Comparative evaluation of structured oil systems: Shellac oleogel, HPMC oleogel, and HIPE gel

Preparation of soybean protein isolate-ester emulsifier oleogels and comparative study of their structure and properties

In recent years, oleogel as a viscoelastic semi-solid to replace trans fatty acids and reduce saturated fatty acids in food has received more and more attention. Herein, an emulsion template method was used to produce soybean oil-based oleogels with seven different ester emulsifiers and soy protein isolate as oleogelators. The chemical and physical characteristics of oleogels produced via various crosslinking factors were comparatively examined. Results revealed that all oleogels generated β-type needle crystals and exhibited high oil-holding capacity (>80 %), among which glycerol monolaurate G2 and diacetyl tartaric acid ester of mono-diglycerides G6 exhibited the strongest oil-holding capacity (96.6 % and 96.2 %, respectively). Furthermore, all oleogels exhibited strong thixotropic recovery, high thermal stability, as well as high gel strength (G' > G''). Of these, G2 and G6 exhibited the highest thixotropic recovery rates at 74.54 % and 78.19 %, respectively. Additionally, in accelerated oxidation trials, the peroxide value and thiobarbituric acid reactive substances of all oleogels had low oxidation rates, indicating high oxidative stability. These results contribute to a better understanding of oleogels for formulating trans-free and low-saturated foodstuffs with desired physical and functional properties.

Rapeseed oleogels based on monoacylglycerols and methylcellulose hybrid oleogelators: Physicochemical and rheological properties

In this study, we investigated the combined impact of monoacylglycerol (MAGs) and methylcellulose (MC) on the production of hybrid oleogels. Since cellulose derivatives are inherently hydrophilic substances, they require dissolution in oil through an emulsion-coating method. Therefore, we developed a hybrid oleogel utilizing MAGs and MC. Initially, a hybrid oleogelator was created by blending an aqueous MC solution into fully melted MAGs to form MC in water-in-MAGs emulsions with varying MC/MAG ratios, followed by drying. Subsequently, the resulting oleogelator was mixed with rapeseed oil to produce oleogels, and their properties were compared with oleogels produced solely with MAG oleogelator. The findings indicated that the obtained oleogelator did not significantly impact the oxidation of the oleogels. Additionally, there was no notable difference observed in the induction period of crystallization and the crystallization rate of the oleogels. Microscopic images revealed that the hybrid oleogel structured with a 30:70 ratio of MAGs and MC contained the lowest liquid phase percentage. In terms of rheological assessment, the hybrid oleogels exhibited solid-like behavior, consistent with polarized light microscopy (PLM) images. Furthermore, based on the three-interval thixotropic test (3-ITT), the hybrid oleogels displayed higher recovery compared to the control sample.

Replacing the animal fat in Bologna sausages using high internal phase emulsion stabilized with lentil protein isolate (Lens culinaris)

High internal phase emulsions (HIPEs) are promising techniques that can replace saturated fat in food without reducing the product's texture, sensory attributes, water-holding capacity, and cooking loss. In the current investigation, 100% pork back fat was replaced by HIPEs formed with lentil protein isolate (LPI) in Bologna sausages. HIPEs were prepared by 25% LPI dispersion (2, 4, 6, and 8%, w/w) and 75% (w/w) soybean oil. HIPEs with higher LPI concentration (4, 6, and 8%, w/w) showed lower droplet size, firmer appearance, and better rheology behavior than 2% LPI. The concentrations LPI (2%, 4%, 6%, and 8%, w/w) led to increased moisture in sausages (FH2, FH4, FH6, and FH8, respectively) compared to the FC. These LPI levels resulted in sausage values for pressed juice similar to the FC and lower energy values than sausages with soybean oil (FO) and pork back fat (FC). Besides, these LPI concentrations (4%, 6%, and 8%, w/w) resulted in a lower oil oxidation level in sausages with HIPEs (FH4, FH6, and FH8, respectively) compared to the control sausage formulation with pork back fat (FC). Bologna sausages elaborated with HIPEs showed emulsion stability values higher than 97%, without significance difference between them. The texture and sensory properties of sausages made with HIPEs were comparable to those made with pork back fat. HIPEs may improve the oxidation stability of the Bologna sausages. These results highlight the effectiveness of HIPEs structured with lentil protein in successfully substituting pork back fat in Bologna sausages with a better nutritional appeal.

