A functional bran food ingredient and method of processing the same

Abstract

The present application relates to the technical field of food processing, and provides a functional bran food ingredient and a processing method thereof, steps of which comprise: (1) mixing coarse bran, fine bran and germ of wheat flour in proportion to obtain a wheat bran-germ mixture; (2) crushing the wheat bran-germ mixture; (3) mixing the crushed wheat bran-germ mixture for semi-solid enzymolysis, and deactivating the enzyme after the enzymolysis is completed; (4) performing negative pressure exhaust dehydration on the enzymolysis product through a front extended conveying section of a double-screw extruder, and finally forming granular material through extrusion organization; (5) crushing the granular material; and (6) packaging. The present application significantly improves the SDF content, SDF / TDF ratio, WEAX and FA release amount in the bran ingredient, and improves the water absorption and processing adaptability, can significantly reduce the hardness, stickiness and chewiness of steamed buns, and improve the specific volume, so that a whole-grain flour product with soft texture and excellent taste is obtained.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and more specifically, to a functional bran food ingredient and its processing method. Background Technology

[0002] Wheat bran and germ are the main byproducts of wheat milling. In my country, wheat processing produces millions of tons of wheat bran and hundreds of thousands of tons of wheat germ annually. Wheat bran is rich in dietary fiber, B vitamins, minerals, and phenolic compounds, while wheat germ contains high-quality protein, unsaturated fatty acids, vitamin E, and various bioactive substances. Both possess extremely high nutritional value and functional activity. However, due to its coarse texture, poor palatability, and low release rate of functional components, wheat bran has traditionally been used primarily as animal feed or subjected to low-value processing, resulting in low resource utilization efficiency and low economic added value. With the upgrading of residents' dietary structure and the rapid development of the functional food market, transforming wheat processing byproducts into high-value-added functional food ingredients has become an important direction for reducing losses and increasing efficiency in the grain processing industry and for the development of whole-grain foods.

[0003] In existing technologies, bran is often applied to flour product processing through extrusion puffing or direct addition. However, these methods often fail to effectively disrupt the dense cell wall structure of the bran, resulting in insufficient release of its functional active ingredients. This not only affects the taste and texture of the flour products but also limits the improvement of their nutritional value. Furthermore, traditional enzymatic hydrolysis is mostly carried out in liquid systems, which presents problems such as difficulty in enzyme recovery and low reaction efficiency, and it is also difficult to effectively integrate with subsequent flour product processing techniques.

[0004] Therefore, there is an urgent need to develop a processing method that can efficiently release the functional active ingredients in wheat bran and improve the quality of flour products, providing a new technical path for the high-value utilization of wheat processing by-products and the industrialization of whole grain foods. Summary of the Invention

[0005] In view of this, the present invention proposes a functional bran food ingredient, its processing method and application. By combining semi-solid enzymatic hydrolysis of bran with extrusion technology, the bran is first pretreated with enzyme preparations under semi-solid conditions to effectively degrade the cell wall structure and achieve efficient release of water-soluble arabinoxylan and ferulic acid. Then, the physicochemical properties are further improved by extrusion treatment to enhance the quality of the flour products.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for processing a functional bran germ food ingredient includes the following steps: (1) Mix the coarse bran, fine bran and germ of wheat after milling in a certain proportion to obtain a wheat bran-germ mixture; (2) The wheat bran mixture is pulverized; (3) Mix the crushed wheat bran mixture into a semi-solid enzymatic hydrolysate, and inactivate the enzyme after the hydrolysate is completed; (4) The enzymatic hydrolysis product is dehydrated by negative pressure exhaust through the extended conveying section at the front of the twin-screw extruder, and finally extruded and organized to form granular material. (5) The granular material is crushed; (6) Packaging.

[0007] Furthermore, in step (2), the particle size of the wheat bran mixture after ultrafine grinding is 80-150 mesh.

