A meal replacement powder composition with hypoglycemic activity and a preparation method thereof

Abstract

This invention relates to the field of food processing technology and discloses a meal replacement powder composition with hypoglycemic activity and its preparation method. The meal replacement powder uses buckwheat flour, yam flour, bitter melon flour, konjac oligosaccharide, polygonatum powder, and hawthorn powder as raw materials, with an optimized ratio of 2.00g buckwheat flour, 1.00g yam flour, 0.50g bitter melon flour, 0.40g konjac oligosaccharide, 0.40g polygonatum powder, and 0.45g hawthorn powder. The preparation method includes raw material pretreatment and precise ingredient mixing steps. The meal replacement powder of this invention is rich in total polysaccharides, total flavonoids, and total phenolic active ingredients. Its in vitro α-glucosidase inhibition rate is similar to that of acarbose, and its α-amylase inhibition rate is superior to that of acarbose. With a GI value of 53.92 (low GI food), it can effectively delay the rise in postprandial blood glucose, meeting the blood sugar control needs of people with prediabetes. The process is simple, the raw materials are natural, and it has the potential for large-scale industrialization.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and more specifically, to a meal replacement powder composition with hypoglycemic activity and its preparation method. Background Technology

[0002] Dietary intervention can significantly delay the onset of type 2 diabetes in people with prediabetes, and meal replacement powders have become a core carrier of dietary intervention due to their convenience and controllable nutrition. Existing meal replacement products mostly focus on nutritional supplementation, with fewer natural plant-based compound products targeting blood sugar regulation. These products often suffer from weak blood sugar control effects, high glycemic index (GI), and unreasonable formulations.

[0003] Buckwheat, yam, bitter melon, polygonatum, and hawthorn are all medicinal and edible ingredients, rich in hypoglycemic active components such as polysaccharides, flavonoids, and polyphenols; konjac oligosaccharides can encapsulate starch granules and delay carbohydrate digestion. While the hypoglycemic effect of a single ingredient is limited, a combination of these ingredients can achieve synergistic effects. Therefore, the development of a natural, safe, scientifically formulated meal replacement powder composition with excellent hypoglycemic activity and its preparation method has significant market value. Summary of the Invention

[0004] In view of this, the present invention proposes a meal replacement powder composition with hypoglycemic activity and its preparation method, aiming to solve the problems of weak blood sugar control effect, drastic postprandial blood sugar fluctuation, unscientific formula or poor synergy, unsafe long-term use and difficulty in industrialization of current meal replacement powders.

[0005] A meal replacement powder composition with hypoglycemic activity, comprising the following components in parts by weight: Buckwheat flour 2.00 parts, yam flour 0.6-1.2 parts, bitter melon flour 0.3-0.9 parts, konjac oligosaccharide 0.25-0.55 parts, polygonatum powder 0.25-0.55 parts, hawthorn powder 0.25-0.55 parts.

[0006] Furthermore, the viscosity of the konjac oligosaccharide is <100 mPa·s, and the effective polysaccharide content is 70%.

[0007] Furthermore, the buckwheat flour, yam flour, konjac oligosaccharide, and bitter melon flour are powders that have passed through an 80-mesh sieve; the polygonatum powder is powder that has passed through a 20-mesh sieve; and the hawthorn powder is powder that has passed through a 40-mesh sieve.

[0008] A method for preparing a meal replacement powder composition with hypoglycemic activity includes the following steps: (1) Raw material pretreatment: Buckwheat rice, dried iron yam slices and dried bitter melon were pulverized and passed through an 80-mesh sieve. Dried polygonatum was dry-ground into powder in several batches, cooled and passed through a 20-mesh sieve. Pitted dried hawthorn was pulverized and passed through a 40-mesh sieve. Konjac oligosaccharide was passed through an 80-mesh sieve to obtain the respective powders, which were then refrigerated and sealed for later use. (2) Mixing ingredients: Mix the powder thoroughly and evenly to obtain the meal replacement powder.

[0009] Furthermore, in step (1): the grinding time for buckwheat rice and dried iron yam slices is 2 minutes; the grinding time for dried bitter melon and pitted hawthorn is 1 minute; the grinding time for dried polygonatum is 1 minute each time, and the grinding is repeated 3 times.

[0010] This invention also protects the use of the above-mentioned meal replacement powder composition with hypoglycemic activity in the preparation of low-GI hypoglycemic meal replacement foods.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses a compound of medicinal and edible raw materials, including buckwheat, yam, bitter melon, konjac oligosaccharide, polygonatum, and hawthorn, which are rich in three major hypoglycemic active ingredients: total polysaccharides, total flavonoids, and total phenols. The multi-component combination synergistically regulates sugar metabolism, provides antioxidant effects, and slows down sugar absorption, thus solving the problems of weak hypoglycemic effect of single raw materials and unreasonable formula ratios.

