CN116172034B

CN116172034B - Low-GI whole wheat bread for improving shelf life of bread and preparation method thereof

Info

Publication number: CN116172034B
Application number: CN202310394549.2A
Authority: CN
Inventors: 曹庆龙; 张静超; 张金祥; 周丽莎
Original assignee: Kangtong Shanghai Biological Research And Development Co ltd
Current assignee: Kangtong Shanghai Biological Research And Development Co ltd
Priority date: 2023-04-13
Filing date: 2023-04-13
Publication date: 2025-08-08
Anticipated expiration: 2043-04-13
Also published as: CN116172034A

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 the bread and is lower than that of common low-GI bread products on the market.

Description

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

Technical Field

The invention relates to the technical field of bread, in particular to low-GI whole wheat bread for improving the shelf life of the bread and a preparation method thereof.

Background

Industry reports indicate that the Chinese baking market in 2020 has a scale of 2510 hundred million yuan and always shows a good rising trend, wherein bread has a large production potential. Most of bread butter and sugar are high in content, and although the requirements of taste are met, the health is affected by frequent eating. In the context of a green and healthy large environment, low sugar and low fat, freshness, natural raw materials, functional health claim to be the product concept that is most attractive to consumers. GI (Glycemic Index) is "glycemic index", abbreviated as "glycemic index". Is an index for reflecting the rising degree of blood sugar of human body caused by food. The more easily the blood glucose is raised, the higher the GI value of the food. Conversely, the food having a slower rise in blood glucose, a more stable blood glucose, and a stronger feeling of fullness has a lower GI value. A system review included 101 studies, and through clinical trials of 8527 volunteers, a low GI diet was found to significantly reduce body weight, body fat index, low density lipoprotein cholesterol and total cholesterol, with some effect on weight loss. For normoglycemic individuals, GI differences of greater than 20 can result in more significant weight and total cholesterol reductions.

The existing bread with low GI mainly uses coarse cereals and coarse grain materials as main materials and various non-nutritive sweeteners as auxiliary materials, and the bread is ensured to have lower GI, but the finished product has insufficient expansion property and poor taste. Solving the specific volume and taste characteristics of the bread is always an industry problem. On the other hand, the shelf life of the traditional bread is short, generally only 1-3d, and the whole wheat bread is slightly long, and only about 3 d. Bacteria can grow after the bread expires, and if the bread is moldy, the bread also contains more aflatoxin and has carcinogenic effect. Consumers often face the embarrassing situation that the purchased bread is out of date when not consumed, and pain is intertwined between eating and not eating. As a natural sweetener, the psicose has low energy value, sweetness time pulse similar to that of cane sugar and soft and fine taste. The product has the characteristic of long shelf life, and the saccharomycete can utilize the saccharomycete to ferment and produce gas to form a bread network structure, and the Maillard reaction can take place, so that the product can perfectly replace the function of sucrose and is particularly suitable for baking food.

Recent researches show that psicose has a certain physiological effect on reducing the fat content of human bodies, is positively correlated with the dosage, can enhance the postprandial fat oxidation of healthy people, and is a novel sweetener capable of maintaining the weight and enhancing the energy metabolism of the human bodies. Additional intake of psicose has also been shown in clinical studies to significantly reduce blood glucose levels in patients with type II diabetes.

Based on the hot spot problem in the current industry and the good function of psicose, the inventor conducts intensive research on the problem and the technical problem, and the scheme is generated.

Disclosure of Invention

The invention aims to provide whole wheat bread with low GI, long shelf life, good taste and lipid-lowering and blood sugar-lowering functions, and another aim of the invention is to provide a processing method of the whole wheat bread.

The invention is realized by the following raw materials, by weight, 120-150 parts of whole wheat flour, 1-20 parts of wheat flour, 5-12 parts of wheat 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 modifier, 0.5-1.2 parts of salt, 2-4 parts of glucose, 4-6 parts of psicose, 0.2-0.5 part of trehalose, 5-10 parts of a compound sweetener composition and 68-85 parts of water. The compound sweetener composition is one or more of psicose, erythritol, glucose, stevioside, mogroside, sucralose and maltitol. The compound modifier is one or more of monoglyceride, diglyceride, hemicellulase, calcium carbonate, sodium alginate, vitamin C, soybean protein, alpha-amylase and xylanase.

As a preferred embodiment of the present invention, the whole wheat flour has a fineness of 80 to 120 mesh.

As a preferred embodiment of the present invention, the said fiber is prepared by grinding and sieving whole wheat, and the endosperm, bran and germ are maintained in the same proportion as the whole wheat.

As a preferred embodiment of the present invention, for fully utilizing the characteristics of the material while improving the uniformity, a co-crystal of psicose, erythritol, glucose with one or more of stevioside, mogroside, sucralose, maltitol is preferably selected.

The invention is realized in such a way that a preparation method of low GI whole wheat bread is provided, comprising the following steps:

Step one, activating yeast, namely weighing 2-4 parts of glucose, 4-6 parts of psicose, 0.2-0.5 part of trehalose and 0.5-0.7 part of salt, dissolving in 68-85 parts of warm water at 42 ℃, fully stirring uniformly, and adding 2-4 parts of yeast, wherein the activation time is 20-26min.

