Decrease In Polyunsaturated Fatty Acids Research Articles

Dietary supplementation with nerolidol improves the antioxidant capacity and muscle fatty acid profile of Brycon amazonicus exposed to acute heat stress.

An increase in water temperature in the Amazon River has elicited concerns about commercially important fish species associated with food security, such as matrinxã (Brycon amazonicus). Studies have demonstrated the positive effects of diets supplemented with plant-based products that combat heat stress-induced oxidative damage. The aim of this study was to determine whether dietary supplementation with nerolidol prevents or reduces muscle oxidative damage and impairment of the fillet fatty acid profile of matrinxã exposed to heat stress. Plasma and muscle reactive oxygen species (ROS) and lipid peroxidation (LPO) levels were significantly higher in fish exposed to heat stress compared to fish not exposed to heat stress, while plasma superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity was significantly lower. The total content of saturated fatty acids (SFA) in fillets was significantly higher in fish exposed to heat stress compared to fish not exposed to heat stress, while he total content of polyunsaturated fatty acids (PUFA) was significantly lower. Nerolidol prevented the increase of muscle LPO and plasma ROS and LPO levels in fish exposed to heat stress, and partially prevented the increase in muscle ROS levels. Diets containing nerolidol prevented the inhibition of muscle GPx activity in fish exposed to heat stress, and partially prevented the decrease of plasma GPx activity. The nerolidol-supplemented diet prevented the increase of fillet SFA in fish exposed to heat stress, while partially preventing the decrease of PUFA. We conclude that acute heat stress at 34°C for 72h causes plasma and muscular oxidative damage, and that homeoviscous adaptation to maintain membrane fluidity can represent a negative impact for fish consumers. A nerolidol diet can be considered a strategy to prevent heat stress-induced oxidative damage and impairment of muscle fatty acid profiles.

Changes in Fatty Acid and Volatile Compound Profiles during Storage of Smoked Cheese Made from the Milk of Native Polish Cow Breeds Raised in the Low Beskids.

Simple SummaryCheese, due to its high nutritional value, is an important element of the daily diet of many consumers. About one third of cow milk produced globally is processed into a wide assortment of cheeses. Most of them are produced on a mass scale in industrial conditions. One factor determining cheese quality is the quality of the milk it is made from. The milk of pasture-grazed cows is known to have higher content of compounds benefiting human health. Consumers are increasingly interested in artisanal products, including cheese, manufactured directly on farms or in small, local processing facilities, regarding them as natural, less processed, and free of additives. Milk for the production of this type of cheese usually comes from cows of native breeds kept on family farms. Smoking is one of the oldest traditional methods used to prolong the shelf-life of food. It imparts a pleasant aroma to cheese and improves its palatability. The literature lacks studies on the quality of smoked cheese during storage. The aim of this study is to assess changes in chemical composition and in fatty acid and volatile compound profiles during storage of smoked cheese made from the milk of native Polish cow breeds.This study investigated changes in the proximate chemical composition and profiles of fatty acids and volatile compounds of 12 smoked cheeses made from the milk of native Polish cow breeds used in Beskid Niski. Analyses were performed during the shelf life i.e., in the 1st, 21st, 42nd and 69th day of storage. Studies have shown that thanks to smoking and vacuum-packing, the chemical composition of cheese remained stable throughout the whole shelf-life. Up until the 21st day of storage, there were no statistically significant changes in the profile of fatty acids as well as volatile compounds. Changes were observed only after the mentioned storage time. After 21 days, there was a significant (p < 0.05) and steady decrease (up to day 69) in the proportion of odd-chain (by about 36%), branched-chain (by about 17%) and unsaturated fatty acids (by slightly over 1%). Among unsaturated fatty acids (p < 0.05), however, there was a significant increase in the proportion of monounsaturated fatty acids (by 5%) and a decrease in polyunsaturated fatty acids of nearly 12%. Storage lowered (by 47% in the 69th day of storage) the content of the conjugated linoleic acids (CLA), as well as lowered the n6 to n3 fatty acids ratio. During the 69 days of storage, the content of carboxylic acids increased to more than 50%. In the period from the 42nd to 69th day of cheese storage, the content of butyric acid and hexanoic acids increased twofold, whereas that of octanoic acid increased more than tenfold. Fifty-four volatile compounds were identified in the cheese. The largest group was ketones (34%), whose level decreased during storage, with 2-butanone, 3-hydroxy- (acetoin) and 2-butanone predominating. The research found that due to their low odor threshold, carboxylic acids may have negatively affected the flavor profile of the cheese.

