Production of omega-3 polyunsaturated fatty acid concentrates: A review

Metabolic Engineering of Yarrowia lipolytica for Conversion of Waste Cooking Oil into Omega-3 Eicosapentaenoic Acid

Omega-3 polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA, C20:5), are crucial dietary fats known for their numerous health benefits. However, traditional sources of EPA, like fish oil, raise sustainability and environmental concerns, underscoring the need for alternative production methods. The engineered oleaginous yeast Yarrowia lipolytica has emerged as a promising candidate for sustainable production of EPA. This study explores the efficient production of EPA with an earlier engineeredY. lipolytica strain Y8412, utilizing waste cooking oil (WCO) as an alternative carbon source. While cofeeding WCO resulted in increased total lipid content, it also caused an increase in intracellular free fatty acid (FFA) levels, which can be toxic to cells and reduce EPA synthesis. To solve this issue, we first overexpressed FAA1 and GPD1 genes converting excess FFAs into triglycerides (TAGs). Additionally, we knocked out TGL3/4 genes, which encode lipases linked to lipid bodies, to minimize the degradation of TAGs back into FFAs. The modified strains significantly reduced intracellular FFA levels and improved EPA production. Notably, the TGL4 knockout strain Y8412T4- showed 57% increase in EPA production titer and nearly 50% increase in carbon conversion yield compared to the parental strain Y8412 fed with glucose only. These findings suggest that preventing TAG degradation by knocking out TGL4 is an effective approach for enhanced EPA production when WCO is used to partially replace glucose as the carbon source. This study offers an effective engineering strategy for low-cost, high-yield, and sustainable production of omega-3 fatty acids from waste feedstocks.

Impact of technological processing on the bioavailability of omega-3 fatty acids in fish oil: a review

Both the growing prevalence of chronic diseases and the consumer's health awareness have increased the intake of fish oil supplements since it is rich in omega-3. However, the proposed preventive or therapeutic effects of fish oil in different diseases are inconsistent, partially because processing affects on omega-3 stability and bioavailability. Thus, this review aims to describe the influence of fish oil processing on the omega-3 bioavailability in humans. This review illustrates how fish oil is obtained and processed, summarizes how omega-3 bioavailability is assessed, and describes how the molecular form and formulation may modulate their bioavailability. The bioavailability of omega-3 depends on the processing and formulation of fish oil, which influences the acceptability and stability of the final product. Currently, omega-3 is more bioavailable when ingested as free fatty acid, followed by triglyceride, and lastly as ethyl ester. Due to their high susceptibility to oxidation and preliminary findings, administering omega-3 in the form of triglyceride may be the most suitable to maximize bioavailability. Additionally, formulations that promote self-emulsification of fish oil show promise, though more human studies are needed to support these results. These results could optimize the bioavailability of omega-3 and the potential health-related applications of fish oil.

Enrichment of pasteurized skim milk with grape seed oil multilayer emulsions: Investigating the effect of emulsion layers on physicochemical, microbial, and sensory characteristics

Cow's milk is a nutritionally valuable food, although it lacks essential unsaturated fatty acids. Enriching milk with these fatty acids can reduce risks associated with cholesterol and saturated fats while meeting consumers' dietary needs. Grape seed oil (GSO), which is rich in omega-6 and omega-9 fatty acids, is one potential additive to replace milk fat and increase the unsaturated fat content. However, these essential unsaturated fatty acids are hydrophobic, making them difficult to dissolve in water, and are prone to oxidation, which can negatively affect the aroma and flavor of the milk. The layer-by-layer emulsion method is a promising approach to mitigate these challenges. This study investigated the enrichment of pasteurized skim milk with optimized multilayer emulsions of GSO and evaluated the physicochemical, microbial, and sensory characteristics of the milk over a storage period of 7 d at 4°C. Results indicated that single- and triple-layer emulsions remained stable within the milk matrix, but the 2-layer emulsion became unstable by d 3 of storage. During storage, acidity increased in all samples (from 0.16 to 0.44, 0.24 to 0.48, and 0.2 to 0.36 for single-, double-, and triple-layer emulsions, respectively), as did viscosity (from 1.53 to 1.9, 1.55 to 2.2, and 1.46 to 1.78 mPa·s, respectively), total microorganism count, peroxide value (from 5.52 to 17.6, 4.7 to 19.38, and 3.09 to 10.3 mEq/kg oil, respectively), and thiobarbituric acid index (from 0.43 to 0.52, 0.44 to 0.63, and 0.39 to 0.47 mg malondialdehyde/kg of oil, respectively). The pH values decreased slightly across all samples (from 6.6 to 6.5). No mold, yeast, or coliforms were detected in any sample throughout the study. Overall, the use of bioactive compounds such as essential fatty acids through milk enrichment can greatly enhance the quality of widely consumed dairy products.

In silico analysis of non-conventional gene targets for genetic interventions to enhance fatty acid production: a review

Since the 1990s, fatty acids (FA) have drawn significant industrial attention due to their diverse applications creating a demand for biological systems capable of producing high FA titers. While various strategies have been explored to achieve this, many of the conventional approaches rely on extensive genetic manipulations, which often result in strain instability, thus limiting its potential to yield better FA titers. Moreover, stresses such as pH, osmotic, and oxidative imbalances generated during FA production aggravate these challenges, further limiting FA titers. Under stress conditions, the cellular system responds by regulating stress-response proteins to bring about homeostasis. Recent findings suggest that transmembrane proteins, regulators of two-component systems, and cytoplasmic regulators can be strategically leveraged to address the problems related to stress-induced strain instability. Thus, non-conventional genetic targets, like chaperones (e.g., heat shock proteins) and DNA-binding transcriptional regulators (e.g., RcdA), which are not directly involved in FA metabolism, represent promising candidates to enhance strain stability and FA yields. Tools like Opt-Box and Weighted Gene Co-expression Network Analysis (WGCNA) serve as excellent platforms for understanding the cross-talk between these regulators and downstream enzymes. This review emphasizes the need for a shift towards identifying novel genetic targets by employing advanced in silico analysis and explains several molecular techniques that can aid in strain construction. Lastly, it discusses certain non-conventional gene targets that can help to overcome strain instability arising due to various stresses generated during/due to FA production.

