Debitterizing method and debitterizing preparation of frozen pomelo cysts

Abstract

The invention discloses a debitterizing method and debitterizing preparation for frozen pomelo cysts, and relates to the technical field of food processing.The debitterizing method comprises the steps that the pomelo cysts are placed in an ethylene diamine tetraacetic acid disodium solution with the mass concentration being 0.5-2.5% to be soaked for 15-75 min, and then freezing is conducted. By utilizing the method, the ethylene diamine tetraacetic acid can inhibit the activity of limonin D-ring lactone hydrolase, so that the generation of limonin is reduced from the source, and a relatively good debitterizing effect is achieved. On the basis, a composite debitterizing method with a better effect is further explored, that is, after soaking treatment is conducted through an ethylene diamine tetraacetic acid solution, treatment is conducted through a beta-cyclodextrin solution or treatment is conducted through a high-voltage electric field and the beta-cyclodextrin solution in sequence, and the removal rate of limonin is remarkably increased. The debitterizing method, especially the composite debitterizing method, provided by the invention is good in debitterizing effect, can be widely applied to freezing storage of pomelo cysts, and is high in production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a debittering method for frozen pomelo cysts and a debittering preparation. Background Art

[0002] Pomelo is a species of plant in the genus Citrus of the Rutaceae family. It has been cultivated in my country for more than 3,000 years and is widely popular for its unique flavor and taste. Pomelo is rich in various bioactive compounds, including flavonoids, limonoids, vitamin C, β-carotene and dietary fiber, and has health benefits such as antioxidant, anti-inflammatory and anti-tumor. Pomelo cysts are individual fruit grains obtained by dispersing the pomelo after peeling and removing the cysts. Pomelo cysts are usually processed into canned food, which can not only be eaten directly, but also used as an ingredient for beverages. Some factories adopt the method of freezing pomelo fruits to supply production throughout the year, but freezing makes the pomelo pulp bitter. The bitterness of the pulp is mainly caused by flavonoids and limonoids, and the representative compounds are naringin and limonin. After citrus fruits are physically damaged by freezing and juicing, the conversion of limonin A-ring lactone to limonin occurs under the action of limonin D-ring lactone hydrolase, thereby converting the non-bitter limonin precursor into a bitter substance.

[0003] In the past, citrus debittering mainly focused on citrus juice, and there were few methods for debittering citrus cysts. Common debittering methods for citrus juice include adsorption, β-cyclodextrin embedding, naringinase hydrolysis, microbial fermentation, etc. However, these methods all have some shortcomings. Specifically, the adsorption method and β-cyclodextrin embedding method have poor selectivity, which reduces the nutrition and flavor of the juice while removing bitter substances, and the embedding rate of β-cyclodextrin for bitter substances is not high. The Chinese invention patent with announcement number CN118592542A discloses grapefruit juice with improved clarity and debittering effect and its preparation method, using naringinase for debittering, naringinase can only specifically degrade naringin and has no effect on limonin, and microbial fermentation actually uses its metabolic enzymes to play a role, and limonin degrading enzymes are usually active under alkaline conditions, so this method also needs to regulate the system to be alkaline. Moreover, the above methods all remove limonin after it is produced, and it is difficult to achieve a good removal effect.

[0004] The Chinese invention patent with publication number CN113925146A discloses a debittering ultrafine grapefruit powder and its production method and use, which uses a composite process for debittering, and uses ultrasonic enzyme inactivation combined with sodium chloride, sodium carbonate, and sodium bicarbonate to passivate and remove limonin D-ring lactone hydrolase in the pulp and remove limonin. It can be seen that inhibiting the activity of limonin D-ring lactone hydrolase and reducing the production of limonin through a composite process can also be used as a new idea for debittering citrus. Summary of the Invention

[0005] The object of the present invention is to provide an efficient method for debittering frozen pomelo vesicles, in particular a method that can significantly inhibit the activity of limonin D-ring lactone hydrolase in pomelo vesicles, reduce the generation of limonin, so as to achieve debittering of pomelo vesicles, and preferably maintain the original texture and flavor of pomelo vesicles.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention provides a method for debittering frozen pomelo vesicles, which is to soak the pomelo vesicles in a disodium ethylenediaminetetraacetate solution with a mass concentration of 0.5 - 2.5% for 15 - 75 min and then freeze them.