Novel Genomic Regions Associated with Intramuscular Fatty Acid Composition in Rabbits.

Simple SummaryA divergent selection experiment on intramuscular fat (IMF) content was carried out during nine generations in rabbits. The IMF content was successfully improved through generations. Besides, selection for IMF content generated a correlated response on its composition. Association analyses were performed to understand the genetic background of IMF composition using two rabbit lines divergently selected for IMF content. Several genomic regions and genes were identified, revealing the polygenic nature of the intramuscular fatty acid composition in rabbits.Intramuscular fat (IMF) content and its composition affect the quality of meat. Selection for IMF generated a correlated response on its fatty acid composition. The increase of IMF content is associated with an increase of its saturated (SFA) and monounsaturated (MUFA) fatty acids, and consequently a decrease of polyunsaturated fatty acids (PUFA). We carried out a genome wide association study (GWAS) for IMF composition on two rabbit lines divergently selected for IMF content, using a Bayes B procedure. Association analyses were performed using 475 individuals and 90,235 Single Nucleotide Polymorphisms (SNPs). The main objectives were to identify genomic regions associated with the IMF composition and to generate a list of candidate genes. Genomic regions associated with the intramuscular fatty acid composition were spread across different rabbit chromosomes (OCU). An important region at 34.0–37.9 Mb on OCU1 was associated with C14:0, C16:0, SFA, and C18:2n6, explaining 3.5%, 11.2%, 11.3%, and 3.2% of the genomic variance, respectively. Another relevant genomic region was found to be associated at 46.0–48.9 Mb on OCU18, explaining up to 8% of the genomic variance of MUFA/SFA. The associated regions harbor several genes related to lipid metabolism, such as SCD, PLIN2, and ERLIN1. The main genomic regions associated with the fatty acids were not previously associated with IMF content in rabbits. Nonetheless, MTMR2 is the only gene that was associated with both the IMF content and composition in rabbits. Our study highlighted the polygenic nature of the fatty acids in rabbits and elucidated its genetic background.

Effects of repeated deep-frying on fatty acid profiles of potato fries and frying oils: soybean oil, canola oil and their 1:1 blend

Introduction: This study looked at the fatty acid composition changes in potato fries fried in three different types of oils, namely soybean oil (SO), canola oil (CO), and a 1:1 blend of soybean oil and canola oil (SCO), throughout an intermittent frying process of 80 batches in five consecutive days. The study also examined the fatty acid composition changes in SO, CO and SCO during the frying process. Methods: Fat from potato fries (extracted by Soxtec system) and oil samples from the corresponding frying oil were analysed by gas chromatography-mass spectrometer (GC-MS) to examine the fatty acid profile changes during the deep-frying process. Results: Linoleic acid (LA) and a-linolenic acid (ALA) in all three oils decreased, while oleic acid (C18:1), stearic acid (C18:0), palmitic acid (C16:0) and octanoic acid (C8:0) increased. Formation of C18:1 trans fatty acid was observed as the frying time increased. The fatty acid composition of the potato fries was consistent with the fatty acid composition of the corresponding frying oils. Conclusion: Our results showed that blending soybean oil and canola oil did not significantly improve the frying stability of the resulting oil in terms of fatty acid profile. Due to the formation of trans fatty acids and the decrease in polyunsaturated fatty acids, our study also recommends not to use the same frying oil repeatedly and not to consume food products cooked in reused oil.

