Low glycemic index solid beverage and preparation method and application thereof

Abstract

The present application relates to the technical field of functional food preparation and development of medicinal and edible resources, and particularly relates to a low glycemic index solid beverage and a preparation method thereof. 5% NaHCO3 solution combined with high-temperature rehydration significantly reduces the rehydration time of soapberry rice. Vacuum freeze-drying combined with powdering technology solves the problem of difficult powdering of soapberry rice. The present application designs a healthy food which can meet the consumers' demand for sweetness and relieve the increase of blood sugar by using soapberry rice powder as the main raw material and adding erythritol, pueraria powder, whey protein powder, barley powder, apple powder and other high-quality raw materials.

Description

Technical Field

[0001] This invention relates to the field of functional food preparation and the development of medicinal and edible resources, specifically a low glycemic index solid beverage and its preparation method and application. Background Technology

[0002] Dietary energy is central to weight management and blood sugar control. Weight management helps improve insulin resistance and blood sugar control. Diabetic patients or those with impaired blood sugar regulation, due to an absolute or relative deficiency of insulin, cannot fully exert their role in promoting glycogen, protein, and fat synthesis and inhibiting breakdown. This leads to poor blood sugar control and excessive breakdown of body fat and protein. A scientifically sound and appropriately proportioned supply of dietary nutrients is a strong guarantee for maintaining healthy blood sugar. The "Dietary Guidelines for Adults with Diabetes (2023 Edition)" recommends that "the macronutrients in the diet of diabetic patients should account for the following proportions of total energy: protein 15%-20%, carbohydrates 45%-60%, and fat 20%-30%." The "Nutrition and Exercise Guidelines for Hyperglycemia (2024 Edition)" points out that hyperglycemic patients should "increase their dietary fiber intake, ideally 25g-30g per day." Dietary structure is a crucial factor affecting blood sugar fluctuations.

[0003] Soapberry rice is a local specialty food of Guizhou Province. Rich in polysaccharides and dietary fiber, it possesses antioxidant properties and can help alleviate type 2 diabetes and improve ulcerative colitis. Currently, soapberry rice is mostly sold as an agricultural product, with limited development of high-value-added products.

[0004] Therefore, it is necessary to use Guizhou's local specialty, soapberry rice, as a material basis to study its powdering process and develop a portable and easy-to-eat solid beverage suitable for people with abnormal blood sugar levels, with a reasonable macronutrient composition. Summary of the Invention

[0005] To address the aforementioned technical problems in the existing technology, this invention provides a low glycemic index solid beverage, its preparation method, and its application. Specifically, this is achieved through the following technical solution: A low glycemic index solid beverage is composed of the following ingredients: erythritol, kudzu root powder, saponin rice powder, whey protein powder, highland barley powder, and apple powder.

[0006] Furthermore, it is composed of the following raw materials: 40-60 parts erythritol, 15-20 parts kudzu root powder, 10-15 parts saponin rice powder, 5-7 parts whey protein powder, 5-7 parts highland barley powder, and 5-7 parts apple powder.

[0007] Furthermore, it is composed of the following ingredients: 50 parts erythritol, 18.75 parts kudzu root powder, 12.55 parts saponin rice powder, 6.25 parts whey protein powder, 6.25 parts highland barley powder, and 6.25 parts apple powder.

[0008] Furthermore, the soapberry rice flour is prepared by the following method: soaking one-times volume of soapberry rice in 20-40 times the volume of 5% sodium hydroxide solution, rehydrating at 100°C, freeze-drying using vacuum freeze-drying technology, and then grinding into powder to obtain soapberry rice flour.

[0009] A method for preparing soapberry rice flour includes the following steps: (1) rehydration: soaking soapberry rice in sodium hydroxide solution; (2) crushing; (3) freeze drying; (4) grinding into powder.

[0010] Furthermore, the rehydration process involves soaking 1 part of saponin rice in a 20-40 times sodium hydroxide solution.

[0011] Furthermore, the sodium hydroxide solution is a 4-6% sodium hydroxide solution, preferably 5%.

[0012] Furthermore, the rehydration of (1) is achieved by soaking 1 part of saponin rice in 20-40 times the amount of sodium hydroxide solution.

