Anti-Inflammatory and Anti-Platelet Properties of Lipid Bioactives from Apple Cider By-Products

The valorization of food industry by-products as sources of bioactive compounds is at the forefront of research in functional foods and nutraceuticals. This study focuses on bioactives of apple cider by-products (ACBPs) with putative cardio-protective properties. Total lipids (TLs) were extracted from ACBPs of apple varieties that are low (ACBP1), medium (ACBP2), and high (ACBP3) in tannins and were further separated into polar lipids (PLs) and neutral lipids (NLs). The functionality of these lipid extracts and of their HPLC-derived lipid fractions/PL subclasses were assessed in vitro against human platelet aggregation induced by the thrombotic and inflammatory platelet agonists platelet-activating factor (PAF) and adenosine diphosphate (ADP). The fatty acid profile of PLs and their most bioactive lipid fractions were evaluated by GC–MS analysis. The PL extracts exhibited higher specificity against the PAF-induced platelet aggregation compared to their anti-ADP effects, while TL and NL showed lower bioactivities in all ACBPs. HPLC analysis unveiled that the most bioactive PL from all ACBPs were those in PL fraction 3 containing phosphatidylcholines (PCs). PLs from all ACBPs and their PC bioactives were rich in polyunsaturated fatty acids (PUFAs) and especially in the essential omega-6 (n-6) linoleic acid (LA) and omega-3 (n-3) alpha linolenic acid (ALA), with favorably low values of the n-6/n-3 PUFA ratio, thus providing a rationale for their higher anti-inflammatory bioactivities. Within this study, highly bioactive PL compounds with strong anti-inflammatory and anti-platelet properties were identified in ACBPs, which can be potentially utilized for producing cardio-protective functional foods and/or nutraceuticals.     

Fatty acid and phytosterol contents of some Romanian wild and cultivated berry pomaces

The total oil content and composition of fatty acids and phytosterols of five Transylvanian (Romania) pomaces of wild and cultivated blueberries (Vaccinium myrtillus), wild cowberry (Vaccinium vitis-idaea) and raspberry (Rubus idaeus), and cultivated black chokeberry (Aronia melanocarpa), were determined by capillary gas chromatography. Out of the five pomace oils, the percentages of polyunsaturated fatty acids (PUFAs) ranged from 37 % to 69 %. The lipid classes analysed (PLs ?? polar lipids, TGs ?? triacylglycerols, SEs ?? sterol esters) were separated and identified using thin-layer chromatography. TGs showed the highest PUFAs content (ranging from 41.9 % to 72.5 %) and PUFAs/SFAs (saturated fatty acids) ratios (in the range of 5.8?C33.1 %). In the case of PL and SE fractions, the levels of SFA were significantly higher than in TGs. The total amount of sterols was in the range of 101.6?C168.2 mg per 100 g of lipids of the pomaces analysed. The predominant phytosterols were ??-sitosterol, stigmastanol + isofucosterol, and campesterol. The results indicated that the investigated pomace oils, due to their good balance between n-6 and n-3 fatty acids (except for chokeberry) and high ??-sitosterol content, could be excellent sources of PUFAs and phytosterols, thus suggesting potential value-added utilisation of berry waste oils for preparing functional foods or food supplements.     

In vivo and in vitro lipid peroxidation of arachidonate esters: the effect of fish oil omega-3 lipids on product distribution