Agar-gelatin Maillard conjugates used for Pickering emulsion stabilization

A few protein- and polysaccharide-based particles have shown promising potential as stabilizers in multi-phase food systems. By incorporating polymer-based particles and modifying the wettability of colloidal systems, it is possible to create particle-stabilized emulsions with excellent stability. A Pickering emulsifier (AGMs) with better emulsifying properties was obtained by the Maillard reaction between acid-hydrolysed agar and gelatin. Laser confocal microscopy imaging revealed that AGMs particles can be used as solid emulsifiers to produce a typical O/W Pickering emulsion, with AGMs adsorbing onto the droplet surface to form a dense interfacial layer. Cryo-scanning electron microscopy analysis showed that AGMs self-assembled into a three-dimensional network structure, which prevented droplets aggregation through strong spatial site resistance, contributing to emulsion stabilization. These emulsions exhibited stability within a pH range of 1 to 11, NaCl concentrations not exceeding 300 mM, and at temperatures below 80 °C. The most stable emulsion oil-water ratio was 6:4 at a particle concentration of 0.75 % (w/v). AGMs-stabilized Pickering emulsion was utilized to create a semi-solid mayonnaise as a replacement for hydrogenated oil. Rheological analysis demonstrated that low-fat mayonnaise stabilized with AGMs exhibited similar rheological behavior to traditional mayonnaise, offering new avenues for the application of Pickering emulsions in the food industry.

Raman spectroscopy and molecular dynamics simulations of protein microgels at the oil-water interface

The real-time structural changes of the molecular space conformation of myofibrillar protein microgels (MPM) after heat treatment (90 °C, 30 min) were analyzed by molecular dynamics simulation, and the structural properties and changes of MPM at the oil-water interface were analyzed by the combination of Raman spectroscopy and molecular dynamics simulation. The shift in the oil ratio had a major impact on the transformation of disulfide bonds within the protein molecule. Simultaneously, it caused tryptophan and tyrosine residues (I850 cm-1/ I850 cm-1 > 1) to become exposed, increasing the locations of amino acid residues in the protein that interact with the oil phase. HIPE with different oil phases influenced the change in spatial structural conformation of MPM, and there was a flexible structural change in the molecular space. The HIPE system, which was stabilized by 3.0 wt% MPM and 0.75 oil phase, exhibited a thixotropic recovery of >70 % and the highest elastic modulus G' (822.14 Pa) based on the rheological behavior. It is expected to provide a theoretical basis for the development and utilization of high internal phase emulsion stabilized by microgel protein in food industry.

Effect of different gelators on the physicochemical properties and microstructure of coconut oleogels

BACKGROUND

The inherent properties of coconut oil (CO), including its elevated saturated fatty acid content and low melting point, make it suitable for application in plastic fat processing. The present study explores the physicochemical characteristics, micromorphology and oxidative stability of oleogels produced from CO using various gelators [ethylcellulose (EC), β-sitosterol/γ-oryzanol (PS) and glyceryl monostearate (MG)] to elucidate the formation mechanisms of coconut oleogels (EC-COO, PS-COO and MG-COO).

RESULTS

Three oleogel systems exhibited a solid-like behavior, with the formation of crystalline forms dominated by β and β'. Among them, PS-COO exhibited enhanced capability with respect to immobilizing liquid oils, resulting in solidification with high oil-binding capacity, moderate hardness and good elasticity. By contrast, MG-COO demonstrated inferior stability compared to PS-COO and EC-COO. Furthermore, MG-COO and PS-COO demonstrated antioxidant properties against CO oxidation, whereas EC-COO exhibited the opposite effect. PS-COO and EC-COO exhibited superior thermodynamic behavior compared to MG-COO.

CONCLUSION

Three oleogels based on CO were successfully prepared. The mechanical strength, storage modulus and thermodynamic stability of the CO oleogel exhibited concentration dependence with increasing gelling agent addition. PS-COO demonstrated relatively robust oil-binding capacity and oxidative stability, particularly with a 15% PS addition. This information contributes to a deeper understanding of CO-based oleogels and offers theoretical insights for their application in food products. © 2024 Society of Chemical Industry.