Diverse uses of valuable seafood processing industry waste for sustainability: a review

Seafoods are rich in untapped bioactive compounds that have the potential to provide novel ingredients for the development of commercial functional foods and pharmaceuticals. Unfortunately, a large portion of waste or discards is generated in commercial processing setups (50-80%), which is wasted or underutilized. These by-products are a rich source of novel and valuable biomolecules, including bioactive peptides, collagen and gelatin, oligosaccharides, fatty acids, enzymes, calcium, water-soluble minerals, vitamins, carotenoids, chitin, chitosan and biopolymers. These fish components may be used in the food, cosmetic, pharmaceutical, environmental, biomedical and other industries. Furthermore, they provide a viable source for the production of biofuels. As a result, the current review emphasizes the importance of effective by-product and discard reduction techniques that can provide practical and profitable solutions. Recognizing this, many initiatives have been initiated to effectively use them and generate income for the long-term sustainability of the environment and economic framework of the processing industry. This comprehensive review summarizes the current state of the art in the sustainable valorisation of seafood by-products for human consumption. The review can generate a better understanding of the techniques for seafood waste valorisation to accelerate the sector while providing significant benefits.

Spectrophotometric assay for the screening of selective enzymes towards DHA and EPA ethyl esters hydrolysis

Polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), hold notable significance due to their pharmaceutical relevance. Obtaining PUFAs from diverse sources like vegetables, fish oils, and algae poses challenges due to the mixed fatty acid (FA) composition. Therefore, focusing on particular FAs necessitates purification and resolution processes. To address this, we propose a continuous assay for screening lipases selective for ethyl EPA (E-EPA) or ethyl DHA (E-DHA). Utilizing microplate spectrophotometry, the method enables quantification of liberated fatty acids from ethyl esters (E-EPA or E-DHA). This involves assessing enzyme selectivity by measuring the release of FAs through p-nitrophenolate protonation, either separately for each substrate or in competition with a reference substrate, resorufin acetate. Ten lipases underwent screening, revealing Burkholderia cepacia lipase's (BCL) preference for ethyl DHA hydrolysis (E-EPA/E-DHA = 0.82 ± 0.07 and the lipase selectivity ratio (S) for E-EPA/E-DHA = 0.13 ± 0.04) and Candida antarctica lipase B's (CALB) high specific activity towards both E-EPA and E-DHA (531.14 ± 37.76 and 281.79 ± 2.79 U/mg, respectively) and E-EPA preference (E-EPA/E-DHA = 1.86 ± 0.15 and S E-EPA/E-DHA = 2.59±0.15). Candida rugosa recombinant isoform 4 (rCRLip4) and commercial Candida rugosa lipase (CRL) exhibited significant preference for E-EPA hydrolysis (E-EPA/E-DHA = 2.18 ±0.51 and 2.26 ±0.36, respectively; and S E-EPA/E-DHA = 7.59 ± 1.59 and 7.88 ± 2.13, respectively). Docking analyses of rCRLip4, BCL, and CALB demonstrated no statistically significant differences in activation energies or distances to the catalytic serine; however, they agreed with the experimental results. These findings suggest potential mutagenesis or directed evolution strategies for CALB to enhance E-EPA selectivity, with rCRLip4 emerging as a promising candidate for further investigation. This assay offers a valuable tool for identifying lipases with desired substrate selectivity, with broad implications for pharmaceutical and biotechnological applications.

Preservative Effect of Alga Flour Extract on Frozen Horse Mackerel (Trachurus trachurus) Lipids

The aim of this study was to investigate the preservative properties of alga Gelidium sp. flour when included in the glazing medium employed for the frozen storage (-18 °C) of horse mackerel (Trachurus trachurus). Different concentrations (low, medium, and high) of an aqueous extract were tested and compared to a control water-glazing condition. Quality changes (lipid oxidation and hydrolysis, fatty acid (FA) profile, and trimethylamine (TMA) formation) were determined after 3- and 6-month storage periods. A general quality loss (lipid oxidation with hydrolysis development and TMA formation) with the frozen storage period was detected in all samples. The presence of an alga flour (AF) extract in the glazing medium led to a lower (p < 0.05) TBARS and fluorescent compound formation and to higher (p < 0.05) polyene values in frozen fish. Furthermore, a preserving effect on free fatty acids was detected in AF-treated fish. On the contrary, the AF-glazing treatment did not affect (p > 0.05) the TMA formation and the total n3/total n6 FA ratio. In general, preservative effects were found to be higher in frozen fish corresponding to the medium concentration tested. Current results show the potential of Gelidium sp. flour as a natural source of preservative hydrophilic compounds for the quality enhancement of frozen horse mackerel.

Novel Encapsulation Approaches in the Functional Food Industry: With a Focus on Probiotic Cells and Bioactive Compounds

Bioactive substances can enhance host health by modulating biological reactions, but their absorption and utilization by the body are crucial for positive effects. Encapsulation of probiotics is rapidly advancing in food science, with new approaches such as 3D printing, spray-drying, microfluidics, and cryomilling. Co-encapsulation with bioactives presents a cost-effective and successful approach to delivering probiotic components to specific colon areas, improving viability and bioactivity. However, the exact method by which bioactive chemicals enhance probiotic survivability remains uncertain. Co-crystallization as an emerging encapsulation method improves the physical characteristics of active components. It transforms the structure of sucrose into uneven agglomerated crystals, creating a porous network to protect active ingredients. Likewise, electrohydrodynamic techniques are used to generate fibers with diverse properties, protecting bioactive compounds from harsh circumstances at ambient temperature. Electrohydrodynamic procedures are highly adaptable, uncomplicated, and easily expandable, resulting in enhanced product quality and functionality across various food domains. Furthermore, food byproducts offer nutritional benefits and technical potential, aligning with circular economy principles to minimize environmental impact and promote economic growth. Hence, industrialized nations can capitalize on the growing demand for functional foods by incorporating these developments into their traditional cuisine and partnering with businesses to enhance manufacturing and production processes.

Effects of Dietary Lipid Levels on the Growth, Muscle Fatty Acid and Amino Acid Composition, Antioxidant Capacity, and Lipid Deposition in Mirror Carp (Cyprinus carpio)

In fish, increasing the crude lipid level of feed can save protein and improve feed utilization. Mirror carp (Cyprinus carpio) is one of the most widely farmed fish species in the world. In this study, mirror carp larvae were fed isonitrogenous diets with different lipid levels (3%, 5%, 7%, 9%, 11%, and 13%). The rearing trial lasted for eight weeks. The results revealed that when the fat content was 9%, the AWGR, WGR, and FCR were highest, whereas FCR was lowest. The AWGR was correlated with the dietary lipid level, and the regression equation was y = -2.312x2 + 45.01x + 214.49. Compared with those in the control group, the T-CHO and TG contents were significantly greater in the 13% lipid content groups and significantly lower in the 9% lipid content groups (p < 0.05). In terms of muscle quality, the contents of MUFAs, PUFAs, and DHA + EPA were significantly greater than those in the other experimental groups (p < 0.05). Oil red O staining revealed a lipid content of 13% with severe fat deposition. In addition, the results of the analysis of antioxidant enzyme activity revealed that the activities of GSH, CAT and T-AOC were significantly greater at the 9% lipid content, and that the MDA content was significantly greater at the 13% lipid content (p < 0.05). Similarly, the mRNA levels of GH, IGF-I, FAS, and LPL were significantly highest at a lipid level of 9% (p < 0.05). The above results revealed that the optimal dietary lipid requirement for the fast growth of mirror carp (6.86 ± 0.95 g) was 9.74% on the basis of nonlinear regression analysis of the AWGR. The dietary lipid level (9%) improved the growth, stress resistance, and lipid utilization of mirror carp to a certain extent.

