A high-fiber puffed grain powder and its preparation method

Abstract

This invention discloses a high-fiber puffed grain powder and its preparation method, belonging to the field of food processing technology. By weight, it comprises the following raw materials: 25-35 parts whole barley flour, 20-30 parts whole oat flour, 15-25 parts whole buckwheat flour, 10-20 parts soybean residue powder, and 5-15 parts wheat bran powder. The whole buckwheat flour contains ≥0.8 mg / g of D-chiral inositol. This invention utilizes the aforementioned high-fiber puffed grain powder and its preparation method, employing a triple synergistic technology scheme of heat-resistant phytase and cellulase combined enzymatic hydrolysis, dry powder moisture adjustment, and low-temperature puffing. This achieves a significant increase in soluble dietary fiber content and a significant optimization of the SDF / IDF ratio, effectively improving mineral bioavailability. Furthermore, low-temperature puffing protects buckwheat flavonoids and D-chiral inositol, inhibits acrylamide formation, ensures product safety, and exhibits multi-target synergistic hypoglycemic effects.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a high-dietary-fiber puffed grain powder and its preparation method. Background Technology

[0002] High-fiber puffed grain powder has gained widespread attention in recent years as a meal replacement or nutritional supplement due to its combination of dietary fiber supplementation and ease of consumption. Various methods for preparing high-fiber puffed powder have been disclosed in existing technologies, such as directly mixing and extruding whole grain raw materials like brown rice flour, oat flour, millet flour, soybean flour, and wheat bran flour, or puffing a mixture of raw materials like highland barley, oats, buckwheat, and soybean residue.

[0003] However, existing technologies still have the following shortcomings: First, there is an imbalance in the ratio of soluble to insoluble dietary fiber: existing products often prioritize total dietary fiber content, neglecting the decisive impact of the SDF / IDF ratio on product functionality and sensory quality. An excessively high IDF ratio leads to a rough texture, poor reconstitution, and low consumer acceptance; while an appropriate SDF ratio helps form a viscous sol, slowing gastric emptying and glucose absorption, and enhancing satiety. Current technologies lack methods for actively controlling the SDF / IDF ratio.

[0004] Second, the treatment efficiency for anti-nutritional factors is low: Grain raw materials contain anti-nutritional factors such as phytic acid, which can combine with minerals (iron, zinc, calcium, etc.) to form insoluble complexes, reducing their bioavailability. Conventional extrusion puffing (130~150℃) only achieves a 20%~30% degradation rate for phytic acid, with limited effectiveness. Although some studies have attempted to add phytase for enzymatic hydrolysis, the matching of the hydrolysis temperature with the optimal temperature for phytase (37~45℃) is often overlooked, leading to enzyme activity loss and an actual degradation rate of less than 50%.

[0005] Third, the blood sugar lowering function is singular: existing products mostly rely on the physical barrier effect of dietary fiber to delay glucose absorption, failing to integrate multiple blood sugar lowering factors such as barley resistant starch, oat β-glucan, and buckwheat D-chiroinositol. The content of D-chiroinositol in ordinary buckwheat is extremely low (0.1~0.5mg / g), and the conventional addition amount cannot reach an effective dose.

[0006] Therefore, developing a high-fiber puffed grain powder that can simultaneously optimize dietary fiber composition, efficiently remove anti-nutritional factors, and enhance multi-target hypoglycemic function is of great practical significance. Summary of the Invention

[0007] The purpose of this invention is to provide a high-dietary-fiber puffed grain powder and its preparation method. Through a triple synergistic technology scheme of heat-resistant phytase and cellulase combined enzymatic hydrolysis, dry powder moisture adjustment, and low-temperature puffing, the soluble dietary fiber content is significantly increased and the SDF / IDF ratio is significantly optimized, effectively improving the bioavailability of minerals. Furthermore, the low-temperature puffing process protects buckwheat flavonoids and D-chiral inositol, inhibits acrylamide formation, ensures product safety, and has a multi-target synergistic hypoglycemic effect.

[0008] To achieve the above objectives, the present invention provides a high-dietary-fiber puffed grain powder and its preparation method, comprising the following raw materials by mass: 25-35 parts of whole barley flour, 20-30 parts of whole oat flour, 15-25 parts of whole buckwheat flour, 10-20 parts of soybean residue powder, and 5-15 parts of wheat bran powder, wherein the whole buckwheat flour contains ≥0.8 mg / g of D-chiral inositol.

