FI20235032A1 - Process for the production of a food product - Google Patents

Abstract

A method for producing a fish product suitable for human consumption from undervalued parts of fish material using extrusion is presented.

Description

METHOD OF PRODUCING A FOOD PRODUCT

FIELD OF THE INVENTION

The present invention relates to a method of producing a food product.

More particularly, the invention relates to a method of producing a food product by extrusion from a fish material including undervalued parts of fish.

BACKGROUND OF THE INVENTION

Extrusion is widely used in the manufacture of various food products.

Broadly, extrusion is a continuous process which uses an extruder having one or two screws. The extruder provides transport, compression, mixing, cooking, shear- = ing, heating, cooling and shaping of raw material to final products.

Anni Nisov et al, Comparison of Whole and Gutted Baltic Herring as a

Raw Material for Restructured Fish Product Produced by High-Moisture Extrusion

Cooking, Foods 2020, 9 1541, pages 1-12, discloses the microbiological safety, sen- sory properties and structure properties of whole ungutted fish and gutted fish in — high-moisture extrusion cooking with incorporation of plant protein.

BRIEF DESCRIPTION OF THE INVENTION

It has now been found that a food product for human consumption with satisfactory organoleptic properties, such as appealing taste and good mouthfeel, may be produced from undervalued parts of a fish material by extrusion without a stabilizing material. The fish material be whole fish or gutted fish, or only hard tis- sues of a fish material. The invention thus provides a method of producing a valu- able food product with consumer acceptable organoleptic properties from un un- dervalued fish material.

Q In the context of the invention, the term “stabilizing material-free”

N 25 — means that the food product does not contain a plant protein material, an animal 5 protein material, egg protein, a plant carbohydrate material, plant fiber material or - any mixture of said materials. x The invention provides a sustainable method in which whole or gutted

E fish is effectively used in the production of a ready-to-consume food product for & 30 human consumption providing environmental benefits. 2 The invention also provides a method in which undervalued parts of a

S fish material or of low hygienic guality may be used providing economic benefits in that the product can be offered at a lower cost.

The invention further provides a method of producing a food product with an increased nutritional value.

Further, the invention provides a method of producing a food product which enables reduction of global meat production providing environmental ben- efits.

The invention also provides a method of producing a food product with high microbiological quality and substantially eliminated Salmonella bacteria.

The food product can be used as an ingredient or an extender and com- bined with other food materials to produce a wide variety of food compositions.

The food product produced by the method of the invention is also suit- able as an animal feed.

In an aspect, the present invention provides a method for producing a food product from a fish material without a stabilizing material including under- valued parts of fish.

In an aspect, the invention provide a food product obtainable by the method of the invention.

In a further aspect, the invention provides a food composition compris- ing a food product produced by the method of the invention.

In an aspect, the invention provides use of a food product produced by the method of the invention in the food compositions.

In further aspect, the invention provides an apparatus comprising means for implementing the method of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 generally illustrates a process flow diagram of an embodiment of the method of the invention.

Figure 2 illustrates an embodiment of an apparatus of the invention.

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N DETAILED DESCRIPTION OF THE INVENTION

O In an aspect, the present invention provides a method of producing a = stabilizing material-free food product, comprising = - providing a fish material containing hard tissues, * 30 — - optional grinding the fish material with a grinder having a hole size of at most 2 & mm to provide a fish mass, 2 - subjecting the fish material to a first colloid milling to provide a colloid milled fish mass, - subjecting the colloid milled fish mass to an extrusion to provide an extruded mass,

- subjecting the extruded mass to a second colloid milling to provide a milled ex- truded mass as a food product.

Figure 1 illustrates an embodiment of the method of the invention. The dotted line in figure 1 illustrates optional method steps. The method may include further optional method steps not shown in the figure.

The fish material suitable for use in the method of the invention in- cludes any fish species suitable for human consumption, for example salmon or

Baltic herring. In an embodiment, the fish material is whole fish or gutted fish. In an embodiment, the fish material comprises hard tissues of fish, i.e, fish bones, scales, head or fins. In an embodiment, the fish material consists of hard tissues selected from fish bones, scales, head, fins and any mixture thereof. The fish mate- rial can also comprise or consists of skin. In an embodiment, the fish material con- tains up to about 90 wt-% of hard tissues selected from fish bones, scales, head and fins. In an embodiment, the fish material contains about 30 wt-% to about 90 wt- 9% of hard tissues.

