WO2007006035A1

WO2007006035A1 - Products and methods for processing of marine animals

Info

Publication number: WO2007006035A1
Application number: PCT/US2006/026467
Authority: WO
Inventors: Jeffrey G. Knauf
Original assignee: Alaska Ocean Products Corporation
Priority date: 2005-07-05
Filing date: 2006-07-05
Publication date: 2007-01-11

Abstract

A method is provided for the processing of edible marine animals. Animals are frozen whole in a pre-rigor mortise state with no bruising, no flesh gaping, and no rancidity or oxidation. The method includes partially thawing the animal for a time effective for providing a gut surface temperature of at least about 32 .F., opening a body cavity of the animal, and removing entrails of the animals .

Description

PRODUCTS AND METHODS FOR PROCESSING OF MARINE ANIMALS

The present invention relates to methods for processing marine-animals and methods and product produced from marine animals. More particularly, a partial thaw method is provided that allows for efficient removal of entrails and which is effective for providing a high quality stable starting material that can be utilized to produce superior quality products with subsequent processing.

BACKGROUND

The usual industrial practice of catching fish or harvesting sea-food produce is to bring them on board of the fishing boat where processing of the catch occurs. Most of the time, fishing boats remain at sea for 5 days or more. Therefore, it becomes necessary to process the catch as soon as possible and prevent it from turning bad. This is especially true for the catch obtaining during the early days at sea. A common practice is to store the catch in a refrigerated space mixed with an equivalent amount of crushed ice. When brought back to the port, the catch is either sold as fresh or more likely processed in various ways such as canning, smoking or freezing.

As soon as the catch is taken out of its living environment (sea water), degradation processes start. Chemical and bacteriological reactions are the major sources of fresh fish and sea-food degradations.

Bacterial contamination has many origins . Part of it comes from ambient air, but handling, cleaning and storing operations are the major responsible factors for contamination of the product. When living in its natural environment, edible parts of fish or sea-food have an extremely low level of contamination (e.g., below 10 germs/g) . However, it is not unusual to observe that level rising to 10⁴ or more germs/g after the product has been through every processing step. The higher the initial level of contamination, the faster the deterioration of the product will be and ultimately, part of the caught .stock has to be destroyed because of its total loss of market value.

Refrigerated fish which is brought back to port is processed to remove entrails by using conventional processes. These processes tend to be very messy and add to contamination and cross-contamination problems.

Contamination problems directly impact the quality of any products subsequently produced.

When processing the salmon roe into food, generally, the whole of the ovary of a salmon (including a trout) , which incorporates numerous salmon eggs (ova) sticky with one another, is taken out by incising the abdomen of the salmon so as to damage salmon ova as little as possible without peeling the ovarian membrane embracing the salmon ova. The salmon roe is thus processed for the reason that the salmon ovary having the ova embraced with the outer ^■ membrane appears to be gorgeous and can be sold at high prices. The salmon roe (spawn) taken out of the ovary is immersed in saturated salt water for 15 to 40 minutes, and thereafter, stirred softly. Then, the roe is drained, packed into a packing case and kept in a room at 5 "C. to 15 "C. for 3 to 6 days as it is so as to have moderate salinity. Thus, the salted salmon roe is obtained and placed on the market so as to be served as ingredients for sandwiches and topping for a canape. Omega-3 highly unsaturated fatty acids are of significant commercial interest in that they have been recently recognized as important dietary compounds for preventing arteriosclerosis and coronary heart disease, for alleviating inflammatory conditions and for retarding the growth of tumor cells. These beneficial effects are a ^• result both of omega-3 highly unsaturated fatty acids causing competitive inhibition of compounds produced from omega-6 fatty acids, and from beneficial compounds produced directly from the omega-3 highly unsaturated fatty acids themselves (Simopoulos et al., 1986). Omega-6 fatty acids are the predominant highly unsaturated fatty acids found in plants and animals. Currently the only commercially available dietary source of omega-3 highly unsaturated fatty acids is from certain fish oils which can contain up to 20-30% of these fatty acids. The beneficial effects of these fatty acids can be obtained by eating fish several times a week or by daily intake of concentrated fish oil. Consequently large quantities of fish oil are processed and encapsulated each year for sale as a dietary supplement.

