INULIN COMPOSITION AND METHOD OF PURIFYING INULIN

Title:

INULIN COMPOSITION AND METHOD OF PURIFYING INULIN

Document Type and Number:

WIPO Patent Application WO/2020/182714

Kind Code:

Abstract:

The present invention relates to a method for purifying an aqueous liquid comprising inulin, in particular chicory root inulin, and one or more impurities, said method comprising filtration of said aqueous liquid employing a nano filtration membrane having a molecular weight cut-off value of less than 2 kDa, without employing ion-exchange treatment. The invention further relates to the inulin composition obtainable by the method and to inulin compositions which comprise low concentrations of impurities while comprising significant amounts of short-chain (low DP) inulin.

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Inventors:

DE ROODE BARTHOLOMEUS MATTHEUS (NL)
DE WIT MARGARETHA JOHANNA (NL)
VAN DEN BERGH JOHAN (NL)
MICHIELSEN MAX CORNELIS ADRIANUS MARIA (NL)

Application Number:

PCT/EP2020/056179

Publication Date:

September 17, 2020

Filing Date:

March 09, 2020

Export Citation:

Click for automatic bibliography generation Help

Assignee:

SENSUS B V (NL)

International Classes:

C08B37/00

Foreign References:

EP0787745A2	1997-08-06
CN102504048A	2012-06-20
CN108424478A	2018-08-21
CN106947006A	2017-07-14
US20150329927A1	2015-11-19
US5968365A	1999-10-19
US5254174A	1993-10-19
CN102504048A	2012-06-20
CN106947006A	2017-07-14
CN108424478A	2018-08-21
EP0787745A2	1997-08-06

Other References:

HANG HUA ET AL: "Enzyme membrane reactor coupled with nanofiltration membrane process for difructose anhydride III from inulin conversion", CHEMICAL ENGINEERING JOURNAL, ELSEVIER, AMSTERDAM, NL, vol. 276, 8 April 2015 (2015-04-08), pages 75 - 82, XP029606965, ISSN: 1385-8947, DOI: 10.1016/J.CEJ.2015.04.018
PATIL NIRMAL V ET AL: "Separation of an inulin mixture using cascaded nanofiltration", SEPARATION AND PURIFICATION TECHNOLOGY, vol. 146, 4 April 2015 (2015-04-04), pages 261 - 267, XP029156979, ISSN: 1383-5866, DOI: 10.1016/J.SEPPUR.2015.03.061
MORENO-VILET L ET AL: "Assessment of sugars separation from a model carbohydrates solution by nanofiltration using a design of experiments (DoE) methodology", SEPARATION AND PURIFICATION TECHNOLOGY, vol. 131, 5 May 2014 (2014-05-05), pages 84 - 93, XP028851071, ISSN: 1383-5866, DOI: 10.1016/J.SEPPUR.2014.04.040
NARINDER KAUR ET AL: "714 | Indian Academy of Sciences Applications of inulin and oligofructose in health and nutrition", JOURNAL OF BIOSCIENCES., vol. 27, no. 7, 1 December 2002 (2002-12-01), IN, pages 703 - 714, XP055230857, ISSN: 0250-5991, DOI: 10.1007/BF02708379
E. BERGHOFER ET AL.: "Studies in Plant Science", vol. 3, 1993, ELSEVIER, article "Pilot-scale production of inulin from chicory roots and its use in foodstuffs", pages: 77 - 84
TIMMERMANS, J. W.VAN LEEUWEN, M. B.TOURNOIS, H.DE WIT, D.VLIEGENTHART, J. F. G.: "Quantitative Analysis of the Molecular Weight Distribution of Inulin by Means of Anion Exchange HPLC with Pulsed Amperometric Detection", JOURNAL OF CARBOHYDRATE CHEMISTRY, vol. 13, no. 6, 1994, pages 881 - 888

Attorney, Agent or Firm:

NEDERLANDSCH OCTROOIBUREAU (NL)

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Claims:

CLAIMS

1 . A method for purifying an aqueous liquid comprising inulin, said method comprising the steps of:

a) providing an aqueous liquid comprising:

• inulin, wherein more than 5 wt.% (by weight of inulin), preferably more than 8 wt.%, more preferably more than 12 wt.% of the inulin has a DP within the range of 3-5, said inulin comprising GpyFn inulins with a terminal glucose, wherein the GpyFn inulins have a chain length distribution wherein every DP within the range of 3-60 is present in an amount of at least 0.1 %, preferably at least 1 %;

• lactucins in an amount of more than 0.1 wt.% (by weight of inulin), preferably more than 0.3 wt.%;

• sugars in an amount of more than 3 wt.% (by weight of inulin), preferably more than 4 wt.%, more preferably more than 5 wt.%;

• more than 3 wt.% (by weight of inulin), preferably more than 4 wt.% of minerals; and

• more than 3 wt.% (by weight of inulin), preferably more than 4 wt.% of organic acids, wherein the organic acids are preferably chosen from the group consisting of citric acid, malic acid, lactic acid, formic acid, acetic acid, propionic acid, butyric acid and combinations thereof;

b) subjecting the aqueous liquid of step a) to a nanofiltration step employing a nanofiltration membrane having a molecular weight cut-off value of less than 2 kDa, preferably less than 1 .5 kDa, more preferably less than 1 .2 kDa, more preferably less than 1 .05 kDa; and

c) collecting the retentate of nanofiltration step b) comprising:

• inulin, wherein more than 2% (by weight of inulin), preferably more than 4%, more preferably more than 6% of the inulin has a DP within the range of 3-5, said inulin comprising GpyFn inulins with a terminal glucose, wherein the GpyFn inulins have a chain length distribution wherein every DP within the range of 3- 60 is present in an amount of at least 0.1 %, preferably at least 1 %;

• less than 0.1 wt.% (by weight of inulin), preferably less than 0.05 wt.%, more preferably less than 0.01 wt.% of lactucins;

• less than 3 wt.% (by weight of inulin), preferably less than 2 wt.%, more preferably less than 1 .5 wt.% of sugars;

• less than 20 wt.% (by weight of inulin), preferably less than 10 wt.%, more preferably less than 5 wt.%, even more preferably less than 2 wt.% of FpyFn;

• more than 0.1 wt.% (by weight of inulin), preferably more than 0.8 wt.% of minerals; and

• more than 0.1 wt.% (by weight of inulin), preferably more than 0.8 wt.% of organic acids wherein the organic acids are preferably chosen from the group consisting of citric acid, malic acid, lactic acid, formic acid, acetic acid, propionic acid, butyric acid and combinations thereof,

wherein the method does not comprise an ion-exchange treatment. 2. The method according to claim 1 wherein step a) comprises the following steps:

a1) providing a plant material comprising inulin, proteins, sugars and lactucins, preferably chicory root;

a2) subjecting the plant material to a processing step to provide an aqueous liquid comprising inulin, sugars, proteins and lactucins and processed plant material;

a3) separating the processed plant material and the aqueous liquid; and

a4) subjecting the aqueous liquid to a protein removal step wherein the proteins are at least partially removed to provide the aqueous liquid of step a).

