Preparation technology of tea drinking debitterized grapefruit particle can

Abstract

The invention relates to the technical field of processing of debitterized grapefruit particle cans for tea drinking, and discloses a preparation process of the debitterized grapefruit particle cans for tea drinking, and the preparation process comprises the following steps: blanching grapefruit fruits, peeling and sectioning, and then carrying out enzymolysis treatment to obtain peel-removed grapefruit peel sections; blanching the peel-removed grapefruit peel segments with hot water, dissolving limonin in the peel-removed grapefruit peel segments, and synchronously removing the limonin dissolved in the peel-removed grapefruit peel segments by using a magnetic surface molecularly imprinted polymer to obtain debittered peel-removed grapefruit peel segments; and arranging and canning the debitterized and capsule-coat-removed grapefruit capsule segments, boiling with boiling water for sterilization, injecting a sugar solution, exhausting, sealing the can, sterilizing with boiling water, and cooling to room temperature to obtain the tea drinking debitterized grapefruit particle can. The magnetic surface molecularly imprinted polymer researched and developed by the invention can be used for removing limonin in a grapefruit particle can, and experimental results show that the magnetic surface molecularly imprinted polymer has good debitterizing performance.

Description

Technical Field

[0001] The present invention relates to the technical field of canned processing of tea-drinking bitter-free grapefruit granules, and specifically to a preparation process for canned tea-drinking bitter-free grapefruit granules. Background Art

[0002] The development of canned red grapefruit for tea drinking helps to realize the subcontracting processing of canned grapefruit granules, is conducive to improving the flavor and quality of grapefruit granules, and brings positive feedback to the final presentation of the product. However, the elimination of bitter substances is an important problem in the development technology of canned tea-drinking bitter-free grapefruit granules. Among them, limonin is one of the bitter components in grapefruit. Limonin mainly exists in the pulp of grapefruit, especially in the part close to the peel. When grapefruit is eaten, limonin will react with the enzymes in saliva to produce bitterness.

[0003] Therefore, the technology for removing limonin is a key technical problem that needs to be solved in the development process of canned tea-drinking bitter-free grapefruit granule products. Summary of the Invention

[0004] The present invention provides a preparation process for canned tea-drinking bitter-free grapefruit granules, which uses a newly developed magnetic surface molecularly imprinted polymer to achieve the technical purpose of removing limonin from canned grapefruit granules.

[0005] A preparation process for canned tea-drinking bitter-free grapefruit granules includes the following steps:

[0006] Step 1: Perform blanching treatment on the cleaned grapefruit fruits.

[0007] Step 2: Peel and segment the blanched grapefruit fruits to obtain grapefruit segments.

[0008] Step 3: Add the grapefruit segments to a pectinase solution for enzymatic hydrolysis treatment. After the enzymatic hydrolysis ends, rinse with running water to obtain de-membraned grapefruit segments.

[0009] Step 4: Perform hot water blanching on the de-membraned grapefruit segments to dissolve the limonin in the de-membraned grapefruit segments, and simultaneously use the magnetic surface molecularly imprinted polymer to remove the dissolved limonin in the de-membraned grapefruit segments to obtain bitter-free and de-membraned grapefruit segments.

[0010] Step 5: Arrange the bitter-free and de-membraned grapefruit segments and pack them into glass jars. Sterilize the glass jars by boiling in water, inject sugar solution while it is hot, exhaust air, seal the jars, sterilize by boiling in water, and cool to room temperature to obtain canned tea-drinking bitter-free grapefruit granules.

[0011] Preferably, the grapefruit fruits are blanched at a temperature of 90-100°C for 50-60 s.

[0012] Preferably, the enzymatic hydrolysis treatment parameters are: concentration 0.2 - 1.0%, temperature 45 - 50 °C, and time 30 - 90 min.

[0013] Preferably, the de - membraned pomelo segments are blanched in hot water at a temperature of 40 - 55 °C, and the hot water blanching time is controlled ≤ 60 s.

