Search Results (132)

This study evaluated the authenticity of olive oil in canned tuna products from the Slovenian market using both official methods, including fatty acid (FA) profiling, determination of the equivalent carbon number difference (ΔECN42), and sterol analysis, and an advanced method: stable carbon isotope analysis (δ¹³C) of FAs obtained through compound-specific isotope analysis (CSIA). Results from both methods confirmed that all 10 samples were authentic, as per the limits set by EU Regulation 2022/2104 and supported by the scientific literature. Method performance was further evaluated by adulterating the olive oil from the canned tuna with 5–20% vegetable oil (VO) or hazelnut oil (HO). While FA analysis struggled to differentiate adulterants with similar FA profiles, CSIA of FAs significantly improved detection. However, distinguishing between VO and HO blended samples remained challenging. PLS-DA analysis further supported the potential of using δ¹³C values of FA for food authentication. Storage of adulterated samples also influenced FA composition, leading to significant changes in MUFA/PUFA ratios and δ¹³C values, which became less negative, likely due to oxidative degradation. In summary, the combination of official and advanced methods, supported by chemometric analysis, offers a robust approach to ensuring the authenticity of olive oil in canned tuna. Full article

Skipjack tuna constitutes a crucial fishery resource in the Western and Central Pacific Ocean (WCPO) purse seine fishery, with high economic value and exploitation potential. It also serves as an essential subject for studying the interaction between fishery resource dynamics and marine ecosystems, as its resource abundance is significantly influenced by marine environmental factors. Skipjack tuna can be categorized into unassociated schools and associated schools, with the latter being predominant. Overfishing of the associated schools can adversely affect population health and the ecological environment. In-depth exploration of the spatial distribution responses of these two fish schools to environmental variables is significant for the rational development and utilization of tuna resources and for enhancing the sustainability of fishery resources. In sparsely sampled and complex marine environments, geographic similarity methods effectively predict tuna resources by quantifying local fishing ground environmental similarities. This study introduces geographical similarity theory. This study focused on 1° × 1° fishery data (2004–2021) released by the Western and Central Pacific Fisheries Commission (WCPFC) combined with relevant marine environmental data. We employed Geographical Convergent Cross Mapping (GCCM) to explore significant environmental factors influencing catch and variations in causal intensity and employed a Geographically Optimal Similarity (GOS) model to predict the spatial distribution of catch for the two types of tuna schools. The research findings indicate that the following: (1) Sea surface temperature (SST), sea surface salinity (SSS), and net primary productivity (NPP) are key factors in GCCM model analysis, significantly influencing the catch of two fish schools. (2) The GOS model exhibits higher prediction accuracy and stability compared to the Generalized Additive Model (GAM) and the Basic Configuration Similarity (BCS) model. R² values reaching 0.656 and 0.649 for the two types of schools, respectively, suggest that the geographical similarity method has certain applicability and application potential in the spatial prediction of fishery resources. (3) Uncertainty analysis revealed more stable predictions for unassociated schools, with 72.65% of the results falling within the low-uncertainty range (0.00–0.25), compared to 52.65% for associated schools. This study, based on geographical similarity theory, elucidates differential spatial responses of distinct schools to environmental factors and provides a novel approach for fishing ground prediction. It also provides a scientific basis for the dynamic assessment and rational exploitation and utilization of skipjack tuna resources in the Pacific Ocean. Full article

Parasitic diseases can be a significant constraint on aquaculture industries, which continue to develop in response to the rise in global demand for sustainable protein sources. Blood flukes, Cardicola forsteri and Cardicola orientalis, are economically significant parasites of Southern bluefin tuna (Australia), Pacific bluefin tuna (Japan), and Atlantic bluefin tuna (Mediterranean) as they are responsible for blood vessel obstruction in the gills leading to branchitis and mortalities when untreated. Here, we have defined the mitochondrial genomes for these species—the first for any aporocotylids. Oxford nanopore long-read sequencing was used to sequence C. orientalis from a single individual. The mitochondrial genome of C. forsteri was assembled and curated from available sequence data. Both Cardicola spp. mitogenomes contained 12 protein coding, 2 ribosomal and 22 tRNA genes, with the gene order matching that of Asian schistosomes. A control region was identified for each species which contained long and short repeats; the region for C. forsteri was longest, and the overall pattern differed between the two species. A surprisingly high nucleotide diversity was observed between the two species, generating interest into the mitochondrial genes of related species. This paper provides a useful resource for future genetics-based research of aporocotylids and other flatworm parasites of socioeconomic significance. Full article

