Preservation of Stuffed Mussels at 4°C in Modified Atmosphere Packaging

The stuffed mussel is a traditional, ready-to-eat food in Turkey which is produced by cooking rice and various spices filled inside the mussel. This article examines the effect on sensory, chemical, and microbiological parameters of stuffed mussels of two gas mixtures—MAP1 50% N₂/50% CO₂ and MAP2 100% CO₂—used as modified atmospheres for cold storage at +4°C. Air packaged samples were chosen as the control group. Based primarily on sensory characteristics, MAP1 gas mixture was the most effective for stuffed mussel. According to sensory results, it has been determined that the control samples kept until the 11th day, while the MAP1 and the MAP2 groups kept until the 13th day. Of the chemical indices determined, the TVB-N values of MAP1 and MAP2 remained lower than the proposed acceptability limits of 20 mg N/100 g, up to 13 days of storage. Microbiological analysis results did not find any differences between the groups. It was found that the shelf life of air and MAP1-MAP2 packaged samples were 7 and 11 days, respectively.     

Bleeding of Farmed Atlantic Cod: Residual Blood,Color, and Quality Attributes of Pre- and Postrigor Fillets as Affected by Perimortem Stress and Different Bleeding Methods

The main objectives of the study were to (a) assess the effect of perimortem stress on blood drainage, (b) compare the efficiency of gill cutting and direct gutting as bleeding methods, and (c) compare pre- and postrigor filleting strategies for presence of residual blood in Atlantic cod fillets. Anesthetized cod had significantly higher drainage of blood compared to stressed fish. Nevertheless, the visual assessments of residual blood were not affected by stress or bleeding method. Some minor, but significant, differences between pre- and postrigor fillets were found. Stressed fish were initially less light in color than those unstressed, but after ice storage there was no noticeable difference. However, initially, the largest difference in fillet color was due to different bleeding methods. Fillets cut from fish subjected to gill cutting were lighter and less red in color than those bled by direct gutting. After 7 and 21 days of storage, the color differences observed in fresh and salted fillets, respectively, were mainly due to the different rigor status when they were filleted, indicating that fillets cut postrigor were superior to fillets cut prerigor. Prerigor filleting resulted in lower water holding capacity after ice storage in anesthetized, direct gutted cod.     

Functional changes in digestive enzyme activities of meagre (Argyrosomus regius; Asso, 1801) during early ontogeny

The ontogenesis of main pancreatic and intestinal enzymes was investigated in the recent promising Mediterranean candidate species of meagre, Argyrosomus regius, during larval development until 40 days after hatching (DAH). The green-water technique was carried out for larval rearing. Whole-body homogenates were used for enzymatic analysis in larvae younger than 15 DAH; after this date, older larvae were dissected into two segments as pancreatic and intestinal segment. Trypsin was detected as early as hatching and sharply increased concurrently with age and exogenous feeding 15 DAH, but constant decline was observed until the end of experiment. Amylase was determined at 2 DAH and sharply increased 10 DAH. Then, slight decreases were found between 10 and 15 DAH, and then slow alterations were continued until the end of the experiment. Lipase was firstly measured on day 3; then, sudden decline was observed between 20 and 25 DAH. After this date, slow fluctuations were maintained until the end of the experiment. Pepsin was firstly assayed 15 DAH related to gastric gland secretion and sharply increased 30 DAH. Then, it slowly varied until end of the experiment. Enzymes of brush border membranes, alkaline phosphatase and aminopeptidase N showed similar pattern on specific activities during the first 10 days. Thereafter, while specific activity of alkaline phosphatase slightly decreased 15 and fluctuated until 20 DAH, aminopeptidase N activity slowly increased 20 DAH. Then, activity of alkaline phosphatase and aminopeptidase N constantly increased 30 DAH, indicating maturation of the intestinal digestive process, and also, these activities continued to slowly increase until the end of the experiment. The specific activity of cytosolic peptidase, leucine–alanine peptidase, smoothly increased on day 8, then fluctuated until 15 DAH. After this date, in contrast to enzymes of brush border membranes, it sharply decreased 25 DAH and continued to gradually decline until the end of the experiment. These converse expressions were indicative of a maturation of enterocytes and the transition of an adult mode of digestion.     

Treatment Method Affects Color,Chemical, and Mineral Composition of Seabream (Sparus aurata) Fish Bone Powder from by-Products of Fish Fillet

ABSTRACT

Seabream fish bone powder was produced using different chemical methods and tap water. The effect of different chemical procedures (sodium hydroxide (NaOH); NaOH + citric acid; NaOH + sodium hypochlorite (NaOCl); NaOH + ethanol (EtOH); and NaOH + hydrogen chloride (HCl)) and tap water on proximate composition, yield, mineral composition, color, and sensorial odor was investigated. Despite its high bone powder yield (59.39%), tap water treatment was not an efficient method due to low calcium (Ca²⁺, 232.13 g/kg) and phosphorus (P, 111.63 g/kg) concentration and heavy fish odor. Sensorial odor analysis of seabream fish bone powder showed that tap water received the lowest scores (1.71/5), while chemically treated samples received sensorial odor scores higher than 4.00, with an average of 4.61, indicating that they had a very slight odor. The best fish bone powder yield was obtained using NaOH treatment (21.46%), where Ca²⁺ (276.73 g/kg) and P (147.23 g/kg) content was also high. The utilization of chemicals in combination with NaOH did not increase the sensorial odor score of seabream fish powders but resulted in a decrease in powder yield. Moreover, the mineral composition of all chemical processing techniques was comparable. Processing by-products of seabream fillet production with 8% NaOH will contribute to daily Ca²⁺ and P intake of individuals.     

