Preparation method of avocado soup rich in eucommia seeds

Abstract

The invention discloses a preparation method of avocado soup rich in eucommia ulmoides seeds, which comprises the following steps: modifying chickpea protein isolate (CPI) through dynamic high-pressure microjet (DHPM), assisting grafting modification of CPI and arabinose (AB) by DHPM, preparing nano-emulsion rich in eucommia ulmoides seed oil by using the modified chickpea protein isolate (CPI) as an emulsifier, and adding the nano-emulsion into the avocado soup to improve the fat-soluble nutrient content of the avocado soup.

Description

Technical Field

[0001] The invention relates to the technical field of fruit and vegetable juice processing, in particular to a method for preparing an eucommia seed-rich oily pear soup. Background Art

[0002] Snow pear is a plant of the Rosaceae family. It is rich in nutrients such as sugar, polyphenols, flavonoids, organic acids and multiple vitamins. It has health functions such as appetizing, digesting food, promoting body fluid and quenching thirst, and anti-inflammatory and wind-clearing. At present, the processing methods of pear soup mainly include boiling, stewing (hot steam heating) and baking (hot air baking). Different processing methods have different effects on the sensory and nutritional quality of pear soup. However, the current processing methods of pear soup are relatively cumbersome or require high equipment, and the nutrients in pear soup are not fully released. In addition, as a water-soluble system, pear soup lacks fat-soluble nutrients, such as ω-3 polyunsaturated fatty acids and vitamin E, making it nutritionally unbalanced. Eucommia ulmoides is a single family, single genus and single species plant unique to my country, with a variety of pharmacologically and physiologically active ingredients. Eucommia ulmoides seed oil is rich in unsaturated fatty acids and fat-soluble vitamins, of which the content of α-linolenic acid is as high as about 60%. α-linolenic acid belongs to the ω-3 polyunsaturated essential fatty acid and has a variety of biological functional activities, such as regulating blood lipids, improving immune status, enhancing cognition and optimizing neuromuscular function. In 2019, Eucommia seed oil was approved as a new food resource, but its water insolubility and the poor oxidative stability of the fat-soluble nutrients it contains make it easily destroyed in the food system, reducing its biological function. In addition, the fat-soluble nutrients are easily affected by the cavity, gastric juice, and intestinal fluid environment, resulting in their low bioavailability. The above are the industry bottlenecks that limit the application of Eucommia seed oil in fruit and vegetable juice.

[0003] In recent years, the development of the preparation technology of oil-in-water (O / W) Pickering emulsions has led to their continuous application in the food field, providing technical support for solving the stability and bioavailability problems of fat-soluble nutrients. Emulsifiers affect the formation and stability of emulsions by regulating the oil-water interface properties. Ideal emulsifiers can quickly adsorb on the oil-water interface, reduce interfacial tension, and form a protective layer on the oil surface. Plant proteins, as natural amphiphilic macromolecules, have high biocompatibility, good biodegradability and a wide range of technical functions, and are therefore widely used in the preparation of food emulsions. CPI is a new type of plant protein resource with the advantages of high bioavailability, balanced essential amino acids and low sensitivity. However, due to many factors, such as anti-nutritional factors and the destruction of proteins by extraction methods, the emulsification and antioxidant properties of CPI are reduced, limiting its scope of application. Glycosylation modification is an economical and environmentally friendly chemical method based on the Maillard reaction mechanism, which allows proteins and sugars to form protein-sugar complexes through covalent bonds. It is green, natural, low-cost and highly safe. Protein glycosylation can significantly improve the solubility, emulsification and antioxidant activity of proteins. The disulfide bonds in proteins wrap the hydrophobic groups of proteins inside, which directly limits the grafting efficiency of proteins and sugars. Currently, physical methods such as ultrasound, microwaves and high-pressure homogenization are often used for pretreatment to fully stretch the secondary structure of proteins to improve the grafting efficiency. However, research on DHPM treatment of CPI and DHPM-assisted CPI glycosylation has not been reported.