The quality of any products produced from marine animals or fish is directly related to the quality of the starting material. The quality of subsequent products such as fillets, roe, protein hydrolysates, and omega-3 fatty acids has been limited due to the inconsistent and poor quality of the starting raw material.

SUMMARY A method is provided for the processing of edible marine animals . Animals are frozen whole in a pre-rigor mortise state with no bruising, no flesh gaping, and no rancidity or oxidation. Importantly, the present method maintains the mucosal layer of the animal and keeps cell and membrane structures intact by minimizing ice crystal formation and evaporative effects. Animals processed according to the method have a natural shape, a natural flesh color and no frozen dents from plates, -blast trays or pans. The method provides for easier subsequent processing of the animals as at least about 50% of the animals blood is removed before freezing. Animals processed in accordance with the invention may be maintained in a frozen state for up to four years without any noticeable difference from freshly- processed animals. The partial thaw method described herein allows for efficient removal of entrails and which is effective for providing a high quality stable and consistent starting material that can be utilized to produce superior quality products with subsequent processing.

The method provides for the processing ^"of marine animals, especially fish. The method includes a partial thaw process that is effective for allowing removal of entrails as one continuous unit. Since blood is substantially removed prior to cleaning, the cleaning operation is much cleaner and minimizes contamination of the product and any subsequent products . The method is effective for preserving and enhancing the quality of the marine animal itself and for preserving and enhanceing the quality of other products which may produced from the marine animal. For example, entrails which are removed from the animal may be re-frozen and/or further processed for roe and omega-3 fatty acids. The method is further effective for preserving and enhancing the mucosal layer of the marine animal such that the mucosal layer can be utilized as a healing composition. In one aspect, a method is provided for processing frozen edible marine animals that includes partially thawing the animal for a time effective for providing a gut surface temperature of at least about 32 'F, preferably about 33 "F to about 46 'F. These temperatures result in the gut area being slightly more flexible to the touch. Subsequently, the body cavity of the animal is opened and the entrails of the animal are removed as a single continuous unit. Subsequently, the blood line of the animal may also be removed. In another aspect, a method is provided for processing edible marine animals that includes stunning, exsanguinating and freezing of the animal. The animal is first stunned an aqueous medium. After stunning, the animals are exsanguinated. After exsanguinating, the animals are frozen by contacting the animals with a liquid cooling medium having a temperature of below 32 'F. The animals are maintained in the cooling medium for a time period effective for providing a core temperature of at least about 25 'F or lower in the animal. Further processing of the animals may be accomplished by partially thawing the animal for a time effective for providing a gut surface temperature of at least about 32 'F, preferably about 33 'F to about 46 'F. Subsequently, the body^" cavity of the animal is opened and the entrails of the animal are removed as a single continuous unit. Subsequently, the blood line of the animal may also be removed. In another aspect, a method is provided for recovering roe. Fish are stunned, exsanguinated and frozen as described herein. Further processing of the fish may be accomplished by partially thawing the fish for a time effective for providing a gut surface temperature of at least about 32 'F, preferably about 33 "F to about 46 'F. Subsequently, the body cavity of the fish is opened and the entrails of the fish are removed. The roe is then removed from the remaining entrails. The roe may be frozen or thawed in a brine solution. In another aspect, a method is provided for producing a proteinaceous product. In accordance with the method, marine animals are stunned, exsanguinated and frozen as described herein. Further processing of the animal may be accomplished by partially thawing the animal for a time effective for providing a gut surface temperature of at least about 32 'F, preferably about 33 'F to about 46 "F. The whole animal or animal parts are processed into a ground condition and the ground materials are hydrolyzed. Partially hydrolyzed proteins ^" and amino acids may then be recovered from the hydrolysate.

In another aspect, a method is provided for producing omega-3 fatty acids . In accordance with the method, marine animals are stunned, exsanguinated, frozen, and partially thawed as described herein.^' Omega-3 fatty acids may then be extracted from the animal . In an important aspect, at least a portion of the liver may be removed from the animal and omega-3 fatty acids may be extracted from the liver.