Biochemical profile of Scenedesmus isolates, with a main focus on the fatty acid profile

Biochemical characterization of new microalgal strains that are isolated from diverse environmental conditions is an important starting point for the establishment of high-quality feedstock for nutraceutical and pharmaceutical applications. In this research study, the biochemical composition of three Iranian native subspecies of Scenedesmus microalgae (Scenedesmus obliquus, Scenedesmus bijugusi, and Scenedesmus sp.), with the main focus on fatty acid composition, was studied. The results showed that the strain Scenedesmus bijugusi had the highest biomass productivity (48 g/L/d), biomass (0.73%), carbohydrate (13.97%), fat (16.27%), protein (44.04%), chlorophyll-a (6.32 mg/g), and carotenoids (3.7 mg/g). The lipid profile also revealed that S. obliquus had the highest percentage of polyunsaturated fatty acid (46.52%), ratio of ∑n-3/∑n-6 (5.96), ratio of polyunsaturated fatty acid to saturated fatty acid (PUFA/SAF) (1.18), α-linolenic acid (22.74%), hypocholesterolemia index (1.61), and low atherogenic index (0.34). S. bijugusi and S. obliquus, thus, showed a great promise in nutraceutical and pharmaceutical applications due to their appropriate high productivity, biopigment, protein, lipid, antioxidant activity, long-chain polyunsaturated fatty acids, and α-linolenic acid.

Alternate solvent for soybean oil extraction based on extractability and membrane solvent recovery

Ethyl acetate, acetone, 2-propanol, 1-propanol, and ethanol were screened among the class 3 category solvents as an alternative to hexane based on operational and occupational safety and bio-renewability potential. All five solvents exhibited higher extractability (22.3 to 23.2%) than hexane (21.5%) with soybean flour. Additionally, there was no significant difference in the fatty acid and triacylglycerol (TAG) composition of the oils extracted using alternate solvents and hexane, indicating the oil quality was not affected. More importantly, ethyl acetate (2.1%) resulted in a marginally higher yield of TAG, while 2-propanol showed a nearly equal yield to hexane. Further, membrane desolventizing was attempted to mitigate the limitations of higher thermal energy requirements. One of the polydimethylsiloxane membranes exhibited good selectivity (TAG rejection 85.8%) and acceptable flux (59.3 L·m-2·h-1) with an ethyl acetate miscella system. Under plant-simulated recirculation conditions, a two-stage membrane process reduced the oil content in permeate to 2.5%. The study revealed that ethyl acetate could potentially replace hexane, considering its higher TAG extractability and suitability for the membrane-augmented solvent recycling process in the extraction plants.

Biochemical profile of Dunaliella isolates from different regions of Iran with a focus on pharmaceutical and nutraceutical potential applications

This study was conducted to evaluate three species of Dunaliella microalgae (Dunaliella salina, Dunaliella viridis, and Dunaliella sp.) indigenous to Iran as new sources of natural chemical and bioactive compounds for exploring pharmaceutical and nutraceutical potential applications. The results showed that the fat, carbohydrate (mono- and di-saccharide), dietary fiber, and protein content of Dunaliella were in the range of 13.19-25.02, 7.59-12.37, 42.10-48.82, and 17.68-22.50 (%), respectively. Dunaliella salina contained a pigment fraction of 11.50%, which was largely composed of carotenoid (7.41%) and chlorophyll (4.09%). Antioxidant capacity and inhibition of 2,2-diphenyl-1-1-picrylhydrazyl (DPPH) of Dunaliella salina were 34.54 mg/1000 g and 55.63%, respectively. The lipid profile also revealed that three isolated Dunaliella are remarkable sources of polyunsaturated fatty acids (25.42%-40.13%). Further, the ratios of ∑n-3/∑n-6 (2.79%), docosahexaenoic acid (6.15%), and eicosapentaenoic acid (11.26%) were the highest in Dunaliella salina. The results, thus, proved that Dunaliella spp., especially Dunaliella salina (IBRC-M 50030), which originates from a lake in Semnan province, Iran, has potential applications in the food and pharmaceutical industries due to its appropriate biopigment, protein, lipid, antioxidant activity, long-chain polyunsaturated fatty acids, docosahexaenoic acid, and eicosapentaenoic acid.

Marine-Derived Lipases for Enhancing Enrichment of Very-Long-Chain Polyunsaturated Fatty Acids with Reference to Omega-3 Fatty Acids

Omega-3 fatty acids are essential fatty acids that are not synthesised by the human body and have been linked with the prevention of chronic illnesses such as cardiovascular and neurodegenerative diseases. However, the current dietary habits of the majority of the population include lower omega-3 content compared to omega-6, which does not promote good health. To overcome this, pharmaceutical and nutraceutical companies aim to produce omega-3-fortified foods. For this purpose, various approaches have been employed to obtain omega-3 concentrates from sources such as fish and algal oil with higher amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Among these techniques, enzymatic enrichment using lipase enzymes has gained tremendous interest as it is low in capital cost and simple in operation. Microorganism-derived lipases are preferred as they are easily produced due to their higher growth rate, and they hold the ability to be manipulated using genetic modification. This review aims to highlight the recent studies that have been carried out using marine lipases for the enrichment of omega-3, to provide insight into future directions. Overall, the covalent bond-based lipase immobilization to various support materials appears most promising; however, greener and less expensive options need to be strengthened.

