Fruit and vegetable enzyme whole wheat bread and preparation method thereof

Abstract

The application provides a fruit and vegetable enzyme whole wheat bread and a preparation method thereof, and the fruit and vegetable enzyme whole wheat bread comprises the following raw materials in parts by weight: whole wheat flour 15-30 parts, high-gluten wheat flour 70-85 parts, fruit and vegetable enzyme 5-12 parts, yeast 0.8-1.8 parts, butter 4-8 parts, white granulated sugar 4-8 parts, egg liquid 8-15 parts, salt 0.3-0.8 parts, gluten 1-4 parts, compound enzyme preparation 0.05-0.5 parts and water 38-52 parts; the compound enzyme preparation comprises xylanase, cellulase and glucose oxidase, and the problems of coarse texture, dry taste, small volume, short shelf life and poor adaptability of fruit and vegetable enzyme to whole wheat dough in the prior art are solved.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a whole wheat bread made with fruit and vegetable enzymes and its preparation method. Background Technology

[0002] Whole wheat bread is made from whole wheat grains, retaining all the grain components such as the endosperm, germ, and bran. It is rich in dietary fiber, B vitamins, minerals, and bioactive components such as phenolic compounds, giving it high nutritional value. However, whole wheat bread generally suffers from problems such as a coarse texture, dry mouthfeel, small size, and short shelf life, significantly reducing consumer acceptance. The main reason for its quality deterioration is that the large amount of insoluble dietary fiber in the bran disrupts the continuity of the gluten network structure, leading to a decrease in the dough's gas-holding capacity and consequently affecting its rising performance during baking.

[0003] Enzymes are mixed fermented liquids made from fresh fruits and vegetables through fermentation by functional microorganisms such as yeast and lactic acid bacteria. They contain abundant nutrients such as sugars, organic acids, minerals, vitamins, phenols, and terpenes, as well as various bioactive substances such as enzymes. In recent years, fruit and vegetable enzymes have been explored for use in improving the quality of whole wheat bread. Studies have shown that their addition can effectively improve the texture, taste, and shelf life of whole wheat bread, demonstrating considerable application potential.

[0004] However, existing technologies for applying fruit and vegetable enzymes to whole wheat bread still have significant shortcomings. First, most fruit and vegetable enzyme products are intended for direct consumption, and their preparation typically involves sterilization, leading to a significant decrease in the number of beneficial microorganisms such as yeast and lactic acid bacteria. Direct application to dough fermentation can easily result in bread that is too hard, lacks flavor, and has a rough texture. Second, current processes often add enzymes directly in liquid form to replace some of the water, but the optimal amount of enzymes added lacks systematic optimization, often requiring repeated adjustments to other formula parameters in practical applications. Third, the synergistic mechanism between fruit and vegetable enzymes and functional components such as gluten, enzyme preparations, and dietary fiber in existing whole wheat bread formulas lacks in-depth and systematic research, making it difficult for each component to achieve its optimal combined effect. Summary of the Invention

[0005] The main objective of this invention is to provide a whole wheat bread infused with fruit and vegetable enzymes and its preparation method, aiming to solve the problems existing in current whole wheat bread technology, such as rough texture, dry taste, small volume, short shelf life, and poor compatibility between fruit and vegetable enzymes and whole wheat dough.

[0006] To achieve the above objectives, the present invention provides a whole wheat bread infused with fruit and vegetable enzymes, comprising the following ingredients by weight: 15-30 parts whole wheat flour, 70-85 parts high-gluten wheat flour, 5-12 parts fruit and vegetable enzyme liquid, 0.8-1.8 parts yeast, 4-8 parts butter, 4-8 parts white sugar, 8-15 parts egg liquid, 0.3-0.8 parts salt, 1-4 parts gluten powder, 0.05-0.5 parts compound enzyme preparation, and 38-52 parts water; The compound enzyme preparation includes xylanase, cellulase and glucose oxidase.

