MX2008003037A - Production of crystalline short chain amylose - Google Patents

Abstract

A process for producing a starch comprises treating a feed starch that comprises amylopectin with glucanotransferase to produce a chain-extended starch, and treating the chain- extended starch with a debranching enzyme to produce a starch product that comprises amylose fragments. At least about 38%by weight of the amylose fragments have a degree of polymerization (DP) of at least about 35.

Description

PRODUCTION OF CRYSTALLINE SHORT CHAIN AMYLOSA Starch comprises two polysaccharides: amylose and amylopectin. Amylose is a generally linear polymer comprising glucose units connected by alpha 1-4 glycosidic bonds. Amylopectin is a branched polymer in which many of the glucose units are connected by alpha 1-4 glycosidic bonds, but some are connected by alpha 1-6 glycosidic bonds. Alpha amylase is an enzyme that is present in the human body and that hydrolyzes alpha 1-4 bonds in starch, thus leading to the digestion of starch. In certain situations it is desirable to produce starch that resists hydrolysis by alpha-amylase, for example to lower the caloric content of the starch or to increase its dietary fiber content. However, attempts to produce such starch in the past have suffered from one or more problems, such as high cost. Amylase-resistant starch is usually produced from high amylose starch, which is often expensive. There is a need for improved processes to produce starch with a high amylose content that is suitable for the production of alpha-amylase-resistant starch.

BRIEF DESCRIPTION OF THE INVENTION One embodiment of the invention is a process for producing a starch. The process comprises treating a feed starch comprising amylopectin with glucanotransferase to produce an extended starch in the chain, and treating the extended starch in the chain with a debranching enzyme to produce a starch product comprising fragments of amylose. At least about 38% by weight of the amylose fragments have a degree of polymerization (DP) of at least about 35. The process can optionally further include recovery of the amylose fragments. As another option, the process may include membrane filtration of a solution or dispersion of the starch product to increase the concentration of amylose fragments having a degree of polymerization (DP) of at least about 35. Another embodiment of the present invention invention is a starch product produced by the process described above. In some embodiments of the invention, at least 40% by weight of the amylose fragments have a degree of polymerization (DP) of at least about 35. If the process used to make the starch product includes membrane filtration, then in some embodiments at least about 50% by weight of the amylose fragments have a degree of polymerization (DP) of at least about 35. In some cases the starch product has a peak melting temperature of greater than about 105 °. C. The amylose in the starch can be crystallized to increase its resistance to alpha-amylase. Another embodiment of the invention is a food product that contains the starch described in the foregoing. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1-45 are described in the following pages. DESCRIPTION OF SPECIFIC MODALITIES One embodiment of the present is a process for producing starch having a relatively high content of amylose. This process includes treating a feed starch comprising amylopectin with glucanotransferase to extend at least some of the starch chains, and treating the extended starch in the chain with a debranching enzyme to produce amylose fragments. These amylose fragments can then be crystallized to produce a resistant starch product. Ordinary toothed corn starch can be enzymatically debranched to give short chain amylose fragments, but since the amylopectin component of the starch is usually composed of relatively short branched chains, the product contains very few of the longer chain lengths than they are needed for the resistance of the enzyme. Degrated serrated maize starch that has not been modified with a glucanotransfera typically contains less than 35% of the DP35 and higher chain lengths (ie, starch molecules that have a degree of polymerization of at least 35) and therefore do not have the thermal stability necessary for a resistant starch. In addition, the debranched toothed starch contains a fraction of long chain lengths of amylose as well as short chains of amylopectin. This combination of heterogeneous chain lengths is not optimal for crystallization and amylase resistance. The feed starch used in the present process can come from a variety of sources, including toothed corn, waxy corn, high amylose genetic corn (ae is the name of a genetic mutation commonly known to corn growers and is short to "spread amylose"), potatoes, tapioca, rice, peas, wheat, waxy wheat, as well as amylose purified from these starches, and alpha- 1,4 glucans produced according to patent application WO 00/14249, which is incorporated herein by reference, and combinations of two or more of these starch sources. Chemically modified starches, such as hydroxypropyl starches, starch adipates, acetylated starches and phosphorylated starches, may also be used in the present invention. For example, suitable chemically modified starches include, but are not limited to, crosslinked starches, acetylated and organically esterified starches, hydroxyethylated and hydroxypropylated starches, phosphorylated and inorganically esterified starches, cationic, anionic, nonionic, and zwitterionic starches, and starch derivatives of succinate and substituted succinate. Such modifications are known in the art, for example, in Modified Starches: Properties and Uses, Ed. Wurzburg, CRC Press, Inc., Florida (1986). Other suitable modifications and methods are disclosed in U.S. Patent Nos. 4,626,288, 2,613,206 and 2,661,349, which are incorporated herein by reference. If the feed starch is a waxy starch, it can be at least partially debranched by treatment with a debranching enzyme prior to treatment with glucanotransferase. Suitable debranching enzymes for this purpose include pullulanase and isoamylase. This provides a source of fragments that will be transferred by the glucanotransferase to the non-reducing ends of amylopectin, resulting in longer branched chains. 4-a-glucanotransferase [2.4.1.25] is an enzyme that catalyzes the transfer of a segment of a 1,4-alpha-D-glucan to a new position in an acceptor, which can be glucose or another 1, 4- Alpha-D-glucan. The glucanotransferase will catalyze the transfer of a portion of maltosyl to a maltotriose acceptor, releasing glucose. The released glucose can be used as a measure of enzyme activity. A suitable assay for determining the glucanotransferase activity is as follows. In this assay, maltotriose is used both as a substrate and molecule acceptor molecule. Glucose is released in this reaction and can be measured after a modified version of the common glucose oxidase / peroxidase assay (Werner, W. et al., (1970) Z. Analyt, Chem. 252: 224). The GOD-Perid solution can be obtained from the WAKO Glucose Cleaner Kit, or it can be prepared with 65 mM sodium phosphate, pH 7 including 0.4 g / 1 glucose oxidase (Sigma G6125 or G7773), 0.013 g / 1 HRP (Sigma P8125), and 0.65 g / 1 ABTS (Calbiochem # 194430). A solution of 0.04N NaOH is also used. The substrate solution is 1% maltotriose (0.1 g of maltotriose in 10 ml of 50 mM phosphate buffer at pH 6.0). Standard curve: glucose solution: weighs 0.1806 g of glucose in 500 ml MQ H20. Dilutions for the standard curve: 120 μl of the substrate solution is preincubated at a selected temperature, for example, 60 ° C, for 10 minutes. 20 μl of an enzyme solution is added to the substrate solution and the reaction mixture is incubated at 60 ° for 10 minutes. The reaction is stopped by the addition of 20 μl of 0.04N NaOH. 20 μl are then transferred to a 96-well microtiter plate and 230 μl of GOD-Perid solution is added. After 30 minutes at room temperature, the absorbance is measured at 420 nm. The activity of the enzyme is calculated in relation to the standard glucose curve in the range of 0-0.5 μmol glucose. One unit (U) of activity is defined as the amount of enzyme that liberates 1 μmol of glucose / minute. The treatment of the feeding starch with glucanotransferase produces extensions of chains in the amylopectin molecules. This treatment can be done, for example, in aqueous solution or suspension at a temperature of about 70-100 ° C and a pH of about 5.0 - 6.0. As a result, the DP35 and the highest content of the final product increased by above 38%, or in some cases by above 40%, and the chain lengths are much more uniform, as indicated by a polydispersity of 2- 4, compared to about 8 for debranched toothed corn starch. In some embodiments of the invention, the glucanotransferase dosage may be about 1-15 ml per 100 grams of starch, preferably about 5-12 ml / 100 g. The glucanotransferase can be contacted with the starch in a single dosage, or spread over multiple dosages. In one embodiment of the invention, the total dosage is divided into three portions that are provided at separate times (eg, three separate dosages of 2.5 ml / 100 g each), with at least one hour between each. In some embodiments, the reaction temperature may be about 75-85 ° C, and the reaction time may be less than about 8 hours, preferably less than about 6 hours. Optionally, a material based on additional starch can be added to the extended starch in the chain prior to debranching. For example, a maltodextrin can be added. The starch extended in the resulting chain can then be treated with a debranching enzyme, such as isoamylase or pullulanase, for example at a temperature of about 30-60 ° C and a pH of about 4.0-5.0 to produce amylose fragments having Desirable lengths. In certain embodiments of the invention, the dosage of isoamylase is about 1-10 mg per g of starch, preferably about 1-5 mg / g. DP35 and high content can be enriched by up to 50% by fractionation by microfiltration at an elevated temperature, such as about 60-120 ° C, more typically about 60-90 ° C, and even more typically 70-85 ° C. . The product of debranched starch, treated with glucanotransferase, after microfiltration can have a peak melting temperature of greater than about 105 ° C, and can contain at least about 80% by weight resistant starch after heating in water at about 98 °. C. Optionally, the product starch can be heat treated in an aqueous solution or suspension at a temperature of at least 90 ° C, or in some embodiments at least about 98 ° C. This heat-wet treatment can increase the total dietary fiber (TDF) contained in the starch in some examples. For example, the heat-wet treatment may increase the TDF of the starch from about 15-35% to about 75-80% in some embodiments of the invention. In one embodiment of the process, the feed starch is suspended in water at 15% solids and the pH is adjusted to 5.5 with dilute NaOH. The suspension is placed in an autoclave and heated at 140 ° C for 30 minutes. After cooling to 85 ° C and adjusting the pH to 5.5, the glucanotransferase is added and allowed to react for 24 hours. The enzyme is deactivated by lowering the pH below 3.0. The starch is redispersed by heating at 140 ° C for one hour and then cooled to 45 ° C, and the pH is adjusted to 4.5. The isoamylase is added and allowed to react for 18-24 hours. The mixture is heated at 85 ° C for one hour to deactivate the enzyme. If necessary, the product can be treated again with isoamylase by repeating the heating at 140 ° C and the treatment of the enzyme at 45 ° C and the pH at 4.5. The product can then be fractionated to increase the content of long chain components. This can be carried out, for example, by microfiltration of the crystallized debranched product at a temperature of at least about 80 ° C using a ceramic membrane with pore size of about 0.45 microns. After collecting 1.5 to 2.5 volumes of product retained in relation to the volume of the starting suspension, while retaining the volume of the product retained by the addition of deionized water, the product is isolated by concentration and spray dried or by centrifuging and drying the retained product in the oven. The product produced by the process contains a high percentage of amylose that is suitable for making starch that is resistant to alpha-amylase. The resistant starch can be added to a number of food products, to reduce its glycemic index, and increase dietary fiber and the probiotic effect in the colon. The starch produced by this process can be used as a bulk agent or a substitute for flour in foods, such as reduced-calorie baked goods. Starch is also useful for the fortification of dietary fiber in foods. Specific examples of foods in which starch can be used include bread, snack foods, cookies, cookies, extruded snacks, soups, frozen desserts, fried foods, pasta products, potato products, rice products, corn products, wheat products , dairy products, nutritional bars, diabetic foods and beverages. The starch product, at least in some embodiments, is thermally stable in water at a temperature of at least about 90 ° C, or in some cases at least about 100 ° C, which allows it to be used in food products that will be processed in conditions of high temperature and humidity.

