WO1999051111A1 - Dough compositions for making half-products and farinaceous snacks produced therefrom - Google Patents

Abstract

A farinaceous snack having improved flavor and organoleptical properties is made from an extruded half-product. The half-product is produced from a dough consisting essentially of: (1) a flour blend comprising (a) a starch-based flour component comprising at least about 10 % rice flour; (b) less than about 8 % sugar; (c) at least about 0.5 % salt; (d) leavening comprising sodium bicarbonate; (e) emulsifier comprising monoglyceride; and (2) water. Optionally, starch and/or gluten may be added to the flour component to produce final products having various degrees of crispness. A full-fat, low-fat or fat-free product can be made. Embossing may be used to control expansion, surface greasiness and fat pick-up. The flour is preconditioned and the dough is extruded under low-shear and high-water conditions. The dough composition, which forms sufficient viscosity upon heating and cooling, permits processing the dough at temperatures and work input levels below that which would result in substantial degradation of the starches and/or discoloration and loss of flavor components of the ingredients. A rapid drying method, used to dry the extrudate, improves the manufacturing capabilites without sacrificing the desired product attributes. The extrudates may be dried at a temperature of from about 175 °F (79.4 °C) to about 200 °F (93.3 °C) at a relative humidity (R.H.) of at least about 20 % for about 1.0 hour to about 4 hours. The half-products may be packaged immediately after drying and do not require tempering.

Description

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DOUGH COMPOSITIONS FOR MAKING HALF-PRODUCTS AND FARINACEOUS SNACKS PRODUCED THEREFROM

TECHNICAL FIELD

The present invention relates to dough compositions used to prepare half-products and to farinaceous snacks prepared from the half-products. The present invention further relates to a method for preparing half-products.

BACKGROUND OF THE INVENTION

Many processes and compositions are known in the art for making expanded farinaceous snacks. Although processing of these snacks has been carried out for years, problems are still encountered in reproducing, within a narrow (and predictable) range, product textures, flavors and expansion ratios that ensure the manufacture of products having consistent quality. Problems associated with the expansion properties ofthe half-products, for example, the amount of fat absorbed during expansion when frying the half-products, and the texture and flavor of the finished snacks, have placed added emphasis on developing dough formulas that can be used to produce expanded snacks which are lower in fat and have improved textures and flavors over conventional expanded snacks.

It is known that extrusion process conditions (e.g. barrel temperature, screw configuration, screw speed, moisture content of the dough prior to theπnal processing) can influence the expansion volume of the half-product and change the texture of the finished snack. Typically, the expansion property of the extruded half-product is changed by varying the mechanical input during processing, thereby altering the texture of the finished product. Another method for influencing the expansion has been to apply thermal input in addition to mechanical input during extrusion.

While control of these process parameters provide greater manipulation and control of the finished product texture, the finished products produced from half-products processed in this manner still do not provide finished products having all of the desirable characteristics such as low-fat, crispiness, crunchiness, controlled mouth-melt, controlled mouth clearance, and flavor. The finished products tend to lack crispness and to be either hard, dense, and glassy or airy and foamy. This is due to the cellular structure that is characteristic of these products (e.g., large open cells, non-uniform cells, thin and/or fractured cell walls). The finished products also tend to have a rough surface texture. The uneven expansion and/or the large air cavity resulting from expansion of the half-product after frying is important because the texture ofthe finished product is related to the expanded volume and bulk density. The type of product produced upon expansion of the half-product is largely dependent on the dough composition, the functionality of the ingredients in the dough and the degree of starch gelatinization during processing. Several methods are used to produce conventional expanded snacks. In one method, a dough is formed from a flour/starch/water mixture. The gelatinized to ungelatinized starch ratio is adjusted in the dough so that, upon frying, the half-products expand at least about 1.6 but not greater than 3.0 times the original dimension. The equipment used to produce these types of half-products introduces virtually no shear, therefore the properties of the extruded doughs are essentially unchanged from those of the original dough feed. Other processing methods employing high-temperature short-time extrusion use relatively high screw speeds (300-400 revolutions per minute (φm)) and temperatures of operation of about 285°F (140.6°C).

It has been found that one problem with forming extrudates using conventional methods and formulas relates to the effect of extrusion cooking on materials with relatively high starch contents. Unfortunately, the mechanical and thermal conditions encountered during extrusion result in breakdown in the desired properties of the heat labile flour and starches. These properties (peak and final viscosity) are important for obtaining an extrudate which upon drying produces a half-product cellular structure necessary for obtaining an expanded finished snack that is low-fat, crisp, crunchy, yet light in texture. The extrusion conditions typically used also destroy or volatilize substantial amounts of the desirable flavor (e.g., corn, rice wheat, potato) and/or color components of the flours and starches.

In spite of the efforts made toward achievement of a half-product that results in a finished product having satisfactory organoleptical properties, the known formulas and processes still present serious disadvantages, namely finished snacks which lack uniform cellular expansion and which have undesirable texture.

The present invention substantially alleviates the aforementioned problems by formulating a dough comprising specific starch-based ingredients, and by unique processing conditions including thermal pre-hydration and or followed by extruding the dough under high-water, low shear conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section (magnification 75X ) of a typical extruded marketed product, showing porosity using Scanning Electron Microscopy (SEM).

FIG. 2 is a cross section (magnification 75X ) of a typical extruded marketed product, showing porosity using Scanning Electron Microscopy (SEM).

FIG. 3 is a cross section (magnification 200X) of a typical marketed product showing cell walls using SEM.

FIG. 4 is a cross section of a product made according to the present invention (fried in triglyceride fat) (magnification 75 X ) showing porosity using SEM.

FIG. 5 is a cross section of a product made according to the present invention (fried in triglyceride fat) (magnification 75 X ) showing porosity using SEM.

FIG. 6 is a cross section of a product made according to the present invention (fried in triglyceride fat) (magnification 200X) showing cell wall using SEM. FIG. 7 is a cross section of a product made according to the present invention (fried in non- digestible fat) (magnification 75X) showing porosity using SEM.

FIG. 8 is a cross section of a product made according to the present invention (fried in non- digestible fat) (magnification 75X) showing porosity using SEM.

FIG. 9 cross section of a product made according to the present invention (fried in non-digestible fat) (magnification 200X) showing cell walls using SEM.

SUMMARY OF THE INVENTION

The present invention provides dough compositions used to prepare intermediate compositions (hereinafter "half-products"). The present invention also relates to process conditions for producing the half-products. The present invention further provides full-fat, low-fat or fat-free expanded snacks which exhibit a crispy texture, improved flavor, and a long-lasting crunch without being tooth-packing. The cellular structure, degree of expansion, and texture of the finished product are controlled by formula and/or processing conditions used to produce the half-product.

One embodiment of the present invention is an extrudable dough consisting essentially of: (1) a flour blend comprising (a) a starch-based flour component comprising at least about 10% native rice flour, (b) less than about 8% sugar, (c) at least about 0.5% salt, (d) from about 0.2% to about 1.0% leavening wherein the leavening comprises sodium bicarbonate, and (e) from about 0.1% to about 1.5% emulsifier having at least about 0.3% monoglyceride; and (2) water. Preferably, the rice flour has an amylose content of at least about 10%. The composition preferably comprises, in addition to the rice flour, at least one or more starches selected from the group consisting of native starches, ungelatinzed starches, ungelatinized cook-up starches, and modified starches derived from tubers and grains, for example, potato starch, tapioca starch, corn starch, oat starch, rice starch and wheat starch. The starches are added to the dough composition to produce final products having various degrees of crispness. The flours and starches have a water absorption index (WAI) of less than 3.0. In addition to the flour and starches, gluten may also be added to the dough composition. When gluten is added, the emulsifier additionally includes diacetyl tartaric acid ester monoglyceride.

Another embodiment relates to a half-product prepared by: (1) extruding the dough under high- water, low- shear conditions; and (2) reducing the moisture of the extrudate. The half-product produced from the dough compositions using these processing conditions has a pasting temperature of from about 75.2°F (24°C ) to about 203°F (95°C); a peak viscosity time of at least about 6 minutes; a peak viscosity of from about 10 RVU to about 140 RVU; and a final viscosity of from about 120 RVU to about 350 RVU. The half-product comprises from about 7% to about 14% moisture, and has a WAI of about 3 to about 8, preferably from about 4 to about 6.

Another embodiment relates to an expanded fried product having a pasting temperature of from about 77°F (25°C) to about 203 °F (95°C), a peak viscosity time of from about 3 minutes to about 7 minutes, a peak viscosity of from about 11 RVU to about 55 RVU, and a final viscosity of from about 20 -4-

RVU to about 130 RVU. The snacks have a light, crispy, crunchy texture, improved flavor, and a fat content of from about 11% to about 32%. The moisture content of the fried snack is less than about 3.0%. Minor ingredients which can also be included are sugars, spices, flavorings, and colorings.

