CRISPED PROTEIN FOOD PRODUCT

Abstract

A crispy, proteinaceous food product is described in which egg white proteins constitute the majority of the total protein present. The food product has a bulk density of 120 to ~500 g / L and includes water, expanded starch, and denatured proteins. Ovalbumin constitutes at least 33% (w / w) of the protein. Expanded starch may constitute at least 35% (w / w) of the food product.

Description

Crispy Protein Food Product Background Information Crunchy protein products have been prepared from dairy products and a variety of vegetables, including soybeans, rice, peas, quinoa, sorghum, and similar grains. These crunchy food items have then been incorporated into snack bars, cereals, baked goods, and other products. In recent years, soy crisps have gained popularity due to consumer demand for protein and snack bars, and the relatively good bioavailability of soy protein. However, soy protein crisps often need to be masked with a strong flavor (e.g., chocolate and / or peanut butter) due to unpleasant tastes resulting from the presence of chemicals such as aldehydes, benzoates, furans, n-alkanols, geosmin, and chlorogenic acid. Bird eggs, particularly chicken eggs, have been a staple food for centuries. Over time, different uses have emerged for egg whites and yolks. Egg white, also known as albumen, is the alkaline liquid portion of the egg that surrounds the yolk. It makes up approximately two-thirds of a chicken egg by weight. Egg white contains 10-12% (w / w) protein. Slightly more than half of an egg's protein content, but very little of its fat content and no cholesterol, is found in the egg white. Advantageously, the egg white is free of many of the organic compounds responsible for the unpleasant flavors mentioned above, which must be masked with sugar, additives, or strong-flavored coatings. Nearly 150 egg white proteins have been identified, including, for example, ovalbumin, ovotransferrin, ovomucoid, ovoglobulin G2 and G3, ovomucin, lysozyme, ovoinhibitor, ovoglycoprotein, flavoprotein, and ovomacroglobulin. To date, the most prevalent protein in egg white is ovalbumin. Advantageously, egg white protein is highly bioavailable, much more so than the protein available from many other sources including, for example, soy. However, the nature of the proteins in egg white has inhibited their use in the production of the types of crispy products described above. If the extrusion techniques commonly used in the manufacture of soy protein crisps are used with egg white protein, the extruder becomes clogged or, failing, a textured protein (rather than a crispy product) would result. United States Patent Publication No. 2009 / 0220674 describes an expanded food product made from egg white. The resulting expanded food product has been described at a density of less than 100 g / L, which is well below that required for many end-use applications such as protein and nutrition bars where expanded food products with greater firmness and crispness are used. What remains desirable is a crispy food product made from egg white protein and a method for providing such a food product. BRIEF DESCRIPTION The present document then describes a crunchy proteinaceous food product in which egg white proteins constitute the majority of the total proteins present. In one aspect, a proteinaceous food product is provided that has a bulk density of ~120 to ~500 g / L. The food product includes water, expanded starch, and denatured proteins. Ovalbumin constitutes at least 33% (w / w) of the proteins. In some embodiments, expanded starch may constitute at least 35% (w / w) of the food product. In another aspect, a process is provided for zc / rnn / Lznz / E / YiAi to provide a proteinaceous food product that has a crispy texture and a higher degree of firmness than that previously obtainable. The proteinaceous product can be consumed as is or can be used as an ingredient in a processed food item, for example, a protein or nutrition bar. Unless a portion of the text specifically indicates otherwise, all percentages throughout this document are percentages by weight, i.e., w / w. The more detailed description and figures that follow provide further details that explain and illustrate the processes described above. The appended claims define the inventions in which exclusive rights are claimed and are not intended to be limited to the particular embodiments shown and described, of which persons ordinarily skilled may contemplate variations and additional aspects. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents a simplified schematic representation of the screws of a twin-screw extruder, not to scale with the protective barrel removed, which can be used in the production process described herein. FIG. 2 is a graph of texture analyzer data (force vs. time) showing ruptures of zc / rnn / Lznz / E / YiAi expanded starch cells in an exemplary crispy proteinaceous food product according to the present invention. DETAILED DESCRIPTION OF ILLUSTRATIVE MODALITIES As briefly described above, this paper describes high-protein extruded products and methods for making such extruded products. Extruded products are useful because they offer a high-protein product, even in a form typically associated with high-carbohydrate products. A high-protein product is one that provides at least 20% of the Daily Value (DV) for that nutrient. Since the DV for protein is 50g, a high-protein product needs to provide at least 10g of protein per serving. Medium-density breakfast cereals (20-43g / cup) and many snack foods (potato chips, snack mixes, extruded snacks, etc.) have a serving size of 30g, meaning they must contain 33% (w / w) protein to be labeled as high-protein. In the description that follows, a proteinaceous food product that has a crunchy texture is referred to as a crunchy product. The processes and equipment used to make crispy products from a variety of protein sources are well-established. The ingredients are fed into an extruder where they are mixed, moistened, heated under pressure, passed through a die, and cut. Many extruders are capable of performing these steps, so little or no pre- or post-processing is required. Various components associated with the extruder can grind, hydrate, cut, homogenize, mix, compress, and degas the ingredients fed into the extruder. Extrusion can involve the melting and / or plasticizing of certain ingredients, starch gelatinization, and protein denaturation, with the necessary heat resulting from a variety of sources such as steam injection, external heating of the extruder barrel, or introduced mechanical energy. By varying processing conditions and dies, extrusion can produce food products with little expansion (e.g., pasta), moderate expansion (e.g., formed breakfast cereal, textured soy (i.e., meat substitute), corn starches, pet food, etc.), or significant expansion (e.g., puffed cereal or snacks); crispy products fall into the latter category. When the pressurized extruded material exits the extruder barrel and encounters reduced pressure and temperature, it expands and cools, resulting in an inflated product. The inflated product can have different shapes and sizes, depending on the die it passes through and the cutting frequency. Subsequent drying can result in a food product moisture content of approximately 1% to 8%, preferably no more than 5%, and ideally no more than 3%. For additional information on the production of crunchy protein products, the interested reader is directed to any of a variety of publications including KE Alien et al., Influence of protein level and starch type on an extrusion-expanded whey product, Intl. J. Food Sci. and Technol., 42, 8, pp. 953-60 (2007), HF Conway et al., Protein-Fortified Extruded Food Products, Cereal Science Today, 18, 4, pp. 94-97 (1973), and L. Yu et al., Protein rich extruded products prepared from soy protein isolate-com flour blends, LWT Food Sci. Technol., 50: 1, pp. 279-89 (2013); texts such as C. Mercier et al., Extrusion Cooking (Am. Assn of Cereal Chemists, 1989) and L. Moscicki (ed.), Extrusion-Cooking Techniques (Wiley-VCH, 2011); and patent documents such as U.S. Patent Publications Nos. 2007 / 0077345, 2008 / 0102168, 2015 / 0296836 and the like. Unfortunately, the conditions used to make crispy products from the most widely used plant proteins (e.g., soy) do not produce crispy products when egg white proteins are used instead. Specifically, generally accepted processing conditions result in undesirable configuration and / or association of egg proteins in the extruder, preventing the formation of a crispy product. The knowledge gained from making crispy products from soy protein does not directly translate to the manufacture of crispy products from egg protein. The ratio of primary dry ingredients, the amount of water added to the dry ingredients in the extruder, and the amount of energy (both thermal and mechanical) introduced into the mixture while it is in the extruder all impact the ability to obtain a crispy proteinaceous food product with the desired volume density. The following paragraphs describe a set of conditions that can be used with a twin-screw extruder to produce crispy egg protein products. These exemplary conditions can be adjusted to suit the available equipment and specific desired end-product characteristics. The preferred dry ingredients are mixed before being introduced into the extruder. This typically occurs at or near room temperature. No special mixing equipment or techniques are required. zc / rnn / Lznz / E / YiAi Two required dry ingredients are dried egg whites, preferably egg white powder, and starch. Egg white powder is a form of dried egg whites, a food product that is regulated in the United States; see 21 CFR § 160.145. Both dried egg whites generally and egg white powder specifically are commercially available from a variety of sources. The second required dry ingredient, starch, can be derived from a variety of sources, including, but not limited to, corn, rice, potatoes, wheat, and tapioca. Alternatively, a food product containing a high amount of starch, such as certain wheat and corn flours, can be used instead of or in addition to the starch itself. Mixtures of different starches and / or starchy food products are also acceptable. The type of starch or starch-containing product can impact the organoleptic properties of the resulting extruded food product, and experienced