Search Results (31)

Purpose: To investigate associations between lipid oxidation biomarkers (oxylipins), antioxidant micronutrients, lipoprotein particles, and apolipoproteins in multiple sclerosis (MS). Methods: Blood and neurological assessments were collected from 30 healthy controls, 68 relapsing remitting MS subjects, and 37 progressive MS subjects. Hydroxy (H) and hydroperoxy lipid peroxidation products of the polyunsaturated fatty acids (PUFAs) arachidonic (20:4, ω-6), linoleic (octadecadienoic acid or ODE, 18:2, ω-6), eicosapentaenoic (20:5, ω-3), and α-linolenic (18:3, ω-3) acids were measured using liquid chromatography–mass spectrometry. Antioxidant micronutrients, including β-cryptoxanthin and lutein/zeaxanthin, were quantified by high-performance liquid chromatography. Lipoprotein and metabolite profiles were obtained using nuclear magnetic resonance spectroscopy. Regression models were adjusted for age, sex, body mass index, and disease status. Results: The 9-hydroxy octadecadienoic acid to 13-hydroxy octadecadienoic acid ratio (9-HODE/13-HODE ratio), which reflects autoxidative versus enzymatic oxidation, was associated with MS status (p = 0.002) and disability on the Expanded Disability Status Scale (p = 0.004). Lutein/zeaxanthin (p = 0.023) and β-cryptoxanthin (p = 0.028) were negatively associated with the 9-HODE/13-HODE ratio. Apolipoprotein-CII, a marker of liver-X-receptor (LXR) signaling, was associated with 9-HODE/13-HODE ratio and other oxylipins. Octadecadienoic fatty acid-derived oxylipins were negatively associated with LC3A, a mitophagy marker, and positively correlated with 7-ketocholesterol, a cholesterol autoxidation product. Conclusions: Autoxidation of PUFAs is associated with greater disability in MS. Higher β-cryptoxanthin and lutein/zeaxanthin were associated with reduced auto-oxidation. Lipid peroxidation shows associations with LXR signaling, mitophagy, inflammation, and cholesterol autoxidation. Full article

Essential oils (EOs) are complex volatile mixtures that exhibit antioxidant activity through both chemical and biological pathways. Phenolic constituents act as efficient chain-breaking radical-trapping antioxidants, whereas some non-phenolic terpenes operate through distinct mechanisms. Notably, γ-terpinene functions via a “radical export” pathway, generating hydroperoxyl radicals that intercept lipid peroxyl radicals and accelerate chain termination. Recent methodological advances, such as inhibited autoxidation kinetics, oxygen-consumption assays, and fluorescence-based lipid peroxidation probes, have enabled more quantitative evaluation of these activities. Beyond direct radical chemistry, EOs also regulate redox homeostasis by modulating signaling networks such as Nrf2/Keap1, thereby activating antioxidant response element–driven enzymatic defenses in cell and animal models. Phenolic constituents and electrophilic compounds bearing an α,β-unsaturated carbonyl structure may directly activate Nrf2 by modifying Keap1 cysteine residues, whereas non-phenolic terpenes likely depend on oxidative metabolism to form active electrophilic species. Despite broad evidence of antioxidant efficacy, molecular characterization of EO–protein interactions remains limited. This review integrates radical-chain dynamics with redox signaling biology to clarify the mechanistic basis of EO antioxidant activity and to provide a framework for future research. Full article

Moringa oleifera tree is recognised for its high content of bioactive compounds. This work explored the potential of incorporating its leaves or respective extracts into white chocolate to enhance its biological and sensory properties as white chocolate lacks the beneficial compounds found in cocoa. In this study, a phenolic-rich extract was obtained from Moringa oleifera leaf powder, and its biological properties and phenolic composition were characterised. The extract displayed good antioxidant capacity, especially against ABTS radical (IC₅₀ = 162.0 mg/L). Additionally, it exhibited strong inhibitory potential against α-amylase and β-glucosidase, achieving average inhibition rates of 79.9% and 98.0%, respectively. The main phenolic compounds identified included catechin (0.211 mg_compound/g_extract), caffeic acid (0.056 mg_compound/g_extract), and quercetin (0.031 mg_compound/g_extract). White chocolate samples were fortified with 1% and 3% M. oleifera leaf extract, resulting in increased antioxidant properties and oxidative stability. All formulations were microbiologically safe, and the sample containing 3% extract showed the highest DPPH inhibition after 15 days of storage and a higher delay in the autoxidation of lipids over time. The fortification of white chocolate with M. oleifera leaf extract has the potential to transform it into a functional product rich in antioxidants, providing health benefits and increased value. Full article