DETAILED DESCRIPTION OF THE INVENTION

Important aspects of the invention reside in the following various factors: (1) formulating a dough composition resistant to the shear and processing conditions encountered in the extruder; (2) pre- hydrating of flour by steam and water injection; (3) extruding the dough to produce a half-product having certain visco-elastic properties; (4) drying the extrudate; and (5) frying the half-product to obtain a finished product having certain visco-elastic properties. The unique cellular structure, low-fat levels and finished product texture are important features of the snack products of the present invention. The factors may be used alone, or in any combination to achieve the dough, half-products and/or finished snack products as desired.

The properties of the finished snack are obtained by first preparing a suitable half-product. The half-product is prepared from a dough comprising specific starch-based ingredients (i.e., flours and/or starches) and water. The starch-based ingredients are selected based on their water-holding capacities, and their ability to increase the viscosity of the dough at various temperatures. The specific starch-based ingredients, in conjunction with the steam pre-cooking and higher water levels used during extrusion, permit the use of lower thermal and mechanical energy levels than that generally used in the cooker extruder when preparing half products.

Extrusion damages starches, resulting in finished products exhibiting irregular expansion, decreased crunch, quick moutlimelt without lasting crunch, high fat, greasy appearance, and lack of flavor (due to cellular breakdown and flavor release at the extruder die). In the present invention, however, the specific combination of ingredients compensates for the damage (e.g., loss of ingredient functionality and flavor) that occurs during, and as a result of, the extrusion process.

A. DEFINITIONS

As used herein, "flour blend" refers to a mixture of all dough ingredients, excluding the water. The "flour blend" includes all dry ingredients, as well as any other ingredients such as liquid emulsifier.

As used herein, "extrudate" refers to the wet dough pieces immediately exiting the extruder.

As used herein, "half-product" refers to intermediate moisture snack pieces capable of being expanded in volume individually upon frying. The term half-product includes pellets, collets and expandable pieces of complex shapes, for example, shells, letters, numbers, symbols, animals, flowers, spirals, twists, cones, faces, tubes, fries and stars.

As used herein, "finished product" refers to the half-product that has been fried to produce a ready-to-eat product. -5-

As used herein, the tenns "fat" and "oil" are used interchangeably unless otherwise specified. The terms "fat" and "oil" include edible fatty substances in a general sense, including but not limited to digestible and non-digestible fats, oils, and fat substitutes.

As used herein, the term "water" refers to water which has been added to the dough ingredients. Water which is inherently present in the dough ingredients is not included in the term "water".

As used herein, the tenn "moisture" refers to the total amount of water present, and includes the water inherently present as well as any water that is added to the dough ingredients.

As used herein, "rapid viscosity unit" (RVU) is an arbitrary unit of viscosity measurement roughly corresponding to centipoise.

As used herein, "pasting temperature" is the onset temperature at which the viscosity rises more than 2 RVU units per each °C increase in temperature, as measured using the RVA analytical method herein.

As used herein, "peak viscosity" is the highest viscosity during heating, as measured using the RVA analytical method herein.

As used herein, "peak viscosity time" is the time required to reach the peak viscosity, as measured using the RVA analytical method herein.

As used herein, "final viscosity" is the final peak viscosity after cooling, as measured using the RVA analytical method herein.

All percentages and proportions are "by weight" unless otherwise specified.

B. DOUGH

A particularly important aspect of the present invention is the dough. The dough is formed by combining water with a flour blend comprising: (1) a starch-based flour component comprising native rice flour; (2) sugar; (3) salt; (4) leavening; and (5) emulsifier. The composition of the dough impacts important aspects ofthe finished snack; the two most significant effects are: (1) the ability to process the dough in an extruder to provide a shaped dough piece which remains intact when fried to form thin, crisp, shaped snack products; and (2) the textural and flavor features ofthe finished snack product.

1. STARCH-BASED FLOUR COMPONENT

An important component of the dough is an ungelatinized rice flour. The rice flour is used in combination with other sources of starch-based flour. Suitable sources of other starch-based flour include flours such as tapioca flour, oat flour, wheat flour, rye flour, non-masa corn flour, peanut flour and potato flours (e.g., dehydrated potato flakes and granules, mashed potato materials, and dried potato products). The rice flour can be blended to make snacks of different compositions, textures and flavors. A particularly preferred starch-based flour component is a mixture of non-masa corn flour and rice flour.

Preferably the starch-based flour component comprises flour having the following visco-elastic properties: (a) a pasting temperature of from about 91.4°F (33°C) to about 203°F (95°C), preferably from about 122°F (50°C) to about 194°F (90°C), more preferably from about 123°F (50.6°C) to about 185°F (85°C), and most preferably about 158°F (70°C); (b) a peak viscosity time of from about 3 minutes to about 10 minutes, preferably from about 4.8 minutes to about 7.0 minutes; (c) a peak viscosity of from about 100 RVU to about 360 RVU, preferably from about 146 RVU to about 350 RVU, and more preferably from about 180 RVU to about 205 RVU; and (d) a final viscosity of from about 150 RVU to about 350 RVU, preferably from about 220 RVU to about 345 RVU, and more preferably from about 230 RVU to about 340 RVU. The starch-based flour component additionally has a water absorption index (WAI) of less than 3.0, preferably from about 1.5 to about 2.7, and more preferably from about 1.7 to about 2.5.

The flour blends of the present invention comprise from about 60% to about 99%, preferably from about 70% to about 95% and more preferably from about 75% to about 91% starch-based flour.

At least about 10%, preferably from about 15% to about 50%, more preferably from about 20% to about 40%, and most preferably from about 22% to about 30% of the starch-based flour component is a rice flour, with the balance of the starch-based flour being other flour. In a preferred embodiment, the rice flour has an amylose content of at least about 10%. Particularly preferred flour blends comprise from about 10% to about 25% rice flour, with the balance being defatted non-masa corn flour.

Starch

Starch may also be used in the dough compositions of the present invention. The starch, when added, is used in combination with the starch-based flours noted above. The starch is included in the dough formula if a crispier texture is desired. Examples of suitable starches include native starches, ungelatinzed starches, ungelatinized cook-up starches, and modified starches derived from tubers and grains, for example, potato starch, tapioca starch, corn starch, oat starch, rice starch and wheat starch. Partially gelatinized and gelatinized starches may also be used. When pregelatinzed starches are used, however, they are used in combination with diacetyl tartaric acid ester monoglyceride (DATEM). It has been found that use of pregelatinzed and partially gelatinized starches results in finished products that are gritty. Surprisingly, when DATEM is used in combination with the pregelatinized and partially gelatinized starches the grittiness is reduced substantially.

The starches suitable for use in the present invention have a water absorption index (WAI) of less than 3.0, preferably a WAI from about 1.5 to about 2.7, and more preferably a WAI from about 1.7 to about 2.5.

The flour blends comprise from about 0.5% to about 30.0%, preferably from about 1% to about 20%, more preferably from about 2% to about 10%, and most preferably from about 3% to about 7% starch.

It has been surprisingly found that the use ofthe starch-based flour component, and optionally in combination with starch, results in a dough that can be extruded without substantial breakdown. The flours and starches having the requisite WAI and preferred visco-elastic profile ensures: (1) even water -7-

distribution; (2) proper hydration of the ingredients; (3) an increased viscosity early in the extrusion process; and (4) holding of the viscosity under temperature and shear encountered in the extruder.

Normally, during the extrusion of a dough containing large amounts of various sources of starch- based materials, such as the dough used to form the products of the present invention, the starches compete for water present in the dough. Upon heating, some starches absorb water faster than other starches. The lack of proper hydration of the starches, especially pregelatinized starches, can result in a fried product which may be dense and exhibit grittiness and toothpacking. Some ingredients hydrating more than others, due to the various water absorption indexes of the flours and starches, can result in a fried product having light, puffed, airy structure with fast mouthmelt. The starches also gelatinize and release amylose which is helpful in foπning a cohesive dough sheet and pieces. It is believed that the amylose released during gelatinization is typically not sufficient to withstand the processing conditions (e.g., heat, shear in the extruder) necessary to produce a half product which results in a uniformly expanded fried snack.

The inclusion of flours and starches having various visco-elastic profiles stabilizes the dough and provides a means for producing a product that has improved structure and texture. For instance, because the flours and starches have various peak viscosities and various peak viscosity times, the dough structure remains stable. Further because the water-binding properties of the ingredients vary, during the frying step, the water binding properties of the flours and starches encourage water to be evaporated from the interior ofthe dough. This results in the formation of a multi -layered product having uniformly dispersed voids. The frying oil is thus allowed to enter the porous structure of the extruded dough during the frying step. This ensures that the interior portions of the dough are cooked and fat is evenly distributed. The formation of uniformly dispersed voids and even distribution of the fat is particularly important when fat compositions comprising non-digestible fat are used to fry the final product. This is because large and uneven void spaces provide pockets in which the fat deposits. This results in a fried snack having undesirable texture and greasy and or waxy mouthfeel.

