Modified starch and methods and uses related thereto

Abstract

The invention relates to methods of manufacturing modified starch compositions using thermomechanical degradation. The invention also relates, inter alia, to compositions obtainable by the methods of the invention; products such as food items, feed items, thickening agents, adhesives, cosmetic products, paper, or construction materials, comprising said compositions; and uses and various applications of said compositions.

Description

[0001] P137950PC00

[0002] Title: MODIFIED STARCH AND METHODS AND USES RELATED THERETO

[0003] FIELD

[0004] The invention relates to the field of food technology and starch applications. More in particular, it relates to modified starches.

[0005] BACKGROUND

[0006] Starch is the most common carbohydrate in human diets. It contains polymers of glucose that are connected via glycosidic bonds. Starch usually consists of two types of molecules: amylose (which is normally linear and helical), and amylopectin (which is typically branched). Major sources of starch include, but are not limited to, root vegetables (particularly potatoes and cassava) and cereals (such as rice, wheat, and maize).

[0007] Native granular starch is typically insoluble in cold water or alcohol, and can be processed in various ways to obtain starch compositions having a wide range of different properties, such as viscosity, water solubility, gel formation, and the like.

[0008] One of these ways in which starch has been processed is by chemically modifying the starch so as to obtain a modified starch. These modifications typically serve to enhance the performance of the starch in several applications, for example to decrease or increase their viscosity; to increase their stability against excessive heat, acid, shear, time, cooling, or freezing; to change their texture; to lengthen or shorten gelatinization time, and / or to increase their visco-stability.

[0009] However, modifying starch typically requires some pretreatment. For instance, in some applications the starch is thermomechanically degraded in the presence of a starch-modifying agent. Then, the native granular starch is typically subjected to a pretreatment prior to said thermomechanical degradation. The pretreatment comprises for example hydrolysis (by enzymes, acids, and / or bases), and usually aims to prepare the starch granules by disrupting their crystalline structure, increasing their surface area, and / or making them more accessible or reactive to chemical, physical, or enzymatic agents. Other forms of pretreatment include physical pretreatment and thermal pretreatment. Thus, it is a typical disadvantage of pretreatment that it involves the use of chemicals, and / or requires time and / or energy.

[0010] Moreover, depending on the modification process catalysts may be considered necessary to speed up the reaction between the starch and the starch-modifying agent.

[0011] Thus, there is a desire to provide methods of modifying starch that allow the avoidance of any pretreatment. In particular, there is a desire to provide methods of modifying starch that are more environmentally friendly, viz. that reduce or avoid the need for chemicals (used for pretreatment or as catalysts) and / or energy. Moreover, it is desired that methods of modifying starch be provided that allow a shorter period of time necessary to prepare the modified starch.

[0012] There is thus a need for methods of modifying starch that address one or more of the abovementioned problems and / or desires.

[0013] SUMMARY

[0014] In one aspect, the invention relates to a method for providing a modified starch composition, wherein the method comprises the steps of: (a) providing a starting composition of a native granular starch, wherein the starting composition has a moisture content in a range of from 15 to 35 wt.% relative to the total weight of the starting composition, and wherein said native granular starch has not been subjected to any pretreatment; preferably the starting composition is free of any non-starch additives; more preferably the starting composition is free of any additives; (b) subjecting the starting composition to thermomechanical degradation by an extrusion process in an extruder barrel; wherein the extrusion process is performed in the presence of at least one starch-modifying agent to modify the starch in situ, and (c) obtaining and optionally drying the extrudate and / or subjecting the extrudate to a step of particle size reduction.

[0015] The invention also pertains to a modified starch composition obtainable by the method according to the invention.

[0016] The invention further relates to a food item, a feed item, a thickening agent, an adhesive, a cosmetic product, paper, or a construction material, comprising a modified starch composition obtainable by the method of the invention.

[0017] The invention additionally pertains to the use of a modified starch composition according to the invention as a food ingredient, a feed ingredient, a thickening agent, an adhesive, an ingredient for a cosmetic product, as an ingredient for the production of paper, and / or as a component of a construction material.

[0018] DETAILED DESCRIPTION

[0019] The invention is based on the judicious insight that modified starch compositions can be manufactured in a sustainable and “green” fashion by subjecting native granular starch to a thermomechanical degradation process, preferably an extrusion process, in the presence of at least one starch-modifying agent and water. In particular, the methods of the invention allow the avoidance of any pretreatment of the starch prior to thermomechanical degradation. Moreover, methods of the invention are more environmentally friendly than known processes, and in particular allow the reduction or avoidance of chemicals and / or energy. Furthermore, methods of the invention allow a shorter period of time necessary to prepare the modified starch, in particular because any pretreatment of the starch can be dispensed with.

[0020] Without wishing to be bound by theory, the inventors believe that surprisingly, the conditions during the thermomechanical degradation may achieve the same goals usually pursued by pretreatment, viz. disrupting the crystalline structure of the native starch granules, increasing the surface area of the native starch, and / or making the starch more accessible and / or reactive to starch-modifying agents. In particular, the pressure, temperature, and / or energy applied on the starch in thermomechanical degradation is believed to contribute hereto. Still without wishing to be bound by theory, the inventors believe that the formation of very reactive species, for example free radicals or oxidative species, during thermomechanical degradation may act as highly energetic initiators.

[0021] Startins composition

[0022] In step (a) of the method of the invention, a starting composition is provided. The starting composition comprises native granular starch and water.

[0023] As used herein, “native granular starch” refers to starch that is in its natural, unmodified form as it is extracted from a plant source. In this state, the starch granules typically retain their original crystalline and molecular structure as formed in the plant, which may include a specific arrangement and amount of amylose and amylopectin molecules.

[0024] In principle, any type of starch can be used in the methods of the invention.

[0025] Preferably, the native granular starch is a starch selected from the group consisting of waxy starch, amylose starch, and regular starch. More preferably, the native granular starch is selected from the group consisting of corn starch, potato starch, tapioca starch, faba starch, pea starch, wheat starch, arrowroot starch, sweet potato starch, yam starch, taro starch, and combinations thereof. More preferably, the native granular starch is potato starch, com starch, tapioca starch, faba starch, or a combination thereof. Even more preferably, the native granular starch is potato starch, com starch, tapioca starch, or a combination thereof. Even more preferably, the native granular starch is potato starch or tapioca starch. More preferably still, the native granular starch is potato starch. Most preferably, the native granular starch is native potato starch.

[0026] As used herein, “potato” refers to a plant of the species Solanum tuberosum.

[0027] As used herein, “tapioca starch” refers to starch extracted from the tubers of the cassava plant. As used herein, “cassava” refers to a plant of the genus Mani hot.jand includes the species Manihot esculenta, syn. M. utilissima, also called manioc, mandioca or yuca, and also M. palmata, syn. M. dulcis. Cassava is also known as manioc, mandioca, or yuca.

[0028] As used herein, “com” refers to a plant of the species Zea mays.

[0029] As used herein, “faba” refers to a plant of the species Vicia faba.

[0030] As used herein, “pea” refers to the seed of a plant of the species Pisum sativum (also known as Lathyrus ole race us). Cajanus cajan (pigeon pea), or Vigna unguiculata (cowpea); preferably Pisum sativum.

[0031] As used herein, “wheat” refers to a plant of the genus Triticim preferably of the species Triticum aestivum (common wheat).

[0032] As used herein, “arrowroot starch” refers to starch obtained from the rhizomes plant of the species Maranta arundinacea. Tacca leontopetaloides, or Canna indica: preferably Maranta arundinacea.

[0033] As used herein, “sweet potato” refers to a plant of the species Ipomoea batatas. As used herein, “yam” refers to a plant of the genus Dioscorea.

[0034] As used herein, “taro” refers to a plant of the species Colocasia esculenta. Preferably, the native granular starch comprises at least 55 wt% of amylopectin, more preferably at least 60 wt%, more preferably at least 65 wt%, and most preferably at least 70 wt%. Preferably, the native granular starch comprises amylopectin in an amount in a range of from 55 to 99 wt%, more preferably from 60 to 98 wt%, more preferably from 65 to 97 wt%, and most preferably from 70 to 95 wt%.

[0035] Preferably, the native granular starch comprises at most 45 wt% of amylose, more preferably at most 40 wt%, more preferably at most 35 wt%, and most preferably at most 30 wt%. Preferably, the native granular starch comprises amylose in an amount in a range of from 1 to 45 wt%, more preferably from 2 to 40 wt%, more preferably from 3 to 35 wt%, and most preferably from 5 to 30 wt%.

[0036] The starting composition may have a moisture content in a range of from 10 to 50 wt%, and typically of from 15 to 35 wt.%, more commonly of from 17 to 32 wt%, relative to the total weight of the starting composition. Preferably, said starting composition has a moisture content in a range of from 18 to 30 wt%, more preferably of from 19 to 28 wt.%, and most preferably of from 20 to 25 wt%, relative to the total weight of the starting composition.