The effect of lipid composition on the distribution of free radical oxidation products derived from arachidonic acid (20:4) esters has been studied in vitro and in vivo. Pro-inflammatory prostaglandin (PG) F2-like compounds, termed F2-isoprostanes (IsoPs), are produced in vivo and in vitro by the free radical-catalyzed peroxidation of arachidonic acid. Controlled free radical oxidation of mixtures of fatty acid esters in vitro showed that the formation of IsoPs from arachidonate is dramatically influenced by the presence of other fatty acid esters in the reaction mixture. Thus, three lipid mixtures containing the same arachidonate concentration but different amounts of other fatty esters (16:0; 18:1; 18:2; 20:5, and 22:6) were oxidized, and the product yields were determined by GC and LC/MS/MS analysis. The yield of F2-IsoP formed after 1 h of oxidation was 18% (based on arachidonate consumed) for mixtures containing arachidonate as the only oxidizable PUFA, but yields of these biologically active compounds dropped to 6% in polyunsaturated fatty acid (PUFA) mixtures typical of those found in tissues of fish oil-fed animals. F2-IsoP levels were also monitored in the livers of mice on diets supplemented with eicosapentaenoic acid (C20:5 omega-3; EPA), the PUFA most abundant in fish oil. While the level of arachidonic acid present in livers was not significantly different from that in control animals, levels of IsoPs in the liver were reduced in the EPA-fed mice compared to those in controls under conditions of oxidative stress (60 +/- 25% reduction, n = 5) or at baseline (48 +/- 14% reduction, n = 5). These results suggest that dietary omega-3 PUFAs may influence the formation of bio-active peroxidation products derived from omega-6 PUFAs by channeling the free radical pathway away from the F2-IsoPs.     

Determination of fatty acids in fish oil dietary supplements by capillary chromatography with laser-induced fluorescence detection.

The 4-bromomethyl-7-methoxycoumarin derivatives of 14 saturated and unsaturated fatty acids, including the omega-3 fatty acids, were separated by reversed-phase liquid chromatography and detected by laser-induced fluorescence. Baseline resolution was obtained by using a high-efficiency packed capillary column with 240,000 theoretical plates, together with a systematic optimization of the mobile phase composition. The retention indices of the fatty acid derivatives correlated well with a predictive empirical model, showing accuracy better than 0.46% relative error and reproducibility better than +/- 0.1% relative standard deviation. The physiologically important fatty acids with 12-22 carbon atoms and 0-6 double bonds were determined at the femtomole level in fish oil dietary supplements by using this methodology.     

Fatty-acid composition of rat brain lipids. Determined by support-coated open-tubular gas chromatography.

The nonhydroxy fatty acid composition of rat brain lipids (except gangliosides) was determined by support-coated open-tubular (SCOT) gas chromatography. Fatty acids of both odd and even chain lengths ranging from C14 to C26 were detected. Brain lipids contained 49% saturated, 29% monounsaturated, and 22% polyunsaturated fatty acids. Monoenoic fatty acids were mainly of the omega-9 and omega-7 series with minor amounts of omega-10 and amega-11 isomers. Dienes and trienes consisted of omega-6, amega-7, and omega-9 series. Tetraenes were of the omega-6 series. Small amounts of omega-6 and omega-3 pentaenes were detected. The most abundant polyunsaturated fatty acid was 22:6omega-3. The advantages of support-coated open-tubular columns over wall-coated open-tubular columns for the analysis of brain lipid fatty acids are discussed.     

Chemical Composition,In Vitro Bioaccessibility and Antioxidant Activity of Polyphenolic Compounds from Nutraceutical Fennel Waste Extract

Fennel (Foeniculum vulgare Mill.) waste contains a broad range of bioactive molecules, including polyphenols, which have poor bioaccessibility during gastrointestinal digestion. This work aimed to investigate the bioaccessibility of total phenolic compounds and the antioxidant capacity during simulated gastrointestinal digestion using two nutraceutical formulations based on non-acid-resistant (NAR) and acid-resistant (AR) capsules containing aqueous-based extracts from fennel waste. Moreover, to obtain a comprehensive investigation of the polyphenolic constituents of the fennel waste extract, a high-resolution mass spectrometry (Q-Orbitrap) analysis was performed. Notably, chlorogenic acids, such as 4-caffeoylquinic acid and 3,4-dicaffeoylquinic acid, were the most detected compounds found in assayed samples (1.949 and 0.490 mg/g, respectively). After in vitro gastrointestinal digestion, the extract contained in AR capsules displayed higher bioaccessibility in both the duodenal and colonic stages (1.96 and 5.19 mg GAE/g, respectively) than NAR capsules (1.72 and 3.50 mg GAE/g, respectively), suggesting that the acidic gastric conditions negatively affected the polyphenol compounds released from the NAR capsules. Therefore, the aqueous extract of fennel waste could be proposed as an innovative and easily available source of dietary polyphenols. Furthermore, the use of an AR capsule could improve the polyphenol bioaccessibility and can be proposed as a nutraceutical formulation.     