[0007] This invention, through the aforementioned compounding and the introduction of fruit and vegetable enzyme liquid with a compound enzyme preparation containing xylanase, cellulase, and glucose oxidase, as well as functional ingredients such as gluten powder, achieves a systematic improvement in the quality of whole wheat bread. It effectively solves the technical problems of existing whole wheat bread, such as coarse texture, dry mouthfeel, small volume, short shelf life, and poor compatibility between fruit and vegetable enzyme liquid and whole wheat dough. The organic acids, active enzymes, and antibacterial metabolites in the fruit and vegetable enzyme liquid work synergistically with the compound enzyme preparation to effectively soften wheat bran fiber, decompose insoluble dietary fiber, and strengthen the gluten network, thereby significantly improving the dough's gas retention and baking performance. This results in bread with a larger specific volume, a finer and softer internal structure, and a more harmonious natural aroma. Simultaneously, the antibacterial and antioxidant activity of the fruit and vegetable enzyme liquid effectively extends the product's shelf life, while the synergistic effect between the components avoids the use of traditional chemical improvers, meeting clean label requirements. Overall, it achieves a simultaneous improvement in the sensory quality, processing performance, and storage stability of whole wheat bread.

[0008] In some implementations, the total mass of whole wheat flour and high-gluten wheat flour is 100 parts by weight.

[0009] In some embodiments, the mass ratio of the xylanase, the cellulase and the glucose oxidase is 1-3:1-2:1-3 by weight.

[0010] Under the above conditions, xylanase preferentially degrades insoluble xylan in wheat bran, cellulase further decomposes cellulose components, and glucose oxidase strengthens the gluten network through oxidation. The combination of these three effectively reduces the damage to the gluten structure of wheat bran, improves the gas retention and extensibility of the dough, thereby enabling whole wheat bread to have a larger specific volume and a softer texture, and significantly improves the compatibility of fruit and vegetable enzyme liquid with whole wheat dough.

[0011] This invention also provides a method for preparing whole wheat bread infused with fruit and vegetable enzymes, comprising the following steps: S1. Separate the bran from the whole wheat flour, add water to a moisture content of 40-60%, add a compound enzyme preparation for enzymatic hydrolysis, and then treat with moist heat at 95-105℃ for 10-20 minutes to obtain pre-enzymatically hydrolyzed bran liquid. S2. Dry mix high-gluten wheat flour, wheat gluten, white sugar and salt, add the hydrolysate of protein, then mix with compound enzyme preparation, transglutaminase, pre-enzymatic wheat bran liquid, egg liquid, fruit and vegetable enzyme liquid and water, add yeast and continue mixing, then add butter and compound emulsifier and mix until the dough reaches the extended stage. S3. After the dough in the extended stage undergoes a first fermentation, intermediate proofing, and second fermentation, it is then divided, shaped, proofed, baked, and cooled in sequence to obtain fruit and vegetable enzyme whole wheat bread.

[0012] This invention achieves a systematic improvement in the quality of whole wheat bread through the synergistic effect of multiple technologies, including fruit and vegetable enzyme preparation, wheat bran enzymatic hydrolysis pretreatment, transglutaminase cross-linking enhancement, and gradient fermentation and baking processes. This improvement is mainly reflected in the following three aspects: The synergistic effect of fruit and vegetable enzymes: The organic acids in fruit and vegetable enzymes can lower the pH value of dough and effectively soften wheat bran fibers; the active enzymes such as proteases, amylases, and cellulases produced during fermentation can partially decompose the insoluble cellulose in wheat bran, improving the extensibility and processing performance of the dough; the esters in apples and the terpenes in celery, among other aromatic substances, give the product a complex natural aroma that harmonizes with the wheat aroma; at the same time, the organic acids and their metabolites in the enzymes have significant antibacterial activity, which can effectively inhibit the growth of mold and bacteria, thereby extending the shelf life of the product.

