A critical review on structures, health effects, oxidative stability, and sensory properties of oleogels

Effects of antioxidants on the oxidative stability of expeller-pressed high oleic soybean oil (EPHOSO) oleogel and cookie

In this study, green tea extract (GTE) and/or ethylenediaminetetraacetic acid (EDTA) were incorporated into the expeller-pressed high oleic soybean oil (EPHOSO) oleogel and their antioxidative activity on the oleogel oxidation was investigated. Electron paramagnetic resonance (EPR) confirmed that heating EPHOSO at 90 °C for 30 min during oleogel preparation did not accelerate free radical formation. Moreover, the addition of GTE at 300 ppm significantly reduced the levels of both free radicals and lipid hydroperoxides, effectively extending the lag phase by 5 days. In contrast, EDTA at a lower concentration (75 ppm) was more efficient in preventing the formation of propanal than at a higher concentration (150 and 300 ppm). Synergistic effects were recorded in retarding free radicals and lipid hydroperoxides when 300 ppm of GTE and 75 ppm of EDTA was applied. Furthermore, replacing shortening with the oleogel significantly enhanced the oxidative stability of cookies, even without any antioxidants.

Effect of moisture loss on aroma profile, key odorants, and fatty acids of Amomum tsaoko during vacuum oven drying

The effects of vacuum oven drying at 60 °C on the aroma profile, key odorants, fatty acids, and chiral compounds of fresh Amomum tsaoko (AT) were evaluated over varying drying times. Quantitative descriptive analysis, solvent-assisted flavor evaporation, and gas chromatography-olfactometry-mass spectrometry identified and quantitated 36 odor-active compounds. Aldehydes, particularly geranial (1606-1809 mg/kg), were consistently prominent across all drying durations. Twenty-four key odorants with odor activity values greater than one were identified and screened. Relationships among seven samples, 24 key odorants, and six attributes were elucidated through orthogonal partial least squares-discriminant analysis. Notably, 13 odorants exhibited changes during the drying process, as indicated by variable importance for projection scores. Additionally, fatty acid analyses revealed that palmitic and oleic acids were predominant in AT. This study provides valuable insights into the impact of moisture loss on the key chemical components of AT, supporting the development of diverse consumer-oriented products.

Development and characterization of bigel systems as carriers for thyme essential oil utilizing hydrogel from chicken processing by-products for food applications

A chicken protein hydrogel (HG) was enzymatically prepared and blended with a carnauba wax-based oleogel (OG) to form bigels (BG) in ratios of 50:50 to 90:10. These systems were infused with thyme essential oil (TEO) at 0.5 %, 1 %, and 2 % v/v to harness its antioxidant properties. Polarized light microscopy revealed that carnauba wax crystals were tightly arranged in thin, plate-like structures, while the HG exhibited a completely amorphous form. FT-IR analysis indicated that OH bonds in the HG and CH bonds in cycloalkanes from the OG contributed to the stability and strength of the gels. Unlike the biphasic gels, both the OG and HG samples experienced structural disintegration when the applied strain reached approximately 30 %. HG samples, with an onset melting temperature of 59.18 °C, were particularly susceptible to thermal deformation, leading to coalescence and destabilization of the BG due to the HG phase in the composite matrix. Regardless of the TEO concentrations, the BG (50:50) demonstrated the highest water-holding capacity (60.83 %), and oil-binding capacity (99.23 %) compared to the single biopolymer gels. The lightness of the BG increased as the HG ratio increased. Additionally, the antioxidant capacity increased with higher TEO concentrations, demonstrating the gels' potential for food applications.

Consumption of oleogel alleviates lipid metabolism disorders in high-fat diet-fed rats by inhibiting LPS-induced gut microbiota-mediated inflammation

This study investigated the effect of oleogel consumption on lipid metabolism, gut microbiota and low-grade inflammation in rats fed with a high-fat diet. Male SD rats received either a control diet or high-fat diets for six weeks. The high-fat diets included a regular high-fat diet and high-fat diets in which lard was replaced with pure sunflower oil, un-gelled sunflower oil containing a dispersed gelator, or gelled sunflower oil with the gelator (oleogel). Results showed that compared to regular fat, pure sunflower oil and un-gelled sunflower oil consumption, oleogel consumption significantly suppressed weight gain and adipose tissue accumulation as well as serum and liver lipid accumulation. Microscopic observations further confirmed that oleogel intake alleviated white adipose tissue and liver steatosis caused by high-fat diet. Ex vivo biodistribution studies indicated an increased movement of TAGs toward the large intestine in the oleogel group. In the meantime, the dysregulation of gut microbiota was restored by reducing the Firmicutes/Bacteroidetes ratio and the relative abundance of Desulfobacterota and Proteobacteria. The oleogel group also exhibited reduced LPS levels in faeces, serum and liver. Furthermore, oleogel consumption alleviated inflammation, including decreased gene expression of pro-inflammatory cytokines, such as IL-6 and TNF-α, as well as suppressed protein expression of TLR4 and NF-κB in the liver. These results provide theoretical guidance for the regulation of oleogel properties and the potential application of oleogels as healthy fat replacers in high-fat diets.

