Different organogel formulations used as beef fat (BF) replacement (0%, 20%, 40%, 60%, and 80%) were utilized to optimize the mechanical properties of frankfurters. Organogels, made of canola oil ...(CO), included different concentrations of ethyl cellulose (EC) and sorbitan monostearate (SMS). They consisted of: 8% EC + 1.5% SMS referred to as organogel‐I (OG‐I), 8% EC + 3.0% SMS (OG‐II), and 10% EC + 1.5% SMS (OG‐III), which were found promising in a previous study when used at 100% replacement. Replacement of BF with organogels at all levels could bring down the very high hardness values (texture profile analysis and sensory) of frankfurters prepared using CO by itself, relative to the BF control. OG‐I and OG‐II quantity had no significant effect on hardness and springiness, being similar in many cases to the BF and lower than the CO control. Shear force values of all organogel treatments were not significantly different from one another, and were between the BF and CO controls. Smokehouse yield showed a pattern of decreasing losses with increasing organogel replacement level. Sensory analysis revealed that using CO by itself significantly increased hardness, but structuring the oil (via organogelation), brought it down to the BF control value in all OG‐I and OG‐II formulations. Juiciness was significantly reduced by using liquid oil but increased with raising the amount of organogels. Oiliness sensation increased with higher organogel substitution and was actually higher than the beef control. The study demonstrates the potential use of vegetable oil structuring in replacing the more saturated BF in emulsion‐type meat products.
Practical Application
Organogelation allows for the replacement of beef fat with gelled vegetable oils. This permits the manufacture of saturated fat‐reduced and polyunsaturated fatty acid enhanced meat products. This technology opens up the possibility of creating a whole family of niche meat products with enhanced nutritional properties but with similar sensory characteristics.
•The gelation mechanism of ethylcellulose oleogels does not involve secondary ordered structure formation.•Increasing polymer molecular weight led to an increase in final gel strength, the modulus at ...cross-over, and the gel point temperature.•Cooling/heating rates affect gel modulus only for the low molecular weight samples.•Thermal analysis detected no evidence for thermal transitions during gelation or melting of the gels.
The characterization of the thermo-gelation mechanism and properties of ethyl cellulose/canola oil oleogels was performed using rheology and thermal analysis. Thermal analysis detected no evidence for thermal transitions contributed to secondary conformational changes, suggesting a gelation mechanism that does not involve secondary ordered structure formation. Rheological analysis demonstrated a relationship between the polymer molecular weight and the final gel strength, the cross-over behavior as well as the gel point temperature. Increasing polymer molecular weight led to an increase in final gel strength, the modulus at cross-over, and the gel point temperature. Cooling/heating rates affect gel modulus only for the low molecular weight samples. A decrease in gel strength with increasing cooling rate was detected. The cross-over temperature was not affected by the cooling/heating rates. Cooling rate also affected the gelation setting time where slow cooling rates produced a stable gel faster.
The potential of organogels (oleogels) for oil structuring has been identified and investigated extensively using different gelator-oil systems in recent years. This review provides a comprehensive ...summary of all oil-structuring systems found in the literature, with an emphasis on ethyl-cellulose (EC), the only direct food-grade polymer oleogelator. EC is a semicrystalline material that undergoes a thermoreversible sol-gel transition in the presence of liquid oil. This unique behavior is based on the polymer's ability to associate through physical bonds. These interactions are strongly affected by external fields such as shear and temperature, as well as by solvent chemistry, which in turn strongly affect final gel properties. Recently, EC-based oleogels have been used as a replacement for fats in foods, as heat-resistance agents in chocolate, as oil-binding agents in bakery products, and as the basis for cosmetic pastes. Understanding the characteristics of the EC oleogel is essential for the development of new applications.
•Influence of solvent on the properties of ethylcellulose oleogels was reported.•Oil polarity positively impacted gel strength; higher polarity produced stronger gels.•Hansen solubility parameters ...were used to optimize solvent/polymer interactions.•Polar small molecules greatly increased gel strength via sight-specific interaction.•Established unrefined oils greatly influence gel strength via minor components.
