Total Fatty Acid Composition Research Articles

Fatty acid compositions and tocopherol concentrations in the oils of 11 varieties of walnut (Juglans regia L.) grown at Xinjiang, China

SUMMARYTo confirm the fatty acid compositions and tocopherol concentrations in walnut oil, 11 varieties of walnut (Juglans regia L.) were collected from the Jackwood Experiment Station, Xinjiang Academy of Forestry during harvest in 2010, 2011, and 2012. Total oil was extracted, and the total fatty acid composition of each oil, including saturated fatty acids (SFA), unsaturated fatty acids (UFA), mono-unsaturated fatty acids (MUFA), and poly-unsaturated fatty acids (PUFA), were analysed by gas chromatography, while tocopherol concentrations were measured by high-performance liquid chromatography. The results showed that the total UFA content was > 91% (w/w) in all 11 varieties of walnut. Linoleic acid (18:2) was the dominant UFA, varying from 57.6% (w/w) in ‘XJ020’ to 67.7% (w/w) in ‘XJ004’, whereas concentrations of linolenic acid (18:3) ranged from 9.7% (w/w) in ‘XJ017’ to 19.2% (w/w) in ‘XJ020’. Compared to all other walnut varieties, ‘XJ020’ had the highest concentration of total UFAs [93.7% (w/w)]. Moreover, tocopherol concentrations ranged from 0.04–0.34 mg ml−1 in the walnut oils. γ-Tocopherol was dominant and ranged from 0.033–0.328 mg ml−1, while δ-tocopherol accounted for 0.006–0.038 mg ml−1. No α-tocopherol was detected in any walnut oil. This work contributes to our knowledge on the nutritional properties of walnut oils and will assist in the selection of walnut varieties for a healthy diet.

Spatial, seasonal, and within-plant variation in total fatty acid content and composition in the brown seaweeds Dictyota bartayresii and Dictyopteris australis (Dictyotales, Phaeophyceae)

We investigated the spatial, seasonal, and within-plant variation in total fatty acids (TFA) and fatty acid (FA) composition in the brown seaweeds Dictyota bartayresii sampled from Nelly Bay, Orpheus Island, and Kissing Point (Northern Queensland, Australia) and Dictyopteris australis sampled from Nelly Bay. Both species were present year round, but with no consistent seasonal pattern in plant size, and had an annualized mean content of TFA of 5 % dry weight (dw) that is among the highest recorded for seaweeds. For Dictyota, larger plants had a higher content of TFA and a higher proportion of polyunsaturated omega-3 FA (PUFA(n-3)) than smaller plants, while for Dictyopteris, the TFA content and the proportion of PUFA(n-3) were unrelated to plant size. TFA in Dictyota varied considerably between locations (~40 %) (3.5–5.5 % dw) and to a lesser degree between seasons (~10 %) with a lower content of TFA and higher proportion of PUFA(n-3) in winter. Dictyopteris had an ~10 % higher content of TFA in winter but with no seasonal pattern in the composition of FA. There was also within-plant variation in FA, as TFA decreased from the tips toward the base in both species, and in Dictyopteris, the tips had a higher proportion of saturated FA (SFA) and PUFA(n-3) than the base. The presence of site- and species-specific variation in the content and composition of fatty acids reinforces the need for detailed analyses of the biochemical profile of seaweed biomass, including their extracts or purified compounds, if the focus is nutritional applications based on lipids.

Degree of oxidation depending on the positional distribution of linolenic acid in perilla oil and interesterified products

Interesterified perilla oil (IPO) was produced from rearrangement of fatty acids in perilla oil (PO) using Lipozyme RM IM-catalyzed interesterification. IPO showed a total fatty acid composition similar to PO; however, the positional distributions of ω-3 linolenic acid (ω-3 Ln, ALA) of these two oils were different. Thermal oxidation was performed at 40°C in the dark and oxidative stabilities of PO and IPO were investigated using 1H NMR. After 20 days of oxidation, the concentration of ALA in IPO (47.9±1.3%) was significantly (p<0.05) higher than in PO (40.4±0.6%). IPO (40.6±5.5 mM oil) produced significantly (p<0.05) lower amounts of aldehydes (secondary oxidation products) than PO (61.6±2.0 mM oil). GC and HPLC results showed that the distribution of ALA in the LnLnLn molecule within TAG species was the main reason for improvement in the oxidative stability of IPO.