3. The method according to claim 1 or 2 wherein step a) comprises the following steps:

a1) providing a plant material comprising inulin, proteins, sugars and lactucins, preferably chicory root;

a2) contacting the plant material with an aqueous extraction liquid for an amount of time sufficient to provide an aqueous extraction liquid comprising inulin, sugars, proteins and lactucins and processed plant material;

a3) separating the processed plant material and the aqueous extraction liquid; and a4) submitting the aqueous extraction liquid to a protein removal step wherein the proteins are at least partially removed to provide the aqueous liquid of step a).

4. The method according to any one of claims 1 to 3, wherein the aqueous liquid provided in step a) comprises more than 1 wt.% (by weight of aqueous liquid), preferably more than 5 wt.%, more preferably more than 10 wt.% of inulin.

5. The method according to any one of the preceding claims wherein the aqueous liquid provided in step a) comprises one or two of the following:

· more than 0.4 wt.% (by weight of inulin), preferably more than 0.6 wt.%, more preferably more than 0.8 wt.% of sesquiterpene lactones;

• more than 0.05 wt.% (by weight of inulin), preferably more than 0.1 wt.% of polyphenols. 6. The method according to any one of the preceding claims wherein the aqueous liquid provided in step a) has not been subjected to active carbon filtration prior to step b).

7. The method according to any one of the preceding claims wherein the nanofiltration membrane employed in step b) has a molecular weight cut-off value of more than 0.5 kDa, more than 0.6 kDa, more than 0.7 kDa, more than 0.8 kDa, or more than 0.9 kDa. 8. The method according to any one of the preceding claims wherein the nanofiltration membrane employed in step b) comprises or consists of one or more polymers selected from the group consisting of polyamide (PA), polysulfone (PS), polyethersulfone (PES), polyimide, and polypiperazine, preferably polyamide (PA) or polypiperazine.

9. The method according to any one of the preceding claims further comprising the step d) of concentrating the retentate obtained in step c) to provide an inulin concentrate with an inulin concentration of at least 20 wt.%, preferably at least 60 wt.%.

10. The method according to claim 9 wherein step d) comprises or consists of evaporation and/or spray-drying.

1 1 . The method according to any one of the preceding claims wherein the method does not comprise active carbon filtration.

12. The method according to any one of the previous claims further comprising subjecting the retentate collected in step c) and/or the concentrate of step d) to chemical or enzymatic hydrolysis treatment, preferably enzymatic hydrolysis treatment, resulting in an increase in FpyFn content, such that a hydrolyzed inulin composition comprising more than 20 wt.% (by weight of inulin), preferably more than 40 wt.%, more preferably more than 60 wt.% of FpyFn is obtained.

13. Inulin composition obtainable by the method according to any one of claims 1 -1 1 or hydrolyzed inulin composition obtainable by the method according to claim 12.

14. Inulin composition which comprises:

• inulin, wherein more than 2%, preferably more than 4%, more preferably more than 6% of the inulin has a DP within the range of 3-5, said inulin comprising GpyFn inulins with a terminal glucose, wherein the GpyFn has a chain length distribution wherein every DP within the range of 3-60 is present in an amount of at least 0.1 %, preferably at least 1 %;

• less than 0.1 wt.% (by weight of inulin), preferably less than 0.05 wt.%, more preferably less than 0.01 wt.% of lactucins;

• less than 3 wt.% (by weight of inulin), preferably less than 2 wt.%, more preferably less than 1 .5 wt.% of sugars;

• less than 20 wt.% (by weight of inulin), preferably less than 10 wt.%, more preferably less than 5 wt.%, even more preferably less than 2 wt.% of FpyFn;

• more than 0.1 wt.% (by weight of inulin), preferably more than 0.8 wt.% of minerals; and • more than 0.1 wt.% (by weight of inulin), preferably more than 0.8 wt.% of organic acids, wherein the organic acids are preferably chosen from the group consisting of citric acid, malic acid, lactic acid, formic acid, acetic acid, propionic acid, butyric acid and combinations thereof.

15. Inulin composition in accordance with claim 14 in the form of a spray-dried powder comprising more than 80 wt.%, preferably more than 85 wt.%, more preferably more than 90 wt.%, most preferably more than 95 wt.%, of inulin and which has a dry matter content of more than 80% (w/v), preferably more than 85% (w/v), more preferably more than 90% (w/v), most preferably more than 95% (w/v).

16. Inulin composition in accordance with any one of claims 13-15, which comprises more than 1 wt.% (by total weight of the inulin composition), preferably more than 5 wt.%, more preferably more than 10 wt.% of inulin.

17. Inulin composition in accordance with any one of claims 13-16, which comprises one or more, such as two, three or all of the following:

• less than 0.4 wt.% (by weight of inulin), preferably less than 0.2 wt.%, more preferably less than 0.1 wt.% of sesquiterpene lactones;

• less than 3 wt.% (by weight of inulin), preferably less than 1 .5 wt.% of minerals;

• less than 2.5 wt.% (by weight of inulin), preferably less than 1 .5 wt.% of organic acids, wherein the organic acids are preferably chosen from the group consisting of citric acid, malic acid, lactic acid, formic acid, acetic acid, propionic acid, butyric acid and combinations thereof;

• less than 0.05 wt.% (by weight of inulin), preferably less than 0.03 wt.% of polyphenols;

• more than 0.005 wt.% (by weight of inulin), preferably more than 0.01 wt.% of polyphenols.

