Development of a Novel Method for Rapid Discrimination between Wild and Farmed Sea Bream

Discrimination between Wild and Farmed Sea Bass by Using New Spectrometry and Spectroscopy Methods

European sea bass (Dicentrarchus labrax L.) is one of the most economically important fish species in the Mediterranean Sea area. Despite strict requirements regarding indications of production method (wild/farmed), incorrect labelling of sea bass is a practice still frequently detected. The aim of this study was to evaluate the capabilities of two techniques, Near-InfraRed (NIR) spectroscopy and mass spectrometry, to discriminate sea bass according to the production method. Two categories were discriminated based on the docosahexaenoic and arachidonic fatty acid ratio by using a Direct Sample Analysis (DSA) system integrated with a time-of-flight (TOF) mass spectrometer. The cut-off value of 3.42, of fatty acid ratio, was able to discriminate between the two types of fish with sensitivity and specificity of 100%. It was possible to classify fish production by using multivariate analysis with portable NIR. The results achieved by the developed validation models suggest that this approach is able to distinguish the two product categories with high sensitivity (100%) and specificity (90%). The results obtained from this study highlight the potential application of two easy, fast, and accurate screening methods to detect fraud in commercial sea bass production.

Development of a screening method to rapidly discriminate extravirgin olive oil from other edible vegetable oil by means of direct sample analysis with high resolution mass spectrometry

Extra virgin olive oil is the highest quality olive oil mainly due to its beneficial constituents and nutritional properties. However, olive oil adulteration is a common fraudulent practice by deliberate mislabelling of less expensive oil categories and admixing expensive olive oils with low oils. To protect consumers from such commercial frauds, an easy and fast method to detect the real composition of oil is needed. For this study we used direct sampling analysis (DSA) coupled with a high-resolution mass spectrometer (AxION2 TOF Perkin Elmer) to analyse the fatty acid composition of three types of edible oil: extra virgin olive oil, refined olive oil and seed oil (EVOO, ROO, and SO respectively) to find a marker that could distinguish between them. Good precision in repeatability and reproducibility (RSD% < 15%) was obtained. The fatty acid ratio between the oleic acid/oleic acid dimer was able to distinguish EVOO from the other two types of oil, while the ratio between linoleic and oleic acid was found to discriminate refined oil from seed oil. The development of an easy, fast and cost-effective method can help to limit commercial frauds, increase the number of controlled samples, and enhance food control along the commercial chain.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05063-y.

Wild or Farmed Gilthead Seabream (Sparus aurata)? How To Distinguish between Them by Two-Dimensional Gel Electrophoresis

ABSTRACT

Because the world's wild fish stocks are limited and the market demand is increasing, fish farming has become an alternative food source and a way to reduce costs for consumers. The sale of farmed as wild fish is a fraudulent practice; it is, therefore, important to find new and alternative tools that can help in the fight against fraud to protect consumers and to ensure food traceability. The proteomic profiles of farmed and wild fish differ. With this study we wanted to identify liver protein markers via two-dimensional electrophoresis that would allow us to distinguish wild from farmed gilthead seabream. The liver samples from 32 gilthead seabream, wild and farmed, were stored at -80°C before protein extraction. The samples were subjected to two-dimensional electrophoresis to detect qualitative and quantitative differences. Proteomic analysis showed a protein spot (molecular weight of ∼34 kDa and isoelectric point of ∼6.9) only in the samples from the wild gilthead seabream; liquid chromatography-tandem mass spectrometry identified the spot as ubiquitin. Ubiquitin could be a valid marker to differentiate wild from farmed gilthead seabream; it could be used to ensure continuous monitoring throughout the entire commercial chain and to fight commercial fraud.

HIGHLIGHTS