Construction of a pectin/sodium alginate composite hydrogel delivery system for improving the bioaccessibility of phycocyanin

In this study, different concentrations of sodium alginate were compounded with pectin and phycocyanin to co-prepare composite hydrogel spheres (HP-PC-SA 0.2 %, 0.6 %, 1.0 %, 1.4 %) to evaluate the potential of the composite hydrogel spheres for the application as phycocyanin delivery carriers. The hydrogel spheres' physicochemical properties and bioaccessibility were assessed through scanning electron microscopy, textural analysis, drug-carrying properties evaluation, and in vitro and in vivo controlled release analysis in the gastrointestinal environment. Results indicated that higher sodium alginate concentrations led to smaller pore sizes and denser networks on the surface of hydrogel spheres. The textural properties of hydrogel spheres improved, and their water-holding capacity increased from 93.01 % to 97.97 %. The HP-PC-SA (1.0 %) formulation achieved the highest encapsulation rate and drug loading capacity, at 96.87 % and 6.22 %, respectively. Within the gastrointestinal tract, the composite hydrogel's structure significantly enhanced and protected the phycocyanin's digestibility, achieving a bioaccessibility of up to 88.03 %. In conclusion, our findings offer new insights into improving functionality and the effective use of phycocyanin via pectin-based hydrogel spheres.

Recent Advances in Lipid Crystallization in the Food Industry

This review discusses fundamental concepts of fat crystallization and how various processing conditions such as crystallization temperature, cooling rate, and shear or agitation affect this process. Traditional methods used to process fats, such as the use of scraped surface heat exchangers, fractionation, and interesterification, are described. Parameters that affect fat crystallization in these systems, such as shear, crystallization temperature, type of fat, and type of process, are discussed. In addition, the use of minor components to induce or delay fat crystallization based on their chemical composition is presented. The use of novel technologies, such as high-intensity ultrasound, oleogelation, and high-pressure crystallization is also reviewed. In these cases, acoustic and high-pressure process parameters, the various types of oleogels, and the use of oleogelators of differing chemical compositions are discussed. The combination of all these techniques and future trends is also presented.

Does protein deamidation enhance rice protein concentrate's ability to produce and stabilize high internal phase emulsions?

Rice is one of the most consumed grains in the world. Rice protein has great nutritional value as a hypoallergenic protein and due to its high lysine content, a limiting amino acid in several other plant protein sources. However, rice protein has low solubility, hampering its use in many applications in the food industry. In this context, alkaline deamidation (0.5 h, 343 K, and pH 11) was applied to modify the protein structure of rice protein concentrate (RPC). After deamidation, two protein powders were produced: (i) one containing the whole protein fraction recovered after RPC deamidation (DT) and (ii) another containing only the soluble fraction recovered after RPC deamidation (DS). Protein dispersions were characterized by SDS-PAGE, zeta potential, solubility, surface hydrophobicity, and capacity to hold water and oil. RPC could not structure canola oil into a high internal phase emulsion (HIPE) due to its low solubility. DT and DS dispersions displayed solubility much higher than RPC and enabled the structuration of HIPEs with 75 % (w/w) canola oil and 25 % of DT or DS dispersions (2, 4, and 6 % w/w). HIPEs were characterized regarding particle size, microstructure, Turbiscan and oil loss stabilities, and rheological behavior for 60 days. Turbiscan analysis and oil loss measurements showed high stability, and the thixotropy tests showed high recovery in all HIPEs. Higher protein concentrations and DS dispersions produced HIPEs with smaller particle sizes. However, rheological measurements indicate that HIPEs produced with DT dispersions had better results, maintaining their structure over the 60 days. Furthermore, DT is cheaper to produce; therefore, DT 4 and 6 % w/w were the most promising for producing HIPEs. The HIPEs produced in this study displayed great potential as fat replacers.

A chromosome-level genome assembly of the forestry pest Coronaproctus castanopsis

As an important forestry pest, Coronaproctus castanopsis (Monophlebidae) has caused serious damage to the globally valuable Gutianshan ecosystem, China. In this study, we assembled the first chromosome-level genome of the female specimen of C. castanopsis by merging BGI reads, HiFi long reads and Hi-C data. The assembled genome size is 700.81 Mb, with a scaffold N50 size of 273.84 Mb and a contig N50 size of 12.37 Mb. Hi-C scaffolding assigned 98.32% (689.03 Mb) of C. Castanopsis genome to three chromosomes. The BUSCO analysis (n = 1,367) showed a completeness of 91.2%, comprising 89.2% of single-copy BUSCOs and 2.0% of multicopy BUSCOs. The mapping ratio of BGI, second-generation RNA, third-generation RNA and HiFi reads are 97.84%, 96.15%, 97.96%, and 99.33%, respectively. We also identified 64.97% (455.3 Mb) repetitive elements, 1,373 non-coding RNAs and 10,542 protein-coding genes. This study assembled a high-quality genome of C. castanopsis, which accumulated valuable molecular data for scale insects.

