A method for preparing a high-pressure homogenization method of gong orange juice

Abstract

The application belongs to the technical field of deep processing of Citrus grandis, and particularly relates to a method for preparing Citrus grandis turbid juice by high-pressure homogenization. The method for preparing Citrus grandis turbid juice by high-pressure homogenization provided by the application is to prepare Citrus grandis turbid juice by high-pressure homogenization treatment of Citrus grandis turbid liquid, and the influence of homogenization pressure and times on the turbidity, centrifugal precipitation rate, laser particle size and other stability indexes of the Citrus grandis turbid juice and the influence of homogenization pressure and times on pH, total soluble solids, total acid, solid acid ratio, reducing sugar content, color, total phenol content and vitamin C content and other quality indexes are explored. The application specifically analyzes the stability of the Citrus grandis turbid juice induced by high-pressure homogenization and the changes of the physicochemical and quality indexes of the turbid juice, and lays a foundation for subsequent research on the influence mechanism of high-pressure homogenization on the stability and quality of the Citrus grandis turbid juice.

Description

Technical Field

[0001] This invention belongs to the field of deep processing technology of Gonggan oranges, specifically relating to a method for preparing Gonggan orange cloudy juice by high-pressure homogenization. Background Technology

[0002] Gonggan ( Citrus sinensis Osb.'Deqing Gonggan' This variety is a natural hybrid of orange and mandarin orange, possessing characteristics of both. Deqing Gonggan is a traditional and high-quality agricultural product of Deqing County, with a long history of cultivation. Its beautiful shape, golden color, thin peel, few seeds, high sugar content, and low acidity have earned it the title of "King of Citrus Fruits." Gonggan is primarily consumed fresh, resulting in a short shelf life. Whole-fruit juicing of Gonggan involves pressing the entire fruit into juice, then processing the pulp and peel using colloid mills or other micro-grinding equipment to pulverize, disperse, homogenize, and emulsify them, resulting in a cloudy juice product. Whole-fruit juicing retains pectin, polyphenols, and other active substances, transforming the resource advantages of Gonggan into product advantages.

[0003] Patent document CN112841468A discloses a mandarin orange juice beverage and its preparation method. The raw materials of the mandarin orange juice beverage include concentrated mandarin orange juice, white sugar, high-fructose corn syrup, a sweetener, acidity regulator I, acidity regulator II, an antioxidant, a thickener, food coloring, a preservative, edible flavoring, and water. The preparation method is as follows: the concentrated mandarin orange juice, white sugar, high-fructose corn syrup, sweetener, acidity regulator I, acidity regulator II, and antioxidant are dissolved in water; the thickener, food coloring, and preservative are dissolved separately in water; all raw materials are mixed evenly, then bottled, sterilized, and cooled to room temperature to obtain the mandarin orange juice beverage. The mandarin orange juice beverage provided by this invention has a good mandarin orange flavor, is sweet and sour, and is suitable for drinking.

[0004] Patent document CN120345665A discloses a whole-fruit juice beverage made from Gonggan tangerines and its preparation method. This Gonggan whole-fruit juice beverage utilizes technologies such as juice micro-processing combined with high-efficiency catalysis of compound enzymes. After whole-fruit juicing of Gonggan tangerines, the pulp and peel are subjected to wet ultra-micro pulverization, effectively pulverizing, dispersing, homogenizing, emulsifying, and sterilizing them. Then, compound enzymes are added for enzymatic hydrolysis, followed by debittering and sterilization, yielding the final product. The resulting whole-fruit juice beverage possesses a rich Gonggan tangerine flavor, moderate viscosity, and a rich taste. Furthermore, it is rich in nutrients and highly stable, providing a theoretical basis for developing high-quality whole-fruit juice products made from Gonggan tangerines.

[0005] However, during the whole-fruit juice extraction process of Gonggan tangerines, the peel cells rupture, and membranes and many components, such as pectin, protein, cellulose, hemicellulose, and hesperidin, become suspended in the juice, affecting its stability. Furthermore, the presence of pectin and pectin methylesterase (PME) easily leads to stratification and precipitation, severely impacting consumer acceptance and the product's market value. Therefore, improving the stability, nutritional value, and functional quality of Gonggan whole-fruit juice is a crucial technical challenge that urgently needs to be addressed during processing, storage, and sales.

[0006] High-pressure homogenization (HPH) is an emerging non-thermal processing method commonly used in fruit and vegetable juice processing. During HPH treatment, the juice is subjected to high pressure and high speed through a narrow, adjustable gap in a homogenizing valve. This generates pressure gradients, shear forces, high-speed collisions, and cavitation effects, causing polymers, particles, or cells in the system to break down and release bioactive substances, thereby improving the stability, nutritional value, and functional properties of the juice. Currently, there is no comprehensive study on the stability and quality of cloudy Gonggan juice after HPH treatment. Therefore, researching and exploring the mechanism by which HPH treatment affects the stability and quality of cloudy Gonggan juice will contribute to the promotion and application of high-pressure homogenization in the deep processing of Gonggan oranges. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for preparing cloudy juice of Gonggan oranges using high-pressure homogenization. This invention aims to provide a comprehensive analysis and evaluation of the stability, physicochemical properties, and nutritional quality of cloudy juice of Gonggan oranges after treatment with different homogenization pressures and cycles. Specifically, high-pressure homogenization was used to treat the cloudy juice of Gonggan oranges, and the effects of homogenization pressure (200-600 bar) and the number of homogenization cycles (1-3 times) on stability indicators such as turbidity, centrifugal sedimentation rate, and laser particle size, as well as quality indicators such as pH, TSS (Total Soluble Solids), total acid (TA), solid-acid ratio, reducing sugar content, color, total phenol content, and vitamin C content were investigated. The stability and changes in physicochemical and quality indicators of the cloudy juice induced by high-pressure homogenization were specifically analyzed, providing a reference for the industrial production of cloudy juice of Gonggan oranges using high-pressure homogenization.

