Oil Triacylglycerols Research Articles

Evaluation of 1,2-diacyl-3-acetyl triacylglycerol production in Yarrowia lipolytica

Plants produce many high-value oleochemical molecules. While oil-crop agriculture is performed at industrial scales, suitable land is not available to meet global oleochemical demand. Worse, establishing new oil-crop farms often comes with the environmental cost of tropical deforestation. The field of metabolic engineering offers tools to transplant oleochemical metabolism into tractable hosts while simultaneously providing access to molecules produced by non-agricultural plants. Here, we evaluate strategies for rewiring metabolism in the oleaginous yeast Yarrowia lipolytica to synthesize a foreign lipid, 3-acetyl-1,2-diacyl-sn-glycerol (acTAG). Oils made up of acTAG have a reduced viscosity and melting point relative to traditional triacylglycerol oils making them attractive as low-grade diesels, lubricants, and emulsifiers. This manuscript describes a metabolic engineering study that established acTAG production at g/L scale, exploration of the impact of lipid bodies on acTAG titer, and a techno-economic analysis that establishes the performance benchmarks required for microbial acTAG production to be economically feasible.

Influence of 1,3-diacylglycerol on physicochemical and digestion properties of nanoemulsions and its enhancement of encapsulation and bioaccessibility of hydrophobic nobiletin.

Lipid-based delivery systems are commonly used to encapsulate hydrophobic bioactive compounds for enhancing their bioaccessibility and bioavailability, especially for triacylglycerol (TAG) oil-based delivery systems. However, studies on the development of 1,3-diacylglycerol (DAG) oil-based delivery systems are rather limited. Herein, the influence of 1,3-DAG oil as a carrier oil on the properties of nanoemulsions and the bioaccessibility of encapsulated hydrophobic nobiletin (NOB) were investigated. High-purity 1,3-DAG (over 93% pure) was prepared by a combination of enzymatic esterification and ethanol crystallization. 1,3-DAG oil as a carrier oil could be used to formulate nanoemulsions with smaller droplet size, narrower size distribution and similar stability compared to TAG oil. Importantly, 1,3-DAG oil could efficiently encapsulate high-loading NOB (1.45 mg g-1) in nanoemulsions and significantly improve the bioaccessibility of NOB (above 80%), which is attributable to its massive lipolysis and higher encapsulation capacity than TAG oil. Moreover, the addition of the 1,3-DAG component in TAG oil significantly improved the properties of nanoemulsions and the loading and bioaccessibility of NOB, especially as the 1,3-DAG content was not less than 50%. The structure of lipids (DAG versus TAG) influenced the nanoemulsion properties and the bioaccessibility of encapsulated NOB. Based on the good properties of 1,3-DAG oil coupled with its health benefits, 1,3-DAG oil-based nanoemulsion delivery systems have great prospects for improving and extending emulsion properties and bioactivity as well as bioaccessibility enhancement.

Application of camellia oil-based diacylglycerol and its solid fractions in soft ice cream

Ice cream products are sweet and rich in taste, which make them popular desserts among consumers. However, the high-fat and high-sugar contents in ice creams may result in multiple health conditions after prolonged consumption. Camellia oil-based diacylglycerol (CD) oil can reduce the body fat accumulation due to their different metabolic pathways from triacylglycerol (TAG) oil. It is believed that the long-term consumption of CD can improve human’s health by lowering the plasma TAG and blood sugar levels. Nevertheless, CD is unsuitable for direct application in ice cream products due to its low solid fat content (SFC). Therefore, in the present work, fractionation was attempted to increase the SFC of the CD. Subsequently, camellia oil, CD, and its solid fractions were characterised and further incorporated in ice cream formulations. It was found that fractionation significantly (p < 0.05) increased the SFC of the CD. The solid fractions of CD exhibited similar physicochemical properties with the oils/fats commonly used for ice cream production, namely palm olein and milk fat. At 0°C, the SFC of the CD solid fractions was 29.33%; whereas at 37°C, the SFC decreased rapidly, which enabled them to melt quickly in the mouth. At the same time, CD solid fractions were rich in β'-form crystals which contributed to the rich, delicate, and smooth texture for ice cream products. The ice cream formulated with CD solid fractions showed better overrun (48.24%) and hardness (594.18 g) as compared to the ice creams prepared with camellia oil (with the overrun and hardness of 41.27% and 524.36 g, respectively) and CD (with the overrun and hardness of 39.77% and 284.31 g, respectively). The substitution of TAG with CD solid fractions made the formulated ice cream product a healthier dessert, and at the same time provided similar organoleptic properties as conventional ice creams.

