WO1995004082A2

WO1995004082A2 - Heat treated noncohesive starches and flours and process for their production

Info

Publication number: WO1995004082A2
Application number: PCT/US1994/008559
Authority: WO
Inventors: Chung-Wai Chiu; Eleanor Schiermeyer; David J. Thomas; Manish B. Shah
Original assignee: National Starch And Chemical Investment Holding Corporation
Priority date: 1993-07-30
Filing date: 1994-07-29
Publication date: 1995-02-09
Also published as: WO1995004082A3; AU7552494A

Abstract

A process for making a heat treated, non-chemically modified, noncohesive starch or flour comprises the steps of providing a native, granular starch of a flour at a neutral or basic pH, dehydrating it to a moisture content of preferably less than 5 % by weight, and heating the starch or flour at greater than 100 °C for a period of time effective to obtain a product that is noncohesive when dispersed in an aqueous medium and gelatinized. The starch of flour is used in place of chemically cross-linked starches or flours.

Description

HEAT TREATED NONCOHESIVE STARCHES AND FLOURS AND PROCESS FOR THEIR PRODUCTION

This invention relates to a method for making noncohesive starch or flour (hereinafter "starch") from a native granular starch at a neutral or basic pH, dehydrated to a moisture content preferably less

than 5%, and then heated with sufficient dry heat for a time and at a

temperature effective to produce a starch inhibited from breakdown in viscosity and with noncohesive properties after gelatinization. The starch may be used in place of chemically modified or crosslinked starches presently used in foods, and in other applications, such as in the manufacture of paper and packaging.

The processed foods industry has sought to satisfy consumer demands for foods containing starches that have not been chemically modified but that have the same physical and functional properties as chemically modified starches. For example, starches are chemically modified with reagents, such as phosphorus oxychloride, sodium tri- meta-phosphate, adipic and acetic anhydrides and epichlorohydrin, to produce chemically crosslinked starches having excellent tolerance to processing variables such as heat, shear and extremes of pH. Such chemically crosslinked starches provide a desirable smooth texture to the processed food product and maintain their capacity for thickening throughout processing operations and storage of the food during normal shelf life. In contrast, unmodified starches are characterized by a breakdown in viscosity, loss of thickening capacity and textural qualities, and exhibit unpredictable behavior during shelf life as a result of the stresses applied during food processing. These stresses tend to fully disrupt the starch granule and disperse it into the food, permitting the starch molecules to be hydrolyzed by heat, shear and i extreme pHs, particularly acidic pHs, making the unmodified starches

unsuitable for use in processed foods.

The process of this invention is a heat treatment process that accomplishes the purposes of chemical modification of starches without use of typical chemical reagents. It also permits the food manufacturer to avoid label declarations associated with the chemical modification of starch, and, thereby, provide a perceived consumer benefit. Heat treatment of waxy maize starch at naturally occurring pH to remove woody flavors and modify texture on pregelatinization is

disclosed in U.S. Patent number 4,303,451, issued December 1, 1981, to Seidel, et al. The starch is heated with dry heat at a temperature within the range of 120° to 200°C to give consistently acceptable nonwoody flavor and improved texture in the pregelatinized starch.

Heat treatment of waxy corn starch and waxy corn starch derivatives to provide a starch with emulsification properties to replace gum arabic is disclosed in Japanese Patent Publication No. 61-

254602, published December 11, 1986. In this process, the starch is heated preferably under acidic conditions of pH 4.0-5.0 to hydrolyze the starch to obtain emulsification properties. The heating step is carried out at a temperature from 100° to 200°C with the optimum temperature being 130° to 150°C for 0.5 to 6 hours.

Smoke treatment of waxy corn starch to improve gel strength is disclosed in U.S. Patent number 4,303,452. In order to counteract the acidity of the smoke and to obtain a final starch product with a pH of 4 to 7, the pH of the starch is raised to a range of 9-11 before smoking. The preferred water content of the starch during the smoking is 10-20%.

There remains a need for starches that have noncohesive characteristics and that resemble chemically modified or crosslinked starches, that is, are stable to heat, pH and shear forces encountered in various industrial and food processing operations, such as, paper and corrugated paper board manufacturing, and retorting or pasteurizing canned or jarred foods. In particular, there is a need for a starch that does not contribute a cohesive character to processed food. It has now been discovered that such a starch may be prepared by the method of this invention. Summary of the Invention

This invention is a process for making a starch treated with heat that is the functional equivalent to a chemically crosslinked or modified starch. Initially, it should be noted that when certain native starches

(particularly waxy based starches) are gelatinized, they reach a peak viscosity, which soon begins to break down as that the starch polymers

dissociate and become solubilized, thereby causing the starch paste to become cohesive or runny. In contrast, when the starches made according to this process are dispersed in an aqueous medium and gelatinized, the starches have a viscosity more inhibited to breakdown

relative to starches that are not heat treated according to this process. The inhibition to breakdown correlates to what is subjectively a noncohesive, or "short" texture, meaning the gelatinized starch tends to be salve-like and heavy in viscosity rather than runny or gummy. The process comprises the steps: a) providing a native granular starch at neutral or basic pH; b) dehydrating the starch to a moisture content of 5% or less; and c) heating the dehydrated starch at a temperature of 100<>C or greater for a period of time effective to cause the starch to be noncohesive when it is dispersed in an aqueous medium and gelatinized, the heat treated starch being the functional

equivalent to a chemically crosslinked or modified starch. As used herein, "native" means a starch that has not been chemically crosslinked, modified, or treated in any way, and "heat treated starch" means a starch at neutral to basic pH heated with sufficient dry heat to provide a starch having functional characteristics

similar to those of a chemically crosslinked or modified starch.