[0012] This invention uses food-grade raw materials throughout the entire process, without any chemical hypoglycemic additives or excipients. It is natural, gentle, and has no side effects. It overcomes the shortcomings of chemical hypoglycemic products that are not suitable for long-term consumption and ordinary meal replacements that cannot balance safety and efficacy. It can be used as a daily blood sugar control meal replacement for people with prediabetes.

[0013] The formula of this invention was optimized through single-factor and orthogonal experiments. It was precisely compounded with α-glucosidase inhibition rate as the core indicator. Within the experimental concentration range, the difference between α-glucosidase inhibition rate and acarbose does not exceed 3.70%, and the α-amylase inhibition rate is better than acarbose with a difference of no more than 11.89%. It can effectively block the decomposition of carbohydrates, reduce glucose absorption from the source, and its hypoglycemic activity is far superior to that of ordinary nutritional meal replacements.

[0014] The meal replacement powder prepared by this invention has a GI value of 53.92, which is a low-GI food. In vitro simulated digestion shows that starch hydrolysis is slow and there is no sudden rise, which can effectively avoid drastic fluctuations in postprandial blood sugar and perfectly meet the core needs of people with prediabetes to control blood sugar steadily.

[0015] This invention can produce the finished product simply by crushing, sieving, and precisely mixing the raw materials. It does not require complex equipment or stringent process conditions. The production process is short and the cost is low. It solves the problems of complex existing sugar-controlled meal replacement processes and the difficulty of industrialization. It has the value of large-scale production and market promotion.

[0016] This invention can further deepen the synergistic hypoglycemic mechanism of multiple active ingredients, improve in vivo hypoglycemic verification tests, optimize formula ratios and processing technology, expand product dosage form development, and continuously improve the efficacy and safety evaluation of food ingredients by combining clinical follow-up data, thereby promoting the large-scale application of natural hypoglycemic meal replacement products. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram showing the effect of yam powder addition on α-glucosidase inhibition rate; Figure 2 A schematic diagram showing the effect of bitter melon powder addition on α-glucosidase inhibition rate; Figure 3 The effect of konjac oligosaccharide addition on α-glucosidase inhibition rate; Figure 4 The effect of the amount of Polygonatum sibiricum powder added on the α-glucosidase inhibition rate; Figure 5 The effect of hawthorn powder addition on α-glucosidase inhibition rate; Figure 6 These are the results of α-glucosidase inhibition rate determination of samples at different dilution ratios in the embodiments of this application; Figure 7 The α-amylase inhibition rate of the samples at different dilution ratios in the embodiments of this application; Figure 8 The figures represent the starch hydrolysis rate of samples at different dilution ratios during simulated digestion in vitro, as described in the embodiments of this application. Detailed Implementation

[0018] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0019] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0020] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0021] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0022] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0023] Unless otherwise specified, "parts" in this invention refer to parts by weight. In the following examples, the raw materials are weighed according to 1 part = 1g.

[0024] A meal replacement powder composition with hypoglycemic activity, comprising the following components in parts by weight: Buckwheat flour 2.00 parts, yam flour 1.00 parts, bitter melon flour 0.50 parts, konjac oligosaccharide 0.40 parts, polygonatum powder 0.40 parts, hawthorn powder 0.45 parts.

[0025] Furthermore, the viscosity of the konjac oligosaccharide is <100 mPa·s, and the effective polysaccharide content is 70%.

[0026] Furthermore, the buckwheat flour, yam flour, konjac oligosaccharide, and bitter melon flour are powders that have passed through an 80-mesh sieve; the polygonatum powder is powder that has passed through a 20-mesh sieve; and the hawthorn powder is powder that has passed through a 40-mesh sieve.

[0027] A method for preparing a meal replacement powder composition with hypoglycemic activity includes the following steps: (1) Raw material pretreatment: Buckwheat rice, dried iron yam slices and dried bitter melon were pulverized and passed through an 80-mesh sieve. Dried polygonatum was dry-ground into powder in several batches, cooled and passed through a 20-mesh sieve. Pitted dried hawthorn was pulverized and passed through a 40-mesh sieve. Konjac oligosaccharide was passed through an 80-mesh sieve to obtain the respective powders, which were then refrigerated and sealed for later use. (2) Mixing ingredients: Mix the powder thoroughly and evenly to obtain the meal replacement powder.

