Low-glycemic-index steamed bun premixed flour and steamed bun product making method

Abstract

The invention belongs to the field of functional food, and discloses steamed bun premixed flour with a low glycemic index and a steamed bun product making method, and the premixed flour is composed of whole wheat flour, resistant starch (RS2 type), ultramicro highland barley flour (beta-glucan is greater than or equal to 5%), bean flour (chickpeas and Chinese yams), momordica grosvenori concentrated juice, mulberry leaf high-fiber powder, compound lactic acid bacteria powder and the like. The preparation method comprises the processes of dry-mixing premixed flour, staged temperature-controlled fermentation (35-38 DEG C to 28-30 DEG C), gradient cooling steaming (2-3 DEG C / min to 1 DEG C / min) and the like. Through the high-temperature gelatinization characteristic (85-95 DEG C) of the RS2 type resistant starch and the synergistic effect of the highland barley flour and the mulberry leaf fibers, the starch hydrolysis index is remarkably reduced to be smaller than or equal to 40%, and the eGI value is smaller than or equal to 55. The dietary fibers of the product are not less than 7g / 100g, the proteins are not less than 12g / 100g, the texture hardness is not more than 550N, and the elasticity is not less than 2.5 mm. Clinical experiments show that the postprandial blood sugar peak value of diabetic patients is reduced by 28%, and the composition is suitable for diet management of diabetic and obesity patients. The food has low GI, high nutrition and palatability, and solves the technical problems of fast sugar rise and insufficient fibers of traditional staple food.

Description

Technical Field

[0001] The invention belongs to the field of functional foods, and specifically discloses a steamed bread premix powder with a low glycemic index and a method for making a steamed bread product. Background Art

[0002] As a traditional staple food in my country, steamed bread is very popular among the public. The steamed bread commonly seen on the market is mainly made of refined wheat flour as the main raw material. In the production process of traditional steamed bread, usually only simple raw materials such as wheat flour, water, yeast, etc. are used, and it is made through conventional steps such as dough mixing, fermentation, and steaming.

[0003] Disadvantages of existing technology

[0004] High glycemic index: Refined wheat flour is quickly digested and absorbed in the human body, which leads to a rapid rise in blood sugar after eating traditional steamed bread, and a high glycemic index (GI). For diabetic patients, it is difficult to effectively control blood sugar levels, which is not conducive to the stability and treatment of the disease. Long-term excessive fluctuations in blood sugar can also cause a series of complications, posing a serious threat to the patient's health.

[0005] Single nutritional composition: Traditional steamed bread mainly provides carbohydrates, lacking other important nutrients such as dietary fiber, high-quality protein, vitamins and minerals. Dietary fiber helps promote intestinal peristalsis, reduce cholesterol absorption, and plays an important role in maintaining intestinal health and preventing cardiovascular diseases. However, the dietary fiber content in traditional steamed bread is extremely low and cannot meet the human body's needs for dietary fiber. In addition, the protein content is relatively low, and the amino acid composition is not reasonable, which cannot provide all the essential amino acids needed by the human body.

[0006] Insufficient health care function: As people's health awareness increases, higher requirements are placed on the health care function of food. Traditional steamed bread lacks ingredients with specific health care functions and cannot meet consumers' needs in preventing diseases and improving health conditions. For example, for obese patients, it is necessary to control calorie intake and increase satiety; for hypertensive patients, it is necessary to control sodium intake and supplement nutrients that help regulate blood pressure. Traditional steamed bread has obvious deficiencies in these aspects. Summary of the invention

[0007] In response to the above problems, the present invention proposes a method for making a steamed bread premix with a low glycemic index and a steamed bread product. By rationally selecting raw materials and optimizing the preparation process, the present invention aims to provide a steamed bread product suitable for dietary management of special groups such as patients with diabetes, obesity, and hypertension, and to solve the problems existing in the prior art.

[0008] The purpose of the present invention is achieved through the following technical solutions.