[0013] Furthermore, the rehydration process (1) is carried out at a temperature of 90-100°C, preferably 100°C.

[0014] Furthermore, the rehydration of (1) takes 3-4 hours.

[0015] Furthermore, the (2) crushing refers to draining excess water after rehydration and crushing particles with a diameter of 3-5 mm or not crushing at all.

[0016] Furthermore, the drying process (3) is freeze drying, which is divided into three stages: a. Pre-freezing: the pre-freezing temperature is -45 to -50℃; b. First drying: the drying temperature is -40 to 0℃; c. Second drying: the drying temperature is 10 to 50℃; the pre-freezing time is 3 to 5 hours; the first drying time is 10 to 16 hours; and the second drying time is 12 to 16 hours.

[0017] Furthermore, the pre-freezing time is preferably 4 hours.

[0018] Furthermore, the drying time is preferably 14 hours.

[0019] Furthermore, the secondary drying time is preferably 14 hours.

[0020] More preferably, the vacuum degree of the primary drying is 0 to 0.2 mbar.

[0021] The specific parameters for the above freeze-drying are as follows: pre-vacuum 0.2 mbar, alarm vacuum 0.8 mbar, alarm vacuum duration 300 s, and freeze control, primary drying, and desorption drying parameters are as follows: freeze-drying parameters

[0022] Compared with the prior art, the technical effects of this invention are reflected in: This application describes a process for producing soapberry rice flour using alkaline rehydration, crushing, vacuum freeze-drying, and milling. The use of 5% NaHCO3 solution combined with high-temperature rehydration significantly reduces the rehydration time of the soapberry rice, while vacuum freeze-drying combined with milling solves the problem of difficult milling. Based on the concept of balanced nutrition, soapberry rice flour is used as the main ingredient, supplemented with high-quality ingredients such as erythritol, kudzu root powder, whey protein powder, highland barley powder, and apple powder. This product is designed to satisfy consumers' craving for sweetness while also mitigating blood sugar spikes. Test results show that the product has low fat content (0.7 g / 100g) and low energy (742 kJ / 100g), while being high in dietary fiber (11.64 g / 100g) and protein (6.74 g / 100g). Human trials indicate that the product has a glycemic index below 55 and a glycemic load below 10, classifying it as a low-glycemic index food suitable for people with high blood sugar. This product offers a balanced diet with moderate energy, low fat, and abundant dietary fiber, making it a healthy choice. It also addresses the issue of limited downstream products made from saponin rice. Attached Figure Description

[0023] Figure 1 This is a radar chart of the amino acid score of the raw materials. (A) FAO / WHO (1973) reference mode, (B) FBN / IOM (2002) reference mode.

[0024] Figure 2 This refers to the change in the water absorption of soapberry rice over time at different temperatures.

[0025] Figure 3 These are rehydration diagrams of soapberry rice. (A) Rehydration diagram of soapberry rice; (B) Rehydration diagram of a single soapberry rice grain.

[0026] Figure 4 This relates to the effect of adding sodium bicarbonate on the rehydration time of saponin rice.

[0027] Figure 5 It is the blood glucose response curve of glucose and the food to be tested. Detailed Implementation

[0028] The technical solution of the present invention will be further defined below with reference to specific embodiments, but the scope of protection is not limited to the description made.

[0029] Example 1: Development of Solid Beverages 1. Carbohydrate sources 1.1 Dietary Fiber Soapberry rice, a local specialty food of Guizhou, is rich in polysaccharides and dietary fiber. The *Zhijin County Annals* records that "Soapberry granules are as thin as a fingernail, slightly white in color, and have a smooth texture. When heated in water, they expand and become translucent and gelatinous. They are fragrant, glutinous, and moist." Analysis shows that soapberry rice contains over 70% total dietary fiber, making it a high-quality source of dietary fiber. According to DBS52 *Guizhou Province Local Specialty Food Soapberry Rice*, "The recommended daily intake of soapberry rice is ≤5 g / day." Therefore, considering the product packaging, recommended intake, and dietary fiber content, the recommended serving size of soapberry rice is 12.5 servings by weight.