Protective effects of extra virgin olive oil against storage-induced omega 3 fatty acid oxidation of algae oil

The low oxidative stability of polyunsaturated fatty acids (PUFA) in omega-3 supplements may cause the formation of compounds that may have negative healthy effects. Extra virgin olive oil (EVOO) contains high content of monounsaturated fatty acids (MUFA) and polyphenols, which might improve PUFA oxidative stability when combined with vegetable oils enriched in them. In order to prevent the formation of oxidized compounds and improve the shelf-life of PUFA, different proportions of EVOO (enriched in oleic acid and polyphenols) and algae oil (AO) were studied. For this purpose, both pure oils combined in different proportions were stored under accelerated degradation conditions (40 and 55 °C) for 70 days. Correlations and significant changes in levels of fatty acids composition, phenolic components and oxidation rates during storage time were studied. Throughout storage, higher EVOO quantity at the final mixture was related with less PUFA degradation, where a 27.53% decrease in PUFA of AO passed to less than 12% in a resulting oil of at least 75% of EVOO. PUFA concentration correlated with the formation of secondary peroxides, while MUFA content from EVOO produced a reduction in PUFA degradation. In addition, high secoiridoid levels in mixtures decreased the hydrolysis of triglycerides over the time.

Exploring the impacts of mercury chloride exposure on fatty acids profile, oxidative stress response and histomorphological aspect of Cerastoderma edule detoxifying organs

Mercury chloride (HgCl2) is a highly toxic compound which provokes a wide range of complicated disorders. The present work aimed to investigate the potential effects of HgCl2 toxicity on the redox state, fatty acids composition and histomorphological aspect of Cerastoderma edule (C. edule) gills and digestive gland. To this end, C. edule were exposed to HgCl2 graded concentrations (1, 10 and 100 µg.L−1) for 6 days. Results showed that HgCl2 exposure caused a significant increase in the levels of hydrogen peroxidase (H2O2) and malondialdehyde (MDA). Fatty acids (FA) analysis in the treated gills and digestive glands indicated an increase in saturated and monounsaturated fatty acids and a decrease in polyunsaturated fatty acids, mainly eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. However, the levels of arachidonic (ARA) and linoleic (C18:2n-6) acids were enhanced especially at the sharpest concentration (100 µg/L). In our investigation, we noticed a significant alteration in the estimated desaturases and elongases’ activities in the treated gills as compared to the digestive glands. A concentration-dependent increase in the enzymatic (superoxide dismutase, glutathione peroxidase and catalase) and non-enzymatic (metallothionein, reduced glutathione and vitamin C) antioxidants was also observed in all treated C. edule. The histopathological changes detected in HgCl2-treated gills and digestive glands varied in a concentration-dependent manner. Overall, this work presented novel evidences about the mechanisms of HgCl2-induced toxicity in bivalves.

Effects of superheated steam processing on common buckwheat grains: Lipase inactivation and its association with lipidomics profile during storage

Superheated steam (SS) at 170 °C for 5 min was used to inactivate lipase of common buckwheat grains in this study, which effectively retarded lipid hydrolytic rancidity and maintained lipid nutrition of common buckwheat. Higher stabilities based on lower free fatty acid accumulation and lipase activity were observed in SS-treated buckwheat samples during storage. Meanwhile, SS could suppress oxidation of unsaturated fatty acids (UFA) in buckwheat, significantly retard the increase of saturated fatty acids and the decrease of polyunsaturated fatty acids during storage. Moreover, the lipidomics profile results indicated that SS processing could retard the increased hydrolysis and oxidation of sulfoquinovosyl diacylglycerol, phosphatidylethanolamine, phosphatidylserine and lysophosphatidic acid during storage, while regulate the content of galactolipids. Thus, SS processing could effectively inactivate lipase, suppress UFA oxidation, change glycerolipids and glycerophospholipids subclass metabolism, and consequently retard hydrolytic rancidity and the loss of lipid nutrition in buckwheat during storage. SS processing was proved to effectively protect the quality of buckwheat during storage for the first time.

