Effects of frying by different frying oils on fatty acid profile of silver carp (Hypophthalmichthys molitrix)

The study aims to determine the influence of frying (shallow and deep) with olive, canola and sunflower oil on fatty acid composition of silver carp. Frying by olive oil and canola oil increased the monounsaturated fatty acids (MUFA) significantly (p<0.05) that consequently decreased saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA) and ω-3 fatty acids. Frying by sunflower oil increased PUFA significantly (p<0.05), which caused to decrease in SFA and MUFA. The ω-6/ω-3 ratio of control samples (0.224) after shallow fat frying and deep frying, increased to 1.287 and 0.615; to 2.290 and 1.538; and to 9.381 and 5.950 by olive oil, canola oil and sunflower oil, respectively. Results suggest that frying oil can change the fatty acid composition of fish. The changes are depending to the kind of frying oil and method of frying which used

Fatty acid composition of fresh and smoked Black and Caspian Sea sprat, Clupeonella cultriventris (Nordmann, 1840) treated with different salt composition

The effect of salting by different salt composition on fatty acid profile studied in hot smoked Black and Caspian Sea sprat, Clupeonella cultriventris. After initial prepare activities, samples were exposed to brining process within two salt concentrations including of 100 % NaCl (treatment 1 or T1) and 75 % NaCl- 25 % KCl (treatment 2 or T2) under 15% brine solution for 3 hrs. The smoking process included turning the samples into drying and hot smokes by slow and high rates of smoking machine (Atmoos) set and packaged. Fatty acid profiles of treated samples were compared with fresh fish samples (control). Smoking process decreased the content of SFA and contemporary increased the content of PUFA in comparison to control samples. These changes were slightly higher in T2. N-3/n-6 ratio of control samples (7.30) was increased in T1 samples (7.71) and decreased in T2 samples (6.86) after smoking process. Atherogenic index (AI) value was decreased after smoking process in both treatments with higher decrement for T2. Thrombogenic index (TI) value was also decreased after smoking process in both treatments. Partial sodium replacement did not affect fatty acid composition, PUFAs content, AI and TI values

The influence of sodium chloride replacement with potassium chloride on quality changes of hot smoked kilka (Clupeonella cultriventris caspia) during storage at ± 4°C

The aim of this work was to study the effect of sodium chloride replacement with potassium chloride on quality changes of hot smoked Kilka during storage at ± 4°C. To achieve this, after initial preparation, samples were exposed to brining process in two salts. This study was designed in two stages: in the first stage, different levels of salt replacement were used to select the best smoked treatment based on sensory test. In this stage, treatments were as: control (100% of NaCl), treatment 1 (75%NaCl/25%KCl), treatment 2 (50% NaCl/50%KCl), treatment 3 (25%NaCl/75%KCl), treatment 4 (100% of KCl). Samples were processed at slow and fast speed smoking for about 4 h, cooled and then tested by test panel. In the second stage, biochemical changes of selected treatment (treatment 1) were compared with control samples during storage at ± 4°C for 15 days. There were no differences (p>0.05) in content of fat, moisture, ash and TBA indices between control and treatment 1. Protein levels and salt intake were significantly (p<0.05) increased while the TVB-N and PV indices decreased in treatment 1. The results indicated that 25% sodium replacement with potassium is desirable for this product

Effect of different levels of dietary betaine on growth performance, food efficiency and survival rate of pike perch (Sander lucioperca) fingerlings

A 6-week feeding experiments were carried out to determine the effects of different levels of dietary betaine on growth performance, food efficiency and survival rate of pike perch which has a critical period during transition feeding. Fingerlings of pike perch were fed with live food (treatment A), without betaine added to biomar (treatment B), 1% betaine added to biomar (treatment C) and 2% betaine added to biomar (treatment D) in 1000 l concreted tanks. 200 fingerlings (1.50 g, mean weight) were stocked in each tank and fed up to 7 meals per day. Higher increment in body weight (4.99 ± 0.73 g), specific growth rate (3.90 ± 0.06) and food efficiency (104.42 ± 4.27) were obtained with treatment D (2% betaine added to biomar). This treatment also showed significant (P<0.05) decrease in food conversion ratio (0.93 ± 0.04) in comparison with other treatments. Highest survival rate was observed in treatment B (biomar without betaine) with a 34.5 % rate and greatest cannibalism (1.03 ± 0.01) was found in treatment D, respectively. It was concluded that betaine could increase the palatability and acceptability of food and could be suitable to weaning the pike perch fingerlings to artificial diet

Effects of genistein on melanosis and microbial quality of Litopenaeus vannamei during ice storage

Utilization of genistein as a natural inhibitor was studied alone and in combination with conventional treatments on melanosis and microbial quality of fresh L. vannamei during 10 days ice storage. Treatments were as followed: A (dipping samples in distilled water), B (dipping in 1.25 % sodium metabisulphite solution), C (dipping in 0.01 % genistein + 2% glycerol solution), D (dipping in 0.1 % genistein + 2% glycerol solution), E (dipping in 1% NaCl + 0.05 % EDTA + 0.5 % ascorbic acid + 0.5 % lactic acid solution), F (dipping in 0.01% genistein + 2 % glycerol + 1 % NaCl + 0.05 % EDTA + 0.5 % ascorbic acid + 0.5 % lactic acid solution) and G (dipping in 0.1 % genistein + 2 % glycerol + 1 % NaCl + 0.05 % EDTA + 0.5 % ascorbic acid + 0.5 % lactic acid solution). Results showed that G treatment was more affective on inhibiting of melanosis in L. vannamei. Mesophilic and psycrophilic bacterial counts in G treatment were lower than other treatments during ice storage