Gluten

Gluten may also be added to the dough composition of the present invention. When gluten is added the dough composition also preferably comprises the emulsifier diacetyl tartaric acid ester monoglyceride (DATEM). The gluten enhances the cohesiveness and viscoelastic properties of the dough. It has been found that when used in combination with DATEM the function of gluten is improved. The gluten added to the dough compositions of the present invention does not include the gluten normally present in the flours. The gluten used in combination with DATEM enhances gas retention and improves the dough's tolerance to mechanical handling. The combination also help the product retain shape.

Gluten, when added, typically comprises from about 0.2% to about 2.0%, preferably from about 0.4% to about 1.2%, more preferably from about 0.5% to about 1.0% of the flour blend. -8-

2. SUGAR

Preferably, sugar is included in the dough compositions of the present invention. Sugar not only affects flavor, but also helps to improve the rheological properties of the dough. Additionally, sugar improves the color and texture of the finished snack. The flour blends of the present invention comprise less than about 8% sugar, preferably from about 2.5% to about 4%, more preferably about 3% sugar.

3. SALT

Preferably, salt is included in the dough compositions of the present invention. Although not well understood, it is believed that the salt has both a functional role in the dough (i.e., alters the physical properties of the dough) and a sensory role in the finished product (i.e., contributes additional and enhances existing flavor). As used herein the teπn salt includes, but is not limited to, sodium chloride, potassium chloride and calcium chloride.

At least about 0.5%, preferably from about 1.0% to about 5%, more preferably from about from about 1.5% to about 3%, salt is included in the flour blends of the present invention. Preferably there is less salt than sugar in the dough compositions.

4. LEAVENING

The dough compositions of the present invention also comprise leavening. From about 0.2% to about 1.0 %, preferably from about 0.3% to about 0.8%, more preferably from about 0.4% to about 0.6% leavening is present in the flour blend. At least about 0.2%, preferably at least about 0.5%, of the leavening is sodium bicarbonate.

It has been surprisingly found that the combination of sodium bicarbonate and DATEM increases the combination of the amount of leavening action beyond the leavening obtained with sodium bicarbonate alone. Other conventional leavening can also be used in combination with sodium bicarbonate. Particularly preferred leavenings include alkali metal carbonates and hydrogen carbonates, e.g. sodium or potassium carbonate, and calcium carbonate. Other leavening agents such as sodium aluminum phosphate can be used, but are not as preferred.

Preferably, the leavening should be of a large particle size or encapsulated to prevent it from evolving gas in the extruder, and thus expanding the product before frying. Preferably a particle size of from about 0.0035 inches (0.088 mm) to about 0.0098 inches (0.250 mm) is used.

The leavening can also be encapsulated in a low-melting fat or shortening so that it is released at the fry temperatures.

5. EMULSIFIER

The dough compositions comprise an emulsifier wherein at least one of the components is a monoglyceride. The monoglyceride may be a substituted monoglyceride, for example acetylated monoglyceride, esters of monglycerides or diglycerides. The emulsifier may additionally comprise an emulsifier selected from the group consisting of DATEM, polyglycerol monoesters, mono and diglycerides of fatty acids, calcium stearoyl-2-lactylate, sodium stearoyl-2-lactylate, and mixtures thereof. The emulsifier helps to control the amount of fat absorbed by the half-product during frying, control the expansion of the half-product during frying, reduce starch breakdown during extrusion and lubricate the extrusion barrels. In the practice of the present invention, it has been found to be particularly advantageous to add the emulsifier to the dry ingredients blend to prevent the starch from hydrating too quickly. The starches are then less susceptible to mechanical shear in the extrusion barrel.

A particularly preferred emulsifier is DATEM. While the precise mechanism of action is not well understood, it is believed that this emulsifier interacts with the leavening during frying, thereby enhancing the effects of the leavening. Particularly preferred is an emulsifier blend comprising DATEM and distilled monoglycerides. This blend is particularly well suited for compositions comprising pregelatinized starch and gluten, if used. Typically the monoglyceride is used as a powder and the DATEM and/or emulsifier is blended with a fat selected from the group consisting of oil, shortening, non-digestible fat, and mixtures thereof.

Diacetyl tartaric acid ester monoglyceride (DATEM) is a fatty acid ester of glycerine which is esterified with diacetyl tartaric acid and a fatty acid having from 12 to about 22 carbon atoms. The fatty acid may be saturated or imsaturated. The Iodine Value (IV) of the diacetyl tartaric acid monoglyceride is from about 50 to about 110. Preferably, the IV is from about 70 to about 85. The diacetyl tartaric acid monoglyceride is a mixture of monoglycerides and diglycerides. The DATEM can be used as a pre-blend with oil, shortening and/or non-digestible fat to increase its flowability.

Polyglycerol esters of lower molecular weight can be used in the dough composition of the present invention. These are predominantly polyglycerols which are diglycerol or triglycerol entities. Any time glycerine is polymerized, a mixture of polyglycerols are formed. Most preferred for use in this invention is a diglycerol monoester which is a mixture of monoesters of polyglycerol, wherein the polyglycerol is predominantly a diglycerol. The preferred fatty acids used to made the esters are saturated and unsaturated fatty acids having from 12 to 22 carbon atoms. The most preferred diglycerol monoester is diglycerol monopalmitate.

Mono- and diglyceride saturated and unsaturated fatty acids having from 12 to 22 carbon atoms can also be used in the dough composition of the present invention. Preferably, the monoglyceride is a distilled monoglyceride such as those derived from, for example, soybean oil, rapeseed oil, cottonseed oil, sunflower seed oil, palm oil, palm olein, safflower oil, corn oil, peanut oil and mixtures thereof. The preferred distilled monoglycerides include, but are not limited to, monoglycerides such as those derived from soybean oil, rapeseed and palm oil and mixtures thereof.

Typically, commercially available monoglycerides contain varying amounts of di- and tri- glycerides. For example, distilled mono-diglycerides comprise about 90% monoglyceride while -10-

undistilled mono-diglycerides comprise about 30% monoglycerides. Either can be used in the dough formulations ofthe present invention.

Sodium stearoyl-2-lactylate or calcium stearoyl-2-lactylate are obtained from the interaction of stearic acid, 2 molecules of lactic acid, and sodium or calcium hydroxide.

The flour blends of the present invention comprise from about 0.1% to about 1.5%, preferably from about 0.3% to about 0.7%, more preferably from about 0.5% to about 0.6% emulsifier. The emulsifier comprises monoglyceride, preferably at a level of at least about 0.3%. Although emulsifier levels as high as 1.5% may be used, this typically results in a finished product that has a hard texture.

6. WATER

Another important characteristic of the dough of the present invention is its water content. The dough is usually prepared by adding water to the flour blend in the pre-conditioner during extrusion. As used herein, the term "water" refers to water which has been added to the dough ingredients. Water which is inherently present in the dough ingredients, such as in the case of the sources of flour and starches, is not included in the term "water". The level of water inherently present in flours and starches is usually in the range of from about 3% to about 18% (they have about 3% to about 18% moisture). As used herein, "moisture" refers to the total amount of moisture present.

The dry dough ingredients are combined with an emulsifier and water to form a dough. The doughs of the present invention comprise from about 18% to about 70% moisture, depending upon the particular stage of processing. The amount of moisture present in the dough changes during the extrusion process. Typically, the doughs of the present invention have a moisture content of from about 18% to about 35%, preferably from about 19% to about 30%, and more preferably from 24% to about 28% in the pre-conditioner. The moisture content of the dough during extrusion and before venting is from about 30% to about 58%, preferably from about 35% to about 52%. The dough has a moisture content of from about 20% to about 40%, preferably from about 25% to about 35%, more preferably from about 26% to about 34% and most preferably about 30% exiting the extruder.

7. OTHER INGREDIENTS

Other ingredients such as flavorings, spices, herbs, coloring, and/or seasonings, vitamins, minerals and oils may be added to the dough compositions of the present invention. Dry ingredients are generally added to the dry dough ingredient mix prior to extrusion. However, the ingredients can also be sprinkled on the surface ofthe snack after frying.

Vitamins, minerals, and other nutrients are typically added to improve the nutritional value of the extruded snacks. The vitamins and/or minerals can be added to the dough and/or added with the seasonings after frying.

8. RHEOLOGICAL PROPERTIES OF THE FLOUR BLENDS -11-

The flour blends of the present invention, which produce doughs delivering the desired texture and structure, have unique rheological properties which render the dough stable during the extrusion process. The flour blends of the present invention have a peak viscosity in the range of about 100 RVU to about 360 RVU, preferably from about 145 RVU to about 215 RVU, and more preferably about 150 RVU to about 210 RVU. The flour blends preferably have a final viscosity of from about 100 RVU to about 450 RVU. The flour blends further have a pasting temperature in the range of from about 91.4°F (33°C) to about 203 (95°C), preferably from about 122°F (50°C) to about 203°F (95°C), more preferably from about 140°F (60°C) to about 176°F (80°C), and a peak viscosity time of from about 3 minutes to about 10 minutes.