[0008] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing tangerine juice using high-pressure homogenization, comprising the following steps: Step S1: Wash the ripe tangerines, cut them in half, remove the seeds, and then put them into a blender and blend for 4-6 minutes to obtain a tangerine suspension. Step S2: Add the Gonggan suspension obtained in step S1 to distilled water, then stir with a colloid mill for 2-4 minutes, filter, and obtain Gonggan turbid liquid. Step S3: The turbid liquid of tangerines obtained in step S2 is subjected to high-pressure homogenization and sterilization to obtain the final product.

[0009] Furthermore, in step S2, the mass ratio of the mandarin orange suspension to distilled water is 1:4, that is, 20% (mass percentage) of the mandarin orange suspension is added to 80% (mass percentage) of the distilled water.

[0010] Furthermore, the conditions for high-pressure homogenization in step S3 are: treatment 1 to 3 times at 200 to 600 bar.

[0011] Furthermore, step S3, after sterilization, also includes fermentation treatment, specifically as follows: inoculating the sterilized Gonggan turbid juice with brewer's yeast culture, introducing oxygen, and fermenting at a temperature of 28~33 ℃ for 12~24 h, then inoculating with Lactobacillus plantarum culture, introducing oxygen for 1~3 h, sealing, and fermenting at a temperature of 35~37 ℃ for 12~24 h, centrifuging, taking the supernatant to obtain Gonggan fermented product, freeze-drying to obtain Gonggan fermented powder.

[0012] Furthermore, the inoculation amount of the brewer's yeast solution is 4-6% of the total volume of the Gonggan orange juice, and the viable count of the brewer's yeast solution is 1×10⁻⁶. 10 ~1×10 12 cfu / mL.

[0013] Furthermore, the inoculation amount of the *Lactobacillus plantarum* bacterial solution is 3-6% of the total volume of the tangerine juice, and the viable count of the *Lactobacillus plantarum* bacterial solution is 2.5 × 10⁻⁶. 9 ~2.5×10 11 cfu / mL.

[0014] In addition, the present invention also provides a composition comprising the following components and their weight proportions: 10-16 parts of tangerine fermentation powder, 8-12 parts of dried plum extract, and 6-8 parts of licorice extract.

[0015] Furthermore, the preparation method of the plum extract is as follows: Take dried plums, crush them to obtain plum powder, add the plum powder to an ethanol solution with a volume concentration of 65-75%, and reflux extract 2-3 times at a temperature of 65-75 ℃, each time for 1-2 hours. Combine the extracts, filter, concentrate, and freeze dry to obtain the final product.

[0016] Furthermore, the ratio of the dried plum powder to the ethanol solution is 1g:6~8mL.

[0017] Furthermore, the method for preparing the licorice extract is as follows: Take dried licorice root, wash it clean, crush it to obtain licorice powder, add distilled water, the ratio of licorice powder to distilled water is 1 g: 15~20 mL, sonicate at 45~55 ℃ for 40~60 min, the sonication power is 200~300 W, filter, concentrate, freeze dry to obtain licorice extract.

[0018] This invention primarily investigates the effects of HPH (high-pressure homogenization) on the stability, physiological, and nutritional quality of Gonggan cloudy juice. Results show that HPH treatment improves the symmetry of particle size distribution in Gonggan cloudy juice, increasing particle diameter. Simultaneously, HPH treatment affects particle stability in the Gonggan cloudy juice system and may influence turbidity by affecting the binding of proteins, pectin, and small particles, thus improving the dispersibility and stability of the cloudy juice system to some extent. Furthermore, HPH treatment increases the brightness of Gonggan cloudy juice, making its color appear relatively greener and yellower. While TSS, TA, and the solid-acid ratio show no significant changes, the vitamin C content decreases significantly. HPH treatment also inhibits PME cleavage of pectin, increases total phenol content, and decreases soluble protein content. This fully demonstrates that HPH not only improves the symmetry of particle size distribution in Gonggan cloudy juice and enhances its dispersibility and stability, but also effectively improves its sensory and nutritional quality, promoting the development of HPH in the processing of Gonggan cloudy juice and other fruit juices.

[0019] Furthermore, the inventors discovered during their research that the Gonggan orange juice prepared by high-pressure homogenization, and the resulting Gonggan orange fermented powder obtained by adding yeast and plant lactic acid bacteria, has a health-promoting effect on improving blood sugar. In particular, when this Gonggan orange fermented powder is used in combination with plum extract and licorice extract, the three interact synergistically to enhance the blood sugar-lowering effect, effectively broadening the application areas of Gonggan orange fermented products.