Biosynthetic production of universally <Superscript>13</Superscript>C-labelled polyunsaturated fatty acids as reference materials for natural health product research

Long-chain polyunsaturated fatty acids (LCPUFA) including eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) have become important natural health products with numerous proven benefits related to brain function and cardiovascular health. Not only are omega-3 fatty acids available in a plethora of dietary supplements, but they are also increasingly being incorporated as triglycerides into conventional foods, including bread, milk, yoghurt and confectionaries. Recently, transgenic oil seed crops and livestock have been developed that enhance omega-3 fatty acid content. This diverse array of matrices presents a difficult analytical challenge and is compounded further by samples generated through clinical research. Stable isotope ¹³C-labelled LCPUFA standards offer many advantages as research tools because they may be distinguished from their naturally abundant counterparts by mass spectrometry and directly incorporated as internal standards into analytical procedures. Further, ¹³C-labelled LCPUFAs are safe to use as metabolic tracers to study uptake and metabolism in humans. Currently, ¹³C-labelled LCPUFAs are expensive, available in limited supply and not in triglyceride form. To resolve these issues, marine heterotrophic microorganisms are being isolated and screened for LCPUFA production with a view to the efficient biosynthetic production of U-¹³C-labelled fatty acids using U-¹³C glucose as a carbon source. Of 37 isolates obtained, most were thraustochytrids, and either DHA or omega-6 docosapentaenoic acid (22:5n-6) were produced as the major LCPUFA. The marine protist Hyalochlorella marina was identified as a novel source of EPA and omega-3 docosapentaenoic acid (22:5n-3). As proof of principle, gram-level production of ¹³C-labelled DHA has been achieved with high chemical purity ( >99%) and high ¹³C incorporation levels (>90%), as confirmed by NMR and MS analyses. Finally, U-¹³C-DHA was enzymatically re-esterified to glycerol to yield a ¹³C-labelled tridocosahexaenoin.     

An Analysis of Oxidative Changes and the Fatty Acid Profile in Stored Poultry Sausages with Liquid and Microencapsulated Fish Oil Additives

This study deals with the fatty acid profile and oxidative changes (TBARS) in vacuum-packed (VP) or modified-atmosphere-packed (MAP) finely-comminuted poultry sausages with liquid fish oil and microencapsulated fish oil (MC) additives. An analysis of omega-3 fatty acids (EPA and DHA) showed that their content in the samples with the fish oil additive decreased from the initial value of 0.22 g∙100 g⁻¹ of the product to 0.18 g∙100 g⁻¹ (MAP) and 0.17 g∙100 g⁻¹ (VP), respectively. After in vitro digestion, the total EPA and DHA content in the sample with microencapsulated oil amounted to 0.17 g∙100 g⁻¹ of the product. The TBARS values showed the VP samples with both forms of the fish oil additive had the lowest values on the first day of storage. Storage of the samples for 21 days caused a slight increase in the degree of lipid oxidation. The research indicated that the forms of the oil additive did not have a negative influence on the sensory features or the physicochemical properties of the sausages. The EPA and DHA levels in samples with liquid fish oil and those with oil microcapsules were sufficient for the sausage producer to declare high content of these fatty acids in accordance with the current EC regulation.     

