Triacylglycerol Molecules Research Articles

Assessment of the Stability and Nutritional Quality of Hemp Oil and Pumpkin Seed Oil Blends.

This study characterized the quality of hemp oil (HO) and pumpkin seed oil (PO) and their blends before and after 2 and 4 months of storage at refrigerated and room temperature, without access to light and oxygen. The analyses included determining the acid value, peroxide value, fatty acid (FA) composition, and FA distribution in triacylglycerol (TAG) molecules. Pressure differential scanning calorimetry (PDSC) was used to assess the oxidative stability of oils and their blends. This study also evaluated the nutritional potential of hemp oil and pumpkin seed oil blends, as atherogenicity, thrombogenicity, and health-promoting indices and hypocholesterolaemic/hypercholesterolaemic ratio were calculated. The tested samples differed in properties depending on the storage time and temperature. The optimal choice was a blend of 50% hemp oil (HO) and 50% pumpkin oil (PO). This mixture demonstrated the desired fatty acid composition, satisfactory acid and peroxide values, and a relatively good oxidation induction time during storage. Despite the unfavorable distribution of FAs in TAG molecules, it was characterized by a balanced ratio of n-3 to n-6 acids. It was also concluded that research on HO and PO mixtures should be continued due to the potential synergistic effect of their bioactive substances.

Burn your fat—a unique DIY board game about triacylglycerol breakdown

Understanding metabolic pathways is challenging for students due to their complex nature and intricate interdependencies. To address this problem, gamification has emerged as a promising approach to make scientific concepts accessible and engaging. We present a DIY educational activity focusing on lipid and glucose metabolism to clarify the basic principles of biochemical transformations and provide practical educational resources for lecturers. The activity is designed to be accessible and requires minimal resources, using physical media such as printed boards and dice. It consists of two parts: an introductory session where students build a triacylglycerol molecule and a board game where teams compete to metabolically break down triacylglycerols and obtain ATP. The process in governed by rules based on metabolic transformations, with players taking on roles as walkers, counters, transformers, and strategists to encourage cooperation. The game aligns with the theories of cognitivism and constructivism and emphasizes knowledge acquisition, the formation of mental structures, and active learning through experience. It promotes a socio-cultural perspective and the development of interpersonal skills by encouraging teamwork, cooperation, and problem-solving. The thematic focus on obesity provides real-world context, and the DIY concept, 3D printing capability, and potential for creating extensions encourage student engagement and customization. The activity effectively teaches metabolic networks to high school students, is helpful for graduate students in visualizing experimental problems, increased engagement in the classroom and interest in the life sciences. A simplified version has also been used for the general public at science fairs, highlighting its versatility and accessibility.

Prediction of melting and solid phase transitions temperatures and enthalpies for triacylglycerols using artificial neural networks

Triacylglycerols (TAG) are the main components of vegetable oils and any attempt to simulate vegetable oils processes will demand knowledge of their properties. However, experimental values are scarce, considering that several TAG in their pure forms are unavailable or too expensive for experimental measurements. On the other hand, correlating physical properties with TAG molecular structure is not simple. TAG is a molecule composed of 3 fatty acids (FA) esterified to a glycerol (GL) backbone, making properties dependent on carbon number (CN) of each FA, number of unsaturations (UN) of each FA, and position of the FA in the GL backbone. Few models are available in literature for prediction of TAG melting properties, with a special attention to melting temperature (Tfus) and enthalpy (ΔHfus) and solid-solid transition properties of the TAG polymorphic forms. Wesdorp's, Moorthy's et al. and Zeberg-Mikkelsen and Stenby's works present models based on the Group-Contribution theory nowadays used, despite some flaws, particularly considering the polymorphic transitions. Therefore, this work was aimed at evaluating Artificial Neural Network (ANN) models for prediction of TAG's Tfus and ΔHfus (β-form) as well as temperature and enthalpy transitions of molecule polymorphic forms (α and β’). Database was composed of temperature and enthalpy experimental data from literature. For each TAG, 7 input data were provided: total CN, as well as CN and UN at sn-1, 2 and 3 TAG position. The Multilayer Perceptron Feed Forward (MPL) model was used, and the topology was evaluated for number of hidden layers (HL), number of neurons (NN) and activation function at each hidden layer, and convergence algorithm. Number of HL and NN was screened by using a Central Composite Rotatable Design (CCRD). Models were further evaluated by Explainable Artificial Intelligence (XAI) and feature evaluation strategies. Architectures showed a significant higher accuracy for calculation and prediction of TAG's melting properties of the 3 polymorphic forms, with R2 higher to 0.91 for all databases when compared to literatures’ models (excepted for the prediction of the melting temperature of the β form, where Wesdorp's model presented a better predictive ability, despite great similarity). Good results were probably related to the well-defined physicochemical relationship between input (molecular structure descriptors) and output (melting properties), that could be described by XAI evaluation. This is an important advantage considering the improvement of the performance of process and products design including TAG molecules.

