Omega-3-Rich Oils from Marine Side Streams and Their Potential Application in Food.

Rapid population growth and increasing food demand have impacts on the environment due to the generation of residues, which could be managed using sustainable solutions such as the circular economy strategy (waste generated during food processing must be kept within the food chain). Reusing discarded fish remains is part of this management strategy, since they contain high-value ingredients and bioactive compounds that can be used for the development of nutraceuticals and functional foods. Fish side streams such as the head, liver, or skin or the cephalothorax, carapace, and tail from shellfish are important sources of oils rich in omega-3. In order to resolve the disadvantages associated with conventional methods, novel extraction techniques are being optimized to improve the quality and the oxidative stability of these high-value oils. Positive effects on cardiovascular and vision health, diabetes, cancer, anti-inflammatory and neuroprotective properties, and immune system improvement are among their recognized properties. Their incorporation into different model systems could contribute to the development of functional foods, with market benefits for consumers. These products improve the nutritional needs of specific population groups in a scenario where noncommunicable diseases and pandemic crises are responsible for several deaths worldwide.

From Fish Waste to Value: An Overview of the Sustainable Recovery of Omega-3 for Food Supplements.

The disposal of food waste is a current and pressing issue, urging novel solutions to implement sustainable waste management practices. Fish leftovers and their processing byproducts represent a significant portion of the original fish, and their disposal has a high environmental and economic impact. The utilization of waste as raw materials for the production of different classes of biofuels and high-value chemicals, a concept known as "biorefinery", is gaining interest in a vision of circular economy and zero waste policies. In this context, an interesting route of valorization is the extraction of omega-3 fatty acids (ω-3 FAs) for nutraceutical application. These fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have received attention over the last decades due to their beneficial effects on human health. Their sustainable production is a key process for matching the increased market demand while reducing the pressure on marine ecosystems and lowering the impact of waste production. The high resale value of the products makes this waste a powerful tool that simultaneously protects the environment and benefits the global economy. This review aims to provide a complete overview of the sustainable exploitation of fish waste to recover ω-3 FAs for food supplement applications, covering composition, storage, and processing of the raw material.

A novel cold biorefinery approach for isolation of high quality fish oil in parallel with gel-forming proteins.

The pH-shift process for isolation of gel-forming proteins from fish processing by-products was extended to allow parallel isolation of fish oil. Subjecting the floating emulsion layer formed during pH-shift processing of salmon by-products to pH-adjustment or freeze/thawing efficiently released the emulsified oil at 4 °C. However, for herring by-products higher temperature (10 °C) and a combination of the emulsion-breaking techniques was required for efficient oil release. Oil recovery yield using the adjusted pH-shift process was lower than with classic heat-induced oil isolation (90 °C/20 min), but pH-shift-produced oils had higher amounts of n-3 polyunsaturated fatty acids (n-3 PUFA). Also, alkaline pH-shift processing produced oils with remarkably less oxidation products and free fatty acids compared with acid pH-shift process or heat-induced isolation. Extending the pH-shift process with emulsion breaking techniques can thus be a promising biorefinery approach for parallel cold production of high-quality fish oil and gel-forming proteins from fish by-products.

A comparative neurobehavioral study of sesame oil and fish oil on experimental animals.

Natural oils are enriched with polyunsaturated fatty acids (PUFAs) which are important for our health. Recent experimental data explained that PUFAs might have a beneficial effect on various brain functions such as anxiety, dementia, epileptic seizures, depression or bipolar and other neurobehavioral diseases. The objective of the current research work was to evaluate the effect of sesame oil, fish oil and mixture of both oils (1:1) on neurobehavioral changes and cognition. For this purpose shark fish oil and sesame oil were extracted out and there poly unsaturated and saturated fatty acids were analyzed by using GCFID that exposed the presence of different PUFs in shark fish oil, sesame oil and mixture of both oils. Neurobehavioral changes were seen after 5ml/kg/day sesame oil, 5ml/kg/day shark fish oil and 1:1 combination of both oil 5ml/kg/day administration on open field, cage crossing, light and dark, stationary rod, forced swimming induced depression test and water maze test. Our GCFID results showed sesame and fish oil enriched with higher amount of PUFs and showed significant anxiolytic and antidepressant like effect after 30 days of treatment (P<0.05) however combination of these both oils exhibited greater efficacy (P<0.01) in reducing anxiety and depression as imipramine standard drug. Results showed that combination of both oils (sesame oil and fish oil) could be a better option to treat neurobehavioral problems as compared to alone.

Valorization of Aquaculture By-Products of Salmonids to Produce Enzymatic Hydrolysates: Process Optimization, Chemical Characterization and Evaluation of Bioactives.

In the present manuscript, various by-products (heads, trimmings, and frames) generated from salmonids (rainbow trout and salmon) processing were evaluated as substrates for the production of fish protein hydrolysates (FPHs), potentially adequate as protein ingredients of aquaculture feeds. Initially, enzymatic conditions of hydrolysis were optimized using second order rotatable designs and multivariable statistical analysis. The optimal conditions for the Alcalase hydrolysis of heads were 0.1% (v/w) of enzyme concentration, pH 8.27, 56.2°C, ratio (Solid:Liquid = 1:1), 3 h of hydrolysis, and agitation of 200 rpm for rainbow trout and 0.2% (v/w) of enzyme, pH 8.98, 64.2 °C, 200 rpm, 3 h of hydrolysis, and S:L = 1:1 for salmon. These conditions obtained at 100 mL-reactor scale were then validated at 5L-reactor scale. The hydrolytic capacity of Alcalase and the protein quality of FPHs were excellent in terms of digestion of wastes (Vdig > 84%), high degrees of hydrolysis (Hm > 30%), high concentration of soluble protein (Prs > 48 g/L), good balance of amino acids, and almost full in vitro digestibility (Dig > 93%). Fish oils were recovered from wastes jointly with FPHs and bioactive properties of hydrolysates (antioxidant and antihypertensive) were also determined. The salmon FPHs from trimmings + frames (TF) showed the higher protein content in comparison to the rest of FPHs from salmonids. Average molecular weights of salmonid-FPHs ranged from 1.4 to 2.0 kDa and the peptide sizes distribution indicated that hydrolysates of rainbow trout heads and salmon TF led to the highest percentages of small peptides (0-500 Da).

Tolerability and Safety of a Nutritional Supplement with Potential as Adjuvant in Colorectal Cancer Therapy: A Randomized Trial in Healthy Volunteers.

Bioactive supplements display relevant therapeutic properties when properly applied according to validated molecular effects. Our previous research efforts established the basis to develop a dietary supplement based on a Rosmarinus officinalis supercritical extract. This was enriched in phenolic diterpenes (RE) with proven properties against signaling pathways involved in colon tumorigenesis, and shark liver oil rich in alkylglycerols (AKG) as a bioactive lipid vehicle to improve RE bioavailability and synergize with the potential therapeutic action of the extract. Herein, we have investigated the tolerability and safety of the supplement and the biological and molecular effects from an immuno-nutritional perspective. Sixty healthy volunteers participated in a six week, double-blind, randomized parallel pilot study with two study arms: RE-AKG capsules (CR) and control capsules (CC). Mean age (±SD) of volunteers was 28.32 (±11.39) and 27.5 (±9.04) for the control and the study groups, respectively. Safety of the CR product consumption was confirmed by analyzing liver profile, vital constants, and oxidation markers (LDLox in blood and isoprostanes and thromboxanes in urine). The following were monitored: (1) the phenotyping of plasmatic leukocytes and the ex vivo response of lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs); (2) expression of genes associated with immune-modulation, inflammation, oxidative stress, lipid metabolism, and tumorigenesis; and (3) the correlation of selected genetic variants (SNPs) with the differential responses among individuals. The lack of adverse effects on liver profile and oxidation markers, together with adequate tolerability and safe immunological adaptations, provide high-quality information for the potential use of CR as co-adjuvant of therapeutic strategies against colorectal cancer.

Highly concentrated omega-3 fatty acid ethyl esters by urea complexation and molecular distillation.

BACKGROUND: Raya liver deodorized oil contains high concentrations of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). The present study investigated the processes of urea complexation (UC) and molecular distillation (MD) to determine the most adequate operation conditions for each process, separately and together, aiming to obtain highly concentrated EPA, DPA and DHA ethyl esters with chemical indicator values permitted by the current legislation for edible oils. RESULTS: In the second stage of MD, a concentration of 820.27 g kg-1 in the distillate and 951.06 g kg-1 of omega-3 fatty acid ethyl esters in the residue was obtained. The distillate showed values of free fatty acids, peroxide and p-anisidine lower than the maximum allowed for edible oils in accordance with the current legislation. CONCLUSION: The use of UC and MD together has revealed a significant improvement in the total concentration of omega-3 fatty acid ethyl esters in the final product and good application prospects. © 2018 Society of Chemical Industry.

Effects of antioxidative substances from seaweed on quality of refined liver oil of leafscale gulper shark, Centrophorus squamosus during an accelerated stability study.

Crude liver oil of leafscale gulper shark, Centrophorus squamosus was clarified by sequential degumming, decolorization and vacuum deodorization. The refined oil was added with ethyl acetate extract of seaweeds and various physiochemical parameters were evaluated in a time-reliant accelerated storage study. Significantly greater induction time was observed for the oil supplemented with Sargassum wightii and Sargassum ilicifolium (>4.5h) than other seaweed extracts and control oil (~1h). Among different seaweeds, the ethylacetate extracts of S. wightii maintained the oxidation indices of the refined oil below the marginal limits after the study period. No significant reduction in C20-22 long chain fatty acids (1.19%) in the refined oil added with S. wightii was apparent, and was comparable with the synthetic antioxidants (1.07-1.08%). Spectroscopic fingerprint analysis of marker compounds responsible to cause rancidity signified the efficacy of S. wightii to arrest the development of undesirable oxidation products in the refined oil during storage. The antioxidant compounds, 15-(but-19-enyl)-hexahydro-13,16-dimethyl-11-oxo-1H-isochromen-8-yl benzoate (1) and 10-(but-13-en-12-yl)-5-((furan-3-yl)propyl)-dihydrofuran-9(3H)-one (2) isolated from S. wightii appeared to play a major role to deter the oxidative degradation of refined oil thereby enhancing the storage stability.

Synthesis of High-Quality Biodiesel Using Feedstock and Catalyst Derived from Fish Wastes.

A low-cost and high-purity calcium oxide (CaO) was prepared from waste crab shells, which were extracted from the dead crabs, was used as an efficient solid base catalyst in the synthesis of biodiesel. Raw fish oil was extracted from waste parts of fish through mechanical expeller followed by solvent extraction. Physical as well as chemical properties of raw fish oil were studied, and its free fatty acid composition was analyzed with GC-MS. Stable and high-purity CaO was obtained when the material was calcined at 800 °C for 4 h. Prepared catalyst was characterized by XRD, FT-IR, and TGA/DTA. The surface structure of the catalyst was analyzed with SEM, and elemental composition was determined by EDX spectra. Esterification followed by transesterification reactions were conducted for the synthesis of biodiesel. The effect of cosolvent on biodiesel yield was studied in each experiment using different solvents such as toluene, diethyl ether, hexane, tetrahydrofuran, and acetone. High-quality and pure biodiesel was synthesized and characterized by 1H NMR and FT-IR. Biodiesel yield was affected by parameters such as reaction temperature, reaction time, molar ratio (methanol:oil), and catalyst loading. Properties of synthesized biodiesel such as density, kinematic viscosity, and cloud point were determined according to ASTM standards. Reusability of prepared CaO catalyst was checked, and the catalyst was found to be stable up to five runs without significant loss of catalytic activity.

Mugil cephalus roe oil obtained by supercritical fluid extraction affects the lipid profile and viability in cancer HeLa and B16F10 cells.

We explored the changes in viability and lipid profile occurring in cancer cells, murine melanoma cells (B16F10 cells) and human cervical carcinoma cells (HeLa cells), when exposed to 24 h-treatments with an n-3 PUFA-rich oil obtained by supercritical extraction with CO2 from Mugil cephalus processed roe (bottarga). The composition of the major lipid classes of bottarga oil was determined by the (13)C NMR technique. Reversed-phase HPLC with DAD/ELSD detection was performed to analyze cells' total fatty acid profile and the levels of phospholipids, total/free cholesterol, triacylglycerols, and cholesteryl esters. Cell-based fluorescent measurements of intracellular membranes and lipid droplets were performed on bottarga oil-treated cells using the Nile red staining technique. The treatments of cancer cells with bottarga oil reduced the viability and affected the fatty acid profile, with a significant n-3 PUFA increase in treated cells. Mullet roe oil uptake modulated the cancer cell lipid composition, inducing a remarkable incorporation of health beneficial n-3 PUFA in the polar and neutral lipid fractions. Bottarga oil treatment influenced the synthesis of intracellular membranes and accumulation of cytoplasmic lipid droplets in cancer cells.

Alkylglycerols reduce serum complement and plasma vascular endothelial growth factor in obese individuals.

Alkylglycerols (AKGs), isolated or present in shark liver oil have anti-inflammatory properties. Complement 3 (C3) and 4 (C4) participate in lipid metabolism and in obesity, contributing to the metabolic syndrome and to the low-grade inflammation associated with obesity. In a randomized, controlled, crossover study, 26 non-diabetes obese individuals were assigned two preparations with low (LAC, 10 mg AKGs) and high (HAC, 20 mg AKGs) AKG content. Intervention periods were of 3 weeks preceded by 2-week washout periods in which shark liver oil was avoided. Cholesterol, C3, C4, and vascular endothelial growth factor (VEGF) decreased in a linear trend (P < 0.01) from baseline (control) to LAC and HAC. Values after HAC were significantly lower (P < 0.05) versus both baseline and after LAC. No adverse effects were observed or reported. Data from this pilot study open a promising field for the study of the beneficial effects of AKGs on cardiovascular risk factors in obese individuals.

Prediction of oxidation parameters of purified Kilka fish oil including gallic acid and methyl gallate by adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network.

BACKGROUND: As a result of concerns regarding possible health hazards of synthetic antioxidants, gallic acid and methyl gallate may be introduced as natural antioxidants to improve oxidative stability of marine oil. Since conventional modelling could not predict the oxidative parameters precisely, artificial neural network (ANN) and neuro-fuzzy inference system (ANFIS) modelling with three inputs, including type of antioxidant (gallic acid and methyl gallate), temperature (35, 45 and 55 °C) and concentration (0, 200, 400, 800 and 1600 mg L(-1) ) and four outputs containing induction period (IP), slope of initial stage of oxidation curve (k1 ) and slope of propagation stage of oxidation curve (k2 ) and peroxide value at the IP (PVIP ) were performed to predict the oxidation parameters of Kilka oil triacylglycerols and were compared to multiple linear regression (MLR). RESULTS: The results showed ANFIS was the best model with high coefficient of determination (R(2) = 0.99, 0.99, 0.92 and 0.77 for IP, k1 , k2 and PVIP , respectively). So, the RMSE and MAE values for IP were 7.49 and 4.92 in ANFIS model. However, they were to be 15.95 and 10.88 and 34.14 and 3.60 for the best MLP structure and MLR, respectively. So, MLR showed the minimum accuracy among the constructed models. CONCLUSION: Sensitivity analysis based on the ANFIS model suggested a high sensitivity of oxidation parameters, particularly the induction period on concentrations of gallic acid and methyl gallate due to their high antioxidant activity to retard oil oxidation and enhanced Kilka oil shelf life. © 2016 Society of Chemical Industry.

Novel promising therapeutics against chronic neuroinflammation and neurodegeneration in Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by deposition of amyloid plaques and neurofibrillary tangles, as well as microglial and astroglial activation, and, finally, leading to neuronal dysfunction and death. Current treatments for AD primarily focus on enhancement of cholinergic transmission. However, these treatments are only symptomatic, and no disease-modifying drug is available for the treatment of AD patients. This review will provide an overview of the antioxidant, anti-inflammatory, anti-amyloidogenic, neuroprotective, and cognition-enhancing effects of a variety of nutraceuticals including curcumin, apigenin, docosahexaenoic acid, epigallocatechin gallate, α-lipoic acid and resveratrol and their potential for AD prevention and treatment. We suggest that therapeutic use of these compounds might lead to a safe strategy to delay the onset of AD or slow down its progression. The continuing investigation of the potential of these substances is necessary as they are promising compounds to yield a possible remedy for this pervasive disease.

Seasonal variations in the regiodistribution of oil extracted from small-spotted catshark and bogue.

The aim of this work was to seasonally characterize the nutritional quality of oil extracted from small-spotted catshark (Scyliorhinus canicula) and bogue (Boops boops). The proximate composition, lipid profile and regiodistribution of the fatty acid in the glycerol backbone were analyzed. In addition, three nutritional indexes were calculated (atherogenicity and thrombogenicity indexes and the hypocholesterolaemic/hypercholesterolaemic ratio). Both species presented PUFA as the predominant fraction, the most abundant being DHA. Healthy values of the aforementioned indexes were maintained throughout the year. Moreover, the relative composition of omega 3 fatty acids at the sn-2 position ranged from 47.3 to 66.8 mol%, attracting interest in the employment of these oils as the raw source for the production of 2-monoacylglycerols. Regarding the individual behavior of each fatty acid, DHA presented a high tendency to occupy the sn-2 bond, whereas EPA presented the opposite behavior.

Purification of Alaskan walleye pollock (Gadus chalcogrammus) and New Zealand hoki (Macruronus novaezelandiae) liver oil using short path distillation.

The beneficial health effects of a diet rich in n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA) have been extensively researched in recent years. Marine oils are an important dietary source of n-3 LC-PUFA, being especially rich in two of the most important fatty acids of this class, EPA (eicosapentaenoic acid; 20:5n-3) and DHA (docosahexaenoic acid; 22:6n-3). Oils rich in n-3 LC-PUFA are prone to oxidation that leads to loss of product quality. Alaskan pollock (Gadus chalcogrammus Pallas, 1814) and New Zealand's hoki (Macruronus novaezelandiae Hector, 1871) are the highest volume fisheries of their respective countries. Both produce large quantities of fishery byproducts, in particular crude or unrefined n-3 LC-PUFA containing oils. Presently these oils are used as ingredients for animal feed, and only limited quantities are used as human nutritional products. The aim of this research was to investigate the applicability of short path distillation for the purification of pollock and hoki oil to produce purified human-grade fish oil to meet quality specifications. Pollock and hoki oils were subjected to short path distillation and a significant decrease in free fatty acids and lipid oxidation (peroxide and para-anisidine values) products was observed. Purified oils met the Global Organization for EPA and DHA Omega-3 (GOED) standard for edible fish oils.

Antitumor and anti-cachectic effects of shark liver oil and fish oil: comparison between independent or associative chronic supplementation in Walker 256 tumor-bearing rats.

