Ethylcellulose Oleogels Research Articles

Fabrication of stable oleogel-in-water nanoemulsions with ethyl cellulose nanoparticles

Nanoemulsions (NEs) are liquid-based nanosized colloidal systems offering advantages (superior kinetic stability and rheology) compared to macro- and microemulsions. However, stabilization of these emulsions is difficult, since the small droplet sizes in NEs present large surface area-to-volume ratios. Thus, they need to be stabilized by superb emulsifiers to maintain stability. Herein, we report the construction of novel oleogel-in-water NEs with excellent stability against coalescence and phase separation. To do this, nanoparticles (NPs), based on ethylcellulose (EC), were first prepared, and then NEs were made using EC oleogel as the oil phase, ECNPs solution as the water phase, and tween-80 (TW80) as the surfactant. It was observed that NE stabilized by ECNPs, EC oleogel, and TW80 had a significantly lower particle size (201.86 ± 1.57 nm), polydispersity index (0.13 ± 0.06), with no phase separation over 30 days of storage as well as a higher zeta potential (−79.68 ± 1.36 mV), and complex modulus (21441.80 ± 418.21 kPa), as compared to the control NE (stabilized only by TW80). According to the findings, the developed NE has the potential for food and drug delivery applications.

Development and Characterization of Ethylcellulose Oleogels Based on Pumpkin Seed Oil and Rapeseed Oil.

In contrast to rapeseed oil, pumpkin seed oil has yet to be well investigated in terms of oleogelation, and, to the best of our knowledge, no study related to the use of ethylcellulose (EC) in the structuring of this oil has been identified in the current scientific literature. Therefore, the present study evaluated several oleogels formulated with EC as the oleogelator in different concentrations of 7% (OG7) and 9% (OG9), based on cold-pressed pumpkin seed oil (PO) and refined rapeseed oil (RO), as well as on mixtures of the two oils in different combinations: PO:RO (3:1) (PRO) and PO:RO (1:1) (RPO). Physicochemical properties such as visual appearance, gel formation time (GFT), oil-binding capacity (OBC), oxidative and thermal stability, and textural characteristics were analyzed. Analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) were used in the statistical analysis of the data, with a significance level of p < 0.05. EC proved to be an effective structuring agent of the mentioned edible oils; the type of oils and the concentration of oleogelator significantly influenced the characteristics of the obtained oleogels. The 9% EC oleogels exhibited a more rigid structure, with a higher OBC and a reduced GFT. Pumpkin seed oil led to more stable oleogels, while the mixture of pumpkin seed oil with rapeseed oil caused a significant reduction in their mechanical properties and decreased the OBC. After 14 days of storage, all oleogels demonstrated proper oxidative stability within the bounds set by international regulations for edible fats, regardless of the kind of oil and EC concentration. All of the oleogels showed a higher oxidative stability than the oils utilized in their formulation; however, those prepared with cold-pressed pumpkin seed oil indicated a lower level of lipid oxidation among all oleogels. The P-OG9 and PR-OG9 oleogels, which mainly included PO and contained 9% EC, demonstrated the optimum levels of quality in texture, GFT, OBC, and oxidative stability.

Phase inversion of bigels tuned by the concentration of soy protein isolate in the binary hydrogel matrix

Phase inversion of bigels is typically achieved by controlling the oleogel/hydrogel (OG/HG) ratio in previous studies. In this study, a binary hydrogel consisting of different concentrations of soy protein isolate (SPI) to konjac glucomannan (KGM) was designed to fabricate bigels with ethyl cellulose (EC) oleogel at a fixed mass ratio of oleogel to hydrogel (OG:HG), and the phase inversion was subsequently achieved by increasing the concentration of SPI in the binary hydrogel, resulting in a transition from W/O to O/W bigels and then back to W/O bigels. Specifically, when the binary hydrogel contained 1 wt% SPI and 0.5 wt% KGM, the bigel type was O/W. A KGM network existed between the oil droplets of O/W bigels and within the internal phase of W/O bigels, with SPI being adsorbed at the oil-water interfaces of the bigels. As the concentration of SPI increased, the oil-water interfaces became progressively populated with proteins, leading to an increment in droplet diameter and a reduction in hardness, as well as an elevation of free water content within the bigels. This study proposes a novel operational strategy for controlling the phase inversion of bigels and developing encapsulation delivery systems by adjusting the concentration of SPI in binary hydrogels.