Step two, preparing a compound sweetener composition, namely controlling the seed crystal granularity of psicose, erythritol, glucose and maltitol to be 180-240 meshes, cooling and growing the crystal for three times, wherein the cooling rate is controlled to be 0.25-0.35 ℃ per hour, the initial temperature is 55-65 ℃ and the end temperature is 15-20 ℃, and finally preparing a eutectic through centrifugation, washing and drying. The obtained eutectic is fully and evenly mixed with stevioside, mogroside and sucralose, and the mixture is sieved by a 60-mesh sieve, thus obtaining the compound sweetener composition.

And thirdly, mixing the powder, namely subtracting the raw materials used in the first step, and uniformly mixing the rest of the powder with the compound sweetener composition obtained in the second step according to the proportion of various powder in the requirements.

And step four, preparing liquid material, namely beating whole eggs, and heating butter by microwave until the whole eggs are dissolved for later use.

And step five, dough making, namely mixing the yeast water in the step one with the whole egg liquid and the powder in the step three, stirring at a low speed until the whole egg liquid and the powder are agglomerated, and stirring at a high speed to form dough expansion stage. Adding liquid butter, and stirring at low speed until butter is fully absorbed. The dough is continuously whipped at a high speed until the dough is soft and smooth and is not stuck to a cylinder.

Step six, dough proofing, namely proofing the dough at 38 ℃ with humidity of 80-90% RH for 60-80min.

And seventh, exhausting and cutting, namely kneading the proofed dough until the big bubbles are exhausted, cutting the dough into 50 g/part of dough, rounding, covering a preservative film, and relaxing at room temperature for 15min.

Step eight, fermentation procedure, fermentation time is 60-80min, wherein the temperature is 38 ℃, the humidity is 80-85% RH.

Step nine, baking, namely baking the materials, namely heating the materials to 160-180 ℃ and heating the materials to 170-190 ℃ for 12-17 minutes, discharging the materials, and airing the materials.

As a preferred implementation method of the invention, the low GI whole wheat bread for improving the shelf life of the bread and the preparation method thereof have the liquid butter temperature of 25-35 ℃.

As a preferred implementation method of the invention, the low GI whole wheat bread for improving the shelf life of the bread and the preparation method thereof have the advantages that the low speed means the rotating speed is 100-120r/min, and the high speed means 200-250r/min.

As a preferred embodiment of the invention, the low GI whole wheat bread for improving the shelf life of the bread and the preparation method thereof, the temperature of the dough during stirring and discharging is 26-28 ℃.

As a preferred implementation method of the invention, the low GI whole wheat bread for improving the shelf life of the bread and the preparation method thereof have the cooling control conditions that the temperature is 22-26 ℃ and the RH is 75%, and the air flow rate is 3-4m/s

Compared with the prior art, the whole wheat bread and the preparation method thereof have the following characteristics:

By optimizing the product formula and the yeast fermentation conditions, the product with good taste and specific volume is obtained, and the product has longer shelf life and GI value lower than 37.

The bread disclosed by the invention adopts the psicose as the main sweetener and the filler, so that the psicose not only can replace sucrose to play a role in filling and has good color and luster of Maillard reaction, but also has certain fermentation performance, and good texture is provided for the bread, so that the product is not excessively firm. Meanwhile, the psicose has low energy value, has a certain physiological effect on reducing the fat content of human bodies, can obviously reduce the blood sugar level of patients with type II diabetes, and is an excellent product for body building, weight losing and type II diabetes patients.

Drawings

FIG. 1 is a graph showing the effect of whole wheat flour addition on whole wheat bread composite score;

FIG. 2 is a graph showing the effect of high gluten flour addition on overall whole wheat bread score;

FIG. 3 is a graph showing the effect of the light-off temperature on the overall score of whole wheat bread;

FIG. 4 is a graph showing the effect of lower fire temperature on overall whole wheat bread score;

FIG. 5 is a graph showing the effect of glucose addition on overall whole wheat bread score;

FIG. 6 is an effect of proofing time on whole wheat bread composite score;

FIG. 7 is a graph showing the effect of fermentation time on whole wheat bread composite score;

FIG. 8 is a graph showing the effect of allose addition on whole wheat bread composite score;

FIG. 9 is a graph showing the effect of gluten addition on overall whole wheat bread score;

FIG. 10 is a response surface of interaction of high gluten flour addition and psicose addition on overall score of whole wheat bread;

FIG. 11 is a contour plot of the effect of interaction of high gluten flour addition and psicose addition on overall score of whole wheat bread;

FIG. 12 is a response surface of the effect of the interaction of the high gluten flour addition and the gluten flour addition on the overall score of whole wheat bread;

FIG. 13 is a contour plot of the effect of the interaction of the high gluten flour addition and the gluten addition on the overall score of whole wheat bread;

FIG. 14 is a response surface of interaction of allose addition with gluten addition on overall whole wheat bread score;

FIG. 15 is a contour plot of the effect of interaction of allose addition and gluten addition on overall whole wheat bread score.

Detailed Description

In order to further explain the technical gist of the present invention, the following is explained in connection with specific embodiments. The examples described in this patent are for illustration only and are not intended to limit the invention.

