A Comparative Study between Beeswax and Glycerol Monostearate for Food-Grade Oleogels

With the aim to produce solid fats with a high percentage of unsaturated fatty acids, oleogels based on olive and peanut oil with different concentrations of beeswax (BW) and glycerol monostearate (GMS) as oleogelators were studied and compared. The critical oleogelator concentration for both BW and GMS was 3%. Thermal properties of the developed GMS-based oleogels pointed to a polymorphic structure, confirmed by the presence of two exothermic and endothermic peaks. All developed oleogels released less than 4% of oil, highlighting their high oil binding capacity. A morphology evaluation of oleogels showed platelet-like crystals, characterized by a cross-sectional length of 50 μm in BW-based oleogels and irregular clusters of needle-like crystals with a higher diameter in GMS-based oleogels. BW-based oleogels showed a solid fat content ranging from 1.16% to 2.27%, and no solid fat content was found at 37 °C. GMS-based oleogels reached slightly higher values of SFC that ranged from 1.58% to 2.97% at 25 °C and from 1.00% to 1.75% at 37 °C. Olive oil-based oleogels with GMS showed higher firmness compared with BW-based ones. The stronger structure network in olive oil/GMS-based oleogels provided a real physical barrier to oxidants, showing a high oxidation stability.

Lecithin's Roles in Oleogelation

This manuscript analyzes the research considering the exploitation of lecithin in oleogelation. The main objective of the work was to gather, analyze, and extract from the existing research data the information that enables us to identify lecithin-dependent roles. Oleogelation is still under research, while using various oleogelators and structurants provides changes on different physico-chemical levels. Multivariable formulations do not facilitate the elucidation of the specific role of any of them. Lecithin, due to its complex structure, big molecule, and amphiphilic nature, can provide different functionalities in complex matrices like oleogels. Therefore, this review identifies and categorizes the functionality of lecithin in oleogelation into four main roles: 1. oleogelation facilitator; 2. structure-forming impact; 3. texturing agent; and 4. functionality provider. Also, the origin and structure-forming characteristics of lecithin, as well as a short summary of the oleogelation process itself, are presented. Our critical analysis allowed us to identify the roles of lecithin in the oleogelation process and categorized them as follows: oleogelator, emulsifier, structural organization facilitator, structural modifier, crystal characteristics modifier, self-assembly promoter, thermal behavior changer, hydrogen-bonded networks promoter, hydrogel structure modifier, texture and structural modifier, gel-like state promoter, oil capacity enhancer, functionality provider, shelf life extender, and bioavailability and bioaccessibility enhancer. Lecithin came out as an important and multifunctional compound whose applications in oleogelation need to be thoroughly pre-considered. It is crucial to grasp all the possible roles of used compounds to be able to predict the final functionality and characteristics of formed oleogel matrices.

Preparation of Novel Flaxseed Oil/Beeswax Oleogel Systems and Its Application in the Improvement of Sodium Alginate Films

The purpose of this study was to prepare a novel kind of flaxseed oil (FO)/beeswax oleogel system and apply it to improve the properties of sodium alginate films. Three single factors, namely the ratio of beeswax/FO, the addition of oleogel, and the addition of glycerol, were optimized based on the comprehensive score of film characteristics: elongation at break (EAB), tensile strength (TS), hydroxyl radical clearance (HRC), and water vapor permeability (WVP) of the film. When the ratio of beeswax/FO was 7.807%, the addition of oleogel was 4.829%, and the addition of glycerol was 31.088%, the comprehensive score of the film characteristics was maximum. Moreover, the Decapterus maruadsi preserved by the produced films were assessed for drip loss, pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substance (TBARS), and fatty acids composition. In comparison to the control, the produced films incorporated with linseed oil/beeswax oleogel had a longer shelf-life than Decapterus maruadsi. In conclusion, the oleogel system prepared via linseed oil/beeswax had good stability and hydrophobicity, which can significantly improve the characteristics of the film and extend the shelf-life of Decapterus maruadsi.

Innovative Approach to Enhance Bioavailability of Birch Bark Extracts: Novel Method of Oleogel Development Contrasted with Other Dispersed Systems

Birch outer bark extract (BBE), containing pentacyclic triterpenes such as betulin, lupeol, and betulinic acid, is a widely recognized natural product renowned for its diverse pharmacological effects. However, its limited water solubility restricts its bioavailability. Therefore, the main objective is to enhance the bioavailability of BBE for pharmaceutical use. In this study, we aimed to develop a dispersion system utilizing a unique oleogel-producing method through the recrystallization of BBE from an ethanol solution in the oil phase. We generated an oleogel that demonstrates a notable 42-80-fold improvement in betulin and lupeol peroral bioavailability from BBE in Wistar rats, respectively. A physical paste-like BBE hydrogel developed with antisolvent precipitation showed a 16-56-fold increase in the bioavailability of betulin and lupeol from BBE in rat blood plasma, respectively. We also observed that the repeated administration of the BBE oleogel did not exhibit any toxicity at the tested dose (38.5 mg/kg betulin, 5.2 mg/kg lupeol, 1.5 mg/kg betulinic acid daily for 7 days). Betulin and betulinic acid were not detected in rat heart, liver, kidney, or brain tissues after the peroral administration of the oleogel daily for 7 days. Lupeol was found in rat heart, liver, and kidney tissues.

Antimicrobial Oleogel Containing Sustainably Prepared Silver-Based Nanomaterials for Topical Application

Oleogels containing silica-silver-based nanomaterials were prepared to be used as potential antimicrobial treatment for preventing and curing skin infections. Fumed silica was used as a bifunctional excipient able to offer support to silver-based nanoparticle growth and act as a gelling agent for oleogel formulation. First, silica-silver composites were prepared following a sustainable method by contact of fumed silica and silver nitrate in the presence of ethanol and successive UV irradiation. The composites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), ATR FT-IR spectroscopy and UV-Vis spectrophotometry. The presence of 8-20 nm spherical nanoparticles, in addition to the silica aggregates and AgNO3 crystals, was detected. The composites showed good antimicrobial activity against the Gram-negative Pseudomonas aeruginosa and the Gram-positive bacteria Staphylococcus aureus and Staphylococcus epidermidis. Thus, they were formulated in an oleogel, obtained using fumed silica as a gelling agent. For comparison, oleogels containing AgNO3 were prepared according to two different formulative techniques. The silica-silver-based oleogels showed good antimicrobial activity and did not show cytotoxic effects for fibroblasts and keratinocytes.

Preparation of Citral Oleogel and Antimicrobial Properties

The objective of this study was to analyze a natural and safe oleogel with antimicrobial properties that can replace animal fats while lengthening the product's shelf life. The oleogel was created using direct dispersion (MG-SO), and its material characterization exhibited the exceptional performance of the hybrid gelant. Additionally, citral was integrated into the oil gel to prepare the citral oleogel (MG-SO). The antimicrobial nature of the material was examined and the findings revealed that it inhibited the growth of various experimental model bacteria, including Escherichia coli, Staphylococcus aureus, Aspergillus niger, Botrytis cinerea, and Rhizopus stolonifer. In addition, the material had a comparable inhibitory impact on airborne microorganisms. Lastly, MG-SON was utilized in plant-based meat patties and demonstrated an ability to significantly reduce the growth rate of microorganisms.

