Triacylglycerol Molecular Species Research Articles

Comparative analysis of DHA positional distribution and triacylglycerol molecular species in algal oil (Schizochytrium sp.) from different oil processing

This study aims to analysis the content and positional distribution of docosahexaenoic acid (DHA, 22:6 n-3) in algal oils (Schizochytrium sp.) using both Candida antarctica Lipase B (CAL-B)-catalyzed-transesterification combined with GC and 13C NMR. The triacylglycerol (TAG) molecular species in algal oils were also identified and quantified using LC-MS. The algal oils were from 3 kinds of oil processing including crude oil (CAO), liquid phase and solid phase oils from fractionation (LAO and SAO) as well as re-esterified triacylglycerol (rTAG). Algal oils contain 55%–97% polyunsaturated fatty acids (PUFAs) and 45%–80% DHA of the total oil; and DHA dominantly esterified at sn-2 position of glycerol backbone with the ratio of sn-2 DHA to total DHA ranged from 32% to 48%. A total of 42 TAGs were identified including 27 TAGs contained DHA, of which the 22:6/22:6/22:5 and 22:6/22:6/22:6 were the predominant species. The lipids containing DHA of algal oils are influenced by the fractionation processing. Compared with physical modified algal oils, rTAG has high DHA content (∼80%, P < 0.05) but lower sn-2 DHA relative content (∼32%, P < 0.05). This study provides an effective analysis scheme for high-PUFA-oils which will be used to develop novel functional oils.

Shotgun-Based Mass Spectrometry Analysis of Phospholipid and Triacylglycerol Molecular Species and Eicosanoids in Salmon Muscle Tissue on Feeding Microbial Oil.

The continuous growth of aquaculture places a growing demand on alternative sources of fish oil (FO). Certain microorganisms provide a sustainable replacement for FO due to their content of EPA and DHA, which are essential for fish health. Appreciable evidence shows that changes in feeding sources may alter the nutritional components of salmon; however, the influence of diets on lipid species remains unclear. In this study, the identification and semi-quantification of lipid molecular species in salmon muscle during feeding with a microbial oil (MO) were carried out by focusing on triacylglycerol (TAG) and diacyl-phospholipid using shotgun-based mass spectrometry analysis. DHA in the MO diet was efficiently incorporated into phospholipid structures on feeding, followed by accumulation in salmon muscle. The MO diet elevated the level of certain EPA-containing TAGs, such as TAG C52:5 (16:0_16:0_20:5) and TAG C54:6 (16:0_18:1_20:5), indicating that the MO diet may be an excellent source for enhancement of the abundance of ω3 lipids. Further, prostaglandins (PGs) PGE2 and PGF3α were identified and quantified for the first time in salmonid tissue.

Multi-Dimensional Liquid Chromatography of Pulse Triacylglycerols with Triple Parallel Mass Spectrometry

We analyzed ten pulses (the dried seeds of legumes), i.e., baby lima beans, black beans, black-eyed peas, butter beans, cranberry beans, garbanzo beans, green split peas, lentils, navy beans, and pinto beans, using three-dimensional liquid chromatography (3D-LC) with parallel second dimensions, LC × (LC + LC). We combined non-aqueous reversed-phase (NARP) chromatography as the first dimension separation, 1D, with argentation UHPLC for separation based on degree and location of unsaturation in the first second dimension, 2D(1), and multi-cycle NARP-UHPLC in the second second dimension, 2D(2). Pulses contained 1.9% to 2.7% lipids, except garbanzo beans, which contained 6.2% lipids. High-resolution, accurate-mass (HRAM) orbitrap mass spectrometry (MS) was used to perform lipidomic analysis of the 2D(2) and percent relative quantification, showing that the most abundant average triacylglycerol (TAG) molecular species across all pulses were PLL at 10.67% and PLLn at 10.45%. Common beans (Phaseolus vulgaris) were clustered together using principal component analysis (PCA), showing the highest levels of linolenic acid, C18:3, in molecular species such as PLnLn, LLnLn, and OLLn, with palmitic (P), C16:0, linoleic (L), 18:2, linolenic (Ln), 18:3, and oleic (O), 18:1, FAs. Calibration curves derived from interweaved sets of regioisomer standards allowed the absolute quantification of 1,2- and 1,3-regioisomers for a subset of TAGs.

