Structuring of edible oils by alternatives to crystalline fat

Unveiling the formation capacity of multicomponent oleogels: Performance of lecithin interacting with monostearate derivatives

Oleogels have been explored as fat substitutes due to their healthier composition compared to trans and saturated fats, also presenting interesting technological perspectives. The aim of this study was to investigate the compositional perspective of multicomponent oleogels. Structuring ability of lecithin (LEC) (20 or 90 wt% of phosphatidylcholine - PC) combined with glycerol monostearate (GMS), sorbitan monostearate (SMS) or sucrose monostearate (SAC) in sunflower oil was evaluated from oleogels properties. The thermal and rheological properties, microstructure and stability of the oleogels were affected by the difference in the chemical composition of LEC and the ratio between LEC and different surfactants. Interestingly, low-phosphatidylcholine LEC (L20) performed better, although systems formed with reduced amounts of LEC tended to be softer (LEC-GMS) and present high oil holding capacity (LEC-SMS). The mixtures of LEC and monostearate-based surfactants showed different behaviors, depending on the surfactant polar head. In LEC-GMS systems, LEC hindered the self-assembly of GMS in sunflower oil, compromising mechanical properties and increasing oil release. When combined with SMS, LEC acted as a crystal habit modifier of SMS, forming a more homogeneous microstructure and producing stronger oleogels with greater oil binding capacity. However, above the threshold concentration, LEC prevented SMS self-assembly, resulting in a weaker gel. A positive interaction was found in LEC-SAC formulations in specific ratios, since SAC cannot act as a single oleogelator. Results show the impact of solubility balance played by LEC and fatty-acid derivatives surfactant when combined and used as oleogelators. This knowledge can contribute to a rational perspective in the preparation and modulation of the properties of edible oleogels.

Oleofoams: The impact of formulating air-in-oil systems from a lipid oxidation perspective

Air-in-oil foams, or oleofoams, have a great potential for food applications as they can at least partially replace animal or hydrogenated fats, without compromising on textural properties. Yet, there are some challenges to tackle before they can largely be implemented for real-life applications. One of those is the lack of data regarding their oxidative stability. This is an important point to consider, as although using oils rich in polyunsaturated fatty acids (PUFAs) is highly desirable from a nutritional perspective, these fatty acids are particularly prone to oxidation, which leads to major degradations of food quality. This work thus aimed to investigate the oxidative stability of oleofoams prepared with omega-3 PUFA-rich vegetable oils (rapeseed or flaxseed oil) and various types of high melting point lipid-based oleogelators (stearic acid, glyceryl monostearate and stearyl alcohol) when incubated at room temperature. The physical structure and stability of the oleofoams was monitored by various techniques (visual observations, microscopy, DSC, NMR, SAXS and WAXS). Lipid oxidation was assessed by combined measurements of primary (conjugated diene hydroperoxides) and secondary (thiobarbituric acid reactive substances - TBARS) products. We found that the oxidative stability of oleofoams was higher compared to that of the corresponding bulk oil. This protective effect was also found when the oil was simply mixed with the oleogelator without incorporation of air bubbles (i.e., forming an oleogel), and was somewhat modulated depending on the type of oleogelator. These results suggest that oleogelators and the structural changes that they induce limit the cascaded propagation of lipid oxidation in oil-continuous matrices, which is promising in the perspective of future applications.

Exploring Diacylglycerol Oil-Based Oleogels as Effective Stabilizers in Peanut Butter: Performance, Structural Insights, and Sensory Evaluation

In the pursuit of reducing oil separation in peanut butter, oleogels synthesized from diacylglycerol (DAG)-rich peanut oils, using glycerol monostearate (GMS) as the gelator, were examined as alternative stabilizers. In comparison to triacylglycerol (TAG)-rich peanut oils, the DAG oil-based oleogels exhibited better oil-binding capacities across increasing GMS concentrations. Intriguingly, thermal and rheological assessments pointed to a weaker network structure in DAG oil oleogels, as evidenced by their lower crystallization temperatures and reduced viscoelastic parameters (G' and G''). Insight from infrared spectroscopy revealed that this could stem from heightened intermolecular hydrogen bonding between the DAG oil and the gelator. When applied to peanut butter, DAG oil oleogels demonstrated efficacy in minimizing oil separation. Extended storage trials affirmed the long-term stability of peanut butter formulations incorporating these oleogels. Furthermore, sensory evaluations by panelists underscored favorable impressions, suggesting potential consumer acceptance. Overall, this study illuminates the promising role of DAG oleogels as effective, alternative stabilizers in peanut butter formulations.