[0008] Further, in step (3), the specific method of the mixed semi-solid enzymatic hydrolysis is as follows: the ultra-finely pulverized wheat bran mixture is placed in a semi-solid enzymatic hydrolysis device with a material-to-water ratio of 1:1-1:2, and xylanase and / or β-glucanase and / or mesophilic amylase and / or neutral protease are added for enzymatic hydrolysis; Furthermore, the enzymatic hydrolysis is carried out in multiple stages. Specifically, the amount of xylanase added is 0.25%-1.0% of the mass of the wheat bran-germ mixture, and the amount of β-glucanase added is 0.3%-0.6% of the mass of the wheat bran-germ mixture. The hydrolysis temperature for xylanase and β-glucanase is 45-60℃, the pH value is 5.0-6.5, and the hydrolysis time is 3-6 hours. The amount of mesophilic amylase added is 0.05%-0.15% of the mass of the wheat bran-germ mixture, the hydrolysis temperature is 50-65℃, the pH value is 5.0-7.5, and the hydrolysis time is 2-3 hours. The amount of neutral protease added is 0.2%-0.4% of the mass of the wheat bran-germ mixture, the hydrolysis temperature is 50-65℃, the pH value is 6.5-8.0, and the hydrolysis time is 2-3 hours.

[0009] Further, in step (4), the moisture content of the material is adjusted to 20%-30%; the conditions for extrusion organization are: extrusion temperature 130-170°C, and material residence time in the extruder 20-60s.

[0010] Furthermore, in step (5), the particle size of the granular material after crushing is 100-120 mesh.

[0011] This invention provides a functional bran food ingredient, which is prepared by the above-described processing method.

[0012] The present invention further proposes the application of the above-mentioned functional bran food ingredients in the production of food, including but not limited to steamed buns, bread, cakes, and biscuits.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention involves ultra-fine grinding of a wheat bran mixture, followed by multi-stage semi-solid enzymatic hydrolysis using xylanase, β-glucanase, mesophilic amylase, and neutral protease. The mixture is then dehydrated and extruded using a twin-screw extruder with an extended front conveyor section under negative pressure, and finally pulverized to obtain a functional wheat bran food ingredient. This process breaks down the dense fiber structure through ultra-fine grinding, promotes the efficient conversion of insoluble dietary fiber to soluble dietary fiber through multi-stage enzymatic hydrolysis of glycosidic bonds, and fully releases bound ferulic acid and water-soluble arabinoxylan. Combined with extrusion texturing to reshape the material network structure, this significantly increases the SDF content and SDF / TDF ratio, as well as the release of WEAX and FA, and improves its water absorption and processing adaptability. When used as a 20% backfill in whole wheat steamed buns, it significantly reduces the hardness, stickiness, and chewiness of the buns, increases their specific volume, and yields a soft, high-quality whole-grain flour product. Detailed Implementation

[0015] This embodiment proposes a functional bran food ingredient and its processing method, the steps of which include: (1) Mix the coarse bran, fine bran and germ of wheat after milling in a certain proportion to obtain a wheat bran-germ mixture; (2) The wheat bran mixture was ultra-finely pulverized; (3) Mix the ultra-finely pulverized wheat bran mixture into a semi-solid enzymatic hydrolysis, and then inactivate the enzymes after the enzymatic hydrolysis is completed; (4) The enzymatic hydrolysis products are dehydrated by negative pressure exhaust through the extended conveying section at the front of the twin-screw extruder, and finally extruded and organized to form granular materials. (5) Crush the granular material; (6) Packaging.

[0016] In a preferred embodiment, in step (2), the particle size of the wheat bran mixture after ultrafine grinding is 80-150 mesh.