Fabrication and characterisation of spice essential oil‐based nanoemulsions: physical, sensory and antimicrobial properties

SummarySpice essential oils (EOs) have been widely used in packaging, medicine and food industries due to their antimicrobial, health benefits and flavour functions. However, the strong organoleptic characteristics, non‐digestibility and high volatility have limited the application of emulsions made from a single type of spice EO. In this work, sunflower oil and spice EOs (i.e., garlic EO, ginger EO, Sichuan pepper EO) were mixed with different mass ratios (sunflower oil: spice EO = 1:0, 9:1, 5:1, 3:1, 1:1 and 0:1) as oil phase to produce various nanoemulsions. Physical, sensory and antimicrobial properties of spice EO‐based nanoemulsions were investigated considering the droplet size, turbidity, stability, colour, flavour, minimum inhibitory concentration and minimum bactericidal concentration. The results showed that the nanoemulsions prepared with a mixing ratio of 1:1 all had the minimum droplet size and the minimum PDI value, which were about 150 nm and 0.1, respectively. The temperature‐accelerated test and the gravitational stability experiment demonstrated that the mixed oil phase‐based nanoemulsions were more stable than pure spice EO phase‐based emulsions. The colour test and flavour test results showed that the type of spice EO and the mixing ratio of the mixed‐oil phase had obvious effects on the sensory properties of the emulsion. Moreover, the mixed‐oil nanoemulsions with superior stability did not impair the antimicrobial activity of the spice EOs. This study provides a guideline on the rational design of emulsion‐based systems using triacylglycerol oil and spice EOs in combination to produce nanoemulsions with superior stability, sensory property and antibacterial activity.

Transesterification of castor oil catalyzed by a fermented solid produced by Burkholderia contaminans using a bioreactor coupled with ultrasound irradiation.

In this work, ultrasound was used to assist the ethanolysis of castor oil in a solvent-free system, catalyzed by a dry fermented solid containing the lipase from Burkholderia contaminans (BCFS). Reactions were done at 45°C. The maximum conversion in Erlenmeyer flasks was 71% in 96h, using a loading of 9% (mass of BCFS in relation to the mass of triacylglycerols in the castor oil) and a molar ratio of ethanol:oil of 6:1, with addition of ethanol in 12 steps. In a packed-bed reactor containing 12g of BCFS, the conversions were 78% in 48h, and 83% in 72h with an ethanol to oil molar ratio of 3:1 and treatment with an ultrasound probe, with maximum power of 500W, frequency of 20kHz, and 75% of the maximum power. These results are promising given that, with an ultrasound assisted bioreactor, a higher conversion in a shorter time was achieved, with a lower ethanol to oil molar ratio than was the case in the Erlenmeyer flasks without ultrasound.

Potential use of the bioactive compounds of the olive mill wastewater: Monitoring the aldehydes, phenolic compounds, and polymerized triacylglycerols in sunflower and olive oil during frying

