Antioxidant effect of ascorbic acid on the quality of cobia (Rachycentron canadum) fillets during frozen storage

The effect of aqueous solutions of ascorbic acid (AA) on the rancidity development in Cobia (Rachycentron canadum) fillets during frozen storage was studied. Cobia fillets were treated with ascorbic acid (AA 0.25% and AA 0.5%) then stored at -18°C up to 6 months. Rancidity development was measured by several biochemical indices including free fatty acids (FFA), peroxide value (PV), and thiobarbituric acid (TBA) and complemented by the sensory analysis (odor, consistency and appearance). In addition, pH and expressible moisture (EM) were measured during 6 months storage. Proximate composition was also determined in the first day. TBA, PV and FFA levels increased on all treatments due to lipid oxidation. Ascorbic acid showed antioxidative effect on Cobia fillets during frozen storage as indicated by TBA, PV and FFA levels. Results showed that free fatty acid, primary and secondary oxidation products, EM and pH value of AA-treated samples were significantly lower than those of the control samples (P<0.05). A gradual decrease (P<0.05) in sensory analysis were observed as the storage time increased. Results of our investigation revealed that ascorbic acid retarded oxidative changes in frozen Cobia fillets whereas AA 0.25% was not as effective as AA 0.5% on oxidative stability. Best oxidation inhibition results on fish fillets were obtained when employing a 0.5% AA solution

Chemical, microbiological and sensory evaluation of gutted kilka coated with whey protein based edible film incorporated with sodium alginate during frozen storage

The effects of whey protein (12%) and sodium alginate (0.5%) on chemical, microbial and sensory changes and shelf life in kilka during frozen storage are investigated for up to 6 months. Total bacteria count and Staphylococcus bacteria counts(2 / 51 and 1 / 44 log CFU/g) in coated samples showed decrease in comparison with control samples(3.21- 2.28 log CFU/g). Moisture of coated samples had significant increase than control treatment (p<0.05). Protein, lipid, ash and calorie were higher in test samples as compared with the control samples. Free fatty acids, TBRS, peroxide value, TVN and pH in coated samples showed significant decrease in comparison with control (p<0.05). Sensory evaluation of coated samples showed significant difference in comparison with control (p<0.05). It is suggested that whey protein edible coating incorporated with sodium alginate can enhance quality and increase shelf life of kilka fish in storage of freezing up to 6 months

Impacts of whey protein edible coating on chemical and microbial factors of gutted kilka during frozen storage

The aim of the present study was to investigate the impact of whey protein coating on quality and shelf life of Kilka fish. Whey protein edible coating was prepared in three different concentrations, including 3, 7, 10 and 13%. Then gutted Kilkas were coated for 1h, packed in polyethylene dishes with cellophane blanket and stored at -18 °C. Total microbial count, total volatile nitrogen (TVN) and moisture evaluation were carried out within 0, 1, 2, 3 and 4 months (sample size: 75 packages, weighted 250 grams each). Results showed that there was no significant difference between total microbial count and total volatile nitrogen among samples (p>0.05). Moisture of coated samples with 13% concentration of whey protein had significant difference with other treatments (p<0.05) suggesting that whey protein edible coating with 13% concentrations can enhance quality and increase shelf life of Kilka fish in storage of freezing up to 4 months

Chitinase isolated from water and soil bacteria in shrimp farming ponds

Chitinases have received attention because of their wide applications in the medicine, biotechnology, agriculture, waste management and industrial applications such as food quality enhancer and biopesticide. Excessive use of insecticides has led to several problems related to pollution and environmental degradation. In this study, isolation and identification of native bacterial strains with chitin hydrolysis activity, took place from water and soil of shrimp culture ponds in Bushehr and Abadan. To investigate the capacity of our chitinase for using in insecticide, biochemical properties of selected chitinase obtained in this research were compared to that of produced by Bacillus cereus p-1, isolated from an insecticide tablet. In this research, three mesophilic strains containing: Serratia marcescens B4A, Citrobacter freundii B1A and Bacillus cereus B3R were isolated. Results showed a 1600 bp band corresponding to chitinase gene. The similarity between temperature and pH profile and stability of chitinase was extracted from native bacteria and ones was obtained from Bacillus cereus p-1 implied that chitinase extracted from Serratia marcescens B4A has potential application in industry

Effects of dietary Bacillus subtilis on growth performance and immune responses, in rainbow trout, Oncorhynchus mykiss (Walbaum, 1792)

Four hundred and eighty five rainbow trout (76 ± 6.44 g mean weight) were acclimated to laboratory conditions and then randomly divided into four groups of tanks in triplicate. The first group (Group 1) was fed on a commercial diet (control) without Bacillus subtilis supplementation. The second, third and fourth groups (Group 2, Group 3 and Group 4, respectively) were given a diet supplemented with 1, 5 and 10 g probiotic powder (containing 8×10^7 CFU g^-1 Bacillus subtilis) per kg commercial feed. Growth performance, immune responses and glucose levels were analyzed on days 0, 22 and 44. The results showed that dietary Bacillus subtilis supplementation significantly (p0.05) was observed in weight gain rate (WGR) between the control and group 2. On the effect of dietary Bacillus subtilis on serum lysozyme, it was observed that group 3 and group 4 did not show any significant differences in serum lysozyme activity and serum total antibody on day 44. Results of alternative complement activity, showed significant increase during the experimental days (p<0.05). Results on glucose assay showed that group 3 had the lowest glucose level (13.71 mg/dL) which was not significantly different than that in other groups on day 44. Fish diet supplementation with 5 g probiotic powder (Group 3) is preferable for immune system responses; however, high dose of Bacillus subtilis may be helpful to improve growth performance in rainbow trout, Oncorhynchus mykiss (Walbaum, 1792)