In the method, the fish material comprising hard tissues is optionally ground with a grinder having a hole size of at most 2 mm to provide a fish mass.

In an embodiment, the method of the invention comprises a pH adjust- ment step. In an embodiment, the pH of the fish material is adjusted to about 2 to about 6 with a food grade acid. The food grade acid can be citric acid.

The fish material is subjected to a first colloid milling step to mince the particles included in fish material to smaller pieces. Generally, “colloid mill” is a machine which has a high-speed rotor and a stator providing superfine grinding results along with simultaneous emulsifying, homogenizing, and dispersing. The rotor pushes the material into small gaps between the rotor and stator causing in- n tense mechanical shear. In the presentinvention, colloid milling provides a homog-

AN enous, ultra-fine bone particles of bone-containing fish mass and beneficially en- = hances softening of bone particles in the subseguent wet extrusion. In an embodi- ? ment, colloid milling of the fish mass provides bone particles having an average - 30 particle size of about 50 um to about 200 um. However, there can be some individ-

E ual particles present having a bigger particle size.

N The colloid milled fish mass is then subjected to an extrusion to provide 3 a solid extruded mass. In an embodiment, the extrusion is performed at a moisture & of at least 20%. In an embodiment, the extrusion is a wet extrusion to provide an

N 35 extruded mass. In context of the present invention, the term “wet extrusion” means that the colloid milled fish mass to be extruded has a moisture content of at least

30%. In an embodiment, the moisture content of the colloid milled fish mass is in the range of 30% to about 70%. If the moisture content is lower than 30%, it may be difficult to carry out the extrusion process, since the colloid milled fish mass in the extruder is dry. On the other hand, if the moisture content is higher than 70%, liquid may undesirably separate from the dry matter of the colloid milled fish mass.

The extrusion may be carried out with a single-screw or twin-screw ex- truder. Shearing and tearing combined with moisture in the extrusion step causes softening of the hard tissues of fish and provides a unique structure to the final food product.

In an embodiment, the extrusion is performed at a temperature of about 100°C to about 400°C. Depending on the extruder used in the method, the extruder has to contain at least one heating segment where the temperature is at least 100°C. In addition, there may be further heating segments where the extru- sion may be performed below 100°C, e.g., at 70°C. In an embodiment of the inven- — tion, an extruder is used which contains several heating segments each operated at a different temperature. In an embodiment, the temperature of the heating seg- ments increases when the mass moves forward in the extruder.

The duration of the extrusion step is dependent on the apparatus con- struction and settings.

In an embodiment, the extrusion in the method is performed using about 100 rpm to about 1000 rpm speed. In another embodiment, the extrusion is performed using about 200 rpm to about 600 rpm speed. In an embodiment, about 500 rpm is employed in the extrusion.

In an embodiment, the extrusion provides an extruded mass having a temperature of atleast 100°C. n In an embodiment, the extruded mass is cooled to a temperature of

AN about +60°C to about -30°C. In an embodiment, cooling of the extruded mass is per- = formed in an extruder before the extruded mass is discharged from the extruder. ? Cooling in the extruder is conveniently carried out in the cooling die. When the ex- - 30 — trudedmassiscooledin the extruder, the temperature of the mass discharged from

E the extruder may range from about 1°C to about 80°C, or from about 1°C to about

N 60°C. In an embodiment, the temperature of the extruded mass is in the range from 3 about 30°C to about 60°C. & In another embodiment of the invention, the colloid milled fish mass in

N 35 the extruder is pressed thorough a hole, which may be smaller than or equal to the cylinder area in the end of the extrusion cylinder. Extruded mass loses a portion of water steam when it exits the process, if the temperature is more than 100°C. The mass has a different taste, smell, structure (viscosity, cutting properties etc.), and itreacts differently in post-processing compared with a process involving a cooling die step. 5 The extrusion of the colloid milled fish mass provides a solid extruded mass which is further subjected to a second colloid milling to further mince the particles in the extruded mass and to improve the sensory properties of the ob- tained food product. The second colloid milling may be the same as or different from the first colloid milling. In an embodiment, water and/or oil is added to the extruded mass before colloid milling to enhance the mincing effect of colloid mill- ing.

