Mixtures Of Triacylglycerols Research Articles

Modeling of enzymatic transesterification for omega-3 fatty acids enrichment in fish oil

Mathematical models of transesterification commonly assume that oil is a mixture of triacylglycerols, where each component has only one type of acid attached. This article aims to show how a different assumption on acid distribution affects the results of acylglycerols fraction composition. Experiments of fish oil ethanolysis have been performed at different enzyme loadings and ethanol concentrations, leading to enrichments from 35 % to 52 % of ω3 mass fraction in acylglycerols, by losing 12.1 % of ω3 as ethyl esters. A kinetic model is developed assuming both all acids of the same type on each acylglycerol and all acids randomly distributed on the available positions. The two different assumptions showed strong discrepancies on the acylglycerols fraction compositions predictions, demonstrating how the initial fatty acids distribution is important when an accurate description of the acylglycerols fraction is desired.

Kinetic Phase Behavior of Binary Mixtures of Tri-Saturated Triacylglycerols Containing Lauric Acid

Kinetic Phase Behavior of Binary Mixtures of Tri-Saturated Triacylglycerols Containing Lauric Acid

How triacylglycerol thermal history impacts film removal by surfactant solution

Hypothesis: The physical and mechanical properties of triacylglycerols (TAGs), or ‘fats’, depend on their composition and thermal history which, in turn, impact crystal structure and morphology. We examine whether thermal history can be mechanistically related to film removal by a surfactant solution.Experiments: Model TAG mixtures, comprising triolein:tripalmitin:tristearin 0.5:0.3:0.2, were subjected to a range of cooling profiles from the melt (0.5-80°C/min, Newtonian and annealed), and the resulting solid films characterised by microscopy, X-ray diffraction, infrared spectroscopy, and contact angle measurements. Film removal from a model glass substrate by an aqueous surfactant solution of sodium dodecylsulphate and dodecyldimethylamine oxide at room temperature fixed at 25°C was examined under quiescent flow conditions.Findings: Quantitative relations are established between TAG cooling profile, crystal structure and morphology, surface energy γSFE, and removal (or ‘cleaning’). In general, films cooled slowly from the melt yield heterogeneous morphologies with predominantly β1′ phase, higher polar γSFE, and faster removal timescales. By contrast, rapid cooling results in homogeneous films, rich in β2′ phase, low polar γSFE, and long removal times. Our results elucidate the non-trivial impact of TAG thermal history, connecting the multiscale semi-crystalline structure to surface energy, and eventually to film delamination by micellar solutions.

Formation mechanisms of molecular compound in saturated‐unsaturated mixed‐acid triacylglycerols mixture systems and its edible applications

AbstractThe triacylglycerols (TAGs) containing saturated (Sat)‐unsaturated (U) fatty acid moieties (Sat‐U mixed acid TAGs) are widely present in most natural fats and employed in many industrial applications. The mixing behavior of different Sat‐U mixed acid TAGs acts important roles in the physicochemical properties TAG‐based materials. Among the three main mixing states of miscible, eutectic and molecular compound (MC) forming mixtures, fundamental research has been conducted on the MC crystals formed by different Sat‐U mixed acid TAGs to understand the structures, phase behavior and crystallization properties. This article reviews studies to date on the complex thermodynamic, kinetic and structural factors that affect the formation of MC crystals in binary and ternary mixtures of Sat‐U mixed acid TAGs (SatUSat, SatSatU, USatU and UUSat) through specific molecular interactions among the component TAGs. Furthermore, the application of the MC‐forming mixtures containing cacao butter to new types of cocoa butter alternative is reviewed.

