CA1247926A

CA1247926A - Direct expanded, high fat, farinacious product and process thereof

Info

Publication number: CA1247926A
Application number: CA000476225A
Authority: CA
Inventors: Charles V. Fulger; Wen C. Lou
Original assignee: General Foods Corp
Current assignee: General Foods Corp
Priority date: 1984-03-27
Filing date: 1985-03-11
Publication date: 1989-01-03
Also published as: KR850006487A

Abstract

DIRECT EXPANDED, HIGH FAT, FARINACIOUS
PRODUCT AND PROCESS THEREOF

ABSTRACT

A direct expanded farinaceous product having an oil content of at least 6% made by mixing a farinaceous material with an oil content ranging from 6 to 16%
and an effective amount of water; then incorporating a gas into the mixture to provide and aerated cell structure upon extrusion; and extruding the mixture at effective, temperature, pressure and shear effec-tive to partially gelatinize but not dextrinize the starch in the farinaceous material, which product has a foamy texture and maintains its structural integrity in cold and hot fluids.

Description

1~7~2~
case 3309 DESCRIPTION

DIRECT EXPANDED, HIGH FAT, FARINACIOUS
PRODUCT AND PROCESS THEREOF

TECHNICAL FIELD
05 This invention relates to a process for directly expanding a high oil, essentially farinaceous material and a direct expanded, high fat, farinaceous product.
More particular this invention is concerned with extruding a cereal flour-based dough having at leas-t 6% oil into direct expanded breakfast cereals, snack items, pet foods or the like with good texture, flavor and eating characteristics, consumable as is, as well as in hot and cold liguids such as milk.

BACKGRo~ND ART
Extruding cereal products containing high levels of oil have always been a problem. At low levels, however, oils do no-t seem to interfer with the cooker extrusion of flour doughs.
In cereal formulations containing mainly farinaceous materials, the presence of high levels of oil prevent the expansion of the product upon exiting the extruder. Several attempts have been made to extrude cereal products containing high levels of oil. However, as the level of oil approaches about 5~ very little success has been achieved.

~æ'~7926 The following references disclose findings ~here cereals are extruded with various oils.
Mercier et al. in "Formation of Amylose-lipid complexes by Twin Screw Extrusion Cooking of Manoic 05 Starch", Cereal Chemistry Vol. 57, at 4 (1980) disclose that 2 to 4% neutral fat did not affect the e~trusion of manoic starch.
Wiederman et al. in "The Influence of Recipe Variations of Process Parameters and Product Quali-ty Taking Flat Bread as an Example" Lecture, Werner &
Pfleiderer Food Extrusion Presentation, Stutgart, Germany, Dec. 10, 1981 discloses that the introduc-tion of sesame seeds (50% oil) into the extruder feed increases the protein and oil content of the mixture. The protein content raises energy absorp-tion and extrusion pressure, but only to a minor extent because the oil content acts as a lubricating agent. On the other hand, the oil hinders the formation of pores which causes the extrudate density to rise and the degree of expansion to fall off rapidly. ~t 10% sesame seed, the oil contained therein (5%) starts to be pressed out resulting in unstable extrusion conditions.
Certain formula components can increase the extrudability of high fat feedstocks. For instance U.S. Patent No. 3,~23,885 to Hamdy et al. discloses a process for extruding a proteinaceous material containiny up to 5% fat by the addition of small amounts of finely divided ~-cellulose to the extruder.
Hamdy et al. also teaches that substantially more than about 5% by weight of fat cannot be satisfac-torily incorporated by the method of the invention.
This reference claims that such a formula was not satisfactorily extrudable previous to the invention.

. .

~ ~ ~t7~ z ~ -It was further reported by Wiedmann et al. that when feedstock containing whole milk powder is extruded the influence of fat is an overriding factor. Consequently, energy and extrusion pressure 05 all of gently and the degree of expansion at 20%
whole milk powder (5.6% fat in the product based on 28% milk fat levels) falls by approximately half.
The fat content generated pulsating extrusion conditions with many plasticizing zones, even at low concentration, so that normally 3-4% whole milk powder (equaling about 1.2% fat) could not be exceeded.
Split plasticizing zones interspersed with stabilizing conveying makes it possible to add 20% whole milk powder.
Conway in "Extrusion Cooking of Cereals and Soybean -Part I." Food Prod. Dev. 5 27 (1971) reported that for the cooker expansion of a formula with an oil level of about 5%, a starch content o 60% to 70% is needed. When more -than 5% oil is present, either as added oil or oil in the meal fraction the level of expansion will be reduced or prevented.
U.S. Pat. No. 4,325,976 by Harrow et al. discloses extruding rice using a conventional low pressure pasta~type extruder. The extruder composition con-tained a powdered fat. The powdered fat was prepared by spray drying an emulsion of fat and a carrier such as malto-dextrin. The composition had up to 10% spray-dried fat, equivalent to 7~O pure fat. The reason for using powdered fat was to eliminate the effect of extruding fat on the rate of dehyclration. The temperature of the extrusion was not disclosed, however, the resulting product was not expanded. It is known in the art, nevertheless, :~4792~

