JP5429645B2 - Heat-inhibited starch and flour and process for its production - Google Patents

Description

  The present invention relates to heat-suppressed starch and flour and a method for producing the same. This heat-suppressed starch and flour can be used in place of the chemically cross-linked starch and flour currently used in food and in the manufacture of industrial products.

  The prior art teaches that starch can be heated for various purposes, for example, for drying, off-flavor evaporation, imparting a smoke flavor or dextrinization as shown by the following literature: Yes.

  Seidel et al., US Pat. No. 4,303,451, approved December 1, 1981, heats waxy maize starch at a natural pH in the range of 120-200 ° C. to remove woody odor and improve texture by alpha. Is disclosed.

  Japanese Publication No. 61-254602, December 11, 1986, discloses that waxy maize starch and waxy maize starch derivatives are heated at a temperature of 100 to 200 ° C. to provide starch having emulsifying properties instead of gum arabic. doing. In this step, starch is hydrolyzed by heating the starch in the presence of moisture, preferably under acidic conditions of pH 4.0 to 5.0, to obtain emulsifying properties.

  U.S. Pat. No. 4,303,452 discloses smoked treatment of waxy maize starch to increase gel strength and to impart a smoked flavor. In order to eliminate the smoke acidity and to obtain a final starch product having a pH of 4-7, the pH of the starch has been raised to a range of 9-11 prior to being smoked. The preferred moisture content of the starch in the smoke is 10-20%.

  Although these references disclose heating starch for various purposes, they can be inhibited in any way without the use of heating or chemical reagents to make the inhibited starch. There is no disclosure of how to make the starch.

  When natural starch granules are dispersed in water and heated, they hydrate and swell at about 60 ° C and reach a peak viscosity between the range of 65-95 ° C. This increase in viscosity is a desirable property in many food and industrial applications, and it results from physical attraction or frictional forces between highly swollen granules. However, swollen hydrated starch granules are quite brittle. If the starch slurry is kept at a temperature of 92-95 ° C, the starch granules begin to break and the viscosity begins to break down. Extreme pH shear conditions also tend to break up and break up the granules, which causes the starch polymer to dissociate and begin to melt, leading to a sudden drop from the original high viscosity.

  It is known that both starch granule swelling and viscosity reduction can be suppressed by treating starch with chemical reagents that introduce intermolecular crosslinks between starch molecules. This cross-linking reinforces the associative hydrogen bonds that bind the granules, suppresses the swelling of the starch granules, and consequently suppresses the collapse and fragmentation of the granules. Because of this suppression, cross-linked starch is also referred to as suppressed starch.

  Chemically cross-linked starch is used in many applications where a stable and viscous starch paste is required, so that no chemicals can be used so that natural or modified starch behaves equivalently to chemically cross-linked starch. If it can be controlled, it would be advantageous in reducing price, time and chemical use.

  The starches and flours of the present invention are heat-suppressed in a process that results in starches or flours having the characteristics of chemically cross-linked starch without the addition of chemical reagents. When these heat-inhibited starches and flours are dispersed in water at 92-95 ° C. and pH 3 as 5-6.3% anhydrous solids, they exhibit the characteristic properties of the inhibited starch: Perfectly suppressed starch and flour will resist gelatinization; highly controlled starch and flour will only gelatinize to a certain degree and will show a continuous increase in viscosity, but the peak Viscosity will not be reached; moderately suppressed starches and flours will show a lower peak viscosity and lower percent viscosity loss than the same unrestricted starch; and slightly Suppressed starch and flour will exhibit a slight peak viscosity increase and a lower percent viscosity decrease compared to control starch.

  In general, the heat suppression method dehydrates the granular starch or flour until it is anhydrous or substantially anhydrous (for the purposes of this specification, it means a moisture content of less than 1% by weight), then this Heat treating the anhydrous or substantially anhydrous starch or flour at a temperature and for a time effective to effect inhibition. Both the dehydration and heat treatment steps are performed under conditions that avoid the degradation or hydrolysis of the starch or flour.

  The starch or flour may be dehydrated and heated at its natural pH (generally in the range of pH 5.0 to pH 6.5), or the pH of the starch or flour may be increased from the beginning to neutral or higher.

  Neutral as used herein includes a range of pH values around pH and includes from about pH 6.5 to about pH 7.5.

