A reduced-flatulence, legume-based snack food including legumes, additional grain-based ingredients, an aqueous solvent, and processing aids. The legumes have greater than 45 percent by weight of the oligosaccharides and saccharides removed therefrom. The legumes, additional grain-based ingredients, aqueous solvent, and processing aids are processed together to provide the snack food with a developed matrix so that the snack food exhibits a high crunch texture and a low fat absorption when cooked.

BACKGROUND OF THE INVENTION
 The present invention relates generally to a food products made from
 legumes. More particularly, the present invention relates to high-fiber,
 high-protein, reduced-flatulence snack foods.
 Many types of legumes possess a variety of nutritional components, such as
 protein and fiber, in advantageous concentrations so that it is desirable
 to incorporate legumes into food products. In spite of these potentially
 beneficial sources of nutrients, the use of legumes in food products has
 been limited because many legumes produce flatulence after their
 digestion. Flatus produced in a person's intestinal tract not only leads
 to the potential for social embarrassment, but also causes personal
 discomfort, including abdominal rumblings, cramps, pain, and diarrhea.
 As food is digested in humans, flatus is typically generated in the stomach
 and intestines. For most people, flatus generation rates are typically
 between 16 and 64 milliliters per hour. Factors that are known to impact
 flatus generation rates include diet, age, physiological status, and
 medical status. One particular type of food that is known to enhance
 flatus generation rates is legumes. Flatus production rates for certain
 legumes are as follows:

Food ingredient Intake Flatus
 Full fat Soya 146 g 30 ml/h
 Soybeans 100 g 36 ml/h
 Defatted Soya 146 g 71 ml/h
 Navy bean 146 g 179 ml/h
 meal
 Whole Bengal 40 g 52 ml/h
 gram
 Bengal gram 40 g 44 ml/h
 (cotyledon)
 California 100 g 120-137
 white beans ml/h
 California 450 g 36 ml/h
 white beans
 Lima beans 100 g 42 ml/h
 Mung beans 100 g 25 ml/h
 Dutch brown 250 g 72 ml/h
 bean
 Dun peas 210 g 21 ml/h
 Lentils 200 g 41 ml/h
 Red kidney 100 g 84 ml/h
 beans
 Attempts have been made to process legumes to reduce the amount of flatus
 generated during digestion. A primary drawback of these processes is that
 in addition to removing sugars that cause flatus, the processes also
 remove other desirable ingredients, such as vitamins, minerals, and
 soluble carbohydrates, from the legumes. Because these desirable
 ingredients are removed from legumes, the nutritional value of legumes is
 reduced.
 Rockland et al., U.S. Pat. No. 3,318,708 (hereinafter "Rockland et al.
 '708"), and Rockland et al., U.S. Pat. No. 3,352,687 (hereinafter
 "Rockland et al. '687") disclose processes for producing quick-cooking
 legumes. The processes each describe placing dry beans in a hydrating
 medium and then subjecting the beans to cycles of vacuum and atmospheric
 pressure until the beans are hydrated to a desired extent. The hydrating
 medium used in these processes contains sodium chloride, a chelating agent
 and an alkaline agent. Rockland et al. '708 discloses drying the hydrated
 beans to a moisture content of between 9.5 and 10.5 percent. Rockland et
 al. '687 discloses freezing the hydrated beans until the beans are used.
 Rockland, U.S. Pat. No. 3,635,728 (hereinafter Rockland '728") describes a
 process for making quick-cooking soybean products in which bitterness and
 other undesired taste qualities of the soybeans are reduced. The process
 includes briefly contacting the beans with boiling water and then soaking
 the beans in an aqueous solution containing sodium chloride, a chelating
 agent, and an alkaline agent. The treated soybeans are then either dried
 or frozen.
 Rockland et al., U.S. Pat. No. 4,124,727 (hereinafter "Rockland et al.
 '727"), discloses further processing of the hydrated legumes disclosed in
 Rockland et al. '708, Rockland et al. '687 or Rockland '728 to prepare a
 nutritionally balanced protein snack foods from legumes. This process
 includes mashing the hydrated legumes. A dough is then formed by mixing
 the mashed legumes with water methionine-containing ingredients, such as
 cereal grain flours, oil seeds, or oil seed flours. The dough is shaped
 and then fried in an edible oil.
 Matsumoto et al., U.S. Pat. No. 4,748,037, describes using a twin screw
 extruder to produce snack-like cakes from various types of beans. The
 process includes feeding whole or hulled beans into a twin-screw extruder.
 During the extrusion process, the moisture content of the beans is between
 8 and 50 percent. Extrusion causes the starch component of the beans to
 swell while texturizing the protein component of the bean so that the
 beans are formed into a cake.