The preferred starch-based flour components have a pasting temperature in the range of from about 91.4°F (33°C) to about 203°F (95°C), preferably from about 122°F (50°C) to about 194°F (90°C), and more preferably from about 122°F (50°C) to about 176°F (80°C); a peak viscosity time of from about 3 minutes to about 10 minutes, a peak viscosity of from about 100 RVU to about 360 RVU, and a final viscosity of from about 150 RVU to about 350 RVU.

The rheological properties of the dry ingredients and the flour blends are measured using the RVA analytical method described herein, wherein these ingredients are first hydrated according to the method before testing.

C. PREPARATION OF THE HALF-PRODUCT

1 EXTRUSION

The method used to produce half-products of the present invention is dependent upon use of the starch-based dough composition which, upon gelatinization under conditions of relatively low shear mixing, high water conditions and controlled temperatures, will form a relatively uniform matrix of voids. The half-products are prepared by mixing together the ingredients and then cooking the ingredients using a cooker extruder. The combination of thermal heat (pre-conditioner) and mechanical heat allows an extrudate to be produced using a method that is more gentle than conventional processes. This combination not only allows extrudate to be produced at temperatures less than 220°F (104.4°C), preferably less than 200°F (93.3°C), but it also results in half-products having less starch damage. Half- products processed using the method described herein produce finished products that have substantially improved flavor and texture over finished products produced from conventional half-products. In general terms, the process for producing the half-product comprises mixing and pre-hydrating the ingredients in a pre-conditioner wherein the mixture is partially cooked; conveying the mixture to a portion of the extruder where the mixture is mixed forming a dough-like consistency; fully cooking the mixture under high-water, low-pressure, low-shear conditions; removing the water vapor via pulling a vacuum; cooling the dough and forming the dough into a shape using a die design or post forming equipment; and drying the wet extrudate. -12-

All the ingredients may be mixed together in a batch using a conventional ribbon blender or a continuous mixer before addition to the pre-conditioner, or the ingredients may be added to a pre- conditioner at a metered rate for continuous production, or the ingredients may be pre-mixed and added directly to the extruder.

The extruders suitable for use in this invention include single cooker-extruders as well as twin screw extruders. The twin screw extruders can have screws which are co-rotating or counter-rotating. A preferred extruder is a cooking extruder which uses twin screws and a die which shapes the dough upon exiting the extruder. The preferred type of extruder comprises a dough pre-conditioning element and an extruder equipped with an outlet having a corrugated die orifice which forms indentation on the dough surfaces. The pre-conditioning element and extruder have ports through which steam and/or water is added to the dry starch-containing material to form a dough.

The preferred method used to prepare the products of the present invention include a preconditioning element. The pre-conditioning element can be provided with steam injection from a steam source. The purpose ofthe pre-conditioning element is to ensure that the materials are hydrated, partially cooked, neutralized and that the correct viscosity is produced. Additionally, the use of pre-conditioning in combination with the starch-based flour and specified emulsifier increases the production rate (the rate of extrudate throughput) as compared to conventional extrusion processes.

The pre-conditioner preferably comprises two paddles wherein the paddle sizes are at a ratio of 2:1. In addition to the pre-conditioner, the extruder used in the invention has four main functional sections although each section can be further subdivided. The four main sections are: first, a conveying section; second, a cooking section; third, a venting section; and fourth, a cooling section.

The dough and the extruded half-products of the present invention are prepared by feeding the starch-based ingredients, emulsifier, water and steam into the pre-conditioner. The starch-based materials and emulsifier are fed into the pre-conditioner as separate streams. Tap water and steam are fed through ports in the pre-conditioner. The steam is injected at a temperature of about 212°F (100°C ) to about 350°F (176.7°C). The residence time in the pre-conditioner is in the range of from about 1 to about 4 minutes, and may vary depending on the amount of product present and the mixing rate (measured in revolutions per minute (φm)) in the pre-conditioner. The pre-conditioner is equipped with two counter-rotating paddles (lx and 2x). The pre-conditioner is operated to mix the material, under low shear conditions, into a uniform dough. The mixture in the pre-conditioner is partially cooked. The mixture is processed at a temperature of from about 120°F (48.9°C) to about 200°F (93.3°C), preferably from about 140°F (60°C) to about 185°F (85°C), more preferably from about 160°F (71.1°C) to about 180°F (82.2°C). Preferably, the mixture that exits the pre-conditioner comprises from about 18% to about 35% moisture. The selection of flours and starches provide a dough having the desired visco- elastic properties for feeding into the extruder and for significantly reducing the mechanical and thermal energy required for cooking the dough in the extruder. The use of the starch-based ingredients having -13-

specific visco-elastic properties can have the effect of reducing the amounts of oil/fat in the finished product.

The dough is then conveyed by the screw or screws to the cooking section where heat and additional water are added. Preferably, the extruder is surrounded with heating/cooling means for subjecting the dough to indirect heating/cooling during advancement along the length of the extruder. The water is added to the dough during advancement through the cooking zone to create a high moisture environment. The dough preferably has a moisture of from about 28% to about 70%, preferably from about 30% to about 50%, and a temperature of from about 80°F (26.7°C) to about 220°F (104.4°C). Preferably the temperature in the cooking zone is from about 170°F (76.7°C) to about 200°F (93.3°C), more preferably from about 180°F (82.2°C) to about 190°F (87.8°C). Most of the cooking and gelatinization of the dough takes place in the cooking section of the extruder. The screw or screws in the cooker section are operated such that this section also exerts low shear on the dough ingredients. A speed of about 120 φm to about 180 φm, preferably 130 φm, more preferably about 140 φm, is generally suitable for exerting the desired amount of sheer. The residence time in the cooker extruder (i.e., after exiting the pre-conditioner up to exiting the die) is typically from about 1 to about 2 minutes, preferably from about 1.25 to about 1.5 minutes.

The dough is then conveyed by the screw or screws to the venting section where water is removed under a vacuum of from about 5 inches to about 18 inches of mercury (Hg).

The dough mixture is then passed to a cooling section where the dough is cooled to a temperature of from about 80°F (26.7°C) to about 190°F (87.8°C), preferably from about 100°F (37.8°C) to about 180°F (82.2°C), more preferably from about 110°F (43.3°C) to about 160°F (71.1°C) prior to exiting the extruder. The pressure at the end of the cooling zone is in the range of from about 400 psi (pounds per square inch) to about 1400 psi, preferably from about 500 psi to about 1000 psi.

The extruded shape emerges from the extruder through the die space and die orifice and is cut into snack pieces. The pressure at the die is in the range of from about 200 to about 1000 psi, and the temperature of the dough prior to exit from the die is from about 180°F (82.2°C) to about 220°F (104.4°C), preferably from about 180°F (82.2°C) to about 215°F (101.7°C), more preferably from about 190°F (87.8° C) to about 200°F (93.3°C). The extrudate comprises from about 20% to about 45%, preferably from about 25% to about 35%, and more preferably about 30% moisture.

The die design and configuration affects the expansion ratio of the half-product and the finished product texture. It has been found that products produced from direct die extrusion, with no post extrusion manipulation, must have scoring, corrugation or embossing (hereinafter referred to as "embossing techniques") if extruded in a longitudinal direction. If the die orifice is corrugated then the corrugations are offset. The indentations are preferably made using an extrusion die but can be made after the product is extruded. This provides a finished product with an internal structure and surface that is particularly suitable for reducing the waxy and greasy appearance of the finished product and the -14-

greasy mouthfeel often associated with snacks fried in compositions comprising non-digestible fat. It is believed that extruded products produced from die orifices employing these embossing techniques help to control the expansion and density of the final product, the expansion ratio of the half-product, and the amount of surface grease and/or appearance of surface grease on the finished product. The technique is effective for both two dimensionally (e.g. chips, flat shells) and three dimensionally (e.g. curved shells, cones, pillows) expanded products. The expansion and the amount of fat picked up by three dimensionally expanded products are controlled primarily by the particular shape selected, while surface embossing helps control the amount of fat picked up during frying by two dimensionally expanded products. The three dimensionally expanded products, like twists, have multiple surface channels to allow good fat drainage; this reduces the amount of surface fat, which in turn, substantially reduces the greasy aftertaste often associated with the conventional snacks. Two dimensionally expanded products are relatively thin and have large flat surface areas. The amount of fat picked up by these products during frying is usually high. The overall display upon mastication is mouthcoating. The present invention applies embossing techniques to the surface using a die during extrusion or after extrusion (i.e. post-forming ) to control expansion and fat pickup. The snack pieces can be formed into a variety of shapes by adjusting the shape ofthe extruder orifice.

2 DRYING

After shaping, the extrudate is dried to form the half-product. Conventional drying techniques can be used to form the half-product; however, the quality of the final half-product is substantially improved when the extrudate is dried according to the practice of the present invention. The reason for this is not clear, but it may be that the ingredients present in the composition, which have various water binding capacities and specific rheological properties, help to control the migration of water such that substantially less damage is done to the half-product during the drying process.

