A carrageenan and carrageenan-based GEL and method of producing the same and use thereof

Abstract

The present invention relates to a carrageenan, comprising sodium ions, wherein the sodium ions are in an amount of 1-10%w / w, or 2-6%w / w based on the carrageenan, wherein when 1%w / w of carrageenan is dissolved in water to form a carrageenan solution, pH of the carrageenan solution is in a range of 5-9, 7-9, or 7.8-9, wherein hydrogen ions, and the sodium ions are combined with sulfuric acid groups of the carrageenan to form carrageenan-sulfuric hydrogen and carrageenan-sulfuric sodium, respectively. The present invention also related to a carrageenan-based gel, comprising the carrageenan discussed, starch, a first salt, glycerine and water.

Description

A CARRAGEENAN AND CARRAGEENAN-BASED GEL AND METHOD OF PRODUCING THE SAME AND USE THEREOFCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Chinese Application No. 202410105229.5, filed January 25, 2024, the disclosure of which is incorporated by reference herein in its entirety.FIELD OF THE INVENTION

[0002] The present invention relates to the technical field of carrageenan-based gel, in particular a capsule film comprising carrageenan-based gel.BACKGROUND

[0003] In recent years, natural, healthy and green plant-based soft capsules have become a hot spot in the market. Compared with animal-derived soft capsules, plant-based soft capsules have a wider application market, adapting to consumer groups including halal, vegetarian, kosher and other eating habits. In the future, with the national health awareness increasing as well as the vegetarian consumer groups expanding, the plant-based soft capsules would have greater development potential in the market.

[0004] However, the common carrageenan on the market has high viscosity and high gelling temperature when used in soft capsules. There are lots of disadvantages for the common carrageenan in the market, such as high requirements for manufacturing equipment, poor reversibility, poor reuse of gel-film and high cost.

[0005] The existing solutions in the art relate to reducing the molecular weight (Mw) of carrageenan to reduce its viscosity and gelling temperature, such as US patent 7816341. In Europe, the wording “carrageenan” is reserved for the non-hydrolyzed or chemically degraded polymer (i.e. poligeenan). Concern has been raised about the amount of material in carrageenan with molar mass less than 50,000 Da (poligeenan). Some studies have shown that reducing the molecular weight of carrageenan has health risks. For example, reducing Mw by degrading carrageenan (poligeenan) may cause the concerned risk of gastrointestinal ulcers and gastrointestinal cancers.

[0006] Therefore, there are needs in the market to provide a carrageenan-based gel without the need to reduce the Mw of carrageenan.SUMMARY

[0007] The present invention relates to a carrageenan, comprising sodium ions, wherein the sodium ions are in an amount of l-10%w / w, or 2-6% w / w based on the carrageenan, wherein when l%w / w of carrageenan is dissolved in water to form a carrageenan solution, pH of the carrageenan solution is in a range of 5-9, 7-9, or 7.8-9, wherein hydrogen ions, and the sodium ions are combined with sulfuric acid groups of the carrageenan to form carrageenansulfuric hydrogen and carrageenan-sulfuric sodium, respectively.

[0008] The present invention relates to a carrageenan-based gel, comprising a carrageenan, a starch preferably a modified starch, a first salt, glycerin and water, wherein the carrageenan comprises sodium ions, and the sodium ions are in an amount of l-10%w / w, or preferably 2- 6%w / w based on the carrageenan, wherein when l%w / w of carrageenan is dissolved in water to form a carrageenan solution, pH of the carrageenan solution is in a range of 5-9, 7-9. or 7.8-9, and wherein hydrogen ions, and the sodium ions are combined with sulfuric acid groups of the carrageenan to form carrageenan-sulfuric hydrogen and carrageenan-sulfuric sodium, respectively.

[0009] The present invention relates to use of the carrageenan or the carrageenan- based gel discussed in a soft capsule film.

[0010] The present invention relates to a method of producing carrageenan, comprising: (a) gelificating a pulp of seaweed preferably by KC1 to obtain a crude carrageenan: (b) applying a solution to the crude carrageenan to obtain the carrageenan, wherein the solution comprises an acid, preferably an organic acid, a second salt other than potassium salts and calcium salts, and alcohol, and the method does not reduce the molecular weight of carrageenan.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 shows the conversion of colloids to gel I and further to gel II and their reversibility.

[0012] Figure 2 shows a schematic diagram of procedures of preparing carrageenan.DETAILED DESCRIPTION

[0013] Unless otherwise noted, all measurements, weights, lengths etc. are in metric units, and all temperatures are in degrees Celsius. It is understood that unless otherwise specifically noted, the materials compounds, chemicals, etc. described herein are typically commodity items and / or industry-standard items available from a variety of suppliers and sources worldwide.