 Wagner et al., U.S. Pat. No. 3,876,807, describes a process for increasing
 the digestibility of legumes by maintaining the legumes in a medium having
 a pH of between 5.0 and 5.5 and a temperature of between 45.degree. C. and
 55.degree. C. for between 24 and 48 hours. Lawhon et al., U.S. Pat. No.
 4,645,677, discloses a process for removing flatulence-causing sugars from
 bean products by forming a solution of water and ground beans and then
 ultrafiltering the solution through a molecular weight cutoff of between
 30,000 and 100,000 daltons. Stahel, U.S. Pat. Nos. 4,450,176 and
 4,543,264, disclose methods for making beans more digestible by extracting
 components from the beans by exposing the beans to alcohol vapors.
 SUMMARY OF THE INVENTION
 The present invention is a reduced-flatulence, legume-based snack food made
 from legumes, additional grain-based ingredients, an aqueous solvent, and
 processing aids. The legumes have greater than 45 percent by weight of the
 oligosaccharides and saccharides removed therefrom. The legumes,
 additional grain-based ingredients, aqueous solvent, and processing aids
 are processed together to provide the snack food with a developed matrix
 so that the snack food exhibits a high crunch texture and a low fat
 absorption when cooked.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 The present invention includes legume-based snack foods that are high in
 fiber and protein while exhibiting a decreased rate of flatus generation
 when digested. The present invention also includes a process for producing
 legume-based snack foods that are high in fiber and protein but exhibit a
 decreased rate of flatus generation when digested. A summary of the
 process of the present invention is outlined in FIG. 1.
 As used herein, reference to the legume-based snack foods being high in
 fiber means that the legume-based snack foods have a protein concentration
 of between about 13 and 32 percent by weight on a dry matter basis.
 Reference to the legume-based snack being high in protein means that the
 legume-based snack foods have a fiber concentration of between about 4 and
 16 percent by weight on a dry matter basis. Unless indicated to the
 contrary, all references to percent concentration in the present
 application are percent by weight.
 Most legumes are good sources of protein, possessing between about 17 and
 25 percent protein on a dry matter basis. Legumes are also typically a
 good source of fiber and carbohydrates as well as many vitamins,
 potassium, magnesium, and antioxidants. Because of these characteristics,
 it is desirable to produce legume-based snack foods. Legumes used in
 producing the legume-based snack foods according to the present invention
 have the added characteristic of containing reduced the concentrations of
 soluble sugars, such as oligosaccharides and polysaccharides, which are
 known to cause flatus when digested.
 Because the legumes used in producing the snack foods produced according to
 the present invention have reduced concentrations of flatulence causing
 components, persons will be able to consume the snack foods without being
 concerned about having to suffer through the discomfort and social
 embarrassment associated with flatulence that typically results when
 consuming other legume-based foods. As such, persons will be more likely
 to consume snack foods produced according to the present invention so that
 the persons can benefit from having a diet that contains the nutritional
 components found in legumes.
 While legumes proteins are rich in lysine, legumes are frequently not a
 good source of sulfur-containing amino acids, such as methionine and
 cystine. To compensate for these deficiencies and thereby provide protein
 having a nutritional quality that is similar to meat, the present
 invention uses cereal grain flours, oil seeds, and oil seed flours. Using
 these additional ingredients in conjunction with legumes enables the
 mixture thereby produced to have a complete amino acid profile.
 The process of the present invention is suitable for use with a wide
 variety of legumes, beans, and other plants that contain and release
 certain sugars upon ingestion, resulting in flatulation in humans or
 animals. Examples of suitable legumes include field bean (Phaseolus sp.),
 white pea bean (also known as navy bean), Tepary bean (P. acutifolius var.
 latifolius), Mung bean (P. aureus) (also known as Chickasaw pea, Oregon
 pea, Neuman pea, Jerusalem pea, or chop suey bean), lima bean (P. limensis
 or lunatus var. macrocarpus), Broadbean (Vicia faba), Chickpea (Cicer
 arietinium), lentil beans (lentilla lens), peanuts (Arachis hypogaea),
 buckwheat (Polygonaceae), and flax (Linum usitatissum).
 In an initial mixing step 10, legumes 12 are mixed with water 14 and
 processing aids 16. The legume mixture is then allowed to hydrate 20 until
 the legumes achieve a hydration point of between about 125 and 385 percent
 by weight of the dried weight of the legumes. Unless indicated otherwise
 in this application, all references to percent are percent by weight.
 To enhance the hydration rate, the water is heated to a temperature of
 between about 50.degree. F. and 210.degree. F. Preferably, the water is
 heated to between about 175.degree. F. and 180.degree. F. To enhance the
 rate at which the legumes are heated, a portion of the water 14 added in
 the mixing stage 10 may be replaced with steam 18. Maintaining the water
 at a temperature in this preferred range enables the legumes to attain a
 desired degree of hydration in approximately 15 to 30 minutes.