Natural oleogelators for the formulation of oleogels by considering their rheological and textural perspective; a review

A well-known method for reducing or swapping out undesirable and controversial fats in food is oleogelation. To quantify the effects of droplets-particle inclusion on the textural aspects of gelled systems, a thorough understanding of rheological behavior of oleogels (OGs) is necessary. Otherwise stated, a rational grasp of rheological characterization is essential for food development, optimization, and processing (when touching or putting food into the mouth, rheological flow qualities influence our perception). This narrative review primarily intends to investigate rheological and textural characteristics of various oleogelator-based OGs, such as operative connection between hardness, distortion, stresses, and rheological parameters like viscosity, elasticity, and viscoelasticity, as well as flow behavior and recovery. Expanding oleogelators concentration and synergistic interactions between them increase robustness and moduli values, as compared to single oleogelators. However, given the lack of information on the connection between the OGs' macroscopic rheological characteristics and their microstructural characteristics, this review presents state-of-the-art overview of various oleogelator-based OGs, highlighting the importance of structure-rheology relationships of OGs to provide advanced knowledge on the development of innovative OGs.

Synergistic formulation approach for developing pea protein and guar gum enriched olive oil-in-water emulsion gels as solid fat substitutes: Formulation optimization, characterization, and molecular simulation

This study aimed to optimize the formulation of olive oil-in-water (O/W) emulsion gels by incorporating Pea Protein (PP) and Guar Gum (GG) as alternative options for solid fats. The optimum rheological (consistency index, apparent viscosity, recovery) and texture (firmness) properties of the emulsion gels were obtained using a mixture of 2 % PP, 1 % GG, 60 % Olive Oil (OO), and 37 % Water (W). The blend of PP2/GG1 showed the highest results for recovery and firmness, 111.27 % and 33.89 g, respectively. PP/GG blend emulsion gels exhibited higher absolute ζ-potential values, ranging between -72.3 and -77.4 mV. The polydispersity index (PDI) ranged from 0.185 to 0.535, with the most uniform distributions found in the PP/GG blend emulsion gels. Strong phase separation resistance indicated strong stability of PP-GG complex emulsion gels. Higher PP concentrations decreased emulsion oxidation. FTIR and XRD research showed that PP and GG interact strongly, indicating good compatibility. The free binding energy of the most stable configuration of the molecules was -6.8 kcal mol-1, indicating a high affinity. PP interacted with GG through 9 amino acid residues, with notable residues being Asp 224, Thr 235, Ala 332, Ile 334, and Arg 336, and their respective interaction distances ranged between 2.69 Å and 3.87 Å.

Edible polysaccharide-based oleogels and novel emulsion gels as fat analogues: A review

Polysaccharide-based oleogels and emulsion gels have become novel strategies to replace solid fats due to safe and plentiful raw material, healthier fatty acid composition, controllable viscoelasticity, and more varied nutrition/flavor embedding. Recently, various oleogelation techniques and novel emulsion gels have been reported further to enrich the potential of polysaccharides in oil structuring, in which a crucial step is to promote the formation of polysaccharide networks determining gel properties through different media. Meanwhile, polysaccharide-based oleogels and emulsion gels have good oil holding, nutrient/flavor embedding, and 3D food printability, and their applications as fat substitutes have been explored in foods. This paper comprehensively reviews the types, preparation methods, and mechanisms of various polysaccharide-based oleogels and emulsion gels; meanwhile, the food applications and new trends of polysaccharide-based gels are discussed. Moreover, some viewpoints about potential developments and application challenges of polysaccharide-based gels are mentioned. In the future, polysaccharide-based gels may be flexible materials for customized nutritional foods and molecular gastronomy. However, it is still a challenge to select the appropriate oleogels or emulsion gels to meet the requirements of the products. Once this issue is addressed, oleogels and emulsion gels are anticipated to be used widely.

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.

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.

Konjac glucomannan promoted fabrication of diacylglycerol oil-based oleogels through emulsion-templated approach: Comparison with triacylglycerol oleogels

Konjac glucomannan (KGM) combined with hydroxypropyl methyl cellulose was used to fabricate diacylglycerol oleogels (DGOs) through the emulsion-templated method, and compared with triacylglycerol oleogels (TGOs). The appearance and microstructure results showed that stable emulsions and oleogels could be formed in the presence of 0.2-0.6 wt% KGM. Higher KGM concentrations resulted in a stronger gel structure in oleogels, whose thixotropic recovery percentages were 50.45-75.20 %. From LF-NMR determination, the higher concentration of KGM presented earlier transverse relaxation (T2) time, and the T2 parameters of DGOs were higher than that of TGOs. Texture and oil loss analysis indicated that the mechanical strength and oil holding ability of DGOs were slightly lower than those of TGOs. This study demonstrated the advantages of biopolymers as thickening agents for obtaining stable emulsion and oleogels. The specific characteristics of DGOs distinguished from TGOs should be attributed to their different properties (unsaturation, viscosity, polarity, etc.) between the liquid oils.