Supercritical fluid extraction of oil from muskmelon (Cucumis melo) seeds

The objective of this present study was to develop a suitable supercritical fluid extraction (SFE) method for extraction of oil from muskmelon seed (Cucumis melo). A Box–Behnken response surface design was applied to investigate and optimize the process variables (pressure, temperature, CO2 flow rate and time) on the yield of muskmelon seed oil. A second-order polynomial equation was developed to express the oil yield as a function of independent variables. The maximum oil yield (48.11%) was procured when SFE was carried out at 44MPa of pressure, 49°C of temperature, 0.64g/min of CO2 flow rate and 81min of extraction time. The total yield and fatty acids composition of muskmelon seed oil extracted by SFE was similar to that of oil extracted by Soxhlet extraction. Physicochemical properties of the oil at optimal SFE condition showed that the extracted oil could be adopted as food oil supplement. The experimental results indicated that SFE technique reduced the solvent consumption and extraction time with no adverse effect on the extraction yield and fatty acid composition of the oil.

Lipidomic analysis of fats and oils – a lot more than just omega‐3

Edible oils and fats are among the most abundant cooking ingredients in the world, and are an important part of a healthy balanced diet, especially if they are high in omega‐6 and omega‐3 polyunsaturated fatty acids. Rather than just the total fatty acid compositions, the analysis of individual lipid species within these oils and fats has become increasingly important. Within the past decade several mass spectrometric lipidomics methods have been adapted and applied to the analysis of edible oils and fats. These methodologies are vital for the analysis of a plethora of lipid species that will be important for numerous health and sustainability issues in the future.

Comparison of Oxidative Stability among Edible Oils under Continuous Frying Conditions

The stability of camellia oil (saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid = 1:7:1) after frying potatoes was compared with palm oil (saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid = 4:4:1) and peanut oil (saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid = 2:4:4). Oil samples were evaluated for acid value, iodine value, peroxide value, p-anisidine value, total oxidation value, tocopherols content, and fatty acids composition. There was the least change in fatty acid composition in camellia oil among the three edible oils. The α-tocopherol was more vulnerable to heat degradation than γ-tocopherol and δ-tocopherol, and α-tocopherol was completely degraded before the whole frying process was done for palm and peanut oils. The oxidative stabilities of the three edible oils were in the order of camellia oil > palm oil > peanut oil. The oxidative stability was mainly determined by the calculated oxidizability value related to fatty acid composition, and when calculated oxidizability values were similar, the tocopherol contents of edible oils would be a key factor in affecting their oxidative stabilities.

Oxidation and antioxidative effects of rosemary extract and catechin on enzymatically modified lipids containing different total and positional fatty acid compositions

The oxidative stabilities of enzymatic modified lipids (EMLs) were studied using pine nut oil (PN) and palm stearin (PS) as substrates (w/w, 40:60; 30:70) vs. a physical blend (PB). The amount of pinolenic acid (PLA) at the sn-2 position in EML was increased to 5.5% compared to 0.8% in PB. The acid, peroxide, p-anisidine, and TBARS values were used to measure the oxidative stability of EML and PB. After 30 days of oxidation, only 1.5 and 0.7% of total PLA at sn-2 position PLA were detected in EML of PN:PS 40:60 and PN:PS 40:60, respectively. EMLs were more vulnerable to oxidization than PB. Different concentrations of rosemary (1,000 and 2,000 mg/kg) and catetchin (400 and 800 mg/kg) were added to EMLs to reduce the oxidation level. Results indicated that these two antioxidants deterred the extent of oxidation in EMLs.

Contribution to the establishment of a protected designation of origin for Meknès virgin olive oil: A 4-years study of its typicality

Protected designations of origin (PDO) constitute, nowadays, one of the most important differentiation strategies used for the promotion and commercialization of virgin olive oil (VOO). Obtaining these distinctive labels entails a deep study of the inherent features and characteristics of a VOO linked to a given geographical production area. The aim of this study was to perform the physicochemical and sensorial quality characterization of Meknès VOO, as well as the determination of its compositional profile. Thus, a total of 298 olive oil samples from Picholine marocaine cultivar, obtained from 12 industrial olive oil mills, located in three sub-areas of Meknès region, were analyzed over four consecutive seasons, paying particular attention to the determination of physicochemical quality indices, sensorial evaluation, total phenol content, pigment content, tocopherol and fatty acid composition. Results show that, besides an interannual variation, VOOs from Meknès region are characterized by high physicochemical and sensory quality, as well as a homogeneous composition regardless of the production sub-area.

