Low-GI high-fiber wholewheat biscuit and preparation method thereof

Abstract

The invention belongs to the technical field of food processing, particularly relates to a low-GI high-fiber wholewheat biscuit and a preparation method thereof, and further relates to application of the low-GI high-fiber wholewheat biscuit as a low-glycemic-index food to regulation of intestinal flora. The soluble dietary fiber inulin is added into the whole wheat flour, the processing characteristics of the whole wheat flour and dough are remarkably improved through the addition of the inulin, the color and luster of the biscuit are also remarkably improved, the prepared low-GI high-fiber whole wheat biscuit has good taste and good crispness, and the content of total dietary fibers in the biscuit is as high as 19%. The GL value of the low-GI high-fiber whole-wheat biscuit is only 8.20, the GI value is 50.24, the GL value and the GI value are obviously lower than those of whole-wheat biscuits, and the low-GI high-fiber whole-wheat biscuit belongs to low-blood-sugar-load food and has a better adjusting effect on intestinal flora and short-chain fatty acid compared with the whole-wheat biscuits.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, and in particular relates to a low-GI, high-fiber whole-wheat biscuit and a preparation method thereof, and also relates to the use of the low-GI, high-fiber whole-wheat biscuit as a low-glycemic index food in regulating intestinal flora and the types and contents of short-chain fatty acids. Background Art

[0002] As a convenient instant food, biscuits have always been popular among consumers. However, traditional biscuit recipes are mostly based on refined flour, sucrose and oil, making them high-sugar and high-calorie baked foods. This leads to core technical problems such as high glycemic index, unbalanced nutritional structure, and poor palatability, which makes many people who are trying to lose weight and diabetic patients stay away from them.

[0003] Although whole-wheat biscuits made with whole-wheat flour instead of refined wheat flour have advantages such as low calories and rich nutrition, the high insoluble dietary fiber content makes the biscuits more difficult to process, and the biscuits have poor palatability, low consumer acceptance, and unsatisfactory market promotion.

[0004] Existing technologies mainly improve the dough quality and the palatability of biscuits by adding improvers to whole wheat flour. For example, patent CN103039577A discloses the use of multiple improvers such as endoxylanase, active wheat gluten and gum arabic to improve the quality of whole wheat biscuits.

[0005] However, different types of improvers have significant differences in their effects on dough quality and biscuit quality when interacting with other ingredients as raw materials. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a low GI high-fiber whole wheat biscuit and a preparation method thereof.

[0007] The low-GI high-fiber whole-wheat biscuits provided by the present invention are prepared from the following raw materials: 100 parts of whole-wheat flour, and the following auxiliary materials in the following weight fractions based on the weight of the whole-wheat flour: 15-30 parts of edible oil, 10-30 parts of maltitol, 3-10 parts of skim milk powder, 3-15 parts of soluble dietary fiber, 1-3 parts of soy lecithin, 1-3 parts of a compound leavening agent, 0.2-1 part of salt, and 20-50 parts of water. Preferably, the whole wheat flour is a mixture of bran flour and wheat flour, and the bran flour accounts for 10%-30% of the weight of the wheat flour, and the soluble dietary fiber is selected from at least one of inulin, oligofructose, resistant dextrin, and isomaltooligosaccharide.

[0008] Preferably, the soluble dietary fiber is inulin.

[0009] Preferably, the edible oil is blended from any one of peanut oil, soybean oil, olive oil, and rapeseed oil with butter, wherein the butter accounts for 30%-60% of the weight of the edible oil.

[0010] As further preferred, the edible oil is blended from peanut oil and butter, and the butter accounts for 50% of the weight of the edible oil.

[0011] Preferably, the composite leavening agent is a mixture of ammonium bicarbonate and sodium bicarbonate, and the added mass ratio of ammonium bicarbonate to sodium bicarbonate is 1:1~2.

[0012] Furthermore, the low GI high-fiber whole wheat biscuits provided by the present invention include: 100 parts of whole wheat flour, and the following auxiliary materials in the following weight fractions based on the weight of the whole wheat flour: 10 parts of peanut oil, 10 parts of butter, 20 parts of maltitol, 5 parts of skimmed milk powder, 12 parts of inulin, 1.5 parts of soy lecithin, 0.8 parts of ammonium bicarbonate, 1.2 parts of sodium bicarbonate, 0.6 parts of salt, and 25 parts of water; the whole wheat flour is a mixture of bran flour and wheat flour, and the bran flour accounts for 20% of the weight of the wheat flour.

[0013] Preferably, the total dietary fiber content in the low GI high-fiber whole wheat biscuits provided by the present invention is 11%-20%. More preferably, the total dietary fiber content in the biscuits is 19%. The total dietary fiber mentioned here includes soluble dietary fiber and insoluble dietary fiber.