that pas-ta extrusion is a cold formillg procedure where neither gelatinization nor expansion ta~e place.
Mercier et al. cited supra; U.S. Pat. No.
05 4,369,195 to Nelson et al.; and Mercier et al. in "EfEect of Extrusion Cooking on Potato Starch Using a Twin Screw Ex-truder" disclose -that in the typical low fa-t, high temperature (250 -to 400F) cooker extruder process for cereals, the starch granules are disorganized into a dex-trinous, amorphous structure.
The dextrinization can be demons-trated by X-ray diffraction and by the fact -tha-t extruded s-tarch can become almost completely water soluble. The high water affini-ty and solubili-ty of direc-t expanded, high -temperature, shear and pressure cooked starchy materials can be detrimental in certain applications, where a wa-ter resistant shape and texture stable produc-t is desire.
To date, no one has developed an accep-table, high oil (6% or above~ direct expanded oat or other cereal with acceptable texture and which can be consumed in hot as well as cold fluids such as milk.
As an example, 100% oat cereals which cQntain abou-t 7% oil have been limi-ted to unexpanded gruel-like cooked products. Expanded oat formulae could only be produced with oats as a partial ingredient.

~79~

SUMMARY OF THE INVENTION
The present invention is concerned with a direct expanded, high oil, farinacious product and a process for preparing a direct expanded farinaceous 05 product having high oil content, comprising the steps of: feeding a mixture of a farinaceous material having at least 6~ oil, and water in amounts effective to prepare a dough into an extruder; incorporating a gas into the dough to provide an aerated cell structure upon exiting the extruder; and extruding the dough fox an effective time and at an effective temperature, pressure and shear to partially gelatinize and swell but not dextrinize the starch of the farinaceous material.
DETAILED DESCRIPTION OF THE INVENTION
.. . . . _ _ . _ This invention provides a process whereby farinaceous material with elevated oil content, that is oil content of 6% and above can be satisfactorily expanded, using a low temperature, pressure, and effective shear extruder system. (All %'s herein are understood to be percen-ts by weight). The process is designed to obtain a product where the natural matrix of grain cells is maintained and where the starch granules partial gelatinization and swell without rupturing or substantially dextrinizing.
The necessary cooking temperature results from heating the extruder barrel and by the mechanical heat which results from torque friction. The cooking of typical direct steam expanded cereals results primarily from mechanical energy.
Before proceeding to a more detailed description of the invention, it is necessary to define some relevant terms.

z~

By the term "farinaceous material" lS meant that the formula consists of grain materials such as oat ~roats, oat, wheat, rice, corn, peanu-t, etc., 10ur; grits; full fat, partially or wholly defatted 05 germs; bran fractions optionally milled to a certain particulate size; refined fractions of grain like gluten, starches or oils; as well as lesser optional fractions of desirable non-grain materials such as whole or ground seeds, like sesame seed; beans, like full fat, partially or wholly defatted soy; seeds like rape, sunflower, etc; and/or fractions thereof i.e., protein isolates, oil extracts.
By the term "film forming protein" is meant, that the protein molecules, like grain gluten, readily forms films when native and form moisture barriers when heated.
The term "branll is used in the trade to describe a mix-ture of several botanical tissues: pericarp (fruit coat), seed coat (the pericarp and seed coat are highly adherent at maturity), nucellus, and the outer portion of the endosperm, the aleurone layer.
By the term 'Ibran fiber'l is meant a polymeric carbohydrate moiety of the bran which is not digest-able by humans and which is also known as dietary fiber, and which generally comprises 20 to 90% o~
commercially available bran meal fraction.
By the term "partial gelatinization" is meant that most the starch granules have hydrated and begun to gelatinize and swell, but have not begun to rupture and dextrinize.
By the term "oat bran" is meant the fiberous fraction, sifted from oat flour, which could have various dietary fiber content. However, for conven-ience in this application the oat bran has a 15%
dietary fiber content.

