed uniformly with the composite sweetener composition obtained in step 29 according to the proportions of raw materials in Example 1.

[0085] Step 31, liquid material preparation: Beat the eggs and microwave the butter until dissolved.

[0086] Step 32: Dough Preparation: Combine the yeast solution from step 28, the whole egg liquid from step 31, and the powder from step 30, then beat at low speed until a dough forms. Then, beat at high speed until a rough dough forms that can be stretched by hand. Add liquid butter and beat at low speed until the butter is fully absorbed. Continue beating at high speed until the dough is soft and smooth, which is determined when a "glove-like" dough can be formed.

[0087] Step 33, dough proofing: proofing procedure, temperature 38°C, humidity 90% RH, proofing time 70 min.

[0088] Step 34, exhaust and divide: Knead the dough after proofing until all large bubbles are exhausted, divide it into 50g / portion of dough, roll it into balls, cover with plastic wrap, and relax at room temperature for 15 minutes.

[0089] Step 35, fermentation: fermentation procedure, temperature 38°C, humidity 85% RH, fermentation time 65 min.

[0090] Step 36, baking: baking rules, upper fire 170 ℃, lower fire 180 ℃, baking time 14 minutes, take out of the oven, and let it cool

[0091] Comparative Example 2

[0092] The following raw materials were weighed by weight: 135 parts whole wheat flour, 10 parts wheat flour, 8 parts gluten, 2.5 parts yeast, 17 parts whole egg liquid, 20 parts butter, 11 parts milk powder, 0.5 parts compound improver, 0.9 parts salt, 2 parts glucose (excluding the compound sweetener composition), 4 parts allulose (excluding the compound sweetener composition), 0.3 parts trehalose, 10 parts compound sweetener, and 71 parts water. The compound sweetener combination comprises the following raw materials in the following weight ratios: 18 parts allulose, 36 parts glucose, 60 parts erythritol, 1.0 parts steviol glycosides, 0.8 parts mogrosides, 0.2 parts sucralose, and 28 parts maltitol.

[0093] The compound improver comprises, by weight, 52 parts of mono- and diglycerol fatty acid esters, 6 parts of hemicellulase, 5.1 parts of sodium alginate, 4 parts of vitamin C, 15 parts of soy protein, and 5 parts of α-amylase. The main difference between this comparative example and the example is that the compound sweetener composition is not subjected to a co-crystallization process; the remaining conditions are essentially the same.

[0094] Step 37, yeast activation: Weigh 2 parts of glucose, 4 parts of allulose, 0.3 parts of trehalose, and 0.67 parts of salt and dissolve them in 71 parts of 42°C warm water. Stir thoroughly and then add 2.5 parts of yeast. The activation time is 22 minutes.

[0095] Step 38, mixing powders: Excluding the raw materials used in step 37, the remaining powders (including the compound sweetener composition) are mixed uniformly according to the requirements of Example 2.

[0096] Step 39, liquid material preparation: Beat the eggs and microwave the butter until dissolved.

[0097] Step 40: Dough Preparation: Combine the yeast solution from step 37, the whole egg liquid from step 39, and the powder from step 38, then beat at low speed until a dough forms. Then, beat at high speed until a rough dough forms that can be stretched by hand. Add liquid butter and beat at low speed until the butter is fully absorbed. Continue beating at high speed until the dough is soft and smooth, which is determined when a "glove-like" dough can be formed.

[0098] Step 40, dough proofing: proofing procedure, temperature 38°C, humidity 85% RH, proofing time 75 min.

[0099] Step 41, exhaust and divide: Knead the dough after proofing until all large bubbles are exhausted, divide it into 50g / portion of dough, roll it into balls, cover with plastic wrap, and relax at room temperature for 15 minutes.

[0100] Step 42, fermentation: fermentation procedure, temperature 38°C, humidity 85% RH, fermentation time 70 min.

[0101] Step 43, baking: baking procedure, upper fire 160 ℃, lower fire 170 ℃, baking time 16 minutes, remove from the oven and let cool.

[0102] Comparative Example 3

[0103] The following ingredients were weighed by weight: 140 parts wheat flour, 5 parts gluten, 2 parts yeast, 20 parts whole egg liquid, 20 parts butter, 10 parts milk powder, 1 part salt, 30 parts sucrose, and 70 parts water. This is a common recipe for commercially available soft bread.

