A method for preparing Iota carrageenan

Abstract

This invention discloses a method for preparing Iota carrageenan. Using *Euphorbia tirucalli* as raw material, the raw material is washed to remove salt and sand, then alkali-modified in a potassium hydroxide solution. After acid neutralization, the raw material is directly soaked, ground, and ultrasonically extracted. The extract is then homogenized and finely filtered. A calcium chloride coagulant solution is added, and after mixing, only ethanol is added for dehydration. The precipitate is granulated, dried at low temperature, and pulverized to obtain high-yield, high-viscosity pure Iota carrageenan. This invention employs ultrasonic extraction technology, significantly improving the extraction rate of Iota carrageenan. The potassium salt formed during neutralization saves process water and provides a coagulant for the subsequent coagulation process. Furthermore, the addition of a low concentration of calcium chloride for coagulation greatly reduces the amount of ethanol used in traditional dehydration processes. This invention represents a novel, low-energy-consumption, high-yield, green extraction process for Iota carrageenan with broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of carrageenan production, and specifically to an efficient and green production process for Iota carrageenan. Background Technology

[0002] Carrageenan, also known as carrageenan gum, is a class of high-molecular-weight, water-soluble, heterogeneous polysaccharides containing sulfate ester groups extracted from seaweeds of the genera *Chlorella*, *Euphorbia*, *Cephalotaxus*, and *Sargassum* in the family Rhodophyceae. It is composed of alternating (1→3)-β-D-galactopyranose and (1→4)-α-D-galactopyranose repeating disaccharide units as its basic backbone. Based on differences in the number and number of sulfate groups on the D-galactose in the repeating disaccharides, as well as the presence or absence of dehydrated structures, carrageenan can be classified into more than ten types, but the most common types are mainly κ, ι, and λ.

[0003] The main source of Iota carrageenan is Euphorbia milii ( Eucheuma spinosum ), Qiongzhi Qilin Cai ( Eucheuma gelatinum ) and fine-toothed Euphorbia ( Eucheuma denticulatum Iota carrageenan is widely cultivated in the Philippines, Indonesia, Tanzania, and other regions. Compared to other types of carrageenan, it exhibits excellent gelling properties in salt solutions, including softness and elasticity, and strong stability. Furthermore, its unique sulfated polysaccharide structure gives it significant antiviral activity, and it has been formulated into a nasal spray for clinical use. This indicates that Iota carrageenan has broad application prospects and enormous development potential in the fields of food, cosmetics, biomedicine, and clinical applications.

[0004] Currently, the pretreatment process for Iota carrageenan generally includes alkali modification. However, the subsequent neutralization process in traditional extraction methods typically involves rinsing with large amounts of water or neutralizing with acid and then discarding the supernatant, both of which consume significant amounts of process water, greatly increasing the production and energy burden. Furthermore, traditional processes mostly employ hot extraction, which is time-consuming, energy-intensive, has low yield, and produces poor purity. In addition, the alcohol precipitation and dehydration process for polysaccharides often uses 3-4 times the volume of alcohol as in traditional methods, resulting in huge ethanol consumption and a high tendency for sol-gel formation, leading to high production costs.

[0005] Therefore, improving the production process of Iota carrageenan, reducing production costs, and achieving green and efficient extraction are of practical significance for accelerating the industrialization of Iota-type carrageenan. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing Iota carrageenan to overcome the shortcomings of the prior art.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A method for preparing Iota carrageenan includes the following steps:

[0009] (1) Clean the raw material, Euphorbia milii, remove impurities, dry and crush it;

[0010] (2) Weigh the algae powder and add it to the alkaline solution for modification;

[0011] (3) Add acid to neutralize and adjust the pH;

[0012] (4) The neutralized system was subjected to ultrasonic extraction;

[0013] (5) Heating and homogenizing;

[0014] (6) Filter while hot to obtain primary carrageenan solution;

[0015] (7) Add CaCl2 solution to the adhesive solution obtained in step (6);

[0016] (8) Iota carrageenan precipitate was obtained after final dehydration.

[0017] Furthermore, the raw material cleaning solution in step (1) is the production water specified in the pharmacopoeia, and the cleaning is performed three times. The *Euphorbia milii* can be *Euphorbia milii* var. *fine-toothed*. Eucheuma denticulatum Spiny seaweed Eucheuma spinosum Qiongzhi Qilin Cai ( Eucheuma gelatinum Natural red algae such as Euphorbia milii are washed, dried, and then pulverized to obtain algae powder, which is then crushed to about 200 mesh.

