Sour cherry and grapefruit compound drink as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of functional food, and particularly relates to a sour cherry and grapefruit compound drink as well as a preparation method and application thereof. The sour cherry and grapefruit compound drink is prepared from the following raw materials in parts by weight: 8 to 20 parts of sour cherry concentrated juice, 4 to 10 parts of grapefruit concentrated juice, 0.5 to 2 parts of potassium citrate, 0.5 to 2 parts of sodium citrate, 0.5 to 1 part of erythritol, 0.1 to 0.2 part of mogroside, 0.003 to 0.1 part of vitamin B1, 0.003 to 0.1 part of vitamin B2 and 64.5 to 72.5 parts of water. Animal experiments show that the grapefruit extract can effectively reduce the uric acid level and protect the kidney function, and meanwhile, the effect of controlling the uric acid level can be greatly improved by combined eating of the grapefruit and the sour cherry. The sour cherry and grapefruit compound drink is used for daily control of uric acid level and regulation of body metabolism, and has a good effect.

Description

Technical Field

[0001] The invention belongs to the technical field of functional foods, and particularly relates to a sour cherry and grapefruit compound drink and a preparation method and application thereof. Background Art

[0002] High uric acid refers to a state in which the uric acid level in the blood exceeds the normal range, which may have many effects on human health. The following symptoms may occur: Gout: High uric acid may induce urate crystals to deposit in the joints, resulting in gout symptoms such as joint pain; Uric acid stones: Long-term high uric acid levels in the body cause uric acid to be unable to be excreted normally, thus forming uric acid stones in the ureter, renal pelvis and other parts; Increased nocturia: Uric acid in the body needs to be excreted with urine. If it is at a high level for a long time, it will cause increased urine, resulting in polyuria, increased nocturia and other manifestations; Gouty nephropathy: Long-term high uric acid levels may damage the glomeruli, renal tubules, etc. As the disease progresses, blood pressure will gradually increase, and even symptoms of gouty nephropathy such as low back pain may occur; Chronic hyperuricemia: Abnormal uric acid metabolism can cause patients to have chronic hyperuricemia.

[0003] High uric acid is a health problem that needs attention. Uric acid levels can be effectively controlled and the risk of related diseases can be reduced by adjusting lifestyle, drug treatment and regular monitoring. Among them, dietary adjustment is particularly important. Patients with high uric acid can assist in lowering uric acid levels through dietary adjustment. Some fruits have the effect of lowering uric acid, including cherries, watermelons, lemons, grapes, kiwis, strawberries, etc. Cherries are rich in vitamin C and antioxidants, especially anthocyanins, which help to improve the glomerular filtration of uric acid and reduce the reabsorption of uric acid by the renal tubules. Watermelon is a fruit with extremely high water content. Its water content helps to increase urine volume, thereby promoting the excretion of uric acid by diuresis. The nutrients in watermelon are relatively simple and basically do not affect uric acid metabolism. It is a more suitable fruit for people with high uric acid. Based on this, the development of a functional beverage that assists in lowering uric acid levels will have a positive impact on the daily control of uric acid levels in patients with high uric acid. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a sour cherry and grapefruit compound drink. The present invention also provides a preparation method of the sour cherry and grapefruit compound drink and an application of the sour cherry and grapefruit compound drink in a product for controlling uric acid levels.

[0005] The technical solution of the present invention is as follows: The raw materials of the sour cherry and grapefruit compound drink of the present invention include sour cherry and grapefruit.

[0006] Furthermore, the raw materials of the sour cherry and grapefruit compound drink include sour cherry concentrated juice, grapefruit concentrated juice, citrate, mogroside, vitamins and water.

[0007] The raw materials of the sour cherry and grapefruit compound drink also include erythritol.

[0008] The citrate includes potassium citrate and sodium citrate.

[0009] The vitamins include vitamin B1 and vitamin B2.