Solid-liquid equilibria of triacylglycerols and vitamin E mixtures

Oils and fats are important ingredients for food and pharmaceutical industries. Their main compounds, such as triacylglycerols (TAG), are responsible for determining their physical properties during food storage and consumption. Lipid-rich foods are also sources of minority compounds, which is the case of vitamin E, mainly represented by (±)-α-tocopherol. These compounds can interact with the main lipid molecules in food formulation leading to modification on lipids’ physicochemical properties during processes, storage, as well as during digestion, possibly altering their nutritional functionalities, which is the case of vitamin E antioxidant abilities, but also their solubility in the systems. In this case, the study of the phase-behavior between (±)-α-tocopherol and lipid compounds can elucidate these physicochemical changings. Therefore, this work was aimed at determining the solid–liquid equilibrium (SLE) of binary mixtures of TAG (tripalmitin, triolein and tristearin) and (±)-α-tocopherol including the complete description of their phase diagrams. Melting data were evaluated by Differential Scanning Calorimetry, Microscopy, X-Ray Diffraction, and thermodynamic modeling by using Margules, UNIFAC, and COSMO-SAC models. Experimental results showed that systems presented a monotectic-like behavior, with a significant decreasing in TAG melting temperature by the addition of (±)-α-tocopherol. This high affinity and attractive strengths between these molecules were also observed by thermodynamic modeling, whose absolute deviations were below 2 %. Micrographs and X-ray diffraction evidenced the possible formation of solid solutions. Both behaviors are interesting by avoiding phase separation on food in solid and liquid phases, possibly improving the antioxidant role the (±)-α-tocopherol in lipid-base systems.

Impact of column temperature on triacylglycerol regioisomers separation in silver ion liquid chromatography using heptane-based mobile phases

This work presents the investigation of the use of heptane as an alternative and less toxic mobile phase to the most used hexane for triacylglycerols (TAGs) analysis in silver ion high-performance liquid chromatography (Ag+-HPLC). The impact of column temperature (in the 5 °C-35 °C range) on the retention and resolution of five pairs of regioisomers relevant for the confectionery industry was investigated using a heptane-based mobile phase modified with acetonitrile (ACN). The retention behaviour was compared for a standard TAG mixture and an interesterified cocoa butter. The temperature effect previously observed with hexane-based mobile phases was confirmed for this new system, and it was also observed that the ACN concentration had an important impact on the strength of the temperature effect, with a higher ACN concentration leading to a lesser impact of temperature on the TAGs’ elution behaviour. In general, the study allowed to conclude on the equivalence of hexane and heptane for TAGs regioisomers separation in Ag+-HPLC, independently of the used temperature or the ACN concentration. In addition, the applicability of heptane-based mobile phases for the separation of TAGs regioisomers was demonstrated on three other confectionary fat samples, namely palm olein, interesterified palm olein, and interesterified shea olein.

In-Depth Chemical Characterization of Punica granatum L. Seed Oil.

Fruit seeds belonging to the pomegranate cultivar "Granata" were subjected to extraction and oily component analysis, with the aim of obtaining information about their composition. The presence of conjugated isomers of linolenic acid (CLNA isomers) in the oily phase extracted from the seeds gives a high added value to this part of the fruit, which is too often considered and treated as waste. The separated seeds were subjected to a classic Soxhlet extraction with n-hexane or extraction with supercritical CO2, assisted by ethanol. The resulting oils were evaluated by 1H and 13C-NMR and AP-MALDI-MS techniques. Differences in the triacylglycerols composition, with particular regard to punicic acid and other CLNA content, were studied in depth. Results showed the prevalence of punicic acid in the triacylglycerol mixture up to the 75%, with clear preponderance in the extract by supercritical fluids. Consequently, other CLNA isomers are, altogether, two-fold less represented in the supercritical extract than in the Soxhlet one. The two oily residues were subjected to solid phase extraction (SPE) and to HPLC-DAD analysis for the polyphenolic isolation and characterization. In addition to HPLC analysis, which showed different content and composition, DPPH analysis to evaluate the antiradical potential showed that the extract obtained with supercritical CO2 was much more active.

Polymorphic Phase Transitions in Bulk Triglyceride Mixtures

Triacylglycerols (TAGs) are among the most important ingredients in food, cosmetic and pharmaceutical products. Many physical properties of such products, incl. morphology, texture and rheology, are determined by the phase behaviour of the included TAGs. Triglycerides are also of special interest for the production of solid lipid nanoparticles, applied for controlled drug delivery and for encapsulation of bioactive ingredients. In this paper, we study the polymorphic behaviour of complex TAG mixtures, composed of 2 to 6 mixed TAGs, by differential scanning calorimetry and X-ray scattering techniques, aiming to reveal the general rules for their phase behaviour upon cooling and heating. The results show that two or more coexisting phases form upon solidification $(\alpha$, $\beta'$ and/or $\beta)$, the number of which depends strongly on the cooling rate and on the number of components in the mixture. No completely miscible $\alpha$- or $\beta'$-phases were observed. The structure of the most stable $\beta$ polymorphs, formed upon subsequent heating of the solidified samples, does not depend on the thermal history of the samples. For all mixtures studied, we observed one-component $\beta$ domains, coexisting with binary mixed $\beta$ domains with composition and structure which do not depend on the specific TAG ratio in the mixture. In other words, for a mixture with $k$ saturated TAGs we observed $(2k-1)$ different $\beta$ phases. These conclusions provide some predictive power when analysing the phase transition properties of TAG mixtures.

