Abstract:
A process for producing a food product containing omega-3 fatty acids is disclosed herein. The process includes the step of directing an edible coating for food through an apparatus operable to convert the coating from substantially solid form to substantially liquid form. The process also includes the step of combining at least one omega-3 fatty acid with the coating at least prior to completion of the directing step. The process also includes the step of maintaining the combined coating and at least one omega-3 fatty acid at a temperature of less than 120 degrees Fahrenheit during the directing step.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/822,408, filed on Aug. 15, 2006, which is hereby incorporated by reference in its entirety. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to an apparatus and method for producing food products with omega-3 fatty acids in a way that maintains the stability of the omega-3 polyunsaturated fatty aids over extended storage times. In particular, the invention is directed to maintaining stability of the omega-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). 
         [0004]    2. Description of the Related Art 
         [0005]    Long chain polyunsaturated fatty acids have been shown to be beneficial to human health. In particular, long chain polyunsaturated omega-3 fatty acids have been shown to be especially beneficial. The three that have been of primary interest include: linolenic acid (18:3w-3); eicosapentaenoic acid (EPA) (20:5w-3); and docosahexaenoic acid (DHA) (22:6w-3). The health benefits associated with enhanced consumption of these omega-3 fatty acids include a lowering of serum cholesterol, reduction of blood pressure, reduction in the risk of heart disease, and a reduction in the risk of stroke. These omega-3 fatty acids are also essential to normal neuronal development and their depletion has been associated with neurodegenerative diseases such as Alzheimer&#39;s disease. In the human eye and retina the ratio of DHA:EPA is 5:1 and their presence is necessary for normal eye development. The fatty acid DHA is also believed to be essential for optimal cognitive development in infants. Food fortified with DHA is often called “brain food” in Asian countries. Preliminary studies suggest that long chain polyunsaturated omega-3 fatty acids may play a role in mediating chronic inflammatory assaults and their use by individuals with mild asthma is documented to reduce the severity of the histamine response in asthmatics. 
         [0006]    There are several main sources of these beneficial long chain polyunsaturated omega-3 fatty acids. Certain plants provide an abundant source of linolenic fatty acid. Marine animals, such as fish and crustaceans, and marine plants, such as micro algae, are the main sources of EPA and DHA. In particular, fatty fish such as mackerel and salmon contain high levels of EPA and DHA. Marine micro algae contain predominantly DHA. Marine micro algae have an advantage as a source of DHA in that large volumes can be rapidly produced using modern methods and there is no need for the extensive acreage associated with fish farms or the difficulty of fishing. The omega-3 fatty acids are generally found in the form of triglycerides, i.e. one or more of the fatty acids connected to the glycerol backbone is an omega-3 fatty acid, and not in the form of free fatty acids. Both forms have the health benefits and associated oxidative instability. Therefore in this specification and the associated claims no distinction will be made between these two forms of omega-3 fatty acids. In this specification and the claims the term omega-3 fatty acid refers to both forms unless specifically noted otherwise. 
         [0007]    The beneficial effects of the omega-3 fatty acids, especially EPA and DHA, require relatively large amounts of the omega-3 fatty acids making it impractical to obtain the recommended daily amount merely by consuming fish. Thus, both have been made available in caplet form. Consumers do not generally enjoy consuming the caplets in part because they are large and also because the caplets can develop a fishy rancid type odor and taste rapidly. Prior attempts to add DHA and/or EPA directly to foods have been unsuccessful because they are very unstable and rapidly give rise to a fishy odor and taste upon oxidation, there by making the food unpalatable. It is believed that DHA and EPA are particularly unstable in the presence of water and heat, therefore their use in foods has been complicated and largely unsuccessful. Unlike other fatty acids these omega-3 fatty acids can not be stabilized in foods merely by adding well known antioxidants to the food. 