~2479;~6 The term "oil" in the p.resent invention includes vegetable oils as well as animal fat. Vegeta~le oils predominately glycerol fatty acid esters are extracted from a variety of plant seeds nuts, beans 05 and fruits. Sources of vegetable oil are soybeans, cottonseed, peanut, corn germ, olives, coconut, sesame, sunflower seeds, cocoa beans and the like.
Animal fats are generally obtained by processing the fatty tissues of hogs, cattle or fowls.
The term "hot fluid" according to the present invention refers to a fluid such as milk having a temperature ranging from 90F to 180F, preferably between about 103F and 150F; wherein the product produced according to the present invention is contacted with said hot fluid and maintains its most preferred organoleptic tex-tural integrity for at least 5 minutes but p.referably up to about 10 minutes, and its structural integrity in excess of 20 minutes.
By -the term "effective shear conditions" is meant extrusion conditions whereby the extruder is operating at a low screw speed; low extrusion temperature, that is, temperature ranging from 170F
to 240F; and high moisture, that is, moisture ranging from 24% to 34%. Under these conditions -the resulting product exhibits low expansion, high density, low water soluble solid content, and retains its shape in hot and cold fluid, such as milk.
In contrast, under high shPar conditions the product exhibit the following characteristics: high expansion, fluffy light density, high levels of water soluble solid conten-t, and looses its textural integrity in hot water. Whereas, under low shear conditions the results are totally opposite to extrusion under high shear condition. To enhance expansion under effective shear conditions, a gas is ~%~z~

incorporated into the formula-tion as it passes through the extruder.
The first step of the present invention involves feedin~ farinaceous materials having at least 6% oil 05 and water into an extruder wherein said water is in effective amounts to prepare a dough. The farinaceous material can be from a single source, such as 100%
oats, or it can be derived from a variety of sources as set forth above.
It is desired that the farinaceious material or materials used in the present invention have an oil content of at least 6%. Preferably the oil content ranges from 6 to 16%, however, levels of 7 to 14%
are more preferred. The oil can either be added oil or oil present in the farinaceous material. Oil, being hydrophobic in nature has positive attributes when used in cereal products. The oil contributes to maintainin~ the structural integrity of the cereal product when hot fluids such as milk is added.
In the present invention a formulation containing 6 to 16% oil and having a starch content of about 40%
to 75% and preferably 5~% to 65% can be successfully ex-truded into direct expanded products.
In a preferred embodiment of the present inven-tion the farinaceous material is substantially 100%
oat. A 100% oat breakfast cereal is preferred not only for its high oil and protein content, but also because of the wholesome and nutritious image asso-ciated with oat products. This good image is well justified by the pleasant flavor and the naturally high level and ~uality protein and fiber. Also, as a further advantage, the hiyh level of natural antioxidants present stabilizes the polyunsaturated fat content of the oat flour.

~47~6 It is also preferred in the present invention that ~hen bran is employed such as oat bran tha~ it be micromilled to a desirable particle size. This can be accomplished by micromi~ling the flour or by 05 separating the bran and recombining with the flour a~ter micromilling at any proportion desired. In a situation where whole grain such as oats is micromilled, the protein associated with the fibrous fraction becomes exposed. When a whole oat formula is cooked or extruded in the presence of trisodium phosphate the flavor is further enhanced.
~ n option for carrying out the present invention is to incorporate in the farinaceous formula a high level of a film forming protein and/or increased level of bran. A suitable level of film forming protein naturally present or added should range from about 6.5% to 30%, preferably from about 11% to 23%
and more preferably from about 1~% to about 18%.
In the formulation a suitable level of bran, expressed as dietary fiber, should range ~rom 1% to 30% and preferably from 5% to 15%.
When the bran is micromilled to a desirable particle size, the bran micromilling ser~es several purposes; a less gritty product results with better eating characteristics; the micromilled fiber par-ticles diminish the undesirable effects of the high oil content; micromilled bran impart desirable textural characteristics to the finish product by resisting the development of sog~iness whether consumed with hot or cold fluid such as milk; makes the product nu-tritionally more desirable; and imparts more flavor to the product.
Micromilling the bran or whole oats as referred to in the application shall refer to -the production of an average particle under 120 micron in size, a ~;~47~:6 particle size unattainable in most commercially available mills. An Impact Mill manufactured by Vortec Products Company, (Long Beach, CA), will grind material to a selected siæe range. The particle 05 size of -the bran or oats in the present invention should range from 5 to 120 microns. It is preferred, however, that the particle size be about 20 to 80 microns and more preferably about 60 microns.
In the present invention the level of moisture in the formula must be in amounts effective to form a dough and suitably ranges from 24% to 34%, and preferably 28% to 32%. The farinaceous material naturally contains about 8% to 14% moisture.
Accordingly, 10% to 26% moisture should be added, preferably 18% to 22%. The levels of moisture typically added by the State of the Art extrusion to direct expanded cereals is in the 0-12% range. By increasing the moisture level, comparatively gentle processing parameters are achieved, such as decreased temperature, pressure and shear in the extruder.
As some moisture is flashed off upon extrusion the moisture content of the product exiting the extruder ranges from about 16% to about 28%, prefer-ably between about 20% and about 25%.
The farinaceous material, water and other preferred ingredients are mixed and kneaded to prepare a homogenous dough. This mixing and kneading process can be carried out in a first stage or section of the extruder which has temperatures below the cooking range of the ingredients, i~e., below about 130F (55C). Alternately, the mixing can be carried out in a batch process or continuous mixer and then fed into the extruder.