Certain embodiments of the invention are described in the following examples. EXAMPLE 1 170 g of common corn starch (Minstar 2030) were suspended with 830 ml of urban water in a 300 ml glass beaker. The pH was adjusted to 5.5 with NaOH / HCl and the suspension was carefully heated to 65-70 ° C under constant stirring to form a thick gel. A lid was placed on the glass beaker which was then transferred to an autoclave. When the vapor pressure had reached 40 psi (140 ° C) the conditions were maintained for 30 minutes, after which the autoclave was allowed to cool. The cooked starch was transferred to a stirred glass reactor and the conditions were adjusted to 85 ° C, pH 5.5. The 1.07 ml of T. thermophilus glucanotransferase, corresponding to 10 μg of enzyme protein / g of DS, were added and the reaction was allowed to continue for 24 hours. The reaction was stopped by reducing the pH below 3.0. Example 2 In order to generate suitable donor molecules for the glucanotransferase, the following experiment was carried out. 175 g of waxy corn starch (Cerestar 04201) was suspended with 830 ml of urban water in a 3000 ml glass beaker. The pH was adjusted to 5.5 with NaOH / HCl and the suspension was carefully heated to 65-70 ° C under constant stirring to form a thick gel. A lid was placed in the glass beaker which was then transferred to an autoclave. When the vapor pressure had reached 40 psi (140 ° C) the conditions were maintained for 30 minutes, after which the autoclave was allowed to cool. The cooked starch was then partially debranched after it has been transferred to a stirred glass reactor. The temperature was adjusted to 55 ° C, pH 4.3, and 0.0872 g of isoamylase from Pseudomonas amiloderamosa (350,000 IA units / g, from Hayashibara), were added, corresponding to 200 units of isoamylase / g of DS. The reaction was then allowed to continue for 3 hours. After partial debranching, the temperature was increased to 85 ° C and the pH was adjusted to 5.5 with NaOH 1.10 ml of T. thermophilus glucanotransferase, corresponding to 10 μg enzyme protein / g of DS, were added and the reaction was allowed to continue for 24 hours. The reaction was stopped by lowering the pH below 3.0. Example 3 In order to test whether the degree of modification of starch by glucanotransferase plays a crucial role, 170 g of common corn starch (Minstar 2030) was suspended with 830 ml of urban water in a 3000 ml glass flask.

