Method and equipment for improving quality and efficiency of lycium barbarum puree through slit tangential ultrasonic reinforcement

Abstract

The invention discloses a method and equipment for improving quality and efficiency of wolfberry puree through slit tangential ultrasonic reinforcement, and belongs to the technical field of food / agricultural product processing. The method comprises the following steps: by taking Chinese wolfberry primary pulp as a raw material, pumping the Chinese wolfberry primary pulp into a slit-shaped divergent ultrasonic treatment cavity, controlling ultrasonic power, synchronizing dual-frequency combination, flowing speed in the slit cavity, circulating accumulated ultrasonic time in the cavity, micronizing, homogenizing, degassing, sterilizing and the like, thereby obtaining the ultrasonic enhanced quality-improving and efficiency-improving Chinese wolfberry primary pulp. The pulp yield, lycium barbarum polysaccharide, lycium barbarum protein, polyphenol, flavonoid substances and the dissolution amount of carotenoid of the obtained lycium barbarum primary pulp are improved to different extents, and the antioxidant activity of the polysaccharide and the protein in the lycium barbarum primary pulp is enhanced. The slit ultrasonic enhanced Chinese wolfberry primary pulp can achieve the effect of improving quality and efficiency. The technology is simple, production operation is easy, and the utilization depth and breadth of the wolfberry primary pulp can be enlarged.

Description

Technical Field

[0001] The invention belongs to the technical field of processing food / agricultural products and their by-products, and relates to a method and equipment for improving the quality and efficiency of wolfberry pulp by strengthening slit tangential ultrasound. Background Art

[0002] Lycium chinense Mill. is the mature fruit of the Lycium barbarum plant of the Solanaceae family. It is rich in various nutrients such as protein, carbohydrates, vitamins, and various functional ingredients such as polysaccharides, carotenoids, and polyphenols. It has multiple functions such as regulating immunity, anti-oxidation, lowering blood sugar, and lowering blood lipids. It is an economic fruit with a long history of both medicinal and edible uses. The planting area in my country has exceeded 3.5 million mu. Lycium barbarum puree is one of the main beverage forms of fresh wolfberry processing. It can be used as puree or ingredients for beverages, alcoholic beverages, functional foods, etc. to meet the diversified market needs, and its development space is huge. The existing wolfberry pressing and pulping processing technology in my country has major problems such as low pulping rate, limited dissolution of nutrients and functional ingredients, and poor quality stability, which seriously affect the depth and breadth of the development of deep-level high-quality wolfberry puree. Therefore, the development of quality improvement and efficiency enhancement technology for wolfberry puree processing is an inevitable trend for the sustainable and healthy development of the wolfberry beverage industry.

[0003] Domestic and foreign scholars have used ultrasonic multi-physics fields to strengthen food processing. There have been many reports on increasing the yield of effective ingredients, modifying structures to improve efficacy and activity, and improving processing efficiency, and the results are remarkable. These results fully confirm the unique advantages of ultrasound in strengthening the dissolution of polysaccharides and proteins, modifying structures to improve their functional properties, and also show the broad prospects of ultrasound in the large-scale preparation of effective ingredients and nutrients. Ultrasound has been reported on the effects of polyphenols, Vc and other active substances, sensory quality, enzymes, clarification, homogenization and sterilization of freshly squeezed fruit pulp, which fully confirms the application potential of ultrasound in fruit and vegetable processing. According to new research, the ultrasonic equipment used for the extraction, pulping, clarification, homogenization and sterilization of wolfberry effective ingredients is a focused ultrasound with a probe transducer. This generator is difficult to break through the industrial amplification energy limit, and has many disadvantages such as uneven sound field, easy to generate reverberation field and cavitation. Wolfberry pulp is a viscous fluid, and the focused ultrasonic sound field cannot meet the uniform enhanced mass transfer characteristics of the sound field, resulting in incomplete dissolution of most nutrients and effective ingredients or local over-hydrolysis, affecting the quality of the pulp product. Based on this, this patent was invented, which designs and utilizes the propagation direction of the ultrasonic sound field arranged perpendicular to the flow direction of the viscous pulp to form a tangential flow to enhance mass transfer, and uses two vibration plates arranged face to face to form a slit-shaped reaction chamber, which makes up for the many disadvantages of energy-focused ultrasound, and at the same time solves the problem of divergent ultrasonic sound energy not being concentrated, overcomes the appearance of standing waves, and breaks through the technical difficulties of industrial amplification. The multi-physical field formed by this equipment is more suitable for mass transfer enhancement of thick pulp fluids, but there has been no research and application of processing for fruit and vegetable pulping at home and abroad. Summary of the invention