[0014] The present invention also provides a method for preparing the low GI high-fiber whole-wheat biscuits, comprising the following steps: Preparation of S1 raw materials: sieve wheat flour and wheat bran powder and mix them evenly to make whole wheat flour; the wheat bran powder accounts for 10%-30% of the weight of the wheat flour, and accurately weigh other auxiliary materials at the same time; S2 Premixing of auxiliary materials: Beat the weighed auxiliary materials until they are evenly mixed and free of lumps; S3 dough mixing: after uniformly mixing the whole wheat flour in S1 and the auxiliary materials in S2, add 20-50 parts of water, put the mixture into a dough mixer and mix for 5-10 minutes, then place the mixture in a fermentation box and let it stand for 25-50 minutes to obtain mature dough for later use; S4 Rolling: Use a dough sheeter to roll the dough in S3, rotating it 90 degrees continuously during the rolling process. After multiple folding and rolling, the dough is rolled into a sheet of uniform thickness. Use a biscuit mold to press the dough into shape and place it on a plate. S5 Baking: Set the upper and lower fire temperatures and baking time of the oven, preheat it first, and then bake it in the oven. The upper fire temperature during baking is 120-180℃, the lower fire temperature is 110-140℃, and the baking time is 15-20 minutes; S6 Cooling and shaping: After baking, cool the cookies to room temperature.

[0015] In addition, the application of the above-mentioned high-fiber whole-wheat biscuits as low-glycemic index foods in regulating intestinal flora and the types and contents of short-chain fatty acids is also the focus of protection of the present invention.

[0016] The beneficial effects of the present invention are: (1) Provided is a whole-wheat biscuit with a low GI and high dietary fiber content. The GL value of the whole-wheat biscuit is 8.20 and the GI value is 50.24, which are significantly lower than those of whole-wheat biscuits (GL value is 12.77 and GI value is 68.39) and wheat biscuits (GL value is 17.44 and GI value is 81.52). It is a low glycemic load food. In addition, the total dietary fiber content in the biscuit is as high as 19%, which is a high dietary fiber content food. Compared with whole-wheat biscuits, it has better regulating effects on intestinal flora and short-chain fatty acids. (2) The present invention adds an appropriate amount of inulin to whole wheat flour. The addition of inulin significantly improves the processing characteristics and dough quality of whole wheat dough, increases the ductility and fluffiness of the dough, improves the baking characteristics of the biscuits, and the color of the biscuits is significantly improved compared with whole wheat biscuits, and is not much different from the color of wheat biscuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the RVA curve of whole wheat flour with different soluble dietary fiber content; Figure 2 The T2 relaxation time curve (A) and moisture distribution diagram (B) of whole wheat dough with different soluble dietary fibers added; Figure 3 This is a sensory rating chart for whole-wheat biscuits with different soluble dietary fibers added; Figure 4 To study the sensory effects of inulin, maltitol, blending oil and compound leavening agent addition on low GI high fiber whole wheat biscuits; Figure 5 The starch hydrolysis rate of whole wheat biscuit samples with different soluble dietary fibers added; Figure 6 This is a graph showing the pH changes of different biscuits during the fermentation process in healthy people, prediabetic people, and diabetic people; Figure 7 The changes in total acid content of different biscuits during the fermentation process among different populations; Figure 8 The changes in the content of short-chain fatty acids in different biscuits during the fermentation process among different populations; Figure 9 The PCoA analysis of the bacterial composition of fermentation liquid after fermentation of different biscuits in different populations; Figure 10 The results of the intestinal flora phylum level analysis of the fermentation liquid of different biscuits fermented in different populations; Figure 11 These are the results of intestinal flora genus level analysis of fermentation liquid from different biscuits fermented in different populations. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the present invention, the present invention will be further explained in conjunction with specific embodiments.

[0019] Example 1 Add 20% by weight of wheat bran powder to wheat flour and mix well to prepare whole wheat flour; Taking the weight of whole wheat flour as 100%, sifted inulin, resistant dextrin, isomaltooligosaccharide and fructooligosaccharide were added to the whole wheat flour at a ratio of 12% to prepare different types of high-fiber whole wheat flour.

[0020] Among them, wheat flour is recorded as WF, whole wheat flour is recorded as WFF, high-fiber whole wheat flour with added inulin is recorded as WWF-IN, high-fiber whole wheat flour with added resistant dextrin is recorded as WWF-RD, high-fiber whole wheat flour with added isomaltooligosaccharide is recorded as WWF-IMO, and high-fiber whole wheat flour with added fructooligosaccharide is recorded as WWF-FOS.

[0021] The effects of different soluble dietary fiber additions on the gelatinization properties of whole wheat flour are shown in Table 1. The gelatinization properties of various whole wheat flours measured by Rapid Visco Analyzer (RVA) are shown in the attached table. Figure 1 The effects on the thermodynamic properties of whole wheat flour are shown in Table 2, the effects on the texture of whole wheat dough are shown in Table 3, and the effects on the tensile properties of whole wheat dough are shown in Table 4.

[0022] Table 1 Effects of different soluble dietary fibers on the gelatinization properties of whole wheat flour Sample name Peak viscosity (cP) Peak-to-valley viscosity (cP) Final viscosity (cP) Disintegration value (cP) Regeneration value (cP) WF 2253.00±27.87a 1146.33±14.98a 2296.67±41.36a 1106.67±13.32a 1150.33±26.41a WWF 1549.00±26.66b 808.67±12.06b 1714.67±31.34b 740.33±15.04b 906.00±19.47b WWF-IN 1033.00±21.63c 584.00±10.15c 1271.00±21.00c 449.00±11.53c 687.00±11.14c WWF-RD 1021.33±26.63c 576.00±12.12c 1254.33±28.02c 445.33±15.50c 678.33±16.56c WWF-IMO 1029.67±11.85c 586.00±3.61c 1259.00±15.62c 443.67±9.71c 673.00±13.45c WWF-FOS 1045.00±37.32c 594.33±21.57c 1294.00±37.51c 450.67±15.89c 699.67±15.95c

[0023] Note: Different lowercase letters in the same column indicate significant differences ( p <0.05, with the same lowercase letters indicating no significant difference ( p >0.05), the following are the same and will not be repeated here.