Conventional air drying, which is done at a relatively high temperature, is more detrimental to the half-product than a process, such as low temperature drying, that involves a slow constant removal of moisture from the extrudate. Furthermore, conventional drying processes are typically limited by the equipment capabilities. Typically, (1) the extrudate production rate is fixed, and/or (2) the dryer capacities are fixed or have very little ability for change, and (3) the bed depth on the drying equipment is limited (i.e, generally from about 1 inch to about 6 inches). Due to these limitations, drying of the extrudate to a desired target moisture may require high temperature air. This can result in half-products having undesirable attributes. Such undesirable attributes include, but are not limited to, the formation of large and/or not evenly distributed internal voids, appearance of surface cracks, internal fractures, and stress cracking. It is known that these undesirable defects may become evident some time after the half- product is produced.

Of all the quality attributes, texture of the final product is one of the attributes that can be severely altered by the dehydration techniques used when creating or processing the half-product. The -15-

texture is primarily determined by the ability of the half-product to expand, which is controlled by the internal moisture level, moisture distribution, void distribution and void size of the half-product. These properties are highly dependent on how the water is removed during the stages of drying.

The extrudate goes through two distinct stages of drying: (1) the constant rate stage; and (2) the falling rate stage. The amount of time spent in each stage will determine the overall drying rate and influence the properties of the half-product. The external environmental drying parameters (e.g., the drying medium's (air) temperature, relative humidity, flow rate, and bed depth of the extrudate) also influence the diying rate of the product. During the constant rate stage of drying all ofthe environmental parameters are important to achieving maximum drying. However, during the falling rate stage, temperature becomes the primary drying parameter, while the relative humidity, air flow rate, and bed depth (which is related to air flow rate) become secondary parameters for achieving a desired drying rate.

The constant rate drying period is defined as the period of time when the moisture on the surface of the extrudate is available for evaporation at a rate equal to or faster than that which the external environment can remove it from the surface. The falling rate drying period is diffusion limited in that the amount of water evaporated from the surface of the product is limited by the rate at which water is diffused from the interior of the product. The falling rate period is the period of time in which the surface of the extrudate cannot be supplied with the water from the interior at a rate to keep up with the rate of moisture removal from the surface. Moisture diffusion rate within the extrudate controls the rate of moisture supply to the surface ofthe product.

It is desirable to dry the extrudate as quickly as possible while producing a half-product with minimal undesirable attributes. Increasing the drying temperature may be used to increase the removal of moisture from the extrudate. Increasing the drying temperature not only increases the heat transfer and subsequent potential for surface moisture removal, but it also increases the diffusion rate of the moisture from the inside of the extrudate to its surface. Thus, drying medium (air) temperature becomes the controlling parameter for achieving a desired drying rate during the falling rate period of drying that is constrained by extrudate production rate, drying capacity, and bed depth. It has been found that although increasing the air temperature may result in a satisfactory half-product that can be produced within a reasonable time (e.g., <1 hour ), the extrudate typically undergoes non-uniform drying (e.g., moisture gradients are present within the half-product). This results in half-products that develop undesirable stress attributes (e.g., cracks) and which have less than desirable expansion and handling properties.

The undesirable defects caused by drying may be overcome by controlling the migration of water, to ensure that the moisture in the half-product is uniformly distributed. The half-products of the present invention are prepared by: (1) increasing the drying temperature; (2) increasing the relative humidity of the air used to dry the extrudate; and optionally, (3) tempering the half-product at elevated temperatures without further moisture removal. -16-

It has been unexpectedly found that the extrudates of the present invention may be dried using a quick drying process. Preferably, the extrudate is dried to the desired moisture range in less than about 4 hours, more preferably in about 2 hours, and most preferably in about one hour. The extrudates dried according to the present invention result in half-products that expand properly upon frying and which have minimum physical defects that could produce undesirable textural, appearance, or handling attributes. The half-products may be fried or packaged immediately after drying.

In order to dry the extrudates in a conventional hot air dryer to produce the half-products of the present invention, a significant portion of the extrudate's drying time must be spent in the falling rate diying stage. This requires careful management of the drying parameters to avoid incurring any physical defects in the half-product that could produce undesirable textural, appearance, or handling attributes in the finished product. Furthermore, the relationships between the production rate of the extrudate, the drying equipment process capacity, and drying rate must be optimized.

Preferably, the extrudates are dried in air temperatures below about 200°F (93.3°C), most preferably below about 180°F (82.2°C). When air drying temperatures above about 180°F (82.2°C) are used during the falling rate stage, the careful management of the drying parameters to avoid incurring any physical defects in the half-product becomes important. When higher air drying temperatures of about 190°F (87.8°C) to about 200°F (93.3°C) are used for producing the half-products of the present invention, drying at a higher R.H. will reduce the propensity to produce half-product defects. Preferably, a R.H. of from about 20% to about 70%, more preferably a R.N of from about 25% to about 50%, more preferably 30% to 40% is used. The higher R.H. should be increased such that it reduces the severity of drying without greatly affecting the drying capacity. While not wishing to be bound by theory, it is believed that increasing the relative humidity of the drying medium reduces the severity of the drying without substantially affecting the drying rate since the half-product is in the diffusion-controlled falling rate stage of drying. It is also believed that increasing the R.H. also greatly reduces the difference between the wet bulb temperature of the drying air and the half-product's surface temperature, which in turn, reduces the severity of drying. Drying rate may not be greatly affected because moisture removal from the extrudate is controlled by diffusion of water from the interior of the partially dried extrudate to its surface, versus the water holding capacity of the drying medium.

The half-products may optionally be tempered during the drying process or after the drying process is completed to help avoid defects. Tempering, or holding the half-products at a constant temperature without significant moisture removal during a portion or portions of the drying process, can allow moisture diffusion from the interior to increase the moisture available at the surface. Also, some post-drying defects, such as cracking, can be avoided if the half-products are maintained at a temperature of greater than about 120°F (48.9°C) as long as possible after drying. This additional time at a higher than ambient temperature helps reduce the moisture gradient present in the half-product immediately after drying by promoting moisture diffusion within the half-product. Thus, there is less susceptibility to stress cracking later as the remainder of the water within equilibrates. ■17-

A preferred method for reducing the moisture of the extrudate is to dry it at a temperature of from about 175°F (79.4°C) to about 200°F (93.3°C), preferably from about 180°F (82.2°C) to about 190°F (87.8°C), at a relative humidity (R.H.) of from about 20% to about 40%, preferably at a R.H. of about 25%, for about 1.0, preferably from about 1.5 to about 4 hours. Drying times of less than about 1.0 hour can be acceptable if the diying principles are adhered to and no defects are produced. The desired diying process equipment used to dry the extrudates of this invention is a forced hot air convection dryer. Preferably, the extrudate travels through the dryer on a porous conveyor style belt which allows air to pass through the bed of extrudate. The dryer can be divided up into drying zones wherein the diying parameters of (1) temperature, (2) R.H. and (3) residence time can be controlled for each zone. Single zone dryers, dryers of two or more zones and/or dryers with two belts that allow the extrudate to pass and re-pass through the drying zone(s) are also suitable.

The extrudates may also be dried using a 2-step drying process (e.g., pre-drying and drying step). A second dryer, or a pre-dryer can be added in series before the primary dryer. The function of the pre-dryer is to remove as much initial moisture as possible from the extrudate during the constant rate drying stage, before sending it to the primary dryer. A pre-dryer final extrudate moisture is in the range of from about 20% to about 25%. This enables the temperature of the primary dryer to be decreased since less moisture is now present. The decrease in temperature avoids damaging the half-product.

A preferred 2-step method comprises pre-drying the extrudate at a temperature of from about 180°F (82.2°C) to about 200°F (93.3°C) until the extrudate reaches a moisture content of from about 20% to about 25%, and optionally tempering the pre-dried extrudate. After pre-drying/tempering, the partially dried extrudate is further dried at a temperature in the range of from about 180°F (82.2°C) to about 190°F (87.8°C) for a time sufficient to reduce the moisture to less than about 14%. A time of about 1 to about 2 hours is usually sufficient. Thereafter, the half-product (i.e., dry extrudate) may be tempered at a temperature greater than about 100°F (37.8°C), preferably in the range of 100°F (37.8°C) to about 120°F (48.9°C) for a time sufficient to reach equilibrium. The half-product may also be packaged hot out of the dryer, allowing tempering to occur in the package, if frying is to be done at a later time.

Various types of diying equipment can be used to dry the extrudate of the present invention. Hot air impingement ovens provide more effective heat transfer than forced air convection style dryers. Infra-red dryers can be useful, especially during the early constant rate drying stage. Microwave and radio frequency (R.F.) dryers can be particularly well suited to the falling rate drying stage. These dryers promote the diffusion of internal moisture to the extrudate surface. The decision to use any of these drying processes or combination thereof for their particular drying advantage can be determined by one skilled in the art as long as the above principles are followed.

