Preparation of enzymolysis-resistant bread flour and application of enzymolysis-resistant bread flour in whole-wheat bread

Abstract

The invention discloses preparation of enzymolysis-resistant bread flour and application of the enzymolysis-resistant bread flour in whole-wheat bread, and belongs to the field of whole-wheat bread processing. Whole wheat flour is subjected to pullulanase treatment, alpha-1, 6 glucosidic bonds in starch are cut off, the molecular weight of the starch is reduced, and short amylose is obtained, so that formation of resistant starch is promoted. The obtained enzymolysis-resistant bread flour is mixed with improvers such as whole wheat flour, vital gluten, highland barley protein and beta-glucan, and the whole wheat bread is obtained through the steps of dough kneading, fermentation, forming, fermentation, baking and the like. The whole-wheat bread prepared by the method has a relatively low GI value, compared with the whole-wheat bread without the enzymolysis-resistant bread flour, the eGI value of the whole-wheat bread is remarkably reduced, the content of rapidly-digestible starch in the bread is remarkably reduced, and the content of slowly-digestible and resistant starch in the bread is remarkably increased.

Description

Technical Field

[0001] The invention belongs to the field of whole-wheat bread processing, and particularly relates to the preparation of enzymolysis-resistant bread flour and the application of the same in whole-wheat bread. Background Art

[0002] Nowadays, the public's attention to healthy eating continues to rise, especially the choice of food that can effectively prevent chronic diseases. In this context, baked goods made from whole wheat flour, such as whole wheat bread, are favored by more and more consumers. Whole wheat bread refers to bread made from flour ground from whole wheat without removing the bran and germ as the main raw material. Whole wheat bread is rich in dietary fiber, minerals, vitamins, oligosaccharides and other bioactive ingredients, but it has problems such as low specific volume, high hardness, rough texture and high blood sugar level. After fermentation and baking, the starch in whole wheat bread gelatinizes and is easily decomposed and absorbed by digestive enzymes, which quickly increases blood sugar levels, resulting in a high GI value. In addition, the porous gluten network structure in whole wheat bread is also one of the reasons why it is not conducive to consumption by diabetic patients.

[0003] At present, the main ways to improve the glycemic index of whole wheat bread include the selection and processing of raw materials, optimization of processing technology, and exogenous addition of non-starch components such as protein, hydrophilic colloids, and enzymes. However, a single improver does not significantly regulate the glycemic level of bread, and exogenous addition of bread improvers is not suitable for the market application of whole wheat bread.

[0004] Studies have shown that pullulanase can specifically hydrolyze α-1,6 glycosidic bonds in starch, amylopectin and some oligosaccharides to produce short-chain starch. Pullulanase treatment has great application potential in improving starch digestibility, but it is mostly used in pure starch systems from various sources, and its application in flour has not been reported. Summary of the invention

[0005] In view of the existing technical problems, the present invention provides a preparation method of enzymolysis-resistant bread flour and its application in whole-wheat bread. From the perspective of raw materials, the whole-wheat flour is treated with pullulanase to increase the resistant starch content in the whole-wheat flour, thereby forming an enzymolysis-resistant bread flour, so as to solve the problem of high glycemic index of whole-wheat bread from the perspective of raw materials, effectively reduce the starch digestibility of whole-wheat bread, increase the resistant starch content, improve the nutritional value, and improve the taste and quality of whole-wheat bread, so as to supplement the types of food suitable for diabetic patients and effectively solve the problem of single form of low-GI products currently on the market.

[0006] The invention aims to provide a method for preparing enzymolysis-resistant bread crumbs, which comprises the following steps: whole wheat flour is used as a raw material, the whole wheat flour is gelatinized, and then the whole wheat flour is combined with pullulanase for debranching, enzyme inactivation and retrogradation; the obtained complex is washed with deionized water for 2-3 times, dried and sieved to obtain the enzymolysis-resistant bread crumbs.

