Investigation of Lipid Oxidation in High- and Low-Lipid-Containing Topical Skin Formulations

Lipid oxidation can impact the odour of skin care products during storage. A study was conducted to identify and monitor representative markers for lipid oxidation in skin care products over time. Four lip care formulations and three skin care formulations with different lipid contents were stored at various cosmetic industry‐relevant conditions for 84 days. The skin care products were analysed for lipid hydroperoxides and secondary volatile oxidation products. A trained sensory panel performed an odour difference (triangle) test and odour‐profiled the products to detect and describe odour changes during storage. Several potential markers for lipid oxidation were identified. In skin care formulations, peroxide value (PV) analysis was a useful marker for lipid oxidation if the product was exposed to light during storage, but no clear changes were observed for PV in samples stored under other conditions. Furthermore, concentrations of several secondary volatile oxidation products increased during storage, and the highest increase was observed for products exposed to light. Pentanal and heptanal were found to be reliable markers for secondary volatile oxidation products in the skin care formulations (especially during exposure to light), whereas in the lip care formulations the best candidates were pentanal (especially during exposure to light and iron), 2‐methyl furan and 3‐methyl‐3‐buten‐2‐one (especially during exposure to light, iron and high temperatures).     

Cholesterol oxides content in selected animal products determined by GC‐MS

The aim of this study was to evaluate the effect of heat treatment of selected animal products on formation of cholesterol oxidation products (COP) and also to determine their content in selected pates and fermented pork sausage which are available on the Polish market. COP content in pates was significantly lower as compared to fermented sausages, and ranged from 39.5 to 43.1 µg/100 g; COP in sausages ranged from 195.8 to 263.4 µg/100 g of product. COP content in pan fried meats, chops, and fish fillets varied from 6.2 to 991.2 µg/100 g products. This paper demonstrates the method for determining the content of COP by the use of selected ion technique with the aid of MS. Practical applications: The method described is useful for the investigation of oxysterols in food matrices. The method is used for the investigation of the presence and content of COP, such as: 7β‐hydroxycholesterol, 5α,6α‐epoxycholesterol, 5β,6β‐epoxycholesterol, 5α‐cholestane‐3β,5β,6β‐triol, 7‐ketocholesterol, and 25‐hydroxycholesterol. The obtained data about COP content in selected animal products and their formation during heat treatment are crucial for creating a reliable database to assess their daily intakes and biological effects in humans.     

Lipid Profiles in By‐Products and Muscles of Three Shrimp Species (Penaeus monodon,Penaeus vannamei,and Penaeus chinensis)

To better understand the health benefits of lipids in shrimp and evaluate their potential value, a comprehensive analysis of lipid profiles in by‐products (head and body carapace) and muscles of shrimps Penaeus monodon, Penaeus vannamei, and Penaeus chinensis is performed. Results show that freeze‐dried muscles of these shrimps contain 3.83%, 4.39%, and 2.93% of lipids, respectively, while the corresponding by‐products contain 4.69%, 5.89%, and 5.39% of lipids, respectively. The total lipids comprise glycerophospholipid (PL, 54.86–77.29%), cholesterol (12.67–18.79%), triacylglycerol (1.28–7.02%), diacylglycerol (0.27–1.58%), monoacylglycerol (0.32–3.04%), and free fatty acid (FFA, 2.84–20.58%). Further, PL contains cholineglycerophospholipid (PLCho, 49.75–66.99 mol%), ethanolamineglycerophospholipid (PLEtn, 14.02–28.16 mol%), serineglycerophospholipid (PLSer, 4.85–12.66 mol%), inositolglycerophospholipid (PLIns, 4.36–15.63 mol%), and cholinelysoglycerophospholipid (LPLCho, 2.07–6.35 mol%). Lipids are abundant in polyunsaturated FA (36.55–42.72% of total FA), among which eicosapentaenoic acid (6.38–11.59% of total FA), and docosahexaenoic acid (7.63–12.08% of total FA) are dominant. About 200 species of PL belonging to PLCho, PLEtn, PLIns, LPLCho, lysoglycerophosphoethanolamine (LPLEtn), and lysoglycerophosphoserine (LPLSer) are characterized. Moreover, the by‐products contain higher amounts of astaxanthin than the muscles. Considering high level of PUFA enriched PL, shrimp by‐products can serve as a source for nutritional lipids. Practical Applications: This study presented a comprehensive analysis of the lipid profiles in by‐products (head and body carapace) and muscles of shrimps Penaeus monodon, Penaeus vannamei, and Penaeus chinensis. The results obtained justified the use of by‐products in shrimp processing, indicating that by‐products can be used for commercial exploitation and production of value‐added products due to PUFA‐enriched PL, especially EPA and DHA.     