[0008] Preferably, the concentration of the disodium ethylenediaminetetraacetate solution is 1 - 2%.

[0009] More preferably, the concentration of the disodium ethylenediaminetetraacetate solution is 1.5%.

[0010] Preferably, the soaking time of the disodium ethylenediaminetetraacetate solution is 30 - 60 min.

[0011] More preferably, the soaking time of the disodium ethylenediaminetetraacetate solution is 30 min.

[0012] By soaking the pomelo vesicles in the disodium ethylenediaminetetraacetate solution, after soaking, the activity of limonin D-ring lactone hydrolase is significantly inhibited, and the conversion of limonin precursors in the pomelo vesicles into limonin during the physical destruction process of freezing and thawing is reduced. In addition, β-cyclodextrin solution is further used in combination to bind the limonin present in the vesicles after thawing into its cavity. Finally, the bitterness of the pomelo vesicles is reduced, and the original texture and flavor of the pomelo vesicles are preferably maintained.

[0013] Therefore, further preferably, the method for debittering frozen pomelo vesicles includes the following steps:

[0014] S1. Soak the pomelo vesicles in a disodium ethylenediaminetetraacetate solution with a mass concentration of 0.5 - 2.5% for 15 - 75 min;

[0015] S2. Freeze and thaw the pomelo vesicles treated in S1;

[0016] S3. Soak the thawed pomelo vesicles in β-cyclodextrin solution to obtain debittered pomelo vesicles.

[0017] Preferably, the mass concentration of the β-cyclodextrin solution is 0.5 - 2.5%.

[0018] Preferably, the soaking time of the β-cyclodextrin solution is not less than 30 min.

[0019] The present invention further discovers through research that after the citrus segments are soaked in a disodium ethylenediaminetetraacetate solution and then treated with a high-voltage electric field, the activity of limonin D-ring lactone hydrolase can be synergistically inhibited, and β-cyclodextrin solution is used in combination to bind the limonin present in the thawed segments into its cavity, more significantly reducing the bitterness of the citrus segments while maintaining the original texture and flavor of the citrus segments.

[0020] Therefore, more preferably, the method for debittering frozen citrus segments includes the following steps:

[0021] S1. Soak the citrus segments in a disodium ethylenediaminetetraacetate solution with a mass concentration of 0.5 - 2.5% for 15 - 75 min;

[0022] S2. Place the citrus segments treated in S1 under a high-voltage electric field of 2.5 - 30 KV for 0.5 - 6 h, then freeze and thaw them;

[0023] S3. Soak the thawed citrus segments with β-cyclodextrin solution to obtain debittered citrus segments.

[0024] In the above debittering method, preferably, the concentration of the disodium ethylenediaminetetraacetate solution is 1 - 2%, and more preferably 1.5%.

[0025] Preferably, the soaking time in the disodium ethylenediaminetetraacetate solution is preferably 30 - 60 min, and more preferably 30 min.

[0026] Preferably, the voltage of the high-voltage electric field is preferably 10 - 30 KV, and more preferably 10 KV.

[0027] Preferably, the treatment time under the high-voltage electric field is preferably 4 - 6 h, and more preferably 4 h.

[0028] Preferably, the mass concentration of the β-cyclodextrin solution is 0.5 - 2.5%.

[0029] Preferably, the soaking time in the β-cyclodextrin solution is not less than 30 min.

[0030] Preferably, the soaking treatment is carried out at 25 - 30 °C. After the soaking treatment, the soaking solution on the surface of the citrus segments needs to be removed.

[0031] Further, the water on the surface of the citrus segments needs to be removed before the citrus segments are placed under the high-voltage electric field for treatment.