18. Alimentary product comprising the inulin composition in accordance with any one of claims 13-17 or comprising the hydrolyzed inulin composition in accordance with claim 13.

19. Use of the inulin composition in accordance with any one of claims 13-17 or the hydrolyzed inulin composition in accordance with claim 13:

• as a prebiotic agent;

• to increase the carbohydrate fiber content of an alimentary product;

• as a gelling agent;

• as a carbohydrate fiber in an alimentary product;

• as a fat replacer;

• as a sugar replacer; • to improve taste;

• as a texture enhancer;

• to improve the mouthfeel of an alimentary product;

• to improve the spreadability of an alimentary product; · as an emulsion stabilizer;

• to improve the moisture retention of an alimentary product;

• to improve the crispness of an alimentary product; and/or

• to improve the heat resistance of an alimentary product.

Description:

INULIN COMPOSITION AND METHOD OF PURIFYING INULIN

FIELD OF THE INVENTION

[0001] The present invention relates to a method for purifying an aqueous liquid comprising inulin, in particular comprising chicory root inulin, and several impurities. The invention further relates to the inulin composition obtainable by the method and to inulin compositions which comprise low concentrations of said impurities while still comprising significant amounts of short-chain (low DP) inulin, long-chain (high DP) inulin, minerals and organic acids. The invention also concerns alimentary products comprising said inulin compositions and specific uses of said inulin compositions.

BACKGROUND OF THE INVENTION

[0002] Inulins are a group of naturally occurring polysaccharides which have many known uses, for example as a prebiotic, as a low-caloric dietary fiber or as a gelling agent in foodstuff. Inulins are linear chains consisting of fructose units connected via a b (2-1) bond, which typically have a terminal glucose unit. The number of monosaccharide units is commonly referred to as the degree of polymerization (DP) and typically ranges from 3 to 80. Chicory inulin typically comprises 20-35% DP3-DP9 inulin and 65-80% DP10 and higher inulin.

[0003] Inulins are most commonly extracted from plant material, such as chicory root which typically contains 70-80% (dry weight) of inulins. Inulin compositions which have a chain length distribution which resembles that of the inulin as present in the plant material, most notably characterized by the presence of both short chain inulins (e.g. with a DP of 2-10 or 2-6) and long chain inulins (e.g. with a DP of 1 1 -60 or 7-60), are sometimes referred to as‘native inulin'. Native inulin compositions have been associated with beneficial effects, such as prebiotic effects.

[0004] Industrial scale inulin production typically involves hot water extraction of sliced plant material, followed by purification of the crude extract and isolation of the inulin. The production of inulin from chicory root poses specific challenges because of the presence of large amounts of sesquiterpene lactones, which are not significantly present in other inulin sources such as e.g. Jerusalem Artichoke. Sesquiterpene lactones, and more specifically the lactucin-type sesquiterpene lactones, have an undesirable, bitter taste.

[0005] Purification of the crude extract is almost exclusively done by ion-exchange treatment combined with active carbon filtration. The use of ion-exchange resins and the consequential need for their regeneration has a considerable negative environmental impact. Regenerating ion- exchange resins consumes large amounts of energy and reagents such as strong acids or bases, which results into a large carbon footprint for commercially available inulin products. Additionally, the ion-exchange treatment results in the (or too much) removal of nutritionally valuable compounds naturally present in the plant material, such as minerals and organic acids, while sugars remain present in the final inulin composition. The presence of sugars is undesirable in view of the current consumer demand for low sugar products. [0006] Isolation of inulin from the extract by crystallization may in some circumstances lead to a sesquiterpene-lactone-free and sugar-free product without requiring ion-exchange treatment, but this has the disadvantage that short chain inulin is lost as these mostly remain in solution. Hence, the crystallized end product does not reflect the‘native’ inulin, as it typically contains even less than 0.5 wt.% of DP3-5 inulin (by weight of inulin).

[0007] Berghofer et al. (E. Berghofer et at , "Pilot-scale production of inulin from chicory roots and its use in foodstuffs." Studies in Plant Science. Vol. 3. Elsevier, 1993. 77-84) describe the isolation of inulin from raw juice obtained after extraction of sliced chicory roots by ultrafiltration over a 5 kDa membrane and subsequent spray-drying of the retentate. Berghofer et al. note that the greater part of the ash (minerals) passed into the permeate and describes samples containing major impurities as having a bitter taste. Berghofer et al. also describe that ultrafiltration enriches higher molecular weight inulin, stating that the average DP was found to be as high as 40-45 (compared to 20-25 for samples obtained from the same plant material through crystallization).

[0008] US5968365 discloses a process for separating a first aqueous inulin solution containing carbohydrates having a range of degrees of polymerization into fractions having different average degrees of polymerization, which process comprises subjecting an aqueous inulin solution to ultrafiltration through a membrane having a predetermined pore size whereby inulin fractions having average degrees of polymerization less than a predetermined value pass through said membrane permeate and inulin fractions having average degrees of polymerization greater than said predetermined value are collected as retentate.

[0009] US5254174 discloses physical separation processes to reduce the amount of fructose, glucose and sucrose in a juice or syrup comprising fructose, glucose, sucrose and oligosaccharides. The lowest amount of sucrose+glucose+fructose achieved from a juice or syrup obtained from Jerusalem artichoke is described in example 4, wherein nanofiltration and ion-exchange chromatography treatments are applied and is 3% by weight of dry matter (3,33% by weight of inulin). Example 2 describes the use of nanofiltration alone, resulting in a sucrose+glucose+fructose content of 12% by weight of dry matter (13,33% by weight of inulin) from a juice or syrup obtained from Jerusalem artichoke.

[0010] CN102504048, CN106947006 and CN108424478 disclose processes wherein aqueous inulin extracts are purified using a process comprising ion-exchange treatment.

[0011] EP0787745A2 discloses processes wherein aqueous inulin extracts are purified. In Option

I of the processes, inulin with DP>40 is removed and ion-exchange treatment is applied. In Option

II of the processes, ion-exchange treatment is applied.

