Preparation method of anti-caking jujube powder

Abstract

The invention discloses a preparation method of anti-caking jujube powder, which comprises the following steps: step 1, denucleating red jujubes, and slicing to obtain red jujube slices; step 2, performing water bath ultrasonic-assisted enzymolysis on the red date slices to remove sugar; 3, performing enzyme deactivation, and filtering to take out red date slices; and 4, washing the red date slices with clear water, blow-drying the surface moisture, freezing at-35 to-30 DEG C for 12-14 hours, carrying out vacuum freeze-drying until the moisture mass fraction is 5-8%, soaking in a modified solution for 1.5-2 hours, filtering, taking out the red date slices, blow-drying the surface moisture, freezing at-50 to-45 DEG C for 12-14 hours, carrying out vacuum freeze-drying until the moisture mass fraction is 5-8%, and crushing into powder with the particle size of 0.5-2 mm to obtain the red date powder. Primary red date powder is obtained; and step five, adding 14-23% by weight of a composite additive into the primary red date powder, uniformly mixing, freezing at-85 to-80 DEG C for 10-12 hours, carrying out vacuum freeze drying until the water mass fraction is lower than 5%, and carrying out superfine grinding until the particle size is not greater than 50 microns, so as to obtain the anti-caking red date powder. The red date powder prepared by the method disclosed by the invention is low in sugar content and good in anti-caking effect.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural product processing, and in particular to a method for preparing anti-caking jujube powder. Background Art

[0002] Jujube is a plant of the genus Jujube of the family Rhamnaceae native to my country, and is widely planted in Shandong, Hebei, Xinjiang, Ningxia and other places. Jujube is sweet and sour, rich in flavor, rich in nutrients such as vitamins and minerals, as well as active functional components such as polysaccharides and flavonoids, and has high nutritional value. However, jujube is easy to lose water, soften, and become alcoholic after harvesting, and is not resistant to storage and transportation. Under the current situation of limited fresh food consumption, this greatly restricts the development of the jujube industry. Therefore, drying is the most important storage and processing method for jujube. Jujube powder is favored by young consumers because of its convenience in consumption and has broad market prospects. However, the excessive sugar content, especially monosaccharides, makes jujube powder easy to absorb moisture and agglomerate during storage, which seriously affects the stability of product quality. Therefore, the development of an anti-caking jujube powder is of great significance to the stability of jujube powder quality. Summary of the invention

[0003] The invention provides a method for preparing anti-caking jujube powder, which reduces the sugar content of the jujube powder and then sequentially treats the jujube powder with a modified solution and a composite auxiliary agent, thereby achieving the purpose of effectively reducing the water absorption rate of the jujube powder and improving the anti-caking effect of the jujube powder.

[0004] In order to achieve these purposes and other advantages according to the present invention, a method for preparing anti-caking jujube powder is provided, comprising the following steps: Step 1: Remove the core of the red dates and slice them to obtain red date slices; Step 2: Soak the red date slices in water at 20-30°C for 50-80 minutes, then add pectinase and stir evenly, and then ultrasonicate in a water bath for 50-80 minutes; Step 3: Heat the aqueous solution in step 2 to 90°C for 3-5 minutes to inactivate the enzyme, and filter out the red date slices; Step 4: Rinse the red date slices with clean water for 20 to 40 seconds, blow dry the surface moisture of the red date slices, freeze them at -35 to -30°C for 12 to 14 hours, and then freeze-dry them under vacuum until the moisture mass fraction is 5 to 8%, and then soak them in the modified solution for 1.5 to 2 hours to fully swell the red date slices, filter out the red date slices, blow dry the surface moisture, and then freeze them at -50 to -45°C for 12 to 14 hours, and then freeze-dry them under vacuum until the moisture mass fraction is 5 to 8%, and then grind them into powder with a particle size of 0.5 to 2 mm to obtain red date primary powder; Step 5: Add 14-23% by weight of the composite auxiliary agent to the red date powder, mix well, freeze at -85-80°C for 10-12 hours, and then freeze-dry in vacuum until the moisture content is less than 5%, and then ultrafine grind to a powder with a particle size of no more than 50 microns to obtain anti-caking date powder.