[0037] Preferably, the starting composition comprises the native granular starch in an amount of at least 60 wt%, more preferably at least 65 wt%, more preferably at least 70 wt%, more preferably at least 72 wt%, more preferably at least 75 wt%, and most preferably at least 77 wt%, as compared to the total weight of the starting composition.

[0038] In methods of the invention the native granular starch has not been subjected to any pretreatment. This may reduce the time required for the starch modification process, may reduce the energy required for said process, and may reduce the need for chemicals (or decrease the amount of chemicals required for said process).

[0039] As used herein, “pretreatmenf ’ typically refers to any chemical treatment that chemically modifies the native granular starch. Preferably, “pretreatmenf ’ refers to any chemical, physical, and / or thermal treatment that chemically, physically, and / or thermally modifies and / or degrades the native granular starch. More preferably, “pretreatmenf’ is any treatment that disrupts the crystalline structure of the native granular starch, increases the surface area of the native granular starch, makes the starch more accessible and / or reactive to starch-modifying agents, and / or chemically modifies the native granular starch.

[0040] In this context, it will be understood that “pretreatment” does not include contacting the native granular starch with a starch-modifying agent if this contacting does not lead to chemical modification of the native granular starch, for example because both the native granular starch and the starch-modifying agent are present as solids, and no chemical reaction can occur.

[0041] Preferably, the starting composition is free of any non-starch additives; and more preferably the starting composition is free of any additives. As used in this context, “additives” relates to any compound other than native granular starch, starch-modifying agents, and water. In particular, “additives” may refer to colorants, plasticizers (such as glycerol and sorbitol), stabilizers, emulsifiers (such as lecithin and monoglycerides), antioxidants (such as ascorbic acid), preservatives (such as sodium benzoate and potassium sorbate), and fillers (such as cellulose and maltodextrin).

[0042] Furthermore, “additives” may also refer to catalysts. Preferably, the starting composition is substantially free of catalysts. As used herein, a “catalyst” is any substance that increases the reaction rate of the reaction between the starch and the starch-modifying agent, and is itself not consumed by the reaction.

[0043] The starting composition may comprise the at least one starch-modifying agent, provided that contacting the native granular starch and the at least one starch-modifying agent does not chemically modify the native granular starch before the native granular starch is introduced to the extruder barrel in which the extrusion process is performed.

[0044] However, it is more preferred that the starting composition does not comprise the at least one starch-modifying agent. In that case, the at least one starch-modifying agent is contacted with the starting composition in the extruder barrel, which can be done immediately before the extrusion process is started, simultaneously with starting the extrusion process, and / or during the extrusion process by feeding the at least one starch- modifying agent into the extruder barrel. Said feeding may be continuous or discontinuous, but continuous feeding is preferred.

[0045] If the starting composition comprises the at least one starch-modifying agent, it is preferred that said starch-modifying agents are present in a total amount in a range of from 0.001 to 15 wt%, preferably from 0.01 to 5 wt%, more preferably in a range of from 0.10 to 3 wt%, more preferably in a range of from 0.20 to 2 wt%, more preferably in a range of from 0.30 to 1.5 wt%, and most preferably in a range of from 0.40 to 1.20 wt%, as compared to the dry weight of the native granular starch.

[0046] Consequently, it is preferred that the starting composition essentially consists of the native granular starch, water, and the at least one starch-modifying agent. More preferably, the starting composition essentially consists of the native granular starch, and water. In the latter case, it is preferred that no other reagents than the at least one starch-modifying agent and optionally water are contacted with the starting composition immediately before or during the thermomechanical degradation.

[0047] As used herein, “essentially consists of’ indicates that the components make up at least 95 wt% as compared to the total weight of the starting composition, preferably at least 96 wt%, more preferably at least 97 wt%, more preferably at least 98 wt%, more preferably at least 99 wt%, more preferably at least 99.5 wt%, more preferably at least 99.9 wt%, and most preferably about 100 wt%.

[0048] If the starting composition comprises multiple components, the starting composition can be provided by contacting the required components, for example by mixing, blending, shaking, stirring, and the like. Contacting the required components may be performed prior to introducing the starting composition to the extruder, in particular immediately before introducing the starting composition to the extruder, and / or the contacting can take place in the extruder. Contacting the required components may be carried out immediately before the extrusion process is started.

[0049] Thermomechanical degradation

[0050] In step (b) of methods of the invention the starting composition is subjected to thermomechanical degradation by an extrusion process. The extrusion process takes place in an extruder barrel, and is carried out in the presence of at least one starch- modifying agent to modify the native granular starch in situ. Preferably, during the extrusion process a melt is formed, wherein the melt exits the extruder barrel through a die to provide an extrudate.

[0051] In particular, the starch-modifying agent typically results in chemical modification of the native granular starch in situ. Advantageously, however, the thermomechanical degradation may chemically and physically alter the native granular starch as well. Without wishing to be bound by theory, the thermomechanical degradation may degrade the native granular starch by breaking up the glycosidic bonds within the native granular starch, so as to make the starch more accessible and / or more reactive towards the at least one starch-modifying agent.

[0052] As noted above, the at least one starch-modifying agent may be comprised in the starting composition, and / or may be contacted with the starting composition directly before the extrusion process is started, simultaneously with starting the extrusion process, and / or during the extrusion process. Preferably, the at least one starch- modifying agent is contacted with the starting composition during the extrusion process. In that case, it is preferred that the at least one starch-modifying agent is continuously fed into the extruder barrel.

[0053] The amount of the at least one starch-modifying agent used in methods of the invention may depend on which starch-modifying agent is employed. The skilled person is readily aware of suitable amounts and concentrations to be used. For example, the at least one starch-modifying agent is present in an amount in a range of from 0.01 to 5 wt%, preferably in a range of from 0.10 to 3 wt%, more preferably in a range of from 0.20 to 2 wt%, more preferably in a range of from 0.30 to 1.5 wt%, and most preferably in a range of from 0.40 to 1.20 wt%, wherein the wt% is relative to the weight of the starting composition. It will be understood that the starch-modifying agents are consumed when reacting with the native granular starch. Thus, herein the amount of the at least one starch-modifying agent refers to the amount directly before it is contacted with the starting composition, for example at the start of the extrusion process.

[0054] Preferably, at most three different starch-modifying agents are used in a method of the invention. More preferably, at most two different starch-modifying agents are used in a method of the invention. Most preferably, only one starch-modifying agent is used in a method of the invention.

[0055] Preferably, the at least one starch-modifying agent is selected from the group consisting of crosslinkers, hydrolyzing agents, oxidizing agents, etherification agents, esterification agents, grafting agents, and phosphorylation agents.

[0056] Preferably, the at least one starch-modifying agent is at least one crosslinker, more preferably only one crosslinker. The crosslinker is preferably selected from the group consisting of citric acid, a trimetaphosphate salt, epichlorohydrin, phosphorus oxychloride (POCh), a tripolyphosphate salt, an anhydride, a hypochlorite salt, and a pyrophosphate salt. More preferably, the crosslinker is selected from the group consisting of a trimetaphosphate salt, epichlorohydrin, phosphorus oxychloride (POCh), a tripolyphosphate salt, an anhydride, a hypochlorite salt, and a pyrophosphate salt. The salts mentioned herein are preferably sodium salts. Thus, the trimetaphosphate salt is preferably sodium trimetaphosphate (NasPsC ); the tripolyphosphate salt is preferably sodium tripolyphosphate (NasPsOio); and the pyrophosphate salt is preferably tetrasodium pyrophosphate (Na4P2O?). Preferably, the anhydride is adipic anhydride.

[0057] In other preferred embodiments, the at least one starch-modifying agent is at least one hydrolyzing agent, more preferably only one hydrolyzing agent. Preferably, the hydrolyzing agent is selected from the group consisting of acidic hydrolysis agents, enzymatic hydrolysis agents, and oxidative hydrolysis agents. Preferably, the acidic hydrolysis agent is selected from the group consisting of hydrochloric acid, sulfuric acid, and nitric acid. Preferably, the enzymatic hydrolysis agent is selected from the group consisting of a-amylase, B-amylase, glucoamylase (also known as amyloglucosidase), pullulanase, and isoamylase; more preferably the enzymatic hydrolysis agent is a-amlyase. Preferably, the oxidative hydrolysis agent is hydrogen peroxide (H2O2) or potassium permanganate (KMnC ).

[0058] In other preferred embodiments, the at least one starch-modifying agent is at least one oxidizing agent, more preferably only one oxidizing agent. Preferably, the oxidizing agent is selected from the group consisting of sodium hypochlorite, hydrogen peroxide, potassium permanganate, ozone, sodium periodate, and nitrogen dioxide. It will be understood that hydrogen peroxide and potassium permanganate may also function as an oxidative hydrolysis agent.