Novel Organogels from Mauritia flexuosa L.f and Caryodendron orinocense Karst.: A Topical Alternative

Organogels have importance for topical applications because they can be used to deliver drugs in a controlled and prolonged fashion. These are materials consisting of a three-dimensional network of organic molecules dispersed in a solvent. Recent studies have demonstrated that the solvent could be replaced by oils from non-conventional biologic sources. There is a diversity of not-explored species in the Amazon that are promising sources of vegetable oils with a promising composition. This study developed an organogel with buriti (Mauritia flexuosa L.f) and cacay (Caryodendron orinocense Karst.) oils, using cetostearyl alcohol as an organogelator due to its compatibility, stability, security, affordability, and it is readily available. The oils were characterized, and the organogels were synthesized by studying their crystal evolution and oil-binding capacity. The microstructure was evaluated with polarized light microscopy, fractal dimension, FTIR spectroscopy, XRD, and thermal and rheological analyses. It was found that the critical gelation concentration was higher for cacay oil as it possessed a higher amount of polyunsaturated triacylglycerols. The crystals of the buriti organogel had a smaller lamellar shape, a greater surface area, and physical and thermal stability; although, it presented a slower crystal evolution due to the low number of minor compounds and a greater number of saturated triacylglycerols. The polar fraction of the organogelators as well as triacylglycerol and minor polar compounds are important in forming crystallization nuclei. The study showed that Amazonian oils in crystallization processes form microstructures with differentiating physicochemical properties.

Mixed cyclo di-amino acids structured edible oils: a potential hardstock fat mimic

Pure cyclic diamino acids (CdAA) gel differently than combinations of CdAAs, altering the gelation behavior to highly-branched colloidal protein crystal networks reminiscent of traditional fat crystal networks in canola oil, making it an exciting structuring agent for unsaturated oils.

Supramolecular Arrangement and Rheological Properties of Bisamide Gels

We report a systematic study of the gelation behavior of nBA gelators in xylene, with odd and even n-methylene spacers between the amide groups (n = 5-10) and 17 carbons at each end. The melting temperatures (Tm0) of nBA gels are obtained from fitting our DSCN(T) model to the experimental DSC data. The found Tm0 of nBA gels is about 35 °C lower than Tm0 of the pure nBA gelators. This is reasonably well explained by a simple model combining theories of Flory-Huggins and Gibbs free energy of melting (FHM model). We attribute this depression to an increase in entropy upon melting of the gel due to mixing with the solvent. The odd-even alternation in Tm0 of nBA gels, which was also found for the nBA gelators, indicates that the solid structures inside the gels are somewhat similar. This was studied using XRD: similar 00l reflections were found in the XRD patterns of all nBA gels and their nBA gelators. For even nBA gels, the same reflections in the 19-25° (2θ) region confirm that the sheetlike supramolecular structure of the gels is analogous to the lamellar structure of the solid gelators. For odd nBA gels, a slight difference in the reflections around 20-25° (2θ) implies a somewhat different side-by-side packing of odd nBA gels compared to the solid state. This variation is found for all the odd gels, and indeed, they show distinctly different morphologies compared to the even nBA gels. The possible effect of this on the rheological properties is discussed using some inspiration from the Halpin-Tsai model for composites where nBA gels are considered to be analogous to composite materials. The change of the storage modulus (G') with the shape factor of woven fibers and sheets in nBA gels (20 wt %) indicates that a rheological odd-even effect might indeed be present.

Impact of the Morphology of Electrospun Lignin/Ethylcellulose Nanostructures on Their Capacity to Thicken Castor Oil

