A passion fruit flavor concentrate and a method for preparing the same

Abstract

The application discloses a passion fruit flavor concentrate and a preparation method thereof, and relates to the technical field of food processing. The preparation method of the passion fruit flavor concentrate is as follows: fresh passion fruits are cleaned and disinfected, then low-temperature cold pressing is carried out under nitrogen protection, filtration is carried out, and a composite antioxidant is added to obtain passion fruit original juice; the passion fruit original juice is placed in a falling film evaporator, preheating, vacuum degassing, heating evaporation and condensation are carried out, and then passion aroma recovery liquid and de-aroma fruit juice are collected; the passion aroma recovery liquid is wrapped with beta-cyclodextrin to prepare aroma particles; the de-aroma fruit juice is subjected to low-temperature vacuum concentration until the soluble solids are greater than or equal to 60%, and then de-aroma concentrated juice is obtained; the de-aroma concentrated juice is uniformly mixed with high-ester pectin, and then aroma particles are added and homogenized to obtain aroma-enhanced concentrated juice; sterilization and filling are carried out, and the passion fruit flavor concentrate is obtained. The passion fruit flavor concentrate can not only well maintain the aroma and taste of the concentrated juice, but also make the concentrated juice system more uniform and stable, and the concentrated juice will not be flocculated or precipitated during long-term storage.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a passion fruit flavor concentrate and its preparation method. Background Technology

[0002] Passion fruit (Passiflora edulis Sims.), also known as granadilla, is a perennial vine belonging to the genus Passiflora in the family Passifloraceae, widely distributed in tropical and subtropical regions. Its juice is renowned worldwide for its rich content of vitamins, amino acids, minerals, and other nutrients, and for its natural and unique color, aroma, and flavor, earning it the title of "King of Juices."

[0003] Traditional passion fruit juice production typically employs hot pressing, which involves pressing the fruit and then concentrating it at temperatures above 80°C. However, this high-temperature process not only leads to a significant loss of volatile aromatic compounds but can also trigger Maillard reactions between sugars and amino acids, as well as oxidative browning, resulting in a burnt flavor that severely impacts the juice's sensory quality. Furthermore, the juice system exhibits poor colloidal stability, leading to sedimentation and stratification during its shelf life, resulting in decreased product quality and a shortened shelf life.

[0004] To address the issues of aroma loss and browning during traditional heat processing, researchers have made the following improvements to the preparation method of passion fruit juice: For example, Chinese patent CN 117502581A discloses a passion fruit juice and its preparation method, employing membrane separation technology for cold concentration of the juice. Compared to heat concentration, this significantly reduces the loss of volatile flavor compounds. However, membrane concentration increases equipment cleaning frequency and shortens membrane lifespan. Chinese patent CN 106165875A discloses a method for preparing passion fruit extract, where passion fruit is juiced, the pulp is extracted with ethanol to obtain aroma compounds, which are then mixed with the juice and concentrated using a membrane method to preserve the aroma. However, extraction solvents such as ethanol can affect the flavor and taste of the juice. Chinese patent CN105167041A discloses a passion fruit juice and its preparation method, which uses low-temperature cold pressing to reduce browning. However, cold-processed juice is prone to separation of pulp and clear juice during long-term storage, forming sediment or stratification, severely affecting its commercial appearance and consumer acceptance. Therefore, further improvements are needed. Summary of the Invention