The pH was adjusted to 5.5 with NaOH / HCl and the suspension was carefully heated to 65-70 ° C under constant stirring to form a thick gel. A lid was placed on the glass flask which was then transferred to an autoclave. When the vapor pressure had reached 40 psi (140 ° C), the conditions were maintained for 30 minutes, after which the autoclave was allowed to cool. The cooked starch was transferred to a stirred glass reactor and the conditions were adjusted to 85 ° C, pH 5.5. 1.10 ml of T. thermophilus glucanotransferase, corresponding to 10 μg of enzyme protein / g of DS, were added. After 2 hours, an addition of 1.10 ml of T. thermophilus glucanotransferase was made and the reaction was allowed to continue for 27 hours. In addition, an addition of 1.10 ml of T. thermophilus glucanotransferase was then made and the reaction was allowed to continue overnight. The reaction was stopped by reducing the pH below 3.0. Example 4 A sample of the dentate starch treated with glucanotransferase of Example 1 was received as a frozen suspension. After storing a 50 g sample of the thawed suspension, the remaining suspension (495.3 g) was diluted with 200 g of deionized water and the pH adjusted to 6.5 with 5% NaOH. The suspension was placed in a stirred high pressure reactor. After purging with nitrogen, the reactor was heated to 140 ° C for 1 hour, and then cooled to 105 ° C. The product was removed from the reactor when purging through a valve connected to a dip tube in a 3-neck round bottom flask. The flask was placed in a water bath at 45 ° C and the pH was adjusted to 4.5 by adding dilute HCl. When the temperature of the solution reached 45 ° C, 18 mg (300 units / gram of starch) of Hayashibara isoamylase was added. The solution was left stirring overnight. The enzyme was deactivated on heating at 85 ° C for 1 hour. Example 5 A sample of partially de-branched waxy starch treated with glucanotransferase of Example 2 was received as a frozen suspension. After storing a 50 g sample of the thawed suspension, the remaining suspension (469.0 g) was diluted with 200 g of deionized water and the pH adjusted to 6.5 with 5% NaOH. The suspension was placed in a stirred high pressure reactor. After purging with nitrogen, the reactor was heated to 150 ° C for 1 hour, and then cooled to 105 ° C. The product was removed from the reactor when purging through a valve connected to a dip tube in a 3-neck round bottom flask. The flask was placed in a water bath at 45 ° C and the pH was adjusted to 4.5 by adding dilute HCl. When the temperature of the solution reached 47.7 ° C, 18 mg of Hayashibara isoamylase was added. The solution was left stirring at 45 ° C overnight. The enzyme was deactivated by raising the pH to 6.3 with 5% NaOH and heating at 85 ° C for 1 hour. Example 6 A sample of the dentate starch treated with glucanotransferase of Example 3 was received as a frozen suspension. After storing a 50 g sample of the thawed suspension, the remaining suspension (473.0 g) was diluted with 500 g of deionized water and the pH adjusted to 6.5 with 5% NaOH. The suspension was placed in a stirred high pressure reactor. After purging with nitrogen, the reactor was heated to 140 ° C for 1 hour, and then cooled to 95 ° C. The product was removed from the reactor when purging through a valve connected to a dip tube in a 3-neck round bottom flask. The flask was placed in a water bath at 45 ° C and the pH was adjusted to 4.5 by adding 2 drops of acetic acid and a few drops of 5% NaOH. When the temperature of the solution reached 45 ° C, 40 mg (300 units / gram of starch) of Hayashibara isoamylase was added. The solution was left stirring overnight. After adjusting the pH to 6.0, the sample was heated to 95 ° C in a water bath and stirred for 1 hour. The flask was then placed in a water bath at 45 ° C and the pH adjusted to 4.5 with dilute HCl and 30 mg of Hayashibara isoamylase was added when the temperature of the solution reached 45 ° C. After stirring overnight, the pH was adjusted to 6.0 and heated to 85 ° C for 1 hour. The molecular distribution data shows that this sample was not completely debranded, indicated by the presence of a significant amount of a >material16,000 Dalton. The sample was adjusted to pH 6.5 with 5% NaOH and heated as described above at 140 ° C for 1 hour in a stirred high pressure reactor. The sample was removed from the reactor and placed in a flask in a water bath at 55 ° C and the pH adjusted to 4.5. After the solution reached 55 ° C, 79 mg of Hayashibara isoamylase was added. After stirring at 55 ° C overnight, analysis of this suspension showed that the debranching was complete. Example 7 Results of gel permeation chromatography (GPC) analysis of debranched starches are shown in Table 1. Table 1 Analysis of Glucanotransferase-treated De-branched Starches "DP" means degree of polymerization. "Mw" means weight average molecular weight. "Mn" means number average molecular weight. Example 8 Microfitration was carried out in a system comprising a tank with a heating jacket connected to a recirculation pump and a housing containing a Millipore ceramic membrane of 0.45 microns. The jacket was heated with a circulating oil bath and the membrane housing was heated with an electrical heating tape. The membrane housing was generally maintained at 10-15 ° C higher than the deposition temperature to avoid crystallization of the debranched material in the membrane. The debranched dentate starch suspension treated with glucanotransferase of Example 6 (1056.9 g in about 5% solids) was diluted with 297 g of deionized water and heated in the microfiltration tank with recirculation at 80 ° C and maintained for 1 hour before starting to remove the permeate product from the membrane housing. As an permeate, an equal volume of deionized water was collected, added to the tank. Afterwards, 3360 grams of permeate product were collected, the retained product (1236 g) was removed from the tank and allowed to cool in a vessel located in a refrigerator. The retained product contained 34.1 g of dry solids and the permeate contained 9.0 g of dry solids. The retained product was isolated by dilution of the suspension with 3A ethanol, filtration and drying. The molecular weight of the debranched starch treated with glucanotransferase and the fractions of retained product and the permeate product by microfiltration were analyzed by GPC. The retained product was tested for resistant starch (% RS). Resistant Starch as defined by Englyst (Eur. J. Clinical Nut, 1992), 46, (Suppl 2), S33-S50) is a measure of the amount of starch that is resistant to hydrolysis by alpha-amylase of porcine pancreatin at 37 ° C after two hours of treatment. The result is given as a percent of the initial weight of dry starch.

Results are shown in table 2.

Table 2 Fractionation of Microfiltration of Decholded Serrated Starch Treated with Glucanotransferase (80 ° C) In Table 2, "2.5 / 1" indicates that the sample was washed and that 2.5 liters of permeate were collected per liter of starting sample. EXAMPLE 9 Treatment of Toothed Starch with GT Enzyme: Pearl-C Serrated Starch (15%) was fired (285-290 ° F), the pH was adjusted to 5.7, 4-a-glucanotransferase (GT) was added [2.4 .1.25] (10 ml / 100 g of starch), and reacted at 80 ° C for 4 hr. The starch suspension was heated at 140 ° C for 1 hr, the suspension was incubated at 55 ° C, pH 4.5, isoamylase (1 mg / g starch) was added and the suspension was incubated for 24 hr. The starch suspension was maintained at room temperature, and then stored at 4 ° C.