[0028] Furthermore, in step (1): the grinding time for buckwheat rice and dried iron yam slices is 2 minutes; the grinding time for dried bitter melon and pitted hawthorn is 1 minute; the grinding time for dried polygonatum is 1 minute each time, and the grinding is repeated 3 times.

[0029] This invention also protects the use of the above-mentioned meal replacement powder composition with hypoglycemic activity in the preparation of low-GI hypoglycemic meal replacement foods.

[0030] In this invention, unless otherwise specified, all raw materials required for preparation are commercially available products well known to those skilled in the art.

[0031] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0032] Example 1 Take appropriate amounts of buckwheat rice and dried Chinese yam slices, and grind them into powder for 2 minutes in the dry grinding cup of a high-speed blender. After the powder cools, pass it through an 80-mesh sieve and pour it into a food-grade sealed bag. Store it in the refrigerator in an airtight container for later use. Take appropriate amounts of dried bitter melon, and grind it into powder for 1 minute in the dry grinding cup of a high-speed blender. After the bitter melon powder cools, pass it through an 80-mesh sieve and pour it into a food-grade sealed container. Store it in the refrigerator in an airtight container for later use. Take appropriate amounts of dried polygonatum, and grind it into powder for 1 minute each time in the dry grinding cup of a high-speed blender. Repeat this process 3 times. After the polygonatum powder cools, pass it through a 20-mesh sieve and pour it into a food-grade sealed bag. Add a food-grade silica gel desiccant packet and store it in the refrigerator in an airtight container for later use. Take appropriate amounts of pitted dried hawthorn, and grind it into powder for 1 minute in the dry grinding cup of a high-speed blender. After the hawthorn powder cools, pass it through a 40-mesh sieve and pour it into a food-grade sealed bag. Store it in the refrigerator in an airtight container for later use. Pass konjac oligosaccharide through an 80-mesh sieve and pour it into a food-grade sealed bag. Store it in the refrigerator in an airtight container for later use.

[0033] Example 2 Using 2.00g of buckwheat flour, the amounts of yam flour, bitter melon flour, konjac oligosaccharide, polygonatum powder, and hawthorn powder were varied. The dry powders were repeatedly inverted and then poured back into the test tube 5-10 times to mix evenly before the α-glucosidase inhibition rate was determined.

[0034] (1) Effect of yam powder addition on α-glucosidase inhibition rate Weigh out 2.00g, 0.60g, 0.40g, 0.40g, and 0.40g of buckwheat flour, bitter melon flour, konjac oligosaccharide, polygonatum powder, and hawthorn powder, respectively. Determine the effect of the amount of yam powder added (0.60g, 0.70g, 0.80g, 0.90g, 1.00g, 1.10g, and 1.20g) on ​​the α-glucosidase inhibition rate of the meal replacement powder, and determine the optimal amount of yam powder added.

[0035] Depend on Figure 1It was found that the inhibition rate of α-glucosidase activity showed a pattern of first significantly increasing and then continuously decreasing with the addition of yam powder. When the amount of yam powder added was in the range of 0.6~0.9g, the inhibition rate increased rapidly with the increase of the amount added, reaching a peak of 70.83% when the amount of yam powder added was 0.9g. When the amount added exceeded 0.9g, the inhibition rate showed an overall decreasing trend. The results indicate that 0.9g of yam powder was the optimal amount added under the experimental conditions. Excessive addition could not continuously improve the inhibitory effect, but instead reduced the activity. This may be because yam is rich in starch and mucin, and the increase in yam concentration affected the fluidity of the enzyme hydrolysis system, as well as the competition between high concentration substrate and inhibitor for enzyme reaction. Therefore, orthogonal experiments were conducted with yam powder addition amounts of 0.7g, 0.8g, 0.9g, and 1.0g.

[0036] (2) Effect of bitter melon powder addition on α-glucosidase inhibition rate After determining the optimal amount of yam powder to be added, 2.00g, 0.40g, 0.40g, and 0.40g of buckwheat powder, konjac oligosaccharide, polygonatum powder, and hawthorn powder were weighed, respectively. The effects of bitter melon powder addition amounts (0.30g, 0.40g, 0.50g, 0.60g, 0.70g, 0.80g, and 0.90g) on ​​the α-glucosidase inhibition rate of the meal replacement powder were measured to determine the optimal amount of bitter melon powder to be added.