[0010] Preferably, the sour cherry and grapefruit compound drink comprises the following raw materials in parts by weight: 8-20 parts of sour cherry concentrated juice, 4-10 parts of grapefruit concentrated juice, 0.5-2 parts of potassium citrate, 0.5-2 parts of sodium citrate, 0.5-1 parts of erythritol, 0.1-0.2 parts of mogroside, 0.003-0.1 parts of vitamin B1, 0.003-0.1 parts of vitamin B2, and 64.5-72.5 parts of water.

[0011] The preparation method of the sour cherry and grapefruit compound drink of the present invention comprises the following steps: (1) Preparation of grapefruit juice concentrate: crushing fresh grapefruit whole fruit, performing ultrasonic heating, and then filtering to obtain grapefruit stock solution, and removing volatile furanocoumarin components by ohmic heating to obtain grapefruit juice concentrate; The conditions of the ohmic heating are: voltage 220V-250V, power frequency 50Hz-60Hz, heating temperature 90℃-95℃, heating time 20min-25min.

[0012] (2) Preparing sour cherry concentrated juice: crushing fresh sour cherry pulp, performing ultrasonic heating, and then filtering to obtain sour cherry concentrated juice; (3) Dissolve potassium citrate, sodium citrate, erythritol and mogroside in water to prepare liquid A, mix grapefruit juice concentrate and sour cherry juice concentrate to prepare liquid B, and dissolve vitamin B1 and vitamin B2 in water to prepare liquid C; (4) Liquid A and Liquid B are sterilized by UHT high temperature, Liquid C is sterilized by membrane filter, Liquid A, Liquid B and Liquid C are mixed and homogenized, and then filled and sealed and sterilized in a water bath to obtain the sour cherry and grapefruit compound drink; The ultrasonic heating temperature is 50-60°C.

[0013] The UHT high temperature sterilization temperature is 125°C and the time is 15s; The pore size of the membrane bacteria filter is 0.22 μm; The homogenization conditions are: temperature <40°C, low pressure 5MPa, high pressure 20MPa; The water bath sterilization temperature is 105° C. and the time is 10 min.

[0014] Application of the sour cherry and grapefruit compound drink of the present invention in preparing a product for controlling uric acid levels.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The sour cherry and grapefruit compound drink of the present invention is used for daily control of uric acid levels and regulation of body metabolism, and has a good effect. Sour cherry is a commonly consumed fruit for lowering uric acid and is widely used in uric acid lowering foods, but the uric acid lowering effect of grapefruit has not yet been discovered. The present invention finds through animal experiments that grapefruit extract can effectively reduce uric acid levels and protect kidney function. It is also found that the combined consumption of grapefruit and sour cherry can greatly increase the effect of controlling uric acid levels.

[0016] 2. Grapefruit contains furanocoumarin, which may have adverse effects on the human body, such as photosensitivity toxicity, drug interactions, etc. However, most commercially available grapefruit products use grapefruit stock solution, and rarely specifically remove the effects of this component. The present invention removes volatile furanocoumarin by ohmic heating of the grapefruit stock solution, with a removal rate of 90%. The present invention optimizes the conditions of ohmic heating, shortens the heating time, and uses short-term high temperature to volatilize most of the furanocoumarin, thereby avoiding the adverse effects of furanocoumarin on the human body, especially the effects on the metabolism of co-administered drugs.

[0017] 3. The present invention adds vitamin B1 and vitamin B2 to the sour cherry and grapefruit compound drink, which can improve the body's energy metabolism and promote the excretion of uric acid. Since vitamins B1 and B2 have poor stability in liquids and the production process requires high-temperature sterilization, the loss rate of vitamin B is high. The conventional sterilization process has a vitamin B1 loss rate of more than 70%, and a vitamin B2 loss rate of more than 20%, which is costly. The preparation method of the present invention effectively solves the problem that vitamin B is unstable in liquid and reduces the loss rate. The present invention increases the sterilization and filtration process and shortens the water bath sterilization time. The final microbial limit test of the compound drink is qualified, and the vitamin B loss is low, with a vitamin B1 loss rate of 20% and a vitamin B2 loss rate of 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a line graph showing the effect of the factor level of the ohmic heating orthogonal test on the removal rate of furanocoumarins; Figure 2 This is the heat map of the effect of the orthogonal test factor level on the stability of vitamin B and the number of microorganisms in the water bath heating process; Figure 3 This is a diagram of mouse kidney tissue morphology. DETAILED DESCRIPTION

[0019] The specific embodiments of the present invention are described in detail below in conjunction with examples. The specific embodiments described here are only for illustrating and explaining the present invention, and are not limited to the present invention. All raw materials used in the examples are commercially available unless otherwise specified.