This study reports on a novel strategy for manufacturing thickened gel-like castor oil formulations by dispersing electrospun lignin/ethylcellulose nanostructures. These thickened formulations were rheologically and tribologically evaluated with the aim of being proposed as alternative ecofriendly lubricating greases. Low-sulfonate kraft lignin (LSL) and ethylcellulose (EC) were dissolved in a DMAc:THF mixture at different concentrations (8, 10, and 15 wt.%) and LSL:EC ratios (50:50, 70:30, and 90:10) and subjected to electrospinning. The resulting electrospun nanostructures were morphologically characterized. EC acting as the cospinning polymer improved both LSL spinnability and the oil structuring ability. Solutions with a high lignin content achieved microsized particles connected by fibrils, whereas solutions with a high EC content (50:50 ratio) and LSL/EC total concentration (10 and 15 wt.%) yielded beaded or bead-free nanofibers, due to enhanced extensional viscoelastic properties and nonNewtonian characteristics. The gel-like properties of electrospun nanostructure dispersions in castor oil were strengthened with the nanostructure concentration and the EC:LSL ratio, as a result of the formation of a more interconnected fiber network. The oleodispersions studied exhibited a satisfactory frictional response in a tribological contact, with friction coefficient values that were comparable to those achieved with traditional lithium-lubricating greases.

Exploring how changes to the steroidal core alter oleogelation capability in sterol: γ-oryzanol blends

Oleogels based on sterols such as β-sitosterol blended with the sterol ester γ-oryzanol are a very interesting class of systems, but there are aspects of their formation and structure that remain elusive. It has previously been shown that a methyl group on the C30 position of the sterol-ester plays an important role in gelation. This work explored the effect that having C30 methyl groups on both the sterol and the sterol-ester had on the gelation process and subsequent gel structure. Lanosterol and saponified γ-oryzanol (which was synthesized as part of this study) were identified as materials of interest, as both feature a methyl group on the C30 position of their steroidal cores. It was observed that both sterols formed gels when blended with γ-oryzanol, and also that lanosterol gelled sunflower oil without the addition of γ-oryzanol. All of these gels were significantly weaker than that formed by β-sitosterol blended with γ-oryzanol. To explore why, molecular docking simulations along with AFM and SAXS were used to examine these gels on a broad range of length scales. The results suggest that saponified γ-oryzanol-γ-oryzanol gels have a very similar structure to that of β-sitosterol-γ-oryzanol gels. Lanosterol-γ-oryzanol gels and pure lanosterol gel, however, form with a totally different structure facilitated by the head-to-tail stacking motif exhibited by lanosterol. These results give further evidence that relatively slight changes to the molecular structure of gelators can result in significant differences in subsequent gel properties.

Possibility of using low-field nuclear magnetic resonance (LF-NMR) and differential scanning calorimetry (DSC) to monitor frying oil degradation

In this work, chemical degradation of oil was determined as a function of frying time during intermittent deep-fat frying (i.e. 185 °C for 5 h per day for 12 days) and was correlated with the thermal characteristics as measured by Differential Scanning Calorimetry (DSC) and proton mobility by Low-Field Nuclear Magnetic Resonance (LF-NMR). Linear increases of FFAs and PV were observed as a function of frying time. FFAs and PV were strongly correlated with the melting enthalpy. The melting enthalpy of oil decreased exponentially, and the melting temperature remained nearly same until 30 h of frying time followed by a sharp increase. The relaxation times of rigid, semi-rigid and mobile protons (i.e. T 2b , T 21 , and T 22 ) decreased with the increase of frying time. The decrease of T 21 , and T 22 were steeper as compared to the T2b. A strong correlation was observed between conventional chemical parameters (i.e. PV and FFAs), and T 21 and T 22. The populations of the three pools of protons as identified by Inverse Laplace Transformation and Gaussian distribution function showed the interchange of the protons with the chemical changes during frying. It is concluded that chemical free DSC and LF-NMR could be potential methods to monitor frying oil degradation.

Fabrication of chitosan-cinnamaldehyde-glycerol monolaurate bigels with dual gelling effects and application as cream analogs

In this study, chitosan-based bigels were fabricated, where glycerol monolaurate was added in MCT oil to produce a gelled lipid phase and cinnamaldehyde was included in the lipid phase in order to act as a crosslinking agent. The synergistic effect of pH on chemical crosslinking effects was investigated. The potential of using these bigels as an alternative to cream was also investigated. The pH of the aqueous phase played an important role in controlling the extent of the Schiff-base reaction promoted by cinnamaldehyde. At pH 3.8, the bigels formed were homogenous but at pH 5.0 and 5.5 they exhibited phase separation, which highlighted the importance of chemical crosslinking. To better mimic the properties of real cream, span 80 was added to create a more homogeneous and smoother structure of the bigels. These bigels might provide a healthy and more sustainable alterative to food products that contain plastic fats, like cream.