A two-factorial experiment was conducted to evaluate the potential for improving the palatability and utilization of tuna by-product meal (TBM) as a replacement for fish meal (FM) via supplementing the diet of juvenile greater amberjack (Seriola dumerili) with powdered salmon roe liquid (PSRL). FM protein in the control diet (C) was partially replaced with TBM at levels of 25% (T25R0) and 40% (T40R0). PSRL was then added at 5% and 10% to both the T25R0 and T40R0 diets, resulting in the formulations T25R5, T25R10, T40R5, and T40R10. After a 6-week rearing period, during which groups of 30 juveniles (mean initial weight of approximately 1.7 g) were stocked in 500 L tanks, there were no significant differences in the final mean weight, weight gain, or specific growth rate among fish fed diets C, T25R0, and T25R5. However, the other experimental diets showed significantly lower values compared to the C diet (p < 0.05). PSRL supplementation did not significantly enhance either palatability or feeding rate in TBM-based diets (p > 0.05). Two-way ANOVA indicated that only FM replacement with TBM had a significant effect on the growth parameters mentioned above (p < 0.05). A significantly lower whole-body crude lipid content was observed in all test diets compared to that in the C diet, resulting in significantly lower lipid retention efficiency in all test groups except T25R5 and T25R10 (p < 0.05). These results suggest that 25% of FM protein can be replaced with TBM protein in the diet of juvenile greater amberjack, but PSRL does not effectively address the palatability issues associated with TBM-based diets. Full article

An investigation of the histamine presence in canned fish is crucial in terms of food safety and human health. The aim of this study was to investigate the levels of histamine, pH, and salt in various canned fish products consumed in Ankara, Türkiye. For this purpose, a total of 80 canned food samples (30 tuna, 30 sardine, and 20 anchovy samples) from different firms were analyzed for histamines using an enzyme-linked immunosorbent assay technique. In 33 (41.25%) out of 80 food samples, histamine was detected in concentrations ranging between 2.51 mg/kg and 20.97 mg/kg. The mean histamine levels (±SE) of the canned tuna, sardine, and anchovy samples were found to be 7.05 ± 1.07 mg/kg, 4.09 ± 0.32 mg/kg, and 4.67 ± 0.58 mg/kg, respectively. The mean pH levels (±SE) of the canned tuna, sardine, and anchovy samples were found to be 5.91 ± 0.009, 6.32 ± 0.02, and 5.99 ± 0.04, respectively. At the same time, the mean salt levels (±SE) of the canned tuna, sardine, and anchovy samples were found to be 1.18 ± 0.03%, 1.80 ± 0.09%, and 1.91 ± 0.09%, respectively. Our data reveal that the histamine levels found in all the samples were within the Turkish Food Codex values. In addition, the mean values of pH and salt found in the canned fish samples were within the Turkish Standard Institute values. Full article