The freeze-thaw stability of flavor high internal phase emulsion and its application to flavor preservation and 3D printing

Volatilization of flavor substances may reduce consumers' perception of flavor, and the research on preservation of flavor substances by high internal phase emulsions (HIPEs) under freeze-thaw conditions is still blank. Herein, flavor HIPEs prepared by adding more than 15% litsea cubeba oil in the oil phase could be used as food-grade 3D printing inks, and showed better stability after 5 freeze-thaw cycles, which could be interpreted as the reduced ice crystal formation, more stable interface layer, and more flexible gel-like network structure resulting from the protein binding to flavor substances. The constructed HIPEs system in this study could preserve the encapsulated flavor substances perfectly after 5 freeze-thaw cycles. Overall, this study contributes a food-grade 3D printing ink, and provides a new method for the preservation of flavor substances under freezing conditions and expands the application range of flavor HIPEs in food industry.

Flaxseed Gum/Arabic Gum/Tween 80-Based Oleogel as a Fat Substitute Applied in Emulsified Sausage: Physicochemical Properties, Sensory Attributes and Nutritional Quality

In the present study, flaxseed gum (FG), Arabic gum (GA) and Tween 80 were used to prepare oleogels through an emulsion-templated method, and the obtained oleogels were designed for the partial substitution of pork fat in emulsified sausage. An increment in FG concentrations enhanced the viscoelasticity of emulsions, which resulted in the improved stability of emulsion systems, with smaller droplet sizes. In addition, increased FG concentrations contributed to higher mechanical strength, denser network structure and lower oil loss of oleogels. As a fat substitute, the prepared oleogels improved the textural properties and nutritional quality of emulsified sausages. With the increase in the substitution level of oleogels, the hardness and chewiness of the emulsified sausage increased, and the cooking loss decreased. Meanwhile, the reformulation with oleogels decreased the saturated fat from 57.04 g/100 g lipid to 12.05 g/100 g lipid, while increasing the ratio of omega-6 to omega-3 essential fatty acids from 0.10 to 0.39. The obtained results demonstrated that the flaxseed gum/Arabic gum/Tween 80-based oleogels had huge potential to successfully replace pork fat in emulsified sausage products.

Improvement of 3D white chocolate printing molding effect with oleogels

This study used oleogels to resolve unsolidified white chocolate in 3D printing. Because white chocolate cannot be shaped during 3D printing, the oleogel system is used to solve this problem. The printing parameters and accuracy in a 3D printing system were investigated by using different oleogels added to white chocolate as a material to enhance chocolate extrusion solidification, monoglycerides (MAG), sucrose fatty acid ester (SE) and hydroxypropyl methylcellulose (HPMC), and their effects on rheological characterization, bridging experiments, and optimal print parameters (material formulation, nozzle height, layer height and print speed) were compared. In the rheological analysis, the viscosity recovery was more than 80% for the HPMC group and less than 80% for the MAG and SE groups. In the bridging experiment, when MAG and SE were added at more than 2%, the white chocolate could be effectively extruded and solidified, and the bridging distance could be stretched to 10 mm. The suitable printing parameters are a nozzle height of 3 mm, a layer height of 3 mm, and a printing speed of 10 mm/s. This study provides a future solution to solve the problem of extruded unsolidified chocolate.

Plant-based foods as meat and fat substitutes

Animal proteins have in the past been used in food production due to their functional properties that range from gelation and emulsification to foaming ability and stability. However, animal husbandry has been shown to be a major contributor to global warming and climate change. Consequently, there has been a drive toward the use of alternative proteins, for example, proteins from plant sources which are perceived to be cheaper, healthier, and sustainable. The use of trans and saturated fatty acids in the food industry has been associated with various health issues that include an increased risk of metabolic disorders. This has resulted in an increased search for fat substitutes that are healthier and sustainable. To contribute toward a reduction in the consumption of meats from animal sources and the consumption of trans and saturated fatty acids, the formulation of plant-based meat and fat analogs/substitutes has been carried out. However, there has been a lower acceptance of these meat or fat substitutes which was attributed to their sensorial and textural properties that fail to mimic or resemble real fat or meat. Therefore, this review aims to discuss the advances that have been made when it comes to plant-based meat and fat substitutes. Additionally, consumer perception and acceptance of these products will be reviewed as well as future markets will be discussed and the opportunities and challenges that exist in the formulation of these products will be explored.