Effects of lipids from multiple sources on glyceride composition, concentration, and structure of infant formulas benchmarked to human milk

The important parameters affecting the nutritional properties of lipids were analyzed and compared between human milk (HM), infant formulas (IFs), mammalian milk, and substitute fat, including molecular species, fatty acid composition, glyceride content, and important structural triacylglycerols (TAGs). The molecular species of triacylglycerols with functional fatty acids were significantly different between HM and IFs, and their contents in HM were significantly higher than those in IFs. Accordingly, the evaluation scores of fatty acid composition and glyceride content in IFs were less than 50 compared to HM. Although the introduction of vegetable oils effectively improved the unsaturation of IF lipid, the excessive addition of TAGs rich in oleic and linoleic acid resulted in an imbalance of TAG composition and structure. Only 36.84 % of IFs were supplemented with structured lipids, but those still lacked sn-2 palmitate TAGs. The adoption of multiple lipids and novel processing technologies is required for novel IFs to match the composition, content, positional structure and spherical membrane structure of HM as closely as possible.

Triacylglycerols are a Rich Source of Polyunsaturated Fatty Acids in Red King Crab Juveniles (Paralithodes camtschaticus)

Abstract: In the Sea of Japan and the Okhotsk Sea, the red king crab Paralithodes camtschaticus is the major commercial species of the crab. The crab is a rich source of polyunsaturated fatty acids (PUFAs). The composition of triacylglycerol (TG) molecular species in freshly collected juveniles of P. camtschaticus has been determined for the first time. By supercritical fluid chromatography with mass-spectrometry, 45 molecular species of TG were identified. Most of the molecular species contained docosahexaenoic acid (DHA; 22:6n-3), eicosapentaenoic acid (EPA; 20:5n-3), arachidonic acid (AA, 20:4n-6), and monounsaturated fatty acid 18:1. Thus, DHA, EPA, and AA received from the diet are used to build phospholipids (PL) and also stored in TG in P. camtschaticus juveniles. Therefore, the crab is a rich source of PUFAs, which are concentrated both in structural PL and in reserve TG.

Dynamics of Storage Lipids during the Recovery of Partially Bleached Coral &lt;i&gt;Sinularia heterospiculata&lt;/i&gt;

Global warming is causing the loss of coral symbionts and their bleaching. Researches of coral recovery are very important for the conservation of coral reefs. The lipidomic approach can provide detailed information about the processes that take place in the coral during bleaching and recovery. Using supercritical fluid chromatography in combination with mass-spectrometry, the dynamics of the main classes of storage lipids triacylglycerols (TG) and monoalkyldiacylglycerols (MADAG) during the recovery of the octocoral Sinularia heterospiculata after heat stress (32°C). It was shown that MADAG plays an important role in the energy balance of S. heterospiculata after heat stress. Under stress, the coral S. heterospiculata primarily consumed saturated MADAG molecular species. Changes in the profile of TG molecular species occurred only on the 16th day of the experiment. Probable, the stressed octocoral S. heterospiculata changes its energy strategy during recovery; therefore, the qualitative composition of reserve lipids is rearranged during the recovery period.