[0020] In summary, compared with the prior art, the high-pressure homogenization method for preparing tangerine juice provided by the present invention has the following advantages: (1) The high-pressure homogenization method used in this invention to prepare the Gonggan cloudy juice system has the advantages of good dispersibility, high stability and high nutritional quality, indicating that the high-pressure homogenization method has potential application prospects in the processing of Gonggan cloudy juice and other juices.

[0021] (2) The present invention uses high pressure homogenization to prepare Gonggan turbid juice, and then adds yeast and plant lactic acid bacteria to ferment Gonggan fermented powder, which has the health care effect of improving blood sugar and can effectively broaden the application field of Gonggan fermented products. Attached Figure Description

[0022] Figure 1The figure shows the effect of different high-pressure homogenization treatments on the turbidity and centrifugal sedimentation rate of Gonggan juice.

[0023] Figure 2 The figure shows the effect of different high-pressure homogenization treatments on the rheological properties of Gonggan orange juice.

[0024] Figure 3 The graph shows the changes in soluble protein and total phenol content in the cloudy juice of Gonggan oranges after different high-pressure homogenization treatments.

[0025] Figure 4 The graph shows the changes in total pectin content and pectin lyase activity in the cloudy juice of Gonggan oranges after different high-pressure homogenization treatments. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Experiment 1: An exploratory experiment to optimize the stability and nutritional quality of Gonggan orange juice using high-pressure homogenization. 1. Experimental Method: 1.1 Preparation of Gonggan Orange Juice: (1) Using Deqing Gonggan (produced in Deqing County, Guangdong Province), select mature Gonggan that are uniform in size, free from pests and diseases and mechanical damage, wash them with running water, cut them in half, remove the seeds, and then put them into a mixer and stir for 5 minutes to obtain Gonggan suspension. (2) Add the 20% (mass percentage) Gonggan suspension to 80% (mass percentage) distilled water, then stir with a colloid mill for 3 min, and filter with a 100-mesh filter to obtain Gonggan turbid liquid; (3) The prepared turbid Gonggan juice was homogenized at 200, 400, and 600 bar for 1 to 3 times (named as 200-1, 200-2, 200-3, 400-1, 400-2, 400-3, 600-1, 600-2, and 600-3 groups, respectively). The stability and changes in quality indicators of the turbid Gonggan juice were measured by comparing it with ordinary homogenization for 1 to 3 times (0-1, 0-2, 0-3) and untreated turbid Gonggan juice (NH group). Each treatment was repeated 3 times. Before homogenization, the high-pressure homogenizer was sterilized with 95% ethanol to reduce microorganisms.

[0028] 1.2 Determination of stability index of Gonggan orange turbid juice: 1.2.1 Determination of particle size distribution of turbid juice from Gonggan oranges: The particle-size distribution (PSD) was determined using a Mastersizer 2000 (Malvern Instruments, Malvern, UK). This instrument calculated the average volume-weighted diameter (D[4,3], μm), the surface-weighted average diameter (D[3,2], μm), and the diameters corresponding to 90% of the particle volume (D90, μm), 50% of the particle volume (D50, μm), and 10% of the particle volume (D10, μm). The relative width of the particle distribution spectrum (i.e., "dispersion") was calculated using the following formula: 1.2.2. Turbidity determination of tangerine juice: Centrifuge 10 mL of turbid orange juice at 4000 r / min for 15 min, use distilled water as a blank, and measure the absorbance of the supernatant at a wavelength of 660 nm. Turbidity is expressed as absorbance value. Repeat the test 3 times.

[0029] 1.2.3 Determination of centrifugal sedimentation rate of turbid juice from Gonggan oranges: Weigh 10 g of the cloudy juice sample from Gonggan oranges, centrifuge at 4000 r / min for 20 min, discard the supernatant, and dry the centrifuge tube in a 40℃ oven for 24 h. Repeat the test three times. The formula for calculating the centrifugation sedimentation rate is: W represents the weight of the precipitate after drying.

[0030] 1.3 Determination of the rheological properties of Gonggan orange turbid juice: The viscosity of the cloudy orange juice sample was measured using a rheometer (Physica MCR 301; Anton Paar, Graz, Austria) equipped with parallel plates of 50 mm diameter and a gap of 1 mm. The temperature was kept constant at 25 °C. In steady-state shear mode, the cloudy juice sample (2.3 mL) was placed between the two plates, and the viscosity was measured at 0.1 s⁻¹. -1 up to 100 s -1 The change in shear stress was measured within the range of shear rates.

[0031] 1.4 Determination of quality indicators for Gonggan orange juice: 1.4.1 Determination of the color of cloudy tangerine juice: The color of the cloudy juice of Konica Minolta was measured using a CR400 chromameter (Konica Minolta Inc., Osaka, Japan). After calibration with a white and black board, the color of the samples was measured, and the values ​​of L*, a*, and b* were recorded. The test was repeated 6 times, and the total color difference (ΔE) was calculated using the following formula.

[0032] Where L0*, a0*, and b0* are the control color values ​​of the untreated juice, respectively.