Reversed-Phase Medium-Pressure Liquid Chromatography Purification of Omega-3 Fatty Acid Ethyl Esters Using AQ-C18

Omega-3 fatty acids are in high demand due to their efficacy in treating hypertriglyceridemia and preventing cardiovascular diseases. However, the growth of the industry is hampered by low purity and insufficient productivity. This study aims to develop an efficient RP-MPLC purification method for omega-3 fatty acid ethyl esters with high purity and capacity. The results indicate that the AQ-C18 featuring polar end-capped silanol groups outperformed C18 and others in retention time and impurity separation. By injecting pure fish oil esters with a volume equivalent to a 1.25% bed volume on an AQ-C18 MPLC column using a binary isocratic methanol-water (90:10, v:v) mobile phase at 30 mL/min, optimal omega-3 fatty acid ethyl esters were obtained, with the notable purity of 90.34% and a recovery rate of 74.30%. The total content of EPA and DHA produced increased from 67.91% to 85.27%, meeting the acceptance criteria of no less than 84% set by the 2020 edition of the Pharmacopoeia of the People's Republic of China. In contrast, RP-MPLC significantly enhanced the production efficiency per unit output compared to RP-HPLC. This study demonstrates a pioneering approach to producing omega-3 fatty acid ethyl esters with high purity and of greater quantity using AQ-C18 RP-MPLC, showing this method's significant potential for use in industrial-scale manufacturing.

Characterization of fatty acid forms using benchtop NMR in omega-3 oil supplements

Omega-3 fatty acid supplements, such as fish oil and plant-based oils, have gained popularity because of their potential health benefits. However, the quality and composition of these supplements can vary widely, particularly in terms of the two main forms of omega-3 fatty acids: triacylglycerols (TAGs) and ethyl esters (EEs). TAGs are the natural form found in fish oil but are prone to oxidation, whereas EEs are more stable but less well absorbed by the body. Differentiating between these forms is crucial for assessing the efficacy and tolerance of omega-3 supplements. This article describes a novel approach to differentiate between TAG and EE forms of omega-3 fatty acids in dietary supplements, utilizing a 60-MHz benchtop nuclear magnetic resonance (NMR) spectrometer. The proposed method using 1H and 1H-1H COSY NMR provides a quick and accurate approach to screen the forms of omega-3 fatty acids and evaluate their ratios. The presence of diacylglycerol (DAGs) in some supplements was also highlighted by this method and adds some information about the process used (i.e., esterification/enrichment). The affordability and user-friendliness of benchtop NMR equipment make this method feasible for food processing companies or quality control laboratories. In this study, 24 oil supplements were analyzed using NMR analysis in order to demonstrate the potential of this method for the differentiation of TAG and EE forms in omega-3 supplements.

Biochemical characterization of lipid metabolic genes of Aurantiochytrium limacinum

Docosahexaenoic acid (DHA) is known to have numerous health benefits and immense dietary value. There is a pressing need to have a deeper understanding of DHA metabolism. Acyl CoA: Diacylglycerol Acyltransferase (DGAT) is an important enzyme of lipid anabolism and an essential piece of the puzzle. Aurantiochytrium limacinum, a primary producer of DHA, is a good model for studying DHA metabolism. Thus, we aimed to investigate important lipid metabolic genes from A. limacinum. We cloned four putative DGATs (DGAT2a, DGAT2b, DGAT2c, and DGAT2d) from A. limacinum and performed detailed in vivo and in vitro characterization. Functional characterization showed that not all the studied genes exhibited DGAT activity. DGAT2a and DGAT2d conferred DGAT activity whereas DGAT2b showed wax synthase (WS) activity and DGAT2c showed dual function of both WS and DGAT. Based on their identified function, DGAT2b and DGAT2c were renamed as AlWS and AlWS/DGAT respectively. DGAT2a was found to exhibit a preference for DHA as a substrate. DGAT2d was found to have robust activity and emerged as a promising candidate for genetic engineering aimed at increasing oil yield. The study enriches our knowledge of lipid biosynthetic enzymes in A. limacinum, which can be utilized to design suitable application strategies.

1H NMR-based metabolomics study of the lipid profile of omega-3 fatty acid supplements and some vegetable oils

Omega-3 fatty acids, which consist of alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), are a type of polyunsaturated fatty acids that are crucial for enhancing human health. These three omega-3s are regarded as vital dietary nutrients because it cannot synthesize them on its own. Therefore, they must be obtained through dietary sources. On the other hands, there are concerns regarding the quality and quantity of omega-3 in dietary sources and supplements. In this study, 1H NMR spectroscopy and multivariate analysis were harnessed for non-destructive profiling of fatty acids in commercially available omega-3 supplements and plant-based oils. Results disclosed substantial disparities in omega-3 content from 8 to over 50 %, with some revealing unexpected adulteration. Notably, in one fish oil sample DHA could not be detected indicating the possibility of adulteration. Additionally, the research delineated the fatty acid composition of plant-based oils, emphasizing variations in alpha-linolenic acid (ALA) and linoleic acid (LA) content among flaxseed, chia seed, and walnut oils. Chia seeds emerged as a rich source of ALA (57-65 %mol), while walnuts contained considerable LA (44-53 % mol). The findings emphasize the power of metabolomics as a rapid and affordable tool for finding omega-3 fatty acids content and adulteration in commercial dietary products.

Biotechnological production of omega-3 fatty acids: current status and future perspectives

Omega-3 fatty acids, including alpha-linolenic acids (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), have shown major health benefits, but the human body's inability to synthesize them has led to the necessity of dietary intake of the products. The omega-3 fatty acid market has grown significantly, with a global market from an estimated USD 2.10 billion in 2020 to a predicted nearly USD 3.61 billion in 2028. However, obtaining a sufficient supply of high-quality and stable omega-3 fatty acids can be challenging. Currently, fish oil serves as the primary source of omega-3 fatty acids in the market, but it has several drawbacks, including high cost, inconsistent product quality, and major uncertainties in its sustainability and ecological impact. Other significant sources of omega-3 fatty acids include plants and microalgae fermentation, but they face similar challenges in reducing manufacturing costs and improving product quality and sustainability. With the advances in synthetic biology, biotechnological production of omega-3 fatty acids via engineered microbial cell factories still offers the best solution to provide a more stable, sustainable, and affordable source of omega-3 fatty acids by overcoming the major issues associated with conventional sources. This review summarizes the current status, key challenges, and future perspectives for the biotechnological production of major omega-3 fatty acids.

Refined mackerel oil increases hepatic lipid accumulation and reduces choline and choline-containing metabolites in the liver tissue in mice fed a Western diet

In this study, we aimed to evaluate the impact of consuming refined mackerel oil (MO) from rest raw material on hepatic fat accumulation, glucose tolerance, and metabolomic changes in the liver from male C57BL/6N mice. The mice were fed either a Western diet (WD) or a chow diet, with 30 g or 60 g MO per kg of diet (3% or 6%) for 13 weeks. Body weight, energy intake, and feed efficiency were monitored throughout the experiment. A glucose tolerance test was conducted after 11 weeks, and metabolomic analyses of the liver were performed at termination. Inclusion of MO in the WD, but not in the chow diet, led to increased liver weight, hepatic lipid accumulation, elevated fasting blood glucose, reduced glucose tolerance, and insulin sensitivity. Hepatic levels of eicosapentaenoic and docosahexaenoic acid increased, but no changes in levels of saturated and monounsaturated fatty acids were observed. The liver metabolomic profile was different between mice fed a WD with or without MO, with a reduction in choline ether lipids, phosphatidylcholines, and sphingomyelins in mice fed MO. This study demonstrates that supplementing the WD, but not the chow diet, with refined MO accelerates accumulation of hepatic fat droplets and negatively affects blood glucose regulation. The detrimental effects of supplementing a WD with MO were accompanied by increased fat digestibility and overall energy intake, and lower levels of choline and choline-containing metabolites in liver tissue.

