How to Keep Your Fish Fresh - with the Help of Chromatography

Eating fish is one of the healthiest sources of energy. Fish contains considerable amounts of protein, vitamins, and nutrients such as omega-3 polyunsaturated fatty acids (PUFAs). But fish, like many other fresh produce, can spoil and go off, which is wasted food and can lead to serious illness. But help might be at hand according to a research paper published in the journal Functional Foods in Health and Disease.

In a paper titled Eryngium caeruleum essential oil as a promising natural additive: in vitro antioxidant properties and its effect on lipid oxidation of minced rainbow trout meat during storage at refrigeration temperature, researchers from the Department of Food Safety and Hygiene in Iran have identified an essential oil that can help to stop fish going off in the fridge – and chromatography was at the forefront of the research.

Oxidation of the PUFAs

Oxidation processes occur in many food species and they are frequently associated with aging processes or due to reactions within a foodstuff with another chemical naturally present in the food. Lipids are susceptible to these processes and are one of the important sources of deterioration of foods during processing, storage, distribution, and final processing. Many different compounds can be produced during lipid oxidation and some might be associated with higher mortality and increased disease rates.

PUFAs confer many health benefits to humans including reducing the risk of heart disease and they are reputed to play a role in the neurodevelopment of children. Unfortunately, polyunsaturated fatty acids are particularly susceptible to oxidation. The chemical oxidation of oily fish like rainbow trout is caused by lipid oxidation.

Lipid oxidation is associated with off-flavour tastes and reduced nutritional value. One way to reduce oxidation is to use antioxidants which can stop or delay the initial stages of oxidation. Some foods already use antioxidants to stop the food spoiling. But many of the antioxidants in use are synthetic and highly regulated. It is the search for natural antioxidants that is behind the research from the scientists in Iran.

Essential oils keep fish fresh

Eryngium caeruleum is an herbaceous and flowering plant that grows in northern areas of Iran. The essential oil from the plant’s leaves is known to have antimicrobial properties. The team evaluated the compounds in Eryngium caeruleum essential oil (EEO) using gas chromatography-mass spectrometry. The use of gas chromatography is discussed in the article, Gas Chromatography Troubleshooting Part I – Peak Shape Issues.

After discovering that the oils also may have antioxidant properties, the team mixed the oils in different concentrations with minced rainbow trout meat. The samples were evaluated after 20 days storage at 4°C. The team found that oil at a concentration of 0.4% significantly improved the chemical stability of the fish. They conclude: the results of present study indicate that the use of EEO in the meat industry can develop the novel healthy fish products and improve its chemical stability.