[0024] Table 2 Effects of different soluble dietary fibers on the thermodynamic properties of whole wheat flour Sample name Initial gelatinization temperature (℃) Peak temperature (℃) Termination gelatinization temperature (℃) Gelatinization enthalpy (J / g) WF 58.79±0.12c 64.21±0.14b 70.28±0.09c 2.26±0.01a WWF 59.31±0.16b 64.89±0.92b 70.82±0.91bc 1.85±0.07b WWF-IN 60.69±0.04a 66.32±0.24a 71.54±0.05abc 1.73±0.03c WWF-RD 60.68±0.41a 66.41±0.15a 72.40±0.71b 1.65±0.02d WWF-IMO 60.85±0.11a 66.43±0.18a 72.49±0.01a 1.58±0.01d WWF-FOS 60.79±0.98a 66.52±0.28a 72.22±0.79ab 1.58±0.03d

[0025] Table 3 Effects of different soluble dietary fibers on the texture of whole wheat dough Sample name Hardness (g) Cohesion elasticity Adhesion WD 4611.40±12.51f 0.54±0.01c 0.97±0.05a 2505.57±56.60c WWD 11238.84±157.36a 0.41±0.02d 0.96±0.03a 4568.96±194.95a WWD-IN 4949.36±39.63e 0.61±0.01ab 1.06±0.11a 3002.90±80.25b WWD-RD 5255.96±42.22c 0.62±0.06a 1.06±0.09a 3239.67±314.91b WWD-IMO 5080.82±45.13d 0.61±0.06a 0.98±0.17a 3097.86±258.47b WWD-FOS 5916.84±75.89b 0.54±0.02bc 0.96±0.11a 3215.32±120.78b

[0026] Table 4 Effects of different soluble dietary fibers on the tensile properties of whole wheat dough Experimental groups Tensile strength (g) Ductility (mm) WD 42.51±0.36e 17.61±1.05a WWD 67.15±2.50a 8.55±0.70d WWD-IN 53.20±0.42d 15.99±0.95b WWD-RD 58.36±1.49c 13.25±0.75c WWD-IMO 54.28±0.38d 13.13±0.68c WWD-FOS 64.61±1.17b 12.83±0.18c

[0027] The data in Tables 1 and 2 show that the addition of soluble dietary fiber significantly reduces the gelatinization parameters of whole-wheat flour, including peak viscosity, peak-to-valley viscosity, final viscosity, disintegration value, and retrogradation value. The thermodynamic parameters, including the initial gelatinization temperature, peak temperature, and final gelatinization temperature, all increase significantly. The initial gelatinization temperature of various high-fiber whole-wheat flours ranged from 60.68°C to 60.85°C, and the final gelatinization temperature ranged from 71.54°C to 72.49°C, both significantly higher than the initial gelatinization temperature (59.31°C) and final gelatinization temperature (70.82°C) of whole-wheat flour. Compared with whole-wheat flour, the gelatinization enthalpy of high-fiber whole-wheat flours obtained by adding different soluble dietary fibers decreased. This may be because the water-binding capacity of soluble dietary fiber reduces the water utilization of starch granules, reducing the degree of gelatinization and, consequently, the gelatinization enthalpy. Among the three high-fiber whole-wheat flours, the gelatinization enthalpy of the high-fiber whole-wheat flour supplemented with inulin was significantly higher than that of the whole-wheat flours supplemented with the other three soluble dietary fibers.

[0028] Table 3 shows that the hardness and adhesiveness of high-fiber whole-wheat dough after adding different soluble dietary fibers were significantly reduced compared with whole-wheat dough, and the cohesion was significantly improved. The dough hardness was ranked from low to high as WWD-IN, WWD-IMO, WWD-RD, and WWD-FOS.

[0029] Table 4 shows that the tensile strength of high-fiber whole-wheat dough after adding dietary fiber was significantly lower than that of whole-wheat dough, and the extensibility was significantly improved. Among them, the tensile strength of WWD-IN, WWD-IMO, WWD-RD, and WWD-FOS dough decreased by 20.77%, 19.17%, 13.09%, and 3.78%, respectively. The extensibility of the dough from high to low is WWD-IN, WWD-RD, WWD-IMO, and WWD-FOS.

[0030] The above results show that compared with the other three soluble dietary fibers, the addition of inulin has the best effect on improving the tensile properties of whole wheat dough.

[0031] The water distribution in high-fiber whole-wheat dough samples with different soluble dietary fibers was measured using a nuclear magnetic resonance imaging analyzer. Figure 2 As shown, Figure 2 In the figure, (A) is the T2 relaxation time curve, and (B) is the water distribution diagram.

[0032] (A) Three peaks are clearly visible in the figure: bound water, weakly bound water, and free water, represented by T21, T22, and T23, respectively, from left to right. Compared with wheat dough, the T22 and T23 peak times of whole-wheat dough shift to the left, indicating that water molecules are more tightly bound to other molecules and the binding force on water molecules increases, indicating that the overall mobility of water molecules in free water and intermediate water in the whole-wheat dough system decreases. Compared with whole-wheat dough, the T22 and T23 peak times of high-fiber whole-wheat dough shift to the right after adding different soluble dietary fibers, indicating that the whole-wheat dough with the addition of soluble dietary fibers shows a trend of increased water molecule mobility.