[0032] Further, the freezing is low-temperature freezing at -20 to -100 °C. Preferably, it is low-temperature freezing at -40 to -80 °C, and more preferably -80 °C.

[0033] In addition, further, the citrus segments are taken from the fruits of plants in the genus Citrus of the Rutaceae family.

[0034] Preferably, the fruits of the plants of the genus Citrus in the Rutaceae family can be honey pomelos, oranges, tangors, citrons, sweet oranges, grapefruits, pomelos, limes, etc.

[0035] Furthermore, the method for obtaining the grapefruit vesicles is to peel the fruits of the plants of the genus Citrus in the Rutaceae family, remove the albedo, and disperse the obtained pulp to obtain individual grapefruit vesicles.

[0036] The present invention also provides the use of disodium ethylenediaminetetraacetate in the preparation of an inhibitor of limonin D-ring lactone hydrolase or as an inhibitor of limonin D-ring lactone hydrolase.

[0037] The present invention also provides the use of disodium ethylenediaminetetraacetate in removing limonin or debittering frozen grapefruit vesicles, or in the preparation of a debittering preparation for limonin.

[0038] The present invention provides a composition for inhibiting the activity of limonin D-ring lactone hydrolase and / or removing limonin and / or debittering frozen grapefruit vesicles, the composition comprising disodium ethylenediaminetetraacetate and cyclodextrin used separately; preferably, the disodium ethylenediaminetetraacetate is present in the form of a solution with a mass concentration of 0.5-2.5%.

[0039] Furthermore, the mass concentration of the cyclodextrin solution is 0.5-2.5%.

[0040] Preferably, the cyclodextrin is β-cyclodextrin.

[0041] Furthermore, the composition is prepared by first mixing the raw material to be inhibited for the activity of limonin D-ring lactone hydrolase and / or the raw material to be removed of limonin with the disodium ethylenediaminetetraacetate solution, freezing, and then mixing with the cyclodextrin solution.

[0042] The beneficial effects of the present invention are as follows:

[0043] (1) By soaking the grapefruit vesicles with the disodium ethylenediaminetetraacetate solution, the present invention can significantly inhibit the activity of limonin D-ring lactone hydrolase, reduce the conversion of limonin precursors in the grapefruit vesicles into limonin during the physical destruction process of freezing and thawing, and achieve the debittering effect.

[0044] (2) By using a composite debittering method to treat the grapefruit vesicles, soaking the grapefruit vesicles in the disodium ethylenediaminetetraacetate solution and jointly using the β-cyclodextrin solution to bind the limonin present in the thawed vesicles into its cavity; significantly inhibiting the activity of limonin D-ring lactone hydrolase, reducing the production of limonin, improving the removal rate of limonin, and better maintaining the texture and flavor while reducing the bitterness of the vesicles.

[0045] (3) The composite debittering method of the frozen pomelo vesicles in the present invention further combines the soaking in disodium ethylenediaminetetraacetate solution and the treatment of the pomelo vesicles with high-voltage electric field, synergistically inhibits the activity of limonin D-ring lactone hydrolase, and combines the use of β-cyclodextrin solution to bind the limonin existing in the thawed vesicles into its cavity, more significantly reducing the bitterness of the pomelo vesicles and maintaining the original texture and flavor of the pomelo vesicles.

[0046] (4) The composite debittering method of the frozen pomelo vesicles in the present invention has good debittering effect and can be widely applied to the frozen storage of pomelo vesicles to improve production efficiency.

[0047] (5) The present invention provides various applications of disodium ethylenediaminetetraacetate and cyclodextrin in the debittering of frozen pomelo vesicles. It includes the application of disodium ethylenediaminetetraacetate as or in the preparation of an inhibitor of limonin D-ring lactone hydrolase, and provides a composition for inhibiting the activity of limonin D-ring lactone hydrolase and / or removing limonin and / or for debittering frozen pomelo vesicles, and the composition includes disodium ethylenediaminetetraacetate and cyclodextrin at specific concentrations. Description of the Drawings

[0048] Figure 1 Shows the influence of the concentration of sodium ethylenediaminetetraacetate in Example 1 on the removal rate of limonin and the inhibition rate of enzyme activity.