Background/Objectives: Calcitriol, the active form of vitamin D, has a broad physiological effect, and its deficiency has been identified as a risk factor for many diseases. This study aimed to analyze the dietary intake of vitamin D and the factors determining its intake among Polish post-primary school students. The data obtained were then related to the dietary recommendations for the Polish population. Methods: The study was conducted on a nationwide sample of 3257 male adolescents (aged 14–20 years) recruited from all macroregions of Poland. Dietary vitamin D intake (dVDi) was assessed using the Vitamin D Estimation Only–Food Frequency Questionnaire (VIDEO-FFQ). Results: The median dietary intake of vitamin D was 4.36 µg daily. This value was below the recommended intake of 15 µg of vitamin D, according to Polish standards, in almost 80% of the study group. The observed dietary vitamin D intake bellow the recommended level ranged from 35.5% of students attending schools in the North-Western macroregion to 93.7% in the Central macroregion, from 45.4% of students attending schools located in the countryside to 92.7% in big cities, from 85.3% among underweight students to 76.7% of obese students, over 77% in both age groups (14–17 and 18–20 years old), and over 78% in both groups: supplementing and not supplementing vitamin D. Fish and fish products provided the highest vitamin D (38.7%), while cereal products and fats provided the lowest (4.49% and 4.35%, respectively). The highest amounts of vitamin D were provided by salmon, rainbow trout, herring, and eel (fish species containing 7–15 µg of vitamin D in 100 g of product), and halibut, mackerel, brook trout, sole, and tuna (fish species containing 1.05–4 µg of vitamin D in 100 g of product), and these fish were consumed in the largest quantities by male adolescents. Dietary vitamin D intake was notably higher in adolescents from the North-Western macroregion of Poland (median: 50.57 vs. 3.72–5.18 µg daily for other macroregions), those attending schools in the countryside (median: 49.49 vs. 3.97–4.39 µg daily for other locations of the school), those with a normal body weight (median: 4.59 vs. 3.38 µg daily for adolescents with underweight), and those who took vitamin D supplements (median: 4.71 vs. 4.06 µg daily for adolescents not supplemented with vitamin D). However, the results showed that dVDi was not dependent on age. Conclusions: The study results indicate that low dVDi among Polish male adolescents can be attributed to the limited supply of vitamin D from dietary sources, especially fish and fish products. The necessity for interventions has been identified, including nutritional education on the role of vitamin D and its sources in the diet. Full article

Language is that kind of expression by which effective communication with another can be well expressed. One may consider such as a connecting bridge for bridging communication gaps for the hearing- and speech-impaired, even though it remains as an advanced method for hand gesture expression along with identification through the various different unidentified signals to configure their palms. This challenge can be met with a novel Enhanced Convolutional Transformer with Adaptive Tuna Swarm Optimization (ECT-ATSO) recognition framework proposed for double-handed sign language. In order to improve both model generalization and image quality, preprocessing is applied to images prior to prediction, and the proposed dataset is organized to handle multiple dynamic words. Feature graining is employed to obtain local features, and the ViT transformer architecture is then utilized to capture global features from the preprocessed images. After concatenation, this generates a feature map that is then divided into various words using an Inverted Residual Feed-Forward Network (IRFFN). Using the Tuna Swarm Optimization (TSO) algorithm in its enhanced form, the provided Enhanced Convolutional Transformer (ECT) model is optimally tuned to handle the problem dimensions with convergence problem parameters. In order to solve local optimization constraints when adjusting the position for the tuna update process, a mutation operator was introduced. The dataset visualization that demonstrates the best effectiveness compared to alternative cutting-edge methods, recognition accuracy, and convergences serves as a means to measure performance of this suggested framework. Full article

Canning is an excellent solution to provide convenient, affordable, nutritious, and safe seafood with a long shelf life. However, many canned products use tuna, sardines, and Atlantic chub mackerel, species that raise sustainability concerns and whose overuse can put additional pressure on them. Hence, this study aimed to i) develop and assess a nutritious and sustainable canned meal prototype using the Atlantic horse mackerel (Trachurus trachurus) (whose EU allowable-catch amounts have increased, particularly, in Iberian waters) and vegetables in light brine in terms of stability, sterility, and physicochemical and sensory properties over a 4-month period at room temperature and ii) evaluate its nutritional contribution for different population groups. After preparation, the meal was stored for one month at ≈20 °C and ≈40 °C (to simulate the 4 months). Although the pH was not stable, the meal was considered commercially sterile according to the challenge accelerated tests. Moreover, aging did not significantly affect the meal’s physicochemical and sensory properties. This innovative meal prototype can be claimed to be “low-fat”, “reduced in NaCl/Na”, a “source of protein, phosphorus, iron, selenium and vitamin D”, and “high in vitamin B12”. It proved to be both nutritious and appealing for consumption, with potential to be scaled up. Full article