[0005] To address the above shortcomings, this invention provides a passion fruit flavor concentrate and its preparation method, solving the problems of significant aroma loss, easy browning, and poor stability in existing passion fruit concentrates during preparation. The specific technical solution is as follows: A method for preparing passion fruit flavor concentrate includes the following steps: (1) Raw material pretreatment: Select mature and fresh passion fruit without mechanical damage or pests and diseases for cleaning and disinfection; (2) Juicing: The cleaned and disinfected passion fruit is cold-pressed at low temperature under nitrogen protection, filtered, and a compound antioxidant is added and mixed to obtain passion fruit juice. (3) Aroma recovery: The passion fruit juice is placed in a falling film evaporator, and after preheating, vacuum degassing, heating evaporation and condensation, the aroma recovery liquid and the deodorized juice are collected separately and stored at 4-10℃ for later use. (4) Aroma encapsulation: First, add β-cyclodextrin to water at 50-60℃ and stir until completely dissolved, and continue stirring until the temperature drops to 40-45℃ to obtain β-cyclodextrin solution; slowly add the aroma recovery liquid dropwise to the β-cyclodextrin solution while stirring vigorously at a speed of 500-1000 rpm for 1-2 hours, cool naturally to room temperature, and refrigerate at 4-8℃ for 12-24 hours. After refrigeration, centrifuge at 3000-4000 rpm for 10-15 minutes, collect the precipitate, dry it at 40-45℃, and grind it into fine powder to obtain aroma particles; (5) Concentration: The deodorized juice is concentrated under low temperature vacuum until the soluble solids content is ≥60% to obtain deodorized concentrated juice; (6) Backfilling and flavor enhancement: First, mix the deodorized concentrated juice with 0.1%-0.5% of high-ester pectin in the total amount of the deodorized concentrated juice, and then shear it at high speed at 3000-5000 rpm for 3-5 minutes to form a uniform and fine slurry; then add 1-3% of the weight of the slurry of aroma particles to the slurry, and homogenize it at 10-15 MPa using a low-pressure homogenizer to obtain the flavor-enhanced concentrated juice; (7) Sterilization and filling: The flavor-enhancing concentrated juice is pasteurized and filled to obtain the passion fruit flavor concentrate.

[0006] Further, in step (1), the cleaning and disinfection involves rinsing with running water and then soaking in 4-6 ppm ozone water for 1-2 minutes for disinfection.

[0007] Furthermore, in step (2), the temperature of the low-temperature cold pressing is 5-15℃.

[0008] Further, in step (2), the composite antioxidant is a mixture of glucose oxidase and sodium isoascorbate in a mass ratio of 1:(30-50), and the amount of the composite antioxidant added is 0.05-0.1% of the weight of the passion fruit juice.

[0009] Further, in step (3), the preheating temperature is 35-45℃; the vacuum degassing is to reduce the absolute pressure in the falling film evaporator to 4-8 kPa; the heating temperature for heating and evaporation is 30-50℃; and the condensation temperature is -5℃ to 5℃.

[0010] Further, in step (4), the weight ratio of β-cyclodextrin to water is 1:(6-8); the mass ratio of aroma recovery liquid to β-cyclodextrin liquid is 1:(50-60).

[0011] Furthermore, in step (4), the particle size of the aroma particles is less than 1 μm.

[0012] Furthermore, in step (5), the temperature of the low-temperature vacuum concentration is 40-45℃ and the absolute pressure is 6-8kPa.

[0013] This invention also provides a passion fruit flavor concentrate prepared by the method described above. This concentrate can be used as a food or food ingredient, specifically in dairy products, beverages, frozen foods, chocolate and confectionery products, baked goods, condiments, and other products.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention first recovers the aroma from passion fruit juice, then encapsulates the aroma-recovered liquid with β-cyclodextrin to obtain aroma particles. These aroma particles are then reintroduced into the concentrated juice. The β-cyclodextrin encapsulation maximizes the prevention of flavor substances from volatilization and oxidative degradation during concentration or storage. When used, the aroma particles in the passion fruit flavor concentrate dissolved in water, releasing a rich aroma. When not in use, the flavor substances are well preserved in the concentrate, preventing volatilization or oxidative deterioration. Furthermore, during the reintroduction of aroma, the de-fragrant concentrated juice is first mixed with high-ester pectin before adding the aroma particles. The addition of both high-ester pectin and aroma particles makes the juice system more homogeneous and stable, preventing flocculation or sedimentation during long-term storage and extending shelf life. Detailed Implementation

[0015] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Unless otherwise defined, all technical terms used below have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, all raw materials, reagents, instruments, and equipment used in the present invention are commercially available or can be prepared by existing methods.