[0020] Example 1 The sour cherry and grapefruit compound drink comprises the following raw materials in parts by weight: 15 parts of sour cherry concentrated juice, 7.5 parts of grapefruit concentrated juice, 1 part of potassium citrate, 1 part of sodium citrate, 0.5 part of erythritol, 0.1 part of mogroside, 0.05 part of vitamin B1, 0.05 part of vitamin B2, and 70 parts of water.

[0021] The preparation method of the sour cherry and grapefruit compound drink comprises the following steps: (1) Preparation of grapefruit juice concentrate: crushing fresh grapefruit whole fruit, performing ultrasonic heating, and then filtering to obtain grapefruit stock solution, and removing volatile furanocoumarin components by ohmic heating to obtain grapefruit juice concentrate; The conditions of the ohmic heating are: voltage 220V, power frequency 50Hz, heating temperature 95°C, and heating time 20min.

[0022] (2) Preparing sour cherry concentrated juice: crushing fresh sour cherry pulp, performing ultrasonic heating, and then filtering to obtain sour cherry concentrated juice; (3) Dissolve potassium citrate, sodium citrate, erythritol and mogroside in water to prepare liquid A, mix grapefruit juice concentrate and sour cherry juice concentrate to prepare liquid B, and dissolve vitamin B1 and vitamin B2 in water to prepare liquid C; (4) Liquid A and Liquid B are sterilized by UHT high temperature, Liquid C is sterilized by membrane filter, Liquid A, Liquid B and Liquid C are mixed and homogenized, and then filled and sealed and sterilized in a water bath to obtain the sour cherry and grapefruit compound drink; The ultrasonic heating temperature is 55°C; The UHT high temperature sterilization temperature is 125°C and the time is 15s; The pore size of the membrane bacteria filter is 0.22 μm; The homogenization conditions are: temperature <40°C, low pressure 5MPa, high pressure 20MPa; The water bath sterilization temperature is 105° C. and the time is 10 min.

[0023] Example 2 The sour cherry and grapefruit compound drink comprises the following raw materials in parts by weight: 8 parts of sour cherry concentrated juice, 4 parts of grapefruit concentrated juice, 0.5 parts of potassium citrate, 0.5 parts of sodium citrate, 0.5 parts of erythritol, 0.1 parts of mogroside, 0.003 parts of vitamin B1, 0.003 parts of vitamin B2, and 64.5 parts of water.

[0024] The preparation method of the sour cherry and grapefruit compound drink comprises the following steps: (1) Preparation of grapefruit juice concentrate: crushing fresh grapefruit whole fruit, performing ultrasonic heating, and then filtering to obtain grapefruit stock solution, and removing volatile furanocoumarin components by ohmic heating to obtain grapefruit juice concentrate; The conditions of the ohmic heating are: voltage 250V, power frequency 60Hz, heating temperature 90°C, and heating time 25min.