[0049] Figure 2 Shows the influence of the treatment time of sodium ethylenediaminetetraacetate in Example 2 on the removal rate of limonin.

[0050] Figure 3 Shows the influence of the electric field strength in Example 3 on the removal rate of limonin and the inhibition rate of enzyme activity.

[0051] Figure 4 Shows the influence of the electric field time in Example 4 on the removal rate of limonin.

[0052] Figure 5 Shows the influence of the concentration of β-cyclodextrin in Example 5 on the removal rate of limonin.

[0053] Figure 6 Shows the influence of the composite debittering method in Examples 6 - 10 on the removal rate of limonin;

[0054] Figure 6 In which, EF represents the electric field treatment, β-CD represents the soaking treatment with β-cyclodextrin solution, and EDTA-2Na represents the soaking treatment with disodium ethylenediaminetetraacetate solution. Detailed Embodiments

[0055] The present invention uses pomelo as the raw material to illustrate the effect of the composite debittering method on its frozen vesicles. However, the present invention is not limited to pomelo and is also applicable to other pomelo varieties that produce limonin during the freezing and thawing process. The technical solution of the present invention will be further described below in combination with specific examples and comparative examples.

[0056] Example 1 Debittering of Frozen Pomelo Vesicles with Different Concentrations of Disodium Ethylenediaminetetraacetate Solution

[0057] This example provides a method for debittering frozen pomelo vesicles. The method is to soak the pomelo vesicles in a disodium ethylenediaminetetraacetate solution with a specific concentration and then freeze them to debitter the pomelo vesicles that need to be frozen for transportation or storage. The specific method is as follows:

[0058] Manually peel and remove the albedo of fresh pomelo, and manually disperse the pulp to obtain pomelo vesicles. Prepare disodium ethylenediaminetetraacetate solutions with mass concentrations of 0.5%, 1.0%, 1.5%, 2.0%, and 2.5% respectively. Soak the pomelo vesicles at 30 °C for 30 min, and the solid-liquid ratio is 1:3. Remove the disodium ethylenediaminetetraacetate solution, wash the residual solution on the surface of the pomelo vesicles with clean water, and then freeze the pomelo vesicles at -80 °C.

[0059] Example 2 Debittering of Frozen Pomelo Vesicles with Different Treatment Times of Disodium Ethylenediaminetetraacetate Solution

[0060] This example provides a method for debittering frozen pomelo vesicles. The method is to soak the pomelo vesicles in a disodium ethylenediaminetetraacetate solution for a certain time and then freeze them to debitter the pomelo vesicles that need to be frozen for transportation or storage. The specific method is as follows:

[0061] Manually peel and remove the albedo of fresh pomelo, and manually disperse the pulp to obtain pomelo vesicles. Prepare a disodium ethylenediaminetetraacetate solution with a mass concentration of 1.5%. Soak the pomelo vesicles at 30 °C for 15 min, 30 min, 45 min, 60 min, and 75 min respectively, and the solid-liquid ratio is 1:3. Remove the disodium ethylenediaminetetraacetate solution, wash the residual solution on the surface of the pomelo vesicles with clean water, and then freeze the pomelo vesicles at -80 °C.

[0062] Example 3 Debittering of Frozen Pomelo Vesicles with Different Electric Field Strengths

[0063] This example provides a method for debittering frozen pomelo vesicles. The method is to treat the pomelo vesicles under a specific high-voltage electric field and then freeze them to obtain debittered pomelo vesicles. The specific method is as follows:

[0064] Manually peel and remove the albedo of fresh pomelo, and manually disperse the pulp to obtain pomelo vesicles. Treat them at room temperature under electric fields of 2.5 kV, 5 kV, 10 kV, 20 kV, and 30 kV for 4 h respectively, and then freeze the pomelo vesicles at -80 °C.