[0009] Preferably, the whole barley flour, whole oat flour, and whole buckwheat flour are all whole grains that have been pulverized through a 60-mesh sieve. The soybean residue flour is obtained by washing, drying, and sieving soybean residue through a 60-mesh sieve. The wheat bran flour is obtained by sieving defatted wheat bran through a 60-mesh sieve. Furthermore, the whole barley flour, whole oat flour, whole buckwheat flour, soybean residue flour, and wheat bran flour are all dried to a moisture content of ≤10%.

[0010] The above-mentioned method for preparing a high-fiber puffed grain powder includes the following steps: S1. Enzymatic hydrolysis: Mix barley flour, oat flour, buckwheat flour, soybean residue powder, and wheat bran powder to obtain a mixed powder. Take 70-80% of the total mass of the mixed powder, add a compound enzyme preparation, adjust the pH, add water to adjust the moisture content, and then incubate for enzymatic hydrolysis. S2. After enzymatic hydrolysis, the enzymatic hydrolysate is obtained. The remaining mixed powder is added to the enzymatic hydrolysate for moisture adjustment. S3. Insulate the material after moisture adjustment, and then cool it to obtain the ready-to-use material. S4. Feed the spare material into a twin-screw extruder for extrusion to obtain the extruded product; S5. After hot air drying, the puffed product is pulverized to obtain puffed grain powder.

[0011] Preferably, in S1, the compound enzyme preparation consists of phytase and cellulase, with a mass ratio of phytase to cellulase of 1:2, and the amount of the compound enzyme preparation is 0.2% of the mass of the mixed powder, which is 70-80% of the total mass of the mixed powder.

[0012] Furthermore, the phytase activity was 5000 U / g, and the cellulase activity was 10000 U / g.

[0013] Preferably, in S1, citric acid is used to adjust the pH to 5-5.5, water is added to adjust the moisture content to 45-50%, the enzymatic hydrolysis temperature is 55℃, and the enzymatic hydrolysis time is 1-2 hours.

[0014] Preferably, in S2, the moisture content is adjusted to 28-32%.

[0015] Preferably, in S3, the heat preservation temperature is 55℃, the heat preservation time is 15-30min, and the temperature is cooled to 30-40℃.

[0016] Preferably, in S4, the screw speed of the twin-screw extruder is 200-300 r / min, the barrel temperature is set as follows: Zone I 60-80℃, Zone II 100-110℃, Zone III 130-145℃, Zone IV 90-105℃, the die head diameter is 2-4 mm, and the cutter speed is 800-1000 r / min.

[0017] Preferably, in step S5, the product is dried with hot air until the moisture content is ≤8%.

[0018] Therefore, the present invention, using the above-mentioned high-dietary-fiber puffed grain powder and its preparation method, has the following beneficial effects: (1) Through the synergistic effect of the combined enzymatic hydrolysis of thermostable phytase and cellulase, cellulase hydrolyzes the cellulose skeleton in the cell wall of grains, releasing soluble dietary fibers such as β-glucan and resistant starch that were originally encapsulated. At the same time, the destruction of the cell wall by cellulase makes it easier for phytase to contact phytic acid substrates, and the two enhance each other. The SDF content of Example 1 reached 13.8%, which was 62.4% higher than that of Comparative Example 1 and 43.8% higher than that of Comparative Example 2. The SDF / IDF ratio increased from 0.32 in Comparative Example 1 to 0.61. Under similar TDF conditions, the present invention significantly improved the quality of dietary fiber through process control, thereby improving the functionality and taste of the product.

[0019] (2) The phytic acid was simultaneously hydrolyzed by heat-resistant phytase and cellulase at 55°C, achieving a phytic acid degradation rate of over 80%. The phytic acid degradation rate in Example 1 was 84.3%, which was more than 4 times higher than that in Comparative Example 1 and nearly 20 percentage points higher than that in Comparative Example 2. The significant degradation of phytic acid increased the in vitro digestibility of minerals such as iron and zinc by more than 2 times, significantly improving the nutritional absorption characteristics of the whole grain flour.

