Methods for producing inhibited starch

Abstract

1. A method for preparing an inhibited starch, comprising: a) providing a slurry comprising granular starch obtained from a starch-containing feedstock; b) alkalizing the slurry by adding ammonia or by adding one or more compounds capable of releasing or generating ammonia in the slurry; c) adjusting the pH of the slurry to a value above 10.0, preferably up to 12.0; and or wherein steps b) and c) are replaced by directly alkalizing the slurry to a pH between 10.0 and 12.0 and adding chloramine or dichloramine to the slurry and step d) is omitted; or wherein step c) is replaced by adjusting the pH of the slurry to a value between 7.0 and 10.0, and wherein step d) is followed by adjusting the pH of the slurry to a value above 10.0, preferably up to 12.0, as well as the inhibited starch produced by the above method, the use of the inhibited starch as an ingredient in foods, and foods containing the inhibited starch.

Description

[Technical Field]

[0001] The present invention relates to a method for producing an inhibited starch with improved warehouse stability, a starch that has increased viscosity when cooked in hard water compared to when cooked in distilled water, an inhibited starch prepared by the method according to the invention, the use of said inhibited starch in food products, and food products comprising said inhibited starch. [Background technology]

[0002] Starch is an important ingredient in the food industry and is commonly used in industrial food manufacturing processes to thicken foods, maintain texture, and stabilize moisture binding in foods during shelf life. Natural, unmodified starch, known as "native starch," while sometimes used as such, has several drawbacks with respect to maintaining the crisp, heavy texture of industrially processed foods due to the extra energy input from shear and the high heat input required in the process to maintain sufficient microbial hygiene after a full heating cycle of such products. To overcome the negative cohesiveness and stringy texture that follow such processes, it is common to inhibit and delay the swelling of starch granules, thereby maintaining the starch granule structure when fully heated in the process and, consequently, maintaining a crisp, heavy texture after such a heating cycle. This is currently achieved by using reactive chemical crosslinkers that are covalently attached to the starch molecules before use in the food industry. This changes the chemical structure and turns the starch into an additive, which is declared under the terms "modified starch" or "food starch-modified" and the finished food product is given an E number or an INS number.

[0003] In recent years, the attitude of final ready-made food consumers towards additives and E numbers has become increasingly negative, so the food industry wants to switch to using ingredients that do not need to be declared as additives on the packaging of final consumer products, but only as ingredients, and therefore do not need to list E numbers, INS numbers, "modified starch" or "food-grade modified starch" on the final food ingredient declaration, but only "starch" or eventually together with vegetable ingredients such as "corn starch" or "wheat starch" to be listed.

[0004] The primary technological function of starch in food manufacturing is as a thickener, aiming to provide the desired viscosity, texture, and mouthfeel of foods. Texture and viscosity characteristics are established by the hydration of starch granules, which occurs when starch is heated in an aqueous suspension. Granular starch absorbs water when the temperature rises above its gelatinization temperature. This means that the starch granules begin to hydrate and swell, significantly increasing their viscosity. When using native starch, the hydrated and swollen starch granules are fragile. If the temperature is maintained for a long period or increased to a higher temperature, the viscosity reaches the so-called "peak viscosity." Thus, at this point, the granular structure begins to break down and disintegrate, resulting in a significant decrease in viscosity. In addition to the decrease in viscosity, another undesirable consequence is an unpleasant, long, sticky texture. The process of granular structure breakdown is further accelerated when heating is performed in an acidic environment and / or with mechanical shear.

[0005] As a result of the above problems, the most important parameters to control or avoid are high temperature, shear, and acidic conditions. It is desirable to modify the properties of starch so that the viscosity is stable or increases during heating to avoid viscosity loss and granule destruction when processed under high heat, high shear, and / or acidic conditions, and also to maintain the integrity of the starch granules in the hydrated, highly swollen state.

[0006] The desired effect is often referred to as improving the robustness of the starch, such that the starch is more resistant to high temperatures, longer cooking times, high shear forces, and acidic conditions, or a combination of these parameters.

[0007] The most commonly used method to increase the process tolerance on starch is to use a technique known as chemical cross-linking, which utilizes reactive bifunctional reagents that result in chemical modification of the molecular structure of the starch.

[0008] Chemical cross-linking inhibits granule swelling, so that heating in water delays granule swelling after the granules reach the gelatinization point. If the level of cross-linking is too low, continued heating combined with strong mechanical shear forces will cause the starch to go into total or partial solution. Chemical cross-linking prevents granular breakdown under such treatment. Chemical cross-linking is achieved by replacing the hydroxyl groups of starch molecules with bifunctional reagents that create covalent bonds between starch molecules. This can be done with specific approved chemicals for making modified food starch additives, such as phosphorus oxychloride, STMP (sodium trimetaphosphate), adipic-acetic mixed anhydride, and epichlorohydrin (which is no longer used for food purposes but was used in the past). Different approved chemical methods for cross-linking are well documented and are commonly used by the starch industry to inhibit starch granule swelling. In practice, this means that the starch granules are able to maintain their granular integrity when exposed to high temperatures, high shear forces, or high temperatures, with or without shear, as well as acidic environments, by cross-linking the starch granules. The higher the degree of cross-linking, the more robust the starch is to these parameters.

[0009] In fact, by using chemical cross-linking modification techniques, the swelling of the starch granules can be adapted to the application and process in which the starch is used, so that optimal properties in terms of viscosity and texture are obtained from the starch itself.

[0010] There is a strong preference among industry and end consumers for replacing chemically modified starches with non-chemically modified starches, but still behaving as such in terms of granule swelling when heated. This is due to the trend towards using only ingredients and no additives in final food formulations and recipes, and going "natural" with food ingredients.

[0011] Inhibition of starch granules without chemical cross-linking agents has been known for some time and can be achieved by dry heat inhibition under alkaline conditions, known as alkaline dry roasting, similar to the production of British gum. In this method, starch is subjected to high temperatures at an alkaline pH and little moisture, achieved, for example, by the addition of sodium hydroxide, soda, or ammonia. Various levels of inhibition can be achieved by using a pH of 8.0 to 11.0, temperatures of 120 to 160 °C, and reaction times of 2 to 120 hours. This technology is well known and has been disclosed in the literature (Crosslinking of starch by Alkali Roasting, Journal of Applied Polymer Science Vol. 11 PP 1283-1288 (1967); Irvin Martin, National Starch & Chemical Corporation) and in several patents (U.S. Pat. No. 8,268,989 B2; European Pat. No. 0721471; European Pat. No. 10382882; U.S. Pat. No. 3,977,897; U.S. Pat. No. 4,303,451; Japanese Pat. No. 61-254602; U.S. Pat. No. 4,303,452; and U.S. Pat. No. 3,490,917).

[0012] The problem with dry heat inhibition of starch granules is that they undergo side reactions during the inhibition process, giving the starch an undesirable taste and color, i.e., a stamp glue-like taste. Discoloration of dry starch at alkaline pH occurs at temperatures above approximately 130°C. While the temperature can be lowered to avoid side reactions, this increases the reaction time and significantly increases production costs. Furthermore, heat inhibition requires high energy costs because it requires the removal of almost all moisture, a process that absorbs a lot of energy. Furthermore, the need for specialized processing equipment requires high investment costs, and the risk of dust explosions necessitates the use of special security equipment. Dry starch is prone to dust explosions.

[0013] Another variation of the technology described in the above patents, focusing on dry thermal inhibition, is disclosed in WO 2013 / 173161 (and U.S. Patent Application No. 2013 / 0309386 A1), in which alcohol is used to dehydrate starch. The alcohol acts as an inhibitor of starch granule gelatinization during high-heat treatment. The starch / alcohol suspension is then heated under very high pressure to maintain the alcohol in a liquid state above its boiling point. The addition of soda maintains the environment at an alkaline pH. As described in the above patents for dry-heat inhibition, processing temperatures similar to those used for alkaline dry roasting are used. Starch color is improved compared to dry alkaline roasting. Color compounds formed during high-heat treatment are simultaneously inhibited and colored by solvent extraction from the starch using a solvent, i.e., liquid alcohol. However, according to the alcohol patent, flammable solvents are used under high pressure and temperature, increasing the risk of explosion or fire during processing. This process requires the use of very expensive pressure reactors that keep the alcohol in a liquid state at very high temperatures, which makes the process expensive.

[0014] Hypochlorite can be used in native starch extraction to achieve four results: to neutralize excess bisulfite, which is regularly used in the starch extraction process; as an antibacterial agent to control microbial growth during extraction; as an inhibitor of the enzymatic browning reaction; and as a microbial disinfectant for starch, which is often subject to high microbial loads resulting from soil contamination during harvest. To maintain the hygienic level of starch produced, something needs to be added to control the hygienic standards of the starch produced.

[0015] Furthermore, it is known that weak inhibition can be achieved by subjecting starch granules to low concentrations of bleaching agents, i.e., active chlorine oxidizing agents such as hypochlorite, at alkaline pH along with any protein residues remaining in the starch. In some cases, the residual protein remaining in the starch after the extraction process can be used, but generally, starches less pure than commercially available pure starches today, i.e., protein contents greater than 0.4% of the starch dry matter, are required to incorporate sufficient inhibition into the starch granules. This inhibition technique is known and is disclosed in U.S. Pat. No. 2,317,752 and British Patent No. 2,506,695 (also published as U.S. Patent Application Publication No. 2015 / 0239994 A1). However, the latter method for inhibiting starch can only be carried out to a limited extent. When higher levels of oxidizing agents are added to starch, it is oxidized, which in turn causes depolymerization, resulting in a decrease in viscosity and easier breakdown of the granular structure during heating. These patented technologies also have the disadvantage that the inhibition is not stable during storage in warehouses prior to use by food manufacturers, resulting in variable results. Inhibition levels change during such storage periods. Furthermore, the addition of the oxidizing agent hypochlorite to starches with high levels of protein residues can result in unpleasant tastes and pool water odors caused by the formation of by-products such as chloramines and haloalkanes, making the starch unsuitable for use in food products.