Soy oil and SPI based-oleogels structuring with glycerol monolaurate by emulsion-templated approach: Preparation, characterization and potential application

In this study, soybean oil-based oleogels were prepared using soy-protein isolate (SPI) and glycerol monolaurate (GML) in an emulsion-template approach. The rheological, texture, microstructure, and oil-retention properties of the obtained oleogels were analyzed. Results showed that the soy oil-based oleogel prepared with 6 wt% GML exhibited high oil loss, low-hardness, and needle-like morphology compared to the soy-oil/SPI-based oleogel. On the other hand, soy oil-based /SPI-based oleogels structured by 3 or 6 wt% GML presented moderate thermal-stability and lowest oil loss than those prepared without GML. Furthermore, SPI-based oleogel containing 6 wt% GML showed highest free fatty acids release (62.07%) with significantly improved elastic modulus and apparent viscosity. Additionally, the obtained oleogels displayed the occurrence of van der Waals interactions and intermolecular hydrogen bonds, presenting enhanced thermal stability. These results contribute to a better understanding of oleogelation-based emulsions for formulating trans-free and low-saturated foodstuffs with desired physical and functional properties.

Building blocks of β-sitosterol-γ-oryzanol gels revealed by small-angle neutron scattering and real space modelling

Mixtures of β-sitosterol and γ-oryzanol form gels in a range of organic solvents. Despite being widely studied, particularly as potential oleogels for food application, details of the intrinsic gel-forming building blocks remain unclear. Small-angle neutron scattering (SANS) combined with solvent contrast variation has been used to evaluate potential structural models. While evidence exists that the building blocks are hollow cylinders (tubules), the simultaneous fitting of twelve contrast-varied SANS data sets indicates that the previously proposed model of double walled tubules is incorrect. Predicted scattering based on real space models provides compelling evidence that the origin of the gelling behaviour is the limited assembly of adjacent tubules to form a space-filling network of fibrils.

Synergistic effects of oleogelators in tailoring the properties of oleogels: A review

Conventional solid fats play a crucial role as an ingredient in many processed foods. However, these fats contain a high amount of saturated fats and trans fats. Legislations and dietary recommendations related to these two types of fats set forth as a consequence of evidence showing their deleterious health impact have triggered the attempts to find alternate tailor-made lipids for these solid fats. Oleogels is considered as a novel alternative, which has reduced saturated fat and no trans fat content. In addition to mimicking the distinctive characteristics of solid fats, oleogels can be developed to contain a high amount of polyunsaturated fatty acids and used to deliver bioactives. Although there has been a dramatic rise in the interest in developing oleogels for food applications over the past decade, none of them has been commercially used in foods so far due to the deficiency in their crystal network structure, particularly in monocomponent gels. Very recently, there is a surge in the interest in using of combination of gelators due to the synergistic effects that aid in overcoming the drawbacks in monocomponent gels. However, currently, there is no comprehensive insight into synergism among oleogelators reported in recent studies. Therefore, a comprehensive intuition into the findings reported on synergism is crucial to fill this gap. The objective of this review is to give a comprehensive insight into synergism among gelators based on recent literature. This paper also identifies the future research propositions towards developing oleogels capable of exactly mimicking the properties of conventional solid fats to bridge the gap between laboratory research and the food industry.

A Review of Potential Use of Amazonian Oils in the Synthesis of Organogels for Cosmetic Application

New strategies for the delivery of bioactives in the deeper layers of the skin have been studied in recent years, using mainly natural ingredients. Among the strategies are organogels as a promising tool to load bioactives with different physicochemical characteristics, using vegetable oils. Studies have shown satisfactory skin permeation, good physicochemical stability mainly due to its three-dimensional structure, and controlled release using vegetable oils and low-molecular-weight organogelators. Within the universe of natural ingredients, vegetable oils, especially those from the Amazon, have a series of benefits and characteristics that make them unique compared to conventional oils. Several studies have shown that the use of Amazonian oils brings a series of benefits to the skin, among which are an emollient, moisturizing, and nourishing effect. This work shows a compilation of the main Amazonian oils and their nutraceutical and physicochemical characteristics together with the minority polar components, related to health benefits, and their possible effects on the synthesis of organogels for cosmetic purposes.