         [0008]    It is desirable to provide a simple process to allow for incorporation of oxidatively unstable fatty acids such as EPA, DHA and linolenic acid into foods that do not involve use of complex stabilizers and processing and that maintain the fatty acids in the unoxidized state. 
       SUMMARY OF THE INVENTION 
       [0009]    A process for producing a food product containing omega-3 fatty acids is disclosed herein. The process includes the step of directing an edible coating for food through an apparatus operable to convert the coating from substantially solid form to substantially liquid form. The process also includes the step of combining omega-3 fatty acids with the coating at least prior to completion of the directing step. The process also includes the step of maintaining the combined coating and omega-3 fatty acids at a temperature of less than 120 degrees Fahrenheit during the directing step. 
     
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of a first exemplary apparatus according to the invention; 
           [0011]      FIG. 2  is an exploded view of portions of the first exemplary apparatus; 
           [0012]      FIG. 3  is a perspective view of an application head of the first exemplary apparatus; 
           [0013]      FIG. 4  is a schematic view of an optional aspects of the first exemplary apparatus; 
           [0014]      FIG. 5  is a perspective view of a second exemplary embodiment of the invention; 
           [0015]      FIG. 6  is a schematic detail view of a longitudinal cross-section of a screw of the second exemplary embodiment; and 
           [0016]      FIG. 7  is schematic view of a third exemplary embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0017]    A plurality of different embodiments of the invention are shown in the Figures of the application. Similar features are shown in the various embodiments of the invention. Similar features have been numbered with a common reference numeral and have been differentiated by an alphabetic suffix. Also, to enhance consistency, features in any particular drawing share the same alphabetic suffix even if the feature is shown in less than all embodiments. Similar features are structured similarly, operate similarly, and/or have the same function unless otherwise indicated by the drawings or this specification. Furthermore, particular features of one embodiment can replace corresponding features in another embodiment unless otherwise indicated by the drawings or this specification. 
         [0018]    The invention relates to processes for producing food products with omega-3 fatty acids, apparatus&#39; for carrying out the processes, and the edible food products that result from practice of the processes and apparatus&#39;. Two embodiments of the invention are set forth below. Generally, each of the embodiments provide a process for incorporating omega-3 fatty acids that contemplates “gentle” handling of the omega-3 fatty acids to reduce the likelihood that the omega-3 fatty acids will oxidize. From one perspective, control over the temperature of the handling/manufacturing process is enhanced in the exemplary embodiments. For example, a maximum desirable temperature limit of 120° F. is established. From a second perspective, control over the mechanical stress experienced by the omega-3 fatty acids is enhanced. For example, gravity is used in part to move an omega-3 fatty acids containing coating to reduce the need to exert excess pressure on the coating to induce movement through the handling/manufacturing system. From a third perspective, control over exposure of the omega-3 fatty acids to oxygen is enhanced. For example, a flow or stream of inert gas can be directed at any point along the system to flush oxygen away from the omega-3 fatty acids, the coating, or the combined omega-3 fatty acids and coating. Individually and cumulatively, these perspectives increase the shelf-life of the coating, whether the coating is applied directly onto another food product such as a bar, or whether the coating is mixed as discrete pieces with other discrete food pieces such as ready-to-eat (RTE) cereal. The invention provides the benefit of increasing the shelf-life of the omega-3 fatty acids containing coating, the shelf-life defined by the time period lasting until the coating exhibits an appreciable fishy odor or taste. 