[0059] In other preferred embodiments, the at least one starch-modifying agent is at least one etherification agent, more preferably only one etherification agent. Preferably, the etherification agent is selected from the group consisting of ethylene oxide, propylene oxide, chloroacetate, epichlorohydrin, and quaternary ammonium compounds. More preferably, the etherification agent is chloroacetate or epichlorohydrin. Most preferably, the etherification agent is chloroacetate. Preferably, a salt of chloroacetate is used, preferably sodium monochloroacetate.

[0060] In other preferred embodiments, the at least one starch-modifying agent is at least one esterification agent, more preferably only one esterification agent. Preferably, the esterification agent is selected from the group consisting of anhydrides, carboxylic acids, alcohols, halides, phosphoric acid, and fatty acids. Preferably, the anhydride is acetic anhydride, propionic anhydride, or octenylsuccinic acid. Preferably, the carboxylic acid is acetic acid or butyric acid. Preferably, the alcohol is ethanol or glycerol. Preferably, the halide is an acyl chloride, more preferably acetyl chloride. Preferably, the fatty acid is a long-chain fatty acid, more preferably the fatty acid is selected from the group consisting of lauric acid, stearic acid, myristic acid, palmitic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, and melissic acid; even more preferably the fatty acid is lauric acid or stearic acid.

[0061] In other preferred embodiments, the at least one starch-modifying agent is at least one grafting agent, more preferably only one grafting agent. Preferably, the grafting agent is selected from the group consisting of acrylates, methacrylates, acrylamides, methacrylamides, vinyl compounds, polyethylene glycol, chitosan, polysaccharides, and functionalized silanes. Preferably, the acrylate is selected from the group consisting of acrylic acid, methyl acrylate, ethyl acrylate, 2-chloroethyl vinyl ether, 2-ethylhexyl acrylate, butyl acrylate, and trimethylolpropane triacrylate; more preferably the acrylate is acrylic acid or methylacrylate. Preferably, the methacrylate is selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, and glycidyl methacrylate; more preferably the methacrylate is methyl methacrylate. Preferably, the vinyl compound is vinyl acetate or styrene. Preferably, the polyethylene glycol has a molecular weight in a range of from 200 Da to 100 kDa, more preferably of from 500 Da to 75 kDa, more preferably of from 1 kDa to 50 kDa, even more preferably of from 2 kDa to 35 kDa, and most preferably of from 5 kDa to 25 kDa. Preferably, the polysaccharide is guar gum or xanthan gum. Preferably, the functionalized silane is vinyltriethoxysilane, 3 -aminopropyltri ethoxy silane, 3- methacryloxypropyltrimethoxysilane, glycidyloxypropyltrimethoxysilane, and chi oropropy Itri ethoxy sil ane .

[0062] In other preferred embodiments, the at least one starch-modifying agent is at least one phosphorylating agent, more preferably only one phosphorylating agent. Preferably, the phosphorylating agent is selected from the group consisting of phosphoric acid, sodium phosphate compounds, phosphoryl chloride, phosphorus pentoxide, aminophosphonates, alkyl phosphate esters, and phosphorylating enzymes. Preferably, the sodium phosphate compound is sodium dihydrogen phosphate or di sodium hydrogen phosphate. Preferably, the aminophosphonate is aminotrimethylenephosphonic acid. Preferably, the alkyl phosphate ester is tributyl phosphate. Preferably, the phosphorylating enzyme is selected from the group consisting of starch phosphorylase, phytase, glucose-6-phosphate dehydrogenase, nucleotide sugar-dependent glycosyltransferases, hexokinase, and starch synthase.

[0063] Thus, preferably the at least one starch-modifying agent is selected from the group consisting of citric acid, epichlorohydrin, sodium trimetaphosphate (NasPrC ), sodium tripolyphosphate (NasPrOio), tetrasodium pyrophosphate (Na4P2O?), adipic anhydride, hydrochloric acid, sulfuric acid, nitric acid, a-amylase, B-amylase, glucoamylase (also known as amyloglucosidase), pullulanase, isoamylase, hydrogen peroxide (H2O2), potassium permanganate (KMnC ), sodium hypochlorite, ozone, sodium periodate, and nitrogen dioxide, ethylene oxide, propylene oxide, epichlorohydrin, quaternary ammonium compounds, sodium monochloroacetate, phosphoric acid, acetic anhydride, propionic anhydride, octenylsuccinic acid, acetic acid, butyric acid, ethanol, glycerol, acetyl chloride, lauric acid, stearic acid, myristic acid, palmitic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, acrylamide, methacrylamide, polyethylene glycol, chitosan, acrylic acid, methyl acrylate, ethyl acrylate, 2-chloroethyl vinyl ether, 2-ethylhexyl acrylate, butyl acrylate, trimethylolpropane triacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, glycidyl methacrylate, vinyl acetate, styrene, guar gum, xanthan gum, vinyltri ethoxy silane, 3 -aminopropyltri ethoxy silane, 3- methacryloxypropyltrimethoxysilane, glycidyloxypropyltrimethoxysilane, chloropropyltriethoxysilane, phosphoryl chloride, phosphorus pentoxide, sodium dihydrogen phosphate, di sodium hydrogen phosphate, aminotrimethylenephosphonic acid, tributyl phosphate, starch phosphorylase, phytase, glucose-6-phosphate dehydrogenase, nucleotide sugar-dependent glycosyltransferases, hexokinase, and starch synthase. Preferably, a minimum number of ingredients is used in the method of the invention. This ensures the most environmentally friendly method as possible. As such, it is preferred that during the extrusion process no substances are introduced to the extruder barrel other than the starting composition, the at least one starch-modifying agent, and optionally water. It will be understood that as used in the previous sentence, “substances” preferably does not include air. Consequently, it is preferred that during the extrusion process no substances are introduced to the extruder barrel other than the starting composition, the at least one starch-modifying agent, air, and optionally water. As noted above, the at least one starch-modifying agent and water may also be present in the starting composition. In that case, it is preferred that only the starting composition is provided to the extruder barrel, and optionally additional water.

[0064] The additional water may be fed continuously into the extruder barrel to maintain the moisture content of the composition during extrusion (herein referred to as the “extrusion mass” or “melt”) at a desired level. The water may be introduced to the extruder barrel in the form of steam. Preferably, the moisture content of the extrusion mass is in a range of from 10 to 50 wt%, relative to the total weight of the extrusion mass, more preferably of from 15 to 35 wt%, more preferably of from 17 to 32 wt%, more preferably of from 18 to 40 wt%, even more preferably of from 19 to 30 wt%, and most preferably of from 20 to 27 wt%.

[0065] Preferably, the extrusion process in the methods of the invention is a single-step extrusion process.

[0066] Preferably, an extrusion setup used in the extrusion process of methods of the invention comprises an extruder comprising a barrel section comprising at least 3 blocks, preferably at least 5 blocks, the first block of the barrel section comprising a feed inlet adapted for feeding the feed composition into the extruder, the second block, located downstream of the first block of the barrel section, comprising a water inlet adapted for introducing water and / or steam into the extruder, and one or more further downstream blocks adapted to setting the temperature along the barrel section to comprise an increasing temperature gradient, said extruder further comprising a die section located downstream of the barrel section, and one or more screw elements adapted to convey the feed composition through the barrel section to the die section. The first block in the barrel section comprises a feed inlet, adapted for feeding a feed composition as herein defined into the extruder. The second block in the barrel section, located downstream of the first block, comprises a water inlet, adapted for introducing water and / or steam into the extruder so as to attain the desired moisture content of the melt. The first and the second block are preferably operated under more or less ambient conditions (20 - 30 °C). One or more further downstream blocks in the barrel section are preferably equipped with means for heating and cooling, so as to allow for setting the temperature along the barrel section to comprise an increasing temperature gradient. In preferred embodiments, the temperature increases stepwise to a maximum temperature of 100 - 250 °C, more preferably 130 - 180 °C, even more preferably 140 - 160 °C.

[0067] Although the barrel section must comprise an increasing temperature gradient, it is conceivable that in some setups, the barrel section may comprise one or more barrel parts in which there is a decreasing temperature gradient, or a constant temperature. Such barrel parts may be combined with for example one, two or more barrel parts with an increasing temperature gradient, as the skilled person appreciates.

[0068] The barrel section furthermore comprises a die section located downstream of the barrel section, and one or more screw elements adapted to convey the feed composition through the barrel section to the die section. In preferred embodiments, the barrel section is equipped with a co-rotating twin screw. Further preferably, the screw configuration comprises reversed pitch elements and conveying elements, preferably alternatingly. In further preferred embodiments, the screw configuration comprises 2 - 10 reversed pitch elements. Reversed pitch elements are preferably located of from 10 D to 20 D. In much preferred embodiments, a reversed pitch element, preferably the reversed pitch element is followed downstream by a kneading block, preferably having a stagger angle of between 30° and 60°, most preferably between 30° and 45°. In further preferred embodiments, the die section comprises a die having one, or two or multiple outlets, preferably one or two outlets, through which outlet(s) the extruded feed mass exits the extruder.