The second colloid milling of the solid extruded mass provides a food- grade product with appealing sensory properties which is ready to be consumed as such. Two times colloid milled food product exhibits a smooth mouth feel with- out observable bone particles present. The food product shows an average particle size of at most 50 um. In an embodiment, the average particle size is in the range of about 25 um to about 50 pm. In another embodiment, the average particle size is in the range of about 1 um to about 15 um.

Extrusion process decreases microbial load a fish material enabling use of fish of low hygienic quality. Microbial load is reduced by approximately 1000- 1012 fold during the process.

The extruded food product produced by the method of the invention may imitate the texture, flavour, and mouthfeel of meat.

The method of the invention provides a food product which exhibits an increased nutritional value. By using calcium-containing parts of a fish material,

NN i.e., bones, the calcium content of the food product produced by the method is in-

N creased. In an embodiment, the food product has a calcium content of about 0.2 wt- = % to about 4.0 wt-%. In another embodiment, the calcium content of the food prod-

O uct is about 0.3 wt-% to about 2.0 wt-%. In a further embodiment, the calcium con- - 30 tent of the food product is about 1.2 wt-% to about 1.5 wt-%.

E In an embodiment, the food product is heat-treated at a temperature

N ranging from about 110°C to about 400°C to further improve sensory properties 3 and mouthfeel of the product. The heat treatment may be carried out, e.g, by cook- & ing in oil, e.g, at 150-300°C, grilling, pan frying, drying by heat, e.g., at 200-400°C,

N 35 freeze drying below -70°C, microwaving or infrared radiating.

Extrusion of a fish material, such as whole fish including undervalued parts, such as fish bones and other hard tissues, together with heat treatment pro- vides a ready-to-eat food product for human consumption which shows unique, appealing taste and structure, and mouthfeel.

The sensory properties of the food product may be further improved by adding ingredients typically used in food manufacture to the food product pro- duced by the method of the invention, e.g, flavouring agents, aromas, salt, emulsi- fiers, carbohydrates, fibres, oils and fats, etc.

The extruded food product produced by the method of the invention may be combined with other food materials to provide a wide variety of food com- positions having different appearance, taste and structure. Thus, in an aspect, the invention provides use of a food product produced by the method of the invention as an ingredient or extender in the production of food compositions. The food prod- uct produced by the method of the invention may be included in the foodstuff in an amount up to about 50 wt-% without imparting any negative effect on the sensory properties of the food composition.

In an embodiment, the food product is mixed with water in a ratio of 3:1 (w/w) to provide an aqueous fish mass. Salt may be added to an aqueous fish mass, e.g. to provide a salt content of about 2 wt-% to the mass. The aqueous fish mass may then be added to a fish fillet by needling it inside the fish fillet, e.g., in a ratio of 1:10 (w/w). Needling is appropriately performed in several injection steps.

In another aspect, the invention provides a food composition compris- ing a food product produced by the method of the invention.

In a further aspect, the invention provides an apparatus for implement- ing the method of the invention, comprising means for implementing the method n of the invention. An embodiment of the apparatus of the invention is illustrated in

AN figure 2. The dotted line illustrates optional units. The apparatus may include fur- = ther optional units not shown in the figure.

P In an embodiment, the means comprises - 30 - an optional meat grinder for grinding a fish material to provide a fish

E mass,

N - a first colloid mill optionally connected with the meat grinder and con- 3 figured to receive the fish mass, & - an extruder connected with the first colloid mill and configured to re-

N 35 ceive the colloid milled fish mass to provide an extruded mass, - a second colloid mill connected with the extruder and configured to receive the extruded mass to provide a food product.

The following examples are presented for further illustration of the in- vention without limiting the invention thereto.

The calcium content of the food product was measured according to standard SFS-EN ISO 11885, 2009.

The level of aerobic microorganisms was measured according to stand- ard NMKL 86:2013.

The amount of Salmonella was measured according to ISO/DIS 20976- 2.

Example 1 100 kg of fish (gutted Salmon) containing about 90% in total of head, scales and fins, and 10% of muscle mass was colloid milled to a fine fish mass hav- ing a diameter of hard tissue particles of about 100 pm.

The fine fish mass was kept at approximately 4°C. The mass was then loaded to a silo connected to a conveyor screw that was connected to a hopper with approximately 30 liters of volume. The mass was led from the hopper with an auger and a screw to an extruder in a controlled manner at about 55 kg/h. The moisture content of the mass was about 65 wt-%. The mass was extruded at 170 rpm. Heat- ing zones of the extruder were adjusted to a temperature of 60°C, 70°C, 80°C, 100°C, 120°C, 150°C and 170°C.

