The present study is designed to assess the occurrence of a few organochlorine contaminants and their metabolites in eggs of different marine bird species in Iceland, a country located in the sub-Arctic of the North-Western Atlantic. Previous investigations from eg Sweden and The Netherlands have shown some obvious differences in contaminant concentrations, including eg hydroxylated polychlorinated biphenyl metabolites (OH-PCBs) in guillemot (Uria algae) and other bird species. Eggs from seven marine bird species, Arctic tern (Sterna paradisaea), common eider (Somateria mollissima), guillemot, fulmar (Fulmarus glacialis), great black-backed gull (Larus marinus), lesser black-backed gull (Larus fuscus), and great skua (Stercorarius skua), that all breed in Iceland, were collected and analyzed for several persistent organic compounds and their metabolites. The contaminant levels varied between the species investigated. The highest concentrations were found in eggs from the great skua (18 and 23 μg / g lw of CB-153 and 4,4′-DDE, respectively). The concentration difference was generally 2 orders of magnitude higher in great skua for all organochlorine compounds analyzed with the exception of HCB. HCB did not vary as much between the seven species (ranging from 34 to 710 ng / g lw). OH-PCB and MeSO2-PCB metabolites congener concentrations and patterns showed differences in metabolic capacity between bird species. Guillemot and great skua seem to distinguish themselves most from other species ie with the absence of 4-OH-CB187 and low relative levels of 4-OH-CB146 in guillemot and the low abundance of OH-PCBs in great skua.
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The influence of different salt concentrations of 6%, 15%, 18% and 24% (w / w) on mass transfer of water and salt during brine salting of cod loins was studied. An increase in salt concentration accelerated water exudation and salt diffusion in the cod loins. Weight gain of the cod loins increased with decreasing salt concentration and the cod loins in the 6% brine had the highest process yield. The salting kinetic parameter values for total and water weight changes decreased with increasing salt concentration. Inversely, higher salting kinetic parameter values for salt weight changes were observed for higher brine concentrations. The samples brined at 18% and 24% had identical effective diffusion coefficients and the highest effective diffusion value was found in the cod loins brined at 15%.
Aims: To study the effect of ova disinfection, antibiotic and microbial treatments on the dominant cultivable cod rearing microbiota at pre- and posthatch stages, determining some virulence-related phenotypic traits among bacterial isolates and their relation to larval survival.
Methods and Results: Sampling of rearing systems (rearing water, ova, larvae, feeds and supplement) for analysis of cultivable microbiota took place at early stages in 2004 and 2005. Cultivation, phenotypic and genotypic (16S rRNA gene) analyzes were performed. The production of putative virulence factors (PVFs), including haemolysin, siderophores and quorum-sensing signals, by bacterial isolates was investigated and related to larval survival. The study was performed during two spawning seasons, evaluating current hatchery practices (ova disinfection and antibiotic treatment of unhealthy larvae) and specific putative probiotics applied to ova and larvae or rotifers. A diversified microbiota (75 operational taxonomic units, OTUs) was observed in cod rearing systems influenced by the feeds and treatments, with prevailing γ-Proteobacteria prior to hatching towards a multiphyla microbiota posthatch. Phenotypic tests demonstrated the heterogeneity within some OTUs. Multivariate analysis of survival data in larval silos and the corresponding larval microbiota was used to divide the genotypic groups into beneficial / harmless and detrimental / opportunistic clusters. PVFs were common among the proposed detrimental / opportunistic OTUs.
Conclusions: The results clearly demonstrate the influence of exogenous feeding and treatments on larval gastrointestinal microbiota and the role of bacteria in larval survival.
Significance and Impact of the Study: Increased understanding of the microbiota in rearing systems may contribute to successful implementation of microbial management in cod aquaculture.
Purpose
The purpose of this paper is to investigate how the seafood industry perceives benefits of traceability implementation. Furthermore, ex ante cost ‐ benefit analyzes (CBAs) of adopting new traceability systems are conducted for two firms, operating at different steps of the seafood supply chains, to obtain preliminary knowledge on the net benefits of the project and on how costs and benefits are distributed among the actors .
Design / methodology / approach
This is a case ‐ based study.
Findings
The surveyed companies perceive improving supply chain management as the most important benefit of traceability. Other benefits are increase of the ability to retain existing customers; product quality improvement; product differentiation; and reduction of customer complaints. However, the quantifiable benefits are perceived differently by the actors at different steps in the supply chains, eg implementing radio frequency identification (RFID) tags on pallets in the seafood trading company case study shows tangibly quantifiable benefits.
Originality / value
The paper is useful for both practitioners and academics regarding perceived benefits of traceability in fish supply chains. The research provides initial insight into seafood companies' perspectives on the benefits of adopting RFID ‐ based traceability solutions. The paper suggests that the financial burden of implementing traceability may be borne by the processing firms, while gains are reaped by firms in the distribution business closer to the end consumer. This could provide a partial explanation as to why traceability has been slow to gain ground as a visible value ‐ adding marketing tool, and is mainly being driven by food safety regulations.
This article describes a consumer-based approach for development of new seafood product concepts among young adults in Norway and Iceland. The study aim was to gain insight into how young adults determine their acceptance of seafood and make potential product choices. Additional insights measured were confidence in seafood preparation and consumption choices when exposed to specific new seafood concepts. Based on consumer-reported values, three seafood product concepts were evaluated by 354 consumers in a web-based, joint experiment in Norway and Iceland. Consumers' evaluations showed a number of consumer preferences for specific seafood product concepts partly associated with and partly conflicting with their original values. Understanding consumer attitudes can help explain these results. The results of this study will be used as a guide for the next step in developing seafood product concepts.