The peak viscosity and viscosity breakdown of the heat treated

starches after gelatinization will vary depending on the processing

conditions (initial pH of the starch, moisture content of the starch during heating, heating temperature and time), and can vary over a broad range. Although the peak viscosity generally is lower than the peak viscosity of the same non-heat treated native starch, the viscosity will be stable, i.e. inhibited from breakdown. Breakdown, for purposes

herein, is measured as the difference between the peak viscosity and the viscosity at a specific time (usually 10 or 20 minutes) after peak viscosity under specific conditions when measured on a Brabender Viscoamylograph. For example, the peak viscosity of a heat treated waxy maize starch can be as high or greater than 600 Brabender Units with a breakdown of less than 100 Brabender units, measured at pH

3, 5.0% starch solids, and heated to 92°C. In this case, a breakdown

in starch viscosity of less than about 100 Brabender units correlates to a starch with a short, noncohesive texture, similar to the texture imparted by chemical crosslinking or modification. (Such starches, whether heat treated by the process of this invention or chemically treated, are termed inhibited.)

The preferred starting starches are native granular waxy maize, low temperature stable waxy maize hybrid ("V.O. hybrid"), waxy rice, waxy barley, tapioca, and potato. The process may be carried out as part of a continuous process including the extraction of the starch from a plant material. This invention also provides starches and flours prepared by the process herein, as well as food products comprising at least one starch or flour prepared by the method of this invention. The starches and flours useful in the process of this invention may be derived from any native source, including corn, pea, potato, sweet potato, barley, wheat, rice, sago, amaranth, tapioca, sorghum, waxy maize, waxy rice, waxy barley and the like. A suitable starch is described in U.S. Patent number 4,428,972, issued January 31, 1984, to Wurzburg, et al. Unless specifically distinguished, all references to starches herein include their corresponding flours. The conversion products derived from any of these native starches, including fluidity or thin-boiling starches prepared by oxidation, alpha-amylase conversion, mild acid hydrolysis or heat dextrinization, may be used. The converted starches may be prepared by any one of several methods that are well known in the art. See, e.g., M. W. Rutenberg, "Starch and Its Modifications" pages 22-36, Handbook of Water- Soluble Gums and Resins, R. L. Davidson, Editor, McGraw-Hill, Inc., New York, NY, 1980. Enzyme conversion of the starch may be carried out by the method disclosed in U.S. Patent No. 4,726,957 to Lacourse, et al. A combination of conversion techniques may be used. The conversion is typically carried out before the process of this invention,

but may be carried out afterwards. The converted base starch would

not be suitable for use in applications where a high viscosity starch is required.

While other starch modifications may be carried out on a granular native starch prior to the process of this invention, these

modifications (e.g., ether and ester derivatization) are not desired in applications where a food manufacturer requires a nonchemically modified product.

Providing a starch at a pH of neutral or above before the dehydration and heating steps is believed to reduce or eliminate the potential for any acid hydrolysis of the starch that may occur during those steps. Therefore, adjustment of the pH is preferably done before the dehydration step. However, if the dehydration conditions are not severe, pH adjustment may be done after the dehydration step, or both before and after.

Native granular starches typically have a pH of about 5.0 to 6.5. If the pH of the starch is naturally in the range of neutral or above, the starch may be dehydrated and heated without any initial adjustment of the pH. In cases where the pH of the starch is more acidic, the pH is raised to a level effective to maintain the pH at neutral or greater during the subsequent dehydration and heating steps. At pH levels above 12, gelatinization more easily occurs, and the practitioner must take that into consideration in choosing processing parameters.

In practice, the pH is raised to neutral or greater, preferably to 7.5 to 12, and most preferably to greater than 8.0 to less than 10.5 before the dehydration and heating steps. While a pH higher than the preferred range may be used, such a pH will tend to increase browning of the starch during the heat treatment. However, the noncohesive textural and viscosity benefits of the heat treatment process tend to be enhanced as the pH is increased. In selecting the precise pH at which the starch will be heated, the practitioner will select a balance between color formation and functional characteristics.

In a preferred embodiment the native starch is slurried in water (e.g., 1.5 to 2.0 parts of water to 1.0 part of starch) or an aqueous medium and the pH is raised by the addition of any suitable base. After the pH of the starch has been brought into the desired pH range, the starch slurry is either dewatered and then dried, or dried directly. These drying procedures are to be distinguished from the dehydration step in which the moisture content is brought to 5% or below. In another preferred pH adjustment step, a solution of a base may be sprayed onto the powdered starch. Buffers, such as sodium

phosphate, may be used to maintain pH, if needed.

For food applications a food grade base is used. Suitable food grade bases for use in the pH adjustment step of the process include,

but are not limited to, sodium hydroxide, sodium carbonate,

tetrasodium pyrophosphate, ammonium orthophosphate, disodium orthophosphate, trisodium phosphate, calcium carbonate, calcium hydroxide, potassium carbonate, and potassium hydroxide, together with any other base approved for food use under Food and Drug Administration laws and other food regulatory laws. Bases not approved for food use under these regulations may also be used, provided they can be washed from the starch so that the final product conforms to good manufacturing practices (GMP) for food use. The preferred food grade base is sodium carbonate.