The current study aims to investigate the application of the olive mill wastewater (OMW) extract (100 ppm) as additive to the refined sunflower oil and olive oil to reduce the formation of the oxidation products during deep frying of chicken and potato. The production of polymerized triacylglycerols (pTAG) and aldehydes was lower during frying in olive oil than in enriched refined oil. The highest percentage of polyunsaturated fatty acids in refined oil exhibits a great tendency to form polymeric compounds. The enrichment of sunflower oil with OMW extract reduces the formation of pTAG and aldehydes, whereas the enrichment of olive oil with OMW extract showed an increase in the formation of pTAG and promoted the biosynthesis of aldehydes whose rate remains significantly lower than that observed in enriched sunflower oil. The production of polymerized and aldehydic compounds was more pronounced when chicken was fried compared with potatoes. For the phenolic alcohols, their degradation was reached at the end of the experimentation. Novelty impact statement Olive mill wastewater (OMW) is a source of bioactive molecules that can be extracted and valorized in several industrial sectors. OMW extract reduces the production of p-TAG and aldehydic products during frying foods in refined sunflower oils Frying of foods in olive oil without any additive is healthier than frying in enriched refined oils.

Using field evaluation and systematic iteration to rationalize the accumulation of omega-3 long-chain polyunsaturated fatty acids in transgenic Camelina sativa.

SummaryThe Brassicaceae Camelina sativa (gold of pleasure) is now an established niche crop and being used as a transgenic host for a range of novel seed traits. Most notable of these is the accumulation of omega‐3 long‐chain polyunsaturates such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), fatty acids normally only found in marine organisms. As part of continued efforts to optimize the accumulation of these non‐native fatty acids via seed‐specific expression of algal genes, a new series of iterative constructs was built and introduced into Camelina. Seed fatty acid composition was determined, and the presence of EPA and DHA was confirmed. To provide an additional level of evaluation, full environmental release was carried out on selected events, providing a real‐world gauntlet against which to assess the performance of these novel lines. Composition of the seed oil triacylglycerol was determined by mass spectrometry, allowing for conclusions as to the contribution of different activities to the final accumulation of EPA and DHA. Since these data were derived from field‐grown material, they also represent a robust demonstration of the stability of the omega‐3 LC‐PUFA trait in Camelina. We propose that field trialling should be routinely incorporated in the plant synthetic biology ‘design–build–test–learn’ cycle.

A novel UHPLC-ESI-MS/MS method and automatic calculation software for regiospecific analysis of triacylglycerols in natural fats and oils

Regioisomeric analysis of triacylglycerols (TAGs) in natural oils and fats is a highly challenging task in analytical chemistry. Here we present a software (TAG Analyzer) for automatic calculation of regioisomeric composition of TAGs based on the mass spectral data from recently reported ultra-high performance liquid chromatography electrospray ionization tandem mass spectrometry (UHPLC−ESI−MS/MS) method for analyzing TAG regioisomers. The software enables fast and accurate processing of complex product ion spectra containing structurally informative diacylglycerol [M+NH4−RCO2H–NH3]+ and fatty acid ketene [RCO]+ fragment ions. Compared to manual processing, the developed software offers higher throughput with faster calculation as well as more accurate interpretation of chromatographically overlapping isobaric TAGs. The software determines results by constructing a synthetic spectrum to match the measured fragment ion spectrum, and by reporting the optimal concentrations of TAGs used to create the synthetic spectrum. This type of calculation is often extremely challenging for manual interpretation of the fragment ion spectra of isobaric TAGs with shared fragments, hence the need for automated data processing. The developed software was validated by analyzing a wide range of mixtures of regiopure TAG reference compounds of known composition and a commercial olive oil sample. Additionally, the method was also applied for regiospecific analysis of TAGs in human milk as an example of natural fats and oils with a highly complex TAG profile. The results indicate that the software is capable of resolving regioisomeric composition of natural TAGs even of the most complex composition. This novel calculation software combined with our existing UHPLC-ESI-MS/MS method form a highly efficient tool for regioisomeric analysis of TAGs in natural fats and oils.