[0004] Based on the above background, the present application first uses a high temperature and high pressure method to prepare pear soup to increase the content of antioxidant active ingredients (polyphenols and flavonoids) in the pear soup, and then uses DHPM to treat CPI and DHPM-assisted CPI glycosylation to improve the protein interface properties, thereby preparing a stable nanoemulsion rich in eucommia seed oil and adding it to the pear soup, and using high-pressure homogenization technology to prepare pear soup rich in eucommia seed oil. Summary of the invention

[0005] The invention proposes a processing method for pear soup rich in fat-soluble nutrients, so as to solve the industrial problem that fruit and vegetable juice drinks in the current market lack fat-soluble nutrients and break through the technical bottleneck of low bioavailability of fat-soluble nutrients.

[0006] The present invention prepares an O / W type nanoemulsion rich in eucommia seed oil based on oil-water interface design, adds it to snow pear soup, and prepares pear soup rich in fat-soluble nutrients by means of high-pressure homogenization technology, and analyzes the stability and release law of fat-soluble nutrients in pear soup. The present invention can greatly improve the fat-soluble nutrients in pear soup and improve its stability and delivery efficiency. On the one hand, the present application provides a preparation method of a nanoemulsion rich in eucommia seed oil, the preparation method comprising: 1) preparing CPI into a protein suspension, treating it with DHPM, and then freeze-drying it into a protein powder; 2) re-preparing the protein powder obtained in step 1) into a protein suspension, adding AB to the suspension, reacting at 50-90°C for 50-200min, and freeze-drying to obtain glycosylated protein, 3) preparing the protein obtained in step 2) into a suspension, adding eucommia seed oil, and obtaining a nanoemulsion by high-speed shearing.

[0007] Further, the method comprises that in the step 1), DHPM is treated at 50-400Mpa and the automatic cycle treatment is performed 1-10 times. The DHPM treatment is preferably 80-300Mpa; preferably 100-250Mpa; preferably 100-200Mpa. The automatic cycle treatment is preferably 2-9 times; preferably 3-8 times; preferably 4-7 times; preferably 4-6 times.

[0008] Furthermore, the concentration of the protein suspension reconstituted in step 2) is 1-30 mg / mL; preferably 5-25 mg / mL; preferably 5-20 mg / mL; preferably 5-15 mg / mL; preferably 8-12 mg / mL.

[0009] Furthermore, in step 2), AB is added to the suspension at a mass ratio of protein to sugar of 1:0.5-6. Preferably 1:0.5-5; preferably 1:0.5-4; preferably 1:0.8-4; preferably 1:1-3.

[0010] Further, in step 2), the reaction is carried out at 60-90°C for 50-180 min; preferably at 60-85°C for 60-150 min; preferably at 70-85°C for 60-120 min; preferably at 75-85°C for 60-120 min; preferably at 75-85°C for 70-110 min; preferably at 75-85°C for 80-100 min.

[0011] Further, in step 3), the protein obtained in step 2) is prepared into a 1% to 10% suspension, and 5-25% (w / v) eucommia seed oil is added; preferably, a 1% to 8% suspension, 5-20% (w / v) eucommia seed oil; preferably, a 1% to 7% suspension, 10-18% (w / v) eucommia seed oil; preferably, a 1% to 6% suspension, 12-18% (w / v) eucommia seed oil; preferably, a 1% to 5% suspension, 12-16% (w / v) eucommia seed oil. In another aspect of the present application, a method for preparing pear soup rich in eucommia seed oil is provided, comprising: mixing the pear soup with the aforementioned nanoemulsion rich in eucommia seed oil, and obtaining the mixture after homogenization.

[0012] Furthermore, the ratio of pear soup to the nanoemulsion is 50-200:1; preferably 80-130:1; preferably 90-120:1; preferably 90-110:1.

[0013] Furthermore, the homogenization pressure is 50-300 MPa; preferably 50-250 MPa; preferably 50-200 MPa; preferably 100-150 MPa.

[0014] Furthermore, the number of homogenization cycles is 1-10 times; preferably 2-8 times; preferably 3-6 times; preferably 3-5 times.