Example 1

The raw materials are 128 parts of whole wheat flour, 15 parts of wheat flour, 8 parts of wheat gluten, 2 parts of yeast, 15 parts of whole egg liquid, 18 parts of butter, 11 parts of milk powder, 0.6 part of compound modifier, 0.8 part of salt, 3 parts of glucose, 5 parts of psicose, 0.3 part of trehalose, 7 parts of compound sweetener composition and 73 parts of water, wherein the glucose is a part without the compound sweetener composition, and the psicose is a part without the compound sweetener composition

The compound sweetener composition comprises 18 parts of psicose, 98.32 parts of erythritol, 1.57 parts of stevioside, 1.14 parts of mogroside and 0.29 part of sucralose according to the weight ratio;

the compound modifier comprises, by weight, 50.8 parts of mono-and diglyceride 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.

Step 1, activating yeast, namely weighing 3 parts of glucose, 5 parts of psicose, 0.3 part of trehalose and 0.5 part of salt, dissolving in 73 parts of warm water at 42 ℃, fully stirring uniformly, and then adding 2 parts of yeast, wherein the activation time is 20min.

And 2, preparing a compound sweetener composition, namely controlling the granularity of psicose, erythritol and seed crystals to be 180-240 meshes, cooling and crystallizing for three times, controlling the cooling rate to be 0.3 ℃ per hour, controlling the initial temperature to be 60 ℃ and the final temperature to be 15 ℃, and finally preparing the eutectic through centrifugation, washing and drying. The obtained eutectic is fully and evenly mixed with 1.57 parts of stevioside, 1.14 parts of mogroside and 0.29 part of sucralose, and the mixture is sieved by a 60-mesh sieve, thus obtaining the compound sweetener composition.

And 3, mixing the powder, namely subtracting the raw materials used in the step 1, and uniformly mixing various powder with the compound sweetener composition obtained in the step 2 according to the raw material proportion in the embodiment 1.

And 4, preparing liquid materials, namely beating whole eggs, and heating butter by microwave until the butter is dissolved for later use.

And 6, dough making, namely mixing the yeast water in the step 1, the whole egg liquid in the step 4 and the powder in the step 3, and stirring at a low speed until the whole egg liquid and the powder are agglomerated, and stirring at a high speed until the whole egg liquid and the powder can be manually spread to form a coarse film. Adding liquid butter, and stirring at low speed until butter is fully absorbed. And continuously beating at a high speed until the dough is soft and smooth, and judging that the end point is that the glove film can be pulled out.

And 6, dough proofing, namely proofing the dough at 38 ℃ with humidity of 90% RH for 70min.

And 7, exhausting and cutting, namely kneading the proofed dough until the big bubbles are exhausted, cutting the dough into 50 g/part of dough, rounding, covering a preservative film, and relaxing at room temperature for 15min.

And 8, fermenting, namely fermenting at 38 ℃ with humidity of 85% RH for 65min.

And 9, baking, namely baking the materials, namely heating the materials to 170 ℃ and heating the materials to 180 ℃ for 14 minutes, discharging the materials, and airing the materials.

Example 2

The raw materials are 135 parts of whole wheat flour, 10 parts of wheat flour, 8 parts of wheat gluten, 2.5 parts of yeast, 17 parts of whole egg liquid, 20 parts of butter, 11 parts of milk powder, 0.5 part of compound modifier, 0.9 part of salt, 2 parts of glucose, 4 parts of psicose, 0.2 part of trehalose, 10 parts of compound sweetener and 71 parts of water. The compound sweetener composition comprises, by weight, 18 parts of psicose, 36 parts of glucose, 60 parts of erythritol, 1.0 part of stevioside, 0.8 part of mogroside, 0.2 part of sucralose and 28 parts of maltitol, wherein the glucose does not contain a compound sweetener composition part, and the psicose does not contain a compound sweetener composition part.

The compound modifier comprises, by weight, 52 parts of mono-and diglyceride fatty acid esters, 6 parts of hemicellulase, 5.1 parts of sodium alginate, 4 parts of vitamin C, 15 parts of soybean protein and 5 parts of alpha-amylase.

Step 10, activating yeast, namely weighing 2 parts of glucose, 4 parts of psicose, 0.2 part of trehalose and 0.67 part of salt, dissolving in 71 parts of warm water at 42 ℃, fully stirring uniformly, and then adding 2.5 parts of yeast, wherein the activation time is 22min.

And 11, preparing a compound sweetener composition, namely controlling the seed crystal granularity of psicose, erythritol, glucose and maltitol to be 180-240 meshes, cooling and crystallizing for three times, controlling the cooling rate to be 0.25 ℃ per hour, controlling the starting temperature to be 63 ℃ and the ending temperature to be 18 ℃, and finally preparing a co-crystal by centrifuging, washing and drying, fully and uniformly mixing the obtained co-crystal with 1.0 part of stevioside, 0.8 part of mogroside and 0.2 part of sucralose, and sieving the mixture with a 60-mesh sieve to obtain the compound sweetener composition.

And step 12, mixing the powder, namely subtracting the raw materials used in the step 10, and uniformly mixing the rest of the compound sweetener composition obtained in the step 11 according to the various powder proportions required in the example 2.