In another aspect, a method is provided for producing a healing composition. In accordance with the method, marine animals are stunned, exsanguinated, frozen, and partially thawed as described herein. A mucosal layer is removed and utilized as a healing composition.

DETAILED DESCRIPTION In accordance with the method as claimed, edible marine animals are stunned, exasanguinated and then freezing, in a liquid cooling medium without removal of the entrails of the animal. As used herein, "edible marine animals" refers to any marine animals that have a mucosal or slime layer. More particularly, edible marine animals refers to fish. Some examples of fish that may be processed include salmon, trout, pollack, flounder, halibut, whitefish, and sole.

Stunning Stunning of the marine animals may be accomplished by any suitable methodology that does not substantially disrupt the mucosal layer of the animal. Examples of suitable stunning methods include electrical shocking of the fish and the use of a stunning gas. Stunning gases that may be used include carbon -dioxide and any of the inert gases, such as nitrogen.

Stunning of marine animals using stunning gas may be accomplished by placing the animals into holding containers which have been sparged with a stunning gas . Sparging of water in the holding tanks is effective for reducing the oxygen levels in the water such that animal placed into the holding tank becomes unconscious or nearly unconscious. Animals which have become unconscious or nearly unconscious do not thrash around and hence are less likely to damage and/or disrupt their mucosal layer. Exsanguinating

Animals which have been stunned are exsanguinated by any suitable methodology. In an important aspect the animals, such as a fish a kept under water and one of the fish's gills is cut. The fish's heart continues to pump until the fish has lost a substantial amount of blood, preferably at least about 50%, more preferably at least about 75%, and most preferably at least about 90%. The removal of blood makes subsequent removal of entrails much easier and neater. Further, removal of blood contributes to the enhanced quality products produced from the animal .

Freezing After stunning and exsanguintating, animals are placed into cooling medium that is maintained at a temperature of 32 'F or lower, more preferably 25 ^*F or lower, more preferably 20 'F or lower, more preferably 15 "F or lower, more preferably 10 "F or lower, more preferably 0"F or lower, more preferably -5 'F or lower, more preferably -10 'F or lower, more preferably -15 "F or lower, more preferably -20 "F or lower, more preferably -25 'F or lower, more preferably -30 'F or lower, more preferably -35 "F or lower, and more preferably -40 'F or lower. Fish are frozen for a time sufficient to reach a core temperature of 25 'F or tower, more preferably 20 'F or lower, more preferably 15 'F or lower, more preferably 10'F or lower, more preferably 5 'F or lower, more preferably O'F or lower, more preferably more preferably O'F or lower, -10'F or lower, more preferably -15 'F or lower, and more preferably -20 'F or lower,

Time periods for freezing are effective for preventing ice crystal formation that could rupture cellular structures. In this aspect, the time required to reach a desired core temperature will be about 3 hours or less, more preferably 2.5 hours or less, more preferably 2 hours or less, more preferably 1.5 hours or less, more preferably 1.0 hours or less, more preferably 0.5 hours or less, and more preferably 40 minutes or less. The frozen animal is then placed into cold storage at any temperature of about 20 'F or less. The cooling medium used in the present method includes an organic cooling agent, preferably in combination with a chloride salt. The chloride salt is preferably at least one selected from the group consisting of sodium chloride, magnesium chloride and calcium chloride. For economic reasons, the chloride salt is preferably sodium chloride. Calcium chloride is believed to provide solutions that yield the lowest freezing point and is thus more generally preferred. The organic cooling agent may be any suitable organic cooling agent. Preferred cooling agents include carbohydrates having a molecular weight ranging from 180- 1500, sugar alcohols having a molecular weight ranging from 180-1500, glycosides having a molecular weight ranging from 180-1500, maltodextrins , hydrogenated maltodextrins, starch hydrolyzates, hydrogenated starch hydrolyzates, and non-toxic oils, -and any mixture of the foregoing and of other organic cooling agents. Generally, when an oil is used, it is not used in conjunction with a chloride salt or aqueous medium. Examples of oils that ^"may be used include vegetable oils, citrus oils, crucifer oils, and mixtures thereof