[0016] When using purer starch, i.e., containing less than 0.4% residual protein, as disclosed in EP 1664126 B2, inhibition is still achievable, but the level of inhibition is significantly lower than that required during industrial food production due to the scarcity of available nitrogen oxide regulators. Thus, while the lower amount of residual protein gives the starch a superior flavor and taste compared to that obtained according to the above-mentioned patent document when using less pure starch and contacting it with hypochlorite, it does not completely address the need for sufficient starch inhibition. Furthermore, the latter document does not address how to stabilize the inhibition obtained after processing during storage in a warehouse before use in the food industry.

[0017] It is also known that inhibition of granular starch can be achieved by combining the active chlorine oxidizing agent hypochlorite with the amino acid glycine. This process is disclosed in U.S. Patent No. 3,463,668. By adding glycine to pure starch, it is possible to add sufficient nitrogen oxide modifiers to obtain higher levels of inhibition without adding fatty compounds that are susceptible to oxidation, catalyzed by oxidation from hypochlorite, and cause the starch to have an oxidative rancidity odor. However, this method is unstable and therefore produces temporary inhibition that cannot replace chemically crosslinked granular starches used in the food industry. These are stored in warehouses for long or short periods before use in industry. The inhibition is not stable during this storage period. Therefore, the results vary depending on the storage time, leading to variable results when used in the food industry.

[0018] WO 2016 / 133447 A1 discloses a method for stabilizing such proteinaceous / amino acid / peptide nitric oxidation modifiers using hypochlorite as an oxidizing agent to inhibit the swelling of starch granules during long storage periods in warehouses prior to use in the food industry, i.e., to prevent their swelling behavior from changing during various storage times. For example, the procedures described in U.S. Pat. No. 3,463,668, European Patent No. 1,664,126 B2, U.S. Pat. No. 2,317,752, British Patent No. 2,506,695, and U.S. Patent Application No. 2015 / 0239994 A1 achieve various inhibitions during various storage periods. In WO 2016 / 133447 A1, residual proteins in starch and / or added amino acids or other low molecular weight peptides are used in conjunction with low levels of sodium hypochlorite to achieve inhibition. The resulting inhibitor is stabilized for long term storage in warehouses by adding antioxidants to the starch, thus converting the transiently unstable inhibitor into a storage stable one.

[0019] However, relying on the residual protein content of starch or adding exogenous protein materials to starch to achieve an inhibitory response is risky because the starch may be considered an allergen and may need to be labeled as such on the final food product label. Once added, it is difficult to completely wash away such added protein sources to a level where they are no longer considered allergens. Relying on the residual protein level of the starch itself can sometimes result in different inhibition levels, as this level varies from batch to batch in the production of extracted starch. This problem highlights the need to develop a method for inhibiting starch to higher levels for starch granule swelling without the need to add proteinaceous or protein-derived materials as nitrogen oxidation regulators. Such a method should result in inhibited starch with improved properties such as taste, odor, and color, while at the same time being more cost-effective than conventional techniques for producing and overcoming the drawbacks of the aforementioned techniques, without the need to add potentially allergenic protein materials to the suspension. Because proteins, peptides, and amino acids are also expensive materials, the elimination of the need to add these automatically reduces the production costs of such starch types.

[0020] Hypochlorite salts, solutions of such salts, or hypochlorous acid intended to oxidize or bleach starch in aqueous suspensions are used at alkaline pH (i.e., pH above 7.0) to control the risk of forming toxic chlorine gas under acidic conditions. While hypochlorite solutions are alkaline themselves, the alkaline agent used is generally some kind of hydroxide solution. This measure is necessary because using hypochlorite alone as an alkalizing agent after addition lowers the pH. The reason for this drop in pH is that the carboxylic acids produced in starch, which are formed when the starch molecule is oxidized, produce acids, lowering the pH during the reaction.

[0021] Another approach to starch inhibition is disclosed in pending PCT application WO 2019 / 032011. In this patent application, starch is inhibited, for example, by using hypochlorite as an oxidizing agent, and the required alkalinity is achieved by adding ammonia or one or more ammonia-releasing or -generating compounds under slightly alkaline conditions. Advantageous storage stability during storage is achieved by stabilizing the inhibition in a manner similar to WO 2016 / 133447 A1. The pH is maintained within the range in which hypochlorous acid is found in the system, i.e., a pKa constant of approximately 7.5, as calculated from the acid dissociation constant of hypochlorous acid. Therefore, WO 2019 / 032011 states that to achieve starch inhibition, the pH must be between 7.0 and 10.0, i.e., a pH range in which chloramines can be formed from the reaction between ammonia and hypochlorous acid, while at the same time, different haloalkanes can be formed. Because no exogenous proteinaceous material is added, no allergens are added. Highly pure starch can be used, with residual protein content well below 0.4%. Because only easily removable ammonia or ammonia-producing compounds, such as salts, are used as nitrogen oxidation regulators, the addition level can be as high as necessary to achieve the desired inhibition level. These compounds are easily removed during the post-treatment starch washing process. Because no fatty acids are added, this method avoids the off-flavors caused by oxidative rancidity from unsaturated fatty acids, and the starch retains its flavor. However, there is a need for further inhibition of starches for use in food, thereby improving their warehouse stability. Summary of the Invention

[0022] The object of the present invention is to provide an inhibited starch that satisfies the above-mentioned needs, eliminates the disclosed problems, and has the disclosed desired advantageous properties. This object is achieved by the method according to the invention as set forth in claim 1. This object is also achieved by the stabilization of the inhibited starch under long-term storage conditions, its use as an ingredient in food products, and food products comprising said inhibited starch, as set forth in the subsequent independent claims. Particular preferred embodiments are disclosed in the dependent claims.

[0023] In one aspect, the present invention relates to a method for producing an inhibited starch, comprising the steps of: a) providing a slurry comprising granular starch obtained from a starch-containing raw material; b) alkalizing the slurry by adding ammonia or by adding one or more compounds capable of releasing or generating ammonia in the slurry; c) adjusting the pH of the slurry to a value above 10.0, preferably up to 12.0; and d) adding at least one chlorine oxidizer to the slurry for reaction with said ammonia; or wherein steps b) and c) are replaced by directly alkalizing the slurry to a pH between 10.0 and 12.0 and adding chloramine or dichloramine to the slurry, and step d) is omitted; Alternatively, step c) is replaced by adjusting the pH of the slurry to a value between 7.0 and 10.0, and step d) is followed by adjusting the pH of said slurry to a value above 10.0, preferably up to 12.0.

[0024] The method according to the invention can therefore be carried out according to three different alternative embodiments as alternatively set out in claim 1, each of which gives an inhibited starch with a desired further improved warehouse storage stability compared to known inhibited starches.

[0025] In one embodiment, the method also includes adding at least one organic acid, bisulfite, or hydrogen peroxide to the slurry to remove residual oxidizing agent, off-tastes, and / or undesirable odors.

[0026] In one embodiment, the method according to the invention also comprises the step of washing out any remaining undesired components in the starch slurry after the reaction according to claim 1 while maintaining the pH at 10.0 or above, and subsequently neutralizing the pH of the starch, whereby the pH of the starch slurry is lowered to 5-7.

[0027] In another aspect, the present invention relates to starch produced by the method according to the invention, which is distinguished as having an increased viscosity when cooked in hard water compared to when cooked in distilled water.

[0028] In another aspect, the present invention relates to an inhibited starch with improved warehouse stability produced by a method according to the present invention.

[0029] In yet another aspect, the present invention relates to the use of the inhibited starch as an ingredient in a food product.

[0030] A further aspect of the present invention is a food product comprising the inhibited starch described above.

[0031] Thus, in accordance with the present invention, it has surprisingly been found that increased inhibition of granular starch can be achieved by alkaline treatment at a pH above 10.0 using small amounts of ammonia added to or released / generated in the starch slurry as an alkalizing agent in combination with an oxidizing agent, such as hypochlorite, hypochlorous acid, chlorine, etc., dissolved in water, while simultaneously reducing the undesirable formation of carboxylic acids in the starch.

[0032] Thus, the present invention provides a method for increasing inhibition of granular starch using one or more compounds capable of releasing bound ammonia or generating ammonia, alternatively or in combination, via an alkalization step, via deamination of amino acids using enzymes, or by deamidation of amides with strong alkali or strong acid.

[0033] More precisely, the compound or compounds capable of releasing or generating ammonia in said slurry are: i) an ammonium compound, preferably an ammonium salt of an acid, preferably ammonium acetate, ammonium chloride, or ammonium citrate, and a hydroxide compound, preferably an alkali metal or alkaline earth metal hydroxide, which is reacted to release ammonia from the ammonium compound; ii) an enzyme to release ammonia from amino acids already present in the slurry of residual protein from the used starch; iii) an oxidizing agent to release ammonia from the α-amino acids already present in the slurry of residual protein from the used starch, or iv) an amide, and optionally an alkali or acid, to release ammonia from said amide in a slurry.

[0034] Thus, the ammonia required as a reactant in the starch slurry can be provided in several different ways, as disclosed under i)-iv) above. Additionally, amino acids can be added to the slurry separately or via the protein to serve as an ammonia source for reaction with the enzymes in ii) above and the oxidizing agent in iii) above.

[0035] Thus, the present invention has surprisingly discovered that higher levels of starch inhibition can be achieved by combining the above-described ammonia / ammonia-releasing compound system, also disclosed in WO 2019 / 032011, with an active chlorine oxidizer, such as hypochlorite, at a level of alkalinity greater than pH 10.0, i.e., a pH greater than 10.0, where hypochlorous acid resulting from added hypochlorite is substantially absent from the system. At this higher pH, the formation of haloalkanes (e.g., trihalomethanes) and chloramines (e.g., pool water odors) can be avoided, as their formation requires reaction with free hypochlorous acid. The higher pH also hydrolyzes bound chlorine from chlorinated haloalkanes, thereby destroying such compounds as they form. At the same time, a higher level of starch inhibition is produced than that achieved when the pH is in the range of 7.0 to 10.0, as used in WO 2019 / 032011. Pool water odors caused by the reaction to form chloramines are also suppressed, improving the sensory properties of the final starch. Using a higher pH range (above 10.0) and washing the starch at this alkaline pH immediately after the reaction between ammonia / ammonia-releasing or -generating compounds and the oxidizing agent hypochlorite is complete before adding acid to neutralize it eliminates the need to add one or more organic acids, bisulfite, or hydrogen peroxide as reducing agents to remove residual hypochlorite, which acts as a precursor to undesirable side-reaction compounds when the pH is lowered to the range that may form during the neutralization step. Furthermore, any unreacted hypochlorite that may remain after the inhibition reaction is complete is removed by the alkaline wash. Such alkaline washes at a maintained pH level reduce the residual protein content of the starch to the lowest achievable level, thus making the starch more suitable as an allergen-free starch. At the same time, warehouse storage stability is also improved, reaching near-perfect stability. Fluctuations during storage are minimal and acceptable.

