METHOD OF MAKING A FOOD PRODUCT
This invention relates to a method of making a processed food product.
According to one aspect of the invention there is provided a method of making a processed food product from food pieces (e.g. in cut, sliced, or minced form), which comprises: admixing a binder with the food pieces, forming the mixture of food pieces and binder into a desired shape to provide a formed product, and then subjecting the formed product to high frequency vibration in the presence of a setting solution for setting the binder.
The setting substance may be brought into contact with said mixture after it has been formed into said formed product. It could however also be brought into contact with the product before it has been formed. For example, the method could comprise admixing the binder with the food pieces, crust-freezing the mixture of food pieces and binder, and then adding the setting substance prior to forming.
The setting substance may be in the form of a solution which is injected into the formed product and may, if desired, also be contacted with the outside surfaces of the formed product. If the product is in a thin enough form however, it may simply be immersed in a setting solution, doing away with the need for the injection.
The setting solution may be injected into the formed product by means of injection needles which are inserted into and withdrawn from the formed product. It could however also be injected in a needle-less manner by forming the solution into high pressure jets which penetrate the product. An alternative method would be to have fixed needles or other nozzles which are mounted on slender supports so that their outlets are inside the product, the
product during operation moving past the slender supports.
The frequency of the vibration may be in the sonic or ultrasonic range. The frequency of the vibration may be in the range of 4 to 40 kHz, and preferably in the range of 5 to 8 kHz. The food pieces may be of meat. The meat can be the meat of any animal such as poultry, fish, or red meat. Alternatively, the food pieces can be selected from the group consisting of fruit, vegetables, cereals, and nuts.
According to another aspect of the invention there is provided a method of making a processed food product from food pieces, which comprises: admixing a binder with the food pieces, forming the mixture of food pieces and binder into a desired shape to provide a formed product, and then injecting a setting solution for setting the binder into the product. The invention will now be described in more detail, by way of example, with reference to the accompanying drawings. In the drawings: Figure 1 is a flow chart illustrating a method of making a processed meat product in accordance with the invention; and Figure 2 is a longitudinal section through the food product while it is in the process of being made.
EXAMPLE:
A FOOD PRODUCT INCORPORATING MEAT:
As a starting point, fresh meat is deboned and visually graded in terms of water, fat, protein, and collagen content, and, if necessary, cut into strips, cut into cubes of 1 to 3 cm, minced, or otherwise reduced in size. If frozen meat is used, it is first defrosted before being reduced in size. The meat pieces are then mixed with a conventional binder in the form of a gel. Mixing takes place in a
mixer and is to ensure that the binder is evenly distributed throughout the mixture. The mixture is then formed into the desired shape by moulding or extrusion. Mixing and forming conveniently takes place in a conventional mixer of the kind used in the meat industry, these having an extruder nozzle through which the product, after mixing can be extruded.
A setting solution in the form of brine is then brought into contact with the formed product. This can be done by injecting the setting solution into the formed product. Alternatively, or in addition, it can be done by bringing the setting solution into contact with the outside surfaces of the formed product, for example through immersing the formed product in a bath of the setting solution. Injection of the setting solution into the product may take place by means of a ganged row of injection needles, the product being moved along a path transverse to the row. The spacing between the points at which setting solution is injected should be as close as possible in order to bring the setting solution into as intimate as possible contact with the product throughout its volume. Because it is difficult, for practical reasons, to space the needles closer together than about 13 mm, two or more rows of ganged needles may be provided, the rows being spaced along the path, and the needles of one row being offset laterally with respect to the needles of the other row or rows. Alternatively, there may be a row of needles which extends diagonally, i.e. in a direction smaller than 90° to the direction of travel of the product. This will allow the needles in the (or each) row to be spaced apart by more than 13 mm, yet allow for the distance between adjacent injection points to be smaller, e.g. about 8 mm.
Once the binding solution has been injected into the product the product is subjected to sonic/ultrasonic vibration. The frequency of the vibration is determined by the depth to which it is
desired that the vibration should penetrate the product. The lower the frequency, the deeper the vibration penetrates the product. The frequency of the vibration also has an effect on the speed at which setting of the binder takes place, the greater the frequency the greater the speed at which the setting takes place. As a consequence, if the frequency is too low the effect of the vibration in accelerating the setting of the binder diminishes to an unacceptable level. In the case of a formed product which has a thickness of 5 cm a frequency of about 5 to 8 kHz has been found to give good results.