[0014] Throughout this document, values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “about 0.1% to about 5%'’ or “about 0.1-5 %’’ should be interpreted to include not just about 0.1 to about 5 %. but also the individual values (e g.1%, 2%, 3% and 4%) and the sub-ranges (e.g. 0. 1 %-0.5%, 1. l%-2.2%, 3.3%-4.4%) within the indicated range. And for example, “95-121°C” not only includes 95-121°C but also the individual values (e g. 95 °C, 96 °C, 97°C, etc.) and the sub-ranges (e.g. 95-97°C, 96-100°C, 100-121°C) within the indicated range. For example, a range of “C2-C16” should be interpreted to include C2, C3, C4. C5... Cl 4, Cl 5, and Cl 6. The statement “about X to Y” has the same meaning as “about X to about Y”, unless indicated otherwise. Likewise, the statement “about X, Y or about Z” has the same meaning as “about X, about Y or about Z”, unless indicated otherwise.

[0015] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, reference to "a substituent" encompasses a single substituent as well as two or more substituents, and the like. It is understood that any term in the singular may include its plural counterpart and vice versa.

[0016] The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B" has the same meaning as “A, B. or A and B.”

[0017] As used herein, the terms "for example, "for instance,” "such as," “e.g.,” or "including" are meant to introduce examples that further clarify more general subject matter. Unless otherwise specified, these examples are provided only as an aid for understanding the applications illustrated in the present disclosure and are not meant to be limiting in any fashion.

[0018] The term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 9%, within 8%, within 7%, within 6%, within 5%, within 4%, within 3%, within 2%, or within 1% of a stated value or of a stated limit of a range and includes the exact stated value or range.

[0019] The term “the average molecular weight of carrageenan greater than 500,000” means that the average molecular weight of carrageenan is greater than 500,000g / mol. The amountof carrageenan of Mw less than 50,000 Dalton is less than 10wt% or preferably less than 5wt% by weight of the carrageenan.

[0020] The term “at least a part” means 30% or above, 40% or above, 50% or above, 60% or above, 70% or above, 80% or above, 90% or above, or 100% of the substance.

[0021] The term “melting temperature” refers to the temperature at which a solid phase melts into a liquid phase, and in one embodiment, it refers to the temperature at which a gel / film turns into gel mass.

[0022] The term “setting temperature”, also known as “gelling temperature” or “gelling point”, refers to the temperature at which a liquid phase becomes a solid phase, and in one embodiment, it refers to the temperature at which gel mass turns into a gel / film. In one embodiment, the melting temperature is slightly higher than the setting temperature.

[0023] In one aspect, long chains of carrageenan molecules exist in the solution in the form of railless clusters. With cooling, a three-dimensional polymer network structure is first formed, and the hydrogen bond between galactose O-2 and O-6 is twisted into double spirochete, which generates the binding point of the polymer chain, i.e. forming gel I (helix) which has a preliminary gelatinous state. As shown in Figure 1, when carrageenan colloids are cooled down, carrageenan colloids would form into gel I and the gel strength of gel I would increase compared to carrageenan colloids. Further cooling of gel I would cause these binding sites to aggregate to form a double Spirochaeta bundle, forming a hard gel, i.e. forming gel II (aggregation).

[0024] In one aspect, cations such as potassium ions are removed or reduced from the carrageenan. Instead of potassium ions, hydrogen ions and sodium ions are introduced to carrageenan. In one aspect, introduction of hydrogen ions and sodium ions into carrageenan does not destroy the molecular structure and molecular weight of carrageenan, and at least a part of the hydrogen ions and at least of a part of the sodium ions are combined with sulfuric acid groups. In one aspect, in the presence of hydrogen ions and sodium ions, most of carrageenan is in the colloid form. This would maintain its reversibility at the same time and make it not easy to form gel II or carrageenan superstrands, so as to reduce the gelling temperature and viscosity' of a carrageenan- based gel or gel mass.

[0025] In one aspect, the presence of sodium ions can deter the coil-to-double helix conformational change of carrageenan, while the presence of potassium ions can promote a coil- to-double helix conformational change to the carrageenan.

[0026] In one aspect, a part of the hydrogen ions, and a part of the sodium ions are combined with sulfuric acid groups to form carrageenan-sulfuric hydrogen and carrageenansulfuric sodium, respectively. The remaining hydrogen ions and sodium ions are floating incarrageenan solution. In one aspect, all of the hydrogen ions and sodium ions are combined with sulfuric acid groups to form carrageenan-sulfuric hydrogen and carrageenan-sulfuric sodium, respectively.

[0027] In one aspect, the present invention provides a carrageenan (or a carrageenan-based gel) and a method of producing the same, in which hydrogen ions and sodium ions are introduced to the carrageenan without reducing the molecular weight of carrageenan and meanwhile to avoid / reduce forming into gel II. Introduction of hydrogen ions and sodium ions to carrageenan makes the viscosity and gelling temperature of the carrageenan-based gel / gel mass decrease to a level such that the carrageenan-based gel has properties that resemble the properties of gelatin.