And 13, preparing liquid materials, namely beating whole eggs, and heating butter by microwave until the butter is dissolved for later use.

And 14, dough making, namely mixing the yeast water in the step 10, the whole egg liquid in the step 13 and the powder in the step 12, and stirring at a low speed until the yeast water and the whole egg liquid are agglomerated, and stirring at a high speed until the yeast water and the whole egg liquid can be manually spread to form a coarse film. Adding liquid butter, and stirring at low speed until butter is fully absorbed. And continuously beating at a high speed until the dough is soft and smooth, and judging that the end point is that the glove film can be pulled out.

And 15, dough proofing, namely proofing the dough at 38 ℃ with humidity of 85% RH for 75min.

And 16, exhausting and cutting, namely kneading the proofed dough until the big bubbles are exhausted, cutting the dough into 50 g/part of dough, rounding, covering a preservative film, and relaxing at room temperature for 15min.

And 17, fermenting, namely fermenting at 38 ℃ with humidity of 85% RH for 70min.

And 18, baking, namely baking the materials at 160 ℃ on fire and 170 ℃ on fire for 16min, discharging from the furnace, and airing.

Example 3

The raw materials are 125 parts of whole wheat flour, 15 parts of wheat flour, 6 parts of wheat gluten, 2 parts of yeast, 18 parts of whole egg liquid, 18 parts of butter, 12 parts of milk powder, 0.5 part of compound modifier, 1 part of salt, 2.5 parts of glucose, 6 parts of psicose, 0.3 part of trehalose, 8 parts of compound sweetener and 70 parts of water. The compound sweetener composition comprises 23 parts of psicose, 20 parts of glucose, 75 parts of erythritol, 1.75 parts of stevioside, 0.38 part of mogroside, 0.38 part of sucralose and 10 parts of maltitol. The compound modifier comprises, by weight, 45 parts of mono-and diglyceride fatty acid esters, 4 parts of vitamin C, 18 parts of soy protein, 7.5 parts of alpha-amylase and 7 parts of xylanase, wherein glucose does not contain a compound sweetener composition part, and psicose does not contain a compound sweetener composition part.

And 19, activating yeast, namely weighing 2.5 parts of glucose, 6 parts of psicose, 0.3 part of trehalose and 0.55 part of salt, dissolving in 70 parts of warm water at 42 ℃, fully stirring uniformly, and adding 2 parts of yeast, wherein the activation time is 24 minutes.

Step 20, preparing a compound sweetener composition, namely controlling the seed crystal granularity of psicose, erythritol, glucose and maltitol to be 180-240 meshes, cooling and crystallizing for three times, controlling the cooling rate to be 0.3 ℃ per hour, controlling the initial temperature to be 65 ℃ and the end temperature to be 20 ℃, and finally preparing a eutectic through centrifugation, washing and drying. The obtained co-crystal is fully and uniformly mixed with 1.75 parts of stevioside, 0.38 parts of mogroside and 0.38 parts of sucralose, and the mixture is sieved by a 60-mesh sieve, so that the compound sweetener composition is obtained.

And step 21, mixing the powder, namely subtracting the raw materials used in the step 19, and uniformly mixing the rest of the compound sweetener composition obtained in the step 20 according to the various powder proportions required in the example 3.

Step 22, preparing liquid material, namely beating whole eggs, and heating butter by microwave until the butter is dissolved for later use.

Step 23, dough making, namely mixing the yeast water in the step 19, the whole egg liquid in the step 22 and the powder in the step 21, and stirring at a low speed until the yeast water and the whole egg liquid are agglomerated, and stirring at a high speed until the yeast water and the whole egg liquid can be manually spread to form a coarse film. Adding liquid butter, and stirring at low speed until butter is fully absorbed. And continuously beating at a high speed until the dough is soft and smooth, and judging that the end point is that the glove film can be pulled out.

And 24, dough proofing, namely proofing the dough at 38 ℃ with humidity of 90% RH for 65min.

And 25, exhausting and cutting, namely kneading the proofed dough until the big bubbles are exhausted, cutting the dough into 50 g/part of dough, rounding, covering a preservative film, and relaxing at room temperature for 15min.

And 26, fermenting, namely fermenting at 38 ℃ with humidity of 85% RH for 65min.

And step 27, baking, namely baking the materials at 165 ℃ on the fire and 175 ℃ on the fire for 15.5min, discharging the materials from the furnace, and airing the materials.

Comparative example 1

The raw materials are 128 parts of whole wheat flour, 15 parts of wheat flour, 8 parts of wheat gluten, 2 parts of yeast, 15 parts of whole egg liquid, 18 parts of butter, 11 parts of milk powder, 0.6 part of compound modifier, 0.8 part of salt, 3 parts of glucose (without a compound sweetener composition part), 5 parts of psicose (without a compound sweetener composition part), 7 parts of compound sweetener and 73 parts of water. The compound sweetener composition comprises, by weight, 18 parts of psicose, 98.32 parts of erythritol, 1.57 parts of stevioside, 1.14 parts of mogroside and 0.29 part of sucralose. The compound modifier comprises, by weight, 50.8 parts of mono-and diglyceride 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. The main difference between this comparative example and the examples is that the yeast is only activated by ordinary warm water, and the other conditions are basically controlled to be identical.