[0104] Step 44, yeast activation: Weigh 2 parts of yeast and add 70 parts of 40°C warm water for activation for 10 minutes.

[0105] Step 45, mixing of powders: mixing the various powders in the proportions required in Comparative Example 3.

[0106] Step 46, liquid material preparation: Beat the eggs and microwave the butter until dissolved.

[0107] Step 47, Dough Preparation: Combine the yeast solution from step 44, the whole egg liquid from step 46, and the powder from step 45, then beat. Beat at low speed until a clumping mass forms. Then, beat at high speed until a rough dough forms that can be stretched by hand. Add liquid butter and beat at low speed until the butter is fully absorbed. Continue beating at high speed until the dough is soft and smooth, which is determined when a "glove-like" dough can be formed.

[0108] Step 48, dough proofing: proofing procedure, temperature 38°C, humidity 90% RH, proofing time 70 min.

[0109] Step 49, exhaust and divide: Knead the dough after proofing until all large bubbles are exhausted, divide it into 50g / portion of dough, roll it into balls, cover with plastic wrap, and relax at room temperature for 15 minutes.

[0110] Step 50, fermentation: fermentation procedure, temperature 38°C, humidity 85% RH, fermentation time 70 min.

[0111] Step 51, baking: baking procedure, upper fire 170 ℃, lower fire 180 ℃, baking time 14 minutes, remove from the oven and let cool.

[0112] Comparative Example 4

[0113] Weigh the following ingredients by weight: 100 parts whole wheat flour, 40 parts wheat flour, 6 parts gluten, 2 parts yeast, 18 parts whole egg liquid, 18 parts butter, 12 parts milk powder, 0.5 parts compound improver, 1 part salt, and 70 parts water. This example uses a common commercially available low-GI bread.

[0114] Step 52, activation of yeast: Weigh 2 parts of yeast and add 70 parts of 40°C warm water for activation for 10 minutes.

[0115] Step 53, mixing of powders: mixing various powders in the ratio required in Comparative Example 4 uniformly.

[0116] Step 54, liquid material preparation: Beat the eggs and microwave the butter until dissolved.

[0117] Step 55, Dough Preparation: Combine the yeast solution from step 52, the whole egg liquid from step 54, and the powder from step 53 and beat. Beat at low speed until a clumping mass forms. Then, beat at high speed until a rough dough forms that can be stretched by hand. Add liquid butter and beat at low speed until the butter is fully absorbed. Continue beating at high speed until the dough is soft and smooth, which is determined when a "glove-like" dough can be formed.

[0118] Step 56, dough proofing: proofing procedure, temperature 38°C, humidity 90% RH, proofing time 60 min.

[0119] Step 57, exhaust and divide: Knead the dough after proofing until all large bubbles are exhausted, divide it into 50g / portion of dough, roll it into balls, cover with plastic wrap, and relax at room temperature for 15 minutes.

[0120] Step 58, fermentation: fermentation procedure, temperature 38°C, humidity 85%RH, fermentation time 70min.

[0121] Step 59, baking: baking procedure, upper fire 170℃, lower fire 180℃, baking time 14 minutes, remove from the oven and let cool.

[0122] The bread prepared above was subjected to sensory and performance tests:

[0123] Specific volume test:

[0124] 1. Weigh the bread to be tested to an accuracy of 0.1g.

[0125] 2. Using the bread specific volume measuring device, first cover the bottom box, open the top box lid and insert plate, put the filler into the top box to the zero line of the ruler, cover the top cover, and repeatedly turn it upside down several times to adjust the amount of filler added to the zero line of the ruler; when measuring, first put the filler upside down in the top box, turn off the insert plate switch, open the bottom box lid, put the bread to be measured, cover the bottom cover, pull open the insert plate to let the filler fall naturally, and read the filler scale on the ruler, which is the measured volume of the bread. Calculate the specific volume of bread according to the following formula (1):

[0126] ρ=V / M

[0127] Where: ρ, specific volume, mL / g;

[0128] V, volume, mL;

[0129] m, mass, g.

[0130] The sensory evaluation rules and indicators are shown in Table 1:

[0131] Table 1 Sensory evaluation details

[0132]

[0133]

[0134] The in vitro eGI value determination method is based on Chinese patent CN 114431270 A. The rapid in vitro starch digestion method is used to determine the digestibility of starch. The details are as follows:

[0135] ① Mix 0.2 g of sample bread (crushed in a grinder and passed through an 80-mesh sieve) with 2.0 mL of deionized water and soak at 37°C for 20 min.