If the starch is not going to be used for a food use, the base need not be a food grade base, and any workable or suitable inorganic or organic base that can raise the pH of starch may be used.

It has been found that starch subjected to the heating step with

a moisture content in excess of 15% results in a low viscosity product,

and may result in a cohesive texture when dispersed in an aqueous medium and gelatinized. In a preferred embodiment, the starch is dehydrated to a moisture content of 5% or less, more preferably 3% or less, and most preferably 1% or less, before the heating step. In the first stages of the heating, any residual moisture from the dehydration is quickly driven off, and heating occurs on the starch in an anhydrous state. Thus, as used herein, dehydration is intended to

mean the removal of moisture from the starch, and heating is intended to mean heating an anhydrous starch. Both the dehydration and heating steps contribute to the formation of a starch product that has noncohesive texture and stable viscosity. The dehydration can be accomplished in the same apparatus in which the heating step will occur, and most conveniently is continuous with the heating step. The dehydration and heating steps may be carried out in any apparatus fitted with a vent to the atmosphere such that moisture does not accumulate and precipitate onto the starch

during the heating process. The apparatus is preferably equipped with a means for removing water vapor from the apparatus (e.g., a vacuum or a blower to sweep air from the head-space of the apparatus, fluidizing gas) during the heating step.

Any industrial oven including, but not limited to, conventional

ovens, microwave ovens, dextrinizers, fluidized bed reactors and driers, mixers and blenders equipped with heating devices and other types of heaters, may be used in this step. Any combination of processing conditions is suitable provided that the starch product has characteristics of a chemically crosslinked starch, including a short, smooth, heavy, noncohesive texture devoid of any sticky, cohesive aspects when dispersed and cooked in an aqueous medium at about 0.1 to 35% solids.

The ideal time and temperature combination for the dehydration

and heating steps will depend upon the equipment used, and may also be affected by the type of native starch being treated, the pH and moisture content of the starch, and other factors identified and selected by the practitioner. For example, when a conventional oven or batch

dextrinizer is used, the dehydration step is carried out between 100°- 140°C, and the heating step between 100°-200°C, preferably 120°C- 180oC, more preferably 140° to 160°C, and most preferably about 160°C in order to obtain the heat treated starch product. At a temperature of 160°C, the heating step may be carried out for less than 5 hours. On an industrial scale, it may take 4 to 5 hours to equilibrate the starch temperature to 160°C prior to carrying out the heating step. Typically, shorter times will be required for higher temperatures and higher pHs. When the heating apparatus is a fluidized bed reactor or drier, the dehydration step occurs simultaneously while bringing the equipment up to the final heating temperature. A similar temperature profile may be used, but the product can be generated at a residence time of less than one hour at 160°C. It has also been discovered that

the use of the fluidized bed provides superior starches having higher

viscosities with less breakdown in viscosity, than could be achieved

with other conventional heating apparatuses.

Following the heating step, the starch may be screened to select a desirable particle size, slurried in water and washed, filtered, and dried, bleached, or otherwise refined. The pH may be adjusted (e.g., to pH 4 to 6). The starch may be blended with other unmodified or modified starches, including pregelatinized starches, or with food ingredients before use in a food product.

The starches prepared by this heat treatment process can be used in food products that are manufactured with a heat processing step, such as, pasteurization or retorting. The starches also may be used in other types of food products where a non-chemically crosslinked, noncohesive starch thickener is required. Based on

processed food formulations, the practitioner may readily select an amount of the starch product to provide the necessary viscosity and texture in the finished food product. However, the starch is preferably used at an amount of 0.1 to 35%, most preferably 2 to 6%, by weight,

of the food product. Among the food products that may be improved by the use of the starch product are baby foods, liquid infant formulations, heat

treated and canned or jarred sauces and gravies, soups, salad dressings and mayonnaise, yoghurt, sour cream and other dairy

products, pudding and pie fillings, liquid diet products and liquid products for hospital feeding. The starch products are also useful in

dry mixes for sauces, puddings, baby foods, hot cereals, and the like,

and are suitable for use in food applications where stability is required through all processing temperatures, including cooling, freezing and heating. For use in products subjected to temperature cycling operations, such as freeze-thaw cycling, a low temperature stable starch (e.g., waxy rice starch or flour or the "V.O." hybrid waxy maize

starch of U.S. Patent number 4,428,972) is preferred.

The heat treated starches of this invention are also useful in non-food applications where chemically crosslinked starches are known to be useful.

Screening examples, and representative processes for making the heat treated starches and using them in foods are illustrated in the

following examples. Screening Example 1

This example screens various processing conditions for their effects on viscosity and texture of waxy maize, waxy barley, tapioca, waxy rice, and V.O. hybrid starches. A sample of each granular starting starch was slurried in water, the pH of the slurry was adjusted with the addition of a 5% sodium carbonate solution, the slurry was agitated for 1 hour, then filtered and dried to less than 15% moisture content. The dry starch samples (150 g) were placed into an aluminum foil pan (4" x 5" x 1-1/2") in a conventional oven at 160°C to both dehydrate and heat the starch.