[0012] There is thus a need to provide an economically feasible method for purifying an aqueous liquid comprising inulin and one or more impurities, which is capable of reducing or removing impurities such as lactucins and sugars while preserving low DP inulin, high DP inulin, and preferably also nutritionally valuable compounds naturally present in the plant material, such as minerals and organic acids, and which may be characterized by a reduced environmental impact. There is also a need to provide more nutritionally optimized inulin compositions, such as inulin compositions comprising low DP inulin and high DP inulin (like in native inulin), while comprising low amounts of sugars and preferably substantial amounts of minerals and organic acids compared to currently available inulin compositions. It is an object of the invention to provide such improved methods and improved products.

SUMMARY OF THE INVENTION

[0013] The present inventors have surprisingly found that one or more of these objects are achieved by a method for purifying an aqueous liquid comprising inulin, lactucins and sugars, and preferably minerals and organic acids, wherein said inulin comprises a significant amount of low DP inulin and wherein said method comprises filtration of said aqueous liquid by employing a nanofiltration membrane having a molecular weight cut-off value of less than 2 kDa, and without employing ion-exchange treatment.

[0014] As will be shown in the appended examples, it was surprisingly found that the selection of an appropriate nanofiltration membrane allows the removal of lactucins and sugars from an aqueous liquid comprising inulin having a significant amount of low DP inulin, lactucins and sugars, while at the same time the nanofiltration preserves low DP inulin. It was further surprisingly found that the selection of this nanofiltration membrane leaves substantial amounts of minerals and organic acids in the retentate that would have been removed from the product with a technique such as ion-exchange treatment. Such an advantageous separation of low DP inulin, minerals and organic acids on the one hand and sugars and lactucins on the other hand could not have been expected based on the molecular sizes of the respective compounds. The method of the present invention may be qualified as environmentally friendly and allows high yields of inulin to be achieved and thus provides a viable industrial-scale method for the purification of aqueous liquids comprising inulin having a significant amount of low DP inulin, lactucins and sugars.

[0015] The resulting inulin composition still comprises low DP inulin and substantial amounts of minerals and organic acids, while comprising only low amounts of impurities such as sugar and lactucins. It is minimally processed, has a neutral taste, and qualifies as what is commonly referred to as‘native’ or‘raw’ inulin, i.e. it still comprises substantial amounts of all the different DP’s which are present in the chicory root.

[0016] These unique DP characteristics, combined with substantial amounts of minerals and organic acids and low amounts of lactucins, of the inulin composition in accordance with the invention are also reflected in the corresponding hydrolyzed inulin product, wherein part of the inulin has been enzymatically cleaved to provide an inulin composition comprising large amounts of inulins without a terminal glucose.

DEFINITIONS

[0017] As used herein, the term‘inulin’ refers to polymers composed of linear chains of fructose units connected via a b (2-1) glycosidic bond which may have a terminal glucose unit, wherein the number of monosaccharide units in an inulin molecule (commonly referred to as the degree of polymerization, DP) is at least 3. Inulins with a terminal glucose (a/p/?a-D-glucopyranosyl-[beta-D- fructofuranosyl](n-1)-D-fructofuranosides) are referred to herein as GpyFn inulins. Inulins without a terminal glucose (Jbefa-D-fructopyranosyl-[D-fructofuranosyl](n-1)-D-fructofu ranosides) are referred to herein as FpyFn. The wording‘inulin comprising GpyFn inulins’ as used herein refers to inulin having GpyFn inulin chains with different degree of polymerization. Likewise, the wording‘inulin comprising FpyFn inulins’ as used herein refers to inulin having FpyFn inulin chains with different degree of polymerization.

[0018] As is known to the skilled person, naturally occurring inulin mainly comprises GpyFn, but FpyFn may be present as a product of the hydrolysis of inulins, for example resulting from spontaneous degradation or resulting from a chemical or an enzymatic treatment wherein inulins are hydrolyzed.

[0019] A suitable method to determine the inulin chain length distribution is by a chromatographic method, such as high performance anion exclusion chromatography coupled to pulsed amperometric detection (HPAEC-PAD). A preferred method to determine the inulin chain length distribution is in accordance with the HPAEC-PAD protocol described herein. Thus, in embodiments, the methods and products of the invention are provided, having the inulin chain length distribution characteristics as described herein when determined in accordance with the HPAEC-PAD protocol described herein.

[0020] As used herein, the term‘lactucins’ refers to or comprises lactucin, dihydro-lactucin, 8- deoxylactucin-15-oxalate, 8-deoxylactucin and dihydro-8-deoxylactucin. A suitable method to determine the lactucins content, defined as the combined amount (i.e. the sum of) lactucin, dihydro- lactucin, 8-deoxylactucin-15-oxalate, 8-deoxylactucin and dihydro-8-deoxylactucin, is by a chromatographic method, such as ultra-high pressure liquid chromatography coupled to mass spectrometry (UHPLC-MS). A preferred method to determine the lactucins content is in accordance with the UHPLC-MS protocol described herein. Thus, in embodiments, the methods and products of the invention are provided, having the lactucins content characteristics as described herein when determined in accordance with the UHPLC-MS protocol described herein.

[0021] As used herein, the term‘sesquiterpene lactones’ refers to or comprises lactucin, dihydro- lactucin, 8-deoxylactucin-15-oxalate, 8-deoxylactucin, dihydro-8-deoxylactucin, lactucopicrin-15- oxalate, dihydro-lactucopicrin-oxalate, dihydro-lactucopicrin and lactucopicrin. A suitable method to determine the sesquiterpene lactone content, defined as the combined amount (i.e. the sum) of lactucin, dihydro-lactucin, 8-deoxylactucin-15-oxalate, 8-deoxylactucin, dihydro-8-deoxylactucin, lactucopicrin-15-oxalate, dihydro-lactucopicrin-oxalate, dihydro-lactucopicrin and lactucopicrin is by a chromatographic method, such as ultra-high pressure liquid chromatography coupled to mass spectrometry (UHPLC-MS). A preferred method to determine the sesquiterpene lactone content is in accordance with the UHPLC-MS protocol described herein. Thus, in embodiments, the methods and products of the invention are provided, having the sesquiterpene lactone content characteristics as described herein when determined in accordance with the UHPLC-MS protocol described herein.