Substitutes for Industrial Trans Fats in Packaged Foods: A Scoping Review

The World Health Organization recommended the global elimination of industrial trans fats by 2023, leading to a decrease in their use in packaged foods. Nevertheless, a gap remains in the scientific literature regarding the ingredients adopted as substitutes by the food industry. This study aimed to map evidence on substitutes for industrial trans fats in packaged foods, discussing their possible designation in the ingredients lists. For this, a scoping review was conducted according to recommendations from the Joanna Briggs Institute. Systematic searches were performed in 6 databases using terms related to industrial trans fats, identification of possible substitutes, and trans fats exemption. The search retrieved 5072 articles. Of these, 233 (152 original articles and 81 review studies) were included in the scoping review. A total of 87 different raw materials were cited as trans fats substitutes in the selected studies, with palm stearin being the most frequent. The processing methods were categorized in 8 groups, with interesterification being the most cited (46% of studies). Food items belonging to 15 food groups were found to contain trans fats substitutes, mainly margarine, shortenings, and spreads. From the collected data, it was estimated that there are at least 690 distinct terms for referring to industrial trans fats substitutes in the ingredients list. Despite the extensive body of research on the subject, the Codex Alimentarius guidelines and some national labeling regulations do not address the reporting of such materials in the ingredients lists. Furthermore, there is limited understanding of the short- and long-term effects of novel technological ingredients on human health. The disclosure of industrial processes to modify oils and fats, as well as the raw materials used, is suggested to be made mandatory in the ingredients list, aiming to safeguard consumers' right to information and enhance monitoring efforts.

A scalable and eco-friendly carbohydrate-based oleogelator for vitamin E controlled delivery

Supramolecular oleogels, in which low-molecular weight oleogelators self-assemble into various nanostructures through non-covalent interactions, have witnessed increasing research activity in various fields of science, including food, cosmetics or remediation of marine oil spills. Herein, we report a simple scalable and environmentally friendly carbohydrate-based oleogelator, namely, the sodium salt of N,N'-dimethyl β-C glucosyl barbiturate (GlcBMe) that self-assembles through sonication to induce the gelation of polar organic solvent and later of non-polar vegetable oils by cationic exchange with quaternary ammonium surfactants. Water-soluble GlcBMe was capable of forming self-assembled fibrillar network bridging insoluble particles in the oil by sonication in the presence of a small amount of water. The rheological properties are reinforced by in situ particle bridging with quaternary ammonium surfactants as evidenced by multi-scale structural analyses. IR analysis indicated that -OH (from carbohydrates) and -C[double bond, length as m-dash]O (from barbituric ring) were involved in hydrogen bonding promoting the formation of a fibrous network. The oleogel presented a non-Newtonian system showing a shear-thinning behavior and thixotropic properties. Advantageously, these oleogels showed excellent control and slow release of the loaded-vitamin E in a pH-dependent manner.

Valorization of Spent Coffee Grounds Oil for the Production of Wax Esters: Enzymatic Synthesis and Application in Olive Oil Oleogels

Spent coffee grounds, the main by-product of the coffee-brewing process, were valorized as a renewable source of lipids for the synthesis of novel wax esters and as an alternative and sustainable oil-structuring agent for the production of oleogels. The lipase-catalyzed reactions were implemented using fatty alcohols both under solvent-free conditions and with limonene as an environmentally friendly solvent. Wax esters were evaluated for their ability to formulate olive oil oleogels through the determination of the physical properties of oleogels. Results showed that high conversion yields were achieved when cetyl and behenyl alcohols were applied under solvent-free conditions, achieving a maximum yield of 90.3% and 91.7%, respectively. In the presence of limonene, the highest conversion yields were 88.9% and 94.5% upon the use of cetyl and behenyl alcohols, respectively. The behenyl wax esters exhibited greater oil-structuring properties, regardless of whether they were derived from solvent or solvent-free conditions. Rheological curves showed that the produced oleogels exhibited a strong gel strength, which was enhanced as the wax ester concentration increased. Frequency sweep curves confirmed the formation of a stable three-dimensional oleogel network and revealed the low dependence of the storage modulus on frequency. Overall, this study demonstrated that producing wax esters from renewable lipid sources has the potential to serve as an effective circular economy paradigm for creating novel oleogels with a broad range of applications.

