Search Results (27)

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

Aquafeed production is a fast-growing industry, seeking novel, cost-efficient raw materials to diversify traditional ingredients like fish meal and oil. Insects, particularly BSF larvae, convert by-products and waste into value-added biomass. In this study, by-products and co-products from two major fish-transforming industries in the Iberian Peninsula, i.e., tuna heads (THs) and codfish frames (CFs), hydrolysates of THs and CFs, and TH oils, were supplied to BSF larvae to improve their profile in n-3 fatty acids (FAs), namely EPA and DHA, and their protein/amino acid content. By testing the replacement levels of a control diet with by-products and co-products, we evaluated the amount of n-3 FA that could be added to BSF larval tissues. The results showed that high levels of a hydrolysed diet negatively impacted larval survival. In addition, parameters such as the moisture, protein content, and viscosity of the substrate affected bioconversion rates. Nevertheless, BSF fed with these diets contained high levels of lysine (5.8–8.4%, dry weight (DW)), methionine (1.5–2.4%, DW), and n-3 FA (14.4% DW: EPA 6.7% and DHA 7.1%). These findings suggest that BSF can effectively convert fish by-products into a nutrient-rich biomass for aquafeeds, supporting the diversification of raw material sources and promoting a circular bioeconomy. Full article

The global tuna canning industry generates substantial volumes of by-products, comprising 50% to 70% of the total processed material. Traditionally, these by-products have been utilized in low-value products such as fish oils and fishmeal. However, there is significant potential to extract high-value compounds from these by-products, such as calcium phosphates (CaP), which can have pharmaceutical, agricultural and biotechnological applications. This work explores the potential of tuna canning by-products, particularly mineral-rich fractions (central skeleton, head and fish bones) as sources of calcium phosphates (CaP), offering a sustainable alternative to conventional synthetic derivatives within a circular bioeconomy framework. By-products from two of the most exploited species (yellowfin and skipjack) were subjected to enzymatic hydrolysis and chemical extraction, followed by controlled calcination to obtain CaP. The content of organic matter, nitrogen, total proteins, lipids and amino acids in the cleaned bones, as well as the main chemical bonds, structure and elemental composition (FT-Raman, XRD, XRF) were evaluated. Results indicated that the highest recovery yield of wet bones was achieved using the chemical method, particularly from the dorsal and caudal fins of yellowfin tuna. The proximal composition, with ash content ranging from 52% to 66% and protein content varying between 30% and 53%, highlights the potential of tuna skeleton substrates for plant growth formulations. Furthermore, variations in crystalline structures of the substrates revealed significant differences depending on the by-product source and species. XRD and Raman results confirmed a monophase calcium phosphate composition in most samples from both species, primarily based on hydroxyapatite (central skeleton, caudal and dorsal fin) or whitlockite/β-tricalcium phosphate (viscera), whereas the heads exhibited a biphasic composition. Comparing the species, yellowfin tuna (YF) exhibited a hydroxyapatite structure in the branchial arch and scales, while skipjack (SKJ) had a biphasic composition in these same regions. Full article

With the increase in global aquaculture production, managing waste from aquatic biomass has become a significant concern. This research aimed to develop a sustainable valorization approach for recovering calcium-rich fish, including mackerel tuna and pangas bone and shrimp shell powders. The powders were characterized by various physicochemical and nutritional parameters, including proximate composition, amino acids, protein solubility, water holding capacity (WHC), oil holding capacity (OHC), and heavy metal contents. Color analysis and structural examination were carried out using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FT-IR), and in vitro radical scavenging activity was assessed. Significant protein content was observed in the powders, which was highest in shrimp shell powder (SSP) at 37.78%, followed by 32.29% in pangas bone powder (PBP) and 30.28% in tuna bone powder (TBP). The ash content was consistent in PBP and TBP at around 62.80%, while SSP had a lower ash content of 36.58%. Amino acid analysis detected 14 different amino acids in the recovered powders. Notably, SSP demonstrated the highest WHC and OHC values (2.90 and 2.81, respectively), whereas TBP exhibited the lowest values (1.11 for WHC and 1.21 for OHC). FE-SEM revealed the compact structure of TBP and PBP, contrasting with the porous surface of SSP. EDX analysis indicated higher calcium (24.52%) and phosphorus (13.85%) contents in TBP, while SSP was enriched in carbon (54.54%). All detected heavy metal concentrations were within acceptable limits. The recovered powders demonstrated significant ABTS free radical scavenging activity. The findings of this study suggest the suitability of the recovered powders for various food and pharmaceutical applications. Full article