         [0019]    As discussed above marine animals and marine plants are the main sources of EPA and DHA omega-3 fatty acids. The use of fish oils as a source of EPA and DHA is well known. Recently, a number of manufactures have developed processes for growing marine micro algae with high efficiency. These micro algae are a great source of EPA and DHA at very high yields in a completely renewable process. Such micro algae derived EPA and DHA are available from a number of sources. One source of micro algae derived EPA and DHA is Martek Biosciences Corporation, Columbia, Md., USA. A second source of micro algae derived EPA and DHA is Nutrinova Nutrition Specialties and Food Ingredients, DE. The omega-3 fatty acids can be provided as a free flowing powder for the present invention or as a liquid oil, usually including an additional carrier oil. To make the powdered form, typically, the fatty acids are plated onto bulking agents such as corn syrup solids, mannitol, calcium carbonate, whey protein isolate, gluten, pregelatinized starches, cellulose fiber, carbohydrates, gelatin, flour, grain, bran, freeze dried whole fruits and fruit powders. The plated powders are then spray dried to form a free flowing powder. The omega-3 fatty acids can be provided as the free fatty acid or in the form of triglycerides, generally the triglyceride form is more stable. In the present specification and claims unless specifically noted there will be no distinction made between the free form or the triglyceride form of the omega-3 fatty acids or whether the omega-3 fatty acids are used as a powdered form or in the form of a liquid oil. 
         [0020]    Referring now to  FIGS. 1-4 , in a first exemplary embodiment of the invention, omega-3 fatty acid is moved through an apparatus  10  and applied to a food product  12 . The food product in the first exemplary embodiment of the invention is a snack bar  12 . In alternative embodiments of the invention, the food product could be, for example, ready-to-eat (RTE) cereal, toaster pastries, crackers, and/or fruit pieces. 
         [0021]    The omega-3 fatty acid is an ingredient of a coating applied to the food product, a coating such as chocolate or a compound coating. Chocolate and compound coating are not necessarily mutually exclusive; a compound coating can include cocoa powder and be chocolate flavored. Generally, a compound coating is a confectionary product based on vegetable fat. For example, the fat can be provided to the compound coating by cocoa butter, palm kernel oil, coconut oil, partially hydrogenated forms of palm kernel oil or coconut oil or soybean oil as some examples. In addition to vegetable fat the confectionary or compound coatings typically contain sugar and may optionally contain flavorings such as cocoa solids, peanut solids, other natural or artificial flavors, emulsifiers, coloring agents, salt, and milk solids. 
         [0022]    In the first exemplary embodiment of the invention, a compound coating  14  in the form of solid discrete pieces is liquefied and applied to the snack bar  12 . The apparatus  10  is operable to convert the coating  14  in substantially solid form to substantially liquid form for application to a food product or for creation of a discrete piece of omega-3 fatty acid containing coating. 
         [0023]    The omega-3 fatty acid is pre-mixed with the other ingredients of the compound coating  14  in the first exemplary embodiment of the invention. However, in alternative embodiments of the invention, the omega-3 fatty acid can be combined with the coating by the apparatus carrying out a process according to the invention, as shown in the second exemplary embodiment of the invention set forth below. In the invention, the omega-3 fatty acid is mixed with the coating at some point prior to the dispensing of the coating from the apparatus. 
         [0024]    The first exemplary apparatus  10  includes an auger assembly  16  to convert the coating  14  from substantially solid form to substantially liquid form. In alternative embodiments of the invention, an apparatus for practicing the invention may include structures other than an auger/screw design. Separate components, one for melting/liquefying the coating and one for mixing the omega-3 fatty acid, can be cooperatively engaged to practice the invention. An advantage of a screw/auger arrangement is that the process can be a “first-in, first-out” process whereby the compound coating need not be maintained in liquid form in a vat for extended periods of time. In other words, the apparatus of the first exemplary embodiment of the invention is non-recirculating. However, if this not deemed an advantage in certain operating environments, the invention can be practiced in other ways to achieve different advantages. An apparatus for practicing the invention “starts” when the temperature of the coating is 120° F. or less. 