De-branching of GT-treated starch in DMSO solution: The debranching of GT-treated starch in an experiment in which STAR-DRI® 10 maltodextrin (Tate and Lyle, Decatur, Illinois) was conducted in a DMSO solution. Dry starch (35 mg) was dissolved in 1 ml of aqueous DMSO (DMSO: water = 9: 1 v / v) or wet samples (269 mg, 13% of DS in samples treated with GT) were dissolved in 0.9 ml of Pure DMSO The starch solution was heated in a boiling water bath with stirring for 3 hr. The starch solution was then cooled to 39 ° C, and 3.5 ml of hot sodium acetate buffer (39 ° C, 50 mM) was added. 100 μl isoamylase was added [10 mg / ml isoamylase (1,280,000 U / g solid) in 0.1N NaOAc buffer, pH 4.5] to the starch solution. The mixture of starch and isoamylase was incubated in a water bath at 39 ° C for 2 hr. The mixture of starch and isoamylase was heated in boiling water for 20 min, and then cooled to below 39 ° C. 100 μl isoamylase was added and the mixture was incubated for 16 hr. After debranching, the starch solution was heated in a boiling water bath for 20 min, and cooled to the hot temperature. A 2 mL aliquot of the mixture was diluted with 2 mL of pure DMSO. The DMSO mixtures (approximately 5 mg starch / ml) were heated in a boiling water bath for 20 min, allowed to cool to hot temperature. Dowex resin MR-3 (0.5 g) was added to the starch solution and stirred for 1 min to remove the NaOAc. The starch solution was filtered through a Millipore filter of 0.45 μm pore size fitted to a 3 ml syringe. The filtered samples were injected in the HPLC with the SEC or GPC column. Figure 1 shows the total dietary fiber (TDF) content of different portions of toothed starch converted with GT. If the microfiltration was not used, the converted converted starch was filtered using filter paper, and dried in the oven (50 ° C). The TDF value was 16.8% before the heat-wet treatment, and 80% after the heat-wet treatment. When the microfiltration was used, the retained product had a TDF of 33.84% before the heat-wet treatment and 77.6% after the heat-wet treatment. The permeate product had small solid solids precipitated at 4 ° C, thus the TDF was not analyzed. When drying everything in the product retained and in the permeate product, a dry plate was used in an oven (100 ° C), the estimated solids were 71.4% for the product retained and 28.6% for the permeate product. Figure 2 shows chromatograms of GT-treated resistant starch that was debranched using 1 mg of isoamylase / g of starch in the reactor for 24 hr, and further was debranched by analytical debranching. The microfiltration of the retained product had a maximum DP of about 35, while the microfiltration of the permeated product had a maximum DP of about 14. The filter paper of the retained product had a maximum DP of about 30. Figure 3 shows chromatograms of treated resistant starch with GT that has been debranched using 1 mg of isoamylase / g of starch during 24 hr in the process, and the resistant starch treated with GT also debranched by analytical debranching. Figure 3 shows that the converted starch with GT was almost completely debranched in the reactor using 1 mg isoamylase / g of starch for 24 hr. Figures 4 and 5 show percentages of different DP ranges of three portions of converted GT starches. The microfiltration of the retained product had approximately 38% DP 37-100, 59% DP 25-100, 10% DP 1-12, and 34% DP 1-24. Microfiltration of the permeate product had approximately 12% DP 37-100, 26% DP 25-100, 40% DP 1-12, and 74% DP 1-24. The filter paper of the retained product had approximately 33% DP 37-100, 52% DP 25-100, 14% DP 1-12, and 39% DP 1-24. Table 3. Percentages of Different DP Intervals in Starch Converted with GT When the converted precipitated starch was filtered using filter paper, and the retained product was dried in the oven (50 ° C). The differential scanning calorimetry (DSC) data showing two maximum melting points of 116.03 ° C (13.74 J / g) and 138.79 ° C (0.3879 J / g) before the heat-wet treatment (Fig. 6), and two melting peaks at 117.45 ° C and approximately 140 ° C with the total enthalpy of 21.23 J / g after the heat-moisture treatment (Fig. 7). The heat-wet treatment was at 250 ° F for 1.5 hours at 25% humidity. When the retained product was collected using microfiltration, the DSC data shows two melting peaks of 114.9 ° C and 138.79 ° C with a total enthalpy of 9.83 J / g after the heat-moisture treatment (Fig. 8), and two peaks. of fusion at 117.07 ° C and approximately 140 ° C with a total enthalpy of 21.50 J / g after heat-moisture treatment (Fig. 9). EXAMPLE 10 Treatment of Toothed Starch with GT Enzyme: Pearl-C Serrated Starch (DS 89.56%) was weighed (502.5 g), and 2497.5 g of deionized water (Dl) and 135 mg of CaCl2'2H20 was added to the starch (slurry). 15% starch). The pH of the starch suspension was adjusted to 5.5 using a 2N NaOH solution. The starch suspension was fired (285-290 ° F, 140-143 ° C), and usually the dry solids decreased 15% to 13.19%. The pH was adjusted to 5.7 if it was different. 550 g of starch suspension were weighed in each of the various 1000 ml reactors. The GT enzyme was added according to the amount of dry solids in each of the reactors, as explained further below. The mixture of starch and GT enzyme was incubated in a water bath at 80 ° C up to 24 hr. The samples (approximately 5 ml) were removed to analyze the length of branching chain. De-branching of the converted starch with GT: A sample converted with wet GT (approximately 13% dry solids) was heated with the hermetic microwave lid to full power until it became a fluid. The samples (192125 mg) were weighed into 10 ml tubes, and 2.5 ml of purified water (HPLC grade) was added. For a dry sample, 25 mg of dry starch was weighed to be dissolved in 2.5 ml of purified HPLC grade water. The starch was solubilized in solution (approximately 1% solid) by microwaves. The solution of hot starch in hot potable water (approximately 50 ° C), and 50 μl of isoamylase [10 mg / ml isoamylase (1,280,000 U / g solid) in 0.1N NaOAc buffer, pH 4.5] was added to the solution. starch solution. The mixture of starch and isoamylase was incubated in an oven at 55 ° C for 2 hr. The mixture of starch and isoamylase was heated above 100 ° C to inactivate the isoamylase. The starch solution was cooled using hot potable water (approximately 50 ° C), and 0.1 g of Dowex MR-3 resin was added to the starch solution and stirred for 1 min to remove the NaOAc. The starch solution was filtered through a Millipore 0.45 μm pore size filter fitted to a 3 ml syringe. The filtered samples were injected in the HPLC with the SEC or GPC column. DP optimization of toothed starch chains in different dosages of glucanotransferase (GT) during 24 hr reactions (80 ° C, pH 5.7): Four different dosages of GT were tested: 1.25, 2.5, 5, and 10 ml / 100 g of starch. Surprisingly, more than the dosages in the DP values occurred in the first 4 hr, and the final DP values are different at different dosages.