[0005] Preferably, in the method for preparing the anti-caking jujube powder, in step 2, the ratio of the red jujube slices to water is 1:50-55 g / mL.

[0006] Preferably, in the method for preparing the anti-caking jujube powder, in step 2, the amount of pectinase added is 0.5-0.8% of the weight of the red date slices, and the enzyme activity is not less than 10000 U / g.

[0007] Preferably, in the method for preparing the anti-caking jujube powder, in step 2, the ultrasonic frequency is 40 kHz.

[0008] Preferably, in the method for preparing the anti-caking jujube powder, in step 4, the modified solution is a solution prepared by mixing sodium chloride and tea water in a mass ratio of 3-5: 40-50.

[0009] Preferably, in the method for preparing the anti-caking jujube powder, the method for preparing the tea water is: taking 10g of tea leaves and putting them into 500g of water at 80-90°C and soaking them for 40-60min.

[0010] Preferably, in the method for preparing the anti-caking jujube powder, in step five, the composite auxiliary agent is a mixture of stevioside, whey protein, and Lactobacillus paracasei in a mass ratio of 0.5-1.5:10-18:4-5.

[0011] The preparation method of the composite auxiliary agent comprises the following steps: dissolving whey protein in water to prepare a whey protein solution with a mass fraction of 10-20%, adjusting the pH value of the whey protein solution to 6.5-7.5, adding stevioside, stirring to dissolve the stevioside in the solution, adding Lactobacillus paracasei, stirring, mixing evenly to prepare a mixed solution, subjecting the mixed solution to high-pressure homogenization, and spray drying to obtain the composite auxiliary agent.

[0012] Preferably, in the preparation method of the anti-caking jujube powder, in step five, the method of adding the composite auxiliary agent is: at 0-2°C, first add the composite auxiliary agent to 5-8 times its volume of water and stir and mix evenly into a slurry, and at the same time, add 3-4 times its volume of water to the primary red date powder and stir and mix evenly into a slurry, then mix the composite auxiliary agent slurry and the primary red date powder slurry evenly, concentrate under reduced pressure to 40-50% of the original solid weight, and then freeze and dry.

[0013] The invention also provides an anti-caking jujube powder, which is prepared by any of the above preparation methods.

[0014] The present invention at least includes the following beneficial effects: the present invention removes sugars from red dates by ultrasound-assisted enzymatic hydrolysis, preliminarily reduces the water absorption rate of red date powder, and then sequentially acts on the red date powder by a modified solution and a composite auxiliary agent, further reducing the water absorption rate of the red date powder, thereby effectively improving the anti-caking effect of the red date powder and improving the quality stability of the product; the stevioside in the composite auxiliary agent of the present invention can also increase the sweetness of the red date powder, so that the red date powder can reduce blood sugar while maintaining a good taste, and is suitable for a variety of people to take; the whey protein and Lactobacillus paracasei in the composite auxiliary agent of the present invention can also add more nutrients to the red date powder, making the red date powder more nutritious.

[0015] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can implement the invention with reference to the description.

[0017] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0018] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0019] Example 1 The preparation method of anti-caking jujube powder comprises the following steps: Step 1: Take Ruoqiang grey dates, mechanically remove the core, and cut into slices with a thickness of 3 mm to obtain red date slices; Step 2: Soak the red date slices in 20°C water for 50 minutes, then add pectinase and stir evenly, and then ultrasonicate in a water bath for 50 minutes; The ratio of red date slices to water is 1:50 g / mL, the amount of pectinase added is 0.5% of the weight of the red date slices, the enzyme activity is 10000 U / g, and the ultrasonic frequency is 40 kHz; Step 3: Heat the aqueous solution in step 2 to 90°C for 3 minutes to inactivate the enzyme, and filter out the red date slices; Step 4: Rinse the red date slices with clean water for 20 seconds, blow dry the surface moisture of the red date slices, freeze them at -35°C for 12 hours, and then freeze-dry them in a vacuum until the moisture mass fraction is 5%, and then soak them in a modified solution prepared by mixing sodium chloride and tea water in a mass ratio of 3:40 for 1.5 hours to fully swell the red date slices, filter out the red date slices, blow dry the surface moisture, and then freeze them at -50°C for 12 hours, and then freeze-dry them in a vacuum until the moisture mass fraction is 5%, and then grind them into powder with a particle size of 0.5 mm using a grinder to obtain red date primary powder; The preparation method of tea water is as follows: 10g of black tea is put into 500g of 80°C water and soaked for 40 minutes.