[0036] The resulting inhibited starch can also be treated with a stabilizing antioxidant before final consumption by the food industry, as in WO 2019 / 032011. We disclose a method for producing a starch that is stable during storage before industrial use, treated with hypochlorite and a nitrogen oxide regulator, i.e., ammonia / ammonia-releasing or -producing compounds. However, this is not always necessary, as high alkalinity during processing tends to result in more stable inhibition with little change during storage, eliminating the need for an additional stabilization step using antioxidants. [Brief explanation of the drawings]

[0037] [Figure 1] 1 shows an acid / base ratio diagram in which % free hypochlorous acid of the total amount added is plotted against pH value for both the pH range representing the method disclosed in WO 2019 / 032011 and the pH range representing the method according to the present invention using a zoomed-in y-axis setting. [Figure 2] 1 shows a diagram illustrating the degree of dissociation of the acid / base forms of two reactants, where the proportion of the undissociated form of the substance in question is plotted against pH value in both a pH range representing the method disclosed in WO 2019 / 032011 and a pH range representing the method according to the present invention using the usual x- and y-axis settings. [Figure 3] Figure 1 shows the difference in starch oxidation in Examples 1a) to 1d), where the viscosity of the resulting starch products is plotted against time along with the temperature gradient during the run. [Figure 4] 1 shows the difference in starch oxidation in Examples 1c), 1d), and 2 at neutral pH, where the viscosity of the resulting starch products is plotted against time along with the temperature gradient during the run. [Figure 5] 1 shows the difference in starch oxidation in Examples 1 c), 1 d), and 2 at pH 3.0, where the viscosity of the resulting starch products is plotted against time along with the temperature gradient during the run. [Figure 6]1 shows the results of a stability test, where viscosity is plotted against time for starch products with a running temperature gradient, where the starch products are either freshly manufactured or stored for two months, where the starch slurry has previously been adjusted to a neutral pH value. [Figure 7] 1 shows the results of a stability test, where viscosity is plotted against time for starch products with a running temperature gradient, where the starch products are either freshly manufactured or stored for two months, and where the starch slurry has previously been adjusted to a pH value of 3. [Figure 8] Figure 1 shows the viscosity plotted against temperature together with the temperature gradient during the run of the product obtained in Example 1 d) at either 15 or 30°C at neutral pH values. [Figure 9] The results are shown for varying the molar ratio of active chlorine (in the form of hypochlorite) to ammonia during a reaction at pH 11.5. The ammonia addition level was held constant; only the active chlorine addition level was varied to achieve different molar ratios. Viscosity is plotted versus time for the starch product, along with the temperature gradient during the Brabender run. The starch slurry was previously adjusted to a neutral pH. [Figure 10] The results are shown for varying the molar ratio of active chlorine (in the form of hypochlorite) to ammonia during a reaction at pH 11.5. The ammonia addition level was held constant; only the active chlorine addition level was varied to obtain different molar ratios. Viscosity is plotted versus time for the starch product, along with the temperature gradient during the Brabender run. The starch slurry was previously adjusted to a pH of 3. [Figure 11] The results are shown for varying the molar ratio of active chlorine (in the form of hypochlorite) to ammonia during a reaction at pH 11.5. The ammonia addition level was varied while the active chlorine addition level was held constant to obtain various molar ratios. Viscosity was plotted versus time for the starch product, along with the temperature gradient during the Brabender run. The starch slurry was previously adjusted to a neutral pH. [Figure 12]The results are shown for varying the molar ratio of active chlorine (in the form of hypochlorite) to ammonia during a reaction at pH 11.5. The ammonia addition level is varied while the active chlorine addition level is held constant to obtain various molar ratios. Viscosity is plotted versus time for the starch product, along with the temperature gradient during the Brabender run. The starch slurry was previously adjusted to a pH of 3. DETAILED DESCRIPTION OF THE INVENTION

[0038] Detailed Description of the Invention and Its Preferred Embodiments First, some formulas present in the patent application text are defined below.

[0039] The expression "starch inhibition" as used throughout the application text is intended to mean the inhibition of swelling of starch granules when heated in water after the starch granules have reached their gelatinization point.

[0040] The expression "native starch" as used throughout the application text is intended to mean extracted and purified starch, i.e., having a residual protein content of at most 0.4% of DM starch, preferably lower than this value, and whose naturally occurring properties have not been chemically or physically modified, so that the starch is still in its native state and has unchanged properties, just as it is in the plant from which it was extracted. The term native starch is well known to those skilled in the art.

[0041] The expression "warehouse stable" as used throughout the application text is intended to mean that such inhibited starches maintain their inhibition level during storage under conditions typical of warehouses and transportation before the starch is used in the food industry to manufacture food products, thereby having the same starch granule swelling properties as freshly made.

[0042] The phrase "calculated as active chlorine" used throughout the application text refers to the amount of chlorine bound in its active oxidation state, e.g., bound to sodium hypochlorite and hypochlorous acid (ClO- ) ion form.

[0043] The term "DM" as used throughout the application is intended to mean "dry matter." This is a measure of total solids obtained by evaporating a solution to dryness under vacuum or drying to constant weight in a drying oven at 135°C. DM is sometimes referred to as "total solids by drying" or "dry solids." Alternative terms of equivalent meaning are "dry substance" and "dry weight."

[0044] As used throughout the application text, the expressions "including active chlorine (x g / l)" and "% w / w active chlorine of DM starch" are intended to mean the amount of active chlorine bound and added as an active oxidizing agent, such as sodium hypochlorite (NaClO), expressed in grams per liter and weight percent per gram of DM starch.

[0045] The expression "% w / w DM starch" as used throughout the application text is intended to mean the percentage of a defined substance calculated as grams per gram of DM starch.

[0046] The expression "350 cmg torsion spring" used in the examples of the present application text is intended to refer to the setting of a Brabender Amyloviscograph torsion spring when evaluating the viscosity profile of such starch pastes. Different torsion springs respond differently depending on the sensitivity of the spring load. Therefore, to understand the viscosity response level and be able to compare different Brabender curves, it is necessary to define the torsion spring being used. The expression and meaning of "torsion spring cmg" is well known to those skilled in the art and is commonly used in measuring starch pastes.

[0047] The term "alkalinization" refers to a pH above 10.0, below the point at which starch undergoes alkaline peptization, the starch granules lose their granular character, and become cold-soluble in water, typically starting at a pH above 12.0 at room temperature in the absence of added gelatinization inhibitors such as sodium sulfate. Thus, in the method according to the invention, a pH of up to 12.0 can be used during alkalinization and still obtain satisfactory starch inhibition results.

[0048] The term "slightly alkalizing" means that the pH is adjusted to a range of 7.0 to 10.0, i.e., slightly above the neutral pH of 7.0.

[0049] The starch to be inhibited may be a native granular starch or a modified starch. In one embodiment, modified starch is provided in the slurry used in the first step a) of the process of the present invention. In another embodiment, the starch is modified after being inhibited.

[0050] The native or modified starches inhibited by the methods of the present invention can be extracted from any of a variety of starch-containing sources, such as potato, maize (corn), tapioca (cassava or manoik), barley, rice, wheat, rye, oats, amaranth, quinoa, sago, beans, peas, starch-containing algae including different varieties, waxy potato, waxy maize (corn), waxy tapioca, waxy barley, waxy rice, waxy sorghum, waxy wheat, waxy beans, and high amylose starches.

[0051] In the starch production process, starch is first extracted from raw materials, purified, and dried to a powder, so-called native starch. Starch from any type of raw material, such as those listed above, can be used in food applications either in its native state or further processed by various techniques to impart desired properties. The production of native starch from different sources, methods for processing native starch, and its associated properties are well known in the art. The starch used to undergo inhibition in the method of the present invention can be produced directly from the starch extraction slurry before it is dried, or alternatively, it can be dried to a powder after inhibition treatment as described herein.

[0052] In one embodiment of the method according to the present invention, waxy starch, i.e., amylopectin-rich starch with an amylopectin content of more than 90% of the starch DM, is used. Amylopectin-rich starches are considered more stable and do not require stabilization by chemical monosubstitutions such as acetylation, monophosphorylation, hydroxypropylation, or 2-octenylsuccinylation to prevent retrogradation from aqueous solutions. It is well known that so-called waxy starches have better stability than starches with a high amylose content (non-waxy starches) with respect to the stability of hydrated starch pastes achieved by gelatinization in water. Stability is also superior for waxy starches with respect to freeze-thaw stability. Therefore, by combining the present invention with waxy starches, i.e., waxy corn, waxy tapioca, waxy barley, waxy potato, waxy wheat, etc., it is possible to achieve starch products with properties equivalent to those of chemically modified amylose-containing starches. In this regard, it has been described that it is possible to create starch products that can compete with chemically modified cross-linked and stabilized starches, i.e., acetylated, monophosphated, or hydroxypropylated starches made by cross-linking, especially when using naturally freeze-thaw stable starch bases such as glutinous rice, amaranth, waxy barley, waxy tapioca, or other amylopectin starches with short outer chains (chains of less than 12 glucose units) in the amylopectin starch structure. However, stabilization of starches by mono-substitution is different from the stabilization obtained in the present invention. Stabilization of starches by single substitution is performed to improve the solution stability against retrogradation, but not to stabilize granule swelling.

[0053] The method of the present invention alters the granule swelling properties of native starch or optionally chemically modified stabilized monosubstituted starch, i.e., starch containing hydroxypropyl or monophosphate groups obtained without the use of chemical crosslinkers. The acetyl or 2-octenylsuccinyl group substitution reaction must be carried out after inhibition; otherwise, the covalently bonded ester bond to the starch in these types of starch becomes unstable, resulting in hydrolysis. Organic ester bonds are not stable at room temperature and above a pH of about 8.0-8.5. At higher temperatures, a lower pH is required to keep the bonds intact in such esterified starches.