Mercury (Hg) is a global health concern due to its prevalence, persistence, and toxicity. Numerous studies have assessed Hg concentrations in seafood, but variability in reported concentrations highlights the need for continued monitoring and stricter regulations. We measured total Hg (tHg) in 148 pre-processed, packaged seafood products purchased in Raleigh, North Carolina, using thermal decomposition–gold amalgamation atomic absorption spectrophotometry. Products were grouped into three categories based on trophic ecology and physiology: (1) tuna, (2) other bony fish, and (3) shellfish and squid. Among tuna, albacore had the highest average tHg (396.4 ng/g ± 172.1), while yellowfin had the lowest (68.3 ng/g ± 64.7). Herring (54.0 ng/g ± 23.2) and crab (78.2 ng/g ± 24.1) had the highest concentrations in the other two groups. One can of albacore exceeded the FDA action level of 1 part per million (1.3 ppm or 1300 ng/g). Brand differences were significant for both albacore and light tuna, with Brand 1 consistently showing higher Hg levels. Comparisons to FDA data (1990–2012) suggest Hg concentrations in tuna have remained stable over the past two decades. This study underscores the variability of Hg concentrations across species and brands and the need for continued monitoring to protect consumers. Full article

Multifunctional self-healing supramolecular structural toughened resins, formulated to counteract the insulating properties of epoxy polymers and integrating auto-repair mechanisms, are morphologically and spectroscopically characterized using Tunneling Atomic Force Microscopy (TUNA) and Fourier transform infrared spectroscopy (FT-IR), respectively. Specifically, the multifunctional resin comprises self-healing molecular fillers and electrically conductive carbon nanotubes (CNTs) embedded in the matrix. The selected self-healing molecules can form non-covalent bonds with the hydroxyl (OH) and carbonyl (C=O) groups of the toughened epoxy matrix through their H-bonding donor and acceptor sites. An FT-IR analysis has been conducted to evaluate the interactions that the barbiturate acid derivatives, serving as self-healing fillers, can form with the constituent parts of the toughened epoxy blend. Tunneling Atomic Force Microscopy (TUNA) highlights the morphological characteristics of CNTs, their dispersion within the polymeric matrix, and their affinity for the globular rubber domains. The TUNA technique maps the samples’ electrical conductivity at micro- and nanoscale spatial domains. Detecting electrical currents reveals supramolecular networks, determined by hydrogen bonds, within the samples, showcasing the morphological features of the sample containing an embedded conductive nanofiller in the hosting matrix. Full article

The existing in vitro and clinical trial evidence supports the health and wellness benefits of collagen peptides sourced from various origins. Despite this, research on collagen peptides from tuna remains limited. Notably, tuna-derived peptides possess an inherent fishy odor, rendering them unsuitable for direct application in humans. This study explores the enhancement of tuna peptides’ applicability in cosmetics through odor mitigation. We developed a dual-phase ozone treatment, employing both dry and wet ozone, to deodorize tuna peptide powder, enabling its use in cosmetic formulations. The deodorized tuna peptide powder can be used in cosmetics. We optimized the ozone nitrification and deodorization conditions for tuna peptide powder by adjusting the treatment time, ozone concentration, and temperature. Sensory evaluation and GC-MS analysis confirmed the effectiveness of fishy odor removal, offering a comprehensive understanding of the deodorization process. The findings reveal that wet ozonation at 50 °C with an ozone concentration of 99.1 mg/L for 40 min significantly reduces the fishy odor of tuna peptide powder. Notably, n-Hexaldehyde, the primary odor-contributing volatile compound, decreased by 66.5%, confirming the efficacy of ozone treatment in odor mitigation. Moreover, the protein activity within the powder remained unaffected, ensuring the preservation of its functional properties. This study demonstrates the efficacy of ozone oxidation in adapting tuna peptide powder for cosmetic use. Full article