The extruder was provided with a cooling die. The first zone of the cool- ing die was set to 35°C and the last zone to 35°C. The extrusion process took about one minute.

Extruded, solid fish mass exited the cooling die at a temperature of less — than 100°C. Only a small amount of steam was released in the process. Solid fish

NN mass and some amounts of separated oil exited the end of the cooling die.

N The level of aerobic microorganisms of the solid fish mass obtained = from the extrusion was measured at 30°C/72 h. The solid fish mass showed < 100 ? pmy/g, while the fine fish mass subjected to extrusion showed more than 1 000 - 30 000 pmy/g. The measured level of aerobic microorganisms indicates that a food

E grade product for human consumption was obtained.

AN Water was added to the solid fish mass each in aratio of 1:10 (w/w) and 3 was left to be absorbed by the mass at 30°C for 20 minutes and mixed. Batches of & the mass were then milled with a colloid mill. The colloid milling provided a milled

N 35 fish mass which is a ready-to-consume food product with appealing sensory prop- erties.

The food product had a calcium content of 2 wt-%.

The food product exhibited 7-log reduction of Salmonella bacteria indi- cating that Salmonella was completely eliminated.

The colloid milled fish mass was mixed with water in a ratio of 3:1 (w/w) to provide an aqueous fish mass. Salt was added so as to provide an aqueous fish mass having 2 wt-% of salt. The aqueous fish mass was added to Salmon fillet at 2°C by needling it inside the Salmon fillet in a ratio of 1:10 (w/w) in total 50 separate injection steps.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The inven- tion and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

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Claims (13)

1. A method of producing a stabilizing material-free food product, com- prising - providing a fish material containing hard tissues, - optional grinding the fish material with a grinder having a hole size of at most 2 mm to provide a fish mass, - subjecting the fish material to a first colloid milling to provide a colloid milled fish mass, - subjecting the colloid milled fish mass to an extrusion to provide an extruded mass, - subjecting the extruded mass to a second colloid milling to provide a milled extruded mass as a food product.

2. The method of claim 1, wherein the fish material containing hard tis- sues is whole ungutted fish or gutted fish containing at least one of bones, scales and fins.

3. The method of claim 1 or 2, wherein the fish material contains up to 90 wt-% of hard tissues selected from fish bones, scales, head and fins.

4. The method of any one of the preceding claims, wherein the pH is ad- justed to about 2 to about 6 with a food grade acid before extrusion.

5. The method of any one of the preceding claims, wherein the first col- loid milling provides a colloid milled fish mass including particles of a particle size of about 50 um to about 200 um.

6. The method of any one of the preceding claims, wherein the extrusion is performed at a temperature of 100°C to about 400°C.

7. The method of any one of the preceding claims, wherein the extrusion en is performed at a moisture content of at least 20%.

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8. The method of any one of the preceding claims, wherein the extrusion + is a wet extrusion in which the mixture of the colloid milled fish mass and the sta- ? bilizing agent has a moisture content of about 30 wt-% to about 70 wt-%. > 30

9. The method of any one of the preceding claims, wherein the temper- = ature of the extruded mass is at least 100°C. N

10. The method of any one of the preceding claims, wherein the food 3 product shows an average particle size of at most 50 um, specifically about 25 um O to about 50 um, more specifically about 1 um to about 15 um.

11. The method of any one of the preceding claims, wherein the food product has a calcium content of about 0.2 wt-% to about 4.0 wt-%, specifically about 0.3 wt-% to about 1.5 wt-%, more specifically about 1.2 wt-% to about 1.5 wt-%.

12. A food composition comprising a food product produced by the method of any one of claims 1-11.

13. An apparatus comprising means for implementing the method of any one of claim 1-11, wherein the means comprises - an optional meat grinder for grinding a fish material to provide a fish mass, - a first colloid mill optionally connected with the meat grinder and con- figured to receive the fish mass, - an extruder connected with the first colloid mill and configured to re- ceive the colloid milled fish mass to provide an extruded mass, - a second colloid mill connected with the extruder and configured to receive the extruded mass to provide a food product. 0 N O N > I a a N 0 O LO ™ N O N