[0037] Depend on Figure 2 The results showed that the inhibition rate of α-glucosidase activity increased significantly with increasing bitter melon powder dosage within the range of 0.3–0.5 g, reaching a peak of 77.71% at 0.5 g. When the dosage exceeded 0.5 g, the inhibition rate showed a continuous downward trend, rapidly decreasing in the 0.5–0.7 g range and steadily decreasing further in the 0.7–0.9 g range. These results indicate that both excessively low and excessively high amounts of bitter melon powder are detrimental to improving the inhibition rate. Appropriate dosage of bitter melon powder yields the best results, while excessive dosage produces an inhibitory effect. This may be because increased bitter melon powder dosage leads to higher cellulose concentration and viscosity, affecting the contact between the enzyme and the inhibitor. Under the conditions of this experiment, the optimal dosage of bitter melon powder was 0.5 g. Therefore, orthogonal experiments were conducted with dosages of 0.4 g, 0.5 g, 0.6 g, and 0.7 g.

[0038] (3) Effect of konjac oligosaccharide addition on α-glucosidase inhibition rate After determining the optimal amounts of yam powder and bitter melon powder, 2.00g, 0.40g, and 0.40g of buckwheat powder, polygonatum powder, and hawthorn powder were weighed, respectively. The effects of the amounts of konjac oligosaccharide added (0.25g, 0.30g, 0.35g, 0.40g, 0.45g, 0.50g, and 0.55g) on ​​the α-glucosidase inhibition rate of the meal replacement powder were determined, and the optimal amount of konjac oligosaccharide added was determined.

[0039] Depend on Figure 3 It can be seen that the inhibition rate of α-glucosidase activity continuously increases with the increase of konjac oligosaccharide addition in the range of 0.3~0.5g, reaching a maximum of 66.10% at the 0.4g addition level, showing the best enzyme activity inhibition effect. When the addition amount exceeds 0.4g, the inhibition effect drops significantly, showing an overall downward trend.

[0040] The optimal addition amount of konjac oligosaccharide in this experimental system was 0.4g. Adding too little or too much konjac oligosaccharide failed to guarantee the best effect. This may be because konjac oligosaccharide reduces α-amylase activity by forming a sol that encapsulates starch granules. However, at excessively high concentrations, the sol itself becomes entangled, failing to effectively encapsulate starch granules and thus reducing its inhibitory effect. Therefore, orthogonal experiments were conducted using konjac oligosaccharide addition amounts of 0.3g, 0.35g, 0.4g, and 0.45g.

[0041] (4) Effect of Polygonatum sibiricum powder addition on α-glucosidase inhibition rate After determining the optimal amounts of yam powder, bitter melon powder, and konjac oligosaccharide, 2.00g of buckwheat powder and 0.40g of hawthorn powder were weighed out. The effects of the amounts of polygonatum powder added (0.25g, 0.30g, 0.35g, 0.40g, 0.45g, 0.50g, and 0.55g) on ​​the α-glucosidase inhibition rate of the meal replacement powder were determined to identify the optimal amount of polygonatum powder added.

[0042] Depend on Figure 4 It was found that when the amount of Polygonatum added was in the range of 0.25~0.4g, the inhibition rate of α-glucosidase activity in the system continuously increased with the increase of dosage, reaching a peak of 77.33% at the 0.4g addition level, at which point the inhibitory activity against the target substance was at its optimal state. When the addition amount exceeded 0.4g, the inhibitory effect showed a significant decline, showing an overall trend of first increasing and then decreasing. In the early low-dose stage, the active ingredients such as polysaccharides and saponins in Polygonatum gradually dissolved and formed a good synergistic effect with the system; in the later stage, when excessive addition was added, the high substrate concentration may have caused antagonistic effects between components, resulting in a significant decrease in inhibitory ability. Comprehensive analysis shows that too low a dosage of Polygonatum cannot fully exert its efficacy, while too high a dosage is counterproductive. Under the conditions of this experiment, 0.4g is the optimal dosage. Therefore, orthogonal experiments were conducted with Polygonatum addition amounts of 0.3g, 0.35g, 0.4g, and 0.45g.

[0043] (5) Effect of hawthorn powder addition on α-glucosidase inhibition rate After determining the optimal amounts of yam powder, bitter melon powder, konjac oligosaccharide, and polygonatum powder, 2.00g of buckwheat powder was weighed, and the effects of hawthorn powder additions (0.25g, 0.30g, 0.35g, 0.40g, 0.45g, 0.50g, and 0.55g) on ​​the α-glucosidase inhibition rate of the meal replacement powder were measured to determine the optimal amount of hawthorn powder added.