[0136] ② The sample suspension was treated with α-amylase from porcine pancreas, followed by the addition of pepsin and incubation at 37°C in a shaking water bath for 30 min. The digestion solution was neutralized with 0.02 mol / L NaOH and then adjusted to pH 6.0 with sodium acetate buffer. Pancreatic enzyme and amyloglucosidase were suspended in the mixture and incubated at 37°C. During this process, glucose concentration was measured at 30, 60, 90, 120, and 150 h. The hydrolysis rate (HR) of the sample was then calculated according to formula (1).

[0137] HR=G×(7 / 0.1)×(1.1 / 0.1)*(1 / 1000)×(100%

[0138] / DM)×(162 / 180)(1)

[0139] Where: G is the mass of glucose / μg; 7 / 0.1 = volume correction at different hydrolysis times;

[0140] 1.1 / 0.1 is the GOPOD step volume correction;

[0141] 1 / 1000 is the conversion of glucose from micrograms to milligrams;

[0142] DM is the dry weight of the sample / mg;

[0143] 162 / 180 is the conversion of free D-glucose obtained from starch to dehydrated starch.

[0144] ③ With the hydrolysis time as the horizontal axis and HR as the vertical axis, a hydrolysis rate curve was drawn. The area under the hydrolysis rate curve (AUC) was calculated using Origin software, and the hydrolysis index (HI, %) of the sample was calculated according to formula (2).

[0145] HI=AUC1 / AUC0×100% (2)

[0146] Where: AUC1 is the area under the curve of starch hydrolysis rate in the sample;

[0147] AUC0 = area under the hydrolysis rate curve of standard white bread.

[0148] ④Finally, the estimated glycemic index eGI is obtained according to formula (3).

[0149] eGI=0.862HI+8.1981 (3)

[0150] Shelf life testing:

[0151] Cool the bread to room temperature and cut into 0.5 cm thick slices. Place the sample bread slices in a ziplock bag disinfected with 75% alcohol and store at room temperature. Determine the total colony count using agar plate culture according to GB 4789.2-2016, "National Food Safety Standard: Determination of Total Colony Counts in Food Microbiological Examination."

[0152] If the total colony count is greater than 104 CFU / g, it is considered to have exceeded the shelf life.

[0153]

[0154] The examples are prepared in accordance with the preferred embodiment of the invention. Comparative Example 1 is yeast activated with only ordinary warm water, Comparative Example 2 is a compound sweetener composition that has not been co-crystallized, Comparative Example 3 is a commercially available soft bread, and Comparative Example 4 is a commercially available low-GI bread. Although the commercially available soft bread in Comparative Example 3 has a good taste, its GI value is too high, making it a high-GI food. The present invention has a longer shelf life and a lower GI value without significantly compromising the taste. The present invention is significantly superior to the commercially available low-GI bread in Comparative Example 4 in terms of specific volume, GI, sensory quality, and shelf life. Comparative Example 1 is inferior to the example in terms of specific volume, indicating that the activation method in the example can improve the fermentation ability of yeast to a certain extent. Comparative Example 2 has a greater decline in sensory quality and specific volume compared to the example, indicating that the addition of the compound sweetener composition in a co-crystallized manner significantly improves the overall uniformity and quality of the product. In summary, the present invention can improve the shelf life of the product and ensure the fluffiness and taste of the bread while ensuring a low GI through the rational combination of raw materials, the construction of a compound sweetener composition and a special yeast activation method, providing a low GI and good-tasting option for people who are losing weight, exercising, etc.

[0155] In order to better optimize the best formula of the whole wheat bread of the present invention, and to guide the reasonable fine-tuning of the formula in actual production. On the basis of the single-factor experiment, the optimal conditions of each factor were obtained. The single-factor results are shown in the attached figure. Then, 9 factors affecting the quality of bread were selected for investigation through the Plackett-Burman (PB) test, namely the amount of whole wheat flour added, the amount of high-gluten flour added, the upper fire temperature, the lower fire temperature, the amount of glucose added, the proofing time, the fermentation time, the amount of allulose added, and the amount of gluten added. The comprehensive score of 50% sensory + 50% (55-GI value) (Y) was used as the response value, and a PB experimental design (N=12) was carried out, with the low level being recorded as -1 and the high level being recorded as +1. In addition, J is a virtual factor used to investigate the experimental error. The factors and levels of the PB experimental design are shown in the table below.