Advanced Oxidation Processes in Pharmaceutical Formulations: Photo-Fenton Degradation of Peptides and Proteins

Formulations of therapeutic proteins are sensitive to photo-degradation by near UV and visible light. Mechanistically, especially the processes leading to protein modification under visible light exposure are not understood. Potentially, these processes may be triggered by a ligand to metal charge transfer in excipient-metal complexes. This article summarizes recent analytical and mechanistic work on such reactions under experimental conditions relevant to pharmaceutical formulations.     

Characteristic Oxidation Products of Choline Plasmalogens are Detectable in Cattle and Roe Deer Spermatozoa by MALDI-TOF Mass Spectrometry

Plasmalogens (1-O-alk-1′-enyl-2-acyl-sn-glycero-3-phosphocholines and -phosphoethanolamines) are important constituents of spermatozoa membranes and possess significant antioxidative properties. This particularly holds as plasmalogens from spermatozoa also possess a very high content of highly unsaturated fatty acyl residues (especially 22:6). The organic spermatozoa extracts of two different ruminants (cattle and roe deer) were analyzed for their contents of characteristic choline plasmalogen oxidation products by matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry. It will be shown that 1-hydroxy-2-docosahexaenoyl-sn-glycero-3-phosphocholine (LPC 22:6) and formyl-LPC 22:6 are reliable measures of lipid oxidation of spermatozoa and allow, accordingly, conclusions about the storage conditions. All data on spermatozoa were also confirmed by the investigation of the oxidation behavior of selected reference compounds. It will be shown that, equally if plasmalogens or diacyl PC species are used, oxidation takes place primarily at the double bond next to the glycerol backbone. These data were additionally confirmed by recording the corresponding post source decay (PSD) fragment ion spectra.     

Black Raspberry Seed Oil Improves Lipid Metabolism by Inhibiting Lipogenesis and Promoting Fatty‐Acid Oxidation in High‐Fat Diet‐Induced Obese Mice and db/db Mice

The objective of this study was to evaluate the beneficial effect of α‐linolenic acid‐rich black raspberry seed (BRS) oil on lipid metabolism in high‐fat diet (HFD)‐induced obese and db/db mice. Five‐week‐old C57BL/6 mice were fed diets consisting of 50% calories from lard, 5% from soybean, and 5% from corn oil (HFD), or 50% calories from lard and 10% from BRS oil (HFD + BRS oil diet) for 12 weeks. Six‐week‐old C57BL/KsJ‐db/db mice were fed diets consisting of 16% calories from soybean oil (standard diet), 8% from soybean, and 8% from BRS oil, or 16% from BRS oil for 10 weeks. The BRS oil diets lowered the levels of triacylglycerol, nonesterified fatty acids, and total cholesterol in serum and liver of both of the obese and db/db mice as compared with the HFD and standard diet, respectively. mRNA levels of lipogenesis markers including cluster of differentiation 36, fatty‐acid‐binding protein 1, sterol regulatory element binding protein 1c, fatty‐acid synthase, and solute carrier family 25 member 1 in the liver of the BRS oil groups were lower than those in the liver of the HFD and standard groups in the obese and db/db mice, respectively. On the other hand, fatty‐acid oxidation markers including carnitine palmitoyltransferase 1A, acyl‐CoA dehydrogenase, hydroxylacyl‐CoA dehydrogenase α, and acyl‐CoA oxidase in the liver of the BRS oil groups were higher than those in the liver of the HFD and standard groups in the obese and db/db mice, respectively. Peroxisome proliferator‐activated receptor α mRNA and protein levels increased in the liver and epididymal adipose tissue of the obese and db/db mice fed BRS oil compared with HFD and standard diet, respectively. BRS oil might improve lipid metabolism by inhibiting lipogenesis and promoting fatty‐acid oxidation in HFD‐induced obese and db/db mice.     