[0020] Step 5, at 0°C, take red date powder and composite auxiliary agent in a weight ratio of 100:14, first add 5 times the volume of the composite auxiliary agent into water and stir and mix evenly into slurry, at the same time, add 3 times the volume of the red date powder into water and stir and mix evenly into slurry, then mix the composite auxiliary agent slurry with the red date powder slurry and stir evenly, concentrate under reduced pressure to 40% of the original solid weight, freeze at -85°C for 10 hours, then freeze-dry in vacuum to a water mass fraction of 4.5%, and then ultrafine grind to a powder with a particle size of 50 microns to obtain anti-caking jujube powder; Among them, the composite auxiliary agent is a mixture of stevioside, whey protein, and Lactobacillus paracasei in a mass ratio of 0.5:10:4; the preparation method of the composite auxiliary agent is: dissolve the whey protein in water to prepare a whey protein solution with a mass fraction of 10%, and adjust the pH of the whey protein solution to 6.5, then add stevioside, stir to dissolve it in the solution, then add Lactobacillus paracasei, stir, mix evenly, and prepare a mixed solution, transfer the mixed solution to a high-pressure homogenizer, set the homogenization pressure to 150MPa, the homogenization times to 3 times, perform high-pressure homogenization treatment, and then spray-dry the homogenized mixed solution through a spray dryer to obtain a powdered composite auxiliary agent, the inlet air temperature of the spray dryer is 180°C, the outlet air temperature is 80°C, and the feed rate is 5mL / min.

[0021] Example 2 The preparation method of anti-caking jujube powder comprises the following steps: Step 1: Take Ruoqiang grey dates, mechanically remove the core, and cut into slices with a thickness of 3 mm to obtain red date slices; Step 2: Soak the red date slices in 25°C water for 65 minutes, then add pectinase and stir evenly, and then ultrasonicate in a water bath for 65 minutes; The ratio of red date slices to water is 1:53 g / mL, the amount of pectinase added is 0.5% of the weight of the red date slices, the enzyme activity is 12000 U / g, and the ultrasonic frequency is 40 kHz; Step 3, heating the aqueous solution in step 2 to 90°C for 4 minutes to inactivate the enzyme, and filtering out the red date slices; Step 4: Rinse the red date slices with clean water for 30 seconds, blow dry the surface moisture of the red date slices, freeze them at -32°C for 13 hours, and then freeze-dry them in a vacuum until the moisture mass fraction is 6%, and then soak them in a modified solution prepared by mixing sodium chloride and tea water in a mass ratio of 4:45 for 100 minutes to fully swell the red date slices, filter out the red date slices, blow dry the surface moisture, and then freeze them at -48°C for 13 hours, and then freeze-dry them in a vacuum until the moisture mass fraction is 6%, and then grind them into powder with a particle size of 1 mm using a grinder to obtain red date primary powder; The preparation method of tea water is as follows: 10g of green tea is put into 500g of 85°C water and soaked for 50 minutes.

[0022] Step 5, at 1°C, take the red date powder and the composite auxiliary agent in a weight ratio of 100:18, first add the composite auxiliary agent to 6 times its volume of water and stir and mix evenly to form a slurry, at the same time, add the red date powder to 4 times its volume of water and stir and mix evenly to form a slurry, then mix the composite auxiliary agent slurry with the red date powder slurry and stir evenly, concentrate under reduced pressure to 45% of the original solid weight, freeze at -83°C for 11 hours, then freeze-dry in vacuum to a moisture mass fraction of 4%, and then ultrafine grind to a powder with a particle size of 30 microns to obtain anti-caking jujube powder; Among them, the composite auxiliary agent is a mixture of stevioside, whey protein, and Lactobacillus paracasei in a mass ratio of 1:14:4.5; the preparation method of the composite auxiliary agent is: dissolve the whey protein in water to prepare a whey protein solution with a mass fraction of 15%, and adjust the pH of the whey protein solution to 7, then add stevioside, stir to dissolve it in the solution, then add Lactobacillus paracasei, stir, mix evenly, and prepare a mixed solution, transfer the mixed solution to a high-pressure homogenizer, set the homogenization pressure to 200MPa, the homogenization times to 4 times, perform high-pressure homogenization treatment, and then spray-dry the homogenized mixed solution through a spray dryer to obtain a powdered composite auxiliary agent, the inlet air temperature of the spray dryer is 190°C, the outlet air temperature is 90°C, and the feed rate is 8mL / min.