  Preferably, the method raises the pH of the starch to above neutral, dehydrates the starch to anhydrous or substantially anhydrous, and the anhydrous or substantially anhydrous starch at a temperature of 100 ° C or higher. Heat treating for a time effective to provide the inhibited starch.

  By varying the process conditions, such as the initial pH of the starch or flour, the dehydration and heat treatment temperatures, and the heat treatment time, the level of inhibition can be varied to provide the various viscosity characteristics of the starch or flour. Since the parameters of the dehydration and heat treatment method can be correlated with the specific equipment used for dehydration and heat treatment, the choice of equipment will also be a factor in controlling the level of inhibition.

  In one embodiment, the dehydration and heat treatment steps are performed simultaneously. This process step may be carried out as part of a continuous process involving the extraction of starch or flour from plant material.

  The heat-suppressed starch and flour of the present invention are granules and can be derived from any natural source. These natural resources include banana, corn, pea, potato, sweet potato, burley, wheat, rice, sago, amaranth, tapioca, sorghum, waxy maize, waxy rice, waxy burley, waxy potato, waxy sorghum, starch with high amylose content It is possible. Suitable starches are waxy starches such as waxy maize, waxy rice, waxy potato, waxy saw gum and waxy burley. Unless specifically distinguished, references herein to starch are meant to include the corresponding flour. Reference to starch is meant to also include protein-containing starch, which is an endogenous protein or additional proteins from animal or plant resources, such as zein, albumin and soy protein.

  As used herein, natural starch refers to that found in nature. The starch may be natural starch or modified by enzyme, heat or acid conversion, oxidation, phosphorylation, etherification (especially hydroxyalkylation), esterification, and chemical crosslinking.

  In the first step of this process to achieve thermal inhibition, the starch is dehydrated for a time and at a temperature sufficient to make it anhydrous or substantially anhydrous. In the second stage, the anhydrous or substantially anhydrous starch is heat treated for a time and temperature sufficient to inhibit it.

  If the starch is left to heat in the presence of water, acid hydrolysis or degradation of the starch may occur. Hydrolysis or degradation will hinder or prevent inhibition. Therefore, the conditions for starch hydrolysis must be chosen so that inhibition will overcome hydrolysis or degradation. Any condition that meets this criterion can be used, but suitable conditions consist of raising the pH of the starch before dehydration at low temperature or before dehydration. This preferred condition consists of a combination of low temperature and neutral to basic pH.

  Preferably, the temperature at which the starch is dehydrated is kept below 125 ° C and more preferably at a temperature of 100-120 ° C or in that temperature range. The dehydration temperature may be less than 100 ° C, but temperatures above 100 ° C may be more effective in removing moisture.

  Suitable pH is 7 or more, generally pH 7.5 to 10.5, preferably 8 to 9.5, and most preferably greater than pH 8. It becomes easy to gelatinize at pH higher than 12. Therefore, pH adjustment at less than 12 is more effective.

For pH adjustment, the granular starch is slurried in water or other aqueous medium, generally in a ratio of 1.5 to 2.0 parts water to 1.0 part starch, and the pH is added to any suitable base To raise. A buffer, such as sodium phosphate, may be used to maintain the pH if necessary. The starch is then dehydrated and dried, or directly dried to a moisture content of 2-6%. Such a drying procedure is distinct from the stage of the thermal inhibition process that dehydrates the starch to an anhydrous state. Alternatively, a powdered starch may be sparged with a base solution until the starch reaches the desired pH, or an alkaline gas such as NH ₃ may be injected into the starch.

  For food applications, suitable food grade bases for use in the pH adjustment stage include, but are not limited to, sodium hydroxide, sodium carbonate, sodium pyrophosphate, ammonium orthophosphate, disodium orthophosphate, triphosphate. Contains sodium, calcium carbonate, calcium hydroxide, potassium carbonate and potassium hydroxide, and may include any other base approved for food use under the Food and Drug Administration Act or other food regulatory laws . Non-approved bases under these regulations may also be used provided that they are washed out of the starch and therefore the final product meets good manufacturing practices for food applications. A preferred food grade base is sodium carbonate. It should be noted that the texture and viscosity benefits of the heat suppression process tend to increase with higher pH, but higher pH tends to increase browning of the starch during the heat treatment process.

  If starch is not used for food, any effective or suitable inorganic or organic base that can increase the pH of the starch may be used.

