The determination of the shelf-life of pasteurized and non-pasteurized sardine (Sardina pilchardus) marinades stored at 4 °C

In this study the shelf‐life of sardine marinades was investigated. After the marination process, sardine fillets were packed into glass jars with 2% citric acid, 4% sodium chloride and spices. The effect of pasteurization at 70 °C for 20 min on the shelf‐life of the sardine marinades was determined. At the end of 6 months storage the differences between thiobarbituric acid, free formaldehyde (FA(ex)), free and bound formaldehyde (FA(dest)) and peroxide value of pasteurized and non‐pasteurizated marinades were not significantly (P > 0.05) different, while the difference between total volatile basic nitrogen, trimethylamine, pH, total plate count and lactic acid bacteria count of pasteurized and non‐pasteurized marinades were. The shelf‐life of both pasteurized and non‐pasteurized sardine marinades was found to be 5 months at 4 °C.     

Production and quality of fish fingers from different fish species

Abstract Production of fish fingers was achieved by using fish species such as sardine (Sardina pilchardus, Walbaum, 1792), whiting (Merlangius merlangus, Linnaeus, 1758) and pike perch (Sander lucioperca, Linnaeus, 1758). Quality changes of battered fish patties during a period of 8 months at –18 °C were investigated. According to the results of microbiological and chemical analysis, fish fingers were found to be within acceptable limits during frozen storage for 8 months. However, sensory analysis showed that, at the end of the frozen storage, fish fingers made from sardine could not be consumed because of rancidity.     

Chemical,enzymatical and textural changes during marination and storage period of sardine (<Emphasis Type="Italic">Sardina pilchardus</Emphasis>) marinades

In this study frozen fillets of sardine (Sardina pilchardus) were used to make marinades. The marinating process was performed in 7% acetic acid and 14% sodium chloride in barrels. The fish:solution ratio was (1.5:1). After the marination process, sardine fillets were packed in glass jars in two different formulations fish:solution ratio of (1.5:1); the first formulation contained 2% acetic acid and 4% sodium chloride with tomato sauce and spices and the other was 2% citric acid and 4% sodium chloride with lemon and also the same spices. Pasteurization process had been applied on half of the jars at 70 °C for 20 min. Chemical, enzymatical and textural changes during marination and 6 months storage period of sardine marinades were determined. The results obtained in proteolytic activities correlated well with the observed texture measurements according to time of storage. A decrease in the histidine content and an increase in glutamic acid and aspartic acid contents of marinated sardines were determined. Histamine levels were lower than the toxic limit (100 mg/kg) during the marination and storage period of sardine marinades.     

Screening for antibiotic residues in the trout by the Four Plate test,Premi test and ELISA test

The effectiveness of various assay systems for the examination of trout was investigated. The Four Plate test (FPT), Premi test and ELISA test were used for determining sulfadiazine/trimethoprim residues in trout. According to the results of the Four Plate test, when trouts were fed with pellets containing antibiotics (sulfadiazine/trimethoprim), the inhibition zones increased according to duration of feed application. In the control group, no inhibition zones were detected. The concentration of the residues accumulated and reached a plateau after 5 days. The antibiotics were detectable in the same concentration as on day 10, but 5 days later (on day 15) they were no longer detectable in the trout by EEC FPT. In contrast to the FPT, 5 days after discontinuing the medicated diet, there were still residues detectable by the Premi test and ELISA test on day 15. According to the ELISA test results of the trout; from day 1 to day 10 the results of sulfadiazine residues were found to be 4.18, 8.02, 9.13, 20.10, 21.32, 20.52, 20.75, 20.99, 20.90, 20.32 ppb, respectively. On day 10, the antibiotics were detectable in the same concentration. On day 15, sulfadiazine residues were found to be 6.82 ppb, but 5 days later (on day 20) they were no longer detectable in the trout. EEC Four Plate method presented less sensitivity and effectiveness in the detection of sulfadiazine.     

Microbiological,chemical and sensory assessment of mussels (<Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis>) stored under modified atmosphere packaging

Wild mussels (Mytilus galloprovincialis), were packaged aerobically under vaccum packaging(VP) and modified atmosphere packaging (MAP (50%/50% CO₂/N₂: M1, 80%/20% CO₂/N₂: M2, 65%/35% CO₂/N₂: M3), and stored at 2 ± 1 °C. Quality evaluation was carried out using microbiological, chemical and sensory analyses. Microbiological results revealed that M2 and M3 delayed microbial growth compared to M1. Of the chemical indices determined, the TVB-N and TMA-N values of M2 remained lower than the proposed acceptability limits of 35 mg N/100 g and 8 mg N/100 g, respectively, up to 8 days of storage. All of the MAP and VP mussel samples exceeded these limits after 12 days of storage. All samples retained desirable sensory characteristics during the first 8 days of storage. Based on microbiological and chemical analyses along with sensory evaluation, M2 and M3 gave a longer shelf-life compared with VP and M1. M2 gas mixture was the most effective for mussel preservation.     