[0017] As a preferred embodiment, in step (3), the specific method of the mixed semi-solid enzymatic hydrolysis is as follows: the ultra-finely pulverized wheat bran mixture is placed in a semi-solid enzymatic hydrolysis device with a material-to-water ratio of 1:1-1:2, and xylanase and / or β-glucanase and / or mesophilic amylase and / or neutral protease are added for enzymatic hydrolysis. The enzymatic hydrolysis can be carried out in multiple stages. The amount of xylanase added is 0.25% - 1.0% of the mass of the wheat bran mixture, and the amount of β-glucanase added is 0.3% - 0.6% of the mass of the wheat bran mixture. Preferably, the enzymatic hydrolysis temperature is 45-60℃, the pH value is 5.0-6.5, and the time is 3-6 h. The amount of mesophilic amylase added is 0.05% - 0.15% of the mass of the wheat bran mixture, the enzymatic hydrolysis temperature is 50-65℃, the pH value is 5.0-7.5, and the time is 2-3 h. The amount of neutral protease added is 0.2% - 0.4% of the mass of the wheat bran mixture, the enzymatic hydrolysis temperature is 50-65℃, the pH value is 6.5-8.0, and the time is 2-3 h.

[0018] As a preferred embodiment, in step (4), the moisture content of the material is adjusted to 20%-30%; the conditions for extrusion organization are: extrusion temperature of 130-170°C and material residence time in the extruder of 20-60s.

[0019] In a preferred embodiment, in step (5), the particle size of the granular material after crushing is 100-120 mesh.

[0020] Comparative Example 1 Ultrafinely ground wheat bran powder.

[0021] Comparative Example 2 Twin-screw extrusion ultrafine grinding of wheat bran germ powder.

[0022] Comparative Example 3 Wheat bran germ powder was ultra-finely pulverized by twin-screw extrusion, enzymatically hydrolyzed with xylanase (0.25%) at pH 5.0 at 50℃ for 4 hours, then heated at 100℃ for 10 minutes to inactivate the enzyme, and finally dried and pulverized to 100 mesh.

[0023] Example 1 150 parts water, 100 parts ultrafine pulverized wheat bran, enzymatic hydrolysis with xylanase (0.25%), pH 5.0, 50℃ for 4 hours, enzyme inactivation by heating at 100℃ for 10 minutes, tissue processing by twin-screw extrusion, and then pulverization to 100 mesh.

[0024] Example 2 150 parts water, 100 parts ultrafine pulverized wheat bran, enzymatic hydrolysis with xylanase (0.25%) and β-glucanase (0.3%), pH 5.0, hydrolysis at 50℃ for 4 hours, enzyme inactivation by heating at 100℃ for 10 minutes, tissue processing by twin-screw extrusion, and then pulverization to 100 mesh.

[0025] Example 3 150 parts water, 100 parts ultrafine pulverized wheat bran, enzymatic hydrolysis with xylanase (0.25%) and β-glucanase (0.3%), pH 5.0, hydrolysis at 50℃ for 4 hours, enzyme inactivation at 100℃ for 10 minutes, pH adjusted to 7.0 with 1M sodium hydroxide, addition of medium-temperature amylase (0.1%), enzymatic hydrolysis at 50℃ for 3 hours, enzyme inactivation at 100℃ for 10 minutes, tissue processing by twin-screw extrusion, and pulverization to 100 mesh.

[0026] Example 4 150 parts water, 100 parts ultrafine pulverized wheat bran, enzymatic hydrolysis with xylanase (0.25%) and β-glucanase (0.3%), pH 5.0, hydrolysis at 50℃ for 4 hours, enzyme inactivation at 100℃ for 10 minutes, pH adjusted to 7.0 with 1M sodium hydroxide, addition of medium-temperature amylase (0.1%) and neutral protease (0.2%), enzymatic hydrolysis at 50℃ for 3 hours, enzyme inactivation at 100℃ for 10 minutes, tissue processing by twin-screw extrusion, and pulverization to 100 mesh.