[0069] During the extrusion process several conditions such as pressure, the temperature of the melt at the die of the extruder, and specific mechanical energy (SME) may be employed. Furthermore, the barrel temperature during extrusion may also be specified. As the skilled person is aware, the barrel temperature may not be the same as the temperature of the melt during extrusion (in particular at the die of the extruder). The friction exerted on the extrusion mass may increase the melt temperature as compared to the barrel temperature. Simultaneously, depending on the extruder design, at high throughputs the melt may not spend sufficient time in a barrel section to attain the temperature of the barrel section. At any rate, the skilled person is aware how to tune the extrusion conditions (in particular the throughput, moisture content, barrel temperature, and pressure) to achieve the desired temperature of the melt at the die of the extruder.

[0070] Unless indicated otherwise, as used herein “melt” or “extrusion mass” refers to the composition in the extruder barrel during the extrusion process. It will be understood that the melt or extrusion mass has already been subjected to the extrusion process to such an extent that it differs from the starting composition.

[0071] Unless indicated otherwise, as used herein “SME” (in kWh / kg) is the specific mechanical energy transferred from the extruder to the starting composition; P (in bar) is the pressure at the die of the extruder; and T (in °C) is the melt temperature at the die of the extruder. The skilled person is aware how to tune the extrusion conditions (in particular the throughput, moisture content, barrel temperature, pressure, screw speed, and torque) to achieve the desired SME during extrusion.

[0072] The barrel temperature may be denoted as TB. Preferably, TB or the phrase “temperature in a barrel section” or similar phrasing refers to the temperature in the barrel section of an extruder immediately preceding the die of said extruder, for example the sixth barrel section in exemplary extruders as described herein.

[0073] Preferably, the pressure P is in a range of from 1 to 90 bar, more preferably of from 2 to 70 bar, more preferably of from 3 to 60 bar, more preferably of from 5 to 55 bar, more preferably of from 7 to 50 bar, more preferably of from 9 to 45 bar, and most preferably of from 10 to 40 bar. Exemplary values for pressure P include about 39 bar, about 38 bar, about 31 bar, about 30 bar, about 24 bar, about 20 bar, about 16 bar, about 14 bar, about 13 bar, about 12 bar, about 11 bar, about 7 bar, about 6 bar, and about 3 bar.

[0074] Preferably, the temperature of the extrusion barrel during the extrusion process is in a range of from 120 to 180 °C, more preferably of from 125 to 170 °C, and most preferably of from 130 to 165 °C.

[0075] Preferably, the temperature of the extrusion mass at the die of the extruder is in a range of from 120 to 180 °C, more preferably of from 125 to 170 °C, and most preferably of from 130 to 165 °C. Exemplary values for the melt temperature at the die of the extruder are about 154 °C, about 155 °C, about 162 °C, about 169 °C, about 160 °C, about 167 °C, about 147 °C, about 148 °C, about 156 °C, about 145 °C, about 151 °C, and about 159 °C.

[0076] Preferably, the SME during the extrusion process is at least 0.05 kWh / kg. More preferably, the SME is in a range of from 0.05 to 0.50 kWh / kg, more preferably of from 0.07 to 0.35 kWh / kg, more preferably of from 0.08 to 0.30 kWh / kg, more preferably of from 0.09 to 0.25 kWh / kg, more preferably of from 0.10 to 0.20 kWh / kg, more preferably of from 0.102 to 0.16 kWh / kg, and most preferably of from 0.107 to 0.140 kWh / kg. Exemplary values for the SME are about 0.124 kWh / kg, about 0.132 kWh / kg, about 0.137 kWh / kg, about 0.121 kWh / kg, about 0.128 kWh / kg, about 0.135 kWh / kg, about 0.112 kWh / kg, about 0.122 kWh / kg, about 0.127 kWh / kg, about 0.110 kWh / kg, about 0.115 kWh / kg, and about 0.119 kWh / kg. Other useful values for the SME are about 0.239 kWh / kg, about 0.265 kWh / kg, and about 0.174 kWh / kg.

[0077] Furthermore, the inventors found that exemplary results are obtained if a specific combination of P, T, and SME are used, which are defined as the “degradation factor”. The degradation factor as used herein refers to the parameter SME / (P / T), which can also be written as SME*T / P. The units for the degradation factor are kWh °C bar'1kg'1.

[0078] Preferably, the extrusion process is characterized by a degradation factor in a range of from 0.05 to 10 kWh °C bar'1kg'1, preferably in a range of from 0.20 to 9 kWh °C bar'1kg'1, more preferably in a range of from 0.35 to 8 kWh °C bar'1kg'1, and most preferably in a range of from 0.45 to 7 kWh °C bar'1kg'1; wherein SME (in kWh / kg) is the specific mechanical energy transferred from the extruder to the starting composition; P (in bar) is the pressure at the die of the extruder; and T (in °C) is the melt temperature at the die of the extruder. Exemplary values for the degradation factor are about 0.49, about 0.56, about 0.75, about 0.60, about 0.68, about 0.94, about 1.18, about 1.39, about 1.70, about 1.77, about 1.80, about 1.90, about 2.12, about 2.28, about 2.89, about 6.19, or about 6.57 kWh °C bar'1kg'1. As the skilled person is aware, some parameters, such as the throughput and the screw speed, may depend on the type of extruder and screws used. The skilled person is able to recalculate the values for these parameters for other types of extruder. For example, typically for a small extruder, the extruder can be operated at 100 - 1800 screw rotations per minute (rpm), preferably 200 - 1250 rpm, more preferably 250 - 750 rpm; alternatively, the extruder can preferably be operated at 250 - 1600 rpm. Higher rotation speeds, such as 500 - 1600 rpm, preferably 900 - 1500 rpm, provide for higher throughput and hence improved production efficiency. Likewise, also typical for a small extruder is a throughput of about 1-100 kg / h, or about 10-100 kg / h.

[0079] In a particularly favourable embodiment, the extrusion process is characterized by:

[0080] (i) a temperature in a barrel section of the extruder in a range of from 100 to 250 °C, preferably of from 130 to 225 °C, more preferably of from 140 to 200 °C, most preferably of from 145 to 170 °C;

[0081] (ii) a die pressure (P) in a range of from 10 to 90 bar, preferably of from 25 to 50 bar, more preferably of from 30 to 40 bar; and / or

[0082] (iii) a specific mechanical energy (SME) of at least 0.05 kWh / kg, preferably an SME in a range of from 0.107 to 0.30 kWh / kg, more preferably an SME in a range of from 0.107 to 0.140 kWh / kg.

[0083] In another preferred embodiment, the extrusion process is performed at a temperature in a range of from 110 to 220 °C, a pressure in a range of from 4 to 50 bar, and a torque in a range of from 15 to 65 %; said temperature, pressure and torque collectively providing a specific mechanical energy (SME) in a range of from 0.08 to 0.30 kWh / kg; wherein the moisture content of the composition during the extrusion process is in a range of from 15 to 35 wt.%, relative to the total weight of said composition.

[0084] In an exemplary embodiment, the extruder can be a ZSK 27 extruder (a co-rotating twin-screw extruder marketed by Coperion). In this particular embodiment, further described in the examples, the extruder comprises 6 blocks, having a total length of 24D. The diameter D of the screws is 27 mm. The barrel section, and thus the screws, have a total length of around 648 mm, and the screw diameter is 27 mm. In this exemplary embodiment, the screw configuration comprises two reversed pitch elements alternatingly intertwined with conveying elements. The reversed pitch elements are preferably placed towards the end of the screw starting at position 18 D. The die section comprises two conical cavities, comprising cylindrically shaped die holes having a diameter of 3 mm and a length of 2 mm.

[0085] In this particular embodiment, the temperature in the first (feeding) block and second (water addition) block can be more or less ambient. Preferably, the second block is operated at a temperature of from 20 to 55 °C, preferably of from 35 to 45 °C. The third and fourth blocks are operated at a temperature of 50 - 100 °C, preferably 60 - 90 °C. The fifth and sixth blocks are operated at a temperature of 100 - 250 °C, preferably 130 - 180 °C, more preferably 140 - 160 °C. When using an extruder barrel having six barrel blocks, in particular the exemplary extruder barrel as disclosed herein, it is preferred that:

[0086] (a) the temperature in the second barrel block is in a range of from 30 to 50 °C, more preferably from 35 to 45 °C, more preferably from 37 to 43 °C, and most preferably about 40 °C;

[0087] (b) the temperature in the third barrel block is in a range of from 50 to 70 °C, more preferably from 55 to 65 °C, more preferably from 57 to 63 °C, and most preferably about 60 °C;

[0088] (c) the temperature in the fourth barrel block is in a range of from 80 to 100 °C, more preferably from 85 to 95 °C, more preferably from 87 to 93 °C, and most preferably about 90 °C;

[0089] (d) the temperature in the fifth barrel block is in a range of from 110 to 130 °C, more preferably from 115 to 125 °C, more preferably from 117 to 123 °C, and most preferably about 140 °C; and / or

[0090] (e) the temperature in the sixth barrel block is in a range of from 150 to 170 °C; more preferably of from 155 to 165 °C, more preferably of from 158 to 162 °C, and most preferably about 160 °C.