Brabender Evaluation of Waxy Maize. A sample of the heat treated waxy maize starch was slurried in water at neutral pH and 5.4% anhydrous solids, introduced to a Brabender Viscoamylograph for measurement of peak viscosity and breakdown, and heated rapidly to 50°C. The heat was increased by 1.5°C per minute to 95°C, and held for 20 minutes. The breakdown was measured as the difference between the peak viscosity and the viscosity after 20 minutes at 95°C. The samples were compared to a non-heat treated waxy maize control under the same Brabender evaluation conditions. The results given in Brabender Units (BU) are set out in Table I and show the production of an inhibited starch. This product is prepared by heat treating a 8.2 pH starch at 160°C for 4.5-5.5 hours. Table I Brabender Evaluation of Granular Waxy Maize Starch

Process Variables Brabender Viscosity

Sample pH of Heating Time Peak Break¬ the Temp. (Hours) Viscosity down at starch (°C) (B.U.) 95°C/20 before Mins. heating (B.U.)

3 8.2 160 3.5 985 155

4 8.2 160 4.0 805 120

5 8.2 160 4.5 640 5

6 8.2 160 5.5 575 5 naturally none none 1640 1010

Control occurring

(6.0)

1 (6.0) 160 2.0 1055 495

2 (6.0) 160 4.0 140 60

The remaining starches were screened subjectively for noncohesive properties and the results are set out in Table II. Waxy maize samples were gelatinized by slurrying 7.0 g of starch (at 12% moisture) in 91 mis water at neutral pH and heating the starch slurry for 20 minutes in a boiling water bath. Barley, tapioca, rice and V.O. hybrid samples were gelatinized by slurrying 7.5 g of starch (at 12% moisture) in 100 mis water at neutral pH and heating the starch slurry for 20 minutes in a boiling water bath. Evaluation was done by observation when the cooked starches cooled to room temperature. The results show that noncohesive properties can be obtained by heat treating various starches at 160°C when the pH of the starch is not acidic.

Table II Processing Variables and Evaluation for Noncohesiveness of Various Starches

Process Variables

Cold Evaluation

Sample Heating (160°C) of Gelatinized

Samples at 25°C pH of Time (hrs) Texture the starch before heating

Waxy Maize⁸

Control, naturally not heated cohesive unmodified" occurring

Control, 6.0 not heated noncohesive chemically crosslinked⁰

1 6.0 2 cohesive

2 6.0 4 (thin viscosity)

3 8.2 3.5 cohesive

4 8.2 4 slightly cohesive

5 8.2 4.5 noncohesive

6 8.2 5.5 noncohesive

7 8.2 6 noncohesive Waxy Barley Starch^d

Control, naturally 0 cohesive unmodified occurring

1 8.7 1.5 cohesive

2 8.7 2.5 slightly cohesive

3 8.7 3.5 noncohesive

4 5.2 1.5 (thin viscosity)

5 5.2 2.5 (thin viscosity)

Tapioca Starch⁶

Control, naturally 0 cohesive unmodified occurring

6 8.8 2 cohesive

7 8.8 3 cohesive

8 8.8 4 slightly cohesive

9 8.8 5 noncohesive

10 5.5 3 (thin viscosity)

Waxy Rice Starch^f

Control, naturally 0 cohesive unmodified occurring

1 9.1 2 cohesive

2 9.1 3 slightly cohesive

3 9.1 4 slightly cohesive

4 9.1 5 noncohesive

V.O. Hybrid Starch⁹

Control 5.9 0 cohesive

1 8.7 2.0 cohesive 2 8.7 3.0 slightly cohesive

3 8.7 4.0 smooth cohesive

4 8.7 5.0 noncohesive

5 8.7 6.0 noncohesive

Waxy maize starch samples were commercial samples of granular waxy maize starch obtained from National Starch and Chemical Company, Bridgewater, New

Jersey.

10 The unmodified waxy maize control was a commercial granular waxy maize starch obtained from National Starch and

Chemical Company, Bridgewater, New

Jersey.

15 The modified waxy maize control was a commercial crosslinked, (phosphorous oxychloride treated) granular waxy maize starch obtained from National Starch and

Chemical Company, Bridgewater, New

20 Jersey.

Waxy barley starch samples were commercial granular starch obtained from

AIKo, Finland.

Tapioca starch samples were commercial

25 granular starch obtained from National

Starch and Chemical Company,

Bridgewater, New Jersey.

Waxy rice starch samples were commercial granular starch obtained from Mitsubishi

30 Corporation, Japan. g- V.O. hybrid starch samples were granular starches obtained from National Starch and

Chemical Company, Bridgewater, New

Jersey. Screening Example 2

This example illustrates the effect of starch moisture content

during heating on the viscosity and texture of the treated starch.

Three samples of waxy maize starch from National Starch and

Chemical Company, Bridgewater, New Jersey, (each 100 g) containing

20.4% moisture were heated in an oven at 100°C in a sealed glass jar.

Sample 1 was heated for 16 hours, sample 2 for 4 hours, and sample

3 for 7 hours. The product viscosity and texture were subjectively compared to a 12.1% moisture granular waxy maize starch control by observation after the gelatinization procedure of Example 1. The starch samples had a pH of 5.2; no pH adjustment was made. None of the samples became noncohesive, and they remained as cohesive as the control starches that had not been heat treated.

Screening Example 3 Samples of tapioca starch, waxy maize starch, and waxy rice flour were independently slurried in water, at 35% solids for the tapioca and waxy maize, and 30% solids for the waxy rice flour. The pH of each slurry was adjusted to between 9.4 to 9.6 with a 5% sodium carbonate solution. The pH adjusted slurry was then spray dried to 2-

3% moisture. A control sample for each of the starches was isolated from this batch and was not further dehydrated or heat treated.