To increase the value of the by-products of the canned tuna industry, the memory enhancement effect and the possible mechanisms of omega-3-rich tuna oil in bilateral ovariectomized (OVX) rats were assessed. Female rats were orally given tuna oil at doses of 140, 200, and 250 mg/kg of body weight (BW) for 28 days before OVX and for 21 days continually after OVX. Memory performance was assessed every week, whereas the parameters regarding mechanisms of action were assessed at the end of the study. All doses of tuna oil enhanced memory, docosahexaenoic acid (DHA) levels, and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities but decreased cortisol, acetylcholinesterase (AChE), malondialdehyde (MDA), and inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Medium and high doses of tuna oil suppressed monoamine oxidase (MAO) but increased eNOS activity. A high dose of tuna oil suppressed gamma-aminotransferase (GABA-T) but increased glutamic acid decarboxylase (GAD) and sirtuin-1. A medium dose of tuna oil decreased homocysteine (Hcys) and C-reactive protein. No change in telomere or estradiol was observed in this study. Our results suggest the memory-enhancing effect of tuna oil in an OVX rat model of menopause. The main mechanisms may involve a reduction in oxidative stress, inflammation, and neurotransmitter regulation. Full article

The market for fish oil supplements is growing significantly, as fish oil is one of the best-known sources of beneficial long-chain polyunsaturated fatty acids. However, along with the potent health benefits, first of all regarding the reduction of cardiovascular disease risk, the consumption of fish oil could also pose a potential health risk. Namely, fish positioned higher in the food chain, such as shark, swordfish, tuna, mackerel, etc., are known to bioaccumulate mercury. Indeed, consumption of fish is the main source of mercury exposure for humans, specifically of the most toxic form of mercury, methylmercury (MeHg). In the human organism, MeHg manifests a wide spectrum of adverse health effects, collectively known as Minamata disease. The objective of this study was to assess the health risk of mercury exposure through fish oil supplement consumption. The total mercury content of 42 fish oil supplements available on the markets of the Republic of Serbia and the Republic of Srpska was determined by a direct mercury analyzer. A risk assessment was conducted for the adult population, taking into account the recommended intake of supplements and the toxicological profile of MeHg: an oral reference dose (RfD) of 0.0001 mg/kg bw/day and a tolerable weekly intake (TWI) of 0.0013 mg/kg bw. Since MeHg accounts for up to 75–98% of the total mercury content in fish, the precautionary principle was applied, meaning that the total mercury content was considered equal to MeHg. The total mercury content in supplements ranged from 0.001 to 0.0057 mg/kg, which is far below the maximum level for food supplements of 0.1 mg/kg. The mean (±standard deviation) of mercury content was 0.0019 ± 0.0009 mg/kg. The corresponding consumer mean exposure was 0.042 ± 0.039% of the RfD, with a maximum at 0.24%, and in the case of TWI, 0.023 ± 0.021%, with a maximum at 0.13%. Thus, the risk from mercury in fish oil supplements was negligible, even for pregnant and nursing women who need to protect their children from the extremely harmful developmental neurotoxicity of MeHg. However, the presence of other lipophilic environmental pollutants, such as polychlorinated biphenyls, dibenzodioxins, and dibenzofurans, should be investigated. Full article

