1. Technical Field
The present invention relates to a method for making an extruded legume snack food and, more particularly, to a method for making an extruded legume snack that meets specific nutritional goals and has a final shape that is characteristic of the starting material in its natural state.
2. Description of Related Art
Legumes, which are also known as dried beans and pulses, are the edible seeds that grown in pods on annual plants, bushes, or vines of the leguminosae family. The seeds can be eaten fresh, sprouted, dried and ground into flour, or prepared in other ways by cooking the legumes. Legumes are often cooked in combination with grains because, when the amino acids contained in the grains and legumes are combined, they provide a complete protein source.
Legumes are a good source of protein and can be a healthy substitute for meat, which has more fat and cholesterol. Legumes are typically low in fat, contain no cholesterol, and are high in protein, folate, potassium, iron, and magnesium. They also have phytochemicals, a group of compounds that may help prevent chronic diseases, such as cardiovascular disease and cancer. In addition, they are an excellent source of fiber, and a diet high in fiber can reduce the risk of developing diabetes and help lower blood cholesterol levels, which in turn reduces the risk of heart disease.
There is a wide variety of legumes consumed by humans. Several of the more common types include black beans, black-eyed peas, chickpeas (garbanzo), fava or broad beans, lima beans, navy beans, peas, pinto beans, soy beans, and red kidney beans.
Consumers have recognized that legumes are an important part of a healthy diet. Consumer studies show that a puffed legume based snack with good nutritional values is a desirable product.
The production in the prior art of a puffed extruded product, such as snacks produced and marketed under the Cheetos™ brand label, typically involves extruding a corn meal or other dough through a die having a small orifice at high temperature and pressure. The dough flashes or puffs as it exits the small orifice, thereby forming a puff extrudate. The typical ingredients for the starting dough may be, for example, corn meal of about 41 pounds per cubic foot bulk density and 11 to 13.5% water content by weight. However, the starting dough can be based primarily on wheat flour, rice flour, soy isolate, soy concentrates, any other cereal flours, protein flour, or fortified flour, along with additives that might include lecithin, oil, salt, sugar, vitamin mix, soluble fibers, and insoluble fibers. The mix typically comprises a particle size of 100 to 1200 microns.
The puff extrusion process is illustrated in
While inside the die assembly, the viscous melt 10 is subjected to high pressure and temperature, such as 600 to 3000 psi and approximately 400° F. Consequently, while inside the small orifice 14, the viscous melt 10 exhibits a plastic melt phenomenon wherein the fluidity of the melt 10 increases as it flows through the die 12.
It can be seen that as the extrudate 16 exits the orifice 14, it rapidly expands, cools, and very quickly goes from the plastic melt stage/phase to a glass transition stage/phase, becoming a relatively rigid structure, referred to as a “rod” shape if cylindrical, puffed extrudate. This rigid rod structure can then be cut into small pieces, further cooked by, for example, frying, and seasoned as required.
Any number of individual dies 12 can be combined on an extruder face in order to maximize the total throughput on any one extruder. For example, when using the twin screw extruder and corn meal formulation described above, a typical throughput for a twin extruder having multiple dies is 2,200 lbs., a reasonable industrial production rate of extrudate per hour, although higher throughput rates can be achieved by both single and twin screw extruders. At this throughput rate, the velocity of the extrudate as it exits the die 12 is typically in the range of 100 to 400 feet per minute, but is dependent on the extruder throughput, screw speed, orifice diameter, number of orifices and pressure profile.
As can be seen from
Aside from the shape issue, ideally, such extruded legume snack should meet certain nutritional guidelines formulated to meet specific health or wellness benefits. Along these lines, it is desirable to have a nutritious snack that contains, per one ounce serving, no more than 5 grams of fat, that is low in saturated fat, has 0 trans-fatty acids, has less than 25% calories from added sugar, and no more than 240 mgs. sodium.
Consequently, the need exists for a method for making an extruded legume product with specific nutritional formulations that has a final shape that is characteristic of the starting material. For example, a need exists for an extruded pea based snack food that has a final appearance of a pea pod.
The present invention is a method for producing an extruded legume snack having a final shape that is characteristic or representative of the legume ingredient used in the product. In one embodiment of the invention, green pea powder is mixed with rice flour and fed into an extruder. The extrudate is subsequently formed into the shape of a pea pod by one of several alternative embodiments. In one embodiment, the extrusion die is shaped such that pea pod shapes can be cut from the exiting extrudate. In another embodiment, the extrudate is formed into a hollow tube and then stamped and cut into a pea pod shape. In yet another embodiment, the extrudate exits the extruder as a solid cylindrical shape and is then stamped and cut into a pea pod shape. The end result of this preferred embodiment is a nutritious legume based snack product that resembles a pea pod shape, thus providing the consumer with positive reinforcement of the primary starting ingredient.