Two samples, for each of the waxy maize and tapioca starches

and the waxy rice flour, were separated from the spray dried material. Each of these samples was dehydrated to less than 1% moisture at a temperature below 120°C, equilibrated to 160°C, and then heated at

160°C in a thermal reactor. The heating time for the samples ranged up to five hours.

Brabender Evaluation Method. The control and samples were independently slurried at 5.0% anhydrous solids and adjusted to pH

3.0. Each slurry was introduced to a Brabender Viscoamylograph, heated rapidly to 92°C and held for 20 minutes. The same procedure was performed for the tapioca and waxy rice controls and samples, except that these were slurried at 6.3% solids. The viscosity was measured on a Brabender Viscoamylograph and breakdown was measured as the difference between the peak viscosity and the viscosity 10 minutes after peak viscosity. The results are given in Brabender Units (BU).

Two viscosity and breakdown measurements were taken for the waxy maize starch and waxy rice flour samples, the second

measurement following the first by approximately one hour. The tapioca samples were from two independent batches. The data are recorded in Table III and show that heat treated starches are inhibited from breakdown of viscosity relative to native starches that were not heat treated. This inhibition correlated to a short, noncohesive texture in the cooled product.

Table III

Starch at pH Peak Breakdown

9.4-9.6 before Viscositv heating BU BU

Tapioca Control 1300 915

Heat 340 45 Treated

Heat 575 135 Treated

Waxy Maize Control 1135 730

Heat 640 25 Treated

Heat 580 20 Treated

Waxy Rice Control 1140 833 Flour

Heat 695 10 Treated

Heat 600 10 Treated

Example 4

Samples of waxy maize starch and tapioca starch were heat treated and evaluated for noncohesiveness. Two waxy maize samples were prepared, one at an initial pH of 9.5 and the second at an initial pH of 8.5. The tapioca sample was prepared at an initial pH of 9.5. Each sample was heated from ambient temperature to within the range of about 155°-165°C and held for less than three hours in a

conventional heating apparatus. Preparation of the pH adjusted starches was as follows:

A. Waxy Maize at DH 8.5. Waxy maize starch was slurried in water at 30-35% solids, and the pH of the slurry adjusted to 8.5 with a 5% solution of sodium carbonate. The slurry was filtered and flash dried to less than 8% moisture.

B. Waxy Maize at PH 9.5. Waxy maize starch was slurried in water at 30-35% solids, and the pH of the slurry adjusted to 9.5 with a 5% solution of sodium carbonate. The slurry was spray dried to less than 3% moisture.

C. Tapioca at pH 9.5. Tapioca starch was slurried in water at 30-35% solids, and the pH of the slurry adjusted to 9.5 with a 5% solution of sodium carbonate. The slurry was spray dried to less than 3% moisture.

D. Brabender Evaluation Method. A sample of each of the waxy maize starches slurried at 5.0% anhydrous solids and adjusted

to pH 3.0 was introduced to a Brabender Viscoamylograph. The slurry was heated rapidly to 92°C and held for 20 minutes. The same

procedure was performed for the tapioca sample, except that this was

slurried at 6.3% solids. The viscosity breakdown measured as the difference between the peak viscosity and the viscosity 10 minutes after peak viscosity were measured in Brabender Units on a Brabender Viscoamylograph. The data are recorded in Tables IV-VI and show that heat treated starches are inhibited from breakdown of viscosity relative to native starches that were not heat treated. This inhibition correlated to a short, noncohesive texture in the cooled product.

Table IV Waxy Maize at 8.5 pH

Heating Heating Peak Breakdown Time Temp. Viscosity BU Hours °C BU

12 163 560 70

12.75 163 540 65

11 162 530 75

10.25 168 530 70

10.25 163 510 75

Heating Time = Time required to dehydrate and heat the starch from ambient temperature (this includes the holding time at the final temperature).

Table V Waxy Maize at 9.5 pH

Heating Heating Peak Breakdown Time Temp. Viscosity BU Hours °C BU

10.25 155 605 40

11.0 162 530 30

9.25 160 540 30

10.0 162 470 55

9.5 166 440 25

Table VI Tapioca at 9.5 pH

Heatinq Heating Peak Breakdown Time Temp. Viscosity BU Hours °C BU

11.5 155 525 50

9.0 165 500 35

6.0 158 905 305

Heating Time = Time required to dehydrate and heat the starch from ambient temperature (this includes the holding time at the final temperature). Screening Example 5 Fluidized Bed Reactor

Samples of waxy maize starch at naturally occurring pH (about

6.0) and adjusted with sodium carbonate to pH 8.5 and to pH 9.5 were prepared, dehydrated to less than 1% moisture, and then heated at

160°C in a fluidized bed reactor. The starch was simultaneously

dehydrated and heated from ambient temperature to 160°C in less

than three hours and then held at 160°C for the time showed in Table

VII. Samples were evaluated for peak viscosity and inhibition to breakdown according to the Brabender evaluation method for the waxy maize samples in Example 4. The data are set out in Table VII and show that inhibited starches, with higher peak viscosities and less breakdown, can be obtained using the fluidized bed reactor compared to standard thermal reactors, and that these inhibited starches can be obtained at much shorter times than were possible with standard thermal reactors.