[0033] (B) The figure shows that compared with wheat dough, whole wheat dough has a lower bound water content, and significantly higher weakly bound water and free water contents. Compared with whole wheat dough, high-fiber whole wheat dough with different soluble dietary fibers added has a significantly increased bound water content and a significantly decreased weakly bound water content. It can be seen that the addition of soluble dietary fiber can significantly improve the ability of whole wheat dough to bind water and make the network structure of gluten protein more stable.

[0034] Example 2 The high-fiber whole-wheat biscuits are prepared by the following method, and the specific steps are as follows: Preparation of S1 raw materials: 100% whole wheat flour, of which bran flour accounts for 20% of the weight of wheat flour; With whole wheat flour as the main ingredient, based on 100 parts by weight of the main ingredient, weigh out other auxiliary ingredients, the weight parts of the other auxiliary ingredients are respectively 20 parts of maltitol, 5 parts of skimmed milk powder, 20 parts of blending oil (10 parts of peanut oil, 10 parts of butter), 1.5 parts of soy lecithin, 2 parts of compound leavening agent (1.2 parts of sodium bicarbonate, 0.8 parts of ammonium bicarbonate), 0.6 parts of salt, and 9 parts of soluble dietary fiber (inulin, resistant dextrin, oligomaltodextrose, and oligofructose); S2 Premixing of auxiliary materials: Beat the weighed auxiliary materials until they are evenly mixed and free of lumps; S3 dough mixing: Mix the whole wheat flour in S1 and the auxiliary materials in S2 evenly, put them into a dough mixer and mix them for 5 minutes, then place them in a fermentation box and let them stand for 30 minutes; S4 Rolling: Use a dough sheeter to roll the dough in S3. The dough is rotated 90 degrees continuously during the rolling process. After multiple folding and rolling, the dough is rolled into a sheet with uniform thickness and a flat surface without bulges. Use a biscuit mold to press the dough into shape and place it on a plate. S5 Baking: Set the upper and lower fire temperatures and baking time of the oven, preheat it first, and then bake it in the oven. The upper fire temperature is 150℃, the lower fire temperature is 135℃, and the baking time is 18 minutes. S6 Cooling and shaping: After baking, cool the cookies to room temperature.

[0035] The names of the obtained wheat, whole wheat biscuits and high-fiber whole wheat biscuits are as follows: Wheat biscuits (WB), whole-wheat biscuits (WWB), high-fiber whole-wheat biscuits with added inulin (WWB-IN), high-fiber whole-wheat biscuits with added resistant dextrin (WWB-RD), high-fiber whole-wheat biscuits with added isomaltooligosaccharides (WWB-IMO), and high-fiber whole-wheat biscuits with added fructooligosaccharides (WWB-FOS).

[0036] Ten panelists (aged 18-45, 5 women, 5 men) were selected to conduct the sensory evaluation experiment, following GB / T 16291.1-2012, "General Guidelines for the Selection, Training, and Management of Sensory Analysts." Each biscuit sample was randomly coded with three digits and of the same size (40 mm × 40 mm). Six samples were presented simultaneously. The samples were placed on white paper trays. The panelists observed the biscuits under natural light, inspected for foreign matter, smelled them, and rinsed their mouths with warm water before evaluating their flavor. A sensory scoring table was designed based on the sensory requirements for biscuits in GB / T 20980-2021, "General Rules for Biscuit Quality." Detailed scoring criteria are shown in Table 5.

[0037] Table 5 Sensory evaluation table of high-fiber whole-wheat biscuits

[0038] Table 6 Effects of different soluble dietary fibers on the color parameters of whole-wheat biscuits Sample name L* a* b* ΔE WB 71.87±0.34a 15.29±0.43cd 41.56±0.25a — WWB 54.63±0.48e 16.54±0.15a 33.22±0.26d 19.19 WWB-IN 68.67±0.57b 15.36±0.15cd 36.35±0.4b 6.11 WWB-RD 63.42±0.67c 15.01±0.44d 33.52±0.90d 11.67 WWB-IMO 59.57±0.74d 16.14±0.40ab 35.45±0.52c 13.76 WWB-FOS 60.42±1.29d 15.71±0.33bc 34.70±0.57c 13.35

[0039] In the table, L* indicates color lightness, with larger values ​​indicating brighter colors; a* indicates the degree of red-green color, with larger values ​​indicating redder colors; b* indicates the degree of yellow-blue color, with larger values ​​indicating yellower colors; the reference sample for ΔE is WB.

[0040] Table 6 shows that the L* value and b* value of whole wheat biscuits are significantly lower than those of wheat biscuits, while the a* value is higher. It can be seen that compared with wheat biscuits, the color of whole wheat biscuits is darker, the yellowness value is lower, and the overall color is brown. This may be related to the dark brown color of whole wheat flour itself. In addition, whole wheat flour contains bran flour, which contains phenolic substances. Under high-temperature baking conditions, enzymatic reactions will occur, and the dark substances generated will cause the color of the biscuits to deepen.

[0041] The addition of soluble dietary fiber can increase the brightness and yellowness of whole wheat biscuits, resulting in a better baked color.

