GB2350119A - Rubber compounds for use in food wrappings - Google Patents

Abstract

A rubber compound suitable for use in a netting or other wrapping for food, especially meat, exhibits an alteration in its elastic properties following exposure to heat. The loss in elastic memory may result in an overall increase in the length of the netting or other wrapping by 15% to 35%. The rubber compound may contain an amount of antioxidant which is less than that found in standard rubber compounds, e.g. 20% less. The use of the rubber compound in the netting or other wrapping results in the wrapped product not being bound too tightly during and after cooking.

Description

2350119 1 1 TWO PHASE COMPOUM 2 3 This invention relates to an improved

food netting and 4 wrapping product. More specifically, this product relates 5 to an elastic netting or thread wrapping for meat or food 6 products, which exhibits unique characteristics. 7 8 Elastic meat netting was developed around the middle of 9 the 1950's where it was manufactured with cotton on the 10 warp chains and cotton covered rubber thread on the weft 11 chains. 12 13 It was originally used for wrapping the final product 14 during the production of salami. As the meat was not 15 cooked or reheated after wrapping in the netting product, 16 the effect of high temperatures on the netting was not 17 considered at that time. 18 19 In the 1960 Is elastic netting began to be used in the 20 United Kingdom, primarily for the wrapping of beef joints 21 prior to roasting. At that time the netting was 22 manufactured and marketed in two alternative embodiments; 23 the first netting being suitable for withstanding oven 2 1 roasting temperatures of up to 250'C and a second which 2 was suitable for use during the boiling of meat at

3 temperatures of around 1OCC. 4 5 The difference between these two types of product was 6 entirely a result of the amount of cotton wrapping applied 7 to the rubber thread, with the roasting embodiment having 8 a greater amount of cotton covering than that applied to 9 the rubber of the embodiment used for boiling. 10 11 Additional cotton wrapping was applied to the rubber to be 12 used at higher temperatures as it afforded a greater 13 degree of protection to the rubber, thus preventing it 14 from being degraded by the heat. 15 16 One important part of rubber technology is that of 17 ensuring that rubber does not loose its elasticity when 18 exposed to high temperatures. For example, it is 19 essential that the rubber which is used in manufacture 20 does not suffer a loss of elasticity when exposed to high 21 temperatures. 22 23 The maintenance of the elasticity of a rubber compound 24 following the exposure of it to high temperatures has been 25 identified as a desirable characteristic adopted by the 26 field of elastic meat nettings and wrappings. It is 27 currently believed that it is necessary for the rubber 28 component of the netting or thread wrapping to maintain 29 its elastic properties on exposure to the high 30 temperatures experienced during the cooking process. 31

3 1 The basis f or this thinking is that when meat cooks it 2 contracts and therefore it is thought that the netting or 3 wrapping encompassing the meat product should also 4 contract in line with the change in shape of the meat product. Thus, the elastic tension exhibited on the meat 6 by the netting will not be reduced during cooking.

7 8 This creates a problem in that after the joint or meat 9 product has been cooked, the netting has a tendency to adhere to the joint and thus whenever the netting is cut 11 from around the joint prior to carving, the netting 12 springs back and splashes droplets of fat on the carver.

13 14 The problem of the netting adhering to the meat has been recognised f or the last ten years with a variety of 16 approaches having been unsuccessful in attempting to 17 overcome these problems.

18 19 Examples of such attempts are the use of a heavier cotton wrapping being applied to the rubber, with the intent that 21 it would prevent the rubber weft from adhering to the meat 22 during cooking. Another unsuccessful approach used the 23 immersion of the netting or wrapping, prior to application 24 on the product and cooking, in a solution which was meant to prevent the build up of exude from the meat adhering to 26 the netting or wrapping.