[0013] Texture-improving effects of enzymatic pretreatment of wheat bran: Insoluble dietary fiber in wheat bran is the main factor leading to discontinuity in the gluten network structure. Under the synergistic effect of hydrothermal action, xylanase can degrade insoluble xylan in wheat bran into soluble arabinoxylan, reducing the water-holding capacity of wheat bran, causing water to migrate to gluten proteins, and promoting the formation and stability of the gluten network; cellulase further degrades cellulose components, significantly reducing the rough texture of wheat bran. Through enzymatic hydrolysis and the conversion of insoluble fiber to soluble fiber, pre-enzymatically hydrolyzed wheat bran forms a hydrated polysaccharide gel, which can effectively fill and strengthen the gluten network, thereby improving the elasticity and gas-holding capacity of the dough. In addition, multi-strain compound fermentation can also increase the content of polyphenols and soluble dietary fiber in wheat bran, giving whole wheat bread a larger specific volume, a more uniform porosity, and a softer texture.

[0014] Protein cross-linking and strengthening effect of transglutaminase: The introduction of wheat bran into whole wheat dough causes a dilution effect on gluten proteins. Transglutaminase can catalyze the acyl transfer reaction between glutamine residues and lysine residues, forming ε-(γ-glutamyl)-lysine isopeptide bonds between protein molecules, thereby enhancing the spatial stability and gas retention capacity of the gluten network and effectively compensating for the insufficient gluten matrix caused by the addition of wheat bran.

[0015] Specifically, the present invention has the following beneficial effects: (1) Significantly improves the sensory quality of whole wheat bread. After adding fruit and vegetable enzymes, the whole wheat bread has a full shape, a uniform golden color on the surface, a natural wheat aroma and a slight enzyme aroma, and a delicate, soft and elastic internal texture, which completely improves the defects of traditional whole wheat bread, such as rough texture and dry taste.

[0016] (2) Effectively delays bread aging and extends shelf life. The shelf life of traditional whole wheat bread is generally only 3 to 4 days, while the product of this invention can be extended to 7 to 10 days. The organic acids and their metabolites in the enzyme have antibacterial activity, which can effectively inhibit the growth of mold and bacteria; at the same time, the natural antioxidants in the enzyme can delay the oxidation and rancidity of fats, thereby significantly improving the storage stability of the product.

[0017] (3) Improve the processing performance and efficiency of dough. Enzymatic pretreatment converts insoluble fiber in wheat bran into soluble fiber, reduces the damaging effect of wheat bran on the gluten network, improves the water absorption and gas retention of dough, and significantly increases the specific volume and softness of bread.

[0018] (4) Give full play to the synergistic effect among the components. Functional components such as fruit and vegetable enzymes, hydrolyzed wheat bran, gluten powder and compound enzyme preparations work synergistically to enable the product to maintain good texture and flavor characteristics without the addition of chemical modifiers, which is in line with the consumer trend of clean label.

[0019] (5) Gradient fermentation process can promote dough maturation, improve the formation efficiency of gluten network and gas retention capacity; gradient heating baking process helps to form a crisp outer shell and a well-moisturized internal structure, thereby producing a richer aroma.

[0020] In some embodiments, the fruit and vegetable enzyme includes a compound apple and celery enzyme liquid. The preparation method of the fruit and vegetable enzyme includes: juicing apples and celery, filtering the juice, mixing them in a mass ratio of 3-5:1-2, adding pectinase and hydrolyzing at 40-55℃ for 1-3 hours, sterilizing, inoculating with activated lactic acid bacteria, and fermenting at 28-37℃ for 12-48 hours.

[0021] Under the above conditions, fruit and vegetable enzymes can work better with wheat bran pretreatment and compound enzyme preparations to obtain whole wheat bread with soft texture, good flavor and significantly extended shelf life.