Lipidomics of coconut, almond and soybean milks - Comprehensive characterization of triacylglycerol class and comparison with bovine milk

Nowadays, plant-based milk consumption, as part of a healthy diet, is continuously increasing. In this paper, for the first time a lipidomic analysis on molecular species of triacylglycerol (TG) fraction of plant-based beverages (almond, soy, coconut) was performed by liquid chromatography quadrupole time-of-flight mass spectrometry. A total of 557 TG molecular species was measured, showing significantly different profiles between milk alternatives, compared with bovine milk. The most abundant TG molecular species were TG 18:1_18:1_18:1 and 18:1_18:1_18:2 for almond, TG 18:2_18:2_18:2 and 16:0_18:2_18:2 for soy, TG 12:0_10:0_12:0 and 12:0_12:0_14:0 for coconut. Unconventional fatty acids were detected in almond and soy. The main TG with ethereal linkage were TG-O 56:2, TG-O 56:4, and TG-O 56:5, while the main oxygenated TG was TG 54:5;1O. A total of 30 molecular species were identified as biomarkers for milk differentiation by principal component analysis, providing an interesting support for milk authentication and detection of adulteration on a larger sampling.

Human Milk Composition and Nutritional Status of Omnivore Human Milk Donors Compared with Vegetarian/Vegan Lactating Mothers.

Women of childbearing age in Western societies are increasingly adopting vegetarian diets. These women are sometimes rejected as milk donors, but little about the composition of their milk is known. The present study aimed to compare the intake, nutritional status, and nutritional composition of human milk from omnivore human milk donors (Donors) and vegetarian/vegan lactating mothers (Veg). Milk, blood, and urine samples from 92 Donors and 20 Veg were used to determine their fatty acid profiles, as well as vitamins and minerals. In a representative sample of both groups, we also determined the lipid class profile as a distribution of neutral and polar lipids, the molecular species of triacylglycerols, and the relative composition of phospholipids in their milk. A dietary assessment was conducted with a five-day dietary record (while considering the intake of supplements). We highlight the following results, expressed as the mean (SE), for the Veg vs. Donors: (1) Their docosahexaenoic acid (DHA) intake was 0.11 (0.03) vs. 0.38 (0.03) g/day; the plasma DHA was 0.37 (0.07) vs. 0.83 (0.06)%; and the milk DHA was 0.15 (0.04) vs. 0.33 (0.02)%. (2) Their milk B12 levels were 545.69 (20.49) vs. 482.89 (4.11) pM; 85% of the Veg reported taking B12 supplements (mean dose: 312.1 mcg/day); and the Veg group showed no differences with Donors in terms of total daily intake or plasma B12. (3) Their milk phosphatidylcholine levels were 26.88 (0.67) vs. 30.55 (1.10)%. (4) Their milk iodine levels were 126.42 (13.37) vs. 159.22 (5.13) mcg/L. In conclusion, the Vegs' milk was shown to be different from the Donors' milk, mainly due to its low DHA content, which is concerning. However, raising awareness and ensuring proper supplementation could bridge this gap, as has already been achieved for cobalamin.

Lipidome analysis and characterization of Buglossoides arvensis acyltransferases that incorporate polyunsaturated fatty acids into triacylglycerols

Buglossoides arvensis is a burgeoning oilseed crop that contains an unique combination of ω-3 and ω-6 polyunsaturated fatty acids (PUFA), constituting ~80–85% of seed triacylglycerols (TAGs). To uncover the critical TAG biosynthetic pathways contributing for high PUFA accumulation, we performed lipidome of developing seeds and characterized acyltransferases involved in the final step of TAG biosynthesis. During seed development, distribution of lipid molecular species in individual lipid classes showed distinct patterns from an early-stage (6 days after flowering (DAF)) to the middle-stage (12 and 18 DAF) of oil biosynthesis. PUFA-containing TAG species drastically increased from 6 to 12 DAF. The expression profiles of key triacylglycerol biosynthesis genes and patterns of phosphatidylcholine, diacylglycerol and triacylglycerol molecular species during seed development were used to predict the contribution of diacylglycerol acyltransferases (DGAT1 and DGAT2) and phospholipid: diacylglycerol acyltransferases (PDAT1 and PDAT2) to PUFA-rich TAG biosynthesis. Our analysis suggests that DGATs play a crucial role in enriching TAGs with PUFA compared to PDATs. This was further confirmed by fatty acid feeding studies in yeast expressing acyltransferases. BaDGAT2 preferentially incorporated high amounts of PUFAs into TAG, compared to BaDGAT1. Our results provide insight into the molecular mechanisms of TAG accumulation in this plant and identify target genes for transgenic production of SDA in traditional oilseed crops.