  After dehydration, the starch is heat treated for a time and at a temperature or temperature range effective to inhibit it. A preferred heat range is a temperature or temperature range above 100 ° C. For practical purposes, the upper limit of the heat treatment temperature is usually around 200 ° C., and highly suppressed starch can be obtained at that temperature. Generally, the heat treatment is performed at 120 to 180 ° C, preferably 140 to 160 ° C, more preferably 160 ° C. The time and temperature profile will depend on the level of suppression desired.

  For most industrial applications, the dehydration and heat treatment steps are continuous and are accomplished by thermal application of starch starting from ambient temperature. In most cases, moisture will be expelled before the temperature reaches about 125 ° C. and the starch will be anhydrous or substantially anhydrous. If the starch reaches an anhydrous or substantially anhydrous state and heating continues, some level of inhibition will be achieved at the same time or even before the final heat treatment temperature is reached. Usually, at such an initial suppression level, the peak viscosity is higher than that achieved by a longer heat treatment time, however there will be a greater drop in viscosity from the peak viscosity. Continuing the heat treatment reduces the peak viscosity but reduces the viscosity drop.

  When moisture is present during the heat treatment step, and especially when the heat treatment step is carried out at an elevated temperature, the pH is adjusted above pH 8 to achieve inhibition.

  Starch resources, dehydration conditions, heating time and temperature, initial pH, and the presence or absence of moisture during the processing stage are all variables that affect the degree of inhibition that can be achieved. All of these factors are interrelated, and the tests of the examples show that various variables affect the control of the level of suppression, as well as the texture and viscosity characteristics of the suppressed product.

  These starches can be inhibited individually or several can be inhibited simultaneously. These starches may be inhibited in the presence of other materials or ingredients that do not interfere with the heat inhibition process or that alter the properties of the starch product.

  The process steps may be performed at normal pressure, vacuum or pressure and may be accomplished using any means known to those skilled in the art, however, suitable methods are suitable for dry heating in air or an inert aerobic environment. Depending on application.

  Following the heat treatment step, the starch may be screened to screen for the desired particle size, slurried in water and washed, filtered, then dried, or otherwise purified. The pH may be adjusted as desired. In particular, the pH may be readjusted to the native pH of the starch. The heat-inhibited starch may be pregelatinized to break up the granules after this heat-inhibiting step.

  This thermal inhibition step is another starch reaction that is used to modify starch for commercial use, such as heat or acid conversion, oxidation, phosphorylation, etherification (especially hydroxyalkylation), esterification and Can be used with chemical cross-linking. These modifications are usually done before the starch is heat-inhibited, but may be done after the fact.

  The dehydration and heat treatment equipment may be an industrial oven, such as a conventional oven, a microwave oven, a dextrinizer, a fluidized bed reactor and dryer, a mixer and blender with heating equipment, and other types of heaters, provided that The apparatus is required to have a vent to reach the atmosphere so that moisture does not accumulate and does not settle on the starch. Preferably, the device is equipped with a means for removing water vapor from the device, for example a vacuum device or blower for expelling air from the head space of the device, or a flowing gas is flowing. The heat treatment step may be accomplished in the same apparatus that performs the dehydration step and is most conveniently continued with the dehydration step. When the dehydration stage is continuous with the heat treatment stage, and especially when the dehydration and heat treatment apparatus is a fluidized bed reaction reactor or dryer, the dehydration stage occurs simultaneously with bringing the apparatus to the final heat treatment temperature.

  Excellent heat-inhibited starch with a high viscosity of zero or low percentage drop in viscosity is obtained in a fluidized bed reactor in a shorter time than can be achieved using other conventional heating ovens. . Suitable flowing gases are air and nitrogen. For safety reasons, it is preferable to use a gas containing less than 12% oxygen.

  Conventional ovens can be used to provide good heat-suppressed products that are acceptable for a wide range of applications. The temperature of the apparatus should be adjusted to 120-180 ° C, preferably 140-160 ° C, and most preferably about 160 ° C to obtain a heat-inhibited starch product. At a temperature of 160 ° C., the heating step is preferably performed for 3.5 to 4.5 hours. Depending on the precise temperature chosen, batch size, pH, choice of starch or flour used, and other factors, the heating step may be performed for about 1 to 20 hours.