Crystallization and Transformation Behavior of Triacylglycerol Binary Mixtures Forming Molecular Compounds of POP/OPO, POP/rac-PPO, and POP/sn-PPO

Fat-based soft materials generally contain different triacylglycerol (TAG) species; hence, TAG mixtures’ phase behaviors determine their important physical properties. TAG binary mixtures typically exhibit eutectic, monotectic, solid solution, and molecular compound (MC) forming phases; among them, the molecular interactions and the crystallization kinetics controlling the formation processes of MC-phases remain unexplored. We used thermal analysis, X-ray diffraction, and optical microscopy to examine the crystallization and transformation kinetics of the three MC-forming 1:1 binary TAG mixtures of 1,3-dipalmitoyl-2-oleoyl glycerol (POP)/1,3-dioleoyl-2-palmitoyl glycerol (OPO), POP/1,2-dipalmitoyl-2-oleoyl-rac-glycerol (rac-PPO), and POP/1,2- dipalmitoyl-3-oleoyl-sn-glycerol (sn-PPO). In the POP/OPO mixture, the MCPOP/OPO crystals of the most stable β form with double chain length stacking (β-2L) were crystallized by simple cooling treatments. In the POP/rac-PPO mixture, the β-2L form of MCPOP/rac-PPO was crystallized by only cooling at 0.1 °C/min, while metastable β′-2L formed at the cooling rates of 0.5 °C/min and 2.0 °C/min; then β′-2L melted and partially transformed into the β form during the heating processes. The POP/sn-PPO mixture showed different and significantly intricate polymorphic behavior. First, a single component of sn-PPO crystallized in β′ with triple chain length stacking (β′-3L) during cooling. This was followed by the crystallization of POP and MCPOP/sn-PPO of the β′-2L forms at slow cooling rates of 0.1 °C/min and 0.5 °C/min, and the α-2L forms at 2.0 °C/min. During heating, the metastable β′ or α forms melted, and MCPOP/sn-PPO transformed into the β form before melting. Observations of isothermal crystal growth rates by optical microscopy revealed that sn-PPO β-3L crystals grow faster than the other single TAGs or MCs, particularly above ∼18 °C. Differences in the crystallization kinetics between sn-PPO, POP, and MCPOP/sn-PPO may cause the separate crystallization while the POP/sn-PPO mixture cools.

Modeling the solid-liquid equilibrium of binary mixtures of triacylglycerols using UNIFAC and predictive UNIQUAC models

The modeling of solid-liquid equilibrium is often performed assuming a series of theoretical simplifications, such as the compounds’ immiscibility in the solid phase. Unfortunately, this is not true for several systems, including food compounds. For example, triacylglycerol (TAG) molecules are the main components of fats and oils. Because of their characteristic solid transition phenomena such as polymorphism and solid solution formation, the quality of oil- and fat-based products is essentially dependent on TAG mixtures’ phase behavior. This work aimed to evaluate the use of a predictive approach based on UNIFAC and a predictive version of UNIQUAC to describe the solid-liquid equilibrium (SLE) behavior of binary mixtures containing TAG species. We put forth a validation test for the modeling approach, using experimental data of TAG mixtures solid-liquid phase diagrams taken from literature. Compared to the adjustable Margules equation and traditional UNIFAC structural parameters approaches, results showed that the predictive modeling approach is quite helpful in representing the experimental data despite limitations in calculating the nonideal behavior of the systems. It is noticeable that using models for calculating the activity coefficients in both phases was essential to the systems’ best description. The SLE theory-based predictive modeling approach used here can be further evaluated for designing mixtures with desired phase behavior, being an interesting tool for describing phase diagrams of TAG mixtures when no experimental data is available.