Accurate determination of hexanal in beef bouillons by headspace solid‐phase microextraction gas‐chromatography mass‐spectrometry

Lipid oxidation has great impact on the quality of food products through flavor and taste deterioration, reduction in nutritive value, and potential toxicity of the oxidized food components. Flavor and taste deterioration can be easily perceived and it represents one of the major causes of consumer complaints in the food industry. The deterioration of sensory properties is due to the decomposition products of hydroperoxides that easily isomerize and degrade into volatile compounds. Volatile products are responsible for flavor and taste deterioration. In this study, we present the development of the solid‐phase microextraction gas chromatography‐mass spectrometry (SPME‐GC‐MS) technique to quantify low amounts (μg/g range) of secondary oxidation products, i.e. hexanal. The optimization of SPME parameters is a difficult task because of the possibility of further formation of volatile products during analysis. Different parameters such as type of fiber, exposure time of the fiber to the sample headspace and the optimal temperature of absorption have also been investigated. The complete validation of the method was achieved by the determination of linearity, limits of detection and quantification and repeatability. We demonstrated that the SPME method is a valuable tool for the quantification of low amounts of secondary oxidation products such as hexanal. Therefore, this technique can be used to detect early formation of volatiles.     

Low‐Temperature Oxidation of Catocene and Its Influence on the Mechanical Sensitivities of a Fine‐AP/Catocene Mixture

High burning‐rate composite solid propellants with fine ammonium perchlorate (fine‐AP) and catocene have high mechanical sensitivities. The products of fine‐AP and catocene mixtures after low‐temperature exothermic reactions at about 173 °C were analyzed by X‐ray photoelectron spectroscopy (XPS). The result showed that FeO, Fe₂O₃, or FeCl_x were generated during the oxidation of catocene in the fine‐AP/catocene mixture. The mixture of fine‐AP and catocene has high impact and friction sensitivities, whereas the impact sensitivity of the after‐heated fine‐AP/catocene mixture reduced from 88 to 18 % and the friction sensitivity also decreased from 80 to 66 %. The low‐temperature oxidation of catocene is one important incentive for the high mechanical sensitivity of fine‐AP/catocene mixtures.     

Moonlighting Metals: Insights into Regulation of Cyclization Pathways in Fungal Δ6‐Protoilludene Sesquiterpene Synthases

Fungal 1,11 cyclizing sesquiterpene synthases are product specific under typical reaction conditions. However, in vivo expression of certain Δ⁶‐protoilludene synthases results in dual 1,11 and 1,10 cyclization. To determine the factors regulating this mechanistic variation, in‐depth in vitro characterization of Δ⁶‐protoilludene synthases was conducted. Divalent metal ions determine cyclization specificity and this product variability. Promiscuity in metal binding is mediated by secondary metal‐binding sites away from the conserved D(D/E)XX(D/E) motif in sesquiterpene synthases. Phylogenetic analysis revealed a divergent evolution of Basidiomycota trans‐humulyl cation producing sesquiterpene synthases, results that indicate a wider diversity in function than previously predicted. This study provides key insights into the function and evolution of 1,11 cyclizing fungal sesquiterpene synthases.     