[0025] (2) Preparing sour cherry concentrated juice: crushing fresh sour cherry pulp, performing ultrasonic heating, and then filtering to obtain sour cherry concentrated juice; (3) Dissolve potassium citrate, sodium citrate, erythritol and mogroside in water to prepare liquid A, mix grapefruit juice concentrate and sour cherry juice concentrate to prepare liquid B, and dissolve vitamin B1 and vitamin B2 in water to prepare liquid C; (4) Liquid A and Liquid B are sterilized by UHT high temperature, Liquid C is sterilized by membrane filter, Liquid A, Liquid B and Liquid C are mixed and homogenized, and then filled and sealed and sterilized in a water bath to obtain the sour cherry and grapefruit compound drink; The ultrasonic heating temperature is 50°C; The UHT high temperature sterilization temperature is 125°C and the time is 15s; The pore size of the membrane bacteria filter is 0.22 μm; The homogenization conditions are: temperature <40°C, low pressure 5MPa, high pressure 20MPa; The water bath sterilization temperature is 105° C. and the time is 10 min.

[0026] Example 3 The sour cherry and grapefruit compound drink comprises the following raw materials in parts by weight: 20 parts of sour cherry concentrated juice, 10 parts of grapefruit concentrated juice, 2 parts of potassium citrate, 2 parts of sodium citrate, 1 part of erythritol, 0.2 parts of mogroside, 0.1 parts of vitamin B1, 0.1 parts of vitamin B2, and 72.5 parts of water.

[0027] The preparation method of the sour cherry and grapefruit compound drink comprises the following steps: (1) Preparation of grapefruit juice concentrate: crushing fresh grapefruit whole fruit, performing ultrasonic heating, and then filtering to obtain grapefruit stock solution, and removing volatile furanocoumarin components by ohmic heating to obtain grapefruit juice concentrate; The conditions of the ohmic heating are: voltage 220V, power frequency 50Hz, heating temperature 95°C, and heating time 20min.

[0028] (2) Preparing sour cherry concentrated juice: crushing fresh sour cherry pulp, performing ultrasonic heating, and then filtering to obtain sour cherry concentrated juice; (3) Dissolve potassium citrate, sodium citrate, erythritol and mogroside in water to prepare liquid A, mix grapefruit juice concentrate and sour cherry juice concentrate to prepare liquid B, and dissolve vitamin B1 and vitamin B2 in water to prepare liquid C; (4) Liquid A and Liquid B are sterilized by UHT high temperature, Liquid C is sterilized by membrane filter, Liquid A, Liquid B and Liquid C are mixed and homogenized, and then filled and sealed and sterilized in a water bath to obtain the sour cherry and grapefruit compound drink; The ultrasonic heating temperature is 60°C; The UHT high temperature sterilization temperature is 125°C and the time is 15s; The pore size of the membrane bacteria filter is 0.22 μm; The homogenization conditions are: temperature <40°C, low pressure 5MPa, high pressure 20MPa; The water bath sterilization temperature is 105° C. and the time is 10 min.

[0029] Experimental Example 1 In vitro XOD enzyme inhibition experiment 1. Materials and Methods Xanthine oxidase can catalyze xanthine substrate to produce uric acid, and uric acid has absorbance under 295nm ultraviolet conditions. Therefore, ultraviolet spectrophotometry can be used to indirectly measure the activity change of xanthine oxidase by measuring the change in absorbance over a certain period of time.

[0030] The experimental materials are the grapefruit juice concentrate and sour cherry juice concentrate prepared in Example 1, which are extracts of grapefruit and sour cherry.

[0031] Set up the following groups: Experimental group 1: grapefruit extract Experimental Group 2: Tart Cherry Extract Experimental group 3: sour cherry-grapefruit complex (mass ratio of sour cherry to grapefruit 1:1) Experimental group 4: sour cherry-grapefruit complex (mass ratio of sour cherry to grapefruit 1:2) Experimental group 5: sour cherry-grapefruit complex (mass ratio of sour cherry to grapefruit 2:1) Take 2mL substrate solution, 1mL phosphate buffer, 0.2mL extract, vortex mix, and finally add 0.2mL xanthine oxidase solution (0.5U / mL) pre-warmed at 25℃ for 20min to start the reaction. Record the absorbance change of the reaction system within 6min at room temperature 25℃ and UV wavelength 295nm. After completion, add 0.2mL HCl solution (1.00mol / L) to terminate the reaction. Allopurinol was used as a positive control, and the absorbance value was measured at a wavelength of 290nm. The group settings are shown in Table 1.