The Influence of Feeding Type on Quality and Nutritional Characteristics of Pork Fat

The purpose of the study was to analyze the effect of feeding type on selected quality parameters and the nutritional characteristics of pork fat. Fats were extracted by using the modified Folch method from the groin, jowl and trimming shoulder of pigs fed two types of diets: liquid and dry. The peroxide values and fatty acid profiles, as well as their distribution, in the triacylglycerol molecules were determined. Additionally, nutritional indexes and thermal properties, including the oxidative stability of pork fat, were assessed. Among the tested fats, the groin fat was characterized by the best oxidative stability which did not depend on the diet type used. In the case of jowl and trimming shoulder, a higher share of monounsaturated fatty acids was determined in fats of pigs fed a liquid diet, whereas in the groin, jowl and trimming shoulder fats of pigs fed dry feed, a higher share of polyunsaturated fatty acids was found. Fats extracted from the groin, jowl and trimming shoulder of pigs fed a liquid diet showed a more favorable ratio of n-6 to n-3 acids. Despite the different feeding systems used, tested fats were characterized by a similar distribution of fatty acids in triacylglycerol molecules with a positive effect on fat digestibility. It is worth emphasizing that especially in the case of trimming shoulder fat, the influence of a diet used in pigs’ nutrition on quality parameters was noticeable. The trimming shoulder fat of pigs fed a liquid diet was characterized by a longer induction time of oxidation, contained less saturated fatty acids and presented a more favorable fatty acid profile with a beneficial distribution of fatty acids in triacylglycerol molecules.

Enzymatic synthesis of structured lipids rich in α‐linolenic acid: impacts of triacylglycerol profile on physicochemical characteristics

SummaryMedium‐ and long‐chain triacylglycerols rich in α‐linolenic acid (ALA‐MLCT) are a kind of functional structural lipids that provide ω‐3 fatty acid and faster energy supply to human body. To improve the functional and nutritional properties of vegetable oils, we proposed an effective strategy for the synthesis of ALA‐MLCT by enzymatic interesterification of coconut oil and flaxseed oil. Lipase UM1 exhibited the highest interesterification activity compared with commercial Lipozyme RM IM, Lipozyme TL IM and Novozym 435. MLCT (76.59%) and ALA‐MLCT (45.03%) were obtained under the optimum reaction conditions: substrate molar ratio (coconut oil/flaxseed oil) 1:1, temperature 40 °C, Lipase UM1 loading 25 U g‑1. Furthermore, we identified 14 characteristic triacylglycerols molecules between enzymatic interesterification and physical blend by orthogonal partial least squares‐discrimination analysis (OPLS‐DA) model. The content of triunsaturated type triacylglycerols in enzymatic interesterification product (11.29%) was lower than that of physical blend (36.25%). Enzymatic interesterification product had lower solid fat content and 2.44 times oxidative stability than physical blend. These findings provide an effective strategy for the synthesis of functional ALA‐MLCT and advance the understanding of the relationship between triacylglycerols composition and physicochemical characteristics.

Determination of Triacylglycerol Composition in Mealworm Oil (Tenebrio molitor) via Electrospray Ionization Tandem Mass Spectrometry with Multiple Neutral Loss Scans.