Elucidation of Olive Oil Oxidation Mechanisms by Analysis of Triacylglycerol Hydroperoxide Isomers Using LC-MS/MS.

Despite the importance of the insight about the oxidation mechanisms (i.e., radical and singlet oxygen (1O2) oxidation) in extra virgin olive oil (EVOO), the elucidation has been difficult due to its various triacylglycerol molecular species and complex matrix. This study tried to evaluate the mechanisms responsible for EVOO oxidation in our daily use by quantitative determination of triacylglycerol hydroperoxide (TGOOH) isomers using LC-MS/MS. The standards of dioleoyl-(hydroperoxy octadecadienoyl)-triacylglycerol and dioleoyl-(hydroperoxy octadecamonoenoyl)-triacylglycerol, which are the predominant TGOOHs contained in EVOO, were prepared. Subsequently, fresh, thermal-, and photo-oxidized EVOO were analyzed. The obtained results mostly agreed with the previously reported characteristics of the radical and 1O2 oxidation of linoleic acid and oleic acid. This suggests that the methods described in this paper should be valuable in understanding how different factors that determine the quality of EVOO (e.g., olive species, cultivation area, cultivation timing, and extraction methods) contribute to its oxidative stability.

Changes in Triacylglycerols Content and Quality Control Implications of Coix Seeds during Processing and Storage.

Coix seed is a kind of widespread cereal, and it is used as a folk medicine in China. The present work focuses on the analysis of changes in triacylglycerols (TAGs) content and mycotoxins of coix seed during the processing and storage period for its quality control. Using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS) and high-performance liquid chromatography coupled with evaporative light-scattering detector (HPLC-ELSD) techniques, 42 lipid components in coix seeds were identified, and seven molecular species of TAG in coix seeds from different localities in China were measured and compared, respectively. A correlation analysis between the morphological features and TAGs contents revealed the integrity instead of the particle size of the seed, displaying a highly positive correlation with its quality. The higher contents of TAGs in hulled coix seed than in polished coix seed proposed an alternative processing way. During storage, the changes in TAGs contents of seeds indicated that the storage period should be less than 3 months, and the intact seeds could maintain lipid stability better than the powder. Furthermore, the air humidity and temperature should be controlled during coix seed storage to prevent the production of mycotoxins. These results provide significant insight into the effective control of coix seed quality during processing and storage.

Separation of triacylglycerols containing positional isomers of hexadecenoic acids by enantiomeric liquid chromatography-mass spectrometry

Triacylglycerols (TAGs) containing positional isomers of hypogeic (Hy), palmitoleic (Po), and palmitvaccenic (Pv) acids from three microorganisms (top-fermenting brewer's yeast Saccharomyces cerevisiae, green alga Coccomyxa elongata, and arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis) were analyzed. Dozens of regioisomers and enantiomers of TAGs containing one, two or three hexadecenoic acids have been identified by means of reversed phase chromatography/mass spectrometry (RP-HPLC/MS). The regioisomers of TAGs containing two palmitic acids and any hexadecenoic acid were separated. Analysis of regioisomers of TAGs having one Pv residue showed that asymmetric molecular species such as PvPP or PPPv were dominant in Rhizophagus. TAGs were also analyzed on a chiral phase column and nine molecular species of TAGs containing two palmitic and any of three hexadecenoic acids were separated and identified. In the case of TAGs containing one palmitic and two hexadecenoic acids, the separation was successful only if the hexadecenoic acids were identical. Separation of TAGs containing three hexadecenoic acids was successful only if all three hexadecenoic acids were identical. Regardless of the type of TAG, it was found that TAGs in the AM fungus and containing palmitvaccenic acid bound at the sn-1 position of the glycerol backbone were dominant, suggesting similarity in the biosynthesis of the different TAGs. The covalent adduct chemical ionization method was used for identification of TAGs as adduct with (1-methyleneimino)-1-ethenyl ion, which reacted with double bond of the unsaturated fatty acid. Tandem MS thus makes it possible to identify TAGs containing various hexadecenoic acids.

