Fish Oil and Oxidation Products

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http://www.crop.cri.nz/home/news/releases/1159137244997.jsp

Consumers buying foods with omega-3 may not be getting the good oil

they think they are says Rufus , a lipids scientist with Crop

& Food Research.

He and colleague, Dr Carlene McLean, have studied commercially

available fish oil in New Zealand, that's been manufactured

overseas. They found it contains varying levels of primary and

secondary oxidation products.

" These oxidised products result in variations in the quality of fish

oils and may explain the mixed results in international human

clinical trials investigating omega 3 health benefits " Dr McLean

said.

Recent results from international cellular, animal and human trials

indicate that the oxidised products in fish oils may have potential

carcinogenic and pro-inflammatory actions. These products have the

potential to increase the risk of atherosclerosis and thrombosis and

reduce the potential benefits of omega-3 fatty acids.

Dr says that unfortunately, fish oils containing omega-3

fatty acids are unstable and more vulnerable to oxidation than

vegetable oils or other animal fats. When fish oils come into

contact with oxygen and are exposed to metals, light and heat they

degrade. Oxidation of the oil accelerates after extraction from the

fish and during subsequent storage.

Dr McLean says New Zealand is at the forefront of research providing

solutions for long-term preservation of commercial oil products for

human use. Fish oil producers are working with scientists at Crop &

Food Research to ensure New Zealand-produced oil is of the highest

quality.

" We are using the by-products from the filleting process, which

constitute up to 60% of the fish weight and contain up to 10% oil,

to produce a value-added, high-quality nutraceutical oil, " says Dr

McLean. " As well as looking at ways to improve handling of the raw

material after harvest, we are working with industry to modify their

by-product processing operations, to improve yields and the quality

of oil and protein extracts. "

Dr says, " It is essential to ensure that fish oil in food

products has good levels of omega-3 fatty acids, and that measures

have been taken to minimise degradation, so consumers do get the

good oil they believe they are purchasing. "

Footnote:

Recognition of the health benefits of omega-3 fatty acids has grown

since the Inuit Eskimos low incidence of heart disease was

highlighted in the 1970s. Their high fat diet is sourced from marine

animals and it has now been established that the omega-3 fatty acids

found in fish play a unique and important role in preventing heart

disease.

Many other benefits have also been associated with consumption of

fish oils including enhanced immunity, improved bone, joint and eye

health and better brain function. Links have also been made to

mental health.

Around the world, food companies have responded to consumer

awareness of these health benefits by creating products with omega-3

fatty acids. These include: breads, spreads, yoghurts and drinks.

Footnote 2: Drs and McLean work on lipids, proteins & their

oxidation. Recent research, at their base, has focused on the

analysis of volatile oxidation products in fish species. This has

been achieved using the only Gas Chromatography Mass Spectrometer -

SPME dedicated to oils in New Zealand.

For more information contact:

Dr Rufus , or Dr Carlene McLean

Crop & Food Research

Tel 03 539 1849

Email R@...

McLeanC@...