[0009] A low glycemic index steamed bread premix powder, comprising the following raw materials in parts by weight:

[0010] 30-40 parts of whole wheat flour, 25-35 parts of drinking water, 8-12 parts of raw soy milk, 6-8 parts of gluten, 4-6 parts of resistant starch, 3-5 parts of vegetable oil, 2-4 parts of highland barley flour, 1-2 parts of chickpea flour, 1-2 parts of yam powder, 0.5-1 parts of quinoa flour, 0.5-1 parts of oat bran powder, 0.5-1 parts of oligofructose, 0.5-0.8 parts of yeast, 0.2-0.5 parts of monk fruit concentrated juice, 0.2-0.5 parts of mulberry leaf high fiber powder, and 0.05-0.15 parts of lactic acid bacteria powder.

[0011] Furthermore, in the above-mentioned low glycemic index steamed bread premix powder, the resistant starch is high-amylose corn resistant starch RS2 type, and the gelatinization temperature range is controlled at 85-95°C.

[0012] Furthermore, in the above-mentioned low glycemic index steamed bread premix, the highland barley flour is whole highland barley flour with a β-glucan content of ≥5% after ultrafine grinding.

[0013] Furthermore, in the above-mentioned low glycemic index steamed bread premix powder, the compound lactic acid bacteria powder for food processing contains active bacteria of Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus casei, and the total number of viable bacteria is ≥

[0014] 1×10^10CFU / g.

[0015] The present invention discloses a method for preparing steamed bread with a low glycemic index from the premixed powder, comprising the following steps:

[0016] (1) Preparation of premixed powder: dry-mix whole wheat flour, gluten powder, resistant starch, highland barley flour, chickpea flour, Chinese yam powder, quinoa powder, oat bran powder, and mulberry leaf high-fiber powder;

[0017] (2) kneading: adding drinking water, raw soybean milk, non-GMO soybean oil, oligofructose, and monk fruit concentrated juice to the mixture of step (1), and kneading at 25-30° C. until dough is formed;

[0018] (3) Fermentation: Add yeast and lactic acid bacteria powder, first ferment at 35-38°C for 40-50 minutes, then transfer to 28-30°C for 20-30 minutes;

[0019] (4) Shaping and steaming: After the fermented dough is shaped, it is steamed in 100-105°C steam for 10-15 minutes.

[0020] Furthermore, in the above method, during the fermentation process of step (3), the pH value of the dough is controlled to be maintained in the range of 5-6.

[0021] Furthermore, in the above method, after steaming in step (4), a gradient cooling process is adopted: first cooling to 60°C at a rate of 2-3°C / min, and then cooling to room temperature at a rate of 1°C / min.

[0022] The invention discloses a steamed bread product with a low glycemic index, which is prepared by the method and has the following characteristics: the starch hydrolysis index in an in vitro simulated digestion test is ≤40%, and the estimated glycemic index eGI measured by a human body experiment is ≤55.

[0023] Furthermore, the above steamed bread product has a dietary fiber content ≥7g / 100g and a protein content ≥12g / 100g.

[0024] Furthermore, the present invention discloses the use of the above-mentioned premixed powder or steamed bread product in the preparation of diabetic supplementary food, characterized in that the food is suitable for the dietary management of patients with diabetes, obesity and hypertension.

[0025] Compared with the existing technology, the present invention has the following advantages and beneficial effects:

[0026] 1. Significantly reduce the glycemic index (GI):

[0027] Through the synergistic effect of RS2 resistant starch (gelatinization temperature 85-95°C) and ultrafine highland barley powder (β-glucan ≥5%), the starch enzymatic hydrolysis efficiency is inhibited, so that the in vitro starch hydrolysis index is ≤40%, and the eGI value is ≤55 (ordinary steamed bread eGI=85), meeting the international low GI food standard (GI≤55).

[0028] The concentrated monk fruit juice (sweet glycoside V ≥ 25%) replaced sucrose, inhibited the activity of α-glucosidase, and reduced glucose absorption. When it was absent, the eGI value increased by 5 units (Example 1 vs. Comparative Example 6).

[0029] 2. Nutritional enhancement and functional synergy:

[0030] Dietary fiber ≥7g / 100g: Ultrafine barley powder (3 portions) and mulberry leaf high-fiber powder (0.2-0.5 portions) contribute water-soluble fiber (β-glucan) and water-insoluble fiber (mulberry leaf polysaccharide), delaying gastric emptying and promoting intestinal health.

[0031] Protein ≥12g / 100g: Gluten powder (75% protein) and bean powder (chickpea, yam) provide high-quality plant protein to meet the high protein needs of diabetic patients and reduce muscle loss.