[0065] Example 4 Effect of Different Electric Field Treatment Times on Debittering of Frozen Pomelo Sacs

[0066] This example provides a method for debittering frozen pomelo sacs. The method is to place the pomelo sacs under a high - voltage electric field for a certain period of time and then freeze them to obtain debittered pomelo sacs. The specific method is as follows:

[0067] Manually peel and remove the albedo of fresh pomelos, and manually disperse the pulp to obtain pomelo sacs. At room temperature, treat them under an electric field of 10 kV for 0.5 h, 1 h, 2 h, 4 h, and 6 h respectively, and then freeze the pomelo sacs at - 80 °C.

[0068] Example 5 Effect of Different Concentrations of β - Cyclodextrin Solution on Debittering of Frozen Pomelo Sacs

[0069] This example provides a method for debittering frozen pomelo sacs. The method is to place the frozen - thawed pomelo sacs under different concentrations of β - cyclodextrin solution for treatment to obtain debittered pomelo sacs. The specific method is as follows:

[0070] Manually peel and remove the albedo of fresh pomelos, and manually disperse the pulp to obtain pomelo sacs. Freeze the pomelo sacs at - 80 °C for 48 h, and thaw them statically at room temperature for 6 h. Prepare β - cyclodextrin solutions with concentrations of 0.5%, 1.0%, 1.5%, 2.0%, and 2.5% respectively, and soak the thawed pomelo sacs at room temperature for 30 min, with a solid - liquid ratio of 1:3. After removing the β - cyclodextrin solution and washing the residual solution on the surface of the pomelo sacs with clean water, debittered pomelo sacs are obtained.

[0071] Example 6 Composite Debittering Method for Debittering of Frozen Pomelo Sacs

[0072] This example provides a composite debittering method for frozen pomelo sacs. The method is to soak the pomelo sacs in disodium ethylenediaminetetraacetate solution, treat them under a high - voltage electric field, and then soak them in β - cyclodextrin solution after freezing and thawing. It specifically includes the following steps:

[0073] S1. Peel the pomelo fruit and remove the albedo, and disperse the obtained pulp to obtain single pomelo sacs; place the pomelo sacs of the fruit of the genus Citrus in Rutaceae in a soaking solution of disodium ethylenediaminetetraacetate with a mass concentration of 1.5% for soaking treatment, and the soaking time is 30 min; the soaking treatment is carried out at 25 °C, and after the soaking treatment, remove the soaking solution on the surface of the pomelo sacs.

[0074] S2. Remove the moisture on the surface of the pomelo sacs treated in S1 and place them under a high - voltage electric field for treatment; the high - voltage electric field (EF) is 10 kV, and the treatment time under the high - voltage electric field is 4 h.

[0075] S3. Freeze the processed pomelo vesicles at -80°C for 48 h, thaw them statically at room temperature for 6 h, and soak the thawed pomelo vesicles in a β-cyclodextrin solution as the soaking liquid. The solid-liquid ratio is 1:3, and the soaking time is at least 30 min to obtain de-bittered pomelo vesicles. The mass concentration of the β-cyclodextrin solution is 2.5%.

[0076] Example 6 is denoted as EDTA-2Na + EF + β-CD.

[0077] Example 7 Debittering of Frozen Pomelo Vesicles by Composite Debittering Method

[0078] This example provides a method for debittering frozen pomelo vesicles. First, the pomelo vesicles are treated with an electric field, then frozen and thawed, and then soaked in a β-cyclodextrin solution. The specific steps are as follows:

[0079] Manually peel and remove the sac coat from fresh pomelo, and manually disperse the pulp to obtain pomelo vesicles. The vesicles are treated in a 10 kV electric field (EF) for 4 h, then frozen at -80°C for 48 h, thawed statically at room temperature for 6 h, and then soaked in a 2.5% β-cyclodextrin solution (β-CD) at a solid-liquid ratio of 1:3 at room temperature for 30 min.

[0080] Example 7 is denoted as EF + β-CD.