The half-product of the present invention has a moisture content in the range of about 7% to about 14%, preferably from about 8% to about 12%, more preferably from about 9% to about 11%. Half-products with moistures outside of this range exhibit significantly reduced expansion upon frying ■18-

and result in finished products having dense, glassy textures which are less desirable in eating quality. A further moisture restriction of less than about 12% is necessary to ensure micro-stability, if the half- products are not to be fried immediately after drying. Above about 12% moisture, the water activity is increased above about 65%, which is conducive to microbial growth.

The half-product has a pasting temperature of from about 75.2°F (24°C) to about 203 °F (95°C); a peak viscosity time of at least about 6 minutes, preferably about 7 minutes; a peak viscosity of from about 10 RVU to about 140 RVU, preferably from about 11 RVU to about 120 RVU, more preferably from about 13 RVU to about 100 RVU, and most preferably from about 31 RVU to about 65 RVU; and a final viscosity of from about 120 RVU to about 350 RVU, preferably from about 127 RVU to about 265 RVU, more preferably from about 133 RVU to about 250 RVU, and most preferably from about 149 RVU to about 152 RVU.

The WAI of the half-product is typically from about 3 to about 8, preferably from about 4 to about 6, and more preferably from about 5 to about 5.5.

D. PREPARATION OF THE EXPANDED FRIED PRODUCT

1. FRYING

The half-products may be fried using a continuous frying or batch frying process. A fried finished product moisture of less than about 3%, preferably from about 1% to about 3%, and more preferably from about 1.5% to about 2.5%, is desired. While not intended to be bound by theory, the hardness of the finished product increases as a function of decreased moisture content. If the moisture content is too low an excessively hard finished product texture will result.

If desired, the half-products can be fried and then additionally heated with hot air, superheated steam or inert gas to lower the moisture to the desired level. This is a combined frying/baking step.

Preferably the snacks are prepared by a continuous frying method. In this method the pieces are immersed in the oil beneath a moving belt. The continuous fryer design should not allow half-products to float on the surface of the frying oil. This can reduce expansion. Another important continuous fryer parameter is the flow ofthe oil. A low rate of oil flow with respect to the half-product is preferred. High oil flow through the fryer can cause hardening of the outer finished product. While not intended to be bound by theory, this is thought to be due to excessive heat transfer from the oil to the half-product. This increased heat transfer is caused by a reduction of the surface boundary layer by the rapidly moving oil over the surface.

The snack pieces are fried in triglyceride oil at temperatures between about 360°F (182.2°C) to about 390°F (198.9°C), and more preferably about 380°F (193.3°C). The preferred frying residence time is from about 10 to about 30 seconds, more preferably from about 15 to about 20 seconds, or a time sufficient to reduce the moisture content to the requisite level. When fat compositions comprising non- digestible fat are used, the frying oil temperature may need to be increased by at least 5°F to 15°F, -19-

preferably in the range of about 380°F (193.3°C) to about 390°F (198.9°C) ± 15°F (8.3°C) to 20°F (11.1°C) higher than triglyceride fat. The exact fry time is determined by the temperature of the oil and the starting half-product moisture content. The frying time relationship and temperature can be easily determined by one skilled in the art. The finished product fried in fat compositions comprising a non- digestible fat are cooled to about 130°F (54.4°C) to 140°F (60.0°C) within about 10 minutes, and more preferably within about 5 minutes.

The snack products made from this process typically have from about 11% to about 32% fat depending on the shape of the final snack. Preferably, the fried snacks have from about 13% to about 30%, more preferably from about 15% to about 20% fat. A steam stripping step can be included after frying if it is desired to further reduce the fat content.

2. Fats and Oils

The frying can be done in conventional triglyceride oils, or, if desired, the frying can be done in non-digestible materials such as those described in U. S. Patent Nos. 3,600,186 to Mattson et al. (assigned to The Procter & Gamble Co), issued May 12, 1970; 4,005,195 to Jandacek (assigned to The Procter & Gamble Co.), issued January 25, 1977; 4,005,196 to Jandacek et al. (assigned to The Procter & Gamble Co.), issued January 25, 1977; 4,034,083 to Mattson (assigned to The Procter & Gamble Co.), issued July 5, 1977; and 4,241,054 to Volpenhein et al. (assigned to The Procter & Gamble Co.), issued December 23, 1980, all of which are herein incoφorated by reference herein. Frying can also be done in mixtures of conventional triglyceride oils and non-digestible oils.

The terms "fat" and "oil" are used interchangeably herein unless otherwise specified. The terms "fat" or "oil" refer to edible fatty substances in a general sense, including natural or synthetic fats and oils or mixtures thereof, which consist of triglycerides, such as, for example soybean oil, corn oil, cottonseed oil, sunflower oil, palm oil, coconut oil, canola oil, fish oil, lard and tallow, which may have been partially or completely hydrogenated or modified otherwise, as well as non-toxic fatty materials having properties similar to triglycerides, herein referred to as non-digestible fat, which materials may be partially or fully indigestible. Reduced calorie fats and edible non-digestible fats, oils or fat substitutes are also included in the term.

The term "non-digestible fat" refers to those edible fatty materials that are partially or totally indigestible, e.g., polyol fatty acid polyesters, such as OLE AN

The terms "fat" or "oil" also refer to 100% non-toxic fatty materials having properties similar to triglycerides. The terms "fat" or "oil" in general include fat-substitutes, which materials may be partially or fully non-digestible.

By "polyol" is meant a polyhydric alcohol containing at least 4, preferably from 4 to 11 hydroxyl groups. Polyols include sugars (i.e., monosaccharides, disaccharides, and trisaccharides), sugar alcohols, other sugar derivatives (i.e., alkyl glucosides), polyglycerols such as diglycerol and triglycerol, pentearythritol, sugar ethers such as sorbitan and polyvinyl alcohols. Specific examples of suitable -20-

sugars, sugar alcohols and sugar derivatives include xylose, arabinose, ribose, xylitol, erythritol, glucose, methyl glucoside, mannose, galactose, fructose, sorbitol, maltose, lactose, sucrose, raffinose, and maltotriose.

By "polyol fatty acid polyester" is meant a polyol having at least 4 fatty acid ester groups. Polyol fatty acid esters that contain 3 or less fatty acid ester groups are generally digested in, and the products of digestion are absorbed from, the intestinal tract much in the manner of ordinary triglyceride fats or oils, whereas those polyol fatty acid esters containing 4 or more fatty acid ester groups are substantially non- digestible and consequently non-absorbable by the human body. It is not necessary that all of the hydroxyl groups of the polyol be esterified, but it is preferable that disaccharide molecules contain no more than 3 unesterified hydroxyl groups for the puφose of being non-digestible. Typically, substantially all, e.g., at least about 85%, of the hydroxyl groups of the polyol are esterified. In the case of sucrose polyesters, typically from about 7 to 8 of the hydroxyl groups of the polyol are esterified.

The polyol fatty acid esters typically contain fatty acid radicals typically having at least 4 carbon atoms and up to 26 carbon atoms. These fatty acid radicals can be derived from naturally occurring or synthetic fatty acids. The fatty acid radicals can be saturated or unsaturated, including positional or geometric isomers, e.g., cis- or trans- isomers, and can be the same for all ester groups, or can be mixtures of different fatty acids.

Liquid non-digestible oils can also be used in the practice of the present invention. Liquid non- digestible oils having a complete melting point below about 98.6°F (37°C) include liquid polyol fatty acid polyesters (see Jandacek; U.S. Patent 4,005,195; issued January 25, 1977); liquid esters of tricarballylic acids (see Hamm; U.S. Patent 4,508,746; issued April 2, 1985); liquid diesters of dicarboxylic acids such as derivatives of malonic and succinic acid (see Fulcher; U.S. Patent 4,582,927; issued April 15, 1986); liquid triglycerides of alpha-branched chain carboxylic acids (see Whyte; U.S. Patent 3,579,548; issued May 18, 1971); liquid ethers and ether esters containing the neopentyl moiety (see Minich; U.S. Patent 2,962,419; issued Nov. 29, 1960); liquid fatty polyethers of polyglycerol (See Hunter et al; U.S. Patent 3,932,532; issued Jan. 13, 1976); liquid alkyl glycoside fatty acid polyesters (see Meyer et al; U.S. Patent 4,840,815; issued June 20, 1989); liquid polyesters of two ether linked hydroxypolycarboxylic acids (e.g., citric or isocitric acid) (see Huhn et al; U.S. Patent 4,888,195; issued December 19, 1988); various liquid esterfied alkoxylated polyols including liquid esters of epoxide-extended polyols such as liquid esterified propoxylated glycerins (see White et al; U.S. Patent 4,861,613; issued August 29, 1989; Cooper et al; U.S. Patent 5,399,729; issued March 21, 1995; Mazurek; U.S. Patent 5,589,217; issued December 31, 1996; and Mazurek; U.S. Patent 5,597,605; issued January 28, 1997); liquid esterified ethoxylated sugar and sugar alcohol esters (see Ennis et al; U.S. Patent 5,077,073); liquid esterified ethoxylated alkyl glycosides (see Ennis et al; U.S. Patent 5,059,443, issued October 22, 1991); liquid esterified alkoxylated polysaccharides (see Cooper; U.S. Patent 5,273,772; issued December 28, 1993); liquid linked esterified alkoxylated polyols (see Ferenz; U.S. Patent 5,427,815; issued June 27, 1995 and Ferenz et al; U.S. Patent 5,374,446; issued December 20, 1994); liquid esterfied polyoxyalkylene block copolymers (see -21-