 To further reduce the time for the legumes to attain a desired degree of
 hydration, it is desirable for the legumes to be ground a grit size of
 between about 2 and 4 millimeters. Preferably, the legumes are ground to a
 grit size of between about 3 and 4 millimeters.
 Because the legumes are ground when used in conjunction with the present
 invention, it is possible, and even preferable, to use broken legumes as
 the starting material. Using broken legumes in the present invention is
 highly desirable because broken legumes are a less costly material than
 unbroken legumes.
 The hydration rate is also preferably enhanced by the addition of
 processing aids that assist in the disruption of the cellulose portion of
 the legume. As the processing aids enter the legume, the cotyledon of the
 legume is also disrupted so that the cellulose component of the cotyledon
 becomes porous and thereby enable water to totally infiltrate into the
 legume substructure.
 The processing aids are also selected based on the ability to whiten the
 legumes and the ability to produce a given taste consistency in the final
 product, such as a tortilla-like taste that is common in a niximization
 process. Niximization is described as a reaction which takes place between
 the carbohydrates of corn-based grits and lime in the presence of excess
 water and some thermal heat. It is the process by which masa is produced
 for making of tortilla chips. It also can be described as a process that
 allows for the gelatinization of approximately 25 percent of the starch
 granules within the corn flour.
 Processing aids that are suitable for use with the present invention
 include CaO, CaCO.sub.3, CaOH, CaSO.sub.2, KOH, KCO.sub.2, Na.sub.2
 SO.sub.4, Na.sub.2 CO.sub.3, NaO, NaCl, NaOH, C.sub.2 H.sub.4 O.sub.2,
 C.sub.2 H.sub.3 NaO.sub.2, or combinations thereof. The processing aids
 are preferably added to the legume and water mixture at a concentration of
 between about 0.1 and 1.5 percent. Preferably, the processing aids
 includes a mixture of CaO, CaCO.sub.3, CaOH, where each processing aid has
 a concentration of between about 0.01 percent and 5.0 percent of the raw
 legume material. The total concentration of processing aids in this
 preferred configuration is less than about 10 percent by weight of the raw
 legume material.
 When selecting processing aids, it is important that the processing aids do
 not produce an off-flavor in the final product. Two preferred processing
 aids for use with the present invention are CaO and CaCO.sub.3. Using
 these processing aids at concentrations of between about 0.5 and 1.0
 percent produced snack foods having a taste that was similar to corn-based
 tortilla chips. The use of these processing aids also produces texture and
 crunch characteristics that were similar to tortilla chips.
 The processing aids and the heat used during hydration play an important
 role in enhancing the total sugars removed from the legumes. At
 temperatures above 165.degree. F. and durations of between 20 and 30
 minutes, the hydration rates and cotyledon disassociation rates are
 maximized. The processing aids also preferably maintain the pH of the
 legume and water mixture between about 8.0 and 8.7. These factors are also
 directly related to producing snack foods with desirable taste
 characteristics.
 Using legumes with a grit size of between about 3 and 4 millimeters
 enhances the ability to handle the legumes emerging from the hydrator
 because the hydrated legumes are more similar to solid particulates than a
 mush or single mass.
 After the legumes have attained a desired degree of hydration, the legumes
 are extracted 30 using a high pressure expeller to thereby produce a
 legume press cake. Passing the hydrated legumes through the expeller
 produces an extracted solution 32 that contains water as well as most
 soluble sugars from the bean matrix. The expelled water typically contains
 all soluble sugars, oligosaccharides, polysaccharides, and starches as
 well as some soluble vitamins. Extraction does not fully disrupt the cell
 structure of the endosperm.
 The expelled water is typically classified as either free water and
 interstitial water. The free water is loosely contained as a medium
 wherein the particles are suspended. The interstitial water is trapped
 between the crevices and interstitial spaces of the suspended solids.
 It has been found that the amount of soluble sugars removed from the
 legumes is directly proportional to the pressure exerted in the expeller
 and the percentage of water removed from the legume mixture. The
 concentration of expelled water is typically between about 45 percent and
 65 percent of the total hydrated water in the legume mixture. The removal
 of soluble sugars from the legumes is further enhanced by osmotic
 pressures of the cotyledon, which is caused by leaching of the soluble
 sugars occurring in the water present within the intercellular water of
 the cotyledon. Water in this area is classified as free water and this
 type of water is the easiest to remove from the legume mixture. Therefore,
 the amount of soluble sugars removed from the legume mixture is greater
 than 45 percent. Preferably, the process of the present invention removes
 more than 65 percent of the soluble sugars from the legume mixture.
 To further enhance the amount of water that is removed from the legume
 mixture, the legume mixture is preferably subjected to evaporation 40. In
 the evaporation stage, between about 1 and 18 percent of the water 42
 remaining in the legume press cake is removed from the legume press cake.