[0156]

[0157] A main effects analysis was conducted on the PB design. Three significant factors identified in the experiment—the amount of high-gluten flour (A), the amount of allulose (B), and the amount of wheat gluten (C)—were selected. A response surface design (RSD) was employed using a central composite Box-Behnken (BBD) design. A, B, and C were used as independent variables, and the response value was a composite score (50% sensory perception + 50% (55-GI value)) (Y). The factors and levels in the central composite design are shown in the table below. Data were analyzed and processed using Design-Expert.

[0158]

[0159] The results of the response surface experiment are shown in the following table:

[0160]

[0161]

[0162] Perform multiple regression fitting on the data in the above table to obtain the fitting model of the equation:

[0163] Y=65.1+0.82A+0.71B+1.25C+0.95AB+0.23AC+0.31BC-1.09A 2 -0.

[0164] 69B 2 -26C 2

[0165] Where, Y, comprehensive score, points; A, amount of high-gluten flour added, g; B, amount of allulose added; C, amount of gluten added, g.

[0166] The results of variance analysis are shown in the following table:

[0167]

[0168]

[0169] Note: * indicates significant effect, P < 0.05; ** indicates extremely significant effect, P < 0.01.

[0170] The most significant items are: A, C, A 2 ; Significant items are: B, AB; Insignificant items are: AC, BC, B 2 、C 2 The model's F=23.25, P=0.0002, indicating that the model is significant; the lack-of-fit term F=0.78, P=0.5657>0.05, is not significant, indicating that the model is reasonable and applicable; R 2 =0.9297 indicates an obvious linear relationship, R 2 Adj =0.8392, which generally proves that the response surface effect has a high degree of fit with the experiment, and the experimental results can be analyzed and predicted.

[0171] The response surface and contour lines of three significant influencing factors: high-gluten flour addition (A), allulose addition (B), and gluten addition (C) are shown in Figure 2. Figure 1 As shown. The response surfaces are all convex with an opening downward, indicating the presence of a maximum response. The steepness of the response surface and the shape of the contour lines reflect the strength of the interaction between the factors. A steep response surface indicates a significant effect, whereas a steeper one indicates an insignificant effect. Contour lines that are close to an ellipse indicate a significant interaction between the two factors; those that are close to a circle indicate an insignificant interaction. The results show that the interaction between the amount of high-gluten flour added (A) and the amount of allulose added (B) has a significant effect on the response surface value, while the interaction between the amount of high-gluten flour added (A) and gluten (C), and the interaction between the amount of allulose added (B) and gluten added (C) has no significant effect on the response value.

[0172] According to Design-Expert software analysis, the theoretically optimal conditions for the highest overall score are: 17.2g of high-gluten flour, 18g of allulose, and 9.73g of gluten. Under these conditions, the predicted overall score is 66.9885. The measured value is 67.12, very close to the predicted value, indicating that the fitting results can truly reflect the impact of various factors on the overall score of whole-wheat bread and have practical application value.

[0173] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any appropriate changes or modifications made by anyone with similar ideas should be deemed to be within the patent scope of the present invention.

Claims

1. A low-GI whole-wheat bread for improving the shelf life of freshly made bread, comprising the following ingredients, in parts by weight: 120-150 parts of whole-wheat flour, 1-20 parts of wheat flour, 5-12 parts of gluten, 2-4 parts of yeast, 15-25 parts of whole egg liquid, 15-25 parts of butter, 10-20 parts of milk powder, 0.5-1.5 parts of a compound improver, 0.5-1.2 parts of salt, 3-8 parts of glucose, 0.2-0.5 parts of trehalose, 17-35 parts of a compound sweetener composition, and 68-85 parts of water, wherein the glucose is the portion not containing the compound sweetener composition; The compound improver is one or more of mono- and diglycerol fatty acid esters, hemicellulase, calcium carbonate, sodium alginate, vitamin C, soy protein, α-amylase, and xylanase; The yeast is subjected to an activation step, and the yeast activation step comprises: Weigh 2-4 parts of glucose, 4-6 parts of allulose, 0.2-0.5 parts of trehalose, and 0.5-0.7 parts of salt and dissolve them in 68-85 parts of 42°C warm water. Stir thoroughly and add 2-4 parts of yeast. Activate for 20-26 minutes. The compound sweetener composition is obtained by the following preparation steps: controlling the particle size of allulose, erythritol, maltitol, and glucose seed crystals to 180-240 mesh, cooling and growing the crystals three times, wherein the cooling rate is controlled at 0.25-0.35°C / h, the starting temperature is 55-65°C, and the ending temperature is 15-20°C; finally, co-crystals are obtained by centrifugation, washing, and drying; the obtained co-crystals are fully mixed with steviol glycosides, mogrosides, and sucralose, and the mixture is sieved through a 60-mesh sieve to obtain the compound sweetener composition.