Suppression of Physaria fendleri SDP1 Increased Seed Oil and Hydroxy Fatty Acid Content While Maintaining Oil Biosynthesis Through Triacylglycerol Remodeling.

Physaria fendleri is a burgeoning oilseed crop that accumulates the hydroxy fatty acid (HFA), lesquerolic acid, and can be a non-toxic alternative crop to castor for production of industrially valuable HFA. Recently, P. fendleri was proposed to utilize a unique seed oil biosynthetic pathway coined “triacylglycerol (TAG) remodeling” that utilizes a TAG lipase to remove common fatty acids from TAG allowing the subsequent incorporation of HFA after initial TAG synthesis, yet the lipase involved is unknown. SUGAR DEPENDENT 1 (SDP1) has been characterized as the dominant TAG lipase involved in TAG turnover during oilseed maturation and germination. Here, we characterized the role of a putative PfeSDP1 in both TAG turnover and TAG remodeling. In vitro assays confirmed that PfeSDP1 is a TAG lipase and demonstrated a preference for HFA-containing TAG species. Seed-specific RNAi knockdown of PfeSDP1 resulted in a 12%–16% increase in seed weight and 14%–19% increase in total seed oil content with no major effect on seedling establishment. The increase in total oil content was primarily due to ~4.7% to ~14.8% increase in TAG molecular species containing two HFA (2HFA-TAG), and when combined with a smaller decrease in 1HFA-TAG content the proportion of total HFA in seed lipids increased 4%–6%. The results are consistent with PfeSDP1 involved in TAG turnover but not TAG remodeling to produce 2HFA-TAG. Interestingly, the concomitant reduction of 1HFA-TAG in PfeSDP1 knockdown lines suggests PfeSDP1 may have a role in reverse TAG remodeling during seed maturation that produces 1HFA-TAG from 2HFA-TAG. Overall, our results provide a novel strategy to enhance the total amount of industrially valuable lesquerolic acid in P. fendleri seeds.

A Comparative Study of Milk Fat Extracted from the Milk of Different Goat Breeds in China: Fatty Acids, Triacylglycerols and Thermal and Spectroscopic Characterization.

Goat milk (GM) is an excellent alternative to cow milk and has recently been used in commercial infant formula preparation due to its superior fat composition. Here, the fatty acid (FA) composition, triacylglycerol (TAG) molecular species, thermal behavior and infrared spectra of extracted milk fat from the milk of the two main breeds of dairy goat bred in China (Guanzhong GM (GZG) and Xinong Saanen GM (XSG)) are investigated. Gas chromatography, Fourier-transform infrared spectroscopy, differential scanning calorimetry and ultra-performance convergence chromatography with quadrupole time-of-flight mass spectrometry are applied. The obtained results evidence significant fat compositional differences based on the breed that produced the considered GM. The major FAs in both GM fats were capric (C10:0), myristic (C14:0), palmitic (C16:0), stearic (C18:0) and oleic (C18:1 n-9c). GZG presented a higher content of medium-chain saturated FAs, while XSG had higher unsaturated FAs with higher ratios of L/Ln and n-6/n-3. A total of 339 and 359 TAGs were detected and quantified in GZG and XSG, and the major TAGs were those of m/z 740.6712 (14.10 ± 0.27%) and m/z 684.6094 (10.94 ± 0.02%), respectively. Milk TAGs of GZG and XSG showed 24–54 and 26–54 total acyl carbon numbers with a 0–4 and 0–5 double bond number at 68 and 72 various retention times, respectively. Thermal analysis showed that all GM fat samples melted below normal body temperature. Infrared spectra revealed higher absorption values of GZG milk fat. This study provides valuable information to the dairy industry sector about GM fat produced in China, assessing the appropriateness of Chinese GM fat to be applied in Chinese infant formula.

