Love me tender

06 February, 2009

Technology in the meat sector moves on at a great pace. Alyson Magee looks at how technology is developing across the production and processing sectors, with tender meat high on the agenda

“There is great interest in quality in Britain,” says Professor Jeff Wood. “It’s difficult for us to compete as a nation on the cost of production, so quality is something we should be focusing on. Consumers have shown they are willing to pay for higher quality.”

Professor Wood heads up the Farm Animal Science division at Bristol University, home to the BPEX Pork Chain Unit and one of a number of sites commissioned by BPEX and other meat bodies in the UK to undertake projects aimed at raising the bar in quality terms and/or lowering costs of production. Technical work to improve meat quality begins on the farm, with feed and growth rates the focus of a number of current research projects looking at tenderness, boar taint, marbling and nutritional values.

One such project, a collaborative effort with the University of Leeds, involves the impact of growth rates on the tenderness or converse toughness of meat. “Tenderness is the most important determinant of quality and also the most variable,” says Professor Wood. “If industry could consistently produce tender meat, it would help sales.”

Results of the project run contrary to the prevailing idea of a link between slow-growing production and quality. In fact, pigs between the weights of 40 and 100kg that are growing faster than 600g per day are more likely to produce tender meat than their slower-growing counterparts. The principle applies to both poultry and beef as well, says Professor Wood. “It flies in the face of what people believe; if you produce poultry more extensively, it results in better quality,” he says.

US research also backs the findings at Bristol University, with a correlation identified between the growth rate and tenderness at the intensive feed-lots in the US. “It is to do with the muscle proteins,” says Professor Wood. “If protein is formed quicker through faster growth, there is also faster degradation; the breakdown of protein happening after slaughter to tenderise meat.”

Boar taint is an issue particular to the UK and Ireland, which are among the few countries where male pigs are not castrated. Other European countries believe good quality can only be achieved through castration, as pork from un-castrated pigs is contaminated with an odour and taste.

Two naturally occurring compounds – androstenone and skatole – accumulate in the meat of un-castrated pigs, causing the problem and occasionally resulting in an unpleasant odour detectable during the cooking of pork products. Skatole is found in the digestive tracts of all pigs, but whereas castrated and female pigs can metabolise excess concentrations of skatole, for un-castrated pigs, this natural expulsion from the body is slowed down by the actions of their reproductive organs. Researchers at Bristol University have found that introducing chicory into pigs’ diets can reduce the presence of skatole in the gut and therefore in the resultant pork. High levels of inulin in the chicory, which is best added to pigs’ diets towards the end of their feeding period, helps remove skatole residues.

A further unexpected conclusion from the research was greater levels of skatole and androstenone in faster-growing pigs. The assumption that the compounds would accumulate to a greater degree in slow-growing pigs was overturned when older animals were found to have lower boar taint.

“Nutritional values are of considerable interest to consumers,” says Professor Wood. “Meat can been seen as too high in saturated fats, and there is an interest in increasing the level of unsaturated fats.”

Linseed can be added to feed to increase the presence of Omega 3 ‘good’ fats in meat, although exceeding an optimum balance of the ingredient would result in oxidisation and affect the flavour of meat. Meanwhile, Wood’s colleague Dr Ian Richardson has been involved in a Defra-sponsored project, finding superior nutritional attributes in beef from a number of traditional breeds grazing on biodiverse pastures.

Conducted in conjunction with Aberystwyth University and the Grassland Research Station at North Wyke in Devon, the project studied meat from traditional breeds – including Longhorns, Belted Galloways, Beef Shorthorns and Herefords – grazing on pastures as a conservation measure.

Not as selective as modern commercial breeds in their grazing behaviour, the traditional breeds sampled across 50-60 species growing on the pastures, producing meat with a healthy fat composition and antioxidants keeping it bright red for longer, possibly as a result of the diverse diet. “Dry-ageing meat from these animals, which traditional butchers do instead of electrical stimulation, resulted in more tender and juicy steaks than when the meat was aged in vacuum bags,” says Dr Richardson.

