GB2116829A

GB2116829A - Process and apparatus for treating small fish

Info

Publication number: GB2116829A
Application number: GB08207357A
Authority: GB
Inventors: Morgan Henderson Goodlad; George Robert Park
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1982-03-12
Filing date: 1982-03-12
Publication date: 1983-10-05
Also published as: IT1159368B; IT8367276A0; IT8353051V0

Abstract

Small fish can be skinned and intestines removed by putting the fish into contact with at least one rotary brush while immersed in a liquid and thereafter separating the fish from the liquid. The fish and liquid are placed in receptacle (1) containing a pair of contra-rotatable drivable brushes (4) so that the fish move in direction of arrows (7) and are skinned and degutted. A coarse sieve may be placed below the receptacle to hold the treated fish whilst skin, guts and liquid pass through. <IMAGE>

Description

SPECIFICATION Process and apparatus for treating small fish The present invention relates to a method and an apparatus for processing small fish, in particular for skinning small fish.

Since traditional fish such as cod and haddock nowadays have become rather expensive and are subject to catch quota, small fish such as sprat, sardine, capelin, pout and anchovy could be of growing interest if not the treatment of such fish for scaling, skinning and cleaning were prohibitively time-consuming and expensive.

US 3 806 616 discloses a method for removing the skin and scales of fish by precooking, perforating the skin and the scales, wetting with a caustic solution and thereafter spraying a liquid onto the fish for removing the superficial layer including skin and scales, but this method is not entirely satisfactory since the caustic solution affects the flavour of the fish, even after prolonged washing with water. The same is true for acid treatments for removing skin and scales such as disclosed in BE 832831.

There is a accordingly a continuous need for a simple and reliable method for skinning and scaling small fish whereby preferably simultaneously degutting and removal of the black membrane is obtained. A similar need exists for an apparatus for putting this method into practice.

The present invention concerns a method for the removal of fish skin, which is covered or not covered with scales, as well as of the subcutaneous fat, guts and black membrane (peritoneum). According to the invention the fish to be treated is put into contact with at least one rotary brush while immersed in a liquid until the skin and the intestines have been removed from the fish and thereafter the fish is separated from the liquid dispersion.

Both whole fish and headed fish can be treated. Since the removal of the intestines is more complete if headed fish is treated, this is to be preferred.

A more complete and selective removal of the skin and the subcutaneous fat is obtained if the fish prior to the treatment with the brushes is heat-treated in that it is subjected to a fluid medium of at least 60"C for a time sufficient to loosen the skin and the subcutaneous tissue but not to appreciably deteriorate the muscle tissue.

In a preferred embodiment this heat-treatment is effected by immersing the fish in an amount of water of the same magnitude at 90 C to its boiling point. A normal period for this heat-treatment is approximately 10 seconds; a longer treatment will result in cooking the muscle and a shorter treatment will require a lengthy brushing treatment.

The brushing treatment in itself is preferably effected by putting the fish into contact with at least one pair of contra-rotating brushes: the brushes mutually serve as a yieldable backing for the brushing treatement of the other one.

The invention also provides an apparatus for putting the invented method into practice.

This apparatus comprises a receptacle for containing a liquid and fish and agitating means for exerting an agitating action on the contents of that receptacle. According to the invention this apparatus also comprises at least one pair of contra-rotatably driveable brushes as agitating means, means for moving the contents of the receptacle with respect to the axes of these brushes and means for separating solids from the contents of the receptacle. The means for separating solids from the dispersion may comprise any suitable known separating means, such as a sieve, a grid and the like, provided the apertures are sufficiently large for allowing scales, gut fragments and skin fragments to pass but not the treated fishes.In a simple embodiment the means for moving the contents of the receptacle with respect to the axes of the brushes may be the brushes themselves, which when contra-rotating will cause a flume in the receptacle whereby the fishes are repeatedly brought into contact with these brushes.

In a preferred embodiment the receptacle is trough-shaped while at least one separating wall, which extends in a transverse direction in the receptacle, is movable to and fro with respect to the axes of the brushes, which axes are in pairs arranged in transverse planes. In this embodiment the fishes are repeatedly forced in an intimate contact with the brushes, whereby a quick and reliable result is obtained.

In a very easy embodiment which requires only little supervision and little treating time, the brushes are rotatably supported on a common support which is movable with respect to the receptacle. Preferably the receptacle is part of a circular channel, while the support is pivotable about the axis of said channel. In this embodiment only a simple motor means is required for moving the support and the brushes controlled by for instance two switches for reversing the direction of movement.

Very suitable the receptacle is provided with an outlet, debouching at the separating means. In a very practical embodiment the receptacle is a cylindrical cup with a central aperture in the bottom, plugged by a removable support for the frame bearing the brushes, which support is also cylindrical but of a smaller diameter than the cup and-concentric therewith. On removal of the support the hole is freed and the contents of the receptacle can flow onto the separating means arranged beneath the hole.