Substantiation of parameters for the inertial mixer in a biodiesel production reactor

This paper reports results of the theoretical and experimental studies into the processes of transesterification of oils with methyl alcohol, which determined the material balance and established the molecular weight of the components involved in the process of transesterification as input and output products. The theoretical and experimental studies were carried out to calculate the indicators of the process of transesterification of fat-containing wastes depending on a change in the reaction duration and diameter of the inertial mixer of the reactor to accelerate the process of transesterification of oils with methyl alcohol. The process of transesterification is one of the basic methods for modifying the molecular composition of fat raw materials. With transesterification, the composition of fat fatty acids does not change, their statistical redistribution occurs in a mixture of triacylglycerols, which leads to a change in the physicochemical properties of fat mixtures as a result of changes in molecular composition. Transesterification of high-melting animal and vegetable fats with methyl alcohol improves the conversion of oils for the production of biodiesel from fat-containing waste. The results of the theoretical and experimental studies have helped determine the value of the flow rate of the reaction mixture, as well as the values of the geometric dimensions of the reactor, were determined (the diameter of the mixer, d=100÷500 mm; the length of the reactor is 1.5÷2.0 m). Processing of the reaction mixture made it possible to obtain a high degree of homogeneity in the concentration of components with large diameters of the inertial mixer ‒ 300...500 mm at average rotational speeds. The oil conversion has been improved, as well as productivity, by using equipment to produce biodiesel from fat-containing waste. Optimal pump performance is also ensured with minimal power consumption and reactor operation

Optimizing the production of biodiesel from palm olein (Elaeis guineensis Jacq.) using a strong basic anionic resin as a heterogeneous catalyst

In this study, the performance of the Purolite A503S anion exchange resin as a heterogeneous catalyst in the transesterification reaction of palm olein (Elaeis guineensis Jacq.) for ethyl biodiesel production was investigated, and the independent variables were optimized based on the maximum conversion to fatty acid ethyl esters. The response surface methodology (RSM) coupled to a factorial design (2³) with a central composite rotatable design (CCRD) was used for optimization. The effects of temperature, catalyst percentage, palm olein:ethanol molar ratio, and their interactions were evaluated. A reaction time of 10 h was established relating conversion versus time, and the stirring speed was determined by assessing the conversion potential ranging from 250 to 1000 rpm. The reactions were performed in a jacketed reactor coupled to a thermostatic bath. The mixtures of triacylglycerols (TAG), diacylglycerols (DAG), monoacylglycerols (MAG), fatty acid ethyl esters (FAEE), and ethanol were quantified by high-pressure size exclusion chromatography (HPSEC), and glycerol content was determined by stoichiometry. A second-order model was adjusted to explain the experimental data from the 18 factorial design trials. A conversion of approximately 98.10 % in ethyl esters was obtained from the optimised variables using a 17.6 % catalyst, palm olein:ethanol molar ratio of 1:12.85 at 49.4 °C. Despite the long reaction time, the Purolite A503S resin is a potential heterogeneous catalyst in transesterification reactions.

Mixing Phase Behavior of Tripalmitin and Oleic-Rich Molecular Compound-Forming Triacylglycerols

The binary phase behavior of triacylglycerol (TAG) mixtures constituted by PPP (tripalmitin) and either POP (1,3-dipalmitoyl-2-oleoyl-glycerol), OPO (1,3-dioleoyl-2-palmitoyl-glycerol), or MCPOP/OP...

Systematic Investigation of Co-Crystallization Properties in Binary and Ternary Mixtures of Triacylglycerols Containing Palmitic and Oleic Acids in Relation with Palm Oil Dry Fractionation.

This work investigates the molecular interactions within the main triacylglycerols constitutive of palm oil, all having a key role in the multi-step dry fractionation process. Identification of these interactions is possible thanks to the establishment of binary and ternary phase diagrams, using differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD) at variable temperature. The following systems were selected: PPP-POP, PPP-OPP, PPP-POO, POP-OPP, POP-POO, OPP-POO, PPP-POP-POO and PPP-OPP-POO (P: palmitic acid and O: oleic acid), and analyzed in direct mode (heating at 5 °C/min., after melting and quenching at −60 °C), and after tempering for three months at 20 °C (tempered mode). DSC makes it possible to bring out crystallization and melting phenomena associated to polymorphic transitions, which are further characterized (crystalline forms) by XRD. The results show that unsaturated are poorly soluble in fully saturated triacylglycerols, that the intersolubility decreases in proportion to the number of unsaturated fatty acids, that positional isomerism (POP/OPP) has a major impact, that OPP may induce formation of molecular compounds and that co-crystallization properties are highly modified by tempering depending on the polymorphic properties of the systems. This provides a better understanding and allows for effective control of the palm oil dry fractionation process.