         [0025]    The apparatus  10  also includes a distribution manifold  18 , a plurality of metering pumps  20 , and a plurality of application heads  22 . The auger assembly  16  includes a hopper  24  for receiving a mass of the compound coating  14 , a tube-like auger housing  26 , a screw or auger  28 , a drive motor  30 , and heating bands  32 ,  34 . The hopper  24  communicates the mass of compound coating  14  to auger housing  26 . The auger  28  is disposed in the auger housing  26  for rotation. The motor  30  drives the auger  28  in rotation. In operation, the rotation of the auger  28  draws the compound coating from the hopper  24 , through the auger housing  26 , and toward the manifold  18 . 
         [0026]    As best shown in  FIG. 4 , the exemplary hopper  24  is constructed with a hollow wall such that a stream of coolant such as water can be directed through the hopper  24 , around the compound coating  14  disposed in the hopper  24 . The stream of coolant can be any desired temperature to reduce the likelihood of oxidation of the omega-3 fatty acid in the compound coating  14 . In the first exemplary embodiment of the invention, the stream of coolant is substantially maintained at a temperature of 50° F. 
         [0027]    It can be desirable to heat the compound coating slightly to promote passage of the compound coating through the auger assembly  16 . Heating changes the compound coating  14  to a molten state and reduces the viscosity of the compound coating  14  and enhances the flow of the compound coating  14 . The heating bands  32 ,  34  are arranged downstream of the hopper  24  along the auger housing  26  to gradually heat the compound coating  14  to about 105° F. Heating of the compound coating  14  occurs in the enclosed auger housing  26  portion of the auger assembly  16  and not the open hopper  24 . 
         [0028]    Maintenance of a desired temperature at any position along the auger assembly  16  can be controlled or enhanced by application of a water bath at the desired temperature. 
         [0029]    The compound coating  14  moves from the auger assembly  16  to the distribution manifold  18 . Although not shown in the drawings, the manifold  18  can be heated as desired to raise the temperature of the compound coating  14 . Alternatively, the temperature of the compound coating  14  can be maintained between 100° F. and 110° F. throughout the apparatus  10  from the auger housing  26  to the application heads  24 . 
         [0030]    The compound coating  14  moves through the distribution manifold  18  to the plurality of metering pumps  20 . The pumps  20  enhance the precision of and control over the flow of compound coating  14  through the application heads  22 . The compound coating  14  is dispensed onto the snack bars  12  from the application heads  22 . The dispensing heads  22  dispenses the compound coating  14  in the form of line, but alternative embodiments of the invention can include dispensing heads that dispense the omega-3 fatty acid mixture in spray form. In still other embodiments, the omega-3 fatty acid mixture may be dispensed separately from the food item and added 
         [0031]    As best shown in  FIG. 4 , the exemplary apparatus  10  also includes a system  36  for delivering inert gas to various locations to further reducing the likelihood that the omega-3 fatty acid will be exposed to oxygen and oxidize. For example, inert gas at greater than atmospheric pressure can be directed to the hopper  24 . Inert gas can also be directed to the application heads  22  to enhance the flow of the compound coating  14  out of the heads  22 . 
         [0032]    Referring now to  FIGS. 5 and 6 , a second exemplary apparatus  10   a  includes an auger assembly  16   a,  a metering pump  20   a,  and an application heads  22   a.  The auger assembly  16   a  includes a hopper  24   a  for receiving a mass chocolate, an auger housing  26   a,  an auger  28   a  (shown in  FIG. 6 ), a drive motor  30   a,  and heating bands  32   a,    34   a.  The hopper  24   a  communicates the mass of chocolate to the auger housing  26   a.  The auger  28   a  is disposed in the auger housing  26   a  for rotation. The motor  30   a  drives the auger  28   a  in rotation. In operation, the rotation of the auger  28   a  draws the chocolate from the hopper  24   a,  through the auger housing  26   a,  and toward the metering pump  20   a.    