[0004] This project aims to address the technical bottlenecks of low quality, poor stability, and large production losses caused by the lack of efficient processing technology for wolfberry pulping in my country, which seriously restricts the depth and breadth of the development of high-quality products of wolfberry pulp. The project aims to improve the quality and efficiency of wolfberry pulp, and based on the characteristics of viscous fluids, establish a new technology for improving the quality and efficiency of wolfberry pulping by strengthening the countercurrent tangential ultrasonic field, so as to improve the efficacy and quality stability of wolfberry pulp, and promote the development of my country's wolfberry beverage industry towards a healthy and refined level.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical scheme:

[0006] A method for improving the quality and efficiency of wolfberry puree by slit tangential ultrasound enhancement is carried out according to the following steps:

[0007] (1) Raw material pretreatment: fresh wolfberry fruit, remove damaged and immature fruits, soak in pure water with a mass volume ratio of 1:5 (kg:L) at room temperature for 15 minutes, then bubble rinse for 20 minutes, clean, and set aside.

[0008] (2) Pulping: The cleaned fresh wolfberry fruit is pulped in a pulping machine at room temperature for 10 min (power 250 W, 22000 r / min, intermittent ratio 1 min / 2 min) to obtain wolfberry pulp.

[0009] (3) Ultrasonic strengthening of wolfberry puree: The wolfberry puree prepared in step (2) is pumped into a slit-shaped ultrasonic treatment chamber, the ultrasonic power is controlled to be 200-300 W, the ultrasonic frequency combination is 25-28 kHz, 28-33 kHz, 28-40 kHz, the flow rate of the puree in the slit chamber is controlled to be 0.5-1 m / s, the cumulative circulation time in the chamber is 20-40 min, the ultrasonic intermittent ratio is 5s / 2s, and the seed skin is separated by filtration to obtain ultrasonically strengthened wolfberry puree.

[0010] (4) Micronization of wolfberry puree: The wolfberry puree in step (3) is micronized by a colloid mill to obtain a homogeneity of more than 90%.

[0011] (5) Homogenization: The micronized pulp obtained in step (4) is subjected to high-pressure homogenization at 28 MPa and a preheating temperature of 60° C. for 30 min to obtain a uniform and viscous pulp.

[0012] (6) Degassing: The raw pulp from step (5) is put into a degasser (degassing at -0.05 MPa for 20 min) to remove air (oxygen) from the liquid, inhibit the oxidation of browning, pigments, vitamins, and other components, and prevent quality degradation.

[0013] (7) Sterilization: The degassed slurry from step (6) was sterilized at 85°C for 20 min.

[0014] (8) Aseptic filling: obtain wolfberry puree product with enhanced quality and efficacy by countercurrent tangential ultrasound.

[0015] This project uses a slit-shaped ultrasonic equipment. The ultrasonic processing chamber of the equipment is slit-shaped, that is, the ultrasonic vibration plates are arranged face to face to form a slit cavity. The sound field of this slit cavity is evenly distributed and concentrated; the slurry flow direction is perpendicular to the sound field generation direction. This countercurrent tangential ultrasound has a good effect on enhancing mass transfer and promoting nutrient dissolution; it is equipped with 4 generators with different frequencies, and the frequency and combination can be adjusted according to needs, which is suitable for the enhanced treatment of different raw material slurries; the processing chamber is separately configured from the wolfberry slurry storage tank, and uses external circulation to enter the slit cavity, which is not limited by the slurry (reaction liquid) capacity.

[0016] The wolfberry slurry in the slurry storage tank is controlled by a peristaltic pump to flow through the liquid inlet of the slit ultrasonic equipment and pumped into the slit ultrasonic treatment cavity. The ultrasonic parameters are adjusted by a PLC controller, ultrasonic transducers and generators of different frequencies, so that the slurry is ultrasonically enhanced treated in the slit cavity for a certain period of time to obtain ultrasonically enhanced wolfberry slurry.