W/O high internal phase emulsion featuring by interfacial crystallization of diacylglycerol and different internal compositions

High internal phase emulsions (HIPEs) show promising application in food and cosmetic industries. In this work, diacylglycerol (DAG) was applied to fabricate water-in-oil (W/O) HIPEs. DAG-based emulsion can hold 60% water and the emulsion rigidity increased with water content, indicating the water droplets acted as "active fillers". Stable HIPE with 80% water fraction was formed through the combination of 6 wt% DAG with 1 wt% polyglycerol polyricinoleate (PGPR). The addition of 1 w% kappa (κ)-carrageenan and 0.5 M NaCl greatly reduced the droplet size and enhanced emulsion rigidity, and the interfacial tension of the internal phase was reduced. Benefiting from the Pickering crystals-stabilized interface by DAG as revealed by the microscopy and enhanced elastic modulus of emulsions with the gelation agents, the HIPEs demonstrated good retaining ability for anthocyanin and β-carotene. This study provides insights for the development of W/O HIPEs to fabricate low-calories margarines, spread or cosmetic creams.

Physicochemical properties of beef burger after partial incorporation of ethylcellulose oleogel instead of animal fat

The aim of this study was to evaluate the physicochemical properties of beef burger after substitution of animal fat with the ethylcellulose (EC) oleogel. Therefore, sesame oil oleogels were prepared using EC in concentrations of 10%, and cooled at 25 °C. The fatty acid profile of EC oleogel compared with animal fat. Then, the EC oleogel was incorporated to hamburger at the 0, 25 and 50% instead of animal fat and color and textural properties as well as cooking loss, cooking shrinkage, fat absorption, and lipid oxidation of the beef burgers were evaluated. As an outcome, the EC oleogel contained high levels of linoleic and linolenic acids, while the palmitic and stearic acids were lower than the animal fats, and myristic acid was not detectable. Replacement of animal fat with EC oleogel upgraded the quality of final product by reducing cooking loss and fat absorption. Production of beef burger with EC oleogel decreased the oxidation process during frozen storage as well as cooking loss and fat absorption, and enhanced textural properties including chewiness and hardness. Improvement of nutritional and technological properties of hamburgers contained EC oleogel makes it a desirable candidate for animal fat substitution.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at(10.1007/s13197-021-04970-4).

Gelation behavior and crystal network of natural waxes and corresponding binary blends in high-oleic sunflower oil

Wax-based oleogels attract considerable attention for their perfect gelation properties, but the waxy mouthfeel severely limits their implementation in food. Herein, we developed a novel strategy via designing the crystal network to produce wax-based oleogels with a suitable mouthfeel. Four natural waxes with different melting points were selected as oleogelators to investigate the gelation behavior. All waxes at 5 wt% concentrations could form stable oleogels with low-frequency dependence. Especially, rice bran wax (RBW) and beeswax (BW) with high oil-binding capacity indicated that the ordered crystal network with fiber or needle-like morphology is more suitable for trapping liquid oil. Interestingly, China lacquer wax (ZLW) presented satisfactory oral melting characteristics according to the melting properties. Subsequently, to enhance the structure of ZLW-oleogel, RBW and BW with desirable crystal networks were added at varying mass ratios (100:0, 75:25, 50:50, 25:75, and 0:100). The binary oleogels exhibited monotectic behavior from thermodynamic phase diagrams. The polarization microscope indicated that similar needle-like crystals in BW/ZLW system enhanced the order of network structure, while long fiber-like crystals by RBW dominated the crystallization of RBW/ZLW binary oleogels. Finally, the BW/ZLW binary oleogels with ratios of 25:75 and 50:50 showed no-waxy mouthfeels in sensory analysis. These findings provide strong theoretical support for the application of wax-based oleogels in plastic fats replacement. PRACTICAL APPLICATION: Natural wax-based oleogel has been widely investigated due to the high oil binding capacity and perfect gelation properties. But its waxy mouthfeel severely limits the application in the food industry. In this study, oleogels with no-waxy an mouthfeel were obtained by designing wax-blend crystalline network. These findings provide strong theoretical support for the application of wax-based oleogels in plastic fats replacement.