Evaluation of Oleogels Stabilized by Particles of Birch Outer Bark Extract through a Novel Approach

Structuring liquid oils into oleogels using natural and abundant biomass components as gelling agents is of great significance in fields such as foods, pharmaceuticals, and cosmetics. In this work, a more energy-efficient and technologically simpler approach for directly preparing birch outer bark extract particles containing oleogel was used. This method involves introducing birch outer bark extract particles into the oil phase directly from the extract solution, combining both the evaporation of solution and gel formation. As a result, stable oleogels of various vegetable oils (sunflower, almond, olive, and hemp seed) were obtained with birch outer bark extract particle contents of 4-10%. Infrared spectroscopy and particle size analysis confirmed that when increasing the content of extract particles in the oil, increasing self-assembly of extract particles via hydrogen bonding occurs, leading to the formation of a more structured network. This is consistent with gel strength values from rheological tests of oleogels, which also increased with particle concentration. The obtained oleogels showed important properties such as good tolerance to time-dependent deformation, shear thinning, and thermoreversibility.

Bioconjugation of Vegetable Oils with UV Absorbers: New Approach in Skin Photoprotection

We reported the tunable synthesis of new vegetable oil-UV filter bioconjugates using sea buckthorn oil (SBO) and p-methoxycinnamic acid (p-MCA) as an alternative to the common UV filter, ethylhexyl-p-methoxycinnamate (octinoxate). The synthetic strategy is based on the sustainable ring-opening reaction of epoxidized SBO with p-MCA in heterogenous catalysis in eco-friendly solvents. The amount of UV-absorptive moieties grafted on the triglyceride backbone is controlled by different epoxidation degrees as determined by NMR spectroscopy. The performance of the new UV-absorber bioconjugates was assessed by in vitro sun protection factor (SPF) measurements after inclusion in SBO-ethylcellulose (EC) oleogels and comparison with the SPF value of the SBO-EC-octinoxate oleogel with equivalent p-MCA acid moieties (10% wt/wt). The concentration obtained for the SBO-EC oleogel formulated with the bioconjugate with the lowest degree of functionalization, namely 55%, represents 45% of the SPF determined for the SBO-EC-octinoxate oleogel, regardless of the concentration of measured solutions. The new concept of vegetable oil-UV-absorber bioconjugates has potential UV-B photoprotective properties when included in oleogel formulations and deserves further investigation of their properties and stability including association with UV-A absorbers, respectively.

Tiger Nut Oil-Based Oil Gel: Preparation, Characterization, and Storage Stability

In this study, Tiger nut (Cyperus esculentus L.) oil-based oleogels were prepared using the emulsion template method with whey protein (WPI; 0.5-2.5% (w/v) and Xanthan gum (XG; 0.1-0.5% (w/v). The microstructure of the oleogels obtained from the high internal phase emulsion (HIPE) and an emulsion after further shearing were observed using an optical microscope and laser confocal microscopy. A series of rheological tests were conducted to evaluate the effect of WPI and XG concentrations on the strength of the emulsion and oleogel. The texture, oil holding capacity, and oxidative stability of oleogels were characterized. The results showed that XG alone could not form oleogel, while the concentration of WPI had more effect than XG. When WPI was at a fixed concentration, the viscoelasticity of HIPE increased with the addition of XG. This was due to the complexation of WPI and XG, forming a stable gel network between the tight emulsion droplets and thus giving it a higher viscoelasticity. With an increase in WPI concentration, the stability and viscoelasticity of the emulsion were increased, and the oil-holding capacity and gel strength of the oleogels were enhanced. Moreover, the addition of XG could significantly enhance the stability and viscoelasticity of the emulsion (p < 0.05), and an increase in the concentration had a positive effect on it. The oleogels showed high gel strength (G' > 15,000 Pa) and good thixotropic recovery when the XG concentration was higher than 0.3% (w/v). WPI (2.0%) and XG (>0.3%) could be used to obtain HIPE with good physicochemical and viscoelastic properties, which in turn lead to oleogels with minimal oil loss, viscoelastic and thixotropic recovery, and temperature stability. Compared with tiger nut oil-based oleogel, tiger nut oil contained more polyunsaturated fatty acids, which were more easily decomposed through oxidation during storage and had lower oxidation stability. This study provides a reference for the preparation of oleogels from food-approved polymers and provides additional theoretical support for their potential application as solid fat substitutes.

Effect of Soy Wax/Rice Bran Oil Oleogel Replacement on the Properties of Whole Wheat Cookie Dough and Cookies

This study investigated the replacement of butter with soy wax (SW)/rice bran oil (RBO) oleogel in varied proportions in cookie dough and the resulting cookies. The study mainly evaluates the physical, textural, and chemical properties of the butter cookie dough and cookies by replacing butter with SW/RBO oleogel. The dough was assessed using moisture analysis, microscopy, FTIR Spectroscopy (Fourier Transform Infrared) and impedance spectroscopies, and texture analysis. Micrographs of the dough showed that D-50 (50% butter + 50% oleogel) had an optimal distribution of water and protein. D-0 (control sample containing 100% butter) showed the lowest impedance values. Moisture content ranged between 23% and 25%. FTIR spectroscopy suggested that D-50 exhibited a consistent distribution of water and protein, which CLSM and brightfield microscopy supported. Texture analysis revealed that the dough samples exhibited predominantly fluidic behavior. As the amount of oleogel was raised, the dough became firmer. The prepared cookies showed a brown periphery and light-colored center. Further, a corresponding increase in surface cracks was observed as the oleogel content was increased. Cookies moisture analysis revealed a range between 11 and 15%. Minute changes were observed in the texture and dimensions of the cookies. In summary, it can be concluded that replacing butter with oleogel by up to 50% seems to be feasible without significantly compromising the physicochemical properties of cookie dough and cookies.

Waxy Oleogels for Partial Substitution of Solid Fat in Margarines

One of the research directions of oleogels is to study the possibility of their practical application in the food industry as an alternative to solid fats. In this work, the possibility of replacing solid fat in margarine (fat content 82.5%) with oleogels was evaluated. The oleogel content varied from 10 to 50% of the fat phase. The concentration of gelator for which beeswax or wax components (9:1 combination of beeswax and hydrocarbons) were used represented 3% in oleogels. The fatty acid composition of the fat components used, their textural characteristics, and their color were studied. The following physicochemical and rheological properties of margarines were determined: color values, textural and thermal characteristics, and sensory properties. The data obtained were processed using principal component analysis (PCA). Oleogels were characterized by lower textural properties compared to commercial fat (CF), but a lower content of saturated fatty acids. When using oleogels, the color characteristics of the margarines changed insignificantly. A decrease in textural and organoleptic properties was shown when using more than 30% oleogel in the composition of margarines. It was found that an increase in the proportion of oleogel leads to a decrease in the melting enthalpy of margarines. The margarines, depending on the ratio of oleogel in the fat phase, were characterized by a content of saturated fatty acids reduced by 7-35% and increased by a 18-92% level of polyunsaturated fatty acids. Thus, the application of oleogels in margarine technology makes it possible to adjust the fatty acid composition while improving the physicochemical properties.

Optimization of Hazelnut Spread Based on Total or Partial Substitution of Palm Oil

Palm oil is widely used in the manufacturing of hazelnut-based spreads due to its unique fatty acid and triacylglycerol profile and, thus, its crystallization behaviour, which makes it suitable for use in fat-based spreadable products. An interesting solution that enables the replacement of palm oil is given by oleogels made with high nutritional quality oil. In this study, the influence of the replacement of palm oil with different glycerol monostearate/olive oil-based oleogels, as well as the influence of the different amounts of GMS employed in oleogel preparation, on the oil binding capacity, spreadability, and rheological and sensory parameters of hazelnut cocoa spreads was investigated. A design of experiment (DoE) approach, with the adoption of the D-optimal design, was used to plan the cocoa hazelnut spread formulations, with the aim being to identify the optimal formulation with desirable quality parameters in terms of Casson's viscosity, spreadability, and oil binding capacity. The resulting optimized formulation was identified in a spread characterized by a total replacement of palm oil with an oleogel made of 95% olive oil and 5% GMS.