Overexpression of phospholipid: diacylglycerol acyltransferase in Brassica napus results in changes in lipid metabolism and oil accumulation.

The regulation of lipid metabolism in oil seeds is still not fully understood and increasing our knowledge in this regard is of great economic, as well as intellectual, importance. Oilseed rape (Brassica napus) is a major global oil crop where increases in triacylglycerol (TAG) accumulation have been achieved by overexpression of relevant biosynthetic enzymes. In this study, we expressed Arabidopsis phospholipid: diacylglycerol acyltransferase (PDAT1), one of the two major TAG-forming plant enzymes in B. napus DH12075 to evaluate its effect on lipid metabolism in developing seeds and to estimate its flux control coefficient. Despite several-fold increase in PDAT activity, seeds of three independently generated PDAT transgenic events showed a small but consistent decrease in seed oil content and had altered fatty acid composition of phosphoglycerides and TAG, towards less unsaturation. Mass spectrometry imaging of seed sections confirmed the shift in lipid compositions and indicated that PDAT overexpression altered the distinct heterogeneous distributions of phosphatidylcholine (PC) molecular species. Similar, but less pronounced, changes in TAG molecular species distributions were observed. Our data indicate that PDAT exerts a small, negative, flux control on TAG biosynthesis and could have under-appreciated effects in fine-tuning of B. napus seed lipid composition in a tissue-specific manner. This has important implications for efforts to increase oil accumulation in similar crops.

Lipidome analysis and metabolite profiling of fixed oils from selected spices

Fixed oils are potential treasures of various bioactive compounds. Here, we extracted fixed oils from spices, namely Cinnamomum cassia, Amomum subulatum, Punica granatum L., Papaver somniferum L., Elettaria cardamomum L., Tamarindus indica L., and Cinnamomum tamala, and studied their fatty acid and triacylglycerol (TAG) composition. It was observed that P. somniferum (47.09%) yielded the highest amount of fixed oil. Gas chromatography-mass spectrometry profiling of the fixed oils showed the presence of oleic, linoleic, and palmitic acids. Lipidome analysis via high-resolution mass spectrometry confirmed large diversity of TAG molecular species ranging from C38:0 to C60:4. Further, the antioxidant potential and nutraceutical profile of fixed oils were studied by determining the phenolics, tocopherols, sterols, and squalene content through high-performance liquid chromatography (HPLC). Hydroxybenzoic acid, trans -cinnamic acid, p -coumaric, and kaempferol were the dominant phenolic compounds present in the studied fixed oils. HPLC confirmed the highest amounts of α-tocopherol in C. tamala (282.42 mg/100 g oil) and T. indica (251.89 mg/100 g oil) fixed oils. The β-sitosterol was the major sterol in all the studied fixed oils. The study enhances our understanding of lipids and secondary metabolites from fixed oils and paves way for its nutraceutical and industrial applications.

Evaluation of total, sn-2 fatty acid, and triacylglycerol composition in commercial infant formulas on the Chinese market: A comparative study of preterm and term formulas

Preterm infants with physiological immaturity require higher lipid provision than term infants. This study compared the lipid composition, including total, sn-2 fatty acid, and triacylglycerol (TAG) compositions in 14 preterm formulas and 25 term formulas in the Chinese market, in 2020–2021. Preterm formula had higher medium-chain fatty acid (MCFA) and comparable C22:6n-3 (DHA) contents than term formula. Notably, significantly lower C16:0 and C18:0 (p < 0.001) were distributed on the sn-2 position in preterm formula. Two hundred and thirteen kinds of TAG molecular species were identified using UPLC-Q-TOF-MS. In preterm formula, significantly higher Ca-Ca-Cy and Ca-Ca-Ca (p < 0.001) existed. These clear distinctions showed the challenge of the progress in preterm formula, such as DHA status, MCFA pattern, and TAG esterified with palmitic acid on the sn-2 position.