[0091] Preferably, the throughput is 15 to 45 kg / h, more preferably of from 25 to 35 kg / h, based on total weight (including moisture); and operated at 500 rpm. At higher rotation speed, the throughput can be higher, as the skilled person appreciates. The throughput can be 10 - 100 kg / h, preferably 15 - 80 kg / h. At 800 - 1600 rpm, the throughput can be 40 - 80 kg / h.

[0092] Obtaining the extrudate and further optional steps

[0093] In step (c) of the method of the invention, the extrudate is obtained. It will be understood that the extrudate is the modified starch composition of the invention.

[0094] In principle, the extrudate can be used directly, without any further processing steps.

[0095] However, optionally the extrudate is dried. Suitable drying techniques are known in the art. In particular, the extrudate may be subjected to air drying (in particular hot-air drying), fluidized-bed drying, drum drying, microwave drying, vacuum drying, freeze drying, and / or infrared drying. Preferably, the extrudate is dried to a moisture content of at most 20 wt%, more preferably at most 15 wt%, more preferably at most 10 wt%, more preferably at most 5 wt%, more preferably at most 4 wt%, more preferably at most 3 wt%, more preferably at most 2 wt%, and most preferably at most 1 wt%, wherein the wt% is relative to the total weight of the extrudate.

[0096] Optionally, the extrudate is subjected to particle size reduction. The optional step of reducing the particle size of the extrudate may be performed before, after, and / or during the optional drying of the extrudate. Suitable techniques to reduce the particle size of starch compositions are known to the skilled person. In particular, the extrudate may be subjected to grinding, crushing, milling, sieving, screening, and / or high-shear blending. Preferably, the extrudate is subjected to hammer milling, pin milling, or ball milling; more preferably the extrudate is subjected to hammer milling.

[0097] Preferably, the method of the invention consists of steps (a), (b) and (c). However, in some embodiments, step (c) is followed by one or more subsequent processing step(s) of the extrudate.

[0098] Modified Starch Compositions

[0099] The invention also pertains to a modified starch composition obtainable by a method of the invention. However, all embodiments regarding modified starch compositions obtainable by a method as disclosed herein may also relate to the modified starch composition per se (viz. without reference to the method by which the composition is obtainable).

[0100] Preferably, the modified starch composition comprises starch that has been modified using at least one starch-modifying agent as disclosed herein. It will be understood that the modified starch composition comprises modified starch obtainable by a method of the invention.

[0101] Preferably, the modified starch is selected from the group consisting of crosslinked starch, esterified starch, etherified starch, oxidized starch, hydrolyzed starch, phosphorylated starch, grafted starch, and combinations thereof. In this respect, it will be understood that “combinations thereof’ refers to modified starch having been modified in more than one way, for example crosslinked and phosphorylated starch.

[0102] Most preferably, the modified starch is crosslinked starch. Preferably, the crosslinked starch is crosslinked by one or more crosslinkers selected from the group consisting of citric acid, trimetaphosphate, epichlorohydrin, phosphorus oxychloride (POCk), tripolyphosphate, anhydride, and pyrophosphate; more preferably the one or more crosslinkers are selected from the group consisting of citric acid, and trimetaphosphate. Preferably, the anhydride is adipic anhydride.

[0103] Preferably, the modified starch composition has a viscosity in a range of from 500 to 3000 cP, more preferably from 700 to 2400 cP, more preferably from 720 to 2300 cP, most preferably from 750 to 2250 cP. Exemplary values for the viscosity include about 1295 cP, about 1146 cP, about 888 cP, about 1238 cP, about 786 cP, about 1029 cP, about 1369 cP, about 2235 cP, about 2213 cP, about 1960 cP, about 2121 cP, about 1893 cP, and about 1745 cP. Preferably, the viscosity is the viscosity measured at the end of the procedure described in Example 1.4 or at the end of the procedure described in Example 2.4.

[0104] Preferably, the modified starch composition of the invention comprises modified starch having a viscosity of at most 95% of the viscosity of the native granular starch from which the modified starch was prepared. More preferably, this value is at most 90%, more preferably at most 85%, even more preferably at most 80%, more preferably still at most 75%, and most preferably at most 70%. Preferably, this value is in a range of from 25 to 95%, more preferably of from 35 to 90%, more preferably of from 40 to 85%, more preferably from 45 to 80%, even more preferably of from 50 to 75%, and most preferably of from 55 to 70%.

[0105] Preferably, the modified starch composition of the invention comprises at least 55 wt% of amylopectin, more preferably at least 60 wt%, more preferably at least 65 wt%, and most preferably at least 70 wt%. Preferably, the modified starch composition of the invention comprises amylopectin in an amount in a range of from 55 to 99 wt%, more preferably from 60 to 98 wt%, more preferably from 65 to 97 wt%, and most preferably from 70 to 95 wt%.

[0106] Preferably, the modified starch composition of the invention comprises at most 45 wt% of amylose, more preferably at most 40 wt%, more preferably at most 35 wt%, and most preferably at most 30 wt%. Preferably, the modified starch composition of the invention comprises amylose in an amount in a range of from 1 to 45 wt%, more preferably from 2 to 40 wt%, more preferably from 3 to 35 wt%, and most preferably from 5 to 30 wt%.

[0107] Preferably, the modified starch composition of the invention has a moisture content of at most 30 wt%, more preferably at most 25 wt%, more preferably at most 20 wt%, more preferably at most 15 wt%, more preferably at most 10 wt%, more preferably at most 5 wt%, more preferably at most 4 wt%, more preferably at most 3 wt%, more preferably at most 2 wt%, and most preferably at most 1 wt%, wherein the wt% is relative to the total weight of the modified starch composition of the invention.

[0108] In one embodiment, the modified starch composition comprises at least two mass fractions Mwl and Mw2 of different average molecular weight, in which a) Mw2 < Mwl < MwO, MwO being defined as the average molecular weight of the native granular starch from which the modified starch composition was prepared; b) mass fraction Mwl has an average molecular weight of at most 80 % of MwO; c) the sum of the mass fractions Mwl and Mw2 represents at least 50 wt.% of the total weight of the modified starch composition; and d) the mass ratio between the mass fractions Mwl and Mw2 is in a range of from 1.1 : 1 to 20 : 1.

[0109] MwO as used herein refers to the average molecular weight of the native granular starch from which the modified starch composition was prepared. In the embodiments defined using Mwl and Mw2, it is preferred that the modified starch composition does not comprise crosslinked starch. In that context, it is preferred that in the modified starch composition the modified starch is selected from the group consisting of esterified starch, etherified starch, oxidized starch, hydrolyzed starch, phosphorylated starch, grafted starch, and combinations thereof.

[0110] In one aspect, mass fraction Mwl has an average molecular weight of at most 79%, at most 78%, at most 77%, at most 76%, at most 75%, at most 76%, at most 75%, at most 74%, at most 73%, at most 72%, at most 71%, or at most 70% of MwO.

[0111] In further preferred embodiments, mass fraction Mwl has an average molecular weight of at most 65 % of MwO, more preferably at most 60 %, at most 55 %, at most 50 %, at most 45 %, at most 40 %, at most 39 %, at most 38 %, at most 37 %, at most 36 %, at most 35 %, or at most 34 % of MwO.

[0112] In some embodiments, mass fraction Mwl has an average molecular weight of at least 5 % of MwO, preferably at least 7 %, at least 10 %, at least 12 %, at least 14 %, at least 16 %, at least 18 %, at least 20 %, at least 22 %, at least 24 %, or at least 25 % of MwO. Preferably, mass fraction Mwl has an average molecular weight in a range of from 2 to 80 % of MwO, more preferably of from 3 to 60%, more preferably of from 4 to 45%, and most preferably of from 5 to 35%.

[0113] In a composition of the invention, Mwl is less than MwO, and Mw2 is less than Mwl. Suitably, Mw2 has an average molecular weight of 0.2 - 60 % of MwO, preferably 0.4 to 40% of MwO, more preferably from 0.5 to 15%, even more preferably from 0.6 to 5%, and most preferably of from 0.7 to 2.5% of MwO.