[0030] Table 1. Dietary fiber content of soapberry rice

[0031] 1.2 Sweeteners Glycemic carbohydrates are carbohydrates that can be digested and absorbed in the small intestine, mainly including sugars, starches (except resistant starch), and some sugar alcohols that have a glycemic effect. Therefore, the choice of sugar alcohol is crucial. Dietary energy intake is one of the important factors affecting blood sugar fluctuations. Compared with other commonly used sugar alcohols, erythritol has the characteristics of low energy coefficient, high sweetness, and low glycemic index. The energy coefficient of erythritol is 0.88 kJ / g (Table 2). Article 4 of the Q&A in the "General Rules for Nutrition Labelling of Prepackaged Foods" (GB 28050-2025) stipulates: "It is recommended that the energy coefficient of erythritol be 0 kJ / g, and the energy coefficient of other sugar alcohols be 10 kJ / g." The metabolic pathway of erythritol is not related to insulin and will not cause blood sugar fluctuations; its glycemic index is 0. Therefore, erythritol is selected as a sweetener for solid beverages.

[0032] Table 2 Commonly Used Biochemical Indicators of Sugar Alcohols

[0033] 2. Protein like Figure 1 As shown in Table 3, whey protein has a higher amino acid score and better solubility and flavor compared to soy protein isolate, casein, soy peptides, and pea protein isolate. Therefore, whey protein was chosen as the protein source. To increase the protein content of the product, whey protein 80 was selected. According to the "Dietary Guidelines for Adults with Diabetes (2023 Edition)," the recommended macronutrient ratios for diabetic patients are: 15%-20% protein and 45%-60% carbohydrates. Therefore, the whey protein addition amount is 6.25 servings (by weight percentage).

[0034] Table 3. Results of reconstitution characteristics of protein raw materials

[0035] 3 Other substances After determining the amount of saponin rice and whey protein to be added, and taking into account sensory evaluation, energy supply, carbohydrate and protein content, kudzu root powder was selected to increase product consistency, highland barley powder to increase product carbohydrate content, and apple powder to increase product sweetness.

[0036] 4 Product Formula According to the sensory evaluation criteria (Table 4), the raw materials of this product are erythritol, kudzu root powder, saponin rice powder, whey protein powder, highland barley powder, and apple powder, with weight ratios of 50%, 18.75%, 12.55%, 6.25%, 6.25%, and 6.25%, respectively.

[0037] 5. Product testing results As shown in Table 5, the product's energy, protein, available carbohydrates, and total dietary fiber are 742 kJ / 100g, 6.74 g / 100g, 29.9 g / 100g, and 11.64 g / 100g, respectively, indicating that the product is low in energy and high in dietary fiber.

[0038] Table 5 Results of Product Nutritional Component Testing

[0039] Example 2: Study on the process of making rice flour from soapberry seeds Locust bean rice is rich in dietary fiber and has a tough texture, making it difficult to grind into powder. Therefore, a process of "rehydration-crushing-freeze-drying-powdering" is used to grind locust bean rice into powder.

[0040] 1. Refill volume The water absorption of 20 g of saponin rice over time was investigated under ambient temperature and 100℃ conditions. The results show that temperature has a significant impact on the rehydration of saponin rice. After soaking for 8 hours at ambient temperature and 100℃, the water absorption was 125 g and 328 g, respectively, and the water holding capacity was 6.25 times and 16.4 times its original volume, respectively. Figure 3 Fully rehydrated saponin rice has translucent, crystalline grains and is rich in gelatinous substances. Considering the need for stirring and slight evaporation during rehydration, the amount of water added should be 20-40 times the weight of the saponin rice.

[0041] 2. Rehydration time Locust bean rice has a high water-holding capacity, and is prone to rancidity if rehydrated for too long. According to GB 2760 "National Food Safety Standard for the Use of Food Additives," sodium bicarbonate is added to shorten the rehydration time of locust bean rice. Figure 4 It can be seen that the rehydration rate of saponin rice increases after adding sodium bicarbonate. The rehydration degree at 3 hours and at 4 hours without sodium bicarbonate are compared. Considering the energy consumption of freeze-drying and sodium residue, a 5% sodium bicarbonate solution was chosen for rehydration of the saponin rice. The 5% sodium bicarbonate solution was prepared by weighing 5 g of food-grade sodium bicarbonate into a 100 mL volumetric flask and adding distilled water to the mark.