An Insight into the Solid-State Miscibility of Triacylglycerol Crystals.

The crystallization properties of triacylglycerols (TAGs) strongly determine the functional properties of natural lipids. The polymorphic and mixing phase behavior of TAG molecules have long been, and still are, a hot topic of research with special relevance for the cosmetic, pharmaceutical, and food industry. To avoid the difficulties arising from the study of whole real fats, studies at the molecular level on mixtures of a limited number of TAGs has become an indispensable tool to identify the underlying causes of the physical properties in lipid systems. In particular, phase diagrams of binary mixtures of TAGs exhibiting a different degree of heterogeneity (monoacid or mixed fatty acids; molecular symmetry; the presence of cis or trans double bonds) have resulted in a significant breakthrough in our knowledge about structure–interaction–function relationships. The present work aims to provide an overview of the main reports regarding binary and ternary TAG systems, from the early studies to the most recent developments.

Tripalmitin‐Driven Crystallization of Palm Oil: The Role of Shear and Dispersed Particles

AbstractWhile palm oil (PO) is a reliable ingredient in formulations for biscuits, cream fillings, and compound chocolates, our understanding of its crystallization behavior and physico‐chemistry pales in comparison to many other fats and oils. Phase diagrams of triacylglycerol (TAG) mixtures may be used to elucidate fat crystal polymorphism and composition of such oils, yet conditions important to the food industry such as shear speed, relevant processing temperatures, and presence of secondary ingredients are regularly overlooked. Here, the effects of shear speed (n = 0–500 RPM), dispersion concentration (0–5 wt.%), and dispersed particle surface chemistry [silica or octadecyl‐functionalized (C18) silica] on the thermal properties of commercial PO when cooled from 60 to 20 °C at 1 °C min−1 were explored, with focus placed on PO's higher‐melting fraction. Using a series of high‐purity TAG standards, X‐ray diffraction revealed PO's higher‐melting fraction as mainly composed of tripalmitin (PPP) crystals and molecular compounds (MC) of PPP either with 1,3‐dipalmitoyl‐2‐oleoyl‐sn‐glycerol (POP) or with POP and 1,2‐dipalmitoyl‐3‐oleoyl‐rac‐glycerol (PPO) in combination, all in a double chain‐length β' (i.e., β'‐2) conformation. Shear increased the formation of lower‐melting α‐2 POP and β'‐2 MCPOP:PPO:PPP crystals while depleting the system of β'‐2 MCPOP:PPP and β'‐2 PPP crystals. This loss was further exacerbated by the addition of dispersed particles to the point where PPP was completely incorporated as MC and β'‐2 PPP crystals were eliminated. While heterogeneous nucleation tends to favor kinetic products of fat crystallization, the interactions between shear and surface chemistry varied between crystal types.

Fatty acid sentinels as covalently bound randomization standards for triacylglycerol (TAG) quantitative analysis.

Quantitative analysis of triacylglycerols (TAG) is impeded by a lack of standards and the huge number of potential TAG molecular species that may be present due to the combinatorial nature of glycerolipids. Randomization of acyl groups yields TAG mixtures with profiles predictable from fatty acid profiles; however, their use as calibration mixtures has been limited. We introduce here the principle of fatty acid isotopic sentinels that are quantitatively added prior to randomization to enable verification that randomization is complete, and that can be used as internal standards. A mixture of two isotopically labeled fatty acid methyl esters (FAME) is prepared at a ratio of 2:1 and the exact ratio is carefully measured by gas chromatography flame ionization detection (GC-FID) and randomized covalently into the acyl groups of TAG mixtures. Reaction with catalytic amounts of NaOCH3 yields complete randomization, such that the product FAME and TAG have the same fatty acid profile. TAG mixture analysis reveals that the isotopic sentinels have been covalently incorporated into the TAG molecular species at <1% deviation from the expected proportions, thus verifying randomization within experimental error. The sentinel principle demonstrated here as covalently incorporated internal standards verifies that randomization chemistry went to completion. It applies in general to use of combinatorial chemistry for quantitative standards.