27 28 It is an object of the present invention to provide a 29 netting or thread material which will be suitable for the wrapping of meat products during cooking, wherein the 31 netting exhibits characteristics such that on exposure to 32 heat the rubber compound loses part of its elastic 33 properties, thus preventing the elastic being too tightly 4 1 adhered to the meat which can lead to spring back 2 retraction and subsequent spray of fat on the carver, when 3 the netting is cut during the serving of the meat product. 4 5 According to the present invention there is provided a 6 rubber compound suitable for use in a netting or wrapping 7 for meat, which exhibits an alteration to its elastic 8 properties following exposure to heat. 9 10 Preferably the rubber compound, loses at least part of its 11 elastic memory following exposure to heat. 12 13 Essentially the rubber will not completely loose its 14 elasticity following exposure to heat.

is 16 Preferably the rubber compound exerts varying degrees of 17 elastic tension on a meat joint around which it is wrapped 18 in response to heating. 19 20 Preferably exposure of the rubber compound to heat results 21 in an overall increase in the length of the net or 22 wrapping by 15% to 35%. 23 24 The invention further provides a rubber compound for use 25 in a netting or wrapping for meat, wherein the composition 26 of said rubber consists of an amount of antioxidant equal 27 or less than 20%, to that found in standard rubber 28 compounds. 29 30 Preferably the amount of antioxidant is preferably between 31 30% and 70% to that found in a standard rubber compound 32 formulation. 33 1 More preferably the amount of antioxidant is preferably 2 between 45% and 55% to that found in a standard rubber 3 compound formulation.

4 A further aspect of the present invention provides a 6 rubber compound wherein an alteration of the elastic 7 properties results when said compound is heated above 8 800C.

9 Preferably the alteration of the elastic properties of the 11 compound occurs when the compound is heated above 1000C.

12 13 Preferably said rubber compound has an average increase in 14 its relaxed length of around 20% when exposed to a cooking is temperature of 1000C for a period of 1 hour.

16 17 Use of a rubber compound as claimed in any of the 18 proceeding claims, for use in the preparation of a meat 19 netting or thread wrapping, for use during the cooking of the meat.

21 22 The invention further provides netting for meat consisting 23 of the rubber compound as described above.

24 Preferably the alteration to the elastic memory of said 26 meat netting occurs on exposure to heat of temperatures of 27 above 80'C.

28 29 More preferably the alteration to the elastic memory of said meat netting occurs on exposure to heat of 31 temperatures of above 1000C.

32 6 1 Preferably the meat netting will not adhere to the meat 2 around which it has been wrapped following the cooking of 3 the meat.

4 Preferably the meat netting will wrap the meat with more 6 elastic tension during the initial stages of cooking, than 7 during the latter stages of cooking, wherein the latter 8 stages are defined as being at any point after the first 9 hour of cooking.

11 Preferably the meat netting or wrapping can be removed 12 from the meat following cooking, with very little elastic 13 recoil or spring back resulting.

14 is Covering Latex Rubber 16 17 Latex rubber threads are always covered under tension, or 18 in an extended state. As a rough indication, 10cm of 19 uncovered latex rubber thread are stretched to 53cm and covered at that tension. After covering, the covered 21 thread is then allowed to relax, assuming a length of 22 approximately 12.5cm.

23 24 A function of the covering is to put the power of the covered latex rubber into the right area of the power 26 curve whenever it is on the meat product. Figure 1 27 illustrates such a power curve and illustrates the 28 relationship between the elongation of the rubber and the 29 "power" of the rubber to recover to its original state.

31 The covering serves to restrict the length to which the 32 rubber can be extended and it also restricts the 33 contraction. If the covered rubber is gently pulled at 7 1 its extended length, it is observed that the outer 2 covering breaks first of all, followed by the inner 3 covering. Once these coverings are broken, the raw latex 4 can be extended much more than before the covering broke.

6 If 12.5cm of covered natural latex rubber is taken and the 7 covering removed, the latex core will measure about 10.4 8 cm and will only come back to its original state during 9 heating. This can be checked by putting the uncovered rubber core into hot water for about 20 minutes where it 11 should revert back to its original length.