[0028] The present invention provides a carrageenan which comprises sodium ions, wherein the sodium ions are in an amount of I-10%w / w, or 1 to 9%w / w, or 1 to 8%w / w. or 1 to 7%w / w, or 2 to 7%, w / w, or 2-6%w / w based on the carrageenan, wherein when l%w / w of carrageenan is dissolved in water to form a carrageenan solution, pH of the carrageenan solution is in a range of 5-9, 7-9, or 7.8-9, wherein hydrogen ions, and the sodium ions are combined with sulfuric acid groups of the carrageenan to form carrageenan-sulfuric hydrogen and carrageenansulfuric sodium, respectively.

[0029] In one aspect, the carrageenan is in a form of powder. In one aspect, the carrageenan comprises sodium ions and hydrogen ions. In one aspect, when the carrageenan is dissolved in aqueous solution, at least a part of the hydrogen ions and at least of a part of sodium ions are combined with sulfuric acid groups of the carrageenan. In one aspect, the remaining of hydrogen ions and sodium ions is present in the aqueous solution.

[0030] In one aspect, at least a part of the sodium ions and at least a part of the hydrogen ions are combined with sulfuric acid groups of the carrageenan. In one aspect, introduction of hydrogen ions and sodium ions would make it hard to form a bridge structure and thereby avoid or reduce forming gel I and a bundle of gel II (as shown in FIG. 1), allowing the carrageenan or carrageenan-based gel to be more suitable for e.g. soft capsule films.

[0031] In one aspect, carrageenan is derived from seaweeds, preferably from red seaweeds. In one aspect, carrageenan is K-carrageenan, r-carrageenan or its combination.

[0032] In one aspect, the amount of salt ions (such as potassium ions and calcium ions) other than sodium ions in the carrageenan is lower than 6%w / w, or lower than 5%, or lower than 4%, or lower than 3.8%w / w, or lower than 3%, or lower than l%w / w, or in a range of 0.1-6%w / w, or in a range of 0. l-5%w / w, or in a range of 0. l-4%w / w based on the carrageenan. In one aspect, the carrageenan has a low salt content other than sodium ions, such as lower than 6%w / w, or lowerthan 5%, or lower than 4%, or lower than 3.8%w / w, or lower than 3%, or lower than l%w / w, or in a range of 0.1-6%w / w, or in a range of 0.1-5%w / w or in a range of 0.1-4%w / w.

[0033] The present invention provides a carrageenan-based gel, comprising the carrageenan as described above. The carrageenan-based gel can further comprise additional ingredients, for example, starch, a first salt, glycerin and water. In one aspect, the carrageenan- based gel comprises 6-10wt% of carrageenan, 25-35wt% of starch (preferably modified starch), 0.5-1.5wt% of the first salt, and 15-25wt% of glycerin and water in an amount which makes all components add up to 100wt%. In one aspect, the carrageenan-based gel is obtained by mixing the carrageenan, starch, the first salt, glycerine and water.

[0034] In one aspect, the first salt comprises sodium phosphate. In one aspect, the starch comprises a modified starch. In one aspect, the modified starch comprises hydroxypropyl starches.

[0035] Molecular weight of carrageenan is measured by the method disclosed in Uno Y., et al., 2001 (Uno Y, Omoto T, Goto Y, Asai I, Nakamura M, Maitani T. Molecular weight distribution of carrageenans studied by a combined gel permeation / inductively coupled plasma (GPC / ICP) method. Food Addit Contain. 2001 Sep;18(9):763-72).

[0036] In one aspect, the average molecular weight of carrageenan in the carrageenan- based gel is greater than 500,000 g / mol, or preferably greater than 600,000 g / mol, or preferably greater than 700,000 g / mol. In one aspect, the average molecular weight of carrageenan in the carrageenan-based gel is in a range of 500,000-900,000 g / mol, or in a range of 600,000-900,000 g / mol. or in a range of 600,000-800.000 g / mol, or in a range of 500,000-800,000 g / mol. or in a range of 500,000-750,000 g / mol, or in a range of 620,000-745,000 g / mol.

[0037] In one aspect, carrageenan having a molecular weight of greater than 100,000g / mol in the carrageenan-based gel is at least 60% wt, or preferably at least 70%wt, or preferably at least 80%wt, or preferably at least 90%wt. or preferably at least 95%wt by weight of the carrageenan.

[0038] In one aspect, the molecular weight of carrageenan less than 50,000g / mol in the carrageenan-based gel is less than 1.0wt%, 0.75wt%, 0.73wt%, 0.70\\t%. or in a range of 0.1- 0.75wt% by weight of the carrageenan. In one aspect, the molecular weight of carrageenan less than 100,000 g / mol is less than 4wt%, 3.5wt%, 3 t%. or in a range of 2-4wt% by weight of the carrageenan.