Changing the horizon of food frying from the use of liquid oil to semi-solid gel

Deep fat frying is the most adopted process of producing fried food products; it involves mass and heat transfer to form fried products with good colour, crispiness, flavour, taste, and texture. However, frequent consumption of these products is a concern due to higher oil content that poses threats to human health. Hence, there is a need to find an alternative frying medium for deep fat frying of food products to obtain fried products having lower fat content. The structuring of liquid oil to convert it into semi-solid gel by the process of oleogelation forms oleogel. The use of oleogel as a frying medium gives fried products with good oxidative, textural, and sensory attributes. The Oleogelator used in the formulation of oleogel plays a significant role in maintaining the stability of oleogel. An increase in the oleo gelator concentration decreases the oil uptake in the fried product. The superior product quality and high consumer acceptance of oleogel fried products indicate that oleogel is a potential frying medium. The scope of the present review is to cover the heat and mass transfer perspective of the deep fat frying process, factors responsible for oil uptake in fried products, formulation and components of semi-solid system, discussion on various characteristics of semi-solid system as frying medium, comparative assessment of oil uptake in food fried in oleogel and conventional oil and finally covering specific examples showing the efficacy of liquid oil oleogel as a frying medium.

Structural Build-Up and Stability of Hybrid Monoglyceride-Triglyceride Oleogels

Oleogelation is an alternative oil structuring route to formulate (semi-)solid fats with a reduced amount of saturated fats. Monoglycerides have been identified as effective gelators; however, their application potential can be limited due to challenges regarding mechanical strength and long-term stability. Therefore, the formulation of hybrid fat blends is a promising way to improve the functionality of oleogels. This research focuses on the interaction between mono- and triglycerides (MAGs and TAGs) in hybrid oleogels. A total gelator concentration of 10% (w/w) with changing MAGs-TAGs ratios (increase by 25% on a molar basis; M0-T100, M25-T75, M50-T50, M75-T25, M100-T0) was used. First, the oleogels were produced without shear to unravel the crystallization behavior (DSC, SAXS, WAXS). Next, the oleogels were crystallized with shear to assess the interactions between MAGs and TAGs on macroscale properties (rigidity, oil binding capacity) during storage of 1 day, 1 week, and 4 weeks. A clear distinction could be made between the MAG crystals and TAG crystals in the blends M50-T50 and M75-T25 based on WAXS, SAXS, and phase contrast microscopy. This indicates that both gelators crystallize separately. During the follow-up study of the dynamically produced samples, a synergistic effect was found for Dy-M50-T50 and Dy-M75-T25; however, it was not maintained upon storage. The initial rigidity of 2.4 × 104 Pa and 2.0 × 104 Pa decreased to 1.5 × 104 Pa and 1.0 × 104 Pa for Dy-M50-T50 and Dy-M75-T25, respectively.

Effects of clove bud oil on the physicochemical properties and oxidative stability of canola oil organogels structured by different beeswax contents

The aim of this study was to investigate the utilization of clove bud oil as fat-soluble antioxidants for retarding lipid oxidation in organogels by structuring canola oil with beeswax at 5, 7.5, and 10% concentration under accelerated oxidation condition. Oil binding capacity and viscoelastic properties were increased with beeswax content, but were not nearly affected by the addition of clove bud oil. Organogel loaded with clove bud oil were found to be more effective in retarding lipid oxidation in high beeswax content systems, particularly evident in 10% beeswax samples. The addition of clove bud oil resulted in low levels of hyeoperxide and MDA, and protected against texture and color deterioration during the storage period. Additionally, the Pearson correlation between lipid oxidation indices and parameters of texture and color has been found to exhibit a limited association, with the exception of the a* and b* values, which show a strong correlation.

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.

Candelilla Wax and Glycerol Monostearate-Based Oleogels as Animal Fat Substitutes in Bologna Sausages

The aim of this study was to produce Bologna sausages rich in unsaturated fatty acids and to evaluate this replacement on the structural characteristics. For the purpose of a comparative analysis, three different types of sausages were produced, distinct only in the type of fat used: I. sausages obtained with pork backfat (PBF), II. sausages produced with oleogel formed from refined sunflower oil and glycerol monostearate (GM_OG), and III. with candelilla wax oleogel (CW_OG). The meat composition was also analyzed to better understand the process in the dynamics and the finished products were analyzed both uncooked and cooked. The enhanced oil-binding capacity of oleogels suggests their potential value as substitutes for saturated fats (>99%). In terms of meat composition textural analysis, the highest hardness value was registered for PBF_C of 25.23 N, followed by a CW_OG_C of 13.08 N and a GM_OG_C of 12.27 N. However, adhesiveness, cohesiveness, springiness index, and gumminess showed similar values between samples. Reformulation of products with oleogels as a fat source abundant in mono- and polyunsaturated fatty acids resulted in uncooked products exhibiting reduced hardness values of 49.01 N (CW_OG_US) and 40.51 N (GM_OG_US), compared to 65.03 N (PBF_US). Color results of the cross-section color can indicate the potential for consumer acceptance due to the reduced color differences between the conventional and oleogel samples.