[0042] 3. Vacuum freeze drying and powdering After rehydrating with 5% sodium hydroxide solution at 100℃ for 3 hours, drain excess water and crush particles with a diameter of 3-5 mm or leave them uncrushed. Place whole saponin rice or saponin rice particles in a 40 cm × 60 cm stainless steel dish, about 1 cm thick, and perform vacuum freeze-drying with the following parameters: pre-vacuum 0.2 mbar, alarm vacuum 0.8 mbar, alarm vacuum duration 300 s. Freeze control, primary drying, and desorption drying parameters are shown in Table 6.

[0043] At the end of the experiment, both the soapberry rice and the soapberry rice particles were completely dried. The dried soapberry rice had a fluffy structure resembling white foam. After grinding, the soapberry rice slurry could be completely pulverized, but there were still unpulverized particles in the whole soapberry rice, with a diameter of 2-3 mm or even larger.

[0044] Table 6 Freeze-drying parameters

[0045] 4. Summary Soaking 1 part of saponin rice in 20-40 times its volume of 5% sodium hydroxide solution and rehydrating it at 100℃ helps shorten the rehydration time. After freeze-drying using vacuum freeze-drying technology, the resulting powder is used to prepare saponin rice powder for use in the preparation of solid beverages.

[0046] Example 3: Glycemic Index Test 1. Experimental Methods 1.1 Experimental Principle The Glycemic Index (GI) measures the effect of available carbohydrates in food on the increase in blood glucose levels in the human body. It reflects the body's blood glucose response after eating. Specifically, the GI is a quantitative indicator of the effect of carbohydrates in food on blood glucose, typically expressed as a percentage of the blood glucose response to a given mass of glucose over a specific time period, compared to a given mass of carbohydrates in a food. According to WS / T 652-2019, "Method for Determination of Glycemic Index of Foods," "If the carbohydrate content of the food being tested is low, the target amount can be appropriately reduced (e.g., 25 g or 10 g), but it must not be lower than 10 g. Once the amount of food being tested is adjusted, the reference amount must also be adjusted accordingly." Based on the GI value, foods with a GI of ≤55 are considered low-GI foods; foods with a GI of 55 < GI ≤ 70 are considered medium-GI foods; and foods with a GI of >70 are considered high-GI foods.

[0047] GL (Glycemic Load) is a measure of the combined effect of food on blood glucose by combining the glycemic index of food with the amount of available carbohydrates that can be ingested during the digestion of the food.

[0048] Based on the GL value, GL < 10 is low GL food; 10 ≤ GL ≤ 20 is medium GL food; and GL > 20 is high GL food.

[0049] 1.2 Reference Foods The reference substance used to determine the GI value of food is usually glucose. The GI value of the reference food is set at 100. In this experiment, the reference food was 250 mL of 4% anhydrous glucose solution.

[0050] 1.3 Food to be tested Based on the mass of available carbohydrates in the food to be tested (29.9 g / 100g), the amount of food to be consumed in the equivalent amount of 10 g of available carbohydrates is calculated to be 33.44 g, which is then mixed with 250 mL of drinking water at a suitable temperature and consumed.

[0051] 1.4 Blood glucose testing time.

[0052] After eating, fingertip blood was collected at 15 min, 30 min, 45 min, 60 min, 90 min, and 120 min postprandial for testing, and plotted... Figure 5 The blood glucose response curve is shown below.

[0053] 1.5 Calculation Method 1.5.1 Glycemic Index The test method follows WS / T 652-2019 "Method for Determination of Glycemic Index of Foods". The sampling method is finger-prick blood, with 2.4 μg of blood collected for each test. The glycemic index is calculated using the following formula.

[0054] ················Form (1) ······························Form (2) Where: GIn—the GI value obtained by the individual subject; IAUC – Area under the blood glucose response curve, expressed in millimoles per minute per liter (mmol·min / L). —The average of at least two reference food IAUC measurements taken from the same individual; GI – The glycemic index of the food being tested; ΣGI n —The sum of the GI values ​​derived from each individual volunteer; n — The final number of volunteers included in the calculation of the GI value of the food to be tested.