[0039] In one aspect, all ingredients in the carrageenan-based gel are dissolved and stirred at high speed under pressure to reach a final temperature of 90°C, and the gelling temperature and viscosity are measured using an equipment called HAAKE viscotester IQ. The rotor is P60. The gelling temperature and viscosity were measured by an Oscillation temperature ramp which the temperature is set from 100°C and decreased to 50°C with a frequency at 1Hz and shear stress atIPa. The viscosity at 90°C is read. The temperature at the point where storage modulus equals to loss modulus is read as the gelling temperature.

[0040] In one aspect, the viscosity of carrageenan-based gel mass at 90°C is lower than l,800,000cPs, or lower than l,500,000cPs, or lower than l,300,000cPs, or lower than l,000,000cPs, or lower than 800,000cPs, or lower than 600,000cPs, or lower than 500,000cPs, or lower than 400,000cPs, or lower than 300,000cPs. The viscosity of gel mass at 90°C is in a range of 100, 000-1.800, OOOcPs, or in a range of 100, 000-1.500.000cPs, or in a range of 100,000- l,300,000cPs, or in a range of 200, 000-1, 300, OOOcPs, or in a range of 200, 000-1, 000,000cPs, or in a range of 200,000-1, 100, OOOcPs, or in a range of 200, 000- 1,000, OOOcPs, or in a range of 200, 000-800, OOOcPs.

[0041] In one aspect, the gelling temperature of carrageenan-based gel mass is in a range of 40-75°C, or 40-70°C, or 40-65°C, or 45-70°C, or 40-65°C or 45-60°C or 40-60°C, or 40-50°C, or 50-60°C, or 45-55°C.

[0042] In one aspect, the present invention provides use of the carrageenan or the carrageenan-based gel in a capsule film. In one aspect, the capsule is a soft capsule. In one aspect, the capsule is used for medicine, cosmetics, or food. In one aspect, the capsule film comprises the carrageenan-based gel, and optionally further comprises a bulking agent (such as starch, cellulose), and a plasticizer (such as polyols e.g. glycerin, sorbitol, or starch).

[0043] In one aspect, the present invention provides a method of producing carrageenan, comprising: (a) gelificating a pulp of seawead preferably by KC1 to obtain a crude carrageenan; (b) applying a solution to the crude carrageenan to obtain the carrageenan, wherein the solution comprises an acid (preferably organic acid), a second salt other than potassium salts and calcium salts (preferably a sodium salt), and alcohol. The method reduces the average molecular weight by less than 40% relative to the average molecular weight of the carrageenan without the sodium salt, or by less than 30%, or less than 20%, or less than 15%, or less than 10%, or less than 5%, or less than 3% relative to the average molecular weight of the carrageenan without the sodium salt. Preferably, the method does not reduce the average molecular weight of carrageenan relative to the average molecular weight of carrageenan without the sodium salt. Preferably, the method does not reduce the molecular weight of carrageenan relative to the carrageenan without the sodium salt.

[0044] In one aspect, applying the solution to the crude carrageenan includes washing the crude carrageenan by the solution, or soaking the crude carrageenan in the solution, or mixing the solution to the crude carrageenan, or spraying the solution onto the crude carrageenan. In one aspect, in step (b), applying the solution to the crude carrageenan is conducted.

[0045] In one aspect, the acid is an organic acid. In one aspect, the acid is natural organic acid or chemically synthesized acid. In one aspect, the acid comprises citric acid, malic acid, tartaric acid, acetic acid or any combination thereof.

[0046] In one aspect, the second salt in the solution is a sodium salt. In one aspect, the second salt is organic acid salt. In one aspect, the second salt in the solution is a sodium salt of organic acid. In one aspect, the second salt comprises sodium citric, trisodium phosphate, tartrate sodium, or any combination thereof.

[0047] In one aspect, the alcohol comprises C2-C16 alkanol, C3-C16 unsaturated alcohol, C3-C20 alicyclic alcohol, C6-C20 aromatic alcohol, or any combination thereof. In one aspect, the alcohol comprises monohydric alcohols or polyhydric alcohols of C2-C16 alkanol, C3-C16 unsaturated alcohol, C3-C20 alicyclic alcohol, C6-C20 aromatic alcohol, or any combination thereof. In one aspect, C2-C 16 alkanol comprises C2 alkanol (e.g. ethanol), C3 alkanol (e.g. propanol or isopropanol), C4 alkanol (e.g. butanol, or isobutanol), C5 alkanol, C6 alkanol, C7 alkanol, C8 alkanol, C9 alkanol, CIO alkanol, Cl l alkanol, C12 alkanol, C13 alkanol, C14 alkanol, Cl 5 alkanol, C16 alkanol, or any combination thereof. In one aspect, the alcohol is ethanol. In one aspect, the alcohol is alcohol aqueous solution.