Marbling, the fat within the structure of muscles, is viewed as a vital factor in quality, taste and juiciness in many countries. Research at Bristol has focused on achieving the optimum diet for producing beef with good marbling.

“The type of diet influences marbling,” says Professor Wood. “If you have a fattening diet, with a low concentration of protein at the end, marbling increases, although the trick is trying to increase marbling without increasing general fat.”

The marbling benefit may persuade more producers to change the diet of their animals, he says. And a further knock-on effect from a lower-protein diet is lower nitrogen emissions, helping industry meet environmental targets.

 

PROCESSING

Livestock can be reared to the best standards in the book, but if animals become stressed pre-slaughter or carcases are badly handled immediately afterwards, meat quality plummets.

Projects EBLEX has recently worked on with Bristol University include the prevention of dark-cutting beef as a result of stress before culling. “If bulls are stressed in the 48 hours before slaughter, it affects the meat,” says Dr Phil Hadley, SW regional manager for EBLEX. “They tend to fight, particularly when lots of bulls from different groups are put together and a hierarchy battle takes over.”

As a result of the project, EBLEX has just published new guidelines aimed at reducing dark-cutting beef, claiming English bull beef producers could boost their collective returns by an annual £2.3m via improvements in quality. Around a tenth of young bull production is affected by dark-cutting, according to EBLEX, reducing carcase values by as much as 35p/kg or £115/animal for an average-weight young bull. EBLEX recommends management of bulls in stable social groups, as well as further measures, such as keeping transportation to a minimum.

Technology, meanwhile, is playing an increasing role in the analysis of carcases post-slaughter to determine quality and ensure clients’ specifications are met. Bristol University is involved in a number of joint projects with the Scottish Agricultural College, aimed at developing methods to predict carcase composition and meat-eating quality.

One such project involves the use of a CT scanner to analyse complete carcases of sheep and pigs, and smaller portions of beef, with whole cattle too big for the machine. “X-rays from the machine are absorbed to different degrees by the different tissues – meat, fat and bone – due to their densities,” says Bristol University’s Dr Richardson. “It can scan animals alive and dead and, once the machine is calibrated to get a fit between scan data and actual composition derived from carcase dissection, the scanner can be used to predict the composition of total meat, fat and bone in the carcase. It’s a really accurate prediction of the carcase composition, and there are many other things it may be able to tell such as the eating quality and fat composition.”

The research team at Bristol is also looking into more effective monitoring of electrical stimulation to predict texture and improve quality by, for example, reducing cold shortening. “Not enough monitoring of electrical stimulation is carried out and over-stimulation can cause damage, resulting in toughening and excess drip,” says Dr Richardson. “You have to get the rate of pH and temperature right and hit the best window for eating quality.” Ageing for 21 days on top of stimulation boosts tenderness further.

Both EBLEX and BPEX have sponsored research on near infrared spectroscopy (NIR), to measure the tenderness of meat. The Agri-Food and Biosciences Institute in Northern Ireland is also involved in its development for the UK industry.

Animals are quartered at the 10th rib, with the machine taking readings from the surface of the meat to predict tenderness. “With a calibrated instrument, it may be possible to tell the exact tenderness and divide your stock into batches, for example best, standard, processing meat and so on,” says Dr Richardson.

The technology was demonstrated at QMS’ Research and Development conference held in Perth last month (January), with Dr Richardson attending as a speaker. Samples of beef and lamb were tested using the technology, following on from pilot trials on Scotch Beef in 2008. QMS chairman Donald Biggar highlighted the opportunity of guaranteeing tenderness on-pack, citing the example of 65% premiums achieved for beef labelled as aged.

“In the US, it has been used for four to five years, producing some interesting results,” says Dr Hadley. “In the UK, it’s up to industry to take it further. For premium ranges, there would be a guarantee of tenderness.” While hanging helps tenderness, it will not turn around very tough meat, he adds. Thus, NIR is “a good tool to weed out excessively tough carcases”.