Repeated intratracheal instillation of PM10 induces lipid reshaping in lung parenchyma and in extra-pulmonary tissues.

Adverse health effects of air pollution attributed mainly to airborne particulate matter have been well documented in the last couple of decades. Short term exposure, referring to a few hours exposure, to high ambient PM10 concentration is linked to increased hospitalization rates for cardiovascular events, typically 24 h after air pollution peaks. Particulate matter exposure is related to pulmonary and cardiovascular diseases, with increased oxidative stress and inflammatory status. Previously, we have demonstrated that repeated intratracheal instillation of PM10sum in BALB/c mice leads to respiratory tract inflammation, creating in lung a condition which could potentially evolve in a systemic toxic reaction. Additionally, plasma membrane and tissue lipids are easily affected by oxidative stress and directly correlated with inflammatory products. With this aim, in the present investigation using the same model, we analyzed the toxic potential of PM10sum exposure on lipid plasma membrane composition, lipid peroxidation and the mechanisms of cells protection in multiple organs such as lung, heart, liver and brain. Obtained results indicated that PM10 exposure led to lung lipid reshaping, in particular phospholipid and cholesterol content increases; concomitantly, the generation of oxidative stress caused lipid peroxidation. In liver we found significant changes in lipid content, mainly due to an increase of phosphatidylcholine, and in total fatty acid composition with a more pronounced level of docosahexaenoic acid; these changes were statistically correlated to lung molecular markers. Heart and brain were similarly affected; heart was significantly enriched in triglycerides in half of the PM10sum treated mice. These results demonstrated a direct involvement of PM10sum in affecting lipid metabolism and oxidative stress in peripheral tissues that might be related to the serious systemic air-pollution effects on human health.

Effect of Triple Superphosphate on Growth, Total Chlorophyll Content, Essential Oil and Fatty Acid Compositions in Shoots of Coriander (Coriandrum sativum L.)

The effect of different doses of triple superphosphate (TSP), 100, 200, and 400 kg P ha-1 on growth, chlorophyll content, and essential oil and fatty acid composition was evaluated in shoots of coriander (Coriandrum sativum L.) grown in a pot experiment under nursery conditions. The application of TSP to 6 weeks-old seedlings induced an increase in shoot height, shoot dry weight, the chlorophyll and total fatty acid contents. However, phosphate fertilizer did not affect the total essential oil content, expressed as % of dry weight. The major constituents of the essential oils are decanal, aromadendrene and a-cadinol. The total content of sesquiterpene hydrocarbons was strongly increased under 200 kg P ha-1 (1.9-fold). The essential oil components aromadendrene, cadalene, a-copaene, a-octan-2-ol and n-decanol, (E)-nerolidol, (E,E)-2,4-decadienal, and myrtenyl acetate, were also increased under phosphate fertilization. Threfore, triple superphosphate application induced changes in the composition of essential oils and fatty acids in coriander shoots, and significantly increased the terpenes and total lipid contents.

Improved fatty acid analysis of conjugated linoleic acid rich egg yolk triacylglycerols and phospholipid species.

Reports from chicken conjugated linoleic acid (CLA) feeding trials are limited to yolk total fatty acid composition, which consistently described increased saturated fatty acids and decreased monounsaturated fatty acids. However, information on CLA triacylglycerol (TAG) and phospholipid (PL) species is limited. This study determined the fatty acid composition of total lipids in CLA-rich egg yolk produced with CLA-rich soy oil, relative to control yolks using gas chromatography with flame ionization detection (GC-FID), determined TAG and PL fatty acid compositions by thin-layer chromatography-GC-FID (TLC-GC-FID), identified intact PL and TAG species by TLC-matrix-assisted laser desorption/ionization mass spectrometry (TLC-MALDI-MS), and determined the composition of TAG and PL species in CLA and control yolks by direct flow infusion electrospray ionization MS (DFI ESI-MS). In total, 2 lyso-phosphatidyl choline (LPC) species, 1 sphingomyelin species, 17 phosphatidyl choline species, 19 TAG species, and 9 phosphatidyl ethanolamine species were identified. Fifty percent of CLA was found in TAG, occurring predominantly in C52:5 and C52:4 TAG species. CLA-rich yolks contained significantly more LPC than did control eggs. Comprehensive lipid profiling may provide insight on relationships between lipid composition and the functional properties of CLA-rich eggs.