12 The relaxation of the elastic tension in the food netting 13 should occur at an appropriate time which is not too late 14 in the cooking process. Ideally, although tension is is required at the initial stages of cooking, the elasticity 16 of the rubber should reduce later in the cooking process 17 such that excessive pressure is not applied to the meat as 18 this can lead to the juices being exuded. This problem 19 occurs particularly in situations where a netted product is cooked in a bag. The exudate envelops the netting, and 21 when the exudate "sets-up" during the cooling stage, this 22 can make the netting difficult to remove. 23 24 Further where the netting is being used to wrap a pork 25 joint as a sufficient pressure must be applied to the 26 joint during the initial stages of cooking. This prevents 27 the formation of gaps or cavities in the meat during 28 cooking. 29 30 On domestically roasted meats and in particular beef (as 31 this is generally solid muscle), the cavity problem 32 associated with the cooking of pork joints does not arise, 33 but what is believed to be the determining factor here is 8 1 that, after the meat has been cooked, the netting should 2 not appear to be slack on the joint, as this could 3 indicate to the consumer that there was excessive 4 shrinkage of the joint wherever the opposite is the case.

6 At present the following chemicals are used to manufacture 7 food grade rubber thread and netting:

8 9 Latex (approximately 85% of total composition) - Potassium Hydroxide 11 - Antioxidant (Sterically altered phenol (1.25%)) 12 - Clay 13 Sulphur 14 - Oleic Acid - Zinc dibenzyl dithlocarbamate (ZBEC) 16 Dipentamethylene thiuram tetrasulphate (DPTT) 17 - Zinc diethyl dithlocarbamate (ZDEC) 18 - Zinc Oxide 19 - Silicone Emulsion (Dimethyl polysiloxane) 21 Through an alteration in the amount of certain components 22 added to the rubber compound, the elastic properties of 23 the rubber can be varied.

24 In a particular example the memory loss properties of a 26 rubber, as described above, can be achieved by reducing by 27 approximately half, the amount of anti-oxidant present in 28 the rubber composition.

29 The formation of the rubber compound using a modified 31 composition allows for a fundamental change in the post- 32 heating properties of the rubber. Such a change will in 33 turn result in changes in the overall performance and 9 1 characteristics of the rubber at the post heating stage.

2 Examples of such benefits which may result is that the 3 meat netting should no longer ping back and cause 4 splatter.

6 Netting products into which the rubber is incorporated 7 will exhibit specific advantages in having two phases 8 which exhibit different degrees of elasticity. The initial 9 level of elasticity of the product will aid the wrapping of the netting or thread wrap around the meat and will 11 provide considerable support to the joint during the 12 initial stages of cooking. The post heating elastic 13 properties will ideally prevent excessive elastic tension 14 being exerted on the meat during the latter stages of cooking which can lead to excess juices being exuded from 16 the meat and also the adherence of the netting to the 17 joint, which in turn may lead to the problem of 18 splattering as discussed above.

19 Experimentation designed to look at both the practical 21 aspects functional characteristics and efficiency of the 22 product detailed below:

23 24 Experiment 1 26 The characteristics of memory loss rubber (MLR) were 27 compared to that of natural latex rubber (NLR) 28 29 In each case a 10cm LF Loop was tied (20cm circumference) Beef joints with an approximate circumference of 30cm were 31 used for testing purposes. The loops were wrapped around 32 the joints prior to cooking. The looped meat joints were 33 then subjected to one of two cooking methods, these were 1 either boiling (where the looped meat joints were placed 2 into boiling water and cooked for two hours), or 3 alternatively roasting (where the looped meat joint was 4 wrapped in foil and cooked at 1800C for 2 hours) 5 6 Measurements taken after 1 hour and 2 hours cooking were 7 taken from the joints when they were in a relaxed ',lay 8 flat, state. These results are shown on Table 2. 9 10 11 12 13 14 is Table 2 % Increase in Relaxed Length(of covered rubber) Cooking 1 hour 2 hours Temperature Standard MLR Standard MLR 1000C A 7.2 22.6 15.4 31.0 B 6.7 18.3 is 28.5 c 6.9 19.0 16.7 31.0 D 7.1 20.5 17 29.3 AVERAGE 7.0 20.0 16.0 30.0 1800c A 11.9 29.2 24.1 28.9 B 11.6 28.6 26.0 31.2 c 11.4 27.4 25.8 31.3 D 12.9 26.9 1 24.2 1 28.4 JAVERAGE 12. 0_ 28.0 25.0 30.0 16 17 The results illustrate that both MLR and standard NLR lose 18 the memory they are going to lose during the f irst hour of 19 cooking at 1800C. For industrially cooked meats, particularly pork, it is essential that the meat is held 21 together during the initial stages of the cooking process.