Mealworms (Tenebrio molitor) have been used as an alternative source of proteins and lipids. Triacylglycerols (TAGs) are major sources of energy and have been used to provide essential fatty acids. They are also the main components of mealworm oil, and their composition and content are extensively linked to its physical and chemical properties. However, because of the complexity of TAG molecules, their identification and quantitation are challenging. This study employed electrospray ionization tandem mass spectrometry (ESI-MS/MS) with multiple neutral loss scans (NLS) to analyze the TAG composition and content in mealworm oil. Identifying and quantifying TAGs using ESI-MS/MS in combination with multiple NLS was an efficient way to improve accuracy and timeliness. For the accurate quantification of TAGs, isotopic deconvolution and correlation factors were applied. A total of 57 TAGs were identified and quantified: C52:2 (16:0/18:1/18:1) (1549.4 nmol/g, 18.20%), C52:3 (16:0/18:1/18:2) (1488.1 nmol/g, 17.48%), C54:4 (18:1/18:1/18:2) (870.1 nmol/g, 10.23%), C54:6 (18:1/18:2/18:2) (659.8 nmol/g, 7.76%) and C52:4 (16:0/18:2/18:2) (600.5 nmol/g, 7.06%), which were the most abundant TAGs present in the mealworm oil. The fundamental properties of mealworm oil, including its degree of oxidation, nutritional effect and physical properties, were elucidated.

CHARMM-GUI Membrane Builder for Lipid Droplet Modeling and Simulation.

Lipid droplets (LDs) are organelles that are necessary for eukaryotic and prokaryotic metabolism and energy storage. They have a unique structure consisting of a spherical phospholipid monolayer encasing neutral lipids such as triacylglycerol (TAG). LDs have garnered increased interest for their implications in disease and for drug delivery applications. Consequently, there is an increased need for tools to study their structure, composition, and dynamics in biological contexts. In this work, we utilize CHARMM-GUI Membrane Builder to simulate and analyze LDs with and without a plant LD protein, oleosin. The results show that Membrane Builder can generate biologically relevant all-atom LD systems with relatively short equilibration times using a new TAG library having optimized headgroup parameters. TAG molecules originally inserted into a lipid bilayer aggregate in the membrane center, forming a TAG-only core flanked by two monolayers. The TAG-only core thickness stably grows with increasing TAG mole fraction. A 70 % TAG system has a core that is thick enough to house oleosin without its interactions with the distal leaflet or disruption of its secondary structure. We hope that Membrane Builder can aid in the future study of LD systems, including their structure and dynamics with and without proteins.

The step-by-step assembly mechanism of secreted flavivirus NS1 tetramer and hexamer captured at atomic resolution.

Flaviviruses encode a conserved, membrane-associated nonstructural protein 1 (NS1) with replication and immune evasion functions. The current knowledge of secreted NS1 (sNS1) oligomers is based on several low-resolution structures, thus hindering the development of drugs and vaccines against flaviviruses. Here, we revealed that recombinant sNS1 from flaviviruses exists in a dynamic equilibrium of dimer-tetramer-hexamer states. Two DENV4 hexameric NS1 structures and several tetrameric NS1 structures from multiple flaviviruses were solved at atomic resolution by cryo-EM. The stacking of the tetrameric NS1 and hexameric NS1 is facilitated by the hydrophobic β-roll and connector domains. Additionally, a triacylglycerol molecule located within the central cavity may play a role in stabilizing the hexamer. Based on differentiated interactions between the dimeric NS1, two distinct hexamer models (head-to-head and side-to-side hexamer) and the step-by-step assembly mechanisms of NS1 dimer into hexamer were proposed. We believe that our study sheds light on the understanding of the NS1 oligomerization and contributes to NS1-based therapies.

Internal Factors Affecting the Crystallization of the Lipid System: Triacylglycerol Structure, Composition, and Minor Components.