[0018] Furthermore, the alkaline solution in step (2) is a potassium hydroxide solution with a mass concentration of 3-10%. The raw material and the potassium hydroxide solution are modified with alkali at a solid-liquid ratio of 1:30, and the modification time is 1-3 h.

[0019] Furthermore, the neutralizing substance in step (3) can be a variety of acid solutions, including but not limited to hydrochloric acid, and the pH of the neutralized solution can be controlled within the range of 7.00-8.50.

[0020] Furthermore, the ultrasonic extraction system in step (4) includes a neutralized liquid and algae, with a solid-liquid ratio of 1:30-1:40, an ultrasonic power of 50-500W, an ultrasonic frequency of 40KHz, an ultrasonic extraction time of 5-30min, and an ultrasonic temperature of 55-95℃.

[0021] Furthermore, the homogenization conditions in step (5) are uniform stirring at 65-95℃ for 0.5-2h.

[0022] Furthermore, the calcium chloride solution in step (7) is a coagulant aid, added at a volume ratio of 1:10 (V / L). 氯化钙 :V胶液 (), until the system mass concentration is 0.50%-2.00%.

[0023] Furthermore, in step (8), the industrial ethanol is used as a dehydrating agent. One volume of industrial ethanol is added to the calcium gel solution, mixed evenly, and then centrifuged at 4°C for 0.5-4 h to obtain carrageenan precipitate.

[0024] Furthermore, the method for preparing Iota carrageenan also includes granulating the obtained Iota carrageenan precipitate, drying it at low temperature, and pulverizing it.

[0025] The advantages and beneficial effects of this invention are as follows:

[0026] (1) The present invention uses washed and ground algae powder for alkali modification. The reaction time is only 1-3 hours to inhibit the precursor form, remove the wax layer on the surface of the seaweed and improve the gel strength. Compared with the traditional overnight soaking alkali treatment, the present invention significantly saves the pretreatment time and avoids the disadvantages of damaging the algal cell wall due to long-term alkali modification, resulting in sol and reduced yield.

[0027] (2) The neutralization after alkali modification in this invention does not employ the traditional process of washing with large amounts of water to neutralize, nor does it involve adding acid to adjust the pH to neutral and then discarding the supernatant. Instead, the neutralized solution is directly reused in the subsequent ultrasonic extraction. While saving a large amount of process water, this invention fully utilizes the potassium salt generated during neutralization, providing a potential coagulant aid for the subsequent coagulation of the gel. Furthermore, since the soaking of the algal water system inevitably leads to the presence of potential gel in the neutralized solution, this invention avoids the yield loss caused by this process.

[0028] (3) The present invention uses ultrasonic extraction technology, which greatly shortens the extraction time and significantly improves the yield compared with the traditional Iota carrageenan preparation method; at the same time, the viscosity, strength and other gel properties of the product are significantly improved and the amount of heat energy consumed is reduced.

[0029] (4) In addition to making full use of the potassium salt present in the pretreatment of the adhesive, the present invention also adds a low concentration of calcium chloride as a coagulant. Compared with the traditional overnight dehydration reaction of 3-4 times ethanol, the present invention only requires one volume of industrial ethanol, and the dehydration reaction only takes about 1 hour, which greatly reduces the amount of ethanol used in the traditional dehydration process and saves preparation time.

[0030] (5) Compared with traditional processes, the present invention shortens the overall preparation time of Iota carrageenan and through 13 C NMR spectroscopy verification shows that the Iota carrageenan prepared by this invention has a significantly higher purity than commercially available products, providing a high-quality, high-purity, green, and efficient extraction process for Iota carrageenan. Attached Figure Description

[0031] Figure 1 The nuclear magnetic resonance carbon spectra of the product of this invention and commercially available products ( 13 C NMR comparison spectrum. Detailed Implementation

[0032] The technical solution of the present invention will be further described in detail below through specific examples.

[0033] The reagents used in this invention are all commercially available products and can be purchased on the market.