[0081] Example 8 Debittering of Frozen Pomelo Vesicles by Composite Debittering Method

[0082] This example provides a method for debittering frozen pomelo vesicles. First, the pomelo vesicles are treated with a disodium ethylenediaminetetraacetate solution, then frozen and thawed, and then soaked in a β-cyclodextrin solution. The specific steps are as follows:

[0083] Manually peel and remove the sac coat from fresh pomelo, and manually disperse the pulp to obtain pomelo vesicles. The vesicles are soaked in a 1.5% disodium ethylenediaminetetraacetate solution (EDTA-2Na) for 30 min, then frozen at -80°C for 48 h, thawed statically at room temperature for 6 h, and after thawing, soaked in a 2.5% β-cyclodextrin solution at a solid-liquid ratio of 1:3 at room temperature for 30 min.

[0084] Example 8 is denoted as EDTA-2Na + β-CD.

[0085] Example 9 Debittering of Frozen Pomelo Vesicles by Composite Debittering Method

[0086] This example provides a method for debittering frozen pomelo vesicles. First, the pomelo vesicles are treated with a disodium ethylenediaminetetraacetate solution, then subjected to an electric field treatment and then frozen. The specific steps are as follows:

[0087] The fresh pomelos are manually peeled and the albedo is removed, and the pulp is manually dispersed to obtain pomelo vesicles. The vesicles are soaked in a 1.5% disodium ethylenediaminetetraacetate solution for 30 min, and then treated in a 10 kV electric field for 4 h. The treated vesicles are frozen at -80 °C.

[0088] Example 9 is denoted as EDTA-2Na + EF.

[0089] Example 10 The composite debittering method is used to debitter the frozen pomelo vesicles

[0090] This example provides a method for debittering frozen pomelo vesicles. The pomelo vesicles are first treated with an electric field, then soaked in a disodium ethylenediaminetetraacetate solution, and then frozen. The specific steps are as follows:

[0091] The fresh pomelos are manually peeled and the albedo is removed, and the pulp is manually dispersed to obtain pomelo vesicles. The vesicles are treated in a 10 kV electric field for 4 h, and then soaked in a 1.5% disodium ethylenediaminetetraacetate solution for 30 min. The treated vesicles are frozen at -80 °C.

[0092] Example 10 is denoted as EF + EDTA-2Na.

[0093] Comparative Example 1

[0094] The fresh pomelos are manually peeled and the albedo is removed, and the pulp is manually dispersed to obtain pomelo vesicles. The vesicles are frozen at -80 °C for 48 h without any debittering treatment and thawed statically at room temperature for 6 h. This is used as the benchmark for calculating the removal rate of limonin in the frozen pomelo vesicles.

[0095] Example 11

[0096] 1. Experimental method

[0097] The content of bitter substances (limonin) in pomelo vesicles is determined by high performance liquid chromatography; the Ultimate 3000 high performance liquid chromatography system of Thermo Fisher Scientific, USA is used to quantify the limonin in pomelo vesicles, and the activity of limonin D-ring lactone hydrolase is determined. The specific method is as follows:

[0098] (1) Determination of limonin content: The pomelo vesicles were thoroughly ground in a mortar, and dichloromethane was added at a ratio of 1:2 (w / v). Ultrasonic extraction was carried out at 300 W for 1.5 h at room temperature. The extract was centrifuged at 8000 rpm for 15 min, and the lower clear liquid was taken. After evaporating the dichloromethane to dryness, it was reconstituted in 2 mL of acetonitrile, filtered through a 0.22 μm membrane, and injected into a 1.5 mL sample vial using a syringe. Test conditions: The chromatographic column model was ChromCore AQ C18 (5 μm, 4.6×250 mm), the injection volume was 10 μL, the flow rate was 1 mL / min, the detection wavelength was 210 nm, the column temperature was controlled at 30 °C, isocratic elution was used, and the mobile phase ratio was acetonitrile:water = 45:55. Determination of the activity of limonin D-ring lactone hydrolase

[0099] (2) Purification of limonin D-ring lactone hydrolase: The freeze-dried pomelo vesicles were ground into powder with liquid nitrogen and suspended in 3 volumes of an aqueous mixture (prepared by dissolving 1% NaCl, 1% PVPP, and 0.5% SDS in water). After incubating the suspension at 4 °C for 12 h, it was filtered through coarse cotton cloth and centrifuged until clear. The protein was precipitated with 80% ammonium sulfate, the supernatant was decanted after centrifugation, and the precipitate was dissolved in phosphate buffer (10 mM, pH = 7.2). The protein solution was dialyzed for 24 h and then used for activity analysis.