Environmental temperature declines significantly impact the physiological processes of marine organisms, particularly under the cool La Nina conditions, challenging yellowfin tuna (Thunnus albacares) aquaculture. Low temperatures affect fish metabolism and immune functions and can alter the gut microbiota composition, influencing health and growth. This study investigates the impact of low temperatures on the gut microbiota of juvenile yellowfin tuna. Fish were divided into a Low Temperature (LT) group (24 °C), an Ultra Low Temperature (ULT) group (18 °C), and a Control group (CG) (30 °C), with evaluations at 0, 12, 24, and 36 h using α-diversity analysis and microbial species composition. Results indicated a significant increase in the Ace index for the ULT group after 36 h of cold stress (p < 0.05), with no significant changes in the Shannon index. A decline in Proteobacteria and increases in Verrucomicrobiota and Firmicutes were observed in both LT and ULT groups. Additionally, both LT and ULT groups showed a significant rise in the Ace index at 36 h (p < 0.05), with a significant decrease in the Shannon index in the ULT group at 24 h. Furthermore, Firmicutes significantly increased at 12 h in both temperature groups (p < 0.05). These findings highlight the potential role of the gut microbiome in adapting yellowfin tuna to cold environments and provide microbial insights into their physiological adaptations, laying a foundation for further research and practical applications in aquaculture under cold conditions. Full article

Fish sustainability has become an ever more important issue in recent years, as increases in consumption are leading to overfishing practices, resulting in the depletion of the seas and environmental damage. Therefore, fish companies have been adhering to sustainability programs, although these sustainable practices are not well valued and thus well known by end consumers. Therefore, this study aimed to assess the impact of sustainability label information on the hedonic perception of a consumer group regarding two fish species threatened by overfishing: European anchovy (Engraulis encrasicolus) and Bluefin tuna (Thunnus thynnus). The approach used was a blind–expected–informed evaluation. The results showed a positive perception of the species with the sustainability label by recording higher informed hedonic scores than blind ones. Thus, in conclusion, fish sustainability positively influenced the consumers, increasing their liking scores from the blind to the informed session. This study can expand previous knowledge on environmental sustainability, especially fisheries sustainability, and understand the relationships between sustainability eco-labels and consumer behaviour. Full article

An increasing trend among food business operators (FBOs) to extend the shelf life of Ready-To-Eat (RTE) fish products over 5 days, the duration usually assigned to this kind of product, has been observed recently. In this study, three independent challenge tests (food artificial contamination) were performed on tuna fillet, marinated salmon tartare, and cubed salmon, with the aim of calculating the maximum growth rate (V_max) of Listeria monocytogenes and estimating the time required to reach the legal limit of 2 log CFU/g, as established by European Regulation 2073/2005. The pathogen counts were fitted by the model of Baranyi and Roberts to calculate the V_max, which were 0.041, 0.020, and 0.039 log CFU/g·h⁻¹, respectively, for the tuna fillet, marinated salmon tartare, and cubed salmon at 10 °C. These results can help FBOs in assigning the correct shelf life based on hygienic practices during the process, product characteristics, and storage conditions. The time to reach the legal limit greatly depends on the starting concentration of the pathogen and on the storage temperature. The challenges for FBOs and the health authorities include reducing the contamination of L. monocytogenes, controlling the retail temperatures, and implementing the analytical tests for quick responses. Full article

Wire-driven robotic fish can effectively simulate the movement of real fish, but research on high-frequency wire-driven robotic fish is limited. This paper introduces the development of wire-driven robotic fish based on a double-sine mechanism. The appearance of the fish body is designed based on the morphology of tuna, and a mechanism that can support the high-frequency movement of the wire-driven mechanism is designed. The swimming speed and turning performance of the robotic fish are experimentally tested at various swing frequencies. The experimental results show that within the range of 1 to 4 Hz, the swimming speed of the robotic fish with different tail stiffness increases as the frequency increases. However, when the frequency exceeds 4 Hz, the swimming speed decreases. The tail joint with lower stiffness performs better at low frequencies, but as frequency increases, higher stiffness results in better swimming performance. Experimental tests show that the turning radius increases with higher swing frequencies and lower stiffness, resulting in a larger turning radius. This experiment will help to improve the application of high-frequency wire-driven mechanisms in the study of robot fish movement and carry out more in-depth bionic research in the future. Full article