 At this point, the legume press cake has a moisture content of between
 about 35 and 75 percent.
 After evaporation, additional ingredients 52 are added to the legume press
 cake to produce a dough mixture that possesses a complete amino acid
 profile. The mixture thereby enables snack foods produced according to the
 present invention to have a total dietary protein content having a
 nutritional content that is similar to meat protein.
 Additional ingredients that are suitable for use with the present invention
 include cereal grains, oil seeds, and oil seed flour. Examples of suitable
 cereal grains are wheat flour, corn flour, buckwheat, spent barley, and
 combinations thereof. The legumes and additional ingredients are
 preferably mixed together at a weight-to-weight ratio of about 7:3. A
 person of ordinary skill in the art will appreciate that it is also
 possible to add other flavoring agents and colors to the dough mixture
 during this stage.
 When it is desired for the legume-based snack foods to have a protein
 concentration proximate to a lower end of the protein concentration range,
 high-starch based cereals are selected for the additional ingredients.
 When it is desired for the legume-based snack foods to have a protein
 concentration proximate to an upper end of the protein concentration
 range, gluten, soya isolate or casein are selected for the additional
 ingredients.
 When it is desired for the legume-based snack foods to have a fiber
 concentration proximate to a lower end of the fiber concentration range,
 whole grains including bran and some hulls are selected for the additional
 ingredients. When it is desired for the legume-based snack foods to have a
 fiber concentration proximate to an upper end of the fiber concentration
 range, defatted bran, high fiber containing grains, or pure fibers are
 selected for the additional ingredients.
 The dough mixture is then cooked 50. Cooking in an extruder is preferably
 accomplished by three mechanism: conduction, convection, and mechanical
 energy. Conduction cooking is produced by the thermal energy from the
 barrel of the extruder. Convection cooking is caused by the addition of
 steam or other heated gases into the extruder. Mechanical energy is
 imparted to the dough by shearing imposed on the dough through shearing
 within the extruder. Shearing generated from mechanical energy can be
 detrimental to the texture and taste of such products if the protein is
 not fully hydrated as described in the previous steps.
 The precooked dough exiting the extruder preferably has a moisture content
 of between about 16 and 35 percent. Depending on the moisture content of
 the cooked dough mixture, it may be desirable to further reduce the
 moisture content through evaporation or venting 54.
 Upon exiting the extruder, the cooked dough mixture formed 60 into a
 desired shape. This typically involves either forming the dough into a
 flat sheet or cutting the dough into individual pieces. The preferred
 shaping method depends on the desired shape of the snack food products.
 Another option for shaping the dough involves heating the dough as the
 dough exits the extruder. This causes the dough to expand as the dough
 passes through the die. The temperature of the dough as the dough passes
 through the die is preferably between approximately 215.degree. F. and
 350.degree. F.
 Once the dough is formed into a desired shape, the shaped dough is further
 cooked 70. One option for this cooking stage is passing the shaped dough
 through a dryer at temperatures of between about 100.degree. F. and
 280.degree. F. to reduce the moisture content of the dough to between
 approximately 3 and 11 percent. Alternatively, the shaped dough may be
 cooked in an oven at temperatures ranging between 280.degree. F. and
 375.degree. F. Another option is to toast or puff the shaped dough in a
 convection or high velocity hot air ovens that operate at temperatures of
 between about 375.degree. F. and 600.degree. F. Yet another option for
 processing the shaped dough is to fry the shaped in a frying bath at
 temperatures of between about 225.degree. F. and 385.degree. F.
 After the dough is completely cooked, the cooked dough may be coated 80
 with additional seasonings using processes that are known to persons of
 ordinary skill in the art. One process for coating the cooked dough
 involves applying an adhesive, such as an oil or gum emulsion, on the
 cooked dough and then applying dried, powdered seasonings.
 A preferred method of forming the snack food according to the present
 invention involves using a twin screw extruder. Using a twin screw
 extruder with the present invention permits several steps to be performed
 in a single apparatus. A schematic overview of the process for using the
 twin screw extruder is outlined in FIG. 2.
 In this embodiment, legumes 112, water 114, processing aids 116, and steam
 118 are mixed together in a hydrator 110. Hydrated legumes 122 are then
 fed into a twin screw extruder 124. The hydrated legumes then enter a
 pressurized zone 130 that causes a mixture 132 of water and soluble sugars
 to be expelled from the hydrate legumes. The pressurized zone 130 is
 created by varying the configuration of the screw and barrel of the
 extruder 124. The best results are accomplished when the screw
 configuration is designed in a manner where maximum pressures are between
 about 100 and 800 psi.
 The pressure causes the expelled water to move backward opposite of the
 flow of the hydrated legumes within the extruder. The extruder includes a
 drain compartment for removing the expelled water from the extruder. The
 expelled water is discarded, carrying with it soluble sugars and
 chemicals, including the flatulents. At this stage, the hydrated legume
 press cake has a moisture content of between about 35 and 75 percent.