[0022] In some embodiments, the raw materials may further include, by weight, one or more of the following: 0.5 to 2 parts of protein hydrolysis products, 0.01 to 0.05 parts of transglutaminase, and 0.1 to 0.5 parts of compound emulsifier.

[0023] Under the above conditions, transglutaminase can catalyze the formation of isopeptide bonds between protein molecules, significantly enhancing the strength and gas retention capacity of the gluten network; protein hydrolysis products can improve the formation efficiency of the gluten network; and compound emulsifiers improve the emulsification state and gas retention of the dough. These three agents, in synergy with fruit and vegetable enzymes, compound enzyme preparations, and wheat bran pretreatment, further compensate for the dilution effect of wheat bran on gluten, effectively increasing the specific volume and softness of whole wheat bread, improving dough processing performance, and thus better solving the problems of small volume and coarse texture in whole wheat bread.

[0024] In some embodiments, the composite emulsifier is composed of sodium stearoyl lactylate and glyceryl monostearate in a mass ratio of 1:1, by weight.

[0025] In some embodiments, in step S1, the moisture content of wheat bran is 45-55%, the enzymatic hydrolysis temperature is 45-55°C, and the enzymatic hydrolysis time is 1-3 hours.

[0026] Under the above conditions, xylanase and cellulase are in their optimal activity range, which can efficiently degrade the insoluble dietary fiber in wheat bran into soluble arabinoxylan and oligosaccharides, significantly reduce the water-holding capacity of wheat bran, promote the migration of water to gluten proteins, thereby strengthening the gluten network structure, improving the gas-holding capacity and extensibility of the dough, and ultimately enabling whole wheat bread to have a larger specific volume and a softer texture, effectively solving the problems of traditional whole wheat bread being small in volume and coarse in texture.

[0027] In some implementations, in step S2, the fruit and vegetable enzyme liquid accounts for 30% to 60% of the total water content in the dough.

[0028] In some embodiments, the mixing conditions in step S2 include: low speed for 2-5 minutes, low speed for 1-2 minutes after adding yeast, and medium speed for 8-15 minutes after adding butter; the dough mixing temperature is 24-28°C.

[0029] In some implementations, the primary fermentation conditions are: temperature 28–32°C, relative humidity 70%–85%, and time 45–90 min.

[0030] In some implementations, ultrasonic-assisted treatment is performed after the first fermentation, with an ultrasonic power of 30-60W and a treatment time of 3-8 minutes.

[0031] In some embodiments, the intermediate proofing conditions include: turning over to degas and then letting it stand at 24–28°C for 15–20 minutes.

[0032] In some implementations, the secondary fermentation conditions are: temperature 32–38°C, relative humidity 80%–90%, and time 30–60 min.

[0033] In some embodiments, the baking step is carried out in one of the following ways: baking at 180-210°C for the top heat and 190-220°C for the bottom heat for 15-25 minutes; or baking at 150-170°C for 5-10 minutes first, and then raising the temperature to 190-220°C for 10-15 minutes.

[0034] In some embodiments, the cooling method includes removing the baked bread and allowing it to cool naturally until the center temperature is ≤35°C. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0037] To further illustrate the present invention, the following examples are provided: Xylanase: Enzyme source: Trichoderma metabolic production; Enzyme activity units: ≥50,000 U / g; Optimal pH: 5.0; Optimal temperature: 50℃; Cellulase: Enzyme source: Trichoderma metabolic production; Enzyme activity units: 50,000 U / g; Optimal pH: 4.8; Optimal temperature: 50℃; Glucose oxidase: Enzyme source: Produced by fermentation of Aspergillus niger; Enzyme activity units: 5000 U / g; Optimal pH: 5.0–5.5; Optimal temperature: 40–50℃ Pectinase: Enzyme source: Produced by fermentation of Aspergillus niger; Enzyme activity units: 30,000 U / g; Optimal pH: 3.5–5.5; Optimal temperature: 40–55℃ Transglutaminase (TG enzyme): Enzyme source: fermentation of *Chaetoceros mogulae*; enzyme activity units: 100 U / g; optimal pH: 6.0; optimal temperature: 50℃; The protein hydrolysate is wheat gluten protein hydrolysate.