The digestion of diacylglycerol isomers by gastric and pancreatic lipases and its impact on the metabolic pathways for TAG re-synthesis in enterocytes

The specific activities of gastric and pancreatic lipases were measured using triacylglycerols (TAG) from rapeseed oil, purified 1,3-sn-DAG and 1,2(2,3)-sn-DAG produced from this oil, as well as a rapeseed oil enriched with 40% w/w DAG (DAGOIL). Gastric lipase was more active on 1,3-sn-DAG than on 1,2(2,3)-sn-DAG and TAG, whereas pancreatic lipase displayed a reverse selectivity with a higher activity on TAG than on DAG taken as initial substrates. However, in both cases, the highest activities were displayed on DAGOIL. These findings show that DAG mixed with TAG, such as in the course of digestion, is a better substrate for lipases than TAG. The same rapeseed oil acylglycerols were used to investigate intestinal fat absorption in rats with mesenteric lymph duct cannulation. The levels of TAG synthesized in the intestine and total fatty acid concentration in lymph were not different when the rats were fed identical amounts of rapeseed oil TAG, 1,2(2,3)-sn-DAG, 1,3-sn-DAG or DAGOIL. Since the lipolysis of 1,3-sn-DAG by digestive lipases leads to glycerol and not 2-sn-monoacylglycerol (2-sn-MAG) like TAG lipolysis, these results suggest that the re-synthesis of TAG in the enterocytes can entirely occur through the “glycerol-3-phosphate (G3P)” pathway, with the same efficiency as the 2-sn-MAG pathway predominantly involved in the intestinal fat absorption. These findings shed new light on the role played by DAG as intermediate lipolysis products. Depending on their structure, 1,2(2,3)-sn-DAG versus 1,3-sn-DAG, DAG may control the pathway (2-sn-MAG or G3P) by which TAG are re-synthesized in the enterocytes.

Women have higher levels of CoQ10 than men when supplemented with a single dose of CoQ10 with monoglycerides omega-3 or rice oil and followed for 48 h: a crossover randomised triple blind controlled study

Coenzyme Q10 (CoQ10), a lipid involved in ATP synthesis, exhibits very limited oral absorption, and its endogenous production decreases with ageing and with the occurrence of oxidative stress. Our group previously showed that monoglycerides omega-3 (MAG-OM3) increase OM3 plasma concentrations. Since CoQ10 is liposoluble, we hypothesised that its 48 h pharmacokinetics is higher when provided with MAG-OM3 compared to CoQ10 alone (in powder form) or added to rice oil (a neutral triacylglycerol oil). A randomised triple-blind crossover study was performed with fifteen men and fifteen women consuming the three supplements providing 200 mg of CoQ10 in a random order. Blood samples were collected before (t = 0) and 1, 3, 5, 6, 7, 8, 10, 11, 24 and 48 h after the supplement intake. Plasma total CoQ10 concentrations were analysed on ultrahigh-performance liquid chromatography coupled to a tandem mass spectrometer (UPLC-MS/MS). Participants were 26⋅1 ± 4⋅8 years old. When CoQ10 was provided with rice or MAG-OM3 oils, the 48 h area under the curve (AUC 0-48 h) was approximately two times higher compared to when provided without an oil. The delta max concentration (ΔC max) of plasma CoQ10 was, respectively, 2 (MAG-OM3) and 2⋅5 (rice oil) times higher compared to CoQ10 alone. There was a significant sex by treatment interaction (P = 0⋅0250) for the AUC 0-6 h supporting that in postprandial, men and women do not respond the same way to the different supplement. Women had a higher CoQ10 concentration 48 h after the single-dose intake compared to men. We conclude that CoQ10 supplements must be provided with lipids, and their kinetics is different between men and women.

Soybean oil-based monoacylglycerol synthesis using bio-compatible amino acid ionic liquid as a catalyst at low temperature