Monitoring of Cochlodinium polykrikoides blooms as a harmful phenomenon in the Persian Gulf (2010-2011)

The monitoring of the harmful bloom of Cochlodinium polykrikoides in the northern Persian Gulf was studied during 2010 to 2011. The results revealed that in the waters of Hormozgan Province, the Diatoms and Dinoflgellates had the highest frequency. No significant difference was found for amount of nutrients in three sub- regions. The bloom of C. polykrikoides was higher in central sub-region in spring and was occurred in the eastern sub-region in summer, but no mortality of fishes was recorded. In Bushehr Province, four classes of Bacillaryophyceae, Cyanophyceae, Dynophyceae and Prymnesiophyceae were determined. Furthermore significant different values of nutrients were recorded. In waters of Khuzestan Province, different values of NH4 were measured for different months. In total, the measured ratio of N: P in all months was lower than Redfield Ratio (16:1) in which subsequently the environmental condition was not suitable for bloom of C. polykrikoides

A review on fish lipid : composition and changes during cooking methods.

Fish lipids are known to be beneficial for human health since they are rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). This benefit can be affected by some processing or cooking methods. The effects of different cooking methods on lipid content and fatty acid composition of different fish species have been previously studied. In this article, the fish lipid characteristics and their changes during different cooking methods were reviewed. The fat content and fatty acid composition of fish vary according to the species, season, and environmental conditions. The fish lipid characteristics also change during different cooking processes. Frying generally gives higher changes in the fish lipid composition than other cooking methods. For example, frying results in higher losses of DHA and EPA (compared to other cooking methods). Further, the lipid changes occurring during frying depend on the fat content of the fish, the frying oil composition, and the type of frying technology

Effects of different concentrations of sodium alginate as an edible film on chemical changes of dressed kilka during frozen storage

The aim of this study was to investigate the effects of sodium alginate edible coating with concentrations of 0/25, 1/25, 0/75 and 1/75% (W/V) on chemical changes of dressed Kilka during frozen storage. Prepared samples of Kilka fish have been coated for 1 h with the dipping method. Coated and uncoated samples have been packed in polyethylene dishes with selphon coverage (75 packs of 250 g). Chemical parameters (moisture, ash, protein, TVN and lipid) were examined in frozen storage at -18ºC for 4 months. SPSS Statistical Software was used for data analysis, using One Way ANOVA test. Significant reduction was found (P<0.05) in moisture value with increase of sodium alginate concentration during the study. Significant differences were found in TVN values during the third and fourth months but there were no significant differences (P<0.05) in ash and protein content. The highest content of TVN was found in control samples and use of sodium alginate edible coating affected the reduction of TVN, prevented the lipid oxidation, increased the shelf-life of Kilka and reduced the moisture

Gonads tissue changes of Chalcalburnus mossulensis (Heckel, 1843) infected by Ligula intestinalis (Cestoda)

Chalcalburnus mossulensis from the cyprinidae family is one of the indigenous fish in Gheshlagh Lake of Kordestan, Iran. Ligula intestinalis is one of the infective parasites among various species of fish and causes gonads atrophy. In this study, after detection of species and age of samples, the effects of this parasite on gonads tissues and sexual maturation of Chalcalburnus mossulensis were investigated. By seasonal sampling 144 samples were collected. After investigatiing gonad tissue samples, it was clear that, there is a significant difference between the means of male and female gonads maturation rate in infected and non infected samples (p< 0.05). Infection by Ligula intestinalis can be the reason for lack of gonads maturation. In addition, the abnormal degenerative changes like, absorption follicle, hemorrhage and infiltration of inflammation cells in ovary tissues of infected fish were seen. In testicle tissue, dispersed hemorrhage, atrophy and MMC (melano-macrophage center) were seen as pathological signs. So the spread of this parasite in different water sources is important as the point the maintenance of native species and cultivated fish

Detection and identification of white spot syndrome virus (WSSV) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) of Litopenaus vannamei from Bushehr and Sistan and Baloochestan provinces (Iran), during 2009-2010

The first time the white spot disease (WSD) and IHHNV were reported in Iran was in 2004 and 2008, respectively in Bushehr Province. In Sistan and Balochestan province only the WSD was reported in 2008.The aim of this study was detecting these two viral diseases in these provinces, during December 2009 to April 2010. A total of 364 samples were collected according to suspected gross signs from hatcheries and shrimp farms in Bushehr and Sistan and Blochestan provinces (I.R. Iran) respectively, including larvae (72, 43 samples), post larvae (48, 37 samples), juveniles (57, 32 samples), sub adults (39, 22 samples) and broodstock (29, 13 samples) of Litopenaus vannamei . WSD was detected from juveniles (23 samples), sub adults (14 samples), and broodstock (14 samples), and IHHNV was also detected from juveniles (16 samples), sub adults (9 samples) and broodstock (5 samples) based on gross signs, PCR and histopathological changes from Bushehr province but from Sistan and Blochestan province only WSD was detected from juveniles (26 samples), sub adults (18 samples) and broodstock (7 samples). Histopathological observations of WSSV showed basophilic Cowdry type A inclusion bodies in all tissues such as gills, haematopoietic tissue, cuticle epithelium, lymphoid organ and connective tissue. However histologically, the hepatopancreas tissue showed vacuolization of B cells , without inclusion bodies, but histopatholgical changes caused IHHNV including eosinophilic Cowdry type A inclusion bodies which were ectodermal, mesodermal and rarely endodermal