[0016] Example 1 A method for preparing passion fruit flavor concentrate includes the following steps: (1) Raw material pretreatment: Select mature and fresh passion fruit without mechanical damage or pests and diseases. After washing with running water, soak in 4ppm ozone water for 1 minute for disinfection. Ozone can not only kill bacteria, but also oxidize and decompose residual ethylene to a certain extent, slow down the physiological metabolism of the fruit, and buy time for subsequent processing. (2) Juicing: The cleaned and disinfected passion fruit is cold-pressed at 5°C under nitrogen protection, filtered, and 0.05% of the weight of the passion fruit juice is added as a compound antioxidant. The mixture is then mixed to obtain passion fruit juice. The compound antioxidant is a mixture of glucose oxidase and sodium isoascorbate in a mass ratio of 1:30. The combined use of glucose oxidase and sodium isoascorbate in the compound antioxidant can better prevent browning of the juice. (3) Aroma recovery: The passion fruit juice is placed in a falling film evaporator, and after preheating, vacuum degassing, heating evaporation and condensation, the aroma recovery liquid and the deodorized juice are collected separately and stored at 4°C for later use. The preheating temperature is 35°C; the vacuum degassing involves reducing the absolute pressure in the falling film evaporator to 4 kPa; the heating temperature for heating and evaporation is 30°C; and the condensation temperature is -5°C to 5°C. (4) Aroma encapsulation: First, add β-cyclodextrin to water at 50°C and stir until completely dissolved. The weight ratio of β-cyclodextrin to water is 1:6. Continue stirring until the temperature drops to 40°C to obtain β-cyclodextrin solution. Slowly add the aroma recovery liquid to the β-cyclodextrin solution. The mass ratio of aroma recovery liquid to β-cyclodextrin solution is 1:50. Stir vigorously while adding the solution. The stirring speed is 500 rpm. Continue stirring for 2 hours. Allow the solution to cool naturally to room temperature. Place it in a refrigerator at 4°C and refrigerate for 12 hours. Centrifuge at 3000 rpm for 15 minutes. Collect the precipitate, dry it at 40°C, and grind it into fine powder to obtain aroma particles with a particle size of less than 1 μm. (5) Concentration: The deodorized juice is concentrated under low temperature vacuum at a temperature of 40°C and an absolute pressure of 8 kPa until the soluble solids content is ≥60% to obtain deodorized concentrated juice. (6) Backfilling and flavor enhancement: First, mix the deodorized concentrated juice with 0.1% of the total amount of high-ester pectin in the deodorized concentrated juice, and then shear it at 3000 rpm for 5 min to form a uniform and fine slurry; then add 1% of the weight of the aroma particles to the slurry, and homogenize it at 10 MPa using a low-pressure homogenizer to obtain the flavor-enhanced concentrated juice; (7) Sterilization and filling: The flavor-enhancing concentrated juice is pasteurized and filled to obtain the passion fruit flavor concentrate.