Soft-capsule formulation of a re-esterified triglyceride omega-3 employing self-emulsifying technology and bioavailability evaluation in healthy volunteers

Despite the superior clinical efficacy of the re-esterified triglyceride (rTG) form compared to the ethylester form, few studies have been conducted on improving the bioavailability of the rTG form of omega-3 oil. The aim of study was to evaluate the effect of self emulsifying formulation on the improvement of bioavailability of rTG form of omega-3 oil. To develop a re-esterified triglyceride (rTG) soft capsule, an rTG-loaded self-emulsifying delivery system (SEDS) was designed using coconut oil, polysorbate 80, and lecithin. Candidate formulations were designed from a phase-diagram study and optimal SEDS formulations containing 85% of high omega-3 (ω-3) oils were screened from the evaluation of droplet size distribution, measurement of oil floating area and emulsion turbidity. The selected, optimized rTG SEDS formulation was filled into a soft capsule (NOVASEDS) and applied to a sequence-randomized, double-blind, single-dose, and two-way crossover clinical study (n = 44), and the the bioavailability of NOVASEDS was compared with that of a 'raw' rTG capsule (rTG OMEGA3) as control. The droplet size (D50) formed from the candidate formulations was approximately 30-45 μm, and the optimal formulation showed a unimodal particle distribution with the smallest oil floating area and small changes in turbidity after 24 h. Cmax and AUC from 0 to 24 h for NOVASEDS, calculated from docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and as the sum of DHA and EPA, were significantly higher (P < 0.05) than corresponding values for rTG OMEGA3. In conclusion, NOVASEDS formulated by SEDS technology enabled the manufacture of a high rTG payload soft capsule with improved bioavailability in human subjects.

Low-Toxicity Solvents for the Extraction of Valuable Lipid Compounds from Octopus (Octopus vulgaris) Waste

This study focused on the recovery of valuable lipid compounds from octopus (Octopus vulgaris) by-products. Extraction conditions of total lipids (TLs), phospholipids (PLs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) were optimized by employing a Simplex-Lattice design; for it, different relative concentrations of three low-toxicity solvents (ethanol, acetone, and ethyl acetate) were considered. The optimization process was also addressed in reference to fatty acid (FA) ratios (total polyunsaturated FAs/total saturated FAs and total ω3 FAs/total ω6 FAs). The variance analysis of multiple regression data demonstrated that the quadratic model was significant (p < 0.05) for TL, PL, and DHA values and the ω3/ω6 ratio. As a result, the following optimized values were obtained: 113.8 g·kg-1 dry by-products (TLs), 217.3 g·kg-1 lipids (PLs), 22.55 g·100 g-1 total FAs (DHA), and 3.70 (ω3/ω6 ratio). According to the model developed, optimized values were shown to correspond to the following relative solvent concentrations (ethanol/acetone/ethyl acetate): 0.46/0.00/0.54, 0.93/0.07/0.00, 0.83/0.17/0.00, and 0.64/0.00/0.36, respectively. Comparison to yields obtained by the conventional chloroform/methanol method was carried out. A novel strategy based on the employment of low-toxicity solvents is proposed for the extraction of valuable lipid constituents from octopus waste. A different solvent ratio would be necessary according to the lipid compound concerned.

Microcapsules of Sacha Inchi seed oil (Plukenetia volubilis L.) obtained by spray drying as a potential ingredient to formulate functional foods

Sacha Inchi seed oil (SIO) is rich in omega 3, 6, and 9 fatty acids with important health benefits, but is temperature sensitive. Spray drying is a technology that improves the long-term stability of bioactive compounds. This work aimed to study the effect of three different homogenization techniques on some physical properties and bioavailability of microcapsules of Sacha Inchi seed oil (SIO) emulsions obtained by spray drying. Emulsions were formulated with SIO (5%, w/w), maltodextrin:sodium caseinate as wall material (10%, w/w; 85:15), Tween 20 (1%, w/w) and Span 80 (0.5%, w/w) as surfactants and water up to 100% (w/w). Emulsions were prepared using high-speed (Dispermat D-51580, 18,000 rpm, 10 min), conventional (Mixer K-MLIM50N01, Turbo speed, 5 min), and ultrasound probe (Sonics Materials VCX 750, 35% amplitude, 750 W, 30 min) homogenization. SIO microcapsules were obtained in a Mini Spray B-290 (Büchi) using two inlet temperatures of the drying air (150 and 170 °C). Moisture, density, dissolution rate, hygroscopicity, drying efficiency (EY), encapsulation efficiency (EE), loading capacity, and oil release in digestive fluids in vitro were studied. Results showed that the microcapsules obtained by spray-drying had low moisture values and high encapsulation yield and efficiency values (greater than 50% and 70%, respectively). The thermogravimetric analysis indicates that heat protection was assured, enhancing the shelf life and the ability to withstand thermal food processing. Results suggest that spray-drying encapsulation could be a suitable technology to successfully microencapsulate SIO and enhance the absorption of bioactive compounds in the intestine. This work highlights the use of Latin American biodiversity and spray drying technology to ensure the encapsulation of bioactive compounds. This technology represents an opportunity for the development of new functional foods, improving the safety and quality of conventional foods.

Prospective life cycle assessment for the full valorization of anchovy fillet leftovers: The LimoFish process

Prospective life cycle assessment models were developed and applied at the laboratory and industrial scale with the aim to evaluate the environmental burdens associated with the LimoFish process used to produce the fish oil "AnchoiOil", the new organic fertilizer "AnchoisFert" or biogas (by means of anaerobic digestion) after treatment of anchovy fillet leftovers (AnLeft) with agro-solvent d-limonene. Potential impacts for climate change and freshwater eutrophication were estimated at 29.1 kg CO2 eq/kg AnLeft and 1.7E-07 kg PO4 eq/kg AnLeft at laboratory scale, and at 1.5 kg CO2 eq/kg AnLeft and 2.2E-07 kg PO4 eq/kg AnLeft at industrial scale. Electricity consumption is the main contributor to the environmental impact of the process and plays a significant role in the production of d-limonene, for which cold pressing extraction would reduce the related impacts by ∼ 70 %. The use of the solid by-product as organic fertilizer or input to anaerobic digestion would provide additional environmental benefits to the process. The LimoFish process is a successful example of a low impacting strategy to reduce the demand for natural resources and maximize the application of the circular economy principles in the fishing industry.