[0038] Example 1 This embodiment provides a whole wheat bread infused with fruit and vegetable enzymes, specifically comprising: 20 parts whole wheat flour, 80 parts high-gluten wheat flour, 9 parts fruit and vegetable enzymes, 1.2 parts yeast, 6 parts butter, 6 parts white sugar, 12 parts egg liquid, 0.5 parts salt, 2 parts gluten powder, 0.2 parts compound enzyme preparation (composed of xylanase: cellulase: glucose oxidase = 2:1:2), and 46 parts water.

[0039] The preparation method for fruit and vegetable enzyme whole wheat bread is as follows: S1. Separate the bran component from whole wheat flour, add water to make the moisture content 50%, add xylanase and cellulase (0.12% each of xylanase and cellulase based on the dry weight of the separated bran), enzymatically hydrolyze at 50℃ for 2 hours, and then treat with moist heat at 100℃ for 15 minutes to obtain pre-enzymatically hydrolyzed bran liquid. S2. After dry mixing high-gluten wheat flour, wheat gluten, white sugar, and salt evenly, add 1 part of protein hydrolysis product, followed by compound enzyme preparation, pre-enzymatically hydrolyzed wheat bran liquid, egg liquid, fruit and vegetable enzyme liquid, and water in sequence. Mix at low speed for 3 minutes, add yeast, and mix at low speed for 1 minute. Add butter and compound emulsifier, and mix at medium speed for 12 minutes until the dough reaches the extended stage. The dough temperature is 26℃. Of the total water of 46 parts, 23 parts are fruit and vegetable enzyme liquid. The preparation method of the fruit and vegetable enzyme liquid is as follows: Fresh apples and celery are selected, rotten or spoiled parts are removed, and the vegetables are washed clean. Juices are extracted separately and then filtered. The apple juice and celery juice are mixed at a mass ratio of 4:1, and pectinase (0.05%) is added. The mixture is then enzymatically hydrolyzed at 50℃ for 2 hours. The hydrolysate is sterilized at 90℃ for 10 minutes. Activated *Lactobacillus plantarum* (2%) is inoculated into the sterilized hydrolysate, and aerobic fermentation is carried out at 32℃ for 24 hours to obtain the fruit and vegetable enzyme liquid. S3.1. Ferment the dough in the extended stage for 60 minutes at 30℃ and 80% relative humidity. After turning it over to release the air, let it rest in a shady place for 18 minutes. Then, ferment it a second time for 45 minutes at 35℃ and 85% relative humidity. S3.2. Divide the dough after the second fermentation into equal-weight dough balls, let them rest for 15 minutes, and then shape them into rounds. S3.3. Proofing: Place the dough at 38℃ and 85% relative humidity for 50 minutes, until the dough volume expands to 2.2 times its original size.

[0040] S3.4. Baking: Use a gradient heating process, first bake at 160℃ for 8 minutes, then increase the temperature to 200℃ and bake for 12 minutes.

[0041] S3.5. Cooling: Allow to cool naturally until the core temperature is ≤35℃ to obtain the finished product.

[0042] Example 2 This embodiment provides a whole wheat bread infused with fruit and vegetable enzymes, specifically comprising: 25 parts whole wheat flour, 75 parts high-gluten wheat flour, 10 parts fruit and vegetable enzymes, 1.5 parts yeast, 7 parts butter, 7 parts white sugar, 13 parts egg liquid, 0.6 parts salt, 3 parts gluten powder, 0.25 parts compound enzyme preparation (composed of xylanase:cellulase:glucose oxidase = 2.5:1.5:2.5), 48 parts water, 0.03 parts transglutaminase, and 0.3 parts compound emulsifier (composed of sodium stearoyl lactylate and glyceryl monostearate in a mass ratio of 1:1).