[0017] Example 2 A method for preparing passion fruit flavor concentrate includes the following steps: (1) Raw material pretreatment: Select mature and fresh passion fruit without mechanical damage or pests and diseases. After washing with running water, soak in 6ppm ozone water for 1 minute for disinfection. Ozone can not only kill bacteria, but also oxidize and decompose residual ethylene to a certain extent, slow down the physiological metabolism of the fruit, and buy time for subsequent processing. (2) Juicing: The cleaned and disinfected passion fruit is cold-pressed at 15°C under nitrogen protection, filtered, and 0.1% of the weight of the passion fruit juice is added as a compound antioxidant. The mixture is then mixed to obtain passion fruit juice. The compound antioxidant is a mixture of glucose oxidase and sodium isoascorbate in a mass ratio of 1:50. The combined use of glucose oxidase and sodium isoascorbate in the compound antioxidant can better prevent browning of the juice. (3) Aroma recovery: The passion fruit juice is placed in a falling film evaporator, and after preheating, vacuum degassing, heating evaporation and condensation, the aroma recovery liquid and the deodorized juice are collected separately and stored at 10°C for later use. The preheating temperature is 45°C; the vacuum degassing involves reducing the absolute pressure in the falling film evaporator to 8 kPa; the heating temperature for heating and evaporation is 50°C; and the condensation temperature is -5°C to 5°C. (4) Aroma encapsulation: First, add β-cyclodextrin to water at 60°C and stir until completely dissolved. The weight ratio of β-cyclodextrin to water is 1:8. Continue stirring until the temperature drops to 45°C to obtain β-cyclodextrin solution. Slowly add the aroma recovery liquid to the β-cyclodextrin solution. The mass ratio of aroma recovery liquid to β-cyclodextrin solution is 1:60. Stir vigorously while adding the solution. The stirring speed is 1000 rpm. Continue stirring for 1 hour. Allow the solution to cool naturally to room temperature. Place it in a refrigerator at 8°C and refrigerate for 12 hours. Centrifuge at 4000 rpm for 10 minutes, collect the precipitate, dry it at 45°C, and grind it into fine powder to obtain aroma particles with a particle size of less than 1 μm. (5) Concentration: The deodorized juice is concentrated under low temperature vacuum at a temperature of 45°C and an absolute pressure of 6 kPa until the soluble solids content is ≥60% to obtain deodorized concentrated juice. (6) Backfilling and flavor enhancement: First, mix the deodorized concentrated juice with 0.5% of the total amount of high-ester pectin in the deodorized concentrated juice, and then shear it at 5000 rpm for 3 minutes to form a uniform and fine slurry; then add 3% of the weight of the slurry of aroma particles to the slurry, and homogenize it at 15 MPa using a low-pressure homogenizer to obtain the flavor-enhanced concentrated juice; (7) Sterilization and filling: The flavor-enhancing concentrated juice is pasteurized and filled to obtain the passion fruit flavor concentrate.

[0018] Example 3 A method for preparing passion fruit flavor concentrate includes the following steps: (1) Raw material pretreatment: Select mature and fresh passion fruit without mechanical damage or pests and diseases. After washing with running water, soak in 4ppm ozone water for 2 minutes for disinfection. Ozone can not only kill bacteria, but also oxidize and decompose residual ethylene to a certain extent, slow down the physiological metabolism of the fruit, and buy time for subsequent processing. (2) Juicing: The cleaned and disinfected passion fruit is cold-pressed at 10°C under nitrogen protection, filtered, and 0.05% of the weight of the passion fruit juice is added as a compound antioxidant. The mixture is then mixed to obtain passion fruit juice. The compound antioxidant is a mixture of glucose oxidase and sodium isoascorbate in a mass ratio of 1:40. The combined use of glucose oxidase and sodium isoascorbate in the compound antioxidant can better prevent browning of the juice. (3) Aroma recovery: The passion fruit juice is placed in a falling film evaporator, and after preheating, vacuum degassing, heating evaporation and condensation, the aroma recovery liquid and the deodorized juice are collected separately and stored at 8°C for later use. The preheating temperature is 40°C; the vacuum degassing involves reducing the absolute pressure in the falling film evaporator to 7 kPa; the heating temperature for heating and evaporation is 40°C; and the condensation temperature is -5°C to 5°C. (4) Aroma encapsulation: First, add β-cyclodextrin to water at 55°C and stir until completely dissolved. The weight ratio of β-cyclodextrin to water is 1:7. Continue stirring until the temperature drops to 45°C to obtain β-cyclodextrin solution. Slowly add the aroma recovery liquid to the β-cyclodextrin solution. The mass ratio of aroma recovery liquid to β-cyclodextrin solution is 1:55. Stir vigorously while adding the solution. The stirring speed is 800 rpm. Continue stirring for 1.5 hours. Allow the solution to cool naturally to room temperature. Place it in a refrigerator at 8°C and refrigerate for 20 hours. Centrifuge at 3500 rpm for 15 minutes, collect the precipitate, dry it at 45°C, and grind it into fine powder to obtain aroma particles with a particle size of less than 1 μm. (5) Concentration: The deodorized juice is concentrated under low temperature vacuum at a temperature of 45°C and an absolute pressure of 8 kPa until the soluble solids content is ≥60% to obtain deodorized concentrated juice. (6) Backfilling and flavor enhancement: First, mix the deodorized concentrated juice with 0.3% of the total amount of high-ester pectin in the deodorized concentrated juice, and then shear it at 4000 rpm for 4 min to form a uniform and fine slurry; then add 2% of the weight of the slurry of aroma particles to the slurry, and homogenize it at 12 MPa using a low-pressure homogenizer to obtain the flavor-enhanced concentrated juice; (7) Sterilization and filling: The flavor-enhancing concentrated juice is pasteurized and filled to obtain the passion fruit flavor concentrate.

