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You are here: Agriculture » About Agriculture » Newsletters and Updates » Ag in Focus » Ag in Focus - Spring 2011 » Keeping lamb meat red

Keeping lamb meat red

Lambs on annual pasture

At a glance

Lambs on dry annual pasture

• Consumers reluctant to buy brown meat lower in redness even when the product is still in date.
• Producers can slow meat going brown by lifting vitamin E and iron levels in muscles.
• Fresh grass is high in vitamin E.

New research from DPI is set to help producers make their lamb meat stay red for longer and help boost retail sales.

A recent survey by the Sheep Cooperative Research Centre (Sheep CRC) found that 41 per cent of consumers would not eat meat that appeared brown due to a reduction in redness, even while in date.

As a consequence, retailers often discount meat, so that it is not on display longer than two days.

DPI scientist Eric Ponnampalam said a series of studies carried out in Rutherglen and across southern Victoria looked at ways that producers could improve the shelf life of their lamb and slow its discolouration.

One study looked at the role of iron, antioxidants (vitamin E) and fatty acids in keeping lamb meat red for longer and its findings proved a departure from earlier thinking.

“Previous research had linked fatty acids such as Omega-3 and Omega-6 with maintaining colour and flavour or aroma of meat,” Dr Ponnampalam said.

Instead, vitamin E and iron levels were found to be most influential.

Making on-farm changes

Eric Ponnampalam examining meat colour of first cross and second cross lambs, aged seven to nine months

So, what can farmers do to improve the shelf life of their lamb?

Another study set out to answer this question.

Dr Ponnampalam said researchers compared lambs fed on a senesced (mature) annual pasture and a range of grain pellets (Treatments 2–4) with those fed on lucerne and phalaris mixed perennial pasture (Treatment 1) over a seven-week period.

The grain pellet consisted of 60 per cent lucerne hay, five per cent grass hay and 35 per cent oat grain in Treatment 2.

In Treatments 3 and 4, 10 per cent of the oat grain was replaced by flaxseed and flaxmeal respectively.

During the first two weeks of the study, lambs on annual pastures were given 500g of pellets each day.

This was increased to 700g daily for the remaining five weeks.

“Colour stability of fresh and aged meat was assessed by measuring the change in redness of the meat and the formation of brownness — the ratio of oxymyoglobin and metmyoglobin (oxy/met) in the meat surface,” Dr Ponnampalam said.

The study showed that lambs grazed on perennial pastures consumed much higher levels of vitamin E — about 57.2mg per day — as compared to 8.0–8.3mg/day for those on annual pastures and supplements.

Dr Ponnampalam said it was clear that lambs fed perennial pasture (Treatment 1) had significantly higher levels of vitamin E than those on annual pastures with supplements (Treatment 2–Treatment 4).

Lambs on annual pastures had 3.1–3.6mg, while lambs on perennial pastures had 5.9mg alpha-tocopherol/kg of muscle.

“Sheep are likely to absorb vitamin E in green feed better than any sort of vitamin E supplement,” Dr Ponnampalam said.

“We believe that lambs might need as little as 200–400 grams of lucerne hay daily to increase vitamin E levels.”