[0054] Treatment by the method according to the invention in combination with a retrogradation-stabilizing monosubstitution reaction involving hydroxypropylation or monophosphorylation is carried out by inhibiting the starch granules by alkalizing the starch suspension with ammonia, as in WO 2019 / 032011, or by adding one or more compounds capable of releasing or generating ammonia, e.g., ammonium compounds such as ammonia salts, and then alkalizing the slurry or suspension with a base such as a hydroxide, e.g., sodium hydroxide or potassium hydroxide, to release the bound ammonia. When the treatment is combined with acetylated or 2-octenylsuccinylated starch, the treatment according to the invention is carried out first, followed by the inhibition reaction, followed by the reaction with the esterification reagent at an appropriate pH value.

[0055] As mentioned above, it was surprisingly discovered that even higher inhibition could be achieved with the same dosage of ammonia and hypochlorite as in WO 2019 / 032011 when the pH exceeded the upper limit of 10.0 during the reaction, even though the pH was outside the range in which hypochlorous acid could react with ammonia. In WO 2019 / 032011, reactive chloramines, i.e., active reactants, can be formed within the reaction chamber. After the reaction is complete, one or more wash steps can be performed directly at a higher pH, removing all unreacted hypochlorite ions before the pH is neutralized, thereby achieving the range in which free hypochlorous acid is formed from hypochlorite ions. Therefore, as previously mentioned, it is not necessary to add organic acids, such as ascorbic acid, bisulfite, or hydrogen peroxide, to destroy active chlorine. When the pH reaches the 7.0-10.0 range during the neutralization step, no hypochlorite ions remain, and chloramines and haloalkanes are not produced. Therefore, they do not impart a foul odor or unpleasant taste to the final product. Therefore, the starch has fewer added chemicals and an improved flavor profile.

[0056] In one embodiment of the present invention, inhibited starch is obtained by using native starch that has been extracted and purified to a residual protein level of less than 0.4% w / w, where the starch is considered protein-free. This is the same method as most commercial starches are produced today. Furthermore, the starch may be less pure because proteins are removed in an alkaline washing step after the reaction is complete. The native starch is further mixed with water to obtain a starch slurry with a concentration of 5-45% w / w, more preferably 20-45% w / w, and even more preferably 30-40% w / w. Ammonia, or a compound capable of releasing or generating ammonia, is first added to the slurry. The starch slurry is then heated to 5-70°C, i.e., below the gelatinization temperature of the particular starch used at the ambient pH conditions in the slurry, preferably 10-45°C, more preferably 15-35°C, with continuous stirring to avoid settling of the starch granules and maintain a uniform suspension. Next, the pH is adjusted by adding alkali to a value above 10.0, but up to 12.0, preferably 11.0-11.5. If the amount of ammonia added or produced is not high enough, a stronger alkali, such as an aqueous hydroxide solution, is added to achieve the correct pH in the reaction suspension. By maintaining a pH above 10.0 for the entire reaction cycle after the addition of the oxidizing agent, chloramine formation is kept negligible, thus eliminating the unpleasant pool water odor that might otherwise occur.

[0057] An oxidizing agent, which also functions as a bleaching agent, is added to the starch slurry, followed by stirring. The oxidizing agent is a source of active chlorine, and in one embodiment, is a hypochlorite. In a particularly useful embodiment, the oxidizing agent is sodium hypochlorite, but it may also be another type of alkali metal or alkaline earth metal hypochlorite, such as potassium hypochlorite, calcium hypochlorite, or magnesium hypochlorite. Different types of hypochlorite can be used, but the invention is not limited thereto. Other active chlorine sources can be used individually or as a mixture of various types of oxidizing agents that provide active chlorine. Thus, one or more different oxidizing agents can be added to the starch slurry. An example of such a compound is hypochlorous acid or chlorine gas, which dissolves in water to give hypochlorous acid, which can then be alkalized by the addition of a suitable base.

[0058] In an alternative embodiment of the method of the present invention, chloramine or dichloramine is added directly to the alkalized starch suspension. In this case, ammonia or a compound capable of releasing or generating ammonia is added, and the step of adding an oxidizing agent would not be required. Chloramine is preferred over dichloramine because the latter is a gas at normal operating temperatures. Chloramine is the active reactant formed in WO 2019 / 032011 and results from the in situ reaction of ammonia and hypochlorite. Therefore, instead of adding the two reactants, it can be added directly as a pure reactive compound. In the method of the present invention, the added chloramine or dichloramine is directly hydrolyzed by high alkalinity, and therefore, although it is not an active reactant, inhibition is still obtained, and surprisingly, to a greater extent. Therefore, in this embodiment, the slurry is directly alkalized to a pH between 10.0 and 12.0, followed by the step of adding chloramine or dichloramine to the slurry.

[0059] While the effect of the oxidizing agent during oxidation is not fully understood, it is clear that active chlorine is required to function as an oxidizing agent. Because higher pH levels are outside the range where such reaction products can occur, it is assumed that it somehow interacts with the ammonia source to catalyze internal cross-linking within the starch granules, but that direct chlorination of ammonia is not possible. The assumed theory is that the oxidizing agent in combination with ammonia acts as a catalyst, allowing starch molecules to directly interact and react with each other, potentially forming cross-links via the formation of starch alkoxides, which are more prevalent at higher alkalinity and therefore higher pH values. The amount of oxidizing agent added, calculated as the amount of active chlorine, is 0.03-30% w / w, preferably 0.05-10% w / w, and more preferably 0.1-4% w / w, for sodium hypochlorite as the oxidizing agent. The slurry is then left under agitation to allow the inhibition reaction to occur. This reaction occurs almost instantaneously at temperatures around 30°C. At 15°C, the reaction rate slows down and takes several hours, but still occurs. For practical reasons, it is convenient to allow the reaction to proceed for a time longer than necessary to reach full inhibition levels to ensure consistent batch-to-batch results. Therefore, reaction times are typically between 1 and 1500 minutes, preferably between 30 and 600 minutes, and more preferably between 30 and 240 minutes. Reaction conditions at pHs above 10.0 and 12.0 are such that the amount of free hypochlorous acid is essentially zero and most ammonia is in its free base form. In the absence of free hypochlorous acid, reaction with free ammonia is impossible, and therefore the formation of chloramines or haloalkanes does not occur. If either of these forms, they are automatically hydrolyzed due to the high alkalinity of the reaction. Because ammonia is a volatile gas with a low odor threshold, when dissolved in water to form ammonium hydroxide, the odor is stronger at higher temperatures than at lower temperatures. Therefore, if this odor is a problem, the reaction can be performed at a lower temperature (15°C), where the odor is less pronounced, and the slower reaction rate can be compensated for by extending the reaction time.

[0060] Because the pKa values ​​of hypochlorous acid and ammonium ion are different (7.5 for hypochlorous acid and 9.3 for ammonium ion), different amounts of added chemicals are available to react with each other at different pH values, as calculated from their dissociation in water into their corresponding salt / acid / base forms at different pH values. This means that at pHs above 10.0, virtually no free hypochlorous acid is available, leaving only hypochlorite ions. By maintaining a pH range of 10.0-12.0, the two reactants remain unreactive with each other, unable to react to form chloramines or haloalkanes, only as a result of inhibiting the swelling of starch granules.

[0061] In the present invention, it has also been found that the molar ratio between active chlorine and ammonia source controls the efficiency of inhibition. The optimal inhibition level is in the range of 1 / 4 to 4 / 1 between active chlorine molar concentration and ammonia molar concentration. At 1 / 1, the viscosity is slightly higher than at 2 / 1, but a similar inhibition level is obtained. At a ratio above 4 / 1, the viscosity decreases and the degree of inhibition decreases.

[0062] Figure 1 shows a graph with an expanded y-axis setting, which shows a very low percentage of the remaining free hypochlorous acid in the total added amount relative to the pH in the pH range of the system used, which represents the method of WO 2019 / 032011, and in the pH range representing the method according to the present invention.

[0063] Figure 2 shows both the ammonium ion and hypochlorous acid dissociation systems plotted on the same graph with the usual x- and y-axis settings, with the pH range representing the method according to the present invention compared to the pH range representing the method disclosed in WO 2019 / 032011.

[0064] It is well known to those skilled in the art that hypochlorite treatment of starch will cause starch oxidation.This is because when starch is only in contact with hypochlorite and alkaline hydroxide to obtain an alkaline pH environment, it will cause starch molecule decomposition.This will reduce the molecular weight of starch, resulting in a decrease in viscosity.Oxidation by hypochlorite slightly stabilizes starch against retrogradation from aqueous solution of starch.

[0065] It is important to clarify that the method of the present invention reduces the incorporation of carboxyl groups resulting from starch oxidation, minimizing the consequences associated with the destruction of starch structure. Oxidation using an oxidizing agent such as hypochlorite generates carboxyl groups -COOH within the starch molecule. This is well known, and more specific information can be found in the literature on starch oxidation. Therefore, analysis of the level of carboxyl groups can be used to determine whether a starch product has been oxidized and to define the level of oxidation after such a reaction.

[0066] The method for analyzing the carboxyl content used in connection with the method according to the invention is carried out according to the official method described in the "Purity criteria for modified food starches" found in the FAO / WHO paper or EU legislation, which is carried out as follows:

[0067] The titration is performed in ambient temperature solution instead of hot solution, as used in the official procedure, and using 0.025M NaOH titrant instead of 0.1M NaOH. To obtain greater accuracy, sample preparation is performed on larger amounts of starch sample to avoid loss of starch material during the filtration step in sample preparation of weighed starch for the actual titration. The weighed amount of DM starch for titration is obtained from a larger prepared and dried sample, thus avoiding losses during filtration of the material to be titrated and obtaining greater accuracy from the titration measurement, with the goal of obtaining the true amount of starch content for titration analysis.

