Assessment of the freshness of fish and poultry meat by fast protein and metabolite liquid chromatography using a new optical sensor

Fresh fish and poultry meat are in high demand on the market: poultry, mainly chicken, is the second most consumed and the most affordable meat product in the world. Fish consumptions varies greatly across regions but in some countries, seafood is the main source of abundant and affordable macro- and micronutrients.
Meat and, especially, fish are highly perishable products: methods and equipment for rapid, objective, and reliable assessing the freshness of fish and meat are crucial for the food industry. Generally recognized reference techniques such as total volatile basic nitrogen (TVB-N), volatile fatty acids (VFA), high pressure liquid chromatography (HPLC), mass spectrometry, or nuclear magnetic resonance (NMR) spectroscopy are time-consuming and require expensive and complex equipment.
We developed a novel chromatographic optical sensor with a deep UV LED photometric detection (255–265 nm) for rapid assessment of meat and fish freshness based on determination of the relative content of adenosine triphosphate (ATP) metabolites. The sensor has a simple and compact design, and relatively low cost; sample preparation and processing of a chromatogram takes less than 30 min.
The sensor was tested on Amur (farmed freshwater fish) and rooster meat, obtained from a local farmer. The samples were kept refrigerated at +4 C°, measurements were taken daily during a 14 days period. All chromatograms show two peaks: the first one is responsible for proteins; the second broad post-protein band is formed due to the overlapping of individual peaks of ATP and its metabolites. As fish and poultry meat are stored, ATP is converted into metabolites with lower molecular weight, which is reflected in the chromatograms – the elution time for the second peak increases. It was shown that this time can be directly associated with the freshness status of a product. As expected, poultry meat showed better storage stability and freshness retention compared to Amur fish.