[0020] (3) It exerts its hypoglycemic effect through three synergistic pathways: oat β-glucan delays glucose absorption, barley resistant starch fermentation produces short-chain fatty acids that improve insulin sensitivity, and buckwheat D-chiroinositol enhances the insulin signaling pathway. The glucose dialysis delay index of Example 1 reached 48.2%, which was 68.5% higher than that of Comparative Example 1, 50.2% higher than that of Comparative Example 2, and 64.5% higher than that of Comparative Example 4. The glucose dialysis delay index test results show that the postprandial blood glucose response of this product is more than 45% lower than that of the same amount of glucose, and it has a significant multi-target synergistic hypoglycemic advantage; (4) The low-temperature puffing process effectively avoids the thermal degradation of buckwheat flavonoids and D-chiral inositol while ensuring full starch gelatinization. The buckwheat flavonoid retention rate in Example 1 reached 86%, and the D-chiral inositol retention rate reached 96%, while the retention rates in Comparative Example 1 were only 58% and 72%, respectively. At the same time, low-temperature puffing inhibited the formation of acrylamide, and no acrylamide was detected in Examples 1-3, ensuring the food safety of the products.

[0021] (5) Through the triple synergy of compound enzymatic hydrolysis, dry powder re-addition, and low-temperature puffing, the reconstitution and taste of the product were significantly improved. The sensory score of Example 1 was 91.5 points, which was 20% higher than that of Comparative Example 1, 11% higher than that of Comparative Example 2, 14% higher than that of Comparative Example 3, and 17% higher than that of Comparative Example 4. After reconstitution, the product forms a fine suspension without roughness or burnt bitterness, has a pure aroma, and is highly acceptable to consumers.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 The results show the total dietary fiber, soluble dietary fiber, and insoluble dietary fiber content of the puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 of this invention. Figure 2 These are the test results of phytic acid content and degradation rate of the puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 of this invention; Figure 3 These are the glucose dialysis extension index test results of the puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 of this invention; Figure 4 These are the test results of the buckwheat flavonoid retention rate, D-chiral inositol retention rate, and acrylamide content of the puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 of this invention. Detailed Implementation

[0024] This invention provides a high-dietary-fiber puffed grain powder and its preparation method, comprising the following raw materials by mass: 25-35 parts of whole barley flour, 20-30 parts of whole oat flour, 15-25 parts of whole buckwheat flour, 10-20 parts of soybean residue powder, and 5-15 parts of wheat bran powder, wherein the whole buckwheat flour contains ≥0.8 mg / g of D-chiral inositol.

[0025] In this invention, the whole barley flour, whole oat flour, and whole buckwheat flour are all whole grains that have been pulverized and passed through a 60-mesh sieve. The soybean residue powder is obtained by washing, drying, and passing through a 60-mesh sieve of soybean milk residue. The wheat bran powder is obtained by passing through a 60-mesh sieve of defatted wheat bran. Furthermore, the whole barley flour, whole oat flour, whole buckwheat flour, soybean residue powder, and wheat bran powder are all dried to a moisture content of ≤10%.

[0026] The above-mentioned method for preparing a high-fiber puffed grain powder includes the following steps: S1. Enzymatic hydrolysis: Mix barley flour, oat flour, buckwheat flour, soybean residue powder, and wheat bran powder to obtain a mixed powder. Take 70-80% of the total mass of the mixed powder, add a compound enzyme preparation, adjust the pH, add water to adjust the moisture content, and then incubate for enzymatic hydrolysis. S2. After enzymatic hydrolysis, the enzymatic hydrolysate is obtained. The remaining mixed powder is added to the enzymatic hydrolysate for moisture adjustment. S3. Insulate the material after moisture adjustment, and then cool it to obtain the ready-to-use material. S4. Feed the spare material into a twin-screw extruder for extrusion to obtain the extruded product; S5. After hot air drying, the puffed product is pulverized to obtain puffed grain powder.

[0027] In this invention, in S1, the compound enzyme preparation consists of phytase and cellulase, with a mass ratio of phytase to cellulase of 1:2, and the amount of the compound enzyme preparation is 0.2% of the mass of the mixed powder, which is 70-80% of the total mass of the mixed powder.

[0028] Furthermore, the phytase activity was 5000 U / g, and the cellulase activity was 10000 U / g.

[0029] In this invention, in step S1, citric acid is used to adjust the pH to 5-5.5, water is added to adjust the moisture content to 45-50%, the enzymatic hydrolysis temperature is 55℃, and the enzymatic hydrolysis time is 1-2 hours.

[0030] In this invention, in step S2, the moisture content is adjusted to 28-32%.

[0031] In this invention, in step S3, the heat preservation temperature is 55°C, the heat preservation time is 15-30 minutes, and the temperature is cooled to 30-40°C.

[0032] In this invention, in S4, the screw speed of the twin-screw extruder is 200-300 r / min, the barrel temperature is set as follows: Zone I 60-80℃, Zone II 100-110℃, Zone III 130-145℃, Zone IV 90-105℃, the die head diameter is 2-4 mm, and the cutter speed is 800-1000 r / min.