[0015] Furthermore, the pear soup preparation method comprises: cutting pear pieces into pieces, draining water and freezing, boiling sugar water, adding the sugar water to the pear pieces, high temperature treatment, and filtering to obtain pear soup. Beneficial effects: Compared with the traditional process of boiling pear soup, high temperature and high pressure treatment after freezing of pear pieces helps to break up the pear tissue cells and fully release polyphenols and flavonoids. The pear soup prepared by this method has high antioxidant activity and is simple to operate. On the other hand, DHPM treatment increases the sugar grafting degree of CPI, improves the interfacial properties of CPI, and thus improves the stability of the nanoemulsion and the delivery efficiency of fat-soluble nutrients, making up for the lack of fat-soluble nutrients in traditional pear soup on the market and its low bioavailability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 Effects of different DHPM pressures and CPI to AB mass ratios on protein grafting degree.

[0018] Figure 2 Effect of different sugar grafting degrees on the emulsification of CPI.

[0019] Figure 3 Effect of different sugar grafting degrees on the oil holding capacity of CPI.

[0020] Figure 4 Effect of different sugar grafting degrees on the interfacial tension of CPI.

[0021] Figure 5Effects of different treated proteins and their concentrations on the embedding efficiency of Eucommia ulmoides seed oil.

[0022] Figure 6 Effects of different processing methods on the contents of polyphenols and total flavonoids in pear soup.

[0023] Figure 7 Effects of different processing methods on the DPPH radical scavenging ability of pear soup.

[0024] Figure 8 Photostability of Eucommia seed-enriched oil pear soup prepared with different proteins and homogenization pressures.

[0025] Fig. 9 Thermal stability of Eucommia seed-enriched oil pear soup prepared with different proteins and homogenization pressures.

[0026] Fig.10 Storage stability of Eucommia seed-enriched oily pear soup prepared with different proteins.

[0027] Fig.11 Release rate of free fatty acids (FFA) during in vitro digestion of Eucommia ulmoides seed-enriched oil pear soup prepared with different proteins;

[0028] Fig.12 Process flow chart of pear soup rich in eucommia seed oil. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described below in conjunction with the drawings in the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Example 1

[0030] The preparation of nanoemulsion rich in Eucommia ulmoides seed oil is as follows: (1) CPI was added to deionized water and stirred at 40 °C for 30 min to fully dissolve the protein to prepare a 4 mg / mL protein suspension. The suspension was cooled to room temperature and treated with DHPM at pressures of 100 Mpa, 150 Mpa and 200 Mpa, respectively. Each pressure was automatically cycled for 5 times, and the treated protein solution was freeze-dried into powder. CPI treated with CPI and DHPM at different pressures was prepared into a 10 mg / mL protein suspension using deionized water. AB was added to the suspension at a protein to sugar mass ratio of 1:1, 1:2 and 1:3, and stirred for 3 h to mix the protein and sugar. The reaction was carried out in a water bath at 80 °C for 90 min. After the reaction was completed, the reaction was immediately terminated in an ice water bath to obtain a CPI-AB grafted product. The degree of glycosylation of each reaction product was then determined. Glycosylated proteins with grafting degrees of 9%, 18% and 29% were prepared into 2%, 3% and 4% suspensions, respectively, and 15% (w / v) Eucommia seed oil was added. The suspensions were treated with a high-speed shear at 10,000 r / min for 2 min to obtain uniform Eucommia seed oil nanoemulsions. The encapsulation efficiency of Eucommia seed oil in the nanoemulsions was determined. The above experimental structure optimization was used to optimize the DHPM pressure, grafting degree of glycosylated proteins and protein concentration.

[0031] (2) Protein property determination and nanoemulsion embedding rate detection Determination of grafting degree: The determination of grafting degree adopts the method of o-phthalaldehyde (OPA), 40 mg of o-phthalaldehyde dissolved in 1 ml of methanol is mixed with 25 ml of 0.1 mol / L sodium tetraborate buffer (PH=9.5), 25 ml of 20% (w / w) sodium dodecyl sulfate solution and 0.1 m ß-mercaptoethanol. The volume is fixed in a 50 ml volumetric flask, 4 ml of OPA reagent is mixed with 0.2 ml of 2 mg / ml grafted material, distilled water is used as a control, reacted at 35℃ for 2 min, and the absorbance value is measured at 340 nm by UV spectrophotometer. Grafting degree (%) = (A0-A1) / A0×100 Where: A0 and A1 are the absorbance of untreated CPI and glycosylated protein at 340 nm, respectively.