[0043] The preparation method for fruit and vegetable enzyme whole wheat bread is as follows: S1. Separate the bran component from whole wheat flour, add water to make the moisture content 50%, add xylanase and cellulase (0.1% each), enzymatically hydrolyze at 50℃ for 2 hours, and then treat with moist heat at 100℃ for 15 minutes to obtain pre-enzymatically hydrolyzed bran liquid. S2. After dry mixing high-gluten wheat flour, wheat gluten, white sugar, and salt evenly, add 1.5 parts of protein hydrolysis products, followed by the compound enzyme preparation, transglutaminase, pre-enzymatically hydrolyzed wheat bran liquid, egg liquid, fruit and vegetable enzyme liquid, and water in sequence. Mix at low speed for 3 minutes, add yeast, and mix at low speed for 1 minute. Add butter and compound emulsifier, and mix at medium speed for 12 minutes until the dough reaches the extended stage. The dough temperature is 27℃. Of the total water of 48 parts, 27 parts are fruit and vegetable enzyme liquid. The preparation method of the fruit and vegetable enzyme liquid is the same as in Example 1; S3.1. Ferment the dough in the extended stage at 30℃ and 80% relative humidity for 60 minutes (after the first fermentation, treat it with 40W ultrasonic assistance for 5 minutes), turn it over to degas, let it stand in the shade for 18 minutes, and then ferment it a second time at 35℃ and 85% relative humidity for 45 minutes. S3.2. Divide the dough after the second fermentation into equal-weight dough balls, let them rest for 15 minutes, and then shape them into rounds. S3.3. Proofing: Place the dough at 38℃ and 85% relative humidity for 50 minutes, until the dough volume expands to 2.2 times its original size; S3.4. Baking: Use a gradient heating process, first bake at 160℃ for 8 minutes, then increase the temperature to 200℃ and bake for 12 minutes; S3.5. Cooling: Allow to cool naturally until the core temperature is ≤35℃ to obtain the finished product.

[0044] Comparative Example 1 This comparative example provides a whole wheat bread without added fruit and vegetable enzymes. The ingredient formula is as follows: 20 parts whole wheat flour, 80 parts high-gluten wheat flour, 1.2 parts yeast, 6 parts butter, 6 parts white sugar, 12 parts egg liquid, 0.5 parts salt, 2 parts wheat gluten, 0.2 parts compound enzyme preparation, and 55 parts water (total water content is the same as in Example 1). The preparation method is exactly the same as in Example 1.

[0045] Comparative Example 2 This comparative example provides a whole wheat bread made without enzymatic pretreatment of wheat bran. The ingredient formula is the same as in Example 1. The preparation method omits the S1 wheat bran pretreatment step, directly mixing whole wheat flour with other ingredients; the remaining steps are the same as in Example 1.

[0046] Test Example 1 The breads prepared in Examples 1-2 and Comparative Examples 1-2 were subjected to sensory evaluation, textural properties, and shelf life testing. The results are as follows: Table 1 Comparison of quality indicators for each embodiment and comparative example Sensory evaluation criteria: appearance (20 points), color (15 points), internal texture (25 points), taste (30 points), and flavor (10 points). The sensory evaluation panel consisted of 10 trained food professionals, and the average score was taken.

[0047] (1) Specific volume determination: The millet exclusion method was used (the principle is the same as the rapeseed replacement method). The specific operation steps are as follows: Weigh the whole bread that has been cooled to room temperature as W g; place the bread in a transparent container of known volume, and slowly fill it with millet to the edge of the container (avoid compaction and the formation of gaps), and record the volume of millet used V1; after removing the bread, fill it with millet again to the same height, and record the volume V2; bread volume V = V2-V1 (mL); specific volume = V / W (mL / g). Each group of samples was measured in parallel 3 times, and the average value was taken.