In one particular embodiment, the non-viscous heat-stable starch is a natural granulated starch having a moisture content of 0-12% by weight, adjusted to a pH higher than 8.0 by the addition of a base, then 1 at 120-180 ° C. Made by heating process for ~ 20 hours. As stated earlier, moisture is driven off during this heating, and the heat treatment step is performed with anhydrous or substantially anhydrous starch or flour. On an industrial scale using a conventional oven, 4-5 hours of heating may be required to equilibrate the starch temperature to 160 ° C. before performing the heating step.
Texture inhibition characterization A starch or flour having a low to moderate degree of inhibition will exhibit certain texture properties when heated to disperse in an aqueous medium and gelatinize. In the examples below, these samples have been determined to be inhibited when the heated gelatinized slurry of the sample exhibits a tack-free and smooth texture.
Inhibition characterization by Brabender data Characterization of heat-inhibited starch is performed in detail by reference to its viscosity measurements after dispersion in water and gelatinization. The instrument used to measure the viscosity is Brabender VISCO / Amylo / GRAPH (manufactured by CW Brabender instruments, Inc., Hackensack, NJ). VISCO / Amylo / GRAPH records the torque it takes to balance the viscosity produced when the starch slurry is subjected to a programmed heating cycle. For uninhibited starch, the cycle typically begins with an increase in viscosity at about 60-70 ° C, the occurrence of a peak viscosity in the range of 65-95 ° C, and when the starch is kept at an elevated temperature, typically 92-95 ° C. It undergoes any viscosity reduction. This record consists of a curve that tracks viscosity through a heating cycle in arbitrary units of measurement expressed in Brabender units (BU).

Inhibited starch will exhibit a Brabender curve that is different from the curve with the same uninhibited starch (hereinafter control starch). At low levels of inhibition, the inhibited starch will reach a peak viscosity that is slightly higher than the peak viscosity of the control, and there will be no decrease in the percent decrease in viscosity relative to the control. As the degree of inhibition increases, the peak viscosity and viscosity drop decrease. At high levels of inhibition, the gelatinization rate and the swelling rate of the granules are reduced, the peak viscosity disappears, and when heated for a long time, the Brabender trace draws a rising curve, suggesting a slow continuous increase in viscosity. At very high levels of inhibition, the starch granules no longer gelatinize and the Brabender curve remains flat.
Sample Preparation All starches and flours used were granules, and unless otherwise noted, were provided by the National Starch and Chemical Company, Bridge Water, New Jersey.

  The control for the test sample was derived from the same natural resources as the test sample and was not modified or modified in the same way as the test sample and was at the same pH unless otherwise stated.

  All starches and flours of both test and control samples were individually prepared and tested.

  The pH of the sample is slurried starch or flour in water at 30-40% solids and then a sufficient amount of 5% sodium carbonate solution is added until the desired pH is reached.

  All samples were spray dried or flash dried (without thickening) to about 2-15% moisture as conventional in the art.

  The control sample was not further dehydrated or heat treated.

  The pH measurement of the sample before and after the thermal inhibition step was performed on a sample consisting of 1 part anhydrous starch or flour versus 4 parts water.

  Except when characterizing a conventional oven or dextrinizer, the test samples were dehydrated and heat treated in a fluidized bed reactor model No. FDR-100 manufactured by Procedyne Corporation, New Brunswick, NJ. The cross-sectional area of the fluidized bed reactor was 0.05 square meters. The starting layer height is 0.3-0.8 meters, but it is usually 0.77 meters. Unless otherwise noted, the flowing gas was air and was utilized at a speed of 5-15 m / min. The reactor sidewall was heated with hot oil and the flowing gas was heated with an electric heater. The sample was placed in the reactor and then either a flowing gas was introduced or a flowing gas was introduced. There was no difference between the samples in the loading order. The sample was brought from ambient temperature to 125 ° C. until anhydrous and further heated to a specific heat treatment temperature. When the treatment temperature was 160 ° C., the time to reach that temperature was within 3 hours.

  The moisture level of the sample at the final heating temperature was 0% unless otherwise specified. A portion of the sample was removed and tested for inhibition at the temperature and time indicated in the table.

These samples were tested for inhibition using the following Brabender procedure.
Brabender procedure Unless otherwise noted, the following Brabender procedure was used. All samples except corn, tapioca and waxy rice flour were slurried in a sufficient amount of distilled water to give a 5% solids anhydrous starch slurry. Corn, tapioca and waxy rice flour slurried at 6.3% anhydrous solids. The pH was adjusted to pH 3.0 with sodium citrate citrate buffer and the slurry was placed in a Brabender VISCO / Amylo / GRAPH sample cup with a 350 cm / g cartridge. The starch slurry was rapidly heated to 92 ° C. and held for 10 minutes. The peak viscosity and the viscosity after 10 minutes of the peak viscosity were recorded in Brabender units (BU). The percent viscosity reduction was calculated according to the following formula:

  “Peak” is the peak viscosity in Brabender units, and “(Peak + 10 ′)” is the viscosity in Brabender units 10 minutes after the peak viscosity.