         [0033]    The apparatus  10   a  includes a cooling band  38   a  proximate to the hopper  24   a.  The cooling band  38   a  can be sleeve-like, surrounding the auger housing  26   a,  and channeling a flow of cooling fluid such as water around the auger housing  26   a.  The auger assembly  16   a  can be cooled at the location of the hopper  24   a  to reduce the likelihood that the temperature of the hopper  24   a  will increase and thereby induce melting of the chocolate prior to entry into the auger housing  26   a.  In the second exemplary embodiment of the invention, the stream of coolant can be substantially maintained at a temperature of 50° F. 
         [0034]    It can be desirable to heat the chocolate slightly to promote passage of the compound coating through the auger assembly  16   a.  Heating changes the chocolate to a molten state and reduces the viscosity of the chocolate, thereby enhancing the flow of the chocolate. The heating bands  32   a,    34   a  are arranged downstream of the hopper  24   a  along the auger housing  26   a  to gradually heat the chocolate to about 105° F.-110° F. Heating of the chocolate occurs in the enclosed auger housing  26  portion of the auger assembly  16   a  and not the open hopper  24   a.  The heating bands  32   a,    34   a,  can be sleeve-like, encircling the auger housing  26   a  and channeling a flow of heating fluid such as water. The bands  32   a,    34   a,    38   a  are fed coolant by the pumps and fluid lines shown in  FIG. 5 . 
         [0035]    The heating band  32   a  is disposed substantially immediately upstream of a second hopper  40   a.  The second hopper  40   a  communicates with the interior of the auger housing  26   a  and is operable to receive omega-3 fatty acid in powder form. The omega-3 fatty acid in powder form is encapsulated. Martek Biosciences Corporation of Maryland produces an encapsulated form of omega-3 fatty acid that can be used in embodiments of the invention, such as the product number KSF35D. In alternative embodiments of the invention, omega-3 fatty acid in forms other than powder may be introduced to the interior of the auger housing  26   a  through the hopper  40   a.    
         [0036]    In the second exemplary of the invention, the hopper  40   a  is disposed at a location along the auger housing  26   a  where the chocolate is not fully melted. The omega-3 fatty acid therefore initially contacts the chocolate at a relatively lower temperature. The combined omega-3 fatty acid and chocolate is further heated by the heat band  34   a  downstream. Thus, the chocolate is heated in a first stage to first temperature by the band  32   a  and is heated in a second stage to a second temperature by the band  34   a.  The first temperature can be between about 100° F.-105° F. and the second temperature can be between about 110° F.-120° F. As a result of the arrangement of the second exemplary apparatus  10   a,  the temperature of the omega-3 fatty acid rises gently, with the rise in temperature of the chocolate. 
         [0037]    The amount of omega-3 fatty acid added through the hopper  40   a  can be any amount desired. For example, the amount of omega-3 fatty acid introduced to the auger interior can result in a mixture of omega-3 fatty acid and chocolate that is dispensed on the food product having a ratio of between about 1 milligram of omega-3 fatty acid per gram of chocolate to about 100 milligrams of omega-3 fatty acid per gram of chocolate. 
         [0038]    The heating band  34   a  is disposed substantially immediately downstream of a second hopper  40   a.  The heating band  34   a  gently raised the temperature of the combined omega-3 fatty acid and chocolate to a temperature desirable for dispensing the mixture on a food product and below 120° F. The mixture of omega-3 fatty acid and chocolate exits the auger assembly  16   a  and is received in a reservoir  42   a  associated with the metering pump  20   a.    
         [0039]    Alternative embodiments of the invention can incorporate more cooling and/or heating bands.  FIG. 7  schematically shows a variation in which the chocolate or compound coating is heated and then cooled prior to receiving the omega-3 fatty acid. An apparatus  10   b  includes a motor  30   b  and an auger assembly  16   b  with an auger housing  26   b.  Heating bands  32   b  and  34   b,  cooling bands  38   b  and  44   b,  and hoppers  24   b  and  40   b  are disposed along the auger housing  26   b.  This variation may be desirable when chocolate is used to combine with omega-3 fatty acid. For example, to prevent blooming of the chocolate, it may be desirable to heat the chocolate greater than 120° F. with the heating band  32   b.  The cooling band  44   b  can cool the chocolate prior to combination with the omega-3 fatty acid through the hopper  40   b.    