[0034] In the following examples, the viscosity was determined as follows: Iota carrageenan product was accurately weighed according to the ratio of 1.5 g carrageenan / 100 mL water, stirred thoroughly at 80°C until completely dissolved, cooled to about 75°C, and the viscosity was measured using an NDJ-8S digital viscometer or a rotational viscometer with equivalent measurement effect, after selecting a suitable rotor and speed. The same sample was measured three times consecutively, and the average value was taken.

[0035] In the following examples, the gel strength was determined as follows: a KCl solution was prepared at a ratio of 0.2 g / 100 mL water, and Iota carrageenan product was accurately weighed at a ratio of 1.5 g carrageenan / 100 mL KCl solution. The mixture was stirred thoroughly at 80-90°C until completely dissolved, and then poured into a mold while hot to set. After it had completely solidified, the gel strength was determined using a TMS-TOUCH property analyzer.

[0036] In the following examples, carbon nuclear magnetic resonance spectroscopy analysis (NMR spectroscopy) 13 The determination method for C NMR is as follows: 30 mg each of the carrageenan used in this invention and commercially available carrageenan were exchanged three times with D2O (99.95%) to replace the active protons in the polysaccharide, and finally dissolved in 600 μL of D2O. The sample was measured at 298 K using a Bruker BioSpin GmbH 600-MHz instrument. 13 C10 NMR spectrum. With 3-trimethylsilylpropanesulfonic acid (DSS) as an internal standard, its chemical shift is 0.00 ppm.

[0037] Example 1

[0038] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 5 g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液The solution was added to a 5% KOH solution at a ratio of 1:10 (V / L). Alkali modification was performed for 2 hours, followed by acid neutralization to pH 7.06. The mixture was then ultrasonically extracted at 60℃ for 15 minutes, and finally homogenized in a 95℃ water bath for 1 hour. The solution was obtained by hot filtration and then mixed with the solution at a volume ratio of 1:10 (V / L). 氯化钙 :V 胶液 Add calcium chloride solution as a coagulant in the proportion of 0.75%, mix well, and immediately add 95% ethanol at a volume equal to one volume. Stir well, place in a 4°C refrigerator for dehydration for 1 hour, filter, and granulate the resulting gel block. Dry at low temperature and pulverize to obtain Iota carrageenan powder.

[0039] The Iota carrageenan obtained in this embodiment had a yield of 52.73%, a viscosity of 722.33 mPa / s, and a gel strength of 138.72 g / cm³. 2 .

[0040] Example 2

[0041] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 5 g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液 The mixture was added to a 5% KOH solution at a ratio of 1:10 (V / L) and subjected to alkali modification for 2 hours. After neutralization to pH 8.33, it was ultrasonically extracted at 60℃ for 20 minutes, then transferred to an 85℃ water bath and stirred for 1 hour for homogenization. The solution was obtained by hot filtration and then mixed at a volume ratio of 1:10 (V / L). 氯化钙 :V 胶液 Add calcium chloride solution as a coagulant in the proportion of 0.75%, mix well, and immediately add 95% ethanol at a volume equal to one volume. Stir well, place in a 4°C refrigerator for dehydration for 1 hour, filter, and granulate the resulting gel block. Dry at low temperature and pulverize to obtain Iota carrageenan powder.

[0042] The Iota carrageenan obtained in this embodiment had a yield of 44.89%, a viscosity of 777.67 mPa / s, and a gel strength of 161.16 g / cm³. 2 .

[0043] Example 3

[0044] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 5 g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液 The mixture was added to a 5% KOH solution at a ratio of 1:10 (V / L) and subjected to alkali modification for 2 hours. After neutralization to pH 8.36, it was ultrasonically extracted at 60℃ for 18 minutes, then transferred to a 90℃ water bath and stirred for 1 hour for homogenization. The solution was obtained by hot filtration and then mixed at a volume ratio of 1:10 (V / L). 氯化钙 :V胶液 Add calcium chloride solution as a coagulant in the proportion of 0.75%, mix well, and immediately add 95% ethanol at a volume equal to one volume. Stir well, place in a 4°C refrigerator for dehydration for 1 hour, filter, and granulate the resulting gel block. Dry at low temperature and pulverize to obtain Iota carrageenan powder.

[0045] The Iota carrageenan obtained in this embodiment had a yield of 48.36%, a viscosity of 788.67 mPa / s, and a gel strength of 146.88 g / cm³. 2 .