Development and Characterization of Coconut Oil Oleogel with Lycopene and Stearic Acid

Lycopene is a natural bioactive compound possessing higher antioxidant and anti-inflammatory properties, which are known to efficiently eliminate the risk of cancer, cardiac complications, and oxidative stress. Food manufacturers are keen on producing lycopene-fortified food products owing to their numerous health benefits and higher nutritional value. The incorporation of lycopene is limited to food products due to its hydrophobic nature and low chemical stability. This study aims to understand the incorporation of lycopene in Oleogel as a new delivery system. Briefly, lycopene and stearic acid (gelator) were combined at ratios of 0, 25, 50, 75, and 100% (w/w) and added to coconut oil (20 g (w/w) ) for the preparation of edible oleogel combinations. These combinations were characterized for oil binding capacity, swelling capacity, color analysis, and texture profile analysis. Further, the formulations were characterized by FTIR (Fourier Transform Infrared Spectroscopy) and DSC (Differential scanning calorimetry). It was observed that samples prepared with a combination of 50% lycopene and stearic acid were found to possess a firm texture and good stability. Conversely, samples with no gelator produced oleogels with less stability. Further, the FTIR spectra helped determine the network formation in the oleogels, which was stabilized by the hydrogen bond. Furthermore, the results of DSC exhibited that the oleogel combinations with gelator and lycopene were not in the crystalline state, and the oleogels held superior internal structure till 45°C. Overall, oleogelbased carrier systems can be used as an alternative method to encapsulate various bioactive compounds having possible potential applications in the bakery and confectionery industries.

Fabrication and Characterization of Novel Food-Grade Bigels Based on Interfacial and Bulk Stabilization

Novel food-grade bigels were fabricated using zein nanoparticles for interfacial stabilization and non-surfactant gelators (beeswax and tapioca) for bulk stabilization. The present study demonstrated the importance of interfacial stability for biphasic gels and sheds light on the roles of the gelation mechanism and the oil/water ratio of a bigel on its microstructure, physical properties, and digestion behaviors. The results indicated that it is not an easy task to realize homogenization and subsequent gelation in beeswax-tapioca biphasic systems, as no amphiphilic components existed. However, applying the binding of zein nanoparticles at the oil-water interface allowed us to produce a homogeneous and stable bigel (oil fraction reach 40%), which exhibited enhanced structural and functional properties. Oleogel structures play a crucial role in determining the deformation response of bigel systems. As the oil content increased, the mechanical strength and elastic properties of bigels were enhanced. In the meantime, clear bigel-type transitions were observed. In addition, the fabricated bigels were shown to be beneficial for delayed digestion, and the lowest degree of lipolysis could be found in bigel with 50% oleogel.

The Effects of Emulsifier Addition on the Functionalization of a High-Oleic Palm Oil-Based Oleogel

Alternatives to oils with high saturated fatty acid content are often liquid oils (high in unsaturated fatty acids) that have a modified structure created either through additives or processing. Emulsifiers are additives that can be used as structuring agents of liquid fats; this process results in products such as oleogels, which can broaden the applications of these oils. This study assessed and compared the effects of mono- and diglycerides at 3%, 5%, 7% and 10% w/w on the mechanical and thermal properties of high-oleic palm oil (HOPO) oleogels. HOPO was heated to 75 °C and mixed with mono- or diglycerides at those four concentrations. The thermomechanical properties of the melted oleogels were assessed using differential scanning calorimetry (DSC). The melted oleogels were cooled to final temperatures of 5 °C, 10 °C and 15 °C under identical cooling rates, after which a puncture test (via a texture analyzer) was used to assess their textures. Finally, polarized light microscopy was used to assess the mechanical changes induced through emulsifier addition. The results showed that the use of mono- and diglycerides significantly modified the thermal and mechanical properties of the oleogels. The addition of saturated monoglycerides promoted a higher-temperature nucleation stage that did not previously occur in HOPO. The onset crystallization temperature increased with the addition of diglycerides, promoting crystallization at higher temperatures of the high-melting fraction of HOPO. The hardness of the oleogel generally increased with emulsifier addition and a reduction of the temperature. The effect of the temperature on the hardness was significantly greater in the diglyceride oleogel than in the monoglyceride oleogel. This study shows that the addition of mono- and diglycerides allows companies to customize their formulations to achieve desired results that may not previously have been possible, thereby facilitating novel uses for these oils within the industry.

Development of Transdermal Oleogel Containing Olmesartan Medoxomil: Statistical Optimization and Pharmacological Evaluation

Olmesartan medoxomil (OLM) is a first-line antihypertensive drug with low oral bioavailability (28.6%). This study aimed to develop oleogel formulations to decrease OLM side effects and boost its therapeutic efficacy and bioavailability. OLM oleogel formulations were composed of Tween 20, Aerosil 200, and lavender oil. A central composite response surface design chose the optimized formulation, containing Oil/Surfactant (SAA) ratio of 1:1 and Aerosil % of 10.55%, after showing the lowest firmness and compressibility, and the highest viscosity, adhesiveness, and bioadhesive properties (Fmax and Wad). The optimized oleogel increased OLM release by 4.21 and 4.97 folds than the drug suspension and gel, respectively. The optimized oleogel formulation increased OLM permeation by 5.62 and 7.23 folds than the drug suspension and gel, respectively. The pharmacodynamic study revealed the superiority of the optimized formulation in maintaining normal blood pressure and heart rate for 24 h. The biochemical analysis revealed that the optimized oleogel achieved the best serum electrolyte balance profile, preventing OLM-induced tachycardia. The pharmacokinetic study showed that the optimized oleogel increased OLM's bioavailability by more than 4.5- and 2.5-folds compared to the standard gel and the oral market tablet, respectively. These results confirmed the success of oleogel formulations in the transdermal delivery of OLM.

Optimization of Olive Oil Oleogel-Based Emulsion Composition: Effect of Oleogel Composition on Emulsion Characteristics

In this study, the effects of oil, water, glycerol monostearate, carrageenan and alginate concentrations, which have a significant effect on quality parameters in olive oil oleogel-based emulsion (OOE), were investigated and their optimum amounts were determined by mixture design for oleogel production with desired properties. OOE was produced using olive oil, water, glycerol monostearate (GMS), carrageenan and alginate at various concentrations in the range of 0-70%, 30-60%, 0-2%, 0-2% and 0-2%, respectively. The optimum quality parameters of OOE were evaluated in terms of optimum firmness value (5.5-7 N), minimum oil loss and peroxide value. The optimum composition was determined 53.5% olive oil, 43.5% water, 1.1% carrageenan, 0.92% alginate and 0.98% glycerol monostearate (w/w). Produced OOE under determined optimum conditions had 5.81 N firmness, 1.82 meq/O₂ peroxide value and 21.02% oil loss value. The margin of error between the experimentally obtained data and the estimated data in the study is average 2%. The results showed that the formulation used in OOE production have significant effects on the created OOE structure and quality parameters. In addition, different formulations to be created with the results of the present study will contribute to increasing the applicability of OOE in different foods.

Emulsion filled gel with oleogels as oil fraction to enhance nutritional properties of baked products (muffins)

In baked products, such as muffins, the fat reduction to decrease the caloric content is important without detrimental effects on product quality. Among the fat replacers, emulsion-filled gels imply lower fat depending on the oil fraction. The objective of this work was to replace soybean oil in muffins formulation with two different emulsion-filled gels, containing candelilla wax oleogel or ethylcellulose oleogel as oil fraction, to enhance nutritional quality. Colour, texture, crumb quality, moisture, fat, and protein were analysed. Emulsion-filled gels samples resulted in a darker colour, and a more hard and resilient texture, as a reflection of lower cells number developed in crumbs during baking; but there was a lower fat and an increase in protein content. Emulsion-filled gels with candelilla wax as oil fraction are a alternative to decrease caloric content without compromising the energetic values of the foods.