         [0040]    Referring again to  FIG. 6 , the screw  28   a  rotates about a centerline  46   a.  The coating moves along the centerline  46   a  in the direction of arrow  48   a.  The configuration of the thread of the screw  28   a  changes along the centerline  46   a.  Portions  50   a,    52   a  of the thread are disposed upstream of portions  54   a,    56   a.  The height of the portions  50   a,    52   a  is greater than the height of the portions  54   a,    56   a.  The distance between the portions  54   a,    56   a  is greater than the distance between the portions  50   a,    52   a.  The operational effect of these differences is that substantially the same quantity of coating (as measured by the cross-section for convenience) can be disposed between portions  50   a,    52   a  as is disposed between portions  54   a,    56   a.  However, the quantity of coating disposed between portions  54   a,    56   a  is less deep and contacts the housing  26   a  over a greater area than the quantity of coating disposed between portions  50   a,    52   a.  Thus, control over the temperature of the quantity of coating disposed between portions  54   a,    56   a  is enhanced. 
         [0041]    The apparatus  10   a  can be arranged such that the combined coating (chocolate in the second exemplary embodiment of the invention) and omega-3 fatty acid travel together only through the narrowed section of the screw assembly  16   a  at which the thread of the screw  28   a  is relative short and widely spaced. In other words, it may be desirable to combine the omega-3 fatty acid with the chocolate to the housing  26   a  at the point immediately prior to the screw thread becoming short and widely spaced. Alternatively, it may desirable to combine the omega-3 fatty acid with the chocolate to the housing  26   a  at a point subsequent to the screw thread becoming short and widely spaced so that the temperature of the chocolate is more precisely controlled prior to combining with the omega-3 fatty acid. 
         [0042]    Referring to  FIG. 5 , the auger assembly  16   a  is oriented at a downward angle, the entry point being gravitationally higher than the exit point. This arrangement brings the advantage of reducing mechanical stress on the omega-3 fatty acid. Specifically, gravity is used to reduce and/or eliminate the need to build up positive pressure in the auger housing  16   a  to move the combined coating and omega-3 fatty acid. 
         [0043]    The combined coating produced by the first and second embodiments of the invention is substantially homogenous. The omega-3 fatty acid is generally evenly dispersed in the compound coating. As a result, the output of the system will include some quantity of omega-3 fatty acid at a surface. The output of the system can be a layer disposed on top of, below, or around another edible item. Such a layer will have some quantity of omega-3 fatty acid exposed, not covered by the coating or the other food item. The output of the system could also be a discrete piece, to be added to some other edible product or to be consumed as-is. Such an output will have some quantity of omega-3 fatty acid exposed. 
         [0044]    The combined coating and omega-3 fatty acid can be applied to a food bar. In one embodiment, a quantity of the combined coating was applied to a food bar having a water activity of about 0.6. The bar has been subjected to an accelerated shelf life test, at 85° F. It has been observed that, currently, the coated bar has not exhibited a fishy aroma and taste after 20 weeks storage. It is believed that the coated bar may not exhibit a fishy aroma and taste after 36 weeks storage. 
         [0045]    The present invention is directed to processes, apparatus, and food products with omega-3 fatty acid. However, the teachings herein can be applied to applying any nutriceutical sensitive to temperature, mechanical stress, and chemical reaction (oxidation or other chemical reactions analogous to oxidation) to a food product. Probiotics, anti-oxidants, and other sensitive nutriceuticals can be incorporated into a food product by the teachings set forth herein. 
         [0046]    The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and do come within the scope of the invention. Accordingly, the scope of legal protection afforded this invention can only be determined by studying the following claims.