[0046] Example 4

[0047] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 5 g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液 The mixture was added to a 5% KOH solution at a ratio of 1:10 (V / L) and subjected to alkali modification for 2 hours. After neutralization to pH 8.19, it was ultrasonically extracted at 60℃ for 20 minutes, then transferred to a 95℃ water bath and stirred for 1 hour for homogenization. The solution was obtained by hot filtration and then mixed at a volume ratio of 1:10 (V / L). 氯化钙 :V 胶液 Add calcium chloride solution as a coagulant in the proportion of 0.70%, mix well, and immediately add 95% ethanol at a volume equal to one volume. Stir well, place in a 4°C refrigerator for dehydration for 1 hour, filter, and granulate the resulting gel blocks. Dry at low temperature and pulverize to obtain Iota carrageenan powder.

[0048] The Iota carrageenan obtained in this embodiment had a yield of 44.07%, a viscosity of 781.67 mPa / s, and a gel strength of 148.92 g / cm³. 2 .

[0049] Example 5

[0050] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 5 g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液 The solution was added to a 5% KOH solution at a ratio of 1:10, and the mixture was alkali-modified for 1.5 hours, neutralized to pH 7.89, and ultrasonically extracted at 60℃ for 18 minutes. Then, it was transferred to a 90℃ water bath and stirred for 1 hour for homogenization. The solution was obtained by hot filtration and then mixed at a volume ratio of 1:10 (V / L). 氯化钙 :V 胶液 Add calcium chloride solution as a coagulant in the proportion of 0.75%, mix well, and immediately add 95% ethanol at a volume equal to one volume. Stir well, place in a 4°C refrigerator for dehydration for 1 hour, filter, and granulate the resulting gel block. Dry at low temperature and pulverize to obtain Iota carrageenan powder.

[0051] The Iota carrageenan obtained in this embodiment had a yield of 46.83%, a viscosity of 778.67 mPa / s, and a gel strength of 138.72 g / cm³. 2 .

[0052] Example 6

[0053] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 5 g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液 The solution was added to a 5% KOH solution at a ratio of 1:10 (V / L). Alkali modification was performed for 2 hours, followed by acid neutralization to pH 7.22. The mixture was then ultrasonically extracted at 60℃ for 18 minutes, and finally homogenized in a 90℃ water bath for 1 hour. The solution was obtained by hot filtration and then mixed at a volume ratio of 1:10 (V / L). 氯化钙 :V 胶液 Add calcium chloride solution as a coagulant at a concentration of 0.80% to the mixture. After mixing evenly, immediately and slowly add an equal volume of 95% ethanol. Stir evenly and place in a 4°C refrigerator for dehydration for 1 hour. Filter the mixture. Granulate the resulting gel blocks, dry them at low temperature, and pulverize them to obtain Iota carrageenan powder.

[0054] The Iota carrageenan powder obtained in this embodiment, after testing, had a yield of 46.11%, a viscosity of 775.33 mPa / s, and a gel strength of 181.56 g / cm³. 2 .

[0055] Comparative Example 1 (Iota carrageenan extracted using traditional methods)

[0056] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 3 g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液 The material was added to a 5% KOH solution at a ratio of 1:30, and soaked overnight for alkali modification. It was then rinsed repeatedly with tap water until the solution was neutral. Water was added at 80°C and the solution was boiled for 2 hours at a ratio of 1:30. The mixture was filtered and repeated twice. The solutions were combined and then industrial ethanol was added to the filtrate at a ratio of 1:4 (V:V) for alcohol precipitation. The resulting rubber blocks were dried and crushed to obtain Iota carrageenan powder.

[0057] The Iota carrageenan powder obtained in this comparative example had a yield of 16.77%, a viscosity of 304.67 mPa / s, and a gel strength of 85.68 g / cm³. 2 .

[0058] The comparison results of the parameters of the above embodiments and comparative examples are shown in Table 1.

[0059] Table 1. Quality Comparison of Iota Carrageenan

[0060] Product Name Yield % Viscosity mPa / s <![CDATA[Gel strength g / cm 2 > Example 1 52.73 722.33 138.72 Example 2 44.89 777.67 161.16 Example 3 48.36 788.67 146.88 Example 4 44.07 781.67 148.92 Example 5 46.83 778.67 138.72 Example 6 46.11 775.33 181.56 Comparative Example 1 16.77 304.67 85.68

[0061] The results showed that, compared with the traditional process, the Iota carrageenan powder prepared by the present invention had a yield of over 40%, and the production efficiency was greatly improved; in terms of product performance, compared with the traditional products, the product of the present invention had significant improvements in viscosity and gel strength.

