Analysis fish freshness

QMB-based electronic layers were used for many applications. As an example, metaUopoiph5nlns-coated QMB were used in a large variety of application in the fields of food analysis and medical diagnosis. Examples in food analysis fish freshness, food aroma detection, and microbiological contamination of cereals. Noteworthy results in medical diagnosis have been obtained for lung cancer and asthma diagnosis. ... 

K. Mitsubayashi, Y. Kubotera, K. Yano, Y. Hashimoto, T. Kon, S. Nakakura, Y. Nishi and H. Endo, Trimethylamine biosensor with flavin-containing monooxygenase type 3 (FM03) for fish-freshness analysis, Sens. Actuators B Chem., 103(1-2) (2004) 463-467. 

Purine analysis can be achieved with this system, specifically inosine (the co-substrate, with phosphate. Scheme 5.5) can be determined quantitatively using similar methodology. The hypoxanthine ratio ([hypoxanthine]/ [hypoxanthine] + [inosine] + [inosine-monophosphate]) is key measure of fish freshness as hypoxanthine is a product of nucleotide degradation and a sign of spoilage. As mentioned previously, hypoxanthine or xanthine... 

Recently, the use of AR has extended into several other areas, yielding interesting information for cytology, fresh cell/tissue sections, and fluorescence IHC (fluorescence in situ hybridization [FISH]), in addition to adaptations of the method for extraction of nucleic acids and proteins from FFPE tissues for use with modern methods of molecular analysis. In this chapter, the emphasis is on expanded applications in diagnostic cytology, fresh frozen cell/... 

The analysis of fish tissues for ciguatoxin by a newly developed enzyme-immunoassay procedure (26, 27) has been carried out in this study. Three areas of examinations have been attempted (1) the examination of clinically defined and documented and non-toxic consumed fish samples (2) the assessment of freshly caught fishes from the sites in the Leeward part of the island of Oahu where ciguatoxin is found and (3) competitive inhibition with suspension of purified ciguatoxin and closely related structurally similar polyether toxins. 

Sensory. Sensory analysis is one of the oldest accepted methods forjudging seafood quality and freshness. Although fairly accurate, it unfortunately requires trained, experienced panelists to attain accuracy. Perez-Villarreal (( u evaluators experienced in sensory analysis of fish to judge freshness and quality. Results of the study showed sensory scores were better correlated with microbiological analyses, especially total viable counts, than with chemical analyses such as trimethylamine or enine nucleotide decomposition (6). 

In 1998, 3,678 samples were obtained from slaughterhouses (cattle, 1,171 pigs, 587 sheep, 242 poultry, 608) in addition feed samples (137) together with blood serum (185) and urine (285) were obtained from farms. Also in accordance with the revised EU Council Directive 96/23/EC fresh milk (210), eggs (150) and fish (5) samples were analysed. The result of this sampling and analysis programme was that 99.1% of samples were found not to contain detectable residues of veterinary drugs. In total 33 samples contained residues in excess of the MRL or action level. 

Because of the toxic nature of these oxidized components, the authors cautioned regular intake of encapsulated fish oils. The sale of oxidized fish oil products can be considered criminal as they pose potential health risks to the consumer. In addition to ensuring that the consumer is buying the authentic product, it must be fresh, with a clear and realistic shelf-life date indicated. The presence of vegetable oils in a fish oil is best tested for by examination of the sterol composition, as fish oils consist almost entirely of cholesterol and 24-methyl cholesterol (Paganuzzi, 1983). Analysis of the sterol fraction of the oil can often identify the oil, or at least indicate which oils might be present. 

Accuracy and Analytical Quality Control Aspects The analysis of certified reference materials (CRMs) following the same analytical procedures was performed for assessment of the accuracy of the procedure and for quality control (QC). Yet, the available CRMs are mostly freeze-dried, not fresh or deep-frozen. In Table 22.3 an overview of CRMs in a seafood matrix with respect to organic Hg is given. It is certainly beneficial that more and more CRMs are becoming commercially available. Recently, a new CRM for trace elements in a matrix of lyophilized tuna fish (IMEP-20) has been produced [44]. Apart from total Hg (4.32 mg kg-1 dry mass) and Me-Hg (4.24 mg kg-1 dry mass), this material is also certified for other elements such as As, Pb, and Se. 

Figure 9.19 Scale analysis of North Sea houting from Ijsselmeer lA-ICP-MS, a) photograph of a scale, b) part of a scale with laser craters obtained by LA-ICP-MS measurement in line scan modus, c) Sr Ca ratio for nine North Sea houting caught in Ijsselmeer in 2001/2002. The results were sorted into three different types A Fish that only lived in freshwater B Fish that lived for a fairly long period in fresh water, then moved to sea water and returned to fresh water where they were caught C Fish that obviously moved quickly to sea water after hatching (period from hatching in fresh water until the arrival in the sea was to short to measure a ratio that normally indicates fresh water) and returned to...

Draisci and co-workers performed interesting research for the extraction of relatively polar analytes such as musk compounds in Italian fresh water fish (60) and corticosteroids in bovine liver (61). For musk components, alumina was utilized in the extraction cell to hinder co-extraction of lipids. The FFR values for these investigations were in the range 0.002 and 0.05, and in no case did they report problems with the presence of fet during the chromatographic analysis. For corticosteroids, a different concept was used, where fat was selectively extracted with pure hexane, followed by elution of the analytes in a second step. 

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