Monoacylglycerol (MAG) from edible oil is one kind of green and safe food additive. This project mainly focused on a nontoxic and biodegradable catalyst, amino acid-based ionic liquids (AAILs), for the glycerolysis of soybean oil triacylglycerol (TAG) to prepare MAG at low temperature. Seven AAILs, from arginine, lysine, histidine, tryptophan, or glutamic acid and choline hydroxide, tetramethylhydroxide ammonium, or tetrabutylammonium hydroxide, were successfully synthesized in this work. The effects of substrate ratio, AAIL load, temperature, and reaction time on AAIL-catalyzed the glycerolysis of soybean oil were evaluated. Moreover, the activation energy of MAG formation was explored and reaction mechanism was also proposed. Finally, reaction conditions were optimized by response surface methodology. Results showed that, among all tested AAILs, [TMA][Arg] prepared by arginine (Arg) and tetramethylhydroxide ammonium (TMAOH) showed the outstanding catalytic performance for the glycerolysis of soybean oil. The maximum MAG yield (64.89 ± 1.26%) and TAG conversion (86.31 ± 1.68%) were achieved under the optimized conditions: 105 °C, 0.5 h, [TMA][Arg] load 10%, and substrate molar ratio 1:2 (soybean oil/glycerol). Moreover, the activation energies of MAG formation and TAG conversion were 44.22 kJ/mol and 37.58 kJ/mol, respectively.

Effect of Steric Structure on the Mechanism of Antioxidant Activity of Alkyl Gallates in Soybean Oil Triacylglycerols—A Kinetic Approach

AbstractFrom an interfacial phenomena standpoint, the effect of the alkyl chain length is evaluated on the mechanism of antioxidant activity of gallic acid ester derivatives (methyl, propyl, octyl, dodecyl, and stearyl gallates) in bulk phase oil. A combinational kinetic model is used to estimate the oxidation kinetic parameters, such as induction period, the maximum concentration of lipid hydroperoxides, and critical reverse micelle concentration. These kinetic parameters are estimated much better with the combinational model compared to the tangent method. The nonlinear behavior is observed for inhibitory activities of homologous series of antioxidants in soybean triacylglycerols. In terms of different kinetics parameters, including antioxidant effectiveness and activity, methyl gallate has the highest inhibitory effect during lipid peroxidation. Gallic acid and alkyl gallates are able to protect bulk oils against peroxidation (induction period > 336 h) in terms of the extent of their participation in the main reaction of chain termination and pro‐oxidative side reactions of chain initiation, and anti‐oxidative side reactions of chain propagation.Practical Applications: This work explains the effect of the esterification in the inhibitory activity of alkyl gallates, mechanism action of alkyl gallates in bulk oil systems, antiradical potency as a function of the interfacial phenomena, and free radical chain mechanism, the impact of antioxidant activity on critical reverse micelle concentration of hydroperoxides. Moreover, in this study, it is confirmed that the combinational kinetic model can be employed as a reliable method for determining the oxidation kinetic parameters.

Epoxidized linseed lipids as a durable and fast-curing alternative to drying oils

Linseed and other unsaturated plant oils continue to be important natural finishes for wood protection. However, they suffer from long drying times and reduced durability due to their susceptibility to microbial colonization. Response surface modelling was used to study the effect of linseed fatty acid methyl ester (ELOME) addition on the curing of epoxidized linseed oil triacylglycerols (ELO) under ultraviolet (UV) light, as an alternative to air-drying of unmodified linseed oil. We found that the hydrolytic (abiotic and enzymatic) degradation was reduced by 20% compared to air-dried linseed oil due to ether cross-link formation at high degrees of epoxy group conversion (≥80%) in the presence of ELOME. Curing under solar irradiation was also tested using curcumin, a natural photosensitizer. In this case, it was found that that oxygen inhibition limited cross-linking on wood surfaces and in thin films unless a tertiary amine is present to scavenge oxygen. A desirability function approach concluded that epoxidized linseed lipids containing a high content of ELOME (75 wt% to 85 wt%) and moderate concentrations of the photoinitiator (35 wt% to 5 wt%), are good alternatives to linseed oil, resulting in films with a similar glass transition temperature but with the benefits of faster curing (seconds to minutes, compared to days or weeks) and improved hydrolytic stability. Such films still maintain a biorenewable content of >93%.