[0033] In this invention, in step S5, hot air is used to dry the product until the moisture content is ≤8%.

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims and are all within the protection scope of the present invention.

[0035] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0036] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0037] In this invention, unless otherwise specified, all other test materials and instruments are conventional test materials in the field and can be purchased through commercial channels.

[0038] Example 1 This invention provides a high-dietary-fiber puffed grain powder, which, by weight, comprises the following ingredients: 30 parts of whole barley flour, 25 parts of whole oat flour, 20 parts of whole buckwheat flour, 15 parts of soybean residue powder, and 10 parts of wheat bran powder, totaling 100 parts. The whole buckwheat flour contains 0.9 mg / g of D-chiroinositol.

[0039] Its preparation method includes the following steps: S1. Enzymatic hydrolysis: Mix barley flour, oat flour, buckwheat flour, soybean residue powder, and wheat bran powder to obtain a mixed powder. Take 70% of the total mass of the mixed powder and add a compound enzyme preparation. Adjust the pH to 5.2 with citric acid and adjust the moisture content to 48% with water. Then, incubate at 55℃ for 1.5 hours for enzymatic hydrolysis. The compound enzyme preparation consists of phytase and cellulase, with a mass ratio of phytase to cellulase of 1:2. The phytase activity is 5000 U / g, and the cellulase activity is 10000 U / g. The amount of the compound enzyme preparation is 0.2% of the mass of the mixed powder used in S1, that is, 0.2% of the mass of the mixed powder that accounts for 70% of the total mass of the mixed powder.

[0040] S2. After enzymatic hydrolysis, the enzymatically hydrolyzed material is obtained. The remaining mixed powder is added to the enzymatically hydrolyzed material to adjust the moisture content to 30%.

[0041] S3. Keep the material with adjusted moisture at 55℃ for 20 minutes, and then cool it to 35℃ to obtain the ready-to-use material.

[0042] S4. Feed the spare material into a twin-screw extruder for extrusion to obtain the extruded product. The screw speed of the twin-screw extruder is 250 r / min, the feeding rate is 20 kg / h, the barrel temperature is set as follows: Zone I 70℃, Zone II 105℃, Zone III 140℃, Zone IV 100℃, the die diameter is 3 mm, and the cutter speed is 900 r / min.

[0043] S5. After hot air drying the puffed product to a moisture content of 7.6%, it is pulverized and passed through an 80-mesh sieve to obtain puffed grain powder.

[0044] Example 2 The only difference between this embodiment and Embodiment 1 is that, by mass parts, it includes the following raw materials: 35 parts of whole barley flour, 30 parts of whole oat flour, 15 parts of whole buckwheat flour, 12 parts of soybean residue powder, and 8 parts of wheat bran powder, totaling 100 parts. The D-chiroinositol content in the whole buckwheat flour is 0.85 mg / g.

[0045] The only difference between the preparation method and Example 1 is that the pH was adjusted to 5 in S1, while all other conditions were the same.

[0046] Example 3 The only difference between this embodiment and Embodiment 1 is that: 25 parts of whole barley flour, 30 parts of whole oat flour, 22 parts of whole buckwheat flour, 13 parts of soybean residue powder, and 10 parts of wheat bran powder, totaling 100 parts, and the D-chiroinositol content in the whole buckwheat flour is 0.92 mg / g.

[0047] The only difference between the preparation method and Example 1 is that in S1, the mass of the mixed powder used in the enzymatic hydrolysis part accounts for 72% of the total mass of the mixed powder, the enzymatic hydrolysis pH is 5.5, the water content is 50%, and all other conditions are the same.

[0048] Comparative Example 1 The only difference between this comparative example and Example 1 is that enzymatic hydrolysis is not performed in S1. During preparation, the moisture content is directly adjusted to 30%, and then puffing is carried out. High-temperature puffing is used, with 160°C in Zone III and 140°C in Zone IV (i.e., the die temperature). All other conditions are the same.

[0049] Comparative Example 2 The only difference between this comparative example and Example 1 is that only phytase was used during enzymatic hydrolysis in S1, and no cellulase was added; all other conditions were the same.

[0050] Comparative Example 3 The only difference between this comparative example and Example 1 is that all the mixed powders were enzymatically hydrolyzed during preparation. After enzymatic hydrolysis, the moisture content of the material was 48%. Then, it was dried with hot air at 60°C until the moisture content dropped to 30%. After that, it was puffed. All other conditions were the same.