food chemists can typically adjust the choice and quantity of various starches or starchy products accordingly. The ratio of dried egg white (egg white powder) to starch(es) generally ranges from 1:3 to 3:1, frequently from 1:2 to 2:1, and commonly from 2:3 to 3:2. In some formulations, the amount of dried egg white (or egg white powder) constitutes at least 50% (w / w) of the sum of the egg-based and starch-based components. (The above ingredient ratios and percentages also apply to the final product.) Additional dry ingredients may be included in the mix and / or added at a later stage of processing. Examples of additional dry ingredients include one or more other protein types (including, but not limited to, soy, casein, whey, pea, rice, and wheat protein), fatty acids, flavorings and sweeteners, spices and seasonings, texture modifiers (e.g., calcium carbonates), minerals (e.g., calcium sulfate, sodium carbonate, and potassium carbonate), vitamins, mono- and diglycerides, lecithin, inulin, and fiber. The amounts of such additional dry ingredients can vary greatly, although less than 5% (w / w) is preferred. Dry ingredients typically have a light, fluffy, powdery consistency. The dry ingredient mix is ​​fed into the extruder, typically by gravity from a hopper, although these ingredients can optionally be conveyed through a preconditioner depending on the extrusion system configuration. (During this conveying, no water is added; that is, the preconditioner is solely a conveying device.) Additional dry ingredients such as zc / enn / Lznz / E / YiAi can also be introduced into the extruder here (using separate ingredient feeders, if necessary), regardless of whether the same or other additional dry ingredients were included in the initial mixing stage. A simplified schematic representation of the screws of an exemplary extruder that may be used is shown in FIG. 1. Extruder 10 includes screws 12 and 14. (Representations of flights have been omitted from the barrel for clarity, although a person of average skill understands how the areas described below employ flights of different shapes, depths, frequency, and the like.) In the particular configuration shown in FIG. 1, each of screws 12 and 14 includes the same sections, which is common. The part numbers are shown in connection only with screws 12 and 14, although a person of average skill would understand that the sections shown apply to both screws 12 and 14. The initial transport section 20 serves to draw the dry ingredients away from the feeder orifice and into the extruder body. A long-space configuration is preferred to perform this type of transport at a sufficient speed. Water, as well as other optional liquids such as dyes, oils, and the like, can be added in an initial transport section 20, very shortly after the introduction of the dry ingredients. Pressurizing these liquids (or at least the water) allows them to be introduced through a nozzle at an essentially constant rate. The liquid(s) do not need to be heated or cooled before introduction, although these options are not excluded. After the initial conveying section 20, the depicted design includes the forward conveying sections 22 separated by the first kneading section 24 and the second kneading section 26. The combination of these conveying and kneading sections preferably constitutes 65-85% of the screw lengths 12 and 14. The ratio of the conveying and kneading zone lengths is typically at least 2:1. The use of cutting screws, which allow the solids to slide backward, frequently results in crispy products with unacceptable amounts of undesirable texturizing, and is therefore preferably avoided. The dry ingredients are transported in and along the barrel, during which time they receive relatively low amounts of mechanical energy introduced by all the initial portions of screws 12 and 14, i.e., the transport and kneading sections. The distant section 28 of screws 12 and 14 zc / enn / Lznz / E / YiAi pushes the mass through, typically, through the cone screws. Both compression and final transport occur here. Given the relatively moderate die temperature targets mentioned below and the natural temperature rise due to the mechanical energy imparted by the screws, little or no barrel jacket heating is required. Each surrounding barrel jacket section is typically maintained at approximately room temperature, i.e., 15° to 30°C, and the introduction of additional thermal energy from an external source (e.g., barrel jacket heating) is typically avoided. The rear barrel sections may be heated slightly, but typically no more than ~30°C, while the last barrel section is preferably kept below 30°C, typically ~25°C. Despite the lack of thermal energy introduced from an external source, the extruded contents typically experience a temperature rise due to the conversion of mechanical work to heat from approximately ambient temperature in the initial transport section 20 to ~100°C or thus the distant section 28. The ratio of the screw length to the inner diameter of the extruder barrel is at least 12, preferably at least 16, and much more preferably at least 20. The extruder screw speed can vary from 200 to 600 rpm, with the specific speed depending largely