[0055] 1.5.2 Blood Glucose Load Calculation ·················Form (3) Where: GL—glucose load; GI – The GI value of the food being tested; C – The content of available carbohydrates per unit mass of food is expressed in grams (g). The food to be tested is calculated per serving (16g).

[0056] 2. Experimental Results The trial included 13 volunteers, 6 men and 7 women. Volunteer information is shown in Table 7.

[0057] Table 7 Volunteer Information Form

[0058] Three independent blood glucose measurements were performed, using two reference foods and one test food (Table 8). According to the data in Table 8, the average glycemic index of the 13 volunteers was 50, indicating that this product is a low glycemic index product.

[0059] Table 8. Average Glycemic Index

[0060] This study produced saponin rice flour using a process of "alkaline rehydration-crushing-vacuum freeze-drying-powdering". The combination of 5% NaHCO3 solution and high-temperature rehydration significantly reduced the rehydration time of saponin rice. Vacuum freeze-drying combined with the powdering process solved the problems of difficult powdering and limited downstream products. Based on the rich dietary fiber content of saponin rice, erythritol and whey protein were added to develop a low-glycemic index food product that is low in fat and energy, but high in dietary fiber and protein. Human trials showed that the product has a glycemic index below 55 and a glycemic load index below 10, classifying it as a low-glycemic index food suitable for people with high blood sugar. This product is nutritionally balanced, with moderate energy, low fat, and rich dietary fiber, exhibiting excellent health benefits. Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the technical solution of the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the content disclosed in this invention should be considered within the scope of protection of this invention.

Claims

1. A low glycemic index solid beverage, characterized in that, It is composed of the following ingredients: erythritol, kudzu root powder, saponin rice powder, whey protein powder, highland barley powder, and apple powder.

2. The low glycemic index solid beverage according to claim 1, characterized in that, It is composed of the following ingredients: 40-60 parts erythritol, 15-20 parts kudzu root powder, 10-15 parts saponin rice powder, 5-7 parts whey protein powder, 5-7 parts highland barley powder, and 5-7 parts apple powder.

3. The low glycemic index solid beverage according to claim 2, characterized in that, It is composed of the following ingredients: 50 parts erythritol, 18.75 parts kudzu root powder, 12.55 parts saponin rice powder, 6.25 parts whey protein powder, 6.25 parts highland barley powder, and 6.25 parts apple powder.

4. The low glycemic index solid beverage according to claim 1, characterized in that, The soapberry rice flour is prepared by the following method: soaking soapberry rice in 20-40 times its volume of 5% sodium hydroxide solution, rehydrating at 100°C, freeze-drying using vacuum freeze-drying technology, and then grinding into powder to obtain soapberry rice flour.

5. A method for preparing soapberry rice flour, characterized in that, The process includes the following steps: (1) Rehydration: Soaking soapberry rice in sodium hydroxide solution; (2) Crushing; (3) Freeze-drying; (4) Grinding into powder.

6. The preparation method according to claim 5, characterized in that, The rehydration process involves soaking 1 part of saponin rice in a 20-40 times sodium hydroxide solution.

7. The preparation method according to claim 5, characterized in that, The sodium hydroxide solution is a 4-6% sodium hydroxide solution.

8. The preparation method according to claim 5, characterized in that, The rehydration step (1) involves soaking 1 part of saponin rice in a 20-40 times sodium hydroxide solution.

9. The preparation method according to claim 5, characterized in that, The rehydration process (1) is carried out at a temperature of 90-100℃ for 3-4 hours.

10. The preparation method according to claim 5, characterized in that, The (2) crushing refers to draining excess water after rehydration and crushing particles with a diameter of 3-5 mm or not crushing at all.

11. The preparation method according to claim 5, characterized in that, The drying process (3) is freeze drying, which is divided into three stages: a. Pre-freezing: the pre-freezing temperature is -45 to -50℃; b. First drying: the drying temperature is -40 to 0℃; c. Second drying: the drying temperature is 10 to 50℃; the pre-freezing time is 3 to 5 hours; the first drying time is 10 to 16 hours; and the second drying time is 12 to 16 hours.

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