Step 28, weighing 2 parts of yeast, and adding 73 parts of warm water at 40 ℃ for activation for 10min.

And 29, preparing a compound sweetener composition, namely controlling the seed crystal granularity of psicose, erythritol, glucose and maltitol to be 180-240 meshes, cooling and crystallizing for three times, controlling the cooling rate to be 0.3 ℃ per hour, controlling the initial temperature to be 60 ℃ and the end temperature to be 15 ℃, and finally preparing a eutectic through centrifugation, washing and drying. The obtained eutectic is fully and evenly mixed with 3 parts of glucose, 5 parts of psicose, 0.85 parts of stevioside, 0.62 parts of mogroside and 0.15 parts of sucralose, and the mixture is sieved by a 60-mesh sieve, thus obtaining the compound sweetener composition.

Step 30, mixing the powder, namely subtracting the raw materials used in the step 28, and uniformly mixing various powder with the compound sweetener composition obtained in the step 29 according to the raw material proportion in the embodiment 1.

Step 31, preparing liquid material, namely beating whole eggs, and heating butter by microwave until the butter is dissolved for later use.

Step 32, dough making, namely mixing the yeast water in the step 28, the whole egg liquid in the step 31 and the powder in the step 30, and stirring at a low speed until the whole egg liquid and the powder are agglomerated, and stirring at a high speed until the whole egg liquid and the powder are hand-opened to form a coarse film. Adding liquid butter, and stirring at low speed until butter is fully absorbed. And continuously beating at a high speed until the dough is soft and smooth, and judging that the end point is that the glove film can be pulled out.

And 33, dough proofing, namely proofing the dough at 38 ℃ with humidity of 90% RH for 70min.

And 34, exhausting and cutting, namely kneading the proofed dough until the big bubbles are exhausted, cutting the dough into 50 g/part of dough, rounding, covering a preservative film, and relaxing at room temperature for 15min.

And 35, fermenting, namely fermenting at 38 ℃ with humidity of 85% RH for 65min.

Step 36, baking, namely baking the materials, namely heating the materials to 170 ℃ and heating the materials to 180 ℃ for 14 minutes, discharging the materials from the furnace, and airing the materials

Comparative example 2

The raw materials are 135 parts of whole wheat flour, 10 parts of wheat flour, 8 parts of wheat gluten, 2.5 parts of yeast, 17 parts of whole egg liquid, 20 parts of butter, 11 parts of milk powder, 0.5 part of compound modifier, 0.9 part of salt, 2 parts of glucose (without a compound sweetener composition part), 4 parts of psicose (without a compound sweetener composition part), 0.3 part of trehalose, 10 parts of compound sweetener and 71 parts of water. The compound sweetener composition is prepared from 18 parts by weight of psicose, 36 parts by weight of glucose, 60 parts by weight of erythritol, 1.0 part by weight of stevioside, 0.8 part by weight of mogroside, 0.2 part by weight of sucralose and 28 parts by weight of maltitol.

The compound modifier comprises, by weight, 52 parts of mono-and diglyceride fatty acid esters, 6 parts of hemicellulase, 5.1 parts of sodium alginate, 4 parts of vitamin C, 15 parts of soybean protein and 5 parts of alpha-amylase. The main difference between this comparative example and the examples is that the formulated sweetener composition is not subjected to co-crystallization and the remaining conditions are substantially controlled to be identical.

Step 37, activating yeast, namely weighing 2 parts of glucose, 4 parts of psicose, 0.3 part of trehalose and 0.67 part of salt, dissolving in 71 parts of warm water at 42 ℃, fully stirring uniformly, and then adding 2.5 parts of yeast, wherein the activation time is 22min.

Step 38, mixing of the powders, except for the raw materials used in step 37, the remainder was mixed uniformly as required in example 2 for various powders (containing the formulated sweetener composition).

Step 39, preparing liquid material, namely beating whole eggs, and heating butter by microwave until the butter is dissolved for later use.

Step 40, dough making, namely mixing the yeast water in the step 37 with the whole egg liquid in the step 39 and the powder in the step 38, and beating, wherein the whole egg liquid and the powder are stirred at a low speed until the whole egg liquid and the powder are agglomerated, and then beating at a high speed until the whole egg liquid and the powder are hand-opened to form a coarse film. Adding liquid butter, and stirring at low speed until butter is fully absorbed. And continuously beating at a high speed until the dough is soft and smooth, and judging that the end point is that the glove film can be pulled out.

And 40, dough proofing, namely proofing the dough at 38 ℃ with humidity of 85% RH for 75min.

And 41, exhausting and cutting, namely kneading the proofed dough until the big bubbles are exhausted, cutting the dough into 50 g/part of dough, rounding, covering a preservative film, and relaxing at room temperature for 15min.

And 42, fermenting, namely fermenting at 38 ℃ with humidity of 85% RH for 70min.

And 43, baking, namely baking the materials at 160 ℃ on fire and 170 ℃ on fire for 16min, discharging from the furnace, and airing.

Comparative example 3

The raw materials are 140 parts of wheat flour, 5 parts of wheat gluten, 2 parts of yeast, 20 parts of whole egg liquid, 20 parts of butter, 10 parts of milk powder, 1 part of salt, 30 parts of sucrose and 70 parts of water. This example is a common formulation for commercially available soft breads.