Figure 10 shows the percentage of changes DP 37-100 at the four dosages after 24 hr. The components of DP 37-100 are desirable for the resistant starch, and greatly increased in the first 4 hr of reaction. At high dosage (10 ml / 100 g of starch), there was reduction of DP 37-100 after 6 hr of reaction. At the dosage of 5 ml / 100 g of starch, there was a reduction in DP 37-100 after 22 hr reaction. Figure 11 shows the percentage of changes of DP 25-100 in the four dosages during 24 hr. The pattern change pattern is exactly the same for DP 37-100. DP 25-37 components may be desirable for resistant starch with less heat stability, and it increases greatly in the first 4 hours of reaction. At high dosage (10 ml / 100 g of starch), there were decreases of DP 25-100 after 6 h of reaction. At the dosage of 5 ml / 100 g of starch, there was a decrease in DP 37-60 after 22 hr reaction. Figures 12 and 13 show the percentage of changes of DP 1-24 and DP 1-12 at the four dosages for 24 hr. The components of DP 1-24, especially DP 1-12, are undesirable for the resistant starch, and decreased greatly in the first 4 hr of reaction. At high dosage (10 ml / 100 g of starch), there was a decrease in DP 1-24 after 6 h of reaction.

Figure 14 shows the percentage of DP changes 100+ at the four dosages for 24 hr. DP 100+ components are undesirable for resistant starch, and decreased greatly in the first 4 hr of reaction. Figure 15 shows the best peaks of DP during 24 hr reaction to five different dosages of GT. The best DP peak during 24 hr correlates directly with the dosage of the GT enzyme. An increase in the reaction time at a low concentration of the GT enzyme did not give a high DP peak as a high concentration of the GT enzyme. Effects of high dosages of glucanotransferase (GT) on DP of branched chains: In previous studies, it was found that with the increase of enzyme dosages (from 1.25 to 10 ml / 100 g of starch), the DP of the final product is increased. In this experiment, the inventors tried to find that DP enzyme dosage of the final product would not increase with the increase of GT or the plateau of the DP graph with GT concentration. A 15% starch solution was added with 10, 12.5 and 15 ml of GT / 100 g of starch and the reactions were conducted at 80 ° C, pH 7.5. Samples were taken in 2, 4, 6, and 22 hrs. The results are shown in Figs. 16-21.