[0027] Table 1 shows the effect of different treatment methods on the dietary fiber composition of bran. As can be seen from Table 1, compared with Comparative Example 1, the soluble dietary fiber content of the bran samples prepared by Comparative Examples 2 and 3, and Examples 1-4, all showed a certain increase. However, Example 1 showed the largest increase, followed by Example 3. This indicates that the combined treatment of ultrafine grinding, xylanase hydrolysis, and extrusion has the highest efficiency in converting insoluble dietary fiber in bran into soluble dietary fiber.

[0028] Table 1:

[0029] Table 2 shows the effects of different treatment methods on the content of water-soluble arabinoxylan (WEAX) and ferulic acid (FA) in bran. As can be seen from Table 2, compared to Comparative Example 1, the bran samples prepared by Comparative Examples 2 and 3, and Examples 1-4 all showed an increase in WEAX and FA content. Comparative Example 3 had the highest WEAX content, while Example 3 had the highest FA content. Overall, Comparative Example 3 and Examples 1-4 showed a significant increase in WEAX and FA content, indicating that enzymatic hydrolysis is a treatment method that better releases WEAX and FA from bran. The more types of enzymes used, the greater the potential for FA release (Examples 2-4), but this can damage the structure of water-soluble arabinoxylan, leading to a decrease in WEAX content.

[0030] Table 2:

[0031] Table 3:

[0032] ΔE represents the browning degree of the sample. A larger positive value of ΔE indicates a darker color and a greater degree of browning. If the L value of the product sample decreases, it indicates that the color has darkened; an increase in the a value may make the color redder; and an increase in the b value may make the color yellower. Table 3 (Effect of different treatment methods on the color difference of bran) shows that the treatment of extrusion followed by enzymatic hydrolysis (Comparative Example 3) has less impact on the color of bran compared to the treatment of enzymatic hydrolysis followed by extrusion (Examples 1-4).

[0033] Weigh 1.5 g of sample (dry basis, M0) into a centrifuge tube, add 20 mL of water and shake well. Heat in a 30 ℃ water bath for 30 min, shaking for 30 s every 5 min to keep it in suspension. After heating, centrifuge at 4000 r / min for 15 min. Pour the supernatant into a petri dish and place in a constant temperature drying oven to dry at 105 ℃ until constant weight (M1). At the same time, weigh the mass of the precipitate at the bottom of the centrifuge tube (M2). Calculate WSI and WAI according to the formula.

[0034]

[0035] Table 4:

[0036] Table 4 shows the effects of different treatment methods on the water solubility index (WSI) and water absorption index (WAI) of bran. The water solubility index (WSI) reflects the degree of degradation of macromolecules (such as starch and protein) after extrusion and / or enzymatic hydrolysis. The water absorption index (WAI) reflects the water-holding capacity of the material network and is related to the porous structure of the product and the degree of exposure of hydrophilic groups of the macromolecules after denaturation. Products with high WAI have high rehydration rates.

[0037] Furthermore, whole wheat steamed buns were made using the prepared functional bran ingredients. The modified bran was backfilled into wheat flour at a ratio of 20%, along with 1% yeast and an appropriate amount of water. The dough was kneaded until smooth, then processed 4-5 times in a sheet press, divided into 70g portions, and kneaded again. The dough was then proofed in a proofing box at 38℃ and 85% relative humidity for 50 minutes, removed, steamed for 20 minutes, turned off the heat, and left to sit for 5 minutes. After cooling to room temperature for 1 hour, the physicochemical properties were determined.

[0038] The height and diameter of a steamed bun are measured using vernier calipers. The formula for calculating the diameter-to-height ratio of a steamed bun is as follows: R=D / H In the formula: R is the diameter-to-height ratio of the steamed bun; D is the diameter of the steamed bun, cm; H is the height of the steamed bun, cm.