The invention will be clucidated in the following description of some preferred embodiments, which are shown in the appurtenant drawings for the purpose of illustration only and not for restricting the invention.

Figure 1 is a diagrammatic top view showing a simple embodiment of an apparatus according to the invention.

Figure 2 ia a vertical section taken along the line ll-ll of Fig. 1.

Figure 3 is a diagrammatic top view showing an upscaled embodiment of an apparatus according to the invention.

Figure 4 is a vertical section taken along the line IV-IV of Fig. 3.

Referring to Figs. 1 and 2 a diagrammatic representation of a simple, small scale apparatus according to the invention is shown. In a receptacle, being an open topped cylindrical container 1 having its axis in a vertical position, two rotary brushes 2 are arranged. Both brushes 2 have a straight central core 3 bearing sidewardly extending brush threads 4.

The vertical cores 3 are supported in a common driving assemtly in such a manner that the brushes 2 extend to the bottom of the container and that the cylinder surfaces described by the extremities of the brush threads 4 are just or almost touching each other.

The driving assembly 5 comprises a motor means and gearing, such that the brushes 2 are contra rotatable as indicated by the arrows 6 in Fig. 1. When the brushes 2 are rotating in this sense a flume will be generated in the container as depicted by the arrows 7.

Figs. 3 and 4 relate to an apparatus of increased capacity. A cylindrical, cup shaped container 8 is provided with a central aperture 9 in its bottom wall. Below the aperture 9 a coarse sieve 10 is arranged for separating treated fish from treating liquid containing intestines, skin, scales and fat. This liquid is caught by a vessel 11 underneath the sieve 10.

The aperture 9 is plugged by a removable cylindrical support 1 2 which is concentric to the container 8 and which together with the container defines an annular channel 1 3 for containing fish and treating liquid. In this channel a radial separating wall 14, whch is preferably perforated to allow liquid to pass and to prevent fish from passing, extends between the cylindrical walls of the container 8 and the support 1 2. Four pairs of contrarotatably drivable brushes 1 5 are supported in a common frame 16, which is pivotable about the axis of the channel 1 3. Said frame is supported on the support 12, which may comprise the motor for pivoting the frame.

The pivoting movement, as indicated by the double arrow 1 6 is controlled in such a manner that the brushes 15, which extend into the channel, are moved through the channel until the separating wall 14 is reached and is thereafter reversed until the other side of this wall is reached and the movement is reversed again.

The apparatus as described hereinabove are used as follows: an amount of small fishes, preferably decapitated, is dropped into an equal amount of hot water at 90"C. After 10 seconds the fishes are removed from said water and put into the container 1 or 8 of the apparatus together with an equal amount of cold tap water. Thereafter the rotary brushes are set in motion for sufficient time to remov scales, skin, gut and black membrane, together with a considerable portion of the subcutaneous fat. Thereafter the mixture is removed from the container and the treated fishes are separated from the process liquid.

After washing the treated fishes can be deboned in any conventional manner. Gut, skin and scales may be separated from the process liquid, from which the fat may be isolated.

Claims

1. A method for processing small fish comprising removing at least the skin characterized in that the fish is put into contact with at least one rotary brush while immersed in a liquid until the skin and the intestines have been removed from the fish and thereafter the fish is separated from the liquid dispersion.

2. A method according to claim 1, characterized in that the beheaded fish is treated.

3. A method according to claim 1 or 2, characterized in that the fish is previously subjected to a fluid medium of at least 60"C for a time sufficient to loosen the skin and the subcutaneous tissue but not to appreciably deteriorate the muscle tissue.

4. A method according to claim 3, characterized in that the fish is immersed in an amount of water of the same order of magnitude at 90"C to its boiling point.

5. A method according to any claim 1 to 4, characterized in that the fish is put into contact with at least one pair of contra-rotating brushes.

6. Apparatus for processing small fish, comprising a receptacle for containing a liquid and fish and agitating means for exerting an agitating action on the contents of the receptacle, characterized in that at least one pair of contra-rotatable drivable brushes as agitating means, means for moving the contents of the receptacle with respect to the axes of these brushes and means for separating solids from the contents of the receptacle are provided.

7. Apparatus according to claim 6, characterized in that the receptacle is trough-shaped and in that at least one separating wall, extending in a transverse direction in the receptacle, is movable to and with respect to the axes of the brushes, which axes are in pairs arranged in transverse planes.

8. Apparatus according to claim 6 or 7, characterized in that the brushes are rotatably supported on a common frame, which is movable with respect to the receptacle.

9. Apparatus according to claim 6, 7 or 8, characterized in that the receptacle is part of a circular channel, while the frame is pivotable about the axis of said channel.

10. Apparatus according to any of the claims 6 to 9, characterized in that the receptacle is provided with an outlet, debouching at the separating means.

11. Apparatus according to claim 10, characterized in that the receptacle is a cylindrical cup with a central hol in the bottoms, plugged by a removable support for supporting the frame bearing the brushes, which support is also cylindrical but a smaller diameter than the cup and concentric therewith.