The process of lipid crystallization influences the characteristics of lipid. By changing the chemical composition of the lipid system, the crystallization behavior could be controlled. This review elucidates the internal factors affecting lipid crystallization, including triacylglycerol (TAG) structure, TAG composition, and minor components. The influence of these factors on the TAG crystal polymorphic form, nanostructure, microstructure, and physical properties is discussed. The interplay of these factors collectively influences crystallization across various scales. Variations in fatty acid chain length, double bonds, and branching, along with their arrangement on the glycerol backbone, dictate molecular interactions within and between TAG molecules. High-melting-point TAG dominates crystallization, while liquid oil hinders the process but facilitates polymorphic transitions. Unique molecular interactions arise from specific TAG combinations, yielding molecular compounds with distinctive properties. Nanoscale crystallization is significantly impacted by liquid oil and minor components. The interaction between the TAG and minor components determines the influence of minor components on the crystallization process. In addition, future perspectives on better design and control of lipid crystallization are also presented.

Heterologous phospholipid:diacylglycerol acyltransferase channels eicosapentaenoic acid to triacylglycerol in Phaeodactylum tricornutum

Phaeodactylum tricornutum is a well-studied oleaginous model diatom with high triacylglycerol (TAG) and omega-3 eicosapentaenoic acid (EPA) contents, however, only a small portion of EPA is transferred from the polar lipids to TAG through phospholipid:diacylglycerol acyltransferase (PDAT). In this study, a Nannochloropsis oceanica PDAT (NoPDAT) was heterologously expressed in P. tricornutum to increase the EPA content in TAG. NoPDAT heterologous expression slightly disturbed the growth of the transgenic lines, but enhanced the TAG content by 16–18 %. Considering the localization of NoPDAT in P. tricornutum after heterologous expression together with our lipidomic results, NoPDAT is more likely to utilize phosphatidylcholine and phosphatidylethanolamine on the chloroplast endoplasmic reticulum membrane as the acyl donors. Especially, NoPDAT transferred the EPA acyl moiety from the sn-2 position of the two above-mentioned phospholipids to the sn-3 position of TAG, resulting in the increase of two major EPA-containing TAG molecules (16:1/16:0/20:5 and 16:1/16:1/20:5). Correspondingly, two major 16:0-containing TAG molecules (16,0/16:1/16:1 and 16:0/16:0/16:1) decreased in the transgenic strains. In conclusion, our attempt to express NoPDAT in P. tricornutum increases the EPA content in TAG by approximately one-fold, and demonstrates the versatility of diatom lipid metabolism and acyl editing.

Chemical compositions and crystallization characteristics of SOS‐rich fats

AbstractSOS‐rich fats have been developed to improve heat stable properties and fat bloom‐resistant abilities of chocolates, which is highly connected with their crystallization behaviors. Shea butter stearin (SBS) and mango kernel fat (MKF) are the typical SOS‐rich fats. Both contained high levels of stearic acid (45.06%–59.67%) and oleic acid (31.85%–39.97%), while 77.00%–86.88% of the oleic acid were distributed at the sn‐2 positions of triacylglycerol molecules, contributing to forming 78.04% of SOS in SBS and 47.85% of SOS in MKF. Their SOS levels were significantly higher than that in cocoa butter (CB, 25.43%). However, MKF contained the highest levels of SOO (15.59%), which was about six to eight times as likely that in SBS and CB (1.76%–2.66%). Further crystallization tests revealed that SBS and MKF exhibited similar rod‐like growth from instantaneous nuclei at 4°C. The former was then changed to become more spherulitic growth at 20°C significantly. Specifically, large feather‐like crystals corresponding to β form were observed in SBS at the final stage of crystallization at 20 and 30°C, while MKF exhibited smaller crystals. The higher concentration of SOO in MKF was considered as the softening factor. It was further supposed that constant crystallization at 20°C may be difficult for some fats (e.g., SOS < 30%) to form adequate amounts of β crystals. The results will provide information on making cocoa butter blends and chocolate tempering.