[0023] Example 3 The preparation method of anti-caking jujube powder comprises the following steps: Step 1: Take Ruoqiang grey dates, mechanically remove the core, and cut into slices with a thickness of 3 mm to obtain red date slices; Step 2: Soak the red date slices in 30°C water for 80 minutes, then add pectinase and stir evenly, and then ultrasonically bathe for 80 minutes; The ratio of red date slices to water is 1: 55 g / mL, the amount of pectinase added is 0.8% of the weight of the red date slices, the enzyme activity is 15000 U / g, and the ultrasonic frequency is 40 kHz; Step 3: Heat the aqueous solution in step 2 to 90°C for 5 minutes to inactivate the enzyme, and filter out the red date slices; Step 4: Rinse the red date slices with clean water for 40 seconds, blow dry the surface moisture of the red date slices, freeze them at -30°C for 14 hours, and then freeze-dry them in a vacuum until the moisture mass fraction is 8%, and then soak them in a modified solution prepared by mixing sodium chloride and tea water at a mass ratio of 5:50 for 2 hours to fully swell the red date slices, filter out the red date slices, blow dry the surface moisture, and then freeze them at -45°C for 14 hours, and then freeze-dry them in a vacuum until the moisture mass fraction is 8%, and then grind them into powder with a particle size of 2 mm using a grinder to obtain red date primary powder; The preparation method of tea water is as follows: 10g of Pu'er tea is put into 500g of 90°C water and soaked for 60 minutes.

[0024] Step 5, at 2°C, take the red date powder and the composite auxiliary agent at a weight ratio of 100:23, first add the composite auxiliary agent to 8 times the volume of water and stir and mix evenly to form a slurry, at the same time, add the red date powder to 4 times the volume of water and stir and mix evenly to form a slurry, then mix the composite auxiliary agent slurry with the red date powder slurry and stir evenly, concentrate under reduced pressure to 50% of the original solid weight, freeze at -80°C for 12 hours, then freeze-dry in vacuum to a moisture mass fraction of 3%, and then ultrafine grind to a powder with a particle size of 10 microns to obtain anti-caking jujube powder; Among them, the composite auxiliary agent is a mixture of stevioside, whey protein, and Lactobacillus paracasei in a mass ratio of 1.5: 18: 5; the preparation method of the composite auxiliary agent is: dissolve the whey protein in water to prepare a whey protein solution with a mass fraction of 20%, and adjust the pH of the whey protein solution to 7.5, then add stevioside, stir to dissolve it in the solution, then add Lactobacillus paracasei, stir, mix evenly, and prepare a mixed solution, transfer the mixed solution to a high-pressure homogenizer, set the homogenization pressure to 250MPa, the homogenization times to 5 times, perform high-pressure homogenization treatment, and then spray-dry the homogenized mixed solution through a spray dryer to obtain a powdered composite auxiliary agent, the inlet temperature of the spray dryer is 200℃, the outlet temperature is 100℃, and the feed rate is 10mL / min.

[0025] Comparative Example 1 Same as Example 2, except that: the red date slices were not soaked in the modified solution; That is, step four is: rinse the red date slices with clean water for 30 seconds, blow dry the surface moisture of the red date slices, freeze them at -32°C for 13 hours, and then freeze-dry them in vacuum until the moisture mass fraction is 6%, freeze them at -48°C for 13 hours, and then freeze-dry them in vacuum until the moisture mass fraction is 6%, and grind them into powder with a particle size of 1 mm to obtain red date primary powder.