Efficacy of rosemary (Rosmarinus officinalis L.) powder and extracts in the protection of refined and stripped hazelnut oil

In this study, the antioxidant activity of rosemary (Rosmarinus officinalis L.) extracts or dried rosemary on the oxidative stability of hazelnut oil and its purified triacylglycerols (TAGs) was investigated. The antioxidant activities of rosemary extracts tested using different methods were similar to BHT and α-tocopherol at 0.25–20 mg/mL. Induction period (IP) is the time at which the onset of oxidation occurred was determined using differential scanning calorimeter (DSC) at 150 °C under oxygen pressure. The induction periods of hazelnut oils containing rosemary extracts (0.25–2.0 mg/g) and/or dried rosemary (10–200 mg/g) were higher than that of control at 150 °C, and their protection factors were in the range of 1.3 and 2.2. The induction period of hazelnut oil TAGs was 3.93 min, while those of TAGs containing rosemary methanol extracts at 1 mg/g or dried rosemary at 50 mg/g were 21.46 min and 27.19 min, respectively. According to the accelerated oxidation test at 60 °C, peroxide value, K232, and K268 values of hazelnut oil with rosemary extracts or dried rosemary were lower than those of control. Dried rosemary at 50 mg/g was the most effective supplement in hazelnut oil protection against oxidation. In conclusion, both dried rosemary and its alcohol extracts could be used to increase oxidative stability of hazelnut oil.

Is dietary phosphatidylcholine essential for juvenile slipper lobster (Thenus australiensis)?

Phospholipids, especially phosphatidylcholine (PC), are considered essential nutrients for larval and juvenile stages of many decapod crustacean species due to low rates of endogenous biosynthesis and potential nutritional benefits in assisting lipid digestion and transport. This study was conducted to test the hypothesis that dietary PC is essential and would subsequently have beneficial effects on lipid utilisation and digestibility of fish oil triacylglycerol (TAG) in the slipper lobster, Thenus australiensis. Juvenile slipper lobsters were supplied six formulated experimental feeds with actual PC contents of 0.05, 0.48, 0.65, 0.98, 1.15 and 1.43% (dry matter) for 12 weeks. Manipulating dietary PC content had no effects on survival, growth, chemical composition, whole body or tissue lipid distribution, or apparent digestibility (AD) of gross energy (GE), total lipid (TL) or PC. Juvenile slipper lobsters appeared to possess fully developed and efficient mechanisms for GE, TAG and PC digestion (>95% AD). In vivo lipid class mass balance calculations demonstrated net intake of TL and TAG was considerably greater than was accumulated in the whole-body during growth. Thus, a significant proportion of dietary TL and TAG was utilised for energy and other metabolic processes. In contrast, particularly for low PL dietary treatments (≤ 0.5%), net gain of PC was greater than net intake, indicating a reliance on biosynthesis of PC. Thus, it is concluded that there is no or a very low requirement for dietary PC and thus may not be essential for the examined size class of juvenile T. australiensis when supplied adequate dietary PC biosynthetic precursors and other potentially related dietary nutrients. Further targeted research is recommended to verify if these findings are applicable to larval and early juvenile stages, and to enhance overall understanding of lipid nutritional requirements for T. australiensis.

Trans triacylglycerols from dairy products and industrial hydrogenated oil exhibit different effects on the function of human umbilical vein endothelial cells via modulating phospholipase A2/arachidonic acid metabolism pathways