Development and Characterization of Novel In-Situ-Forming Oleogels

PLGA-based in situ forming implants (ISFI) often require a high amount of potentially toxic solvents such as N methyl-Pyrrolidone (NMP). The aim of the present study was to develop lipid in-situ-forming oleogels (ISFOs) as alternative delivery systems. 12-Hydroxystearic acid (12-HSA) was selected as the oleogelling agent and three different oleoformulations were investigated: (a) 12-HSA, peanut oil (PO), NMP; (b) 12-HSA, medium-chain triglycerides (MCT), ethanol; (c) 12-HSA, isopropyl myristate (IPM), ethanol. The effects of the 12-HSA concentration, preparation method, and composition on the mechanical stability were examined using a texture analysis and oscillating rheology. The texture analysis was used to obtain information on the compression strength. The amplitude sweeps were analyzed to provide information on the gel strength and the risk of brittle fractures. The frequency sweeps allowed insights into the long-term stability and risk of syneresis. The syringeability of the ISFOs was tested, along with their acute and long-term cytotoxicity in vitro. The developed ISFOs have the following advantages: (1) the avoidance of highly acidic degradation products; (2) low amounts of organic solvents required; (3) low toxicity; (4) low injection forces, even with small needle sizes. Therefore, ISFOs are promising alternatives to the existing polymer/NMP-based ISFIs.

Crystallization Behavior and Physical Properties of Monoglycerides-Based Oleogels as Function of Oleogelator Concentration

Oleogels have been shown as a promising replacer of hydrogenated vegetable oil. Fatty acid glycerides, including some typical mono- and di-glycerides, were used to form oleogels. The concentration effects of fatty acid glycerides on the crystallization behavior and physical properties of oleogels were investigated by using different analysis techniques. The results showed that all the oleogels formed by saturated fatty acid glycerides (glyceryl monostearate (GMS), glyceryl monolaurate (GML), glycerol monocaprylate (GMC)) exhibited a solid-like behavior and were thermally reversible systems, while a higher amount of unsaturated fatty acid glycerides (monoolein (GMO), diolein (GDO)) were needed to form oleogels. The onset gelation concentration of GMS and GMC was found to be 2 wt% (w/w), while that of GML was 4 wt% by the inverted tube method. The crystallization results illustrated that the GMS and GMC formed small needle-like crystals with the presence of β and β' crystals, while GML formed large flake-like crystals with α crystals in oleogels, and faster cooling rates caused smaller crystals. GMS- and GMC-based oleogels had higher crystallinity, resulting in higher thermal stability and better mechanical properties than GML-based ones at the same monoglyceride (MAG) level. With the increasing MAG content, the oleogels showed a more compact three-dimensional network leading to higher mechanical properties and better thermal stability and resistance to deformations. Hence, MAG-based oleogels, especially GMC ones with medium chain fatty acid, could be a promising replacer for hydrogenation vegetable oils.

The Influence of Emulsifiers on the Physiochemical Behavior of Soy Wax/Rice Bran Oil-Based Oleogels and Their Application in Nutraceutical Delivery

This research evaluated the influence of stearic acid, sunflower lecithin, and sorbitan monooleate on soy wax (SYW)/rice bran oil (RBO)-based oleogels. The physiochemical behavior of oleogel samples was evaluated using colorimetry, microscopy, FTIR, mechanical, crystallization kinetics, X-ray diffraction, and a drug release investigation. The prepared oleogels were light yellow, and adding emulsifiers did not change their appearance. All oleogels showed an oil binding capacity of >98%, independent of emulsifier treatment. The surface topography revealed that emulsifiers smoothed the surface of the oleogels. Bright-field and polarized micrographs showed the presence of wax grains and needles. FTIR spectra indicated that oleogel samples had the same functional group diversity as the raw materials. The oleogel samples lacked a hydrogen-bonding peak. Hence, we postulated that non-covalent interactions were involved in the oleogel preparation. According to stress relaxation studies, the firmness and elastic component of oleogels were unaffected by emulsifiers. However, EML3 (oleogel containing sorbitan monooleate) showed lower relaxing characteristics than the others. EML3 exhibited the slowest crystallization profile. Due to its low d-spacing, EML3 was found to have densely packed crystal molecules and the largest crystallite size. The in vitro drug release studies showed that emulsifier-containing oleogels dramatically affected curcumin release. These results may help customize oleogels properties to adjust bioactive component release in the food and pharmaceutical industries.

The Frying Stability of Oleogel Made from Rice Bran Wax and Sunflower Oil During Intermittent Frying of Potato Chips

There is a need for an alternative method of producing a vegetable oil with high levels of unsaturated fatty acids and physical properties similar to solid fat. The objective of current work was to cut down the amount of oil absorbed by the finished product, increase the frying stability of sunflower oil, and fry potato chips using oleogel without harming their sensory quality. Rice bran wax was applied in this experiment, at rates of 2, 4, and 6 weight percent, and the generated oleogels were then utilized for four days in a succession to fry potato chips for four hours each day. The results suggested that potato chips could be fried using the sunflower oil-rice bran wax oleogel without having an adverse effect on their texture, color, or quality. Furthermore, the produced oleogel was more robust during frying than liquid sunflower oil. During intermittent frying, SFA levels also marginally rose in all samples with the exception of 4% oleogel. The control sample, which was sunflower oil, had the lowest levels of unsaturated fatty acids and poly unsaturated fatty acids at the end of the frying operation. The percentage of oil uptake by the potato chips in the oleogels containing 4 and 2% rice bran wax, on the other hand, was lower than in the control sample. The findings suggested that oleogels could be used as a deep-fat frying medium in household, commercial, and industrial settings.

Utilization of Sunflower Oil-based Oleogel forDeep-Fried Coated Chicken Products

This study aimed to examine the effect of using oleogel as a frying medium on the quality of coated and deep-fried chicken products. Sunflower oil-based oleogels prepared with 0.5%, 1%, 1.5% and 2% carnauba wax were produced for deep frying of coated chicken products and were compared to sunflower and commercial frying oil based on palm oil. The increased carnauba wax concentration in the oleogel decreased the pH, oil, oil absorbance and TBARS value of coated chicken (p < 0.05). Samples deepfried with oleogels containing 1.5% and 2% carnauba wax had the lowest pH values. In addition, since the oil absorption during deep-frying was significantly reduced in these groups (1.5 and 2%), the fat contents of coated products were also lower (p < 0.05). The use of oleogel as a frying medium did not cause a significant change in the color values of the coated chicken products. However, the increased carnauba wax concentration in the oleogel increased the hardness of coated chicken (p < 0.05). As a result, sunflower oilbased oleogels with a carnauba wax content of 1.5% and higher which is healthier in terms of saturated fat content can be used as frying media and can be improved the quality of coated and deep-fried chicken products.

Crystallization and Structural Properties of Oleogel-Based Margarine

Interest in oleogel as a promising alternative to traditional hydrogenated vegetable oil has increasingly grown in recent years due to its low content of saturated fatty acids and zero trans fatty acids. This study aimed to develop wax-based margarine to replace traditional commercial margarine. The wax-based margarine was prepared and compared with commercial margarine in texture, rheology, and microscopic morphology. The possibility of preparing margarine at room temperature (non-quenched) was also explored. The results showed that the hardness of oleogel-based margarine increased as the BW concentration increased. Denser droplets and crystal network structure were observed with the increase in BW content. XRD patterns of oleogel-based margarine with different content BW were quite similar and structurally to the β' form. However, the melting temperature of oleogel-based margarine was over 40 °C at each concentration, which represented a poor mouth-melting characteristic. In addition, the unique, improved physical properties of oleogel-based margarine were obtained with binary mixtures of China lacquer wax (ZLW) and Beeswax (BW), due to the interaction of the ZLW and BW crystal network. The rapid cooling process improved the spreadability of oleogel-based margarine. The margarine prepared by 5% BW50:ZLW50 had similar properties to commercial margarine in texture and melting characteristics (37 °C), which had the potential to replace commercial margarine.