At least some of the foregoing organic cooling^" agents are believed to provide beneficial effects when used in conjunction with the freezing of edible marine animals and other food products, in that preservation of the mucosal layer is believed to be enhanced, although the invention should not be deemed limited to any such enhanced effect In addition, certain of the foregoing cooling agents are believed to contribute to a lowering of freezing point in addition to the colligative lowering contributed by the presence of the dissolved material in solution. If a carbohydrate^" is used, the carbohydrate may be any suitable carbohydrate, and may include, for instance, glucose, maltose, maltotriose, lactose, fructose, sucrose, and mixtures thereof. The sugar may be selected from monosaccharides, disaccharides, trisaccharides, tetrasaccharides, pentasaccharides, hexasaccharides, and mixtures thereof. Sugar alcohols of the foregoing, such as sorbitol and maltitol, or other sugar alcohols in the weight range provided may be used in conjunction with the ' invention. The carbohydrate may be provided as a pure solution, but ordinarily is provided in admixture with other materials, in that an industrial waste stream that includes carbohydrates may be used as a source of such carbohydrates . Carbohydrates can be obtained from a wide range of agricultural based products such as those derived from corn, wheat, barley, oats, sugar cane, sugar beets etc. Suitable sugars include, but are not limited to, corn sugar, cane sugar, beet sugar, sorghum sugar, maple sugar, wheat sugar, tapioca sugar, potato sugar, cassava sugar, and manioca sugar.

In one alternative aspect, animals being processed - may be stunned and exsanguinated on deck and then placed directly into a fish hold. In this aspect, the fish hold may include the cooling medium.

Processing of Marine Animals

The present method allows for easy removal of all entrails of the animal. As used herein "entails" refers to all internal parts of the animal . Entrails may include for example, the gut, roe, liver, heart and other internal organs of the animal. In accordance with the method, the animal is partially thawed to a temperature of at least about 32 'F, preferably about 33 "F. Upon opening of the body cavity, the entrails can be removed as a single unit. As used herein, a "single unit" refers to a continuous piece of entrails that remain together upon removal from the animal. The single unit includes substantially all of the entrails of the animal. The method allows for very clean processing as substantially all of the blood of the animal was previously removed. After removal of the entrails, the blood line of the animal is then also easily removed. Subsequently, further processing may be done to remove the head, tail and skin of the animal .

Processing of Roe

Roe particles enveloped in the ovary membrane are typically salmon roes, in which a number of eggs of, e.g., salmon and trout, are enveloped in the ovary membrane. However, it is to be noted that a number of any roe particles enveloped in the ovary membrane are within the scope of the present invention.

Upon removal of the entrials, the roe may be easily removed as a single unit. The roe may then be maintained and further stored as frozen or be thawed in a brine solution. The brine solution may include known additives commonly used in curing of roes . Roe which recovered in accordance with the process has the same quality as fresh roe that was never frozen, even after being maintained in a frozen state for up to 4 years.

Proteinaceous Products

In another aspect, a method is provided for producing proteinaceous products, such as for example protein supplements for human and animal foods. The whole animal, such as the whole fish, or any parts of the animal may be utilized. Any known hydrolysis procedures may be used to produce the proteinaceous products . Examples of hydrolysis procedures that may be used are described in U.S. Patent No. 5,053,234, 5,113,755 and 5,162,129, all which are incorporated herein by reference. The proteinaceous products produced from animals processed in accordance with the method described herein have superior quality over proteinaceous products process from animals frozen by conventional freezing methods . Omeσa-3 Fatty Acids

In another aspect, a method is provided for producing omega-3 fatty acids. In this aspect, the whole animal may be utilized or portions of the animal which are know to be rich in omega-3 fatty acids may be utilized, such as for example fish liver. Omega-3 fatty acids may be extracted and produced by methods known in the art. Omega-3 fatty acids produced from animals processed in accordance with the methods described herein have superior quality over omega-3 fatty acids produced from animals frozen by conventional freezing methods.