[0032] Table 1

[0033] Note: - means no addition, replaced with the same volume of PBS buffer.

[0034] Since xanthine has absorbance at a wavelength of 265nm, the absorbance without sample and enzyme must be deducted, and three parallel tests are performed for each sample. The calculation formula for xanthine oxidase inhibition rate is as follows:

[0035] Where A is the absorbance change of the experimental group; B is the absorbance change of the control group; C is the absorbance change of the blank control group.

[0036] 2. Experimental results The results of the XOD enzyme inhibition rates of the extracts and complexes in different proportions were obtained based on the calculations and are shown in Table 2.

[0037] Table 2

[0038] As shown in Table 2, both grapefruit extract and sour cherry extract have inhibitory effects on XOD enzyme, and the inhibition rate of grapefruit extract on XOD enzyme activity is higher than that of sour cherry extract. In the complex, when the ratio of sour cherry to grapefruit is 1:1 and 2:1, the inhibition rate of XOD enzyme activity is higher than that of the two alone, and the complex with a ratio of sour cherry to grapefruit of 2:1 shows the greatest XOD enzyme inhibition rate. 3. Conclusion Therefore, both grapefruit extract and sour cherry extract can reduce the production of uric acid by inhibiting XOD enzyme activity, and grapefruit extract showed a greater inhibitory effect. In the complex, the mass ratio of sour cherry to grapefruit of 2:1 showed the best XOD enzyme inhibition, indicating that the combined use of grapefruit and sour cherry can improve the effect of reducing uric acid.

[0039] Experimental Example 2 Animal experiment on the uric acid lowering effect of grapefruit and sour cherry extracts 1. Materials and Methods 1.1 Experimental samples: Sample 1: Grapefruit Extract Sample 2: Sour cherry grapefruit extract complex (mass ratio of sour cherry to grapefruit 2:1) 1.2 Experimental Animals: ICR male mice, weight: 180g~220g, 9 mice in total.

[0040] Animal feeding and management conditions: ambient temperature 20℃~26℃, relative humidity 40%~70%, light intensity 12h alternating between light and dark, free access to drinking water, and feeding with standard block maintenance feed.

[0041] 1.3 Reagents and instruments: 1.3.1 Main reagents: yeast extract, potassium oxonate, physiological saline, etc.

[0042] 1.3.2 Main instruments: electronic balance (MP3KC), electronic balance (ME204), fully automatic biochemical analysis analyzer (Hitachi 3100), etc.

[0043] 1.4 Test methods: 1.4.1 Modeling method Weigh 0.6g of potassium oxonate, add physiological saline to 30mL, mix thoroughly for later use; weigh 60g of yeast extract, add deionized water to 80mL, mix thoroughly for later use. Weigh the mice on the day of the experiment, give the test mice a single intraperitoneal injection of 3mL potassium oxonate, and give them 4mL yeast extract orally twice. Repeat the above process every day for 13 consecutive days, collect blood from the vein on Day 0, Day 4, Day 7, and Day 14, use an automatic biochemical analyzer to test serum uric acid levels, and weigh the mice on Day 14.

[0044] 1.4.2 Method of administration of test substance During Day 15 to Day 30, the mice in group 1 were given grapefruit extract according to their body weight, at a dose of 0.54 g / kg / day, and the mice in group 2 were given sour cherry grapefruit extract complex according to their body weight, at a dose of 0.54 g / kg / day. The control group and groups 1 and 2 were given 4 mL of yeast extract orally twice a day. The above process was repeated every day during the period, and venous blood was collected on Day 20, Day 25, and Day 30, and serum uric acid values ​​were tested using an automatic biochemical analyzer.

[0045] 2. Experimental results 2.1 Effects of the test substances on serum uric acid levels in rats The serum uric acid data at the end of the model period are shown in Table 3 , and the serum uric acid data at the end of the experiment are shown in Table 4 .

