Comprehensive Analysis of Fatty Acid and Oxylipin Patterns in n3-PUFA Supplements

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.

Impact of Nonthermal Plasma Treatment on the Oxidation of Lipids with Different Unsaturation Degrees

Nonthermal plasma (NTP) treatment of food presents a new technology for the industry but raises concerns about lipid oxidation due to the presence of reactive species. Considering the critical role of the degree of unsaturation in lipid oxidation, this study investigates NTP-induced oxidation across various unsaturated lipids. These lipids are six oil samples primarily containing one of the following methylesters: oleate, linoleate, linolenate, arachidonate, eicosapentaenoate, and docosahexaenoate. Samples were treated with a nonthermal surface dielectric barrier discharge. Plasma-induced effects were first examined by classical lipid oxidation indicators, such as the peroxide value and p-anisidine value. The specific volatile oxidation products, including hexanal, nonanal, trans-2-hexenal, and methyl 9-oxononanoate, were determined to further elucidate the impact of ozone-related oxidation. Monitoring the production of selected nonvolatile oxidation products, such as epoxy-, oxo-, and hydroxy fatty acid methylesters, confirmed that plasma treatment facilitated the decomposition of lipid hydroperoxide. Generally, the level of plasma-induced oxidation increased in parallel with the unsaturation degree of the studied samples, except for the quantity of individual volatile carbonyls. The long-term effect of NTP treatment was investigated by a stability test, revealing that the oxidative stability depended on the input gas of plasma treatment, the sensitivity of the treated sample, and the presence of antioxidants. Except for the focus on the NTP impact, this study offered a case study of a comprehensive investigation into lipid oxidation.

Exploring oxylipins in processed foods: Understanding mechanisms, analytical perspectives, and enhancing quality with lipidomics

Oxylipins are active lipid compounds formed through the oxidation of unsaturated fatty acids. These compounds have drawn considerable attention due to the potential impact on human health and processed food quality. Therefore, this study aimed to deepen current understanding and assess recent analytical advancements regarding the physiological roles of oxylipins in processed food products using lipidomics. The mechanisms behind oxylipins production in processed foods were extensively investigated, underscoring potential associations with chronic diseases. This indicates the need for innovative strategies to mitigate harmful oxylipins levels to enhance the safety and shelf life of processed food products. The results showed that mitigation methods, including the use of antioxidants and optimization of processing parameters, reduced oxylipins levels. The integration of lipidomics with food safety and quality control processes is evident in cutting-edge methods such as nuclear magnetic resonance and mass spectrometry for compliance and real-time evaluation. Aside from envisioning the future trajectory of food science and industry through prospective studies on oxylipins and processed foods, the results also provide the basis for future investigations, innovation, and advancements in the dynamic field of food science and technology.

Microalgae as a New Source of Oxylipins: A Comprehensive LC-MS-Based Analysis Using Conventional and Green Extraction Methods

Microalgae are promising sources of essential lipids, including omega-3 and omega-6 polyunsaturated fatty acids (n-3 and n-6 PUFA) and novel lipid metabolites like oxylipins. However, limited data exist on the oxylipin profile, its characterization, and the potential impact of the extraction process on these metabolites in microalgae. Thus, our study aimed to investigate the fatty acid and oxylipin profile of four microalgal species of interest (Microchloropsis gaditana, Tisochrysis lutea, Phaeodactylum tricornutum, and Porphyridium cruentum) while also examining the impact of the extraction method, with a focus on developing a greener process using ultrasound-assisted extraction (UAE) and ethanol. The UAE method showed similar oxylipin profiles, generally yielding concentrations comparable to those of the conventional Folch method. In total, 68 oxylipins derived from n-3 and n-6 PUFA were detected, with the highest concentrations of n-3 oxylipins found in P. tricornutum and T. lutea and of n-6 oxylipins in P. cruentum. This study provides the most extensive oxylipin characterization of these microalgae species to date, offering insights into alternative extraction methods and opening new avenues for further investigation of the significance of oxylipins in microalgae.

Efficient Expression and Application of a Modified Rhizomucor miehei Lipase for Simultaneous Production of Biodiesel and Eicosapentaenoic Acid Ethyl Ester from Nannochloropsis Oil

Few reports exist on one-step enzymatic methods for the simultaneous production of biodiesel and eicosapentaenoic acid ethyl ester (EPA-EE), a high-value pharmaceutical compound. This study aimed to efficiently express Rhizomucor miehei lipase (pRML) in Pichia pastoris X-33 via propeptide mutation and high-copy strain screening. The mutated enzyme was then used to simultaneously catalyze the production of both biodiesel and EPA-EE. The P46N mutation in the propeptide (P46N-pRML) significantly boosted its production, with the four-copy strain increasing enzyme yield by 3.7-fold, reaching 3425 U/mL. Meanwhile, its optimal temperature increased to 45-50 °C, pH expanded to 7.0-8.0, specific activity doubled, Km reduced to one-third, and kcat/Km increased 7-fold. Notably, P46N-pRML efficiently converts Nannochloropsis gaditana oil's eicosapentaenoic acid (EPA). Under optimal conditions, it achieves up to 93% biodiesel and 92% EPA-EE yields in 9 h. Our study introduces a novel, efficient one-step green method to produce both biodiesel and EPA-EE using this advanced enzyme.