79;26 The farinaceous materials with at least 6% oil and proper amount of water are extruded at low temperature, pressure and effective shear conditions in order to achieve the desired product of the 05 present invention. At low temperature, pressure and shear conditions, sufficient steam is not generated wi~hin the extruder to expand the product as it exits the extruder die orifice. Without expansion the resulting extrudates have a texture similar to cooked pasta. In order to affect expansion while extruding at low temperature, pressure and shear condition, a gas is incorporated. This can be done either by generating from gas forming materials which are added to the formula or by injecting gas directly into the extruder barrel, or by other suitable techniques. Low temperature and pressure processing reduces the surging and slippage within the extruder which is due to the high oil level.
The extrusion conditions (e.g., temperature and shear etc.) are less severe than those employed in typical high temperature cereal extrusion processes where steam puffing provides an aerated product.
Preferred gas forming agents include ammonium carbonate, solid carbon dioxide and sodium bicarbonate as well as carbonates of other metals. The metals carbonates are employed in combination with gas releasing agents such as acid phosphates. ~nother source of gas may include internal gas generators, such as yeast. Another embodiment involves in~ecting a gas such as carbon dio~ide or nitrogen, into the dough during the extrusion. These beneIicially result in an open foamy cell structure which is similar to steam expanded starch-based cereal products.

The dough is subjected to extrusion tempera-tures effective to partially gelatinize and swell but not dextrinize the starch, and to denature the protein. Suitable e~trusion temperatures should 05 range from between about 170F to 240F, preferably between about 190F and 230F. Thes~ -temperatures are suitable for achieving the desired product. The temperature and pressure conditions and the extruder screw element design are adjusted so that minimal effective shear conditions are achieved. At this temperature and gas inclusion conditions, suitable head pressures within the extruder should be between about 200 psig to ~00 psig, and preferably between about 300 psig to 500 psig. Minimal shear condi-tions within the extruder are also achieved byincreasing the moisture level of the dough. Under these conditions, the protein hydrates and denatures into a matri~ while the hydrated, ~elatini7ed and swollen starch granules remain essentially ~o undextrinized, and the oil is maintained in the matrix of the dough without significant expression.
The length of time the mixture remains in the extrudex is dependent upon the temperature, pressure, shear, etc., but generally will be within the range of 15 to 45 seconds and preferahly within the range from 20 to 32 seconds.
The shear conditions are controlled by select-ing proper extruder parameters i.e., pitch, threat number and rpm of the screw, feed rate, moisture level, temperature and pressure conditions.
The work done on the dough is estimated to ~e within a range of 40 to 120 watt hours per pound in a single screw extruder and in the case of a twin screw extruder between 80 and 180 watt hours per pound. These data are calculated by the amperage and ~4~

voltag~ employed with the dough ~eing run in the extruders less the amperage and voltage with the extruders running with water only. A single or twin screw extruder may be employed, with a single screw 05 ex-truder being preferred as it provides a different shear profile exerted on the extruded dough.
The extruder according to the present invention may employ screw pitch, thread design, and depth of flight which are effective to obtain low shear conditions. Short, intense compression sections are applied only to maintain the gas atmosphere.
Upon exiting the extruder the degree of expansion (puff) will be dependent upon the extruder processing parameters, amount of gas forming materials pres~nt and the composition of the formula.
The extrudates exiting the extruder can be cut into desired shapes, and dried/toasted or first partically dried, cut into the desired shape then completely dried/toasted.
The present invention could be applied to several other product areas, beside the already mentioned expanded hot or cold breakfast cereals.
Such products could form the solid, particulate base of a dessert such as Trifle, consumed with a hot or cold custard. It could also be used for sweet and savory flavored snacks like meat or cream filled tubes, "cheese sandwich", sesame stick, potpourri or other products, shelf stable, refrigerated or frozen.
Since an elevated oil formula with optional high protein content and added fiber will resist sogginess when in contack with hot and cold fluids, -the procedure could also be used to make soup or salad croutons. Due to the relatively gentl~ heat process, the extruder feedstocks could be flavored 79;~;