The increase of GT dosage from 10 to 15 ml / 100 g of starch gave some benefit, but the increase in the percentage of DP 37-100, and the reductions of DP 1-24 and 100+ were less compared with those observed when dosages of enzymes were increased from 1.25 to 10 ml / 100 g of starch. EXAMPLE 11 Treatment of Toothed Starch with GT Enzyme: Pearl-C Serrated Starch (DS 89.56%) was weighed (502.5 g), and 2497.5 g of water D.l. and 135 mg of CaCl2.2H20 were added to the starch (15% starch suspension). The pH of the starch suspension was adjusted to 5.5 using a 2N NaOH solution. The starch suspension was fired (285-290 ° F, 140-143 ° C), and usually the dry solids decreased from 15% to 13.19%. The pH was adjusted to 5.7 if it was different. 550 g of starch suspension were weighed in each of the various 1000 ml reactors. The GT enzyme was added according to the amount of dry solids in each of the various reactors. The GT starch mixture was incubated in a water bath at 80 ° C until hr. The samples (about 5 ml) were removed to analyze the length of branching chain. De-branching of the converted starch with GT: A sample converted with wet GT (approximately 13% solids) was heated with the hermetic lid in microwave at full power until it became a fluid. The samples (192125 mg) were weighed into 10 ml tubes, and 2.5 ml of purified water (HPLC grade) was added. For a dry sample, 25 mg of dry starch was weighed to be dissolved in 2.5 ml of purified HPLC grade water. The starch was solubilized in solution (approximately 1% solid) by microwaves. The solution of hot starch in hot potable water (approximately 50 ° C), and 50 μl of isoamylase [10 mg / ml isoamylase (1,280,000 U / g solid) in 0.1N NaOAc buffer, pH 4.5] was added to the solution. starch solution. The mixture of starch and isoamylase was incubated in an oven at 55 ° C for 2 hr. The mixture of starch and isoamylase was heated above 100 ° C to inactivate the isoamylase. The starch solution was cooled using hot potable water (approximately 50 ° C), and 0.1 g of Dowex MR-3 resin was added to the starch solution and stirred for 1 min to remove the NaOAc. The starch solution was filtered through a Millipore 0.45 μm pore size filter fitted to a 3 ml syringe. The filtered samples were injected in the HPLC with the SEC or GPC column. De-branching of converted starch with GT in DMSO solution: The debranching of the converted starch with GT in an experiment in which maltodextrin STAR-DRI 10 was added was conducted in DMSO solution. Dry starch (35 mg) was dissolved in 1 ml of aqueous DMSO (DMSO: water = 9: 1 v / v) or wet samples (269 mg, 13% of DS in samples converted with GT) are dissolved in 0.9 ml of pure DMSO. The starch solution was heated in a boiling water bath with stirring for 3 hr. The starch solution was then cooled to 39 ° C, and 3.5 ml of hot sodium acetate buffer (39 ° C, 50 mM) was added. 100 μl of isoamylase [10 mg / ml isoamylase (1,280,000 U / g solid) in 0.1N NaOAc buffer, pH 4.5] was added to the starch solution. The mixture of starch and isoamylase was incubated in a water bath at 39 ° C for 2 hr. The mixture of starch and isoamylase was heated in boiling water for 20 min, and then cooled to below 39 ° C. 100 μl isoamylase was added and the mixture was incubated for 16 hr. After debranching, the starch solution was heated in a boiling water bath for 20 min, and cooled to the hot temperature. A 2 mL aliquot of the mixture is diluted with 2 mL of pure DMSO. The DMSO mixtures (approximately 5 mg starch / ml) were heated in a boiling water bath for 20 min, allowed to cool to hot temperature. Dowex resin MR-3 (0.5) g was added to the starch solution and stirred for 1 min to remove the NaOAc. The starch solution was filtered through a Millipore 0.45 μm pore size filter fitted to a 3 ml syringe. The filtered samples were injected in the HPLC with the SEC or GPC column. Glucanotransferase (GT) Activity at Different Reaction Temperatures (75, 80, and 85 ° C): In this experiment, a 15% starch solution with 5 ml of GT / 100 g of starch was reacted at 75, 80 and 85 ° C, and the samples were taken at 1, 2, 4, 6, 8, 10 and 22 hrs after the addition of GT. The results are shown in Figs. 22-23. For a short reaction time (6 hr or less), the converted starch with GT had a higher ratio of DP 37-100 at a high reaction temperature (85 ° C). However, for a long reaction time (8 hr or longer), the converted starch with GT had a higher proportion of DP 37-100 at lower temperatures (75 and 80 ° C). As shown in Figs. 24-26, for a reaction time (6 hr or less), the starch converted with GT had a lower ratio of DP 1-24 or 1-12 at a high reaction temperature (85 ° C). However, for a long reaction time (8 hr or longer), the converted starch with GT had a lower proportion of DP 1-24 or 1-12 at lower temperatures (75 and 80 ° C). As shown in Fig. 6, for a short reaction time (6 hr or less), the trend was not clear for DP 100+ fraction. For a long reaction time (8 hr or longer) the converted starch with GT had a lower ratio of DP 100+ at higher temperature (80 and 85 ° C). It is likely that a higher temperature, less than the retrogradation occurred and the GT enzyme could work in the DP 100+ fraction more efficiently. Activity of Glucanotransferase (GT) at High Temperature: In a previous reaction temperature study (75, 80 and 85 ° C), the highest percentages of DP 37-100 were similar (close to 29%) in three different temperatures but the highest percentages of DP 37-100 were early at 85 ° C and late at 80 and 75 ° C. There was a detrimental effect (decrease in DP) if the reaction lasted longer than the optimal one (peak higher DP or DP higher "37-100"). An experiment was performed 1) for the DP 37-100 and the peak DP in the early stage (0.5 hr) at higher temperature, and 2) to test the heat stability of GT by pre-heating the GT enzyme to 85 ° C for 4 hr. In this experiment, the GT lOml / 100 g of starch was used in all four treatments. The reactions with GT with the starch were conducted at 80 ° C, 85 ° C, 85 ° C with GT converted with pre-heating (85 ° C for 4 hr), and 90 ° C. Figure 28 shows the results. In the first 1.5 hr, the percentage of DP 37-100 was higher at 95 ° C. However, the pre-heating of GT at 85 ° C gave a DP 37-100 more can than the GT reactions at 85 ° C. The fraction of DP 25-100 (Figure 29) followed a similar trend. The results considering the short DP chains (DP 1-12 and 1-24) were inconclusive due to the variation of the data but no significant detrimental effect was observed at higher temperatures (Figures 30 and 31). The peak DP (Figure 30) showed that the reaction at 90 ° C and a DP peak higher than the reaction at 80 ° C for 1.5 hr, and a preheating of GT at 85 ° C for 4 hr gave a peak DP higher than the reaction at 85 ° without preheated GT. Figure 32 shows that DP 100+ was lower at 90 ° C. Figure 33 shows that the peak DP was higher at 90 ° C over the first 1.5 hr, although the trend was not very clear. The DP peak for the reaction in longer times (from 2 hr to 8 hr) is shown in Figure 34. During a 2 hr reaction, lower temperature reactions are observed that are better than the higher temperature reactions for peak DP. Effect of the Addition of STAR-DRI 10 in Starch Converted with GT: Pearl-C Serrated Starch (15%) was fired jet (285-290 ° F), and the pH was adjusted to 5.7. STAR-DRI 10 maltodextrin was dissolved in DI water in a 1: 2 ratio, solubilized at 80 ° C, and adjusted to pH 5.7. The starch suspension was incubated at 80 ° C and four tests were conducted: 1. Suspension of starch + 10 ml of GT / 100 g of starch; 2. Suspension starch + 10 ml of GT / 100 g of starch + STAR-DRI 10 to 25% based on the dry starch; 3. Suspension of starch + 10 ml of GT / 100 g of starch and reaction for 2 hr, then STAR-DRI 10 to 25%; 4. Suspension of starch + 12.5 ml of GT / 100 g of starch + STAR-DRI 10 to 25%. Samples were removed in 2, 4, and 6 hr. The samples were debranched. The results are shown in Figs. 35-38. The addition of STAR-DRI 10 decreased the DP in the toothed starch converted with GT. This decreased overall DP, if STAR-DRI 10 was added at the beginning or after 2 hr of reaction. If the total DP still decreased if a comparable amount of the GT enzyme was added to compensate for the increase of the starch solids in the solution. Example 12 Treatment of GT-Enzyme Serrated Starch: Pearl-C Serrated Starch (DS 89.56%) was weighed (502.5 g), and 2497.5 g of water D.l. and 135 mg of CaCl2.2H20 were added to the starch (15% starch suspension). The pH of the starch suspension was adjusted to 5.5 using the 2N NaOH solution. The starch suspension was fired (285-290 ° F, 140-143 ° C), and usually the dry solids decreased from 15% to 13.19%. The pH was adjusted to 5.7 if it was different. 550 g of starch suspension were weighed in each of the various 1000 ml reactors. The GT enzyme was added according to the amount of dry solids in each of the reactors. The mixture of starch and GT enzyme was incubated in a water bath at 80 ° C for 24 hr. Samples (approximately 5 ml) were removed to analyze the length of branching chain. De-branching of converted starch with G: A sample converted with wet GT (approximately 13% solid) was heated in a test tube with a tight lid in a microwave oven at full power until it became a fluid. The samples (192 + 25 mg) were weighed in 10 ml tubes, and 2.5 ml of purified water (HPLC grade) was added. For a dry sample, 25 mg of dry starch was weighed to be dissolved in 2.5 ml of purified HPLC grade water. The starch was solubilized in solution (approximately 1% solid) by microwaves. The solution of hot starch cooled in hot water (approximately 50 ° C), and 50 μl of isoamylase [10 mg / ml isoamylase (1,280,000 U / g solid) in 0.1N NaOAc buffer, pH 4.5] was added to the starch solution. The mixture of starch and isoamylase was incubated in an oven at 55 ° C for 2 hr. The mixture of starch and isoamylase was heated above 100 ° C to inactivate the isoamylase. The starch solution was cooled using hot potable water (approximately 50 °), and 0.1 g of Dowex MR-3 resin was added to the starch solution and stirred for 1 min to remove the NaOAc. The starch solution was filtered through a Millipore filter of 0.45 μm pore size fitted to a 3 ml syringe. The filtered samples were injected in the HPLC with the SEC or GPC column. From the previous experiments, the best DP peak during 24 hr was directly correlated with the GT enzyme dosage. An increase in reaction time at low concentrations of GT enzyme did not give a high-type DP as did the concentrations of the GT enzyme. It is hypothesized that either the GT enzyme is inactivated after the first four hours of reaction or the starch is retrograded so that GT can not work effectively on the starch. To determine which factor was stopping the reaction, three experiments were performed: 1. GT was added directly after the jet cooking (0 hr) in full dosage (7.5 ml / 100 g of starch); 2. GT was added after the jet cooking in 1/3 of the total dosage (2.5 ml / 100 g of starch in 0 hr), the second dosage 1/3 (2.5 ml / 100 g of starch) after the 2.5 hr reaction and the third 1/3 dosage (2.5 ml / 100 g of starch) after the reaction in 4 hr; 3. GT was added after the starch was incubated at 80 ° C for 5.5 hr after jet cooking.