Degradation of polyethylene during extrusion. II. Degradation of low‐density polyethylene,linear low‐density polyethylene,and high‐density polyethylene in film extrusion

The degradation of different polyethylenes—low‐density polyethylene (LDPE), linear low‐density polyethylene (LLDPE), and high‐density polyethylene (HDPE)—with and without antioxidants and at different oxygen concentrations in the polymer granulates, have been studied in extrusion coating processing. The degradation was followed by online rheometry, size exclusion chromatography, surface oxidation index measurements, and gas chromatography–mass spectrometry. The degradations start in the extruder where primary radicals are formed, which are subject to the auto‐oxidation when oxygen is present. In the extruder, crosslinking or chain scissions reactions are dominating at low and high melt temperatures, respectively, for LDPE, and chain scission is overall dominating for the more linear LLDPE and HDPE resins. Additives such as antioxidants react with primary radicals formed in the melt. Degradation taking place in the film between the die orifice, and the quenching point is mainly related to the exposure time to air oxygen. Melt temperatures above 280°C give a dominating surface oxidation, which increases with the exposure time to air between die orifice and quenching too. A number of degradation products were identified—for example, aldehydes and organic acids—which were present in homologous series. The total amount of aldehydes and acids for each number of chain carbon atoms were appeared in the order of C5>C4>C6>C7?C2 for LDPE, C5>C6>C4>C7?C2 for LLDPE, and C5>C6>C7>C4?C2 for HDPE. The total amounts of oxidized compounds presented in the films were related to the processing conditions. Polymer melts exposed to oxygen at the highest temperatures and longest times showed the presence dialdehydes, in addition to the aldehydes and acids. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1525–1537, 2004     

Lipid Composition and State of Oxidation of Fortified Infant Flours in Low‐Income Countries Are Not Optimal and Strongly Affected by the Time of Storage

Food fortification is widely used to address the public health problem of nutrient deficiencies. This study's purpose is to assess the lipid profile and nutritional quality of 13 fortified infant flours (FI) collected “in the field” in Africa and Asia after different periods of storage. The lipid content, fatty acid profiles, lipophilic vitamin content, and lipid oxidation state (peroxide values, secondary oxidation products) are determined. Mycotoxins and packaging materials are also characterized. The lipid content averages 9.1 ± 3.5 g/100 g. Fatty acid profiles are dominated by linoleic (43.3 ± 8.8%), oleic (29.5 ± 7.4%), and palmitic acid (17.8 ± 6.7%) and result in an average ω6/ω3 ratio of 12.2 ± 5.9 but with high values for some FI. Very high overages in vitamins A, D, and E are observed in products stored for short periods (1–6 months), whereas FI stored for more than 12 months has insufficient vitamin content. Lipid oxidation is acceptable but for six products presenting excessive peroxide values. Most products are contaminated by low amounts of mycotoxins but only two FI do not abide by the regulation. A strong correlation between peroxide values, hexanal content, and time of storage is observed. Practical Applications: The expiration dates for FI commercialized in low‐income countries should be shortened from 36 to 12 months so as to guarantee their nutritional quality of these functional foods and to abide by the fortified infant flour legislation. Indeed, FI quality significantly decreases over time of storage. The use of high barrier packaging materials must be generalized, although it is a necessary criterion but not sufficient to ensure the long‐term stability of FI. Special attention should be given to reduce lipophilic vitamin overages and to improve their lipid profile, especially the ω6/ω3 ratio, which has to be lower than 15.     

Process Design in World 3.0 – Challenges and Strategies to Master the Raw Material Change

The evolution of global energy supply chains leads to a raw material change in the chemical industry. Despite this change, the value‐added chains of the chemical industry have to keep up their output of diverse high‐quality products desired by the customers. C1 chemistry in combination with suitable conversion technologies yielding olefins and aromatics will play a key role in mastering this challenge. New chemical value‐added chains have to be developed and assessed, resulting in an increasing importance of conceptual process design. All this will take place in what Ghemawat has called the World 3.0, a globally linked but regionally diverse world. This diversity creates further challenges for process design in the chemical industries. A systematic concept to address these challenges is given here, including strategies for optimization and decision support.     