Lipophilized rosmarinic acid: Impact of alkyl type and food matrix on antioxidant activity, and optimized enzymatic production

In this study, the initial focus was on exploring the simultaneous impact of the oil-based food matrix and the polarity of rosmarinic acid derivatives on the antioxidant properties. Rosmarinic acid (RA) showed remarkable DPPH, FRAP, and ABTS radical scavenging activities, followed by methyl rosmarinate (MR) and ethyl rosmarinate (ER). In bulk oil, both conjugated dienes and p-AnV values reached a peak in the following order after 30 days: ER > MR > RA = BHT > control (no antioxidant). In the oil structured using monoacylglycerol, MR was more effective than ER and RA. For ethyl cellulose oleogel, emulsion, and gelled emulsion systems, RA was more effective. Additionally, after confirming the importance of the food matrix on the antioxidant activity of RA derivatives, the lipophilization of RA with ethanol was optimized as a model with Lipozyme 435 in hexane. A conversion yield of as high as 85.59% for ER was achieved, as quantified by HPLC-UV and confirmed by HPLC-DAD-ESI-qTOFMS.

Fat coalescence and texture improvement of ice cream based on medium-chain triglyceride oleogel: Effect of gelator type

Academics and industry have invested in creating novel and functional ice creams to meet the growing demand for frozen foods that promote human health and nutrition. This study aimed to investigate the effect of medium-chain triglyceride (MCT) oleogels that prepared by three different gelators on the development of ice creams, as a complete substitute for hydrogenated palm kernel oil (HPKO). The results showed that both beeswax (BW) and phytosterol-oryzanol (PS-GO) caused the fat crystal to grow into three-dimensional spherulites, while ethylcellulose (EC) inhibited crystal size growth. Among the three types of oleogel-based ice creams, the BW sample exhibited the highest coalescence degree, followed by PS-GO and EC. The difference was due to variations in crystal growth and rigid crystal strength. Both BW and PS-GO oleogels improved the firmness of the ice creams by enhancing the formation of crystal network structures in the emulsions. The EC oleogel did not contribute to the overrun of the ice cream. The well-structured fat with partially coalesced aggregates can stabilize the bubbles and hold the aqueous phase of ice creams, preventing the outflow during meltdown. Oleogels that form crystal networks can be employed as a preferable replacement for HPKO in the production of ice cream with superior texture.

Rheological properties of ethylcellulose oleogels of oil glycerolysis products as functional adipose tissue mimetics

Comparative analysis of the rheological behavior of fat analogues and adipose tissue is useful as a means of better understanding the behavior of these ingredients in reformulation and cooking processes. Fat mimicking oleogels were developed based on various enzymatically glycerolized oils and ethylcellulose (EC) of differing molecular weights at a 5% concentration. The dynamic rheological behavior of the oleogels and adipose tissue of different origins (pork, beef, lamb) was studied via amplitude and frequency sweeps. Glycerolized oils and their oleogels behaved as solid-like materials, as elastic moduli were greater than viscous moduli throughout the linear viscoelastic region. Addition of EC produced a more deformable and cohesive product. Solid fat content was a dominant contributor to viscoelastic properties of GP-EC oleogels. Oil systems containing higher levels of saturated fatty acids such as palm olein and shea olein exhibited a more rigid structure, with stiffness comparable to that of pork and beef adipose tissue. Whereas tigernut, peanut, and rice bran oil oleogels were significantly softer and more deformable. Temperature sweep experiments were conducted to visualize the general softening behavior during cooking. The melting of fat dramatically softened both adipose tissue and oleogels. However, the microstructure of adipose tissue was intricately linked to its protein matrix at elevated temperatures, leading to substantial increase of elasticity from 50 °C to 80 °C. Oleogels exhibited thixotropic behavior by recovering their elasticity and functionality over time once the force is removed. This characteristic minimizes the shear related issues during and after the gel-setting process.