  When the peak viscosity was not reached, ie when the data showed an ascending or flat curve, the viscosity at 92 ° C. and the viscosity 30 minutes after reaching 92 ° C. were recorded.

  Using the data from the Brabender curve, the inhibition was determined by dispersing the Brabender data during the Brabender heating cycle when dispersed at 92-95 ° C at pH 3 at 5 to 6.3% solids in water. (I) No increase in viscosity or almost no increase in viscosity (indicating that the starch was suppressed and did not gelatinize or resisted gelatinization); (ii) a continuously increasing viscosity with no peak viscosity (high starch (Iii) a lower peak viscosity and a lower percent viscosity reduction (indicating moderate inhibition) compared to the control; or (iv) a control Suppression was determined when there was a slight increase in peak viscosity and a lower percent decrease (indicating a low level of inhibition).

In the first three cases, the indicated moisture is the moisture in the starch before the dehydration and heat treatment steps. As noted above, starch becomes anhydrous or substantially anhydrous when it is brought from ambient temperature to heating temperature.
Example 1 This example illustrates the preparation of a starch of the present invention from commercially available granular waxy maize starch by the heat treatment process of the present invention.

  The process conditions and their effect on waxy maize starch viscosity and texture are shown in Tables I and II below.

To obtain a heat stable tack free thickener, a sample of granular starch is slurried in 1.5 parts of water and the pH of the slurry is adjusted by the addition of 5% Na ₃ CO ₃ solution, then the slurry Was stirred for 1 hour, then filtered, dried and ground. A dry starch sample (150 g) was placed in an aluminum foil pan (4 ″ × 5 ″ × 1.5 ″) and heated in a conventional oven under the conditions described in Tables I and II. The values indicated that the most heat stable starch was obtained by heating for about 3.5-6.0 hours at 160 ° C. and a pH of at least 8.0.

^a. All samples were commercial samples of granular waxy maize starch obtained from National Starch Chemical Company, Bridgewater, NJ.
^{b. The} unmodified control was a commercial granular waxy maize starch obtained from the National Starch Chemical Company of Bridgewater, NJ.
^{c. The} modification control was a commercial cross-linked (phosphorus oxychloride) granule waxy maize starch obtained from National Starch Chemical Company, Bridgewater, NJ.
^{d. The} sample was cooked by slurrying 7.0 g starch (water content 12%) in 91 ml water at neutral pH and then heating the starch slurry in a boiling water bath for 20 minutes.
^e. Low temperature evaluation was performed at 25 ° C.

^a. See Table I for sample details.
^{b. In the} Brabender procedure, a sample containing 5.4% solids anhydrous starch dispersed in water is rapidly heated to 50 ° C, then the heat is increased to 95 ° C at 1.5 ° C per minute, and Maintained at that temperature for 20 minutes.
Example 2 This example illustrates that various starches can be treated by the method of the present invention to provide a tack free thickener with properties similar to chemically cross-linked starch.

  Process conditions and their effects on the viscosity and texture of waxy burley, tapioca, V.O. hybrid and waxy rice starch are shown in Tables III and IV below.

^{a. The} tapioca starch sample was a commercial granular starch obtained from National Starch Chemical Company of Bridgewater, NJ. The waxy burley starch sample was a commercial granular starch obtained from Alko, Finland. The waxy rice starch sample was a commercially available granular starch obtained from Mitsubishi Corpoaition, Japan.
^b. Samples were slurried in 7.5 ml of 12% moisture content in 100 ml of water and then cooked by heating the starch slurry in a boiling water bath for 20 minutes.

^{a. The} VO hybrid starch sample was a granular starch obtained from National Starch Chemical Company, Bridgewater, NJ.
^{b. The} sample was cooked by slurrying 7.5 g starch with a 12% moisture content in 100 ml water and then heating the starch slurry in a boiling water bath for 20 minutes.