 Next, the press cake passes through an evaporation zone 140 where the
 moisture content of the press cake is further reduced. In the evaporation
 zone, between about 1 and 18 percent of the water 142 remaining in the
 press cake is removed.
 The press cake is then delivered to a mixing zone 150 where the press cake
 is mixed with water and additional ingredients 152, which improve the
 taste, texture and overall nutritional value of the snack food product.
 The combination of the legume press cake, the additional ingredients, and
 water forms a dough mixture. The additional ingredients 152 are preferably
 cereal grains that are added to the legume press cake at a ratio of about
 7:3. Depending on the legumes and cereal grains used in this invention,
 the mixing zone may be heated to temperatures of greater than 100.degree.
 F.
 The dough mixture is then introduced into a cooking zone 156. In this zone,
 the ingredients in the dough mixture are more thoroughly mixed and cooked
 at temperatures of between 200.degree. F. and 450.degree. F. under
 pressure. During the mixing and cooking zones 150, 156, the moisture
 content of the dough mixture may be adjusted through evaporation 154.
 The amount of cooking desired, as well as the type of texture needed for
 the end product, can be achieved by variation of shear through dispersive
 elements as well as particle size distribution. For example, larger
 particles tend to cook less and have the low cook flavoring that is common
 to tortilla chips.
 After the cooking zone 156, the cooked dough is conveyed to a forming zone
 160. In this zone, the cooked dough may be heated to yield a direct
 expanded product by following a first flow path 162. Alternatively, the
 cooked dough may be cooled to result in a half-product that may have a
 complete cooked profile but has not been expanded when leaving the die.
 This is achieved by cooling the cooked dough below the boiling point of
 water so that moisture content of the dough does not go through a phase
 change.
 When forming the cooked dough into chips, the product is extruded through a
 slit die, such as is illustrated in a second flow path 164. This provides
 a never ending ribbon which is then cut by a rotary cutter and followed by
 drying, toasting, or a frying step.
 The next element of this process includes toasting, baking, frying or
 drying step 170. These processes are accomplished using techniques that
 are known to one of ordinary skill in the art. The addition of topical
 flavoring and seasoning 180, as well as topical coloring, can be carried
 out following the cooking step 170.
 A single screw extruder production process would have to incorporate the
 same steps and conditions outlined above, but would require the use of two
 extruders, one feeding into the other. A schematic overview of this
 process is set forth in FIG. 3.
 In this embodiment, legumes 212, water 214, processing aids 216, and steam
 218 are mixed together in a hydrator 210. Hydrated legumes 222 are then
 fed into an expeller 230, which causes a mixture 232 of water and soluble
 sugars to be expelled from the hydrate legumes.
 As the press cake is transferred to a first extruder 224, the moisture
 content of the press cake is adjusted by evaporation 242. In the first
 extruder 224, the press cake is mixed with water and additional
 ingredients 252, which improve the taste, texture and overall nutritional
 value of the snack food product. The combination of the legume press cake,
 the additional ingredients, and water forms a dough mixture. Similar to
 the embodiment illustrated in FIG. 2, the additional ingredients 252 are
 preferably cereal grains that are added to the legume press cake at a
 ratio of about 7:3. Depending on the legumes and cereal grains used in
 this invention, the mixing zone may be heated to temperatures of greater
 than 100.degree. F.
 The dough mixture is then introduced into a cooking zone 256. In this zone,
 the ingredients in the dough mixture are more thoroughly mixed and cooked
 at temperatures of between 200.degree. F. and 450.degree. F. under
 pressure. During the cooking zone 256, the moisture content of the dough
 mixture may be adjusted through evaporation 254.
 After the cooking zone 256, the cooked dough is transferred to a second
 extruder 260. In this extruder, the cooked dough may be heated to yield a
 direct expanded product by following a first flow path 262. When forming
 the cooked dough into chips, the product is extruded through a slit die,
 such as is illustrated in a second flow path 264. This flow path provides
 a never ending ribbon which is then cut by a rotary cutter and followed by
 drying, toasting, or a frying step.
 The next element of this process includes toasting, baking, frying or
 drying step 270. These processes are accomplished using techniques that
 are known to one of ordinary skill in the art. The addition of topical
 flavoring and seasoning 280, as well as topical coloring, can be carried
 out following the cooking step 270.
 The two extruder system is particularly desirable when it is desired to
 cool the cooked dough before the cooked dough passes through the die. The
 cooling of the cooked dough may also be accomplished by using a second
 forming extruder. With this configuration, the unfinished product exits
 the cooking extruder and enters the die of the cold forming extruder.
 Using a two extruder set up also permits the second extruder to have a
 larger die area. The larger die area permits products to be formed in more
 intricate shapes.