or particulate material could be maintained without de~radation throughout the extrusion process.
EXAMPLE I
A cereal formula consisting of 100% commercial 05 oat flour with an overall oil content of 7%, was fed into an extruder. To produce an expanded aerated product 2% baking powder was also added to the flour as a gas forming material. The feed rate for the open-screw feeder was set at 98 lb/hr. (44 kg./hr.).
The wa~er was fed into the extruder at a rate of 18 lbs/hr. (9 kg/hr.).
In order to extrude the dough mixture, a single screw extruder made by the Wenger Corporation, Sabetha, Kansas, was employed. The approximate operating conditions for the Wenger Model X-20 extruder were as follows: screw RPM 250; head pressure 450 psig (32 kg/cm2); extruder barrel temperatures were maintaind by heating as follows:
~1 55F (13C), ~2 90F (32C), #3 225F (107C), ~4 20 225F (107C), #5 175F (80C). The configuration of the screw consisted o conveyance screws for barrels #1, ~2, #3, and ~4 in that they had a constant depth oE 0.4 inches (10 mm) and a constant pitch of 1.9 inches (48 mm), with the screw within barrel ~5 at the die end having a depth of 0.2 inches (5 mm) and a pitch of 1.9 inches ~48 mm) with the diameter decreasing from 3.3 to 2.5 inches (84 ~m to 64 mm) through a length of 4.5 inches ~114 mm). This screw configura-tion contributes significantly to the effective shear condition necessary for dough extru-sion, with the screw section closest to the die (in barrel #5) being tapered (decreasing in diameter) to effectively extrude through the die orifice. Steam locks were placed between screw section 2 and 3, 3 and 4, and ~etween 4 and 5. The die consisted of a ~Z4~7~26 3/4 inch thick die spacer, with 3, each 3/8 inch circular holes, followed by a backup die 3/4 inch thick, with 8, each l/8 inch circular holes, followed by the die plate with a 4 lobe opening and center 05 pin with a total open area of 0.0123 s~uare inch (0.08 cm ). The work done on the mixture (dough~
was estimated to be about 50 watt-hr/lb and the total residence time of the dough through zones ~2, #3, #4, and #~ was 30 seconds.
The extrusion process consisted of placing the feeder, containing the mixture, over the inlet opening of the extxuder and adjusting the machine to the conditions described above. An excellent cereal type product with a cohesive texture was obtained.
In the cereal product the starch was partially gelatinized but not dextrinized and the matrix was substantially undisrupted. The product was sliced with an Urschel Slicer, air dried and toasted at 375F for 1.5 minutes to obtain the finished cereal.
The dried cereal had a light, crisp airy structure and good texture retention in hot fluids like milk or custards. It was also determined that the textural integrity was maintained beyond 20 minutes standing in said ho-t fluids, like milk or custard.

EXAMPLE II
A cereal formula consisting of 40% micromilled oat bran [40 micron siæe] and 60% regular oat flour was mixed thoroughly and fed into an extruder. The overall ~ormula had a protein content of 18%, bran fiber content of 17.5% and an oil content of 6.8%.
To produce an expanded cereal product 1.8% baking powder, a gas forming material was also added -to the mixture. The feed rate for the open-screw feeder was 35 set at 100 lb/hr. (45 kg./hr.). The water was ~L2L~79~26 fed into the extruder at a rate of 20 lbs/hr. (9 kg/hr.).
In order to extrude the dough mixture, a single screw extruder made by the Wenger Corporation, Sabetha, Kansas, was employed. The approximate 05 operatiny conditions for the Wenger Model X-20 extruder was as follows: screw RPM 275; head pressure 600 psig (42 kg/cm2); extruder barrel temperatures were maintained by heating as follows:
#1 50F (10C~, #2 90F (32C), #3 225F (107C), #4 225F (107C), ~5 175F (80C). The configuration o the screw and the die and their effect was the same as in Example I. The work done on the dough was estimated to be about 70 watt-hr/lb and the total residence time of the mixture (dough) through zones #2, #3, #4, and ~5 was 28 seconds.
The extrusion process consisted of placing the feeder, containing the dough mixtures, over the inlet opening of the extruder and adjusting the machine to the conditions described above. An excellent cereal type product with a cohesive texture was obtained. In the cereal product the starch was partially gelatinized but not dextrinized and the matrix was substantially undisrupted. The product was sliced with an Urschel Slicer, air dried and toasted at 400F for 1 minute to obtain the finished cereal product. The puffed cereal had a fine airy and crunchy texture when consumed dry.
- The product had a cookie-like texture and retained its shape in hot fluid like hot milk.
EXAMPLE III
A cereal formula consisting of 57% commercial oat flour, 37% micromilled oat bran [40 micron size]
and 5% commercial barley malt and 0.9% tri-basic ~479;2~