[0026] Comparative Example 2 Same as Example 2, except that: no tea leaves are included in the modified solution; That is, step four is: rinse the red date slices with clean water for 30 seconds, blow dry the surface moisture of the red date slices, freeze them at -32°C for 13 hours, and then vacuum freeze-dry them to a moisture mass fraction of 6%, and then soak them in a modified solution prepared by mixing sodium chloride and water in a mass ratio of 4:45 for 100 minutes to allow the red date slices to fully swell, filter out the red date slices, blow dry the surface moisture, and then freeze them at -48°C for 13 hours, and then vacuum freeze-dry them to a moisture mass fraction of 6%, and crush them into powder with a particle size of 1 mm to obtain red date primary powder.

[0027] Comparative Example 3 Same as Example 2, except that: there is no sodium chloride in the modified solution; That is, step four is: rinse the red date slices with clean water for 30 seconds, blow dry the surface moisture of the red date slices, freeze them at -32°C for 13 hours, and then vacuum freeze-dry them to a moisture mass fraction of 6%, and then soak them in a modified solution composed of tea water for 100 minutes to allow the red date slices to fully swell, filter out the red date slices, blow dry the surface moisture, and then freeze them at -48°C for 13 hours, and then vacuum freeze-dry them to a moisture mass fraction of 6%, and crush them into powder with a particle size of 1 mm to obtain red date primary powder; wherein, the preparation method of tea water is: take 10g of green tea and soak it in 500g of 85°C water for 50min.

[0028] Comparative Example 4 Same as Example 2, except that: no composite auxiliary agent was added; That is, step five is: at 1°C, add 4 times the volume of water to the red date powder, stir and mix evenly into a slurry, then reduce the pressure and concentrate to 45% of the original solid weight, freeze it at -83°C for 11 hours, then vacuum freeze-dry it to a moisture content of 4%, and then ultrafine grind it to a powder with a particle size of 30 microns to obtain anti-caking jujube powder.

[0029] Comparative Example 5 Same as Example 2, except that: the composite auxiliary agent does not contain whey protein and Lactobacillus paracasei; That is, the preparation method of the composite auxiliary agent is as follows: dissolve stevioside in water to prepare a stevioside solution with a mass fraction of 1%, transfer the stevioside solution to a high-pressure homogenizer, set the homogenization pressure to 200 MPa, and the homogenization times to 4 times, perform high-pressure homogenization treatment, and then spray-dry the homogenized stevioside solution through a spray dryer to obtain a powdered composite auxiliary agent, the inlet temperature of the spray dryer is 190°C, the outlet temperature is 90°C, and the feed rate is 8 mL / min.

[0030] Comparative Example 6 Same as Example 2, except that: the composite auxiliary agent does not contain steviol glycosides and Lactobacillus paracasei; That is, the preparation method of the composite auxiliary agent is as follows: dissolve whey protein in water to prepare a whey protein solution with a mass fraction of 15%, transfer the whey protein solution to a high-pressure homogenizer, set the homogenization pressure to 200 MPa, and the homogenization times to 4 times, perform high-pressure homogenization treatment, and then spray-dry the homogenized whey protein solution through a spray dryer to obtain a powdered composite auxiliary agent, the inlet temperature of the spray dryer is 190°C, the outlet temperature is 90°C, and the feed rate is 8 mL / min.

[0031] Comparative Example 7 Same as Example 2, except that: the composite auxiliary agent does not contain stevioside and whey protein; That is, the preparation method of the composite auxiliary agent is as follows: adding an appropriate amount of water to Lactobacillus paracasei, stirring and mixing evenly to prepare a Lactobacillus paracasei solution with a mass fraction of 5%, transferring the Lactobacillus paracasei solution to a high-pressure homogenizer, setting the homogenization pressure to 200MPa, the homogenization times to 4 times, performing high-pressure homogenization treatment, and then spray-drying the homogenized Lactobacillus paracasei solution through a spray dryer to obtain a powdered composite auxiliary agent, the inlet air temperature of the spray dryer is 190°C, the outlet air temperature is 90°C, and the feed rate is 8mL / min.