And 44, activating yeast, namely weighing 2 parts of yeast, and adding 70 parts of warm water at 40 ℃ for activating for 10 minutes.

Step 45, mixing the powder materials, namely uniformly mixing the powder materials according to the proportion required by the comparative example 3.

Step 46, preparing liquid material, namely beating whole eggs, and heating butter by microwave until the butter is dissolved for later use.

Step 47, dough making, namely mixing the yeast water in step 44, the whole egg liquid in step 46 and the powder in step 45, and stirring at a low speed until the yeast water and the whole egg liquid are agglomerated, and stirring at a high speed until the yeast water and the powder can be stretched by hands to form a coarse film. Adding liquid butter, and stirring at low speed until butter is fully absorbed. And continuously beating at a high speed until the dough is soft and smooth, and judging that the end point is that the glove film can be pulled out.

And 48, dough proofing, namely proofing the dough at 38 ℃ with humidity of 90% RH for 70min.

And 49, exhausting and cutting, namely kneading the proofed dough until the big bubbles are exhausted, cutting the dough into 50 g/part of dough, rounding, covering a preservative film, and relaxing at room temperature for 15min.

And 50, fermenting, namely fermenting at 38 ℃ with humidity of 85% RH for 70min.

And 51, baking, namely baking the materials, namely heating the materials to 170 ℃ and heating the materials to 180 ℃ for 14 minutes, discharging the materials, and airing the materials.

Comparative example 4

The raw materials are 100 parts of whole wheat flour, 40 parts of wheat flour, 6 parts of wheat gluten, 2 parts of yeast, 18 parts of whole egg liquid, 18 parts of butter, 12 parts of milk powder, 0.5 part of compound modifier, 1 part of salt and 70 parts of water. This example is a commercially available common low GI bread.

And 52, activating yeast, namely weighing 2 parts of yeast, and adding 70 parts of warm water at 40 ℃ for activating for 10 minutes.

Step 53, mixing the powder materials, namely uniformly mixing the powder materials according to the proportion required by the comparative example 4.

And 54, preparing liquid material, namely beating whole eggs, and heating butter by microwave until the butter is dissolved for later use.

Step 55, dough making, namely mixing the yeast water in the step 52, the whole egg liquid in the step 54 and the powder in the step 53, and stirring at a low speed until the yeast water and the whole egg liquid are agglomerated, and stirring at a high speed until the yeast water and the whole egg liquid can be manually spread to form a coarse film. Adding liquid butter, and stirring at low speed until butter is fully absorbed. And continuously beating at a high speed until the dough is soft and smooth, and judging that the end point is that the glove film can be pulled out.

And 56, dough proofing, namely proofing the dough at 38 ℃ with humidity of 90% RH for 60min.

And 57, exhausting and cutting, namely kneading the proofed dough until the big bubbles are exhausted, cutting the dough into 50 g/part of dough, rounding, covering a preservative film, and relaxing at room temperature for 15min.

And 58, fermenting, namely fermenting at 38 ℃ with humidity of 85% RH for 70min.

Step 59, baking, namely baking the materials, namely heating the materials to 170 ℃ and heating the materials to 180 ℃ for 14 minutes, discharging the materials from the furnace, and airing the materials.

The bread prepared above was subjected to sensory and performance testing:

specific volume test:

1. The bread quality to be measured is weighed to the nearest 0.1g.

2. When in measurement, firstly, the filling material is placed in the top box, the plugboard switch is closed, the bottom box cover is opened, the bread to be measured is put in, the bottom cover is covered, the plugboard is pulled to enable the filling material to naturally fall down, and the scale of the filling material is read out on the scale, thus the measured volume of the bread is obtained. The specific volume of bread was calculated according to the following formula (1):

ρ=V/M

wherein ρ, specific volume, mL/g;

V, volume, mL;

m, mass, g.

Sensory evaluation rules and indexes are shown in table 1:

TABLE 1 sensory evaluation rules

The in vitro eGI value determination method is carried out by referring to Chinese patent CN 114431270A, and the digestion rate of the starch is determined by adopting a rapid in vitro starch digestion method, and is specifically as follows:

① 0.2g of sample bread (crushed by a crusher and passed through an 80 mesh sieve) was mixed with 2.0mL of deionized water and soaked at 37 ℃ for 20min.

② The sample suspension was treated with alpha-amylase from porcine pancreas, then pepsin was added and incubated in an oscillating water bath at 37 ℃ for 30min. The digestate was neutralized with 0.02mol/LNaOH and then adjusted to pH 6.0 with sodium acetate buffer. Pancreatin and amyloglucosidase were suspended in the mixture and incubated at 37 ℃, during which the glucose concentration was determined at 30, 60, 90, 120, 150, respectively. The Hydrolysis Rate (HR) of the sample was then calculated according to equation (1).

HR=G×(7/0.1)×(1.1/0.1)*(1/1000)×(100%

/DM)×(162/180)(1)

Wherein G is glucose mass/μg, 7/0.1 = volume corrected at different hydrolysis times;

1.1/0.1 is GOPOD step volume correction;

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

DM is the dry weight of the sample/mg;

162/180 is the conversion of free D-glucose obtained from starch to the dehydration present in the starch.