[0039] The volume of the steamed bun was measured using the rapeseed displacement method. A suitable beaker was selected and filled with rapeseed. Excess rapeseed was scraped off with a ruler to ensure a smooth surface. Some of the rapeseed was poured out, and the steamed bun to be measured was placed in the beaker. The container was then filled with the poured-out rapeseed, leveled, and the volume of the remaining rapeseed was measured using a graduated cylinder. The specific volume formula is as follows: λ=V / m In the formula: λ is the specific volume, mL / g; V is the volume of the steamed bun, mL; m is the mass of the steamed bun, g.

[0040] Determination of the texture of steamed buns: The steamed buns were cut into 20 mm thin slices to expose their internal structure. Test parameters: the speeds before, during, and after the test were 2, 1, and 1 mm / s, respectively, and the strain was 50%. Hardness, elasticity, cohesion, chewiness, and toughness were recorded.

[0041] The statistical results are shown in Table 5, which illustrates the effects of different bran treatments on the diameter-to-height ratio (R) and specific volume (λ) of whole wheat steamed buns. Table 5:

[0042] Table 6:

[0043] As can be seen from Table 6 (Effect of different bran treatments on the texture of whole wheat steamed buns), the whole wheat steamed buns made in Examples 3 and 4 have the lowest values ​​of hardness, stickiness and chewiness, indicating that the bran treated in Examples 3 and 4 are more suitable for making whole wheat steamed buns.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A processing method for a functional bran germ food ingredient, characterized in that... Includes the following steps: (1) Mix the coarse bran, fine bran and germ of wheat after milling in a certain proportion to obtain a wheat bran-germ mixture; (2) The wheat bran mixture is pulverized; (3) Mix the ultra-finely pulverized wheat bran mixture with semi-solid enzymatic hydrolysis, and inactivate the enzyme after the hydrolysis is completed; (4) The enzymatic hydrolysis product is dehydrated by negative pressure exhaust through the extended conveying section at the front of the twin-screw extruder, and finally extruded and organized to form granular material. (5) The granular material is crushed; (6) Packaging.

2. The processing method according to claim 1, characterized in that, In step (2), the particle size of the wheat bran mixture after pulverization is 80-150 mesh.

3. The processing method according to claim 1, characterized in that, In step (3), the specific method of the mixed semi-solid enzymatic hydrolysis is as follows: the ultra-finely pulverized wheat bran mixture is placed in a semi-solid enzymatic hydrolysis device with a material-to-water ratio of 1:1-1:2, and xylanase and / or β-glucanase and / or mesophilic amylase and / or neutral protease are added for enzymatic hydrolysis.

4. The processing method according to claim 3, characterized in that, The enzymatic hydrolysis is carried out in multiple stages. Specifically, xylanase is added at 0.25%-1.0% of the wheat bran-germ mixture by mass, and β-glucanase is added at 0.3%-0.6% of the wheat bran-germ mixture by mass. The hydrolysis temperature for xylanase and β-glucanase is 45-60℃, the pH is 5.0-6.5, and the hydrolysis time is 3-6 hours. Mesophilic amylase is added at 0.05%-0.15% of the wheat bran-germ mixture by mass, the hydrolysis temperature is 50-65℃, the pH is 5.0-7.5, and the hydrolysis time is 2-3 hours. Neutral protease is added at 0.2%-0.4% of the wheat bran-germ mixture by mass, the hydrolysis temperature is 50-65℃, the pH is 6.5-8.0, and the hydrolysis time is 2-3 hours.

5. The processing method according to claim 1, characterized in that, In step (4), the moisture content of the material is adjusted to 20%-30%; the conditions for extrusion organization are: extrusion temperature 130-170°C, and material residence time in the extruder 20-60s.

6. The processing method according to claim 1, characterized in that, In step (5), the particle size of the granular material after crushing is 100-120 mesh.

7. A functional bran germ food ingredient, characterized in that, It is prepared by the processing method according to any one of claims 1 to 5.

8. The use of the functional bran food ingredient as described in claim 7 in the preparation of food.

9. The application according to claim 8, characterized in that, The food items include, but are not limited to, steamed buns, bread, cakes, and biscuits.

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