Dairy fat intake has been considered as a risk factor for cardiovascular disease. Rodent models show that trans fatty acids in industrial hydrogenated oil and ruminant milk have different effects on cardiovascular diseases. One of the main reasons is that the distributions of trans fatty acids in triacylglycerols from dairy products and from industrial hydrogenated oil are different, which affects lipid absorption and metabolism. This study investigated the effects of 1,3-olein-2-elaidin (OEO, representing industrial hydrogenated oil triacylglycerols) and 1-vaccenic-2,3-olein (OOV, representing ruminant triacylglycerols in dairy products) on the function of human umbilical vein endothelial cells (HUVEC), including cell viability, lactate dehydrogenase (LDH) exudation rate, and nitric oxide secretory and nitric oxide synthase relative activity. We found that the detrimental effect of OEO on HUVEC was significantly greater than that of OOV. The results also showed that the absorption rate of OEO in HUVEC (78.25%) was significantly greater than that of OOV (63.32%). Mechanistically, based on phospholipidomics analysis, we found that calcium-independent phospholipase A2 (iPLA2) played a key role with regard to the OOV-mediated arachidonic acid (ARA)/COX-2/PG pathway, whereas secretory phospholipase A2 (sPLA2) and cytoplasmic phospholipase A2 (cPLA2) are responsible for the OEO-mediated ARA/COX-2/PG pathway. Moreover, OEO had a greater effect on the protein expression of COX-2 and PG secretion than OOV. In addition, iPLA2, sPLA2, and cPLA2 could mediate the ARA/CYP4A11 pathway in OOV-treated HUVEC, but only iPLA2 could mediate this pathway in HUVEC treated with OEO. We also found that sPLA2 could mediate the ARA/5-LOX pathway in HUVEC treated with OOV, but none of these 3 forms of PLA2 could mediate this pathway in HUVEC treated with OEO. On the other hand, after OOV treatment, trans-11 C18:1 was converted to beneficial forms of fatty acids in HUVEC, including conjugated linoleic acid (CLA) and trans-9 C16:1. In conclusion, we elucidated the potential mechanisms that might account for the diverse effects of triacylglycerols from industrial hydrogenated oil and ruminant milk on the function of HUVEC.

Strategy for stereospecific characterization of natural triacylglycerols using multidimensional chromatography and mass spectrometry

Stereoisomeric determination of individual triacylglycerols (TAGs) in natural oils and fats is a challenge due to similar physicochemical properties of TAGs with different fatty acid combinations. In this study, we present a strategy to resolve the enantiomeric composition of nutritionally important TAGs in sea buckthorn (Hippophaë rhamnoides) as an example food matrix. The targeted strategy combines 1) fatty acid profiling with GC, 2) separation of TAGs with RP-HPLC, 3) stereospecific separation with chiral-phase HPLC and 4) structural characterization with MS. Three major asymmetric diacid- and triacid-TAG species were analyzed in sea buckthorn pulp oil. Off-line coupling of RP-HPLC and chiral-phase HPLC allowed separation of several TAG regioisomers and enantiomers, which could not be resolved using one-dimensional techniques. Enantiomeric ratios were determined and specific structural analysis of separated TAGs was performed using direct inlet ammonia negative ion chemical ionization method.Of the TAG 16:0/16:1/16:1 palmitic acid (C16:0) was located predominantly in a primary position and the enantiomeric ratio of TAG sn-16:1-16:1-16:0 to sn-16:0-16:1-16:1 was 70.5/29.5. Among the TAGs 16:0/16:0/18:2 and 16:0/16:0/16:1, only ca 5% had C16:0 in the sn-2 position, thus, ca 95% were symmetric sn-16:0-18:2-16:0 and sn-16:0-16:1-16:0. The enantiomeric ratio of triacid-TAGs containing C16:0 and two unsaturated fatty acids (palmitoleic C16:1, oleic C18:1 or linoleic acids C18:2) could not be resolved due to lack of commercial enantiopure reference compounds. However, it became clear that the targeted strategy presented offer unique and convenient method to study the enantiomeric structure of individual TAGs.

Palm Oil Processing and Controversies over Its Health Effect: Overview of Positive and Negative Consequences.