Ethylcellulose oleogels of oil glycerolysis products as functional adipose tissue mimetics

Replicating the functionality of animal fat with its plant/microbial counterparts plays a key role in successful design of plant-based analogues of animal-derived foods. Given the intricate structure of animal adipose tissue, merely substituting animal fats in plant foods with saturated bulk fats and oils often results in compromised mechanical and sensory attributes. Animal adipose tissue is comprised of adipocytes encapsulated by connective tissue. Simply replacing this tissue with coconut oil will not succeed in creating a true meat mimetic. Enzymatically glycerolized oils are derived from the conversion of native triacylglycerols in oils into partial glycerides. They are a promising fat alternative that could diminish the need for tropical and hydrogenated oils in plant-based meat products. Oils can be converted into fats using a mild enzymatic reaction without the use of hydrogenation or addition of saturated hardstocks. In this study, we explored the potential of oleogels made from glycerolysis products to mimic adipose tissue. Utilizing various enzymatically structured oils, we formulated oleogels with ethylcellulose (EC) of differing molecular weights (EC20 and EC45) at a 5% concentration. The thermal, microstructural, and mechanical properties of the oleogels were compared to those of whole pork, beef, and lamb adipose tissue. In general, the thermal and structural characteristics of both EC45 and EC20 oleogels closely matched those of the glycerolysis products they originated from. Mechanical properties largely depended on the solid fat content, with oleogel systems richer in saturated fatty acids exhibiting more ordered and rigid structure, akin to adipose tissue. Additionally, pronounced resemblance was observed in thermal softening behavior of some of oleogel systems and that of animal adipose tissue. Our findings highlight the potential of EC oleogels from glycerolysis products in creating meat substitutes, thus preventing the characteristic oil-loss from plant-based meat alternatives when cooked, which lead to dry and grainy sensory textures.

Characterization and comparison of physical properties and in vitro simulated digestion of multi-component oleogels with different molecular weights prepared by the direct method

Due to the hazards of trans fatty acids and saturated fatty acids to human health, research on novel structured lipid-oleogels as lipid substitutes has attracted increasing attention. However, oleogelators of different molecular weights, oils of different properties, and adding lipophilic bioactive substances (LBAS) and/or surfactants to the system lead to differences in oleogel properties. This study characterized and compared the physical properties and in vitro simulated digestion of different multi-component oleogels of carnauba wax oleogels (CWOs), β-sitosterol/lecithin oleogels (S/LOs), and ethyl cellulose oleogels (ECOs) prepared by the direct method. Oleogel strength decreased in the order ECOs > CWOs > S/LOs and peanut oil oleogels > soybean oil oleogels. Regardless of oleogel type, resveratrol (RE) loading and surfactant addition altered the self-assembly or co-assembly behavior of oleogels, which improved their hardness, oil binding capacity (OBC), thermal stability, solid fat content (SFC), viscoelasticity, and RE loading capacity/encapsulation efficiency. The network structure of the different oleogels and the molecular properties of the oleogelators led to differences in the in vitro digestion of multi-component oleogels. Differences in oleogel processing conditions altered their degree of lipolysis and the bioavailability of RE within it. This research sets the direction toward the development of healthier fat substitutes in the future.

Enhanced freeze-thawing stability of water-in-oil Pickering emulsions stabilized by ethylcellulose nanoparticles and oleogels

This study developed water-in-oil (W/O) Pickering emulsions stabilized by ethylcellulose (EC) nanoparticles and EC oleogels, which presented significantly improved freeze-thawing (F/T) stability. Microstructural observation suggested EC nanoparticles were distributed at the interface and within the water droplets, and the EC oleogel trapped oil in the continuous phase. Freezing and melting temperatures of water in the emulsions with more EC nanoparticles were lowered and the corresponding enthalpy values were reduced. F/T led to lower water binding capacity but higher oil binding capacity of the emulsions, compared to the initial emulsions. Low field-nuclear magnetic resonance confirmed the increased mobility of water but decreased mobility of oil in the emulsions after F/T. Both linear and nonlinear rheological properties proved that emulsions exhibited higher strength and higher viscosity after F/T. The widened area of the elastic and viscous Lissajous plots with more nanoparticles suggested the viscosity and elasticity of emulsions were increased.