[0032] 3. Process innovation improves texture and shelf life:

[0033] The phased fermentation process (first 37°C then 29°C) combined with compound lactic acid bacteria (live bacteria ≥1×10^10 CFU / g) can accurately control the pH value of the dough to 5-6 and inhibit the reproduction of miscellaneous bacteria.

[0034] The gradient cooling process (2-3℃ / min→1℃ / min) inhibits starch retrogradation, making the hardness of the steamed buns ≤550N and the elasticity ≥2.5mm, which is close to the soft taste of traditional steamed buns (hardness 890N in comparison example 3).

[0035] 4. Clinical validation and applicability:

[0036] After 50 patients with type 2 diabetes consumed the product, the area under the blood glucose curve (AUC) 2 hours after the meal decreased by 32% (p<0.01), the peak blood glucose fluctuation decreased by 28%, the sensory score reached 8.5 points (out of 10 points), and the patient compliance was high.

[0037] It is suitable for replacing daily staple food for people with diabetes, obesity and hypertension. It can be produced on a large scale and the cost is 20% lower than similar low GI products.

[0038] 5. Irreplaceability of ingredients and processes:

[0039] When monk fruit concentrated juice or mulberry leaf high-fiber powder was missing, the eGI value increased to 58-66, close to the high GI threshold (70), proving that the two are essential components;

[0040] Replacing resistant starch with ordinary starch (Comparative Example 2) or canceling gradient cooling (Comparative Example 3) both resulted in texture deterioration, verifying the key role of process innovation in product performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Comparative diagram of starch hydrolysis index of steamed bread products;

[0042] Figure 2 Schematic diagram of comparison of in vitro eGI values ​​of steamed bread products;

[0043] Figure 3 Schematic diagram of comparison of dietary fiber content (g / 100g) of steamed bread products;

[0044] Figure 4 Schematic diagram of the comparison of protein content (g / 100g) of steamed bread products;

[0045] Figure 5 Comparison of hardness (N) of steamed bread products;

[0046] Figure 6 Comparison of elasticity (mm) of steamed bread products. DETAILED DESCRIPTION

[0047] To make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention. All raw materials in the embodiments of the present invention can be obtained through commercial channels.

[0048] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0049] Table 1 Raw materials

[0050]

[0051] Table 2 Equipment table

[0052]

[0053] Example 1

[0054] Basic formula and process verification

[0055] Formula (parts by weight):

[0056] 35 parts of whole wheat flour, 30 parts of water, 10 parts of raw soy milk, 7 parts of gluten, 5 parts of high-amylose corn RS2 resistant starch (gelatinization temperature 90°C), 4 parts of soybean oil, 3 parts of superfine highland barley flour with β-glucan ≥5%, 1.5 parts of chickpea flour, 1.5 parts of Chinese yam powder, 0.8 parts of quinoa flour, 0.8 parts of oat bran powder, 0.8 parts of oligofructose, 0.6 parts of yeast, 0.3 parts of monk fruit concentrated juice, 0.3 parts of mulberry leaf high-fiber powder, 0.1 parts of compound lactic acid bacteria powder (containing Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus casei, with a live bacteria count of 1.2×10^10 CFU / g).

[0057] Preparation method:

[0058] 1. After premixed powder is dry mixed, knead the dough at 28℃ for 15 minutes;

[0059] 2. Fermentation in stages (37°C / 45 minutes → 29°C / 25 minutes, pH 5.2);

[0060] 3. Steam at 105℃ for 10 minutes, and then cool down gradually (2.5℃ / min→1℃ / min).

[0061] Example 2

[0062] Comparison of Resistant Starch Types (RS3 Type)

[0063] Formula adjustment: Resistant starch was replaced with corn resistant starch RS3 (gelatinization temperature 75°C), and the rest was the same as Example 1.

[0064] Objective: To verify the inhibitory effect of RS2-type high temperature gelatinization on starch hydrolysis.

[0065] Example 3

[0066] Lactic acid bacteria combination optimization

[0067] Formula adjustment: the lactic acid bacteria powder only contains Lactobacillus plantarum (viable bacteria count 1×10^10 CFU / g), and the rest is the same as Example 1.

[0068] Objective: To verify the effect of composite bacteria on pH regulation and flavor.

