Method for preparing low-viscosity red jujube thick pulp through dielectric barrier discharge plasma in cooperation with ultrahigh-pressure microjet

Abstract

The invention provides a method for preparing low-viscosity red jujube thick pulp through dielectric barrier discharge plasma in cooperation with ultrahigh-pressure microjet. The preparation method comprises the following steps: putting red jujube thick pulp A with the mass percentage of 30-50% into a sample tank of a dielectric barrier discharge plasma device, adjusting the distance between upper and lower discharge electrode plates of the sample tank to be 2-8cm, treating for 2-5min under the conditions that the discharge voltage is 30-100V and the discharge current is 2-5A to obtain red jujube thick pulp B, treating the treated red jujube thick pulp B for 2-3 times under the conditions that the pressure is 100-600MPa and the temperature is 20-50 DEG C by adopting ultrahigh-pressure microjet, and finally obtaining the red jujube thick pulp. The low-viscosity thick red date pulp C is obtained. The method for preparing the low-viscosity thick red date pulp is simple in process operation, high in viscosity reduction efficiency and suitable for preparing the low-viscosity thick red date pulp.

Description

Technical Field

[0001] The invention belongs to the field of food, and specifically relates to a method for preparing low-viscosity red date slurry by using dielectric barrier discharge plasma in coordination with ultra-high pressure micro jet. Background Art

[0002] Red dates are rich in nutrients and have the effects of anti-oxidation and enhancing immunity. Red date concentrate is a concentrated juice product obtained by extracting and concentrating red dates with water. It has a strong flavor and rich nutrition, and is very popular in the market.

[0003] CN 104687175 A discloses an emulsified red date slurry, which is made of the following raw materials in parts by weight: 75-80 parts of red date slurry, 12-15 parts of health edible oil, 3-5 parts of lycopene, and 3-5 parts of lutein. The preparation method is as follows: after red dates are soaked in hot water, they are pulped, squeezed, centrifuged, and the supernatant is collected, and the supernatant is vacuumed to obtain red date slurry; lycopene, lutein and health edible oil are heated to 60-80°C, stirred evenly, and then subjected to colloid milling, and then added to the red date slurry, stirred evenly, subjected to colloid milling, heated to 75-80°C, and subjected to 100-300MPa high-pressure microfluidization treatment, and aseptically filled to obtain the final product. Lycopene and lutein are used as additives in the jujube slurry of the present invention, and the synergistic effect of the three is exerted through reasonable proportioning, and the natural emulsification effect of red date polysaccharides is utilized, and no emulsifier needs to be added, the process is simple, and the product quality is high.

[0004] CN 106135984 A discloses a production process of red date concentrated pulp, which comprises extracting red dates at least twice, combining the filtrates of the at least two extractions for concentration, and subjecting the concentrate obtained by the concentration to enzymolysis with saccharifying enzyme. The red date concentrated pulp is natural, pure and healthy, does not contain sugar, preservatives and other chemical additives, and has a mellow and fragrant taste.

[0005] However, red date pulp is rich in sugar compounds and has high viscosity. The high viscosity limits its processing and application. Therefore, researchers continue to study methods to reduce the viscosity of red date pulp. The Jinan Fruit Research Institute of the China National Federation of Supply and Marketing Cooperatives uses pulp enzyme hydrolysis technology to produce red date pulp. By comparing and selecting pulp enzymes, the viscosity of the date pulp is reduced (China Fruit and Vegetables, 2016, 36 (12): 8-12). However, this method is not very efficient in reducing viscosity. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a method for preparing low-viscosity red date concentrated paste by using dielectric barrier discharge plasma in conjunction with ultra-high pressure microjets. The method comprises the following steps: firstly, dielectric barrier discharge plasma is used to destroy viscous substances such as polysaccharides in the jujube paste, and then the ultra-high pressure microjets are used in conjunction with the polysaccharide molecular weight to further reduce the molecular weight of the polysaccharides to prepare low-viscosity jujube paste. The jujube paste prepared by the present invention has low viscosity and is rich in nutrition.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma and ultrahigh pressure micro jet, comprising the following steps:

[0009] Red jujube slurry A was placed in a sample slot of a dielectric barrier discharge plasma device, the spacing between the upper and lower discharge electrode plates of the sample slot was adjusted, and red jujube slurry B was obtained by dielectric barrier discharge plasma treatment. The treated red jujube slurry B was treated by ultrahigh pressure microjet to obtain low-viscosity red jujube slurry C.