Maximising olive oil by‐products

Maximising olive oil by‐products

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.

Evaluation of the effect of partial hydrolysis ethyl cellulose on physicochemical properties of soybean oil oleogel

SummaryThe effects of the solvent composition of ethanol and acetic acid (50/50 and 70/30 v/v), time (30 and 60 min) and temperature (65 and 95°C) of hydrolysis were conducted on the structural and physicochemical properties of ethyl cellulose (EC). Differential scanning calorimetry (DSC) and capillary viscometer results revealed that EC hydrolysis significantly decreased glass transition temperature (Tg) and intrinsic viscosity. FTIR spectra of hydrolysed EC (H‐EC) revealed a breakdown of many glycosidic bonds. The oleogels were prepared by H‐EC at the concentration of 6 wt%. Results showed that hydrolysis conditions significantly affected oleogel formation and strength. An optimal oleogel structure was achieved with H‐EC at 65°C, 50/50 solvent ratio (H‐EC65/50). The rheological analysis of H‐EC65/50 oleogel showed higher strength and a lower melting temperature range than EC oleogel. Microscopic observations confirmed that the H‐EC65/50 forms a new structure with many small cavities, probably the main reason for the firmer gel. The prepared formulation could have potential to prepare reduced fat formulations with the suitable melting point and texture.

Structuring of oils with high PUFA content: Evaluation of the formulation conditions on the oxidative stability and structural properties of ethylcellulose oleogels

This study evaluated the formulation of ethylcellulose oleogels as a fat substitute, based on oils with a high content of polyunsaturated fatty acids. Optimal processing conditions for canola, linseed, and chia oil oleogels were determined. The results showed that the oxidative stability was affected to a greater extent in chia oil oleogel, however, the addition of BHT improved the oxidative stability, mainly the peroxide value. Linseed and chia oil oleogels with a high content of polyunsaturated fatty acids (64.28 and 73.02 g/100 g, respectively) were obtained despite the reduction of these with respect to their oils, and no trans fatty acids were produced. Chia oil oleogels were shown to exhibit similar physical properties to linseed oil oleogels in terms of firmness (463.51 ± 7.42 g and 443.03 ± 7.14 g respectively) and rheological behavior. Such a structure led to a dominant elastic character of the oleogels to mimic the mechanical properties of animal fat.

Spray-dried tenofovir alafenamide-chitosan nanoparticles loaded oleogels as a long-acting injectable depot system of anti-HIV drug

The development of suitable drug delivery systems for prolonged action against HIV receives great attention in recent research. Herein, a long-acting injectable (LAI) of Tenofovir alafenamide-chitosan polymeric nanoparticles loaded oleogels developed with sesame oil and ethyl cellulose for prolonged release of the drug is reported for the first time. The research resulted with unique long-acting parenteral formulation for chronic anti-retroviral therapy, based on our experimental in-vitro and ex-vivo studies. The chitosan nanoparticles with 49 % drug content were produced through the spray-drying technique and characterized for their size (106–540 nm) and the other physico-chemical features through SEM, FT-IR, XRD, TGA, and DSC. The ethyl cellulose and sesame oil oleogels were developed through a heat-cool process by incorporating the drug-loaded chitosan nanoparticles. The oleogels exhibited extended release (56 %) of the drug for 16 days, which could be prolonged further to achieve the maximum drug release. Also, the ex-vivo permeation studies of the nanoparticles loaded oleogels demonstrated about 10-fold decrease in the flux and the permeation of the drug due to prolonged release of the drug across dual barriers of chitosan nanoparticles and ethyl cellulose gel matrix. The result provided proof-of-evidence that the developed Tenofovir alafenamide-chitosan polymeric nanoparticles loaded with ethyl cellulose oleogels could be potentially used as the long-acting injectable system for the treatment of patients infected with HIV/AIDS.