Do meals contain a relevant amount of oxylipins? LC-MS-based analysis of oxidized fatty acids in food

Several oxylipins are potent lipid mediators and are discussed to be absorbed after oral intake. However, information about their concentrations in oils and processed foods are scarce. Here, we analyzed the concentrations of mono-, di- and multihydroxy- as well as epoxy-PUFA in virgin and refined oils as well as in different foods/meals. Oil refining causes hydrolysis of epoxy-PUFA and thus high dihydroxy-PUFA concentrations (e.g. 15,16-DiHODE 290 µg/g in refined vs. 15 µg/g in virgin rapeseed oil), making the epoxy-to-diol ratio a potential marker for refined oils. Low oxylipin levels were found in foods with high amounts of saturated fatty acids such as Hamburger patties (around 30 µg/g). High concentrations (up to 1200 µg/g, 80 mg per serving) and high oxylipin/precursor-PUFA ratios were found in fried falafel and processed foods such as vegetarian sausage/fish fingers. Our study provides first insights in the oxylipin concentrations of our daily food, indicating a relevant intake.

Adipocyte autophagy limits gut inflammation by controlling oxylipin and IL-10

Lipids play a major role in inflammatory diseases by altering inflammatory cell functions, either through their function as energy substrates or as lipid mediators such as oxylipins. Autophagy, a lysosomal degradation pathway that limits inflammation, is known to impact on lipid availability, however, whether this controls inflammation remains unexplored. We found that upon intestinal inflammation visceral adipocytes upregulate autophagy and that adipocyte-specific loss of the autophagy gene Atg7 exacerbates inflammation. While autophagy decreased lipolytic release of free fatty acids, loss of the major lipolytic enzyme Pnpla2/Atgl in adipocytes did not alter intestinal inflammation, ruling out free fatty acids as anti-inflammatory energy substrates. Instead, Atg7-deficient adipose tissues exhibited an oxylipin imbalance, driven through an NRF2-mediated upregulation of Ephx1. This shift reduced secretion of IL-10 from adipose tissues, which was dependent on the cytochrome P450-EPHX pathway, and lowered circulating levels of IL-10 to exacerbate intestinal inflammation. These results suggest an underappreciated fat-gut crosstalk through an autophagy-dependent regulation of anti-inflammatory oxylipins via the cytochrome P450-EPHX pathway, indicating a protective effect of adipose tissues for distant inflammation.

Factors affecting variability in free oxylipins in mammalian tissues

PURPOSE OF THE REVIEW

Along with the growing interest in oxylipins is an increasing awareness of multiple sources of variability in oxylipin data. This review summarizes recent findings that highlight the experimental and biological sources of variation in free oxylipins.

RECENT FINDINGS

Experimental factors that affect oxylipin variability include different methods of euthanasia, postmortem changes, cell culture reagents, tissue processing conditions and timing, storage losses, freeze-thaw cycles, sample preparation techniques, ion suppression, matrix effects, use and availability of oxylipin standards, and postanalysis procedures. Biological factors include dietary lipids, fasting, supplemental selenium, vitamin A deficiency, dietary antioxidants and the microbiome. Overt, but also more subtle differences in health affect oxylipin levels, including during resolution of inflammation and long-term recovery from disease. Sex, genetic variation, exposure to air pollution and chemicals found in food packaging and household and personal care products, as well as many pharmaceuticals used to treat health conditions also affect oxylipin levels.

SUMMARY

Experimental sources of oxylipin variability can be minimized with proper analytical procedures and protocol standardization. Fully characterizing study parameters will help delineate biological factors of variability, which are rich sources of information that can be used to probe oxylipin mechanisms of action and to investigate their roles in health.

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.

Encapsulated Microstructures of Beneficial Functional Lipids and Their Applications in Foods and Biomedicines

Beneficial functional lipids are essential nutrients for the growth and development of humans and animals, which nevertheless possess poor chemical stability because of heat/light-sensitivity. Various encapsulation technologies have been developed to protect these nutrients against adverse factors. Different microstructures are exhibited through different encapsulation methods, which influence the encapsulation efficiency and release behavior at the same time. This review summarizes the effects of preparation methods and process parameters on the microstructures of capsules at first. The mechanisms of the different microstructures on encapsulation efficiency and controlled release behavior of core materials are analyzed. Next, a comprehensive overview on the beneficial functional lipids capsules in the latest food and biomedicine applications are provided as well as the matching relationship between the microstructures of the capsules and applications are discussed. Finally, the remaining challenges and future possible directions that have potential interest are outlined. The purpose of this review is to convey the construction of beneficial functional lipids capsules and the function mechanism, a critical analysis on its current status and challenges, and opinions on its future development. This review is believed to promote communication among the food, pharmacy, agronomy, engineering, and nutrition industries.