[0042] In Table 6, ΔE represents the color difference between samples. If ΔE ≤ 1, the color difference between the samples is small and the human eye cannot see obvious color difference. When ΔE is between 1 and 3, the difference between the sample colors begins to appear, and the human eye may feel a slight color difference. When ΔE ≥ 3, the larger the value, the more obvious the color difference between the samples, and the more the human eye can observe the color difference.

[0043] Table 6 shows that, with wheat biscuits as a reference, the ΔE value of whole-wheat biscuits is 19.19, indicating that there is a significant difference in color between the two. The ΔE value of high-fiber whole biscuits with different soluble dietary fibers added is significantly lower than that of whole-wheat biscuits. It can be seen that the addition of soluble dietary fiber significantly improves the color of whole-wheat biscuits. Among them, WWB-IN has the lowest ΔE value and is closest to wheat biscuits in color. Although there is still a big difference in color between it and wheat biscuits, compared with the other three soluble dietary fibers, inulin has the best effect on improving the color of whole-wheat biscuits.

[0044] Table 7 Effects of different soluble dietary fibers on the baking characteristics of high-fiber whole biscuits Sample name Stacking weight (g) Stacking thickness (cm) Surface area (cm2) Specific volume (cm3 / g) WB 57.06±1.05a 6.02±0.06a 21.95±0.38a 2.22±0.02a WWB 44.78±0.51b 3.83±0.01b 20.64±0.15d 1.72±0.03e WWB-IN 42.76±0.97cd 3.74±0.02c 22.13±0.45a 1.91±0.01b WWB-RD 41.99±0.36d 3.75±0.06c 21.31±0.12bc 1.86±0.03c WWB-IMO 41.91±0.52d 3.71±0.05c 21.21±0.17c 1.77±0.02d WWB-FOS 43.58±0.14c 3.68±0.02c 21.74±0.09ab 1.73±0.02de

[0045] Table 7 shows that compared with wheat biscuits, whole wheat biscuits with the addition of wheat bran have poor ductility and leavening ability. This may be because the addition of wheat bran powder destroys the network structure of gluten protein, resulting in a decrease in the air retention of the dough, which in turn leads to a decrease in the leavening degree of the biscuits. The decrease in leavening degree means that the gaps inside the biscuits are reduced and the hardness increases accordingly.

[0046] However, after adding soluble dietary fiber, the ductility of whole-wheat biscuits was improved and the puffing ability increased. This may be because the addition of soluble dietary fiber diluted the gluten content, hindered the crude fiber in the gluten from piercing the gluten protein, and enhanced the dough's air retention, thereby improving the ductility and puffing ability of whole-wheat biscuits. Among them, the addition of inulin had the most significant improvement on the baking characteristics of biscuits.

[0047] Table 8 Effects of different soluble dietary fibers on the texture parameters of whole-wheat biscuits Sample name Hardness (g) Cohesion chewability WB 224.61±3.46f 0.11±0.01e 6.93±0.38e WWB 1237.32±25.90a 0.30±0.02a 78.71±4.53a WWB-IN 538.84±13.81e 0.09±0.01f 11.49±1.12e WWB-RD 753.00±35.64c 0.18±0.01c 34.46±1.92c WWB-IMO 649.11±12.09d 0.14±0.01d 19.72±2.51d WWB-FOS 817.98±18.81b 0.28±0.01b 54.29±4.35b

[0048] As shown in Table 8, the hardness, cohesiveness, and chewiness of whole-wheat biscuits were significantly higher than those of wheat biscuits. The addition of different soluble dietary fibers improved the texture of the whole-wheat biscuits, while their hardness, cohesiveness, and chewiness all decreased significantly. This may be because the added soluble dietary fiber interacts with starch granules, wrapping around them and hindering the binding of glutenin and gliadin, thus reducing the formation of the gluten network structure. Compared with high-fiber whole-wheat biscuits supplemented with the other three soluble dietary fibers, high-fiber whole-wheat biscuits supplemented with inulin had the lowest hardness, closest to the hardness level of wheat biscuits.

[0049] Attachment Figure 3 Shows the effect of adding different soluble dietary fibers on the sensory scores of whole-wheat biscuits.

[0050] Figure 3 It can be seen that the sensory scores of whole-wheat biscuits with different soluble dietary fibers added are significantly improved compared with whole-wheat biscuits, among which WWB-IN has the highest sensory score of 86.5 points.

[0051] Taking into account the effects of different soluble dietary fibers on the quality of whole wheat flour and whole wheat biscuits, the present invention selects inulin as the type of soluble dietary fiber added for subsequent high-fiber whole wheat biscuit formula optimization.