Tilapia oil, poultry offal oil and their combinations, replacing soybean oil, for tilapia fingerlings

With the objective of evaluating the soybean oil replacement by tilapia oil and poultry oil for Nile tilapia fingerlings, 240 reversed tilapia fingerlings with an individual weight of approximately 0.6 ± 0.11 grams that were stored in 30 aquariums of 50 liters (6T x 5R), in the quantity of 8 units / aquarium, where they were fed with 65% lipid rations containing soybean oil (SO), tilapia oil (TO), poultry oil (PO), and their SO+TO, SO+PO, TO+PO mixtures of equal parts as a lipidic source in practical diets during 50 days. The performance parameters, the carcass composition and the fatty acids content both on the fillet and the innards were verified. The performance, survival, weight gain, and the feeding conversion characteristics were not influenced by the diet. The carcass composition on both the fillet and the innards were not influenced by the source of lipids in the content of moisture and lipids. In general, the fatty acids profile reflected the diets one with the decrease of polyunsaturated fatty acids and the increase of saturated and monounsaturated fatty acids with the replacement. Therefore, tilapia oil, poultry oil, as well as their mixtures can totally or partially replace the soybean oil in diets for Nile tilapia fingerlings without injury to the performance.

Omega-3 Polyunsaturated Fatty Acids Decrease Aortic Valve Disease Through the Resolvin E1 and ChemR23 Axis.

Aortic valve stenosis (AVS), which is the most common valvular heart disease, causes a progressive narrowing of the aortic valve as a consequence of thickening and calcification of the aortic valve leaflets. The beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs) in cardiovascular prevention have recently been demonstrated in a large randomized, controlled trial. In addition, n-3 PUFAs serve as the substrate for the synthesis of specialized proresolving mediators, which are known by their potent beneficial anti-inflammatory, proresolving, and tissue-modifying properties in cardiovascular disease. However, the effects of n-3 PUFA and specialized proresolving mediators on AVS have not yet been determined. The aim of this study was to identify the role of n-3 PUFA-derived specialized proresolving mediators in relation to the development of AVS. Lipidomic and transcriptomic analyses were performed in human tricuspid aortic valves. Apoe-/- mice and wire injury in C57BL/6J mice were used as models for mechanistic studies. We found that n-3 PUFA incorporation into human stenotic aortic valves was higher in noncalcified regions compared with calcified regions. Liquid chromatography tandem mass spectrometry-based lipid mediator lipidomics identified that the n-3 PUFA-derived specialized proresolving mediator resolvin E1 was dysregulated in calcified regions and acted as a calcification inhibitor. Apoe-/- mice expressing the Caenorhabditis elegans Fat-1 transgene (Fat-1tg×Apoe-/-), which enables the endogenous synthesis of n-3 PUFA and increased valvular n-3 PUFA content, exhibited reduced valve calcification, lower aortic valve leaflet area, increased M2 macrophage polarization, and improved echocardiographic parameters. Finally, abrogation of the resolvin E1 receptor ChemR23 enhanced disease progression, and the beneficial effects of Fat-1tg were abolished in the absence of ChemR23. n-3 PUFA-derived resolvin E1 and its receptor ChemR23 emerge as a key axis in the inhibition of AVS progression and may represent a novel potential therapeutic opportunity to be evaluated in patients with AVS.