Characterization of the Quality and Oxidative Stability of Hemp-Oil-Based Oleogels as an Animal Fat Substitute for Meat Patties

The effect of the incorporation of rice bran wax (5%; 7%) or candelilla wax (3%; 7%) for production of hemp-oil-based oleogels was analyzed in this study. The experiment was carried out to replace between 0 and 100% of animal fat in meat patties with oleogels. Free fatty acids (FFAs), acid value (AV), oxidative stability index (OSI), conjugated diene value, malondialdehyde value, physicochemical properties, and the sensory properties of oleogels and meat patties were studied. The results indicated that hemp oil had more polyunsaturated fatty acids and lower oxidative stability when compared to oleogels. The OSI for oil was 3.1 h, while for oleogels it was 3.4-3.6 (candelilla case) or 3.7-3.9 (rice bran). Oleogels were able to match pork fat texture properties such as spreadability and adhesiveness in meat patties. However, sensory data for cooked meat patties with animal fat fully replaced by oleogels revealed that samples with 100% pork fat had higher juiciness and taste intensity. Our results showed that a wax-based oleogel had a higher oxidative stability and nutritional profile, but further investigations to mimic pork fat properties in meat patties are necessary.

Hydrogels, Oleogels and Bigels as Edible Coatings of Sardine Fillets and Delivery Systems of Rosemary Extract

Edible coatings provide an alternative way to reduce packaging requirements and extend the shelf life of foods by delaying oxidation and microbial spoilage. Hydrogels, oleogels and bigels were applied as coatings on fresh sardine fillets. The effectiveness of these coatings as delivery systems of rosemary extract (RE) was also evaluated. Three groups of sardine fillet treatments were prepared: (i) the control (C), which comprised sardine fillets without coating, (ii) sardine fillets with plain hydrogel (H), oleogel (O) or bigel (BG) coatings, and (iii) sardine fillets with RE incorporated into the H, O and BG coatings. The different treatments were evaluated for lipid oxidation (TBA test), total volatile basic nitrogen (TVB-N) and microbiological growth during cold storage at 4 °C. Results showed that hydrogel, oleogel and bigel coatings delayed oxidation. The incorporation of RE into coatings significantly retarded lipid oxidation but did not affect the proliferation of microorganisms during storage. When RE was incorporated in the oleogel phase of the bigel coating, it produced significantly lower TVB-N values compared to the control and BG treatments. The incorporation of RE into the oleogel phase of the bigel coating may be a promising method of maintaining the storage quality of the sardine fillets stored at refrigerated temperatures.

Thermally Degradable Inductors with Water-Resistant Metal Leaf/Oleogel Wires and Gelatin/Chitosan Hydrogel Films

Ingestible electronics monitor biometric information from outside the body. Making them with harmless or digestible materials will contribute to further reducing the burden on the patient's oral intake. Here, considering that the inductive part plays an important role in communications, we demonstrate a degradable inductor fabricated with harmless substances. Such a transient component must meet conflicting requirements for both operation and disassembly. Therefore, we integrated a substrate made of gelatin, a thermally degradable material, and a precision coil pattern made of edible gold or silver leaf. However, gelatin itself lost its initial shape easily due to quick sol-gel changes in physiological conditions. Thus, we managed the gelatin's thermal responsiveness by using a tangle of gelatin/chitosan gel networks and genipin, an organic cross-linking agent, and gained insights into the criteria for developing transient devices with thermo-degradability. In addition, to compensate for the lack of water resistance and low conductivity of thin metal foils, we propose a laminated structure with oleogel (beeswax/olive oil). LCR resonance circuits, by connecting a commercial capacitor to the coil, worked wirelessly in the megahertz band and gradually degraded in a warm-water environment. The presented organic electronics will contribute to the future development of transient wireless communications for implantable and ingestible medical devices or environmental sensors with natural and harmless ingredients.

Determination of characteristic evaluation indexes for novel cookies prepared with wax oleogels

BACKGROUND

Wax-based oleogels showed better performance as a substitute for shortening in cookies, but the relationship between the structure and physical properties of wax oleogels and cookies quality has not been elucidated, which limit its further application. In this regard, the effect of structure and physical properties of wax oleogels on the quality of cookies was investigated, and the characteristic indexes for evaluating the quality of novel cookies prepared with wax oleogels were determined.

RESULTS

The results showed that oleogels with 5-9% proportion of rice bran wax (RBX) and candelilla wax (CDW) produced soft cookies with porous structure, desired spread and color. Compared with shortening, wax oleogels with lower solid fat content (SFC, 4.5-11%, 25 °C) and higher β' crystals (2795.7-11 671.3) produced cookies with similar hardness to that of shortening. Besides, the hardness of wax oleogel-based cookies depends more on the amount of crystals than crystal size. In the results, SFC, β' crystals, viscosity and elastic modulus (G') were determined to be the characteristic evaluation indexes for the quality of cookies prepared with wax oleogels. Cookies with wax oleogels with higher SFC, β' crystal, viscosity and G' are softer.

CONCLUSION

The quality of novel cookies prepared with wax oleogels can be controlled by the SFC and β' crystal of wax oleogels. © 2022 Society of Chemical Industry.

Effects of Sorbitan Monostearate and Stearyl Alcohol on the Physicochemical Parameters of Sunflower-Wax-Based Oleogels

A rising health concern with saturated fatty acids allowed researchers to look into the science of replacing these fats with unsaturated fatty acids. Oleogelation is a technique to structure edible oil using gelators. The present study looked for the effect of solid emulsifiers; namely, sorbitan monostearate (SP) and stearyl alcohol (SA), on the physicochemical parameters of oleogels. All the oleogels were formulated using 5% sunflower wax (SW) in sunflower oil (SO). The formulated oleogels displayed irregular-shaped wax crystals on their surface. The bright-field and polarized microscopy showed the fiber/needle network of wax crystals. Formulations consisting of 10 mg (0.05% w/w) of both the emulsifiers (SA10 and SP10) in 20 g of oleogels displayed the appearance of a dense wax crystal network. The SP and SA underwent co-crystallization with wax molecules, which enhanced crystal growth and increased the density and size of the wax crystals. The XRD and FTIR studies suggested the presence of a similar β’ polymorph to that of the triacylglycerols’ arrangement. The incorporation of SA and SP in wax crystal packing might have resulted in a lower crystallization rate in SA10 and SP10. Evaluation of the thermal properties of oleogels through DSC showed better gel recurrence of high melting enthalpy. These formulations also displayed a sustained release of curcumin. Despite the variations in several properties (e.g., microstructures, crystallite size, thermal properties, and nutrient release), the emulsifiers did not affect the mechanical properties of the oleogel. The meager amounts of both the emulsifiers were able to modulate the nutrient release from the oleogels without affecting their mechanical properties in comparison to the control sample.

Impact of Vegetable Oil Type on the Rheological and Tribological Behavior of Montmorillonite-Based Oleogels

We formulated and characterized oleogels based on montmorillonite clay and vegetable oils that could serve as eco-friendly semi-solid lubricants. In particular, we studied the influence of the physical-chemical properties of olive, castor, soybean, linseed, and sunflower oils on the rheological, chemical, thermal, and tribological properties of the semi-solid lubricants. We prepared the oleogels via the highly intensive mixing of vegetable oils with clay at a concentration of 30 wt.%. The oleogels exhibited shear-thinning, thixotropy, structural recovery, and gel-like behavior commonly related to that of a three-dimensional network. The results were corroborated via XRD measurements showing the presence of intercalated nanoclay structures well-dispersed in the vegetable oil. Empirical correlations between the content of saturated (SFAs), unsaturated (UFAs), mono-unsaturated (MUFAs) and poly-unsaturated (PUFAs) fatty acids and the plateau modulus of the aerogels were found. From these experimental results, we can conclude that the fatty acid profile of the vegetable oils exerts an important influence on the rheological and tribological properties of resulting clay and vegetable oil oleogels.