sodium phosphate dodecahydrate with an overall oil content of 7%, was mixed thoroughly and fed into an extruder. To produce an expanded cereal product 2 baking powder as a gas forming material was also 05 added to the mixture. The feed rate for -the open-screw feeder was set at 115 lb~hr. (5~ kg./hr.~.
The water was fed into the extruder at a rate of 27 lbs/hr. (12 kg/hr.).
In order to extrude the dough mixture, a single screw extruder made by Wenger Corporation, Sabetha, Kansas, was e~ployed. The approximate operating conditions for the Wenger Model X-20 extruder was as follows: screw RPM 275; head pressure 500 psig (35 kg/cm2); extruder barrel temperatures were 15 maintained by heating as follows: #1 50F (10 C), #2 150F ~32C), #3 225F (107C3, ~4 225F (107C), #5 175F (80C). The configuration of the screw and the die and their effect was the same as in Example I.
The work done on the dough was estimated to be about 100 watt-hr/lb and the total residence time of the mixture (dough) through zones #2, #3, #4, and #5 was 28 seconds.
The extrusion process consisted of placing the feeder containing the dough mixtures, over the inlet opening of the extruder and adjusting the machine to the conditions described above. An excellent cereal type product with a cohesive texture was obtained.
In the cereal product the starch was partially gelatinized but not dextrinized and the matrix was substantially undisrupted. This product was sliced with an Urschel Slicer, air dried and -toasted at 375F for 1.5 minutes to obtain the finished cereal product. The cereal attributes were the same as in ., :~ 2L,~79;;~ 6 Example I and II. The product held up equally well in hot and cold fluids like milk.
EXAMPLE IV
A cereal formula consisting of 35% rice flour, 05 40% micr~milled light wheat bran [40 micron size]
and 25% full fat toasted sesame seed was mixed thoroughly and fed into an extruder. The overall formula had a protein content of 12.7%, bran fiber level of 24% and oil content 13.2%. To produce an expanded cereal product 2% baking powder as a gas forming material was also added to the mixture. The feed rate for the open-screw feeder was set at 75 lb/hr. ~34 kg./hr.). The water was fed into the extruder at a rate of 21 lbs/hr. (10 kg/hr.).
In order to extrude the dough mixture, a single screw extruder made by Wenger Corporation, Sabetha, Kansas, was employed. The approximate operating conditions for the Wenger Model X-20 extruder was as follows: screw RPM 225; head pressure 350 psig (25 kg/cm ); extruder barrel temperatures were maintained by hea-ting as follows: #1 50~F (10 C)~
#2 75F (24~C), #3 225F (107C), ~4 225F ~107C~, #5 175F (80C). The configuration of the screw and the die and their effect was the same as in Example I.
The work done on the dough was estimated to be about 115 watt-hr/lb and the total residence time of the mixture (dough) through zones #2, #3, #4, and #5 was 32 seconds.
The extrusion process consisted of placing the feeder con-taining the mixtures, over the inlet opening of the extruder and adjusting the machine to ~he conditions described above. An excellent cereal type product with a cohesive texture was obtained.
The cereal product the starch was partially gelatin-7~2~;

ized but not dextrinized and the ma-trix wa~ substan-tially undisrupted. The product was sliced with an Urschel Slicer, air dried and toasted at 375F for 1.5 minutes to obtain the finished cereal product.
05 The puffed cereal had a desirable texture, with unique properties, such as holding up equally well in hot and cold fluids like milk. The product also had an excellent toasted sesame flavor and taste.

E~AMPLE V
A cereal formula consisting of 35% rice flour, 25% micromilled corn bran [~0 micron size] and 40%
full fat toasted corn germ was mixed thoroughly and fed into an extruder. The overall formula had a 15 protein content of 11.3%, bran fiber 27% and an oil content of 12.4%. To produce an expanded cereal product 1.5% baking powder as a gas forming material was also added to the mixture. The feed rate for ; the open-screw feeder was set at llO lb/hr. (50 kg.
hr-)- The water was fed into the extruder at a rate of 24 lbs/hr. (ll kg/hr.).
In order to extrude the dough mixture, a single screw extruder made by ~enger Corporation, Sabetha, Kansas, was employed. The approximate operating conditions for the Wenger Model X-20 extruder were as follows: screw RPM 250; head pressure 500 psig (35 kg/cm2); extruder barrel temperatures were maintained by heating as follows: #1 50F (10C), #2 150F (66C), #3 230F (110C), #4 230F (110C), #5 30 200F (93C). The configuration of the screw and the die and their effect was the same as in ~xample I.
The work done on the dough was estimated to be about 100 watt-hr/lb and the total residence time of the mixture (dough) through zones ~2, #3, #4, and #5 was 30 seconds.

124~7~2~

The extrusion process consisted of placing the feeder, containing the mixtures, over the inlet opening of the extruder and adjusting the machine to the conditions described above. An excellent cereal 05 type product with a cohesive texture was obtained.
Within the cereal product the starch was partially gelatinized but not dextrinized and the matrix was substantially undisrupted. The product was sliced with an Urschel Slicer, air dried and toasted at 375F for 1.5 minutes to obtain the finished cereal product. The puffed cereal had a desirable texture, with unique properties similar to those in the previous examples.