[0032] Emulsification determination: 9 mL of sample (1 mg / mL) was mixed with 3 mL of soybean oil and homogenized at 20 Kr / min for 1 min. At 0 min and 10 min, 50 µL of solution was drawn from the bottom of the container to 5 mL of SDS solution (0.1%). After oscillation and mixing, the absorbance was measured at 500 nm and recorded as A0, A 10 .

[0033] ;

[0034] Where: A0, absorbance of the emulsion at 0 min; A 10 , absorbance after standing for 10 min; D, dilution factor; C, protein concentration (g / mL); φ, oil phase volume fraction; L, cuvette light path.

[0035] Oil holding capacity determination: 0.02 g sample was recorded as m3, placed in a centrifuge tube as m4, 2 mL soybean oil was added, dispersed at 20,000 r / min for 1 min in a high-speed disperser, centrifuged at 4500 r / min for 15 min, and the residual oil was sucked off as m5.

[0036] ;

[0037] Interfacial tension determination: The hanging drop method of the fully automatic interfacial rheometer was used to determine the change of interfacial tension with time. A certain volume of sample (0.005%) was drawn with a microsyringe, the needle was inserted into a glass dish containing soybean oil, and a drop of about 12 µL was dripped out. The interfacial tension of the drop was collected within 3500 s.

[0038] Determination of embedding rate: The free eucommia seed oil in the nanoemulsion was extracted by dichloromethane, and the FFA content was determined according to GB5009.168-2016 “National Food Safety Standard Method for Determination of Fatty Acids in Food”, and the embedding rate was calculated by the FFA content.

[0039] (3) Experimental results The effects of different DHPM pressures and CPI / AB mass ratios on protein grafting degree were investigated. Figure 1 ).Depend on Figure 1 It can be seen that the CPI grafting degree is the highest when the DHPM pressure is 150 MPa and the ratio of protein to sugar is 1:2. The interfacial properties such as emulsification, oil holding capacity and interfacial tension of chickpea protein with different grafting degrees (9%, 18% and 29%) are compared. Figure 2 It can be seen that the emulsifying property of the glycosylated protein with a grafting degree of 29% (CPI-AB-29%) is significantly higher than that of the protein with a grafting degree of 18% (CPI-AB-18%) and 9% (CPI-AB-9%); similarly, the oil holding capacity of CPI-AB-29% is significantly higher than that of CPI-AB-18% and CPI-AB-9% ( Figure 3 ); while CPI-AB-29% exhibited the lowest interfacial tension, followed by CPI-AB-18% and CPI-AB-9% ( Figure 4 ).

[0040] Nanoemulsions enriched with eucommia seed oil were prepared using CPI, DHPM-treated protein, CPI-AB-9%, CPI-AB-18% and CPI-AB-29% as emulsifiers. The addition amount of eucommia seed oil was 15% (w / v), and the concentrations of glycoprotein were 2%, 3% and 4% (w / v), respectively. Figure 5 It can be seen that the 3% glycoprotein concentration has the highest embedding rate for 15% eucommia seed oil. Therefore, the pressure of 150 MPa and the mass ratio of CPI to AB of 1:2 are preferred as the glycosylation modification conditions; 3% CPI-AB-29% glycosylated protein is used to prepare nanoemulsion. Example 2

[0041] The preparation steps of snow pear soup are as follows: (1) Cut the snow pear into 2~3 cm pieces 3 100 g frozen pear pieces were added with 300 g sugar water to completely immerse the pear pieces. The pear pieces were treated at 121°C and 0.1 Mpa for 10 min, 20 min and 30 min respectively, and the pear soup was obtained by filtering. The pear soup was prepared by traditional boiling method for comparison. The only difference was that 100 g pear pieces were directly boiled with water and sugar without freezing or high temperature and high pressure treatment.

[0042] (2) Determination of physical and chemical properties of pear soup The polyphenol content was determined by the Folin-Ciocalteu method, the total flavonoid content was determined by the nitrite-aluminum nitrate-sodium hydroxide colorimetric method, and the DPPH free radical scavenging ability was determined using an enzyme-labeled instrument.