Table VII Waxy Maize Heated at 160°C

Initial Heating Time Peak Breakdown PH min Viscosity BU

BU

6.0 0 1053 593

30 710 250

60 645 200

90 570 130

120 560 120

150 485 90

7.5 90 550 200

120 470 145

150 415 120

180 380 100

8.5 0 980 350

30 770 115

60 665 40

90 625 25

120 585 5

9.5 0 1055 175

30 825 25

60 705 5

90 690 0

120 665 5 Screening Example 6

This example shows the effects of the heating temperature and

time on peak viscosity and inhibition for a waxy maize starch adjusted to pH 9.5 with a 5% solution of sodium carbonate. The peak viscosity

and breakdown were measured on a Brabender Viscoamylograph

according to the evaluation method of Example 4. The heating was

done in a fluidized bed reactor similarly to Example 5. The samples were taken when the temperatures were achieved as shown in Table VIII. The results are set out in Table VIII and indicate that noncohesive samples can be obtained at heating temperatures

between 100°-200°C, with more inhibition obtained at higher

temperatures or at longer times with lower temperatures.

Table VIII Time and Temperature Study

Heating Time at Heating Peak Breakdown Temp. Temperature Viscosity (BU)

110°C 22 hrs 1185 215

160°C 0 1055 175

160°C 120 min 665 5

175°C 0 850 95

180°C 0 715 35

190°C 0 555 5

200°C 0 rising curve^*

200°C 120 min no viscosity

* Peak not reached

Food Example 7

This example illustrates the use of the starches in a processed food product, a retorted white sauce.

Part A: A white sauce was prepared from the formulation set forth below by (1) blending the dry ingredients and adding them to the milk and water with a no- shear Baldor Mixer (a Lightin' Mixer type unit); (2) heating the mixture to 80°C; (3) adding the liquid margarine and blending for 15 minutes; and (4) filling 10 ounce cans with the mixture and heat processing the canned sauce to an internal can temperature of 121 °C (250°F) and a minimum Fo of 5 in a pilot scale, water immersion Stock 900 retort. White Sauce Formulation

Ingredient Percent by Weight

Whole Milk 45.74

Water 45.73

Liquid Margarine 5.00

Starch 2.20

Salt 0.73

Wheat Flour 0.50

White Pepper 0.05

Nutmeg 0.05

Total 100.00

The starches described in Table IX, below, were added to the white sauce and the sauces were tested prior to filling the cans and after retorting for viscosity (using a Brookfield RVT Viscometer with a #4 spindle at 10 rpm) and visually evaluated for texture and organoleptic quality. Results are shown in Table IX.

Table IX Heat-Treated Waxy Rice Starch In Retorted White Sauce

Starch³ Hot Fill Viscosity Description Relative

Viscosity after Rank"

(cps) Retorting (cps)

1^c 200 1600 slightly thin, no 8.5 lumps, slightly grainy

₂d 600 2800 smooth, no 9.0 lumps, creamy

3^e — 2000 slightly thin, a 8.5 few lumps, slightly grainy

4 (control) 500 2400 very slightly 8.0 grainy, slightly thin cross-linked 44 4400 grainy, thin, 7.0 waxy^f maize margarine starch separated'

(control)

Samples 1-3 are heat treated waxy rice starches. Sample 4 is the un-processed rice starch base used in the preparation of

Samples 1-3.

Represents organoleptic ranking of 1-10

(10=best) for visual appearance and texture.

Sample 1 was heated at 160°C for 0.5 hours at a pH=8.5 and a moisture content of 10.6%. d. Sample 2 was heated at 160°C for 1.0 hours at a pH=8.5 and a moisture content of 10.6%.

Sample 3 was heated at 160°C for 2.0 hours at a pH=8.5 and a moisture content of 10.6%. f. The initial heat treatment prior to filling the cans was insufficient to gelatinize the chemically crosslinked starch control. Therefore margarine separation was observed and the hot fill viscosity was quite low.

Although less viscous than chemically modified starches when

used at the same percentage in the sauce formulation, the heat treated

waxy rice starches thickened the sauce throughout processing, gave excellent texture, and were comparable in quality to, or better than, commercial starches used in retorted white sauces.

Part B:

A white sauce was prepared as described in Part A, except whole milk (91.47%) was used in place of the whole milk (45.74%) and water (45.73%) mixture used in Part A.

The waxy maize starches and control starches described in Table X, below, were tested in the white sauce by the methods of Part

A. Results are shown in Table X. Table X Heat-Treated Waxy Maize Samples In Retorted White Sauce

Starch Processing White Sauce

Sample Heating Viscosity Description Relative

Time After Rank"

(hours) Retorting (cps)

1 5.5 2825 tan, small 8.0 lumps

_2b 4.5 4925 off-white, 8.0 lumpy, creamy, slightly better than sample 1

3^b 4.0 6600 off-white, 6.5 lumpy, thick, heavy

4^C 3.5 5200 some 7.0 lumps, slightly cohesive control- 4000 short, 7.5 chemically slightly cross¬ grainy, linked slight waxy margarine maize separation starch^d

Represents organoleptic ranking of 1-10

(10=best) for visual appearance and texture.

Samples 1-3 are waxy maize starch samples adjusted to a starting pH=8.5 with

5% Na₂C0₃ solution and heated at 160°C for 4.0 to 5.5 hours. Sample 4 is the sample of waxy maize starch identified as Sample 3, Table I,

Example 1 , above.

Control starch was a commercial product obtained from National Starch and

Chemical Company, Bridgewater, New

Jersey.

Although the results show a drop in viscosity in starch-

thickened, retorted white sauce as the starch process is continued

beyond 4.5 hours at a pH=8.5 for waxy maize starch, the relative ranking is acceptable. The starches were ranked as comparable to or better than the commercial, chemically crosslinked control in texture and organoleptic character.