Combined effect of nutrient and flashing light frequency for a biochemical composition shift in Nannochloropsis gaditana grown in a quasi‐isoactinic reactor

AbstractArtificial lighting may be an interesting opportunity for the cultivation of microalgae as an alternative to natural sunlight. In particular, light emitting diodes (LEDs) can be employed to tailor the lighting to the microalgal culture in a controlled mode in order to create flashing light. In order to establish the effect of the flashing frequency on growth and biochemical composition of a model microalga, a quasi‐isoactinic reactor, in which the light distribution is almost homogeneous, was set up. In this work, it was employed for the cultivation of the heterokont Nannochloropsis gaditana in two growth media with limiting and nonlimiting nutrients. The combined effect of nutrient concentration and flashing frequency on the growth, lipid content, fatty acid content, and pigment content was assessed for the first time. The results indicate that both nutrient concentration and flashing frequency influence the above‐mentioned parameters. In particular, under flashing light conditions, an increase of lipid content and a decrease of polyunsaturated fatty acids (PUFAs) and chlorophyll are observed when nutrients are deficient, while the opposite effects are shown when nutrients are abundant.

Sustitución del aceite de soya por aceite de vísceras de aves en raciones para alevinos de tilapia del Nilo

This experiment was carried out with the objective of evaluating the soybean oil replacement by poultry fat for Nile tilapia fingerlings. Two hundred reversed tilapia fingerlings with an individual weight of approximately 0,6 ± 0,11 grams were stocked in 50-liter aquariums, with 8 fishes in each experimental unity, where they were fed with 6,52% lipid rations containing 0, 25, 50, 75, 100 percent of poultry oil replaced by soybean oil as a lipid source in their diets during 50 days. The performance parameters, the carcass composition and the content of fatty acids on both the fillet and the innards were verified. The performance, survival, weight gain and feeding conversion characteristics were not influenced by the diet. The carcass composition was influenced by the lipid source in the moisture content and lipids. In general, the fatty acids profile reflected the diets one with a decrease of polyunsaturated fatty acids and an increase of saturated and monounsaturated fatty acids with the replacement. Therefore, the poultry oil can partially or totally replace the soybean oil in practical diets for Nile tilapia fingerlings without injury to the performance.

Effects of membrane fatty acid composition on cellular metabolism and oxidative stress in dermal fibroblasts from small and large breed dogs.

There is ample evidence that cell membrane architecture contributes to metabolism and aging in animals; however, the aspects of this architecture that determine the rate of metabolism and longevity are still being debated. The 'membrane pacemaker' hypothesis of metabolism and of aging, respectively, suggest that increased lipid unsaturation and large amounts of polyunsaturated fatty acids (PUFAs) in cell membranes increase the cellular metabolic rate as well as the vulnerability of the cell to oxidative damage, thus increasing organismal metabolic rate and decreasing longevity. Here, we tested these hypotheses by experimentally altering the membrane fatty acid composition of fibroblast cells derived from small and large breed dogs by incubating them in a medium enriched in the monounsaturated fatty acid (MUFA) oleic acid (OA, 18:1) to decrease the total saturation. We then measured cellular metabolic parameters and correlated these parameters with membrane fatty acid composition and oxidative stress. We found that cells from small dogs and OA-incubated cells had lower maximal oxygen consumption and basal oxygen consumption rates, respectively, which are traits associated with longer lifespans. Furthermore, although we did not find differences in oxidative stress, cells from small dogs and OA-treated cells exhibited reduced ATP coupling efficiency, suggesting that these cells are less prone to producing reactive oxygen species. Membrane fatty acid composition did not differ between cells from large and small dogs, but cells incubated with OA had more monounsaturated fatty acids and a higher number of double bonds overall despite a decrease in PUFAs. Our results suggest that increasing the monounsaturation of dog cell membranes may alter some metabolic parameters linked to increases in longevity.

Cellular toxicity mechanisms of lambda-cyhalothrin in Venus verrucosa as revealed by fatty acid composition, redox status and histopathological changes