[0048] In one aspect, C3-C16 unsaturated alcohol comprises from C3 unsaturated alcohol to C16 unsaturated alcohol, or any combination thereof. C3-C20 alicyclic alcohol comprises from C3 alicyclic alcohol to C20 alicyclic alcohol, or any combination thereof. C6-C20 aromatic alcohol comprises from C6 aromatic alcohol to C20 aromatic alcohol, or any combination thereof.

[0049] In one aspect, the method further comprises: prior to the step (a), cooking seaweed at a temperature above 85°C to obtain a paste of dissolved seaweed, and fdtering the paste of dissolved seaweed to obtain the pulp of seaweed. In one aspect, cooking the seaweed is conducted at a temperature of about 90°C. In one aspect, the pulp of seaweed is syrupdike seaweed.

[0050] In one aspect, the crude carrageenan is further gelificated preferably by KC1 to obtain a wet cake. In one aspect, in step (a) the crude carrageenan is obtained in a form of wet cake, and in step (b) the wet cake is washed by the solution to obtain refined carrageenan, and preferably the refined carrageenan is dried to obtain the carrageenan. In one aspect, introduction of hydrogen ions and sodium ions to the carrageenan is conducted by washing the wet cake of crude carrageenan with the solution.

[0051] In one aspect, in step (a) the crude carrageenan is obtained in a form of wet cake, and in step (b) the wet cake is washed by the solution, and wherein the ratio by weight of the wet cake to the solution is 1 :0. 1 to 1:50. preferably from 1 : 1 to 1: 10, or more preferably from 1 :0.5 to 1 : 10.

[0052] In one aspect, the solution comprises 10-80%w / w alcohol solution, or preferably 10-50%w / w alcohol solution. In one aspect, the solution comprises 0.005M-0.2M or preferably 0.01M-0.1M of the acid. In one aspect, the solution comprises 0.005M-0.2M or preferably 0.01- 0.1M of the second salt.

[0053] In one aspect, the dried carrageenan is further crushed into carrageenan powder. In one aspect, the sodium ions are in an amount of l-10%w / w. or 2-9%w / w, or 2-8% w / w, or 2- 7%w / w or 2-6%w / w based on the carrageenan powder. In one aspect, an amount of Ca2+and K+is lower than 6%w / w, or lower than 5%w / w, or lower than 4%w / w, or lower than 3.8%w / w, or lower than 3%w / w, or lower than 2%w / w, based on the carrageenan powder. The amount of Ca2+and K+are in a range of 0. l-6%w / w, in a range of 0. l-5%w / w, or in a range of 0. l-4%w / w. or in a range of 0. l-3%w / w based on the carrageenan powder.

[0054] Without being bound by theory, the inventors of the present invention discovered that when hydrogen ions and sodium ions are introduced, the hydrogen ions and sodium ions can combine with sulfuric acid groups of carrageenan without destroying the molecular structure and molecular weight of carrageenan. The inventor discovered that the combination of hydrogen ions, sodium ions and sulfuric acid groups can make it hard to form -o— K+-o or o-Ca2+-o bridge structure, and thereby colloid of carrageenan would not easily form into gel I and gel I would not easily form into gel II, so as to maintain its reversibility and at the same time, carrageenan superstrands are not easily formed, reducing the gelling temperature and viscosity of carrageenan- based gel mass. Therefore, the carrageenan-based gel does not involve reducing the molecular weight of the carrageenan but meanwhile the gelling temperature and viscosity’ can be reduced, which makes the gel suitable for the application in the film of capsules, especially soft capsules.

[0055] The inventors discovered that when K+or Ca2+is introduced in the carrageenan solution, it will generate the binding point by potassium or calcium bridge, that will help to form helix (gel 1) and finally strong gel 2; however, when hydrogen or sodium ions are introduced in the carrageenan solution, the binding point will not be generated and it will prevent the formation of gel II. The inventors also discovered that when the pH is higher than 10, there is mainly carrageenan-sulfuric sodium form; when pH is in a range of 5-9, there is carrageenan-sulfuric sodium and carrageenan-sulfuric hydrogen form. This would lead to weak gel, and good filming capability; when the pH is lower than the range, such as lower than 4.6, there is mainly carrageenan-sulfuric hydrogen form, but autohydrolysis would start and carrageenan would be decreased.