[0114] Alternatively or additionally mass fraction Mw2 has an average molecular weight of at most 20 % of MwO, preferably at most 18 %, at most 16 %, at most 14 %, at most 12 %, at most 11 %, at most 10 %, at most 9 %, at most 8%, or at most 7 %, of Mwl and / or mass fraction Mw2 has an average molecular weight of at least 2 % of Mwl, preferably at least 3 %, at least 4 %, at least 5 %, at least 6 %, at least 7 %, at least 8 %, at least 9 %, at least 10 % of Mwl.

[0115] Preferably, Mw2 has an average molecular weight of 1 - 70 % of Mwl, preferably 2 to 50% of Mwl, more preferably from 3 to 30% of Mwl, even more preferably from 3.5 to 20%, and most preferably from 4.0 to 15% of Mwl.

[0116] As will be understood by a person skilled in the art, the absolute average molecular weight values of the different fractions will depend on the type of granular starch used as starting material. Preferably, the native granular starch from which the modified starch composition was prepared comprises:

[0117] (i) a waxy potato starch, characterized by an MwO of 100 000 kDa ± 10 000 kDa, preferably about 100 223 kDa;

[0118] (ii) a native potato starch, characterized by an MwO of 450 000 kDa ± 45 000 kDa, preferably about 443 847 kDa; and / or

[0119] (iii) a waxy tapioca starch, characterized by an MwO of 270 000 kDa ± 27 000 kDa, preferably about 270 000 kDa.

[0120] In another embodiment, the modified starch composition comprising at least two starch mass fractions Mwl and Mw2 of different average molecular weight, in which a) mass fraction Mwl has an average molecular weight in a range of from 1000 to

[0121] 350 000 kDa; preferably of from 2000 to 300 000 kDa, more preferably of from 3000 to 250 000 kDa, more preferably of from 4000 to 200 000 kDa, more preferably from 5000 to 150 000 kDa, more preferably from 6000 to 125 000 kDa, more preferably from 7000 to 100 000 kDa, more preferably from 8000 to 90 000 kDa, more preferably from 9000 to 80 000 kDa, more preferably from 10 000 to 70 000 kDa, more preferably from 11 000 to 60 000 kDa, more preferably from 12 000 to 50 000 kDa, more preferably from 13 000 to 40 000 kDa, more preferably from 14 000 to 35 000 kDa, more preferably of from 15 000 to 34 000 kDa, more preferably of from 16 000 to 33 000 kDa, and most preferably of from 17 000 to 32 000 kDa; and b) mass fraction Mw2 has an average molecular weight in a range of from of from 100 to 350 000 kDa; preferably of from 200 to 300 000 kDa, more preferably of from 300 to 250 000 kDa, more preferably of from 400 to 200 000 kDa, more preferably from 500 to 150 000 kDa, more preferably from 600 to 125 000 kDa, more preferably from 700 to 100 000 kDa, more preferably from 800 to 50 000 kDa, more preferably from 900 to 40 000 kDa, more preferably from 1000 to 30 000 kDa, more preferably from 1100 to 20 000 kDa, more preferably from 1200 to 10 000 kDa, more preferably from 1300 to 9000 kDa, more preferably from 1400 to 8000 kDa, more preferably of from 1500 to 7000 kDa, more preferably of from 1600 to 6000 kDa, more preferably of from 1700 to 5000 kDa, more preferably of from 1800 to 4000 kDa, more preferably of from 1900 to 3000 kDa, and most preferably of from 2000 to 2500 kDa; and c) the sum of the starch mass fractions Mwl and Mw2 represents at least 50 wt.%, of the total weight of the modified starch composition; and d) the mass ratio between the starch mass fractions Mwl and Mw2 is 1.1 : 1 - 20 : 1.

[0122] In the embodiments defined using Mwl and Mw2, preferably the sum of the starch mass fractions Mwl and Mw2 represents at least 50 wt.%, preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 75 wt%, more preferably at least 80 wt%, more preferably at least 85 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, more preferably at least 97 wt%, and most preferably at least 99 wt%, of the total weight of the modified starch composition.

[0123] In the embodiments defined using Mwl and Mw2, it is preferred that the mass ratio between Mwl and Mw2 is in the range of from 2 : 1 to 20 : 1, 3: 1 to 20: 1, 5: 1 to 20: 1, 6: 1 to 20: 1 or 7: 1 to 20: 1, 3 : 1 to 15 : 1, 4 : 1 to 14: 1, 5: 1 to 13: 1, 4: 1 to 13: 1 or 5: 1 to 11 : 1.

[0124] In some embodiments, the average molecular weight of the modified starch composition of the invention as a whole is at least about 13 500, at least about 14 000, at least about 15 000, at least about 16 000, at least about 17 000, at least about 18 000, at least about 19 000, at least about 20 000, at least about 21 000, at least about 22 000, at least about 23 000, at least about 24 000, at least about 25 000, at least about 26 000, at least about 27 000, at least about 28 000, or at least about 30 000 kDa. In some embodiments, the average molecular weight of the modified starch composition of the invention as a whole is at most about 32 000, at most about 3 1000, at most about 30 000, at most about 29 000, at most about 28 000, at most about 27 000, at most about 26

[0125] 000, at most about 25 000, at most about 24 000, at most about 23 000, at most about 22

[0126] 000, at most about 21 000, at most about 20 000, at most about 19 000, at most about 18

[0127] 000, at most about 17 000, at most about 16 000, or at most about 15 000 kDa.

[0128] Exemplary ranges for the average molecular weight of the modified starch composition of the invention as a whole include of from 13 000 to 34 000 kDa, from 14

[0129] 000 to 32 000 kDa, from 14 000 to 30 000 kDa, from 14 000 to 29 000 kDa, from 15

[0130] 000 to 29 000 kDa, from 16 000 to 28 000 kDa, from 16 000 to 26 000 kDa, from 17

[0131] 000 to 30 000 kDa, from 20 000 to 35 000 kDa, from 13 000 to 20 000 kDa, from 13 000 to 27 000 kDa, from 13 000 to 25 000 kDa, from 17 000 to 27 000, from 17 000 to 26 000, from 18 000 to 25 000 kDa, from 19 000 to 32 000 kDa, from 20 000 to 28 000 kDa, from 2 2000 to 27 000 kDa, from 24 000 to 29 000 kDa, from 25 000 to 30 000 kDa, from 20 000 to 25 000 kDa and from 16 000 to 27 000 kDa.

[0132] In some embodiments, the average poly dispersity of the composition of the invention as a whole is at least about 1.6, at least about 1.7, at least about 1.8, at least about 1.9, at least about 2.0, at least about 2.1, at least about 2.2, at least about 2.3, at least about 2.4, at least about 2.5, at least about 2.6, at least about 2.7, at least about 2.8, at least about 2.9, at least about 3.0, at least about 3.1, at least about 3.2, at least about 3.3, at least about 3.4, at least about 3.5, at least about 3.6, at least about 3.7, at least about 3.8, at least about 3.9, at least about 4.0, at least about 4.1, at least about 4.2, at least about 4.3, at least about 4.4, at least about 4.5, at least about 4.6, or at least about 4.7. In some embodiments, the average poly dispersity of the composition of the invention as a whole is at most about 5.0, at most about 4.9, at most about 4.8, at most about 4.7, at most about 4.6, at most about 4.5, at most about 4.4, at most about 4.5, at most about 4.4, at most about 4.3, at most about 4.2, at most about 4.1, at most about 4.0, at most about 3.9, at most about 3.8, at most about 3.7, at most about 3.6, at most about 3.5, at most about 3.4, at most about 3.3, at most about 3.2, at most about 3.1, or at most about 3.0. In some embodiments, it is preferred that the overall poly dispersity of the modified starch composition is in a range of from 1.6 to 3.0, 2.2 to 4.0, 2.2 to 3.5, 2.0 to 5.0, 2.2 to 4.8, 2.4 to 4.8, 2.8 to 5.0, 3.0 to 4.8, 4.0 to 4.8, or 4.3 to 4.8.

[0133] Further products and applications

[0134] A modified starch composition as provided herein has unique properties that make it suitable for specialized food and non-food applications. Modified starch compositions of the invention have a wide range of applications due to the various possible modifications. Modified starch compositions are particularly useful in food products (instant foods, desserts, sauces), pharmaceuticals (drug delivery, for example capsules), cosmetics (creams, gels), and industrial uses (adhesives, textiles, and packaging). The possible variations in modification allow for flexibility in product formulation, easy processing, and enhanced consumer convenience. The invention therefore also relates to a consumer product or an industrial product comprising a modified starch composition according to the invention. For example, provided herein is a food item, a feed item, a thickening agent, an adhesive, a cosmetic product, paper, or a construction material, comprising a modified starch composition according to the invention. Furthermore, the invention relates to the use of a modified starch composition according to the invention as a food ingredient, a feed ingredient, a thickening agent, and / or an adhesive agent. Also provided is the use of a modified starch composition of the invention as an ingredient for a cosmetic product, a gelling agent, a pectin replacer, a gelatin replacer, as an ingredient for the production of paper, and / or as a component of a construction material.