These as well as additional features and advantages of the present invention will become apparent in the following written description.
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:
The admix is then extruded 208. This extrusion is typically a flash extrusion such that the product emerges as a puffed extrudate going quickly from the plastic melt stage to a glass transition stage. The velocity of the extrudate as it exits the extruder is in the range of about 50 feet per min to about 200 feet per minute, which Applicants define as a “high velocity discharge.” In one embodiment, the velocity of the extrudate as it exits the extruder is in excess of 100 feet per minute. This high velocity discharge is most preferably in the range of 120 to 200 feet per minute. In another embodiment, the velocity of the extrudate as it exits the extruder is about 50 feet per min to about 100 feet per minute. The extrudate is extruded at a rate of about 110 kilograms per hour.
In one embodiment of the invention, the extrudate is shaped by the extrudate die itself and forms a facsimile of a pea pod shape when the extrudate is cut as it exits the extruder die. In an alternative embodiment, the extrudate is fed into a shaping or forming device, as will be explained in more detail below, in order to accomplish a shaping and cutting step 210. The purpose of this alternative embodiment shaping and cutting step 210 is to likewise form the extrudate into individual pieces having similar shape characteristics (a similar appearance) to the legume product that is the basic material of the dry mix.
In any event, once the extrudate has been cut into individual pieces either in the extrusion step 208 or the shaping step 210, each individual piece can be dried, if needed to obtain a desirable texture, and then optionally seasoned by means known in the art, such as a seasoning tumbler, seasoning curtain, or sprayed-on seasoning oil. It should be understood that this seasoning step 212 is an optional step and may not be necessary depending on the desired end product.
Finally, the legume snack pieces are packaged 214, typically in a flexible bag by, for example, a vertical form, fill, and seal machine. Once the packaging step 214 is complete, the legume snack pieces are ready for retail sale and consumption by the public.
The extruded snack of the present invention is high in vegetable (legume) content. The nutritional goals for the snack of the present invention include a per-ounce serving of snack chips with no more than 5 grams of fat, less than 1 gram of saturated fat, 0 trans-fatty acids, less than 25% added sugar, and no more than 240 mg. sodium.
In one preferred embodiment, the extruded snack of the present invention incorporates at least ⅓ “serving of vegetables” per 1 ounce serving of the snack product (as defined further below). In another preferred embodiment, the extruded snack of the present invention incorporates at least ½ serving of vegetables per 1 ounce serving of the extruded snack. In yet another preferred embodiment, the extruded snack of the present invention incorporates at least 1 serving of vegetables per 1 ounce serving of the snack product.
The United States Department of Agriculture (USDA) defines a serving of vegetables as ½ cup of chopped vegetables. For example, ½ cup of 1 inch cubes of raw pumpkin constitutes 1 serving of pumpkin, and ½ cup of chopped or sliced raw tomatoes constitutes 1 serving of tomato under the USDA guidelines. A serving of vegetables can be understood as having a moisture content and a solids content. Vegetable solids are defined herein as the non-water components of vegetables. Thus, a serving of vegetables comprises a vegetable solids content on a dry basis. The USDA National Nutrient Database for Standard Reference defines the weight of the edible portion of a vegetable in that ½ cup and defines the average moisture and thus the vegetable solids content of the edible portion of a vegetable. Table 1, for example, depicts the nutrient profile for 1-cup or 180 grams of a red, ripe, raw, year round average tomato as accessed at http://www.nal.usda.gov/fnic/foodcomp/search/.
As used herein, a “serving of vegetables” is defined as the amount of vegetable solids content that is equivalent to ½ cup (118 cubic centimeters) of vegetables on a dry basis based on the USDA National Nutrient Database for Standard Reference, Release 19, 2006, which is incorporated herein by reference. According to Table 1, one cup of red, ripe, raw, year round average tomatoes weighs 180 grams, has a water content of 94.5% by weight and a vegetable solids content of 5.5%. One vegetable serving of raw tomatoes (½ cup) has a total weight of 90 grams. Consequently, 4.95 grams (5.5% solids content×90 grams total weight) of tomato solids in a finished product is equivalent to one serving of vegetables. (As known to those skilled in the art, vegetable powders typically have an intrinsic moisture component, e.g., tomato powder is 5% moisture by weight. Consequently, the amount of tomato powder needed for one serving of vegetables may not exactly correspond to the amount of tomato solids needed for one serving of vegetables.) Thus, a snack product having a one-third vegetable serving of tomato would have approximately 1.65 grams of tomato solids in a 1 ounce serving of snack product, a snack having a one-half vegetable serving of tomato would have approximately 2.48 grams of tomato solids in a 1 ounce serving of snack product, and a snack having one vegetable serving of tomato would have approximately 4.95 grams of tomato solids in a 1 ounce serving of the snack product. Consequently, in one embodiment, vegetable or legume powder can be added in an amount sufficient to provide for a one-third vegetable serving, in a preferred embodiment in an amount sufficient to provide for a one-half vegetable serving, and in another preferred embodiment in an amount sufficient to provide for one vegetable serving. As previously noted, one serving of vegetables is defined as the amount of vegetable solids that is equivalent to ½ cup (118 cubic centimeters) of a chopped vegetables on a dry basis based on the USDA National Nutrient Database for Standard Reference, Release 19, 2006, which is incorporated herein by reference, it being understood that in this context the terms “vegetable” and “legumes” are used interchangeably.