The experiment was proposed to reveal the stability of the GT enzyme at 80 ° C and the retrogradation effect of the starch on the activity of the enzyme. If the retrogradation of the starch had no effect on the activity of the enzyme and the enzyme is stable, then the final product (GPC profiles of debranched starch) would be the same after the extended enzyme reaction. Also, with each addition of GT enzyme (2.5 ml / 100 g of starch, three times), the GPC profiles of the debranched starch would change until they reach the same profiles as a full dosage (7.5 ml / 100 g of starch). The results are shown in Figs. 39-40. Figure 39 shows that the percentage of DP 37-100 was the same with the same dosage of GT (7.5 ml / 100 g of starch) after 4 h of reaction without considering whether the GT was added directly after the jet cooking (0 hr) or after the starch was incubated at 80 ° C for 5.5 hr. The same trend was real for DP 25-100. The DP 25-37 included may be desirable for the resistant starch but with less heat stability. When 1/3 of the total dosage of GT was added directly after the jet cooking (2.5 ml / 100 g of starch at 0 hr), DP 37-100 was increased in the initial 1.5 hr and then decreased from 1.5 hr to 2.5 hr. With the second addition of GT (2.5 ml / 100 g of starch), DP 37-100 increased rapidly. When the third dosage of GT (2.5 ml / 100 g of starch) was added, the change was not as great as with the addition of the second dosage. It is hypothesized that either retrogradation occurred after the reaction with the addition of the second GT dosage or the reaction was close to equilibrium after the reaction with the second GT dosage. More DP 37-100 material was obtained when GT was added in 1/3 dosing at a time than when it was added in a single dosage. Figures 41 and 42 show that the percentage of DP 1-24 and 1-12 were slightly higher when GT was added directly after the jet cooking (0 hr) than after the starch had been incubated at 80 ° C for 5.5 hr. However, the difference was less than 2%. When GT was added directly after jet cooking in 1/3 of dosing (2.5 ml / 100 g of starch at 0 hr), DP 1-24 decreased from 0 to 1 hr but increased from 1 to 3 hr, decreased quickly by adding the second dosage of GT, and then continuing to decrease with the third dosage of GT. There was less than DP 1-24 when GT was added in 1/3 dosing at one time instead of a full dosing. Figure 43 shows that DP 100+ descended rapidly and was close to the final value after the initial 2 hr enzyme reaction. It is surprising that although the low dosage of GT (2.5 ml / 100 g of starch) was added, DP 100+ decreased to a similar final value as with the high dosage (7.5 ml / 100 g of starch) after the reaction of 2. hr. It was also unexpected that DP 100+ was increased to approximately 0.5% to 4% with the second addition of GT (2.5 ml / 100 g of starch). Figure 43 also shows that the incubation of the starch suspension at 80 ° C for 5.5 hr after jet cooking and a higher final value of DP 100+. It is logical to conclude that some amylose was retrograde at 80 ° C during 5.5, and that GT can not work on these retrograde amylases. More data (every 0.5 hr) were obtained from the reaction when GT was added in 1/3 of the dosage at one time. The changes of DP detailed in the 8 hr reaction are shown in Figure 44. The DPs with the best peak of the GT enzyme (7.5 ml / 100 g of starch) converted the starch where the same with the same dosage of GT (7.5 ml / 100 g of starch) after 6 hr of reaction, without considering whether the GT was added directly after the jet cooking (0 hr) or after the starch was incubated at 80 ° C for 5.5 hr. (See Fig. 45). When GT was added in 1/3 of the total dosage in one time (2.5 ml / 100 g of starch in 0, 2.5, and 4 hr respectively), the DP of best peak increased progressively. The DP of best final peak, after the complete dosage (7.5 ml / 100 g of starch) was added, was better than the addition of the complete dosage in a time. Example 13. Resistant starch prepared according to the present invention was used to replace 51.7% of the flour in a cookie baking test (American Association of Cereal Chemists (AACC) test 53-10). The resistant starch was passed through a 40 US mesh screen and collected on a 200 US mesh screen, with the fine products passing through the 200 mesh screen. The average particle size was 202.5 μm and the mode was 185.4 μm. As analyzed by the AACC 56-11 test, the starch sample was found to be higher in water containment capacity than bakery flour, however, this measurement does not take into account what happens to the ingredients during the cycle of heating a cookie during baking. Table 4 Water Containment (AACC 56-11, sodium carbonate solvent only) An Instron tester was used to measure the firmness and tackiness of the dough. (Instron Corp., Canton, MA; inch ball probe; activating force = 10 g; pre-test speed = 5 mm / s; Test speed = 2 mm / s; Post test speed = 10 mm / s; penetration distance = 15 mm). 150 grams of dough were weighed on a tray that had a height of 8.4 cm, a width of 3.2 cm, and a length of 10.2 cm. The mass was compressed in the tray with a single actuation of a roller pin. The average values of at least three compressions were recorded. If a resistant starch imbibes excessive water, the dough becomes firm. The starch sample used in this experiment produced a mass that was less than firm (lower maximum load) than confectionery flour and was found to be less sticky as measured by force to release the probe after compression (min. ). Table 5 Performance of the Cookie Dough as Measured by Instron According to the AOAC (Association of Official Analytical Chemists) method 991.43, 71.94% of fiber was present in the resistant starch ingredient before baking, and 88.3% of that material was calculated as fiber after baking of the cookie. Table 6 Table 7 The height of the cookie for the control pastry flour cookie was greater than the height of the cookie that contained resistant starch. Additionally, the scatter of the cookie (width) was smaller for the control and larger for the cookie that has resistant starch. The larger dispersion and the reduced height is due to the property of low water containment of the resistant starch and indicates that the resistant starch was not hydrated or partially gelatinized during the filling process, but remained relatively unchanged. Table 8 Performance of the Cookie The foregoing description of specific embodiments of the invention is not intended to be a list of each possible embodiment of the invention. Persons skilled in the art will recognize that other embodiments would be within the scope of the following claims.

Claims (52)