[0044] Depend on Figure 5 The results showed that when the amount of hawthorn added was in the range of 0.25~0.45g, the inhibition rate of α-glucosidase activity steadily increased with the increase of dosage, reaching a peak of 73.9% at the 0.45g addition level, at which the system's enzyme activity inhibition ability was optimal. When the addition amount exceeded 0.45g, the inhibition rate decreased with the increase of dosage, showing a rapid decreasing trend in the 0.5~0.55g range. This indicates that further increasing the amount of hawthorn did not continue to improve the effect, but instead caused a significant decline. This may be because the increased hawthorn concentration led to a deviation from the optimal pH of α-glucosidase, and the increased system viscosity was caused by the increased sugar concentration.

[0045] The results showed that 0.45g was the optimal addition amount under the experimental conditions. Controlling the addition amount of hawthorn in a lower range around 0.45g was more conducive to maintaining a good inhibitory effect. Therefore, orthogonal experiments were conducted to analyze the addition amounts of hawthorn of 0.35g, 0.40g, 0.45g, and 0.50g.

[0046] Example 3 Based on the results of single-factor experiments, using the inhibition rate of α-glucosidase activity as an indicator, the addition amounts of yam powder (A), bitter melon powder (B), konjac oligosaccharide (C), polygonatum powder (D), and hawthorn powder (E) were selected as the factors for investigation. L 16 (4 5 An orthogonal experiment was conducted to optimize the meal replacement powder formula. The factor level table for the orthogonal experiment is shown in Table 1.

[0047]

[0048] The results of the above orthogonal experiments are shown in Table 2 below. Table 2 Results of Orthogonal Experiments

[0049] Table 2 shows that the order of influence of the five factors on the inhibition rate of α-glucosidase activity in meal replacement powder is A>B>C>E>D. The optimal combination is A4B2C3D3E, which means that if the amount of buckwheat flour added is 2.0g, then the amount of yam flour added is 1.0g, bitter melon flour added is 0.5g, konjac oligosaccharide added is 0.4g, polygonatum powder added is 0.4g, and hawthorn powder added is 0.45g.

[0050] The optimized formulation, obtained through orthogonal experiments, showed α-glucosidase activity inhibition rates of 78.10%, 79.62%, and 78.86% in three repeated experiments, with an average of 78.86% ± 0.76%. These values ​​were higher than the highest values ​​in both single-factor and orthogonal experiments, indicating that the optimization results are reliable.

[0051] Example 4 (1) The α-glucosidase inhibition rate was determined by weighing 0.2g of meal replacement powder sample into a centrifuge tube, adding 20mL of phosphate buffer with pH=6.8, vortexing, sonicating at 40℃ for 15min, centrifuging at 4000r / min for 10min, and then taking the supernatant and diluting it 4 times for later use.

[0052] Add 25 μL of pH 6.8 phosphate buffer, 25 μL of 0.40 U / ml α-glucosidase solution, and 25 μL of sample solution sequentially to the microplate. After shaking and mixing thoroughly, incubate at 37°C for 15 min. Then add 20 μL of 0.0116 mol / L pNPG solution, shake and mix thoroughly, and incubate at 37°C for 20 min. Finally, add 100 μL of 0.20 mol / L sodium carbonate solution to terminate the reaction. Measure the absorbance at 405 nm and calculate the α-glucosidase activity inhibition rate of the sample using the following formula.

[0053] E inhibition rate = [A blank - (A sample - A background)] ÷ A blank × 100% In the formula: A blank: absorbance value after the reaction without adding sample. Sample A: Absorbance after the sample has reacted. Background A: Absorbance of sample without enzyme.

[0054] (2) Determination of active ingredients: ①Total phenol determination: Weigh 0.01g of gallic acid and dilute to volume in a 50mL volumetric flask to prepare a 0.2mg / mL gallic acid stock solution. Take 0, 0.2, 0.4, 0.6, 0.8, and 1.0mL of this stock solution into 10mL graduated test tubes, add 60% ethanol solution to 1mL, then add 2.5mL of Folin-Ciocalteu reagent and 2.5mL of 15% sodium carbonate solution, dilute to the mark with water, shake well, and let stand at room temperature for 2h. Measure the absorbance at 760nm and plot a standard curve.

[0055] Weigh 0.3g of the optimal formula meal replacement powder sample into 9mL of 60% ethanol, vortex, sonicate for 2 hours, extract overnight in the dark, and combine the extracts after three extractions. The next day, centrifuge at 5000r / min for 20min and collect the supernatant to prepare the sample test solution. Replace gallic acid stock solution with 1.0mL of the sample test solution and repeat the standard curve determination procedure. Finally, calculate the total phenol content in the meal replacement powder based on the fitted standard curve. The standard curve equation is y=173.69x+0.1215, R0. 2 =0.9991.