Oleogel-based emulsions: Concepts, structuring agents, and applications in food

This review discusses the application of oleogel technology in emulsified systems. In these systems of mimetic fats, water-in-oil or oil-in-water emulsions can be obtained, but, here, we cover emulsions with an oil continuous phase in detail. Depending on the percentage of water added to the oleogels, systems with different textures and rheological properties can be developed. These properties are affected by the characteristics and concentration of the added components and emulsion preparation methods. In addition, some gelators exhibit interfacial properties, resulting in more stable emulsions than those of conventional emulsions. Oleogel-based emulsion are differentiated by continuous and dispersed phases and the structuring/emulsification components. Crucially, these emulsions could be applied by the food industry for preparing, for example, meat products and margarines, as well as by the cosmetics industry. We present the different processes of emulsion elaboration, the main gelators used, the influence of the water content on the structuring of water-in-oleogel emulsions, and the structuring mechanisms (Pickering, network, and combined Pickering and network stabilization). Finally, we highlight the applications of these systems as alternatives for reducing processed food lipid content and saturated fat levels.

Insight into the Secondary Metabolites of Geum urbanum L. and Geum rivale L. Seeds (Rosaceae)

The present study aimed at the identification and quantitation of phenolic compounds, fatty acids, and further characteristic substances in the seeds of Geum urbanum L. and Geum rivale L. For this purpose, individual components of extracts recovered with MeOH, CH₂Cl₂, and by cold-pressing, respectively, were characterized by HPLC-DAD/ESI-MSⁿ and GC/MS and compared with reference compounds. For both Geum species, phenolic compounds, such as flavonoids and gallic acid derivatives, and triterpenes, such as saponins and their aglycones, were detected. Surprisingly, both Geum species revealed the presence of derivatives of the triterpenoid aglycons asiatic acid and madecassic acid, which were characterized for the first time in the genus Geum. Furthermore, the fatty acids of both species were characterized by GC–MS after derivatization. Both species showed a promising fatty-acid profile in terms of nutritional properties because of high proportions of unsaturated fatty acids. Linoleic acid and linolenic acid were most abundant, among other compounds such as palmitic acid and stearic acid. In summary, the present study demonstrates the seeds of G. urbanum and G. rivale to be a valuable source of unsaturated fatty acids and bioactive phenolics, which might be exploited for nutritional and cosmetic products and for phytotherapeutic purposes.

Oleogels-Their Applicability and Methods of Characterization

Oleogels or, more precisely, non-triglyceride structured lipid phases have been researched excessively in the last decade. Yet, no comprehensive knowledge base has emerged, allowing technology elevation from the laboratory bench into the industrial food application. That is partly due to insufficient characterization of the structuring systems studied. Examining a single composition decided upon by arbitrary methods does not stimulate progress in the research and technology area. A framework that gives much better guidance to product applications can easily be derived. For example, the incremental structure contribution concept is advocated as a parameter to compare the potency of structuring systems. These can straightforwardly be determined by combining solubility data and structural measurements in the recommended manner. The current method to determine the oil-binding capacity suffers from reproducibility and relevance. A newly developed method is suggested to overcome these shortcomings. The recommended new characterization of oleogels should contribute to a more comprehensive knowledge base necessary for product innovations.

Formation, structural characteristics and physicochemical properties of beeswax oleogels prepared with tea polyphenol loaded gelators

In this study, a tea polyphenol (TP) loaded beeswax gelator (TP gelator) was constructed and incorporated into soybean oil to improve the oxidative stability of oleogels. The effects of TP on the structure and storage stability of oleogels were investigated. The TP gelator prepared by embedding TP into beeswax improved the dispersity of TP in lipids. The thermal characteristics and X-ray diffraction analysis showed that the components of the TP gelator coexisted homogeneously and TP was well dispersed in beeswax. The Fourier-transform infrared spectra indicated that the phenolic hydroxyl group of TP had intermolecular force with the quaternary ammonium nitrogen in the choline portion of soybean lecithin. The formation of needle-like crystals by beeswax restricted the flow of liquid oil, and TP did not participate in the construction of the internal network structure of the oleogel. In the accelerated storage experiment at 60 °C, the peroxide value of the TP loaded oleogel decreased by 60.6% at the end of the storage period compared with soybean oil. TP was successfully embedded in the oleogel without changing its structure, which not only solved the problem of poor dispersion of TP in oil, but also showed a significant inhibitory effect on lipid oxidation.

