A7-OP: MEAT FRESHNESS MONITORING WITH DIFFERENT BIOGENIC AMINE BIOSENSORS
B. Bóka (1), N. Adányi (2), D. Virág (1), A. Kiss (1)
1 EGERFOOD Regional Knowledge Centre, Eszterházy Károly College,
Eszterházy tér 1, H-3300 Eger, Hungary
2 Central Food Research Institute, P.O. Box 393,
H-1537 Budapest, Hungary (bokab@ektf.hu)
Biogenic amines are low-molecular-weight nitrogen-containing compounds of biological importance. Although they are essential to living organisms, consumption of food containing high amounts of them may have toxicological effects. However, in some fermented foods like cheese, higher amount of biogenic amines can be expected, but in non fermented food like meat products they can be present as a consequence of microbial contamination and inappropriate conditions during processing and storage. Therefore, the content of biogenic amines, especially putrescine, cadaverine, histamine and tyramine can be considered as freshness markers and could be used as an indicator of microbial spoilage [1]. For meat quality and freshness determination, microbiological, chemical and sensory methods are the most widespread techniques. The latter are rapid, well accepted but depend highly on trained panels and cannot detect specific food contamination. On the other hand, traditional microbial enumeration methods are usually slow, requiring 2–5 days. Analytical chemical assays for measurement of spoilage indicator compounds like biogenic amines are most often based on different chromatographic techniques like thin layer chromatography (TLC), gas chromatography (GC) and high-performance liquid chromatography (HPLC). These methods are usually time-consuming, and require expensive instrumentation and chemicals, and well-trained experts. Contrary to the above mentioned methods, biosensors offer a simple, rapid and cost-effective solution [2].
The aim of our work was to develop fast enzymatic biosensor methods for meat freshness monitoring. Diamine oxidase (EC 1.4.3.6) from Pisum Sativum, human recombinantmonoamine oxidase A(EC 1.4.3.4) and putrescine oxidase (EC 1.4.3.10) from Kocurea rosea were selected. With diamine oxidase (DAO), the total biogenic amine content was determined because of the broad substrate specificity. Monoamine oxidase A (MAO A) was used for the detection of tyramine and tryptamine content, while putrescine was selectively measured with putrescine oxidase (PUO). The amine specific enzymes were separately immobilized on the surface of a graphite electrode in redox hydrogel with horseradish peroxidase, Os mediator and poly(ethylene glycol) (400) diglycidyl ether (PEGDGE) as crosslinker. The electrodes were fixed in a wall-jet type amperometric cell together with Ag/AgCl reference electrode and platinum counter electrode. The sensors worked in flow injection analysis system (FIA) using a potentiostat (QuadStat 164, eDAQ, USA). The linear measuring range was 0.01-0.5 mM for the PUO sensor (phosphate buffer 66 mM, pH 8.0), for MAO A electrode in tyramine equivalent (phosphate buffer 100 mM, pH 8.0) and for DAO electrode in histamine equivalent (phosphate buffer 100 mM, pH 7.0), respectively.The developed biosensors were tested for freshness monitoring of fish and pork meat samples stored at different conditions. Spun drips from meat were collected from time to time with cooled centrifuge using a special plastic separator [2], and measured by biosensor methods after dilution. The biogenic amine content was also measured by HPLC method for validation [3, 4].
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