Another US-developed initiative, being tested in the UK, is a more rapid instrumental measurement of tenderness. A steak is lifted off the top loin as the carcase is quartered, then cooked and measured for tenderness, enabling classification of the carcase. Thus, processors can “within 20 minutes, go back and label the carcase tender or tough to decide whether it goes into its best line or not”, says Dr Richardson.

 

FURTHER PROCESSING

Technical challenges continue beyond the rearing and optimum cull conditions for livestock, with developments at the meat processing end ranging from new butchery tricks, to maximise carcase potential, to the impact of maturation and ingredients on meat quality.

Although ageing is more readily associated with beef, research at Bristol University has highlighted its positive impact on tenderness in pork. Storing pork at 1˚C, and increasing ageing from a few days to 7-10 days results in a better product from both species. The project has also revealed notable results from ageing meat from rare and traditional breeds, such as the Gloucester Old Spot, which rated particularly high in taste panel tests.

Bristol University has been looking into the use of marinades and basting solutions post-slaughter to increase water retention of the muscle and, thereby, juiciness. Using a marinade can change the characteristics of the muscle, boosting water retention within the protein structure through an electrostatic charge. Ingredients in the application include salts, compounds to alter acidity from a more typical 5.5 to an optimum pH of 5.7/5.8, and an optional flavouring agent.

“Use of marinades is very common in the US,” says Professor Wood. “Almost 100% of pork there is enhanced. The UK industry has been loath to use them because of the bad press here about water in meat and poultry, but it will be used more. All the supermarkets are doing it because taste tests with consumers have been very promising.”

Meanwhile, EBLEX has just published a new booklet for caterers, New Speciality Steak Range, aimed at maximising use of the forequarter and offering more affordable steaks. This offers guidance on removing the feather blade/flat iron muscle, which is hard to get out, but produces tender steaks. “Mince is such a strong seller right now, but forequarter is typically too good for mince,” says EBLEX’s Dr Hadley. “You can get six good steaks from each side.”

 

INGREDIENTS CHALLENGE

The meat industry is facing ever greater challenges when it comes to ingredients, with concerns over salt, fat, sugar, E-numbers and allergens all thrown into the mix. “Over the last decade, the rise in consumers’ disposable income and concerns over health have created a different environment for food technologists,” says Richard Eden of London-based ingredients supplier Fibrisol. “With the growth of consumer incomes, the multiple retailers have generally moved towards premium-range products,” says Eden. “This has resulted in clean-label drives, with ingredients required to be ‘kitchen cupboard’ or ‘health benefit’ category.”

However, the recession has thrown up new concerns. “Consumers are now looking at cost, which has resulted in the expansion of economy ranges and the acceptance of the need for ingredients which had become less popular,” he says. “Recession has reduced the drive for ultra-clean labelling but the goal posts have moved irrevocably over the past decade.

Salt reduction is a complex issue, says Eden, with solutions including low-sodium salts based on potassium chloride rather than sodium chloride. However, potassium chloride can result in a bitter taste, requiring masking through the addition of herbs or flavours to the mix. Further, commercial sodium/potassium chloride blends can cost up to 10 times the price of regular salt, says Eden.

More general solutions include cutting overall salt inclusion, although shelf-life and food safety issues can then arise. “The biggest impact has been in the reduction of nitrite levels in cured meats and the general removal of nitrates, except in traditional products. This has resulted in a significant growth in the production of dry cures and Wiltshire-style cures,” adds Eden.

Manufacturers are coming under increasing pressure to reduce the presence of E-numbers in foods, due to their negative public image. “E-numbers, introduced to clarify Europe-wide labelling and identify the ingredient as safe, are often regarded with suspicion,” says Eden. “Many useful ingredients have been removed from meat products just to reduce the ‘E count’. This has required a lot of lateral thinking from food technologists.”

Among available solutions to replace phosphate binders are high- and low-amylose starch blends, meat proteins and speciality vegetable fibres. How-ever, with phosphates also aiding in the retention of natural succulence, they are “very difficult to side-step”, says Eden, who adds: “Food technology has always been a challenge but, under the new requirements and financial austerity, the demands are greater than ever.”

 





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