2. The low GI whole wheat bread for increasing the shelf life of freshly made bread according to claim 1, characterized in that: The fineness of whole wheat flour is 80-120 mesh.

3. The low GI whole wheat bread for increasing the shelf life of freshly made bread according to claim 1, wherein: Whole wheat flour must be made by grinding and sieving whole wheat, retaining the same proportions of endosperm, bran and germ as the original whole wheat.

4. A method for preparing low GI whole wheat bread for increasing the shelf life of freshly made bread according to claim 1, characterized in that The following steps are involved: Step 1: Activate the yeast: weigh 2-4 parts of glucose, 4-6 parts of allulose, 0.2-0.5 parts of trehalose, and 0.5-0.7 parts of salt and dissolve them in 68-85 parts of 42°C warm water. Stir thoroughly and then add 2-4 parts of yeast. Activate for 20-26 minutes. Step 2: Preparing a composite sweetener composition: controlling the particle size of allulose, erythritol, maltitol, and glucose seed crystals to 180-240 mesh, cooling and growing the crystals in three steps, wherein the cooling rate is controlled at 0.25-0.35°C / h, the starting temperature is 55-65°C, and the ending temperature is 15-20°C. Finally, co-crystals are obtained by centrifugation, washing, and drying. The obtained co-crystals are thoroughly mixed with steviol glycosides, mogrosides, and sucralose, and the mixture is sieved through a 60-mesh sieve to obtain the composite sweetener composition. Step 3: Mixing the powders: Excluding the raw materials used in step 1, the remaining powders are mixed evenly with the composite sweetener composition obtained in step 2 according to the ratio of various powders required for the whole wheat bread; Step 4: Prepare the liquid: Beat the eggs and microwave the butter until dissolved. Step 5: Dough making: Mix the activated yeast water in step 1 with the whole egg liquid and flour in step 3 and beat them. Beat at low speed until they form a ball, then beat at high speed until the dough expands. Add liquid butter and beat at low speed until the butter is fully absorbed. Continue beating at high speed until the dough is soft, smooth, and does not stick to the pan. Step 6: Dough proofing: Proofing procedure: temperature 38°C, humidity 80%-90% RH, proofing time 60-80 minutes; Step 7: Exhaust and divide: Knead the dough until all large bubbles are exhausted, divide it into 50g portions, roll them into balls, cover with plastic wrap, and relax at room temperature for 15 minutes; Step 8, fermentation: fermentation protocol, temperature 38 ° C, humidity 80%-85% RH, fermentation time 60-80 min; Step 9. Baking: Baking procedure: upper fire 160-180℃, lower fire 170-190℃, baking time 12-17 minutes, remove from the oven and let cool.

5. A method for preparing low GI whole wheat bread for increasing the shelf life of freshly made bread as claimed in claim 4, characterized in that: Liquid butter temperature is between 25℃ and 35℃.

6. A method for preparing low GI whole wheat bread for increasing the shelf life of freshly made bread as claimed in claim 4, characterized in that: The low speed refers to a rotation speed of 100-120 r / min, and the high speed refers to a rotation speed of 200-250 r / min.

7. A method for preparing low GI whole wheat bread for increasing the shelf life of freshly made bread as claimed in claim 4, characterized in that: The temperature of the dough should be between 26-28℃ when mixing and taking it out of the cylinder.

8. A method for preparing low GI whole wheat bread for increasing the shelf life of freshly made bread as claimed in claim 4, characterized in that: The cooling control conditions are: temperature 22-26℃, RH75%, and air flow rate 3-4m / s.

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