[0022] As used herein, the term ‘sugars’ refers to glucose monosaccharides, fructose monosaccharides, fructose-fructose disaccharides and glucose-fructose disaccharides. Thus, in view of the definitions provided herein, sucrose is included in the term‘sugars’ and excluded from the term‘inulin’. A suitable method to determine the sugar content, defined as the combined amount (i.e. the sum) of glucose monosaccharide, fructose monosaccharides, fructose-fructose disaccharides and glucose-fructose disaccharides is by a chromatographic method such as gel permeation chromatography coupled to a refractive index detector (GPC-RI). A preferred method to determine the sugar content is in accordance with the GPC-RI protocol described herein. Thus, in embodiments, the methods and products of the invention are provided, having the sugar content characteristics as described herein when determined in accordance with the GPC-RI protocol described herein.

[0023] As used herein, the term‘nanofiltration’ (sometimes referred to in the art as ultrafiltration) refers to filtration using membranes with a pore size of less than 10 nm.

[0024] As used herein, the term‘microfiltration’ refers to filtration using membranes with a pore size of 0.1-10 pm.

[0025] The term‘chicory’, as used herein, refers to plants of the genus Cichorium, including plants of the species Cichorium endivia, plants of the species Cichorium intybus, varieties thereof, and hybrids thereof. The term "chicory" includes plants of the species Cichorium intybus, including "wild improved" chicories, "Barbe de Capucin" chicories, "sugar loaf chicories, "Chioggia" chicories, "cicorino" chicories, "Verona" chicories, "Catalonia" chicories, "Treviso" chicories, "Variegato di Castelfranco" chicories, "Witloof chicories (e.g., "Brussels" chicory or "chicon" chicory), "Soncino" chicories, "red" chicories (e.g., radicchios), "Industrial" chicories (e.g., chicories intended for roasting and for sugars), "fodder" or "game" chicories, and hybrids thereof. The term "chicory" also includes plants of the species Cichorium endivia, including curly endive, also referred to as frisee (var. crispum), escarole, or broad-leaved endive (var. latifolia), and hybrids thereof.

[0026] As used herein, the term‘minerals’ refers to chloride, bromide, nitrate, malate, sulfate, oxalate, phosphate, potassium, sodium, calcium and magnesium. As will be appreciated by those skilled in the art, these are minerals naturally present in the source of the inulin that is present in the aqueous liquid to be purified in the methods as defined herein. Stated differently, these are minerals naturally present in the plant material that is extracted to provide the aqueous liquid to be purified in the methods as defined herein A suitable method to determine the mineral content, defined as the combined amount (i.e. the sum) of chloride, bromide, nitrate, malate, sulfate, oxalate, phosphate, potassium, sodium, calcium and magnesium, is by determining the anion content by chromatography, such as high pressure ion chromatography coupled to a conductivity detector (HPIC-CD) and by determining the cation content by inductively coupled plasma - atomic emission spectroscopy (IPC-AES) analysis. A preferred method to determine the mineral content is in accordance with the HPIC-CD protocol described herein (for the anions) and in accordance with the IPC-AES protocol described herein (for the cations). Thus, in embodiments, the methods and products of the invention are provided, having the mineral content characteristics as described herein when determined in accordance with the HPIC-CD protocol described herein (for the anions) and in accordance with the IPC-AES protocol described herein (for the cations).

[0027] As used herein the term‘organic acids’ refers to citric acid, malic acid, lactic acid, formic acid, acetic acid, propionic acid and butyric acid. As will be appreciated by those skilled in the art, these are organic acids naturally present in the source of the inulin that is present in the aqueous liquid to be purified in the methods as defined herein. Stated differently, these are organic acids naturally present in the plant material that is extracted to provide the aqueous liquid to be purified in the methods as defined herein. A suitable method to determine the organic acid content, defined as the combined amount (i.e. the sum) of citric acid, malic acid, lactic acid, formic acid, acetic acid, propionic acid and butyric acid, is by chromatography, such as high pressure liquid chromatography coupled to a conductivity detector (HPLC-CD). A preferred method to determine the organic acids content is in accordance with the HPLC-CD protocol described herein. Thus, in embodiments the methods and products of the invention are provided, having the organic acids content characteristics as described herein when determined in accordance with the HPLC-conductivity protocol described herein.

[0028] As used herein the term ‘polyphenols’ refers to 4-O-caffeoylquinate, chlorogenic acid, caffeic acid and cichoric acid. A suitable method to determine the polyphenols content, defined as the combined amount (i.e. the sum) of 4-O-caffeoylquinate, chlorogenic acid, caffeic acid and cichoric acid is by liquid chromatography coupled to UV and subsequent mass spectrometry detection (LC-MS). A preferred method to determine the polyphenols content is in accordance with the LC-MS protocol described herein. Thus, in embodiments, the methods and products of the invention are provided, having the polyphenols content characteristics as described herein when determined in accordance with the LC-MS protocol described herein.

[0029] As used herein, the term‘ion-exchange treatment' comprises cation exchange using an ion-exchange resin, anion exchange using an ion-exchange resin as well as ion-exchange chromatography.

DETAILED DESCRIPTION

[0030] According to an aspect of the present invention, there is provided a method for purifying an aqueous liquid comprising inulin, said method comprising the steps of:

a) providing an aqueous liquid comprising inulin and one or both of the following components:

• lactucins in an amount of more than 0.01 wt.% (by weight of inulin), preferably more than 0.1 wt.%, more preferably more than 0.3 wt.%; and

• sugars in an amount of more than 3 wt.% (by weight of inulin), preferably more than 4 wt.%, more preferably more than 5 wt.%;

wherein more than 5 wt.% (by weight of inulin), preferably more than 8 wt.%, more preferably more than 12 wt.% of the inulin comprised in the aqueous liquid provided in step a) has a DP within the range of 3-5. Aaueous liquid comprising inulin

[0031] In embodiments, the chain length distribution of the GpyFn inulins comprised in the aqueous liquid provided in step a) has one, two, three, four, five or all of the following characteristics:

15-40%, preferably 20-35% of the GpyFn has a DP within the range of 3-10;

15-30%, preferably 18-28% of the GpyFn has a DP within the range of 1 1 -15;

10-25%, preferably 10-20% of the GpyFn has a DP within the range of 16-20;

5-20%, preferably 7-15% of the GpyFn has a DP within the range of 21 -25;

3-15%, preferably 5-10% of the GpyFn has a DP within the range of 26-30;

2-12%, preferably 3-8% of the GpyFn has a DP within the range of 31 -35;

1 -10%, preferably 2-6% of the GpyFn has a DP within the range of 36-40;

0.5-8%, preferably 0.5-4% of the GpyFn has a DP within the range of 41 -45;

0.5-10%, preferably 1 -6% of the GpyFn has a DP within the range of 46-64;

0.1 -4%, preferably 0.2-3% of the GpyFn has a DP of more than 64.