[0010] Furthermore, the preparation method of the red date concentrated pulp A is as follows: disease-free gray dates are selected, washed with clean water to remove surface impurities, extracted for 2 to 5 hours at a material-water mass ratio of 1:8 and a temperature of 100°C, centrifuged at a speed of 5000 r / min for 20 minutes after extraction, and the residue is removed. The extract is concentrated under a vacuum degree of 0.78 MPa to a juice soluble solid mass percentage of 30 to 50%, thereby obtaining red date concentrated pulp A.

[0011] Furthermore, the distance between the upper and lower discharge electrode plates of the sample tank is adjusted to 2 to 8 cm.

[0012] Furthermore, the discharge voltage of the dielectric barrier discharge plasma treatment is 30 to 100 V, the discharge current is 2 to 5 A, and the treatment time is 2 to 5 min.

[0013] Furthermore, the dielectric barrier discharge plasma treatment was performed under the conditions of a discharge voltage of 100 V and a discharge current of 3 A for 5 minutes.

[0014] Furthermore, the red date slurry B was treated 2 to 3 times by ultra-high pressure microfluidization at 100 to 600 MPa and 20 to 50° C. to obtain a red date slurry C with low viscosity.

[0015] Furthermore, the red date slurry B was treated twice by ultra-high pressure microfluidization at 400 MPa and 50° C. to obtain a red date slurry C with low viscosity.

[0016] Furthermore, the method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma and ultra-high pressure microjet of the present invention comprises the following steps: using 30-50% by mass of red date slurry A, placing it in a sample slot of a dielectric barrier discharge plasma device, adjusting the spacing between the upper and lower discharge electrode plates of the sample slot to 5 cm, treating it for 5 minutes under the conditions of a discharge voltage of 100 V and a discharge current of 3 A to obtain red date slurry B, treating the treated red date slurry B twice under the conditions of 400 MPa and 50°C using an ultra-high pressure microjet to obtain a low-viscosity red date slurry C.

[0017] The present invention also provides a low-viscosity red date slurry prepared by utilizing the dielectric barrier discharge plasma coordinated ultrahigh pressure micro jet method.

[0018] Furthermore, the viscosity of the low-viscosity red date slurry is 20 to 50 mL / g.

[0019] Compared with the prior art, the invention has the following beneficial effects: the previous enzymatic hydrolysis technology for pulp produced red date pulp. Due to the specificity of the enzyme, the pulp enzyme can only decompose part of the polysaccharide glycosidic bonds, and the viscosity reduction efficiency is low; the present invention firstly adopts plasma treatment to decompose and depolymerize the polysaccharide molecular chain to a limited extent; then, ultra-high pressure micro-jet is used for impact, cavitation and other effects to further break the depolymerized polysaccharide sugar chain, and the synergistic effect occurs, and the polysaccharide degradation efficiency and the degree of viscosity reduction of the jujube pulp are high. The present invention overcomes the shortcomings of the current low-viscosity red date concentrated pulp production method, and has the advantages of short time, high efficiency and simple process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 The viscosity of the products of the different treatment methods of the present invention;

[0022] Figure 2 The polysaccharide content of the products of the different treatment methods of the present invention;

[0023] Figure 3 The weight average molecular weight of the products of different treatment methods of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention, and those skilled in the art in this field can make some non-essential improvements and adjustments based on the content of the above invention.

[0025] Example 1

[0026] A method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma and ultrahigh pressure micro jet, comprising the following steps:

[0027] (1) 40% by weight of red date concentrate A was placed in a sample tank of a dielectric barrier discharge plasma device, the distance between the upper and lower discharge electrode plates of the sample tank was adjusted to 5 cm, and the sample was treated for 5 minutes under the conditions of a discharge voltage of 100 V and a discharge current of 3 A to obtain a red date concentrate B.

[0028] (2) The treated red date slurry B was treated twice by ultrahigh pressure microfluidization at 400 MPa and 50° C. to obtain a low-viscosity red date slurry C with a viscosity of 20.2 mL / g.

[0029] Example 2: (Compared to Example 1, the discharge voltage is lower)

[0030] A method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma and ultrahigh pressure micro jet, comprising the following steps:

[0031] (1) A 40% by mass red date concentrate A was placed in a sample tank of a dielectric barrier discharge plasma device, the distance between the upper and lower discharge electrode plates of the sample tank was adjusted, and the sample was treated for 5 min at a discharge voltage of 50 V and a discharge current of 3 A to obtain a red date concentrate B.

[0032] (2) The treated red date slurry B was treated twice by ultrahigh pressure microfluidization at 400 MPa and 50° C. to obtain a low-viscosity red date slurry C with a viscosity of 32.5 mL / g.