[0069] Example 4

[0070] Gradient cooling parameter adjustment

[0071] Process adjustment: After steaming, the cooling rate is changed to 3℃ / min→60℃, and then 0.5℃ / min→room temperature. Purpose: To verify the control effect of the cooling rate on starch retrogradation in claim 7.

[0072] Example 5

[0073] Ultrafine highland barley powder substitution verification

[0074] Formula adjustment: highland barley flour was replaced with common highland barley flour (β-glucan 3%), and the rest was the same as in Example 1.

[0075] Purpose: To support the contribution of β-glucan content to dietary fiber in claim 3.

[0076] Example 6

[0077] No monk fruit juice concentrate recipe

[0078] Recipe adjustment: Remove monk fruit juice concentrate and increase oligofructose to 1.2 parts.

[0079] Objective: To verify the synergistic effect of natural sweeteners on GI value.

[0080] Comparative Example 1

[0081] Regular steamed bread recipe

[0082] Recipe: 70 parts of ordinary wheat flour, 40 parts of water, 5 parts of white sugar, and 1 part of yeast.

[0083] Process: Direct fermentation for 1 hour and steaming for 10 minutes.

[0084] Comparative Example 2

[0085] No Resistant Starch Formula

[0086] Recipe: Resistant starch was replaced with an equal amount of common corn starch, and the rest was the same as in Example 1.

[0087] Comparative Example 3

[0088] No gradient cooling process

[0089] Process adjustment: directly cool to room temperature after steaming, and the rest is the same as in Example 1.

[0090] Objective: To verify the effect of cooling process on texture.

[0091] Comparative Example 4

[0092] Single lactic acid bacteria fermentation

[0093] Formula adjustment: the lactic acid bacteria powder only contains Lactobacillus casei (viable bacteria count 0.8×10^10 CFU / g), and the rest is the same as Example 1.

[0094] Objective: To compare the fermentation effects of composite bacteria and single bacteria.

[0095] Comparative Example 5

[0096] Uncontrolled pH fermentation

[0097] Process adjustment: pH value was not monitored during the fermentation process, and the rest was the same as in Example 1.

[0098] Purpose: To verify the effect of pH control on product stability

[0099] Comparative Example 6

[0100] Does not contain monk fruit juice concentrate

[0101] Recipe Adjustment:

[0102] Remove monk fruit juice concentrate (0 servings)

[0103] The amount of oligofructose was increased to 1.3 parts (0.8 parts in the original formula), and the remaining ingredients were the same as those in Example 1.

[0104] Objective: To verify the independent effect of natural sweetener (monk fruit concentrated juice) on blood glucose regulation and its synergistic effect with oligofructose.

[0105] Comparative Example 7

[0106] Does not contain mulberry leaf high fiber powder

[0107] Recipe Adjustment:

[0108] Remove mulberry leaf high fiber powder (0 servings)

[0109] The amount of oat bran powder was increased to 1.5 parts (0.8 parts in the original formula), and the remaining ingredients were the same as those in Example 1.

[0110] Objective: To compare the functional differences between mulberry leaf high-fiber powder and other dietary fiber sources.

[0111] Comparative Example 8

[0112] It also does not contain monk fruit concentrated juice and mulberry leaf high-fiber powder.

[0113] Recipe Adjustment:

[0114] Remove monk fruit juice concentrate (0 servings) and mulberry leaf high-fiber powder (0 servings)

[0115] The oligofructose was increased to 1.5 parts, the oat bran powder was increased to 1.8 parts, and the other ingredients were the same as those in Example 1.

[0116] Purpose: To verify the combined effect of the lack of both on product taste, dietary fiber content and GI value Test Example 1

[0117] Test Method

[0118] Standard basis: ISO 26642:2010 "Determination of starch hydrolysis index in foods - In vitro digestion method".

[0119] Instruments and equipment: in vitro digestion simulation system (TNO TIM-1), constant temperature water bath shaker, centrifuge, glucose oxidase kit (GOD-POD method).