[0046] Table 3 Serum uric acid data at the end of the model period

[0047] Table 4 Serum uric acid data at the end of the trial

[0048] Note: Compared with the control group, ** indicates p≤0.01, the difference is extremely significant; * indicates p≤0.05, the difference is significant.

[0049] As shown in Table 3, there was no significant difference in the serum uric acid content of rats in each sample group compared with the control group before the administration of the test samples (P>0.05). As shown in Table 4, compared with the control group, after the experimental animals were given different test samples, the serum uric acid values ​​of the animals in the test sample 1 and sample 2 groups were reduced and the difference was extremely significant (P≤0.01); the total value of the reduction of serum uric acid in the animals in the test sample 1 and sample 2 groups was higher than that in the control group, and the difference in the sample 2 group was significant (P≤0.05), that is, when the hyperuricemia model was established, the test samples 1 and 2 could reduce the serum uric acid of SD rats, and the effect of the test sample 2 was more significant.

[0050] 3. Conclusion In this experimental example, an animal model of hyperuricemia was established. After 14 days of administration of different test samples, both test samples 1 and 2 had the effect of lowering serum uric acid, and the uric acid-lowering effect of test sample 2 (sour cherry grapefruit complex) was more significant than that of test sample 1 (grapefruit extract).

[0051] Experimental Example 3 Orthogonal test for optimizing ohmic heating conditions This experiment optimized the temperature, heating time, voltage, and power frequency. Figure 1 .

[0052] according to Figure 1 The influence trend of different factor levels on the removal rate was analyzed, and the following conclusions were obtained: (1) Temperature has a great influence on the removal rate: With the increase of temperature, the removal rate increases significantly, indicating that temperature may be a key factor affecting the removal effect of furanocoumarins. When reaching 95°C, it can meet the requirement of a removal rate of more than 90%, and can effectively control energy consumption and equipment stability.

[0053] (2) Effect of heating time: When the heating time was 20 min, the removal rate increased significantly, while it did not increase significantly when the heating time was 30 min, indicating that 20 min is an ideal time for the removal of furanocoumarins.

[0054] (3) The influence of voltage is relatively stable: between 220V and 260V, the removal rate increases less, indicating that the influence of voltage on the removal rate is relatively small. It is preferred to choose 220V with lower energy consumption to save costs.

[0055] (4) Limited influence of power frequency: The power frequency has little effect on the removal effect, and the difference between the levels is not obvious. Therefore, the standard frequency of 50 Hz can be selected to meet the standard requirements of the production process.

[0056] In summary, the optimal parameters for ohmic heating are: temperature 95°C, time 20min, voltage 220V, and power frequency 50Hz. Under these conditions, the removal of furanocoumarins is best while taking energy consumption into consideration.

[0057] Experimental Example 4 Orthogonal test for optimizing water bath heating process conditions This experimental example uses a water bath sterilization orthogonal test to obtain Figure 2 The comprehensive heat map shown in the figure shows the vitamin B1 loss rate, vitamin B2 loss rate and microbial count (CFU / mL) under different temperature and time combinations. Figure 2 It can be seen that: (1) Vitamin B1 loss: The loss rate of vitamin B1 increases significantly with the increase of temperature and time, especially at the combination of 110°C and a longer time, where the loss is greatest.

[0058] (2) Vitamin B2 loss: The loss rate of vitamin B2 increases with time and temperature in a similar manner to that of vitamin B1, but the loss is smaller than that of B1.

[0059] (3) Microbial count: 105°C for 10 min can reduce the number of microorganisms to 20 CFU / mL, and the nutrient loss is relatively small, which is the best parameter combination. The higher the temperature and time, the more obvious the reduction in the number of microorganisms, and above 105°C, effective sterilization is almost achieved.

[0060] Based on the above analysis, 105°C for 10 min is a balanced time-temperature combination, which can effectively reduce the number of microorganisms and reduce the loss of vitamins.

[0061] Experimental Example 5 Animal experiment on the effect of sour cherry and grapefruit compound drink on lowering uric acid 1. Materials and Methods 1.1 Experimental sample: the sour cherry and grapefruit compound drink prepared in Example 1.