Viscosity and texture evaluation results show that a tack-free, heat-stable starch thickener can be prepared from waxy burley, VO hybrid, tapioca and waxy rice starch by the method of the present invention. The degree of inhibition (tack-free thickening properties in cooked aqueous dispersions) increased with increasing heat treatment time.
Example 3 This example illustrates the effect of temperature and pH and starch moisture content on the viscosity and texture of treated starch.
Part A:
A 20.4% moisture-containing waxy maize starch sample (100 g) was heated in an oven at 100 ° C. for 16 hours in a glass jar with a lid. Under the same conditions, the second sample was heated for 4 hours and the third sample was heated for 7 hours. The viscosity and texture of the product was compared with a 12.1% moisture granule waxy maize starch control using the cooking evaluation method of Table I of Example 1. The results are shown in Table V below.

^a. Samples were obtained from the National Starch Chemical Company, Bridgewater, New Jersey.
^{b. The} process was performed at pH 5.2.
^c. See Table III for cooking conditions.

These results indicated that the moisture added during this process resulted in a product that was as sticky and undesirable as the untreated control starch.
Part B:
A sample (900 g) of commercially available granular waxy maize starch (obtained from National Starch Chemical Company, Bridgewater, NJ) was placed in a 10 ″ × 15 ″ × 0.75 ″ aluminum tray and placed in an oven at 15, 30, 45 and Heated for 60 minutes at 180 ° C. The pH of the starch was not adjusted and remained at about 5.2 during the heating process The sample viscosity and texture were evaluated by the method of Example 1.

  As shown in Table VI below, the pH 5.2 sample was characterized by an undesirable sticky texture similar to that of the unheated waxy maize starch control.

^{a. The} pH is not adjusted from that of natural waxy maize starch (pH = 5.2) and Samples 1-4 correspond to starch treated by the process of US Pat. No. 4,303,451 (no pH adjustment).
^b. See Table III for cooking conditions.

  Thus, the combination of selected factors, including pH, moisture content and natural starch type, determines whether the desired non-sticky heat stable starch thickener can be produced by the method of the present invention.

The heat-inhibited starches and controls in the following examples are prepared as described above and are defined by texture characteristics or by correlating data obtained from Brabender curves using the procedure described above.
Example 4 Tapioca, Waxy Maize and Waxy Rice Flower: Characterization of Inhibition by Brabender Procedure
Samples of tapioca starch, waxy maize starch and waxy rice flour at pH 9.4 to 9.6 were dehydrated to a moisture content of less than 1% at temperatures below 125 ° C, equilibrated to 160 ° C and then heat reactor (horizontal double In a tank with a ribbon jacket). The sample heat treatment time was in the range of 3 to 6 hours.

  Samples were evaluated for inhibition according to the Bubender procedure above and the results are shown in the table below. Dehydrated and heated starches and flours showed a reduced viscosity compared to undehydrated and unheated controls. This inhibition correlates with a brittle, tack-free texture in the cooled product.

Example 5 Waxy Maize: Effect of Initial pH and Heating Time Initial pH and Heating Time on Levels of Inhibition on Natural pH (about 6.0) and Waxy Maize Starch Samples at pH 7.5, pH 8.5 and pH 9.5 And the data are shown in the table below. This data shows that starches with different levels of inhibition reflected by variations in the percent decrease in viscosity are obtained at different heating times and initial pH, and a high degree of inhibition is obtained at higher pH values and longer heating times. It can be done. Furthermore, when the shortened heat treatment time in this example using a fluidized bed reactor was compared to the heat treatment time in hours in Examples 4 and 5, a fluidized bed was used than would be possible with a standard thermal reactor or oven. It can be seen that an inhibited starch with a higher peak viscosity can be obtained in a much shorter time.

Example 6 Waxy Maze: Effect of heating temperature and time
The effect of heat treatment temperature and time on the level of inhibition on waxy maize starch at pH 9.5 was evaluated and the results are shown in the table below. This data shows that the inhibition samples are obtained at a heat treatment temperature of 100-200 ° C., and that further inhibition is obtained at higher temperatures or at longer times at lower temperatures. Starch samples heated at 200 ° C. were highly inhibited (up curve) or completely inhibited (not gelatinized).

Example 7 Waxy Maize: Effect of Moisture and pH Initial pH 9.5 waxy maize starch is evaluated for the suppression in the presence of 1-2 sample weight percent moisture by injecting saturated air into the fluidized bed reactor chamber. did. The results are shown in the table below, and show that starch heat-treated under anhydrous or substantially anhydrous conditions is more strongly inhibited than when heat-treated in the presence of moisture (for anhydrous samples). Note the low percentage of viscosity reduction).

