Changes in biochemical and microbiological quality of silverside during two drying process were investigated. Total fatty acid and amino acid contents in silverside were 5.42 and 10.9 g 100 g )1 fresh sample, respectively, in which, palmitic acid and glutamic acid were the most abundant. N-3 and n-6 polyunsaturated fatty acids (PUFA) levels were 0.59 and 0.62 g 100 g )1 fresh silverside respectively. After hot air and solar drying treatments, Peroxide value and thiobarbituric acid reactive substances of the total lipids increased significantly (P < 0.05) to reach 2.58 and 3.41 meq active O 2 kg )1 oil and 0.87 and 1.27 mg MA kg )1 oil, respectively. Fatty acid profile of non-polar lipid remains unchanged during experimental drying process. However, PUFA (% of total fatty acids) of polar lipid decreased significantly (P < 0.05) during both drying process with lower levels in solar drying process. Drying conditions had a significant effect on the microbiological quality. Therefore, mesophiles and total coliforms increased within drying treatment with higher counts in solar drying process.

This study aimed to estimate the nutritional quality of Sander lucioperca fillets and alterations in lipid quality following hot and cold smoking processes. Our results revealed that the total fat content of zander fillets was 1.86 g/100g. Polyunsaturated fatty acids (PUFAs) were higher than saturated and monounsaturated fatty acids in fresh tissue samples. Arachidonic, docosahexaenoic and eicosapentaenoic acids were the most abundant PUFAs. Differences in the fatty acid compositions of the smoked and fresh fillet were significant, with a decrease in (PUFAs) in the proportion of total fatty acids. The fatty acid profile of the neutral lipids was unchanged after the cold smoking process, whereas PUFAs decreased significantly during both smoking processes, especially the hot smoking process. Our findings showed a partial alteration of polar lipids. Both smoking treatments produced lipoperoxidation and lipid oxidation in the fillets. Other investigational smoking conditions should be tested to reduce such oxidation and hydrolysis in fillets, which could be susceptible to off-flavors and off-odors.

Otolith mass asymmetry can significantly affect the vestibular system functionalities; usually, the X values of mass asymmetry vary between −0.2 and + 0.2 (−0.2 &lt; X &lt; + 0.2). These values can change during a fish life and therefore they are not related to the fish total length. We collected a total of 404 fish specimens from the Gulf of Tunis, including three pelagic species: Sardina pilchardus (Walbaum, 1792) (74 otolith pairs), Trachurus mediterraneus (Steindachner, 1868) (66 otolith pairs), and Chelon auratus (Risso, 1810) (60 otolith pairs) and three benthic species: Gobius niger Linnaeus, 1758 (77 otolith pairs), Mullus barbatus Linnaeus, 1758 (60 otolith pairs), and Trachinus draco Linnaeus, 1758 (67 otolith pairs). The relation between the total length and the otolith mass asymmetry was first calculated and compared, and then was evaluated. The comparison of the otolith mass asymmetry between benthic and pelagic species showed a significant difference (P &lt; 0.05), where the absolute mean value of X does not exceed the critical value (0.2) for all the studied species. No relation has been found between the magnitude of the otolith mass asymmetry and the length in both benthic and pelagic specimens. Environmental factors have an indirect effect on somatic growth and otolith accretion. The significant difference found in this study can be due to the difference between the benthic and pelagic environments.