[0052] Table 9 Correlation analysis of the effects of soluble dietary fiber on the quality of whole wheat flour and whole wheat biscuits project T21 T22 T23 Dough hardness Dough tensile strength Dough extensibility Biscuit hardness Biscuit volume Sensory score T21 1 T22 -0.955** 1 T23 -0.522* 0.246 1 Dough hardness -0.945** 0.948** 0.361 1 Dough tensile strength -0.777** 0.606** 0.799** 0.695** 1 Dough extensibility 0.885** -0.787** -0.634** -0.842** -0.859** 1 Biscuit hardness -0.922** 0.803** 0.705** 0.863** 0.935** -0.953** 1 Biscuit volume 0.654** -0.452 -0.849** -0.497* -0.900** 0.799** -0.832** 1 Sensory score 0.756** -0.750** -0.311 -0.850** -0.705** 0.840** -0.796** 0.564* 1

[0053] Table 9 shows that the water-binding capacity of dough significantly influences dough quality. The bound water (T21) content in dough showed a highly significant negative correlation with dough hardness and tensile strength, but a highly significant positive correlation with dough extensibility. This may be due to the hydrogen bonding between soluble dietary fiber and water molecules, which reduces the mobility of water molecules in the dough, leading to an increase in bound water content and a decrease in weakly bound water content. This enhances the dough's water-holding capacity and improves its processing quality. Dough processing properties are closely related to biscuit quality. Biscuit production requires wheat flour with good extensibility and weak gluten. Biscuit specific volume and sensory scores showed highly significant positive correlations with dough extensibility, but highly significant negative correlations with dough hardness, dough tensile strength, and biscuit hardness. Furthermore, regarding changes in dough water migration, biscuit sensory scores showed a highly significant positive correlation with T21 and a highly significant negative correlation with T22. Water distribution can be a good predictor of dough processing properties and biscuit sensory quality. Compared with whole-wheat dough and whole-wheat biscuits containing the other three types of soluble dietary fiber, high-fiber whole-wheat dough with added inulin has higher dough extensibility, lower dough hardness and tensile strength, and the quality of whole-wheat biscuits is manifested as lower hardness and higher specific volume. Ultimately, the whole-wheat biscuits with added inulin have the highest sensory score.

[0054] Example 3 Optimization of low GI high fiber whole wheat biscuit formula The added amount of maltitol was 20 parts, the added amount of compound leavening agent was 2 parts, the added amount of blending oil was 20 parts, and the added amounts of other raw materials remained unchanged according to the basic formula. The effects of different added amounts of inulin (3 parts, 6 parts, 9 parts, 12 parts, and 15 parts) on the texture and sensory scores of low GI high-fiber whole-wheat biscuits were investigated.

[0055] The added amount of inulin was 9 parts, the added amount of blending oil was 20 parts, the added amount of compound leavening agent was 2 parts, and other raw materials remained unchanged according to the basic formula. The effects of different added amounts of maltitol (10 parts, 15 parts, 20 parts, 25 parts, 30 parts) on the texture and sensory scores of low GI high fiber whole wheat biscuits were investigated.

[0056] The added amount of inulin is 9 parts, the added amount of maltitol is 20 parts, the added amount of compound leavening agent is 2 parts, and other raw materials remain unchanged according to the basic formula. The effects of different added amounts of blending oil (15 parts, 20 parts, 25 parts, 30 parts, 35 parts) on the texture and sensory scores of low GI high fiber whole wheat biscuits were investigated.

[0057] The added amount of inulin was 9 parts, the added amount of maltitol was 20 parts, the added amount of blending oil was 20 parts, and the other raw materials remained unchanged according to the basic formula. The effects of different added amounts of compound leavening agents (1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts) on the texture and sensory scores of low GI high fiber whole wheat biscuits were investigated.

[0058] The effect of inulin, maltitol, blending oil and compound leavening agent on the sensory score of low GI high fiber whole wheat biscuits is shown in the attached figure. Figure 4 The effects of various factors on biscuit texture are shown in Table 10.

[0059] Table 10 Effects of various factors on biscuit texture

[0060] Figure 4 It shows that with the increase of the addition amount of inulin, maltitol, blending oil and compound leavening agent, the sensory average score of low GI high fiber whole wheat biscuits shows a trend of first increasing and then decreasing. Among them, when the addition amount of inulin is 12%, the addition amount of maltitol is 20%, the addition amount of blending oil is 25% and the addition amount of compound leavening agent is 2%, the sensory score of low GI high fiber whole wheat biscuits is the highest.

[0061] In addition, according to the results in Table 10, a three-level orthogonal experiment was conducted with inulin addition amounts of 9%, 12%, and 15%, maltitol addition amounts of 15%, 20%, and 25%, blending oil addition amounts of 20%, 25%, and 30%, and compound leavening agent addition amounts of 1.5%, 2%, and 2.5%.

[0062] The results of the orthogonal experiment showed that the optimized biscuit formula was 20% maltitol, 20% blended oil, 2% compound leavening agent, and 12% inulin.

[0063] A verification experiment was conducted on the optimized formula (20% maltitol, 20% blended oil, 2% compound leavening agent, 12% inulin) in the orthogonal experiment. The sensory score of the biscuit was 90.6 points, and the hardness was 407.63 g. At this time, the biscuit had a complete shape, uniform thickness, uniform color, the aroma of biscuits, appropriate chewiness and hardness, and a clear internal hierarchical structure.

[0064] The quality analysis of the whole wheat biscuits is shown in Table 11.

[0065] Table 11 Quality Analysis of Whole Wheat Biscuits Sample name protein / % Fat / % Ash content / % Total dietary fiber / % Moisture / % Available carbohydrates / % Hardness / g wheat crackers 6.59 13.40 1.50 3.27 3.93 71.31 224.61±3.46 whole-wheat crackers 8.25 14.00 2.20 11.16 3.79 60.60 1237.32±25.90 Low GI high fiber whole wheat biscuits 7.74 13.20 2.00 19.00 3.64 54.42 407.63±21.62

[0066] The table shows that the moisture content of the low-GI high-fiber whole wheat biscuits is 3.64%, and the total dietary fiber content is 19%, meeting the requirements of high-dietary fiber foods. In addition, in terms of hardness, the hardness of the low-GI high-fiber whole wheat biscuits is lower than that of the whole wheat biscuits and is close to that of the wheat biscuits.