[0032] Comparative Example 8 Same as Example 2, except that: the composite auxiliary agent does not contain Lactobacillus paracasei; That is, the preparation method of the composite auxiliary agent is as follows: whey protein is dissolved in water to prepare a whey protein solution with a mass fraction of 15%, and the pH of the whey protein solution is adjusted to 7, and then stevioside is added and stirred to dissolve it in the solution to prepare a mixed solution, and the mixed solution is transferred to a high-pressure homogenizer, the homogenization pressure is set to 200 MPa, the number of homogenizations is 4, and high-pressure homogenization treatment is performed, and then the homogenized mixed solution is spray-dried by a spray dryer to obtain a powdered composite auxiliary agent, the inlet temperature of the spray dryer is 190°C, the outlet temperature is 90°C, and the feed rate is 8mL / min.

[0033] Comparative Example 9 Same as Example 2, except that: there is no whey protein in the composite auxiliary agent; That is, the preparation method of the composite adjuvant is as follows: dissolve stevioside in water to prepare a stevioside solution with a mass fraction of 1%, then add Lactobacillus paracasei, stir, mix evenly, prepare a mixed solution, transfer the mixed solution to a high-pressure homogenizer, set the homogenization pressure to 200 MPa, and the homogenization times to 4 times, perform high-pressure homogenization treatment, and then spray-dry the homogenized mixed solution through a spray dryer to obtain a powdered composite adjuvant, the inlet temperature of the spray dryer is 190°C, the outlet temperature is 90°C, and the feed rate is 8 mL / min.

[0034] Comparative Example 10 Same as Example 2, except that: there is no stevioside in the composite auxiliary agent; That is, the preparation method of the composite auxiliary agent is as follows: whey protein is dissolved in water to prepare a whey protein solution with a mass fraction of 15%, and the pH of the whey protein solution is adjusted to 7, and then Lactobacillus paracasei is added, stirred, mixed evenly, and prepared into a mixed solution, and the mixed solution is transferred to a high-pressure homogenizer, the homogenization pressure is set to 200MPa, the homogenization times are 4 times, and high-pressure homogenization treatment is performed, and then the homogenized mixed solution is spray-dried by a spray dryer to obtain a powdered composite auxiliary agent, the inlet temperature of the spray dryer is 190°C, the outlet temperature is 90°C, and the feed rate is 8mL / min.

[0035] Comparative Example 11 Same as Example 2, except that: in step 5, the composite adjuvant is directly added to the red dates and then water is added to mix into a slurry; That is, step five is: at 1°C, take red date powder and composite auxiliary agent in a weight ratio of 100:18, mix the composite auxiliary agent with the red date powder, add 10 times the volume of water of the mixed powder, stir and mix evenly into a slurry, concentrate under reduced pressure to 45% of the original solid weight, freeze at -83°C for 11 hours, then freeze-dry in vacuum to a moisture content of 4%, and then ultrafine grind to a powder with a particle size of 30 microns to obtain anti-caking jujube powder; wherein the composite auxiliary agent is a mixture of stevioside, whey protein and Lactobacillus paracasei in a mass ratio of 1:14:4.5; the preparation method of the composite auxiliary agent is: Albumin was dissolved in water to prepare a whey protein solution with a mass fraction of 15%, and the pH of the whey protein solution was adjusted to 7, and then stevioside was added and stirred to dissolve in the solution, and then Lactobacillus paracasei was added and stirred to mix evenly to prepare a mixed solution, and the mixed solution was transferred to a high-pressure homogenizer, the homogenization pressure was set to 200 MPa, the homogenization times were 4 times, and high-pressure homogenization treatment was performed, and then the homogenized mixed solution was spray-dried by a spray dryer to obtain a powdered composite additive, the inlet air temperature of the spray dryer was 190°C, the outlet air temperature was 90°C, and the feed rate was 8 mL / min.

[0036] Comparative Example 12 Same as Example 2, except that pectinase is not added in step 2.

[0037] Comparative Example 13 Same as Example 2, except that: no ultrasound is performed in step 2.

[0038] Comparative Example 14 Same as Example 2, except that: no modified solution was used to soak the red date slices; and no composite auxiliary agent was added.

