Determination of the triacylglycerol content for the identification and assessment of purity of shea butter fat,peanut oil,and palm kernel oil using maldi-tof/tof mass spectroscopic technique

This article reports the rapid screening and identification of the triacylglycerol content of shea butter fat, palm kernel oil, and peanut oil sold in the local Ghanaian market for their characterization and identification. Samples were dissolved in chloroform with 2,5-dihydroxybenzoic acid as the matrix. After subjecting the samples to matrix-assisted laser desorption ionization-time-of-flight/mass spectrometry, the spectra obtained showed the characteristic triacylglycerols as sodium adducts. Seven major triacylglycerol species were identified as dipalmitoyl olein, palmitoyl diolein, palmitoyl stearoyl olein, linoleoyl diolein, triolein, stearoyl diolein, and distearoyl olein in all three samples. Palmitoyl linoleoyl olein and tristearin were also identified. Oxygenated triacylglycerols and other species from the fragmentation of triacylglycerols were also obtained. The presence of the oxygenated triacylglycerols and the triacylglycerol fragments may be a result of poor handling and production processes.     

Triacylglycerol Estolides,a New Class of Mammalian Lipids,in the Paracloacal Gland of the Brushtail Possum (Trichosurus vulpecula)

The paracloacal glands are the most prevalent scent glands in marsupials, and previous investigation of their secretions in the brushtail possum (Trichosurus vulpecula) has identified many odorous compounds together with large amounts of neutral lipids. We have examined the lipids by LC–MS, generating ammonium adducts of acylglycerols by electrospray ionisation. Chromatograms showed a complex mixture of coeluting acylglycerols, with m/z from about 404 to 1048. Plots of single [M + NH₄]⁺ ions showed three groups of lipids clearly separated by retention time. MS–MS enabled triacylglycerols and diacylglycerol ethers to be identified from neutral losses and formation of diacylglycerols and other product ions. The earliest‐eluting lipids were found to be triacylglycerol estolides, in which a fourth fatty acid forms an ester link with a hydroxy fatty acid attached to the glycerol chain. This is the first report of triacylglycerol estolides in animals. They form a complex mixture with the triacylglycerols and diacylglycerol ethers of lipids with short‐ and long‐chain fatty acids with varying degrees of unsaturation. This complexity suggests a functional role, possibly in social communication.     

Formation of Granular Crystals in Margarine with Excess Amount of Palm Oil

Crystallization behavior of palm oil and tripalmitin (PPP) in a model margarine system was investigated. The model margarine was held in a programmable oven, heated to 5 °C for 12 h and then 20 °C for a further 12 h. After 3 weeks, the model margarine was evaluated by polarization microscopy. Granular crystals were observed in the margarine containing an excess amount of palm oil and PPP. The concentration of higher-melting fatty acids was higher in the crystals relative to the surroundings. Likewise, the presence of lower-melting fatty acids was lower in the crystals. The polymorphic structure of the margarine with excess palm oil and PPP was determined to be all β′ by X-RD spectra. The result suggested that the agglomeration of higher-melting point triglycerides (TAGs), such as PPP in this study, led to the formation of granular crystals in the margarine without β polymorphic emergence.     

Dragon Fruit (Hylocereus spp.) Seed Oils: Their Characterization and Stability Under Storage Conditions

Oil was extracted from the seeds of white-flesh and red-flesh dragon fruits (Hylocereus spp.) using a cold extraction process with petroleum ether. The seeds contained significant amounts of oil (32–34 %). The main fatty acids were linoleic acid (C18:2, 45–55 %), oleic acid (C18:1, 19–24 %), palmitic acid (C16:0, 15–18 %) and stearic acid (C18:0, 7–8 %). The seed oils are interesting from a nutritional point of view as they contain a large amount of essential fatty acids, amounting to up to 56 %. In both dragon fruit seed oils, tri-unsaturated triacylglycerol (TAG) was mainly found while their TAG composition and relative percentage however varied considerably. Therefore, they showed a different melting profile. A significant amount of total tocopherols was observed (407–657 mg/kg) in which the α-tocopherol was the most abundant (~72 % of total tocopherol content). The impact of storage conditions, cold and room temperatures, on the oxidative stability and behavior of tocopherols was monitored over a 3-month storage period. During storage, the oxidative profile changed with a favorably low oxidation rate (~1 mequiv O₂/week) whilst tocopherols decreased the most at room temperature. After 12 weeks, the total tocopherol content, however, still remained high (65–84 % compared to the initial oils). Hereto, the dragon fruit seed oils can be considered as a potential source of essential fatty acids and tocopherols, with a good oxidative resistance.     

Growth and morphology of thin fat crystals

The experimental and theoretical morphology of fat crystals under non-diffusion limited conditions is reviewed. In addition, recent work on the effect of diffusion limited growth is reported. Growth rate versus supersaturation curves of various flat-needle shaped triacylglycerol crystals grown from solution or melt are presented. In most cases these curves exhibit a transition from a non-linear to a linear regime. In the linear regime, the edges and corners of the flat-neeedle shaped crystals are often determined by diffusion. Due to the high anisotropy of fat crystals, the morphologically unstable patterns observed above the transition, appear as non-faceted or faceted dagger-like shapes, depending whether the top faces are kinetically roughened or not. For tripalmitate grown from trioleate, flat faces are still observed above the transition, despite completely linear kinetics. Only at even larger supersaturation these crystal faces become unstable, showing that flat faces can still be obtained under diffusion limited conditions.     