Cooper; U.S. Patent 5,308,634; issued May 3, 1994); liquid esterified polyethers containing ring-opened oxolane units (see Cooper; U.S. Patent 5,389,392; issued February 14, 1995); liquid alkoxylated polyglycerol polyesters (see Harris; U.S. Patent 5,399,371; issued March 21, 1995); liquid partially esterified polysaccharides (see White; U.S. Patent 4,959,466; issued September 25, 1990); as well as liquid polydimethyl siloxanes (e.g., Fluid Silicones available from Dow Corning). All of the foregoing patents relating to the liquid nondigestible oil component are incorporated herein by reference. Solid non-digestible fats or other solid materials can be added to the liquid non-digestible oils to prevent passive oil loss. Particularly preferred non-digestible fat compositions include those described in U.S. 5,490,995 issued to Corrigan, 1996; U.S. 5,480,667 issued to Corrigan et al, 1996; U.S. 5,451,416 issued to Johnston et al, 1995; and U.S. 5,422,131 issued to Elsen et al, 1995. U.S. 5,419,925 issued to Seiden et al, 1995 describes mixtures of reduced calorie triglycerides and polyol polyesters that can be used herein. However the latter composition may provide more digestible fat.

The preferred non-digestible fats are fatty materials having properties similar to triglycerides such as sucrose polyesters. OLEAN, a preferred non-digestible fat, is made by The Procter and Gamble Company. These preferred non-digestible fats or oil substitute compositions are described in Young et al., U.S. Patent 5,085,884, issued February 4, 1992, and U. S. Pat. 5,422,131, issued June 6, 1995 to Elsen et al.

Other ingredients known in the art may also be added to the edible fats and oils, including antioxidants such as TBHQ ascorbic acid, chelating agents such as citric acid, and anti-foaming agents such as dimethylpolysiloxane.

3. Texture and Structure of the Finished Snack

The fried products of the present invention have a unique texture and structure. The unique texture and structure is accomplished through the incoφoration of native starch-based flours, modified starch, plus incoφoration of specific emulsifiers into the dough composition and implementation of unique process conditions. The combination of these factors control starch gelatinization and final snack structure.

The texture of the snack of the present invention has four distinct characteristics: longer lasting crispness. crunchiness, and increased lubricity and moutlimelt. "Crispness" as used herein refers to the sensations from the initial bite into the snack. "Crunchiness" as used herein refers to the manner in which the snack particles reduce in size during mastication. Crunchiness can also be thought of as the ability of the snack to maintain crispness during subsequent chewing after die initial bite. "Lubricity" and "mouthmelt" relate to ease or difficulty of reducing the snack in size during mastication. A food that breaks up in the mouth quickly and easily is considered more lubricious and has a faster rate of mouthmelt than a food that requires much time and effort to masticate.

These four characteristics generally interact with each other. For example, typically, extruded snacks are undesirable because they are either hard and tough and do not melt in the mouth quickly or -22-

they are lubricious and do not remain crisp and crunchy during mastication. They are typically very high in fat and greasy, particularly when fried in non-digestible fat. To produce a fried snack from an extruded half-product with a high degree of lubricity, one may have to sacrifice the desirably crunchy attributes for lubricity. Thus, the problem becomes trying to develop a fried snack that is texturally light, lubricious, and breaks up easily in the mouth, yet, at the same time, remains crunchy to chew (i.e., does not become mushy and tooth-packing upon chewing) and does not contain high levels of fat.

Conventional extruded snacks are either texturally lighter or heavier than the products of the present invention. One explanation for this textural difference is the physical and internal structure ofthe products. Conventional extruded products typically have irregularly shaped voids that vary in thickness. This can be seen from Figures 1, 2 and 3. As is evident from Figures 4, 5 and 6 (fried in triglyceride), and Figures 7, 8 and 9 (fried in non-digestible fat), the products of the present invention typically have voids of uniform size and cell walls that are thicker than conventional extruded products.

Another explanation for this textural difference is the embossing produced by the corrugated orifice on both sides of the product. The combination of uniform cell size and thickness, which is related to the rheological properties of the dough and embossing, causes the product of the present invention to be structurally different and texturally more crisp, crunchy and lubricious than conventional extruded products.

The fried snacks of the present invention have a pasting temperature of from about 77°F (25°C) to about 203°F (95°C); a peak viscosity time of from about 3 minutes to about 10 minutes; a peak viscosity of from about 11 RVU to about 55 RVU, preferably from about 12 RVU to about 52 RVU, more preferably about 17 RVU to about 48 RVU; and a final viscosity of from about 20 RVU to about 130 RVU, preferably from about 24 RVU to about 130 RVU, and more preferably about 122 RVU. The finished snacks additionally have a WAI of from about 3.5 to about 4.5, preferably from about 3.6 to about 4.0, and more preferably about 3.8; and an expansion ratio (extruded:expanded) in the range of from about 1:2, preferably in the range of from about 1:1.8. In addition, the finished snacks have no greasy appearance and no greasy mouthcoating.

ANALYTICAL METHODS

1. WATERABSORPTION INDEX (WAD a. Dry Ingredients, Flour Blend and Half-Products

In general, the terms "Water Absoφtion Index" and "WAI" refer to the measurement of the water-holding capacity of a carbohydrate based material as a result of a cooking process. (See e.g. R.A. Anderson et al., Gelatinization of Corn Grits By Roll- and Extrusion-Cooking, 14(1):4 CEREAL SCIENCE TODAY (1969).) -23-

The WAI for a sample is determined by the following procedure:

(1) The weight to two decimal places of an empty centrifuge tube is determined.

(2) Two grams of dry sample are placed into the tube. If a product is being tested, the partical size is first reduced by grinding the product in a coffee grinder until the pieces sift through a US # 40 sieve. The ground sample (2 g) is then added to the tube.

(3) Thirty milliliters of water are added to the tube.

(4) The water and sample are stirred vigorously to insure no dry lumps remain.

(5) The tube is placed in a 86°F (30°C) water bath for 30 minutes, repeating the stirring procedure at 10 and 20 minutes.

(6) The tube is then centrifuged for 15 minutes at 3,000 φm.

(7) The water is then decanted from the tube, leaving a gel behind.

(8) The tube and contents are weighed.

(9) The WAI is calculated by dividing the weight of the resulting gel by the weight of the dry sample:

WAI = ( [weight of tube and gel] - [weight of tube] ) ÷ [weight of dry sample] )

b. Fried Products

The oil is removed from the product using a Carver Lab Press (Model # C). The fried product is placed into a cylinder. The cylinder is put into the press and the hand lever is pressed until the pressure reaches 15,000 lbs per sq. inch after the oil is removed from the product. The product is removed from the cylinder. Steps (1) - (9) above for measuring the WAI of Dry Ingredients, Flour Blend and Half- Products are then followed.

2. RHEOLOGICAL PROPERTIES USING THE RAPID VISCO ANALYZER (RVA)

The rheological properties of the dry ingredients, flour blends, half-products and finished products are measured using the Rapid Visco Analyzer (RVA) model RVA-4. The RVA was originally developed to rapidly measure α-amylase activity in sprouted wheat. This viscometer characterizes the starch quality during heating and cooling while stirring the starch sample. The Rapid Visco Analyzer (RVA) is used to directly measure the cooked viscous properties of the starches, flours, half products and fried products. The tool requires about 2 to 4 g of sample and about 25 grams of water. The weight of sample to use for testing (S) and the weight of water (W) to add to the sample for testing are calculated using the following formulas:

S = 258

100-M

W = 25 + (3 - S) where S = weight of test sample to use (corrected sample mass), in grams (g) -24-

W = corrected water mass (weight of water to add to sample), in grams (g).

M = % actual moisture content of the sample to be tested (before water is added), on a percentage basis (e.g. 12% would be 12, not 0.12). The water and sample mixture is measured while going through a pre-defined profile of mixing, measuring, heating and cooling. This test provides dough viscosity information that translates into flour quality.

The oil present in the sample is removed using a press if the sample is fried. The sample is then ground using a coffee grinder to reduce the particle size. The sample is sieved through a U.S. #40-mesh screen using a stiff bristle paint brush. There is a strong correlation between RVA viscosity profile, product texture (e.g., expansion, grittiness), and work input. Several parameters may be used to characterize the sample. The key parameters used to characterize the present invention are pasting temperature, peak viscosity, peak viscosity time and final viscosity.

RVA METHOD a. Dry Ingredients and Flour Blend

(1) Determine moisture (M) of sample from air oven or Ohaus moisture balance.

(2) Calculate sample weight (S) and water weight (W).

(3) Place sample and water into canister. With paddle turn clockwise and counterclockwise 10 times each. Jog the paddle up and down 10 times.