Low n-6/n-3 Gestation and Lactation Diets Influence Early Performance,Muscle and Adipose Polyunsaturated Fatty Acid Content and Deposition,and Relative Abundance of Proteins in Suckling Piglets

Elevated omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) ratios in swine diets can potentially impose a higher risk of inflammatory and metabolic diseases in swine. A low ratio between the two omega PUFAs has beneficial effects on sows’ and piglets’ production performance and immunity status. At present, there are few studies on how sow nutrition directly affects the protein and fat deposition in suckling piglets. Two groups of sows were fed diets with high or low n-6/n-3 polyunsaturated ratios of 13:1 (SOY) and 4:1 (LIN), respectively, during gestation and lactation. Longissimus dorsi muscle and adipose tissue from newborn piglets, nourished only with sow’s milk, were subjected to fatty acid profiling by gas chromatography–mass spectrometry (GC-MS) and to proteomics assays based on nano-liquid chromatography coupled to high-resolution tandem mass spectrometry (nLC-HRMS). Fatty acid profiles on both muscle and adipose tissues resembled the magnitude of the differences between fatty acid across diets. Proteomic analysis revealed overabundance of 4 muscle and 11 adipose tissue proteins in SOY compared to LIN in both piglet tissues. The detected overabundance of haptoglobin, an acute-phase protein, and the stimulation of protein-coding genes and proteins related to the innate immune response and acute inflammatory response could be associated with the pro-inflammatory role of n-6 PUFAs.     

Development of botanical and fish oil standard reference materials for fatty acids

As part of a collaboration with the National Institutes of Health’s Office of Dietary Supplements and the Food and Drug Administration’s Center for Drug Evaluation and Research, the National Institute of Standards and Technology has developed Standard Reference Material (SRM) 3274 Botanical Oils Containing Omega-3 and Omega-6 Fatty Acids and SRM 3275 Omega-3 and Omega-6 Fatty Acids in Fish Oil. SRM 3274 consists of one ampoule of each of four seed oils (3274-1 Borage (Borago officinalis), 3274-2 Evening Primrose (Oenothera biennis), 3274-3 Flax (Linium usitatissimum), and 3274-4 Perilla (Perilla frutescens)), and SRM 3275 consists of two ampoules of each of three fish oils (3275-1 a concentrate high in docosahexaenoic acid, 3275-2 an anchovy oil high in docosahexaenoic acid and eicosapentaenoic acid, and 3275-3 a concentrate containing 60 % long-chain omega-3 fatty acids). Each oil has certified and reference mass fraction values for up to 20 fatty acids. The fatty acid mass fraction values are based on results from analyses using gas chromatography with flame ionization detection (GC-FID) and mass spectrometry (GC/MS). These SRMs will complement other reference materials currently available with mass fractions for similar analytes and are part of a series of SRMs being developed for dietary supplements.

An investigation of frequently consumed edible oils in Turkey in terms of omega fatty acids

The fatty acid profiles of frequently consumed oils and crops cultivated in Turkey were investigated in regard to omega fatty acids. Analyses were carried out on commercially sold oils, sunflower, olive, and fish oils, and oils extracted from fatty seeds of hazelnut, walnut, olive, sunflower, poppy, sesame, and pumpkin, and butter produced in Turkey. Hazelnut and olive oils were found to be rich in omega-9 (oleic acid 18:1), walnut, poppy seed, sesame, and pumpkin seed were rich in omega-6 (linoleic acid 18:2), and butter was rich in short chain fatty acids and omega-9. Fish oil, from mackerel, was the richest in omega-3 fatty acids and fatty acid diversity. There were some alterations between commercially sold oils and oils extracted from seeds in regard to fatty acid percentages and variety.     