The product may then, immediately thereafter, be sliced, coated and/or flash fried, vacuum packed, etc. Alternatively, the product may be refrigerated and cut later.
The flow chart of Figure 1 illustrates the process described above graphically.
Referring now to Figure 2, reference numeral 10 indicates the formed product as it emerges from the extruder, the product being at this stage in the form of an endless slab which is rectangular in cross-section and has a thickness of about 5 cm. The formed product is fed into a bath of setting solution, so that the setting solution comes into contact with the outside surfaces thereof.
The letters A to J indicate various stages as the formed product 10 passes through the bath. First, the setting solution is injected into the formed product 10 by means of a ganged set of needles. Reference numeral 12 indicates one of these needles, the needles being spaced across the width of the slab of formed product, preferably in a diagonally extending line.
At A the needle 12 has just been inserted into the formed product and is moving towards the bottom of the slab of formed product. At B the needle has just commenced its upward
movement, as it is being withdrawn from the formed product. At C the needle has been withdrawn partly, and at D it has been withdrawn fully. While the needle is in the formed product, setting solution is injected under pressure into the product via the needle. To avoid having to stop and start movement of the slab of formed product, the ganged needles can be made to move forward along with the product while they are inserted in the product and, once they have been withdrawn upon reaching the point D, they can then be moved back again to the starting position, where they are then re-inserted into the product. This may be achieved by having the ganged needles mounted on a carriage which can move backwards and forwards in the direction of travel of the slab.
At E the hole left by the needle is starting to close up and the liquid setting solution has dispersed into the product to the maximum distance to which it will disperse from the hole without the assistance of vibration. If left in this condition, setting of the binder would normally take in the order of 24 hours.
At F setting of the binder in close proximity to the hole left by the needle is starting to take place. From G through to J the food product is subjected to sonic/ultrasonic vibration, reference numeral 14 indicating a sonic/ultrasonic transducer whereby the required sonic/ultrasonic energy is generated. The sonic/ultrasonic energy emanating from the transducer 14 is propagated through the setting solution of the bath into the product. This vibratory energy considerably increases the distance to which the setting solution disperses through the volume of the food product, and also considerably speeds up the time required for setting of the binder to take place. At J the food product is ready for slicing.
To ensure that the food product is subjected to the sonic/ultrasonic vibration throughout its cross-section, a plurality of transducers 14 may be provided, these being spaced across the
width of the bath. Where required, to ensure an even distribution of sonic/ultrasonic energy, adjacent transducers may overlap with one another, through being staggered in the direction of travel of the slab.
The following are examples of binding mixtures that have been found to give good results.
Binding mixture A:
INGREDIENT % BY WEIGHT Sodium alginate 80.00 Dextrose 1 5.00 Salt 5.00 Total 100.00
Usage: sprinkle
Amount: 1 part binder to 99 parts meat, by weight.
Binding mixture B:
INGREDIENT % BY WEIGHT
Sodium alginate 35.00
Dextrose 6.00
Carrageenin 6.00
Mash potato powder 53.00
Total 100.00
Usage: sprinkle
Amount: 2 parts binder to 98 parts meat, by weight.
Binding mixture C:
INGREDIENT % BY WEIGHT
Sodium alginate 25.00
Dextrose 4.00 Gum Arabic 1 .00
Sorbitol 1 .00
Carboxy methyl cellulose 1 .00
Potato starch 68.00
Total 100.00
Usage: dissolve and mix
Amount: 3 parts binder to 10 parts water and 87 parts meat, by weight. or
Usage: sprinkle Amount: 3 parts binder to 97 parts meat, by weight.
Binding mixture D:
INGREDIENT % BY WEIGHT
Potato starch 35.00
Soya isolate 25.00 Sodium alginate 20.00
Sorbitol 5.00
Carboxy methyl cellulose 5.00
Whole anti-coagulated blood 5.00
Xanthan gum 2.50 Dextrose 2.50
Total 100.00
Usage: dissolve and mix
Amount: 4 parts binder to 16 parts water and 80 parts meat, by weight.