[0062] 1.2 Experimental Animals: ICR male mice, weight: 180g~220g, 9 mice in total.

[0063] Animal feeding and management conditions: ambient temperature 20℃~26℃, relative humidity 40%~70%, light intensity 12h alternating between light and dark, free access to drinking water, and feeding with standard block maintenance feed.

[0064] 1.3 Reagents and instruments: 1.3.1 Main reagents: yeast extract, potassium oxonate, physiological saline, etc.

[0065] 1.3.2 Main instruments: electronic balance (MP3KC), electronic balance (ME204), serum uric acid test kit, pH test paper, etc.

[0066] 1.4 Test methods: 1.4.1 Modeling method Weigh 0.6g of potassium oxonate, add physiological saline to 30mL, mix thoroughly for later use; weigh 60g of yeast extract, add deionized water to 80mL, mix thoroughly for later use. Weigh on the day of the experiment, give the test mice a single intraperitoneal injection of 3mL potassium oxonate, and give them 4mL yeast extract orally twice. Repeat the above process every day for 20 consecutive days, observe the animal status every day, and collect blood from the vein on Day 0 and Day 20 for serum uric acid test.

[0067] 1.4.2 Method of administering the test substance Weighing was performed on Day 21. From Day 21 to Day 28, mice in the experimental group were given a sour cherry-grapefruit compound drink according to body weight, at a dose of 13.5 g / kg / d. The model group, positive control group, and experimental group were given 4 mL of yeast extract orally twice a day. The positive control group was given allopurinol according to body weight, at a dose of 10 mg / kg / d. The blank group was gavaged with an equal amount of water. The above process was repeated every day during the period, and the animal status was observed. The urine was collected on Day 28 and then the animals were killed. Blood and kidney tissue were collected for serum uric acid detection, urine pH was measured, and differences in the appearance of kidney tissue were observed.

[0068] 2. Results 2.1 Effects of the test substances on the pH value of mouse urine The pH values ​​of mouse urine after administration of the test substance are shown in Table 5. It can be seen that compared with the blank group, the pH of urine in the model group decreased, the pH difference of the positive control was small, and the pH of urine in the experimental group increased.

[0069] Table 5

[0070] 2.2 Effects of the test substances on serum uric acid levels in mice The serum uric acid levels of mice after administration of the test substance are shown in Table 6. It can be seen that compared with the blank group, the serum uric acid in the model group increased by 339.47%; compared with the model group, the serum uric acid in the positive control group decreased by 51.06%, and the experimental group decreased by 47.19%. Table 6 Serum uric acid values

[0071] 2.3 Effects of the test substance on mouse kidney tissue Changes in the kidney tissue of mice after administration of the test substance, such as Figure 3. The surface capsule of the kidney tissue in the blank group was composed of dense connective tissue of uniform thickness; the renal parenchyma was composed of the superficial cortex and deep medulla, with a clear boundary between the cortex and medulla; the glomeruli were evenly distributed in the cortex, the number of cells and matrix in the glomeruli were uniform, the renal tubular epithelial cells were round and plump, the brush borders were arranged neatly and regularly, and no obvious abnormalities were found in the medulla. In the renal tissue of the model group, extensive irregular arrangement of renal tubules, narrow and enlarged tubular lumens, vacuolation of some renal tubular epithelial cells, detachment of the internal brush borders, inflammatory cell infiltration around the renal tubules, obvious atrophy of the glomeruli, and a decrease in the number of internal cells were observed.

[0072] The degree of renal pathological tissue damage in the test group mice was significantly reduced, the morphology of renal tubules in the experimental group was significantly improved, the glomeruli were plump, the number of internal cells and the matrix were plump and uniform, close to the blank group, the renal damage in the allopurinol group was more obvious, the renal tubules were irregularly arranged, the lumen was narrow and enlarged, the glomeruli were atrophied, the number of internal cells and the matrix decreased, and renal structural lesions occurred, indicating that the test substance can improve the damage of uric acid to the mouse kidneys, and allopurinol has certain renal toxicity.