INFLUENCE OF DIETARY OMEGA-6, -3 FATTY ACID SOURCES ON THE INITIATION AND PROMOTION STAGES OF PHOTOCARCINOGENESIS

To determine the segment along the carcinogenic continuum at which dietary lipid exerts its principal effect, six groups of 35 Skh-HR-1 hairless mice were placed on defined isocaloric diets containing either 0.75%, 12% corn oil or 12% menhaden oil as sources of omega-6 or omega-3 fatty acids, respectively. All animals received an 11 week course of UV-radiation from fluorescent sunlamps. Upon termination of UV, diets of some groups were crossed-over to either low fat, high fat, omega-6 or omega-3 fatty acid sources. The first tumor appeared at week 14. Life-table analysis of the tumor incidence curves and Wilcoxon tests of tumor multiplicity provided evidence that high corn oil diets significantly (P < 0.01) enhance carcinogenic expression; that tumor enhancement by the omega-6 fatty acid source occurs during the post-initiation, or promotion, stage; that replacement with a low corn oil diet after UV-initiation will negate the exacerbating effect of high corn oil; and that an omega-3 fatty acid source inhibits UV-carcinogenesis even at high dietary levels, although not during the post-initiation stage.     

Sterol oxidation in meat- and fish-based homogenized baby foods containing vegetable oils

Sterol oxidation was evaluated in commercial meat- and fish-based homogenized baby foods containing vegetable oil. Gas chromatography coupled with mass spectrometry (GC/MS) was used for the analytical determination of 7-ketocholesterol and 7-ketositosterol, which were chosen as markers of sterol oxidation in lipids of animal origin and vegetable origin, respectively. Cholestanetriol was also quantified, because its negative effects on atherogenesis and other biological processes are well known. In meat-based samples, the levels of 7-ketocholesterol and 7-ketositosterol were 22-89 and 11-40 microg/serving, respectively, whereas the cholestanetriol levels were 7-38 microg/serving. The 7-ketocholesterol/cholesterol percent ratio was characteristic of each kind of meat and related to the levels of unsaturated fatty acids of animal lipids. In fish-based samples, the cholestanetriol and 7-ketocholesterol levels per serving were significantly lower than in meat samples, but in fish fillets they were about 20-25%, instead of 40%, of the ingredients. The values of the 7-ketocholesterol/cholesterol percent ratio in fish-based products were close to the values computed for chicken or turkey-based products. The detected values of cholestanetriol showed that the addition of vegetable oil enhances the development of the indirect bimolecular pathway of cholesterol oxidation, which was even more favorable in fish-based products.     

Analysis of esterified and nonesterified fatty acids in serum from obese individuals after intake of breakfasts prepared with oils heated at frying temperature

In this study, levels of esterified and nonesterified fatty acids (EFAs and NEFAs, respectively) were compared in obese individuals (body mass index between 30 and 47 kg m^–2) in basal state and after intake of four different breakfasts prepared with oils heated at frying temperature. The target oils were three sunflower oils—pure, enriched with dimethylsiloxane (400 μg mL^–1) as lipophilic oxidation inhibitor, and enriched with phenolic compounds (400 μg mL^–1) as hydrophilic oxidation inhibitors—and virgin olive oil with a natural content of phenolic compounds of 400 μg mL^–1. The intake of breakfasts was randomized to avoid trends associated to this variability source. EFAs and NEFAs were subjected to a sequential derivatization step for independent gas chromatography–mass spectrometry analysis of both fractions of metabolites in human serum. Derivatization was assisted by ultrasonic energy to accelerate the reaction kinetics, as required for high-throughput analysis. Statistical analysis supported on univariate (multifactor ANOVA) and multivariate approaches (principal component analysis and partial least squares–discriminant analysis) allowed identification of the main variability sources and also discriminating between individuals after intake of each breakfast. Individuals’ samples after intake of breakfasts prepared with virgin olive oil were clearly separated from those who ingested the remaining breakfasts. The main compounds contributing to discrimination were omega-3 and omega-6 EFAs with special emphasis on arachidonic acid and eicosapentaenoic acid. These two polyunsaturated fatty acids are the precursors of eicosanoid metabolites, which are of vital importance as they play important roles in inflammation and in the pathogenesis of vascular and malignant diseases as cancer.     