Example 8 Corn Starch: Effect of pH and Heating Time at 160 ° C. Evaluate the effect of initial pH and heat treatment time at 160 ° C. on the inhibition level on samples of corn starch at natural pH and initial pH 9.5, The results are shown in the following table. This data shows that a very high level of inhibition is obtained at basic pH (note the increase in viscosity) compared to natural pH, and a stronger inhibition is obtained with longer heat treatment times.

Example 9 Potato Starch: Effect of pH The effect of initial pH on the level of inhibition on samples of potato starch at native and initial pH 9.5 was evaluated and the results are shown in the table below.

  Brabender data at natural pH suggested that starch degradation would occur with heat treatment rather than inhibition. This example shows that heat inhibition can be a function of both pH and starting starch. In this case, it was found that the thermal inhibition of potato starch is more dependent on pH than other starches (eg waxy maize). Therefore, the conditions necessary for potato starch dehydration and effective thermal inhibition are more stringent to avoid hydrolysis and degradation.

  However, dehydration and heat treatment in the basic pH range provided a suppressed starch that remained highly viscous, and heat treatment times longer than 90 minutes provided highly suppressed starch, as indicated by the continuing increase in viscosity. .

Example 10 Waxy maize with endogenous protein Effect of protein, time and temperature
Presence of protein against inhibition on samples of waxy maize containing 3.95% endogenous protein and adjusted to pH 8.5 and 9.5, and samples containing 1.52% endogenous protein and adjusted to pH 7.5 and 9.5, and heat treatment The effects of time and temperature were evaluated and the results are shown in the table below. This data indicated that the presence of the protein resulted in a level higher than that achieved with the protein-free sample. This result also shows that the protein level, pH and heat treatment time and temperature are all independent and have a cumulative inhibition level effect, and therefore, the inhibition increases with increasing protein, pH, time and temperature.

Example 11 Waxy maize substituted with propylene oxide:
Effect of etherification and pH Waxy maize samples reacted with 7 and 3 wt% propylene oxide at natural pH and pH 9.5 were evaluated for inhibition and the results are shown in the table below.

  This data shows that the substituted starch (in this case etherified starch) is thermally inhibited by this method and that higher inhibition can be achieved at higher pH.

  In addition to propylene oxide, other suitable etherifying agents known and utilized in the art can be used to etherify starch before and after thermal inhibition. Typical etherifying agents are acrolein, epichlorohydrin and combinations of epichlorohydrin and propylene oxide.

Example 12 Waxy maize substituted with an acetyl group:
Effect of esterification and pH Natural pH and pH 8.5 waxy maize samples reacted with 1% by weight of acetic anhydride were evaluated for inhibition and the results are shown in the table below.

  This data shows that substituted starch (in this case esterified starch) is inhibited to varying degrees and can be more strongly inhibited at higher pH.

  In addition to acetic anhydride, other common esterifying agents known and utilized in the art can be used to esterify starch before and after thermal inhibition. Typical esterifying agents include acetic anhydride, a combination of acetic anhydride and adipic anhydride, sodium orthophosphate, 1-octyl succinic anhydride, a combination of 1-octyl succinic anhydride and aluminum sulfate, phosphorus oxychloride. A combination of phosphorus oxychloride with either acetic anhydride or vinyl acetate, sodium trimetaphosphate, a combination of sodium trimetaphosphate and sodium tripolyphosphate, succinic anhydride and vinyl acetate.

Example 13 Waxy Maize Crosslinked with POCL ₃ :
Cross-linking and pH effects
Natural pH and pH 9.5 waxy maize samples crosslinked with POCL ₃ at 0.02% by weight were evaluated for inhibition and the results are shown in the table below. The data shows a falling viscosity, and increasing the heat treatment time almost eliminates the viscosity drop, suggesting that the cross-linked starch can be further suppressed by this method. This data also shows that inhibition increases further with increasing pH.

Example 14 Waxy Maize: Preparation of Starch pH in Fluidized Bed by Sprinkling NH ₃ on Fluid Gas N ₂
A waxy maize sample with an initial moisture content of 10.9% was introduced into a fluidized bed reactor with a nitrogen flowing gas containing ammonia at the concentrations shown in the table. These samples were evaluated for the effect of ammonia gas on the suppression level. By comparing the results with those obtained in Example 5 at pH 9.5, it can be seen that ammonia gas is effective in increasing the pH of the starch and inhibiting hydrolysis, but hydrolysis and inhibition. In the promotion of starch, direct pH adjustment of starch was not effective.

