A METHOD FOR THE FREEZING OF MOULDABLE FOOD PRODUCT MASSES TO FORM BLOCKS, AND A FREEZING MOULD FOR USE IN CARRYING OUT THE METHOD

Abstract: A mouldable food product mass, e.g., a fish product mass in the form of packed fish fillets or separated fish meat, is frozen to form blocks by filling a predetermined quantity of the mass into a freezing mould (1, 2) with inwardly domed cover (6) and/or bottom (1) and placing the mould in a freezer (8). The inwardly downed shape (9) is so selected that under the influence of the expansion of the mass caused by freezing, the cover and/or bottom is flattened to substantially plane shape (10). Thereby blocks of regular configuration with plane faces are obtained. Such blocks can without waste be cut into rods of uniform size.

Description: A METHOD FOR THE FREEZING OF MOULDABLE FOOD PRODUCT MAS¬ SES TO EORM BLOCKS, AND A FREEZI NG MOULD FOR USE IN CARRY- ING OUT THE METHOD. The invention relates to a method for the freezing of ould- able food product masses to form blocks, where the mass is filled into a freezing mould which is then placed in a freezer, e.g. a plate free¬ zer or a tunnel freezer, and upon freezing is taken out and handled for expelling the frozen block. A particularly important example of food product masses suitable for freezing into blocks is fish product masses in the form of packed fish fillets or so-called separated fish meat. However, the method can also be used for the freezing of packed pieces of meat or minced meat. A ouldable food product mass may, besides fish or meat, also comprise other edible products in mixture with or as addi- tions to fish or meat. In the following, the invention will be described in particular with reference to its application to the fish processing industry, which is at present believed to be its most important field ' of application, but it will be understood that fish products have only been chosen as an illustrative example of the mouldable food product masses suitable for processing in accordance with the principles of the invention. Within the fish processing industry it is customary to freeze mouldable fish product masses in freezing moulds to form blocks of relatively large size. These blocks are subsequently subdivided into bars, either in the same factory or after shipment to another location. The subdivision takes place by performing cuts in all co-ordinate directions by means of special sawing machines especially devised for the purpose. The bars are individually wrapped and constitute the commercial product offered to the consumers , it is normally a require- ment that each and every rod presented for sale should have a weight not below a specified minimum value. For freezing the blocks it is customary to use a cardboard box which is placed in the mould, whereafter a predetermined quanti¬ ty of fish product mass is filled into the box, and the latter is closed by means of a cardboard cover belonging to the box. After the freez¬ ing, the freezing mould is removed from the freezer, e. g. a plate freezer, and is turned upside down, whereafter the frozen block in its cardboard box is expelled by means of one or more pusher rods which are passed through holes in the bottom of the mould . OMPI The freezing of the block starts along the perimeter of the freezing mould and then progresses inwards towards the middle. Owing to the expansion of the fish product mass caused by freezing, the mass will therefore be pressed upwards progressively from the perimeter towards the middle, so that the upper surface of the block will assume a domed shape. In the cutting of bars from such a block with a domed surface there will either occur a waste, or else the bars cut from the uppermost slice will have a non-uniform thickness. Since the thinnest bars must keep the prescribed minimum weight, it will be inevitable in the latter case, that some of the bars cut from the uppermost slice will have an excess weight, which again means that an excess quantity of fish product mass must be used when starting freezing of the block. This detracts from the economy of the process and will ultimately result in an increase of the sales price to the consumer required for making the production profitable. It is the object of the invention to avoid the drawback men¬ tioned. With this object in view, according to the inventio ' n, a freezing mould is used which has either an inwardly domed cover, to be applied after the filling step, and/or an inwardly domed bottom, the domed shape being so selected that under the influence of the expansion of the mass caused by the freezing the cover and/or