[0033] Example 3: (Compared to Example 1, the ultra-high pressure micro jet pressure is low)

[0034] A method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma and ultrahigh pressure micro jet, comprising the following steps:

[0035] (1) Red jujube slurry A with a mass percentage of 40% was placed in a sample tank of a dielectric barrier discharge plasma device, the distance between the upper and lower discharge electrode plates of the sample tank was adjusted, and the sample was treated for 5 minutes under the conditions of a discharge voltage of 100 V and a discharge current of 3 A to obtain red jujube slurry B.

[0036] (2) The treated red date slurry B was treated twice by ultrahigh pressure microfluidization at 200 MPa and 50° C. to obtain a low-viscosity red date slurry C with a viscosity of 36.2 mL / g.

[0037] Example 4: (Compared to Example 1, the discharge voltage is low and the ultra-high pressure micro jet pressure is low)

[0038] A method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma and ultrahigh pressure micro jet, comprising the following steps:

[0039] (1) A 40% by mass red date concentrate A was placed in a sample tank of a dielectric barrier discharge plasma device, the distance between the upper and lower discharge electrode plates of the sample tank was adjusted, and the sample was treated for 5 min at a discharge voltage of 50 V and a discharge current of 3 A to obtain a red date concentrate B.

[0040] (2) The treated red date slurry B was treated twice by ultrahigh pressure microfluidization at 200 MPa and 50° C. to obtain a low-viscosity red date slurry C with a viscosity of 46.5 mL / g.

[0041] Comparative Example 1: Preparation of concentrated jujube pulp by direct extraction

[0042] 1. Select disease-free gray dates and wash them with clean water to remove surface impurities;

[0043] 2. Extraction: The cooking water ratio is 1:8 (m:m), the temperature is 100°C, and the time is 2 to 5 hours;

[0044] 3. After extraction, centrifuge at 5000r / min for 20min to remove the residue.

[0045] 3. Concentration: When the vacuum degree of the extract is 0.78 MPa, the soluble solid content of the concentrated juice reaches 30-50%.

[0046] Comparative Example 2: Preparation of Enzymatically Hydrolyzed Red Dates Suspension

[0047] 1. Select disease-free gray dates and wash them with clean water to remove surface impurities;

[0048] 2. Pre-cooking: The pre-cooking material-water ratio is 1:8, the temperature is 100℃, and the time is 15 minutes;

[0049] 3. Enzymatic hydrolysis and extraction: add pectinase-cellulase (mass ratio 1:1), enzyme dosage 25.0 mg / kg, enzymatic hydrolysis temperature 50°C, pH 4.0, enzymatic hydrolysis time 2.5 h.

[0050] 4. Inactivate enzyme: The extract is coarsely filtered and inactivated at 95°C for 15 min.

[0051] 5. Concentration: Under the condition of vacuum degree of 0.78MPa, the soluble solids of the concentrated juice reaches 30-50%.

[0052] Comparative Example 3: Preparation of low-viscosity red date slurry using only dielectric barrier discharge plasma

[0053] 40% by mass of red date concentrated pulp A was placed in a sample slot of a dielectric barrier discharge plasma device, the distance between the upper and lower discharge electrode plates of the sample slot was adjusted, and the sample was treated for 5 minutes under the conditions of a discharge voltage of 100V and a discharge current of 3A to obtain red date concentrated pulp B.

[0054] Comparative Example 4: Preparation of low-viscosity red date slurry using only ultrahigh pressure microfluidization

[0055] 40% by mass of red date concentrated pulp A was treated twice by ultra-high pressure microfluidization at 400 MPa and 50° C. to obtain red date concentrated pulp C with low viscosity.

[0056] Comparative experimental results

[0057] 1. Viscosity of products with different treatment methods

[0058] Using Ubbelohde viscometer, the viscosity of distilled water at 20℃ was used as the control, and the reduced viscosity of the products obtained by different methods was measured at 25℃. The results are as follows: Figure 1 :

[0059] From the above experiments, it can be seen that the viscosity of the red date slurry prepared by dielectric barrier discharge plasma and ultra-high pressure microjet is lower than that of the red date slurry prepared by dielectric barrier discharge plasma and ultra-high pressure microjet (P<0.05), and the viscosity of the red date slurry prepared by dielectric barrier discharge plasma and ultra-high pressure microjet is lower than that of the red date slurry prepared by comparative examples 1 and 2 (P<0.05). It shows that dielectric barrier discharge plasma and ultra-high pressure microjet can achieve a better viscosity reduction effect.