[0019] Comparative Example 1: Instead of first recovering the aroma and then backfilling, the traditional method was used to prepare the following: (1) Raw material pretreatment: Select mature and fresh passion fruit without mechanical damage or pests and diseases, wash it with running water, and then soak it in 4ppm ozone water for 2 minutes for disinfection; (2) Juicing: Under nitrogen protection, cold press the washed and disinfected passion fruit at 10°C, filter it, and add 0.05% of the weight of the passion fruit juice with a compound antioxidant, mix it well, and obtain passion fruit juice; (3) Concentration: Concentrate the passion fruit juice at low temperature in a vacuum. The temperature of the low temperature vacuum concentration is 45°C and the absolute pressure is 8kPa. Concentrate until the soluble solids are ≥60%; (4) Sterilization and filling: Pasteurize and fill the passion fruit juice to obtain the passion fruit concentrate.

[0020] Comparative Example 2: After aroma recovery, the material was directly backfilled without encapsulation. The specific preparation method was as follows: (1) Raw material pretreatment: Select mature and fresh passion fruit without mechanical damage or pests and diseases, wash with running water, and then soak in 4ppm ozone water for 2 minutes for disinfection. (2) Juicing: The cleaned and disinfected passion fruit is cold-pressed at 10°C under nitrogen protection, filtered, and 0.05% of the weight of the passion fruit juice is added as a compound antioxidant. The mixture is then mixed to obtain passion fruit juice. (3) Aroma recovery: The passion fruit juice is placed in a falling film evaporator, and after preheating, vacuum degassing, heating evaporation and condensation, the aroma recovery liquid and the de-aroma juice are collected and stored at 8°C for later use; the preheating temperature is 40°C; the vacuum degassing is to reduce the absolute pressure in the falling film evaporator to 7 kPa; the heating temperature for heating evaporation is 40°C; the condensation temperature is -5°C to 5°C; (4) Concentration: The deodorized juice is concentrated under low temperature vacuum at a temperature of 45°C and an absolute pressure of 8 kPa until the soluble solids content is ≥60% to obtain deodorized concentrated juice. (6) Backfilling and flavor enhancement: First, mix the deodorized concentrated juice with 0.3% of the total amount of high-ester pectin in the deodorized concentrated juice, and then shear it at 4000 rpm for 4 min to form a uniform and fine slurry; then add 10% of the weight of the aroma recovery liquid to the slurry, and homogenize it at 12 MPa using a low-pressure homogenizer to obtain the flavor enhancement concentrated juice; (7) Sterilization and filling: The flavor-enhancing concentrated juice is pasteurized and filled to obtain the passion fruit flavor concentrate.

[0021] Comparative Example 3: Gum arabic was used instead of β-cyclodextrin as the embedding material, and the other steps were the same as in Example 3.

[0022] Comparative Example 4: The particle size of the aroma particles was 2-3 μm, and the other steps were the same as in Example 3.

[0023] Comparative Example 5: Except for step (6), which is: first, add 2% of the weight of the deodorized concentrated juice to the deodorized concentrated juice, and shear it at 4000 rpm for 4 min to form a mixture, and then add 0.3% of the total weight of the deodorized concentrated juice and homogenize it at 12 MPa using a low-pressure homogenizer to obtain the flavor-enhanced concentrated juice; that is, add the aroma particles first and then add the high-fat pectin, and the other steps are the same as in Example 3.