on the extruder type and design and the desired output. (Both the minimum and maximum speeds in the preceding sentence have a tolerance of +10%). For comparison, processes used to make soy crisps (i.e., crispy products made solely from soy protein) typically employ a screw speed of no more than 120–130 rpm, commonly around 100 rpm. Crispy products with good organoleptic properties can be obtained, without extruder clogging, using approximately 10-20% (w / v) water, for example, 10-20 L of water per 100 kg of dry ingredients. Lower ratios (e.g., from ~2 to less than 10 L, typically less than 8 L, of water per 100 kg of dry ingredient) can be used to good effect, although at the risk of a less stable process where slight variations in tolerance runs carry the risk of extruder clogging. In the early stages of a given extrusion, the above ratios can be adjusted upwards, for example, to 25–100 L, 30–90 L, or even 35–80 L of water per 100 kg of dry ingredients. As the extruder barrel fills and the temperature of its contents increases to approximately 80°C, the liquid introduction rate can be reduced to provide the ratios mentioned above. The water quantities mentioned above are higher than those typically used when making crispy plant-based protein products; in other words, a higher moisture level is required initially to start the extruder and hydrate the proteins in this process than is required in a similar process with plant proteins. Once the extruder has reached a steady state, similar amounts of water can be used to achieve good expansion, although extrusion processes involving plant proteins are less likely to clog when using lower amounts of water. The ratio of liquid to dry feed also impacts operating pressures, with higher ratios resulting in lower pressures and lower ratios resulting in higher pressures. An exemplary target extruder operating pressure range is 10 to 12.5 MPa (approximately 1500 to 1800 psi), assuming the equipment is rated for such pressures. This range applies to a wide range of extruders, including models manufactured by Wenger (Sabetha, Kansas) and Baker Perkins Ltd. (Peterborough, UK). The temperature of the material exiting the zc / rnn / Lznz / E / YiAi die is preferably at least ~100°C, more preferably at least ~105°C, even more preferably at least ~110°C, but preferably no more than ~165°C, commonly no more than ~160°C and typically no more than ~150°C. (Any of the above minimums may be combined with any of the maximums to provide preferred ranges). Die sizes and shapes can vary depending on the desired end shape and size of the protein crisp. In practice, a larger die diameter (e.g., 4 mm) is generally associated with slightly better texture and expansion, perhaps due to less constriction / shear stress on the material. Dies ranging from 0.5 mm slots to 4.0 mm circles have produced acceptable products. If a cutting device is not used, the extruded material comes out in the form of a string. Using string-cutting segments on the workpieces creates spheres, oblong cylinders, and similar shapes. The end-use application drives the shape of the cutting device and its frequency. Extruded material typically has a moisture content of 10 to 25% (w / w), which is higher than desirable. Heating to remove moisture (drying) can reduce the moisture content to less than 5% (w / w), preferably no more than 4% (w / w), and ideally no more than 3% (w / w). If an oven is used for this drying stage, its temperature can be maintained between 82° and 93°C (~190° ± 10°F), which promotes dehydration rather than cooking. The resulting protein crisps typically include, on a moisture-free basis, ~22.5 to ~55%, preferably ~24% to ~54%, and more preferably ~25% to ~52.5% protein and ~25 to ~77%, preferably ~27.5% to ~75%, and more preferably ~30% to ~72.5% carbohydrates (all w / w). (The vast majority of the carbohydrates, and in some cases all of them, result from the starch(es) mentioned.) Ash always accounts for at least a small amount of mass in the final product, so that matching the respective ranges for protein and carbohydrate typically does not result in a sum of 100%. However, any of the first set of intervals can be combined with any of the second set to provide combined percentage intervals, on the condition that the sum of the two percentages cannot exceed 100%. For points of comparison, typical values ​​for a variety of crunchy protein products are shown below in Table 1. Table 1: Common percentages of protein and carbohydrates in crispy products I Protein I Carbohydrate zc / rnn / ίζηζ / Β / γι Lentils 25 63 Peas 27 72 Corn 8-9 86 Rice 6 88 Milk (fat-free, dry) 45-85 15-55 Soy concentrate / isolate 80-90 10-20 Soy flour, full fat 32-67 33-68 Soy flour, low fat 50 30 zc / enn / Lznz / E / YiAi Advantageously, the process described above can produce a protein crisp where all or a substantial portion of the protein is egg protein. At least 33%, preferably at least 35%, more than 5% preferably at least 37.5%, even more preferably at least 40%, still more preferably at least 42.5%, still more preferably at least 45%, still more preferably at least 47.5%, and much more preferably at least 50% (all w / w) of the protein in the crisp is ovalbumin. The