Consumers include pumpkin seeds in their diet as a snack in raw form or minimally processed by roasting. This process enables the seeds to develop a characteristic aroma and color. Herbs and spices are also distinguished by a pleasant and delicate aroma. Among them, marjoram is particularly suited to drying, retaining its flavor better than other dried herbs. Marjoram can be used to impart flavor and aroma to food products and extend their shelf life because it can prevent lipid autoxidation. In this study, pumpkin seeds (Cucurbita pepo) were roasted with and without dried marjoram at 110 and 160 °C for 10 and 30 min, after which the oils were extracted. The results showed that with increasing temperature and roasting time, the moisture content and water activity of pumpkin seeds decreased. Furthermore, roasting pumpkin seeds with marjoram, particularly at 110 °C, enriched their aroma profile with terpenes characteristic of the marjoram aroma. Whether pumpkin seeds were roasted with or without marjoram, the fatty acid composition of the oils obtained was dominated by palmitic, stearic, oleic, and linoleic acids. However, the presence of marjoram during pumpkin seeds roasting resulted in lower peroxide values and specific extinction coefficients K₂₃₂ and K₂₇₀ in the oils obtained compared to their counterparts roasted without this spice. In addition, all the oils showed the ability to scavenge DPPH^· radicals and were characterized by a higher proportion of yellow (positive value of the b* parameter) and green (negative value of the a* parameter) color. In comparison with the oil extracted from unroasted pumpkin seeds, the oil obtained after roasting exhibited a lower chlorophyll and a higher carotenoid content. Thus, roasting pumpkin seeds with spices may enrich their aroma profile with additional components, and the oils obtained may be characterized by better quality parameters. Full article

Virgin olive oil (VOO) is a globally esteemed product renowned for its chemical composition, nutritional value, and health benefits. Consumers seeking natural, nutritious, and healthy foods increasingly favor VOO. The optimization of the extraction system ensures the production of high-quality VOO with abundant antioxidant compounds that naturally protect it from degradation. Proper storage is crucial in maintaining the quality of VOO, prompting the exploration of novel extraction and preservation techniques. Factors such as light, temperature, and oxygen greatly influence the degradation process, resulting in reduced levels of natural antioxidants like polyphenols. Undesirable by-products and non-aromatic compounds may be formed, making the oil unacceptable over time. On the basis of all this consideration, this study aimed to evaluate the synergic use of two different gases (CO₂ and argon) during the malaxation phase to limit radical development and delay lipid autoxidation. Additionally, unconventional preservation systems, namely argon headspace, shellac, and bottle in bag, were assessed over a period of 150 days. The results evidenced that the use of CO₂ and argon during the malaxation process resulted in an improvement in the oil quality compared to the one obtained with the traditional system. However, in traditional oils, the alternative packaging systems determined interesting outcomes as they were able to positively affect different parameters, while the packaging effect was more mitigated in the test oils. Full article