Polymorphism and Mixing Phase Behavior in Ternary Mixture Systems of SOS–SSO–OSO: Formation of Molecular Compound Crystals

This paper reports the phase behavior of ternary mixtures of saturated and cis‐monounsaturated mixed‐acid triacylglycerols (TAG) of SOS (1,3‐distearoyl‐2‐oleoyl‐glycerol), SSO (1,2‐distearoyl‐3‐oleoyl‐rac‐glycerol), and OSO (1,3‐dioleoyl‐2‐stearoyl‐glycerol) examined with X‐ray diffractometry and a differential scanning calorimeter. The ternary mixtures were crystallized by cooling from melt (60 °C) to 5 °C, and the crystals were then stabilized by storing the mixture samples at 28 °C for 10 days. The following results were obtained. (1) Molecular compound (MC) crystals of stable β polymorph having a double‐chain‐length structure (β‐2) were formed in mixtures of SOS/SSO/OSO in which the concentration of SOS was 50% with varying concentrations of SSO/OSO. This is in contrast to the fact that the stable polymorphic forms of the component TAG are β‐3 for SOS and OSO and β′‐3 for SSO. (2) When the concentration of SOS deviated from 50%, immiscible mixtures of β‐2 MC made of SOS/SSO/OSO and the component TAG (β‐3 of SOS and OSO and β′‐3 of SSO) were formed. Therefore, ternary mixtures of SOS/(SSO + OSO) = 50/50 with different concentrations of SSO and OSO are miscible mixtures of β‐2 of SOS/SSO and SOS/OSO.     

Acute Fasting Induces Expression of Acylglycerophosphate Acyltransferase (AGPAT) Enzymes in Murine Liver,Heart, and Brain

During fasting, cells increase uptake of non-esterified fatty acids (NEFA) and esterify excess into phosphatidic acid (PtdOH), the common precursor of both triacylglycerols and phospholipids, using acylglycerophosphate acyltransferases/lysophosphatidic acid acyltransferases (AGPAT/LPAAT). Knowledge of the regulation of AGPAT enzymes is important for understanding fasting adaptations. Total RNA was isolated from liver, heart, and whole brain tissue of C57BL/6J mice fed ad libitum, or fasted for 16 h. Following fasting, induction of Agpat2, 3, 4, and 5 was observed in the liver, Agpat2 and 3 in heart tissue, and Agpat1, 2, and 3 in whole brain tissue. As a result, the relative abundance profile of the individual homologues within specific tissues was found to be significantly altered depending on the nutritive state of the animal. These data demonstrate tissue-specific effects of fasting on the regulation of different Agpat that are implicated in supporting unique downstream glycerolipid synthesis pathways.     

Fingerprinting Krill Oil by 31P, 1H and 13C NMR Spectroscopies

The detailed analysis of krill oil is of importance to be able to differentiate other oils, identify adulterated products, and provide the highest quality associated with its beneficial health effects. The objective of this study was to demonstrate the usefulness of the combination of ³¹P, ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopies to characterize the krill oil profile. It was found that in contrast to fish oil, where eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) fatty acids are found in triacylglycerol, krill oil is characterized by a more asymmetric fatty acid distribution with a higher polyunsaturated fatty acids PUFA content in the sn‐2 position of phospholipids and lower amounts in triacylglycerol. Besides the typical asymmetric fatty acid composition, several other markers were investigated for krill oil origin test. The validation of the ³¹P NMR spectroscopic method regarding major phospholipid species was performed according to the Good Laboratory Practice (GLP) and International Council for Harmonisation (ICH) guidelines. The method was characterized by high sensitivity, accuracy, and reproducibility. Interlaboratory testing showed satisfactory robustness regardless of the type of NMR equipment used by different laboratories. High‐resolution NMR spectroscopy has proven to be a convenient and exact method for providing a characteristic fingerprint of krill oil. By this technique, clear distinctions to other oils can be made through qualitative and quantitative analysis of krill oil.     

Emission of Volatile Aldehydes from DAG-Rich and TAG-Rich Oils with Different Degrees of Unsaturation During Deep-Frying

The purpose of the present study was to compare the emission of volatile aldehydes from diacylglycerol-rich oils (DAG-OILs) and triacylglycerol-rich oils (TAG-OILs) with different degrees of unsaturation of fatty acid moieties during the deep-frying of sliced potatoes. To examine the effect of fatty acid composition, four kinds of oils with different fatty acid compositions were selected: rape seed (RS); sunflower oil as a high oleic (HO); safflower oil as high linoleic (HL); and, perilla oil as high linolenic (HLn) oils. The emissions of volatile aldehydes were determined during the deep-frying of sliced potatoes by using the above fresh test oils or deteriorated RS oils. The statistical analysis showed no significant difference in volatile aldehyde emission and profile between the DAG-OIL and TAG-OIL with the fatty acid composition of RS, HL, and HLn. Although a statistically significant difference was noted in the volatile aldehyde emission between the DAG-OIL and TAG-OIL with HO, this difference was extremely small when compared to the variations found in the oils with four types of fatty acid composition. Finally, no difference was found in the volatile aldehyde emissions between the deteriorated DAG-OIL and TAG-OIL, although volatile aldehyde emissions increased with frying time. In addition, the acrylamide contents in potato chips prepared with RS–DAG or RS–TAG were at comparable levels.