[0056] ② Determination of total flavonoids: Measure 0, 1, 2, 3, 4, 5, and 6 mL of rutin methanol solution (0.2968 mg / mL) into 25 mL stoppered glass test tubes, add 1 mL of 5% NaNO2 solution to each, shake well, and let stand for 6 min. Then add 1 mL of 10% Al(NO3)3 solution, shake well, and let stand for 6 min. Add 10 mL of 2% NaOH solution, and dilute to 25 mL with water. Shake well and incubate in a water bath at 40℃ for 30 min. Measure the absorbance at 510 nm to plot a standard curve. Weigh 1 g of the sample into 25 mL of methanol, extract ultrasonically for 30 min, centrifuge at 5000 r / min for 10 min, take 1 mL of the supernatant, and determine the absorbance according to the standard curve establishment method. Finally, calculate the total flavonoid content in the meal replacement powder based on the fitted standard curve. The standard curve equation is y = 9.822x - 0.0075, R0. 2 =999.

[0057] ③ Determination of total polysaccharides: Measure 0, 0.2, 0.4, 0.6, 0.8, and 1.0 mL of glucose standard solution (1 mg / mL) into 25 mL stoppered glass test tubes, add 1 mL of 5% phenol solution to each, shake well, then add 5 mL of concentrated sulfuric acid, shake well, dilute with water to 25 mL, and immediately place in a boiling water bath for 15 min. After cooling to room temperature, measure the absorbance at 490 nm to plot a standard curve. Weigh 1 g of meal replacement powder sample into 30 mL of water, boil in a water bath for 2 h, centrifuge, then measure 1 mL of the supernatant, add 4 mL of ethanol, vortex to mix, and let stand overnight at 4℃. The next day, centrifuge at 5000 r / min for 15 min, discard the supernatant, dissolve the precipitate in 5 mL of water, vortex to mix, and measure the absorbance according to the standard curve method to calculate the total polysaccharide content in the meal replacement powder. The standard curve equation is y = 1.9083x - 0.0024, R 2 =994.

[0058] The results of the determination of the active ingredients in the meal replacement powder of the present invention are shown in Table 3 below. Table 3 Results of determination of active ingredients in meal replacement powder

[0059] As shown in Table 3, among the three active ingredients, the total polysaccharide content was relatively the highest, and the total flavonoids also accounted for a relatively high proportion, while the total phenolic content was relatively low. In in vitro studies of the hypoglycemic activity of natural food ingredients, polysaccharides, flavonoids, and polyphenols are all key functional substances. Polysaccharides can regulate intestinal glucose metabolism and delay glucose absorption, while flavonoids and phenolic substances have excellent antioxidant capabilities and synergistically inhibit the activity of enzymes related to glucose metabolism. All three together support the hypoglycemic physiological activity of the samples.

[0060] (3) In vitro hypoglycemic activity α-glucosidase inhibition rate determination: Prepare a 10 mg / mL meal replacement powder sample solution. After vortexing, sonicate at 40℃ for 15 min, centrifuge at 4000 r / min for 10 min, and use the supernatant as the sample preparation solution. Dilute each sample preparation solution in a gradient of 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, and 1:4 to prepare sample solutions of different concentrations. Measure the absorbance of the sample solutions of different concentrations using the same method as for determining the hypoglycemic ability of meal replacement powder. Perform three replicates for each sample, with acarbose as a positive control group. Prepare a 10 mg / mL acarbose solution and dilute it accordingly to determine the inhibition rate.

[0061] Depend on Figure 6 The results showed that acarbose generally had a higher α-glucosidase activity inhibition rate than meal replacement powder. Only at a 1:1.5 dilution ratio was the inhibition rate of meal replacement powder slightly higher than that of acarbose. At low dilution ratios, the activity difference between the two was small. As the concentration decreased, the inhibition rate of meal replacement powder declined significantly, and the activity decayed faster. Within the experimental gradient range, the difference in inhibition rates between the two remained within 3.70%. Overall, meal replacement powder has considerable potential for in vitro hypoglycemic effects.