Assessment of the Nutritional Potential and Resistance to Oxidation of Sea Buckthorn and Rosehip Oils

Cold-pressed oils from non-typical materials, such as wild rose and sea buckthorn, should meet certain requirements to be approved for consumption. The aim of this study was to evaluate the nutritional potential and selected quality parameters with particular emphasis on oxidative stability of two commercially available cold-pressed oils: rose hip oil and sea buckthorn oil. The fatty acid composition, including nutritional indexes (polyunsaturated fatty acid/saturated fatty acid ratio PUFA/SFA; atherogenicity index IA is as follows: hypocholesterolemic/hypercholesterolemic index HH; health-promoting index HPI), positional distribution of fatty acids, melting profile and oxidative stability were analyzed. The tested oils were characterized by a high content of unsaturated fatty acids, which were mainly represented by oleic and linoleic acids. In the case of one of the analyzed rosehip oil oils (R1), α-linolenic acid was also found at the level of 26%, which contributed to obtaining the recommended ratio of omega-6 to omega-3 fatty acids. The lowest value of IA and the highest values of HH and HPI were also recorded for R1 rosehip oil. This oil was also characterized by the highest resistance to oxidation, as indicated by induction times measured at various temperatures. The distribution of fatty acids in triacylglycerols molecules in the analyzed oils was typical for vegetable oils. In the case of tested oils, similar melting profiles with endothermic peaks recorded at negative temperatures, which resulted from the presence of triacylglycerol fractions with a high proportion of mono- and polyunsaturated fatty acids, were observed.

On the clustering of triacylglycerols in the molten state

The liquid–solid phase transition of triacylglycerols (TAGs), the main components of edible fats and oils is central to the production and sensory properties of many processed foods. While there has been extensive research on the nucleation and growth of fats, there remains a dearth of knowledge regarding the structural organization of TAGs in the liquid state. From a molecular perspective, TAGs consist of three alkyl chains esterified to a glycerol backbone. Several models based on experiment and simulation have helped to unveil TAG organization in the molten state. However, more evidence for their structural organization is necessary. Here, we provide simulation and experimental insights on the structural organization of molten tripalmitin using small-angle neutron and x-ray scattering, and wide-angle x-ray scattering. In agreement with recent work, we also propose a model in which TAGs associate as clusters via glycerol-glycerol interactions, with their alkyl chains extending outwards in a loose shell. Our model, however, highlights and demonstrates the dynamic nature of clusters, where TAGs can transfer from one cluster to another via diffusion. The average number of TAG molecules per cluster varies from 5 to 9 and decreases with increasing temperature, which results in a smaller average distance between clusters. Overall, this study strongly suggests that prior to the onset of nucleation, TAGs are associated as dynamic clusters formed via intermolecular interactions between neighboring glycerol cores.

Medium- and Long-Chain Triacylglycerol: Preparation, Health Benefits, and Food Utilization.

Medium- and long-chain triacylglycerol (MLCT) is a structured lipid with both medium- and long-chain fatty acids in one triacylglycerol molecule. Compared with long-chain triacylglycerol (LCT), which is mainly present in common edible oils, and the physical blend of medium-chain triacylglycerol with LCT (MCT/LCT), MLCT has different physicochemical properties, metabolic characteristics, and nutritional values. In this article, the recent advances in the use of MLCT in food formulations are reviewed. The natural sources and preparation of MLCT are discussed. A comprehensive summary of MLCT digestion, absorption, transport, and oxidation is provided as well as its health benefits, including reducing the risk of overweight, hypolipidemic and hypoglycemic effects, etc. The potential MLCT uses in food formulations, such as infant formulas, healthy foods for weight loss, and sports foods, are summarized. Finally, the current safety assessment and regulatory status of MLCT in food formulations are reviewed.

Lipidomics reveals the relationship between lipid oxidation and flavor formation of basic amnio acids participated Low-Sodium cured large yellow croaker.