[0048] (2) Texture property determination: Bread slices with a thickness of 2 cm were cut using a bread slicer and used as texture test samples. A TA.XT-Plus texture analyzer was used for TPA full texture analysis to obtain physical property test curves. Parameters such as hardness, elasticity, and cohesion were calculated. The texture analyzer parameters were set as follows: probe model P / 36; sensing force (trigger force) 5 g; data acquisition rate 3 mm / s; testing speed 2 mm / s; compression speed 2 mm / s; compression degree 50%; residence time between two compressions 5 s. Each sample was measured in parallel 5 times, and the average value was taken after the test.

[0049] (3) Sensory evaluation: An evaluation team of 10 professionally trained food sensory evaluators will conduct blind evaluations of the samples in a standard sensory evaluation room (temperature 22±2℃, relative humidity 50%±10%, odorless, and uniform lighting). Evaluation items and weights: appearance (20 points), color (15 points), internal texture (25 points), taste (30 points), flavor (10 points), for a total of 100 points. Samples will be provided after being randomly numbered, and the evaluators will score them independently. The average score will be used as the final sensory score.

[0050] (4) Shelf life test: The samples were placed in a constant temperature and humidity chamber and stored at a temperature of 25±2℃ and a relative humidity of 60%±5%. Microbiological index testing and limits were carried out in accordance with GB 7099-2015 "National Food Safety Standard for Pastries and Bread" (total bacterial count and coliform bacteria were tested using a three-level sampling scheme with n=5 and c=2; mold limits, etc.), with the specific limits being: total bacterial count m=10 3 CFU / g, M=10 4 CFU / g; coliform bacteria m=10 CFU / g, M=10 2 CFU / g; mold ≤10 CFU / g. Pathogenic bacteria limits comply with the relevant provisions of GB 29921. Sensory evaluation was also conducted; the test was terminated when the sample showed obvious mold, off-odor, rancidity, or a sensory score below 60 points, and the shelf life was recorded. Each group of samples was observed in triplicate, and the shortest time was taken as the shelf life.

[0051] As shown in Table 1, the whole wheat bread prepared by fruit and vegetable enzymes in Examples 1 and 2 of this invention has lower hardness and higher elasticity, larger specific volume, fine and uniform internal structure, good pore distribution, significantly extended shelf life, and overall quality superior to the comparative examples. This invention effectively solves the problems of small volume and coarse texture of whole wheat bread through the synergistic effect of wheat bran enzymatic hydrolysis pretreatment and compound enzyme preparation. Wheat bran enzymatic hydrolysis pretreatment (xylanase + cellulase enzymatic hydrolysis combined with wet heat treatment) can convert insoluble dietary fiber into soluble fiber, reduce the water-holding capacity of wheat bran, and promote the migration of water to gluten protein; while the compound enzyme preparation (xylanase, cellulase, and glucose oxidase compounded in a specific ratio) further enhances fiber degradation and strengthens the gluten network through oxidation. The two synergistically and significantly improve the gas-holding capacity and processing performance of the dough. By comparing Comparative Example 1 (without fruit and vegetable enzymes) and Comparative Example 2 (wheat bran without enzymatic hydrolysis pretreatment) with the examples, it can be seen that there is a significant synergistic effect between fruit and vegetable enzymes and wheat bran enzymatic hydrolysis pretreatment. Comparative Example 1 had a specific volume of only 3.1 mL / g, a hardness as high as 850 g, a sensory score of only 72 points, and a shelf life of only 3 days; Comparative Example 2 had a specific volume of 3.5 mL / g, a hardness of 720 g, a sensory score of 78 points, and a shelf life of 5 days. Example 1, which simultaneously underwent pretreatment with fruit and vegetable enzymes and wheat bran enzymatic hydrolysis, increased its specific volume to 4.2 mL / g, reduced its hardness to 520 g, improved its sensory score to 91 points, and extended its shelf life to 8 days; Example 2 further optimized its various indicators, reaching 4.5 mL / g, 480 g, 94 points, and 10 days, respectively. The above results indicate that using fruit and vegetable enzymes alone or performing wheat bran enzymatic hydrolysis pretreatment alone has limited effect on improving the quality of whole wheat bread. However, the synergistic effect of the two significantly improves the dough's gas retention, textural properties, and storage stability. This demonstrates that an effective synergistic mechanism is formed between the organic acids and active enzymes in the fruit and vegetable enzymes, the soluble fiber produced by wheat bran pretreatment, and the compound enzyme preparations, thereby better solving the technical problems of small volume, coarse texture, and short shelf life of whole wheat bread.