Recent Advances in the Microencapsulation of Essential Oils, Lipids, and Compound Lipids through Spray Drying: A Review

In recent decades, the microcapsules of lipids, compound lipids, and essential oils, have found numerous potential practical applications in food, textiles, agricultural products, as well as pharmaceuticals. This article discusses the encapsulation of fat-soluble vitamins, essential oils, polyunsaturated fatty acids, and structured lipids. Consequently, the compiled information establishes the criteria to better select encapsulating agents as well as combinations of encapsulating agents best suited to the types of active ingredient to be encapsulated. This review shows a trend towards applications in food and pharmacology as well as the increase in research related to microencapsulation by the spray drying of vitamins A and E, as well as fish oil, thanks to its contribution of omega 3 and omega 6. There is also an increase in articles in which spray drying is combined with other encapsulation techniques, or modifications to the conventional spray drying system.

Antioxidative capacity of microalgal carotenoids for stabilizing n-3LC-PUFA rich oil: Initial quantity is key

The health-beneficial long-chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA) are easily affected by the undesired process of lipid oxidation in fish oil, while being stable in the lipid extracts of photoautotrophic microalgae. The current research investigates the role of carotenoids by evaluating the oxidative stability of mixtures of fish oil with total lipid extracts of two different microalgae (Phaeodactylum and Isochrysis) throughout an accelerated storage experiment of 4 weeks at 37 °C. A clear separation between oxidatively stable and oxidatively unstable mixtures was observed for which the initial amount of carotenoids relative to the amount of n-3LC-PUFA was a good indicator. The lipid class composition, clearly differing between the two algae, was probably of minor influence. The antioxidative role of fucoxanthin, and diatoxanthin and β-carotene as minor carotenoids, was illustrated by their gradual degradation throughout storage. However, when their initial contents were too low, this role could not be exerted leading to thorough lipid oxidation.

Long-Chain Polyunsaturated Fatty Acids Effects on Cardiovascular Risk in Childhood: A Narrative Review

Long-chain polyunsaturated fatty acids (LCPUFAs) are semi-essential fatty acids widely studied in adult subjects for their healthy-heart effects, especially on secondary prevention in patients who already experienced a cardiac event. LCPUFAs consumption is safe, without adverse effects, and they are usually well-tolerated; they can be taken either in foods or as nutritional supplements. LCPUFAs' positive effect on global health has been worldwide recognized also for pediatric patients. In childhood and adolescence, research has mainly focused on LCPUFAs' effects on neurodevelopment, brain and visual functions and on maternal-fetal medicine, yet their cardiovascular effects in childhood are still understudied. Atherosclerosis is a multifactorial process that starts even before birth and progresses throughout life; thus, cardiovascular prevention is advisable and effective from the very first years of life. Nutritional and lifestyle interventions are the main factors that can interfere with atherosclerosis in childhood, and the consumption of specific nutrients, such as LCPUFAs, can enhance positive nutritional effects. The aim of our narrative review is to analyze the effect of LCPUFAs on cardiovascular risk factors and on cardiovascular risk prevention in developmental age, focusing on specific conditions such as weight excess and dyslipidemia.

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.

Enzymatic Synthesis Process of EPA- and DHA-Enriched Structured Acylglycerols at the sn-2 Position Starting from Commercial Salmon Oil and Concentrated by Response Surface Methodology under Supercritical Conditions

The bioavailability of n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) has shown to be greatly influenced by their location in the triacylglycerol backbone. Therefore, the synthesis of structured acylglycerols (SAcyl), which include eicosapentaenoic acids (EPAs) or docosahexaenoic acids (DHAs) at the sn-2 position, has attracted a great interest. The objective of this study was to optimize the synthesis process of a SAcyl from commercial refined salmon oil and an EPA/DHA concentrate in order to enhance the positioning of EPA and DHA in the sn-2 location of the glycerol moiety. For this purpose, immobilized lipase B from Candida antarctica (nonspecific) was used for the acidolysis process under the CO2 supercritical condition. As a result of carrying out a Draper-Lin composite design through the response surface methodology of 18 experiments, an optimized extraction including SAcyl compounds was obtained. Mass spectrometry (MALDI-TOF) analysis was employed to identify the EPA/DHA location at the sn-2 position in the resulting glycerol moiety. In the fraction obtained, an increase in the EPA and DHA content at the sn-2 position was detected. Remarkably, the optimized SAcyl obtained after 6 h, 82 bar, and 60 °C led to the highest EPA/DHA yield at the sn-2 position in the resulting molecule.

Shellfish industrial waste reuse

The global production of aquatic organisms has grown steadily in recent decades. This increase in production results in high volumes of by-products and waste, generally considered to be of low commercial value and part of them are consequently discarded in landfills or in the sea, causing serious environmental problems when not used. Currently, a large part of the reused aquaculture waste is destined for the feed industry. This generally undervalued waste presents an important source of bioactive compounds in its composition, such as: amino acids, carotenoids, chitin and its derivatives, fatty acids and minerals. These compounds are capable of offering numerous benefits due to their bioactive properties. However, the applicability of these compounds may be opportune in several other sectors. This review describes studies that seek to obtain and apply bioactive compounds from different sources of aquaculture waste, thus adding commercial value to these underutilized biomasses.HIGHLIGHTSVolume of aquaculture industrial waste from crustaceans and mollusks.Quantity and quality of bioactive components in aquaculture waste.Applications of recovered proteins, lipids, chitin, carotenoids and minerals.Future prospects for the destination of aquaculture waste.

Quantitative analysis of fatty acids and vitamin E and total lipid profiling of dietary supplements from the German market

Certain polyunsaturated fatty acids with n-3 double bonds are essential nutrients for the human body and are part of the bilayer of cell membranes or precursors of tissue hormones. The most abundant dietary n-3 fatty acids in human nutrition are α-linolenic, eicosapentaenoic, and docosahexaenoic acid and can be taken up through dietary sources such as vegetable oils or fish or, alternatively, dietary supplements with high levels of n-3 fatty acids. In previous studies, considerable variation of lipid patterns and quantities of n-3 fatty acids were observed. In this study, 33 dietary supplements from the German market, based on fish-, krill-, microalgae, and plant oil, have been analyzed. Lipid profiling (LC–MS) revealed triacylglycerols as the dominant lipid species in most samples. However, krill oil was rich in phospholipids and samples containing fatty acid concentrates featured abundant fatty acid ethyl esters and diacylglycerols. Furthermore, total lipid profiles showed considerable variance depending on the lipid sources (e.g., fish or plant oil), which was also apparent in fatty acid analysis. The contents of n-3 fatty acids ranged between 150 and 570 mg/g capsule content (GC–MS) and vitamin E (α-tocopherol and tocopheryl acetate) were found in quantities ranging from 1.2 to 86.1 mg/g capsule content (HPLC–UV/Vis). While our analyses indicated a good agreement between labeled and present quantities of total n-3 fatty acids and vitamin E for the majority of samples, significant differences in agreement between individual fatty acids were observed, as well as frequent mismatches between declared and present vitamin E derivatives.