22 with sufficient pressure to enable the muscles to bind 11 1 together, to prevent cavity formation, as previously 2 described. The tests have shown that the MLR product has 3 the optimum memory loss characteristics for a netting 4 product, such that these criteria can be met. Any further loss of elasticity of the netting could lead to cavity 6 production due to the joint not being held together for a 7 long enough period of time during the initial stages of 8 cooking. 9 10 Figure 1 is an illustration of how the tension of both the 11 memory loss rubber as normal latex rubber react when 12 exposed to heat, over a period of time. 13 14 Experiment 2 is 16 This experiment consists of three trials which aimed to 17 further define the properties and associated benefits of 18 the memory loss rubber netting, when compared to a net 19 currently used by a supermarket.

21 Medium topside joints which were purchased in a 22 supermarket (these being of similar weights and 23 dimensions) The supplied net was removed from some of 24 the joints and replaced with the MLR net. The joints were then wrapped in tinfoil and cooked in the oven following 26 cooking recommendations on the packaging. Some were 27 cooked open in the oven and basted every 20 minutes.

28 29 Three tests were carried out and are detailed below.

31 Trial 1 32 12 1 This trial set out to evaluate whether the MLR netting 2 had:

3 4 1 an acceptably low level of spring back when jointing prior to roasting 6 7 2. does product have acceptable stripability following 8 roasting; and also 9 3. to compare the cooked weight and highlight any yield 11 advantages which may be evident over joints which are 12 cooked using the MLR netting.

13 14 One leg roll was strung and three were netted through is 160mm mini tubes in the following nets 16 1. Ultrapeel 90 LF Super Roast Blue MLR 17 2. Ultrapeel 104 LF Super Roast Blue MLR 18 3. Ultrapeel 160 Super Roast 19 1. Spring Back 21 22 UP 90 LF Super Roast Blue MLR performed very well with no 23 noticeable spring back in any of the three cut joints.

24 UP 104 LF Super Roast Blue MLR performed very poorly. The spring back on all three joints was extreme with cigar 26 banding on two of three. (Based on the spring back these 27 joints were excluded from the subsequent roasting trial) 28 29 UP 160 Super Roast performed to an acceptable level with a 30 small amount of spring back.

31 13 1 In summary, the UP 90 LF MLR netting performed extremely

2 well with no noticeable spring back and was fully 3 acceptable.

4 The joints netted with the UP 90 LF MLR were then placed 6 in an open tray and roasted along with the strung 3oints.

7 The next test was the stripability of the net and string.

8 The method of removing the net and string was a sharp 6n 9 boning knife.

11 2. Stripability 12 13 UP 90 LF Super Roast Blue MLR performed very well, the 14 netting was sitting on top of the meat with no noticeable is embedding of the net into the surface of the meat. The 16 cutting motion of the knife did not cause any noticeable 17 splashing. The stripability of this net was acceptable.

18 3. Cooked Weight 19 The pre-cooked weights were compared against the roasted 21 weights. The UP 90 LF MLR netting was shown to have a 22 weight loss of 35%, while the Ultrapeel 160 Super Roast 23 had a higher weight loss of 38%.

24 In summary, UP 90 LF Super Roast Blue MLR resulted in the

26 best cooking result with a reduction of 9% cooking loss.

27 28 In addition to the above tests, the following data on the 29 netting expansion was also recorded during cooking.

31 UP 90 LF SR Blue MLR UP 160 SR 32 Net Expansion 180mm>25Omm 160mm>195mm 33 % Expansion 25% 17.9% 14 1 2 The trial results with UP 90 LF Super Roast Blue were a 3 resounding success with an improvement in cooking yield 4 against their existing net along with easier stripability.

An unexpected bonus was the lack of spring back.

6 7 Trial 2 8 9 This trial tested the three netting products of Trial 1 for the roasting of a pork joint which was obtained from 11 a supermarket. Again the three criteria used for 12 assessment in Trial 1 were used to evaluate whether the 13 MLR had:

14 1. an acceptably low level of spring back when jointing 16 prior to roasting 17 18 2. acceptable stripability with our MLR nets following 19 roasting; and also 21 3. to compare the cooked weight and highlight any yield 22 advantages which may be.