[0062] Comparative Example 2

[0063] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 5g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液 The solution was added to a 5% KOH solution at a ratio of 1:10 (V / L). Alkali modification was performed for 2 hours, followed by acid neutralization to a pH of 7.72. The mixture was then ultrasonically extracted at 45°C for 20 minutes, and finally homogenized in a 90°C water bath for 1 hour. The solution was obtained by hot filtration and then mixed with the solution at a volume ratio of 1:10 (V / L). 氯化钙 :V 胶液 Add calcium chloride solution as a coagulant in the proportion of 0.75%, mix well, and immediately add 95% ethanol at a volume equal to one volume. Stir well, place in a 4°C refrigerator for dehydration for 1 hour, filter, and granulate the resulting gel block. Dry at low temperature and pulverize to obtain Iota carrageenan powder.

[0064] The Iota carrageenan powder obtained in this comparative example had a yield of 28.54% and a viscosity of 557.67 mPa / s. This indicates that lowering the ultrasonic extraction temperature significantly affects the extraction rate of Iota carrageenan and reduces the product viscosity.

[0065] Comparative Example 3

[0066] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 5 g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液 The solution was added to a 5% KOH solution at a ratio of 1:10 (V / L). Alkali modification was performed for 2 hours, followed by acid neutralization to pH 8.05. The mixture was then ultrasonically extracted at 60℃ for 40 minutes, and finally homogenized in a 90℃ water bath for 1 hour. The solution was obtained by hot filtration and then mixed with the solution at a volume ratio of 1:10 (V / L). 氯化钙 :V 胶液 Add calcium chloride solution as a coagulant in the proportion of 0.75%, mix well, and immediately add 95% ethanol at a volume equal to one volume. Stir well, place in a 4°C refrigerator for dehydration for 1 hour, filter, and granulate the resulting gel block. Dry at low temperature and pulverize to obtain Iota carrageenan powder.

[0067] The Iota carrageenan powder obtained in this comparative example had a yield of 33.97% and a viscosity of 661.33 mPa / s. Therefore, it can be seen that the extraction rate of Iota carrageenan actually decreases after exceeding the appropriate ultrasonic extraction time.

[0068] Comparative Example 4

[0069] The original algae, namely *Euphorbia tirucalli* from Tanzania, was washed, dried, and pulverized into algae powder for later use. Weigh 5 g of the algae powder and mix it with water at a ratio of 1:30 (W... 麒麟菜 V 碱液 The solution was added to a 5% KOH solution at a ratio of 1:10 (V / L). Alkali modification was performed for 2 hours, followed by acid neutralization to a pH of 7.79. The mixture was then ultrasonically extracted at 60°C for 18 minutes, and finally homogenized in a 90°C water bath for 1 hour. The solution was then filtered while hot to obtain the gel. 氯化钙 :V 胶液 Add calcium chloride solution as a coagulant at a concentration of 0.45% to the mixture. After mixing evenly, immediately and slowly add an equal volume of 95% ethanol. Stir evenly and place in a 4°C refrigerator for dehydration for 1 hour. Filter the mixture. Granulate the resulting gel blocks, dry them at low temperature, and pulverize them to obtain Iota carrageenan powder.

[0070] The Iota carrageenan powder obtained in this comparative example had a yield of 41.87% and a viscosity of 470.67 mPa / s. The product color was significantly darker, and the liquid sample appeared distinctly turbid during viscosity testing. This indicates that the addition of low-concentration filter aids has a significant impact on product quality, and the filter aid concentration should be maintained within a reasonable range.

[0071] Comparative Example 5

[0072] Iota carrageenan was purchased commercially available and its carbon NMR spectrum was compared with that of the product of this invention. 13 Comparative analysis of CNMR.

[0073] The product of this invention has a carbon NMR spectrum similar to that of commercially available products. 13 The C NMR comparison spectrum is as follows: Figure 1 As shown.