[0043] (3) Experimental results The effects of traditional boiling and pear pre-freezing combined with high temperature and high pressure (CF+HTP) treatment for 10 min (CF+HTP-10), 20 min (CF+HTP-20) and 30 min (CF+HTP-30) on the physicochemical properties of pear soup were compared. Figure 6 It can be seen that the polyphenol and total flavonoid contents of the pear soup processed by CF+HTP were significantly higher than those prepared by the traditional cooking method. There was no significant difference in the polyphenol and total flavonoid contents of the pear soup processed by CF+HTP-30 and CF+HTP-20, but they were significantly higher than those prepared by CF+HTP-10. In addition, the results of the DPPH scavenging ability of the pear soup were consistent with the results of its polyphenol and total flavonoid contents ( Figure 7 ), so considering the energy consumption, the high temperature and high pressure treatment conditions were selected as: 121℃, 0.1 Mpa, 20 min. Example 3

[0044] according to Figure 1 Processing technology for preparing snow pear soup rich in eucommia seed oil, the steps are as follows: (1) Preparation of pear soup. Use fresh snow pear as the raw material, wash and drain with clean water, remove the core, and cut into 2~3 cm 3 The pear pieces were immediately soaked in 0.3% sodium ascorbate for 10 min. The pear pieces were drained and frozen at -80℃ for 8 h. Sugar water was boiled with a ratio of 1:3 (w / w) of white sugar to water. After boiling, the foam was removed and then boiled over low heat for 10 min. The sugar water was cooled for later use. 300 g of sugar water was added to 100 g of frozen pear pieces to completely immerse the pear pieces. The pear soup was filtered out at 121℃ and 0.1 Mpa for 20 min.

[0045] (2) Preparation of nanoemulsion enriched with Eucommia ulmoides seed oil.

[0046] CPI was prepared into a 3% suspension, and 15% (w / v) Eucommia seed oil was added. The suspension was treated with a high-speed shearing machine at 10,000 r / min for 2 min to obtain a uniform Eucommia seed oil nanoemulsion.

[0047] (3) The ratio of the prepared pear soup to the nanoemulsion was 100:1. The mixture was stirred at 35°C for 30 min to allow the emulsion and juice to be fully mixed. The mixture was then sterilized by high-pressure homogenization at a homogenization pressure of 100 MPa and the number of cycles was 4. Snow pear soup rich in eucommia seed oil was obtained.

[0048] (4) Determination of pear soup stability and FFA release kinetics analysis.

[0049] Pear soup was irradiated under ultraviolet lamp (30W, 254 nm) at 25℃ for 10 h. The distance between the ultraviolet lamp and the sample was set to 7 cm. The FFA retention rate in the pear soup was determined to evaluate its photostability. The pear soup rich in eucommia seed oil was incubated at 4℃, 25℃ and 60℃ for 2 h, and then the fatty acid content was determined. The thermal stability of the pear soup was evaluated by calculating the FFA retention rate. The pear soup was packaged in bottles and stored at 25℃ for 140 days. The FFA retention rate in the pear soup was determined to evaluate its storage stability.

[0050] In vitro simulated digestion and FFA release kinetics of pear soup. Simulated gastric fluid: Take 16.0 mL of 23.5% (v / v) dilute hydrochloric acid and add it to 700 mL of deionized water, then add 10 g of pepsin, shake well, dilute to 1 L and adjust its pH to 2. Simulated intestinal fluid: Take 3.2 g KH2PO4 and dissolve it in 250 mL of deionized water, adjust its pH to 6.8, add 100 mL of 1% (w / v) pancreatic enzyme solution to the H2PO4 solution, dilute to 500 mL, and adjust the pH to 6.8.

[0051] Gastric digestion stage: 20 mL of pear soup was mixed with simulated gastric juice at a ratio of 1:1 (v / v), and its pH was adjusted to 2.5. Then, it was incubated at a constant temperature of 37°C for 2 h to complete gastric juice digestion. At a constant temperature of 37°C, 30 mL of the sample was adjusted to pH 7.0, 4 mL of bile extract and 1 mL of CaCl2 (110 mg / mL) solution were added, and 2.5 mL of freshly prepared lipase solution (0.06 g dissolved in 2.5 mL of pH=7 phosphate buffer) was added, and the pH of the mixed solution was adjusted to 7. The 0.05 mol / L NaOH solution required for lipid digestion to release FFA within 2 h was recorded. FFA release rate = (V NaOH × C NaOH × M 油 )÷(2 × m 油 )× 100% Where: V NaOH is the NaOH consumption, L; C NaOH is the concentration of NaOH, mol / L; M 油 is the average relative molecular mass of eucommia seed oil, g / mol; m 油 is the mass of eucommia seed oil, g.