[0051] Comparative Example 4 The only difference between this comparative example and Example 1 is that no enzymatic hydrolysis was performed during preparation; all other conditions were the same.

[0052] The performance of the puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 was tested: I. Total dietary fiber (TDF), soluble dietary fiber (SDF), and insoluble dietary fiber (IDF): The test method refers to GB 5009.88-2014 "National Food Safety Standard - Determination of Dietary Fiber in Food".

[0053] The puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to enzymatic hydrolysis with heat-stable α-amylase, protease, and glucosidase to remove protein and starch. After ethanol precipitation, the powders were filtered, dried, and weighed to determine the total dietary fiber. Soluble dietary fiber was determined by ethanol precipitation of the filtrate, while insoluble dietary fiber was determined directly from the residue. The test results are shown in Table 1 and 2. Figure 1 As shown.

[0054] Table 1. Test results of total dietary fiber, soluble dietary fiber, and insoluble dietary fiber.

[0055] From Table 1 and Figure 1It can be seen that the SDF content of Example 1 is 13.8%, which is significantly higher than that of Comparative Example 1 (8.5%), Comparative Example 2 (9.6%), Comparative Example 3 (12.1%), and Comparative Example 4 (8.8%). This is mainly attributed to the synergistic effect of the combined enzymatic hydrolysis of cellulase and phytase in this technical solution. Cellulase hydrolyzes the cellulose skeleton in the cell wall of grains, releasing soluble dietary fibers such as β-glucan and resistant starch that were originally wrapped in it; at the same time, the subsequent low-temperature puffing (100℃ in the mold head) avoids the thermal degradation of SDF by conventional high temperature (140℃).

[0056] Comparative Example 1 had the lowest SDF due to the lack of enzymatic hydrolysis and high-temperature puffing; Comparative Example 2, although phytase was added, lacked cellulase, and the cell wall was not fully destroyed, resulting in limited SDF release; Comparative Example 3, although using full enzymatic hydrolysis, employed hot air drying for dehydration, causing some SDF to be lost due to structural shrinkage during the drying process; Comparative Example 4, with only low-temperature puffing and no enzymatic hydrolysis, could not convert insoluble fiber into soluble fiber.

[0057] The IDF (22.7%) of Example 1 is lower than that of most comparative examples (26.2%~26.7%), which is the core advantage of the present invention: through compound enzymatic hydrolysis, a portion of insoluble dietary fiber is converted into soluble dietary fiber, thereby reducing the IDF ratio and increasing the SDF.

[0058] Example 3 had the highest IDF (27.3%) because it had a higher proportion of soybean residue powder (13 parts), while soybean residue is mainly composed of insoluble fiber and has a lower proportion of enzymatic hydrolysis (72%), resulting in a slightly lower conversion efficiency.

[0059] The IDF of Comparative Example 3 (complete enzymatic hydrolysis + hot air drying) was 23.4%, which was close to that of Example 1, indicating that enzymatic hydrolysis itself can reduce IDF. However, hot air drying caused SDF loss (12.1% in Comparative Example 3 vs. 13.8% in Example 1), indicating that the dry powder refilling method is better for protecting the SDF after transformation.

[0060] The TDF of Example 1 was not significantly different from that of the comparative examples (only 1-2 percentage points). This is because TDF is mainly determined by the fiber content of the raw materials themselves, and the enzymatic hydrolysis and puffing processes have limited effect on increasing the total TDF.

[0061] The higher TDF (40.2% and 39.8%) in Examples 2 and 3 were mainly due to the higher proportion of barley and oats in their ingredient ratios (35 parts barley + 30 parts oats, or 25 parts barley + 30 parts oats). The total dietary fiber content of these two ingredients was higher than that of buckwheat, soybean residue and wheat bran.

[0062] Key conclusion: The difference in TDF primarily stems from the raw material ratio, rather than from the process innovation of this invention. This is precisely why this invention focuses on optimizing the SDF / IDF ratio rather than simply pursuing higher TDF.

[0063] In summary, with similar TDF levels, this invention significantly increases the SDF ratio and reduces the IDF ratio through synergistic processes. This demonstrates that this invention does not simply involve piling up high-fiber raw materials, but rather improves the functionality and sensory quality of the product by controlling the quality (soluble fiber ratio) of dietary fiber through process control.