[0068] According to international purity standards set by JECFA and EU legislation, the maximum amount of carboxyl groups that can be added to starch and still be classified as bleached starch and therefore not considered oxidized is 0.1% w / w of DM starch. As a result, it is possible to determine whether a starch product has been treated with an oxidizing agent and oxidized, or whether it has only been bleached.

[0069] In accordance with the present invention, it has been shown that when an oxidizing agent is combined with ammonia (in accordance with the method of the present invention), no carboxyl groups are formed in the starch compared to when the starch is oxidized by reacting with the oxidizing agent on its own without the addition of ammonia, thereby demonstrating that no oxidation of the starch molecules has occurred, i.e., less than 0.1% of the carboxyl groups of the added DM starch are added, a level similar to that found in native starch before treatment.

[0070] [Table 1]

[0071] The amount of carboxyl groups obtained from the various experiments in the examples for the native waxy corn used is shown in Table 1 above. The amount of carboxyl groups naturally present in the native starch used is 0.011% w / w. The amount of carboxyl groups added to the starch by treatment with only 0.70% w / w active chlorine added from hypochlorite (Example 1a) is higher than when the same native starch is treated with 0.70% w / w active chlorine and 0.13% w / w ammonia (Example 1c), with a molar ratio of active chlorine to ammonia of 1.1 / 1 at pH 9.0 (0.071% instead of 0.015% w / w). Table 1 also shows the same treatment level at a higher pH of 11.5 in this application at a value of 0.010% w / w (Example 1d), and only hypochlorite added at a higher pH of 11.5, giving a value of 0.041% (Example 1b). Therefore, the increase in carboxyl groups when combining ammonia and hypochlorite is lower than that obtained when the same amount of hypochlorite is used alone without adding ammonia. When combined with ammonia, no additional oxidation occurs at high alkalinity during the reaction. It is clear that combining active chlorine with ammonia avoids oxidation of starch molecules, but instead inhibits the swelling of starch granules in water during the heating cycle. As the molar ratio of active chlorine to ammonia increases, a slight increase in carboxyl group formation is obtained due to more available hypochlorite acting on the starch. However, when the ratio between active chlorine and ammonia is kept in the molar range below 4 / 1, the increase in the amount of carboxyl groups introduced into the starch is kept below the level that would classify it as oxidized starch.

[0072] Once the inhibition reaction is complete, the starch suspension is washed with pure tap water immediately after the treatment time at the alkaline high pH used, i.e., the pH at which the reaction occurred. To ensure all residual chemicals are washed away before pH neutralization, the starch is subjected to a KI test to verify that hypochlorite ions are properly washed away and that no residual active chlorine remains. This eliminates the need for additional active chlorine-destroying chemicals, such as organic acids, bisulfites, or hydrogen peroxide. However, optional addition of organic acids, such as ascorbic acid, erythorbic acid, citric acid, adipic acid, lactic acid, or succinic acid, as well as their salt forms; hydrogen peroxide; or bisulfites, such as bisulfite salts, is possible but generally not required. The alkaline wash before pH neutralization yields a clean, neutral-tasting starch powder after acid neutralization, dehydration, and washing.

[0073] Therefore, unless the pH neutralization step is initiated without an alkaline wash step, it is possible, but not considered necessary, to add an organic acid to act as a chlorine neutralizer (reducing agent) before washing and dehydrating the starch to remove active chlorine residues. Otherwise, such residues would impart the starch product with the unpleasant off-taste or odor of pool water, i.e., chlorinated water, which is common with hypochlorite-treated starches. The type of organic acid can be selected from any of the organic acids listed above, typically used in food applications. However, acids with the ability to act as both reducing and oxidizing agents in different environments, such as ascorbic acid or erythorbic acid, which has previously been used to reduce chloramine formation in drinking water after treatment with sodium hypochlorite or chlorine gas, are preferred. As noted above, if an alkaline wash step is not performed, it is also possible to destroy active chlorine using hydrogen peroxide and bisulfite.

[0074] The organic acids can be added separately or in combination of two or more of them. The amount of organic acid added is 0.001-5% w / w of the DM starch, preferably 0.01-3% 10% w / w of the DM starch, and more preferably 0.05-1% w / w of the DM starch. The same applies to bisulfite and hydrogen peroxide. The slurry is left stirring for, for example, 15-60 minutes.

[0075] Methods for eliminating the taste and odor problems of the optional chlorine used above, including the addition of bisulfite or hydrogen peroxide, are well-known procedures used to destroy excess hypochlorite ions or chlorine gas so that they no longer have oxidizing properties. However, the use of bisulfite may be undesirable because it is considered a strong allergen under international food legislation. Residual levels in starch above 10 ppm must be labeled as an allergen when used in food. Hydrogen peroxide is used to destroy active chlorine at pH levels above 8.5. Below pH 7.0, it no longer acts as such but instead acts as an oxidizing agent, increasing the oxidation of starch molecules.

[0076] The inhibited starch produced according to the method of the present invention is almost completely warehouse-stable, exhibiting only minor viscosity changes during storage. This differs from the results of previously described starch granule inhibition reactions using nitrogen oxidation regulators, as described in U.S. Patent No. 3,463,668, European Patent No. 1664126 B2, U.S. Patent No. 2,317,752, British Patent No. 2506695, and U.S. Patent Application Publication No. 2015 / 0239994 A1. The inhibition disclosed in these patent documents decays fairly rapidly with such techniques, and after several weeks of storage in a warehouse under normal conditions, the inhibition was found to be significantly lower than that obtained when the starch was freshly made. Methods for stabilizing such inhibited starches with antioxidants during storage are described in WO 2016 / 133447 A1 and WO 2019 / 032011. While such steps can be implemented in the method of the present invention, they are not required.

[0077] The temperature at which the inhibition reaction occurs is non-thermal. This means that the reaction is carried out at a temperature not high enough to produce a water-free starch. Therefore, the temperature is kept below 100°C, e.g., between 5 and 70°C. Such inhibition is possible with a slurry, as opposed to dry-heat inhibition processes, in which the inhibition is carried out in a near-moisture-free state of starch with an alkaline substance, as described in WO 2013 / 173161 A1; U.S. Pat. No. 8,268,989 B2; EP 0721471; EP 10382882; U.S. Pat. No. 3,977,897; U.S. Pat. No. 4,303,451; JP 61-254602; U.S. Pat. No. 4,303,452; and U.S. Pat. No. 3,490,917. The stabilized inhibited starch produced by the described slurry treatment process can be further modified by any known modification method used in the chemical modification of starch, for example, approved food additive chemical modifications such as acetylation, hydroxypropylation, chemical cross-linking, OSA (octenyl succinic anhydride) modification, and / or physical modifications such as enzyme treatment, dextrinization, gelatinization to render the starch cold water soluble, post-inhibition gelatinization to render the starch cold water swellable, and combinations of two or more thereof. It can then be recovered and added as an ingredient in food production. Alternatively, the stabilized inhibited starch can be recovered from the slurry by further washing and drying, and then added as an ingredient in producing a food product.

[0078] Examples of foods in which the inhibited starches can be used include various types of sauces, soups, dairy products such as fermented crème fraîche and yogurt; batters and breadings; dairy and / or fruit preparations for baked products, such as bake-stable fruit preparations; and milk-based desserts such as puddings, vanilla sauces, ice cream, and mousses.

[0079] Surprisingly, further inhibition is obtained when the process of the present invention is carried out by adjusting the pH of the slurry to a value between 7.0 and 10.0 after the step of adding ammonia or an ammonia-producing or -releasing compound, followed by a step of adding an oxidizing agent as in WO 2019 / 032011, and then further adjusting the pH to a value of about 10.0 or higher, preferably up to 12.0, and more preferably to a value between 11.0 and 11.5 after the reaction has finished at this pH. After such alkaline treatment, a more inhibited starch is obtained, equivalent to the inhibition level obtained by direct treatment at a pH above 10.0. This differs from the theory in WO 2019 / 032011 that the pH must be maintained in the region where chloramines are likely to form, i.e., between 7 and 10.0. The effect of further increasing the inhibition level after the reactants have been consumed simply by raising the pH above the level at which the reaction occurred, resulting in an unexpected further increase in the inhibition level, is surprising and previously unanticipated. This two-stage pH treatment constitutes an alternative embodiment of the process of the present invention. [Example]

[0080] Example 1 Examples 1a) and 1b) demonstrate the effect of hypochlorite treatment on starch alone at pH 9.0 and pH 11.5, without the oxidation regulator / inhibitor ammonia. Example 1c) demonstrates how starch produced in accordance with WO 2019 / 032011 maintains resistance to oxidation with the addition of ammonia, while simultaneously achieving inhibition of granular starch using the same active chlorine level from sodium hypochlorite as in Example 1a). Example 1d) demonstrates the effectiveness of the present invention in achieving higher inhibition levels without oxidation of the starch molecules by using the same amounts of sodium hypochlorite and ammonia at a higher pH of 11.5. The granular starch raw material is waxy maize starch with a residual protein content of less than 0.4%, as analyzed by the Kjeldahl method and calculated with a protein conversion factor of 6.25.

[0081] 1a) 0.70% active chlorine at pH 9.0 In a reaction vessel, 869.1 g of DM waxy maize starch (1 kg by weight) was mixed with 1600 g of cold tap water. The pH was adjusted to 9.0 with dilute aqueous sodium hydroxide solution at a concentration of 3% w / w. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm) was added. 3 56.9 ml of sodium hypochlorite solution containing 100% DM starch was slowly added during stirring to bring the pH as close to 9.0 as possible. Necessary pH adjustments were made by adding sulfuric acid or NaOH solution during the hypochlorite addition. The hypochlorite solution added contained a total of 6.1 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine of the DM starch. After all the hypochlorite was added, the vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C. The starch was directly dehydrated in a vacuum filter and thoroughly washed with fresh tap water. The starch filter cake was resuspended in fresh tap water, and the removal of all hypochlorite during the reaction was confirmed using a KI test. The starch was then neutralized to pH 6.0 with sulfuric acid. The starch was further dehydrated and dried to a powder with a moisture content of less than 15%. 1b) 0.70% active chlorine at pH 11.5 In a reaction vessel, 869.1 g of DM waxy maize starch (1 kg by weight) was mixed with 1600 g of cold tap water. The pH was adjusted to 11.5 with dilute aqueous sodium hydroxide solution at a concentration of 3% w / w. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm) was added. 356.9 ml of sodium hypochlorite solution containing 10% DM starch was slowly added during stirring to bring the pH as close to 11.5 as possible. Necessary pH adjustments were made by adding sulfuric acid or NaOH solution during the hypochlorite addition. The hypochlorite solution added contained a total of 6.1 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine of the DM starch. After all the hypochlorite was added, the vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C. The starch was directly dehydrated in a vacuum filter and thoroughly washed with fresh tap water. The starch filter cake was resuspended in fresh tap water, and the removal of all hypochlorite during the reaction was confirmed using a KI test. The starch was then neutralized to pH 6.0 with sulfuric acid. The starch was further dehydrated and dried to a powder with a moisture content of less than 15%.