 The die pressure utilized in the process of the present invention causes
 partial or full texturization of protein in the matrix of the snack foods
 produced according to the present invention. This technique achieves a
 high level of protein elongation and matrix development. The matrix is the
 part of the snack food that is responsible for development of a high
 crunch texture, with the finished snack food chips absorbing low levels of
 fat during frying.
 Texturization of the product is also enhanced because the legumes are not
 cooked before entering the extruder. Rather, the legumes are hydrated in
 the presence of processing aids. Hydration allows the protein to behave
 differently within the extrusion system so as to produce a well developed
 matrix proximate to the die area. It is believed that the matrix
 properties are developed because the protein molecules follow a glass
 transition point within the extruder under pressure and high temperature
 without the protein molecules being damaged by high shear.
 In the process of using the present invention to form chips, the matrix is
 expanded at the die and then collapsed by the sheeting rolls. This
 technique produces snack food chips with a hard crunch as well as a light
 texture.
 In another configuration, the product is extruded into a sheet, cooked, and
 then ground. This configuration permits the product to be rehydrated and
 then mixed with other ingredients. An example is for producing tortilla
 chips containing rice in addition to beans processed according to the
 present invention.
 EXAMPLES
 The following examples are presented to illustrate the process of producing
 high-protein, high-fiber, reduced-flatulence snack food according to the
 present invention. These examples are not intended to limit the scope of
 the present invention.
 Example 1
 As a preliminary step in preparing the high-protein, high-fiber,
 reduced-flatulence snack chips according to the present invention, various
 processing aids were examined to evaluate their relative effectiveness at
 hydrating legumes. Pinto beans were used in conducting this analysis. The
 ability of the processing aids to produce legumes with a softened
 endosperm and a light color were also evaluated.
 Processing aids used in this example were acetic acid (C.sub.2 H.sub.4
 O.sub.2), sodium hydroxide (NaOH), sodium chloride (NaCl), sodium sulfate
 (Na.sub.2 SO.sub.4), sodium carbonate (Na.sub.2 CO.sub.3), sodium acetate
 (C.sub.2 H.sub.3 NaO.sub.2), potassium hydroxide (KOH), calcium carbonate
 (CaCO.sub.3), calcium hydroxide (CaOH), and calcium oxide (CaO).
 Each of the samples was prepared by placing approximately 20 grams of whole
 pinto beans into a container. A solution was prepared by dissolving the
 processing aids in approximately 200 grams of water, which was heated to a
 temperature of between about 175.degree. F. and 180.degree. F. The
 solution was then added to the container holding the pinto beans and the
 container was placed into a water bath having a temperature of between
 about 175.degree. F. and 180.degree. F. The pinto beans were then allowed
 to hydrate for approximately 30 minutes.
 After the hydration period was completed, the water was drained from the
 container and the hydrated pinto beans were placed on absorbent tissue to
 dry the surface of the pinto beans. For some of the samples, the water
 drained from some of the hydrated pinto bean samples was colored
 indicating that the water may have contained solubles that were extracted
 from the pinto beans when the pinto beans were hydrating. Extraction of
 solubles during the hydration process results in an end weight gain as a
 net weight gain compared with the solubles, which were extracted during
 hydration.
 Once the hydrated pinto beans cooled to approximately room temperature, the
 weight of the hydrated pinto beans was measured. The softness and color of
 the hydrated pinto beans were evaluated on a subjective basis and rated
 from 1 to 10, with higher numbers indicating a darker color and a more
 pliable endosperm.
 The results of the samples are reported in Table 1. CaO (Samples 21-23),
 CaCO.sub.3 (Samples 13-16), and CaOH (Samples 17-20) provided the best
 combination of hydration, softness., and color at lower concentrations.
 TABLE 1
 Final
 Weight of weight of
 Sample processing legume
 No. Processing aid aid added mixture Softness Color
 1 C.sub.2 H.sub.4 O.sub.2 1.0 ml 29.14 g 1 1
 2 NaOH 1.0 ml 40.16 g 5 8
 3 None 32.44 g 5 1
 4 Na.sub.2 SO.sub.4 2.0 g 43.01 g 4 3
 5 Na.sub.2 CO.sub.3 2.0 g 43.13 g 6 5
 6 C.sub.2 H.sub.3 NaO.sub.2 2.0 g 43.74 g 3 1
 7 NaCl 2.0 g 45.44 g 0 2
 8 NaCl 4.0 g 28.90 g 2 2
 9 KOH 1.0 g 38.56 g 6 6
 10 KOH 2.0 g 38.37 g 7 8
 11 KOH 4.0 g 39.43 g 8 9
 12 KOH 8.0 g 41.04 g 10 10
 13 CaCO.sub.3 0.5 g 30.04 g 4 1
 14 CaCO.sub.3 1.0 g 31.80 g 5 1
 15 CaCO.sub.3 2.0 g 33.07 g 6 1
 16 CaCO.sub.3 4.0 g 35.30 g 6 1
 17 CaOH 0.0 g 33.11 g 4 3
 18 CaOH 0.5 g 32.58 g 5 4
 19 CaOH 1.0 g 31.08 g 6 4
 20 CaOH 2.0 g 32.08 g 6 4
 21 CaO 0.1 g 33.78 g 7 2
 22 CaO 0.5 g 34.70 g 6 3
 23 CaO 1.0 g 35.17 g 5 3
 24 CaO 2.0 g 34.34 g 5 3
 A taste test was also performed using each of the samples. Similar to the
 softness and color evaluations, the taste of the hydrated pinto beans was
 evaluated on a subjective standard.