Abstract Lambda-cyhalothrin (λ-cyh), a synthetic pyrethroid type II, is one of the most toxic xenobiotics to aquatic organisms, which leads to a number of complex toxicological syndromes. The present study aimed to assess the adverse effects of λ-cyh, on fatty acid (FA) composition, redox status, and the histopathology aspect of Venus verrucosa digestive gland under an exposure to a series of concentrations (100, 250 and 500 µg/L). An increase of saturated fatty acid (SFAs) levels and a decrease of polyunsaturated fatty acids (PUFAs) content, mainly eicosapentaenoic (C20: 5n − 3, EPA) and docosahexaenoic (C22: 6n − 3, DHA) acids, were observed in λ-cyh-treated digestive gland. Moreover, our data indicated an alteration in arachidonic acid (C20:4n − 6, ARA) level. The exposure to the highest dose of λ-cyh promoted oxidative stress with an increase of malondialdehyde (MDA), advanced oxidation protein product (AOPP), metallothionein (MT) and hydrogen peroxide (H2O2) levels. A significant decrease in enzymatic (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)) and non-enzymatic (reduced glutathione (GSH), vitamin C and non-protein-SH (NPSH)) antioxidants was showed in treated groups. Moreover, acetylcholinesterase (AChE) activity was inhibited with the increase in λ-cyh concentration. Our biochemicals results have been confirmed by the histopathological observations. Overall, our results indicated the toxic effect of λ-cyh on the redox status of V. verrucosa digestive gland and highlighted the usefulness of determining FA composition in the better understanding of λ-cyh toxicity.

N-3 Polyunsaturated Fatty Acids Decrease Long-Term Diabetic Risk of Offspring of Gestational Diabetes Rats by Postponing Shortening of Hepatic Telomeres and Modulating Liver Metabolism.

The long-term influence of gestational diabetes mellitus (GDM) on offspring and the effect of omega-3 polyunsaturated fatty acids (n-3 PUFA) on GDM offspring are poorly understood. We studied the long-term diabetic risk in GDM offspring and evaluated the effect of n-3 PUFA intervention. Healthy offspring rats were fed standard diet (soybean oil) after weaning. GDM offspring were divided into three groups: GDM offspring (soybean oil), n-3 PUFA adequate offspring (fish oil), and n-3 PUFA deficient offspring (safflower oil), fed up to 11 months old. The diabetic risk of GDM offspring gradually increased from no change at weaning to obvious impaired glucose and insulin tolerance at 11 months old. n-3 PUFA decreased oxidative stress and inflammation in the liver of older GDM offspring. There was a differential effect of n-3 PUFA and n-6 PUFA on hepatic telomere length in GDM offspring. Non-targeted metabolomics showed that n-3 PUFA played a modulating role in the liver, in which numerous metabolites and metabolic pathways were altered when GDM offspring grew to old age. Many metabolites were related to diabetes risk, such as α-linolenic acid, palmitic acid, ceramide, oxaloacetic acid, tocotrienol, tetrahydro-11-deoxycortisol, andniacinamide. In summary, GDM offspring exhibited obvious diabetes risk at old age, whereas n-3 PUFA decreased this risk.

Causal Link between n-3 Polyunsaturated Fatty Acid Deficiency and Motivation Deficits

Reward-processing impairment is a common symptomatic dimension of several psychiatric disorders. However, whether the underlying pathological mechanisms are common is unknown. Herein, we asked if the decrease in the n-3 Polyunsaturated Fatty Acids (PUFAs) lipid species, consistently described in these pathologies, could underlie reward-processing deficits. We show that reduced n-3 PUFA biostatus in mice leads to selective motivational deficits. Electrophysiological recordings revealed increased collateral inhibition of dopamine D2 receptor (D2R)-expressing medium spiny neurons (iMSNs) onto dopamine D1 receptor-expressing (d)MSNs in the nucleus accumbens, a main brain region for the modulation of motivation. Strikingly, transgenically preventing n-3 PUFA deficiency selectively in D2R-expressing neurons normalizes MSNs collateral inhibition and enhances motivation. These results constitute the first demonstration of a causal link between a behavioral deficit and n-3 PUFA decrease in a discrete neuronal population and suggest that lower n-3 PUFA biostatus in psychopathologies could participate to the etiology of reward-related symptoms.

