Functional Fat Blends of Specific Mixture Systems of Saturated-Oleic Mixed Acid Triacylglycerols: Impact of Molecular Compound Crystal Formation

Critically increasing high demands for trans-free and reduction of saturated fats have been asking lipid researchers to develop novel ideas of materials designs of hard stocks for various edible fats

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 (trilaurinor 1,2,3-trilauroyl-glycerol) and POP (1,3-dipalmitoyl-2-oleoyl-glycerol), PPO (1,2-dipalmitoyl-3-oleoyl-rac-glycerol), orthe 50POP/50PPO blend able to form a molecular compound. This research aims to provide an insight into the molecularinteractions ruling the physical behavior of fat blends of lauric (i.e., coconut oil) and non-lauric lipids (cocoa butter, palmoil, 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 ofthe 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 POPand PPO showed to favor the solubility of LLL as compared to the binary systems. Accordingly, promoting the presence oftriacylglycerols forming molecular compound in specific fat blends may help reducing eutectic or incompatible interactionsamong triacylglycerol molecules in the solid state. These lead to phase separation and are a major cause of the restrictedapplicability of lauric oils in the confectionery and chocolate industries

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

Deliciosos polimorfos

El polimorfismo, tan habitual y conocido por geólogos en minerales como la calcita-aragonito, el diamante-grafito y el grupo de la sílice, se extiende a muchos otros campos. Desde la cristalografía y la mineralogía, dando un gran salto en los materiales pero no en los fenómenos, el polimorfismo también tiene lugar en productos alimentarios. En particular, los triacilgliceroles, los cuales constituyen los componentes mayoritarios de grasas y aceites, tales como el chocolate, el aceite de oliva o el jamón ibérico, muestran un complejo comportamiento polimórfico (Larsson et al., 2006). La caracterización de sus formas cristalinas resulta crucial en aplicaciones de la industria alimentaria para satisfacer las necesidades del consumidor, optimizar procesos industriales o desarrollar nuevos productos. Sin embargo, el polimorfismo también podría ser utilizado como herramienta discriminatoria entre diferentes categorías de un mismo producto alimentario, así como para la detección de acciones fraudulentas (Bayés-García et al., 2016)

Chocolate: a useful model for teaching basic terms on Crystallography and Thermodynamics

By using a simple, attractive and sweet model, as chocolate is, many scientific concepts related to different disciplines, which are often understood as complex and dull by most students, may be introduced. In particular, the student may be able to develop crystallographic concepts and methodologies combined with some thermodynamic aspects, which have been historically known as complex and arduous disciplines. Hence, the student may enjoyably assimilate complicated concepts such as polymorphism, mixing behavior, crystal morphology, crystal size or thermodynamic stability, and may also be capable of understanding their application to daily life. These concepts may be applicable to any kind of material and can be more deeply developed depending on the level required

Solvent dependent formation of Cu (II) complexes based on isonicotinamide ligand

Five solvent-dependent Cu(II) compounds have been synthesized with [Cu(μ-OAc)(μ-Pip)(MeOH)]2 (OAc = acetate; Pip = 1,3-benzodioxolecarboxylate) and isonicotinamide (Isn) as an auxiliary ligand in different solvents. In all the compounds, Pip units are displaced resulting in dimeric [Cu(μ-OAc)(OAc)(Isn)2(solvent)]2 (solvent = MeOH (2a), dmf and H2O (3) or H2O and HPip (4a)), paddle-wheel [Cu(μ-OAc)2(Isn)]2·2dmso (5) or monomeric compounds [Cu(OAc)2(HOAc)(Isn)2]·HOAc (6). All of them have been characterized by analytical and ATR-FTIR techniques and their X-ray crystal structures solved. The OAc anions construct different arrays and exhibit different coordination modes depending on the solvent used. The supramolecular expansion is constantly determined by the amide-amide pattern and the role of the occluded solvent molecules. This tendency is confirmed by Hirshfeld Surface analysis. Finally, the thermal stability of compound 4a has been analyzed

Polymorphic fingerprint as an approach to authenticate Iberian pig categories

High-commercial-value products are often susceptible to food fraud. Among them, Iberian dry-cured ham is highly appreciated due to its particular and sensory, but also nutritional, properties. There are four different Iberian ham categories (namely bellota, recebo, cebo de campo and cebo), which directly depend on the rearing system of the pig during the last stage of the fattening phase. However, there is still a lack of a normalized and robust method capable of authenticating the different product categories and, therefore, preventing mislabeling. In the present work, we characterized the polymorphic behavior of raw (before curing) lipid extracts belonging to the four categories of Iberian pig. A total of 80 different samples were analyzed by DSC, and synchrotron radiation XRD experiments were carried out for selected ones. The results obtained showed that bellota and recebo categories exhibited essentially the same crystallization and polymorphic behavior and this was significantly different (p < 0.05) from that of cebo de campo and cebo. The latter exhibited higher crystallization and melting temperatures than bellota and recebo samples, due to the occurrence of an additional β′-2L polymorphic form. By considering the differences in rearing systems of pigs belonging to the different categories, we concluded that the key factor which determined the polymorphism of Iberian pig lipid extracts was not the physical exercise practiced by the pig, but the inclusion of acorns in the feeding system. This work demonstrated that thermal and crystallographic techniques, like DSC and XRD, may be promoted to be used as fingerprinting tools for the authentication of high-value food products