Self-Healing Oxalamide Organogelators of Vegetable Oil

The aim of this study was to assess the gelling potential of chiral oxalamide derivatives in vegetable oils. Special emphasis was given to the potential applications of the examined oil gels as sustained delivery systems and as fat substitutes in food products. The applicability of oil gelators is envisaged in food, cosmetics, and the pharmaceutical industry. The regulations requiring the elimination of saturated fats and rising concerns among consumers health motivated us to investigate small organic molecules capable of efficiently transforming from liquid oil to a gel state. The oxalamide organogelators showed remarkable gelation efficiency in vegetable oils, thermal and mechanical stability, self-healing properties, and a long period of stability. The physical properties of the gels were analysed by TEM microscopy, DSC calorimetry, and oscillatory rheology. The controlled release properties of acetylsalicylic acid, ibuprofen, and hydrocortisone were analysed by the LC-MS method. The influence of the oil type (sunflower, soybean, and olive oil) on gelation efficiency of diverse oxalamide derivatives was examined by oscillatory rheology. The oxalamide gelators showed thermoreversible and thixotropic properties in vegetable oils with a minimum gelation concentration of just 0.025 wt%. The substitution of palm fats with gelled sunflower oil applied in cocoa and milk spreads at gelator concentrations lower than 0.2 wt% have shown promising viscoelastic properties compared to that of the original food products.

A review of oleogels applications in dairy foods

The characteristics of dairy products, such as texture, color, flavor, and nutritional profile, are significantly influenced by the presence of milk fat. However, saturated fatty acids account for 65% of total milk fat. With increased health awareness and regulatory recommendations, consumer preferences have evolved toward low/no saturated fat food products. Reducing the saturated fat content of dairy products to meet market demands is an urgent yet challenging task, as it may compromise product quality and increase production costs. In this regard, oleogels have emerged as a viable milk fat replacement in dairy foods. This review focuses on recent advances in oleogel systems and explores their potential for incorporation into dairy products as a milk fat substitute. Overall, it can be concluded that oleogel can be a potential alternative to replace milk fat fully or partially in the product matrix to improve nutritional profile by mimicking similar rheological and textural product characteristics as milk fat. Furthermore, the impact of consuming oleogel-based dairy foods on digestibility and gut health is also discussed. A thorough comprehension of the application of oleogels in dairy products will provide an opportunity for the dairy sector to develop applications that will appeal to the changing consumer needs.

Sucrose Esters as Oleogelators in Mono or Binary Structured Oleogels Using Different Oleogelation Routes

Sucrose esters (SE) have been investigated as structuring agents in oleogels. Due to the low structuration power of SE as single agent, this component has recently been explored in combination with other oleogelators to form multicomponent systems. This study aimed to evaluate binary blends of SEs with different hydrophilic-lipophilic balances (HLBs) with lecithin (LE), monoglycerides (MGs) and hard-fat (HF), according to their physical properties. The following SEs, SP10-HLB2, SP30-HLB6, SP50-HLB11, and SP70-HLB15, were structured using three different routes: "traditional", "ethanol" and "foam-template". All binary blends were made using a 10% oleogelator in 1:1 proportion for binary mixtures; they were then evaluated for their microstructure, melting behavior, mechanical properties, polymorphism and oil-binding capacity. SP10 and SP30 did not form well-structure and self-standing oleogels in any combination. Although SP50 showed some potential blends with HF and MG, their combination with SP70 led to even more well-structured oleogels, with a higher hardness (~0.8 N) and viscoelasticity (160 kPa), and 100% oil-binding capacity. This positive result might be attributed to the reinforcement of the H-bond between the foam and the oil by MG and HF.

Oleogels as a Fat Substitute in Food: A Current Review

Fats and oils in food give them flavor and texture while promoting satiety. Despite the recommendation to consume predominantly unsaturated lipid sources, its liquid behavior at room temperature makes many industrial applications impossible. Oleogel is a relatively new technology applied as a total or partial replacement for conventional fats directly related to cardiovascular diseases (CVD) and inflammatory processes. Some of the complications in developing oleogels for the food industry are finding structuring agents Generally Recognized as Safe (GRAS), viable economically, and that do not compromise the oleogel palatability; thus, many studies have shown the different possibilities of applications of oleogel in food products. This review presents applied oleogels in foods and recent proposals to circumvent some disadvantages, as reaching consumer demand for healthier products using an easy-to-use and low-cost material can be intriguing for the food industry.