[0017] Beneficial effects of the present invention:

[0018] (1) The ultrasonic vibration plates of the ultrasonic device used in the present invention are arranged face to face to form a slit-shaped tangential ultrasonic field. The sound field is concentrated and evenly distributed. The external circulation is not limited by the capacity of the ultrasonic cavity, and is particularly suitable for the enhanced mass transfer of viscous fluids such as wolfberry pulp.

[0019] (2) The present invention can effectively promote the dissolution of nutrients and beneficial ingredients in wolfberry by controlling the slit-shaped ultrasonic parameters, and can also modify wolfberry polysaccharides and protein macromolecules to improve their functional properties and enhance their antioxidant activity, thereby achieving the effect of improving the quality and efficacy of wolfberry puree.

[0020] (3) The present invention provides a new ultrasonic method for enhancing the quality and efficiency of viscous fluid ultrasonic mass transfer, which is of great significance for the processing of fruit and vegetable beverages and improving the processing depth and breadth of their products. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of the slit-shaped ultrasonic processing equipment of the present invention, wherein 1 is a slurry storage tank, 2 is a peristaltic pump, 3 is a liquid inlet, 4 is a slit ultrasonic processing cavity, 5 is an ultrasonic vibration plate, 6 is an ultrasonic transducer, 7 is an ultrasonic transducer housing, 8 is a liquid outlet, 9 is a PLC controller, and 10 is an ultrasonic generator of different frequencies. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] The technical scheme of the present invention is further described below in conjunction with specific embodiments. The juice yield of the present invention is determined by the GB7101-2015 method, the total polysaccharide dissolution amount of wolfberry is determined by the phenol-sulfuric acid method, the reducing sugar content is determined by the GB5009.7-2016 method, the polysaccharide content is determined by the difference subtraction method (total polysaccharide minus reducing sugar content), the protein content is determined by the GB 5009.5-2016 method, the polyphenol content is determined by the Folin-phenol method, the flavonoid content is determined by the GB / T 30359-2013 method, and the carotenoid content is determined by the GB 5009.83-2016 method; the uronic acid content of the wolfberry raw pulp polysaccharide is determined by the m-hydroxybiphenyl method, and the sulfate content is determined by the gelatin barium chloride method. The molecular weight of Lycium barbarum polysaccharide was determined by size exclusion chromatography combined with multi-angle laser scattering and differential detection (SEC-MALLS-RI), and the subunit composition of the protein was determined by gel electrophoresis. The in vitro antioxidant activity of polysaccharides and proteins was determined by DPPH· and ABTS + The removal rate adopts GB / T 39100-2020 method, O2 - · Clearance was determined using the pyrogallol method.

[0025] The structural model diagram of the slit-shaped divergent ultrasonic device used in the present invention is as follows: Figure 1 As shown. The ultrasonic treatment chamber of the device is slit-shaped 4, that is, the ultrasonic vibration plates 5 are arranged face to face to form a slit chamber 4. The sound field of this slit chamber is evenly distributed and concentrated; the slurry flow direction is perpendicular to the sound field generation direction, and this countercurrent tangential ultrasonic field has a better effect of enhancing mass transfer and promoting nutrient dissolution; it is equipped with 4 generators with different frequencies 9, and the frequency and combination can be adjusted according to needs, which is suitable for the enhanced treatment of different raw material slurries; the treatment chamber is separately configured from the wolfberry slurry storage tank 1, and enters the slit chamber in an external circulation manner, which is not limited by the slurry (reaction liquid) capacity.

[0026] Example 1

[0027] 1 kg of fresh wolfberry is taken, damaged and immature fruits are removed, the wolfberry is soaked in 5 L of pure water at room temperature for 15 min, the wolfberry is rinsed with bubbling for 20 min, and the wolfberry pulp is fully pulped for 10 min by a 250 W pulping machine (22000 r / min, intermittent ratio of 1 min / 2 min). The wolfberry pulp is pumped into a slit-shaped ultrasonic treatment chamber, the ultrasonic power is controlled to be 200 W, the ultrasonic frequency combination is 25-28 kHz, the flow rate of the pulp in the slit chamber is controlled to be 0.5 m / s, the cumulative circulation time in the chamber is 20 min, the ultrasonic intermittent ratio is 5 s / 2 s, the seed skin is separated by filtration, and the ultrasonic enhanced wolfberry pulp is obtained; the wolfberry pulp is micronized into 50 microns by a colloid mill, and the homogeneity reaches more than 90%; after being homogenized at 28 MPa and 60° C. for 30 min, it is degassed at -0.05 MPa for 20 min and sterilized at 85° C. for 20 min to obtain the wolfberry pulp product.