Effect of Palm Oil-Carnauba Wax Oleogel That Processed with Ultrasonication on the Physicochemical Properties of Salted Duck Egg White Fortified Instant Noodles

The present study permutes edible palm oil (PO) into oleogel by incorporating carnauba wax (CW) at two different concentrations (5 g/100 g and 10 g/100 g, w/w) and processing using ultrasonication. The prepared oleogels (OG1: PO-CW (5 g/100 g); OG2: PO-CW (10 g/100 g); and OGU1: PO-CW (5 g/100 g) with ultrasonication, and OGU2: PO-CW (10 g/100 g) with ultrasonication) were compared with PO (control) to deep fry salted duck egg white (SDEW) fortified instant noodles. The impact of different frying mediums on the physicochemical properties of SDEW noodles was investigated. SDEW instant noodles that were fried using OGU and OG samples had a higher L* and b* but lower a* values than those that were fried in PO (p < 0.05). Among the oleogel-fried samples, noodles that were fried in OGU2 and OG2 effectively lowered the oil uptake and showed better cooking properties than OGU1- and OG1-fried noodles, respectively (p < 0.05). Textural attributes such as higher hardness, firmness, chewiness, tensile strength and elasticity, and lower stickiness were noticed in the samples that were fried in OGU, followed by OG and PO (p < 0.05). Scanning electron microstructure revealed a uniform and smoother surface of noodles fried in OGU and OG, whereas the PO-fried sample showed an uneven and rough surface with more bulges. Noodles were tested for fatty acid compositions, and the results found that oleogel-fried noodles retained more unsaturated fatty acids than the control (p < 0.05). During storage of the frying medium after frying the noodles, OGU and OG had higher oxidative stability with lower TBARS, PV, p-AnV, and Totox values than PO at room temperature for 12 days. Overall, using oleogel as frying media improved the physicochemical and nutritional properties of SDEW noodles. This finding could be beneficial for food industries to produce healthy fried food products for consumers.

Food-Grade Bigels with Potential to Replace Saturated and Trans Fats in Cookies

Fats play multiple roles in determining the desirable characteristics of foods. However, there are health concerns about saturated and trans fats. Bigels have been proposed as a novel fat replacer in foods. This research evaluated the role of the type of hydrogel in the development of bigels to be used as fat replacers in cookies. Bigels were made with beeswax/canola oil oleogel and sodium alginate and carboxymethylcellulose hydrogels. The results showed that the peroxide value and binding capacity of bigels were affected by the type of hydrogel used. However, their fatty acid profile, p-anisidine value, oxidative stability, and texture remained unchanged. Using bigels as fat replacers, cookies were obtained with a hardness similar to those with original shortening, showing the potential of bigels for use in foods.

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.

Sunflower Oil-Polyglycerol Stearate Oleogels: Alternative Deep-fat Frying Media for Onion Rings

Sunflower oil oleogels consisting of 3% and 8% polyglycerol stearate (PGSO) were studied as an alternative frying media for onion rings. The physicochemical properties and thermo-rheological characteristics of oleogels were provided. The sensorial quality and texture profiles of onion rings fried in oleogels were compared with those fried in control sunflower oil. Free fatty acids at the end of 6 h were determined, and the trend was reported in decreasing order as PGSO-8, control (sunflower) oil, and PGSO-3.The oxidation induction time for PGSO-8 was significantly lower (1.46 min) than that of the control and PGSO-3 samples following frying. Compared to the control group, the onion ring samples fried in oleogels absorbed approximately 33-37% less oil. It was thought that this reduction would help consumers gain less amounts of calories from the fried products. There were no negative effects of oleogel usage on the L* value, aroma, crispness/texture, and overall acceptability scores for the onion ring samples fried in the oleogels.

l-Lysine-Based Gelators for the Formation of Oleogels in Four Vegetable Oils

Supramolecular oleogel is a soft material with a three-dimensional structure, formed by the self-assembly of low-molecular-weight gelators in oils; it shows broad application prospects in the food industry, environmental protection, medicine, and other fields. Among all the gelators reported, amino-acid-based compounds have been widely used to form organogels and hydrogels because of their biocompatibility, biodegradation, and non-toxicity. In this study, four N^α, N^ε-diacyl-l-lysine gelators (i.e., N^α, N^ε-dioctanoyl-l-lysine; N^α, N^ε-didecanoyl-l-lysine; N^α, N^ε-dilauroyl-l-lysine; and N^α, N^ε-dimyristoyl-l-lysine) were synthesized and applied to prepare oleogels in four kinds of vegetable oils. Gelation ability is affected not only by the structure of the gelators but also by the composition of the oils. The minimum gel concentration (MGC) increased with the increase in the acyl carbon-chain length of the gelators. The strongest gelation ability was displayed in olive oil for the same gelator. Rheological properties showed that the mechanical strength and thermal stability of the oleogels varied with the carbon-chain length of the gelators and the type of vegetable oil. The microstructure of oleogels is closely related to the carbon-chain length of gelators, regardless of oil type. The highest oil-binding capacity (OBC) was obtained in soybean oil for all four gelators, and N^α, N^ε-dimyristoyl-l-lysine showed the best performance for entrapping oils.

Red Pepper and Turmeric-Flavored Virgin Olive Oil Oleogels Prepared with Whale Spermaceti Wax

This study aimed to prepare and evaluate ground red pepper and turmeric added virgin olive oil (VOO) oleogels with whale spermaceti wax (WSW) as organogelator. The concentration of WSW was 8 wt%, and each spice was added at 1 overall wt%. Prepared oleogels were analyzed for main physico-chemical, structural, thermal, rheological properties. Further, aromatics volatile compositions, sensory descriptive analysis and consumer tests were completed. Results indicated that the new oleogels were quite spreadable preparates with acceptable quality indices. The oleogels included β type polymorphs, and showed up to 38℃ of peak melting temperatures. Rheological measurements proved true gel structure stable within applicable frequencies and above 38°C surrounding temperatures. The oleogels were thermo-reversible, and their gel state was recoverable after high shear. Around 25 different aromatic volatile compounds were identified in the two oleogels, most shown to be originating from the VOO, and the spices added. The panel defined and scored the samples with 12 sensory descriptive (hardness, spreadability, liquefaction, sandiness, olive fruit, grassy, waxy, rancid, bitter, hay, cooling and mouth coating) terms. Sensory scores were mostly similar to each other and also within the ranges given in the literature for similar spreadable fat products. Consumer test identified the samples with liked scores (above 4 in 5-max point scale) for appearance, aroma, flavour and overall acceptability. In conclusion, ground spices enriched VOO oleogels with WSW were developed successively to offer consumers spreadable olive oil products to extent consumption patterns with special flavors and health benefits of the spices.