EXAMPLE VI
A cereal formula as in Example III having an overall oil content o 7%, was mixed thoroughly and fed into the extruder. To produce an expanded cereal product 2% baking powder as a gas forming material was also added to the mix-ture. The feed rate for the open-screw feeder was set at 75 lb/hr.
(34 kg./ hr.). The water was fed into the extruder at a rate of 21 lbs/hr. (10 kg/hr.).
In order to extrude the dough mixture, a single screw extruder made by Wenger Corporation, Sabetha, Kansas, was employed. The approximate operating conditions for the Wenger Model X-20 extruder was as follows: screw RPM 265; head pressure 300 psig (21 kg/cm ); extruder barrel temperatures were maintained by hearing as follows: #1 50F (10C), #2 80F (27C), #3 200F (98C), #4 200F (98C), #5 225F (107C). The configuration of the screw and its effects were the same as in Example I. The die consisted of a 3/4 inch thick die spacer with 3, each 3/8 inch circular holes, followed by a backup ~4~9%6 die 3/4 inch thick, with 8, each 1/8 inch circular holes, followed by the die plate having a ring shape with a total opening area of 0.0123 s~uare inches (0.08 cm ). The work done on the dough was 05 estimated to be about ~0 watt-hr/lb and the total residence time of the mixture (dough) through zones #2, #3, #4, and $~5 was 29 seconds.
The extrusion process consisted of placing the feeder, containing the mixtures, over the inlet opening of the extruder and adjusting the machine to the conditions described above. An excellent cereal type product with a cohesive texture was obtained.
In the cereal product the starch was partially gelatinized but not dextrinized and the matrix was substantially undisrupted. The product was air dried and toasted a-t 375F for 1.5 minutes to obtain the desired cereal product. The puffed farinaceous product had a desirable texture with a tube shape and a hollow center. The hollow center was suitable -20 for filling soft creamy materials e.g., cre~n butter, peanut butter, etc. A bi-textured farinaceous product was obtaine*.

EXAMPLE VII
A fomula as in Example III with an overall oil content of 7% was mixed throughly and fed into an extruder. To produce an expanded aera-ted product 2%
of baking powder, as a gas forming material was also added to the above mixture. The feed rate for the 30 open-screw ~eeder was set as 250 lbs/hr (114 kg/hr).
The water was fed into the extruder at a rate of 63 lbs/hr ~28 kg/hr).
In order to extrude the dough mixture, a co-rotat-ing twin screw extruder made by Werner & Pfleiderer (W/P) Corporation, Ramsey, New Jersey was employed.
The approximate operating conditions for the W/P
Model ZSK-57 were as follows: screw RPM 300; head pressure 500 psig (35 kg/cm2); extruder barrel 05 temperatures were controlled by heating as follows:
~1 150F (66 C), #2 150F ~66C), #3 200F (93C), #4 220F (104C), #5 ~30F (110C). The configuration of the screw consisted of five barrel zones; #l zone had a special deep flight feeding screws; #2 zone had a conveyance screws; ~3 zone had right handed 30 staggered kneading elements; #4 zone had a combination of conveyances and left handed 30 staggered kneading elements; #5 zone had neutral screws that created more even flow and pressure.
The die consisted of one 1 1/2 inch thick spacer, one 1 1/4 inch thick die hole and two star shape dies with total area of 0.0246 s~uare inch (0.16 cm2) opening. The work done on the dough was estimated -to be about 1~0 watt-hr/lb and the total residence time of the mixture (dough) through zones ~2, #3, ~4, and ~5 was 30 seconds.
The extrusion process consisted o~ placing the feeder, containing the mixtures, over the inlet opening of the extruder and adjusting the machine to ~5 the conditions descri~ed above. An excellent cereal -type product with a cohesive texture was obtained.
This product was sliced with Urschel Slicer and was air dried and toasted at 375F for 1.5 minutes to obtain the finished product. The product had similar characteristics to the Example III.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for preparing a direct expanded product comprising:
extruding a farinaceous material having at least 6% oil, water wherein said water is in amounts effective to prepare a dough, and a gas incorporated into the dough to provide an aerated cell structure upon exiting the extruder, wherein the dough is extruded for an effective time and at an effective temperature, pressure and shear to partially gelatinize and swell but not dextrinize the starch of the farinaceous material.

2. A process as defined in claim 1 further comprising the steps of combining said farinaceous material and water in amounts sufficient to form said dough, and incorporating a gas into the dough by means of adding a gas forming material to the dry dough formula or by injecting gas into the dough as it is extruded, to provide an aerated cell structure upon exiting the extruder, feeding the combination into an extruder and extruding the same for a time and at a temperature, pressure and shear effective to partially gelatinize and swell but not dextrinize the starch of the farinaceous material.

3. A process according to claim 1 or 2 wherein the oil content of the farinaceous material ranges from 6%
to 16% by weight.

4. A process according to claim 1 or 2 wherein the oil content of the farinaceous material ranges from 7%
to 14% of the final product.

5. A process according to claim 1 or 2 wherein the gas is incorporated by adding a gas forming agent to the dough.

6. A process according to claim 1 or 2 wherein the gas is incorporated by injecting a gas into the dough while the farinaceous material is extruded.

7. A process according to claim 1 or 2 wherein a gas forming agent is incorporated by injecting a gas into the dough while the farinaceous material is extruded, the gas forming agent being selected from a group consisting of ammonium carbonate and solid carbon dioxide.