1. CLAIMS 1. A process for producing a starch, characterized in that it comprises: treating a feed starch comprising amylopectin with glucanotransferase to produce an extended starch in the chain; and treating the extended starch in the chain with a debranching enzyme to produce a starch product comprising fragments of amylose; wherein at least about 38% by weight of the amylose fragments has a degree of polymerization (DP) of at least about 35.
2. 2. The process according to claim 1, characterized in that it also comprises recovering the amylose fragments. .
3. 3. The process according to claim 1, characterized in that the feed starch is toothed corn, waxy corn, potato, tapioca, rice, pea, wheat, waxy wheat or a combination of two or more thereof.
4. 4. The process in accordance with the claim 1, characterized in that the feed starch is treated with glucanotransferase in aqueous solution or suspension at a temperature of about 70-100 ° C and a pH of about 5.0 - 6.0.
5. 5. The process according to claim 1, characterized in that the debranching enzyme is isoamylase or pullulanase.
6. 6. The process according to claim 1, characterized in that the starch product has a polydispersity of about 2-4.
7. 7. The process according to claim 1, characterized in that it further comprises membrane filtering a solution or dispersion of the starch product to increase the concentration of amylose fragments having a degree of polymerization (DP) of at least about 35.
8. The process according to claim 1, characterized in that at least about 40% by weight of the amylose fragments have a degree of polymerization (DP) of at least about 35.
9. 9. The process according to the claim 7, characterized in that after membrane filtration at least about 70% by weight of the amylose fragments has a degree of polymerization (DP) of at least about 35.
10. 10. The process according to claim 1, characterized because the starch product has a peak melting temperature of greater than about 105 ° C.
11. 11. The process according to claim 1, characterized in that it further comprises heating the starch product in aqueous solution or suspension at a temperature of at least about 90 ° C.
12. 12. The process according to claim 11, characterized in that the starch product is heated in an aqueous solution or suspension at a temperature of at least about 98 ° C.
13. 13. The process according to claim 1, characterized in that the starch product is thermally stable is water at temperatures of up to at least about 90 ° C.
14. The process according to claim 13, characterized in that the starch product is thermally stable in water at temperatures of up to at least about 100 ° C.
15. The process according to claim 1, characterized in that the feed starch is a waxy starch, and wherein the process further comprises treating the feed starch with a debranching enzyme before the feed starch is treated with glucanotransferase. .
16. 16. The process according to claim 1, characterized in that the glucanotransferase is introduced in a dosage of approximately 1-15 ml per 100 grams of feed starch.
17. 17. The process according to claim 16, characterized in that the glucanotransferase is used in a dosage of about 5-12 ml per 100 grams of feed starch.
18. 18. The process in accordance with the claim 16, characterized in that the glucanotransferase is used in a plurality of dosages that are supplied to the feed starch of separate times.
19. 19. The process according to claim 1, characterized in that the feed starch is treated with glucanotransferase for a time less than about 8 hours.
20. 20. The process according to claim 19, characterized in that the feed starch is treated with glucanotransferase for a time less than about 6 hours.
21. 21. The process according to claim 1, characterized in that the re-branching enzyme is used in a dosage of about 1-10 mg per gram of starch.
22. 22. The process according to claim 21, characterized in that the debranching enzyme is used in a dosage of about 1-5 mg per gram of starch.
23. 23. A starch product, characterized in that it is produced by a process comprising: treating a feed starch comprising amylopectin with glucanotransferase to produce an extended starch in the chain; and treating the extended starch in the chain with a debranching enzyme to produce a starch product comprising fragments of amylose; wherein at least about 38% by weight of the amylose fragments has a degree of polymerization (DP) of at least about 35.
24. The starch product according to claim 23, characterized in that the process further comprises recovering the fragments of amylose.
25. 25. The starch product according to claim 23, characterized in that the feed starch is toothed corn, waxy corn, potato, tapioca, rice, pea, wheat, waxy wheat or a combination of two or more thereof.
26. 26. The starch product according to claim 23, characterized in that the feed starch is treated with glucanotransferase in aqueous solution or suspension at a temperature of about 70-100 ° C and a pH of about 5.0 - 6.0.
27. 27. The starch product according to claim 23, characterized in that the re-branching enzyme is isoamylase or pullulanase.
28. 28. The starch product according to claim 23, characterized in that the starch product has a polydispersity of about 2-4.
29. 29. The starch product according to claim 23, characterized in that the process further comprises membrane filtering a solution or dispersion of starch product to increase the concentration of amylose fragments having a degree of polymerization (DP) of less about 35.
30. 30. The starch product according to claim 23, characterized in that at least about 40% by weight of the amylose fragments have a degree of polymerization (DP) of at least about 35.
31. 31. The starch product according to claim 29, characterized in that after membrane filtration at least about 50% by weight of amylose fragment has a degree of polymerization (DP) of at least about 35.
32. 32. The product of starch according to claim 23, characterized in that the starch product has a peak melting temperature of about 105 ° C.
33. 33. The starch product according to claim 23, characterized in that the process further comprises heating the starch product in aqueous solution or suspension at a temperature of at least about 90 ° C.
34. 34. The starch product according to claim 33, characterized in that the starch product is heated in an aqueous solution or suspension at a temperature of at least about 98 ° C.
35. 35. The starch product according to claim 23, characterized in that the starch product is thermally stable in water at temperatures of up to at least about 90 ° C.
36. 36. The starch product according to claim 35, characterized in that the starch product is thermally stable in water at temperatures of up to at least about 100 ° C.
37. 37. The starch product according to claim 23, characterized in that the feed starch is a waxy starch, and wherein the process further comprises treating the feed starch with the debranching enzyme before the feed starch is treated. with glucanotransferase.
38. 38. A food product comprising a starch, characterized in that the starch is produced by a process comprising: treating a feed starch comprising amylopectin with glucanotransferase to produce an extended starch in the chain; and treating the extended starch in the chain with a debranching enzyme to produce a starch product comprising fragments of amylose; wherein at least about 38% by weight of the amylose fragments have a degree of polymerization (DP) of at least about 35.
39. 39. The food product according to claim 38, characterized in that the process further comprises recovering the amylose fragments.
40. 40. The food product according to claim 38, characterized in that the feed starch is toothed corn, waxy corn, potato, tapioca, rice, pea, wheat, waxy wheat or a combination of two or more thereof.
41. 41. The food product according to claim 38, characterized in that the feed starch is treated with glucanotransferase in aqueous solution or suspension at a temperature of about 70-100 ° C and a pH of about 5.0 - 6.0.
42. 42. The food product according to claim 38, characterized in that the re-branching enzyme is isoamylase or pullulanase.
43. 43. The food product according to claim 38, characterized in that the starch product has a polydispersity of about 2-4.
44. 44. The food product according to claim 38, characterized in that the process further comprises membrane filtering a solution or dispersion of starch product to increase the concentration of amylose fragments having a degree of polymerization (DP) of at least about 35.
45. 45. The feed product according to claim 38, characterized in that at least about 40% by weight of the amylose fragments have a degree of polymerization (DP) of at least about 35.
46. 46. The food product according to claim 44, characterized in that after membrane filtration at least about 50% by weight of the amylose fragments have a degree of polymerization (DP) of at least about 35.
47. 47. The food product according to with claim 38, characterized in that the starch product has a melting temperature pi co greater than about 105 ° C.
48. 48. The food product according to claim 38, characterized in that the process further comprises heating the starch product in aqueous solution or suspension at a temperature of at least about 90 ° C.
49. 49. The food product according to claim 48, characterized in that the starch product is heated in an aqueous solution or suspension at a temperature of at least about 98 ° C.
50. 50. The food product according to claim 38, characterized in that the starch product is thermally stable in water at temperatures of up to at least about 90 ° C.
51. 51. The food product according to claim 50, characterized in that the starch product is thermally stable in water at temperatures of up to at least about 100 ° C.
52. 52. The food product according to claim 38, characterized in that the feed starch is a waxy starch, and wherein the process further comprises treating the feed starch with the debranching enzyme before the feed starch is treated with glucanotransferase.