Effects of stocking density on survival,growth and biochemical composition of cultured mussels (Mytilus galloprovincialis,Lamarck 1819) from an offshore submerged longline system

This study examined an offshore submerged mussel longline system, in the Black Sea, from May 2009 to May 2010. The system was allowed 1 year for spat collection. After a 1‐year spat collection period, some spat collectors were left untouched (NS), and some spat collectors were grazed and socked (S) for a grow‐out study in May 2009. The effects of stocking density on the growth and survival of the S and NS mussels were examined. The biochemical composition of the mussels was also determined. Environmental factors including temperature, salinity, chlorophyll a, total suspended matter, inorganic matter and organic matter were monitored monthly during the experimental period. In May 2010, the mean length and live weight of the S and NS mussels were 60.46 ± 0.60 mm and 53.34 ± 0.37 mm, respectively, and 20.50 ± 0.50 g and 13.11 ± 0.26 g respectively. Mean moisture and ash were 82.35 ± 0.47% and 6.67 ± 0.44% respectively. Mean carbohydrate, protein and lipid were 27.74 ± 2.40%, 57.68 ± 2.15% and 7.91 ± 0.68% respectively. These results indicate that a submerged offshore mussel culture system in the Black Sea can be commercially convenient. In addition, stock management via thinning out of the spat can considerably increase the marketable size of mussels, reduce harvest time and produce better growth.     

Effects of Natural and Artificial Colorants on Hot Smoked Garfish—Belone belone (Linnaeus, 1761)—Stored at 4 ± 1ºC

In this study, the effects of natural and artificial colorants on the shelf life of hot smoked garfish were investigated in terms of its chemical, microbiological, and sensory quality. Turmeric and Sunset Yellow FCF were used as the natural and artificial colorants, respectively. The amount of total volatile basic nitrogen (TVB-N) and thiobarbituric acid (TBA), counts of total mesophilic aerobic bacteria, total psychrophilic aerobic bacteria, total yeast and molds increased during the storage (p < 0.05). The results showed that turmeric and Sunset Yellow FCF had a significant effect on pH value and salt content of hot smoked garfish samples during storage (p < 0.05). According to the sensory analysis results, the shelf life of hot smoked garfish stored at 4 ± 1ºC was determined as 17 days.     

Impact of sublethal di‐n‐butyl phthalate on the aquaculture fish species Nile tilapia (Oreochromis niloticus): histopathology and oxidative stress assessment

Phthalates such as di‐n‐butyl phthalate (DBP) and their esters are widely used plasticizers, their ubiquitous presence in daily life, inevitably leads to their restricted use due to important environmental pollution and health impacts and endocrine disruption potential. The aim of this study was to examine the effects of a sublethal concentration of 10 mg L^?1 DBP on haematocrit (HCT) values, gills and liver histology, malondialdehyde (MDA, 2‐thiobarbituric acid‐TBA reactivity) and reduced glutathione (GSH) levels in gills and liver tissue as oxidative stress biomarkers in the aquaculture fish species Nile tilapia (Oreochromis niloticus) after 24 (DBP‐24) and 96 (DBP‐96) h exposure. No differences were found between per cent HCT values in the 24 h exposure groups (P > 0.05). Response of antioxidant defence systems in liver and gill tissues of the fish were dependent on exposure duration and changed to a higher extent during 96 h. MDA levels in liver tissue increased in DBP treated fish in comparison to the control fish. However, the differences between the exposure and control groups were not significant (P > 0.05). A statistically significant decrease (P > 0.05) was recorded in gill MDA levels in the DBP‐96 group when compared to the control and DBP‐24 groups. The liver GSH levels were unchanged in the DBP treated fish. However, GSH levels were significantly lower in the gill tissue of the DBP‐96 group. Exposure to DBP caused several degenerative changes in the histology of gill and liver tissue. Gills displayed hyperaemia, epithelial lifting, oedema, talengiectasia, epithelial hyperplasia and fusion of secondary lamellae, whereas in liver several circulatory anomalies (hyperaemia, blood congestion and sinosoid dilatation) and vacuolization of hepatocytes were observed. Histopathological results demonstrated that the gills were more affected than the liver perhaps due to their direct contact with DBP.     

Bleeding of anaesthetized and exhausted Atlantic salmon: body cavity inspection and residual blood in pre‐rigor and smoked fillets as determined by various analytical methods

The bleeding efficiency of anaesthetized and exhausted Atlantic salmon was studied. Unbled fish were used as control groups for both treatments. Several analytical methods (computer vision, Minolta Chroma Meter, transflectance spectroscopy, haemoglobin iron and visual assessment of smoked fillets) were used to evaluate colour or residual blood contents of pre‐rigor and smoked fillets. In all cases, the amount of residual blood in the fillets was modest and blood was not considered a quality problem in terms of fillet appearance. Perimortem stress did not affect residual blood contents of pre‐rigor fillets. Only salting and smoking had a significant effect on filet colour. The low levels of residual blood was partly attributed to filleting shortly after killing allowing washing before the blood had time to coagulate. In addition, a computer vision method was developed for automated blood inspection of the body cavity after gutting and washing. A classifier (‘no blood’ or ‘blood present’) based on linear discriminant analysis was tested and the classification accuracy was over 90% as evaluated with the leave‐one‐out method.