BACKGROUND: Shark liver oil (SLOil) and fish oil (FOil), which are respectively rich in alkylglycerols (AKGs) and n-3 polyunsaturated fatty acids (PUFAs), are able to reduce the growth of some tumors and the burden of cachexia. It is known that FOil is able to reduce proliferation rate and increase apoptotic cells and lipid peroxidation of tumor cells efficiently. However, there are few reports revealing the influence of SLOil on these parameters. In the current study, effects of FOil chronic supplementation on tumor growth and cachexia were taken as reference to compare the results obtained with SLOil supplementation. Also, we evaluated if the association of SLOil and FOil was able to promote additive effects. METHODS: Weanling male Wistar rats were divided into 4 groups: fed regular chow (C), supplemented (1 g/kg body weight) with SLOil (CSLO), FOil (CFO) and both (CSLO + FO). After 8 weeks half of each group was inoculated with Walker 256 cells originating new groups (W, WSLO, WFO and WSLO + FO). Biochemical parameters of cachexia, tumor weight, hydroperoxide content, proliferation rate and percentage of apoptotic tumor cells were analysed. Fatty acids and AKG composition of tumor and oils were obtained by high performance liquid chromatography and gas chromatography - mass spectrometry, respectively. Statistical analysis was performed by unpaired t-test and one-way ANOVA followed by a post hoc Tukey test. RESULTS: Fourteen days after inoculation, SLOil was able to restore cachexia parameters to control levels, similarly to FOil. WSLO rats presented significantly lower tumor weight (40%), greater tumor cell apoptosis (~3-fold), decreased tumor cell proliferation (35%), and higher tumor content of lipid hydroperoxides (40%) than observed in W rats, but FOil showed more potent effects. Supplementation with SLOil + FOil did not promote additive effects. Additionally, chromatographic results suggested a potential incorporation competition between the n-3 fatty acids and the AKGs in the tumor cells' membranes. CONCLUSIONS: SLOil is another marine source of lipids with similar FOil anti-cachectic capacity. Furthermore, despite being less potent than FOil, SLOil presented significant in vivo antitumor effects. These results suggest that the chronic supplementation with SLOil may be adjuvant of the anti-cancer therapy.

Rapid isolation of omega-3 long-chain polyunsaturated fatty acids using monolithic high performance liquid chromatography columns.

Eicosapentaenoic and docosahexaenoic acids are important bio-active fatty acids in fish oils. Monolithic HPLC columns both in the polymeric cation exchange (silver-ion) and RP formats were compared with corresponding packed columns for the isolation of these acids from tuna oil ethyl esters. Monolithic columns in both formats enabled rapid (typically 5-10 min) separations compared with packed columns (30 min). Polymeric monolithic silver-ion disc column rapidly furnished mixtures of eicosapentaenoic and docosahexaenoic esters (90% purity) within 5-10 min, but was unable to resolve individual esters. A preparative version of the same column (80 mL bed volume) enabled isolation (>88% purity) of 100 mg quantities of eicosapentaenoic and docosahexaenoic esters from esterified tuna oil within 6 min. Baseline separation of eicosapentaenoic and docosahexaenoic esters was achieved on all RP columns. The results show that there is potential to use polymeric monolithic cation exchange columns for scaled-up preparation of eicosapentaenoic and docosahexaenoic ester concentrates from fish oils.

Extraction, processing, and stabilization of health-promoting fish oils.

Fish oil is known to be an important source of highly unsaturated n-3 polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which play an important role in the prevention of different human diseases. Fortification of foods with such fatty acids is, thus, increasingly recommended. A growing public awareness about the benefits and the limited dietary sources of PUFA has created a substantial interest in the production of PUFA concentrate. Thus, ecofriendly extraction and purification techniques, exhibiting higher yield and minimum degradation of the nutrient, are of prime focus among the researchers. Due to the presence of these highly unsaturated PUFA, fish oil is highly prone to oxidation, leading to the production of off-odors and off-flavors. Presently, synthetic antioxidants have been replaced by natural ones for stabilizing the fish oil against oxidation. This article reviews major research and patents that have been published on fish oil extraction, purification and its stability.

Elimination of persistent organic pollutants from fish oil with solid adsorbents.

Fish oils are one of the main sources of ω-3 fatty acids in animal and human diet. However, they can contain high concentrations of persistent organic pollutants due to their lipophilic properties. The aim of this study is the reduction of persistent organic pollutants in fish oil using silicon-based and carbon-based solid adsorbents. A wide screening study with different commercially available adsorbents was carried out, in order to determine their capacity of pollutant removal from fish oil. Moreover, adsorption conditions were evaluated and optimized with using an experimental design and adjustment of the experimental results to response surfaces, obtaining removals rates of more than 99% of PCDD/Fs, 81% of dioxin-like PCBs, 70% of HCB, 41% of DDTs, 16% of marker PCBs and 10% of PBDEs. Finally, fish oil fatty acids were analyzed before and after the treatment with solid adsorbents, confirming that it did not affect its nutritive properties.