The gelation properties of protein isolates extracted from tilapia muscle with acid and alkali-aided processing were compared to washed tilapia muscle. Gels were prepared with and without the addition of 2% NaCl (w / w) slightly above neutral pH and gelation properties and gel quality were determined using various procedures. Hardness and elasticity of gels as assessed by torsion testing was improved using 2% NaCl (w / w) compared to treatments without salt. Small strain oscillatory testing showed that storage modulus (G′) Of gel pastes prior to thermal gelation was significantly higher in the absence of salt, while smaller differences were seen after thermal gelation. Small strain oscillatory tests demonstrated a different gel forming mechanism for acid and alkali treated proteins compared to washed muscle. Fold tests demonstrated that acid treated proteins and washed muscle had significantly lower gel quality compared to alkali treated proteins. Addition of salt in gels improved gel water-holding capacity for acid and alkali treated proteins. Overall, the acid treated proteins exhibited poorer gelling ability compared to alkali treated proteins. Total content of SH groups was measured before and after gelation and S – S bonding did not explain the difference in gel forming ability of different treatments. The results indicate that the alkali-aided process can be used to produce high quality protein gels from tilapia muscle suitable for manufacturing of imitation seafood products.
Angel food cake was made using egg albumen subjected to the pH-induced unfolded and refolded treatment. The effect of treatment on the rheological properties of angel food cake was investigated. Egg albumen solutions were prepared and pH was adjusted to 1.5, 4.5, 8.5 or 12.5 and then held 60 min to unfold the proteins. After holding, the solutions were readjusted to pH 4.5 or 8.5, and held for 45 min to partially refold the proteins. Egg white foam with sucrose was whipped and flour and the rest of sucrose were folded into the foam. The foam batter was heated in a TA Instrument AR 2000 controlled stress rheometer equipped in a parallel geometry. Samples were heated from 21 ° C to 150 ° C at a rate of 8.5 ° C per min and then cooled down to 21 ° C to bake the angel food cake. At 21 ° C, oscillatory stress sweep was performed. There was no relationship between the G ′ value of angel cake batter and its G ′ value at 150 ° C. Changes in rheological properties of batters and angel food cakes using different combinations of ingredients were studied. The pH unfolding and refolding procedure led to more rigid final products compared to the controls with egg albumen samples not subject to pH treatment. Adding sucrose to the flour increased the starch gelation temperature up to 82 ° C. Higher protein concentrations resulted in better foams in the cake batter, but the batter made with an intermediate protein concentration produced the most rigid angel food cake. Adding egg albumin did not change gelation temperature of the starch. It appears that incorporation of flour with the egg white foam, leads to about a ten times decrease in the strength of the foam, and a decrease in the gelatinization process of starch after adding sugar, are crucial in forming an angel food cake texture.
The aim of this study was to use low-field nuclear magnetic resonance (NMR) and traditional chemical methods to investigate the physical and chemical differences in wild and farmed cod processed pre- and postrigor, and how these properties were affected by brine injection, brining , and freezing. In prerigor processed farmed or wild cod, brine injections followed by brining for 2 d, with brine concentrations up to 5.5% and 4%, respectively, were not sufficient to reach a muscle salt concentration of 2% as aimed for, while wild cod processed postrigor had sufficient salt uptake after the same processing. Low-field NMR provided valuable information about the differences in muscle structure between wild and farmed cod as well as the state of the water in the muscle during brine injection, brining, and during rigor tension. Low-field NMR is, therefore, a valuable tool that can be used to optimize the salting and storing processes of lightly salted cod products from both wild and farmed cod. For farmed cod to be used in the production of lightly salted products further research is needed.
Fish protein isolates (FPI) were extracted from haddock (Melanogrammus aeglefinus) cut-offs using the pH-shift method. Flow behavior and some functional properties of FPI containing 19% protein (pH 6.4) and different amounts of salt, sucrose and also polyphosphate stored 12 weeks at -18 ° C were studied. Additives influenced viscosity, but not flow behavior. Adding salt and sucrose increased water holding capacity (WHC), but significantly decreased viscosity (Brabender Unit) and whiteness. Using polyphosphate and sucrose did not affect WHC, and whiteness of FPI but it decreased viscosity. Different amounts of additives and frozen storage time changed functional attributes of FPI significantly. The results suggest
that the isolated proteins obtained through the pH-shift also need to be preserved against denaturation during frozen storage like surimi.
The production of heavy-salted cod (Bacalao) has changed from being a single-step process (kench) salting to a multistep procedure varying between producers and countries. Presalting by injection, brining, or pickling is increasingly applied prior to pile (dry) salting. This article describes the effects of different presalting methods (injection and brining, brining only, and pickling) on yield and chemical composition of salted cod fillets, in comparison to a single-kench salting step. The procedures used influenced the weight yields and chemical composition of the products. Injection was significantly different from other methods in increasing weight yields throughout brining, dry salting, and rehydration. The yield of nitrogenous compounds tended to be lower for injected and brine-salted fillets, mainly due to higher losses of nonprotein nitrogen.