an uncooked dough mix is prepared which includes oat bran as the major amount of the cereal portion . oat bran is the portion of the broken coat of the whole oat which is separated from the other oat components . the oatbran is ground to a particle size of from about 40 mesh to about 60 mesh . as used herein , the term &# 34 ; mesh &# 34 ; means american standard sieve size , unlessotherwise indicated . oat bran is present in the uncooked dough mix at a level of from about 45 percent to about 55 percent , preferably at a level of from about 47 percent to about 51 percent . as used herein , all percentages are by weight , dry basis , unless otherwise specified . it has been determined that an expanded oat bran product cannot be producedby using oat bran alone . extrusion problems and lack of expansion result even when oil is added to a dough mix formed from oat bran . surprisingly , however , it has been found that the addition of a combination of corn branand corn meal to a dough mix containing oat bran provides a product with excellent extrusion and expansion properties , even without the use of an edible oil to facilitate processing through the extruder die . the extrusion and expansion propereties are enhanced by inclusion of triticalein the dough . corn bran is a portion of the broken coat of the whole corn kernel which has been separated from the other kernel components . corn bran , useful in the method of the present invention , has a particle size of from about 60 mesh to about 80 mesh . corn bran is rich in soluble dietary protein , but will not extrude and expand as a result of its own properties . corn meal is produced by dry milling of corn . in general , there are two commercial processes for producing corn meal . in one process , whole corn is ground to a coarse meal between millstones run slowly at a low temperature . this type of corn meal is a whole corn product and , owing to the presence of the germ , has a rich oily flavor and deteriorates rapidly . in the second process , the object of dry milling is to remove the bran and germ and to recover the endosperm in the form of hominy or corn grits , coarse meal , fine meal and corn flour . in an important embodiment of the present invention , it has been determinedthat the extrusion properties and the texture and digestibility of the expanded oat bran product is substantially enhanced by the inclusion of a small , but critical level of a suitable surface active agent , and an edible oil . the surface active agent is preferably present at a level in the range of from about 0 . 1 % to about 0 . 4 % and the edible oil is preferably present at a level of from about 0 . 5 % to about 1 %. the surface active agent is preferably a phospholipid such as lecithin . the addition of the surface active agent and the oil forms in oil in water emulsion in the dough . unlike protein , the surface active agent does not bind water but overcomes the immuscibillity of oil and water to produce an emulsion which , it is believed , provides the improvements with respect to extrusionproperties , texture and digestibility . definitions and standards of identity for dry - milled corn products have been established in the united states by the food and drug administration ( fda ). fda standards are provided for corn meal , and corn flour . the corn meal used in the present invention is degerminated while or yellow corn meal having , on a moisture free basis , a crude fiber content of less than 1 . 2 percent , a fat content of less than 2 . 25 percent , a particle size suchthat not less than 45 percent passes through a no . 25 sieve and not more than 25 percent passes through a no . 72 xxx grits gauze . in general , the corn meal will have a particle size of from about 80 mesh to about 100 mesh . preferably , the corn bran is present in the uncooked dough mix at a level of from about 18 percent to about 25 percent , most preferably the corn bran is present at a level of from about 20 percent to about 23 percent . preferably , the corn meal is present in the uncooked dough mix at a level of from about 10 percent to about 35 percent , most preferably , at a level of from about 16 percent to about 19 percent . triticale , if present , is preferably at a level of from about 5 percent to about 10 percent . the total moisture of the dough is adjusted by the addition of water so as to provide a total moisture level in the dough mix of betweend about 14 percent and about 18 percent , preferably from about 15 percent to about 17percent . the moisture level specified herein includes both free and bound moisture . generally , to attain the desired level of total moisture , water is added to the dough mix at a level of from about 6 percent to about 10 percent . the moisture serves to expand the dough upon extrusion and to aidin gelatinization of the ingredients . the uncooked dough mix is processed in an extruder in accordance with the method and apparatus set forth and described in u . s . pat . no . 4 , 438 , 246 . in the method of this patent heating of the uncooked dough mix is effectedin the extruder die . the temperature of the uncooked dough mix is increasedto within the range of from about 150 ° f . to about 190 ° f . over a period of from about 1 minute to about 1 . 5 minutes to provide a cooked dough mix . during the cooking process the pressure on the dough mixis increased to within the range of from about 600 psi to about 900 psi . asthe cooked dough mix exits from the extruder die , this pressure is releasedand the cooked dough mix expands to provide a cooked cereal product which has expanded in size to from about 3 to about 5 times the volume of the uncooked dough mix , preferably with an expansion of about 3 to about 5 times the volume of the uncooked dough , i . e ., a specific density of from about 0 . 15 to about 0 . 