[0060] 2. Polysaccharide content of products treated by different methods

[0061] The polysaccharide content in 40% jujube pulp treated by different methods was compared. Figure 2 :

[0062] There was no significant difference in the polysaccharide content among the groups (P>0.05), indicating that dielectric barrier discharge plasma synergistic ultrahigh pressure microjet treatment, dielectric barrier discharge plasma, and ultrahigh pressure microjet treatment did not cause the cleavage of glycosidic bonds to generate monosaccharides, but only moderately degraded them, and they still existed in the form of polysaccharides.

[0063] 3. Comparison of weight average molecular weight of products treated by different methods

[0064] Comparison of weight average molecular weight of products treated by different methods Figure 3 .

[0065] From the above experiments, it can be seen that the weight average molecular weight of the red date slurry prepared by dielectric barrier discharge plasma and ultrahigh pressure microjet is lower than that of the red date slurry prepared by dielectric barrier discharge plasma and ultrahigh pressure microjet (P<0.05), and the weight average molecular weight of the red date slurry prepared by dielectric barrier discharge plasma and ultrahigh pressure microjet is lower than that of the red date slurry prepared by comparative example 1 and comparative example 2 (P<0.05). It shows that dielectric barrier discharge plasma and ultrahigh pressure microjet can appropriately reduce the molecular weight of high molecules such as polysaccharides in red date slurry, and its change trend is similar to the effect of different methods on viscosity.

[0066] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma and ultrahigh pressure micro jet, characterized in that The following steps are involved: Red jujube slurry A was placed in a sample slot of a dielectric barrier discharge plasma device, the spacing between the upper and lower discharge electrode plates of the sample slot was adjusted, and red jujube slurry B was obtained by dielectric barrier discharge plasma treatment. The treated red jujube slurry B was treated by ultrahigh pressure microjet to obtain low-viscosity red jujube slurry C.

2. The method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma in collaboration with ultrahigh pressure micro jet according to claim 1, characterized in that: The preparation method of the red date concentrated pulp A is as follows: disease-free gray dates are selected, surface impurities are removed by washing with clean water, extraction is performed for 2-5 hours at a material-water mass ratio of 1:8 and a temperature of 100°C, centrifugation is performed at a speed of 5000r / min for 20 minutes after extraction, residues are removed, and the extract is concentrated under a vacuum degree of 0.78 MPa to a juice soluble solid mass percentage of 30-50%, thereby obtaining the red date concentrated pulp A.

3. The method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma in collaboration with ultrahigh pressure micro jet according to claim 1, characterized in that: Adjust the distance between the upper and lower discharge electrode plates of the sample tank to 2~8cm.

4. The method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma in collaboration with ultrahigh pressure micro jet according to claim 1, characterized in that: The discharge voltage of dielectric barrier discharge plasma treatment is 30 ~ 100V, the discharge current is 2 ~ 5A, and the treatment time is 2 ~ 5min.

5. The method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma in collaboration with ultrahigh pressure micro jet according to claim 4, characterized in that: The dielectric barrier discharge plasma treatment was carried out at a discharge voltage of 100 V and a discharge current of 3 A for 5 minutes.

6. The method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma in combination with ultrahigh pressure micro jet according to claim 1, characterized in that: The red date slurry B was treated by ultrahigh pressure microfluidization at 100-600 MPa and 20-50℃ for 2-3 times to obtain the red date slurry C with low viscosity.

7. The method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma in combination with ultrahigh pressure micro jet according to claim 6, characterized in that: The red date slurry B was treated twice by ultra-high pressure microfluidization at 400 MPa and 50°C to obtain a red date slurry C with low viscosity.

8. The method for preparing low-viscosity red date slurry by dielectric barrier discharge plasma in combination with ultrahigh pressure micro jet according to claim 1, characterized in that: A red date slurry A with a mass percentage of 30 to 50% was placed in a sample tank of a dielectric barrier discharge plasma device, and the spacing between the upper and lower discharge electrode plates of the sample tank was adjusted to 5 cm. The slurry was treated for 5 minutes at a discharge voltage of 100 V and a discharge current of 3 A to obtain a red date slurry B. The treated red date slurry B was treated twice by ultra-high pressure microjet at 400 MPa and 50°C to obtain a low-viscosity red date slurry C.

9. A low-viscosity red date slurry prepared according to the method of any one of claims 1 to 8.

10. The low-viscosity red date slurry according to claim 9, characterized in that: The viscosity of the low-viscosity red date slurry is 20-50 mL / g.

Images