CA2183294A1 - Muscle extract coating on flexible packaging for color/flavor transfer - Google Patents

Abstract

A thermoplastic film is coated with a mixture of a muscle extract and a modifier, stuffed with meat, and heated. The coating transfers from the cook-in bag to the meat, imparting a desirable characteristic without interfering with the cooking process.

Description

2 1 83294 Field of the Invention This application relates to meat proces~ing More specifically, it relates to an hllplov~d method of h~lillg flavor, aroma and color to meat. A cook-in bag is coated with a solution of a meat extract and a modifier, stuffed with meat, and heated. The coating transfers from the cook-in bag to the meat, hn~lillg a desirable characteristic without illle~r~l;ng with the cooking process.

Back~round of the Invention In the processing of ham, beef, turkey and other meats, it is often desirable to add modifiers such as flavor, aroma or color additives to the surface of the meat as part of the cooking and pack~ging process. This is particularly true in the case of smoked meats, as traditional smoking processes add both color and flavor to the surface of the meat more intensely than the interior, however, it is true in other cases as well, such as the making of bothcooked and uncooked sausages and cheeses.
~oods are often packaged in a cook-in thermoplastic film bag or casing which is preferably shrinkable. A close fit is desirable, as it enhances productappearance by reducing wrinlcles, helps m~int~in product shape, and helps plc;vt;lll loss of liquid from the food. Similarly, it is usually desirable that the film has enough adhesion to the food to m~int~in the fit and reduce liquid loss during cooking, without being difficult to strip from the food when the package is opened after cooking.
Foods that are cooked in thermoplastic bags or casings may not brown.
As a consequence, in some food p~c1~ging processes the food is cooked, then the bag or casing is stripped from the food, the desired color is added, and thefood is then repackaged. A similar problem occurs if the food is smoked using

- 3 -liquid smoke. Traditional smoking entails exposure of a piece of meat to a cloud of smoke over an extended period of time. This process is time-co~ g and uneven in the result. Liquid smoke can be used to flavor the food more con~i~tently and in a shorter period of time, however, the food has to be cooked first, then stripped, dipped in or sprayed with the flavoring, and repackaged in order to obtain the proper flavor.
It would be convenient if thermoplastic films could be used to carry the desired additives to the surface of meats, as such films are easily processable.Further, if the additives are included with the film, then tlle film would not have to be stripped from the product after cooking. One-step cooking would be possible. Such a process would reduce material costs by using only one package, and would prolong shelf life by preventing cont~min~tion of the food during the stripping and rep~cl~ging steps. As a practical matter, the coating should separate cleanly from the film, and should not interfere with desirable surface characteristics of the film, such as adhesion (or lack of it).
There are many different recipes and modes of processing that are used by the food industry to prepare meats. Tastes and regional ~lerelences vary, so flexibility in the amount and type of additive would also be useful.
The present invention is directed to one of the more difficult coloring and flavoring problems, that of hl~lillg a pleasant color and smoke flavor to meats. The use of liquid smoke as an alternative to gaseous smoke is well known. United States Patent No. 3,330,669 issued to Hollenbeck July 11, 1967 discloses the use of liquid smoke thickened with a variety of materials and coated onto a container surface. This patent discloses that in theory, any thickener will do, and that a smoke solution thickened with guar gum could be applied to a polyamide film, dried, and used to flavor cheese. However, the e notes that this material is not suitable for coating on a high speed production line, See United States Patent No. 4,834,993,infra.. in part because

