Effects of whey protein edible coating on bacterial, chemical and sensory characteristics of frozen common kilka (Clupeonellia delitula)

The objective of the current study was to investigate the effects of whey protein coating on the quality of common Kilka during frozen storage. For this study, common Kilka was coated with 20% whey protein concentration. Non-coated Kilka also was used as a control. Coated and non-coated samples were then stored at -18 °C for six months. Bacterial, chemical and sensory properties of the samples were determined in each month. Results showed that Coliform, Escherichia coli and Pseudomonas bacteria contaminations were negative until the end of storage period in the covered samples. Total bacterial counts and Staphylococcus bacteria count were lower in the test samples compared with the control samples. Humidity, protein, lipid, ash and calorie contents were higher in test samples as compared with the control samples, while peroxide value, free fatty acids, thiobarbitoric acid, TVN and pH were lower in test samples. Taste, odor, color, tissue and overall acceptability were studied in the test and control samples. These specifications had a better quality in test samples compared with the control ones. These factors showed a significant difference in the uncoated samples (control) (p<0.05). Significant decrease was observed in bacterial counts in the covered and control samples. According to the statistical analysis in sensory specifications, there was a significant difference between the covered samples and the control ones (p<0.05). According to the results of experiments and statistical analysis, the covered samples had a favorable quality until the end of storage period but the control samples had lost their quality after three months

Protein and lipid changes of FPC produced from Caspian Sea kilkas in VP and MAP during storage at different temperatures

Fish Protein Concentrate (FPC) is a healthy, sustainable and high nutritive product that produced from fish and protein and other nutrients are more concentrated than in the fresh fish. The aim of this research is to study the sustainability of FPC produced from Kilka (combination of three Caspian Sea Kilka species, Clupeonella engrauliformis, C. grimmi and C. cultriventris which were not identified and processed separately) in VP (Vacuum Packaging) and MAP (Modified Atmosphere Packaging) at different temperatures during six months of storage. According to result of chemical analysis performed, protein content was evaluated 91.2%, lipid 0.5%, ash 3.6%, moisture 2.3%, TVN 10 mg/100g and peroxide 5 meq/kg in the produced FPC before packing. Amino acids and fatty acids were also determined. Lipid amount in FPC after 6 months at 35°C in VP changed from 0.50 to 0.45 and in MAP (combined of 60% CO2, 30% N2 and 10% O2), decreased from 0.50 to 0.36. It was also detected that increase in temperature leads to more decrease in lipid content but it was not significant (P>0.05). Protein content of FPC has changed from 91.2% to 73.6% during six months at 35°C in VP and 69.4% in MAP. But at 5°C, protein contents were changed from 91.2% to 88.4% and 81.2% in VP and MAP, respectively; these changes were significant (P<0.05) but the decrease in MAP was again more than VP

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

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

Fillet yield, proximate composition and mineral contents in Indian spiny halibut Psettodes erumei caught from the coastal waters of Bushehr (Persian Gulf)

The objective of this study was to assess fillet yield, proximate composition and mineral contents of the Indian spiny halibut (Psettodes erumei) during different seasons. Fish samples (female = 100 and male = 100) were caught from the coastal waters of Bushehr province and body weight and length were taken to predict fillet weight and yield. Large differences in the fillet yield were observed between seasons. The highest fillet yield (49.4%) was obtained in the samples collected in autumn while samples collected in spring had the lowest yield (42.1%). There was a linear relationship between fish length and fillet weight while no significant correlation was found between fillet yield and body measurements (weight and length). The fat content of Indian spiny halibut was < 1.2% throughout the sampling period. Based on the results, fish collected in all seasons except spring for fillets may lead to a higher production with no significant difference between two sexes

Effect of gamma irradiation on fatty acid composition of rainbow trout (Oncorhynchus mykiss) fillets

The present study was conducted to evaluate the effect of low-dose gamma irradiation (0, 1, 3 and 5 kGy) on fatty acid composition of Rainbow trout (Oncorhynchus mykiss) fillet. Among all of the fatty acids, oleic acid (C18:1) (with mean 33.50±3.02 g/100 g fatty acids) and myristoleic acid (C14:1) (with mean 0.41±0.26 g/100 g fatty acids) were the most predominant and the lowest fatty acids in all irradiated and non-irradiated samples, respectively. Statistical analysis showed that there were no significant differences (P>0.05) in level of all fatty acids, saturated fatty acids (SFA), unsaturated fatty acids (USFA), mono unsaturated fatty acids (MUFA) and poly unsaturated fatty acids (PUFA) between Rainbow trout fillet control and irradiated in 1, 3 and 5 kGy. Therefore irradiation process and different doses of irradiation in this study (1, 3 and 5 kGy) had no significant effect (P>0.05) on fatty acid composition

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

A study on physico-chemicals parameters, environmental pollutants, bacterial and macrobentos distribution at the surface waters, undergrand waters and wastewater of Mangol Dam basin (Mazandaran province)