[0082] Examples 1a) and 1b) show that starch oxidation is obtained at both pH values ​​when only hypochlorite is added during the reaction. This generates carboxyl groups, resulting in specific oxidation of the starch, as shown in Table 1 and Figure 3. Starch oxidation is visible in the Brabender profile in Figure 3 as a decrease in viscosity response. If the viscosity of the starch drops dramatically during the heating cycle after reaching peak viscosity, this is because the swollen starch granules disintegrate, crumble, and dissolve in water.

[0083] 1c) In the tests carried out, as illustrated in Example 3b) of WO 2019 / 032011, 0.70% active chlorine in DM starch and ammonia (0.13% nitrogen / DM starch) were used in a molar ratio of active chlorine to ammonia of 2.1 / 1. This test illustrates that no oxidation of starch is achieved and, at the same time, that a certain level of inhibition is obtained when using a combination of hypochlorite and ammonia in slightly alkaline conditions, as described in WO 2019 / 032011 and as can be seen in Table 1 and Figure 3.

[0084] In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 4.3 g of NH4Cl was added and dissolved. The pH was then adjusted to 9.0 with 3% aqueous sodium hydroxide. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added.3 56.9 ml of sodium hypochlorite containing 10% DM starch was added while stirring. The hypochlorite solution added contained a total of 6.1 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine of the DM starch. The vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C. 2.6 g of an antioxidant, i.e., ascorbic acid, was added while stirring. The starch slurry was left stirring for 30 minutes, then dehydrated to 55% DM and further washed with fresh tap water. It was then remixed with 890 g of fresh tap water. 10.4 g of citric acid was added while stirring. The starch slurry was left stirring for 30 minutes, and the pH was further adjusted to 6.0 with sodium hydroxide. The starch was further dehydrated and dried to a powder with a moisture content of less than 15%.

[0085] 1d) 0.70% active chlorine and ammonia in DM starch at pH 11.5 (0.13% nitrogen / DM starch) with a molar ratio of active chlorine to ammonia of 2.1 / 1 This test demonstrates that starch oxidation is not achieved and that high inhibition levels are achieved when hypochlorite and ammonia are used at alkaline conditions greater than 7.0-10.0. This results in higher inhibition levels after treatment at a higher pH of 11.5, as seen in Table 1 and Figure 3. Here, the products obtained from Examples 1a), 1b), 1c), and 1d) are evaluated using a Brabender Amyloviscograph Model E run at 75 rpm and a 5% w / w dry solids level using distilled water and a 350 cmg torsion spring. Evaluation was performed at neutral pH, and the results are shown in the profile overlay in Figure 3.

[0086] In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 4.3 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with 3% aqueous sodium hydroxide solution. The temperature was adjusted to 30°C. Active chlorine (107 g / L; density: 1.19 g / cm3) was added. 356.9 ml of sodium hypochlorite containing 10% DM starch was added during stirring. The added amount of hypochlorite solution contained a total of 6.1 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine of DM starch. The vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C. 2.6 g of an antioxidant, i.e., ascorbic acid, was then added. The antioxidant was added for the purpose of comparing the effect of pH value between the present invention and the invention disclosed in WO 2019 / 032011 under similar conditions, as well as for the purpose of the taste test in Example 5. The starch slurry was left stirring for 30 minutes and then remixed with 890 g of fresh tap water. 10.4 g of citric acid was added during stirring. The starch slurry was dewatered to 55% DM and further washed with fresh tap water. The starch slurry was left stirring for 30 minutes and the pH was further adjusted to 6.0 with sodium hydroxide. The starch was further dehydrated and dried to a powder with a moisture content of less than 15%.

[0087] The results are shown in Table 1 and Figure 3. Figure 3 shows that no starch oxidation is achieved when starch is treated with ammonia or hypochlorite in combination with an ammonia-releasing compound. Even though hypochlorite reacts, the level of carboxyl groups added when the ammonia compound is added is the same as that of native starch. In Figure 3, starch granule inhibition is seen as a small viscosity drop after reaching peak viscosity in Example 1c at pH 9, while the viscosity after the cooling cycle is significantly higher. Adding hydroxyl ions before hypochlorite treatment further increases the inhibition achieved, with pH values ​​above 10.0. In Example 1d at pH 11.5, the granules maintain their integrity, resulting in no peak viscosity. This indicates that higher inhibition levels can be achieved by combining ammonia with active chlorine at higher hydroxide ion levels, i.e., higher pH, than previously known. This will result in a greater increase in inhibition of starch granule swelling compared to low levels of hydroxide ions, as described in WO 2019 / 032011.

[0088] Example 2 This example illustrates one alternative to the method of the present invention. It is possible to initially treat the reaction at pH 9.0, i.e., between pH 7.0 and 10.0, with added ammonia and oxidizing agent. After this treatment, once all the hypochlorous acid oxidizing agent has been consumed, the pH can be further increased by adding alkali to obtain a pH of 10.0 to 12.0, and the slurry can be maintained at that pH for a period of time. This will result in a similar, higher level of inhibition as if the reaction had been run directly from the start at the higher pH.

[0089] After the reaction carried out in Example 1c), at 30°C and pH 9.0, additional alkali was added using a 3% w / v NaOH solution to obtain a pH of 11.5. The temperature was maintained at 28°C for an additional 120 minutes. After this step, the starch was dehydrated directly in a vacuum Buchner funnel and washed clean with fresh tap water from any remaining hypochlorite solution, as confirmed by a KI test on a small sample from the wet starch cake. Once the starch filter cake was clean, it was suspended in fresh tap water and neutralized using sulfuric acid solution. After this, it was dehydrated again in a vacuum Buchner funnel, and the neutralization salts were washed off with fresh tap water. The starch was then dried to a moisture level of less than 15%.

[0090] The products from Examples 1c), 1d), and 2 were evaluated using a Brabender Amyloviscograph Model E run at 75 rpm and a 5% w / w dry solids level, using distilled water and a 350 cmg torsion spring. Evaluations were conducted at both neutral and acidic pH 3.0, with the results shown in the overlay profiles in Figure 4 (neutral pH) and Figure 5 (pH 3.0). Figure 4 shows that the product using pH 9.0 gave the lowest degree of inhibition of the three runs. As previously noted, higher levels of inhibition were obtained when the reaction was conducted at pH 11.5 rather than pH 9.0. Combining the treatments by first conducting the reaction at pH 9.0 and then raising the pH to 11.5 resulted in a steeper slope, as with the direct reaction at pH 11.5. However, Example 2 yielded a slightly higher level of inhibition due to slightly less granule swelling than Example 1d). Figure 5 shows the same results, but instead uses pH 3.0 in the test. Lowering the pH during starch cooking is a way to accelerate starch granule swelling when complete granule swelling is not achieved at neutral pH. The increased inhibition is seen in Figure 5 in that the temperature at which the starch reaches full peak viscosity is higher at pH 11.5 than at pH 9.0, with the dual-treated product from Example 2 having the highest temperature at which complete swelling is achieved. It is also more stable to acid hydrolysis because its viscosity is better maintained than the material at pH 9.0. This also indicates a higher degree of inhibition of starch granule swelling.

[0091] Example 3 This example shows that the starch is almost completely stable and shows only minor viscosity changes during warehousing without the addition of extra antioxidants.

[0092] The molar ratio of active chlorine to ammonia is 2.1 / 1, 0.70% active chlorine + 4.3g NH 4 Cl (0.13% nitrogen / DM starch) In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. While stirring, 4.3 g of NH4Cl was added. The pH was adjusted to 11.5 with 3% w / v sodium hydroxide solution. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added. 3 56.9 ml of sodium hypochlorite containing 10% DM starch was added during stirring. The hypochlorite solution added contained a total of 6.1 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine of the DM starch. The vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C. The starch slurry was dewatered to 55% DM and further washed with fresh tap water until a KI test indicated no residual hypochlorite in the starch filter cake. After this, the starch filter cake was further mixed with 890 g of fresh, cold tap water. The pH of the starch slurry was adjusted to 6.0 with sulfuric acid. The starch product was further dewatered and dried to a powder with a moisture content of less than 15%.

[0093] The product was subjected to the Brabender test described in the previous example both as a freshly prepared product and as a dry powder after a two-month storage period. The stability of the product at neutral pH is shown in Figure 6. The same product when run at pH 3.0 is shown in Figure 7. These two figures show that no drastic viscosity changes were observed over the two-month storage period. The slight changes were sufficient to allow for acceptable viscosity at pH 9.0 without the need for an additional antioxidant system, as used in WO 2019 / 032011.

[0094] Viscosity profiles during the heating and cooling cycles show that the viscosity response is nearly identical in Figures 6 and 7, with a slightly lower degree of inhibition after 2 months of storage. A slight viscosity decrease is observed during the high temperature hold time in the pH 3.0 run in Figure 7. This is seen in the neutral run in Figure 6 as a slightly more rapid viscosity increase at the onset of granule swelling after storage, but the level of change is very limited.

[0095] Example 4 This example shows that the process can be carried out at lower temperatures and for longer reaction times.