[0024] Aroma and taste test: To demonstrate that the method of this invention can improve the quality of passion fruit concentrate, the applicant used a sensory evaluation method to score the sensory qualities of the passion fruit concentrates prepared in each embodiment and comparative example, including color, taste, aroma, texture, and morphology. The concentrates in each embodiment and comparative example were prepared using the same batch of Tainong No. 1 red passion fruit. Ten healthy evaluators were recruited and first informed of the scoring criteria (as shown in Table 1). Then, each group took 20 mL of concentrate that had been left at room temperature for 10 days and placed it in a colorless, transparent container. The container was placed in a bright area, and the color, texture, and impurities were observed visually. Next, water was added at room temperature to dilute it to 50 mL, the aroma was smelled, and the taste was evaluated after rinsing the mouth with warm water. Scores were then given according to the scoring criteria, and the final scores were calculated. The results are shown in Table 2.

[0025] Table 1 Scoring Criteria

[0026] Table 2. Final scores of concentrates in each group after 7 days of storage.

[0027] Table 2 shows that the concentrated juice prepared by the method of the present invention (Examples 1 to 3) not only retains its flavor and aroma well, but also improves its stability. The results of Example 3 and Comparative Examples 1 and 2 show that without prior aroma recovery before backfilling, or without encapsulation after aroma recovery before direct backfilling, not only is aroma easily lost and flavor diluted, but stability also deteriorates, leading to sedimentation and stratification. The results of Example 3 and Comparative Examples 3, 4, and 5 show that the encapsulation material for aroma substances, the size of aroma particles, and the order in which aroma particles and high-lipid pectin are mixed all have a significant impact on the quality of the concentrated juice, especially on its stability. Only by using β-cyclodextrin as the encapsulation material and preparing aroma particles with a particle size of less than 1 μm, and by first adding high-lipid pectin and then adding aroma particles for homogenization, can a concentrated juice with high stability be obtained.

[0028] Physical stability test: To further illustrate how the method of the present invention can improve the physical stability of passion fruit concentrate, the applicant conducted the following experiments: One bottle of concentrated juice from each example and each comparative example was placed on a table at room temperature (20±5℃) and allowed to stand. The presence of stratification, rings, or flocculent matter was observed on days 0, 7, 15, and 30. The results are shown in Table 3. Table 3 Physical stability of each group

[0029] The table above shows that the concentrated juice obtained by this invention has high physical stability.

[0030] Chemical stability test: To further illustrate how the method of the present invention can improve the chemical stability of passion fruit concentrate, the applicant conducted the following experiments: After 7 days of accelerated testing at 37℃, compared with the data from day 0, the pH value changed from 3.62 to 3.58 (change < 0.1), and the acidity remained stable; the sugar content changed from 11.2°Brix to 11.0°Brix (change < 0.2), and there was no obvious fermentation consumption of sugar.

[0031] The flavor of the juice will not become significantly rancid or diluted within its shelf life.

[0032] One bottle of concentrated juice from each example and comparative example was placed on a table at room temperature (20±5℃) and allowed to stand. Soluble solids, total acid, and browning degree (A420) were measured on days 0, 7, and 15. The results are shown in Tables 4-6. For soluble solids determination, the juice was shaken well, and 1-2 drops were added to the prism surface of a saccharimeter, and the value was read. Total acid was determined using a neutralization titration method. For browning degree determination, the supernatant was collected after centrifugation of the juice, and the absorbance value (A420) was measured at 420 nm. This value represents the degree of browning; a higher value indicates a higher degree of browning.

[0033] Table 4. Changes in soluble solids in each group (ºBrix)

[0034] Table 5. Changes in total acidity in each group (g / 100mL)

[0035] Table 6. Changes in browning degree (A420) for each group

[0036] Tables 4 to 6 above show that the concentrated juice obtained by the method of the present invention (Examples 1 to 3) exhibits small variations in soluble solids and total acid content. The product maintains a sweet and sour balance within 15 days, browning occurs slowly, and there is no significant change in color, demonstrating good chemical stability. The results of Example 3 and Comparative Examples 1 and 2 show that without prior aroma recovery before backfilling, or without encapsulation after aroma recovery before direct backfilling, not only is aroma easily lost, but the soluble solids and total acid content also change significantly, the taste becomes noticeably weaker, the degree of browning is higher, and chemical stability is poor.