Structuring of Edible Liquid Oil into Smart Thermo-Triggered Soft Matters for Controlled Bioactive Delivery

Growing interest is being dedicated to smart soft matters because of their potential in controlling bioactives upon exposure to an appropriate stimulus. Herein, structuring of edible liquid oil into oleogels and emulgels as smart thermo-triggered soft vehicles for controllable release of diverse nutrients was developed. Edible liquid oil was trapped inside the crystal network structure of phytosterols and monoglycerides resulting in bicomponent solidlike oleogels. Subsequently, both water-in-oleogel (W/O) emulgels and glycerol-in-oleogel (G/O) emulgels were further fabricated by spatial distribution of the stabilizing interfacial crystals around dispersed droplets as well as the network crystals in the continuous phase. Rheological measurements showed that the gel strength of the oleogel-based emulgels depends on the fraction of the aqueous phase and is greater than that of corresponding oleogels due to a filler effect of dispersed aqueous droplets within the crystal network, offering an additional strategy to tune the structure and rheology. Comparatively, introducing glycerol endowed a higher gel strength for the oleogel-based emulgels than water, particularly at increased filler loads. In addition, these soft matters exhibited interesting thermoresponsive nature, which exhibit the flexibility for programmed release of coencapsulated bioactive components upon exposure to an appropriate thermal triggered switchable. The resulted smart thermo-triggered soft matters have emerging opportunities for application in functional active ingredient delivery by on-demand strategies.

The Influence of Edible Oils' Composition on the Properties of Beeswax-Based Oleogels

This study aimed to find relationships between the properties of beeswax-based oleogels and the type of oil used. The influence of linseed, sunflower, olive, and fish oils was studied. For these oils, the fatty acid composition, the content of total polar components, and the iodine value were characterized. Textural and thermodynamic properties were determined for oleogels, the oil-binding capacity was estimated, and the morphology of crystals was studied. The concentration of beeswax in all oleogels was 6.0% w/w. It was shown that the type of oil has a significant influence on all characteristics of the oleogels. The use of different oils at the same technological treatment leads to the formation of crystals of diverse morphology-from platelets to spherulites. At the same time, it was revealed that some characteristics of oils have a varying contribution to the properties of oleogels. The content of total polar materials in oils is associated with a decrease in strength parameters (yield value and elastic modulus) and the oil-binding capacity of oleogels. In its turn, the iodine value of oils has a close positive correlation with the melting and crystallization temperatures of oleogels. The results obtained in this article indicate that the properties of beeswax-based oleogels can be directed by changing the oil composition.

Development of Antioxidant-Fortified Oleogel and Its Application as a Solid Fat Replacer to Muffin

Oleogelation has recently received a great deal of attention in the food industry as a novel alternative technology that physically converts liquid oil into semi-solid gel. Since the functional characteristics of oleogels are dependent on the gelators or bioactive compounds incorporated, this study was undertaken to evaluate the rheological properties and oxidative stability of candelilla wax oleogels fortified with glycerol monostearate (GMS) and β-carotene, and also to investigate their applications to muffin as a shortening replacer. The interaction between candelilla wax and GMS contributed to strengthening the oleogel structure. The oleogels with β-carotene showed the lowest peroxide values than the other samples. The muffins prepared with oleogels for shortening had greater specific gravity and harder texture, but there was no significant difference in the specific volume between the shortening and oleogel samples with GMS. In addition, muffins with β-carotene oleogels showed the highest oxidative stability. Therefore, this study indicated that the incorporation of β-carotene and GMS in oleogels positively affected the storage stability of muffin.

Conversion of Whey Protein Aerogel Particles into Oleogels: Effect of Oil Type on Structural Features

Protein aerogel particles prepared by supercritical-CO₂-drying (SCD) of ground whey protein (WP) hydrogels (20% w/w, pH 5.7) were converted into oleogels by dispersion in selected edible oils (castor, cod liver, corn, flaxseed, MCT, peanut and sunflower oil). The obtained oleogels were analysed for oil content, microstructure, rheological properties, and ATR-FTIR spectra. Except for castor oil, solid-like, plastic materials with comparable composition (80% oil, 20% WP) and rheological properties (G′~3.5 × 10⁵ Pa, G″~0.20 × 10⁵ Pa, critical stress~800 Pa, tanδ~0.060) were obtained. Optical and confocal microscopy showed that the generated structure was associated with the capillary-driven absorption of oil into the porous aerogel particles interconnected via particle-particle interactions. In this structure, the oil was stably entrapped. Results evidenced the reduced role of edible oil characteristics with the exception of castor oil, whose high polarity probably favoured particle–oil interactions hindering particle networking. This work demonstrates that WP aerogels could be regarded as versatile oleogel templates allowing the structuring of many edible oils into solid-like materials.

Formation and Physical Analysis of Oleogels Composed of Edible Oils and High-Melting Fat Crystals

This paper reports the preparation of oleogels composed of edible oils (olive oil, squalene, and caprylic/capric triglyceride) and high-melting fat crystals (tribehenoyl-glycerol (BBB)) to explore the potential use of BBB/edible oil mixtures as low-cost and stable gelators. These mixtures exhibited gel-like behaviors upon rapid cooling and subsequent heating. The mixtures of BBB in the liquid oils formed oleogels at BBB concentrations > 4.0 wt%. The thermal behaviors, crystal structures, and crystal morphologies of mixtures of BBB produced from 6.0 wt% BBB crystals in 94.0 wt% liquid oils were examined following the treatment of these systems according to different temperature regimes. In addition, rheological analysis was conducted to evaluate the physical properties and storage stabilities of the prepared oleogels. It was found that rapid cooling to the crystallization temperature (T_c) from 70°C and subsequent heating to the final temperature (T_f) were necessary to reveal the gel-like behavior. In addition, the crystals treated with rapid cooling were smaller and more uniform in size than those treated with a simple cooling procedure. The differential scanning calorimetry melting peaks were broad or split, and exhibited the eutectic mixing behavior of multi-component triacylglycerols. The X-ray diffraction spectra showed that the melt-mediated α to β transformation of the mixtures was a prerequisite for revealing the gel-like behavior. Moreover, the tempering procedure was found to influence the physical properties of the oleogels, wherein no visible changes were observed for any of the oleogels after rapid cooling and storage for 6 months at 25°C.

Application of Oleogel and Conventional Fats for Ultrasound-assisted Obtaining of Vegan Creams

The purpose of this study was to determine the impact of the fat system type (milk fat - MF, palm oil - PO or oleogel - OG, i.e. RO-LO - rapeseed oil and linseed oil mixture structured by candelilla wax) on the properties of soy creams, in comparison with dairy cream. The MF exhibited the most increase of acid value (2.5-fold), and the RO-LO - increase of peroxide value (3-fold), after 30 days of storage at 20°C. The PO was the most oxidative stable. The OG presented the slightest oxidative changes, the highest slip melting point (39°C) and centrifugal stability (99.6%). The pH and total acidity values of soy creams were similar to soy drink. All creams exhibited unimodal distribution of dispersed particles. The average particle size and dispersity indexes of these emulsions were in range of 1.74-1.80 µm and 0.93-1.16, respectively. The creams with MF or OG exhibited a greater viscosity than sweet dairy cream - 1.66 10^-5 nm^-2, and a higher degree of shear-thinning. The accelerated creaming phenomenon (flotation of lipids molecules) occurred during centrifugation. The cream with PO had the lowest resistance to centrifugal force (instability index - 0.052). The possibility to obtain a stable vegan soy creams containing oleogel (as replacer of conventional fats) has been demonstrated.