[0007] In one embodiment, the preparation method specifically comprises mixing whole wheat flour and deionized water at a ratio of 1-2 kg: 10-20 L, boiling the mixture in a boiling water bath for 30-40 min for gelatinization with continuous stirring, adding 50-100 U / g of pullulanase after the whole wheat flour mixture is cooled, stirring the mixture in a 50-70° C. water bath for 6-8 h, boiling the whole wheat flour treated with pullulanase in a boiling water bath for 30-40 min for enzyme inactivation, and then reversing the mixture at a temperature of 0-45° C. for 2-3 days; washing the obtained complex with deionized water for 2-3 times, drying and sieving the mixture to obtain enzymolysis-resistant bread crumbs.

[0008] In one embodiment, the pullulanase activity is 1000 U / g.

[0009] In one embodiment, the preparation method specifically comprises mixing whole wheat flour and deionized water at a ratio of 1 kg:10 L, boiling the mixture in a boiling water bath for 30 minutes for gelatinization, stirring the mixture continuously, adding 60 U / g of pullulanase after the whole wheat flour mixture is cooled, stirring the mixture in a 55°C water bath for 6 hours, boiling the whole wheat flour treated with pullulanase in a boiling water bath for 30 minutes for enzyme inactivation, and then reversing the mixture at 4°C for 2 days; washing the obtained complex twice with deionized water, drying and sieving the mixture to obtain enzymolysis-resistant bread crumbs.

[0010] The second object of the present invention is to provide an enzymolysis-resistant bread crumb prepared by the above method.

[0011] The third object of the present invention is to provide a whole wheat bread, wherein the raw material formula of the whole wheat bread is composed of the following substances in parts by weight: 5-60 parts of the above-mentioned enzymolysis-resistant bread flour, 10-70 parts of whole wheat flour, 10-30 parts of gluten flour, 5-10 parts of highland barley protein, 2-4 parts of β-glucan, 1-3 parts of yeast, and 60-100 parts of water.

[0012] In one embodiment, the raw material formula of the whole wheat bread is composed of the following substances in parts by weight: 7-30 parts of the above-mentioned enzymolysis-resistant bread flour, 50-70 parts of whole wheat flour, 20-30 parts of gluten flour, 7-10 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 80-90 parts of water.

[0013] In one embodiment, the raw material formula of the whole wheat bread is composed of the following substances in parts by weight: 7.2 parts of the above-mentioned enzymolysis-resistant bread flour, 64.8 parts of whole wheat flour, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 83 parts of water.

[0014] In one embodiment, the raw material formula of the whole wheat bread is composed of the following substances in parts by weight: 14.4 parts of the above-mentioned enzymolysis-resistant bread flour, 57.6 parts of whole wheat flour, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 87 parts of water.

[0015] In one embodiment, the raw material formula of the whole wheat bread is composed of the following substances in parts by weight: 21.6 parts of the above-mentioned enzymolysis-resistant bread flour, 50.4 parts of whole wheat flour, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 90.6 parts of water.

[0016] A fourth object of the present invention is to provide a method for preparing whole-wheat bread, the method comprising the following steps:

[0017] (1) Weigh the raw materials according to the above whole wheat bread recipe into a dough mixer and stir for 10-15 minutes to form dough;

[0018] (2) fermenting the dough obtained in step (1) at 30-40° C. for 70-100 min at a proofing humidity of 70%-90%; after fermentation, dividing the dough into pieces and shaping them;

[0019] (3) allowing the dough shaped in step (2) to continue to proof at a temperature of 30-40° C., a proofing time of 30-50 min, and a proofing humidity of 70%-90%;

[0020] (4) placing the dough proofed in step (3) on a baking tray, baking at a temperature of 150-220° C. for 20-30 min, and finally cooling to room temperature to obtain whole wheat bread.

[0021] Beneficial effects:

[0022] (1) The present invention increases the content of amylose in whole wheat flour by performing pullulanase debranching treatment on whole wheat flour, and prepares an enzymolysis-resistant bread flour. The enzymolysis-resistant bread flour is applied to whole wheat bread to reduce the digestibility of whole wheat bread. At the same time, the synergistic effect of various improvers such as gluten flour, highland barley protein, and β-glucan is combined to greatly reduce the digestibility of whole wheat bread while reducing the deterioration of the baking quality and edible quality of whole wheat bread, providing a new idea for preparing whole wheat bread with a low glycemic index.