③ And (3) drawing a hydrolysis rate curve by taking hydrolysis time as an abscissa and taking HR as an ordinate, solving the area under the hydrolysis rate curve (AUC) by adopting Origin software, and calculating the hydrolysis index (HI,%) of the sample according to a formula (2).

HI=AUC1/AUC0×100% (2)

Wherein AUC1 is the area under the hydrolysis rate curve of starch in the sample;

auc0 = area under standard white bread hydrolysis rate curve.

④ Finally, an estimated glycemic index eGI is obtained according to equation (3).

eGI=0.862HI+8.1981 (3)

Shelf life test:

The bread was cooled to room temperature and sliced into slices of 0.5cm in thickness. Under natural conditions, the sample bread slice is put into a plastic self-sealing bag sterilized by 75% alcohol cotton ball in advance and stored at normal temperature. According to GB 4789.2-2016, "determination of total number of bacterial colonies for food microbiology test national Standard for food safety", the total number of bacterial colonies of a sample is determined by counting and culturing with an agar culture plate.

A colony count greater than 104CFU/g was judged to be beyond shelf life.

The examples were carried out in a preferred manner of the invention, with comparative example 1 being yeast activated only with normal warm water, comparative example 2 being the formulated sweetener composition without co-crystallization, comparative example 3 being a commercially available soft bun and comparative example 4 being a commercially available common low GI bun. Comparative example 3 commercial soft breads, although having a better mouthfeel, have too high a GI value, and are high GI foods, and the invention has a longer shelf life and lower GI value without significantly compromising mouthfeel. The invention is obviously superior to the commercial low GI bread of comparative example 4 in specific volume, GI, sensory quality and shelf life. Comparative example 1 is inferior to the examples in specific volume, indicating that the example activation method can improve the yeast fermentability to some extent. Comparative example 2 showed a greater reduction in sensory quality and a reduction in specific volume compared to example, indicating a higher overall uniformity and quality improvement for the product after co-crystallizing the formulated sweetener composition. In a comprehensive view, the invention can improve the shelf life of the product and ensure the bulk and taste of bread by reasonably collocating the raw materials and constructing the compound sweetener composition and the special yeast activation means on the premise of ensuring low GI, thereby providing a low GI and good taste choice for people such as weight losing, body building and the like.

In order to better optimize the optimal formulation for obtaining the whole wheat bread of the present invention, and to guide the rational fine tuning of the formulation in actual production. On the basis of a single-factor experiment, the optimal conditions of all factors are obtained. The single factor results are shown in the attached drawings. And selecting 9 factors influencing the bread quality for investigation through a Plackett-Burman (PB) test, namely, adding whole wheat flour, high gluten flour, heating temperature, glucose, proofing time, fermentation time, psicose and wheat gluten, and carrying out PB test design (N=12) by taking a comprehensive score of 50% sensory +50% (55-GI value) (Y) as a response value, wherein the low level is minus 1, and the high level is +1. In addition, J is a virtual factor used to investigate experimental errors. The factors and levels of the PB test design are shown in the following table.

And (3) carrying out main effect analysis on PB experimental design, and designing 3 significant factors selected by the test, namely high gluten flour addition (A), psicose addition (B) and gluten addition (C), by adopting a central combined Box-Behnken (BBD) to design a response surface test, taking A, B, C as an independent variable, and taking a comprehensive score of 50% sensory +50% (55-GI value) (Y) as a response value to design a 3-factor 3-level test. The factors and levels in the center combination test protocol are shown in the following table, and data were analyzed using Design-Expert.

The response surface test results are shown in the following table:

Performing multiple regression fitting on the data in the table to obtain a fitting model of the equation:

Y=65.1+0.82A+0.71B+1.25C+0.95AB+0.23AC+0.31BC-1.09A²-0.

69B²-26C²

Wherein, Y, comprehensively scoring, A, high gluten flour adding amount, g, B, psicose adding amount, C, gluten adding amount, g.

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

note that the effect is significant, P <0.05, and P <0.01.

The most significant terms are A, C, A ², B, AB and the less significant terms are AC, BC, B ²、C². The model has obvious f=23.25 and p=0.0002, the mismatching term f=0.78 and p=0.5657 >0.05, the model is not obvious, the model is reasonably applicable, R ² = 0.9297 shows that the linear relation is obvious, R ² _Adj = 0.8392, the overall confirmation of the high fitting degree of the response surface effect and the test is realized, and the test result can be analyzed and predicted.

The response surface and contour lines of the three significant influencing factors, namely the addition amount (A) of the high gluten flour, the addition amount (B) of the psicose and the addition amount (C) of the gluten are shown in figure 1. The response surfaces are all convex with the opening facing downward, indicating that there is a response maximum. The degree of sharpness of the response surface and the shape of the contour reflect the strength of the factor interaction. Steep response surface trend indicates significant effect, otherwise, the effect is not obvious. The contour line is near-elliptical, which indicates significant interaction between the two factors, and near-circular, which indicates insignificant interaction. The results show that the interaction of the high gluten flour addition (A) and the psicose addition (B) has obvious influence on response values, and the interaction of the high gluten flour addition (A) and the wheat gluten (C), the psicose addition (B) and the wheat gluten addition (C) has no obvious influence on response values.