[0032] In preferred embodiments, the chain length distribution of the GpyFn inulins comprised in the aqueous liquid provided in step a) has all of the following characteristics:

• more than 10%, preferably more than 20% of the GpyFn inulins have a DP within the range of 3-10;

• more than 10%, preferably more than 20% of the GpyFn inulins have a DP of more than 15.

[0033] In embodiments, the GpyFn inulins comprised in the aqueous liquid provided in step a) have a chain length distribution wherein every DP within the range of 3-60, preferably within the range of 3-40, preferably within the range of 3-30 is present in an amount of at least 0.1 %, preferably at least 1 %.

[0034] As will be appreciated by those skilled in the art, the source of the inulin in the aqueous liquid provided in step a) is plant material comprising sesquiterpene lactones, such as lactucins. In preferred embodiments, the inulin provided in step a) of the methods and products provided herein is chicory inulin. Other sources of inulin that are encompassed by the invention include Globe Artichoke, amongst others.

[0035] In highly preferred embodiments, the source of the inulin in the aqueous liquid provided in step a) of the methods and the products provided herein is Cichorium intybus inulin. In an even more preferred embodiment, the source of the inulin in the aqueous liquid provided in step a) of the methods and products provided herein is Cichorium intybus L var. sativum, such as Cichorium intybus L. var. sativum DC.

[0036] In embodiments, the aqueous liquid provided in step a) comprises more than 3 wt.% (by weight of inulin), preferably more than 4 wt.% of minerals.

[0037] In embodiments the aqueous liquid provided in step a) comprises more than 3 wt.% (by weight of inulin), preferably more than 4 wt.% of organic acids, wherein the organic acids are preferably chosen from the group consisting of citric acid, malic acid, lactic acid, formic acid, acetic acid, propionic acid, butyric acid and combinations thereof.

[0038] In preferred embodiments, the aqueous liquid provided in step a) has not been subjected to ion-exchange treatment and/or active carbon filtration. [0039] In preferred embodiments, the aqueous liquid provided in step a) has not been subjected to ion-exchange treatment and active carbon filtration.

[0040] In preferred embodiments, the method for purifying the aqueous liquid comprising inulin in accordance with the invention does not comprise ion-exchange treatment and/or active carbon filtration. In preferred embodiments the method for purifying an aqueous liquid comprising inulin in accordance with the invention does not comprise ion-exchange treatment and active carbon filtration.

[0041] In a very preferred embodiment, the method as defined herein does not comprise ion- exchange treatment.

[0042] In an embodiment, the method as defined herein does not comprise an ion-exchange treatment and does comprise an active carbon treatment of the retentate obtained in step (c).

[0043] In a very preferred embodiment, the method as defined herein does not comprise a crystallization step.

[0044] In a very preferred embodiment, the method for purifying the aqueous liquid comprising inulin comprises the steps of:

a) providing an aqueous liquid comprising:

• lactucins in an amount of more than 0.1 wt.% (by weight of inulin), more preferably more than 0.3 wt.%;

• sugars in an amount of more than 3 wt.% (by weight of inulin), preferably more than 4 wt.%, more preferably more than 5 wt.%;

• more than 3 wt.% (by weight of inulin), preferably more than 4 wt.% of minerals; and

b) subjecting the aqueous liquid of step a) to a nanofiltration step employing a nanofiltration membrane having a molecular weight cut-off value of less than 2 kDa, preferably less than

1 .5 kDa, more preferably less than 1 .2 kDa, more preferably less than 1 .05 kDa; and c) collecting the retentate of nanofiltration step b) comprising:

• inulin, wherein more than 2% (by weight of inulin), preferably more than 4%, more preferably more than 6% of the inulin has a DP within the range of 3-5, said inulin comprising GpyFn inulins with a terminal glucose, wherein the GpyFn inulins have a chain length distribution wherein every DP within the range of 3-60 is present in an amount of at least 0.1 %, preferably at least 1 %; • less than 0.1 wt.% (by weight of inulin), preferably less than 0.05 wt.%, more preferably less than 0.01 wt.% of lactucins;

• less than 3 wt.% (by weight of inulin), preferably less than 2 wt.%, more preferably less than 1 .5 wt.% of sugars;

• less than 20 wt.% (by weight of inulin), preferably less than 10 wt.% (by weight of inulin), more preferably less than 5 wt.%, even more preferably less than 2 wt.% of FpyFn;

• more than 0.1 wt.% (by weight of inulin), preferably more than 0.8 wt.% of minerals; and

• more than 0.1 wt.% (by weight of inulin), preferably more than 0.8 wt.% of organic acids, wherein the organic acids are preferably chosen from the group consisting of citric acid, malic acid, lactic acid, formic acid, acetic acid, propionic acid, butyric acid and combinations thereof,

wherein the method does not comprise an ion-exchange treatment.

[0045] In highly preferred embodiments, less than 20 wt.% (by weight of inulin), preferably less than 10 wt.%, more preferably less than 5 wt.% of the inulin comprised in the aqueous liquid provided in step a) is FpyFn.

[0046] In embodiments, the inulin comprised in the aqueous liquid provided in step a) has a number-average degree of polymerization (DP) in the range of 3-60, preferably within the range of 5-30, preferably within the range of 8-13.

[0047] In embodiments, the method for purifying an aqueous liquid comprising inulin in accordance with the invention does not comprise a nanofiltration step before the nanofiltration of step b).

[0048] In embodiments, the method for purifying the aqueous liquid comprising inulin in accordance with the invention is provided wherein the aqueous liquid provided in step a) comprises less than 1 vol%, preferably less than 0.1 vol% of other solvents than water, such as alcohols. In embodiments the aqueous liquid provided in step a) is substantially free of other solvents than water, such as alcohols.

[0049] In preferred embodiments, the aqueous liquid provided in step a) and the inulin comprised therein have not been subjected to a hydrolysis treatment, such as an enzymatic hydrolysis treatment.