bottom becomes flattened to substantially plane shape. In this manner it becomes possible to produce blocks having a regular shape with plane faces, so that these blocks can be cut into rods of uniform shape and uniform weight without any waste. The mould and cover are preferably made from stainless steel, which is an elastic material, in any case it is highly advantage¬ ous that the domed element (cover and/or bottom) should consist of an elastic material which has the inwardly domed shape In its non-load- ed state so that it will return to the inwardly domed shape when the freezing and expelling of the block have been completed. In carrying out the invention it is perfectly possible, if de¬ sired, to use a cardboard box with cover, like in the known method, seeing that the cardboard material can easily adapt itself to the inwardly domed shape of the mould cover and/or bottom and the straightening out of the cover and/or bottom during freezing. However, in most cases it will be preferred to omit the cardboard box so as to avoid the ensuing expenses and complications in the handling, not OMPI least in respect of removal of the cardboard before working up the block to the final commercial product. The invention also relates to a freezing mould for use in carrying out the method . According to the invention, such a mould comprises a tray having side walls, a bottom and a cover to be applied to the open top of the tray after a predetermined quantity of the food product mass to be frozen has been filled into the box, said bottom and/or said cover having an inwardly domed shape so selected that it will be flattened to substantially plane shape under the influence of the expansion of the contents of the box taking place under the influence of freezing of the box with contents in a freezer. The invention will now be further described with reference to the accompanying drawings, in which Fig. 1 is a perspective view of one embodiment of a freez- ing mould for use in carrying out the invention, Fig. 2 is a perspective view of a cover belonging to the freezing mould of Fig . 1 , Fig. 3 is a longitudinal section of the cover of Fig . 2, Fig. 4 is a cross section of the cover of Figs. 2 and 3, Fig. 5 is a longitudinal section of the freezing mould of Fig . 1 along the line V-V in Fig . 6, Fig. 6 is a cross section of the freezing mould of Figs. 1 and 5 along the line VI -VI In Fig . 5, Fϊg. 7 is a cross section of the freezing mould of Fig. 1 with the cover of Fig . 2 applied thereto and plac¬ ed in a plate freezer, Fϊg . 8 is a longitudinal section of another embodiment of a freezing mould along the line VI i ϊ— VI 11 in Fig.9, and Fϊg. 9 is a cross section of the freezing mould of Fϊg. 8 along the line IX- IX in that figure. The freezing mould shown in Fig. 1 has a bottom 1 and side walls 2 constructed at their upper end with a marginal fold 3. The bottom 1 has two square holes 4 in which closing tablets 5 may be placed as illustrated in Fϊg. 5. The tablets 5 fit loosely in the holes 4 and have thin flat heads 5 a, which abut the bottom 1 from above and completely cover the holes 4. To the freezing mould belongs a cover 6, Fig . 2, which has downwardly bent marginal flanges fitting around the marginal fold 3 of the mould. In its non-loaded state the cover 6 has an Inwardly domed shape which is best seen in Figs. 3 and 4. The freezing of a block of a fish product mass with use of the mould and cover illustrated takes place as follows: After the tablets 5 have been placed in the holes 4, a predetermined quantity of a mouldable fish product is filled into the mould. The mass may thereafter be further compacted by means of a plunger. This operation may take place in a vacuum atmosphere by means of which any free air present In the mass in the form of voids or interstices is removed to the greatest possible extent, seeing that voids and interstices in the frozen block would jeopardize its homoge¬ neity and thereby the uniformity of weight of rods to be cut from the block as previously explained. The removal of free air may be further¬ ed by providing venting holes or slots in the plunger. The described removal of free air may be dispensed with, if the food product concern¬ ed contains very fittle free air, or no great emphasis is placed on the homogeneity of the frozen block, e.g. if it Is to be sliced Into relative¬ ly thick slices. After the food product mass has been filled into the mould and has been processed, as required, in the manner described, the cover 6 is applied without fastening, and the mould is placed in a freezer, e.g. a plate freezer 8, Fig. 7. Before