[0062] α-Amylase inhibition rate determination: A 10 mg / mL sample solution was prepared using the same method as for α-glucosidase inhibition rate determination. Different concentrations of sample solutions were prepared by gradient dilution at ratios of 1:1.5, 1:2, 1:2.5, 1:3, and 1:3.5. Acarbose was used as a positive control group; a 10 mg / mL acarbose solution was prepared and diluted accordingly to determine the inhibition rate. Add 25 μL of sample solutions of different concentrations and 25 μL of α-amylase solution (9 U / mL) to the microplate, shake to mix thoroughly, and incubate at 37°C for 15 min; then add 25 μL of 1% soluble starch solution, shake to mix thoroughly, and incubate at 37°C for 15 min; finally add 25 μL of DNS chromogenic reagent, place the mixture in a 100°C water bath for 15 min, and measure the absorbance at a wavelength of 540 nm. Calculate the α-amylase inhibition rate using the following formula.

[0063] α-Amylase inhibition rate = [A0 - (A2 - A1)] ÷ A0 × 100%; In the formula: A0: PBS buffer instead of the absorbance of the sample solution; A1: Absorbance of PBS buffer instead of α-amylase solution; A2: Absorbance of each sample.

[0064] Depend on Figure 7 The results showed that within the dilution range of 1:1.5 to 1:2, the enzyme inhibition rates of both groups of samples increased rapidly, reaching peak activity at a 1:2 ratio. As the concentration of the effective active substance decreased, the inhibitory activities of both groups steadily declined, exhibiting an overall concentration response pattern of first increasing and then decreasing. Across the entire concentration gradient, the α-amylase inhibitory ability of the meal replacement powder was consistently significantly higher than that of acarbose, with a maximum inhibition rate approaching 95%, and the maximum difference in inhibition rates between the two did not exceed 11.89%, demonstrating excellent in vitro hypoglycemic potential. Actual experiments also clearly showed that the meal replacement powder exhibited a significant activity advantage at low dilutions, while maintaining a stable α-amylase inhibitory effect even at high dilutions.

[0065] (4) Glycemic index measurement The reducing sugar content was determined using the 3,5-dinitrosalicylic acid method, with appropriate modifications. For the construction of the glucose standard curve: 0, 0.2, 0.4, 0.6, 0.8, and 1.0 mL of 1 mg / mL glucose standard solution were respectively pipetted into 10 mL stoppered graduated test tubes. Water was added to a final volume of 2.0 mL, followed by the addition of 4.0 mL of 3,5-dinitrosalicylic acid reagent. The tubes were incubated in a boiling water bath for 5 min, then cooled to room temperature. After dilution to volume, the solution was vortexed and mixed thoroughly. The absorbance was measured at 540 nm. A standard curve was plotted based on the absorbance values, and a regression equation was fitted. The standard curve equation was y = 6.8918x - 0.0177, R0. 2 =9992.

[0066] Simulated oral digestion stage: Add 9 mL of phosphate buffer and 1 mL of α-amylase (750 U / mL) to a test tube, shake well, preheat in a 37°C water bath, then add 10 mg of meal replacement powder (containing approximately 1.3 mg of starch) and vortex to mix. Digest in a 37°C water bath for 2 min, then immediately mix and collect the sample to be tested. Simulated gastric digestion stage: Take 1 mL of the sample to be tested and add 10 mL of citrate-sodium citrate buffer (0.1 mol / mL pH=3.0) to glucose solution, shake well, then add 0.2 mL of pepsin solution (2 mg / mL), and digest in a 37°C water bath for 2 h. Simulated intestinal digestion stage: Add 1 mL of α-amylase (10 U / mL), adjust the pH to 7.0 with 1 mol / mL sodium hydroxide solution, and continue digestion in a constant temperature water bath at 37℃. Take 1 mL samples at 0, 10, 20, 40, 60, 90, 120, and 180 min, immediately inactivate with boiling water, and determine the amount of reducing sugar generated using the DNS method. Calculate the starch hydrolysis rate of the sample according to formula (1), and calculate the glucose solution hydrolysis rate according to formula (2). Starch hydrolysis rate (%) = (C t -C0)×14×0.9 / 1.3×100% Equation (1); Glucose hydrolysis rate (%) = (C t -C0)×(0.0714-C0)×100% Equation (2); In the formula: C t : Glucose concentration (mg / mL) in the reaction solution at intestinal digestion time t; C0: Glucose concentration (mg / mL) in the reaction solution at 0 min of intestinal digestion; A hydrolysis rate curve was plotted with hydrolysis time on the x-axis and starch hydrolysis rate on the y-axis. The area under the hydrolysis rate curve (AUC) was obtained using Origin 2024 software, and the starch hydrolysis index (HI, %) of the sample was calculated according to the following formula: HI = AUC (sample) / AUC (glucose) 1.3 × 100%; Finally, based on the high correlation between HI and GI (r=0.826), the sample GI value was calculated as: GI=0.862HI+8.1981.