[0064] The SDF values ​​of Examples 1-3 were all significantly higher than those of all comparative examples, which fully demonstrates the synergistic effect of the "cellulase + phytase" complex enzymatic hydrolysis and low-temperature puffing, which is the core technical feature of this invention for increasing the soluble dietary fiber content.

[0065] II. Phytic acid content and degradation rate: The test method is in accordance with GB 5009.153-2016 "National Food Safety Standard - Determination of Phytic Acid in Food".

[0066] The puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 were extracted with hydrochloric acid. Phytic acid was reacted with ferric chloride-sulfosalicylic acid for color development, and the absorbance was measured at 500 nm to calculate the phytic acid content. Degradation rate = (initial phytic acid content - final phytic acid content) / initial phytic acid content × 100%. The initial phytic acid content was the measured value of the untreated mixed powder (phytic acid content of the raw material mixed powder in Example 1 was 1.15%). The test results are shown in Table 2 and... Figure 2 As shown.

[0067] Table 2. Results of Phytic Acid Content and Degradation Rate Tests

[0068] Table 2 and Figure 2 The results showed that the phytic acid degradation rate in Example 1 reached 84.3%, significantly higher than that in Comparative Example 2 (phytase only, 70.4%) and Comparative Examples 1 and 4 (no enzymatic hydrolysis, approximately 20%). The reason for this is that: The hydrolytic action of cellulase on the cell wall makes it easier for phytase to access the phytic acid substrate in the phytic acid-protein complex, thereby increasing the degradation rate by nearly 20 percentage points compared to treatment with phytase alone. Furthermore, using a heat-resistant phytase and fully enzymatically hydrolyzing at 55°C for 1.5 hours achieved highly efficient degradation, while conventional puffing (Comparative Example 1) only degraded about 20% of the phytic acid. The degradation rate of Comparative Example 3 was similar to that of Example 1, indicating that phytic acid degradation mainly occurs during the enzymatic hydrolysis stage and is not affected by the subsequent drying method.

[0069] The degradation rates of Examples 1-3 were all above 82%, demonstrating the stability and reproducibility of the present invention. The removal effect of anti-nutritional factors by compound enzymatic hydrolysis is significantly better than that of the prior art.

[0070] III. Glucose Dialysis Delay Index (GDRI) The test method is as follows: Prepare 0.5g sample + 20mL 0.1mol / L HCl (simulated gastric juice), shake at 37℃ for 1 hour, and adjust the pH to 6.8 with NaOH.

[0071] Add 2 mL of 0.5 g / L glucose solution and 5 mL of mixed enzyme solution (pancreatin + amylase), place in a dialysis bag (molecular weight cutoff 3500 Da), and incubate in 50 mL of 0.9% NaCl solution at 37°C with shaking. Measure the glucose concentration in the dialysate every 30 minutes for a total of 180 minutes.

[0072] GDRI (%) = (Glucose dialysis volume of sample group / Glucose dialysis volume of control group (no dietary fiber)) × 100%. A higher GDRI value indicates a stronger ability of dietary fiber to delay glucose absorption. Test results are shown in Table 3 and... Figure 3 As shown.

[0073] Table 3 Results of Glucose Dialysis Delay Index Test

[0074] From Table 3 and Figure 3 It can be seen that the GDRI of Example 1 was 48.2%, which was much higher than that of Comparative Example 1 (28.6%), Comparative Example 2 (32.1%), and Comparative Example 4 (29.3%), and also higher than that of Comparative Example 3 (43.2%). GDRI reflects the ability of dietary fiber to delay glucose absorption, and is positively correlated with SDF content, viscosity, and hydration capacity. The reason is as follows: The high SDF content released by the complex enzymes retains its complete molecular chain structure and viscosity characteristics under low-temperature puffing, thus forming an efficient glucose diffusion barrier. Comparative Example 1 suffered from SDF degradation and low content due to high temperature, resulting in the lowest GDRI. Comparative Example 2 lacked cellulase, leading to insufficient SDF content and viscosity. Comparative Example 3 suffered from SDF hydration capacity damage due to hot air drying, resulting in a lower GDRI than Example 1. Comparative Example 4, although using low temperature, lacked enzymatic hydrolysis, resulting in low SDF content and a GDRI similar to Comparative Example 1. Example 2 had the highest SDF content (15.0%), but its GDRI was slightly lower than Example 1, possibly related to the slightly higher temperature in puffing zone III (145℃ vs 140℃), leading to a slight decrease in β-glucan viscosity, but the overall trend was consistent. The synergistic strategy of enzyme release and low-temperature protection in this invention significantly enhances the in vitro glycemic function of puffed grain powder.