With the current consumer interest in health and wellbeing, the market growth potential for long-chain polyunsaturated fatty acid (PUFA) supplements is greater than ever before. Fish oil (anchovy, mackerel, herring, sardines, tuna, salmon, cod, krill, etc.) is a concentrated source of beneficial PUFA for dietary supplements, with eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid attracting the most attention due to their capacity to boost human heart and brain health and strengthen the immune system. This study aimed to assess the profile and intake of PUFA from fish oil food supplements. The fatty acid profiles of 42 fish oil supplements collected from the markets of the Republic of Serbia and the Republic of Srpska were obtained using GC-FID analysis. The intake of PUFA in the adult population was assessed by taking into account labeled daily doses of supplements and recommendation for an EPA+DHA daily intake of 250 mg. The mean (range) percentage contributions of EPA and DHA in total fish oil fatty acids were 24.6 ± 11.3% (5.5–57.6%) and 21.4 ± 14.9% (3.3–72.3%), respectively. The maximum EPA concentration was determined in a supplement acquired in a sport supplements store, while in the case of DHA, a supplement with a “premium” label took the leading position. On the other hand, the lowest levels were recorded in fish pearls and a supplement containing a mixture of fish, flax, and borage oils, the only one containing alpha-linolenic acid (ALA). The means and ranges of EPA+DHA intake corresponding to the minimum and maximum labeled doses were 202.1 ± 120.3% (1.1–577.6%) and 263.2 ± 147.3% (1.1–749.7%) of the daily recommended amount, respectively. Such intakes do not raise safety concerns for the general population. While the health benefits associated with PUFA intake are potent, the concerns over sustainability and risk of oceanic pollution cannot be neglected, especially in relation to potential contamination with methylmercury, one of the main reasons why great care is recommended for pregnant and lactating women (recommended additional DHA intake 100–200 mg/day) regarding the consumption of fish and fish products. Full article

Human milk lipids generally have the maximum long-chain fatty acids at the sn-2 position of the glycerol backbone. This positioning makes them more digestible than long-chain fatty acids located at the sn-1, 3 positions. These unique fatty acid distributions are not found elsewhere in nature. When lactation is insufficient, infant formula milk has been used as a substitute. However, the distribution of most fatty acids ininfant formula milk is still different from human milk. Therefore, structured lipids were produced by the redistribution of medium-chain fatty acids from commercial butterfat (CBF) and n-3 and n-6 long-chain fatty acids from skipjack tuna eyeball oil (STEO). Redistribution was carried out via transesterification facilitated by Asian seabass liver lipase (ASL-L). Under the optimum conditions including a CBF/STEO ratio (3:1), transesterification time (60 h), and ASL-L unit (250 U), the newly formed modified-STEO (M-STEO) contained 93.56% triacylglycerol (TAG), 0.31% diacylglycerol (DAG), and 0.02% monoacylglycerol (MAG). The incorporated medium-chain fatty acids accounted for 18.2% of M-STEO, whereas ASL-L could incorporate 40% of n-3 fatty acids and 25–30% palmitic acid in M-STEO. The ¹H NMRA and ¹³CNMR results revealed that the major saturated fatty acid (palmitic acid) and unsaturated fatty acids (DHA and EPA) were distributed at the sn-2 position of the TAGs in M-STEO. Thus, M-STEO enriched with medium-chain fatty acids and n-3 fatty acids positioned at the sn-2 position of TAGs can be a potential substitute for human milk fatty acids in infant formula milk (IFM). Full article

Background: Fish oil is one of the most common lipidic substances that is consumed as a dietary supplement. The high omega-3 fatty acid content in fish oil is responsible for its numerous health benefits. Fish species such as mackerel, herring, tuna, and salmon are particularly rich in these lipids, which contain two essential omega-3 fatty acids, known as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Objectives: Due to the scarcity of information in the literature, this study aimed to conduct a qualitative and quantitative characterization of triglycerides (TAGs) in crude tuna fish oil using HPLC/HRMS. Fatty acid (FA) determination was also performed using GC/MS. The tuna fish oils analyzed were produced using a green, low-temperature process from the remnants of fish production, avoiding the use of any extraction solvents. Results: The analyses led to the tentative identification and semi-quantitation of 81 TAGs. In silico saponification and comparison with fatty acid methyl ester results helped to confirm the identified TAGs and their quantities. The study found that the produced oil is rich in EPA, DHA, and erucic acid, while the negligible isomerization of fatty acids to trans-derivatives was observed. Full article