 Overall, the samples using CaO (Samples 21-23) and CaCO.sub.3 (Samples
 13-16) exhibited the least amount of off-flavor, along with the best
 hydration and color. While using KOH (Samples 9-12) and NaCl (Samples 7-8)
 hydrated pinto beans with the least amount of off-flavor and a desirable
 color, the KOH and NaCl samples exhibited a lesser degree of hydration.
 Example 2
 The hydrated pinto bean samples produced in Example 1 were extracted using
 a hand-held squeezing device that was capable of producing a force of
 approximately 50 pounds per square inch. Approximately 20 grams of each
 cooled, hydrated pinto bean sample were placed in the squeezing device and
 then pressure was applied to the sample to extract water therefrom. This
 squeezing device enabled each of the hydrated pinto bean samples to be
 subjected to an approximately equal force per unit area.
 The results of the extractions are set forth in Table 2.
 TABLE 2
 Weight of Weight of Weight of Color of
 Sample processing hydrated extracted extracted
 No. Processing Aid aid added legumes cake water
 1 C.sub.2 H.sub.4 O.sub.2 1.0 ml 29.14 g 1.0 g 1
 2 NaOH 1.0 ml 40.16 g 5.0 g 6
 3 None 32.44 g 5.0 g 2
 4 NaCl 4.0 g 28.90 g 2.0 g 2
 5 Na.sub.2 SO.sub.4 2.0 g 43.01 g 4.0 g 4
 6 Na.sub.2 CO.sub.3 2.0 g 43.13 g 6.0 g 6
 7 C.sub.2 H.sub.3 NaO.sub.2 2.0 g 43.74 g 3.0 g 3
 8 NaCl 2.0 g 45.44 g 0.0 g 3
 9 KOH 1.0 g 38.56 g 6.0 g 7
 10 KOH 2.0 g 38.37 g 7.0 g 9
 11 KOH 4.0 g 39.43 g 8.0 g 9
 12 KOH 8.0 g 41.04 g 10 g 10
 13 CaCO.sub.3 0.5 g 30.04 g 4.0 g 1
 14 CaCO.sub.3 1.0 g 31.80 g 5.0 g 1
 15 CaCO.sub.3 2.0 g 33.07 g 6.0 g 1
 16 CaCO.sub.3 4.0 g 35.30 g 6.0 g 1
 17 CaOH 0.1 g 33.11 g 4.0 g 2
 18 CaOH 0.5 g 32.58 g 5.0 g 3
 19 CaOH 1.0 g 31.08 g 6.0 g 3
 20 CaOH 2.0 g 32.08 g 6.0 g 4
 21 CaO 0.1 g 33.78 g 7.0 g 1
 22 CaO 0.5 g 34.70 g 6.0 g 2
 23 CaO 1.0 g 35.17 g 5.0 g 2
 24 CaO 2.0 g 34.34 g 5.0 g 2
 In most of the literature, the speed of hydration as well as the quantity
 has been correlated with the alkalinity of the solution. Varying the
 alkalinity was believed to allow the cellulose coating of the beans, as
 well as the internal walls, to relax and thereby permit water to
 infiltrate the seed. However, from the above experiment, it is evident
 that calcium plays a major role in the relaxation and hydration of the
 cotyledon cell walls, thus making the extraction more efficient.
 With the concept of niximization, carbohydrates and some proteins react
 with calcium-enriched medium at a somewhat elevate pH (7.8-8.5) and heat.
 This process results in a product that is easily workable and relaxed in
 its matrix. Because of these properties, the legumes are easily cookable
 under normal extrusion temperatures and parameters so that the product
 thereby produced has a desirable flavor that is similar to corn-based
 tortilla chips.
 Example 3
 The process set forth in Example 2 was repeated using pinto beans that were
 ground to a grit size of between about 2 and 4 millimeters. The processing
 aids used in hydrating these pinto bean samples were either a mixture of
 CaO and Na.sub.2 CO.sub.3 or a mixture of CaO and CaCO.sub.3. The results
 of the extraction tests are set forth in Table 3.