[0028] Example 2

[0029] The pretreatment of fresh wolfberry was the same as in Example 1, the ultrasonic power was controlled to be 300 W, the ultrasonic frequency combination was 28-40 kHz, the flow rate of the puree in the slit cavity was controlled to be 1 m / s, the cumulative time in the cavity was 40 min, the ultrasonic intermittent ratio was 5s / 2s, and the subsequent treatment was the same as in Example 1 to obtain a wolfberry puree product.

[0030] Example 3

[0031] The fresh wolfberry fruit was pretreated in the same manner as in Example 1, the ultrasonic power was controlled to be 250 W, the ultrasonic frequency combination was 28-33 kHz, the flow rate of the puree in the slit cavity was controlled to be 0.75 m / s, the cumulative time in the cavity was 30 min, the ultrasonic intermittent ratio was 5 s / 2 s, and the subsequent treatment was the same as in Example 1 to obtain the wolfberry puree product.

[0032] Comparative Example 1

[0033] The traditional method is used to prepare wolfberry puree. Except for not applying ultrasound, the remaining steps are the same as those in Example 1 to obtain a non-ultrasonic wolfberry puree product.

[0034] Comparative Example 2

[0035] Focused ultrasound enhanced wolfberry pulping. Fresh wolfberry was pretreated as in Example 1, with the ultrasonic power at 300 W, the ultrasonic frequency at 33 kHz, the ultrasonic cumulative time at 30 min, and the ultrasonic intermittent ratio at 5 s / 2 s. The subsequent treatment was the same as in Example 1 to obtain a focused ultrasonic wolfberry pulp product.

[0036] Table 1 is a comparative table of the dissolution and content of nutrients and functional ingredients in the wolfberry puree products of various embodiments. As can be seen from the table. The main nutrients and functional ingredients in the puree products of Examples 1-3 and Comparative Example 2 are higher than those of Comparative Example 1 without any ultrasound, especially Example 3, whose juice yield is 3.04% higher than that of the Comparative Example. Not only the dissolution rate of polysaccharides is increased (increased by 36.98%-84.59%), but also the content of total polysaccharides (increased by 30.78%-63.40%), polyphenols (increased by 72.97%), flavonoids (increased by 43.49%), soluble proteins (increased by 71.12%) and carotenoids (increased by 22.73%) in wolfberry puree is increased. In addition, ultrasonic treatment significantly reduced the molecular weight of wolfberry puree polysaccharides, and the contents of uronic acid and sulfate in polysaccharides increased by 22.5% and 58.3%, respectively; the particle size and polydispersity index of the protein were reduced, and the hydrophobic group increased, but it had no effect on the subunit composition of the protein (Table 2). This plays an important role in the biological activity of polysaccharides. As can be seen from Table 3, the IC50 values ​​of the scavenging rates of the polysaccharides and proteins in the wolfberry puree products of Examples 1-3 for the three free radicals are lower than those in Comparative Examples 1 and 2. The lower the IC50 value, the stronger its antioxidant activity. The above results show that ultrasonic enhanced treatment helps to promote the dissolution of nutrients and effective ingredients, and has great application value for improving the quality and efficiency of wolfberry puree. It has been proved that slit-shaped divergent ultrasound can effectively increase the dissolution amount of wolfberry polysaccharides and achieve the effect of "quality improvement".

[0037] Table 1 Comparison of dissolution and content of nutrients and effective components of wolfberry puree enhanced by ultrasound

[0038]

[0039] Table 2 Comparison of molecular weight and structural characteristics of polysaccharides and proteins in wolfberry pulp enhanced by ultrasound

[0040]

[0041] Table 3 Comparison of antioxidant activity of polysaccharides and proteins in wolfberry puree enhanced by ultrasound

[0042]

[0043] The present invention has been described by what are currently considered to be the most preferred and practical embodiments, and it should be understood that the present invention is not limited to the disclosed embodiments. On the contrary, its purpose is to cover various modifications and equivalent arrangements within the spirit and scope of the appended claims, and its scope is to be given the broadest interpretation to include all such modifications and equivalent structures permitted under the law.