[0120] Experimental steps:

[0121] Sample treatment: Take 1.0 g of steamed bread sample (dried and crushed and passed through a 60-mesh sieve), add 20 mL of simulated saliva (containing 1500 U / mL of α-amylase), and shake at 37°C for 10 minutes;

[0122] Gastric digestion stage: adjust pH to 2.0, add pepsin (3000 U / mL), shake at 37°C for 2 h;

[0123] Intestinal digestion stage: adjust the pH to 6.8, add pancreatic enzyme (containing 2000U / mL amylase and 50U / mL glucosidase), and shake at 37°C for 2 hours;

[0124] Termination of the reaction: remove the liquid and place in a boiling water bath for 10 minutes to inactivate the enzyme, centrifuge (5000 rpm, 10 minutes) and collect the supernatant;

[0125] Glucose determination: GOD-POD method was used to determine the glucose content and calculate the starch hydrolysis rate.

[0126] Calculation formula:

[0127] Starch hydrolysis index (%) = (glucose released by the sample / total available starch) × 100%;

[0128] (Total available starch was determined by referring to Megazyme Resistant Starch Assay Kit (K-RSTAR))

[0129] eGI value (estimated glycemic index) = 39.71 + 0.549 × starch hydrolysis index (literature model: Goni et al., 1997).

[0130] Data Analysis:

[0131] Each group was repeated three times, and the results were expressed as mean ± standard deviation;

[0132] One-way analysis of variance (ANOVA) was used to compare the differences among the groups, with a significance level of p<0.05.

[0133] The results are shown in Table 3 and Figure 1 and Figure 2 shown.

[0134] Table 3 In vitro starch hydrolysis and eGI values

[0135]

[0136]

[0137] From the data in Table 3, we can see that:

[0138] Example 1 vs. Comparative Example 1: The starch hydrolysis index decreased by 34% (72%→38%), and the eGI value decreased from 85 to 53, indicating that resistant starch (RS2 type) and the gradient cooling process significantly inhibited starch enzymatic hydrolysis (p<0.01).

[0139] Example 1 vs. Example 2: The eGI value of RS3 resistant starch increased by 9 units (53→62), confirming the advantage of RS2 high temperature gelatinization characteristics (85-95°C) in delaying digestion (p<0.05).

[0140] Comparative Example 2 (ordinary starch): eGI value is 68, indicating that the lack of resistant starch leads to an increase in glycemic load, but it is still better than ordinary steamed bread (Comparative Example 1), which may be related to fiber components such as highland barley flour.

[0141] Test Example 2

[0142] Dietary fiber and protein content

[0143] Dietary fiber determination (GB 5009.88-2014):

[0144] Enzymatic hydrolysis: The sample is hydrolyzed by α-amylase, protease, and amyloglucosidase in sequence, and the residue is filtered, dried, and weighed;

[0145] Calculation formula: Dietary fiber (%) = (residue mass - ash mass - protein mass) / sample mass × 100%.

[0146] Protein determination (GB 5009.5-2016 Kjeldahl method):

[0147] Digestion: The sample is heated with concentrated sulfuric acid until the organic matter is decomposed and ammonium sulfate is produced;

[0148] Distillation titration: add NaOH to distill and release ammonia, absorb it with boric acid and then titrate with hydrochloric acid;

[0149] Calculation formula: Protein (%) = (V-V0) × C × 14 × 6.25 / m × 100% (V is the sample titration volume, V0 is the blank).

[0150] Statistics:

[0151] Each group was measured three times in parallel, and the results were retained to one decimal place;

[0152] The differences in dietary fiber and protein content were analyzed by t-test (p<0.01).

[0153] The results are shown in Table 4 and Figure 3 and Figure 4 .

[0154] Table 4 Dietary fiber and protein content

[0155]

[0156]

[0157] From the data in Table 4, we can see

[0158] Example 1 Dietary fiber (7.4g / 100g): Superfine highland barley flour (β-glucan ≥5%) and mulberry leaf high-fiber powder (dietary fiber ≥50%) contribute 68% of the total fiber content, which is significantly higher than ordinary steamed bread (2.1g / 100g).

[0159] Example 5 (ordinary highland barley flour): The dietary fiber content was reduced to 6.2 g / 100 g, indicating that the ultrafine grinding process improved the release efficiency of β-glucan (particle size D50≤20 μm).

[0160] Protein content (Example 1: 12.8 g / 100 g): gluten powder (75% protein) and bean powder (chickpea, Chinese yam) synergistically increase the plant protein content to meet the high protein needs of diabetic patients.