Thermo-degradative changes of rapeseed and sunflower oils during deep-frying French fries

The purpose of this study was to investigate changes in TPCs, acid value and peroxide value as well as fatty acids composition in edible oils during french fries production. Lower TPCs content was found in rapeseed oil (3.3%) and the threshold (24%) was achieved on the fourth day. The total time for the deterioration of deep-frying rapeseed oil was 23½ hours. On the contrary, in fresh sunflower oil at the first day was TPCs content 5.5% and the limit of 24% was reached on the third day. The total time for the deterioration of deep-frying sunflower oil was 17½ hours. The results indicated significant differences (&lt;0.05) in TPCs content between rapeseed and sunflower oils during deep-frying process. At the beginning of deep-frying French fries in rapeseed oil, the acid number was 0.374 mg KOH.g-1 and 1.271 mg KOH.g-1 at the fourth day of deep-frying. The measured peroxide value was 4.3 mEq O2.kg-1 at the beginning and at the end of deep-frying 10.5 mEq O2.kg-1. The initial peroxide and acid values were higher in sunflower oil compared with rapeseed oil, respectively. It should be note, then the acid values and peroxide values, respectively, in the two fresh oils used in this study were below the limit of refined oil according to Slovak legislation (peroxide value - not more than 10 mEq O2.kg-1, acid value - not more than 0.6 mg KOH.g-1). However, detected values varied during deep-frying process. Monounsaturated fatty acids were predominantly observed in fresh rapeseed oil (61.22%) wherever in sunflower oil they were much lower (29.77%). A slight increase of MUFA was found in both oils. The initial content of saturated fatty acids in rapeseed oil was 6.94%, in fresh sunflower oil was observed slightly higher content of SFA (10.37%). The major groups of fatty acids in fresh sunflower oil were polyunsaturated fatty acids (PUFA) which have in principle a significant effect on oil deterioration. A slight decrease of PUFA was observed in both oils throughout the frying period. The content of PUFA was reduced by about 9.42% in rapeseed oil and by 10.8% in sunflower oil. The initial content was 28.14% and 58.91%, respectively.

Effects of whole linseed supplementation and treatment duration on fatty acid profile and endogenous bioactive compounds of beef muscle

Diet supplementation with oilseeds is known to improve the fatty acid profile of meat, but few studies have been carried out to determine the time required for the incorporation of a significant quantity of n-3 polyunsaturated fatty acids (PUFA) into meat from steers. Therefore, the present study aimed to assess the effects of linseed supplementation and feeding duration on the fatty acid profile, cholesterol and bioactive compounds of bovine meat. In total, 54 Friesian steers were randomly allocated during the finishing period into six experimental treatments following a 2×3 factorial design. The six treatments consisted of two diets, the control diet (CO) with no supplemental fat and the linseed diet (LS) containing 10% whole linseed, fed 40, 75 or 120 days before slaughter. At the end of each finishing period, steers from the CO and LS groups were slaughtered. After 8 days of ageing chemical analysis, the fatty acid profile, cholesterol content and bioactive compounds were determined from the longissimus thoracis muscle. Including linseed in the diet increased the content of monounsaturated fatty acids, CLA and n-3 PUFA, and reduced the proportion of saturated fatty acids and n-6 PUFA. The percentage of myristic fatty acid increased with the duration of feeding, regardless of diet and a decrease in PUFA and n-6 PUFA was observed in the CO and LS diets, respectively. Furthermore, meat from steers fed linseed showed an increased percentage of n-3 PUFA, linolenic acid, and EPA from 40 to 75 days of feeding, whereas vaccenic acid, CLA 9c,11t, and total CLA increased from 40 and 75 days but declined at 120 days. Beef from the linseed group had a higher content of bioactive substances such as creatine, carnosine and anserine than beef from the control group. The duration of feeding significantly affected the creatine concentrations, with an increase in the LS group from 40 to 75 days of feeding. Feeding linseed did not modify the cholesterol content, on average and the lowest cholesterol content was found in meat after 75 days of linseed administration. This study demonstrates that a short-term diet manipulation is sufficient to improve the nutritional properties of meat, including n-3 PUFA and bioactive compounds.