At the present study, the water quality parameters monthly, environmental pollutants (pesticides, heavy metals and surfactants) seasonally, macrobenthos and bacteria (monthly) were done 2009 t0 2010 that located in Mangol Dam with longitude and latitude 52° 22' 49" N and 43° 15' 43" E, respectively. All water samples were collected from under-groundwater, surface water and wastewater in 12 stations and the results are as follow: The mean concentrations of DO, BOD_5, COD, HCO^3-, CO_3^2-, TA, Ca^2+, Mg^2+, TH, TSS, TDS, Cl^-, PO4^3-, NH^4+, NO^2- and NO^3- were determined about 11.86±0.49, 5.95±0.11, 4.96±0.59, 28.1±6.1, 14.34±1.64, 36.30±2.33, 64.66±2.34, 28.84±1.52, 271.62±8.41, 0.37±0.03, 0.45±0.02, 28.02±1.96, 0.06±0.01, 0.010±0.001, 0.01±0.001 and 0.96±0.03 mg/l, respectively and also temperature, pH and EC were 12.7±0.61°C, 8.00±0.02 unit, 0.57±0.02 ms/cm in all samples. The surface water quality of Haraz River and its tributaries were suitable for usual applications such as aquatic matters, but based on BOD_5 need to more attention for human usages. The water quality index (WQI) of surface water was classified in group II at all stations that shows serious water quality changes due to domestic and agriculture sewage. The groundwater was affected by different matters that caused change of water quality parameters. The wastewater was classified from good to moderate based on BOD5. The quality of wastewater was declined at down-stream with decreasing DO and pH and increasing BOD5 pollutants. The mean concentrations of aldrin and endrin were about 0.66 ± 0.59 and 0.71 ± 1.07 µg/l, respectively. The maximum seasonal concentration of organochlorin pesticides (OCPs) were detected in fall, winter and spring for endosulfan sulfate, γ-BHC, heptachlor, endrin aldehyde compounds about 2.85, 0.34, 0.14 and 0.14µg/l, respectively. The maximum seasonal percentage range of OCPs in fall, winter and spring for endosulfan sulfate, DDD and β-BHC were 42, 25 and 25 %, respectively. The maximum seasonal concentrations during fall, winter and spring were detected in Sorkhroud and Polechelave stations for only Fe about 1.48, 3.3 and 8.22 µg/l, respectively. Also for Hg in spring was determined about 17.2 mg/l. The mean concentration of Zn, Fe and Hg in water sampled were 0.23 ± 1.01 and 1.21 ± 2.00 µg/l, respectively and 4.65± 6.38 mg/l. The maximum concentration of linear alkyl benzene sulfonate (LAS) in summer was 971µg/l. The mean concentration of surfactant during fall, winter, spring and summer was 418.62 ± 52.16 µg/l. The maximum seasonal percentage ranges of surfactant during fall, winter, spring and summer in all stations of sampling were 76, 76, 100 and 100 %, respectively. Tottaly 15 families of macrobenthos were identified in Haraz River. The maximum mean of abundance and biomass in Sorkhroud and Nour-roud stations were 1177±256 ind/m^2 and 3609±935mg/m^2, respectively. During Seasons, the maximum mean abundance and biomass were detected in fall and winter with 1185±444 ind/m^2 and 3891±849 mg/m^2, respectively. Water quality were classified by Hilsenhoff Biotic Index such as Sorkhrood station as "Very Poor", Isar town station as "Fairly Poor" and Karesang and Nor-roud stations as "good" qualification. The maximum of total coli forms and fecal coli forms in surface water were observed in Sorkhrood about 4.9 and 2.3CFU/100ml, respectively. The maximum of total coli forms and fecal coli forms in groundwater were observed in Halomsar and Absak stations about 4 and 1.7CFU/100ml, respectively. Maximum of total coli forms and fecal coli forms in wastewater were observed in Nor-roud station about 3.1 and 1.6CFU/100ml, respectively. The Ovary of nematode in wastewater were observed in Nor-roud and Isar Town stations about 30 through 124, respectively

Isolation and identification of histamine-forming bacteria in frozen skipjack tuna (Katsuwonus pelamis)

In this study a series of experiments were carried out to detect and identify histamine-forming bacteria and analyze histamine content for evaluation of current harvesting and post harvesting procedures. The target fish was skipjack (Katsuwonus pelamis) in which the samples were collected from Oman Sea waters harvested by gillnet or purse seine methods. Bacteriological isolates and the amount of histamine were obtained from the muscle around the gills. The obtained results indicated that the average of total and psychrophilic counts were 7.2×10⁶ and 2.9×10⁶ CFU/g, respectively. Histamine-forming bacteria occurred on a low scale of total bacterial load with the mean of 2.8 ×10² CFU/g. Diverse bacterial isolates were identified as histamine-forming bacteria. Amongst them, Proteus spp. with the highest abundance in samples contributed 24.5% followed by Clostridium perfringens (22.5%), Klebsiella spp. (15.0%), Enterobacter spp. (11.5%) and the other isolates (26.5%). In comparison with USFDA standard, the amount of histamine in 22.2 and 42.2% of the examined samples were 20-50ppm, and >50ppm, respectively. Therefore, there are seafood safety risks in the current harvesting and post harvesting methods used in skipjack industry and proper preventional methods for histamine formation are recommended

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)