The effects of basic amino acids on lipid oxidation and the formation of volatile compound in low-sodium cured large yellow croaker were investigated. Basic amino acids contribute a lot in inhibiting the degradation of phospholipids, especially l-lysine. Lipid oxidation was also inhibited by basic amino acids, and the total oxidation of groups could be sorted as low-sodium (LS)>control (C)>l-Histidine participated LS group (LS-His)>l-Arginine participated LS group (LS-Arg)>l-lysine participated LS group (LS-Lys). PC 18:1/20:5, PC 16:0/18:1, triacylglycerol (TG) 16:1/20:5/22:6, etc., were found to be key differential lipid metabolites, and 1-propanol, 2-methyl, gamma-hexalactone, etc. were recognized as key differential volatile compounds. The results of correlation analysis showed that alcohols and esters were positively correlated with TG molecules composed of saturated fatty acids and monounsaturated fatty acids. These findings provided new insights into the relationship between flavor formation and the degradation and oxidation of lipids.

Stearic acid promotes lipid synthesis through CD36/Fyn/FAK/mTORC1 axis in bovine mammary epithelial cells

Stearic acid (C18:0, SA) is a saturated long-chain fatty acid (LCFA) that has a prominent function in lactating dairy cows. It is obtained primarily from the diet and is stored in the form of triacylglycerol (TAG) molecules. The transmembrane glycoprotein cluster of differentiation 36 (CD36) is also known as fatty acid translocase, but whether SA promotes lipid synthesis through CD36 and FAK/mTORC1 signaling is unknown. In this study, we examined the function and mechanism of CD36-mediated SA-induced lipid synthesis in bovine mammary epithelial cells (BMECs). SA-enriched supplements enhanced lipid synthesis and the FAK/mTORC1 pathway in BMECs. SA-induced lipid synthesis, FAK/mTORC1 signaling, and the expression of lipogenic genes were impaired by anti-CD36 and the CD36-specific inhibitor SSO, whereas overexpression of CD36 effected the opposite results. Inhibition of FAK/mTORC1 by TAE226/Rapamycin attenuated SA-induced TAG synthesis, inactivated FAK/mTORC1 signaling, and downregulated the lipogenic genes PPARG, CD36, ACSL1, SCD, GPAT4, LIPIN1, and DGAT1 at the mRNA and protein levels in BMECs. By coimmunoprecipitation and yeast two-hybrid screen, CD36 interacted directly with Fyn but not Lyn, and Fyn bound directly to FAK; FAK also interacted directly with TSC2. CD36 linked FAK through Fyn, and FAK coupled mTORC1 through TSC2 to form the CD36/Fyn/FAK/mTORC1 signaling axis. Thus, stearic acid promotes lipogenesis through CD36 and Fyn/FAK/mTORC1 signaling in BMECs. Our findings provide novel insights into the underlying molecular mechanisms by which LCFA supplements promote lipid synthesis in BMECs.

Defining the physical properties of blends of acetyl‐triacylglycerols derived from transgenic oil seeds

AbstractAcetyl‐TAG are unusually structured triacylglycerols (TAG) that possess an acetate group at their sn‐3 position. Acetyl‐TAG have different physical properties compared to regular TAG, including lower viscosity and improved cold temperature properties, making acetyl‐TAG useful for different applications, including as a diesel replacement. These unusual TAG molecules can be synthesized in the seeds of transgenic plants through the expression of diacylglycerol acetyltransferase (DAcT) enzymes isolated from different Euonymus species. In this study, the kinematic viscosity as well as the crystallization and melting behavior of blends of acetyl‐TAG and regular TAG were examined to define goals for acetyl‐TAG synthesis in transgenic plants. Even small amounts of regular TAG when blended with acetyl‐TAG had a disproportionate effect on the viscosity of mixture. This effect of regular TAG in increasing kinematic viscosity was more pronounced at lower temperatures. Under slow cooling conditions, the two different TAGs and their blends possessed two main crystallization events with different degree of separation of the thermal transition, and the lower crystallization temperature decreased with increasing amounts of acetyl‐TAG in the blend. At higher cooling rates, one broad and tailed crystallization peak was observed. Heating thermograms indicate similar polymorphic behavior of the blends and a general peak shift to lower transition range with increasing acetyl‐TAG compared to the two pure lipids. This information about the viscosity and thermal properties of blends of TAG and acetyl‐TAG will provide useful targets for engineering higher levels of acetyl‐TAG in transgenic seeds.