[0050] In embodiments, the aqueous liquid provided in step a) comprises more than 1 wt.% (by weight of aqueous liquid), preferably more than 5 wt.%, more preferably more than 10 wt.% of inulin.

[0051] In embodiments, the aqueous liquid provided in step a) comprises 1 -30 wt.%, preferably 5- 20 wt.%, more preferably 5-15 wt.% of inulin. A suitable method to determine the inulin content is by a chromatographic method, such as gel permeation chromatography coupled to a refractive index detector (GPC-RI). A preferred method to determine the inulin content is in accordance with the GPC-RI protocol described herein. Thus, in embodiments, the methods and products of the invention are provided, having the inulin content characteristics as described herein when determined in accordance with the GPC-RI protocol described herein. [0052] In embodiments, the aqueous liquid provided in step a) has a dry-matter content of more than 5 % (w/v), more preferably more than 10 %(w/v).

[0053] In embodiments, the aqueous liquid provided in step a) comprises more than 0.4 wt.% (by weight of inulin), preferably more than 0.6 wt.%, more preferably more than 0.8 wt.% of sesquiterpene lactones.

[0054] In embodiments, more than 10 wt.% (by weight of the sesquiterpene lactones), preferably more than 20 wt.% of the sesquiterpene lactones comprised in the aqueous liquid provided in step a) are lactucins.

[0055] In embodiments, the aqueous liquid provided in step a) comprises more than 6 wt.% (by weight of inulin), preferably more than 7 wt.%, more preferably more than 8 wt.% of sugars.

[0056] In embodiments the aqueous liquid provided in step a) comprises more than 0.05 wt.% (by weight of inulin), preferably more than 0.1 wt.% of polyphenols.

[0057] In embodiments, step a) comprises the following steps:

a1) providing a plant material comprising inulin, proteins, sugars and lactucins, preferably chicory root;

a2) subjecting the plant material to a processing step to provide an aqueous liquid comprising inulin, sugars, proteins, lactucins and processed plant material;

a3) separating the processed plant material and the aqueous liquid; and

a4) subjecting the aqueous liquid to a protein removal step wherein the proteins are at least partially removed to provide the aqueous liquid of step a).

[0058] Step a2) may be performed in many ways in order to provide an aqueous liquid comprising inulin, sugars, proteins and lactucins. In accordance with the invention, step a2) preferably comprises a processing step selected from the group consisting of thermal aqueous extraction, pulsed electric field treatment, increased pressure treatment, reduced pressure treatment, fermentation, acidification, freezing, size reduction, enzyme-assisted extraction, ultrasound treatment, microwave treatment, supercritical fluid extraction and combinations thereof. In very preferred embodiments, step a2) comprises a processing step selected from the group consisting of thermal aqueous extraction and/or pulsed electric field treatment.

[0059] In embodiments, step a2) comprises mashing the plant material, such as chicory roots, in order to make the aqueous liquid comprised in the plant material available for separation/collection.

[0060] In highly preferred embodiments, step a2) comprises contacting the plant material with an aqueous extraction liquid for an amount of time sufficient to at least partially extract the inulin. Thus, in preferred embodiments step a) comprises the following steps:

a1) providing a plant material comprising inulin, proteins, sugars and lactucins, preferably chicory root;

[0061] The extraction of step a2) may be performed on chopped, grinded, sliced or unsliced inulin- containing plant material, such as sliced chicory roots. In embodiments, the extraction of step a2) is performed on inulin-containing plant material slices with an average product thickness of 0.5-10 mm, preferably 1 -5 mm. The inulin-containing plant material may have been chopped, grinded or sliced by any suitable means known to the person skilled in the art, such as a drum slicer, a disc slicer, chopper or cutter. In preferred embodiments, the extraction step a2) is performed at a temperature within the range of 55-90 °C, preferably 65-75 °C. In preferred embodiments, the extraction step a2) is a counter-current extraction step. In embodiments, the aqueous extraction liquid comprises an alcohol, such as ethanol. Thus, in embodiments the aqueous liquid provided in step a) comprises an alcohol, such as ethanol.

[0062] Step a3) may be performed by any means known to the skilled person, such as pressing, decantation and/or filtration. For example, step a3) may be performed using a screw press or basket press equipped with a screen with suitable pore size, such as 0.1 -10 mm, preferably 0.5-5 mm, preferably 1 -2 mm.

[0063] Step a4), sometimes referred to in the art as a clarification step, may be performed by any means known to the skilled person, such as liming, carbonation, centrifugation, filtration and/or filtration with the aid of diatomaceous earth or siliceous earths. In preferred embodiments, step a4) comprises or consists of centrifugation and/or microfiltration. In highly preferred embodiments, step a4) comprises or consists of microfiltration.

[0064] In preferred embodiments, step a4) comprises lowering the protein content such that the aqueous liquid of step a) comprises less than 5 wt.% (by total weight of the inulin) protein, preferably less than 3 wt.%, more preferably less than 1 wt.% protein, wherein the protein content is determined using the Kjehldahl method with a conversion factor of 6.25.

[0065] As will be understood by the skilled person, the nanofiltration of step b) may be preceded at any point in the method of the invention by a coarse physical purification step to remove large particles such as filtration. Thus, in preferred embodiments, step a) further comprises a coarse physical purification step. In embodiments the coarse physical purification step comprises filtration using a screen with aperture larger than 50 pm, preferably larger than 90 pm, preferably larger than 100 pm.

Nanofiltration step

[0066] The nanofiltration membrane employed in step b) of the method in accordance with the invention may be provided in any form known to the person skilled in the art, preferably in the form of a flat sheet, hollow-fiber, tubular or spiral wound membrane.

[0067] In preferred embodiments, the nanofiltration membrane employed in step b) has a molecular weight cut-off value of more than 0.3 kDa, preferably more than 0.4 kDa, more preferably more than 0.5 kDa. [0068] In embodiments, the nanofiltration membrane employed in step b) has a molecular weight cut-off value of more than 0.5 kDa, more than 0.6 kDa, more than 0.7 kDa, more than 0.8 kDa, or more than 0.9 kDa.

[0069] In embodiments, the nanofiltration membrane employed in step b) has a molecular weight cut-off value of less than 1 .9 kDa, less than 1 .8 kDa, less than 1 .7 kDa, less than 1 .6 kDa, less than 1 .5 kDa, less than 1 .4 kDa, less than 1 .3 kDa, less than 1 .2 kDa or less than 1 .1 kDa.