[0052] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A whole wheat bread infused with fruit and vegetable enzymes, characterized in that, By weight, it includes the following ingredients: 15-30 parts whole wheat flour, 70-85 parts high-gluten wheat flour, 5-12 parts fruit and vegetable enzyme liquid, 0.8-1.8 parts yeast, 4-8 parts butter, 4-8 parts white sugar, 8-15 parts egg liquid, 0.3-0.8 parts salt, 1-4 parts gluten powder, 0.05-0.5 parts compound enzyme preparation, and 38-52 parts water; The compound enzyme preparation includes xylanase, cellulase and glucose oxidase.

2. The whole wheat bread with fruit and vegetable enzymes according to claim 1, characterized in that, The mass ratio of the xylanase, the cellulase and the glucose oxidase is 1-3:1-2:1-3 by weight.

3. A method for preparing whole wheat bread with fruit and vegetable enzymes as described in claim 1 or 2, characterized in that, Includes the following steps: S1. Separate the bran from the whole wheat flour, add water to a moisture content of 40-60%, add a compound enzyme preparation for enzymatic hydrolysis, and then treat with moist heat at 95-105℃ for 10-20 minutes to obtain pre-enzymatically hydrolyzed bran liquid. S2. Dry mix high-gluten wheat flour, wheat gluten, white sugar and salt, add the hydrolysate of protein, then mix with compound enzyme preparation, transglutaminase, pre-enzymatic wheat bran liquid, egg liquid, fruit and vegetable enzyme liquid and water, add yeast and continue mixing, then add butter and compound emulsifier and mix until the dough reaches the extended stage. S3. After the dough in the extended stage undergoes a first fermentation, intermediate proofing, and second fermentation, it is then divided, shaped, proofed, baked, and cooled in sequence to obtain fruit and vegetable enzyme whole wheat bread.

4. The preparation method according to claim 3, characterized in that, In step S1, the moisture content of wheat bran is 45-55%, the enzymatic hydrolysis temperature is 45-55℃, and the enzymatic hydrolysis time is 1-3 hours.

5. The preparation method according to claim 3, characterized in that, In step S2, the fruit and vegetable enzyme liquid accounts for 30% to 60% of the total water content in the dough.

6. The preparation method according to claim 3, characterized in that, The conditions for primary fermentation are: temperature 28–32℃, relative humidity 70%–85%, and time 45–90 min.

7. The preparation method according to claim 3, characterized in that, The conditions for intermediate proofing include: after turning over to release air, letting it stand at 24-28°C for 15-20 minutes.

8. The preparation method according to claim 3, characterized in that, The secondary fermentation conditions are: temperature 32-38℃, relative humidity 80%-90%, and time 30-60 minutes.

9. The preparation method according to claim 3, characterized in that, The baking process can be carried out in one of the following ways: bake at 180-210℃ for the top heat and 190-220℃ for the bottom heat for 15-25 minutes; or bake at 150-170℃ for 5-10 minutes first, and then increase the temperature to 190-220℃ for 10-15 minutes.

10. The preparation method according to claim 3, characterized in that, The cooling method includes removing the baked bread and allowing it to cool naturally until the center temperature is ≤35°C.

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