It is to be understood that many variations are possible, and the choice of ingredients would be determined by the desired sensory and other properties of the final product and by legislatory requirements. These variations could include ingredients such as the following:
Anti-oxidants (e.g. Vitamin E) Preservatives (e.g. sulphur dioxide)
Colour stabilisers (e.g. ascorbic acid) Curing agents (e.g. sodium nitrite) Seasoning
The alginate component may consist of a single alginate (e.g. sodium alginate, potassium alginate, calcium alginate, etc.), a blend of these, or a blend of alginate(s) and pectin and/or other hydrocolloids.
If the binding mixture is added by sprinkling, a small amount of water may be sprayed onto the mixture during mixing, to assist with absorption.
The following are examples of setting solutions that have been found to give good results. Variations are possible, and would be determined by the desired sensory and other properties of the final product, and by legislatory requirements.
Setting solution A:
INGREDIENT % BY WEIGHT
Calcium chloride dihydrate 0.25
Lactic acid powder 2.60
Calcium lactate powder 3.60
Salt 3.55
Water at 3°C 90.00
Total 100.00
Setting solution B:
INGREDIENT % BY WEIGHT
Calcium acetate monohydrate 0.40
Calcium carbonate 3.20
Glucono delta lactone (GDL) 5.00
Salt 1 .40
Water at 3°C 90.00
Total 100.00
Setting solution C:
INGREDIENT % BY WEIGHT
Calcium acetate monohydrate 0.40
Calcium sulphate dihydrate 2.00
Lactic acid powder 1 .20
Salt 3.40
Water at 3°C 93.00
Total 100.00
Setting solution D:
INGREDIENT % BY WEIGHT Calcium chloride 0.15
Calcium acetate 0.20
Glucono delta lactone (GDL) 3.00
Calcium lactate powder 3.00
Salt 3.65 Water at 3°C 90.00
Total 100.00
The following is an example of a process using the binding mixture C and the setting solution A. The following ingredients were used:
INGREDIENT % BY WEIGHT
Meat 87.00
Binder (Example C) 3.00
Water 10.00
Total 100.00
Water is poured into a high speed mixer. The binding mixture is then added slowly whilst mixing well, ensuring that the binding mixture is completely dissolved and a gel has formed. The meat is then put into a massager or slow mixer, and the gel added slowly, mixing well until uniformly dispersed. Care should be taken not to over-mix. The mixer must not damage the meat, but only blend the gel into and around the meat. The mixture is then placed into a filler or extruder.
All the dry ingredients of the setting solution are added to water at 3°C to 5 °C whilst mixing, ensuring that all granules have dissolved. The setting solution is then poured into the bath referred to above.
FOOD PRODUCTS INCORPORATING FRUIT, VEGETABLES, CEREALS, AND/OR NUTS:
The method of the invention may also be applied to fruit, e.g. banana, strawberry, apple, and so on; to vegetables, e.g. onion, tomato, paprika, and so on; to cereals; and to nuts.
Any of the binding mixtures A, B, C, or D and any of the setting solutions A, B, C, or D above may be used. When the binding mixture D is used, the whole anti-coagulated blood should, however, be replaced by potato starch or another suitable filler. After processing, the product may be dried. To this end the product may be sliced into thin slices, or alternatively it may be extruded into a thin sheet. Because of the presence of the binder, natural juices in the fruit or vegetable, particularly in a product such as tomato which contains juice of a watery consistency, will be held captive, thus ensuring that the natural flavours and nutrients in the product are retained during the drying process.
Because it is possible to finely mince or otherwise divide the fruit or vegetable, there is much more intimate contact between any anti-oxidant that is used and the fruit or vegetable. This makes it possible to use a less harsh anti-oxidant such as, for example, vitamin E instead of products such as sodium metabisulphite.
The food pieces (meat, fruit, vegetable, or other food) can be raw or in a partly or fully cooked state when admixing the binder. Blends of raw and/or cooked ingredients can be mixed and extruded. Examples are snack foods comprising a blend of a vegetable and meat (e.g. potato and beef); meat and fruit (e.g. beef and apricot); a vegetable and fruit (e.g. potato and banana); and nuts, vegetable, and fruit (e.g. nuts, potato, and banana).