[0073] 3. Conclusion The animal experiment concluded that after the uric acid level of mice increased, the urine pH decreased and the urine became acidic. After using allopurinol, the urine pH value tended to normal. After consuming the sour cherry grapefruit compound drink, the urine pH increased and the urine became alkaline, indicating that it had the effect of alkalizing urine; compared with the model group, the blood uric acid level in the positive control group decreased by 51.06%, and the experimental group decreased by 47.19%, indicating that allopurinol and the sour cherry grapefruit compound drink both had the effect of lowering uric acid. According to the kidney stained pathological sections, the experimental group had an improvement effect on the morphological structure of kidney tissue, and the allopurinol group had kidney structural lesions and damage, indicating that allopurinol had a certain renal toxicity. Therefore, the results of this experiment showed that the sour cherry grapefruit compound drink had a good effect of lowering blood uric acid. One of the mechanisms was to alkalize urine and promote the excretion of uric acid. At the same time, the sour cherry grapefruit compound drink could improve kidney damage caused by high uric acid, and its effectiveness and safety were verified.

Claims

1. A sour cherry and grapefruit compound drink, characterized in that: Its ingredients include sour cherry and grapefruit.

2. The sour cherry and grapefruit compound drink according to claim 1, characterized in that: Its ingredients include sour cherry juice concentrate, grapefruit juice concentrate, citrate, mogroside, vitamins and water.

3. The sour cherry and grapefruit compound drink according to claim 2, characterized in that: Its raw materials also include erythritol.

4. The sour cherry and grapefruit compound drink according to claim 3, characterized in that: The citrate includes potassium citrate and sodium citrate.

5. The sour cherry and grapefruit compound drink according to claim 4, characterized in that: The vitamins include vitamin B1 and vitamin B2.

6. The sour cherry and grapefruit compound drink according to claim 5, characterized in that: The invention comprises the following raw materials in parts by weight: 8-20 parts of sour cherry concentrated juice, 4-10 parts of grapefruit concentrated juice, 0.5-2 parts of potassium citrate, 0.5-2 parts of sodium citrate, 0.5-1 parts of erythritol, 0.1-0.2 parts of mogroside, 0.003-0.1 parts of vitamin B1, 0.003-0.1 parts of vitamin B2 and 64.5-72.5 parts of water.

7. The method for preparing the sour cherry and grapefruit compound drink according to claim 6, characterized in that: The following steps are involved: (1) Preparation of grapefruit juice concentrate: crushing fresh grapefruit whole fruit, performing ultrasonic heating, and then filtering to obtain grapefruit stock solution, and removing volatile furanocoumarin components by ohmic heating to obtain grapefruit juice concentrate; (2) Preparing sour cherry concentrated juice: crushing fresh sour cherry pulp, performing ultrasonic heating, and then filtering to obtain sour cherry concentrated juice; (3) Dissolve potassium citrate, sodium citrate, erythritol and mogroside in water to prepare liquid A, mix grapefruit juice concentrate and sour cherry juice concentrate to prepare liquid B, and dissolve vitamin B1 and vitamin B2 in water to prepare liquid C; (4) Liquid A and Liquid B are sterilized by UHT high temperature, and Liquid C is sterilized by membrane filter. Liquid A, Liquid B and Liquid C are mixed and homogenized, and then filled and sealed and sterilized in a water bath to obtain the sour cherry grapefruit compound drink.

8. The method for preparing the sour cherry and grapefruit compound drink according to claim 7, characterized in that: The conditions of the ohmic heating are: voltage 220V-250V, heating temperature 90°C-95°C, and heating time 20min-25min.

9. The method for preparing the sour cherry and grapefruit compound drink according to claim 7, characterized in that: The water bath sterilization temperature is 105° C. and the time is 10 min.

10. Use of the sour cherry and grapefruit compound drink according to claim 1 in preparing a product for controlling uric acid levels.

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