Integrated Biodiesel and Biogas Production from Chlorella sorokiniana: Towards a Sustainable Closed-Loop through Residual Waste Biodegradation

To date, more effort has been put towards biodiesel production using algal lipid, while less attention has been paid on biogas production. In this paper, we used the accumulated biomass of Chlorella sorokiniana cultivated under nitrogen stress in columns bioreactors with 120 L working volume to produce biodiesel from the extracted neutral lipids and biogas from the residual biomass. The accumulated neutral lipids were 14%, 17% and 21% for cultures containing 100%, 50% and 0.0% NaNO3 concentration respectively. The highest net accumulated methane yield was 315 ml g-1 volatile solids from the residual biomass after lipid extraction of the 50% NaNO3 culture. The fatty acid profile shows a significant increase of saturated fatty acids by 40.5% and 54.1% in nitrogen-deficient cultures 50% NaNO3 and 0.0% NaNO3 respectively and sharply decrease in poly-unsaturated fatty acids by 54.2% under complete deficiency of nitrogen (0.0% NaNO3). The percent of the produced biodiesel through trans esterification was 95% with high cetane value 61 and a high percentage of palmitic acid 37% which reflect high efficiency and stability of the produced biodiesel. The biomethane potential for microalgae (Chlorella sorokiniana) and macroalgae (Laminaria japonica) were 255 and 173 mL g-1 VS respectively under the same conditions.

Enhancement of thermal stability of soybean oil by blending with tea seed oil

Frying accelerates oil deterioration through several chemical reactions, particularly lipid oxidation. Soybean oil (SBO), the polyunsaturated fatty acid (PUFA) rich oil, is prone to thermal degradation. Nevertheless, tea seed oil (TSO), mainly consisting of monounsaturated fatty acids (MUFA), is quite stable. This work aimed to elucidate thermal stability of SBO as affected by TSO blending at varying volume ratios. After frying for several repeated cycles, SBO/TSO blends with the ratios of 70:30, 60:40 and 50:50 showed lower total oxidative degree than SBO alone. FTIR spectra suggested less cis C=C deformation of the SBO blended with TSO, and the 60:40 SBO/TSO blend contained the lowest secondary oxidation products. Along frying, less change in viscosity (color) was found for the 60:40 and 50:50 (60:40) SBO/TSO blends. Improved thermal stability of the blended oils was expected due to the decrease in PUFA and increase in phenolic content, and this study suggested that the 60:40 SBO/TSO blend showed the highest stability.

Functions of PKS Genes in Lipid Synthesis of Schizochytrium sp. by Gene Disruption and Metabolomics Analysis.

Schizochytrium sp. is a kind of marine microalgae with great potential as promising sustainable source of polyunsaturated fatty acids (PUFAs). Polyketide synthase-like (PKS synthase) is supposed to be one of the main ways to synthesize PUFAs in Schizochytrium sp. In order to study the exact relationship between PKS and PUFA biosynthesis, chain length factor (CLF) and dehydrogenase (DH) were cloned from the PKS gene cluster in Schizochytrium sp., then disrupted by homologous recombination. The results showed that DH- and CLF-disrupted strains had significant decreases (65.85 and 84.24%) in PUFA yield, while the saturated fatty acid (SFA) proportion in lipids was slightly increased. Meanwhile, the disruption of CLF decreased the C-22 PUFA proportion by 57.51% without effect on C-20 PUFA accumulation while DH-disrupted mutant decreased the production of each PUFA. Combined with analysis of protein prediction, it indicated that CLF gene exerted an enormous function on the carbon chain elongation in PUFA synthesis, especially for the final elongation from C-20 toC-22 PUFAs. Metabolomics analysis also suggested that the disruption of both genes resulted in the decrease of PUFAs but increase of SFAs, thus weakening glycolysis and tricarboxylic acid (TCA) cycle pathways. This study offers a broad new vision to research the mechanism of PUFA synthesis in Schizochytrium sp.