[0161] Test Example 3

[0162] Dynamic pH monitoring during fermentation

[0163] Method: pH meter real-time monitoring of fermentation stage

[0164] result:

[0165] Example 1: Initial pH 5.8 → pH 5.5 after the first stage of fermentation → Stabilized pH 5.2 in the second stage

[0166] Comparative Example 5: No pH control → Final pH 3.9 (over-acidification)

[0167] Conclusion: Staged fermentation and compound bacteria to precisely control pH

[0168] Test Example 4

[0169] Texture characteristics analysis

[0170] Standard basis: GB / T 35869-2018 "Grain and Oil Inspection-Testing of Rheological Properties of Wheat Flour Dough by Texture Analyzer Method".

[0171] Instrument parameters:

[0172] Probe: P / 36R cylindrical probe (36mm diameter);

[0173] Test mode: TPA (total texture analysis);

[0174] Parameters: compression rate 50%, test speed 1mm / s, trigger force 5g.

[0175] step:

[0176] The center of the steamed bun was cut into cubes (2 × 2 × 2 cm) and equilibrated at room temperature for 1 hour;

[0177] The hardness (peak force of the first compression, N) and elasticity (height recovered between two compressions, mm) were measured.

[0178] Data Analysis:

[0179] The differences in hardness and elasticity were analyzed by Kruskal-Wallis test (p<0.01).

[0180] The results are shown in Table 5 and Figure 5 and Figure 6 shown.

[0181] Table 5 Texture characteristics analysis results

[0182] Group Hardness(N) Elasticity(mm) Example 1 520 2.8 Comparative Example 3 890 1.5

[0183] From the data in Table 5, we can see that:

[0184] Example 1 Hardness (520N): The gradient cooling process (2.5°C / min→1°C / min) inhibited starch retrogradation, and the hardness was reduced by 42% (p<0.01) compared with Comparative Example 3 (890N).

[0185] Elasticity (2.8 mm): Staged fermentation (pH 5.5→5.2) maintained the dough network structure and increased elasticity by 87% (elasticity 1.5 mm in comparison example 3), approaching the palatability of traditional steamed bread.

[0186] Test Example 5

[0187] Postprandial blood glucose response in diabetic patients

[0188] Method: 50 patients with type 2 diabetes mellitus ate the steamed bread of Example 1 and Comparative Example 1 alternately, and the blood glucose AUC was measured.

[0189] result:

[0190] Example 1 group: 2h postprandial blood glucose peak value was reduced by 28% and AUC was reduced by 32% compared with the control group

[0191] (p<0.01)

[0192] Sensory score: Example 1 flavor acceptance reached 8.5 points (10 points)

[0193] Conclusion: The product is suitable for the dietary management of diabetes.

[0194] Test Example 6

[0195] Effects of sweeteners and fiber deficiency on GI values

[0196] Method: Same as test example 1, the in vitro starch hydrolysis index and eGI were determined.

[0197] The results are shown in Table 6.

[0198] Table 6 Effects of sweeteners and fiber deficiency on GI values

[0199] Group Starch hydrolysis index (%) eGI value Dietary fiber (g / 100g) Example 1 38％ 53 7.4 Comparative Example 6 43％ 58 8.2 Comparative Example 7 45％ 61 7.1 Comparative Example 8 51％ 66 6.8

[0200] in conclusion:

[0201] The absence of monk fruit concentrated juice resulted in an increase of 5 units in eGI (Comparative Example 6 vs Example 1), suggesting that its natural sweetener can delay the activity of digestive enzymes;

[0202] The lack of mulberry leaf high-fiber powder reduced dietary fiber by 1.4g / 100g, and the starch hydrolysis index increased significantly (Comparative Example 7 vs Example 1);

[0203] When both are missing, the eGI value approaches the high GI threshold (66), demonstrating that the two synergistically reduce glycemic load.

[0204] Test Example 7

[0205] Sensory evaluation and blood sugar response

[0206] method:

[0207] Sensory evaluation: 30 healthy subjects conducted a blind test on the steamed bread of Example 1, Comparative Example 6 and Comparative Example 8 (sweetness, roughness, palatability, 10 points);

[0208] Roughness rating: 1 = no graininess, 10 = very rough; Sweetness rating: 1 = no sweetness, 10 = very sweet

[0209] Blood sugar test: 10 diabetic patients ate 50g of carbohydrate equivalent of steamed bread, and the peak blood sugar level 2 hours after the meal was measured.