30 grams per c . c . the product exiting from the extruder die should have a total moisture of no higher than 12 percent in order to set the product . preferably , the total moisture of the product exiting from the extruder is from about 8 percent to about 12 percent . the extruded product is then dried to a maximum moisture of 3 percent . higher moistures than 3 percent limit the shelf life of the expanded oat product of the present invention . the temperature used in drying the extruded cooked dough mix product is between about 180 ° f . to about 250 ° f . and drying is effected in a time period of from about 3 minutes to about 6 minutes . the drying is sufficient to remove substantially all free moisture but allows bound moisture to be retained din the product . the process of drying is important to provide adequate shelf life for the expanded dietary product . it should be understood that there is a substantial difference between the method of the present invention for providing an expanded dietary product and the prior art methods for the processing of wheat to provide expanded wheat products . first , it should be noted that the expanded dietary product of the invention is substantially free of cellulose and hemicellulose which are present in wheat . it should also be understood that one of the parameters required to achieve the desired processing of the uncooked dough mix of the present invention is that the oil and moisture levels must be at a lower level than is conventionally used in the production of expanded cereal products , such as wheat based products . such lower level of oil and moisture is required in order to obtain a higher degree of texturization . the fat or oil level should be below about1 percent . uncooked dough mixes prepared from wheat advantageously use 1 - 3 percent oil and about 14 - 18 percent added moisture for extruding from the die of the extruder . furthermore , conventional expanded wheat products have a higher level of mosture upon exiting from the die of the extruder and a lower moisture is needed for the expanded oat bran product of the invention to effect the desired set and maintain the expansion and textureof the dietary product of the invention . the following examples further set forth various features of the invention . a base dough mix was prepared by mixing 150 pounds of oat bran , 62 . 5 poundsof corn bran , 50 pounds of corn meal and 25 pounds of triticale . the mix was moistened with 23 . 5 pounds of water . ______________________________________ oat corn corn bran bran meal triticale______________________________________protein 19 . 09 6 . 0 8 . 0 16 . 0fat 9 . 8 3 . 0 . 6 1 . 5moisture . 8 . 35 11 . 0 11 . 0 13 . 0ash 2 . 82 1 . 0 . 0 . 3 2 . 0carbohydrates 59 . 90 79 . 0 80 . 0 68 0dietary fiber 14 . 99 73 . 0 . 0 . 4 13 . 0insoluble 8 . 6 23 . 36 -- 1 . 3soluble 6 . 39 49 . 64 -- . 11calories 344 50 282 350______________________________________ ______________________________________fructose ( 10 percent moisture ) 7 . 5 poundscinnamon ( 7 percent moisture ) 7 . 0 poundssalt . 5 poundslecithin . 15 poundstotal 15 . 15 pounds______________________________________ the dough mix was thoroughly mixed as disclosed in the method of u . s . pat . no . 4 , 438 , 146 to provide uniform distribution of the ingredients throughout the dough and to provide an uncooked dough mix . the uncooked dough mix was subjected to a pressure of about 900 psi and to a temperature of about 180 ° f . while in the extruder to provide a cooked dough mix . the cooked dough mix exited from the extruder and expanded to 4 times the volume of the uncooked dough mix so as to provide the expanded oat bran dietary product of the invention . the expanded dough mix had a moisture of about 10 percent . a coating of thefollowing formulations was thend applied : ______________________________________corn oil 70 . 00 poundsfructose ( 10 percent moisture ) 30 . 00 poundsvanilla 6 . 00 poundscinnamon ( 7 percent moisture ) 6 . 00 poundslecithin 3 . 00 poundstotal 115 . 00 pounds______________________________________ thus , the flavored coating comprised about 26 percent of the total ingredients before moisture removal . the coated dough mix was then dried to a moisture level of 2 . 5 percent and is ready to eat as a meal replacement . the dough formulation of example i was changed to include the following : ______________________________________percent by weight ( as is ) ingredient______________________________________oat bran 49 . 07corn bran 21 . 30corn meal 17 . 59water 7 . 41cheese flavor 4 . 17salt 0 . 46______________________________________ the base dough was processed in accordance with example i and had an expansion ratio of 4 : 1 . the moisture of the dietary product , after drying , was 2 . 5 percent . the dough formulation of example i was changed to include the following : ______________________________________percent by weight ( as is ) ingredient______________________________________oat bran 47 . 29corn bran 21 . 89corn meal 17 . 51water 8 . 06fructose 2 . 63cocoa 1 . 75vanilla 0 . 88______________________________________ the base dough was processed in accordance with example i and had an expansion ratio of 4 : 1 . the moisture of the dietary product , after drying , was 2 . 5 percent . for this example , the formulation of example i was prepared and processed in accord with example i , except that barley bran was substituted in equalamount for oat bran in the formulation . a new dietary food product has been provided which can serve as a meal replacement , the product not only serving to provide balanced nutrition , but also providing therapeutic effects . the various features of the invention which are believed new are set forth in the following claims .
an improved dietary food product made from ground grain source material in expanded form , comprising more than 10 percent protein and more than 20 percent dietary fiber including from about 55 percent to 70 percent soluble dietary fiber and 30 percent to 45 percent insoluble dietary fiber , the food product having a calorie content of from about 250 to about 350 calories per 100 grams and being expanded from about 1 : 3 to 1 : 5 times .