Investigation of the antioxidation capacity of gallic acid and its alkyl esters with different chain lengths for dried oyster during ambient storage

SummaryThe antioxidant capacity of gallic acid (GA) and its fatty alkyl esters such as butyl gallate, octyl gallate (OG), lauryl gallate and hexadecyl gallate in freeze‐dried oyster was investigated. During ambient storage, the significant increase of peroxide value and thiobarbituric acid value together with the decline for docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) contents indicated the occurrence of lipid autoxidation in freeze‐dried oysters. Meanwhile, the oxidative degradation of glycerol phosphocholine (GPC), glycerol phosphoethanolamine (GPE) and triacylglycerols (TAG) molecular species carrying DHA or EPA in oyster ranked as: TAG &gt; GPE &gt; GPC. GA and its alkyl esters could effectively be prevented dried oyster lipid from oxidation. Among them, OG stood out as the most effective individual. This work implied that the chain lengths of GA alkyl esters affect their antioxidant ability for dried oysters, which provides the information for selecting eligible antioxidants to enhance the oxidative stability of freeze‐dried seafood.

Physical and chemical properties of nabak (Zizyphus spina-christi) seed kernel and sweet pepper (Capsicum annuum L.) seed oils.

Nabak seed kernels and sweet pepper seeds, which are separated from the fruits and discarded as waste after processing or consumption, contain high levels of oils (30.19% and 19.57%, respectively). The chemical and thermal characteristics of nabak seed kernel oil (NSO) and sweet pepper seed oil (PSO) were investigated in this study. The NSO and PSO contained high levels of unsaturated fatty acids (84.1% and 86.5%, respectively), and the major fatty acid was oleic acid (57.3%) in NSO, but it was linoleic acid (69.4%) in PSO. The triacylglycerol (TAG) profiles show that NSO contained ten TAG species, three of which represented 87.1%, namely C54:3, C52:2 and C54:4, and triolein was the dominant (OOO, 47.0%). Pepper seed oil contained nine TAG molecular species, four of which represented 93.6%, namely C54:6, C52:4, C54:4 and C52:5, and trilinolein was dominant (LLL, 44.0%). The differential scanning calorimetry (DSC) analysis of NSO revealed that three exothermal peaks were detected during cooling, two endothermal peaks were detected during melting, and the major peak occurred at a low temperature. For PSO, three exothermal peaks were detected during cooling, three peaks were detected (one of them was exothermal) during melting, and the major peaks were observed at low temperatures. Fourier transform infrared (FTIR) spectra indicated that NSO and PSO did not contain peroxides or trans fatty acids, but they did contain low concentrations of free fatty acids. This study offers a scientific basis for the use of NSO and PSO as new sources of edible oils for food applications. © 2021 Society of Chemical Industry.

α-Linolenic acid and product octadecanoids in Styrian pumpkin seeds and oils: How processing impacts lipidomes of fatty acid, triacylglycerol and oxylipin molecular structures

Styrian pumpkin seed oil is a conditioned green-colored oil renowned for nutty smell and taste. Due to α-linolenic acid (ALA) contents below 1% of total fatty acids and the prospect of nutritional health claims based on its potential oxidation products, we investigated the fate of ALA and product oxylipins in the course of down-stream processing of seeds and in oils. Lipidomic analyses with Lipid Data Analyzer 2.8.1 revealed: Processing did not change (1) main fatty acid composition in the oils, (2) amounts of triacylglycerol species, (3) structures of triacylglycerol molecular species containing ALA. (4) Minor precursor ALA in fresh Styrian and normal pumpkins produced 6 product phytoprostanes in either cultivar, quantitatively more in the latter. (5) In oil samples 7 phytoprostanes and 2 phytofurans were detected. The latter two are specific for their presence in pumpkin seed oils, of note, quantitatively more in conditioned oils than in cold-pressed native oils.