The Effects of Food on Cannabidiol Bioaccessibility

Cannabidiol (CBD) is a hydrophobic non-psychoactive compound with therapeutic characteristics. Animal and human studies have shown its poor oral bioavailability in vivo, and the impact of consuming lipid-soluble CBD with and without food on gut bioaccessibility has not been explored. The purpose of this research was to study the bioaccessibility of CBD after a three-phase upper digestion experiment with and without food, and to test lipase activity with different substrate concentrations. Our results showed that lipase enzyme activity and fatty acid absorption increased in the presence of bile salts, which may also contribute to an increase in CBD bioaccessibility. The food matrix used was a mixture of olive oil and baby food. Overall, the fed-state digestion revealed significantly higher micellarization efficiency for CBD (14.15 ± 0.6% for 10 mg and 22.67 ± 2.1% for 100 mg CBD ingested) than the fasted state digestion of CBD (0.65 ± 0.7% for 10 mg and 0.14 ± 0.1% for 100 mg CBD ingested). The increase in bioaccessibility of CBD with food could be explained by the fact that micelle formation from hydrolyzed lipids aid in bioaccessibility of hydrophobic molecules. In conclusion, the bioaccessibility of CBD depends on the food matrix and the presence of lipase and bile salts.     

Identification by gas chromatography and mass spectrometry of lipids from the rat Harderian gland

Lipids from rat Harderian glands were extracted with ethyl acetate, hydrolysed with base and examined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) as trimethylsilyl (TMS), [2H9]TMS, methyl ester-TMS, picolinyl, nicotinate and nicotinylidene derivatives. The latter three derivatives were used to reveal the structures of the alkyl chains of fatty acids, alcohols and glycerol ethers, respectively. Forty-eight compounds were identified, representing about 97% of the total extracted lipids as measured by GC peak areas. The major constituents were fatty acids with chain lengths from 12 to 22 carbon atoms (mainly C18 and C20) and fatty alcohols (C16 to C26) derived from wax esters. Most of these acids and alcohols were unsaturated in the omega-7 position and were accompanied by smaller amounts of the saturated and omega-5 monounsaturated analogues. glycerol ethers were also identified for the first time in this secretion; the ether chains contained from 14 to 19 carbon atoms (mainly 16) and were straight-chain saturated, unsaturated (omega-5 and omega-7) and branched (iso). The only sterol found was cholesterol amounting to 1.24% of the total extract.     

Synergistic Action of Membrane-Bound and Water-Soluble Antioxidants in Neuroprotection

Prevention of neurodegeneration during aging, and support of optimal brain function throughout the lifespan, requires protection of membrane structure and function. We review the synergistic action of different classes of dietary micronutrients, as well as further synergistic contributions from exercise and stress reduction, in supporting membrane structure and function. We address membrane-associated inflammation involving reactive oxygen species (ROS) that produce immune regulators from polyunsaturated fatty acids (PUFAs) of membrane phospholipids. The potential of dietary micronutrients to maintain membrane fluidity and prevent chronic inflammation is examined with a focus on synergistically acting membrane-soluble components (zeaxanthin, lutein, vitamin E, and omega-3 PUFAs) and water-soluble components (vitamin C and various phenolics). These different classes of micronutrients apparently operate in a series of intertwined oxidation-reduction cycles to protect membrane function and prevent chronic inflammation. At this time, it appears that combinations of a balanced diet with regular moderate exercise and stress-reduction practices are particularly beneficial. Effective whole-food-based diets include the Mediterranean and the MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay diet, where DASH stands for Dietary Approaches to Stop Hypertension).     