[0070] In highly preferred embodiments, the nanofiltration membrane employed in step b) has a molecular weight cut-off value of about 1 kDa, preferably of 1 kDa.

[0071] In embodiments, the nanofiltration membrane employed in step b) has a molecular weight cut-off value within the range of 0.5-1 .5 kDa, preferably within the range of 0.8-1 .2 kDa, more preferably within the range of 0.95-1 .05 kDa.

[0072] In embodiments, the nanofiltration membrane employed in step b) has a molecular weight cut-off value within the range of 0.5-1 .2 kDa, preferably within the range of 0.6-0.8 kDa.

[0073] In embodiments, the nanofiltration membrane employed in nanofiltration step b) comprises or consists of one or more polymers selected from the group consisting of polyamide (PA), polysulfone (PS), polyethersulfone (PES), polyimide and polypiperazine, preferably polyamide (PA) or polypiperazine.

[0074] In a very preferred embodiment, the nanofiltration membrane has a narrow pore size distribution, such as a pore size distribution having pores with diameters D characterized by a span = (D90-D10VD50 of below 0.1 , preferably below 0.05.

[0075] In embodiments, the nanofiltration membrane employed in step b) is a ceramic membrane.

[0076] In embodiments, the nanofiltration membrane employed in step b) comprises or consists of a thin-film composite membrane, preferably a thin-film composite membrane comprising polyamide or polypiperazine.

[0077] In embodiments, the nanofiltration membrane employed in step b) is capable of achieving a membrane selectivity S of more than 5, preferably more than 8, preferably more than 12.

[0078] As used herein the membrane selectivity S is defined as follows:

wherein

S is the membrane selectivity;

Cm is the inulin concentration in the retentate stream (wt.% based on the weight of the retentate); Cs _Lr is the sesquiterpene lactones concentration in the retentate stream (wt.% based on the weight of the retentate);

Cip is the inulin concentration in the permeate stream (wt.% based on the weight of the permeate); and

Cs _Lp is the sesquiterpene lactones concentration in the permeate stream (wt.% based on the weight of the permeate). [0079] In embodiments, the nanofiltration membrane is capable of achieving the membrane selectivity S as defined herein at a temperature within the range of 10-70 °C, preferably 40-60 °C, a flux within the range of 10-60 l/(m ²*hour), preferably 20-40 l/(m ²*hour) and a transmembrane pressure within the range of 5-40 bar, preferably 10-25 bar.

[0080] In embodiments, step b) is performed such that the transmembrane pressure is more than 2 bar, for example in the range of 5-30 bar. In preferred embodiments step b) is performed such that the transmembrane pressure is more than 6 bar, more than 10 bar, more than 20 bar, or more than 40 bar.

[0081] In preferred embodiments, the nanofiltration in step b) is performed as a diafiltration. As is known to the skilled person, a nanofiltration step results in a feed stream being separated into a retentate stream and a permeate stream. Diafiltration is an operating mode of nanofiltration wherein the retentate stream is recirculated and added to the feed stream, and solvent, preferably demineralized water, is added to the feed stream to compensate for the permeate losses. Addition of a volume of solvent, preferably demineralized water, equal to the volume of feed is referred to as 1 washing volume, indicated as W/F=1 . In preferred embodiments, the nanofiltration in step b) is performed as a diafiltration using demineralized water, wherein W/F is in the range of 1 -8, preferably, W/F is in the range of 2-6, more preferably W/F is in the range of 4.5-5.5. In preferred embodiments, the nanofiltration in step b) is performed as a diafiltration using demineralized water, wherein W/F is in the range of 1 -7, preferably, W/F is in the range of 1 -4, more preferably W/F is in the range of 1 .5-3.5.

[0082] In preferred embodiments, the nanofiltration in step b) is performed at a feed temperature within the range of 20-80 °C, preferably within the range of 30-70 °C, more preferably within the range of 35-55 °C, most preferably within the range of 40-50 °C.

[0083] In embodiments, the nanofiltration in step b) is performed at a feed temperature of more than 50 °C, preferably of more than 60 °C, more preferably of more than 70 °C.

[0084] In embodiments, the nanofiltration in step b) employs measures to prevent fouling of the membrane, such as cross-flow filtration, mechanical agitation, increasing the shear or turbulence of the feed at the membrane surface.

[0085] The present inventors have found that the methods in accordance with the invention advantageously allow the retention of low amounts of polyphenols, and substantial amounts of organic acids or nutrients in the form of minerals as defined herein. As will be shown in the appended examples, the amount of polyphenols, organic acids and/or nutrients retained is low enough to provide a product with desirable organoleptic and/or colour properties, while the amount may be sufficient to impart one or more beneficial effects to the composition. For example, low amounts of polyphenols may have an anti-inflammatory and/or anticarcinogenic effect; low amounts of organic acids may have a preservative effect; and low amounts of minerals may serve as (micro)nutrients. Retentate

[0086] In embodiments, the retentate collected in step c) comprises more than 1 wt.% (by weight of retentate), preferably more than 5 wt.% of inulin. In embodiments, the retentate collected in step c) comprises 1 -20 wt.% (by weight of retentate), preferably 2-15 wt.%, more preferably 4-8 wt.% of inulin.

[0087] In embodiments, the retentate collected in step c) has a dry-matter content of more than 5% (w/v), more preferably more than 8% (w/v).

[0088] In embodiments, more than 2 wt.% (by weight of inulin), preferably more than 4 wt.%, more preferably more than 6 wt.% of the inulin comprised in the retentate collected in step c) has a DP within the range of 3-5.

[0089] In highly preferred embodiments, less than 20 wt.% (by weight of inulin), preferably less than 10 wt.%, more preferably less than 5 wt.%, even more preferably less than 2 wt.% of the inulin comprised in the retentate collected in step c) is FpyFn.

[0090] In embodiments, the inulin comprised in the retentate collected in step c) has a number- average degree of polymerization in the range of 3-60, preferably within the range of 5-30, preferably within the range of 8-13.

[0091] In embodiments the chain length distribution of the GpyFn comprised in the retentate collected in step c) has one, two, three, four, five or all of the following characteristics: