Extraction of fish oil using green extraction methods: a short review

A novel micro-aqueous cold extraction of salmon head oil to reduce lipid oxidation and fishy odor: Comparison with common methods

Traditional heat extraction (HE) has a low efficiency (75.2 wt%) and induces lipid oxidation of PUFAs. The novel micro-aqueous cold (<25 °C) extraction (MAE) was applied to extract salmon head oil. The recovery rate was 93.4 wt% at oil volume fraction Φ = 74 %. The extraction mechanism was agitation-induced droplet coalescence at an unstable and close-packing state (Φ = 74 %), increasing the portions of the large-sized droplets (>50 μm) from 2.8 vol% to 91.7 vol%. The MAE reduced the oil oxidation level and odor intensity compared to HE, although the lipid profile differed slightly. The HE head oil had more key fishy odor compounds, including hexanal (0.98 mg/kg), 3-methyl-butanal (0.25 mg/kg), 1-penten-3-ol (0.49 mg/kg), and 2-ethylfuran (0.19 mg/kg). The MAE oil had only 2-methyl-butanal (0.10 mg/kg) and 1-penten-3-ol (0.47 mg/kg). Overall, micro-aqueous extraction has great potential to replace industrial heat extraction with a better product quality.

The Revalorization of Fishery By-Products: Types, Bioactive Compounds, and Food Applications

Recently, fish consumption has been increasing; subsequently, the number of by-products has also increased. However, generated residues are frequently discarded, and an appropriate management is necessary to properly use all fish by-products. Fishery by-products are well known for their content of bioactive compounds, such as unsaturated fatty acids, amino acids, minerals, peptides, enzymes, gelatin, collagen, and chitin. Several studies have reported that fishery by-products could provide significant properties, including antioxidant, antihypertensive, antimicrobial, anti-inflammatory, and antiobesity. Consequently, fish discards are of considerable interest to different industrial sectors, including food, nutraceuticals, medical, and pharmacology. In the food industry, the interest in using fishery by-products is focused on hydrolysates as food additives, collagen and gelatin as protein sources, chitin and chitosan to form edible films to protect food during storage, and oils as a source of Omega-3 and useful as antioxidants. Although different studies reported good results with the use of these by-products, identifying new applications in the food sector, as well as industrial applications, remains necessary.

Investigating the impact of wet rendering (solventless method) on PUFA-rich oil from catfish (Clarias magur) viscera

Catfish (Clarias magur) is a popular freshwater fish food worldwide. The processing of this fish generates a significant amount of waste, mainly in the form of viscera, which constitutes around 10-12% of the fish's total weight. This study was focused on extracting polyunsaturated fatty acid (PUFA)-rich oil from catfish viscera, aiming to enhance the extraction process and make the production of oil and handling of fish byproducts more cost-effective. The wet reduction method, a solvent-free approach, was used for extraction, with yield optimization done via the Box-Behnken design. The resulting oil was evaluated for its oxidative quality and chemical characteristics. The optimal conditions for the wet rendering process were as follows: viscera to water ratio, 1:0.5 (w/v); temperature, 90℃; and time, 20 min, yielding 12.40 g/100 g of oil. The oil extracted under optimal wet rendering conditions had quality and oxidative stability comparable to solvent extraction and fewer secondary oxidation compounds. This oil had a higher PUFA content, specifically a 4:1 ratio of omega 6 to omega 3. Such oil, derived from catfish viscera, is suitable for the food industry due to its solvent-free extraction method.

Marine Animal Co-Products-How Improving Their Use as Rich Sources of Health-Promoting Lipids Can Foster Sustainability

Marine lipids are recognized for their-health promoting features, mainly for being the primary sources of omega-3 fatty acids, and are therefore critical for human nutrition in an age when the global supply for these nutrients is experiencing an unprecedent pressure due to an ever-increasing demand. The seafood industry originates a considerable yield of co-products worldwide that, while already explored for other purposes, remain mostly undervalued as sustainable sources of healthy lipids, often being explored for low-value oil production. These co-products are especially appealing as lipid sources since, besides the well-known nutritional upside of marine animal fat, which is particularly rich in omega-3 polyunsaturated fatty acids, they also have interesting bioactive properties, which may garner them further interest, not only as food, but also for other high-end applications. Besides the added value that these co-products may represent as valuable lipid sources, there is also the obvious ecological upside of reducing seafood industry waste. In this sense, repurposing these bioresources will contribute to a more sustainable use of marine animal food, reducing the strain on already heavily depleted seafood stocks. Therefore, untapping the potential of marine animal co-products as valuable lipid sources aligns with both health and environmental goals by guaranteeing additional sources of healthy lipids and promoting more eco-conscious practices.

Oil from Mullet Roe Byproducts: Effect of Oil Extraction Method on Human Erythrocytes and Platelets

Background: The valorization of byproducts to obtain high nutritional value foods is of utmost importance for our planet where the population is booming. Among these products are oils rich in ω-3 fatty acids produced from fishery byproducts. Recently, mullet roe oil from roe byproducts was produced that was rich in the ω-3 fatty acids eicosatetraenoic acid (EPA) and docosahexaenoic acid (DHA). Oils are customarily characterized for their composition and degree of oxidation but little is known of their biological effects, especially the effect of the extraction method. Methods: The purpose of this study was to evaluate the effects of freshly extracted mullet roe oil from mullet roe byproducts and the effect of the extraction method on human red blood cells (hRBCs) and platelets. To this end, the hemocompatibility (cytotoxicity), oxidative effects, and erythrocyte membrane changes were examined after 1 and 24 h of incubation. Antiplatelet effects were also assessed in vitro. Results: The expeller press oil extraction method and alcalase-assisted extraction produced the most biocompatible oils, as shown by hemocompatibility measurements and the absence of erythrocyte membrane alterations. Solvent extracts and protease-assisted extraction oils resulted in the rupture of red blood cells at different examined dilutions, creating hemolysis. Conclusions: It seems that the proper functioning of oil-erythrocyte interactions cannot be explained solely by ROS. Further investigations combining chemical analysis with oil-cell interactions could be used as an input to design high nutritional value oils using green extraction technologies. All samples exhibited promising antiplatelet and antiblood clotting effects in vitro.

Influence of solvent-free extraction of fish oil from catfish (Clarias magur) heads using a Taguchi orthogonal array design: A qualitative and quantitative approach

This study aimed to efficiently utilize catfish heads, enhancing the oil extraction process while improving the cost-effectiveness of fish byproduct management. The study employed the wet rendering method, a solvent-free approach, utilizing a two-factor Taguchi orthogonal array design to identify critical parameters for optimizing oil yield and ensuring high-quality oil attributes. The extraction temperature (80-120°C) and time (5-25 min) were chosen as variables in the wet rendering process. Range analysis identified the extraction time as a more significant (p < 0.05) factor for most parameters, including oil yield, oil recovery, acid value, free fatty acids, peroxide value, and thiobarbituric acid reactive substances. The extraction temperature was more significant (p < 0.05) for oil color. Consequently, the wet rendering method was optimized, resulting in an extraction temperature of 80°C and an extraction time of 25 min, yielding the highest oil yield. This optimized wet rendering process recovered 6.37 g/100 g of oil with an impressive 54.16% oil recovery rate, demonstrating comparable performance to traditional solvent extraction methods. Moreover, Fourier transfer infrared spectra analysis revealed distinct peaks associated with triacylglycerols and polyunsaturated fatty acids (PUFA). The oil recovered under optimized conditions contained higher levels of PUFA, including oleic acid (189.92 μg/g of oil), linoleic acid (169.92 μg/g of oil), eicosapentaenoic acid (17.41 μg/g of oil), and docosahexaenoic acid (20.82 μg/g of oil). Volatile compound analysis revealed lower levels of secondary oxidation compounds under optimized conditions. This optimized wet rendering method offers practical advantages in terms of cost-efficiency, sustainability, reduced environmental impact, and enhanced oil quality, making it an attractive option for the fish processing industries. Future research possibilities may include the purification of the catfish head oil and its application in the food and pharmaceutical industries.

Trends in fisheries waste utilization: a valuable resource of nutrients and valorized products for the food industry

The rise in fisheries production worldwide has caused a remarkable increase in associated anthropogenic waste. This poses significant concerns due to adverse environmental impacts and economic losses. Owing to its renewability, high abundance, and potential as a rich source of many nutrients and bioactive compounds, strategies have been developed to convert fish waste into different value-added products. Conventional and improved methods have been used for the extraction of biomolecules from fish waste. The extracted fish waste-derived value-added products such as enzymes, peptides, fish oil, etc. have been used to fortify different food products. This review aims to provide an overview of the nature and composition of fish waste, strategies for extracting biomolecules from fish waste, and the potential application of fish waste as a source of calcium and other nutrients in food fortification and animal feed has been discussed. In context to fishery waste mitigation, valorization, and circular bioeconomy approach are gaining momentum, aiming to eliminate waste while producing high-quality value-added food and feed products from fishery discards.

Impact of cavitation on the structure and functional quality of extracted protein from food sources - An overview

Increasing protein demands directly require additional resources to those presently and recurrently available. Emerging green technologies have witnessed an escalating interest in "Cavitation Processing" (CP) to ensure a non-invasive, non-ionizing and non-polluting extraction. The main intent of this review is to present an integrated summary of cavitation extraction methods specifically applied to food protein sources. Along with a comparative assessment carried out for each type of cavitation model, protein extraction yield and implications on the extracted protein's structural and functional properties. The basic principle of cavitation is due to the pressure shift in the liquid flow within milliseconds. Hence, cavitation emerges similar to boiling; however, unlike boiling (temperature change), cavitation occurs due to pressure change. Characterization and classification of sample type is also a prime candidate when considering the applications of cavitation models in food processing. Generally, acoustic and hydrodynamic cavitation is applied in food applications including extraction, brewing, microbial cell disruption, dairy processing, emulsification, fermentation, waste processing, crystallisation, mass transfer and production of bioactive peptides. Micro structural studies indicate that shear stress causes disintegration of hydrogen bonds and Van der Waals interactions result in the unfolding of the protein's secondary and/or tertiary structures. A change in the structure is not targeted but rather holistic and affects the physicochemical, functional, and nutritional properties. Cavitation assisted extraction of protein is typically studied at a laboratory scale. This highlights limitations against the application at an industrial scale to obtain potential commercial gains.

HPLC/HRMS and GC/MS for Triacylglycerols Characterization of Tuna Fish Oils Obtained from Green Extraction

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.

Fatty Acid Positions in Triacylglycerol of Iridescent Shark Fish Oil (Pangasius sp.), Focusing on Omega-3 and Omega-6 Fatty Acids

<b>Background and Objective:</b> Considering the many health benefits of fish oil, the potential of Indonesian fisheries needs to be mapped to find local fish oil sources that have the opportunity to be used as a source of omega-3 and 6. This research aimed to ascertain the glyceride profile of iridescent shark fish oil hydrolyzed by immobilized lipase from <i>Thermomyces lanuginosus</i> at the sn-1,3 position and identify the position of omega-3 and omega-6 fatty acids. <b>Materials and Methods:</b> To extract the fish oil from the iridescent shark, the soxhletation method was utilized. The analysis of the fatty acid composition that was carried out using gas chromatography (GC) was previously esterified with BF₃ before it was carried out to position the fatty acid hydrolysis that was carried out using lipase enzymes to position the fatty acid composition. <b>Results:</b> The sample had more unsaturated fatty acids than saturated ones. Omega-3 and omega-6 fatty acids are more concentrated in the fat molecule's sn-2 position than in the sn-1+sn-3 location. Iridescent shark fish oil meets the recommended ratio of omega-3 to omega-6 (1:1) or better (2:1). <b>Conclusion:</b> It has been discovered that iridescent shark fish oil is rich in omega-3 and omega-6 fatty acids, especially those in the sn-2 position. This makes it a great food choice for those trying to get more omega-3 unsaturated fatty acids into their diets.

Highly Valuable Fish Oil: Formation Process, Enrichment, Subsequent Utilization, and Storage of Eicosapentaenoic Acid Ethyl Esters

In recent years, as the demand for precision nutrition is continuously increasing, scientific studies have shown that high-purity eicosapentaenoic acid ethyl ester (EPA-EE) functions more efficiently than mixed omega-3 polyunsaturated fatty acid preparations in diseases such as hyperlipidemia, heart disease, major depression, and heart disease; therefore, the market demand for EPA-EE is growing by the day. In this paper, we attempt to review EPA-EE from a whole-manufacturing-chain perspective. First, the extraction, refining, and ethanolysis processes (fish oil and ethanol undergo transesterification) of EPA-EE are described, emphasizing the potential of green substitute technologies. Then, the method of EPA enrichment is thoroughly detailed, the pros and cons of different methods are compared, and current developments in monomer production techniques are addressed. Finally, a summary of current advanced strategies for dealing with the low oxidative stability and low bioavailability of EPA-EE is presented. In conclusion, understanding the entire production process of EPA-EE will enable us to govern each step from a macro perspective and accomplish the best use of EPA-EE in a more cost-effective and environmentally friendly way.

Upcycling Fish By-Products into Bioactive Fish Oil: The Suitability of Microwave-Assisted Extraction

The seafood industry is often left out of the food waste discussion, but this sector is no exception, as it generates large amounts of various by-products. This study aimed to explore the potential of the microwave-assisted extraction (MAE) technique to obtain high-quality oil from fish by-products. The independent variables, which were time (1-30 min), microwave power (50-1000 W), and solid/liquid ratio (70-120 g/L) were combined in a 20-run experimental design coupled with the response surface methodology (RSM) for process optimization. The obtained oil yield values were fitted to a quadratic equation to build the theoretical models, which were statistically validated based on statistical criteria and used to predict the optimal MAE condition. The oil yields were significantly affected by the three independent variables through linear, quadratic, and/or interactive effects. Compared to a conventional Soxhlet extraction (SE), the optimal MAE conditions allowed between 60 and 100% of oil to be recovered in less than 19 min and with less solvent consumption. The fatty acid profiles of the oils obtained through SE and optimized MAE were characterized by gas chromatography with flame ionizing detection (GC-FID) after a derivatization process. These oils were constituted mainly of health, beneficial unsaturated fatty acids, such as oleic, docosahexaenoic (DHA), linoleic, and eicosapentaenoic (EPA) acids, which were not affected (p > 0.05) by the extraction methods. Interestingly, the oils obtained through MAE showed the best microbial growth inhibition results may have been due to thermolabile compounds, preserved via this unconventional non-thermal method. The oils also exhibited anti-inflammatory effects via nitric oxide production inhibition and cytotoxic potential especially, against breast and gastric adenocarcinoma cells. However, the threshold of toxicity should be further investigated. Overall, this work emerges as a future-oriented approach to upcycling fish by-products into high-quality oils that can be used in the formulation of pet food and other products.

Research Progress on Nutritional Value, Preservation and Processing of Fish-A Review

The global population has rapidly expanded in the last few decades and is continuing to increase at a rapid pace. To meet this growing food demand fish is considered a balanced food source due to their high nutritious value and low cost. Fish are rich in well-balanced nutrients, a good source of polyunsaturated fatty acids and impose various health benefits. Furthermore, the most commonly used preservation technologies including cooling, freezing, super-chilling and chemical preservatives are discussed, which could prolong the shelf life. Non-thermal technologies such as pulsed electric field (PEF), fluorescence spectroscopy, hyperspectral imaging technique (HSI) and high-pressure processing (HPP) are used over thermal techniques in marine food industries for processing of most economical fish products in such a way as to meet consumer demands with minimal quality damage. Many by-products are produced as a result of processing techniques, which have caused serious environmental pollution. Therefore, highly advanced technologies to utilize these by-products for high-value-added product preparation for various applications are required. This review provides updated information on the nutritional value of fish, focusing on their preservation technologies to inhibit spoilage, improve shelf life, retard microbial and oxidative degradation while extending the new applications of non-thermal technologies, as well as reconsidering the values of by-products to obtain bioactive compounds that can be used as functional ingredients in pharmaceutical, cosmetics and food processing industries.

Variability in Biological Activities of Satureja montana Subsp. montana and Subsp. variegata Based on Different Extraction Methods

Winter savory (Satureja montana L.) is a well-known spice and medicinal plant with a wide range of activities and applications. Two subspecies of S. montana, subsp. montana and subsp. variegata, were used for the preparation of seven different extracts: steam distillation (essential oil (EO) and hydrolate (HY)), subcritical water (SWE), ultrasound-assisted (UAE-MeOH and UAE-H2O), and microwave-assisted (MAE-MeOH and MAE-H2O) extraction. The obtained EOs, HYs, and extracts were used for an in vitro evaluation of the antioxidant activity (DPPH, ABTS, reducing power, and superoxide anion methods) and in vitro antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Salmonella Typhimurium, Saccharomyces cerevisiae, and Candida albicans. The antimicrobial screening was conducted using disk-diffusion assessment, minimal inhibitory concentration, time-kill kinetics modeling, and pharmacodynamic study of the biocide effect. The total phenolic content (TPC) was highest in EO, followed by SWE, MAE, and UAE, and the lowest was in HY. The highest antimicrobial activity shows EO and SWE for both varieties, while different UAE and MAE extracts have not exhibited antimicrobial activity. The natural antimicrobials in the S. montana extract samples obtained by green extraction methods, indicated the possibility of ecologically and economically better solutions for future in vivo application of the selected plant subspecies.

Resource recovery from fish waste: Prospects and the usage of intensified extraction technologies

Globally, the valorization of fish biowaste as a feedstock to recover valuable components is an emerging research and commercial interest area to achieve the SDG goals by 2030. Fish waste-derived biomolecules are increasingly finding diverse applications in food and other biotechnological fields due to their excellent chemical, structural and functional properties. The focus of this review is to highlight the conventional valorization routes and recent advancements in extraction technologies for resource recovery applications, primarily focusing on green processes. Biointensified processes involving ultrasound, microwave, sub- and supercritical fluids, pulsed electric field, high-pressure processing, and cold plasma are extensively explored as sustainable technologies for valorizing fish discards and found numerous applications in the production of functional and commercially important biomaterials. With challenges in recovering intracellular bioactive compounds, selectivity, and energy requirement concerns, conventional approaches are being relooked continuously in the quest for process intensification and sustainable production practices. Nonetheless, in the context of 'zero waste' and 'biorefinery for high-value compounds', there is immense scope for technological upgradation in these emerging alternative approaches. This work details such attempts, providing insights into the immense untapped potential in this sector.

Biochemical characterization of Soxhlet-extracted pulp oil of Canarium schweinfurthii Engl. fruit in Nigeria

Characterization and further development of underutilized/underexploited indigenous tropical seed oils are essential to supplement both nutritional and industrial needs of an ever-increasing African (and global) population. Before now and to our best knowledge, the previous research involved Canarium schweinfurthii Engl. fruit specific to Nigeria appear to have been more on the evaluation of seed, pulp, and essential oils (from the seed), but much less on the pulp oil. To supplement existing information, this current work has aimed to biochemically characterize the Soxhlet-extracted pulp oil of C. schweinfurthii fruit gathered from a community situated in the South-east of Nigeria. Specifically, the biochemical characterization comprised the determinations of proximate compositions, lipid peroxidation, fatty acid profile, as well as carotenoids, sterols, and tocopherols. Processing the fruit sample to pulp oil involved, among others, oven-drying, and grinding, prior to the Soxhlet extraction. Results of proximate components of C. schweinfurthii pulp oil showed the following trend: crude fat content (~ 49.32%) > carbohydrates (~ 37.93%) > moisture content (~ 8.62%) > ash content (~ 3.74%) > crude protein content (~ 0.39%) values. The lipid peroxidation attributes comprised acid (~ 23.60 mg KOH/g), peroxide (~ 33.91 mEq. O₂/kg), iodine (~ 58.3 g/100 g), and saponification (~ 138.21 mg KOH/g) values. In addition to the free (~ 13.8%), saturated (~ 9.74%), and unsaturated (~ 90.26%) fatty acids, a total of fifteen (15) fatty acid methyl esters (FAMEs) spectral peaks were found, from caprylic acid (C8:0) to lignoceric acid (C24:0). Total tocopherol concentration amounted to ~ 73 mg/100 g, which comprised α, β, γ-tocopherol, and δ-tocotrienol, with fair concentrations of carotenoids and sterols. Overall, the C. schweinfurthii pulp oil—biochemically competitive with a high concentration of unsaturated fatty acid, tocopherol, and sterol, suggests strong industrial promise.

Sustainable processes for treatment and management of seafood solid waste

Seafood processing is an important economical activity worldwide and is an integral part of the food chain system. However, their processing results in solid waste generation whose disposal and management is a serious concern. Proteins, amino acids, lipids with high amounts of polyunsaturated fatty acids (PUFA), carotenoids, and minerals are abundant in the discards, effluents, and by-catch of seafood processing waste. As a result, it causes nutritional loss and poses major environmental risks. To solve the issues, it is critical that the waste be exposed to secondary processing and valorization for recovery of value added products. Although chemical waste treatment technologies are available, the majority of these procedures have inherent flaws. Biological solutions, on the other hand, are safe, efficacious, and ecologically friendly while maintaining the intrinsic bioactivities after waste conversion. Microbial fermentation or the actions of exogenously introduced enzymes on waste components are used in most bioconversion processes. Algal biotechnology has recently developed unique technologies for biotransformation of nutrients, which may be employed as a feedstock for the recovery of important chemicals as well as biofuel. Bioconversion methods combined with a bio-refinery strategy offer the potential to enable environmentally-friendly and cost-effective seafood waste management. The refinement of these wastes through sustainable bioprocessing interventions can give rise to various circular bioeconomies within the seafood processing sector. Moreover, a techno-economic perspective on the developed solid waste processing lines and its subsequent environmental impact could facilitate commercialization. This review aims to provide a comprehensive view and critical analysis of the recent updates in seafood waste processing in terms of bioconversion processes and byproduct development. Various case studies on circular bioeconomy formulated on seafood processing waste along with techno-economic feasibility for the possible development of sustainable seafood biorefineries have also been discussed.

Sc-CO2 extraction of fish and fish by-products in the production of fish oil and enzyme

Supercritical carbon dioxide (Sc-CO2) is an alternative tool to extract lipid for the production of fish oil and enzyme from fish by-products (FBPs). In the application of Sc-CO2, this review covers sample preparation, lipid extraction operation, and characterization of fish oil and enzyme as final products. Generally, the fish samples with moisture content less than 20% and particle size less than 5 mm are considered before lipid extraction with Sc-CO2. Sc-CO2 parameters, such as pressure (P), temperature (T), extraction time (text), and flow rate (F), for simultaneous recovery of fish oil, protein, and enzyme were found to be less severe (P: 10.3-25 MPa; T: 25-45 °C, text: 20-150 min; F: 3-50 g/min) than the extraction of fish oil alone (P: 10-40 Mpa; T: 35-80 °C; text: 30-360 min; F: 1-3000 g/min). The enzyme from the Sc-CO2 defatted sample showed higher activity up to 45 U/mg due to lower denaturation of protein as compared to the organic solvent treated sample albeit both samples having similar pH (6-10) and temperature stability (20-60 °C). Overall, mild extraction of lipid from FBPs using Sc-CO2 is effective for the production of enzymes suitable in various industrial applications. Also, fish oil as a result of extraction can be produced as a health product with high polyunsaturated fatty acids (PUFAs) and low contamination of heavy metals.

Aquaculture and agriculture-by products as sustainable sources of omega-3 fatty acids in the food industry

The valorization of by-products is currently a matter of great concern to improve the sustainability of the food industry. High quality by-products derived from the food chain are omega-3 fatty acids, being fish the main source of docosahexaenoic acid and eicosapentaenoic acid. The search for economic and sustainable sources following the standards of circular economy had led to search for strategies that put in value new resources to obtain different omega-3 fatty acids, which could be further employed in the development of new industrial products without producing more wastes and economic losses. In this sense, seeds and vegetables, fruits and crustaceans by products can be an alternative. This review encompasses all these aspects on omega-3 fatty acids profile from marine and agri-food by-products together with their extraction and purification technologies are reported. These comprise conventional techniques like extraction with solvents, cold press, and wet pressing and, more recently proposed ones like, supercritical fluids fractionation and purification by chromatographic methods. The information collected indicates a trend to combine different conventional and emerging technologies to improve product yields and purity. This paper also addresses encapsulation strategies for their integration in novel foods to achieve maximum consumer acceptance and to ensure their effectiveness.

Lipid Indexes and Quality Evaluation of Omega-3 Rich Oil from the Waste of Japanese Spanish Mackerel Extracted by Supercritical CO2

Japanese Spanish mackerel (JSM) (Scomberomorus niphonius) is a marine fish species containing health-beneficial polyunsaturated fatty acids (PUFAs). In the present study, the quality of JSM by-products oils extracted by supercritical CO2 (SC-CO2) and organic solvent extraction was compared in terms of physico-chemical properties of the oils. Eicosapentaenoic acid (EPA) is one of the important polyunsaturated fatty acids present in SC-CO2-extracted skin and muscle oil 5.81 ± 0.69% and 4.93 ± 0.06%, respectively. The amount of docosahexaenoic acid (DHA) in SC-CO2-extracted skin and muscle oil was 12.56 ± 0.38% and 15.01 ± 0.28%, respectively. EPA and DHA are considered as important PUFAs for the development of brain function and the prevention of coronary heart diseases. Extracted oils showed considerable antioxidant activity. In the obtained oils, atherogenic index (AI) values varied from 0.72 to 0.93 and thrombogenic index (TI) ranged from 0.75 to 0.92, which is considered an acceptable level. Fatty acid composition, bio potentiality, thermogravimetric, and vitamin D analysis showed that oils extracted from JSM by-products can be a good source of oil for application in food, pharmaceutical and cosmetic industries. Therefore, the present research revealed the potentiality of green valorisation of S. niphonius by-products as a possible sustainable approach for targeting the era of zero waste.

Valorization of Seafood Processing Discards: Bioconversion and Bio-Refinery Approaches

The seafood industry generates large volumes of waste. These include processing discards consisting of shell, head, bones intestine, fin, skin, voluminous amounts of wastewater discharged as effluents, and low-value under-utilized fish, which are caught as by-catch of commercial fishing operations. The discards, effluents, and by-catch are rich in nutrients including proteins, amino acids, lipids containing good proportions of polyunsaturated fatty acids (PUFA), carotenoids, and minerals. The seafood waste is, therefore, responsible for loss of nutrients and serious environmental hazards. It is important that the waste is subjected to secondary processing and valorization to address the problems. Although chemical processes are available for waste treatment, most of these processes have inherent weaknesses. Biological treatments, however, are environmentally friendly, safe, and cost-effective. Biological treatments are based on bioconversion processes, which help with the recovery of valuable ingredients from by-catch, processing discards, and effluents, without losing their inherent bioactivities. Major bioconversion processes make use of microbial fermentations or actions of exogenously added enzymes on the waste components. Recent developments in algal biotechnology offer novel processes for biotransformation of nutrients as single cell proteins, which can be used as feedstock for the recovery of valuable ingredients and also biofuel. Bioconversion options in conjunction with a bio-refinery approach have potential for eco-friendly and economical management of seafood waste that can support sustainable seafood production.

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.

Extraction of protein from food waste: An overview of current status and opportunities

The chief intent of this review is to explain the different extraction techniques and efficiencies for the recovery of protein from food waste (FW) sources. Although FW is not a new concept, increasing concerns about chronic hunger, nutritional deficiency, food security, and sustainability have intensified attention on alternative and sustainable sources of protein for food and feed. Initiatives to extract and utilize protein from FW on a commercial scale have been undertaken, mainly in the developed countries, but they remain largely underutilized and generally suited for low-quality products. The current analysis reveals the extraction of protein from FW is a many-sided (complex) issue, and that identifies for a stronger and extensive integration of diverse extraction perspectives, focusing on nutritional quality, yield, and functionality of the isolated protein as a valued recycled ingredient.

Active biopackaging produced from by-products and waste from food and marine industries

The agro-food industry cannot today do without packaging to preserve and above all market its products. Plastic materials coming mainly from petrochemicals have taken a predominant place in the food packaging sector. They have become indispensable in many sectors, from fresh to frozen products, from meat and dairy products to fruit and vegetables or almost-ready meals. Plastics are cheap, their lightness reduces transport costs, and their convenience is fundamental for out-of-home catering. However, plastics pose serious end-of-life issues. The development of materials that are more respectful of the consumer and the environment has become a major issue. In addition, the agro-food industries generate significant quantities of waste or by-products that are poorly or not at all recovered. However, these contain constituents that can be extracted or transformed to be compatible with packaging uses. Many molecules from waste materials are of particular interest for the development of active packaging such as biopolymers, bioactive agents, inorganic compounds, fibers, or nano- and micro-objects. Providing bioactive functions such as antioxidants or antimicrobials can extend the shelf life of food while reducing the sophistication of plastic materials and thus improving their recycling. This article summarizes the main materials and constituents that can be recovered from waste and illustrates through several examples what could be the applications of such new, sustainable, and active packaging.

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.

Sustainable Synthesis of Omega-3 Fatty Acid Ethyl Esters from Monkfish Liver Oil

The search for economic and sustainable sources of polyunsaturated fatty acids (PUFAs) within the framework of the circular economy is encouraged by their proven beneficial effects on health. The extraction of monkfish liver oil (MLO) for the synthesis of omega-3 ethyl esters was performed to evaluate two blending systems and four green solvents in this work. Moreover, the potential solubility of the MLO in green solvents was studied using the predictive simulation software COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS). The production of ethyl esters was performed by one or two-step reactions. Novozym 435, two resting cells (Aspergillus flavus and Rhizopus oryzae) obtained in our laboratory and a mix of them were used as biocatalysts in a solvent-free system. The yields for Novozym 435, R. oryzae and A. flavus in the one-step esterification were 63, 61 and 46%, respectively. The hydrolysis step in the two-step reaction led to 83, 88 and 93% of free fatty acids (FFA) for Novozym 435, R. oryzae and A. flavus, respectively. However, Novozym 435 showed the highest yield in the esterification step (85%), followed by R. oryzae (65%) and A. flavus (41%). Moreover, selectivity of polyunsaturated fatty acids of R. oryzae lipase was evidenced as it slightly esterified docosahexaenoic acid (DHA) in all the esterification reactions tested.

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.

Extraction Methods for Obtaining Natural Blue Colorants

Background:

Blue is a color not often present in food. Even so, it is especially attractive to children. Today, most blue coloring agents used by the food industry are synthetic. With increasing health issues concern by the scientific community and the general population, there is a trend to look for natural alternatives to most synthetic products. There only exist few natural blue colorants, which are presented in a literature survey, along with the methods currently used for their recovery from natural sources. The best extraction methods and process parameters for the extraction of blue anthocyanins, iridoids and phycocyanin are discussed.

Methods:

A literature survey was conducted to detect the main sources of blue colorants found in nature. The focus was on the extraction methods used to recover such molecules, with the objective of finding efficient and environmentally safe techniques for application at industrial level, and, thus, allowing the production of natural blue colorants at scale high enough for food industry consumption.

Results:

The main natural blue colorants found in literature are anthocyanins, phycocyanin, and genipin. While anthocyanins can be recovered from a variety of plants, the source of phycocyanin are algae, and genipin can be obtained specifically from Gardenia jasminoides Ellis and Genipa americana L. Several extraction techniques have been applied to recover blue colorants from such sources, from classical methods using organic solvents, to more sophisticated technologies as ultrasoundassisted extraction, supercritical fluid extraction, pressurized liquid extraction, high-pressure extraction, and enzyme-assisted extraction.

Conclusion:

There is great potential for anthocyanins, phycocyanin and genipin use as natural food additives with health benefits, besides imparting color. However, the technologies for the colorants recovery and application are not mature enough. Therefore, this area is still developing, and it is necessary to evaluate the economic feasibility of the proposed extraction processes, along with the safety and acceptance of colored food using these additives.

Upgrading of marine (fish and crustaceans) biowaste for high added-value molecules and bio(nano)-materials

Currently, the Earth is subjected to environmental pressure of unprecedented proportions in the history of mankind. The inexorable growth of the global population and the establishment of large urban areas with increasingly higher expectations regarding the quality of life are issues demanding radically new strategies aimed to change the current model, which is still mostly based on linear economy approaches and fossil resources towards innovative standards, where both energy and daily use products and materials should be of renewable origin and 'made to be made again'. These concepts have inspired the circular economy vision, which redefines growth through the continuous valorisation of waste generated by any production or activity in a virtuous cycle. This not only has a positive impact on the environment, but builds long-term resilience, generating business, new technologies, livelihoods and jobs. In this scenario, among the discards of anthropogenic activities, biodegradable waste represents one of the largest and highly heterogeneous portions, which includes garden and park waste, food processing and kitchen waste from households, restaurants, caterers and retail premises, and food plants, domestic and sewage waste, manure, food waste, and residues from forestry, agriculture and fisheries. Thus, this review specifically aims to survey the processes and technologies for the recovery of fish waste and its sustainable conversion to high added-value molecules and bio(nano)materials.