[0039] That is, step 4 is: rinse the red date slices with clean water for 30 seconds, blow dry the surface moisture of the red date slices, freeze them at -32°C for 13 hours, and then freeze-dry them in a vacuum until the moisture content is 6%, freeze them at -48°C for 13 hours, and then freeze-dry them in a vacuum until the moisture content is 6%, and grind them into powder with a particle size of 1 mm to obtain red date primary powder; Step five is: at 1°C, add 4 times the volume of water to the red date powder, stir and mix evenly into a slurry, then reduce the pressure and concentrate to 45% of the original solid weight, freeze at -83°C for 11 hours, then vacuum freeze-dry to a moisture content of 4%, and then ultrafine grind to a powder with a particle size of 30 microns to obtain anti-caking jujube powder.

[0040] Comparative Example 15 Same as Example 2, except that: no ultrasonic enzymatic desugaring operation; that is, no step 2 and step 3.

[0041] Comparative Example 16 Same as Example 2, except that: the preparation method of the composite auxiliary agent in step 5 is: directly stirring and mixing stevioside, whey protein, and Lactobacillus paracasei in a mass ratio of 1:14:4.5 to obtain the composite auxiliary agent.

[0042] Comparative Example 17 The preparation method of jujube powder comprises the following steps: Take Ruoqiang grey dates, mechanically remove the core and slice them to obtain red date slices, freeze the red date slices at -83°C for 11 hours, then vacuum freeze-dry them until the moisture mass fraction is 4%, and then ultrafine grind them into powder with a particle size of 30 microns to obtain red date powder.

[0043] The sugar content and moisture absorption rate of the red date powder obtained in the above embodiments and comparative examples were tested, and the test results were recorded in Table 1. The sweetness of each red date powder was manually tasted and judged, and the perception results were recorded in Table 1, wherein the sugar content was determined by high performance liquid chromatography, and the unit of sugar content was: mg / mL; the method for determining the moisture absorption rate was: accurately weigh 1g of red date powder in the inner chamber of a health dish, absorb 12mL of a saturated sodium chloride solution in the outer chamber, cover the frosted glass sheet coated with vaseline, and seal (relative humidity 75%). After precise weighing, place it at a constant temperature of 25±1℃ for 5 days, and weigh it at 6h, 12h, 24h, and 5d, respectively. The moisture absorption rate (%) = [(weight after moisture absorption-weight before moisture absorption) / weight before moisture absorption] × 100%.

[0044] By analyzing the data results in Table 1, comparing the test results of Examples 1 to 3 and Comparative Example 17, it can be seen that the red date powder prepared by the method of the present invention has a significantly lower sugar content than the original red date powder, wherein the glucose content is reduced by 57.91%, and the moisture absorption rate is significantly reduced, and the anti-caking effect is significantly enhanced; by comparing the test data of Comparative Examples 14, 15, and 17, it can be seen that the moisture absorption rate of the red date powder can be reduced by extracting sugar from the red date with the aid of enzymatic hydrolysis and ultrasound, or by using the modified solution and the composite auxiliary agent in the present application to act on the red date powder in sequence, thereby reducing the amount of agglomeration; on this basis, by comparing the test results of Example 2 and Comparative Examples 1 to 10, it can be seen that the modified solution and the composite auxiliary agent play a vital role in reducing the moisture absorption rate of the red date powder. Only after being treated with the modified solution and the composite auxiliary agent can the moisture absorption rate of the red date powder be significantly reduced. However, any changes in the components of the modified solution or the composite auxiliary agent cannot significantly reduce the moisture absorption rate of the jujube powder, which is obvious. However, the two components act on the red date powder in turn to reduce the water absorption performance of the red date powder; comparing the test data of comparative examples 12 and 13, it can be seen that although the desugaring effect of the red date powder is worse, due to the effect of the modified solution and the composite auxiliary agent, it is obvious that the moisture absorption rate is also reduced relative to the original red date powder; the moisture absorption rate of comparative example 11 is higher than that of embodiment 2, because the method of the present invention is not adopted in the process of adding the composite auxiliary agent, resulting in its failure to work; the moisture absorption rate of comparative example 16 is higher than that of embodiment 2, because the added composite auxiliary agent is not prepared according to the preparation method of the composite auxiliary agent of the present invention, resulting in the failure of each component to fully play a role; moreover, the steviol glycoside in the composite auxiliary agent can also increase the sweetness of the red date powder, so that it maintains a good taste, whey protein and Lactobacillus paracasei can add more nutrients to the red date powder, making it more nutritious, so the red date powder prepared by the present invention is not only nutritious and has a good taste, but also has excellent anti-caking effect and more stable quality.