[0075] IV. Test method for flavonoid retention rate in tartary buckwheat: The HPLC method for flavonoids in GB / T 22251-2008 "Determination of Puerarin in Health Foods" was used to quantify rutin.

[0076] The puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 were extracted ultrasonically with methanol-water (80:20), filtered through a 0.45 μm filter membrane, and injected into an HPLC system. The chromatographic column was C18 (250 mm × 4.6 mm, 5 μm), the mobile phase was methanol:0.4% phosphoric acid (45:55), the detection wavelength was 360 nm, and the flow rate was 1.0 mL / min.

[0077] Retention rate = (Rutin content in the puffed sample / Rutin content in the unpuffed buckwheat flour × Proportion of buckwheat flour added to the raw material) × 100%. The test results are shown in Table 4 and... Figure 4 As shown.

[0078] V. D-chiral inositol retention rate: The puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 were extracted with water, purified by SPE column chromatography, and analyzed by HPLC-MS. The chromatographic column was an amino column (250 mm × 4.6 mm, 5 μm), the mobile phase was acetonitrile:water (75:25), and the mass spectrometry was performed in negative ion mode. The retention rate was calculated using the same method as for flavonoids, and the test results are shown in Table 4. Figure 4 As shown.

[0079] VI. Acrylamide content: The test method is in accordance with GB 5009.204-2014 "National Food Safety Standard - Determination of Acrylamide in Food".

[0080] The puffed grain powders prepared in Examples 1-3 and Comparative Examples 1-4 were extracted with water, purified by solid-phase extraction, derivatized by bromination, and then analyzed by GC-MS using the external standard method. The detection limit was 10 μg / kg. The test results are shown in Table 4. Figure 4 As shown.

[0081] Table 4. Test results of flavonoid retention rate, D-chiroinositol retention rate, and acrylamide content in tartary buckwheat.

[0082] Table 4 and Figure 4 Data shows that the flavonoid retention rate of buckwheat in Example 1 reached 86%, the D-chiral inositol retention rate reached 96%, and acrylamide was not detected; while in Comparative Example 1, the flavonoid retention rate was only 58% and the DCI retention rate was 72% under high-temperature puffing, and acrylamide was detected at 32 μg / kg. The reason is as follows: Low-temperature puffing (100°C at the die head) effectively prevents the oxidative degradation of heat-sensitive active ingredients (flavonoids, DCI) while ensuring full gelatinization of starch and inhibiting the formation of acrylamide. The flavonoid retention rate of Comparative Example 3 (hot air drying) (79%) was lower than that of Example 1 (86%), indicating that the dry powder re-addition method avoids aerobic thermal oxidation during the drying process, further protecting the flavonoids. The retention rates of Comparative Examples 2 and 4 were similar to those of Example 1, proving that the enzymatic hydrolysis itself does not destroy these active ingredients. Therefore, the low-temperature puffing and dry powder re-addition combination process of this invention not only achieves high dietary fiber modification but also maximizes the retention of functional active ingredients in buckwheat while ensuring product safety.

[0083] VII. Sensory Evaluation: The testing method used the 9-point pleasure scale.

[0084] Ten trained food professionals (5 men and 5 women, aged 22-40) were selected. 20g of sample was weighed, mixed with 150mL of 85℃ hot water, stirred thoroughly, and evaluated immediately.

[0085] The evaluation criteria included: color (10 points), aroma (20 points), ease of mixing (20 points), smoothness of texture (30 points), sweetness and off-flavors (20 points), for a total score of 100 points. The average score from 10 people was taken, and the test results are shown in Table 5.

[0086] Table 5 Sensory rating results

[0087] As shown in Table 5, the sensory score of Example 1 was as high as 91.5, significantly higher than that of Comparative Example 1 (76.3), Comparative Example 2 (82.5), Comparative Example 3 (80.0), and Comparative Example 4 (78.5). The reason is as follows: First, the compound enzymatic hydrolysis increases the SDF content, resulting in a smooth and delicate texture after reconstitution, avoiding the roughness caused by high IDF. Second, low-temperature puffing eliminates the high-temperature burnt taste (acrylamide) and retains the natural aroma of the grains. Third, the dry powder re-addition method avoids surface crusting and off-flavors caused by hot air drying. Comparative Example 1 had the lowest score due to a burnt taste and low SDF caused by high-temperature puffing; Comparative Example 2 had no burnt taste but a rough texture due to low SDF; Comparative Example 3 had a slight burnt taste and poor reconstitution properties due to hot air drying; Comparative Example 4 had no burnt taste but a rough texture due to low SDF. Example 1 had a moderate SDF (13.8%), ensuring a delicate texture without being too viscous. Combined with the advantages of low-temperature puffing and dry powder re-addition, it achieved the highest consumer acceptance. This further demonstrates the breakthrough of the overall synergistic solution of this invention in improving the sensory quality of high dietary fiber products.