Palm oil is the world's most commonly used vegetable oil and extracted both from fruit and seed of palm tree. However, its high saturated fatty acid content raised controversies over consumption of the oil. Few scientific findings suggest it as a risk factor for cardiovascular disease and increased consumer's awareness over healthy diet raised claim over it. So that, this article aimed to review literatures on palm oil extraction process and its positive and negative health consequences and besides suggest strategies for healthy diet. Literature search of relevant articles was conducted by using Google scholar, PubMed, Web of science, MEDLINE, World Health Organization library online catalogue, UNICEF library, Open access thesis and dissertations published between 2009 and 2021 explored. Study reports recommend that palmitic acid from vegetable source has less effect on blood total cholesterol and low density lipoprotein cholesterol level as compared to palmitic acid from animal source. In contrary tocotrienols of palm oil lowers blood bad cholesterol level by 7-38%. Moreover, palm oil triacylglycerol arrangement does not have a cardiovascular risk and evidences from available in vitro and in vivo studies are not sufficient enough to conclude palm oil as a causative agent for cardiovascular disease. For healthy diet consumers should avoid trans fatty acids, solid and semi solid oils. Finally, further studies recommended on mitigation strategies to minimize process induced toxicants of palm oil to acceptable level.

Mechanism Controlling High‐Temperature Degradation of Sunflower Oil Triacylglycerols in the Absence of Oxygen

AbstractThe aim of the present study is to describe the mechanism controlling heat‐induced formation of sunflower oil triacylglycerol and fatty acid methyl ester oligomers. The unique combination of high‐performance size‐exclusion chromatography with hyphenated electrospray ionization mass spectrometry (MS), atmospheric pressure chemical ionization‐MS, and high‐temperature gas chromatography‐MS techniques allows differentiating between radical coupling species and Diels–Alder cycloadducts. Targeted analysis of thermally degraded sunflower oils confirms the exact structures of various acyclic oligomers accompanied by less‐abundant products of pericyclic transformations. A series of model experiments simulate the impact of dienophile nature on the course of Diels–Alder reactions. Thus, α‐tocopherylquinone, δ‐tocopherylquinone, and methyl‐(E)‐11‐oxoundec‐9‐enoate are synthesized as naturally occurring dienophiles bearing electron‐withdrawing groups. The geometry of poor dienophiles does not affect concerted cyclization, while the structure of electron deficient dienophiles can overcome low reactivity.Practical Application: In the absence of oxygen, heat‐induced degradation of polyunsaturated triacylglycerols proceed predominantly via a radical pathway, whereas concerted reactions represent minor mechanisms. Sunflower oil triacylglycerol molecules in the system without propagation stage can be effectively protected by natural and/or synthetic antioxidants. Application of chelates is also recommended. However, antioxidant‐derived quinones, such as α‐tocopherylquinone, can enter the Diels–Alder reaction even more easily than dienophiles without electron‐withdrawing groups. Unsaturated core aldehydes possess the same reactivity. Examination of the mechanism controlling high‐temperature degradation of triacylglycerols is especially important for processing engineers in edible oil refineries and food technologists. New perspective may help them to minimize undesirable changes in polyunsaturated species.

PHASE BEHAVIOUR OF HIGH, MEDIUM AND LOW MELTING FRACTIONS IN LAURIC FAT BLENDS FORMULATED BASED ON MELTING TRIACYLGLYCEROL GROUP

Lauric fat blends aimed for bakery shortening were prepared as a ternary mixture characterised by three distinct melting peaks on their differential scanning calorimeter (DSC) melting thermograms. Those melting peaks closely correlated to the high, medium, and low melting fractions (HMF, MMF and LMF) in the blends. In the simpler binary mixture, hard fats, (i.e. palm stearin and fully hydrogenated rapeseed oil) formed an ideal solubility in different liquid oils [i.e. medium chain triacylglycerol oil (MCI-oil) and high oleic sunflower oil (HOSO)]. However, slight deviations from ideality were observed when liquid oils were replaced by lauric oils (i.e. palm kernel oil and coconut oil). In the more complex ternary mixture, the I HMF formed an ideal solubility in both the MMF and LMF within the range of given formulas. In addition, the interaction of solid crystals in lauric fat blends was of monotectic behaviour as shown in the isosolid diagram. Nevertheless, the influence of solubility seemed to override that of solid interaction. Both the solubility curves and isosolid lines can provide valuable information about the interaction of HMF, MMF and LMF in lauric fat blends. Therefore, they are useful for improving the formulation of plastic fats.