Nitroxides, stable synthetic free radicals, are promising antioxidants, showing many beneficial effects both at the cellular level and in animal studies. However, the cells are usually treated with high millimolar concentrations of nitroxides which are not relevant to the concentrations that could be attained in vivo. This paper aimed to examine the effects of low (≤10 μM) concentrations of three nitroxides, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO), 4-hydroxy-TEMPO (TEMPOL) and 4-amino-TEMPO (TEMPAMINE), in pure chemical systems and on SH-SY5Y cells transfected with the human tau protein (TAU cells), a model of chronic cellular oxidative stress, and transfected with the empty plasmid (EP cells). All nitroxides were active in antioxidant-activity tests except for the 2,2′-azinobis-(3-ethylbenzthiazolin-6-sulfonate) radical (ABTS^•) decolorization assay and reduced Fe³⁺, inhibited autoxidation of adrenalin and pyrogallol and oxidation of dihydrorhodamine123 by 3-morpholino-sydnonimine SIN-1. TEMPO protected against fluorescein bleaching from hypochlorite, but TEMPAMINE enhanced the bleaching. Nitroxides showed no cytotoxicity and were reduced by the cells to non-paramagnetic derivatives. They decreased the level of reactive oxygen species, depleted glutathione, and increased mitochondrial-membrane potential in both types of cells, and increased lipid peroxidation in TAU cells. These results demonstrate that even at low micromolar concentrations nitroxides can affect the cellular redox equilibrium and other biochemical parameters. Full article

Plant-based milk alternatives are a fast-growing segment of food industry resulting in the generation of large amounts of by-products, often containing comparable and even higher amounts of valuable phytochemicals than the target products. Common buckwheat (Fagopyrum esculentum M.) Panda variety has been selected for this study, which aims to compare the antioxidant potential of beverages produced from buckwheat whole and dehulled grains, as well as cakes obtained as residues. After combining, evaporating and freeze-drying, extracts were subjected to RP-HPLC-DAD, total phenolics and in vitro antiradical and antioxidant assays (FRAP, ABTS, DPPH and lipid autoxidation). Flavonoids (3.09 mg/100 mL) exceeded the content of phenolic acids (2.35 mg/100 mL) in the beverages prepared from dehulled grains, but their content (1.69 mg/100 mL) in the beverages from whole grains was lower than that of phenolic acids (2.93 mg/100 mL). The antiradical capacity of beverages did not differ significantly, regardless of the method used. In case of by-products, a higher ferric-reducing capacity and scavenging activity towards DPPH^• of cakes from whole grains compared to that from dehulled grains was established. The activity of cake extracts under lipid autoxidation conditions increased with the increase in their concentrations from 0.12 wt% to 0.16 wt% in the oxidizable substrate. Full article

In this study, lipoxygenase (LOX) extracted from dry-cured mackerel was purified, resulting in a 4.1-fold purification factor with a specific activity of 493.60 U/min·g. LOX enzymatic properties were assessed, referring to its optimal storage time (1–2 days), temperature (30 °C), and pH value (7.0). The autoxidation and LOX-induced oxidation of palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:2n9c), linoleic acid (C18:2n6c), arachidonic acid (C20:4), EPA (C20:5), and DHA (C22:6n3) were simulated to explore the main metabolic pathways of key flavors in dry-cured mackerel. The results showed that the highest LOX activity was observed when arachidonic acid was used as a substrate. Aldehydes obtained from LOX-treated C18:1n9c and C18:2n6c oxidation, which are important precursors of flavors, were the most abundant. The key flavors in dry-cured mackerel were found in the oxidative products of C16:0, C18:0, C18:1n9c, C18:2n6c, and C20:4. Heptanaldehyde could be produced from autoxidation or LOX-induced oxidation of C18:0 and C18:1n9c, while nonal could be produced from C18:1n9c and C18:2n6c oxidation. Metabolic pathway analysis revealed that C18:1n9c, C18:2n6c, EPA, and DHA made great contributions to the overall flavor of dry-cured mackerel. This study may provide a relevant theoretical basis for the scientific control of the overall taste and flavor of dry-cured mackerel and further standardize its production. Full article