[0033] 1.4.2 Determination of TSS (Total Soluble Solids), Total Acid (TA), Solid-Acid Ratio, Reducing Sugar, and Total Sugar in Gonggan Orange Juice: The TSS content of the samples was determined using a digital saccharimeter, and the TSS content was expressed as °Brix. The TA content was determined using the acid-base indicator titration method (GB 12456-2021), and the TA content was expressed as a percentage. The sugar-acid ratio (TSS / TA) was calculated. The tests were repeated three times. The reducing sugar and total sugar content in the cloudy juice of Gonggan oranges was determined using the 3,5-dinitrosalicylic acid method, and the tests were repeated three times.

[0034] 1.4.3 Determination of total phenols, vitamin C, and soluble protein content in Gonggan orange juice: The total phenol content of Gonggan orange juice was determined using the Folin-Ciocalteu method. Using 60% ethanol as a blank, the absorbance at 765 nm was measured. The results are expressed as gallic acid equivalents (μg / g) per g of Gonggan orange juice. The vitamin C content in the juice was determined spectrophotometrically. 0.5 mL of the sample was mixed with 5 mL of 50 g / L trichloroacetic acid solution, and the volume was adjusted to 100 mL with 50 g / L trichloroacetic acid solution. After extraction and centrifugation, 1 mL of the supernatant was collected, and 1 mL each of 50 g / L trichloroacetic acid solution and anhydrous ethanol were added and mixed thoroughly. Subsequently, 0.5 mL of 0.4% phosphoric acid-ethanol solution, 1 mL of 5 g / L phenanthroline-ethanol solution, and 0.5 mL of 0.3 g / L FeCl3-ethanol solution were added sequentially. The reaction was carried out at 30 ℃ for 60 min, and the absorbance was measured at 534 nm. The vitamin C content in the sample was calculated by comparing with the corresponding vitamin C standard curve, and the results are expressed as mg / mL. The soluble protein content in the cloudy juice of Gonggan oranges was determined using the Coomassie brilliant blue method, and the absorbance at 595 nm was measured. All tests were repeated three times.

[0035] 1.5 Determination of soluble pectin content and pectin methyl esterase activity in Gonggan orange juice: 1.5.1 Determination of soluble pectin content in Gonggan orange juice: The soluble pectin content of Gonggan orange cloudy juice was determined using the carbazole colorimetric method, following the kit instructions. Results are expressed as μg galacturonic acid equivalents (μg / mL) per milliliter of Gonggan orange cloudy juice. The test was repeated three times.

[0036] 1.5.2 Determination of pectin methyl esterase activity in Gonggan orange juice: The PME activity of turbid Gonggan juice was determined by potentiometric titration. 40 mL of 1% pectin solution (containing 0.1 mol / L NaCl, pH 7.5) was incubated in a 30 °C water bath. 5 mL of turbid Gonggan juice (pH adjusted to 7.5 with NaOH) was added, and the mixture was thoroughly mixed while timing was started. An automatic titrator was used to automatically adjust the pH of the mixture to 7.5 by adding 0.01 mol / L NaOH solution. The amount of NaOH solution consumed in each titration over 10 min was recorded. The test was repeated three times. One unit of enzyme activity (U) was defined as the amount of μmol NaOH equivalent consumed per mL of sample per min. The relative PME activity was calculated using the PME activity in the blank control group as a reference.

[0037] 2. Experimental Results: 2.1 Results of stability index testing for Gonggan orange juice: 2.1.1 The particle size distribution of the turbid juice of Gonggan oranges is shown in Table 1: Table 1. Particle size distribution of turbid juice from Gonggan oranges treated with different pH values. Where: D[4,3]: volume (weight) weighted average particle size; D[3,2]: area weighted average particle size; D50: represents the cumulative value under the particle size volume distribution, indicating that particles smaller than this particle size account for 50% of the total sample volume.

[0038] Table 1 shows that the NH group had uneven color and visible Gonggan tangerine particles precipitated, which is consistent with the experimental results. The D[4,3] and D50 values ​​in the non-homogenized sample differed by a factor of 7. Compared with other HPH groups, the 200-2 and 400-2 treatment groups had smaller Gonggan tangerine juice particles, and the D50 and D[4,3] values ​​were similar, with a more symmetrical particle size distribution, consistent with experimental observations. Compared with the NH group, HPH significantly increased the D[4,3], D[3,2], and D50 values ​​in the turbid juice sample. The HPH process had a similar effect on both large and small particles. The increased particle size after homogenization indicates that HPH treatment can improve the state of Gonggan tangerine turbid juice, manifested as increased particle size, varying degrees of aggregation of large and small particles, and increased symmetry in particle size distribution. In addition, homogenization significantly enhanced the symmetry of particle size distribution in the turbid juice system. Under the same homogenization pressure, the particle size in the cloudy juice did not decrease with the increase of homogenization times, but always reached its minimum value during the second homogenization. Furthermore, the changes in D[3,2] and D[4,3] were relatively synchronous, indicating that the particle size aggregation of the Gonggan cloudy juice was smaller under different pressures during secondary homogenization, which was more conducive to the homogenization of particles in the Gonggan cloudy juice. Other homogenization treatments resulted in a larger particle aggregation in the Gonggan cloudy juice, which might affect the stability of the Gonggan cloudy juice system while achieving uniform particle size. The degree of aggregation of the cloudy juice varied under different HPH pressures and homogenization times. The D50 of well-prepared Gonggan cloudy juice was 41.38 and 65.27.