[0067] Depend on Figure 8It can be seen that with the continuous extension of the in vitro simulated digestion time, the starch hydrolysis rate of the sample showed a continuous upward trend. The starch hydrolysis rate was relatively fast in the 0-90 min range, with the hydrolysis rate rapidly climbing to 66.10%. After 90 min, the reaction rate gradually slowed down, and the hydrolysis curve tended to flatten, reaching a peak of 78.05% at 180 min. The sample starch exhibited significant slow-release digestion characteristics, without a rapid rise in glycemic index even under prolonged digestion. This result supports the sample's advantage of smooth carbohydrate release and delayed postprandial blood glucose fluctuations. The GI value of the meal replacement powder, calculated using the formula, was 53.92, with a glycemic index less than 55, classifying it as a low-GI food.

[0068] Based on the results of single-factor and orthogonal experiments, using the α-glucosidase activity inhibition rate as an indicator, the optimal formula for the product was determined to be 2.0g buckwheat flour, 1.0g yam flour, 0.5g bitter melon flour, 0.4g konjac oligosaccharide, 0.4g polygonatum powder, and 0.45g hawthorn powder. The meal replacement powder prepared under this formula had a total phenolic content of 0.45±0.02mg / g, a total flavonoid content of 3.96±0.10mg / g, and a total polysaccharide content of 5.77±0.28mg / g. The highest α-glucosidase activity inhibition rate was 92.59%, which was similar to the inhibition rate of the positive control group. The highest α-amylase activity inhibition rate was 94.82%, which was slightly higher than the inhibition rate of the positive control group. The GI value was 53.92, confirming the product as a low-GI food.

[0069] In summary, this invention clarifies that the sample is rich in total polysaccharides and total flavonoids, which are characteristic active substances that can effectively inhibit the activity of α-glucosidase and α-amylase. It also possesses the characteristic of slow-release starch digestion, achieving a stable blood sugar control effect through the synergistic effect of multiple components. Compared with clinical hypoglycemic drugs, this meal replacement powder also exhibits excellent enzyme inhibitory activity at appropriate concentrations. It is natural, mild, and has no side effects, making it suitable for long-term dietary intervention for blood sugar control. It has broad industrialization prospects in the field of health management for prediabetic populations.

[0070] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is determined by the appended claims.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A meal replacement powder composition with hypoglycemic activity, characterized in that, The components comprise the following parts by weight: Buckwheat flour 2.00 parts, yam flour 1.00 parts, bitter melon flour 0.50 parts, konjac oligosaccharide 0.40 parts, polygonatum powder 0.40 parts, hawthorn powder 0.45 parts.

2. The meal replacement powder composition with hypoglycemic activity according to claim 1, characterized in that, The viscosity of the konjac oligosaccharide is <100 mPa·s, and the effective polysaccharide content is 70%.

3. The meal replacement powder composition with hypoglycemic activity according to claim 1, characterized in that, The buckwheat flour, yam flour, konjac oligosaccharide, and bitter melon flour are powders that have passed through an 80-mesh sieve; the polygonatum powder is powder that has passed through a 20-mesh sieve; and the hawthorn powder is powder that has passed through a 40-mesh sieve.

4. A method for preparing a meal replacement powder composition with hypoglycemic activity as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Raw material pretreatment: Buckwheat rice, dried iron yam slices and dried bitter melon were pulverized and passed through an 80-mesh sieve. Dried polygonatum was dry-ground into powder in several batches, cooled and passed through a 20-mesh sieve. Pitted dried hawthorn was pulverized and passed through a 40-mesh sieve. Konjac oligosaccharide was passed through an 80-mesh sieve to obtain the respective powders, which were then refrigerated and sealed for later use. (2) Mixing ingredients: Mix the powder thoroughly and evenly to obtain the meal replacement powder.

5. The method for preparing a meal replacement powder composition with hypoglycemic activity according to claim 4, characterized in that, In step (1): the grinding time for buckwheat rice and dried iron yam slices is 2 minutes; the grinding time for dried bitter melon and pitted dried hawthorn is 1 minute; the grinding time for dried polygonatum is 1 minute each time, and the grinding is repeated 3 times.

6. The application of a meal replacement powder composition with hypoglycemic activity as described in claim 1, characterized in that, The specific application is the use of the meal replacement powder in the preparation of low-GI hypoglycemic meal replacement foods.

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