[0096] In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 4.3 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with 3% aqueous sodium hydroxide solution. The temperature was adjusted to 15°C. Active chlorine (107 g / L; density: 1.19 g / cm3) was added. 3 56.9 ml of sodium hypochlorite containing 10% DM starch was added during stirring. The hypochlorite solution added contained a total of 6.1 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine of DM starch. The vessel was left stirring from the afternoon until the next morning (16 hours) while the temperature was kept constant at 15°C. 2.6 g of an antioxidant, i.e., ascorbic acid, was added during stirring. The starch slurry was left stirring for 30 minutes. The starch slurry was dehydrated to 55% DM and further washed with fresh tap water. It was then further mixed with 890 g of fresh, cold tap water. 10.4 g of citric acid was added during stirring. The starch slurry was left stirring for 30 minutes, and the pH of the starch slurry was adjusted to 6.0 with sodium hydroxide. The starch product was further dehydrated and dried to a powder with a moisture content of approximately 15%.

[0097] This product was run and evaluated in the Brabender test described in the previous example using the same product made at 30°C, i.e., the product of Example 1d), with a reaction time of 180 minutes. The results are shown in Figure 8. Figure 8 shows that nearly identical profiles are obtained when the reaction is run at 30°C or 15°C, but the reaction time is longer at the lower temperature.

[0098] Example 5 Products made according to Examples 1d) and 3, in which the addition of ascorbic acid was omitted, demonstrated that the starch produced by this reaction had a good taste profile without the need for additional chemical additions to remove chloramines or haloalkanes. Because the reaction is carried out outside the pH range in which such compounds are produced and hypochlorite ions are washed out before pH neutralization, this results in a product with a comparable taste, regardless of whether ascorbic acid is added as a taste improver.

[0099] Fruit preparations were made using the starches produced from Examples 1d) and 3 above according to the following basic formula: ●Raspberry 30% ●Sugar 30% ●Starch 5% ●Water 35%

[0100] The starch was suspended in water and mixed with raspberries. The mixture was heated on a stove with stirring until boiling. Once the mixture began to boil, sugar was added and dissolved. The fruit preparations were cooled and tested by a trained taste panel.

[0101] Only one tester commented on the maize / corn taste of the fruit preparation prepared from this example. Nine testers commented nothing about the off-taste or off-flavor of two fruit preparations made using different methods of removing active chlorine from the reaction mixture. The comment about the corn flavor is understandable, since the starch is made from corn starch, which is known to interact with the flavor release of delicate foods. The conclusion is that by terminating the reaction at high pH and directly washing out residual hypochlorite ions at high pH before pH neutralization, the risk of off-flavor formation from haloalkanes and chloramines is eliminated. This eliminates one washing step in starch production, allowing fewer chemicals to be used.

[0102] Example 6 This example shows how starch responds to various molar ratios of active chlorine to ammonia at high pH above 10. In various examples where the molar content of ammonia added is kept constant and the active chlorine added is varied, the ratio is varied between 1 / 2 and 4 / 1. The changes upon heating in a Brabender at neutral pH are shown in Figure 9, and the same ratios at pH = 3.0 in Figure 10.

[0103] 6a) In tests conducted at pH 11.5, 0.17% active chlorine and ammonia in DM starch (0.13% nitrogen / DM starch) at a 1 / 2 molar ratio of active chlorine and ammonia. In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 4.3 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with sodium hydroxide solution. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added. 3 14.0 ml of sodium hypochlorite containing 1.5 g of DM starch was added during stirring. The amount of hypochlorite solution added contained a total of 1.5 g of active chlorine. This corresponds to the addition of 0.17% w / w of active chlorine in DM starch. The vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C.

[0104] The starch slurry was dewatered to 55% DM and further washed with fresh tap water until a KI test showed no residual hypochlorite in the starch filter cake. After this, the starch filter cake was further mixed with 890 g of fresh, cold tap water. The pH of the starch slurry was adjusted to 6.0 with sulfuric acid. The starch product was further dewatered and dried to a powder with a moisture content of less than 15%.

[0105] 6b) In tests conducted at pH 11.5, a 1 / 1 molar ratio of active chlorine and ammonia was used for 0.35% active chlorine and ammonia in DM starch (0.13% nitrogen / DM starch). In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 4.3 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with sodium hydroxide solution. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added. 328.0 ml of sodium hypochlorite containing 10% w / w of DM starch was added during stirring. The amount of hypochlorite solution added contained a total of 3.0 g of active chlorine. This corresponds to the addition of 0.35% w / w of active chlorine of the DM starch. The vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C.

[0106] The starch slurry was dewatered to 55% DM and further washed with fresh tap water until a KI test showed no residual hypochlorite in the starch filter cake. After this, the starch filter cake was further mixed with 890 g of fresh, cold tap water. The pH of the starch slurry was adjusted to 6.0 with sulfuric acid. The starch product was further dewatered and dried to a powder with a moisture content of less than 15%.

[0107] 6c) In tests conducted at pH 11.5, 0.70% active chlorine and ammonia in DM starch (0.13% nitrogen / DM starch) at a 2 / 1 molar ratio of active chlorine and ammonia In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 4.3 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with sodium hydroxide solution. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added. 3 58.0 ml of sodium hypochlorite containing 10% w / w of DM starch was added during stirring. The amount of hypochlorite solution added contained a total of 6.0 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine of the DM starch. The vessel was left stirring for 180 minutes and the temperature was maintained at 30°C.

[0108] The starch slurry was dewatered to 55% DM and further washed with fresh tap water until a KI test showed no residual hypochlorite in the starch filter cake. After this, the starch filter cake was further mixed with 890 g of fresh, cold tap water. The pH of the starch slurry was adjusted to 6.0 with sulfuric acid. The starch product was further dewatered and dried to a powder with a moisture content of less than 15%.

[0109] 6d) In tests conducted at pH 11.5, 1.4% active chlorine and ammonia in DM starch (0.13% nitrogen / DM starch) at a 4 / 1 molar ratio of active chlorine and ammonia In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 4.3 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with sodium hydroxide solution. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added. 3 112.0 ml of sodium hypochlorite containing 1.4% w / w of DM starch was added during stirring. The amount of hypochlorite solution added contained a total of 12.0 g of active chlorine. This corresponds to the addition of 1.4% w / w of active chlorine of the DM starch. The vessel was left stirring for 180 minutes and the temperature was maintained at 30°C.

[0110] The starch slurry was dewatered to 55% DM and further washed with fresh tap water until a KI test showed no residual hypochlorite in the starch filter cake. After this, the starch filter cake was further mixed with 890 g of fresh, cold tap water. The pH of the starch slurry was adjusted to 6.0 with sulfuric acid. The starch product was further dewatered and dried to a powder with a moisture content of less than 15%.

[0111] The starch inhibition obtained with varying molar ratios of active chlorine to ammonia according to Examples 6a), 6b), 6c), and 6d) was evaluated when heated in a Brabender Amyloviscograph Model E using distilled water and a 350 cmg torsion spring, run at 75 rpm and at a dry solids level of 5% w / w, and can be seen in Figure 9 for neutral pH and Figure 10 for pH 3.0. It is clear from the profiles that a certain ratio is required to obtain optimum inhibition, and that as the level of active chlorine added exceeds a certain ratio, the viscosity of the starch decreases.

[0112] Example 7 This example shows how starch responds to various molar ratios of active chlorine to ammonia when the molar content of active chlorine added is held constant and the ammonia addition level is varied between 1 / 2 and 4 / 1. Figure 11 shows the response when heated in a Brabender at neutral pH, and Figure 12 shows the same ratios at pH 3.0.

[0113] 7a) In tests conducted at pH 11.5, a 1 / 2 molar ratio of active chlorine and ammonia was used for 0.7% active chlorine and ammonia in DM starch (0.6% nitrogen / DM starch). In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 19.8 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with sodium hydroxide solution. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added. 3 57.0 ml of sodium hypochlorite containing 100% w / w of DM starch was added during stirring. The hypochlorite solution added contained a total of 6.1 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine on the DM starch, 5.2 g of nitrogen from the ammonia source, and a dose of 0.6% of the nitrogen from the ammonia source on the DM starch. The vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C.

[0114] The starch slurry was dewatered to 55% DM and further washed with fresh tap water until a KI test showed no residual hypochlorite in the starch filter cake. After this, the starch filter cake was further mixed with 890 g of fresh, cold tap water. The pH of the starch slurry was adjusted to 6.0 with sulfuric acid. The starch product was further dewatered and dried to a powder with a moisture content of less than 15%.

[0115] 7b) In tests conducted at pH 11.5, a 1 / 1 molar ratio of active chlorine and ammonia in DM starch (0.70% active chlorine and ammonia at 0.3% nitrogen / DM starch) was used. In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 9.9 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with sodium hydroxide solution. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added. 357.0 ml of sodium hypochlorite containing 100% w / w of DM starch was added during stirring. The hypochlorite solution added contained a total of 6.1 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine on the DM starch, 2.6 g of nitrogen from the ammonia source, and a dose of 0.3% of the nitrogen from the ammonia source on the DM starch. The vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C.

[0116] The starch slurry was dewatered to 55% DM and further washed with fresh tap water until a KI test showed no residual hypochlorite in the starch filter cake. After this, the starch filter cake was further mixed with 890 g of fresh, cold tap water. The pH of the starch slurry was adjusted to 6.0 with sulfuric acid. The starch product was further dewatered and dried to a powder with a moisture content of less than 15%.

[0117] 7c) In tests conducted at pH 11.5, 0.70% active chlorine and ammonia in DM starch (0.15% nitrogen / DM starch) at a 2 / 1 molar ratio of active chlorine and ammonia In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 5.0 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with sodium hydroxide solution. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added. 3 57.0 ml of sodium hypochlorite containing 100% w / w of DM starch was added during stirring. The hypochlorite solution added contained a total of 6.1 g of active chlorine. This corresponds to the addition of 0.70% w / w of active chlorine on the DM starch, 1.3 g of nitrogen from the ammonia source, and a dose of 0.15% of the nitrogen from the ammonia source on the DM starch. The vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C.

[0118] The starch slurry was dewatered to 55% DM and further washed with fresh tap water until a KI test showed no residual hypochlorite in the starch filter cake. After this, the starch filter cake was further mixed with 890 g of fresh, cold tap water. The pH of the starch slurry was adjusted to 6.0 with sulfuric acid. The starch product was further dewatered and dried to a powder with a moisture content of less than 15%.