Fatty acids composition and food consumption among reindeer herders and urban inhabitants of the European North of Russia

The goal of this study was to examine the fatty acid (FA) composition of the total plasma lipids of the native inhabitants of the Russian European North, taking into consideration the differences in lifestyles and nutritional habits as well as the interrelationship between the plasma FA profile and nutrition. In total, 78 native residents of the Russian European North (61 men and 17 women) from two regions of Komi Republic of Northern Russia (Izhma settlement and city Syktyvkar), aged 25-45 years, were included in this study. The Izhma group consisted of reindeer herders (17 men and 17 women). The comparison group (44 men) consisted of citizens of Syktyvkar. Venous blood plasma after overnight fasting was used for analysis of glucose, cholesterol, triglycerides, vitamins and total FA composition. A modified questionnaire 'Seafood and the health of the people of the North' was used for the assessment of nutrition. The levels of total FAs in the blood plasma of Indigenous inhabitants of Russian European North were at the lower border of the reference range. In the Izhma group, levels of n-3 eicosapentaenoic acid (EPA) (1.3/0.9-1.8; p<0.001) and docosahexaenoic acid (DHA) (2.2/1.5-2.8; p=0.025), n-7 palmitoleic FA (2.3/1.9-2.5; p<0.001) were higher than in the Syktyvkar group. At the same time, levels of n-6 linoleic acid (32.1/29.2-35.5; p=0.003) were significantly lower in the male reindeer herders of Izhma. Comparison of the nutritional habits of both groups revealed larger consumption of fish, meat and reindeer fat (p<0.001), eggs (p=0.004), high-carbohydrate products (white bread (p=0.033) and macaroni (p<0.001)) by reindeer herders of Izhma. The participants in the urban group demonstrated higher consumption of fruits (p<0.001), butter (p=0.013), cultured milk foods (p=0.010) and vegetables (p=0.009). The results of the study showed more beneficial n-6/n-3 FA ratios in reindeer herders of Russian European North than in urban inhabitants. Higher plasma polyunsaturated n-3 FA (EPA, DHA) levels in reindeer herders who had more fish in their diet were demonstrated. In addition, inland reindeer herders showed higher palmitoleic acid levels and lower linoleic acid levels in blood total lipids than urban inhabitants. The nutritional features and environmental conditions were assumed to have the greatest effects on plasma FA profiles and lipid metabolism in the Indigenous inhabitants of Russian European North.

Lipids and fatty acid composition of particulate matter in the North Atlantic: importance of spatial heterogeneity, season and community structure

Lipid class profiles and total fatty acid composition of particulate matter were studied in the northeast Atlantic during the spring bloom and fall. Eddies of known physical and chemical properties were sampled at different depths. HPLC pigment data were used to characterize the phytoplankton communities. In spring, a dominance of prymnesiophytes was recorded at all depths, while in fall prochlorophytes dominated near the surface and prymnesiophytes only at deep chlorophyll maximum. Lipid classes included triglycerides, sterols, glycolipids and phospholipids. A differential relationship between phytoplankton abundance and lipid accumulation was observed: spring lipid concentrations were positively related to phytoplankton biomass, while fall particulate lipid did not show any relationship. The main feature was a northward increase in lipid concentrations unrelated to the mesoscale hydrological structures. Polar lipids dominated over neutral acyl-glycerols with phospholipids dominating over glycolipids in spring, while glycolipids dominated in fall. This resulted from different nutrient availability with a dominance of flagellates associated with mesotrophy in spring and of picophytoplankton associated with oligotrophy in fall. In terms of fatty acids, factorial correspondence analyses illustrate the influence of seasonally changing assemblages: (1) in spring, the main source of variability was the bloom with an opposition between bloom sites characterized by n-3 and n-6 PUFA, and more detrital deep samples characterized by saturated, monoenoic and branched acids; (2) fall fatty acid profiles were similar at all depths and very close to those observed for spring deep samples. Comparison of pigment and fatty acids using redundancy analysis suggested that pelagophytes were linked to saturated and branched acids. It also showed that prymnesiophytes and prochlorophytes were significantly associated with n-6 and n-3 PUFA. The spring period illustrated the complexity of these relationships with dinoflagellates and prymnesiophytes linked with n-3 PUFA, diatoms linked with palmitoleic and myristic acids, and pelagophytes linked with n-6 PUFA and higher-chain-length monoenes.