Aquaculture and its by-products as a source of nutrients and bioactive compounds

Underutilized marine resources (e.g., algae, fish, and shellfish processing by-products), as sustainable alternatives to livestock protein and interesting sources of bioactive compounds, have attracted the attention of the researchers. Aquatic products processing industries are growing globally and producing huge amounts of by-products that often discarded as waste. However, recent studies pointed out that marine waste contains several valuable components including high-quality proteins, lipids, minerals, vitamins, enzymes, and bioactive compounds that can be used against cancer and some cardiovascular disorders. Besides, previously conducted studies on algae have shown the presence of some unique biologically active compounds and valuable proteins. Hence, this chapter points out recent advances in this area of research and discusses the importance of aquaculture and fish processing by-products as alternative sources of proteins and bioactive compounds.

Innovative Green Technologies of Intensification for Valorization of Seafood and Their by-Products

The activities linked to the fishing sector generate substantial quantities of by-products, which are often discarded or used as low-value ingredients in animal feed. However, these marine by-products are a prominent potential good source of bioactive compounds, with important functional properties that can be isolated or up-concentrated, giving them an added value in higher end markets, as for instance nutraceuticals and cosmetics. This valorization of fish by-products has been boosted by the increasing awareness of consumers regarding the relationship between diet and health, demanding new fish products with enhanced nutritional and functional properties. To obtain fish by-product-derived biocompounds with good, functional and acceptable organoleptic properties, the selection of appropriate extraction methods for each bioactive ingredient is of the outmost importance. In this regard, over the last years, innovative alternative technologies of intensification, such as ultrasound-assisted extraction (UAE) and supercritical fluid extraction (SFE), have become an alternative to the conventional methods in the isolation of valuable compounds from fish and shellfish by-products. Innovative green technologies present great advantages to traditional methods, preserving and even enhancing the quality and the extraction efficiency, as well as minimizing functional properties' losses of the bioactive compounds extracted from marine by-products. Besides their biological activities, bioactive compounds obtained by innovative alternative technologies can enhance several technological properties of food matrices, enabling their use as ingredients in novel foods. This review is focusing on analyzing the principles and the use of UAE and SFE as emerging technologies to valorize seafoods and their by-products.

Reclamation of Fishery Processing Waste: A Mini-Review

: Seafood such as fish, shellfish, and squid are a unique source of nutrients. However, many marine processing byproducts, such as viscera, shells, heads, and bones, are discarded, even though they are rich sources of structurally diverse bioactive nitrogenous components. Based on emerging evidence of their potential health benefits, these components show significant promise as functional food ingredients. Fish waste components contain significant levels of high-quality protein, which represents a source for biofunctional peptide mining. The chitin contained in shrimp shells, crab shells, and squid pens may also be of value. The components produced by bioconversion are reported to have antioxidative, antimicrobial, anticancer, antihypertensive, antidiabetic, and anticoagulant activities. This review provides an overview of the extraordinary potential of processing fish and chitin-containing seafood byproducts via chemical procedures, enzymatic and fermentation technologies, and chemical modifications, as well as their applications.

Production and Refinement of Omega-3 Rich Oils from Processing By-Products of Farmed Fish Species

In this study, the effect of a four-stage chemical refining process (degumming, neutralization, bleaching, deodorization) on the quality parameters, fatty acid composition and volatile compounds of crude oils produced from processing by-products of farmed fish species (tuna, seabass and gilthead seabream) was evaluated. The quality of the oils was compared to commercially available cod liver oil on the basis of free fatty acid, peroxide value, p-anisidine, total oxidation (TOTOX), thiobarbituric acid reactive species (TBARS), oxidative stability at 80, 100 and 120 °C, tocopherol content, and volatile components, while the fatty acid profile and the proportion of polyunsaturated fatty acids (PUFAs) were used as an indicator of the nutritional values of fish oils. Quality parameters of the studied oils and oil oxidative stability were enhanced with refining and were within the limits recommended for fish oils without the loss of PUFAs. In tuna by-product refined oils, the proportion of PUFAs was over 40%, with 30% of eicosapentaenoic and docosahexaenoic fatty acids. The volatile compounds of the oils were quantified (in mg/kg) and major components were 2,4-heptadienal, pentadecane, 2,4-decadienal, 2,4-nonadienal and dodecane. The use of aquaculture by-products as an alternative source for fish oil production could contribute to a more sustainable and profitable aquaculture production, providing economic benefits for the producers and setting new standards for a fish by-product disposal strategy.

Marine Waste Utilization as a Source of Functional and Health Compounds

Consumer demand for convenience has led to large quantities of seafood being value-added processed before marketing, resulting in large amounts of marine by-products being generated by processing industries. Several bioconversion processes have been proposed to transform some of these by-products. In addition to their relatively low value conventional use as animal feed and fertilizers, several investigations have been reported that have demonstrated the potential to add value to viscera, heads, skins, fins, trimmings, and crab and shrimp shells by extraction of lipids, bioactive peptides, enzymes, and other functional proteins and chitin that can be used in food and pharmaceutical applications. This chapter is focused on reviewing the opportunities for utilization of these marine by-products. The chapter discusses the various products and bioactive compounds that can be obtained from seafood waste and describes various methods that can be used to produce these products with the aim of highlighting opportunities to add value to these marine waste streams.