Oleogels-Innovative Technological Solution for the Nutritional Improvement of Meat Products

Food products contain important quantities of fats, which include saturated and/or unsaturated fatty acids. Because of a proven relationship between saturated fat consumption and the appearance of several diseases, an actual trend is to eliminate them from foodstuffs by finding solutions for integrating other healthier fats with high stability and solid-like structure. Polyunsaturated vegetable oils are healthier for the human diet, but their liquid consistency can lead to a weak texture or oil drain if directly introduced into foods during technological processes. Lately, the use of oleogels that are obtained through the solidification of liquid oils by using edible oleogelators, showed encouraging results as fat replacers in several types of foods. In particular, for meat products, studies regarding successful oleogel integration in burgers, meat batters, pâtés, frankfurters, fermented and bologna sausages have been noted, in order to improve their nutritional profile and make them healthier by substituting for animal fats. The present review aims to summarize the newest trends regarding the use of oleogels in meat products. However, further research on the compatibility between different oil-oleogelator formulations and meat product components is needed, as it is extremely important to obtain appropriate compositions with adequate behavior under the processing conditions.

The Feasibility of Shellac Wax Emulsion Oleogels as Low-Fat Spreads Analyzed by Means of Multidimensional Statistical Analysis

Shellac wax-based oleogel emulsions were studied with a three level two factorial design in order to find an optimal formulation for a spread formulation. Rheological, textural, colorimetry, and stability analysis were conducted to assess the performance of oleogel emulsions. FTIR spectra were also compared. The similarities between the samples were studied using cluster analysis. Analysis of variance (ANOVA) demonstrates that (i) the texture is influenced by the wax concentration, (ii) the rheology and stability by both the considered numeric factors (wax and water concentration) and their interaction, and (iii) the color by both factors. The emulsions containing 7% (m/m) shellac oleogels behaved like the strongest systems, (G′ & GLVR > 30,000 Pa) and exhibited the highest value of the G′-G″ cross-over. The lowest oil binding capacity (OBC) was 99.88% for the sample with 3% (m/m) shellac and 20% (m/m) water. The whiteness index (Windex) varied between 58.12 and 78.50. The optimization process indicated that a formulation based on 4.29% (m/m) shellac wax and 24.13% (m/m) water was suitable as a low-fat spread.

Gel Properties and Formation Mechanism of Camellia Oil Body-Based Oleogel Improved by Camellia Saponin

This study aimed to investigate the effect of camellia saponin (CS) on the structural characteristics, texture properties, rheological properties, and thermal stability of camellia oil body-based oleogel (COBO). In addition, the formation mechanism of COBO was further studied in terms of the microstructure and texture of freeze-dried products, the mobility of hydrogen protons, and the conformation and structure changes of oleosin. The texture and rheological properties of the oleogels were found to be gradually improved with the incorporation of CS. This was attributed to the CS-induced enhancement of oil body interfacial film. CS was likely to bind to oleosin via hydrogen bonding and hydrophobic interactions, thereby forming a thick CS-oleosin complex interface, which was revealed by the oleosin fluorescence quenching and an increase in the ordered structure (α-helix). The composite interface could resist the crystallization damage and air disturbance caused by solidification and sublimation of water during freeze-drying, resulting in a denser and more uniform three-dimensional gel structure to trap the liquid oil, which could be explained by the decreased mobility of hydrogen protons in oleogel. The work offers a new proposal and theoretical basis for the development of saponin-enhanced oleogels using non-thermal processing.

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

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

Fabrication and characterization of oleogels and temperature-responsive water-in-oil emulsions based on candelilla (Euphorbia cerifera) wax

Developing novel fats with zero trans and low saturated fatty acids represents a research hotspot in the colloid field today. Herein, natural candelilla (Euphorbia cerifera) wax was used as an oleogelator to construct oleogel systems, and can make strong oleogels at low concentrations (3 wt%). These oleogels were further employed as continuous phases to fabricate surfactant-free W/O emulsions with excellent stability (at least 30 days). Microstructural observation confirmed that the stability of emulsions was attributed to the interface and bulk phase crystallization of wax. All oleogels and emulsions were pseudoplastic fluids whose gel properties could be tuned via regulating oleogelator concentration. Water content also influenced the emulsion rigidity, denoting the droplets acted as "active fillers". Additionally, the emulsions displayed a temperature-responsive property, beneficial in mimicking the "fat-like" melt-in-the-mouth effect. These findings greatly enrich the formulation of surfactant-free W/O emulsions, providing technical support for the development of novel fats.