[0052] Same as Example 3, the only difference is that CPI treated with DHPM is used.

[0053] Same as Example 3, the only difference is that CPI with a grafting degree of 29% is used.

[0054] Same as Example 3, the only difference is that the high-pressure homogenization pressure is 150 Mpa.

[0055] The same as comparative example 1, the only difference is that the high-pressure homogenization pressure is 150 MPa.

[0056] The same as comparative example 2, the only difference is that the high-pressure homogenization pressure is 150 MPa.

[0057] The stability and in vitro digestion FFA release of pear soup rich in Eucommia seed oil under different homogenization pressures (100 MPa and 150 MPa) were compared between CPIs with different treatments, such as CPI, DHPM-treated protein and 29% grafted protein (CPI-AB-29%). Figure 8 and Fig. 9 It can be seen that under the same pressure, the light and heat stability of pear soup prepared by DHPM protein and CPI-AB-29% are significantly higher than that of untreated CPI, and the pear soup prepared by CPI-AB-29% has the highest stability. In addition, the stability of pear soup prepared by homogenization pressure of 100 MPa and 150 MPa is not significant. Therefore, considering the energy consumption, the preferred homogenization pressure is 100 MPa. Subsequently, the storage stability and in vitro digestibility of pear soup prepared under a homogenization pressure of 100 MPa were investigated. Fig.10 and Fig.11 It can be seen that the pear soup prepared with CPI-AB-29% and DHPM protein has the best storage stability, and the storage period is 3 months longer than that of the pear soup prepared with CPI; the in vitro simulated digestion experiment shows that both CPI-AB-29% and DPHM protein can inhibit the release of fatty acids in eucommia seed oil, and the pear soup prepared with CPI-AB-29% has the best inhibitory effect.

Claims

1. A method for preparing a nanoemulsion rich in eucommia seed oil, characterized in that: The preparation method comprises: 1) preparing chickpea protein isolate into a protein suspension, treating it with dynamic high-pressure microfluidization, and then freeze-drying it into a protein powder; 2) preparing the protein powder obtained in step 1) into a protein suspension, adding arabinose to the suspension, reacting at 50-90° C. for 50-200 minutes, and freeze-drying to obtain a glycosylated protein; 3) preparing the protein obtained in step 2) into a suspension, adding eucommia seed oil, and obtaining a nanoemulsion by high-speed shearing.

2. The preparation method according to claim 1, characterized in that: In the step 1), the dynamic high-pressure microfluidization is processed at 80-300 MPa and the automatic cycle is performed 3-8 times.

3. The preparation method according to claim 1, characterized in that: The concentration of the protein suspension reconstituted in step 2) is 5-20 mg / mL.

4. The preparation method according to claim 1, characterized in that: In the step 2), arabinose is added to the suspension at a mass ratio of protein to sugar of 1:0.5-6.

5. The preparation method according to claim 1, characterized in that: In the step 3), the protein obtained in step 2) is prepared into a 1% to 10% suspension, and 5-25% (w / v) eucommia seed oil is added.

6. The nanoemulsion rich in eucommia seed oil prepared by the preparation method according to claim 1.

7. A method for preparing pear soup rich in eucommia seed oil, characterized in that: The preparation method comprises: mixing pear soup with the nanoemulsion rich in eucommia seed oil as claimed in claim 1, and obtaining the mixture after homogenization.

8. The preparation method according to claim 7, characterized in that: The ratio of pear soup to the nanoemulsion is 50-200:

1.

9. The preparation method according to claim 7, characterized in that: The homogenization pressure is 50-300 MPa, and the homogenization cycle times are 3-6 times.

10. The preparation method according to claim 7, characterized in that: The pear soup preparation method comprises: cutting pear pieces into pieces, filtering water and freezing, boiling sugar water, adding the sugar water into the pear pieces, high-temperature treatment, and filtering to obtain the pear soup.

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