Among biogenic amines, histamine is most frequently involved in foodborne intoxication. To evaluate histamine formation in tuna, several storage conditions were reproduced. An LC-MS/MS method was used for analytical determinations. Fresh tuna samples (not contaminated and grafted with tuna muscle naturally incurred with histamine at 6000 mg/kg) were stored at 4, 12, and 20 °C, and daily samples were collected for 6 days. The development of histamine was observed only in grafted tuna samples. At 4 °C, histamine formation progressed from 12.8 mg/kg (day 1) up to 68.2 mg/kg (day 6). At 12 °C, higher concentrations developed (23.9 mg/kg on day 1 up to 2721.3 mg/kg on day 6) relative to 20 °C (from 12.0 to 1681.0 mg/kg). It was found that at 4 °C, if grafted tuna was submerged in oil, histamine formation progressed more slowly. In a naturally contaminated sample, it was observed that the histamine distribution was uniform, while the normal cooking process did not affect the histamine level. Furthermore, it was found that the use of histamine-contaminated equipment for food handling may result in histamine formation in food. These results confirm the importance of implementing good hygiene practices and respecting the cold chain. Full article

Recently Camelina sativa, has been genetically modified to produce oils rich in omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA), EPA (eicosapentaenoic acid) and EPA + DHA (docosahexaenoic acid). The aim of this study was to test the feasibility of using these novel sources of de novo EPA and EPA + DHA as substitutes for marine oil in feeds for juvenile Atlantic Bluefin tuna (ABT). The results showed the oils were practical sources of n-3 LC-PUFA which could potentially replace fish oil (FO) in feeds for ABT juveniles. Fish fed the test diets (ECO, EPA alone and DCO, EPA + DHA) displayed good growth performance, survival and feed utilisation approaching that of ABT fed the reference diet (MGK) containing marine fish oil with the rank order being MGK > DCO > ECO. The test diets showed positive effects, upregulating the expression of genes of major nuclear receptors and those of lipid metabolism including digestion, LC-PUFA synthesis and antioxidant pathways. The results indicated that the DCO feed containing both DHA and EPA performed better than the ECO feed with much lower DHA. However, feeds formulated with both these oils may still require supplementary DHA to satisfy the high requirement of ABT for this essential nutrient. Full article

Lipase hydrolysis is an effective method to develop different functional types of lipids. In this study, tuna oil was partially hydrolyzed at 30% and 60% by Thermomyces lanuginosus lipase (TL 100 L) and Candida Antarctica lipase A (ADL), respectively, to obtain lipid-modified acylglycerols. The lipidomic profiling of the acylglycerols was investigated by UPLC-Q-TOF-MS and GC–MS to clarify the lipid modification effect of these two lipases on tuna oil. The results showed that 247 kinds of acylglycerols and 23 kinds of fatty acids were identified in the five samples. In the ADL group, the content of triacylglycerols (TAG) and diacylglycerols (DAG) increased by 4.93% and 114.38%, respectively, with an increase in the hydrolysis degree (HD), while there was a decreasing trend in the TL 100 L group. TL 100 L had a better enrichment effect on DHA, while ADL was more inclined to enrich EPA and hydrolyze saturated fatty acids. Cluster analysis showed that the lipids obtained by the hydrolysis of TL 100 L and ADL were significantly different in the cluster analysis of TAG, DAG, and monoacylglycerols (MAG). TL 100 L has strong TAG selectivity and a strong ability to hydrolyze acylglycerols, while ADL has the potential to synthesize functional lipids containing omega-3 PUFAs, especially DAG. Full article

Long-chain (LC) n-3 polyunsaturated fatty acids (PUFAs) have drawn attention in the field of neuropsychiatric disorders, in particular depression. However, whether dietary supplementation with LC n-3 PUFA protects from the development of mood disorders is still a matter of debate. In the present study, we studied the effect of a two-month exposure to isocaloric diets containing n-3 PUFAs in the form of relatively short-chain (SC) (6% of rapeseed oil, enriched in α-linolenic acid (ALA)) or LC (6% of tuna oil, enriched in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) PUFAs on behavior and synaptic plasticity of mice submitted or not to a chronic social defeat stress (CSDS), previously reported to alter emotional and social behavior, as well as synaptic plasticity in the nucleus accumbens (NAc). First, fatty acid content and lipid metabolism gene expression were measured in the NAc of mice fed a SC (control) or LC n-3 (supplemented) PUFA diet. Our results indicate that LC n-3 supplementation significantly increased some n-3 PUFAs, while decreasing some n-6 PUFAs. Then, in another cohort, control and n-3 PUFA-supplemented mice were subjected to CSDS, and social and emotional behaviors were assessed, together with long-term depression plasticity in accumbal medium spiny neurons. Overall, mice fed with n-3 PUFA supplementation displayed an emotional behavior profile and electrophysiological properties of medium spiny neurons which was distinct from the ones displayed by mice fed with the control diet, and this, independently of CSDS. Using the social interaction index to discriminate resilient and susceptible mice in the CSDS groups, n-3 supplementation promoted resiliency. Altogether, our results pinpoint that exposure to a diet rich in LC n-3 PUFA, as compared to a diet rich in SC n-3 PUFA, influences the NAc fatty acid profile. In addition, electrophysiological properties and emotional behavior were altered in LC n-3 PUFA mice, independently of CSDS. Our results bring new insights about the effect of LC n-3 PUFA on emotional behavior and synaptic plasticity. Full article