The effect of enzymatic interesterification on the physico-chemical properties and thermo-oxidative stabilities of beef tallow stearin and rapeseed oil blends

Beef tallow stearin (BTS) was blended with rapeseed oil (RSO) and the blends: 40 % BTS + 60 % RSO, 30 % BTS + 70 % RSO, 20 % BTS + 80 % RSO were interesterified using immobilized lipases from Rhizomucor miehei (Lipozyme IM) and Candida antarctica (Novozym 435) as the catalysts. The starting blends and the products of interesterifications were quantitatively separated into the triacylglycerol and non-triacylglycerol fractions containing free fatty acids (FFA) and of mono- and di-acylglycerols. It has been found that after interesterification the contents of the FFA and of MAG and DAG increased. The slip melting temperatures and solid fat contents of triacylglycerols separated from interesterified samples decreased if compared with non-esterified blends. The DSC melting profiles of the blends before and after interesterification were substantially different. The total fatty acid compositions of fats before and after interesterifications remained unchanged. Their distributions into sn-2 and sn-1,3 positions were close to random when Novozym 435 was used. When Lipozyme IM was used, the fatty acid composition at sn-2 position remained practically unchanged compared with the starting blend. Using the DSC and PDSC techniques, the oxidative stabilities of the fats before and after interesterification were also characterized. The interesterified blends were less resistant on thermo-oxidative degradation than the non-esterified ones.

Monthly variation of total lipid and fatty acid contents of Atlantic bonito, Sarda sarda (Bloch, 1793) of Black Sea

SummaryThis study represents significant monthly variations of total lipid and fatty acid composition of muscle and liver tissue of Black Sea bonito (P &lt; 0.05). Average total lipids of bonito muscle and liver were 8.4% and 25.1%, respectively, and the highest polyunsaturated fatty acid (PUFA) was observed in September and March as 52.9% and 46.6%, respectively. Bonito muscle was found to contain good amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in a range of 252.0–1169.1 mg/100 g and 712.1–3324.1 g/100 g, respectively. Higher levels were found in liver at 3323.3 mg/100 g for EPA and 6996.5 mg/100 g for DHA. Although 25–100 g edible muscle is necessary to reach 1 g per day of EPA+DHA requirement for a healthy diet, only 9.8–87.9 g of bonito liver is enough to cover the recommended daily amount for these fatty acids. The results indicate that bonito livers constitute a rich and underexploited source of PUFAs.

A high-performance direct transmethylation method for total fatty acids assessment in biological and foodstuff samples

Isolation is the main bottleneck in the analysis of fatty acids in biological samples and foods. In the last few decades some methods described direct derivatization procedures bypassing these steps. They involve the utilization of methanolic HCL or BF3 as catalysts, but several evidences from previous works suggest these reagents are unstable, lead to the formation of artifacts and alter the distribution of specific compounds as hydroxy fatty acids or CLA. However, the main issue is that they are excellent esterification reagents but poor in transterification, being not suitable for the analysis of all lipid classes and leading to erroneous composition quantitations. The present research work is a comprehensive comparison of six general methylation protocols using base, acid or base/acid catalysts plus a proposed method in the analysis of total fatty acids in lipid standards mixtures, foodstuff and biological samples. The addition of aprotic solvents to the reaction mixture to avoid alterations was also tested. Results confirmed that procedures solely involving acid catalyst resulted in incomplete derivatizations and alteration of the fatty acid profile, partially corrected by addition of the aprotic solvent. The proposed method combining sodium methoxyde and sulfuric acid showed absence of alteration of the FAME profile and the best values for response factors (short chain fatty acids to PUFA), accuracy in the determination of total cholesterol and derivatization performance, thus showing a high reliability in the determination of the total fatty acid composition in biological samples and foods.

Extraction and characterization of lipids from Sarcocornia ambigua meal: a halophyte biomass produced with shrimp farm effluent irrigation