[0014] Preferably, the preparation method of the magnetic surface - molecularly imprinted polymer is as follows: Using the surface - imprinting method, with a tetracarboxy vinyl monomer as the functional monomer and limonin as the template molecule, the template molecule and the functional monomer are first pre - polymerized through hydrogen - bond interaction, and then under the combined action of an initiator, a cross - linker, and a catalyst, a polymerization reaction is carried out on the surface of Fe 3 O 4 @SiO 2 particles to obtain polymer particles, and finally the template molecule is removed with an eluent to obtain the magnetic surface - molecularly imprinted polymer.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects:

[0016] The present invention has developed a magnetic surface - molecularly imprinted polymer, which can be used for removing limonin in canned pomelo particles;

[0017] And the magnetic surface - molecularly imprinted polymer is used for removing limonin in de - membraned pomelo segments. The experimental results show that the magnetic surface - molecularly imprinted polymer has good debittering performance. Detailed implementation manners

[0018] Example 1:

[0019] A preparation process of canned tea - drinking debittered pomelo particles includes the following steps:

[0020] Step S1 - 1, blanch the cleaned pomelo fruit at 100 °C for 60 s;

[0021] Step S1 - 2, peel and segment the blanched pomelo fruit to obtain pomelo segments;

[0022] Step S1 - 3, according to the solid - liquid ratio of 1:2 (m:V), add the pomelo segments into a 1.0% pectinase solution (prepared by adding pectinase into a disodium hydrogen phosphate - citric acid buffer solution with pH = 5.0), enzymatically hydrolyze at a constant temperature of 50 °C in a water - bath for 1 h. After the enzymatic hydrolysis ends, rinse with running water to obtain de - membraned pomelo segments;

[0023] Step S1-4: Blanch the de-pulped grapefruit segments at 50°C for 60 s to dissolve the limonin in the de-pulped grapefruit segments, and simultaneously use magnetic surface molecularly imprinted polymer to remove the dissolved limonin in the de-pulped grapefruit segments, reducing the introduction of limonin into the canned grapefruit granules, and obtaining de-bittered and de-pulped grapefruit segments;

[0024] Step S1-5: Arrange the de-bittered and de-pulped grapefruit segments and pack them into glass jars. Boil the glass jars in boiling water for 15 min for sterilization, inject sugar solution while it is hot, so that the sugar content in the opened can is 14-18%, then place it in water at 85°C for exhaust treatment for 5 min. When the central temperature reaches 78°C, perform can sealing treatment. Finally, sterilize with boiling water at 100°C for 10 min and cool to room temperature to obtain the canned product of de-bittered grapefruit granules for tea drinking.

[0025] Example 2:

[0026] Prepare magnetic surface molecularly imprinted polymer, and its research and development process is as follows:

[0027] Process 1: Synthesize tetracarboxy vinyl monomer, and its specific synthesis method is as follows:

[0028] Step S2-1: Generate intermediate a through the primary amine reaction of phthalic anhydride and diethylenetriamine to protect the primary amine functional group of diethylenetriamine;

[0029] The experimental steps for synthesizing intermediate a are as follows: Add 14.8 g of phthalic anhydride to a three-necked flask, add 80 mL of glacial acetic acid to the three-necked flask, then add 5.3 mL of diethylenetriamine dropwise to the three-necked flask, reflux in an oil bath for 6 h, let it stand until the product precipitates, and wash with absolute ethanol to obtain intermediate a;

[0030] The chemical structural formula of intermediate a is:

[0031]

[0032] Step S2-2: The secondary amine functional group of intermediate a undergoes a substitution reaction with the bromine functional group of 3-bromopropene to generate intermediate b;

[0033] The experimental steps for synthesizing intermediate b are as follows: Add 16 g of intermediate a to a flask, add 3 mL of 3-bromopropene and 5 mL of triethylamine to the flask, then add 120 mL of N,N-dimethylformamide to the flask, heat and reflux for 18 h, cool, rotate and evaporate to remove N,N-dimethylformamide, and purify through a silica gel chromatography column (petroleum ether / ethyl acetate = 2 / 1, V / V) to obtain intermediate b;