The valorization of side streams from fishery and aquaculture value-chains is a valuable solution to address one of the challenges of the circular economy: turning wastes into profit. Side streams produced after filleting of sea cage fattened bluefin tuna (Thunnus thynnus) were analyzed for proximate composition and fatty acid profile to evaluate the possibility of producing tuna oil (TO) as a valuable source of ω-3 polyunsaturated fatty acids (PUFA) and testing its bioactivity in vitro. Ethyl esters of total fatty acids (TFA), obtained from TO, were pre-enriched by urea complexation (PUFA-Ue) and then enriched by short path distillation (SPD) up to almost 85% of the PUFA fraction (PUFA-SPe). The bioactivity of TFA, PUFA-SPe, and ethyl esters of depleted PUFA (PUFA-SPd) were tested in vitro, through analysis of lipid metabolism genes, in gilthead sea bream (Sparus aurata) fibroblast cell line (SAF-1) exposed to oils. TFA and PUFA-SPd upregulated transcription factors (pparβ and pparγ) and lipid metabolism-related genes (D6D, fas, fabp, fatp1, and cd36), indicating the promotion of adipogenesis. PUFA-SPe treated cells were similar to control. PUFA-SPe extracted from farmed bluefin tuna side streams could be utilized in fish feed formulations to prevent excessive fat deposition, contributing to improving both the sustainability of aquaculture and the quality of its products. Full article

Aquaculture supplies more than 50% of the total fish consumed by the world population. It is considered by FAO authorities that it will be the main source of fishery products by 2030. These positive data are contradicted by the fact that aquaculture relies too much on fish oil and fish meal as essential ingredients for food, which exerts significant pressure on marine ecosystems. The present study was planned to look for alternative ingredients in aquafeeds and three different ingredients were evaluated for the first time in juveniles of rainbow trout: (1) House cricket, Acheta domesticus, meal (DI) as a quality protein source; (2) a mixture of four marine microalgae species (DM), as an important source of protein and lipids; (3) protein and lipid fraction recovered from cooking water from canned tuna manufacturing processes (DP&L); and (4) a mix of the three ingredients (DMIX). All the feeds assayed were compared with a commercial feed (DC). Results showed that the formulated alternative feeds had different effects on the growth of the fish. DI and DP&L have a similar growth performance to the control, while the fish fed with DM and the DMix have a slightly lower growth (p < 0.05). No significant differences were observed in terms of FCR (Feed Conversion Ratio) and PER (Protein Efficiency Ratio) (p < 0.05). Fish muscle composition did not show any differences in moisture, protein, lipids and carbohydrates content. Only a significant difference was detected in ash and in saturated fatty acid (SFA) content (p < 0.05). The hepatosomatic index (HSI) was significantly reduced in DI compared to that observed for the DC (p < 0.05), whereas the viscerosomatic index (VSI) was significantly higher in DM. The nutritional value of the rainbow trout muscle at the end of the study shows that DM fed fish showed the highest PUFA/SFA ratio and the lowest atherogenic index (AI), whereas DMIX showed the lowest PUFA/SFA and the highest n-3/n-6 and AI. No differences were observed among diets in the thrombogenic index (TI) values. Any of these ingredients might be used as alternative sources of protein in feeds for fish aquaculture because no negative effects were detected on fish growth, muscle composition, fish health or final nutritional value, except in the case of microalgae, which needs more research to adjust its inclusion rate in the feed. Full article