[0023] (2) Whole wheat bread with a lower GI value can be prepared by using enzyme-resistant bread flour and combining it with a variety of improvers. Compared with whole wheat bread made without enzyme-resistant bread flour, its eGI value is reduced by up to 19.2%, and the content of fast-digestible starch in the bread is significantly reduced, while the content of slowly digestible and resistant starch is significantly increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Cross-sectional views of the crumbs of whole wheat bread prepared in Examples 1 to 3; (a) to (c) are Example 1, Example 2, and Example 3, respectively;

[0025] Figure 2 The starch hydrolysis curve data diagram of whole wheat bread prepared in Examples 1 to 3 and Comparative Examples 1 to 2. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The test method involved in the present invention is:

[0028] 1. Determination of TPA characteristics

[0029] Take a whole wheat bread sample and cut it into slices of about 2 cm thick using a bread slicer. Place them flat on the test table of the texture analyzer. The speed before the test is 3.00 mm / s, the test speed is 1.00 mm / s, and the speed after the test is 5.00 mm / s. The compression ratio is 40% and the interval time is 10 s.

[0030] 2. Determination of glycemic index of simulated digestion in vitro

[0031] Take 0.6g of freeze-dried bread sample (pass through 100 mesh sieve) into a 50ml centrifuge tube, add 10mL of pepsin solution to each test tube, vortex mix, shake in a water bath, add 10ml of sodium acetate buffer, vortex and keep warm at 37℃ for 10min. After the insulation, terminate the reaction with anhydrous ethanol, add mixed enzyme solution (saccharifying enzyme + pancreatin), measure glucose equivalent at 10, 20, 40, 60, 90, 120, 150, 180min, and calculate the starch hydrolysis rate of the sample during digestion based on the measured glucose equivalent.

[0032]

[0033] The hydrolysis area (HI) is the integrated area of ​​the hydrolysis curve, and eGI is calculated according to the following equation:

[0034] eGI=8.198+0.862HI.

[0035] Example 1

[0036] A method for preparing enzymolysis-resistant bread crumbs, the method comprising the following steps:

[0037] Whole wheat flour and deionized water are mixed evenly at a ratio of 1kg:10L, and the mixture is placed in a boiling water bath and boiled for 30 minutes for gelatinization with continuous stirring. After the whole wheat flour mixture is cooled, 60U / g of pullulanase (with a pullulanase activity of 1000U / g) is added, and the mixture is placed in a 55°C water bath and stirred for 6 hours. The whole wheat flour treated with pullulanase is placed in a boiling water bath and boiled for 30 minutes for enzyme inactivation, and then aged at 4°C for 2 days. The obtained complex is washed twice with deionized water, dried and sieved to obtain enzymolysis-resistant bread crumbs.

[0038] A method for preparing whole-wheat bread, comprising the following steps:

[0039] The whole wheat bread is made from the following components in parts by mass: 7.2 parts of enzymolysis-resistant bread flour, 64.8 parts of whole wheat flour, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of beta-glucan, 1.5 parts of yeast, and 83 parts of water, with one part being calculated as 1 g.

[0040] (1) Weigh the raw materials according to the whole wheat bread recipe into a dough mixer and mix for 10 min;

[0041] (2) fermenting the dough obtained in step (1) at 38° C. for 90 min at a proofing humidity of 85%, and after fermentation, dividing the dough into blocks (90 g / block) and shaping the blocks;

[0042] (3) the dough in step (2) is further proofed at a temperature of 38° C., a proofing time of 45 min, and a proofing humidity of 85%;

[0043] (4) placing the dough obtained in step (3) on a baking tray, baking at 200 / 180° C. for 20 min, and finally cooling to room temperature to obtain whole wheat bread.

[0044] Example 2

[0045] Whole-wheat bread is made from the following components in parts by mass: 14.4 parts of enzymolysis-resistant bread flour, 57.6 parts of whole-wheat flour, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 87 parts of water, with one part being calculated as 1 g; except for the raw material formula, the rest are the same as Example 1.

[0046] Example 3

[0047] Whole-wheat bread is made from the following components in parts by mass: 21.6 parts of enzymolysis-resistant bread flour, 50.4 parts of whole-wheat flour, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 90.6 parts of water, with one part being calculated as 1 g; except for the raw material formula, the rest are the same as Example 1.