Food Example 8

This example illustrates the use of heat treated waxy maize starch and waxy rice flour in a 25% fat salad dressing (mayonnaise type).

The salad dressing was prepared by (1) blending the dry ingredients; (2) preparing a potassium sorbate solution; (3) adding the dry mixture to an aqueous phase containing the potassium sorbate solution and other aqueous liquids; (4) heating to 85°C for 5 min.; (5) cooling to 30°C; (6) adding an egg and oil mixture under vacuum and homogenizing the two mixtures; and (7) filling into glass containers. 25% Fat Salad Dressing Formulation Ingredient % by Weight

Water 42.58

Sunflower oil 25.00 Fresh whole eggs 8.50

Sugar 7.50

Starch³ 4.50

Wine vinegar 3.50

Tarragon vinegar 3.50 Mustard 2.20

Salt 2.00

Lemon vinegar 0.50

Citric acid 0.20

Potassium sorbate 0.02 Total 100.00

a. The experimental starch and flour samples were adjusted for viscosity purposes to contain 5.00% starch. The control (a highly stabilized crosslinked chemically modified waxy maize starch) was used at 4.50% starch and the 0.5% difference was taken off the weight of the water.

Under relatively severe processing conditions (i.e., high shear) as well as the high acid (about pH 3.3) and fat content, both waxy maize starch and waxy rice flour gave excellent texture, creaminess,

and homogeneity. In addition, the taste of the experimental products was comparable to that of the control. Although lower in viscosity

compared to the control, the results of a short-term storage stability test revealed a stable product through at least 4 weeks of refrigerated storage. See Table XI, below for stability test results expressed as a function of viscosity in cps units (Brookfield RVT Viscometer, #4 spindle, 10 rpm).

Table XI

Storage Stability of Salad Dressings

Using Heat Treated Starch or Flour

Weeks of Control- Heat-Treated Heat-Treated

Refrigerated Chemically Waxy Maize Waxy Rice

Storage Modified Starch Flour Starch cps cps cps

0 21,500 13,500 10,250

1 17,250 12,250 8,500

2 17,000 11,750 8,250

3 18,000 11,500 9,000

4 17,250 11,500 9,250

Food Example 9

This example illustrates the use of the heat treated starches in baby food.

Part A: The heat treated starch is added to retorted plums using the following baby food formulation. The baby food is heated to 88°C (190°F), and held at 88°C for 10 minutes, placed in glass jars, sealed and retorted. The starch thickens the plums and gives them a noncohesive texture. Plums-Baby Food Formulation

Ingredient Percent bv Weight

Plums 23.00

Sugar 15.00

Corn Syrup 15.00

Starch 5.50

Water 51.50

Total 100.00

Part B: The heat treated starch is added to retorted cottage cheese

using the following baby food formulation.

Cottage Cheese Baby Food Formulation Ingredient Percent by Weight

Cottage Cheese 35.0

Water 13.0

Sugar 10.5

Starch 4.5

Pineapple Juice 4.0

Reconstituted Lemon Juice 2.3

Water 30.7

Total 100.0

The cottage cheese and 13% of the water are thoroughly blended. A slurry of the remaining ingredients is prepared and cooked

to 88 to 91 °C (190 to 195°F). The cottage cheese and water are slowly added to the cooked mixture with agitation and the temperature is brought to 88°C (190°F). The hot product is placed in jars, sealed and retorted for 20 minutes at 116°C (240°F). The heat treated starch thickens the cottage cheese baby food and gives it a noncohesive

texture.

Claims

We Claim:

1. A process for making a heat treated starch that is noncohesive when dispersed in an aqueous medium and gelatinized comprising the

steps: a) providing a native granular starch at a neutral or basic

pH; b) dehydrating the starch to a moisture content of 5% or less; and c) heating the dehydrated starch at a temperature of 100°C or greater for a period of time effective to cause the starch to be noncohesive when it is dispersed in an aqueous medium and gelatinized, the heat treated starch being the functional equivalent to a chemically crosslinked or modified starch.

2. The process according to claim 1 in which the native granular starch is selected from the group consisting of native granular corn, pea, potato, sweet potato, barley, wheat, rice, sago, amaranth, tapioca, sorghum, waxy maize, waxy rice, waxy barley, and combinations thereof.

3. The process according to claim 2 in which the starch is selected

from the group consisting of potato, tapioca, waxy maize, waxy rice, waxy barley, and V.O. hybrid waxy maize starch.

4. The process according to claim 1 in which the starch is provided at a pH of 7.5 to 12.

5. The process according to claim 4 in which the starch is provided

at a pH of greater than 8.0 to less than 10.5.

6. The process according to claim 1 in which the native starch is provided at a pH of neutral or greater by slurrying the starch in water and adding a sufficient amount of base to raise the pH of the starch to a level effective to maintain the pH at neutral or basic during the subsequent dehydration and heating steps.

7. The process according to claim 6 in which the base is selected from the group consisting of sodium hydroxide, sodium carbonate,

tetrasodium pyrophosphate, ammonium orthophosphate, disodium orthophosphate, trisodium phosphate, calcium carbonate, calcium

hydroxide, potassium carbonate, and potassium hydroxide.

8. The process according to claim 1 in which the native granular starch is dehydrated to a moisture content of 3% or less before the heating step.

9. The process according to claim 8 in which the native granular

starch is dehydrated to a moisture content of 1% or less before the

heating step.