[0210] The results are shown in Table 7.

[0211] Table 7 Sensory evaluation and blood sugar response

[0212] Group Sweetness Rating Roughness score Peak blood glucose level (mmol / L) Example 1 7.8 6.5 7.2 Comparative Example 6 6.2 7.1 8.1 Comparative Example 8 5.5 8.3 8.9

[0213] in conclusion:

[0214] The lack of monk fruit juice concentrate resulted in a 22% drop in sweetness, and the additional addition of oligofructose still could not make up for the soft taste of natural sweeteners;

[0215] The absence of mulberry leaf high-fiber powder increased the roughness score, but the peak blood sugar level increased by 23% when both were missing, confirming their synergistic blood sugar-control effect.

[0216] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Therefore, based on the innovative concept of the present invention, changes and modifications to the embodiments described herein, or equivalent structures or equivalent process transformations made using the contents of the present invention specification, directly or indirectly applying the above technical solutions to other related technical fields are all included in the protection scope of the patent of the present invention.

Claims

1. A low glycemic index steamed bread premix powder, characterized in that: It is composed of the following raw materials in parts by weight: 30-40 parts of whole wheat flour, 25-35 parts of drinking water, 8-12 parts of raw soy milk, 6-8 parts of gluten, 4-6 parts of resistant starch, 3-5 parts of vegetable oil, 2-4 parts of highland barley flour, 1-2 parts of chickpea flour, 1-2 parts of yam powder, 0.5-1 parts of quinoa flour, 0.5-1 parts of oat bran powder, 0.5-1 parts of oligofructose, 0.5-0.8 parts of yeast, 0.2-0.5 parts of monk fruit concentrated juice, 0.2-0.5 parts of mulberry leaf high fiber powder, and 0.05-0.15 parts of lactic acid bacteria powder.

2. The low glycemic index steamed bread premix according to claim 1, characterized in that: The resistant starch is high-amylose corn resistant starch RS2 type, and the gelatinization temperature range is controlled at 85-95°C.

3. The low glycemic index steamed bread premix according to claim 1, characterized in that: The highland barley flour is whole highland barley flour with a beta-glucan content of ≥5% after ultrafine grinding.

4. The low glycemic index steamed bread premix according to claim 1, characterized in that: The compound lactic acid bacteria powder for food processing contains active bacterial groups of Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus casei, and the total number of live bacteria is ≥1×10^10 CFU / g.

5. A method for preparing low glycemic index steamed bread using the premix according to any one of claims 1 to 4, characterized in that The following steps are involved: (1) Preparation of premixed powder: dry-mix whole wheat flour, gluten powder, resistant starch, highland barley flour, chickpea flour, Chinese yam powder, quinoa powder, oat bran powder, and mulberry leaf high-fiber powder; (2) kneading: adding drinking water, raw soybean milk, non-GMO soybean oil, oligofructose, and monk fruit concentrated juice to the mixture of step (1), and kneading at 25-30° C. until dough is formed; (3) Fermentation: Add yeast and lactic acid bacteria powder, first ferment at 35-38°C for 40-50 minutes, then transfer to 28-30°C for 20-30 minutes; (4) Shaping and steaming: After the fermented dough is shaped, it is steamed in 100-105°C steam for 10-15 minutes.

6. The method according to claim 5, characterized in that During the fermentation process of step (3), the pH value of the dough is controlled to be maintained in the range of 5-6.

7. The method according to claim 5, characterized in that After steaming in step (4), a gradient cooling process is adopted: first cooling to 60°C at a rate of 2-3°C / min, and then cooling to room temperature at a rate of 1°C / min.

8. A steamed bread product prepared by the method of claim 5, characterized in that: The starch hydrolysis index of the steamed bread product is ≤40% in an in vitro simulated digestion test, and the estimated glycemic index eGI measured in a human experiment is ≤55.

9. The steamed bread product according to claim 8, characterized in that: The dietary fiber content in steamed bread products is ≥7g / 100g, and the protein content is ≥12g / 100g.

10. Use of the premixed powder according to any one of claims 1 to 4 or the steamed bread product according to any one of claims 8 to 9 in preparing a supplementary food for diabetes, characterized in that The food is suitable for the dietary management of patients with diabetes, obesity and hypertension.

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