Effects of using slurry ice during transportation on the microbiological, chemical, and sensory assessments of aquacultured sea bass (Dicentrarchus labrax) stored at 4 degrees C

Slurry ice, a biphasic system consisting of small spherical ice crystals surrounded by seawater at subzero temperature, was evaluated as a new chilled storage method for whole sea bass (Dicentrarchus labrax) a sparidae fish species of remarkable commercial interests. In this study two different group of chilling methods were used during transportation; in slurry ice packaged (Group A), and flake ice packaged (Group B). The effect of this advanced system during transportation on quality losses and the shelf life of aquacultured sea bass was evaluated. Mesophilic counts for sea bass exceeded 7 log cfu/g, which is considered the maximum level for acceptability for freshwater and marine fish after 13 days for groups A and B. On day 13 TVB-N values of groups A and B, reached the legal limits (35 mg/100 g set for TVB-N) for consumption. According to the results of sensory analyses, up to day 9 all the groups were determined as "acceptable" but on day 13 the groups A and B were no longer acceptable. The main negative aspect related to quality loss in slurry ice group corresponded to the appearance of eyes and gills. Using slurry ice during transportation did not extend the shelf life of sea bass stored at 4 degrees C.     

Characterization of the absorption of histidine and lead by Juglan regia L., Platanus L., and Pinus nigra L. using high-performance liquid chromatography–mass spectrometry and inductively coupled plasma–mass spectrometry

High-performance liquid chromatography–mass spectrometry and inductively coupled plasma – mass spectrometry were used for the determination of histidine and lead in Juglan regia L., Platanus L., and Pinus nigra L. leaves from industrial areas including Gaziantep City and Bursa City, Turkey. Distilled water was used for the extraction of histidine from plant material at 90°C for 30 min. The flow rate of the mobile phase, fragmentation potential, injection volume, and column temperature were optimized to be 0.2 mL min^?1, 70 V, 15 µL, and 20°C for the determination of histidine. The concentrations of histidine were from 7–9 mg kg^?1 for Juglan regia L., 2–5 mg kg^?1 for Platanus L., and 1–7 mg kg^?1 for Pinus nigra L. The concentrations of Pb were from 1–42 mg kg^?1 for Juglan regia L., 1–4 mg kg^?1 for Platanus L., and 1–62 mg kg^?1 for Pinus nigra L.     

Alkaline neutralization of crude soybean oil by various adsorbents

The effect of sodium hydroxide in neutralization was increased by using various adsorbents. NaOH in various concentrations was attached to the particles of Kieselguhr, Celite and Bentonite. The neutralization reaction was performed at ambient temperature, and different reaction times were applied. The soap formed after reaction was removed by centrifugation; thus, washing and drying steps were omitted. The amount of remaining soap, the acidity and color of oils were determined after each treatment. According to the results, free fatty acid neutralization in crude oil was achieved by Kieselguhr application. In this process, 9.5% NaOH was applied for 60 min of reaction time. The free fatty acid content of crude oil was decreased from 0.56 to 0.14%, and the remaining soap was found at 34 mg/kg after centrifugation. The use of adsorbents increased the efficiency of NaOH in the neutralization reaction and in the removal of soap from the neutralized oil. Neutralization with support material is a new and promising approach. The application is energy saving, more practical and in accordance with the strict environmental legislation about waste disposal.     

Comparison of IEF patterns of sarcoplasmic proteins of fish from North Atlantic and Aegean Sea

Identification of processed fish lacking morphological characteristics is of growing importance in the times of increasing global trade and illegal fishery. Protein electrophoresis techniques, like isoelectric focusing (IEF) of water-soluble proteins, are fast and inexpensive tools for identification of raw fishery products. Protein profiles of raw fish or fillet of the same species were found to be remarkably constant. However, it cannot be excluded that protein patterns of fish of the same species from distant stocks may show some variation.The protein profiles of commercially important fish from different fishing grounds were determined by collecting samples of 38 fish species from Aegean Sea and Turkish fish farms and of five species from North Atlantic waters. The raw fillet of the fish was analysed by IEF of water-soluble (sarcoplasmic) proteins. Species-specific protein profiles were obtained suited for identification of raw fish or fillet. When protein patterns and pI values were compared between Mediterranean and North Atlantic fish of the respective species, only minor differences were observed. These differences were related to the intensity of protein bands, but not to the position within the pH gradient of the IEF gel.The pI values (isoelectric points) of the prominent protein bands of the fish were determined to be used as a database.