[0100] (3) Determination of the activity of limonin D-ring lactone hydrolase: After mixing the enzyme sample (1200 μL) with phosphate buffer (200 μL, 1 M, pH = 8.0), a limonin acetonitrile solution (200 μL, 5 mg / mL) was added for reaction. The unreacted limonin was washed and collected through a C18 column, quantified by HPLC, and the mass of limonin precursor (LARL) generated in the reaction was calculated. The amount of enzyme required to catalyze the production of 1 μmol of LARL in 1 min was defined as one enzyme activity unit (U), and the enzyme activity inhibition rate was calculated therefrom.

[0101] According to the above method, the limonin content in the thawed frozen pomelo vesicles in Examples 1-10 and Comparative Example 1 was measured respectively. The activity of limonin D-ring lactone hydrolase in Examples 1 and 3 was tested. The freezing time of the treated pomelo vesicles was controlled to be the same, 48 h, and the thawing condition was static thawing at room temperature for 6 h.

[0102] The removal rate of limonin from frozen pomelo vesicles was based on the limonin in the frozen pomelo vesicles of Comparative Example 1. After the debittering treatment of the frozen pomelo vesicles by the debittering methods in Examples 1-10, the percentage of the removal amount of limonin relative to the limonin in the frozen pomelo vesicles of Comparative Example 1 in the limonin in the frozen pomelo vesicles of Comparative Example 1 was the removal rate of limonin.

[0103] 2. Experimental results

[0104] (1) Effect of soaking in disodium ethylenediaminetetraacetate solution on the activity of limonin D-ring lactone hydrolase and limonin removal rate

[0105] It can be seen from Figure 1 that soaking in disodium ethylenediaminetetraacetate solution can inhibit the activity of limonin D-ring lactone hydrolase and remove limonin; and as the concentration of disodium ethylenediaminetetraacetate solution increases, the inhibition rate of limonin D-ring lactone hydrolase and the limonin removal rate increase first and then decrease, and the removal rate is the highest when the mass concentration is 1.5%.

[0106] It can be seen from Figure 2 that when the treatment time with 1.5% mass concentration of disodium ethylenediaminetetraacetate solution increases from 15 min to 30 min, the limonin removal rate increases significantly, and when the time continues to increase, the removal rate does not increase significantly.

[0107] Therefore, the best debittering effect is achieved by treating with 1.5% mass concentration of disodium ethylenediaminetetraacetate solution for 30 min.

[0108] (2) Effect of electric field treatment on the activity of limonin D-ring lactone hydrolase and limonin removal rate

[0109] It can be seen from Figure 3 that electric field treatment can inhibit the activity of limonin D-ring lactone hydrolase and remove limonin; and when the electric field strength increases from 2.5 kV to 10 kV, the inhibition rate of limonin D-ring lactone hydrolase and the limonin removal rate increase significantly, and there is no significant change when the electric field strength continues to increase. Therefore, 10 kV is selected as the best electric field strength.

[0110] It can be seen from Figure 4 that when the electric field treatment time increases from 0.5 h to 4 h, the limonin removal rate increases significantly, and when the treatment time is extended to 6 h, the removal rate does not increase significantly. Considering energy conservation and production efficiency improvement, the best debittering effect is achieved by treating with a 10 kV electric field for 4 h.