[0039] 2.1.2 Results of the determination of turbidity and centrifugal sedimentation rate of Gonggan orange juice: The results of the determination of turbidity and centrifugal sedimentation rate of Gonggan orange juice are as follows: Figure 1 As shown. Figure 1 The figure shows the effect of different high-pressure homogenization treatments on the turbidity and centrifugal sedimentation rate of Gonggan juice.

[0040] Turbidity is an important indicator of the suspension stability of fresh fruit juice; higher turbidity indicates better stability. Figure 1 It can be seen that compared with the unhomogenized turbid juice of Gonggan oranges, the difference in turbidity after ordinary homogenization was not significant. However, the turbidity decreased by an average of 23.20% after high-pressure homogenization, and the turbidity at 600 MPa pressure was 32.60% of that of the control group. Centrifugation sedimentation rate is an important parameter reflecting the stability of turbid juice; the lower the value, the higher the stability, and vice versa. Figure 1 It can be seen that ordinary homogenization has no significant effect on the centrifugal sedimentation rate of Gonggan turbid juice (P>0.05), while the centrifugal sedimentation rate decreased by 26.43% after high-pressure homogenization. Among them, when the homogenization pressure reached 400 MPa, the sedimentation rate was the lowest after three homogenizations, which was only 56.53% of the control group.

[0041] 2.2 Results of Rheological Properties Measurement of Gonggan Orange Turbid Juice: The results of the variable properties determination of the turbid juice flow of Gonggan oranges are as follows: Figure 2 As shown. Figure 2 The figure shows the effect of different high-pressure homogenization treatments on the rheological properties of Gonggan orange juice. Among them: Figure 2 (a) is the apparent viscosity of the turbid juice of Gonggan oranges. Figure 2 (b) is the shear stress of the turbid juice of the mandarin orange.

[0042] Between 0.1 and 100 s -1 The viscosity of the mandarin orange juice was measured within the range of shear rates. Figure 2 (a) It can be seen that the HPH-treated cloudy juice of Gonggan oranges conforms to the shear-thinning model, among which: treatments of 400-1, 600-1, 400-2, and 200-3 resulted in a significant increase in the viscosity of the cloudy juice. Figure 2 (b) It can be seen that the shear stress increases rapidly with the increase of the shear rate, and then tends to level off. Among them, the treatments of 400-1, 600-1, 400-2, and 200-3 resulted in a significant increase in shear stress, possibly because the interaction between the solute and particles in the Gonggan juice system generates entanglement, thus providing greater resistance to the flow of the suspension.

[0043] 2.3 Determination of Quality Indicators of Gonggan Orange Turbid Juice: 2.3.1 The color determination results of the cloudy juice of Gonggan oranges are shown in Table 2: Table 2. Effects of different high-pressure homogenization treatments on the color of Gonggan orange turbid juice. Color is an important indicator of fruit juice and is related to its freshness. Table 2 shows that homogenization significantly improves the brightness of cloudy juice. The L* value of cloudy Gonggan juice increased significantly after both ordinary and high-pressure homogenization, and was significantly higher than that of the NH group ( P<0.05 However, the changes between different homogenization pressures and cycles were not significant. The a* value gradually decreased with increasing homogenization pressure and cycles, indicating that high-pressure homogenization caused the cloudy juice to turn greenish. An increase in the b* value indicated that the cloudy juice turned yellow, and the degree of yellowing of the Gonggan cloudy juice decreased with increasing high-pressure homogenization pressure and cycles. This shows that after high-pressure homogenization, the brightness of the Gonggan cloudy juice increased, and the color became relatively greener and yellower, and these changes were all obvious color differences, most of which were visible to the naked eye.

[0044] 2.3.2 Results of TSS, total acid, glutamate-to-acid ratio, reducing sugar, and total sugar determination of Gonggan orange juice: The results of TSS, total acid, glutamate-to-acid ratio, reducing sugar, and total sugar determination of Gonggan cloudy juice are shown in Table 3. Table 3. Effects of different high-pressure homogenization treatments on TSS, TA, soluble acid ratio and reducing sugar content of Gonggan orange juice. Table 3 shows that, compared with the unhomogenized sample, the TSS, TA, and saturated acid ratio of Gonggan cloudy juice did not change significantly after high-pressure homogenization. Furthermore, different homogenization pressures and cycles had no significant effect on the TA, saturated acid ratio, or reducing sugar content of Gonggan cloudy juice. However, high-pressure homogenization significantly reduced the vitamin C content in Gonggan cloudy juice. P<0.05 Under homogenization pressures of 0, 400, and 600 bar, the vitamin C content of the turbid juice increased significantly with the number of homogenization cycles, but was still much lower than that of the NH group.

[0045] 2.3.3 Results of determination of total phenols and soluble protein content in Gonggan orange juice: The results of the determination of total phenols and soluble protein content in Gonggan orange juice are as follows: Figure 3 As shown. Figure 3 The graph shows the changes in soluble protein and total phenol content in Gonggan orange juice after different high-pressure homogenization treatments. (The graph includes the following information:) Figure 3 (a) shows the change in soluble protein content. Figure 3 (b) shows the change in total phenol content.