Effect of material composition and 3D printing temperature on hot-melt extrusion of ethyl cellulose based medium chain triglyceride oleogel

3D printing is an emerging technology in developing personalized nutrition and has received great attention in the food sector. The use of complex printing materials remains a challenge when the focus is on printability. This work investigated the effect of addition of surfactant polyethylene glycol monostearate, PEG40S (1%, 3%, 5% w/w) on hot extrusion 3D printability of 11% w/w ethylcellulose (EC) based medium chain triglyceride (MCT) oleogel. EC oleogels were characterized using various analyses including oil binding capacity, microscopic structure analysis, rheological analysis, mechanical strength, and melting point profiles. With surfactant addition, additional crystalline structures developed in the polymer network altered the mechanical properties of EC oleogel. To evaluate the temperature-dependent printability, printing temperature was varied (25, 45, 65, 85, and 95 °C); observations inferred that 5% w/w surfactant with printing at 45 °C favored printability with optimal extrusion. Overall, this study provides insights into hot extrusion 3D printing oleogel systems, indicating promising scope for employing such systems for nutrient/nutraceutical delivery as well as the development of novel foods, particularly those focused on fat replacements.

Development of a Self‐Adhesive Oleogel Formulation Designed for the Slow Release of Semiochemicals

AbstractOleogels have been widely studied as delivery matrices for lipophilic compounds. Despite their potential, oleogels are underexplored for the formulation and release of semiochemicals for insect behavior manipulation strategies. An ethylcellulose‐candelilla wax‐oleogel as a suitable carrier for the slow release of volatile semiochemicals, employing the sesquiterpene β‐caryophyllene as a model substance is presented. A current drawback of ethylcellulose oleogels is the high temperature needed during the oleogel preparation procedure, leading to excessive volatilization of the active compounds. Reducing the gelling temperature from 104.8 to 66.9 °C and, thus, the volatile addition temperature by addition of the softener octyldodecanol results in 95.28% entrapment efficiency. Experimental results demonstrate release modifiability by tailoring the matrix crystalline state due to candelilla wax addition. Furthermore, a method is established for analyzing the self‐adhesive properties of the gel on plant leaves. In addition, the gel's self‐adhesive properties employed on apple leaves are synergistically affected by oil leakage and gel stiffness. Olfactometer experiments showed that the formulation is able to enhance the attractiveness of aphid‐infested plants for parasitic wasps. The present study provides a novel matrix‐type semiochemical formulation based on non‐toxic, biobased and biodegradable materials and will contribute to the establishment of oleogels as delivery systems for semiochemicals.

Rheology and Tribology of Ethylcellulose-Based Oleogels and W/O Emulsions as Fat Substitutes: Role of Glycerol Monostearate.

Rheological and tribological properties of oleogels and water-in-oil (W/O) emulsions are important for application in fat substitutes. This study investigated the roles of glycerol monostearate (GMS) in tailoring the structural, rheological and tribological properties of ethylcellulose (EC)-based oleogels and W/O emulsions as potential fat substitutes. The addition of GMS contributed to more round and compact oil pores in oleogel networks. The oleogel with 5% GMS had higher crystallinity, leading to solid state (lower tanδ value), mechanical reversibility (higher thixotropic recovery), but a brittle (lower critical strain) structure in the samples. GMS gave the oleogels and emulsions higher oil binding capacity, storage modulus and yield stress. Under oral processing conditions, GMS addition contributed to higher textural attributes and viscosity. Friction coefficients in mixed and boundary regions of oleogels and emulsions were reduced with the increase in GMS content from 0~2%, but increased with 5% GMS. Rheological and tribological properties of lard, mayonnaise and cream cheese can be mimicked by EC oleogels with 5% GMS, or emulsions with 2% GMS and 2–5% GMS, respectively. The study showed the potentials of oleogel and W/O emulsions in designing low-fat products by tuning the structures for healthier and better sensory attributes.