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.

Integrated lipidomic and transcriptomic analyses reveal the mechanism of large yellow croaker roe phospholipids on lipid metabolism in normal-diet mice

Large yellow croaker roe phospholipids (LYCRPLs) could regulate the accumulation of triglycerides and blood lipid levels. However, there exists little research on the mechanism of LYCRPLs on lipid metabolism in normal-diet mice. In this work, the mice on a normal diet were given low-dose, medium-dose, and high-dose LYCRPLs by intragastric administration for 6 weeks. At the same time, the physiological and biochemical indicators of the mice were determined, and the histomorphological observation of the liver and epididymal fat was carried out. In addition, we examined the gene expression and lipid metabolites in the liver of mice using transcriptomic and lipidomic and performed a correlation analysis. The results showed that LYCRPLs regulated the lipid metabolism of normal-diet mice by affecting the expression of the glycerolipid metabolism pathway, insulin resistance pathway, and cholesterol metabolism pathway. This study not only elucidated the main pathway by which LYCRPLs regulate lipid metabolism, but also laid a foundation for exploring LYCRPLs as functional food supplements.

Obtention of Sacha Inchi (Plukenetia volubilis Linneo) Seed Oil Microcapsules as a Strategy for the Valorization of Amazonian Fruits: Physicochemical, Morphological, and Controlled Release Characterization

Sacha inchi seed oil (SIO) is a promising ingredient for the development of functional foods due to its large amount of high-value compounds; however, it is prone to oxidation. This work aimed to obtain SIO microcapsules using conventional and ultrasound probe homogenization and using spray- and freeze-drying technologies as effective approaches to improve the long-term stability of functional compounds. The application of ultrasound probe homogenization improved the rheological and emulsifying properties and decreased the droplet size and interfacial tension of emulsions. The microcapsules obtained by both drying technologies had low moisture (1.64-1.76) and water activity (0.03-0.11) values. Spray-dried microcapsules showed higher encapsulation efficiency (69.90-70.18%) compared to freeze-dried ones (60.02-60.16%). Thermogravimetric analysis indicated that heat protection was assured, enhancing the shelf-life. Results suggest that both drying technologies are considered effective tools to produce stable microcapsules. However, spray-drying technology is positioned as a more economical alternative to freeze-drying.

Determination of trace element and fatty acid levels in tissues of mirror and scaly carp (Cyprinus carpio L., 1758) living in Keban Dam Reservoir (Elazig)

This study investigated the concentrations of some accumulated trace metals (iron, manganese, zinc and copper) and fatty acids in liver and muscle tissues of mirror and scaly carp varieties (Cyprinus carpio L., 1758) living in Keban Dam Reservoir (Elazig), which is the second-largest artificial lake in Turkey that hosts commercially valuable and preferred fish varieties for human consumption. The inductively coupled plasma mass spectrometry (ICP-MS) method was used to analyse the concentrations of trace elements. Fatty acid levels were measured in a gas chromatography mass spectrometry (GC-MS) device, using a flame ionization detector (FID). Considering the two fish varieties and tissues that were studied, the mean metal concentrations (μg g^-1 ) were found in the following ranges: Fe 12.32-49.97, Mn 0.12-0.62, Zn 10.45-86.59 and Cu 2.74-11.86. Although the lowest levels were detected in the muscle tissue for all the metals examined, the levels in the liver tissue were significantly higher. According to the results of the analyses on fatty acid concentrations, the mean total saturated fatty acid levels in the muscle tissue of the scaly carp and mirror carp varieties were found to be 31.07 and 31.43 (%), respectively, whereas these values for the liver tissue were consecutively 22.36 and 22.08 (%). Successively, the mean total levels of unsaturated fatty acids were determined as 68.93 and 68.40 (%) in the muscle tissue and 77.64 and 77.92 in the liver tissue. This study, with the finding that the trace (metallic) element accumulation rates were below the upper limits of the tolerable range, and the examined fish varieties were rich in fatty acids, shows that mirror carp and scaly carp living in Keban Dam Reservoir are highly nutritious for human diets.

Advances in enzyme biocatalysis for the preparation of functional lipids

Functional lipids, mainly ω-3 polyunsaturated fatty acids (n-3 PUFAs) such as eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic (DHA; 22:6n-3), are known to have a variety of health benefits. Lipases and phospholipases are widely used to prepare different forms of structured lipids, since biocatalytic methods can be carried out under mild conditions, preserving the quality of the products. On the other hand, many processes still are conducted at high temperatures and with organic solvents, which are conditions unfavorable for the production of nutritional products. This article gives an updated overview of enzyme biocatalysis methods for the preparation of different derivatives containing n-3 PUFAs, including specific reactions, enzyme immobilization research for high-efficiency catalysis, and enzyme engineering technologies (higher selectivity, stability, and activity). Furthermore, advanced control strategies of biocatalytic processes and reactors are presented. The future prospect and opportunities for marine functional lipids are also discussed. Therefore, the obtainment of enzymes endowed with superior properties and the development of optimized processes, still have to be pursued to achieve greener bio-catalyzed processes.

Comparative Study of Bioactive Lipid Extraction from Squid (Doryteuthis gahi) by-Products by Green Solvents

A novel approach of bioactive lipid extraction by different green solvents was carried out on squid (Doryteuthis gahi) by-products. By-products (viscera, heads, skin, tails, etc.), considered as a single product, were subjected to the following solvent systems: ethanol, acetone, ethyl acetate, 1/1 ethanol/acetone, 1/1 ethanol/ethyl acetate, and 1/1 acetone/ethyl acetate. Analyses carried out included lipid yield, lipid class content, and fatty acid (FA) composition. Results were compared to the lipid extract obtained by the traditional procedure (1/1 chloroform/methanol). Lipid yields obtained by green solvents led to a 33.4−73.2% recovery compared to traditional extraction; the highest values (p < 0.05) were obtained by ethanol-containing systems. Compared to the traditional procedure, ethanol systems showed an 85.8−90.3% recovery of phospholipid compounds and no differences (p > 0.05) in the ω3/ω6 ratio. Green-extracting systems led to higher average values for eicosapentaenoic acid content (15.66−18.56 g·100 g−1 total FAs) and polyene index (1.93−3.29) than chloroform/methanol extraction; differences were significant (p < 0.05) for systems including acetone and ethyl acetate. No differences (p > 0.05) were detected for docosahexaenoic acid content between the traditional procedure and green systems, with all values being included in the 31.12−32.61 g·100 g−1 total FA range. The suitability of EtOH-containing green systems for extraction of bioactive lipid compounds from squid by-products was concluded.