23 24 This trial however used pork which had been obtained from 25 a supermarket.

26 27 One leg roll was strung and two were netted through 160mm 28 mini tube in the following nets:

29 1. Ultrapeel 90 LF Super Roast Blue MLR 31 2. Ultrapeel 104 LF Super Roast Blue MLR 32 3. String 33 is 1 The netted and strung legs were tempered for 48 hours at 2 20C and 48 hours later were tested with respect to the 3 above criteria, with the results as follows; 4 5 1. Spring Back 6 7 UP 90 LF Super Roast Blue MLR performed very well with no 8 noticeable spring back in any of the three cut joints. 9 UP 104 LF Super Roast Blue MLR performed very poorly, the 10 spring back on all "three joints was extreme with cigar 11 banding on two out of three. (Based on the Spring Back 12 these joints were excluded from the roasting trial) 13 14 The strung roast performed to an acceptable level with a 15 small amount of spring back. 16 17 Both JS and Grampian confirmed UP 90 LF Super Roast Blue 18 MLR performed extremely well with no noticeable spring 19 back and was fully acceptable. 20 21 The netted joints were then placed in an open tray and 22 roasted along with the strung joints. The next test was 23 the stripability of the net and string. The method of 24 removing the net and string was a sharp 6u boning knife. 25 26 2. Stripability 27 28 UP 90 LF Super Roast Blue MLR performed very well, the 29 netting was sitting on top of the meat with no noticeable 30 embedding of the net into the surf ace of the meat or 31 crackling. Both JS and Grampian confirmed the 32 stripability of this net was acceptable. 33 16 1 UP 160 Super Roast resulted in an unacceptable level of 2 stripability, the net was embedded into the crackling and 3 had to be tugged clear, there was an unacceptable level of 4 splashing upon cutting.

6 String resulted in the string embedding into the 7 crackling, it was very difficult to remove with bits of 8 string coming away.

9 Both JS and Grampian confirmed UP 90 LF Super Roast Blue MLR was fully acceptable. It performed very well and 11 compared favourably against both conventional net and 12 string.

13 14 3. Cooked Weight 16 The pre-cooked weights were compared against the roasted 17 weights, with the cooking losses being as follows:

18 19 UP 90 LF SR MLR UP 160 SR STRING Weight Loss 35% 38% 43% 21 22 UP 90 LF Super Roast Blue MLR resulted in the best cooking 23 result with a reduction of 9% cooking loss compared to 24 string. There were no noticeable differences in succulence.

26 27 In the addition to the above tests, the following data was 28 also recorded on the netting expansion during cooking:

29 UP 90 LF SR Blue MLR UP 160 SR 31 Net Expansion 180mm>25Omm 160>195mm 32 % Expansion 28% 17.9% 33 17 1 The trial results with UP 90 LF Super Roast Blue were a 2 resounding success on the pork leg with an improvement in 3 cooking yield against their existing string along with 4 easier stripability. An unexpected bonus was the lack of spring back.

6 7 Table 3 shows the cooking losses that have been 8 consistently obtained in tests on roasting beef where 9 standard netting, string and memory loss rubber have been used. It can be seen that on comparison of standard 11 netting against string, there is a weight gain of 13% 12 whilst with Memory Loss Rubber the gain is almost 23%, and 13 against standard net the gain is almost 9%.

14 15 Table 3: Cooking loses from meats wrapped with different 16 nettings 17 MEMORY LOSS STANDARD STRING RUBBER NETTING Weight Loss % 35% 38% 43% % gain on (38-35) standard net 35 X 100 = 8. 6% % gain on (43-35) (4338) string 35 x 100 = 22.8% 38 x 100 = 13.1% 18 19 The reduction in weight loss comes from the reduction in the losses of juices during cooking, thus producing a more 21 succulent joint.

22 23 Trial 3 24 This trial looked specifically at the characteristics of the netting and its ability to hold a pork joint together 18 1 initially during cooking such that cavities would not form 2 during cooking.

3 4 Essentially this test was designed to establish whether the properties of the MLR rubber, which had already been 6 established from Trials 1 and 2 resulted in the rubber not 7 being able to exert adequate tension on the joint 8 initially during the cooking process to hold the joint 9 together with sufficient pressure to stop cavities forming. A further aspect of this trial looked to 11 evaluate the stripability of the MLR net after roasting.