[0046] Depend on Figure 3 (a) It is known that ordinary homogenization increases the soluble protein content in the cloudy juice of Gonggan oranges, while high-pressure homogenization reduces the soluble protein content in the cloudy juice by an average of 45.48%, and the soluble protein content decreases in a gradient manner with increasing homogenization pressure and number of homogenization cycles. Therefore, for the Gonggan cloudy juice system, high-pressure homogenization may affect the activity of enzymes in the Gonggan cloudy juice while destroying the cell wall, changing the protein structure, and the binding of proteins with small particulate matter in the cloudy juice system, resulting in a decrease in protein solubility in the cloudy juice, and the degree is related to HPH pressure and number of homogenization cycles.

[0047] Depend on Figure 3 (b) It can be seen that ordinary homogenization leads to a decrease in the total phenol content of cloudy juice, while high-pressure homogenization at 200 bar has no effect on the total phenol content of cloudy juice (P≥0.05). However, the total phenol content of Gonggan cloudy juice treated with pressure ≥400 bar increased by 23.20±3.29 (μg / g) compared with NH treatment, indicating a certain gradient relationship between homogenization pressure and the total phenol content of Gonggan cloudy juice. The higher the pressure during HPH treatment, the more significant the increase in the total phenol content in the cloudy juice. Among the Gonggan cloudy juice treated with HPH, the 400-2, 600-2, and 600-3 groups had the highest total phenol content, reaching 112.86±2.10, 123.97±2.41, and 118.26±6.77 (μg / g), respectively.

[0048] 2.4 Results of the determination of soluble pectin content and pectin methyl esterase activity in Gonggan orange juice: The results of the determination of soluble pectin content and pectin methyl esterase activity in Gonggan orange juice are as follows: Figure 4 As shown. Figure 4The graph shows the changes in total pectin content and pectin lyase activity in the cloudy juice of Gonggan oranges after different high-pressure homogenization treatments. (The graph includes the following information:) Figure 4 (a) shows the change in total pectin content. Figure 4 (b) shows the changes in pectin methyl esterase activity.

[0049] Depend on Figure 4 (a) It can be seen that the soluble pectin content in the turbid juice of Gonggan oranges increased significantly after high pressure homogenization (P<0.05). Compared with the homogenization pressure treatment, the number of homogenization times had a more significant effect on pectin. The pectin content of the two HPH treatment groups increased by an average of 94.26% compared with NH. The soluble pectin content of the 400-2 group was the highest, reaching 307.32±12.54 µg / ml.

[0050] Depend on Figure 4 (b) It can be seen that, except for the 600-3 treatment group where PME enzyme activity increased by 28.04% compared to NH, the PME activity in the Gonggan cloudy juice under other homogenization conditions decreased or showed no significant change. The 200-2 group showed a 53.53% decrease compared to NH, with an activity of 0.79±0.09 μmol / min / g. This indicates that high-pressure homogenization has a certain inactivating effect on PME in Gonggan cloudy juice, but this inactivation effect is weakened by increasing HPH pressure and number of treatments. In the HPH treatment group, while PME activity increased with increasing homogenization pressure and number of treatments, the third HPH treatment always led to a significant decrease in soluble pectin content. The soluble pectin content in the 600 bar treatment group also decreased significantly with increasing PME activity, indicating that HPH treatment inhibits PME cleavage of pectin. The interaction between the third and 600 bar HPH treatments on the Gonggan cloudy juice system resulted in a greater change in soluble pectin than the effect of PME on pectin.

[0051] In conclusion, HPH can not only improve the symmetry of particle size distribution in Gonggan cloudy juice and enhance the dispersibility and stability of the Gonggan cloudy juice system, but also effectively improve the sensory and nutritional quality of Gonggan cloudy juice, thus promoting the development of HPH in the processing of Gonggan cloudy juice and other fruit juices.

[0052] Example 1: A method for preparing turbid juice of Gonggan oranges using high-pressure homogenization. Step S1: Use Deqing Gonggan (produced in Deqing County, Guangdong Province). Select mature Gonggan that are uniform in size, free from pests and diseases, and free from mechanical damage. Wash the mature Gonggan, cut them in half, remove the seeds, and then put them into a blender and blend for 5 minutes to obtain Gonggan suspension. Step S2: Add the 20% (mass percentage) Gonggan suspension obtained in step S1 to 80% (mass percentage) distilled water, then stir with a colloid mill for 3 min, and filter with a 100-mesh filter to obtain Gonggan turbid liquid. Step S3: The turbid liquid of tangerines obtained in step S2 is subjected to high-pressure homogenization twice at 400 bar and then sterilized to obtain the final product.

[0053] Example 2: A method for preparing turbid juice of Gonggan oranges using high-pressure homogenization. Step S1: Use Deqing Gonggan (produced in Deqing County, Guangdong Province). Select mature Gonggan that are uniform in size, free from pests and diseases, and free from mechanical damage. Wash the mature Gonggan, cut them in half, remove the seeds, and then put them into a blender and blend for 5 minutes to obtain Gonggan suspension. Step S2: Add the 20% (mass percentage) Gonggan suspension obtained in step S1 to 80% (mass percentage) distilled water, then stir with a colloid mill for 3 min, and filter with a 100-mesh filter to obtain Gonggan turbid liquid. Step S3: The turbid liquid of tangerines obtained in step S2 is subjected to high-pressure homogenization twice at 200 bar and then sterilized to obtain the final product.