Peroxiredoxin 2 (Prdx2) is the third most abundant erythrocyte protein. It was known previously as calpromotin since its binding to the membrane stimulates the calcium-dependent potassium channel. Prdx2 is present mostly in cytosol in the form of non-covalent dimers but may associate into doughnut-like decamers and other oligomers. Prdx2 reacts rapidly with hydrogen peroxide (k > 10⁷ M⁻¹ s⁻¹). It is the main erythrocyte antioxidant that removes hydrogen peroxide formed endogenously by hemoglobin autoxidation. Prdx2 also reduces other peroxides including lipid, urate, amino acid, and protein hydroperoxides and peroxynitrite. Oxidized Prdx2 can be reduced at the expense of thioredoxin but also of other thiols, especially glutathione. Further reactions of Prdx2 with oxidants lead to hyperoxidation (formation of sulfinyl or sulfonyl derivatives of the peroxidative cysteine). The sulfinyl derivative can be reduced by sulfiredoxin. Circadian oscillations in the level of hyperoxidation of erythrocyte Prdx2 were reported. The protein can be subject to post-translational modifications; some of them, such as phosphorylation, nitration, and acetylation, increase its activity. Prdx2 can also act as a chaperone for hemoglobin and erythrocyte membrane proteins, especially during the maturation of erythrocyte precursors. The extent of Prdx2 oxidation is increased in various diseases and can be an index of oxidative stress. Full article

Cottonseed is a natural product of cotton (Gossypium spp.) crops. This work evaluated the oxidative stability of cottonseed butters through accelerated autoxidation by storage at 60 °C for 25 days. Three oxidative stability parameter values (peroxide value, p-anisidine value, and total oxidation value) were monitored over the storage time. These chemical measurements revealed that the storage stability of the butter products was dominated by primary oxidation of lipid (oil) components, while the secondary oxidation levels were relatively unchanged over the storage time. An analysis of the tocopherols (natural oxidants in cottonseed) suggested not only the protection function of the molecules against oxidation of the cottonseed butter during storage, but also the dynamic mechanism against the primary oxidation of lipid components. Attenuated total reflectance–Fourier-transform infrared spectroscopy (ATR–FTIR) data confirmed no changes in the major C functional groups of cottonseed butters over the storage time. On the other hand, characteristic minor peaks of conjugated dienes and trienes related to lipid oxidation were impacted by the accelerated storage. As each day of accelerated oxidation at 60 °C is equivalent to 16 days of storage at 20 °C, observations in this work should have reflected the oxidative stability behaviors of the cottonseed butters after about 13 months of shelf storage under ambient storage conditions. Thus, these data that were collected under the accelerated oxidation testing would be useful not only to create a better understanding of the autooxidation mechanism of lipid molecules in cottonseed butters, but also in developing or recommending appropriate storage conditions for cottonseed end products to prevent them from quality degradation. Full article

Lipids and their oxidation products were quantified in loess samples from the Negev Desert (Israel), well known to be a source of desert dusts in the eastern Mediterranean Basin. The results obtained showed the presence of higher plant material (angiosperms and gymnosperms), but also bacteria and fungi. Although a strong autoxidation of lipids could be demonstrated, the resulting oxidation products appeared to be weakly accumulated, likely due to the high temperatures and solar irradiance observed in the Negev Desert. Incubation of this dust analogue in fresh water (to mimic their behavior in rainwater) resulted in the release of metal ions (mainly iron), but also a fast heterolytic degradation of their weak content of hydroperoxides. Induction of autoxidation processes in dry and wet atmospheric dusts arising from the Negev Desert in seawater (needing simultaneous presence of metal ions and hydroperoxides) seems thus very unlikely due to the relatively high pH of seawater hindering metal dissolution and the degradation of hydroperoxides in rainwater. Full article