freezing commences, the cover 6 has the Inwardly domed configuration illustrated by the dotted line 9 In Fϊg. 7. When the fish product mass expands during freezing, the cover becomes flattened to substantially plane shape as indicated in full line at 10. Should the expansion go slightly beyond the point where the cover has just become flattened, the cover may lift slightly from the mould against the hydraulic pressure of the plate freezer, so there is no danger of bursting of the mould, the cover, or the frozen block. If a tunnel freezer Is used instead of a plate freezer, a number of moulds, each with its cover, may be stacked upon one another and may be resϋiently clamped together, so that a slight lifting of the covers from the moulds is also possible in this case. It is to be understood, however, that it is preferable to adjust the parameters in such a manner, that in normal operation the expansion by freezing is completed immediately before the cover assumes mathematically exactly plane shape so that no lifting of the cover takes place, but owing to the possibility of lifting of the cover this condition is not critical. When the freezing is completed, the freezing mould is taken out and turned upside down, whereafter the block is expelled by means of pusher rods that are pressed against the tablets 5 and through the holes 4. When relieved from the pressure in the plate freezer, the co¬ ver re-assumes its inwardly domed shape, and both the freezing mould and the cover are then ready for the freezing of a new block. Instead of the holes with the closing tablets the bottom may be constructed with a valve arrangement, through which compressed air can be injected for expelling the frozen block. In the embodiment of Figs. 8 and 9, the mould is construct¬ ed with an inwardly domed bottom 11. This may be used in combination with a flat cover or with the inwardly domed cover of Figs. 2-4. In the latter case the domed shapes will have a correspondingly smaller depth, and the mechanical stresses produced by the flattening during freezing will be correspondingly lower. When using an inwardly domed bottom, which is flattened during freezing, expelling of the frozen block may be initiated by exert¬ ing a pressure on the central area of the bottom so as to make it tend to spring back to its domed shape. Preferably, this action is combined with a pneumatic expelling force obtained by injecting compressed air into the mould through holes in the bottom adjacent the periphery of the domed portion of the bottom. Fig. 8 shows the provision of such holes 12. They may in this embodiment be made so small that in most cases it will be unnecessary to close them by means of plugs to avoid or practically avoid the leaking out of liquid from the food product mass during the filling and handling of the mould before freezing sets in. E.g. in the case of fish fillets, when filling is commenced, each of the small holes will soon be closed by a fillet applying itself to the area of the bottom surrounding the hole.

Claims: C A I S: 1. A method for the freezing of mouldable food product masses, such as fish product masses in the form of packed fish fillets or separated fish meat, to form blocks, where the mass is filled Into a freezing mould, which is then placed in a freezer and upon freezing is taken out and handled for expelling the frozen block, c h a r a c ¬ t e r i z e d by using a freezing mould (1 , 2) having either an in¬ wardly domed cover (6), to be applied after the filling step, and/or an inwardly domed bottom (1), the domed shape being so selected that under the influence of the expansion of the mass caused by the freezing the cover and/or bottom becomes flattened to substantially plane shape. 2. A freezing mould for use in carrying out the method according to claim 1 for the freezing of mouldable food product masses, such as fish product mass in the form of packed fish fillets or separated fish meat, to form blocks, comprising a tray having side walls, a bottom, and a cover to be applied to the open top of the tray after a predetermined quantity of the food product mass to be frozen has been filled into the box, said bottom and/or said cover having an inwardly domed shape so selected that it will be flattened to substantially plane shape under the influence of the expansion of the contents of the box taking place under the influence of freezing of the box with contents in a freezer.

Inventors: NIELSEN-JEXEN OLE, NIELSEN-JEXEN, OLE
Applicants: NIELSEN JEXEN OLE, NIELSEN-JEXEN, OLE
Application year: 1983
Main classification: A23B4
IPC codes: A23B4, A23L1, A23L3, A23P1