Sarcocornia ambigua is a perennial glasswort, native of South America and a potential new seed-oil crop and forage for direct irrigation with salt water. Small seeds develop inside fertile segments of its cylindrical leafless shoots and, at the harvest, seeds are typically mixed with remnant cellulose material difficult to separate. This work evaluated different extraction methods and the composition of total esterified fatty acids in a meal of ground fertile shoots of S. ambigua, seeking for an alternative primary matter and larger yield of total lipids. The highest lipid yield was obtained with a chloroform:methanol mixture (2:1)(v/v) (5.2% of dry weight). The most abundant polyunsaturated fatty acids in the meal were linoleic acid (C18:2; 21.4%) and oleic acid (C18:1; 18.3%). Fifty six percent of the lipids in S. ambigua meal were saturated and palmitic acid (C16:0) was the main fraction (19.8%). Long-chain fatty acids (≥ C20) represented 29.5% of the lipids. Most abundant long-chain fatty acids were behenic acid (C22:0; 7.1%), lignoceric acid (C24:0; 5.3%) and montanic acid (C28:0; 4.0%). The percentage of saturated lipids in S. ambigua meal was higher than that of vegetable oils with a MUFA nutritional profile and some of these lipids have known bioactive properties.

The Establish of Four Kinds of Chinese Primary Economic Crab Species Fatty Acid Fingerprints

In order to establish our common economic crabs fatty acid fingerprints, the total lipid and phospholipid fatty acid composition of our common economic crabs were determined and analyzed by GC-MS. The results show that: the highest proportion of Eriocheir sinensis is monounsaturated fatty acid (MUFA), while the highest proportion of the other three crab is polyunsaturated fatty acid (PUFA). The percentage of EPA+DHA in Total fat of four kinds of crab is between 7.58%~36.82% .The ratio of EPA and DHA of three kinds of sea crab is higher than it in Eriocheir sinensis. Through the comparative analysis of the fatty acid composition of the total lipid and the phospholipids, we identified seven characteristic fat acids of the four species of crabs.They are C16:0, C18:1n-9, C18:2n-6, C18:3n-3, C20:5n-3, C22:6n-3,and PUFA(PL). Chemical information of four kinds of crabs in lipid composition can be mastered through fatty acids fingerprints of four kinds of crabs which used seven kinds of characteristic fatty acid as index.

The effect of alkanes on the physiology and metabolism of the entomopathogenic fungus, Isaria fumosorosea

The influence of different alkanes on spore morphology, glyoxlate pathway enzyme activities, total lipid contents and fatty acid composition of Isaria fumosorosea were investigated under laboratory conditions. Fungal spores grown on different alkanes showed higher germination and mycelial growth when compared to control. A strong induction of glyoxlate cycle enzymes in cell-free extracts was observed for cells grown on different alkanes when compared to glucose and control. Higher activities of glyoxlate cycle enzymes were observed for cells grown on alkanes when compared to other treatments. Even numbered fatty acids accounted for the majority of fatty acid production with a significant increase in relative amounts of linoleic acid and palmatic acid observed for conidia grown on alkanes. These results indicate that addition of alkanes to culture media can be a tool to pre-induce metabolic adaptations that can facilitate successful infection of insect host by entomopathogenic fungi.

Cerebrospinal fluid fatty acid composition changes in Alzheimer’s disease (651.7)

Objectives: To test the hypothesis that levels of saturated fatty acids (SAFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) that are structural components of neuronal membranes or are precursors of signaling molecules change in Alzheimer’s disease (AD).Methods: We recruited and collected cerebrospinal fluid (CSF) from cognitively healthy (CH), mild cognitively impairment (MCI), and AD study participants. After fractionation of CSF into a 200,000 g supernatant fluid (SF) and nanoparticle (NP) fractions, we used gas chromatography‐ negative ion chemical ionization/mass spectrometry to determine the total fatty acid composition of these fractions.Results: Levels of some SAFA, MUFA, and PUFA differed between the SF and NP fractions. Docosahexaenoic acid [DHA, (C22:6, n‐6)] levels were lower in AD compared with CH while alpha linoleic acid [α‐LNA, (C18:3, n‐3)] levels were lower in MCI compared with CH in the SF fraction. In the NP fraction, levels of SAFAs (C15:0, C16:0) and a MUFA (C15:1) differentiated CH from MCI while levels of MUFAs (C15:1, C19:1) and PUFAs (C20:2, C20:3, C22:4, C22:5) were altered in AD compared with CH.Conclusions: Fatty acid metabolism is compartmentalized in CSF fractions and differences between clinical groups suggest that energy metabolism or oxidative pathways are important in AD pathophysiology. Some fatty acids in CSF fractions may be biomarkers of AD. Thus, dietary or pharmacological approaches to regulate brain fatty acid levels and measurement of fatty acid in CSF fractions may be helpful in prevention or monitoring AD.Grant Funding Source: L.K. Whittier and the Helen Posthuma Foundations