[0135] In one embodiment, the invention provides the use of a modified starch composition in the food industry, for example in instant or no-cook food items. Also provided is a food item comprising a modified starch composition. For example, it is ideal for applications like instant puddings or desserts, or in cold-prepared salad dressings and dips. Other applications include instant soups and sauces, and bakery fillings and glazes.

[0136] In a specific aspect, the modified starch composition of the invention is used in a confectionery product. Alternatively, modified starch compositions of the invention can improve texture and stability in frozen desserts like ice cream or frozen yogurts by creating a stable, creamy consistency. Still further food applications include meat and fish products. In one embodiment, the invention provides the use of a modified starch composition of the invention as a food ingredient, thickening agent, and / or (vegan) gelatin replacer. Furthermore, modified starch compositions of the invention can be used in dairy products, such as yogurt.

[0137] As there is also a strong desire to provide more plant-based products, especially from an environmental perspective, it is an additional advantage of products of the invention that these can in principle be plant-based (i.e. vegan).

[0138] Also envisaged are pharmaceutical and nutraceutical applications. In one embodiment, a modified starch composition of the invention is used in a drug delivery systems or a topical gel.

[0139] As such, the disclosure also relates to modified starch compositions of the invention for use as a medicament. Furthermore, the disclosure pertains to a method of treating a subject, said method comprising the step of administering a modified starch composition of the invention to said subject. Additionally, the disclosure relates to the use of a modified starch composition of the invention in the manufacture of a medicament for the treatment of a disease in a subject.

[0140] Still further, the composition of the invention finds its use in a nutritional supplement where a thickened gel consistency enhances mouthfeel or helps with ease of ingestion, like instant meal replacements or protein gels. Modified starch compositions of the invention can provide smooth, spreadable textures for skincare products. Other products that can benefit from including a modified starch composition as provided herein include cosmetics and personal care products, such as lotions, creams, hair gels and styling products.

[0141] Modified starch compositions of the invention also have a range of industrial applications. Modified starches can be used in adhesives. These starches can furthermore be used in textile processing, especially in warp sizing (coating of yarns). Modified starch compositions of the invention can improve the strength, flexibility, and resilience of paper products and biodegradable packaging materials, especially those that require moisture resistance. Finally, the modified starch compositions of the invention can also be used in construction.

[0142] Further definitions

[0143] Unless indicated otherwise, “wt%” as used herein refers to the weight percentage as compared to the dry weight of the relevant composition.

[0144] Unless indicated otherwise, “average molecular weight” as used herein refers to the weight average molecular weight.

[0145] Unless indicated otherwise, “extrusion barrel” and “extruder barrel” are herein used interchangeably.

[0146] As used herein, “about” preferably means a deviation of at most 10% of the given value, more preferably at most 7.5%, more preferably at most 5%, even more preferably at most 2.5%, and most preferably at most 1%. EXAMPLES

[0147] The invention is illustrated below using several examples. It will be understood that the invention is not limited thereto, and other embodiments such as those listed above are also capable of achieving the technical effects and benefits of the invention. In particular, the starting materials and extrusion conditions used in the examples are not limiting, and the specification indicates other suitable materials and conditions.

[0148] Example 1 relates to the extrusion of native potato starch in the presence of citric acid, and viscosity analysis of the extrudates.

[0149] Example 2 pertains to the extrusion of native potato starch or native faba starch in the presence of sodium trimetaphosphate (STMP), and viscosity analysis of the extrudates.

[0150] Example 1 - Extrusion of native potato starch in the presence of citric acid

[0151] Example 1.1 - Equipment

[0152] A ZSK27 Coperion twin-screw, co-rotating, self-wiping extruder was used which had three peripherals attached to it: a water pump gravimetric feeder (Feeder 1), a solid material gravimetric feeder (Feeder 2) and a centric pelletizer (1 or 3 blades) provided with a compressed air outlet. The extruder barrel was composed of 6 modular blocks having a total length of 24D (4D x 6). The diameter D of the screws was 27 mm. The screws, had a total length of around 648 mm. The die plate used presented conical cavities that ended into cylindrical die holes having a diameter of 3 mm and a length of 2 mm. The die configurations were indicated as nx(DxL), where n stands for the total number of holes, D stands for the Diameter of the holes and L stands for the Length of the holes. The solids were fed at 2D, the water inlet was placed at 9D. The pelletizer blades distance to the die was set as close to the die holes as possible ( < 1 mm).

[0153] Extrudates were milled to the required particle size with a hammer-mill over selected sieves (1 and 0.5 mm). Detailed information regarding equipment used is available in Table 1 below. Table 1. Equipment used for extrusion and milling in Example 1.

[0154] The screw configuration design used was as described in Table 2 (configuration S.2). In said Table C stands for Conveying, K45 stands for Kneading at 45° stagger angle, P stands for Positively conveying elements, N stands for Negatively conveying elements and all elements were defined with element length over pitch length eL / pL.

[0155] Table 2. Screw configuration design S.2.

[0156] Example 1.2 - Barrel block settings and starting materials

[0157] The temperature (T) profile of the barrel block was set as shown in Table 3 below. The temperature of block 1 (feeding block) was not controlled, and is hence indicated with “NA” in Table 3. Blocks 2 to 6 were controlled via automatic electrical heating and water cooling.

[0158] Table 3. Temperature settings of the barrel blocks as used in Example 1. The materials subjected to extrusion in Example 1 are indicated in Table 4.

[0159] Table 4. Components used in exemplary starting compositions for Example 1. Example 1.3 - Extrusion procedure

[0160] Citric acid (CA) was milled to reduce particle size before blending with NPS (for 1 :30 mm:ss at 3000 rpm, with intervals of 00: 15 mm:ss). Different blends of NPS and milled CA were prepared by physically blending the components in a tumbler mixer for 2 hours (15-20 kg total mass). In each experiment, a blend of NPS and milled CA, and water were fed to the extruder and processed accordingly to the settings available in the following table. In case of the reference examples, only NPS and water were fed to the extruder. The resulting pelletized extrudates (with 1 blade at 1000 rpm) were collected and stored on metal plates to let them cool down and release excess moisture overnight.

[0161] The following day, extrudates were hammer milled in two steps (through 1 mm and 0.5 mm sieves, at 3.5 rotational speed setting). For all trials, screw speed of 500 rpm, throughput of 30 kg / h, S.2 screw configuration of Table 2, and a 2x(3x2) die configuration were used. The conditions per experiment are shown in Table 5.

[0162] Table 5. Concentrations of citric acid and extrusion settings used in Example 1.

[0163] Experiments 8-11 are reference examples without modifying agent.

[0164] Example 1.4 Viscosity analysis

[0165] The viscosity of the extrudates of Example 1.3 was determined with a rapid viscoanalyzer (RVA Super 4 Newport Scientific (serial no. 2041657). First, a solution of the extrudate was prepared using demineralized water at room temperature, wherein the solution had a dry matter content of 16.67 wt% based on the total weight of the solution. Then, the viscosity of the solution was measured using the settings described in Table 6 below. Table 6. Settings for the rapid visco-analyzer analyzing the extrudates of Example 1.3.

[0166] Final viscosities of extrudates 4-20 were obtained, and are presented in Table 7 below. Table 7. Final viscosities measured for the extrudates.

[0167] Example 2 - Extrusion of native potato starch or native faba starch in the presence of sodium trimetaphosphate (STMP)

[0168] Example 2.1 - Equipment

[0169] A Process 11 Hygenic Thermo Fisher twin-screw, co-rotating, self-wiping extruder was used which had three peripherals attached to it: two water pumps and a solid material gravimetric feeder. The extruder barrel was composed of 8 modular blocks having a total length of 40D. The diameter D of the screws was 11 mm. The screws had a total length of around 440 mm. The die plate used presented one conical cavity that ended into a cylindrical die hole having a diameter of 2 mm and a length of 2,5 mm. The die configuration was indicated as nx(DxL), where n stands for the total number of holes, D stands for the Diameter of the holes and L stands for the Length of the holes. The solids were fed at 16D, the water inlet was placed at 21D. Extrudates were milled to a reduced coarse particle size. Detailed information regarding equipment used is available in Table 8 below. Table 8. Equipment used for extrusion and milling in Example 2.

[0170] The screw configuration designs used in Example 2 were as described in Tables 9A and 9B (wherein C stands for Conveying, K45 stands for Kneading at 45° stagger angle, P stands for Positively conveying elements, N stands for Negatively conveying. “Ch. (#)” column refers to the amount of channels present on each element type.

[0171] Table 9 A. Screw configuration design S. 7.

[0172] Table 9B. Screw configuration design S.8.