10. The process according to claim 9 in which the native granular starch is dehydrated to anhydrous before the heating step.

11. The process according to claim 1 in which the starch is heated to a temperature within the range of 100°-200°C.

12. The process according to claim 11 in which the starch is heated to a temperature within the range of 120°-180°C.

13. The process according to claim 12 in which the starch is heated to a temperature within the range of 150°-170°C.

14. The process according to claim 1 in which the heating step is carried out in an apparatus equipped with at least one vent open to the atmosphere.

15. The process according to claim 1 in which the heating step is

carried out in an apparatus equipped with a means for removing water vapor from the apparatus.

16. The process according to claim 15 in which the apparatus is a

fluidized bed reactor.

17. The use of a fluidized bed reactor to prepare a heat treated starch that is noncohesive when dispersed in an aqueous solution and gelatinized using the process according to claim 1.

18. A heat treated starch prepared by the process according to claim 1.

19. A heat treated starch prepared by the process according to claim 1 having a Brabender viscosity of at least 140 B.U. in a 5.4% anhydrous solids dispersion at pH 3 after 20 minutes at 95°C.

20. A heat treated starch prepared by the process according to

claim 1 that achieves no peak viscosity in a 5.4% anhydrous solids dispersion at pH 3 after 20 minutes at 95°C.

21. A heat treated starch prepared by the process according to claim 1 in which the native granular starch initially has been converted.

22. A heat treated starch prepared by the process according to

claim 1 in which the native granular starch initially has been chemically

modified to contain ether or ester substituents.

23. A food comprising at least one heat treated starch prepared by the process according to claim 1.

24. A food comprising 0.1 to 35% of at least one heat treated starch prepared by the process according to claim 1.

25. A starch heated to yield noncohesive texture when dispersed in an aqueous medium and gelatinized.

26. A process for making a heat treated flour that is noncohesive when dispersed in an aqueous medium and gelatinized comprising the steps: a) providing a native granular flour at a neutral or basic pH; b) dehydrating the flour to a moisture content of 5% or less; and c) heating the dehydrated flour at a temperature of 100°C or greater for a period of time effective to cause the flour to be noncohesive when it is dispersed in an aqueous medium and gelatinized, the heat treated flour being the functional equivalent to a chemically crosslinked or modified flour.

27. The process according to claim 25 in which the native granular fiour is selected from the group consisting of native granular corn, pea, potato, sweet potato, barley, wheat, rice, sago, amaranth, tapioca, sorghum, waxy maize, waxy rice, waxy barley, and combinations thereof.

28. The process according to claim 27 in which the flour is selected from the group consisting of potato, tapioca, waxy maize, waxy rice, waxy barley, and V.O. hybrid waxy maize flour.

29. The process according to claim 25 in which the native flour is provided at a pH of 7.5 to 12.

30. The process according to claim 29 in which the native flour is provided at a pH greater than 8.0 to less than 10.5.

31. The process according to claim 25 in which the native flour is provided at a pH of neutral or greater by slurrying the starch in water and adding a sufficient amount of base to raise the pH of the starch to

a level effective to maintain the pH at neutral or basic during the subsequent dehydration and heating steps.

32. The process according to claim in which the base is selected from the group consisting of sodium hydroxide, sodium carbonate, tetrasodium pyrophosphate, ammonium orthophosphate, disodium orthophosphate, trisodium phosphate, calcium carbonate, calcium hydroxide, potassium carbonate, and potassium hydroxide.

33. The process according to claim 25 in which the native granular flour is dehydrated to a moisture content of 3% or less before the heating step.

34. The process according to claim 25 in which the native granular flour is dehydrated to a moisture content of 1% or less before the heating step.

35. The process according to claim 25 in which the native granular flour is dehydrated to anhydrous before the heating step.

36. The process according to claim 25 in which the flour is heated to a temperature within the range of 100°-200°C.

37. The process according to claim 11 in which the flour is heated to a temperature within the range of 120°-180°C.

38. The process according to claim 12 in which the flour is heated to a temperature within the range of 150°-170°C.

39. The process according to claim 25 in which the heating step is carried out in an apparatus equipped with at least one vent open to the atmosphere.

40. The process according to claim 25 in which the heating step is carried out in an apparatus equipped with a means for removing water vapor from the apparatus.

41. The process according to claim 15 in which the apparatus is a fluidized bed reactor.

42. The use of a fluidized bed reactor to prepare a heat treated flour that is noncohesive when dispersed in an aqueous solution and gelatinized using the process according to claim 25.

43. A heat treated flour prepared by the process according to claim

25.

44. A heat treated flour prepared by the process according to claim

25 having a Brabender viscosity of at least 140 B.U. in a 5.4% anhydrous solids dispersion at pH 3 after 20 minutes at 95°C.

45. A heat treated flour prepared by the process according to claim

25 that achieves no peak viscosity in a 5.4% anhydrous solids dispersion at pH 3 after 20 minutes at 95°C.

46. A heat treated flour prepared by the process according to claim 25 in which the native granular fiour initially has been converted.

47. A heat treated flour prepared by the process according to claim 25 in which the native granular flour initially has been chemically

modified to contain ether or ester substituents.

48. A food comprising at least one heat treated flour prepared by the process according to claim 25.

49. A food comprising 0.1 to 35% of at least one heat treated flour prepared by the process according to claim 25.

50. A flour heated to yield noncohesive texture when dispersed in an aqueous medium and gelatinized.