Claims

1. A method for improving the quality and efficiency of wolfberry puree by slit tangential ultrasound, characterized in that Follow these steps: (1) Raw material pretreatment: fresh wolfberry fruits, remove damaged and immature fruits, soak in pure water with a mass-to-volume ratio of 1:5 (kg:L) at room temperature for 15 minutes, then rinse with bubbling for 20 minutes, clean and set aside; (2) beating: beating the cleaned fresh wolfberry fruits in a beating machine at room temperature for 10 minutes to obtain wolfberry pulp; (3) Ultrasonic strengthening of wolfberry puree: pumping the wolfberry puree from step (2) into a slit-shaped ultrasonic treatment chamber, controlling the puree to flow in the slit chamber, and filtering to separate the seed coat to obtain ultrasonically strengthened wolfberry puree; (4) Micronizing wolfberry puree: The wolfberry puree in step (3) is micronized by a colloid mill to obtain a homogeneity of more than 90%; (5) homogenizing: the micronized stock obtained in step (4) is subjected to high pressure homogenization to obtain a uniform and viscous stock; (6) Degassing: The raw pulp from step (5) is put into a degasser (degassing at -0.05 MPa for 20 min) to remove air (oxygen) from the liquid, inhibit the oxidation of browning, pigments, vitamins, and other components, and prevent quality degradation; (7) Sterilization: sterilize the degassed slurry from step (6) at 85° C. for 20 min; (8) Aseptic filling: obtain wolfberry puree product with enhanced quality and efficacy by countercurrent tangential ultrasound.

2. The method for improving the quality and efficiency of wolfberry puree by slit tangential ultrasound enhancement according to claim 1, characterized in that In step (2), the power of the pulping machine at room temperature is 250W, 22000r / min, and the intermittent ratio is 1min / 2min.

3. The method for improving the quality and efficiency of wolfberry puree by slit tangential ultrasound enhancement according to claim 1, characterized in that The ultrasonic power in step (3) is 200-300 W, the ultrasonic frequency combination is 25-28 kHz, 28-33 kHz or 28-40 kHz; the ultrasonic interval ratio is 5s / 2s.

4. The method for improving the quality and efficiency of wolfberry puree by slit tangential ultrasound enhancement according to claim 1, characterized in that In step (3), the flow rate of the slurry in the slit cavity is 0.5-1 m / s, and the cumulative circulation time in the cavity is 20-40 min.

5. The method for improving the quality and efficiency of wolfberry puree by slit tangential ultrasound enhancement according to claim 1, characterized in that The high-pressure homogenization conditions in step (5) are: homogenization for 30 minutes at 28 MPa and a preheating temperature of 60°C.

6. The method for improving the quality and efficiency of wolfberry puree by slit tangential ultrasound enhancement according to claim 1, characterized in that The degasser treatment condition in step (6) is degassing at -0.05 MPa for 20 minutes.

7. A slit-shaped ultrasonic device for ultrasonically strengthening wolfberry pulp to improve quality and increase narrowness. The ultrasonic processing chamber of the device is slit-shaped, that is, the ultrasonic vibration plates are arranged face to face to form a slit cavity. The sound field of this slit cavity is evenly distributed and concentrated; the slurry flow direction is perpendicular to the direction of the sound field generation, and this countercurrent tangential ultrasound has a good effect of enhancing mass transfer and promoting nutrient dissolution; it is equipped with 4 generators with different frequencies, and the frequency and combination can be adjusted according to needs, which is suitable for the enhanced treatment of different raw material slurries; the processing chamber is separately configured from the wolfberry slurry storage tank, and an external circulation method is used to enter the slit cavity, which is not limited by the slurry (reaction liquid) capacity; The wolfberry slurry in the slurry storage tank is controlled by a peristaltic pump to flow through the liquid inlet of the slit ultrasonic equipment and pumped into the slit ultrasonic treatment cavity. The ultrasonic parameters are adjusted by a PLC controller, ultrasonic transducers and generators of different frequencies, so that the slurry is ultrasonically enhanced treated in the slit cavity for a certain period of time to obtain ultrasonically enhanced wolfberry slurry.

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