[0034] The chemical structural formula of intermediate b is:

[0035]

[0036] Step S2-3: Remove the protecting group of intermediate b with hydrazine hydrate to obtain intermediate c;

[0037] The experimental procedure for synthesizing intermediate c is as follows: Add 4 g of intermediate b to a flask, add 50 mL of absolute ethanol and 6.5 mL of 80% hydrazine hydrate to the flask, reflux and react in an oil bath for 5 h, wash with water and ethyl acetate, filter, and vacuum dry at 40 °C for 12 h to obtain intermediate c;

[0038] The chemical structural formula of intermediate c is:

[0039]

[0040] Step S2-4: React sodium chloroacetate with the primary amine of intermediate c and perform acidification treatment to generate a tetracarboxy vinyl monomer;

[0041] The experimental procedure for synthesizing the tetracarboxy vinyl monomer is as follows: Add 1.29 g of intermediate c to a flask, add 80 mL of absolute ethanol and 20 mL of deionized water to the flask, then add 3.6 g of sodium hydroxide to the flask, and then add 10.5 g of sodium chloroacetate to the three-necked flask, reflux and react for 24 h. After the reaction is completed, titrate with 1 mol / L hydrochloric acid until no precipitate is formed, perform centrifugal separation, and vacuum dry at 50 °C for 12 h to obtain the tetracarboxy vinyl monomer;

[0042] The chemical structural formula of the tetracarboxy vinyl monomer is:

[0043]

[0044] The hydrogen spectrum characterization result of the tetracarboxy vinyl monomer is: 1 H NMR(400MHz, CDCl 3 , δ, ppm): 2.48 - 2.58(m, 8H), 3.04 - 3.06(d, 2H), 3.88(s, 8H), 5.18 - 5.22(d, 2H), 5.78 - 5.88(m, 1H).

[0045] Process Two: Prepare Fe 3 O 4 @SiO 2 particles, and the specific method is as follows:

[0046] Prepare Fe 3 O 4Magnetic particles: Dissolve 7.2 g of ferric chloride hexahydrate in 150 mL of ethylene glycol, add 14.4 g of anhydrous sodium acetate and 4 g of polyethylene glycol 2000, stir for 1 h at 50 °C in a water bath, then transfer to a reaction kettle, place the reaction kettle in an electrothermal constant temperature oven, set the temperature to 200 °C and react for 8 h. After the reaction is completed, transfer to a centrifuge tube, perform magnetic separation, wash with ethanol and distilled water, and vacuum dry at 60 °C for 12 h, and freeze-dry for standby;

[0047] Preparation of Fe 3 O 4 @SiO 2 particles: Dissolve 1.2 g of Fe 3 O 4 magnetic particles in a mixed solution containing 160 mL of absolute ethanol, 40 mL of deionized water and 2 mL of concentrated ammonia water, pour into a three-necked flask, and use a constant pressure dropping funnel to drop 800 μL of tetraethyl orthosilicate at a rate of 1 drop / 8 s, perform magnetic separation, wash with ethanol and distilled water, and freeze-dry for standby;

[0048] Preparation of Fe 3 O 4 @SiO 2 particles with double bonds on the surface: Dissolve 1.2 g of Fe 3 O 4 @SiO 2 particles in a mixed solution containing 150 mL of absolute ethanol and 50 mL of deionized water, adjust the pH value to 9.32 with ammonia water, use a constant pressure dropping funnel to drop 50 mL of an absolute ethanol solution containing 0.36 g of KH-570 silane coupling agent at a rate of 1 drop / 8 s, adjust the pH value of the solution to 9.32 with a pH meter, and then react at room temperature for 24 h, perform magnetic separation, wash with ethanol and distilled water, and obtain Fe 3 O 4 @SiO 2 particles with double bonds on the surface;