[0173] Example 2.2 - Barrel block settings and starting materials The temperature (T) profile of the barrel block was set as shown in Table 10 below. The temperature of block 1 (feeding block) was not controlled, and is hence indicated with “NA” in Table 10. Blocks 2 to 8 and the die insert were controlled via automatic electrical heating and water cooling.

[0174] Table 10. Temperature settings of the barrel blocks as used in Example 2.

[0175] The materials subjected to extrusion in Example 2 are indicated in Table 11.

[0176] Table 11. Components used in exemplary starting compositions for Example 2.

[0177] Example 2.3 - Extrusion procedure

[0178] Sodium trimetaphosphate (STMP) solutions were prepared to be used as liquid feed for extrusion trials by stirring on a stirring plate at room temperature. The solutions were prepared immediately before starting extrusion trials. NPS and NFS were fed to the extruder and processed accordingly to the settings available in Table 13. The resulting extrudates were collected and stored on metal plates to let them cool down and release excess moisture overnight. The following day, extrudates were milled to a reduced coarse particle size. Reference sample 21 and sample 22 were based on NFS. Sample 23 and reference sample 24 were based on NPS. The STMP concentration refers to the starch dry matter quantity. Solutions of STMP in water were prepared accordingly. Table 12. Starting materials, concentrations of STMP, and screw configurations used in Example 2. Experiments 21 and 24 are reference examples without modifying agent.

[0179] Table 13. Extrusion settings used in Example 2. Experiments 21 and 24 are reference examples without modifying agent.

[0180] Example 2.4 RVA viscosity analysis of samples 21 (ref.) and 22

[0181] The viscosity of the extrudates of reference sample 21 and sample 22 of Example 2.3 was determined with a rapid visco-analyzer (RVA Super 4 Newport Scientific (serial no. 2041657). First, a solution of the extrudate was prepared using demineralized water at room temperature, wherein the solution had a dry matter content of 14.66 wt% based on the total weight of the solution. Then, the viscosity of the solution was measured using the settings described in Table 14 below.

[0182] For reference sample 21, the viscosity at the end of the procedure described in Table 14 was 2820 mPa.

[0183] For sample 22, the viscosity at the end of the procedure described in Table 14 was 4607 mPa. Table 14. Settings for the rapid visco-analyzer analyzing extrudates 21 (ref.) and 22 of Example 2.3.

[0184] Example 2.5 Rheolab viscosity analysis of samples 23, and 24 (ref.)

[0185] The Rheolab viscosity analyses on the final products of sample 23 and reference sample 24 as obtained in Example 2.3 were performed using the Anton Paar analyzer including spindle ST34-2D / 2V. Aqueous solutions of sample 23 and reference sample 24 were prepared using demineralized water, to obtain a dry matter content of 20 wt% based on the total weight of the solution. The settings used for the Anton Paar analyzer are described in Table 15 below.

[0186] For sample 23, the viscosity at the end of the procedure described in Table 15 was 1105 mPa.

[0187] For reference sample 24, the viscosity at the end of the procedure described in Table 15 was 1649 mPa.

[0188] Table 15. Settings for the Anton Paar analyzer analyzing extrudates 23 and 24 (ref.) of Example 2.3.

Claims

Claims1. A method for providing a modified starch composition, wherein the method comprises the steps of:(a) providing a starting composition of a native granular starch, wherein the starting composition has a moisture content in a range of from 15 to 35 wt.% relative to the total weight of the starting composition, and wherein said native granular starch has not been subjected to any pretreatment; preferably the starting composition is free of any non-starch additives; more preferably the starting composition is free of any additives;(b) subjecting the starting composition to thermomechanical degradation by an extrusion process in an extruder barrel; wherein the extrusion process is performed in the presence of at least one starch-modifying agent to modify the starch in situ, and(c) obtaining and optionally drying the extrudate and / or subjecting the extrudate to a step of particle size reduction.

2. The method according to claim 1, wherein during the extrusion process no substances are introduced to the extruder barrel other than the starting composition, the at least one starch-modifying agent, and optionally water.

3. The method according to any one of the preceding claims, wherein the extrusion process is a single-step extrusion process.

4. The method according to any one of the preceding claims, wherein the extrusion process is characterized by a degradation factor defined as SME*T / P in a range of from 0.05 to 10 kWh °C bar'1kg'1, preferably in a range of from 0.20 to 9 kWh °C bar'1kg'1, more preferably in a range of from 0.35 to 8 kWh °C bar'1kg'1, and most preferably in a range of from 0.45 to 7 kWh °C bar'1kg'1; wherein SME (in kWh / kg) is the specific mechanical energy transferred from the extruder to the starting composition; P (in bar) is the pressure at the die of the extruder; and T (in °C) is the melt temperature at the die of the extruder.

5. The method according to any one of the preceding claims, wherein the at least one starch-modifying agent is selected from the group consisting of crosslinkers, hydrolyzing agents, oxidizing agents, etherification agents, esterification agents, grafting agents, and phosphorylation agents.

6. The method according to any one of the preceding claims, wherein the at least one starch-modifying agent is a crosslinker.

7. The method according to claim 6, wherein the crosslinker is selected from the group consisting of citric acid, a trimetaphosphate salt, epichlorohydrin, phosphorus oxychloride (POCk), a tripolyphosphate salt, an anhydride, a hypochlorite salt, and a pyrophosphate salt; wherein preferably the salts are sodium salts; and preferably the anhydride is adipic anhydride.

8. The method according to any one of the preceding claims, wherein the at least one starch-modifying agent is present during extrusion in an amount in a range of from 0.001 to 15 wt%, preferably of from 0.01 to 5 wt%, more preferably in a range of from 0.10 to 3 wt%, more preferably in a range of from 0.20 to 2 wt%, more preferably in a range of from 0.30 to 1.5 wt%, and most preferably in a range of from 0.40 to 1.20 wt%, wherein the wt% is relative to the weight of the starting composition.

9. The method according to any one of the preceding claims, wherein the native granular starch is a starch selected from the group consisting of waxy starch, amylose starch, and regular starch.

10. The method according to any one of the preceding claims, wherein the native granular starch is selected from the group consisting of com starch, potato starch, tapioca starch, faba starch, pea starch, wheat starch, arrowroot starch, sweet potato starch, yam starch, taro starch, and combinations thereof; wherein preferably the native granular starch is potato starch, corn starch, tapioca starch, or a combination thereof; and most preferably the native granular starch is potato starch.

11. The method according to any one of the preceding claims, wherein the native granular starch is potato starch.

12. The method according to any one of the preceding claims, wherein the extrusion process is characterized by:(i) a temperature in a barrel section of the extruder in a range of from 100 to 250 °C, preferably of from 130 to 225 °C, more preferably of from 140 to 200 °C, most preferably of from 145 to 170 °C;(ii) a die pressure (P) in a range of from 1 to 90 bar, preferably of from 2 to 70 bar, more preferably of from 15 to 40 bar; and / or(iii) a specific mechanical energy (SME) of at least 0.05 kWh / kg, preferably an SME in a range of from 0.08 to 0.30 kWh / kg.

13. The method according to any one of the preceding claims, wherein the extrusion process is performed at a temperature in a range of from 110 to 220 °C, a pressure in a range of from 4 to 50 bar, and a torque in a range of from 15 to 65 %; said temperature, pressure and torque collectively providing a specific mechanical energy (SME) in a range of from 0.08 to 0.30 kWh / kg; wherein the moisture content of the composition during the extrusion process is in a range of from 15 to 35 wt.%, relative to the total weight of said composition.

14. The method according to any one of the preceding claims, wherein said starting composition has a moisture content in a range of from 18 to 30 wt%, preferably of from 19 to 28 wt.%, more preferably of from 20 to 25 wt%, relative to the total weight of the starting composition.

15. A modified starch composition obtainable by the method according to any one of the preceding claims.

16. The modified starch composition according to claim 15, wherein the modified starch is selected from the group consisting of crosslinked starch, esterified starch, etherified starch, oxidized starch, hydrolyzed starch, phosphorylated starch, grafted starch, and combinations thereof.

17. The modified starch composition according to any one of claims 15 to 16, wherein the modified starch is crosslinked starch, preferably the crosslinked starch is crosslinked by one or more crosslinkers selected from the group consisting of citric acid, trimetaphosphate, epichlorohydrin, phosphorus oxychloride (POCh), tripolyphosphate, anhydride, and pyrophosphate; preferably the one or more crosslinkers are selected from the group consisting of citric acid, and trimetaphosphate; and preferably the anhydride is adipic anhydride.

18. A food item, a feed item, a thickening agent, an adhesive agent, a cosmetic product, paper, or a construction material, comprising a modified starch composition according to any one of claims 15 to 17.

19. The use of a modified starch composition according to any one of claims 15 to 17 as a food ingredient, a feed ingredient, a thickening agent, an adhesive agent, an ingredient for a cosmetic product, as an ingredient for the production of paper, and / or as a component of a construction material.

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