Example 15 Waxy Maize:
Adjusting pH in fluidized bed by sprinkling Na ₂ CO ₃ Waxy maize sample was introduced into fluidized bed reactor and 25% sodium carbonate solution was sprinkled at the same time as fluidized gas was introduced to raise pH . The sample was then raised from ambient temperature to 160 ° C. within 3 hours and held at 160 ° C. for the time indicated in the table.

  Samples were evaluated for inhibition. This data shows that this technique is effective in raising the pH of the sample to prevent acid hydrolysis and promote inhibition.

Example 16 Waxy Maze: Effect of Flowing Gas The pH 9.5 waxy maize sample flowed with nitrogen gas and air was evaluated for the effect of flowing gas on the suppression level. Samples were tested for inhibition and the data show that a higher inhibition rate is achieved when air is used as the flowing gas compared to nitrogen.

Example 17 Effect of High Amylose Content Samples of high amylose content starch (Hylon V) at natural pH and pH 9.5 were evaluated for the effect of high amylose content on inhibition. Due to the high level of amylose, it was necessary to use a pressurized visco / amylo / Graph (CWBrabender, Hackensack, NJ) to obtain a Brabender curve. The sample was slurried with 10% starch solids, heated to 120 ° C. and held for 30 minutes. This data indicates that inhibition was obtained only with the high pH sample.

Example 18 Waxy Maize and Tapioca: Substitution A sample of waxy maize and tapioca starch was slurried in 1.5 parts water. The slurry was placed in a 52 ° C. water bath, stirred and allowed to equilibrate for 1 hour. Concentrated HCl was added to 0.8% of the weight of the sample. The sample was converted at 52 ° C. for 1 hour. The pH was then adjusted to 5.5 with sodium carbonate and then adjusted to pH 8.5 with sodium hydroxide. The sample was collected by filtration and air dried (approximately 11% moisture). A 50 g quantity of starch was placed in an aluminum tray, covered, and placed in a forced draft oven at 140 ° C. for 5.5 hours. The starch was evaluated for inhibition and the results are shown in the table below and shown to be heat inhibited by this method of converted starch.

Example 18 Use of heat-inhibited waxy maize with natural pH in food This example includes heat-inhibited waxy maize starch (TI starch) with natural pH (pH 6) that has been heat-treated at 160 ° C. for 150 minutes. Describe the preparation of the barbecue sauce. The ingredients in weight percent are as follows:

The sauce was heated to 85 ° C, held for 15 minutes, and cooled to room temperature overnight. This sauce had a smooth and tack-free texture.
Application Description Granule heat-inhibited starch prepared by this method can be used in foods or industrial products using chemically cross-linked starch. The main advantage of these starches is that they have the inhibitory properties of chemically cross-linked starch without the use of chemical reagents. A further advantage is that these heat-inhibited starches and flours are substantially sterilized by a heat-inhibiting treatment and remain sterile when properly stored. It is also advantageous in that when a starch having natural linked dissolution stability is heat-inhibited by this method, the heat-inhibited starch remains frozen and melt-stable.

Claims (5)

Non-pregelatinized granular starch or flour heat-suppressed at a low level,
(A) dewatering the granular starch or flour to a moisture content of less than 1% by weight; and (b) maximizing the non-pregelatinized granular starch or flour with a moisture content of less than 1% by weight at temperatures above 100 ° C. Heat-treat for 20 hours;
A starch or flour produced by a process comprising the same, wherein the low level heat-inhibited starch or flour is the same starch or flour that is not heat-inhibited, ie a control starch or flour brabender Starch or flour showing a Brabender curve that is different from the curve, with the inhibitory starch showing a slight increase in peak viscosity and a lower percent decrease compared to the control.   The starch or flour according to claim 1, wherein the dehydration and heat treatment steps are carried out in a fluidized bed or in a dryer.   The starch or flour of Claim 1 or 2 whose said temperature is 120-180 degreeC.   The starch or flour according to any one of claims 1 to 3, wherein the dehydration and heat treatment steps are performed simultaneously. The starch or flour of any one of Claims 1-4 with which the said heat processing process is implemented for 1 to 20 hours.