According to Design-Expert software analysis, the theoretical optimal condition with the highest comprehensive score is that the addition amount of the high gluten flour is 17.2g, the addition amount of the psicose is 18g, and the addition amount of the wheat gluten is 9.73g. The predicted composite score under this condition is 66.9885. The actual measurement value is 67.12, is very close to the predicted value, shows that the fitting result can truly reflect the influence of all factors on the comprehensive score of the whole wheat bread, and has practical application value

The above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention, and any suitable variations or modifications of the similar concepts should be regarded as being included in the scope of the invention.

Claims

1. The low GI whole wheat bread for improving the shelf life of the bread comprises, by weight, 120-150 parts of whole wheat flour, 1-20 parts of wheat flour, 5-12 parts of wheat 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 modifier, 0.5-1.2 parts of salt, 3-8 parts of glucose, 0.2-0.5 part of trehalose, 17-35 parts of a compound sweetener composition and 68-85 parts of water, wherein the glucose is a part which does not contain the compound sweetener composition;

The compound modifier is one or more of mono-glycerol fatty acid ester, diglycerol fatty acid ester, hemicellulase, calcium carbonate, sodium alginate, vitamin C, soybean protein, alpha-amylase and xylanase;

The yeast is subjected to an activating step, wherein the activating step comprises the steps of weighing 2-4 parts of glucose, 4-6 parts of psicose, 0.2-0.5 part of trehalose and 0.5-0.7 part of salt, dissolving in 68-85 parts of warm water at 42 ℃, fully stirring uniformly, adding 2-4 parts of yeast, and activating for 20-26min;

The compound sweetener composition is prepared by controlling the granularity of psicose, erythritol, maltitol and glucose seed crystal to be 180-240 meshes, cooling and crystallizing for three times, controlling the cooling rate to be 0.25-0.35 ℃ per hour, controlling the initial temperature to be 55-65 ℃ and the end temperature to be 15-20 ℃, and finally preparing a eutectic crystal by centrifugation, washing and drying, fully and uniformly mixing the obtained eutectic crystal with stevioside, mogroside and sucralose, and sieving the mixture through a 60-mesh sieve to obtain the compound sweetener composition.

2. The low GI whole wheat bread of claim 1, wherein the fineness of the whole wheat flour is 80-120 meshes.

3. The low GI whole wheat bread of claim 1, wherein the whole wheat flour is prepared from whole wheat flour by grinding and sieving, and the same proportion of endosperm, bran and germ as the whole wheat flour is maintained.

4. A method of preparing a low GI whole wheat bread of claim 1, characterized by the steps of:

step one, yeast activation, namely weighing 2-4 parts of glucose, 4-6 parts of psicose, 0.2-0.5 part of trehalose and 0.5-0.7 part of salt to dissolve in 68-85 parts of warm water at 42 ℃, adding 2-4 parts of yeast after fully stirring uniformly, and activating for 20-26min;

Controlling the granularity of psicose, erythritol, maltitol and glucose seed crystal to be 180-240 meshes, cooling and crystallizing for three times, controlling the cooling rate to be 0.25-0.35 ℃ per hour, controlling the initial temperature to be 55-65 ℃ and the end temperature to be 15-20 ℃, and finally preparing a eutectic by centrifugation, washing and drying, fully and uniformly mixing the obtained eutectic with stevioside, mogroside and sucralose, and sieving the mixture with a 60-mesh sieve to obtain the compound sweetener composition;

step three, mixing the powder, namely deducting the raw materials used in the step one, and uniformly mixing the rest of the raw materials with the compound sweetener composition obtained in the step two according to the proportion of various powder required by the whole wheat bread;

Step four, preparing liquid material, namely beating whole eggs, and heating butter by microwave until the butter is dissolved for later use;

Step five, dough making, namely mixing the activated yeast water in the step one with the whole egg liquid and the powder in the step three, stirring at a low speed until the whole egg liquid and the powder are agglomerated, and stirring at a high speed until the whole egg liquid and the powder are agglomerated;

step six, dough proofing, namely proofing the dough at 38 ℃ with humidity of 80-90% RH for 60-80min;

Step seven, air exhaust segmentation, namely kneading the proofed dough until the big bubbles are exhausted, segmenting the dough into 50 g/part of dough, rounding, covering a preservative film, and relaxing for 15 minutes at room temperature;

step eight, fermentation procedure, wherein the temperature is 38 ℃, the humidity is 80-85% RH, and the fermentation time is 60-80min;

5. The method of claim 4, wherein the liquid butter is at a temperature between 25 ℃ and 35 ℃.

6. The method of claim 4, wherein the low speed is 100-120r/min and the high speed is 200-250r/min.

7. The method for preparing low GI whole wheat bread of claim 4, which improves the shelf life of the bread, comprising: the temperature should be between 26-28deg.C during dough stirring and discharging.

8. The method for preparing low GI whole wheat bread with the improved shelf life as claimed in claim 4, wherein the cooling control condition is that the temperature is 22-26 ℃, the RH is 75% and the air flow rate is 3-4m/s.