Edible nuts and dried fruits, usually traded together in the global market, are one of the cornerstones of the Mediterranean diet representing a source of essential nutrients and bioactives. The food industry has an interest in the selection of high-quality materials for new product development while also matching consumers’ expectations in terms of sensory quality. In this study, walnuts (Juglans regia), almonds (Prunus dulcis), and dried pineapples (Ananas comosus) are selected as food models to develop an integrated analytical strategy for the informative volatile organic compounds (VOCs) quali- and quantitative profiling. The study deals with VOCs monitoring over time (12 months) and in the function of storage conditions (temperature and atmosphere).VOCs are targeted within those: (i) with a role in the product’s aroma blueprint (i.e., key-aromas and potent odorants); (ii) responsible for sensory degradation (i.e., rancidity); and/or (iii) formed by lipid autoxidation process. By accurate quantitative determination of volatile lipid oxidation markers (i.e., hexanal, heptanal, octanal, nonanal, decanal, (E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal) product quality benchmarking is achieved. The combination of detailed VOCs profiling by headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) and accurate quantification of rancidity markers by multiple headspace-SPME (MHS-SPME) answers many different questions about shelf-life (i.e., aroma, storage stability, impact of temperature and storage atmosphere, rancidity level), while providing reliable and robust data for long-range studies and quality controls. The quantification associated with HS-SPME profiling is demonstrated and critically commented on to help the industrial research in a better understanding of the most suitable analytical strategies for supporting primary materials selection and new product development. Full article

Commercially available oxygen scavengers used to prevent lipid autoxidation, microbial growth and enzymatic browning in food products present several issues, which include the usage of metals and their moisture dependence to work properly. We present the synthesis and characterization of a moisture-independent oil-based oxygen scavenging system comprised of linseed oil and silica nanoparticles. The system was synthesized via sol-gel chemistry and was characterized using morphological analysis (SEM, AFM, TEM, and N₂ adsorption/desorption), oil-loading analysis (TGA), and surface analysis (ζ-potential and ATR-FTIR). Performance of the system was evaluated through headspace measurements and reproducibility of synthetic procedure was verified using six replicates. Nanoparticles showed the desired spherical shape with a diameter of (122.7 ± 42.7 nm) and mesoporosity (pore diameter = 3.66 ± 0.08 nm), with an encapsulation efficiency of 33.9 ± 1.5% and a highly negative ζ-potential (−56.1 ± 1.2 mV) in basic solution. Performance of the system showed a promising high value for oxygen absorption of 25.8 ± 4.5 mL O₂/g of encapsulated oil (8.3 ± 1.5 mL O₂/g of nanocapsules) through a moisture independent mechanism, which suggests that the synthesized system can be used as an oxygen scavenger in dry atmosphere conditions. Full article

Undesirable flavor formation in fish is a dynamic biological process, decreasing the overall flavor quality of fish products and impeding the sale of fresh fish. This review extensively summarizes chemical compounds contributing to undesirable flavors and their sources or formation. Specifically, hexanal, heptanal, nonanal, 1−octen−3−ol, 1−penten−3−ol, (E,E)−2,4−heptadienal, (E,E)−2,4−decadienal, trimethylamine, dimethyl sulfide, 2−methyl−butanol, etc., are characteristic compounds causing off−odors. These volatile compounds are mainly generated via enzymatic reactions, lipid autoxidation, environmentally derived reactions, and microbial actions. A brief description of progress in existing deodorization methods for controlling undesirable flavors in fish, e.g., proper fermenting, defatting, appropriate use of food additives, and packaging, is also presented. Lastly, we propose a developmental method regarding the multifunctional natural active substances made available during fish processing or packaging, which hold great potential in controlling undesirable flavors in fish due to their safety and efficiency in deodorization. Full article

Lipids in food are a source of essential fatty acids and also play a crucial role in flavor and off-flavor development. Lipids contribute to food flavor generation due to their degradation to volatile compounds during food processing, heating/cooking, and storage and/or interactions with other constituents developed from the Maillard reaction and Strecker degradation, among others. The degradation of lipids mainly occurs via autoxidation, photooxidation, and enzymatic oxidation, which produce a myriad of volatile compounds. The oxidation of unsaturated fatty acids generates hydroperoxides that then further break down to odor-active volatile secondary lipid oxidation products including aldehydes, alcohols, and ketones. In this contribution, a summary of the most relevant and recent findings on the production of volatile compounds from lipid degradation and Maillard reactions and their interaction has been compiled and discussed. In particular, the effects of processing such as cooking, drying, and fermentation as well as the storage of lipid-based foods on flavor generation are briefly discussed. Full article