[0049] Process three: Preparation of magnetic surface molecularly imprinted polymer, and its specific process is as follows:

[0050] Dissolve 1.5 g of tetracarboxy vinyl monomer and 0.47 g of limonin in 120 mL of acetonitrile, ultrasonically disperse for 0.5 h, and pre-polymerize for 6 h;

[0051] Add 0.5 g of Fe 3 O 4 @SiO 2Particles, 5.9 g of ethylene glycol dimethacrylate, 0.2 g of azobisisobutyronitrile, and 0.1 g of anhydrous potassium carbonate were charged with nitrogen for 10 min, sealed, and reacted in a water bath shaker at 65 °C for 24 h. The polymer was collected by magnetic separation, washed successively with anhydrous ethanol and deionized water, and vacuum dried at 50 °C for 12 h;

[0052] The polymer was eluted with a mixed solution (V(methanol):V(glacial acetic acid)=9:1) until no limonin molecules were detected in the washing solution, washed with deionized water, and finally vacuum dried at 60 °C for 24 h to obtain magnetic surface molecularly imprinted polymer;

[0053] Process Four: The magnetic surface molecularly imprinted polymer was used to remove limonin. The specific experimental process was as follows:

[0054] Prepare a limonin standard solution:

[0055] Accurately weigh 10 mg of limonin standard sample, completely dissolve it with anhydrous ethanol and make up the volume to 50 mL to prepare a limonin standard solution with a concentration of 200 μg / mL;

[0056] Accurately weigh 50 mg of limonin standard sample, completely dissolve it with anhydrous ethanol and make up the volume to 50 mL to prepare a limonin standard solution with a concentration of 1000 μg / mL;

[0057] Accurately weigh 100 mg of limonin standard sample, completely dissolve it with anhydrous ethanol and make up the volume to 50 mL to prepare a limonin standard solution with a concentration of 2000 μg / mL;

[0058] Accurately weigh 1000 mg of limonin standard sample, completely dissolve it with anhydrous ethanol and make up the volume to 50 mL to prepare a limonin standard solution with a concentration of 20000 μg / mL;

[0059] Add 50 mg of magnetic surface molecularly imprinted polymer to a 50 mL Erlenmeyer flask containing 10 mL of limonin standard solution (the concentration of experiment No. 1 is 200 μg / mL, the concentration of experiment No. 2 is 1000 μg / mL, and the concentration of experiment No. 3 is 2000 μg / mL). Place the Erlenmeyer flask in a constant temperature shaker and shake at a constant speed of 25 °C and 180 rpm for 1 h. The magnetic surface molecularly imprinted polymer was collected by magnetic separation, and the limonin adsorbed by the magnetic surface molecularly imprinted polymer was ultrasonically eluted with 2 mL of methanol. The eluate was evaporated to dryness, redissolved with 3 mL of methanol, and the content of limonin was detected by HPLC;

[0060] Among them, the HPLC analysis conditions were:

[0061] Using an Agilent 1260 system, the chromatographic column is TC-C 18 column (250 mm × 4.6 mm, 5 μm);

[0062] Flow rate: 0.6 mL / min;

[0063] Column temperature: 30 °C;

[0064] Using a mobile phase consisting of 55% acetonitrile and 45% 0.1% phosphoric acid aqueous solution;

[0065] Injection volume: 10 μL;

[0066] Detection wavelength: 210 nm;

[0067] Calculate the removal amount and removal rate of limonin by the magnetic surface molecularly imprinted polymer. The experimental results are shown in Table 1 below;

[0068] Table 1 Removal experimental results of the magnetic surface molecularly imprinted polymer

[0069] Experiment number Dosage of limonin (μg) Removed amount of limonin (μg) Removal rate (%) 1 2000 1998 99.90 2 10000 9994 99.94 3 20000 19959 99.80

[0070] From the removal experimental results of the magnetic surface molecularly imprinted polymer, it can be seen that the magnetic surface molecularly imprinted polymer can be used to remove limonin, that is, the magnetic surface molecularly imprinted polymer can be used to remove the limonin dissolved in the dehulled grapefruit segments, reducing the introduction of limonin in canned grapefruit granules.