[0048] Comparative Example 1

[0049] Whole-wheat bread is made from the following components in parts by mass: 100 parts of whole-wheat flour, 1.5 parts of yeast, and 67.8 parts of water, where one part is 1 g; except for the raw material formula, the rest are the same as in Example 1.

[0050] Comparative Example 2

[0051] Whole wheat bread is made from the following components in parts by mass: 72 parts of whole wheat, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 79 parts of water, one part being 1 g; except for the raw material formula, the rest are the same as Example 1.

[0052] Results Analysis

[0053] 1. Determination of the content of amylose in enzymatically resistant bread flour and whole wheat flour. The results are shown in Table 1:

[0054] Table 1 shows the content of amylose in enzymolysis-resistant bread flour and ordinary whole wheat flour

[0055]

[0056] From the results in Table 1, it can be seen that the content of amylose in bread crumbs debranched by pullulanase increases. Pullulanase cuts the α-1,6-glycosidic bonds at the branch points of amylopectin, thereby increasing the content of amylose, and then rearranges to form an organized and compact structure. This rearrangement can help resist hydrolysis by digestive enzymes.

[0057] 2. The texture characteristics of whole wheat bread of the embodiment and the comparative example are shown in Table 2: Table 2 shows the texture characteristics of whole wheat bread of the embodiment and the comparative example.

[0058]

[0059] As can be seen from Table 2, compared with Comparative Example 1, the hardness, stickiness and chewiness of Examples 1-3 increased, and as the amount of enzymolysis-resistant bread flour added increased, the hardness, stickiness and chewiness gradually increased. The cohesion and recovery of Examples 1-3 were lower than those of the comparative example, and as the amount of enzymolysis-resistant bread flour added increased, the cohesion and recovery gradually decreased. The addition of enzymolysis-resistant bread flour had some adverse effects on the quality of the whole bread, and as the amount added increased, the degree of deterioration increased.

[0060] 3. Whole wheat bread quality test, the results are shown in Table 3:

[0061] Table 3 shows the basic qualities of whole wheat bread in the examples and comparative examples.

[0062]

[0063]

[0064] It can be concluded from Table 3 that the increase of enzyme-treated bread flour helps to reduce baking loss. The baking loss of Examples 1, 2, and 3 is reduced by 1.81%, 1.85%, and 2.94% respectively relative to Comparative Example 1; the moisture content increases with the increase of the amount of enzyme-treated bread flour added. When the enzyme-treated bread flour is added, the chromaticity of the whole wheat bread also changes. Examples 1 and 2 increase the brightness, red value, and yellow value of the bread. The brightness of the bread decreases with the increase of the enzyme-treated bread flour, which may be related to the chromaticity of the enzyme-treated bread flour.

[0065] 4. Determination of in vitro starch digestibility of whole wheat bread. The results are shown in Table 4:

[0066] Table 4 shows the results of in vitro starch digestibility of whole wheat bread in the examples and comparative examples.

[0067]

[0068] Figure 2 It shows the starch hydrolysis curves of whole wheat bread obtained in the examples and comparative examples. In the first 10 minutes, the starch in the bread is quickly digested, and the hydrolysis rate of all samples increases rapidly. As the digestion time increases, the digestion rate increases slowly. In comparative example 2, the digested starch content reaches 74% at 120 minutes. The starch digestibility does not increase significantly when the digestion time is further extended. After digestion for 180 minutes, the amount of digested starch is 76.2%. Compared with comparative examples 1 and 2, the hydrolysis rate curves of examples 1-3 are reduced, which shows that the appropriate addition of PF can reduce the starch digestibility of whole wheat bread.

[0069] As shown in Table 4, adding enzyme-treated bread flour can reduce the content of fast-digestible starch (RDS) and slow-digestible starch (SDS) in whole-wheat bread, increase the content of resistant starch (RS), and reduce the eGI value. Compared with Comparative Example 1, Examples 1, 2, and 3 reduce the eGI value of whole-wheat bread by 17.6%, 19.2%, and 14.33%, respectively, among which the effect of reducing the eGI value is best when the addition amount is 20%. The main reason for the inhibition of starch digestion in whole-wheat bread may be that after pullulanase is used to treat bread flour, the content of amylose in bread is increased, the short-chain starch molecules inside are less, and the amylopectin and amylose are arranged more orderly in space, so its RS content is higher. The digestibility of whole-wheat bread starch is also related to the internal embedding effect of non-starch components such as protein on starch. When the amount of enzymolysis-resistant bread flour is too much, this effect will be weakened, resulting in an increase in digestibility.

