Effects of Diazinon concentrations on LC50, hematocrit and clinical signs of Roach Torkemani (Rutilus rutilus caspius) fries of Caspian Sea

Effects of different concentrations of Diazinon on Roach Torkemani (Rutilus rutilus caspius) fries supplied from Ghareh-Soo Fishery Research Station was studied in Gorgan University of Agricultural Science and Natural Resources in 2009 to determine 50% lethal concentration (LC50) for the fish within 96 hours. In this study, 126 Roach fries with mean weight of 3 grams were used. Tests were performed statically based on instructions of O.E.C.D under fixed water quality conditions at the temperature 24±1 and pH 8-8.5 in a completely random trial with five concentrations treatments of Diazinon (5, 5.95, 7.07, 8.48 and 10mg/l) in three replications and the means were compared using Duncan test at 5% significance level. The results indicated that at the end of 96-hour test, LC50 was 7.88mg/l. In this test, clinical signs such as hunched spinal column, thrilling, clot in caudal fin and head, and irregular swimming were observed in the studied fish specimens. In hematological examination, there was a remarkable decrease in percent of hematocrit between concentrations of 5 and 5.95mg/l of Diazinon. By increasing the concentration of this poison, the decrease became slower.Furthermore, there was a significant difference in percent of hematocrit between control group and LC50 group, with mean amounts of 36 and 27%, respectively. Based on the results, Diazinon was classified as toxic pesticide for Roach Torkemani

Effects of different cooking methods on minerals, vitamins and nutritional quality indices of grass carp (Ctenopharyngodon idella)

This study aimed to evaluate the nutritional value (proximate composition, fatty acid profiles, vitamins and minerals) contents and also nutritional quality indices (NQI)) of grass carp (Ctenopharyngodon idella) prepared according to common consumer techniques: raw, poached, steamed, microwaved, pan-fried and deep-fried (in olive oil). In comparison to raw fish fillets, when grass carp was cooked there was an increase in protein, lipid and ash contents. Cooking methods had no significant effect on total n-3 fatty acids except for frying fillets. Lowest and highest content of n-3 was shown in deep-fried and pan-fried samples, respectively. Total n-6 fatty acid of cooked samples increased in comparison to raw samples. Na, K, Mg, P and Zn contents of boiled fish fillets significantly decreased. None of cooking methods had a significant effect a vitamin D. However, vitamin A, B_1 and B_3 contents of cooked fish significantly decreased

Quality enhancement in refrigerated tiger tooth croaker (Otolithes ruber) fillets using chitosan coating containing green tea extract

The effects of chitosan (2%) coating combined with green tea extract (GTE) (1%) on the quality of tiger-tooth croaker (Otolithes ruber) fillets including chemical, microbiological, texture, color and sensory properties during 16 days of refrigerated storage was investigated. The color changes were significantly retared, and the texture parameteres and sensory scores were significantly improved in tiger- tooth croaker coated by chitosan, GTE and chitosan combined with GTE, compared with the control. The coincidental lowered rate of increase total volatile base (TVB) content, thiobarbitoric acid (TBA), peroxide value (POV) and free fatty acids (FFA) were obtained in tiger-tooth croaker coated chitosan+GTE. Chitosan in combination with GTE had higher inhibition on microbial growth and yielded the tigertooth croaker with higher likeness, compared with the other treatments. Therefore, fish coated with chitosan+GTE had the lowest losses in quality during refrigerated storage

The effect of vaacum packaging, chitosan edible film and coating on the sensory evaluation of Spangled emperor (Lethrinus nebulosus) raw fillets stored in refrigerato

BACKGROUND: Lethrinus nebulosus is a fish that is valuable and high demand in the south of the country, therefore it is necessary to keep and Maintain its quality. Therefore, this study was done to evaluate the effect of vacuum packaging, chitosan edible film and coating on the sensory evaluation of Spangeled emperor raw fillets stored in refrigerator. METHODS: After preparation and washing fillets, chitosan solution obtained by dissolving 2% w / v chitosan in acetic acid 1% v / v and chitosan film by casting on the nonstick surface and drying was prepeard. Also chitosan coating was obtained by immersion in chitosan solution and drying at ambient temperature. Fillets after treating in film and coating, was packed (simple and vaccum packaging). Sensory evaluation was done once every 3 days for 12 days. FINDINGS:All the sensory indicators of samples reduced with storage time so that control sample on day 3 and other samples on day 6 got unacceptable sensory score. The samples immersed in chitosan solution (coating) and packed under vaccum condition showed the highest score of the sensory indicators, although there was no significant differences between any of the samples (P>0.05). The lowest and highest values of the texture indicator were related to the control (1.78) and chitosan coating under vacuum packaging (2.71) samples on day 12, respectively. The control and chitosan coating under vacuum packaging samples were had the lowest (1.92) and highest (2.35) value of the odour scores on day 12, although there was no significant differences between any of the samples (P>0.05). Also chitosan coating under vacuum packaging sample were showed The highest values of the color (2.30) and overall acceptance indicators (2.23) on day 12, although there was no significant differences between the samples (P>0.05). CONClUSION:The results of comparative sensory properties of the chitosan edible film and coatings and vacuum packaging in Spangeled emperor showed that the use of chitosan film and coating with and whithout vacuum packaging, lasted the shelf life of Spangeled emperor fillets 3 days more than the control samples