- 4 -the solutions tend to smear off the surface of the meat, See United States Patent No. 4,196,220, infra.
United States Patent No. 3,645,760 issued to O'Brien et al. Feb. 29, 1972 discloses dried sausage casings made by impregn~ting or coating a reinforcing paper, preferably a saturatable tissue, with a protein solution and treated with a non-toxic cros~linkin~ agent, which is disclosed to be liquid smoke, and drying.
United States Patent No. 3,427,169 issued to Rose et al. Feb. 11, 1969 relates to cellulosic casings for dried sausage treated with a soluble protein that is insolubilized by liquid smoke and which contains a mold inhibitor. A
drying step is required.
United States Patent No. 4,196,220 issued to Chiu, et al. April 1, 1980 relates to tubular food casings made of fibrous or non-fibrous regenerated cellulose treated with a mixture of albumin and modified liquid smoke.
Cellulose is not a thermoplastic, and is not used to make heat-shrinkable bags or c~ings Also, cellulose is easier to coat than thermoplastics. Further, each of the patents discussed above require a drying step to fix the coating onto the casing before the casing is filled.
United States Patent No. 4,196,220 issued to Chiu et al. April 1, 1980 relates to efforts to modify liquid smoke as an additive to a cellulosic or collagen casing for hot dogs and bologna. The patent discloses that unmodified liquid smoke is highly acidic and therefore incompatible with cellulosic materials at concentrations high enough to both flavor and color a food. The liquid smoke can be concentrated by adding propylene glycol, neutralizing, and boiling. Then the concentrate can be blended with egg white, propylene glycol and mineral oil. The coating mixture is applied to the casing, and dried. The egg white is disclosed to be essential to produce a smear-proof coating on the meat. However, there is no indication as to which egg-co~ p; formulations yield the preferred results, whether the coatings

- 5 2 1 83294 separate cleanly from the film, or which formulations, if any, are commercially useable.
United States Patent No. 4,834,993 issued to Chiu May 30, 1989 discloses that both the regular and the modified liquid smoke just discussed interferes with other additives that may be used on the interior of a casing. If, as in the case of hot dogs, peelability enhancing agents such as carboxymethyl cellulose are used in addition to the modified liquid smoke, the peelability agent will precipitate. Therefore, the liquid smoke may be applied to the outside of a cellulosic casing. In that instance, the liquid smoke is partially neutralized and tars which preci~ are filtered. This neutralized, filtered material produces a non-smear color, and avoids the fouling of equipment.
United States Patent No. 5,206,044 issued to Walton, Jr. April 27, 1993 relates to absorbent cellulosic paper impregnated with rosin and l~min~ted to alulnil,ulll foil or polyvinyl chloride film as a wrapper for a rosin-baked potato.
United States Patent No. 5,288,532 issued to Juhl, et al. Feb. 22, 1994 relates to an extruded film made from a water-swellable blend of a thermoplastic polymer such as ethylene vinyl acetate and an olefinic oxide polymer such as poly(ethylene oxide). This film is soaked with a liquid solution including a modifier such as liquid smoke, and used to make a cook-in pouch. The smoke color and flavor is said to be transferred in cooking from the film to the surface of any enclosed article. The results reported in the Examples show that unless the solution is dried onto the film before stllffing, color transfer is uneven. The question of color smearing after cooking was not addressed. The degree of color transfer is low, and the film retains a substantial amount of modifier when it is stripped from the food.

Advanta~es of the Invention It is an object of the present invention to provide an improved cook-in bag or casing for meat processing, one that can impart additional color, aroma,

- 6 -or flavor to meat during the cooking step. It is an advantage of this invention that the coated cook-in bag or casing as described herein not only has good color and flavor transfer but also retains an a~lop,iate amount of adhesion to the food product throughout the cooking process and upon subsequent storage, S thus minimi~ing product weight loss (purge).
It is yet another object of the present invention to provide an improved cook-in bag or casing that imparts desirable organoleptic characteristics to thefood, and yet can be used both on exi~ting food proces~ing equipment and with commercially available pack~ging m~t~ri~l~ It is an advantage of this invention that the coating described herein does not need a drying step between the coating and filling steps and so is more easily used with exi~ting p~C~ging equipment.

Summar,v of the Invention The advantages of the invention that are described just above can be obtained by use of a lni~ c of an aqueous meat or muscle extract with a modifier which is coated onto the interior surface of a cook-in bag or casing.
The coating can be used as is, and does not need to be dried. The bag or casing can then be stuffed, vacuum sealed or clipped, and heated. Upon h~ting, the coating will ll~lsrel with the modifier from the bag to the meat.
A preferred color modifier is caramel. A plcrelled flavor or aroma modifier is smoke. Spices, sugars and other flavorings can also be used.

Detailed D&~ ,lion of the Invention The Protein Extract The aqueous muscle extract of the present invention may be prepared by any conventional means. For example, a batter is prepared by blending or pulverizing the protein source in water. The batter preferably contains salt anda buffer. Ice may be added as a chopping aid and to m~int~in the low temperature of the ~ c. The liquid phase is then separated from the batter in any convenient manner, such as by centrifuging or filtration.
The source of the extract is most preferably a sample of the meat or other food product that is being packaged. The material is readily available, and will be compatible with both the ~xi~ting equipment and the food. It has been found that, particularly in the case of meats, different meats and different processes lead to di~r~le.ll results when coating is attempted. For that reason,non-muscle proteins such as gelatin and egg albumin have yielded inconsistent results when applied to a variety of different meat products.
The extract source is preferably defatted, as large amounts of fat tend to hl~elrelc with meat adhesion.