[0067] Figure 5 showed the starch hydrolysis rate of each sample. From Figure 5 it can be seen that as time increases, the rate of increase in the starch hydrolysis rate slows down. At 180 min, the starch hydrolysis rate levels from low to high are low-GI high-fiber whole wheat biscuits, whole wheat biscuits, and wheat biscuits. This may be due to the interaction between the added inulin and starch, forming a barrier around the starch and hindering the contact between starch and enzymes, resulting in a decrease in the starch hydrolysis rate. In addition, it may also be due to the increase in the viscosity of gastrointestinal contents caused by the addition of inulin, hindering the contact between digestive enzymes and reaction substrates, reducing the diffusion rate of small molecules such as glucose, and thus reducing the starch digestion rate, achieving the effect of inhibiting starch hydrolysis.

[0068] The GI value is usually used to describe the glycemic potential of foods. Foods with a low glycemic index tend to promote a relatively stable increase in blood sugar in the human body. The glycemic index measured by in vitro digestion is GI.

[0069] The results showed that the GI value of the wheat biscuits was 81.52, belonging to high glycemic index foods (GI > 70), the GI value of the whole wheat biscuits was 68.39, belonging to medium glycemic index foods (55 < GI ≤ 70), and the GI value of the high-fiber whole wheat biscuits added with inulin was 50.24, being low glycemic index foods (GI ≤ 55).

[0070] In addition, referring to the method of Lu Qiuxian et al., 30 g of biscuits were used as the unit mass of the in vitro glycemic load indicator. The results showed that the glycemic load (GL) values ​​of wheat biscuits, whole-wheat biscuits, and low-GI high-fiber whole-wheat biscuits with added inulin were 17.44, 12.77, and 8.20, respectively. That is, the prepared high-fiber whole-wheat biscuits are low-glycemic load foods.

[0071] Example 4 The effects of low GI high fiber whole wheat biscuits on the pH value of in vitro fermentation are shown in Table 12 and the attached Figure 6 As shown, Figure 6 In the figure, (A), (B), and (C) are the changes in pH during the fermentation process of healthy human group H, prediabetic human group PD, and diabetic human group D, respectively.

[0072] Table 12 Effect of high-fiber whole-wheat biscuits on in vitro fermentation pH

[0073] The above fermentation results show that during the fermentation process, the pH value of the fermentation liquid decreased rapidly in the 0-6 h period and decreased more slowly in the 6-12 h period. In addition, after 24 h of fermentation with fecal bacterial fluid from different populations, the pH of the WWB-IN group decreased the most and had the lowest pH value, indicating that WWB-IN is more conducive to lowering the pH value of the colon environment and improving intestinal health than several other low-GI, high-fiber whole-wheat biscuits.

[0074] During the in vitro fermentation process, the changes in the content of total acid and short-chain fatty acids are shown in Table 13 and the attached Figure 7-8 As shown, Figure 7 The changes of total acid content in each group during the fermentation process are shown in Figure 2. Figure 8 The changes in acetic acid (Figure (A)-Figure (C)), propionic acid (Figure (D)-Figure (F)), and butyric acid (Figure (G)-Figure (I)) during the fermentation process of each group.

[0075] Table 13 Content of short-chain fatty acids during in vitro fermentation (mmol / L)

[0076] The results in the table show that the short-chain fatty acids produced in the fermentation broth with low-GI high-fiber whole-wheat biscuits (WWB-IN) added with inulin as the carbon source are the highest, indicating that the low-GI high-fiber whole-wheat biscuits have significant advantages in promoting the production of short-chain fatty acids.

[0077] Figure 9 (A), (B), and (C) in the middle are the results of principal component analysis (PCoA) of the bacterial composition of the fermentation broth of healthy subjects, prediabetic patients, and diabetic patients after 24 hours of fermentation, respectively.

[0078] Differences in beta diversity were observed between the different groups. As shown in the figure, in the fermentation broth using fecal microflora from healthy individuals, there was some overlap between the WWB and WWB-IN groups, indicating a certain degree of similarity in the bacterial colonies between the two groups. The WWB group showed significant differences in bacterial flora from the WB and Blank groups. In the fermentation broth using fecal microflora from individuals with prediabetes, there were significant differences between the WWB-IN group and the Blank, WB, and WWB groups. In the fermentation broth using fecal microflora from individuals with diabetes, there was some overlap in the bacterial colonies between the WB, WWB, and WWB-IN groups, indicating a certain degree of similarity in the bacterial colonies between the three groups.

[0079] The results of the intestinal flora level analysis of the fermentation liquid inoculated with fecal bacteria from different groups of people at 24 hours are shown in the appendix. Figure 10 shown.