[0045] The number of devices and processing scales described here are used to simplify the description of the present invention. Applications, modifications and variations of the present invention will be obvious to those skilled in the art.

[0046] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A method for preparing anti-caking jujube powder, characterized in that: The following steps are involved: Step 1: Remove the core of the red dates and slice them to obtain red date slices; Step 2: Soak the red date slices in water at 20-30°C for 50-80 minutes, then add pectinase and stir evenly, and then ultrasonicate in a water bath for 50-80 minutes; Step 3: Heat the aqueous solution in step 2 to 90°C for 3-5 minutes to inactivate the enzyme, and filter out the red date slices; Step 4: Rinse the red date slices with clean water for 20 to 40 seconds, blow dry the surface moisture of the red date slices, freeze them at -35 to -30°C for 12 to 14 hours, and then freeze-dry them under vacuum until the moisture mass fraction is 5 to 8%, and then soak them in the modified solution for 1.5 to 2 hours to fully swell the red date slices, filter out the red date slices, blow dry the surface moisture, and then freeze them at -50 to -45°C for 12 to 14 hours, and then freeze-dry them under vacuum until the moisture mass fraction is 5 to 8%, and then grind them into powder with a particle size of 0.5 to 2 mm to obtain red date primary powder; Step 5: Add 14-23% by weight of the composite auxiliary agent to the red date powder, mix well, freeze at -85-80°C for 10-12 hours, and then freeze-dry in vacuum until the moisture content is less than 5%, and then ultrafine grind to a powder with a particle size of no more than 50 microns to obtain anti-caking date powder.

2. The method for preparing the anti-caking jujube powder according to claim 1, characterized in that: In step 2, the ratio of the red date slices to water is 1:50-55 g / mL.

3. The method for preparing the anti-caking jujube powder according to claim 1, characterized in that: In step 2, the amount of pectinase added is 0.5-0.8% of the weight of the red date slices, and the enzyme activity is not less than 10000 U / g.

4. The method for preparing the anti-caking jujube powder according to claim 1, characterized in that: In step 2, the ultrasonic frequency is 40 kHz.

5. The method for preparing the anti-caking jujube powder according to claim 1, characterized in that: In step 4, the modified solution is a solution prepared by mixing sodium chloride and tea water in a mass ratio of 3-5: 40-50.

6. The method for preparing the anti-caking jujube powder according to claim 5, characterized in that: The preparation method of the tea water is as follows: 10 g of tea leaves are put into 500 g of water at 80-90° C. and soaked for 40-60 minutes.

7. The method for preparing the anti-caking jujube powder according to claim 1, characterized in that: In step 5, the composite auxiliary agent is a mixture of stevioside, whey protein, and Lactobacillus paracasei in a mass ratio of 0.5-1.5:10-18:4-5.

8. The method for preparing the anti-caking jujube powder according to claim 7, characterized in that: The preparation method of the composite auxiliary agent comprises the following steps: dissolving whey protein in water to prepare a whey protein solution with a mass fraction of 10-20%, adjusting the pH value of the whey protein solution to 6.5-7.5, adding stevioside, stirring to dissolve the stevioside in the solution, adding Lactobacillus paracasei, stirring, mixing evenly to prepare a mixed solution, subjecting the mixed solution to high-pressure homogenization, and spray drying to obtain the composite auxiliary agent.

9. The method for preparing the anti-caking jujube powder according to claim 7, characterized in that: In step five, the method for adding the composite auxiliary agent is as follows: at 0-2°C, first add the composite auxiliary agent to 5-8 times its volume of water and stir to mix evenly into a slurry; at the same time, add 3-4 times its volume of water to the red date powder and stir to mix evenly into a slurry; then mix the composite auxiliary agent slurry and the red date powder slurry evenly, concentrate under reduced pressure to 40-50% of the original solid weight, and then freeze and dry.

10. Anti-caking jujube powder, characterized in that: Prepared by any preparation method in claims 1 to 9.

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