Ultra‐Performance Liquid Chromatography‐Mass Spectrometry Analysis of Free and Esterified Oxygenated Derivatives from Docosahexaenoic Acid in Rat Brain

Docosahexaenoic acid (DHA), a prominent long‐chain fatty acid of the omega‐3 family, is present at high amount in brain tissues, especially in membrane phospholipids. This polyunsaturated fatty acid is the precursor of various oxygenated lipid mediators involved in diverse physiological and pathophysiological processes. Characterization of DHA‐oxygenated metabolites is therefore crucial for better understanding the biological roles of DHA. In this study, we identified and measured, by ultrahigh‐performance liquid chromatography coupled with tandem mass spectrometry, a number of oxygenated products derived from DHA in exsanguinated and nonexsanguinated brains. These metabolites were found both in free form and esterified in phospholipids. Interestingly, both (R)‐ and (S)‐monohydroxylated fatty acid stereoisomers were observed free and esterified in phospholipids. Monohydroxylated metabolites were the main derivatives; however, measurable amounts of dihydroxylated products such as protectin DX were detected. Moreover, exsanguination allowed discriminating brain oxygenated metabolites from those generated in blood. These results obtained in healthy rats allowed an overview on the brain oxygenated metabolism of DHA, which deserves further research in pathophysiological conditions, especially in neurodegenerative diseases.     

Toward a Spatiotemporal Model of Oxidation in Lipid Dispersions: A Hypothesis‐Driven Review

Unsaturated lipids are prone to get oxidized through a sequence of reactions known as lipid oxidation. From a phenomenon considered at the beginning as a mere chemical process and described by the triptych of initiation, propagation, and termination, the vision of lipid oxidation has progressively evolved to further integrate the physical dimension of the phenomenon. Despite tremendous research efforts, however, this sequence of reactions is not yet well understood, especially in lipid dispersions where many facts are still inexplicable and unpredictable under the current paradigm. Here, the aim is to suggest that the main reason why a better understanding has not already been achieved is that the reactional network is not yet organized in a coherent spatiotemporal framework. The novel concepts and hypotheses proposed in this article may help redirecting a significant part of research efforts toward the establishment of a spatially and temporally resolved model of oxidation in dispersed lipids. Practical Application : Predicting how oxidation spreads in lipid dispersions represents a goal of crucial importance for academia but also for industry. Such prediction models would indeed greatly help food manufacturers prevent oxidation by using the most adapted antioxidative strategies for their specific products. To achieve such an objective, it is proposed that the first thing to do is to go beyond the extremely reductive and narrow framework in which this chemical process has been locked in. Indeed, while lipid dispersions are composed of a multitude of lipid colloids, researchers usually consider oxidation at the sole level of an individual droplet or membrane. Instead, lipid oxidation is advocated as a dynamic trafficking of chemical species within large communities of different colloidal objects such as droplets, membranes, or micelles dispersed in water—a system that dubbed “colloidal ecosystem”. This might represent a scale complementary to the scales of individual colloids or molecules that were the sole consideration so far to try to represent lipid oxidation. Only then can one hope to effectively apply modeling and “omics” approaches, as is explained in more details in this article.     

Chemical Synthesis and Gas Chromatographic Behaviour of γ‐Stearidonic (18:4n‐6) Acid

γ‐Stearidonic acid, 18:4n‐6, a potential product of β‐oxidation of arachidonic acid (20:4n‐6), was only recently positively identified in a living organism—a thermophilic cyanobacterium Tolypothrix sp., albeit at low levels, whilst some indirect evidence suggests its wider presence, e.g. in a unicellular marine alga. We have prepared 18:4n‐6 using an iodolactonisation chain‐shortening approach from 22:5n‐6 and obtained its ¹H‐, ¹³C‐, COSY‐ and HSQC NMR spectra, with 18:5n‐3 spectra also recorded for a comparison. The GC and GC‐MS behaviour of its methyl ester was also studied. Like another Δ3 polyunsaturated acid, octadecapentaenoic (18:5n‐3), 18:4n‐6 rapidly yields 2‐trans isomer upon formation of dimethyloxazoline derivative. On a polar ionic liquid phase (SLB‐IL100, 200 °C) the methyl ester could be mistaken for 18:3n‐3, while on methylsilicone phase (BP1, 210 °C) it eluted ahead of 18:3n‐6 and 18:4n‐3, suggesting that when present it may be easily misidentified during GC analysis of fatty acids.