[0080] Figure 10 The results showed that in the fermentation broth fermented with healthy human fecal microflora, the proportion of Bacteroidetes and Proteobacteria in the WWB-IN group was higher than that in the WB group, and the proportion of Fusobacteria was lower than that in the WB group. The Bacteroidetes has the function of promoting the decomposition of polysaccharides to enhance the body's immunity, and is positively correlated with the production of short-chain fatty acids. Proteobacteria is also a type of beneficial bacteria. Fusobacteria are mostly conditionally pathogenic and carcinogenic bacteria, which are commonly found in patients with colorectal cancer and enteritis. In the fermentation broth fermented with fecal microflora of people with prediabetes, the proportion of Bacteroidetes in the WWB-IN group was higher than that in the WB group. In the fermentation broth fermented with fecal microflora of people with diabetes, the proportion of Proteobacteria and Bacteroidetes in the WWB-IN group was higher than that in the WB group.

[0081] The fermentation liquid of fecal bacterial liquid from different groups of people was inoculated at 24 hours to analyze the intestinal flora at the genus level. The results are shown in the attached Figure 11 As shown, the results showed that Bacteroides, Parabacteroides, Alternaria, and Rare Micrococcus have a promoting effect on the production of short-chain fatty acids; in the fermentation broth fermented with healthy human fecal microflora, the proportions of Bacteroides, Rare Micrococcus, and Alternaria in the WWB-IN group were higher than those in the WB group, while the proportions of harmful genera such as Parasartella, Fusobacterium, and Enterobacter were lower than those in the WB group; in the fermentation broth fermented with prediabetic human fecal microflora, the proportion of Rare Micrococcus in the WWB-IN group was higher than that in the WB group, while the proportions of harmful genera such as Klebsiella and Streptococcus were lower than those in the WB group; in the fermentation broth fermented with diabetic human fecal microflora, the proportion of Parabacteroides in the WWB-IN group was higher than that in the WB group, while the proportions of harmful genera such as Bilephila and Klebsiella were lower than those in the WB group.

[0082] Through the differential analysis of intestinal flora at the phylum level and genus level, it can be seen that low-GI, high-fiber whole-wheat biscuits made with inulin have a better regulatory effect on intestinal flora and intestinal short-chain fatty acids.

Claims

1. A low GI high fiber whole wheat biscuit, characterized in that: include: 100 parts of whole wheat flour, calculated on the weight of the whole wheat flour, further comprising the following auxiliary materials in the following weight fractions: 15-30 parts of edible oil, 10-30 parts of maltitol, 3-10 parts of skim milk powder, 3-15 parts of soluble dietary fiber, 1-3 parts of soy lecithin, 1-3 parts of compound leavening agent, 0.2-1 parts of salt, and 20-50 parts of water; The whole wheat flour is a mixture of bran flour and wheat flour, and the bran flour accounts for 10%-30% of the weight of the wheat flour. The soluble dietary fiber is selected from at least one of inulin, oligofructose, resistant dextrin and oligomaltodextrose.

2. A low GI high fiber whole wheat biscuit according to claim 1, characterized in that: The edible oil is prepared by blending any one of peanut oil, soybean oil, olive oil and rapeseed oil with butter, wherein the butter accounts for 30%-60% of the weight of the edible oil.

3. The low GI high fiber whole wheat biscuit according to claim 1, characterized in that: The composite leavening agent is a mixture of ammonium bicarbonate and sodium bicarbonate, and the added mass ratio of ammonium bicarbonate to sodium bicarbonate is 1:1-2.

4. The low GI high fiber whole wheat biscuit according to claim 1, characterized in that: The total dietary fiber content in the biscuits is 11%-20%.

5. A low GI high fiber whole wheat biscuit according to any one of claims 1 to 4, characterized in that: include: 100 parts of whole wheat flour, calculated based on the weight of the whole wheat flour, also includes the following auxiliary materials by weight: 10 parts of peanut oil, 10 parts of butter, 20 parts of maltitol, 5 parts of skimmed milk powder, 12 parts of inulin, 1.5 parts of soy lecithin, 0.8 parts of ammonium bicarbonate, 1.2 parts of sodium bicarbonate, 0.6 parts of salt, and 25 parts of water; the whole wheat flour is a mixture of bran flour and wheat flour, and the bran flour accounts for 20% of the weight of the wheat flour.

6. The method for preparing the low GI high-fiber whole-wheat biscuits according to claim 1, characterized in that: The following steps are involved: Preparation of S1 raw materials: sieve wheat flour and wheat bran powder and mix them evenly to make whole wheat flour; the wheat bran powder accounts for 10%-30% of the weight of the wheat flour, and accurately weigh other auxiliary materials at the same time; S2 Premixing of auxiliary materials: Beat the weighed auxiliary materials until they are evenly mixed and free of lumps; S3 dough mixing: after uniformly mixing the whole wheat flour in S1 and the auxiliary materials in S2, add 20-50 parts of water, put the mixture into a dough mixer and mix for 5-10 minutes, then place the mixture in a fermentation box and let it stand for 25-50 minutes to obtain mature dough for later use; S4 Rolling: Use a dough sheeter to roll the dough in S3, rotating it 90 degrees continuously during the rolling process. After multiple folding and rolling, the dough is rolled into a sheet of uniform thickness. Use a biscuit mold to press the dough into shape and place it on a plate. S5 Baking: Set the upper and lower fire temperatures and baking time of the oven, preheat it first, and then bake it in the oven. The upper fire temperature during baking is 120-180℃, the lower fire temperature is 110-140℃, and the baking time is 15-20 minutes; S6 Cooling and shaping: After baking, cool the cookies to room temperature.

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