[0056] In one aspect, the method comprises the use of the dried carrageenan, preferably the carrageenan powder, to generate a carrageenan-based gel. The method comprises combiningthe carrageenan, preferably the carrageenan powder, with starch, a first salt, glycerin and water. In one aspect, the carrageenan-based gel comprises 6-10wt% of carrageenan, 25-35wt% of starch (preferably modified starch), 0.5-1.5wt% of the first salt, and 15-25 wt% of glycerin and water in an amount which makes all components add up to 100wt%. In one aspect, the carrageenan-based gel is obtained by mixing the carrageenan, starch, the first salt, glycerine and water.EXAMPLES

[0057] The following examples are presented to further illustrate and explain the present invention and should not be taken as limiting in any regard.Example 1

[0058] Materials and methods of preparing carrageenan and carrageenan-based gel.

[0059] As shown in Figure 2, red seaweeds are cooked in hot water at a temperature of 90°C to dissolve the seaweeds to obtain a paste. The paste is filtered to obtain a pulp (with carrageenan concentration of 20g / l).KCl is mixed with the pulp of seaweeds for gelification to obtain crude carrageenan. The crude carrageenan is further gelificated by KC1 to obtain a wet cake. The wet cake is washed by the solution (i.e. buffer salt alcohol solution) to obtain refined carrageenan. The refined carrageenan is dried to obtain the carrageenan.

[0060] The compositions of the solution and the ratio of the wet cake to the solution are listed in table 1. The pH of carrageenan in table 1 is measured by dissolving lwt% of carrageenan into water to form a carrageenan solution and measuring the pH of the carrageenan solution.

[0061] The carrageenan-based gel mass includes 7.5wt% of carrageenan, 23.5wt% of hydroxypropyl starch, lwt% of sodium phosphate, 20wt% of glycerin and 48wt% water.

[0062] The results including setting temperature (i.e. gelling temperature) in gel mass, and viscosity of gel mass are also listed in Table 1.

[0063] All ingredients in the carrageenan are dissolved and stirred at high speed under pressure to reach a temperature of 90°C. The setting temperature and viscosity' were measured by using an equipment called HAAKE viscotester IQ. The setting temperature and viscosity were measured by an Oscillation temperature ramp in which the temperature was set from 100 degree and decreased to 50 degree with a frequency 1Hz and shear stress IPa. The viscosity at 90oC is read and the temperature at the point storage modulus = loss modulus is read as the gelling temperature.

[0064] The molecular weight and the source of samples are listed in table 2.Table 1Table 2

[0065] As shown in Table 2, samples 1-3 and control group 1 are derived from red seaweed 1, and samples 4-5 and control group 2 are derived from red seaweed 2. Red seaweed 1is E. Cottonii that is used to produce k-carrageenan and red seaweed 2 is E. Spinosum that is used to produce i-carrageenan.

[0066] As shown in Table 1, in sample 1, the solution comprises 50% ethanol, 0.04M sodium citric, and 0.06M citric acid. In sample 1, the ratio of the wet cake to the solution is 1:4 (w / w). The wet cake is washed by the solution and dried to obtain the final carrageenan with a pH of 7.8. Sodium ions are in an amount of 3. l%(w / w), and the ions of Ca2 i and K+ are in an amount of 0.5%(w / w). The setting temperature in gel mass and viscosity of gel mass at 90°C of sample 1 are 40.5°C and 210,000 cps, respectively. As shown in Table 2, the average molecular weight of sample 1 is 621,000 g / mol. The molecular weight of sample 1 less than 50,000 g / mol is 0.73%. The molecular weight of sample 1 less than 100, 000 g / mol is 2.95%.

[0067] As shown in Table 1, in control 1, based on the common process, red seaweeds went through the following procedures: alkali treatment (6% KOH, 67°C, 4h), extraction with hot water (95°C, 2h), filtration, gelling by cooling process with KC1, first pressing, washing the cake by KC1 solution, second pressing, drying the cake, grinding / sieving, and packaging in bags. In control 1, the ratio of the wet cake to the 30g / l KC1 solution is 1 : 1 (w / w). The wet cake is washed by the 30g / l KC1 solution and dried to obtain the final carrageenan with a pH of 9.6. Sodium ions are in an amount of 0.2%w / w, and the ions of Ca2+ and K+ are in an amount of 6.3%w / w. The setting temperature in gel mass and viscosity at 90°C of sample 1 are 84.0°C and 1,830,000 cps, respectively. As shown in Table 2, the average molecular weight of control 1 is 618,000 g / mol. The molecular weight of sample 1 less than 50,000 g / mol is 0.74%. The molecular weight of sample 1 less than 100, 000 g / mol is 3.23%.

[0068] It can be seen from the comparison between samples and control groups that the pH of carrageenan in the samples is lower than that of control groups and the amount of sodium ions in carrageenan in the samples is higher than that of control groups, which shows that a higher level of hydrogen ions and sodium ions are added in the samples compared with the control groups. The amounts of Ca2+ and K+ of samples are lower than those of control groups. The results indicate that the addition of hydrogen ions and sodium ions lead to a lower setting temperature and a lower viscosity without reducing the molecular weight of carrageenan, compared to control groups, which demonstrates that the method of the present invention and the resulting carrageenan-based gel are more suitable for the capsule films.