 TABLE 3
 Weight of Weight of Weight of Color of
 Sample processing hydrated extracted extracted
 No. Processing Aid aid added legumes cake water
 1 CaO 0.1 g 56.38 g 39.22 g 2
 Na.sub.2 CO.sub.3 0.5 g
 2 CaO 0.5 g 65.57 g 43.25 g 4
 Na.sub.2 CO.sub.3 0.5 g
 3 CaO 0.5 g 61.39 g 43.39 g 3
 Na.sub.2 CO.sub.3 1.0 g
 4 CaO 0.5 g 55.79 g 40.06 g 2
 Na.sub.2 CO.sub.3 1.0 g
 5 CaO 0.1 g 59.39 g 37.23 g 1
 CaCO.sub.3 0.5 g
 6 CaO 0.5 g 67.57 g 42.23 g 2
 CaCO.sub.3 0.5 g
 7 CaO 0.5 g 64.35 g 42.29 g 2
 CaCO.sub.3 1.0 g
 8 CaO 0.5 g 57.89 g 40.26 g 1
 CaCO.sub.3 1.0 g
 The results generally indicate that grinding the pinto beans produces a
 higher level of hydration than hydration performed on whole pinto beans.
 The samples also exhibited good flavor and color characteristics.
 Another point to note is that the mixture of CaO and CaCO.sub.3 (Samples
 25-28) produced a greater amount of hydration and a greater amount of
 extraction at a given concentration than the mixture of CaO and NaCO.sub.3
 (Samples 29-32).
 It was found that the pH of the solution used for hydrating the pinto beans
 did not play an important role with these samples because the processing
 aids were added at a sufficiently small concentration so that the proteins
 in the pinto beans were able to buffer the solution to a desired extent.
 Example 4
 The process of the present invention was evaluated for producing snack
 chips from kidney beans. The kidney beans were initially ground to a
 particle size of between about 2 and 4 millimeters. Each of the samples
 was prepared using approximately 100 grams of ground kidney beans that
 were submerged in approximately 250 grams of water along with the
 designated concentrations of processing aids. The concentration of the
 processing aids was calculated based on the weight of the raw kidney bean
 material used.
 The ground kidney bean solution was maintained at a temperature of between
 about 175.degree. F. and 180.degree. F. for about 20 minutes to permit the
 kidney beans to hydrate. After the hydration period was completed, water
 was drained from the kidney beans and the weight of the hydrated kidney
 beans was measured.
 Water was extracted from the hydrated kidney beans using the extracting
 device and process described in Example 2. The press cake was then
 evaluated for color, taste, and overall appearance. The press cake was
 then formed into a sheet, cut into pieces, and fried so that the texture
 of chips produced according to the present invention could be evaluated.
 The results of these samples are set forth in Table 4. The color and taste
 of the press cake as well as the taste of the chips were evaluated on a
 scale of 1 to 10 with lower values indicating a lighter color and less
 off-flavor. The results indicate that the addition of calcium in the form
 of oxides, hydroxides, or carbonates produces an end product (chips) with
 desirable taste and appearance characteristics. In particular, the results
 display that the use of CaO, CaCO.sub.3 and/or CaOH at concentrations of
 between about 0.01 percent and 5.0 percent and with a total processing aid
 concentration of not more than about 10 percent enable chips to be
 produced with desirable characteristics.
 TABLE 4
 Concen- Weight Color/
 tration of of Weight taste of
 Sample Proces- processing hydrated of press press Taste of
 No. sing aid aid legumes cake cake chip
 1 CaO 0.5% 283.9 g 271.5 g 1/2 1
 CaCO.sub.3 5.0%
 CaOH 0.1%
 2 CaO 1.0% 327.9 g 216.5 g 1/1 2
 CaCO.sub.3 5.0%
 CaOH 0.1%
 3 CaO 2.0% 329.9 g 219.5 g 1/2 2
 CaCO.sub.3 5.0%
 CaOH 0.1%
 4 CaO 0.5% 310.8 g 216.8 g 1/1 1
 CaCO.sub.3 5.0%
 CaOH 0.05%
 While the chips produced in this example did not include cereals or other
 raw materials, the press cake properties and the chip properties indicate
 that chips having a light color and little or no off-flavor can be
 produced according to the present invention. Cereals and other raw
 materials may be added to the press cake to provide the chips with an
 amino acid profile, which is similar to meat protein, as well as to
 provide vitamins and other nutrients that may have been removed from the
 legumes during the processing operations. However, an important point to
 note is that the most essential components of the legumes are retained in
 the process of the present invention, namely, the protein and fiber
 content that is present in the hull and cotyledon portions of the legume.
 Although the present invention has been described with reference to
 preferred embodiments, workers skilled in the art will recognize that
 changes may be made in form and detail without departing from the spirit
 and scope of the invention.