process described above also produces a proteinaceous food product that has a volume density that is higher than that of the process described in United States Patent Publication No. 2009 / 0220674 15 Al. The resulting protein crispy product has a volume density of ~120 to ~500 g / L. Some end-use applications require crunchy protein products with a specific bulk density, or at least a bulk density within a relatively narrow range. For example, many dry breakfast cereals have bulk densities in the range of 120 to 275 g / L, with some specialty cereals (e.g., muesli) having even higher densities, e.g., 350 to 400 g / L. Crunchy snacks have bulk densities in the range of 130 to 190 g / L, while bread rolls are much higher (e.g., ~450 g / L). An extruded product intended for such an application must have a corresponding bulk density value. Advantageously, the process described above can provide crispy protein products having volume densities of at least 125, at least 130, at least 140, at least 150, at least 160, at least 170, at least 180, at least 190, at least 200, at least 210, at least 220, at least 225, at least 250, at least 275, at least 300, at least 325, at least 350, at least 375, at least 400, at least 425, at least 450, and at least 475 g / L. (Also contemplated are ranges that use one of the above minimums with another minimum that is higher than the first). This range allows the resulting protein crisps to be adapted to match (or replace) a wide variety of food products currently in use. Before use or packaging, preferably dry crispy products are cooled to close to room temperature. The preceding description has employed certain terms and phrases for the sake of brevity, clarity, and ease of understanding; unnecessary limitations will be implied by them because such terms are used for descriptive purposes and are proposed to be widely considered. The compositions and methods described above have been presented as examples only. Certain features of the described compositions and methods may have been described in connection with only a few of these compositions or methods, but should be considered useful in other compositions or methods unless their structure or use is capable of adaptation for additional use. Combinations of features described in isolation are also contemplated. The relevant portion(s) of any patent or publication specifically mentioned in the preceding description are incorporated herein by reference. EXAMPLES The bulk density of a solid food product can be measured by filling a container of known volume zc / enn / Lznz / E / YiAi (e.g., laboratory beaker, measuring cup, etc.) with that product, ensuring that the product does not bend at the top of the container (i.e., leveling of the top surface), measuring the weight of the food product 5, and dividing the weight by the known volume. The above procedure was used to compile crispy egg protein products, made according to the production method described above, which have a range of volume densities. These products are shown in Table 2. Table 2: Crispy products with tested protein Sample Density in volume (g / L) 1 (comp.) 90 2 150 3 175 4 220 5 280 6 340 7 410 Each of the egg protein crisps listed in Table 2 was analyzed for its textural properties, specifically crispness and firmness. The test was performed using a stable texture analyzer. Micro Systems equipped with a 40mm wide compression plate and 12mm deep cavity attachment. One gram of crispy protein product was fed into the cavity below the compression platen before the platen was allowed to descend and compress the sample. Once an actuating force was reached (set to 100 g in these tests), the analyzer recorded the force, vertical distance, and time until the measured force reached the maximum setting (50 kg for this test). The above was done 5 times for each sample. An exemplary output from one of these tests is shown in Figure 2, where force is plotted against time. Each dip represents the rupture of the expanded starch cell of a crispy product, with the number of peaks per unit time considered a measure of overall crispness capacity; that is, a crispier sample has more bursts than a less crispy sample. The amount of time required to reach the endpoint force, i.e., to compress the sample, is considered an indicator of the sample's firmness, with softer samples taking longer to reach that point than harder samples. The number of cracks in each of the collected runs was plotted against the calculated volume density. Standard regression analysis of the plotted data indicated a correlation between volume density and zc / enn / Lznz / E / YiAi crispness capacity. Firmness (in g / sec) was also plotted against calculated volume density. Standard regression analysis of these plotted data indicated a significant correlation (both R2 and adjusted R2 ≥ 80%). Thus, the process described above is capable of providing a proteinaceous (crunchy) food product that has a higher degree of firmness than similar products made by previously available methods. This characteristic potentially opens up the use of such food products in end-use applications where firmness is desired, for example, breakfast cereals and protein or nutrition bars.