[0054] Example 3: Preparation of a Gonggan fermentation powder Step S1: Use Deqing Gonggan (produced in Deqing County, Guangdong Province). Select mature Gonggan that are uniform in size, free from pests and diseases, and free from mechanical damage. Wash the mature Gonggan, cut them in half, remove the seeds, and then put them into a blender and blend for 5 minutes to obtain Gonggan suspension. Step S2: Add the 20% (mass percentage) Gonggan suspension obtained in step S1 to 80% (mass percentage) distilled water, then stir with a colloid mill for 3 min, and filter with a 100-mesh filter to obtain Gonggan turbid liquid. Step S3: The turbid citrus juice obtained in step S2 is subjected to high-pressure homogenization twice at 400 bar. After sterilization, it is inoculated with a brewer's yeast culture. The inoculation amount of the brewer's yeast culture is 5% of the total volume of the turbid citrus juice, and the viable count of the brewer's yeast culture is 1×10⁻⁶. 11 Oxygen was introduced at a concentration of CFU / mL, and fermentation was carried out at 30 °C for 18 h. After fermentation, *Lactobacillus plantarum* culture was inoculated at a concentration of 4% of the total volume of the orange juice, and the viable count of the *Lactobacillus plantarum* culture was 2.5 × 10⁻⁶. 10 After introducing oxygen for 2 hours, the mixture was sealed and fermented at 36 °C for 18 hours. The mixture was then centrifuged, and the supernatant was collected to obtain the Gonggan fermented product. This product was freeze-dried to obtain Gonggan fermented powder.

[0055] Example 4: Preparation of a fermented powder for tangerines Step S1: Use Deqing Gonggan (produced in Deqing County, Guangdong Province). Select mature Gonggan that are uniform in size, free from pests and diseases, and free from mechanical damage. Wash the mature Gonggan, cut them in half, remove the seeds, and then put them into a blender and blend for 5 minutes to obtain Gonggan suspension. Step S2: Add the 20% (mass percentage) Gonggan suspension obtained in step S1 to 80% (mass percentage) distilled water, then stir with a colloid mill for 3 min, and filter with a 100-mesh filter to obtain Gonggan turbid liquid. Step S3: The turbid citrus juice obtained in step S2 is subjected to high-pressure homogenization twice at 200 bar. After sterilization, it is inoculated with a brewer's yeast solution. The inoculation amount of the brewer's yeast solution is 6% of the total volume of the turbid citrus juice, and the viable count of the brewer's yeast solution is 1×10⁻⁶. 12 Oxygen was introduced at a concentration of CFU / mL, and fermentation was carried out at 30 °C for 18 h. After fermentation, *Lactobacillus plantarum* culture was inoculated at a concentration of 5% of the total volume of the orange juice. The viable count of the *Lactobacillus plantarum* culture was 2.5 × 10⁻⁶. 11 After introducing oxygen for 2 hours, the mixture was sealed and fermented at 36 °C for 18 hours. The mixture was then centrifuged, and the supernatant was collected to obtain the Gonggan fermented product. This product was freeze-dried to obtain Gonggan fermented powder.

[0056] Example 5: A composition The composition comprises the following components and their parts by weight: 16 parts of mandarin orange fermentation powder, 8 parts of dried plum extract and 6 parts of licorice extract; The Gonggan fermentation powder is the Gonggan fermentation powder prepared in Example 3; The preparation method of the plum extract is as follows: Take dried plums, crush them to obtain plum powder, add the plum powder to a 75% ethanol solution, the ratio of plum powder to ethanol solution is 1 g: 6 mL, reflux extract three times at 70 ℃, 2 h each time, combine the extracts, filter, concentrate, freeze dry to obtain the final product.

[0057] The preparation method of the licorice extract is as follows: Take dried licorice root, wash it clean, crush it to obtain licorice powder, add distilled water, the ratio of licorice powder to distilled water is 1 g: 18 mL, sonicate at 50 ℃ for 50 min, the sonication power is 200W, filter, concentrate, freeze dry to obtain licorice extract.

[0058] Preparation process: Mix the fermented mandarin orange powder, dried plum extract, and licorice extract evenly, then granulate to obtain the final product.

[0059] Example 6: A composition The composition comprises the following components and their parts by weight: 10 parts of mandarin orange fermentation powder, 12 parts of dried plum extract and 8 parts of licorice extract; The Gonggan fermentation powder is the Gonggan fermentation powder prepared in Example 4; The preparation method of the plum extract is as follows: Take dried plums, crush them to obtain plum powder, add the plum powder to a 75% ethanol solution, the ratio of plum powder to ethanol solution is 1 g: 8 mL, reflux extract three times at 75 ℃, 2 h each time, combine the extracts, filter, concentrate, freeze dry to obtain the final product.

[0060] The preparation method of the licorice extract is as follows: Take dried licorice root, wash it clean, crush it to obtain licorice powder, add distilled water, the ratio of licorice powder to distilled water is 1 g: 20 mL, sonicate at 55 ℃ for 60 min, the sonication power is 300W, filter, concentrate, freeze dry to obtain licorice extract.