The Modifier The muscle extract is mixed with a modifier. The application is written in terms of the most plc~lcd modifiers, caramel and liquid or powdered smoke. However, one of oldhl~ skill in the art will readily recognize that other modifiers or blends of modifiers are useable.
By way of nonlimitin~ illustration, the modifier may be a colorant, flavorant, fragrance, spice, antioxidant, odor absorber, adhesion promoter, release agent or blends thereof.
Suitable colorants include food dyes such as FD&C colors or lakes.
Lakes are pigments formed by precipitation and absorption of a dye on a finely divided insoluble base. The most typical base in use is aluminum hydrate.
Such materials are commercially available from the Warner-Jenkins Co., St.
Louis, Mo.

Suitable fragrances are well known. These include vanillin, clove, citrus extracts. These often overlap with flavorants and spices such as pepper, garlic, and onion. However, a flavorant need not have a fragrance, as in the case of sugar.
Suitable anti-oxidants include those commonly used with foods, such as butylated hydroxy toluene, tocopherols and propyl gallate, as well as ascorbates. Odor absorbers include sodium citrate, epoxidized soybean oil and hydrotalcite. An example of an adhesion promoter is starch. A release agent might be carboxymethyl cellulose.

The Coating The modifier is added to the extract to make the coating. This composition can be readily coated onto the inside of commercially available cook-in bags by spraying, rolling, calen(l~ring or brushing. This can be done m~nll~lly or automatically on p~ ging equipment. Although the packager may choose to allow the coating to dry, the coating need not be dried before the bag or casing is stuffed.
The stuffed bags or casings are subjected to a cook-in step which is normal for that particular product, and cooled. Adhesion and purge control characteristics of the bag are substantially unchanged or even improved by the presence of the coating.

The Film The cook-in bags or casings described herein are made of a flexible thermoplastic film which preferably is heat-shrinkable or thermoformable. It is well known in the food p~cl~ging art to stuff thermoplastic bags or casings with various meat products, which may be solid chunks of meat (ham), an emulsion (hot dog), or in co~ luled form (breakfast sausage). Cook-in bags 2 t 83294 g can have a food contact surface made of a wide variety of thermoplastic materials, including polyolefins, homopolymers and copolymers of ethylene, propylene, butene, styrene, esters, acrylates and methacrylates ("(meth)acryl~tes"), urethanes, amides, polyamides and polyesters. Well-known classes of copolymers include the ethylene/~meth)acrylic acid or ester copolymers, including ionomers such as ethylene (meth)acrylic acid neutralized with sodium, zinc, or other ions, and ethylene/vinyl alcohol copolymer ("EVOH") including saponified or hydrolyzed ethylene/vinyl acetate copolymers. Other useful materials include those made by copolymerizing or grafting an olefin homopolymer or copolymer with an unsaturated carboxylic acid, such as maleic acid, fumaric acid or the like, and derivatives thereof such as anhydrides, esters or metal salts. These include, for example, maleic anhydride-grafted ethylene copolymers. These materials, and derivatives or blends thereof, are among those suitable for use with this invention.
As used herein, the phrase "cook-in" refers to the process of at least partially cooking a product packaged in a material capable of withst~n~1inp;
exposure to long and slow cooking conditions while co~ the food product, for example submersion in water at 57C to 121C (135F - 250F) for 1-12 hours, preferably 57C to 100C (135C - 212F) for 2-4 hours.
Cook-in pa~k~gin~ can be used to improve yield, give further assurance of food safety and sanitation, improve product flavor and appearance, and contribute to consumer convenience.
Cook-in Fask~ging materials must often m~int~in seal integrity. The films are usually heat-~hrink~ble under cook-in conditions so as to form a tightly fitting package. Further, the films may have marked adhesion (or release) properties, depending on the specific product being packaged. Some films preferably adhere to the food, thereby preventing the formation of purge, or pockets of moisture, between the food and the film. Other films, which are meant to be stripped from the food, must peel off very easily. Optional film characteristics which may be desirable are low gas permeability (gas barrier) and optical clarity.
The following experiments serve to illustrate the practice of the present invention, b~t do not limit its scope, or the scope of the claims which follow.