[0119] 7d) In tests conducted at pH 11.5, 0.70% active chlorine and ammonia in DM starch (0.075% nitrogen / DM starch) at a 4 / 1 molar ratio of active chlorine and ammonia In a reaction vessel, 869.1 g of DM waxy maize starch was mixed with 1600 g of cold tap water. 2.5 g of NH4Cl was added and dissolved. After this, the pH was adjusted to 11.5 with sodium hydroxide solution. The temperature was adjusted to 30°C. The active chlorine (107 g / L; density: 1.19 g / cm3) was added. 3 57.0 ml of sodium hypochlorite containing 0.70% w / w of DM starch was added during stirring. This corresponds to the addition of 0.65 g of nitrogen from the ammonia source, and a dose of 0.075% of the nitrogen from the ammonia source on the DM starch. The vessel was left stirring for 180 minutes, and the temperature was maintained at 30°C.

[0120] The starch slurry was dewatered to 55% DM and further washed with fresh tap water until a KI test showed no residual hypochlorite in the starch filter cake. After this, the starch filter cake was further mixed with 890 g of fresh, cold tap water. The pH of the starch slurry was adjusted to 6.0 with sulfuric acid. The starch product was further dewatered and dried to a powder with a moisture content of less than 15%.

[0121] The starch inhibition obtained with varying molar ratios of active chlorine to ammonia according to Examples 7a), 7b), 7c), and 7d) was evaluated when heated in a Brabender Amyloviscograph Model E running at 75 rpm and 5% w / w dry solids level using distilled water and a 350 cmg torsion spring, and can be seen in Figure 11 for neutral pH and Figure 12 for pH 3.0. It is clear from the profiles that the molar ratio of active chlorine to ammonia affects the inhibition level, and that keeping the active chlorine addition level constant and varying the ammonia level increases the amount of ammonia, i.e., decreases the molar ratio of active chlorine to ammonia, and increases the viscosity.

[0122] While the invention has been described with reference to numerous embodiments, those skilled in the art will recognize that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the invention without departing from essential scope thereof. Therefore, it is not intended that the invention be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but the invention is intended to include all embodiments falling within the scope of the appended claims.

Claims

1. A method for preparing an inhibited starch, comprising the following steps a) to d) performed in alphabetical order: a) providing a slurry comprising granular starch obtained from a starch containing raw material; b) alkalizing the slurry by adding ammonia or by adding one or more compounds capable of releasing or generating ammonia in the slurry, The one or more compounds capable of releasing or generating ammonia in the slurry are i) an ammonium compound and a hydroxide compound which is reacted to release ammonia from said ammonium compound; ii) an enzyme to release ammonia from the amino acids already present in the slurry; iii) an oxidizing agent to release ammonia from the α-amino acids already present in the slurry; or iv) an amide which releases ammonia in the slurry; This is the process c) adjusting the pH of the slurry to a value greater than 10.0; and d) adding at least one oxidant to said slurry for reaction with said ammonia; A method comprising: Here, the inhibited starch is one in which the swelling of starch granules after reaching the gelatinization point when the starch granules are heated in water is inhibited.

2. A method for preparing an inhibited starch, comprising the following steps a) to c) performed in alphabetical order: a) providing a slurry comprising granular starch obtained from a starch containing raw material; b) directly alkalizing the slurry to a pH between 10.0 and 12.0; and c) adding chloramine or dichloramine to the slurry; A method comprising: Here, the inhibited starch is one in which the swelling of starch granules after reaching the gelatinization point when the starch granules are heated in water is inhibited.

3. A method for preparing an inhibited starch, comprising the following steps a) to e) performed in alphabetical order: a) providing a slurry comprising granular starch obtained from a starch containing raw material; b) alkalizing the slurry by adding ammonia or by adding one or more compounds capable of releasing or generating ammonia in the slurry, The one or more compounds capable of releasing or generating ammonia in the slurry are i) an ammonium compound and a hydroxide compound which is reacted to release ammonia from said ammonium compound; ii) an enzyme to release ammonia from the amino acids already present in the slurry; iii) an oxidizing agent to release ammonia from the α-amino acids already present in the slurry; or iv) an amide which releases ammonia in the slurry; This is the process c) adjusting the pH of the slurry to a value between 7.0 and 10.0; d) adding at least one oxidant to said slurry for reaction with said ammonia; and e) adjusting the pH of the slurry to a value greater than 10.

0. A method comprising: Here, the inhibited starch is one in which the swelling of starch granules after reaching the gelatinization point when the starch granules are heated in water is inhibited.

4. 2. The method of claim 1, wherein in step c) the pH of the slurry is adjusted to a value up to 12.

0.

5. The method of claim 4, wherein the pH is adjusted to a value between 11.0 and 11.

5.

6. The method of claim 3, wherein in step e) the pH of the slurry is adjusted to a value up to 12.

0.

7. A method according to any one of claims 1 and 3 to 6, wherein in step b), the one or more compounds capable of releasing or generating ammonia in the slurry are i) an ammonium compound and a hydroxide compound which is reacted to release ammonia from the ammonium compound, and the ammonium compound is an ammonium salt of an acid.

8. 8. The method of claim 7, wherein the ammonium salt of an acid is ammonium acetate, ammonium chloride, or ammonium citrate.

9. 9. The method of claim 7 or 8, wherein the hydroxide compound is an alkali metal or alkaline earth metal hydroxide.

10. The method of claim 1, wherein in step b), the one or more compounds capable of releasing or generating ammonia in the slurry are iv) an amide and further comprise an alkali or an acid.

11. 11. The method of any one of claims 1 and 3 to 10, wherein at least one organic acid, bisulfite, or hydrogen peroxide is added to the slurry after step d) for the purpose of removing residual oxidizing agent, off-tastes, and undesirable odors.

12. The method of claim 11, wherein at least one organic acid is added to the slurry after step d), the at least one organic acid being citric acid, erythorbic acid, adipic acid, lactic acid, ascorbic acid, and succinic acid, and salt forms of these acids.

13. 12. The method of claim 11, wherein the at least one organic acid, bisulfite, or hydrogen peroxide is added in an amount of 0.001-5% w / w of the DM starch.

14. 14. The method of claim 13, wherein the at least one organic acid, bisulfite, or hydrogen peroxide is added in an amount of 0.01-3% w / w of the DM starch.

15. 15. The method of claim 14, wherein the at least one organic acid, bisulfite, or hydrogen peroxide is added in an amount of 0.05-1% w / w of the DM starch.

16. 16. The method of any one of claims 1 and 3 to 15, wherein the ammonia added to or released or produced in the slurry is present in an amount of 0.01 to 10% w / w of the starch slurry of DM starch.

17. 17. The method of claim 16, wherein the ammonia added to or released or generated in the slurry is present in an amount of the starch slurry from 0.03 to 5% w / w of DM starch.

18. 18. The method of claim 17, wherein the ammonia added to or released or generated in the slurry is present in an amount of the starch slurry from 0.05 to 3.0% w / w of DM starch.

19. The method of claim 1, wherein the oxidant in step d) is a source of active chlorine and is hypochlorite, hypochlorous acid, or chlorine dissolved in water.

20. 20. The method of claim 19, wherein the hypochlorite is an alkali metal or alkaline earth metal hypochlorite.

21. 21. The method of claim 20, wherein the alkali metal or alkaline earth metal hypochlorite is sodium hypochlorite, calcium hypochlorite, magnesium hypochlorite, or potassium hypochlorite.

22. 22. The method according to any one of claims 19 to 21, wherein the molar ratio between active chlorine and the ammonia added is in the ratio range of 1 / 4 to 4 / 1.

23. The method of claim 1, wherein the reaction temperature during step d) is 5 to 70°C.

24. A method according to any one of claims 1 and 3 to 23, wherein the oxidizing agent in step d) is added in an amount of 0.03 to 30% w / w of DM starch.

25. The method of claim 24, wherein the oxidizing agent in step d) is added in an amount of 0.05-10% w / w of DM starch.

26. The method of claim 25, wherein the oxidizing agent in step d) is added in an amount of 0.1-4% w / w of DM starch.

27. The method of claim 2, wherein at least one organic acid, bisulfite, or hydrogen peroxide is added to the slurry after step c) for the purpose of removing residual oxidizing agent, off-tastes, and undesirable odors.

28. The method of claim 27, wherein at least one organic acid is added to the slurry after step c), the at least one organic acid being citric acid, erythorbic acid, adipic acid, lactic acid, ascorbic acid, and succinic acid, and salt forms of these acids.

29. The method of claim 29, wherein the starch to be inhibited is potato starch, maize (corn) starch, tapioca starch, barley starch, rice starch, wheat starch, rye starch, oat starch, amaranth starch, quinoa starch, sago starch, bean starch, pea starch, red seaweed starch (Floridian 29. The method of any one of claims 1 to 28, wherein the starch is a native granular or modified starch selected from the group consisting of waxy potato starch, waxy maize starch, waxy tapioca starch, waxy barley starch, glutinous rice starch, waxy sorghum starch, waxy wheat starch, waxy bean starch, and high amylose starch, or a combination of two or more thereof.

30. 30. The method of any one of claims 1 to 29, wherein the starch may be modified prior to being provided to the slurry in step a) or the inhibited starch may be modified after preparation, wherein the starch is modified by acetylation, hydroxypropylation, chemical cross-linking, OSA modification, enzyme treatment, dextrinization, gelatinization to render the starch cold water soluble, pre-inhibition gelatinization to render the starch cold water swelling, and combinations of two or more thereof.

31. The method according to any one of claims 1 to 30, wherein hard water is used in step a), and the inhibited starch is distinguished as having a higher viscosity than when distilled water is used.

32. 32. The method of any one of claims 1 to 31, wherein the inhibited starch has improved warehouse storage stability.

33. 33. The method of claim 31 or 32, wherein the inhibited starch is used as an ingredient in a food product.

34. 34. The method of claim 33, wherein the food products can be selected from sauces; soups; dairy products and yogurts; batters and breadings; dairy and / or fruit preparations for baked goods; and milk-based desserts.

35. The method of claim 34, wherein the dairy product is a fermented Creme Fraiche; the fruit preparation is a bake stable fruit preparation; and the milk-based dessert is a pudding, a vanilla sauce, an ice cream, or a mousse.

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