Large amplitude oscillatory shear (LAOS) for nonlinear rheological behavior of heterogeneous emulsion gels made from natural supramolecular gelators

The linear and nonlinear rheological behaviors of heterogeneous emulsions gels made from natural glycyrrhizic acid (GA) nanofibrils and sitosterol-oryzanol mixtures (sterols) were investigated using small amplitude oscillatory shear (SAOS) and large amplitude oscillatory shear (LAOS). The nonlinear rheological response was qualitatively analyzed using normalized Lissajous-Bowditch curves. The microstructure of the emulsion gels strongly depended on the concentration of sterols in the oil phase, and showed a percolated segregated network at 10-20 wt% sterols due to the partial coalescence of droplets, and a jamming transition without coalescence at higher sterols concentration of 30 wt%. The microstructure differences led to different linear and nonlinear viscoelastic behaviors of these emulsion gels. SAOS tests showed that the oil phase structuring by the sterols significantly enhance the viscoelasticity of GA nanofibril emulsion gels, and the percolating emulsion gels exhibited higher elasticity than the jammed emulsion gel, as evidenced by a lower damping factor and frequency power-law exponent. The data of crossover strain, phase angle, and the normalized Lissajous-Bowditch curves from LAOS tests further revealed that compared to the samples in a jammed state or without oil phase structuring, the emulsion gels with a percolating segregated network showed higher structural elasticity and thus were more resistant to large deformations, probably due to the slow relaxation of rigid, hydrodynamically interacting clusters of partially coalesced droplets. These findings could potentially aid in the design of novel emulsion gels, based on all-natural and sustainable building blocks, with specific textural and functional properties for foods, cosmetics, and pharmaceutical applications.

Crystallization, microstructure and polymorphic properties of soybean oil organogels in a hybrid structuring system

Organogels are semi-solid systems where the liquid phase is immobilized for three-dimensional network self-sustained formed by structuring agents capable to hold a larger quantity of liquid oil. The use of these structuring agents or crystallization modifiers, as specific triacylglycerols, emulsifiers and high molecular weight - high melting point lipids, have been recognized as the main alternative for obtaining low saturated fats for food formulation. The aim of this work was to evaluate the crystallization, microstructure and polymorphism properties of hybrid soybean oil (SO) organogels, formulated with 6% (w:w) of structuring agents through a centroid simplex system added singly, in binary or ternary association of candelilla wax (CW), sorbitan monostearate (SMS) and fully hydrogenated palm oil (FHPO). The thermal behavior, crystallization kinetics, physical stability by temperature cyclization, microstructure and polymorphism were evaluated. FHPO and CW increased the stability and ability to form crystalline networks in organogels, while SMS accelerated the crystallization process. The structuring agents increased the initial and final crystallization temperatures, even as the melting temperatures and the enthalpy values of organogels. Time-temperature cyclization (cyclization 1: 5 °C/48 h + 35 °C/24 h + 5 °C/24 h; cyclization 2: 35 °C/48 h + 5 °C/72 h) showed that all the systems resulted in firm and stable organogels, except when SMS or FHPO were used singly. CW promoted formation of denser crystalline networks with higher solids content, quick crystallization onset and higher melting points that indicates adequate thermal resistance; while FHPO increased the solid content although it was effective to obtain organogels only at the cooling temperature (5 °C). The binary interaction of FHPO + CW increased the thermal resistance of organogels; and the interactions among SMS + CW and SMS + CW + FHPO although it was effective to obtain organogels. Regardless of the presence and proportions of structuring agents, organogels were characterized by beta polymorphism.

Functional properties of dairy phospholipid gels

In this study dairy phospholipid (PL) gels were made using 3 different concentrations of PL (15%, 30%, and 45%) and soybean oil to determine the gel-forming ability and functional traits that dairy PL have. After 24 h of storage the visual stability, crystal morphology, solid fat content, melting behavior, viscosity, and oil binding capacity of the gels were evaluated. All samples showed visual stability, whereas polarized light microscopy showed that high concentrations of PL reduced PL mobility, preventing tubular micelles from forming at high concentrations of PL (45%). Solid fat content increased with an increase in PL concentration. The melting enthalpy increased as the concentration of PL increased. The viscosity was assessed at 0.01, 0.1, and 1.0 1/s shear rates. A significant difference was observed between the 45% PL samples and the other samples at low and intermediate shear, but at high shear levels, a significant difference was only seen between the 15% PL sample and the other samples. The oil binding capacity showed a significant difference between the 45% PL sample and the other 2 samples. This study shows that dairy PL can be added to a vegetable oil to produce semi-solid material with appropriate functional properties.