[0069] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of the invention belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning thatis consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0070] While the disclosure has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims.

[0071] Representative features of the present invention are set out in the following clauses, which stand alone or may be combined, in any combination, with one or more features disclosed in the text of the Specification.

[0072] The present invention is as set out in the following clauses:

[0073] Clause 1: A carrageenan, comprising sodium ions, wherein the sodium ions are in an amount of l-10%w / w, or 2-6%w / w based on the carrageenan, wherein when l%w / w of carrageenan is dissolved in water to form a carrageenan solution, pH of the carrageenan solution is in a range of 5-9, 7-9, or 7.8-9, wherein hydrogen ions, and the sodium ions are combined with sulfuric acid groups of the carrageenan to form carrageenan-sulfuric hydrogen and carrageenan-sulfuric sodium, respectively.

[0074] Clause 2: A carrageenan-based gel, comprising a carrageenan, a starch preferably a modified starch, a first salt, glycerin and water, wherein the carrageenan comprises sodium ions, and the sodium ions are in an amount of l-10%w / w, or 2-6%w / w based on the carrageenan, wherein when l%w / w of carrageenan is dissolved in water to form a carrageenan solution, pH of the carrageenan solution is in a range of 5-9, 7-9, or 7.8-9, wherein hydrogen ions, and the sodium ions are combined with sulfuric acid groups of the carrageenan to form carrageenan-sulfuric hydrogen and carrageenan-sulfuric sodium, respectively.

[0075] Clause 3: The carrageenan or the carrageenan-based gel of any one of preceding clauses, wherein an amount of Ca2+and K+in the carrageenan is lower than 6%w / w, or lower than 3.8%w / w, or in a range of 0. l-4%w / w, based on the carrageenan.

[0076] Clause 4: The carrageenan or the carrageenan-based gel of any one of preceding clauses, wherein the average molecular weight of carrageenan is greater than 500,000 g / mol.

[0077] Clause 5: The carrageenan or the carrageenan-based gel of any one of preceding clauses, wherein the viscosity of carrageenan-based gel mass at 90°C is lower than l,800,000cPs, or lower than 1,300, OOOcPs, or in a range of 100, 000-1, 800, OOOcPs, or in a range of 200, 000-1, 300, OOOcPs.

[0078] Clause 6: The carrageenan or the carrageenan-based gel of any one of preceding clauses, wherein the gelling temperature of the carrageenan-based gel mass is in a range of 40- 75°C, or 40-60°C.

[0079] Clause 7: Use of the carrageenan or the carrageenan-based gel of any one of preceding clauses in a capsule film.

[0080] Clause 8: A method of producing carrageenan, comprising:(a) gelificating a pulp of seaweed preferably by KC1 to obtain a crude carrageenan;(b) applying a solution to the crude carrageenan to obtain the carrageenan wherein the solution comprises an acid, preferably an organic acid, a second salt other than potassium salts and calcium salts, and alcohol, and the method does not reduce the molecular weight of carrageenan.

[0081] Clause 9: The method of clause 8, wherein the acid is natural organic acid.

[0082] Clause 10: The method of clause 8 or 9, wherein the acid comprises citric acid, malic acid, tartaric acid, acetic acid or any combination thereof.

[0083] Clause 1 1: The method of any one of clauses 8-10, wherein the second salt is a sodium salt.

[0084] Clause 12: The method of any one of clauses 8-11, wherein the second salt is organic acid salt, preferably the second salt comprises sodium citric, trisodium phosphate, tartrate sodium, or any combination thereof.

[0085] Clause 13: The method of any one of clauses 8-12, wherein the alcohol comprises C2-C16 alkanol, C3-C16 unsaturated alcohol, C3-C20 alicyclic alcohol, C6-C20 aromatic alcohol, or any combination thereof.

[0086] Clause 14: The method of any one of clauses 8-13, wherein the method further comprises: prior to the step (a), cooking seaweed at a temperature above 85°C to obtain a paste of dissolved seaweed, and fdtering the paste of dissolved seaweed to obtain the pulp of seaweed.

[0087] Clause 15: The method of any one of clauses 8-14, wherein in step (a) the crude carrageenan is obtained in a form of wet cake, and in step (b) the wet cake is washed by the solution to obtain refined carrageenan, and preferably the refined carrageenan is dried to obtain carrageenan.

[0088] Clause 16: The method of any one of clauses 8-15, wherein in step (a) the crude carrageenan is obtained in a form of wet cake, and in step (b) the wet cake is washed by the solution, and wherein the ratio by weight of the wet cake to the solution is 1:0.1 to 1:50, or from 1 :0.5 to 1: 10.