8. A process according to claim 1 or 2 wherein the gas is incorporated by injecting a gas into the dough while the farinaceous material is extruded, the gas forming agent comprising sodium bicarbonate or a carbonate or bicarbonate of another metal and a gas releasing agent.

9. A process according to claim 1 or 2 wherein the gas is incorporated by injecting a gas into the dough while the farinaceous material is extruded, and wherein the gas injected into the dough comprises carbon dioxide, nitrogen or combinations thereof.

10. A process according to claim 1 or 2 wherein the gas is incorporated by injecting a gas into the dough while the farinaceous material is extruded, and wherein the gas injected into the dough comprises carbon dioxide.

11. A process according to claim 1 or 2 wherein gas is partially or totally generated in the dough by yeast fermentation.

12. A process according to claim 1 or 2 wherein the water content of the dough ranges from 24% to 34%.

13. A process according to claim 1 or 2 wherein the water content of the dough ranges from 28% to 32%.

14. A process according to claim 1 or 2 wherein the farinaceous material is selected from the group consisting of oat groat, oat flour, oat bran, rice flour, corn bran, corn flour, corn germ, wheat bran, wheat flour, sesame seed, sun flower seed, soy flour, peanut flour and combinations thereof.

15. A process according to claim 1 or 2 wherein the farinaceous material is 100% oat flour.

16. A process according to claim 1 or 2 wherein grain malt is added to the farinaceous material.

17. A process according to claim 1 or 2 wherein the farinaceous material further has film forming protein.

18. A process according to claim 1 or 2 wherein the farinaceous material further has film forming protein and wherein the amount of film forming protein ranges from about 6.5% to about 30%.

19. A process according to claim 1 or 2 wherein the farinaceous material further has bran fiber in a range from about 1% to about 30%.

20. A process according to claim 1 or 2 wherein the dough is fed directly into the extruder.

21. A process according to claim 1 or 2 wherein the dough is subjected to extrusion temperatures ranging from 170°F to 240°F.

22. A process according to claim 1 or 2 wherein the dough is subjected to extrusion temperatures ranging from 190°F to about 230°F.

23. A process according to claim 1 or 2 wherein the dough is subjected to extrusion temperatures for 15 to 45 seconds.

24. A process according to claim 1 or 2 wherein the dough is subjected to extrusion temperatures from 20 to 32 seconds.

25. A process according to claim 1 or 2 wherein the dough is subjected to pressures within the extruder ranging from 200 to 700 psig.

26. A process according to claim 1 or 2 wherein the dough is subjected to extrusion temperatures from 20 to 32 seconds and wherein the dough is subjected to pressure within the extruder ranging from 300 to 500 psig.

27. A process according to Claim 1 or 2 wherein the work carried out on the dough is within the range of about 40 to 180 watt-hr./lb.

28. A process according to Claim 1 or 2 wherein the extrusion is carried out in a single screw extruder.

29. A process according to claim 1 or 2 wherein the farinaceous material is extruded on a twin screw extruder.

30. A process according to claim 1 or 2 wherein the starch content of the farinaceous material ranges from 40% to 75%.

31. A process according to claim 1 or 2 wherein the starch content of the farinaceous material ranges from 55% to 65%.

34. A direct expanded product comprising a farinaceous material having at least 6% oil and starch, said starch being partially gelatinized and swollen but not dextrinized, which product has an open foamy cell structure and said product maintains its structural integrity in cold and hot fluids.

35. The product of claim 34 wherein the oil content of the farinaceous material ranges from 6% to 16% by weight.

36. The product of claim 34 wherein the oil content of the farinaceous material ranges from 7% to 14% by weight of the product.

37. The product of claim 34, 35 or 36 wherein the farinaceous material is selected from the group consisting of oat groat, oat flour, oat bran, rice flour, corn bran, corn flour, corn germ, wheat bran, wheat flour, sesame seed, sun flower seed, soy flour, peanut flour and combinations thereof.

38. The product of claim 34, 35 or 36 wherein the farinaceous material is 100% oat flour.

39. The product of claim 34, 35 or 36 wherein grain malt is included with the farinaceous material.

40. The product of claim 34, 35 or 36 wherein the farinaceous material further has film forming protein.

41. The product of claim 34, 35 or 36 wherein the farinaceous material further has film forming protein and wherein the amount of film forming protein ranges from about 6.5% to about 30%

42. The product of claim 34, 35 or 36 wherein the farinaceous material further has bran fiber in a range from about 1% to about 30%.

43. The product of claim 34 wherein the product is a direct expanded breakfast cereal.

44. The product of claim 34, 35 or 36 wherein the starch content of the farinaceous material ranges from 40% to 75%.

45. The product of claim 34, 35 or 36 wherein the starch content of the farinaceous material ranges from 55% to 65%.

46. The product of claim 34 or 43 wherein the product is a cereal product having bran with a particle size of about 5 to 120 microns.