[0088] Therefore, this invention employs the aforementioned high-dietary-fiber puffed grain powder and its preparation method. Through a triple synergistic technology scheme of heat-resistant phytase and cellulase combined enzymatic hydrolysis, dry powder moisture adjustment, and low-temperature puffing, it achieves a significant increase in soluble dietary fiber content and a significant optimization of the SDF / IDF ratio, effectively improving mineral bioavailability. Furthermore, the low-temperature puffing process protects buckwheat flavonoids and D-chiral inositol, inhibits acrylamide formation, ensures product safety, and has a multi-target synergistic hypoglycemic effect.

[0089] 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 them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-fiber puffed grain powder, characterized in that: By weight, it includes the following ingredients: 25-35 parts highland barley flour, 20-30 parts oat flour, 15-25 parts tartary buckwheat flour, 10-20 parts soybean residue powder, and 5-15 parts wheat bran powder. The tartary buckwheat flour contains ≥0.8 mg / g of D-chiroinositol.

2. The high-dietary-fiber puffed grain powder according to claim 1, characterized in that: Barley flour, oat flour, and buckwheat flour are all whole grains that have been ground through a 60-mesh sieve. Soybean residue flour is obtained by washing, drying, and passing through a 60-mesh sieve from soybean milk residue. Wheat bran flour is obtained by passing defatted wheat bran through a 60-mesh sieve. All barley flour, oat flour, buckwheat flour, soybean residue flour, and wheat bran flour are dried to a moisture content of ≤10%.

3. The method for preparing a high-dietary-fiber puffed grain powder as described in any one of claims 1-2, characterized in that: Includes the following steps: S1. Enzymatic hydrolysis: Mix barley flour, oat flour, buckwheat flour, soybean residue powder, and wheat bran powder to obtain a mixed powder. Take 70-80% of the total mass of the mixed powder, add a compound enzyme preparation, adjust the pH, add water to adjust the moisture content, and then incubate for enzymatic hydrolysis. S2. After enzymatic hydrolysis, the enzymatic hydrolysate is obtained. The remaining mixed powder is added to the enzymatic hydrolysate for moisture adjustment. S3. Insulate the material after moisture adjustment, and then cool it to obtain the ready-to-use material. S4. Feed the spare material into a twin-screw extruder for extrusion to obtain the extruded product; S5. After hot air drying, the puffed product is pulverized to obtain puffed grain powder.

4. The method for preparing a high-dietary-fiber puffed grain powder according to claim 3, characterized in that: In S1, the compound enzyme preparation consists of phytase and cellulase, with a mass ratio of phytase to cellulase of 1:

2. The amount of the compound enzyme preparation is 0.2% of the mass of the mixed powder, which is 70-80% of the total mass of the mixed powder.

5. The method for preparing a high-dietary-fiber puffed grain powder according to claim 3, characterized in that: In S1, citric acid is used to adjust the pH to 5-5.5, water is added to adjust the moisture content to 45-50%, the enzymatic hydrolysis temperature is 55℃, and the enzymatic hydrolysis time is 1-2 hours.

6. The method for preparing a high-dietary-fiber puffed grain powder according to claim 3, characterized in that: In S2, the moisture content is adjusted to 28-32%.

7. The method for preparing a high-dietary-fiber puffed grain powder according to claim 3, characterized in that: In S3, the holding temperature is 55℃, the holding time is 15-30 minutes, and then it is cooled to 30-40℃.

8. The method for preparing a high-dietary-fiber puffed grain powder according to claim 3, characterized in that: In S4, the screw speed of the twin-screw extruder is 200-300 r / min, the barrel temperature is set as follows: Zone I 60-80℃, Zone II 100-110℃, Zone III 130-145℃, Zone IV 90-105℃, the die head diameter is 2-4 mm, and the cutter speed is 800-1000 r / min.

9. The method for preparing a high-dietary-fiber puffed grain powder according to claim 3, characterized in that: In S5, hot air drying is performed until the moisture content is ≤8%.

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