Claims

1. A proteinaceous food product, characterized in that it has a volume density of 120 to 500 g / L, the food product comprising water, expanded starch and denatured proteins, at least 33 percent by weight of the proteins being ovalbumin.

2. The food product according to claim 1, characterized in that it comprises at least 35% (w / w) of expanded starch.

3. The food product according to claim 1, characterized in that most of the denatured proteins are derived from dried egg white.

4. The food product according to claim 3, characterized in that the dried egg white comprises egg white powder.

5. The food product according to claim 3, characterized in that the dried egg white is dried egg powder.

6. The food product according to any of claims 3 to 5, characterized in that the ratio of egg white powder to starch is 2:3 to 3:

2.

7. The food product according to claim 6, characterized in that the ratio is at least 1:

1.

8. The food product according to claim 1, characterized in that it comprises from 25 to 52.5 percent by weight of denatured proteins.

9. The food product according to claim 8, characterized in that it contains 30 to 72.5 percent by weight of carbohydrates.

10. The food product according to claim 1, characterized in that at least 35 percent by weight of the proteins are ovalbumin.

11. The food product according to claim 10, characterized in that at least 40 percent by weight of the proteins are ovalbumin.

12. The food product according to claim 11, characterized in that at least 45 percent by weight of the proteins are ovalbumin.

13. The food product according to claim 12, characterized in that at least 50 percent by weight of the proteins are ovalbumin.

14. The food product according to claim 1, characterized in that the volume density is at least 130 g / L.

15. The food product according to claim 14, characterized in that the volume density is at least 150 g / L.

16. The food product according to claim 15, characterized in that the volume density is at least 200 g / L.

17. The food product according to claim 16, characterized in that the volume density is at least 250 g / L.

18. The food product according to claim 17, characterized in that the volume density is at least 300 g / L.

19. The food product according to any of the preceding claims, characterized in that a portion size of 30 g comprises at least 10 g of protein.

20. A process for preparing a proteinaceous food product having a bulk density of 120 to 500 g / L, the method characterized in that it comprises: a) providing an extruder in which the temperature of each segment of the extruder barrel is maintained at no more than 30°C; b) introducing, on average, 10 to 20 L of water to each 100 kg of dry ingredients to provide an extrudable mixture, wherein dried egg white and starch comprise at least 95% of the dry ingredients and wherein the dried egg white and starch are present in a ratio of 2:3 to 3:2; c) conveying the extrudable mixture along the length of the extruder barrel, wherein the speed of the extruder screw is maintained at 200 to 600 rpm; d) allowing the extrudable mixture to exit the extruder barrel at a temperature of 100 to 165°C, in this way providing an extruded material having a moisture content of 10 to 25 percent by weight;(e) reduce the moisture content of the extruded material to less than 5 percent by weight, thereby providing the food product, 10 wherein at least 33 percent by weight of the proteins in the food product is ovalbumin.;