Healing Compositions

In another aspect, a method is provided for producing healing compositions. Marine animals which have been frozen in accordance by the methods described herein may be partially thawed and then further processed to remove the mucosal layer. The mucosal layer may include the slime layer, scales, peptides, antibodies, mast cells, piscidins, and mixtures thereof. The mucosal layer may be removed using drip catchments, vacuum, vacuum chamber, belt recovery and enzymatic recovery. The resulting mucosal material may be utilized as a healing composition. Mucosal layers produced from animals processed in accordance with the methods described herein have superior healing activities over mucosal preparations produced from animals processed by conventional freezing methods .

Numerous modifications and variations in practice of the invention are expected to occur to those skilled in the art upon consideration of the foregoing detailed description of the invention. Consequently, such modifications and variations are intended to be included within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A method for processing frozen edible marine animals comprising: partially thawing the animal for a time effective for providing a gut surface temperature of at least about 32'F; opening a body cavity of the animal; and removing entrails of the animals.

2. The method of claim 1 wherein the frozen edible marine animals are fish.

3. The method of claim 1 wherein the animal is partially thawed to a temperature of about 33 ^*F to about 46^*F.

4. The method of claim 1 further comprising removing a blood line of the animal.

5. A method for processing edible marine animals comprising: stunning the animals in an aqueous medium; exsanguinating each of the animals in an aqueous medium; immersion freezing the animals by contacting the animals with a liquid cooling medium having a temperature of below 32'F, ; maintaining ^"the animals in the cooling medium for a time period effective for providing a core temperature of 25 "F in the animal; partially thawing the animal for a time effective for providing a gut surface temperature of at least about 32 "F; opening a body cavity of the animal; and removing entrails of the animals.

6. The method of claim 5 wherein the frozen edible marine animals are fish.

7. The method of claim 5 wherein the animal is partially thawed to a temperature of about 33 'F to about 46^*F.

8. The method of claim 5 further comprising removing a blood line of the animal.

9. A process for recovering roe comprising: stunning a fish containing roe in an aqueous medium; exsanguinating each of the fish in an aqueous medium; immersion freezing the fish by contacting the fish with a liquid cooling medium having a temperature of below 32'F, ; maintaining the fish in the cooling medium for a time period effective for providing a core temperature of 25'F in the fish; partially thawing the fish for a time effective for providing a gut surface temperature of at least about 33'F; opening a body cavity of the fish; and removing the roe .

10. The method of claim 9 wherein the animal is partially thawed to a temperature of about 33 "F to about 46^*F.

11. The method of claim 9 wherein the roe is thawed in a brine solution.

12. A method for producing a proteinaceous product from edible marine animals comprising: stunning the animals in an aqueous medium; ^■ exsanguinating each of the animals in an aqueous medium; immersion freezing the animals ^"by contacting the animals with a liquid cooling medium having a temperature of below 32 "F, ; maintaining the animals in the cooling medium for a time period effective for providing a core temperature of 25 'F in the animal; thawing the animal to a temperature of at least about 33¹F; processing the animal or animal parts into a ground condition; hydroIyzing protein; and recovering the protein.

13. The method of claim 12 wherein the animal is partially thawed to a temperature of about 33 "F to about

46'F.

14. A method for producing an omega-3 fatty acid composition from edible marine animals comprising: stunning the animals in an aqueous medium; exsanguinating each of the animals in an aqueous medium; immersion freezing the animals by contacting the animals with a liquid cooling medium having a temperature of below 32'F, ; maintaining the animals in the cooling medium for a time period effective for providing a core temperature of

25 "F in the animal ; thawing the animal to a temperature of at least about 33 'F or greater; and extracting omega 3 fatty acid from the animal.

15. The method of claim 14 wherein at least a portion of the liver is removed from the animal and omega

3 fatty acids are extracted from the liver portion.

16. A method for producing a healing composition from edible marine animals comprising: stunning the animals in an aqueous medium; exsanguinating each of the animals in an aqueous medium; immersion freezing the animals by contacting the animals with a liquid cooling medium having a temperature of below 32 'F, ; maintaining the animals in the cooling medium for a time period effective for providing a core temperature of 25 'F in the animal; thawing the animal to a temperature of at least about 33 'F or greater; and removing a mucosal layer of the marine animal .