In situ crystallization and transformation kinetics of polymorphic forms of saturated-unsaturated-unsaturated triacylglycerols: 1-palmitoyl-2,3-dioleoyl glycerol, 1-stearoyl-2,3-dioleoyl glycerol, and 1-palmitoyl-2-oleoyl-3-linoleoyl glycerol

We examined the influence of dynamic thermal treatment (variation of cooling/heating rates) on the polymorphic crystallization and transformation pathways of 1-palmitoyl-2,3-dioleoyl glycerol (POO), 1-stearoyl-2,3-dioleoyl glycerol (SOO), and 1-palmitoyl-2-oleoyl-3-linoleoyl glycerol (POL), which are major saturated-unsaturated-unsaturated (SUU) triacylglycerols (TAGs) of vegetable oils and animal fats (e.g., palm oil, olive oil, and Iberian ham fat). Using mainly a combination of differential scanning calorimetry (DSC) and synchrotron radiation X-ray diffraction (SR-XRD), we analyzed the polymorphic behavior of TAGs when high (15 °C min− 1), intermediate (2 °C min− 1), and low (0.5 °C min− 1) cooling and heating rates were applied. Multiple polymorphic forms were detected in POO, SOO, and POL (sub-α, α, β'2, and β'1). Transient disordered phases, defined as kinetic liquid crystal (KLC) phases, were determined in POO and SOO for the first time. The results demonstrated that more stable forms were directly obtained from the melt by decreasing the cooling rates, whereas less stable forms predominated at high cooling rates, as confirmed in our previous work. Regarding heating rate variation, we confirmed that the nature of the polymorphic transformations observed (solid-state, transformation through KLC phase, or melt-mediation) depended largely on the heating rate. These results were discussed considering the activation energies involved in each process and compared with previous studies on TAGs with different saturated-unsaturated structures (1,3-dioleoyl-2-palmitoylglycerol, 1,3-dipalmitoyl-2-oleoyl-glycerol, trioleoyl glycerol, and 1,2-dioleoyl-3-linoleoyl glycerol)

Lipid crystallization kinetics - roles of external factors influencing functionality of end products

The extent of crystallization and transformation of lipids, and their network formation, play decisive roles in determining physical properties (e.g., hardness, texture, rheology, and spreadability) of lipid-based food products. In these products, the lipid materials are present in rather complicated physical states such as mixtures of solid and liquid lipids or emulsified with water phases. In addition, various external influences are applied during actual production in a factory. Therefore, exploration of lipid crystallization under multiple external influences is necessary to improve the functionality of lipid-based food products

From trioleoyl glycerol to extra virgin olive oil through multicomponent triacylglycerol mixtures: crystallization and polymorphic transformation examined with differential scanning calorimetry and X-ray diffraction techniques

The polymorphic crystallization and transformation behavior of extra virgin olive oil (EVOO) was examined by using differential scanning calorimetry (DSC) and X-ray diffraction with both laboratory-scale (XRD) and synchrotron radiation source (SR-XRD). The complex behavior observed was studied by previously analyzing mixtures composed by its main 2 to 6 triacylglycerol (TAG) components. Thus, component TAGs were successively added to simulate EVOO composition, until reaching a 6 TAGs mixture, composed by trioleoyl glycerol (OOO), 1-palmitoyl-2,3-dioleoyl glycerol (POO), 1,2-dioleoyl-3-linoleoyl glycerol (OOL), 1-palmitoyl-2-oleoyl-3-linoleoyl glycerol (POL), 1,2-dipalmitoyl-3-oleoyl glycerol (PPO) and 1-stearoyl-2,3-dioleoyl glycerol (SOO). Molten samples were cooled from 25 °C to − 80 °C at a controlled rate of 2 °C/min and subsequently heated at the same rate. The polymorphic behavior observed in multicomponent TAG mixtures was interpreted by considering three main groups of TAGs with different molecular structures: triunsaturated OOO and OOL, saturated-unsaturated-unsaturated POO, POL and SOO, and saturated-saturated-unsaturated PPO. As confirmed by our previous work, TAGs belonging to the same structural group displayed a highly similar polymorphic behavior. EVOO exhibited two different β'-2 L polymorphic forms (β'2-2 L and β'1-2 L), which transformed into β'-3 L when heated. Equivalent polymorphic pathways were detected when the same experimental conditions were applied to the 6 TAG components mixture. Hence, minor components may not exert a strong influence in this case