Ethylcellulose (EC) is the only known food-grade polymer able to structure edible oils. The gelation process and gel properties are similar to those of polymer hydrogels, the main difference being the nature of the solvent. The present study examines the influence of solvent quality on the large deformation mechanical behavior of EC oleogels. Two alternative strategies for manipulating the mechanical response of these gels were evaluated; manipulating the bulk solvent polarity and the addition of surface active small molecules. Gel strength was positively correlated to solvent polarity when blending soybean oil with either mineral oil or castor oil. This behavior was attributed to the ability of the polar entities present in the oil phase to interact with the EC gel network. The addition of the small molecules oleic acid and oleyl alcohol resulted in a substantial enhancement in gel strength up to 10wt% addition, followed by a gradual decrease with increasing proportions. Binding interactions between EC and these molecules were successfully modeled using a Langmuir adsorption isotherm below 10wt% addition. Furthermore, the thermal behavior of stearic acid and stearyl alcohol also indicated a direct interaction between these molecules and the EC network. Differences in the mechanical behavior of gels prepared using refined, bleached, and deodorized canola or soybean oils, and those made with cold-pressed flaxseed oil could be attributed to both oil polarity, and the presence of minor components (free fatty acids). Shorter pulsed NMR T2 relaxation times were observed for stronger gels due to the more restricted mobility of the solvent when interacting with the polymer. This work has demonstrated the strong influence of the solvent composition on the mechanical properties of EC oleogels, which will allow for the tailoring of mechanical properties for various applications.
The physical structure and properties of ethylcellulose (EC) powders of different molecular weights were examined. A molecular weight in the range of 20–144 kDa with a large polydispersity was ...determined. EC thermal analysis revealed a glass transition at ~130 °C and a melting temperature at ~180 °C. Glass transition temperatures increased with polymer molecular weight. Wide angle (WAXS) analysis detected an amorphous broad peak at q = 1.5 Å⁻¹ and a distinct Bragg’s peak at 12.6 Å, which seems to be related to a supramolecular ordered structure of the polymer. These observations were confirmed using high temperature powder X-ray diffraction analysis where the crystalline peak disappeared above the melting temperature of the polymer. Ultra-small angle (USAXS) results were fitted to the Bouacage fractal unified model and fractals with an average size of 100–600 nm with a relatively smooth surface were predicted. This prediction was confirmed by transmission electron microscopy (TEM) images. According to our results, the EC polymer has a semi-crystalline structure, with crystalline domains within an amorphous background.
•Ethylcellulose oleogels shear moduli increased 10-fold upon addition of 1% soy lecithin.•LAOS analysis was used to characterize yielding behavior of the gels.•Lecithin modified the LAOS ‘thickening’ ...response of the gels.•Thickening of gels having unsaturated lecithin partly matched that of a model fat.
Addition of 1% (w/w) soy lecithin increased the shear moduli 10-fold and gel hardness 20-fold for 10% ethylcellulose (EC) oleogels. Higher lecithin addition levels or addition to gels with a higher EC concentration caused smaller increases. Similar trends were observed in the penetration force of the gels. Gels displayed thermal reversibility and a high temperature plateau at T≈120–130 °C. Large amplitude oscillatory shear rheology demonstrated similar solid-to-fluid transitions indicating that the polymer drives elastic softening and failure of the network. However, EC oleogels differed in their resistance to flow: the addition of unsaturated lecithin promoted a more gradual thickening response compared to gels containing saturated lecithin or only EC (the last two types of gels display strong intra-cycle thickening and thinning, more indicative of brittle failure). The thickening response of EC oleogels containing unsaturated lecithin, resembles more closely that of a model edible fat (lard).
•Surfactant head group plays an important role on the final gel network properties.•The addition of surfactant to EC oleogel reduces the cross-over temperature and the gel point temperature.•Glycerol ...based surfactants plasticize the EC backbone more efficiently than sorbitan based surfactants.•The addition of surfactant to EC oleogel yields stronger gels due to surfactant–polymer interactions.
The effects of surfactant addition to ethyl-cellulose (EC) based oleogels were examined with respect to the chemical nature of the “head” and “tail” groups of the surfactant. Unique sigmoidal temperature dependent rheological behavior was observed upon surfactant addition, suggesting additional organized structure formation. Glycerol-based surfactant addition lead to greatest decrease in the sol–gel and gel–sol transition temperatures compared to sorbitan-based surfactants. This behavior can be attributed to the plasticizing nature of the small head group of glycerol compared to the larger head group of sorbitan surfactants. A significant increase in the penetration force of the gels was observed upon surfactant addition, suggesting possible surfactant–polymer interactions which stiffen the polymer network. Thermal analysis detected a reduction in both SMS and GMS crystallization peak temperature and enthalpy. In the case of GMS, two melting peaks were observed upon EC addition to the oil phase, suggesting EC/surfactant interactions. These results demonstrate the effects of surfactant head group structure on EC oleogel rheological properties.