In a preferred embodiment, green pea powder is mixed with rice flour in a ratio of preferably 50% to 75% by weight pea powder and the remaining substantially by weight of rice flour, with a most preferred range of about 65% by weight green pea powder and about 35% by weight of rice flour. Examples of acceptable pea powder starting ingredients include green pea flakes manufactured by Quest International Fruit and Vegetable Products of Silverton, Oreg., or drum-dried instantized pea flakes manufactured by Van Drunen Farms of Momence, Ill. An acceptable rice flour can include RF-L0080 rice flour manufactured by Sage Foods of Los Angeles, Calif. This drymix is fed into a single screw extruder and water is added in order to bring the moisture level of the mixture to between about 15% to about 25% by weight. This hydrated admix is then subjected to work in the extruder through heated barrels of sequentially increasing temperature, typically starting at 80° F. and finishing at 320° F. The residence time for the admix in the extruder typically is between 20 and 40 seconds, and the extrudate exits the extruder at approximately 305° F. to 340° F.
The preferred embodiment of pea powder and rice flour described above meets all of the nutritional guidelines previously stated and, further, equates to a ½ serving of vegetables per 1 ounce serving of the snack product. Ideally, this product in its final form should also have a shape that resembles the starting material on which the product is based. Stated another way, the finished product should have an appearance associated with the legume starting material. By way of example, a product based on pea powder can be shaped like a pea pod. By way of another example, a product based on peanut material can be shaped like a peanut pod, and so forth.
After the extrudate 311 exits the forming device 310, the finished shape of the molded product 313 is exhibited. The forming device 310 can also cut the final shape 313 into individual segmented pieces. There are several different pieces of equipment that can be used as the forming device 310 in accordance with Applicants' invention, as will be discussed further below.
In an alternative embodiment, the extrudate 311 is stretched as it exits the extruder 308 by, for example, a forming device 310 operating at a slightly higher speed than the discharge rate of the extrudate 311. This stretching step prior to the forming/shaping step must again be done prior to the extrudate cooling to below the glass transition temperature, but before the post-extrusion forming/stamping into a legume or pea pod shape. Performing this stretching step provides for different texture characteristics in the end product as opposed to not stretching the extrudate 311. Further, the stretching step can be used to narrow the diameter of the extrudate rope 311 prior to entering the forming device 310 as a part of the shaping step.
In one embodiment of Applicants' invention, the extrudate stream 311 is extruded as a hollow tube, or in a tubular shape, as opposed to a solid rod shape. Extruding a tubular extrudate 311 provides for the trapping of water vapor and heat inside the tube during shaping, thus making the tube more malleable during forming. This can be further understood with reference to
After being cut, the extrudate 411 is then subjected to the physical manipulation of opposed shaping pads 418, which pinch the extrudate, without cutting it, such that opposed walls of the tubular extrudate mate. This can be best shown by the cross-sectional view of the formed pea pod shaped product illustrated in
It should be understood that the forming roller embodiment illustrated by
In a preferred embodiment, the forming rollers 409 can comprise opposed molds in which the extrudate is molded, versus pinched, as it shown in
Referring again to
Another embodiment of the forming device 310 of
While it should be understood that the Applicants' forming technology has been explained in relation to the formation of a pea pod shape, the same principles can apply to the shapes of other legume and vegetable shapes, such as a peanut pod, whole carrot, broccoli florets, bean pods, or corn stalks shapes.
Although Applicants' invention has been described specifically with regard to a process for extruding peas, it should be understood that the concepts of Applicants' invention can be applied to any number of legumes, including, without limitation, chickpeas, lima bean, kidney beans, red beans, peas, pinto beans, black-eyed peas, black beans, soy beans, navy beans, mayocoba beans, or cranberry beans. Portions of Applicants' invention also have application to vegetables in general.
This application is a continuation-in-art application of co-pending U.S. patent application Ser. No. 11/696,023, entitled “Extruded Legume Snack Food,” filed Apr. 3, 2007, the technical disclosure of which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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Parent | 11696023 | Apr 2007 | US |
Child | 13826697 | US |