[0070] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing enzymolysis-resistant bread crumbs, characterized in that: The preparation method comprises the following steps: whole wheat flour is used as raw material, the whole wheat flour is gelatinized, then debranched, inactivated, retrograded, washed, dried and sieved to obtain enzymolysis-resistant bread flour.

2. The preparation method according to claim 1, characterized in that: The preparation method specifically comprises the following steps: uniformly mixing whole wheat flour and deionized water at a ratio of 1-2 kg:10-20 L, placing the mixture in a boiling water bath and boiling for 30-40 minutes for gelatinization, stirring continuously during the process, adding 50-100 U / g of pullulanase after the whole wheat flour mixture is cooled, placing the mixture in a 50-70°C water bath and stirring for 6-8 hours, placing the whole wheat flour treated with pullulanase in a boiling water bath and boiling for 30-40 minutes for inactivating the enzyme, and then reversing the mixture at a temperature of 0-45°C for 2-3 days; washing the obtained complex with deionized water for 2-3 times, drying and sieving, and obtaining enzymolysis-resistant bread crumbs.

3. The preparation method according to any one of claims 1 or 2, characterized in that: The pullulanase activity is 1000 U / g.

4. Enzymolysis-resistant bread crumbs prepared by the preparation method according to any one of claims 1 to 3.

5. A whole wheat bread, characterized in that: The raw material formula of the whole wheat bread consists of the following materials in parts by weight: 5-60 parts of the enzymolysis-resistant bread flour according to claim 4, 10-70 parts of whole wheat flour, 10-30 parts of gluten flour, 5-10 parts of highland barley protein, 2-4 parts of beta-glucan, 1-3 parts of yeast, and 60-100 parts of water.

6. The whole wheat bread according to claim 5, characterized in that: The raw material formula of the whole wheat bread consists of the following materials in parts by weight: 7-30 parts of the enzymolysis-resistant bread flour according to claim 4, 50-70 parts of whole wheat flour, 20-30 parts of gluten flour, 7-10 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 80-90 parts of water.

7. The whole wheat bread according to claim 5, characterized in that: The raw material formula of the whole wheat bread consists of the following materials in parts by weight: 7.2 parts of the enzymolysis-resistant bread flour according to claim 4, 64.8 parts of whole wheat flour, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 83 parts of water.

8. The whole wheat bread according to claim 5, characterized in that: The raw material formula of the whole wheat bread consists of the following substances in parts by weight: 14.4 parts of the enzymolysis-resistant bread flour according to claim 4, 57.6 parts of whole wheat flour, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 87 parts of water.

9. The whole wheat bread according to claim 5, characterized in that: The raw material formula of the whole wheat bread consists of the following materials in parts by weight: 21.6 parts of the enzymolysis-resistant bread flour according to claim 4, 50.4 parts of whole wheat flour, 21 parts of gluten flour, 7 parts of highland barley protein, 2.5 parts of β-glucan, 1.5 parts of yeast, and 90.6 parts of water.

10. A method for preparing whole wheat bread, characterized in that: The method comprises the following steps: (1) Weighing raw materials according to the recipe of whole wheat bread according to any one of claims 5 to 9 into a dough mixer, and stirring for 10-15 minutes to form dough; (2) fermenting the dough obtained in step (1) at 30-40° C. for 70-100 min at a proofing humidity of 70%-90%; after fermentation, dividing the dough into pieces and shaping them; (3) allowing the dough shaped in step (2) to continue to proof at a temperature of 30-40° C., a proofing time of 30-50 min, and a proofing humidity of 70%-90%; (4) placing the dough proofed in step (3) on a baking tray, baking at a temperature of 150-220° C. for 20-30 min, and finally cooling to room temperature to obtain whole wheat bread.

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