[0074] Carbon NMR spectrum of Iota carrageenan ( 13 In C NMR, the strong signal in the δ 110-94 ppm range represents the anodic carbon signal in the repeating unit structure of Iota carrageenan. Specifically, the strong signal in the δ 104.98-104.43 ppm range is the characteristic peak of ι G4S-C1, the strong signal at δ 94.32 ppm is the characteristic peak of ι DA2S-C1, and the strong signal at δ 96.67 ppm is generally considered to be the characteristic peak of Kappa-type carrageenan (κ DA-C1).13 In a C10 NMR spectrum, this peak is generally considered an impurity peak / strong interference peak. It should be noted that other strong signals in the δ 110-94 ppm range are generally considered to be impurity peaks of other types of colloids. The more impurity peaks and the stronger the signal, the lower the purity of the Iota carrageenan in the sample.

[0075] The results show that the product of this invention 13 The C NMR spectrum shows peaks that generally meet the requirements. Strong signals appear at δ 104.98 ppm and δ 94.32 ppm, representing the characteristic peaks of ι G4S-C1 and ι DA2S-C1, respectively. This indicates that the Iota carrageenan product produced by this invention, while improving yield and product performance, has not undergone significant structural changes, and its production process has not introduced other impurities. Compared with commercially available products, the Iota carrageenan product produced by this invention, in the 110-90 ppm range, has no other characteristic peaks interfering except for the two sharp peaks unique to Iota carrageenan, ι G4S-C1 and ι DA2S-C1, indicating better purity. In contrast, the spectrum of commercially available products shows a distinct κ DA-C1 impurity peak at δ 96.54 ppm (κ at δ 71.67 ppm). The appearance of the DA-C2 peak (which corroborates this finding) and the presence of numerous unknown impurity peaks in the overall spectrum indicate significant impurity interference. This suggests that the commercially available Iota carrageenan standard has poor purity and is subject to various colloidal interferences.

[0076] In summary, compared with traditional processes, the Iota carrageenan product produced by this invention has excellent yield and gelation properties. The process of this invention is simple, environmentally friendly, has a short production cycle, and uses safe and widely available raw materials, greatly reducing the waste of water resources, heat energy, and industrial ethanol during the extraction process. It is a novel, low-energy-consumption, high-yield green extraction process for Iota carrageenan with broad application prospects.

[0077] It should be noted that although some embodiments of the present invention have been given and described above, it is understood that the above embodiments are merely exemplary examples and should not be construed as limiting the present invention. Any simple modifications, equivalent changes and alterations made to the present invention without departing from the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing Iota carrageenan, characterized in that, The preparation method includes the following steps: (1) Clean the raw material, Euphorbia milii, remove impurities, dry and crush it; (2) Weigh the algae powder into the alkaline solution for modification; the alkaline solution is a potassium hydroxide solution with a mass concentration of 3-10%, and the raw material and potassium hydroxide solution are modified with an alkaline ratio of 1:30, and the modification time is 1-3 hours. (3) Add acid to neutralize and adjust the pH; (4) The neutralized system is subjected to ultrasonic extraction; wherein the ultrasonic extraction system includes the neutralized liquid and algae, the solid-liquid ratio is 1:30-1:40, the ultrasonic power is 50-500W, the ultrasonic frequency is 40KHz, the ultrasonic extraction time is 5-30min, and the ultrasonic temperature is 55-95℃. (5) Heat and homogenize, and the homogenization conditions are uniform stirring at 65-95℃ for 0.5-2h; (6) Filter while hot to obtain primary carrageenan solution; (7) Add CaCl2 solution to the adhesive solution obtained in step (6); calcium chloride solution is a coagulant aid, added at a volume ratio of 1:10, until the mass concentration of the system is 0.70%-2.00%; (8) Iota carrageenan precipitate was obtained after final dehydration.

2. The method for preparing Iota carrageenan as described in claim 1, characterized in that, In step (3), an acid solution is used for neutralization, and the pH of the neutralized solution is controlled within the range of 7.00-8.

50.

3. The method for preparing Iota carrageenan as described in claim 1, characterized in that, In step (8), industrial ethanol is used as a dehydrating agent. One volume of industrial ethanol is added to the calcium gel solution, mixed evenly, and then centrifuged at 4°C for 0.5-4 hours to obtain carrageenan precipitate.

4. The method for preparing Iota carrageenan as described in claim 1, characterized in that, The method for preparing Iota carrageenan also includes granulating the obtained Iota carrageenan precipitate, drying it at low temperature, and pulverizing it.

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