Claims

1. A process for preparing canned debittered grapefruit granules for tea drinking, characterized in that: The following steps are involved: Step 1: blanching the cleaned grapefruit; Step 2, peeling and segmenting the grapefruit fruit after the blanching treatment to obtain grapefruit segments; Step 3, adding the grapefruit pods into a pectinase solution for enzymatic hydrolysis, and after the enzymatic hydrolysis is completed, rinsing with running water to obtain the de-shelled grapefruit pods; Step 4, blanching the peeled grapefruit segments with hot water to dissolve the limonin in the peeled grapefruit segments, and simultaneously removing the limonin dissolved in the peeled grapefruit segments using a magnetic surface molecular imprinting polymer to obtain debittered peeled grapefruit segments; Step 5, sort out the debittered and decapsulated grapefruit capsules and put them into glass jars, sterilize the glass jars with boiling water, inject sugar solution while it is still hot, vent, seal the jars, sterilize with boiling water, and cool to room temperature to obtain canned debittered grapefruit granules for tea drinking.

2. The preparation process of the canned debittered grapefruit granules for tea drinking according to claim 1, characterized in that: The grapefruit is blanched at a temperature of 90-100°C for 50-60 seconds.

3. The preparation process of the canned debittered grapefruit granules for tea drinking according to claim 1, characterized in that: The parameters of the enzymatic treatment are: concentration 0.2-1.0%, temperature 45-50°C, and time 30-90min.

4. The process for preparing the canned debittered grapefruit granules for tea drinking according to claim 1, characterized in that: The decapsulated grapefruit segments are blanched in hot water at a temperature of 40-55°C, and the blanching time is controlled to be ≤60s.

5. The preparation process of the canned debittered grapefruit granules for tea drinking according to claim 1, characterized in that: The preparation method of magnetic surface molecular imprinted polymer is as follows: using the surface imprinting method, tetracarboxylic alkenyl monomer is used as functional monomer, limonin is used as template molecule, the template molecule and the functional monomer are firstly prepolymerized through hydrogen bonding, and then polymerization reaction is carried out on the surface of Fe3O4@SiO2 particles modified with double bonds under the joint action of initiator, crosslinking agent and catalyst to obtain polymer particles, and finally the template molecule is removed by eluent to obtain magnetic surface molecular imprinted polymer.

6. The process for preparing the canned debittered grapefruit granules for tea drinking according to claim 5, characterized in that: The chemical formula of the tetracarboxylic olefinic monomer is:

7. The process for preparing the canned debittered grapefruit granules for tea drinking according to claim 5, characterized in that: The synthesis method of tetracarboxyl olefin monomer is: The intermediate a is generated by the reaction of phthalic anhydride and the primary amine of diethylenetriamine, and its chemical structure is: The secondary amine functional group of intermediate a undergoes a substitution reaction with the bromine functional group of 3-bromopropylene to generate intermediate b, whose chemical structure is: The protecting group of intermediate b is removed by hydrazine hydrate to obtain intermediate c, whose chemical structure is: The tetracarboxylic olefin monomer is generated by reacting sodium chloroacetate with the primary amine of intermediate c and acidifying the monomer.

8. The process for preparing the canned debittered grapefruit granules for tea drinking according to claim 5, characterized in that: The initiator is azobisisobutyronitrile; The crosslinking agent is ethylene glycol dimethacrylate; The catalyst is anhydrous potassium carbonate.

9. The process for preparing the canned debittered grapefruit granules for tea drinking according to claim 5, characterized in that: The eluent consisted of 9 parts by volume of methanol and 1 part by volume of glacial acetic acid.

10. A can of debittered grapefruit granules for tea drinking prepared by the process according to any one of claims 1 to 9, characterized in that: Limonin in canned debittered grapefruit granules for tea drinking was removed by magnetic surface molecular imprinting polymer.

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