Hypoglycemic effect of the fruit extracts of two varieties of Rubus rosifolius

Oral glucose tolerance test on male Sprague-Dawley rats was done to determine the hypoglycemic effect of the n-hexane, ethyl acetate and methanol fruit extracts (50mg/kg BW; oral administration) of two varieties of Rubus rosifolius. Metformin was used as a positive control (15mg/kg BW; intravenous administration). The n-hexane extract was most potent and was investigated phytochemically to yield compound 1, a mixture of triacylglycerols. In its oxidized state compound 1 produced a significant hypoglycemic effect which was more effective than metformin for the first 30min of the assay (p=.03) and not significantly different for up to 120min. Mechanisms through which the oxidized triacylglycerol species could form were explored and presented. This is the first account of the hypoglycemic activity of R. rosifolius and it is also the first account of this activity being credited to compounds other than polyphenols and terpenes in Rubus plants. PRACTICAL APPLICATIONS: A significant percentage of the world's population is affected by diabetes and diabetes-related illnesses. One of the most popular antidiabetic drug on the market is metformin which is used to lower blood glucose concentrations. The findings of this study indicate that an oxidized mixture of triacylglycerols is more fast-acting than metformin for the first 30 min of an oral glucose tolerance test. This effect was also not significantly different from that of the popular drug up to 120 min. These results demonstrate the hypoglycemic activity of an oxidized R. rosifolius fruit extract and indicate its potential use in applications such as functional food product development and drug discovery. Therapeutic applications can also include the plant extract as a potential primary treatment or as adjunct therapy to conventional medications.

Characterization of pharmaceutic structured triacylglycerols by high-performance liquid chromatography/tandem high-resolution mass spectrometry and its application to structured fat emulsion injection.

Structured triacylglycerols (STAGs) are a complex mixture of triacylglycerols which are esterified by long-chain fatty acids and medium-chain fatty acids with the same glycerol molecular backbone. As a kind of lipid pharmaceutic excipients, STAGs are used in the pharmaceutical industry as major components of structured fat emulsion injections and play an important role in pharmaceutic energy material because they improve nutritional status with faster elimination in a safe way. The composition and proportion of triacylglycerols in STAGs are closely related to the stability of pharmaceutical preparations and curative effects in the clinic. Therefore, it is necessary to characterize pharmaceutic STAGs using a rapid and accurate method. An analytical method for rapid and accurate determination of triacylglycerols in pharmaceutic STAGs was developed using high-performance liquid chromatography/tandem high-resolution mass spectrometry (HPLC/HRMS). Triacylglycerol components could be well separated on a Waters Xterra MS C8 (2.1 × 100 mm, 3.5 μm) column. Four-dimensional HPLC/HRMS data (high-resolution m/z, MS2 data, retention time and isotopic intensity distribution) were used to identify triacylglycerols using Lipid Data Analyzer (LDA) software and the LIPID MAPS database. Then, these identified triacylglycerol components were relatively quantified by their corresponding normalized peak areas using representative standard curves of structurally similar standard substances. Forty-seven kinds of triacylglycerol components in pharmaceutic STAGs and structured fat emulsion injection were identified and relatively quantified by this method. It has been shown that their retention times are in good correlation with the number of carbon atoms and carbon-carbon double bonds. The main components in pharmaceutic STAGs and structured fat emulsion injection were triacylglycerols containing both medium-chain fatty acids and long-chain fatty acids, while the other components, including triacylglycerols containing three medium-chain fatty acids and triacylglycerols containing three long-chain fatty acids, were relatively low. This study has provided a rapid and accurate approach for the identification and quality control of pharmaceutic STAGs and structured fat emulsion injection and this approach can be extended to other lipid pharmaceutic excipients and used as an effective and reasonable control to guarantee the quality of pharmaceutical preparations.

Prediction of Fatty Acid Incorporation during Enzymatic Interesterification

AbstractWhen a mixture of triacylglycerols and free fatty acids or fatty acid alkyl esters is treated with a random or sn‐1,3 regioselective lipase enzyme, part of these acids will be incorporated into the triacylglycerols while liberating fatty acids that were originally part of these triacylglycerols. Authors generally report the extent of incorporation and then comment on whether equilibrium had been reached and/or acyl migration has been observed. In doing so, they do not refer to articles that provide equations to be used to conclude whether equilibrium has been reached. It is the purpose of the present article to provide these equations and, by using them on literature data, show to what extent conclusions drawn by authors are correct. Besides, the availability of these equations will make it easier to interpret ongoing research on interesterification and to steer its direction in a more appropriate manner.