12 13 One rolled joint was netted with ND 985 U/Peel 140 Super 14 Roast MLR 85mm.

is The joint was cooked according to the recommendations on 16 the packaging - which was 4 hours at 1900C. The joint was 17 open roasted with one half of the top joint sprinkled with 18 flour.

19 The pre-cooked weight was compared against the roasted 21 weight and the weight loss was found to be 36%.

22 23 The net performed very well with respect to holding the 24 joint together. There was no noticeable embedding of the net into the surface of the meat or crackling.

26 27 The net was easy to remove with little or no splattering 28 of fat or gravy. There was no difference in the 29 stripability between the half of meat covered with flour and the other half. Although it was apparent that in a 31 small part of the net the rubber seemed to have diminished 32 but there was no significance to the area in which this 33 happened.

19 1 2 Experiment 3 3 4 This experiment consisted of a series of stripability trials relating specifically to how easily the MLR netting 6 could be removed from the joint following cooking of the 7 meat.

8 9 All netted samples were provided on the morning of the 10 test and the trials were completed on the same day.

11 12 12 pre-netted 'standard, joints and 12 pre-netted 13 'special, joints were provided and all samples were 14 immediately weighed (in pack) and coded with random 3 digit numbers.

16 17 All joints were then removed from the package and re18 weighed and all of these results are recorded in columns 19 (A) and (B) as shown on Table 4.

21 12 of the joints were then re-netted utilising the memory 22 loss rubber net an all joints were re-weighed (Table 4, 23 column C).

24 All meats were then cooked in a Hobart Combination oven in 26 2 batches as follows:

27 28 Batch A 29 6 standard net joints open cooked, regular basting 6 special net joints 1 hour at 2000C/40 minutes at 31 1600C 32 Batch B 33 6 standard net joints cooked in foil 1 6 special net joints 1 hour at 2000C/1 hour at 1600C 2 3 The results are shown in Table 4.

4 All samples were re-weighed (column D) on exiting the oven (minus meat juices) and allowed to stand for 5 6 minutes before the nets were stripped and the remaining 7 meat re-weighed (column E).

8 9 Comments on stripability of standard net were that:

11 Open Cooked Meat Difficult to come off 12 Slight Sticking 13 A lot of surface fat, comes off 14 well though is Difficult to remove, bits of fat 16 sticking to net 17 18 Comments made on stripability of special net 19 Open Cooked Meat Came off easily, surface fat 21 remaining on meat 22 No problems in removing net 23 24 Foil Cooked Once the end of the net is released, the remaining slips off 26 easily 27 28 A slight improvement in the stripability of the special 29 net in comparison to the standard net was seen. The results indicate a 5% better retention of meat in the 31 special net after stripping which has the benefit of 32 maximising the yield of meat.