Dietary,but not topical,alpha-linolenic acid suppresses UVB-induced skin injury in hairless mice when compared with linoleic acids

Peroxidizability of fatty acids in the air is roughly proportional to the number of double bonds, but in vivo peroxidation proceeds in a more complex manner. Here, we compared the effects of dietary and topically applied oils enriched with linoleic acid (LA, 18:2n-6) or alpha-linolenic acid (ALA, 18:3n-3) on UV-induced skin injury in a strain of hairless mice. The UVB-induced erythema score was significantly lower in mice with topically applied creams containing LA and ALA than in mice with the basal cream; no significant increase in the score was detected in the ALA group compared with the LA group. However, dietary ALA inhibited the increase in erythema score after UVB irradiation compared with LA. The peroxidizability index of the skin total lipids was significantly higher, but UVB-induced prostaglandin E2 (PGE2) production was significantly lower in the group fed an ALA-rich diet compared with the group fed an LA-rich diet. The levels of thiobarbituric acid-reactive substances, estimated in the presence of butylated hydroxytoluene in the assay mixture, were not affected by UVB treatment or by the dietary fatty acids, but the severity of the skin lesion was associated with PGE2 levels. These results indicate that the type of fatty acids, n-6 or n-3, is critical for the suppression of UVB-induced skin lesion when the skin fatty acids are modified by dietary manipulation. Anti-inflammatory activity of dietary flaxseed oil with relatively high ALA and low LA contents was demonstrated in UVB-irradiated hairless mice.     

Isolation of 6,9,12,15-Hexadecatetraenoic Fatty Acid (16:4n-1) Methyl Ester from Transesterified Fish Oil by HSCCC

Fish oil is considered a healthy food due to the presence of large amounts of polyunsaturated fatty acids (PUFAs), especially in the form of n-3 fatty acids 5,8,11,14,17-eicosapentaenoic acid (20:5n-3; EPA) and 4,7,10,13,16,19-docosahexaenoic acid (22:6n-3; DHA). However, fish oil is known to contain many other PUFAs, some of which are uncommon and whose bioactivity is scarcely investigated. In this study, we isolated the rare PUFA 6,9,12,15-hexadecatetraenoic fatty acid (16:4n-1) which bears a double bond on the terminal carbon from fish oil in form of its methyl ester. We used high-speed counter-current chromatography (HSCCC) for the fractionation of 500 mg-portions of fatty acid methyl esters prepared from a fish oil capsule and investigated the fractions by GC/MS. Twenty-eight 13-mL fractions were collected and fatty acid methyl esters were detected in fractions 11–23. The elution was carried out in normal phase mode, providing the long-chained saturated and monoenoic fatty acids first. More than 100 fatty acids ranging from 10:0 to 26:0 could be identified in the HSCCC fractions, and most of them were polyunsaturated. The reproducibility of the HSCCC method was shown by repeated injection of the fish oil and the fractions containing 6,9,12,15-hexadecatetraenoic fatty acid (16:4n-1). The late eluting 16:4n-1 methyl ester was isolated in pure form and its structure was verified.

     

3种前处理方法处理婴幼儿配方奶粉中二十二碳六烯酸、花生四烯酸、亚油酸和α-亚麻酸的差异性

探讨了国家标准GB 5009.168-2016中乙酰氯-甲醇甲酯化法、酸水解酯化法和碱水解酯化法3种前处理手段处理婴幼儿配方奶粉中4种多不饱和脂肪酸(二十二碳六烯酸、花生四烯酸、亚油酸和α-亚麻酸)含量的差异性。乙酰氯-甲醇甲酯化法和酸水解酯化法明显优于碱水解酯化法。乙酰氯-甲醇甲酯化法中,样品的水解和脂肪的甲酯化同时进行并相互促进,使得脂肪的释放和甲酯化能够完全进行。通过对反应过程和添加回收率两个方面的考察,证明了乙酰氯-甲醇甲酯化法检测结果的准确性。酸、碱水解酯化法是分别利用酸、碱对样品进行水解,然后提取脂肪进行甲酯化。从水解效率、提取效率及甲酯化效率3个方面对酸、碱水解酯化法进行对比,结果表明,水解效率是影响酸、碱水解差异性的主要因素,酸水解法更适用于婴幼儿配方奶粉中不饱和脂肪酸的测定。通过对实际样品的检测,进一步验证了乙酰氯-甲醇甲酯化法和酸水解酯化法测定多不饱和脂肪酸的准确性,同时对其他食品中脂肪酸的测定具有较强的指导意义。