Addressing criticalities in the INFOGEST static in vitro digestion protocol for oleogel analysis

The interest on the digestive fate of oleogels, i.e., substitutes for solid fats rich in liquid oil, have pushed researchers to use the widely adopted INFOGEST protocol for static in vitro digestion. However, this protocol was originally designed to simulate the digestibility of conventional foods and to accommodate the large fraction of oil in oleogels, researchers have deliberately modified the INFOGEST protocol, inadvertently leading to results difficult to be compared.In this study, we highlighted possible problems that may arise during oleogel simulated digestion such as under- or overestimation of oleogel lipolysis. The effect of oleogel amount, oleogelator type and concentration, and shear applied during digestion on the rate and extent of oleogel digestion was studied. The release of fatty acids during the application of INFOGEST protocol was monitored using the pH-stat method and compared to those analyzed by HPLC-ELSD. Oleogels’ structural information was obtained using brightfield, polarized, and fluorescence microscopy, and DSC. We determined that lipolysis of ethylcellulose oleogels follow the “interaction with enzymes and bile salts” pattern, whereas that of wax oleogels follow the “disintegration of oleogel and interaction with enzymes and bile salts”. We also observed that the chemical composition of wax, crystal morphology, and crystal distribution do not alter the lipolysis of oil entrapped inside the wax crystals. We finally recommended a few minimal but fundamental modifications to the INFOGEST protocol to achieve more reliable results from the static in vitro digestion of oleogels and possibly other lipid-based systems.

W/O emulsions featuring ethylcellulose structuring in the water phase, interface and oil phase for multiple delivery

This study reported a novel approach to stabilize W/O emulsions with nanoparticles and oleogel from ethylcellulose (EC), and the emulsions were applied for multiple delivery. Microstructural observations revealed that EC nanoparticles were distributed within the water droplets and at the interface, and EC oleogel was in the continuous phase. Storage modulus and viscosity were higher, and thixotropic structural recovery rates were lower, in the emulsions with more EC nanoparticles. Both EC nanoparticles and oleogels worked to stabilized the emulsions upon freeze-thawing, as only minor water or oil was released. Upon heating, some EC nanoparticles transited from the interface to the oil phase, and water droplets were aggregated. The interface was recreated when the samples were re-emulsified. When curcumin and anthocyanin were incorporated, both bioactives had improved light stability. During in vitro study, curcumin was mostly released at the early stage of intestinal digestion, while anthocyanin was released at later stage.

Catastrophic phase inversion of bigels characterized by fluorescence intensity-based 3D modeling and the formability for decorating and 3D printing

In this paper, gelatin hydrogels and glycerol monostearate (GMS)-enhanced ethyl cellulose (EC) oleogels were used as two phases for preparing bigels. The proportion of components in bigels was changed to explore the catastrophic phase inversion of bigels, which was analyzed by textural, rheological, laser confocal imaging, 3D stack modeling of techniques, and the measurement of the hydrophile-lipophile balance (HLB). As the oleogel fraction was less than 40 wt%, the bigel presented as the O/W type, and oil droplets were evenly distributed and stabilized by the gelatin, having the size smaller than 15 μm. When the oleogel fraction was 42 wt%, bigels exhibited the semibicontinuous state due to the critical HLB of 8.23 that water and oil phases both had continuous and dispersed phases concurrently. The 3D model of bigels calculated a sharp increase of droplet sizes to 35 μm in the transition state. The water phase in bigels became the dispersed phase when the oleogel fraction was more than 44 wt%, and GMS was mainly responsible for emulsifying and stabilizing water droplets, and the size of water droplets decreased from 35 μm. Applications of bigels in decorating and 3D printing were discussed combined with physical properties of different types of bigels. O/W bigels containing 40 wt% oleogels could inherit the hardness and formability from gelatin hydrogels and have ideal rheological properties for decorating. W/O bigels with 60 wt% oleogels were more suitable to be used as printing ink for 3D printing, resulting from the strong thixotropy of EC oleogels.