[0111] (3) Effect of β-cyclodextrin solution concentration on limonin removal rate

[0112] It can be seen from Figure 5 that the β-cyclodextrin solution concentration is positively correlated with the limonin removal rate, and the best debittering effect is achieved by soaking in a 2.5% β-cyclodextrin solution.

[0113] (4) Limonin removal rate of different composite debittering methods

[0114] It can be seen from Figure 6It can be seen that the defluorination effect of the disodium ethylenediaminetetraacetate solution combined with the β-cyclodextrin solution group (EDTA-2Na + β-CD) is better than that of the electric field combined with the β-cyclodextrin solution group (EF + β-CD), and is further better than that of the electric field combined with the disodium ethylenediaminetetraacetate solution treatment group (EF + EDTA-2Na) and the disodium ethylenediaminetetraacetate solution combined with the electric field treatment group (EDTA-2Na + EF). This shows that the defluorination effects of the three methods alone are as follows: β-cyclodextrin solution > disodium ethylenediaminetetraacetate solution > high-voltage electric field.

[0115] Moreover, changing the order of the disodium ethylenediaminetetraacetate solution and the electric field treatment will also affect the defluorination effect. Specifically, using the electric field treatment first will reduce the defluorination effect.

[0116] In terms of the comprehensive effect, the combined use of the three methods has the highest limonin removal rate, indicating that the combined action of the three methods has a synergistic effect.

[0117] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for debittering frozen pomelo cysts, characterized in that: The pomelo cysts are soaked in a disodium ethylenediaminetetraacetic acid solution with a mass concentration of 0.5-2.5% for 15-75 minutes and then frozen to obtain debittered frozen pomelo cysts.

2. The method for debittering frozen pomelo cysts according to claim 1, characterized in that: The following steps are involved: S1. Soaking the grapefruit cysts in a 0.5-2.5% disodium ethylenediaminetetraacetic acid solution for 15-75 minutes; S2. freezing and thawing the grapefruit cysts treated in S1; S3. The thawed grapefruit cysts are soaked in a β-cyclodextrin solution to obtain debittered grapefruit cysts.

3. The method for debittering frozen pomelo cysts according to claim 2, characterized in that: The following steps are involved: S1. Soaking the grapefruit cysts in a 0.5-2.5% disodium ethylenediaminetetraacetic acid solution for 15-75 minutes; S2. The grapefruit cysts treated in S1 are placed in a 2.5-30KV high voltage electric field for 0.5-6h, and then frozen and thawed; S3. The thawed grapefruit cysts are soaked in a β-cyclodextrin solution to obtain debittered grapefruit cysts.

4. The method for debittering frozen pomelo cysts according to any one of claims 1 to 3, characterized in that: The concentration of the disodium edetate solution is preferably 1-2%, more preferably 1.5%.

5. The method for debittering frozen pomelo cysts according to any one of claims 1 to 3, characterized in that: The soaking time of the disodium ethylenediaminetetraacetic acid solution is preferably 30-60 minutes, more preferably 30 minutes.

6. The method for debittering frozen pomelo cysts according to claim 3, characterized in that: The voltage of the high-voltage electric field is preferably 10-30 KV, more preferably 10 KV; the treatment time of the high-voltage electric field is preferably 4-6 h, more preferably 4 h.

7. The method for debittering frozen pomelo cysts according to claim 2 or 3, characterized in that: The mass concentration of the β-cyclodextrin solution is 0.5-2.5%, and the soaking time of the β-cyclodextrin solution is not less than 30 minutes.

8. Use of disodium ethylenediaminetetraacetate as or in the preparation of an inhibitor of limonin D-ring lactone hydrolase.

9. Use of disodium ethylenediaminetetraacetate in removing limonin or debittering frozen grapefruit cysts, or in preparing a debittering preparation for limonin.

10. A composition for inhibiting the activity of limonin D-ring lactone hydrolase and / or removing limonin and / or for debittering frozen grapefruit cysts, characterized in that: The composition comprises disodium edetate and beta-cyclodextrin used separately; preferably, the disodium edetate is in the form of a solution with a mass concentration of 0.5-2.5%.

Images