Self-Healing Chitosan Hydrogels: Preparation and Rheological Characterization

The paper aims at the preparation of chitosan self-healing hydrogels, designed as carriers for local drug delivery by parenteral administration. To this aim, 30 hydrogels were prepared using chitosan and pyridoxal 5-phosphate (P5P), the active form of vitamin B6 as precursors, by varying the ratio of glucosamine units and aldehyde on the one hand and the water content on the other hand. The driving forces of hydrogelation were investigated by nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction, and polarized light microscopy (POM) measurements. NMR technique was also used to investigate the stability of hydrogels over time, and their morphological particularities were assessed by scanning electron microscopy (SEM). Degradability of the hydrogels was studied in media of four different pH, and preliminary self-healing ability was visually established by injection through a syringe needle. In-depth rheological investigation was conducted in order to monitor the storage and loss moduli, linear viscoelastic regime, and structural recovery capacity. It was concluded that chitosan crosslinking with pyridoxal 5-phosphate is a suitable route to reach self-healing hydrogels with a good balance of mechanical properties/structural recovery, good stability over time, and degradability controlled by pH.

Observation of curcumin-loaded hydroxypropyl methylcellulose (HPMC) oleogels under in vitro lipid digestion and in situ intestinal absorption in rats

Curcumin-loaded nanostructured lipid carriers (Cur-NLCs)-based hydroxypropyl methylcellulose (HPMC) oleogels (Cur-NLCs-HPMC-OGs) were fabricated using a cryogel template. The effect of the HPMC viscosity grade on the oleogel characteristics and in situ intestinal absorption were examined. Highly stable Cur-NLCs were prepared with a mean particle size of 314 nm and polydispersity index of 0.275. Cur-NLCs affected the creamy texture of self-standing Cur-NLCs-HPMC-OGs. The Cur-NLCs were tightly packed as oil droplets in the network of HPMC. However, a high viscosity of HPMC-4000 led to a greater ability to entrap and prevent droplet coalescence compared to a low viscosity of HPMC-400. NLCs promoted the release of free fatty acids during in vitro lipid digestion, whereas HPMC-4000 maintained the strength and durability of oleogels against mechanical and enzymatic breakdown. The in situ loop results revealed higher curcumin absorption by Cur-NLCs-HPMC-OGs than by Cur-HPMC-OGs. HMPC-4000 showed slightly higher curcumin absorption compared to HPMC-400.

The role of nanostructured lipid carriers and type of biopolymers on the lipid digestion and release rate of curcumin from curcumin-loaded oleogels

Curcumin-nanostructured lipid carrier-loaded oleogels (Cur-NLC-OGs) have been developed with biopolymer cryogels as an efficient delivery system to overcome the extremely low water solubility and instability of curcumin. The effect of NLC and biopolymer types on the encapsulation and release of curcumin from Cur-OGs was investigated. Alginate, carboxymethyl cellulose (CMC), and pectin solutions were firstly freeze dried to make biopolymer cryogels and they were mixed with Cur and Cur-NLC to obtain stable and self-standing Cur-OGs and Cur-NLC-OGs, respectively. As compared to Cur-OGs, Cur-NLC-OGs had higher encapsulation efficiency and showed slower release of curcumin under acidic condition. Although Cur-NLC affected the rapid release of free fatty acids, the Cur-NLC-OGs prepared with CMC cryogel was most efficient in delaying lipid digestion. Overall, NLC and CMC-based OGs could be effectively used to improve encapsulation efficiency and control lipolysis of lipid droplets. These results will be advantageous for the development of oleogels with desirable functionality.

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.

Thermo-rheological properties of chitosan hydrogels with hydroxypropyl methylcellulose and methylcellulose

Thermal and rheological properties of methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) hydrogels with chitosan (CHI) were investigated to verify the potential application of these blends as structured systems for oil transport (emulgel, oleogels, and bigels). FTIR confirmed hydrophobic interactions of cellulosic polymers with chitosan. In the temperature sweep, the thermosensitive hydrogels showed their reduced gel point compared to the original polymers. The gelation temperature was reduced from 66.9 °C for pure HPMC to 43.6 °C and 43.6 °C (MC pure polymer) to 39.3 °C when 30% CHI was added for both cases. The addition of 20 and 30% chitosan is enough to modify the extension of the gelation temperature of these polymers. These results indicate that the addition of chitosan enables MC and HPMC to form gels at lower temperatures, which could allow milder thermal conditions to be applied in processing oil carrier systems.