[0061] Preparation process: Mix the fermented mandarin orange powder, dried plum extract, and licorice extract evenly, then granulate to obtain the final product.

[0062] Experiment Example 1: Blood Sugar Lowering Experiment with Citrus Fermentation Powder 1. Experimental Method: Diabetic KM mice with blood glucose levels above 15 mmol / L were used to create a diabetes model. They were divided into 5 experimental groups (n=10 per group) and 10 normal KM mice were used as a control group. The experimental groups were administered the drug via gavage, while the control group was administered an equal volume of saline via gavage. The drugs were administered once daily for one month. Fasting blood glucose levels were measured 12 hours after the last administration.

[0063] The experimental groups are divided as follows: Positive control group: metformin was administered by gavage at a dose of 200 mg / kg; Experimental group 1: Gavage administration of Gonggan fermented powder (Gonggan fermented powder prepared in Example 3), the dosage was 300 mg / (kg·d); Experimental group 2: Gavage administration of Prunus mume extract (Prunus mume extract prepared in Example 5) at a dose of 300 mg / (kg·d); Experimental group 3: Gavage administration of licorice extract (licorice extract prepared in Example 5) at a dose of 300 mg / (kg·d); Experimental group 4: Gavage composition (the composition prepared in Example 5), with a dosage of 300 mg / (kg·d).

[0064] 2. Experimental Results: The experimental results are shown in Table 4.

[0065] Table 4. Experimental data on blood glucose lowering effect As shown in Table 4, the fermented mandarin orange powder prepared in this invention can effectively reduce blood glucose levels in diabetic KM model mice, indicating that the fermented mandarin orange powder has the effect of improving hyperglycemia. When the fermented mandarin orange powder is mixed with plum extract and licorice extract, the three interact synergistically to enhance the hypoglycemic effect, resulting in a significant hypoglycemic effect.

[0066] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing tangerine juice using high-pressure homogenization, characterized in that, Includes the following steps: Step S1: Wash the ripe tangerines, cut them in half, remove the seeds, and then put them into a blender and blend for 4-6 minutes to obtain a tangerine suspension. Step S2: Add the Gonggan suspension obtained in step S1 to distilled water, then stir with a colloid mill for 2-4 minutes, filter, and obtain Gonggan turbid liquid. Step S3: The turbid liquid of tangerines obtained in step S2 is subjected to high-pressure homogenization and sterilization to obtain the final product.

2. The method for preparing Gonggan orange juice by high-pressure homogenization as described in claim 1, characterized in that, In step S2, the mass ratio of the tangerine suspension to distilled water is 1:

4.

3. The method for preparing Gonggan orange juice by high-pressure homogenization as described in claim 1, characterized in that, The conditions for high-pressure homogenization in step S3 are: 1 to 3 treatments at 200 to 600 bar.

4. The method for preparing Gonggan orange juice by high-pressure homogenization as described in claim 1, characterized in that, The sterilization process in step S3 also includes fermentation treatment, specifically: inoculating the sterilized Gonggan turbid juice with brewer's yeast culture, introducing oxygen, and fermenting at a temperature of 28~33 ℃ for 12~24 h. After fermentation, inoculating with Lactobacillus plantarum culture, introducing oxygen for 1~3 h, sealing, and fermenting at a temperature of 35~37 ℃ for 12~24 h, centrifuging, taking the supernatant to obtain Gonggan enzyme, freeze-drying to obtain Gonggan fermentation powder.

5. The method for preparing Gonggan orange juice by high-pressure homogenization as described in claim 4, characterized in that, The inoculation amount of the brewer's yeast solution is 4-6% of the total volume of the Gonggan orange juice, and the viable count of the brewer's yeast solution is 1×10⁻⁶. 10 ~1×10 12 cfu / mL.

6. The method for preparing Gonggan orange juice by high-pressure homogenization as described in claim 4, characterized in that, The inoculation amount of the *Lactobacillus plantarum* bacterial solution is 3-6% of the total volume of the orange juice, and the viable count of the *Lactobacillus plantarum* bacterial solution is 2.5 × 10⁻⁶. 9 ~2.5×10 11 cfu / mL.

7. A composition, characterized in that, It consists of the following components and their weight proportions: 10-16 parts of tangerine fermentation powder, 8-12 parts of dried plum extract, and 6-8 parts of licorice extract.

8. The composition according to claim 7, characterized in that, The preparation method of the plum extract is as follows: Take dried plums, crush them to obtain plum powder, add the plum powder to an ethanol solution with a volume concentration of 65-75%, and reflux extract 2-3 times at a temperature of 65-75 ℃, each time for 1-2 hours. Combine the extracts, filter, concentrate, and freeze dry to obtain the final product.

9. The composition according to claim 8, characterized in that, The ratio of the dried plum powder to the ethanol solution is 1g:6~8mL.

10. The composition according to claim 7, characterized in that, The preparation method of the licorice extract is as follows: Take dried licorice root, wash it clean, crush it to obtain licorice powder, add distilled water, the ratio of licorice powder to distilled water is 1 g: 15~20 mL, sonicate at 45~55 ℃ for 40~60 min, the sonication power is 200~300 W, filter, concentrate, freeze dry to obtain licorice extract.

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