Physicochemical Composition and Sensory Quality of Goat Meat Burgers. Effect of Fat Source

Several strategies for producing healthier meat products have been developed. Reducing fat content, using different fat sources, modifying and improving the fatty acid profile or even replacing saturated fat with oleogels are some of the methods used. Goat meat mainly from animals out of quality brands with low commercial value can be valorized when processed, giving the opportunity to increase its consumption and acceptability. Thus, the aim of this study was to study the effect of the replacement of pork as a source of fat with an olive oleogel in burgers manufactured with goat meat and to compare the goat meat burgers with the most common commercial burgers made with beef. Two replications of the burgers were manufactured at different times, and three samples of each burger type (GOO-goat meat burgers with olive oil; GPF-goat meat burgers with pork fat) were randomly selected from each lot manufactured. Each sample was analyzed in triplicate for each physicochemical analysis. At the time, the manufactured burgers were analyzed simultaneously with the commercial burgers. The burgers with olive oil (GOO) showed higher a* and b* than the burgers with pork fat (GPF) and consequently had lower h° and C*. The ashes, protein and collagen contents of the GOO and GPF burgers were similar to those of the other goat meat products. The effect of the incorporation of oleogel on the physicochemical composition of the burgers in relation to the pork fat was expressed in the fat content, 4 and 2.78% for GOO and GPF, respectively. CH burgers have significantly higher fat content (13.45%) than GOO and GPF burgers. The replacement of pork backfat with a vegetable oleogel modified the fatty acids profile, since the GOO burgers had the highest MUFA and PUFA and the lipidic quality, defined by the IA and IT indices, was 0.38 and 0.99, respectively. Globally, goat burgers were sensorially harder and presented a more difficult chewiness than CH. The replacement of the pork back fat with oleogel significantly decreased hardness and chewiness.

Preparation and Evaluation of Virgin Olive Oil Oleogels Including Thyme and Cumin Spices with Sunflower Wax

This study aimed to prepare and evaluate virgin olive oil (VOO) oleogels enriched with thyme and cumin spices with sunflower wax (SW) organogelator. Common physico-chemical, structural, thermal, and rheological analyses were completed. Furthermore, aromatic volatiles composition, sensory descriptive analysis, and consumer tests were provided. Results indicated that spice addition does not interfere with gel formation, stability, and gelation time. The oleogels’ color values were affected by the color of the VOO and the spices. The free fatty acidity and peroxide values were within the acceptable limits for virgin olive oils. There were β’ crystal polymorphs, and melting peak temperatures were around 62 °C. Rheological analyses proved that the oleogels were fairly stable under moderate frequencies, maintained their gelled state until around 52 °C, and recovered their shear induced structural loss after force cessation. There were 22 aromatic volatiles quantified in the samples, which originated from the VOO and spices used as ingredients. A trained panel defined the samples using 13 sensory descriptors. Consumer tests proved that the new oleogels were liked by consumers. Overall, this study provided information and the possibility of spice-enriched and spreadable VOO oleogels to enhance per capita consumption of olive oils with new consumption habits.

Production of Margarines Rich in Unsaturated Fatty Acids Using Oxidative-stable Vitamin C-Loaded Oleogel

Vitamin C (VC)-loaded oleogel (VCOG) with corn oil and monoglyceride stearate was used to replace lipid phase of margarine completely. The oxidative stability of VCOG was evaluated at 60±1°C in a lightproof oven for 18 days and the result showed that VCOG peroxide (> 6 days) and p-anisidine value (> 4 days) was significantly lower than that of bulk oil and VC-free oleogel (p < 0.05). Then, the margarine containing 79.70% VCOG (VCOGM) was in comparison with four commercial butter in sensory and physical characteristic. Results showed that firmness, solid fat content and trans fatty acid of VCOGM were in the lowest values while unsaturated fatty acid and adhesiveness of VCOGM was in the highest values. Furthermore, VCOGM presented the similar springiness, cohesiveness, gumminess, score appearance, texture, taste and overall impression to some/all commercial butters selected in this research (p > 0.05). These results implied that VC-loaded oleogel was an excellent alternative of lipid phase in margarine which confirmed by 55% "definitely buy" and 25% "try once-then decide".

Electrohydrodynamic Processing of PVP-Doped Kraft Lignin Micro- and Nano-Structures and Application of Electrospun Nanofiber Templates to Produce Oleogels

The present work focuses on the development of lignin micro- and nano-structures obtained by means of electrohydrodynamic techniques aimed to be potentially applicable as thickening or structuring agents in vegetable oils. The micro- and nano-structures used were mainly composed of eucalyptus kraft lignin (EKL), which were doped to some extent with polyvinylpyrrolidone (PVP). EKL/PVP solutions were prepared at different concentrations (10–40 wt.%) and EKL:PVP ratios (95:5–100:0) in N, N-dimethylformamide (DMF) and further physico-chemically and rheologically characterized. Electrosprayed micro-sized particles were obtained from solutions with low EKL/PVP concentrations (10 and 20 wt.%) and/or high EKL:PVP ratios, whereas beaded nanofiber mats were produced by increasing the solution concentration and/or decreasing EKL:PVP ratio, as a consequence of improved extensional viscoelastic properties. EKL/PVP electrospun nanofibers were able to form oleogels by simply dispersing them into castor oil at nanofiber concentrations higher than 15 wt.%. The rheological properties of these oleogels were assessed by means of small-amplitude oscillatory shear (SAOS) and viscous flow tests. The values of SAOS functions and viscosity depended on both the nanofiber concentration and the morphology of nanofiber templates and resemble those exhibited by commercial lubricating greases made from traditional metallic soaps and mineral oils.

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.

Oleogel formulation using lipophilic sea buckthorn extract isolated from pomace with supercritical CO2

Lipophilic sea buckthorn pomace extract isolated by supercritical CO₂ (LSBPE) was structurized with different amounts of carnauba wax or beeswax as oleogelators. Oleogels were also made with added water at an LSBPE:water ratio of 70:30. LSBPE was characterized by a favorable ratio of omega-6 to omega-3 fatty acids (1:3) and reasonable amounts of omega-7 fatty acids (4.45% of total), tocopherols (63.0 mg/100 g) and carotenoids (700.1 mg/100 g). The oleogels were characterized by their structural and rheological properties, and physical and chemical stability during storage. Carnauba wax produced a gel-like structure with a highly condensed network of aggregated crystals, while beeswax oleogels displayed elongated crystals which formed interconnected networks. Carnauba wax gels were harder than beeswax gels with better oil-binding capacity and higher crystallization and melting temperatures. Both oleogels showed good physical and oxidative stability during storage due to the immobilization of oil in the three-dimensional structures, and the presence of strong lipophilic antioxidants in LSBPE, respectively. As the proportion of waxes increased from 5 to 17.5%, the hardness, oil-binding capacity, crystallization, and melting temperatures increased in both gels due to the more developed crystalline associations. Addition of water had no significant effect on the physical and chemical stability of oleogels during storage. Water was distributed as small droplets in the crystalline network of oleogelators. However, hardness and oil-binding capacity decreased as water was added. Rich in polyunsaturated fatty acids and bioactive compounds, LSBPE oleogels offer the opportunity to deliver bioactives while simultaneously acting as fat substitutes.

Olive Oil/Pluronic Oleogels for Skin Delivery of Quercetin: In Vitro Characterization and Ex Vivo Skin Permeability

The main objective of this study was to prepare and characterize oleogel as potential carrier for quercetin skin delivery. The formulations were prepared by adding olive oil (5-30%) to Pluronic F127 hydrogel and were evaluated for particle size, zeta potential, viscosity in vitro quercetin release and stability, and were compared with that of Pluronic F127 hydrogel. The selected formulation was characterized for its interaction possibility, ex vivo skin permeation and skin histological changes and safety. The particle sizes ranged from 345.3 ± 5.3 nm to 401.5 ± 2.8 nm, and possessed negative charges. The viscosities of the formulations were found in the range of 6367-4823 cps with inverse proportionality to olive oil percentage while the higher percentages showed higher quercetin release. Percentages of 25% and 30% olive oil showed instability pattern under the conditions of accelerated stability studies. Differential scanning calorimetry verified the existence of quercetin in micellar aggregation and the network in the case of hydrogel and oleogel respectively. Ex vivo skin permeation showed an improved skin permeation of quercetin when 20% olive oil containing oleogel was used. Skin histology after 10 days of application showed stratum corneum disruption and good safety profile. Based on these findings, the proposed oleogel containing 20% olive oil denotes a potential carrier for topical delivery of quercetin.

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.