33 Table 4 21

SAMPLE CODE (A) (B) (C) (D) (E) (F) (G) (H) NO INITIAL WEIGHT OF REWIEGH COOKED COOKED COOKED COOKED COOKED PACK MEAT WITH WEIGHT MEAT MEAT + MEAT + MEAT - WEIGHT JOINT SPECIAL WITH NET WITHOUT NET/ WT NET/ WT NET (kg) (kg) NET (kg) (kg) NET (kg) OF MEAT OF MEAT /COOKED JOINT JOINT % WT MEAT NET % Standard Net, Foil Cooked 615 0.921 0.901 0.555.0546 61.5 60.5 98.4 Standard Net, Foil Cooked 615 0.844 0.834 0.504 0.496 60.4 59.5 98.4 Standard Net, Foil Cooked 615 0.927 0.914 0.554 0.543 60.6 59.4 98.0 Standard Net, Foil Cooked 297 0.925 0.915 0.599 0.591 65.5 64.6 98.6 Standard Net, Foil Cooked 297 0.985 0.935 0.526 0.518 56.2 55.4 98.6 Standard Net, Foil Cooked 297 0.862 0.848 0.558 0.550 85.8 64.9 98.6 Standard Net, Open Cooked 139 0.934 0.919 0.552 0.548 60.0 59.6 99.3 Standard Net, Open Cooked 139 0.812 0.904 0.542 0.536 59.9 59.3 98.9 Standard Net, Open Cooked 139 0.815 0.788 0.448 0.441 57.0 56.0 98.4 Standard Net, Open Cooked 520 0.902 0.890 0.525 0.520 58.9 58.4 99.0 Standard Net, Open Cooked 520 0.927 0.892 0.542 0.538 60.7 60.3 99.3 Standard Net, Open Cooked 520 0.940 0.928 0.570 0.520 61.4 66.8 91.2 Special Net, Foil Cooked 364 0.997 0.977 0.972 0.612 0.603 62.9 62.0 98.5 Special Net, Foil Cooked 364 0.924 0.911 0.906 0.554 0.545 61.1 60.1 98.4 Special Net, Foil Cooked 364 0.902 0.892 0.884 0.545 0.636 61.6 60.6 98.4 Special Net, Foil Cooked 803 0.924 0.904 0.899 0.541 0.533 60.2 59.3 98.5 Special Net, Foil Cooked 803 0.977 0.966 0.961 0.581 0.572 60.5 59.5 98.5 Special Net, Foil Cooked 803 0.929 0.914 0.908 0.548 0.540 60.4 59.5 98.5 Special Net, Open Cooked 746 0.857 0.846 0.839 0.515 0.509 61.4 60.7 98.9 Special Net, Open Cooked 746 0.846 0.829 0.823 0.491 0.486 59.7 59.0 99.0 Special Net, Open Cooked 746 0.847 0.833 0.828 0.477 0.469 57.6 56.6 98.4 Special Net, Open Cooked 293 0.891 0.879 0.873 0.526 0.517 60.0 59.2 98.3 Special Net, Open Cooked 293 0.846 0.823 0.819 0.492 0.485 60.0 59.2 98.6 Special Net, Open Cooked 293 0.976 0.955 0.948 0.589 0.583 62.0 61.5 99.0 22

Claims (16)

1. A rubber compound suitable for use in a netting or wrapping for meat, which exhibits an alteration to its elastic properties following exposure to heat.

2. A rubber compound, as claimed in claim 1 which loses at least part of its elastic memory following exposure to heat.

3. A rubber compound as claimed in claim 1 or 2 which exerts varying degrees of elastic tension on a meat joint in response to heating.

4. A rubber compound, as claimed in any of the proceeding claims wherein the loss in elastic memory results in an overall increase in the length of the net or wrapping by 15-35%.

5. A rubber compound for use in a netting or wrapping for meat, wherein the composition of said rubber consists of an amount of anti-oxidant which is equal or less than 20%, to that found in standard rubber compounds.

6. A rubber compound as claimed in claim 5 wherein the amount of antioxidant is preferably between 30 and 70% to that found in a standard rubber compound formulation.

7. A rubber compound as claimed in claim 5 wherein the amount of antioxidant is preferably between 45 and 55% to that found in a standard rubber compound formulation.

23

8. A rubber compound as claimed in any of the proceeding claims wherein an alteration of the elastic properties results when said compound is heated above 80'C.

9. A rubber compound as claimed in claim 8 wherein preferably the alteration of the elastic properties of the compound occurs when the compound is heated above 1000C.

10. A rubber compound as claimed in claim 8 which has an average increase in its relaxed length of around 20% when exposed to a cooking temperature of 1000C for a period of 1 hour.

11. Use of a rubber compound as claimed in any of the proceeding claims, for use in the preparation of a meat netting or thread wrapping, for use during the cooking of the meat.

12. A meat netting consisting of the rubber compound as claimed in claims 1 to 11.

13. A meat netting as claimed in claim 12 wherein an alteration to the elastic memory occurs on exposure to heat of temperatures of above 800C.

14. A meat netting as claimed in claim 12 wherein preferably an alteration to the elastic memory occurs on exposure to heat of temperatures of above 1000C.

24

15. A meat netting as claimed in claim 11 characterised in that it adheres to a meat joint with more elastic tension during the initial stages of cooking, than during the latter stages of cooking, wherein the latter stages are defined as being at any point after the first hour of cooking.

16. A meat netting as claimed in claim 11 characterised in that the netting or wrapping can be removed from the meat following cooking, with very little elastic recoil or spring back resulting.