The impact of lipid content, cooking and reheating on volatile compounds found in narrow-barred Spanish mackerel (Scomberomorous commerson)

Effects of four cooking methods (microwave cooking, grilling, steaming and shallow fat frying) and reheating by microwave on volatile profile in S. commerson were evaluated. Thirty compounds were identified in GC-MS analysis of raw samples. The number of volatile compounds had increased to 36, 46, 45 and 45 compounds in microwave cooked, grilled, steamed and shallow fat fried samples, respectively. Total concentrations of volatile had increased from 72.80 to 111.06, 74.25, 112.19 and 92.37 μg/kg, respectively. The concentration and new flavor compounds were increased by chill-reheating, due to the fast oxidation. The concentration of alcohol and aldehydes increased significantly (P<0.05). The hexanal amount also increased in all samples and indicated a marked development of warmed-over flavor. Quantitative and qualitative (P<0.05) differences were observed in volatile compounds between raw and cooked samples

Amino acid and fatty acid profiles of materials recovered from Prussian carp, Carassius gibelio (Bloch, 1782), using acidic and basic solubilization/ precipitation technique

Isoelectric solubilization /precipitation (ISP) process was used to isolate protein from muscles of Prussian carp, Carassius gibelio (Bloch, 1782). Fish protein and lipid were recovered from whole gutted Prussian carp using acidic and basic isoelectric solubilization/precipitation followed by assaying amino acid and fatty acid profile. Essential amino acids content in acidic and basic pH treatment of ISP of Prussian carp were 216.6 and 218.7 mg.g-1, respectively. Results showed that identified amino acids in Prussian carp protein isolated by ISP method, could meet all needs of adults, but a supplementary protein must be used for children. Limiting amino acids in both acidic and basic treatments were methionine and cysteine. Nineteen fatty acids of saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acid (PUFA) groups were identified in lipid recovered in isoelectric solubilization/precipitation process. Total PUFA in basic treatment was noticeably higher than in acidic one. N-3/n-6 ratio in basic pH treatment was also higher than in acidic one

Serum profiles of calcium, phosphorus, magnesium, vitamin D and parathyroid hormone in Caspian horses during different seasons

Minerals play an essential role in the normal vital process. Calcium, phosphorus and magnesium are the most abundant minerals. Vitamin D and parathyroid hormone play a key role in regulation of their homeostasis as well. The aim of this study was to evaluate calcium, phosphorus, magnesium, vitamin D and parathyroid hormone on 30 Caspian horses of Guilan Province (south of the Caspian Sea) in two different seasons. So that, 15 stallions and 15 mares were sampled at the age groups ≤ 3 years and > 3 years, respectively. Fasting blood samples were collected twice, in August and January 2015 from jugular vein of horses. Serum calcium, phosphorus and magnesium were measured by colorimetric methods, while 25(OH)D3 and parathyroid hormone were measured by ELISA. The calcium (11.50 vs. 14.25 mg dL-1 ), magnesium (2.13 vs. 3.72 mg dL-1 ) and vitamin D (1.66 vs. 2.48 ng mL-1 ) levels were lower in winter than in summer (P < 0.05). The Caspian horses had higher phosphorus (4.52 vs. 3.26 mg dL-1 ) in winter than in summer (P < 0.05). Effect of sex on the measured parameters was not significant. Effects of age on the calcium, magnesium, vitamin D and parathyroid hormone levels were not significant, but ≤ 3 year - old horses had higher phosphorus (4.63 vs. 3.15 mg dL-1 ) than > 3 year - old ones (P < 0.05). The vitamin D level of mares was higher (3.10 vs. 1.43 ng mL-1 ) in summer than in winter (P < 0.05). Effects of sex, season, age and their interactions on parathyroid hormone were not significant. In conclusion, calcium, phosphorus, magnesium and parathyroid hormone levels in Caspian horses were within their physiological range, but vitamin D was low without any signs of deficiency. The Caspian horses had lower calcium, magnesium and vitamin D levels in winter than in summer

Shelf-life determination of tiger-toothed Croaker (Otolithes ruber) during flake ice storage

Quality of tiger-toothed croaker stored in flake ice was studied for 19 days by sensory, chemical (total volatile basic nitrogen (TVB-N)), (thiobarbituric values (TBA)), pH and microbial (total viable count, TVC) methods. Sensory scheme was modified according to the panelists perception and a specific schema was created for this fish. Sensory analyses showed that: "gills color and odor", "convexity of eyes", "peritoneum" and "elasticity of flesh" are the best sensory parameters. Results of sensory and microbial analyses had high correlation. Total viable count of flesh was 2.86 log cfu g-1 at first day and reached the limiting level of TVC (106) after 15 days of storage (P<0.05). TVB-N levels were 15.31mg/100 g tissue at the first day of storage and reached 36.52mg/100 g at the end of storage day (P<0.05). Measuring amounts of TVB-N showed that total volatile basic nitrogen is a good quality index for tiger-toothed croaker during ice storage. The initial level of TBA was 0.83mg of malondialdehyde per kg flesh (mg MDA/kg) and increased to 3.75mg MDA/kg at the end of storage. TBA levels were less than limiting level (5mg MDA/kg) over the period of storage. According to the results, shelf-life of tiger-toothed croaker was determined 15 days during ice storage