Biochemical and morphological characterization of freshwater microalga Tetradesmus obliquus (Chlorophyta: Chlorophyceae)

Tetradesmus is a microalgal genus with biotechnological potential due to its rapid production of biomass, which is plenty in proteins, carbohydrates, lipids, and bioactives. However, its morphology and physiology need to be determined to guide better research to optimize the species cultivation and biocompounds processing. Thus, this study describes the biochemistry and morphology of the strain Tetradesmus obliquus BR003, isolated from a sample of freshwater reservoirs in a Brazilian municipality. In the T. obliquus BR003 dry biomass, we identified 61.6% unsaturated fatty acids, and 3.4% saturated fatty acids. Regarding other compounds, 28.50 ± 1.47 g soluble proteins/100 g, 0.14 ± 0.009 g carotenoids/100 g, 0.76 ± 0.013 g chlorophyll a/100 g, and 0.42 ± 0.015 g chlorophyll b/100 g with a chlorophyll a/b ratio of 1.8 were detected. The main chemical elements found were S, Mg, and P. The cells of BR003 were elliptically curved at the ends and without appendages. Histochemical tests showed carbohydrates distributed in the cytoplasm and pyrenoids, some lipid droplets, and proteins. The cytoplasm is rich in vacuoles, rough endoplasmic reticulum, mitochondria, and chloroplasts. The nucleus has a predominance of decondensed chromatin, and the cell wall has three layers. Chloroplasts have many starch granules and may be associated with a spherical central pyrenoid. To the best of our knowledge, this was the first biochemical description combined with ultrastructural morphological characterization of the strain T. obliquus BR003, grown under standard conditions, to demonstrate specific characteristics of the species.

The Potential of Phaeodactylum as a Natural Source of Antioxidants for Fish Oil Stabilization

Worldwide, fish oil is an important and rich source of the health-beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). It is, however, troubled by its high susceptibility towards lipid oxidation. This can be prevented by the addition of (preferably natural) antioxidants. The current research investigates the potential of Phaeodactylum carotenoids in this regard. The oxidative stability of fish oil and fish oil with Phaeodactylum addition is evaluated by analyzing both primary (PV) and secondary (volatiles) oxidation products in an accelerated storage experiment (37 °C). A first experimental set-up shows that the addition of 2.5% (w/w) Phaeodactylum biomass is not capable of inhibiting oxidation. Although carotenoids from the Phaeodactylum biomass are measured in the fish oil phase, their presence does not suffice. In a second, more elucidating experimental set-up, fish oil is mixed in different proportions with a Phaeodactylum total lipid extract, and oxidative stability is again evaluated. It was shown that the amount of carotenoids relative to the n-3 LC-PUFA content determined oxidative stability. Systems with a fucoxanthin/n-3 LC-PUFA ratio ≥ 0.101 shows extreme oxidative stability, while systems with a fucoxanthin/n-3 LC-PUFA ratio ≤ 0.0078 are extremely oxidatively unstable. This explains why the Phaeodactylum biomass addition did not induce oxidative stability.

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.

Fish oil encapsulated in soy protein particles by lyophilization. Effect of drying process

BACKGROUND

Fish oil is an important source of healthy ω-3 fatty acids to be used in functional foods. However, its autoxidation susceptibility, aroma and solubility make it difficult to use. Its encapsulation could reduce these disadvantages. This manuscript focuses on the drying stage of the encapsulation process. Its objective was to study the encapsulation of fish oil with soy proteins by emulsification and lyophilization and compare microparticles characteristics with those processed identically but spray dried.

RESULTS

Microparticles with different protein/oil ratios were prepared by emulsification and lyophilization. Soy proteins encapsulated fish oil in matrix-type microcapsules masking its typical odor and oily appearance. Microparticles dried by lyophilization showed a better solid recovery but lower encapsulation efficiency than those spray dried. Increasing protein/oil mass ratio of initial formulations seemed to favor initial lipid oxidation, but these differences were not appreciated when analyzing the oxidative stability over time (measured by Rancimat test). Porous structure and large surface area of lyophilized samples would favor oxygen easy penetration and exposition to free radicals, increasing lipid oxidation over time, while spray dried microparticles showed a good oxidative stability over time, like that of free oil.

CONCLUSION

Drying processes were determinants in the morphology of microcapsules, the efficiency of encapsulation and protection exerted on the oil. Although emulsifying and drying processes caused certain initial oil oxidation, soy proteins managed to mask fish oil flavors and spray dried systems showed a good perspective of oxidative stability of fish oil over time, better than that of lyophilized microparticles. © 2021 Society of Chemical Industry.

Optimisation of Healthy-Lipid Content and Oxidative Stability during Oil Extraction from Squid (Illex argentinus) Viscera by Green Processing

Green extraction was applied to Argentinean shortfin squid (Illex argentinus) viscera, consisting of a wet pressing method including a drying step, mechanic pressing, centrifugation of the resulting slurry, and oil collection. To maximise the oil yield and ω3 fatty acid content and to minimise the oil damage degree, a response surface methodology (RSM) design was developed focused on the drying temperature (45-85 °C) and time (30-90 min). In general, an increase of the drying time and temperature provided an increase in the lipid yield recovery from the viscera. The strongest drying conditions showed a higher recovery than 50% when compared with the traditional chemical method. The docosahexaenoic and eicosapentaenoic acid contents in the extracted oil revealed scarce dependence on drying conditions, showing valuable ranges (149.2-166.5 and 88.7-102.4 g·kg^-1 oil, respectively). Furthermore, the values of free fatty acids, peroxides, conjugated dienes, and ω3/ω6 ratio did not show extensive differences by comparing oils obtained from the different drying conditions. Contrary, a polyene index (PI) decrease was detected with increasing drying time and temperature. The RSM analysis indicated that optimised drying time (41.3 min) and temperature (85 °C) conditions would lead to 74.73 g·kg^-1 (oil yield), 1.87 (PI), and 6.72 (peroxide value) scores, with a 0.67 desirability value.