[0089] Clause 17: The method of any one of clauses 8-16, wherein the solution comprises 10-80% or 10-50% alcohol solution, and 0.005M-0.2M or 0.01M-0.1M of the acid, and 0.005M-0.2M or 0.01-0. IM of the salt.

[0090] Clause 18: A carrageenan-based gel comprising the carrageenan of any one of claims 1, 3-6, and further comprising a starch preferably a modified starch, a first salt, glycerin and water.

Claims

CLAIMS1. A carrageenan, comprising sodium ions, wherein the sodium ions are in an amount of l-10%w / w, or 2-6%w / w based on the carrageenan, wherein when l%w / w of carrageenan is dissolved in water to form a carrageenan solution, pH of the carrageenan solution is in a range of 5-9, 7-9, or 7.8-9, wherein hydrogen ions, and the sodium ions are combined with sulfuric acid groups of the carrageenan to form carrageenan-sulfuric hydrogen and carrageenan-sulfuric sodium, respectively.

2. A carrageenan-based gel, comprising a carrageenan, a starch preferably a modified starch, a first salt, glycerin and water, wherein the carrageenan comprises sodium ions, and the sodium ions are in an amount of l-10%w / w, or 2-6%w / w based on the carrageenan, wherein when l%w / w of carrageenan is dissolved in water to form a carrageenan solution, pH of the carrageenan solution is in a range of 5-9, 7-9, or 7.8-9, wherein hydrogen ions, and the sodium ions are combined with sulfuric acid groups of the carrageenan to form carrageenan-sulfuric hydrogen and carrageenan-sulfuric sodium, respectively.

3. The carrageenan or the carrageenan-based gel of any preceding claims, wherein an amount of Ca2+and K+in the carrageenan is lower than 6%w / w, or lower than 3.8%w / w, or in a range of 0. l-4%w / w, based on the carrageenan.

4. The carrageenan or the carrageenan-based gel of any one of preceding claims, wherein the average molecular weight of carrageenan is greater than 500,000 g / mol.

5. The carrageenan or the carrageenan-based gel of any one of preceding claims, wherein the viscosity of carrageenan-based gel mass at 90°C is lower than l,800,000cPs, or lower than l,300,000cPs, or in a range of 100, 000-1, 800, OOOcPs, or in a range of 200, 000-1, 300, OOOcPs.

6. The carrageenan or the carrageenan-based gel of any one of preceding claims, wherein the gelling temperature of the carrageenan-based gel mass is in a range of 40-75°C, or 40-60°C.

7. Use of the carrageenan or the carrageenan-based gel of any one of preceding claims in a capsule film.

8. A method of producing carrageenan, comprising:(a) gelificating a pulp of seaweed preferably by KC1 to obtain a crude carrageenan; and(b) applying a solution to the crude carrageenan to obtain the carrageenan, wherein the solution comprises an acid, preferably an organic acid, a second salt other than potassium salts and calcium salts, and alcohol, and the method does not reduce the molecular weight of carrageenan.

9. The method of claim 8, wherein the acid is natural organic acid.

10. The method of claim 8 or 9, wherein the acid comprises citric acid, malic acid, tartaric acid, acetic acid or any combination thereof.

11. The method of any one of claims 8-10, wherein the second salt is a sodium salt.

12. The method of any one of claims 8-11, wherein the second salt is organic acid salt, or the second salt comprises sodium citric, trisodium phosphate, tartrate sodium, or any combination thereof.

13. The method of any one of claims 8-12, wherein the alcohol comprises C2-C16 alkanol, C3-C16 unsaturated alcohol, C3-C20 alicyclic alcohol, C6-C20 aromatic alcohol, or any combination thereof.

14. The method of any one of claims 8-13. wherein the method further comprises: prior to the step (a), cooking seaweed at a temperature above 85°C to obtain a paste of dissolved seaweed, and filtering the paste of dissolved seaweed to obtain the pulp of seaweed.

15. The method of any one of claims 8-14, wherein in step (a) the crude carrageenan is obtained in a form of wet cake, and in step (b) the wet cake is washed by the solution to obtain refined carrageenan, and preferably the refined carrageenan is dried to obtain the carrageenan.

16. The method of any one of claims 8-15, wherein in step (a) the crude carrageenan is obtained in a form of wet cake, and in step (b) the wet cake is washed by the solution, and wherein the ratio by weight of the wet cake to the solution is 1 :0.1 to 1:50, or from 1:0.5 to 1 :10.

17. The method of any one of claims 8-16, wherein the solution comprises 10-80% or 10-50% alcohol solution, and 0.005M-0.2M or 0.01M-0.1M of the acid, and 0.005M-0.2M or 0.01- 0. IM of the salt.

18. A carrageenan-based gel comprising the carrageenan of any one of claims 1. 3-6, and further comprising a starch preferably a modified starch, a first salt, glycerin and water.

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