We investigated the crystallization and rheological behavior of organogels developed with commercial (MSGC) and pure (MSGP) monoglycerides in safflower oil solutions (0.5% to 8% wt/wt). The MSGC was ...composed of 1-mono-stearoyl-glycerol (1-MSG, 37.7%) and 1-mono-palmitoyl-glycerol (1-MPG, 54.0%), and the MSGP essentially by 1-MSG (93.51%). The elastic (G′) and loss (G″) moduli of the MSGC and MSGP–oil solutions were measured from 80°C until achieving 5°C, and then during isothermal conditions. The d(G′)/d(time) rheograms, where d(G′)/d(time) is the difference in G′ between subsequent time–temperature conditions during cooling, followed closely the phase transition observed by the monoglycerides (MG). The d(G′)/d(time) profile showed that the formation of the inverse lamellar α mesophase provided a limited structure to the vegetable oil. In contrast, the crystallization of the sub-α phase in the MSGC-oil system, and of the sub-α1 and sub-α2 phases in the MSGP-oil system structured the vegetable oil through the uptake and retention of oil within their microstructure. Additionally, smaller crystals formed the three-dimensional crystal structure in the MSGC organogels. This is in comparison with the larger crystal size observed in MSGP organogels. Nevertheless, for a similar MG concentration the MSGC organogels showed higher G′ and solid fat content (SFC) than the MSGP organogels, and the differences were greater as the MG concentration increased. We consider that the mixed sub-α structure developed by 1-MSG and 1-MPG in the MSGC-oil systems favored the incorporation and retention of higher amounts of oil, in comparison with the sub-α1 and sub-α2 structures developed just by 1-MSG in the MSGP-oil systems.
•We studied the organogelation of commercial (MSGC) and pure (MSGP) monoglycerides.•MSGC organogels had higher elasticity (G′) than MSGP organogels.•The d(G′)/d(time) rheograms followed closely the monoglyceride crystallization.•Organogels' oil binding is associated with the sub-α phase structure.
Plant-based cheese is one of the fastest-growing sectors in the food industry. However, since the products lack critical functionalities and nutrition compared to their dairy-based counterparts, ...considerable room remains for improvement. High protein plant-based cheese containing 18%w/w protein and waxy starch was used as the base cheese formulation and demonstrated that while the texture and functionality can match that of processed dairy cheese, the excessive oil loss needed to be addressed. Oil modulation and stabilization techniques were explored here by creating oleogels with 1% w/w ethylcellulose (EC), 2%w/w beeswax (BW) or 2%w/w candelilla wax (CW) in coconut oil. Oleogels were incorporated into the cheese, where all oleogelators successfully reduced the cheese product's oil loss while maintaining the associated melting and stretch properties. The oleogels had a more significant effect on the kinetic melting of the samples. The EC-oleogel increased the elastic modulus of the cheese, while BW and CW decreased the elastic modulus, resulting in more viscous properties at lower temperatures. Further investigation into the oleogels independent from the plant-based cheese matrix was explored. The oleogels decreased the emulsion stability, suggesting emulsion stabilization is not predictive of oil stability in plant-based cheese. The oleogels also influenced the hardness and crystallinity of coconut oil, where EC-coconut oil displayed earlier crystal nucleation and its microstructure had a higher box-counting fractal dimension. Wax oil gelators had a more significant influence on coconut oil viscosity at lower temperatures than EC. Overall, oil loss modulation was achieved by changing coconut oil crystal network microstructure at low incorporation of oil gelators.
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•Oil loss in high-protein plant-based cheese can be reduced by adding oleogelators to coconut oil at low concentrations.•Oleogelators do not influence the melt and stretch properties of high-protein plant-based cheese.•Oleogelators can change the mechanical properties and microstructure of coconut oil.•Combination of viscosity enhancing and crystallization enhancing oil gelators provide the best oil modulation properties.
Animal-based food products, such as meat and dairy, contribute the most to greenhouse gas emissions in the food sector. This, coupled with the demonstrably worsening climate crisis, means that there ...needs to be a shift to more sustainable alternatives in the form of plant-based foods. In particular, the plant-based cheese alternative industry is relevant, as the products lack critical functionalities and nutrition compared to their dairy-based counterparts. Waxy starch, plant-protein isolate, and coconut oil were combined to create a novel high-protein (18% w/w) plant-based cheese alternative. We determined that when using native waxy starch, we can enhance its existing viscoelastic properties by modulating gelatinization through adding plant protein and fat. Texture profile analysis indicated that the cheese analogues could reach hardness levels of 15-90N, which allowed samples to be tailored to a broader range of dairy products. We determined that plant proteins and fat can behave as particulate fillers, enhance network strength, and create strategic junction points during starch retrogradation. The degree of melt and stretch of the high-protein plant-based analogues were 2-3 times greater than those observed for commercial plant-based cheese alternatives and significantly more similar to dairy cheese. The rheological melting kinetics saw that the high-protein plant-based cheese alternative displayed more viscous properties with increasing temperature. Tan δ (G"/G') at 80 °C was used as an indicator for sample meltability where, values ≥1 indicate better melt and more viscous systems. The high-protein plant-based cheese alternative reached Tan δ values upwards to 0.7, whereas commercial plant-based cheese alternatives only reached tan δ values around 0.1. Ultimately, the novel high-protein plant-based cheese alternative demonstrates the use of simple ingredients to form complex food systems.