EXAMPLES
Example 1 Preparation of Chicken Extract Solution The chicken batter was prepared by mixing the components listed in Table 1. An extract was obtained by centrifuging this chicken batter. The 10yield of extract (the supern~t~nt portion) from the batter was approximately 50%. Other methods of making an extract from a chicken batter include filtration and squeegeeing.

Chicken Batter Formulation for Extraction of Protein Ingredient Weight (g) Defatted chicken 362 NaCl 43.1 Sodium Tripolyphosphate 7.15 Water 250 Ice 341 21 ~3294 Coating and Cook-in Test The extract obtained in the previous step was then mixed with a Caramel powder (Caramel 643 from D. D. Willi~m~on & Co., Inc., Louisville, KY) in a 2:1 ratio. The mixture was coated onto a piece of film having a food contact surface which is a blend of polyamides from a CN610 cook-in bag available from W. R. Grace & Conn., Duncan, S.C. to make a test film which was subjected to a cook-in test without any drying.

Chicken Batter Formulation for Cook-in Test Ingredient Weight (g) Defatted chicken 1500 NaCI 45 Sodium Tripolyphosphate 7.5 Water 227 Ice 302 For the screening cook-in test, a chicken batter was prepared according to the formulation shown in Table 2. The meat and half of the ice were chopped for 1 minute. Water, salt and phosphate were added in a brine form.
After the brine was absorbed, the rest of the ice was added. To~ chopping time was 6 minutes. The batter was stuffed into 4" inside diameter acrylic rings.
A coated test film was stretched over either side of the ring and secured by rubber bands. The rings were then cooked in a circulating water bath. The - 12- 2 1 832q4 cooking schedule was 30 minutes each at 60C, 65C, and 70C. After cooking, the samples were chilled in an ice slush for 90 ",i~ les The cover film which had a protein/caramel solution coating exposed to the meat was peeled off after cooking, and the color of the meat surface was observed to have an appetizing color on the surface. The peeled film was colorless, indicating subst~nti~lly complete color transfer. No purge was observed.
Comparative Example 1 The film used in this example was coated with Caramel. After cooking, there were small puddles of liquid (purge) which represents an undesirable loss of product weight.

Example 2 Same as in Example 1, except the chicken was replaced by pork. The same mixture as that in Table 1, with pork replacing chicken, was used for making the extract. The pork extract was mixed with Caramel powder at 2:1 ratio, and then coated onto films cut from CN610 bags.
For the testing batter in the cook-in test, a batter was prepared according to Table 2, except pork was used instead of chicken. An additional 0.015% sodium nitrite was used to simulate cured ham.
The cover film was peeled off after cook-in and an appetizing color on the surface was observed. The peeled film was clear, indicating subst~nti~lly complete color transfer. No purge was observed.

Example 3 Same as in Example 2, except that the cook-in bag has an ethylene-based ionomer inner layer (CN 510 cook-in-bag available from W. R. Grace &
Co.-Conn., Duncan, SC.).

The cover film was peeled off after cook-in and an appetizing color on the surface was observed. The peeled film was clear, indicating substantially complete color transfer. No purge was observed.

Example 4 Same as in Example 2, except that the cook-in bag had an inner surface made of an ethylene/propylene copolymer Co.~ g 97% propylene (CN 530 cook-in-bag from W. R Grace & Co.-Conn.).
The cover film was peeled off after cook-in and an appetizing color on the surface was observed. The peeled film was clear, indicating substantially complete color transfer. No purge was observed.

Claims (39)

What is Claimed is:

1. A flexible thermoplastic film with a food contact surface and a transferable coating on at least a portion of the surface, the coating comprising a muscle extract and one or more color, fragrance or flavor modifiers.

2. The film of Claim 1 wherein the food contact surface is selected from the group consisting of polyethylenes, polypropylenes, copolymers of ethylene and propylene, ethylene/(meth)acrylic acid copolymers and ionomers, polyamides, polyesters, ethylene vinyl acetates, ethylene vinyl alcohols, maleicanhydride-grafted ethylene copolymers, or blends thereof.

3. The film of Claim 1 wherein the food contact surface comprises a polyamide, an ethylene (meth)acrylic acid ionomer, an ethylene/propylene copolymer, or blends thereof.