[0037] The results from Example 3 and Comparative Examples 3, 4, and 5 show that the encapsulating material of aroma substances, the size of aroma particles, and the order in which aroma particles and high-fat pectin are mixed have little effect on the taste and browning degree of the concentrated juice, but have a greater effect on stability.

[0038] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing a passion fruit flavor concentrate, characterized in that, Includes the following steps: (1) Raw material pretreatment: Select mature and fresh passion fruit without mechanical damage or pests and diseases for cleaning and disinfection; (2) Juicing: The cleaned and disinfected passion fruit is cold-pressed at low temperature under nitrogen protection, filtered, and a compound antioxidant is added and mixed to obtain passion fruit juice. (3) Aroma recovery: The passion fruit juice is placed in a falling film evaporator, and after preheating, vacuum degassing, heating evaporation and condensation, the aroma recovery liquid and the deodorized juice are collected separately and stored at 4-10℃ for later use. (4) Aroma encapsulation: First, add β-cyclodextrin to water at 50-60℃ and stir until completely dissolved, and continue stirring until the temperature drops to 40-45℃ to obtain β-cyclodextrin solution; slowly add the aroma recovery solution dropwise to the β-cyclodextrin solution while stirring vigorously for 1-2 hours, cool naturally to room temperature, refrigerate at 4-8℃ for 12-24 hours, centrifuge, collect the precipitate, dry at 40-45℃, grind, and obtain aroma particles; (5) Concentration: The deodorized juice is concentrated under low temperature vacuum until the soluble solids content is ≥60% to obtain deodorized concentrated juice; (6) Backfilling and flavor enhancement: First, mix the deodorized concentrated juice with 0.1%-0.5% of the total amount of high ester pectin in the deodorized concentrated juice, and then shear at high speed to form a uniform and delicate slurry; then add 1-3% of the weight of the slurry of aroma particles to the slurry, and homogenize to obtain flavor enhancement concentrated juice; (7) Sterilization and filling: The flavor-enhancing concentrated juice is pasteurized and filled to obtain the passion fruit flavor concentrate.

2. The method for preparing a passion fruit flavor concentrate according to claim 1, characterized in that, In step (1), the cleaning and disinfection involves rinsing with running water and then soaking in 4-6 ppm ozone water for 1-2 minutes for disinfection.

3. The method for preparing a passion fruit flavor concentrate according to claim 1, characterized in that, In step (2), the temperature of the low-temperature cold pressing is 5-15℃.

4. The method for preparing a passion fruit flavor concentrate according to claim 1, characterized in that, In step (2), the composite antioxidant is a mixture of glucose oxidase and sodium isoascorbate in a mass ratio of 1:(30-50), and the amount of the composite antioxidant added is 0.05-0.1% of the weight of the passion fruit juice.

5. The method for preparing a passion fruit flavor concentrate according to claim 1, characterized in that, In step (3), the preheating temperature is 35-45℃; the vacuum degassing is to reduce the absolute pressure in the falling film evaporator to 4-8 kPa; the heating temperature for heating and evaporation is 30-50℃; and the condensation temperature is -5℃ to 5℃.

6. The method for preparing a passion fruit flavor concentrate according to claim 1, characterized in that, In step (4), the weight ratio of β-cyclodextrin to water is 1:(6-8); the mass ratio of aroma recovery liquid to β-cyclodextrin liquid is 1:(50-60).

7. The method for preparing a passion fruit flavor concentrate according to claim 1, characterized in that, In step (4), the particle size of the aroma particles is less than 1 μm.

8. The method for preparing a passion fruit flavor concentrate according to claim 1, characterized in that, In step (5), the temperature of the low-temperature vacuum concentration is 40-45℃ and the absolute pressure is 6-8 kPa.

9. A passion fruit flavor concentrate prepared by the preparation method according to any one of claims 1 to 8.

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