Mixing phase behavior of trilaurin and monounsaturated triacylglycerols based on palmitic and oleic fatty acids

Differential scanning calorimetry and X-ray diffraction were used to examine the mixing phase behavior of LLL (trilaurin or 1,2,3-trilauroyl-glycerol) and POP (1,3-dipalmitoyl-2-oleoyl-glycerol), PPO (1,2-dipalmitoyl-3-oleoyl-rac-glycerol), or the 50POP/50PPO blend able to form a molecular compound. This research aims to provide an insight into the molecular interactions ruling the physical behavior of fat blends of lauric (i.e., coconut oil) and non-lauric lipids (cocoa butter, palm oil, etc.). The results showed eutectic behavior and no mutual solubility of triacylglycerols in stable LLL/POP and LLL/PPO mixtures. Applying high-rate cooling treatments had a positive effect on miscibility, but the high incompatibility of the components due to differences in length and degree of unsaturation of fatty acids was still evident in metastable polymorphs. In ternary LLL/(50POP/50PPO) mixtures, on the other hand, molecular compound β-2L crystals formed by POP and PPO showed to favor the solubility of LLL as compared to the binary systems. Accordingly, promoting the presence of triacylglycerols forming molecular compound in specific fat blends may help reducing eutectic or incompatible interactions among triacylglycerol molecules in the solid state. These lead to phase separation and are a major cause of the restricted applicability of lauric oils in the confectionery and chocolate industries.

Effects of Cooling Rate and Emulsifier Combination on the Colloidal Stability of Crystalline Dispersions Stabilized by Phospholipids and β-Lactoglobulin

A lot of applications for (semi-)crystalline triacylglycerol (TAG)-in-water dispersions exist in the life science and pharmaceutical industries. Unfortunately, during storage, these dispersions are often prone to changes in particle size due to unforeseen crystallization and recrystallization events. This results in the alterations of important product properties, such as viscosity and mouthfeel, or the premature release of encapsulated material. In this study, we investigated the effects and interplay of formulation, i.e., emulsifier combination, and processing parameters, i.e., cooling rate, on the colloidal stability of dispersed TAGs and aimed to improve their colloidal stability. We chose phospholipids (PLs) and β-lactoglobulin (β-lg) as the emulsifiers for our model systems, which are commonly applied in many food systems. When dispersions were characterized directly after cooling, we obtained smaller particles and narrower size distributions after fast cooling. Over the course of eleven weeks, the creaming behavior, particle size, melting behavior and polymorphism were characterized. The dispersions stabilized with solely β-lg exhibited a slight increase in particle size, whereas a decrease in size was found when PLs were added. Our results indicate that mass transport phenomena between TAG droplets and particles took place during storage. This migration of TAG molecules changed the composition and size distribution of the dispersed phase, especially at higher PL concentration (0.1 wt%). In our case, this could be prevented by using a lower concentration of PLs, i.e., 0.05 wt%.

Evaluation the selectivity of three lipases in the synthesis of 1-oleoyl-2-palmitoyl-3-linoleoylglycerol, an asymmetric triacylglycerol

1-Oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) is the most abundant triacylglycerol (TAG) molecule in Chinese human milk. The selectivity of three lipases including Rhizomucor miehei lipase (RML), Thermomyces lanuginose lipase (TL), and Candida antarctica lipase (CALB) in OPL synthesis were evaluated. The effects of different reaction conditions on selectivity were first investigated. Unexpectedly, the three sn-1,3 regioselectivity lipases, also have selectivity for the structure of product TAGs. Compared with symmetric TAGs, lipases had poor selectivity toward asymmetric OPL. Furthermore, molecular simulations were used to deeply understand the molecular factors affecting lipase selectivity. The results showed that hydrophobic interactions, lipases lid domain flexibility, and the stability of hydrogen bonds between lipases and TAGs were the main molecular factors responsible for the selectivity of lipases.