4. The film of Claim 1 wherein the extract is selected from the group consisting of pork, beef, and poultry.

5. The film of Claim 1 wherein the modifier is selected from the group consisting of caramel and smoke flavor.

6. The film of Claim 1 wherein the coating further comprises a food-compatible salt.

7. The film of Claim 6, wherein the salt is sodium chloride.

8. The film of Claim 1 wherein the coating further comprises a food-compatible buffer.

9. The film of Claim 8, wherein the buffer is sodium tripolyphosphate.

10. The film of Claim 1, wherein the film is in the form of a cook-in bag.

11. The film of Claim 1, wherein the film is in the form of a cook-in casing.

12. The film of Claim 1 wherein the film is heat-shrinkable or thermoformable.

13. The film of Claim 1 further comprising a gas barrier layer.

14. A method of transferring color, aroma or flavor to meat, the steps comprising: packaging the meat in a flexible, thermoplastic film having a food contact surface on which is present a coating comprising a muscle extract and one or more modifiers, and subjecting the meat to a predetermined heating cycle whereby the meat is at least partially cooked and the modifier is transferred from the thermoplastic film to a surface of the meat so that when the bag is removed, the coating is substantially retained by the meat.

15. The method of Claim 14 wherein the food contact surface is selected from the group consisting of polyethylenes, polypropylenes, copolymers of ethylene and propylene, ethylene/(meth)acrylic acid or ester copolymers and ionomers, polyamides or polyesters, ethylene vinyl acetates, ethylene vinyl alcohols, maleic anhydride grafted ethylene copolymers, or blends thereof.

16. The method of Claim 14 wherein the food contact surface comprises a polyamide, an ethylene (meth)acrylic acid ionomer, an ethylene/propylene copolymer, or blends thereof.

17. The method of Claim 14 wherein the extract is selected from the group consisting of pork, beef, and poultry.

18. The method of Claim 14 wherein the modifier is selected from the group consisting of caramel and smoke flavor.

19. The method of Claim 14 wherein the coating further comprises a food-compatible salt.

20. The method of Claim 19, wherein the salt is sodium chloride.

21. The method of Claim 14, wherein the coating further comprises a food-compatible buffer.

22. The method of Claim 21, wherein the buffer is sodium tripolyphosphate .

23. The method of Claim 14, wherein the film is in the form of a cook-in bag.

24. The method of Claim 14, wherein the film is in the form of a casing.

25. The film of Claim 14 wherein the film is heat-shrinkable or thermoformable .

26. The film of Claim 14 further comprising a gas barrier layer.

27. A method of cooking meat wherein the meat is packaged in an enclosure comprising a thermoplastic film and subjected to a predetermined heating cycle whereby the meat is at least partially cooked, the improvement comprising providing a thermoplastic film having a contact surface on which is present a coating comprising a muscle extract and one or more modifiers whereby the modifier is substantially transferred to a surface of the meat, so that when the bag is removed, the modifier is substantially retained by the meat.

28. The method of Claim 27 wherein the food contact surface is selected from the group consisting of polyethylenes, polypropylenes, copolymers of ethylene and propylene, ethylene/(meth)acrylic acid or ester copolymers and ionomers, polyamides, polyesters, ethylene vinyl acetates, ethylene vinyl alcohols, maleic anhydride-grafted ethylene copolymers or blends thereof.

29. The method of Claim 27 wherein the food contact surface comprises a polyamide, an ethylene (meth)acrylic acid ionomer, an ethylene/propylene copolymer, or blends thereof.

30. The method of Claim 27 wherein the extract is selected from the group consisting of pork, beef, and poultry.

31. The method of Claim 27 wherein the modifier is selected from the group consisting of caramel and smoke flavor.

32. The method of Claim 27 wherein the coating further comprises a food-compatible salt.

33. The method of Claim 32, wherein the salt is sodium chloride.

34. The method of Claim 27 wherein the coating further comprises a food-compatible buffer.

35. The method of Claim 34, wherein the buffer is sodium tripolyphosphate.

36. The method of Claim 27, wherein the film is in the form of a cook-in bag.

37. The method of Claim 27, wherein the film is in the form of a cook-in casing.

38. The film of Claim 27 wherein the film is heat-shrinkable or thermoformable.

39. The film of Claim 27 further comprising a gas barrier layer.