(4) Place canister into RVA tower and run the following profile:

Profile Time idle and hold @50°C 0 - 1 min ramp to 95°C 1 - 4.45 min hold at 95°C 4.45 - 7.15 min cool to 50^cC 7.15 - 11 min hold at 50°C 11 - 13 min

(5) Following RVA manufacturer's instructions, obtain a print-out ofthe test results for the desired parameters.

b. Half-Products

(1) Grind half products in coffee grinder to pass through #40 sieve

(2) Determine moisture (M) of sample from air oven or Ohaus moisture balance.

(3) Calculate sample weight (S) and water weight (W). -25-

(4) Place sample and water into canister, insert #8 rubber stopper, shake vigorously for 15 sec to 60 sec. (The spindle/paddle can be used to scrape sides of canister)

(5) Insert sample into RVA tower and run the following profile:

Profile Time idle and hold @25°C 0 - 2 min ramp to 95°C 2 - 6 min hold at 95°C 6 - 10 min cool to 25°C 10 - 11 min hold at 25°C 11 - 22 min

(6) Following RVA manufacturer's instructions, obtain a print-out of the test results for the desired parameters.

c. Fried Products

(1) Place product into hydrolic lab press pump (Carver to 15,000 lb/in²)

(2) Take pressed product into coffee grinder for 15 sec

(3) Determined moisture (M) of sample from air oven or Ohaus moisture balance

(4) Calculate sample weight (S) and water weight (W).

(5) Repeat steps (4), (5) and (6) above for half-product RVA method.

EXAMPLES

The following examples illustrate the invention in more detail but are not meant to be limiting thereof.

Example 1

Ingredient % by Wt

Corn Flour 70.0

Rice Flour 12.0

Tapioca Flour 5.0

Modified Starch 8.0

Sugar 2.0

Emulsifier 0.8

Flavor 0.3

Salt 1.4

-26-

Leavening 0.5

TOTAL 100.0

The dough is prepared using a twin screw extruder (Wenger, TX52). The starch-based materials (dry flour mix) and powdered distilled monoglycerides are fed into the pre-conditioner at a rate of approximately 135 lb/hr. Screw speed of the pre-conditioner is at approximately 115 φm. A liquid emulsifier blend of DATEM and cottonseed oil at a ratio of 10:90 is fed into the pre-conditioner at a rate of 20 ml/min. Water is added at a rate of approximately 0.25 lb./min and steam is injected at a rate of approximately 15 lb/hr.

The product entering the cooking extruder has a composition of approximately 70% of the dry blend and 30% water. The extruder is divided into 6 temperature zones. The zones are arranged in series. The first temperature zone is approximately 100°F (37.8°C). The second temperature zone is approximately 160°F (71.1°C). The third and fourth temperature zones, primarily used for cooking, are approximately 200°F (93.3°C). The fifth zone and sixth temperature zones (cooling and venting) are approximately 80°F (26.7°C). Screw speed ofthe extruder is approximately 131 φm.

The product exits through a die shaped like a shell having corrugated surfaces. The extruded product has a moisture of approximately 30%.

2. Example 2

The extruded product of Example 1 is further dried at a temperature of approximately 180°F (82.2°C) under a relative humidity of 20% for about 60 minutes. The half-product is then fried in a nondigestible fat (e.g., Olean®) at a temperature of approximately 380°F ( 193.3°C) for 17 seconds. The fried product has a final moisture of approximately 2% and a final fat content of approximately 26% fat.

Claims

27CLAIMS

1. A dough composition, consisting essentially of:

(1) a flour blend comprising:

(a) from 60% to 99% of a starch-based flour component comprising at least

10%, preferably from 20% to 40%, rice flour; other flour, preferably ground non-masa corn flour, oat flour, tapioca flour, potato flour, peanut flour, wheat flour, rye flour, cake flour or mixtures thereof; preferably from 0.5% to 30% starch; preferably from 0.2% to 2.0% gluten; preferably wherein said rice flour contains at least 10% amylose;

(b) less than 8% sugar;

(c) at least 0.5% salt;

(d) from 0.1% to 1.5% emulsifier having at least 0.3% monoglyceride, preferably wherein the emulsifier is diacetyl tartaric acid ester monoglyceride, polyglycerol ester, stearoyl-2-lactylate or mixtures thereof; and

(e) from 0.2% to 1.0% leavening wherein the leavening comprises sodium bicarbonate; and

(2) water.

2. The dough of Claim 1 wherein the starch-based flour component comprises flour having a pasting temperature of from 91.4┬░F (33┬░C) to 203┬░F (95┬░C); a peak viscosity time of from 3 minutes to 10 minutes; a peak viscosity of from 100 RVU to 360 RVU; and a final viscosity of from 150 RVU to 350 RVU.

3. The dough of Claim 1 or 2 wherein the starch and the starch-based flour component have a water absoφtion index (WAI) of less than 3.

4. A half-product having a pasting temperature of from 75.2┬░F (24┬░C) to 203┬░F (95┬░C); a peak viscosity time of at least 6 minutes; a peak viscosity of from 10 RVU to 140 RVU; a final viscosity of from 120 RVU to 350 RVU; a WAI of from 3 to 8; and from 7% to 14% moisture.

5. A process for producing a half-product having a WAI of from 3 to 8, comprising the steps of: (a) adding a flour blend comprising from 60% to 99% of a starch-based flour component having at least 10% rice flour, the remainder being other flour; less than 8% sugar; at least 0.5% salt; from 0.1% to 1.5% emulsifier having at least 0.3% monoglyceride; from 0.2% to 1.0% leavening wherein the leavening comprises sodium bicarbonate; and optionally starch, to a pre-conditioner; 28

(b) injecting thermal steam or water into the pre-conditioner and processing the mixture under processing temperatures of from 120┬░F (48.9┬░C) to 200┬░F (93.3┬░C) for at least 1 minute to form a partially cooked hydrated mixture comprising from 18% to 35% moisture;

(c) passing the partially cooked hydrated mixture into a cooker extruder while adding moisture to form a dough comprising from 28% to 70% moisture;

(d) cooking the dough at a temperature of from 80┬░F (26.7┬░C) to 220┬░F (104.4┬░C) to form a cooked dough;

(e) passing the cooked dough through a venting zone under a pressure of from 5 to 18 inches Hg to reduce the moisture content of the cooked dough;

(f) cooling the cooked dough;

(g) passing the cooked dough from the venting step to a forming zone and through an extrusion die at a pressure of from 200 psi to 1,000 psi to form an extrudate; and

(h) reducing the moisture of the extrudate to form a half-product, preferably wherein the emulsifier is pre-mixed with fat selected from the group consisting of oil, shortening, non-digestible fat, or mixtures thereof, prior to addition to the pre-conditioner.

6. The process of Claim 5 further comprising the step of frying the dried half-product at a temperature of from 360┬░F (182.2┬░C) to 390┬░F (198.9┬░C) for 15 seconds to 30 seconds in an oil selected from the group consisting of hydrogenated and unhydrogenated cottonseed oil, soybean oil, corn oil, tallow, olive oil, canola oil, rapeseed oil, peanut oil, non-digestible fat and mixtures thereof after the drying step (h) to form a snack piece.

7. The process of Claim 6 wherein the water or steam of step (b) is injected for 2 to 4 minutes and wherein the mixture is processed at a temperature of from 140°F (60°C) to 200°F (93.3°C); the dough of step (d) is cooked at a temperature of from 160°F (71.1°C) to 190°F (87.8°C); the cooker extruder has a screw speed of from 130 φm to 180 φm; and wherein the moisture of the extrudate is reduced by drying the extrudate at a relative humidity of from 20% to 40% and at a temperature of from 175°F (79.4°C) to 200°F (93.3°C) for 1.5 hours to 4 hours.

8. The process of Claim 7 wherein reducing the moisture of the extrudate comprises the steps of: (a) pre-drying the extrudate at a temperature of from 180┬░F (82.2┬░C) to 200┬░F (93.3┬░C) to a moisture content of from 20% to 25%; 29

(b) drying the pre-dried extrudate at a relative humidity of from 20% to 25% for a time sufficient to reduce the moisture content to below 12% to form the half-product; and

( c) tempering the half-product at a temperature in the range of from 100┬░F (37.8┬░C) to 120┬░F (48.9┬░C) for a time sufficient for the half-product to reach equilibrium.

9. Fried snack pieces having a fat content of from 11% to 32%, less than 3% moisture, a WAI of from 3.5 to 4.5, a pasting temperature of from 77┬░F (25┬░C) to 203┬░F (95┬░C), a peak viscosity time of from 3 minutes to 10 minutes, a peak viscosity of from 11 RVU to 55 RVU, and a final viscosity of from 20 RVU to 130 RVU.

10. A flour blend having a pasting temperature of from 122┬░F (50┬░C) to 194┬░F (90┬░C), a peak viscosity time of from 3 minutes to 10 minutes, a peak viscosity of from 100 RVU to 360 RVU, and a final viscosity of from 150 RVU to 350 RVU.