The gelation characteristics of Torreya grandis wax in diacylglycerol and its preparation of oleogel substitution for shortening

Torreya grandis wax (TGW), a new nut wax and by-product of refined Torreya grandis oil, lacks sufficient research and application. In this study, the gelling behavior in diacylglycerol (DAG) and chemical compositions of TGW were investigated. Compared with four typical natural waxes, TGW exhibited the lowest critical gelling concentration (Cg, 1 %wt) in DAG. The results performed that TGW-DAG oleogels at Cg possessed the highest G'LVR and G″, highest critical stress, good thermal stability, moderate viscosity recovery, and osc. yields stress, indicating strong gel. The microstructure and correlation analysis revealed that excellent gelling behaviors of TGW-DAG oleogels were due to the solid three-dimensional network formed by rod-like TGW crystal, and the higher hydrocarbon compound (HC) content and HC/wax ester in TGW. Formulation optimization suggested that oleogel containing 3.2 % TGW and 1.0 % diosgenin (DSG) better mimicked the characteristics of shortening in terms of hardness, adhesiveness, spreadability. The bread prepared with TGW/DSG-DAG oleogel owned uniform and dense pores, the best moisture retention capability, and soft and firm taste, demonstrating that TGW/DSG-DAG oleogel was a good shortening substitute. Therefore, this study provides the systematically fundamental knowledge of TGW and develops DSG-TGW-DAG oleogels as promising shortening substitutions.

A novel edible solid fat substitute: Preparation of biphasic stabilized bigels based on glyceryl monolaurate and gellan gum

Solid fats contribute to a delicate and pleasant flavor for food, but its excessive intake increases the risk of cardiovascular disease. Bigel is considered a promising solid fat substitute as it significantly reduces fat content while meeting consumer demands for food flavor and a balanced diet. In this study, bigels were prepared by mixing glyceryl monolaurate-based oleogel (10 wt%) and gellan gum-based hydrogel (0.8 wt%) at ratios of 1:3, 1:1, and 3:1. The microscopic results indicated that the oleogel/hydrogel ratios influenced the structure of bigels, forming oil-in-water, bi-continuous, and water-in-oil bigels with the increase of oleogel proportion, respectively. All bigels presented a semi-solid structure dominated by elasticity, and their hardness, gumminess, chewiness, and cohesiveness increased with the enhancement of hydrogel proportion. Among them, the bigels (S25:L75 and S25:H75) prepared with an oleogel/hydrogel ratio of 1:3 showed excellent freeze-thaw stability, maintaining an oil holding capacity of >95 % after three freeze-thaw cycles. Meanwhile, they also presented good oxidative stabilities, where the peroxide values and malondialdehyde contents were below 0.07 g/100 g and 1.5 mg MDA/kg at 12 d, respectively. Therefore, S25:L75 and S25:H75 are expected to be green, low-cost, healthy, and sustainable alternatives to solid fats.

Microstructure, Physical Properties, and Oxidative Stability of Olive Oil Oleogels Composed of Sunflower Wax and Monoglycerides

The utilization of natural waxes to form oleogels has emerged as a new and efficient technique for structuring liquid edible oil into solid-like structures for diverse food applications. The objective of this study was to investigate the interaction between sunflower wax (SW) and monoglycerides (MGs) in olive oil oleogels and assess their physical characteristics and storage stability. To achieve this, pure SW and a combination of SW with MGs in a 1:1 ratio were examined within a total concentration range of 6-12% w/w. The formed oleogels were characterized based on their microstructure, melting and crystallization properties, textural characteristics, and oxidative stability during storage. All the oleogels were self-standing, and, as the concentration increased, the hardness of the oleogels also increased. The crystals of SW oleogels were long needle-like, while the combination of SW and MGs led to the formation of crystal aggregates and rosette-like crystals. Differential scanning calorimetry and FTIR showed that the addition of MGs led to different crystal structures. The oxidation results revealed that oleogels had low peroxide and TBARS values throughout the 28-day storage period. These results provide useful insights about the utilization of SW and MGs oleogels for potential applications in the food industry.

Lecithin's Roles in Oleogelation

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

Physicochemical properties of Pickering emulsion fabricated with polysaccharides/pea protein isolate complex and its application in plant-based patty

Incorporation of structured liquid oil within plant-based patties can be achieved through the utilization of food-grade Pickering emulsion (PE). Therefore, the aim of this study was to evaluate the quality characteristics of PE and its application in plant-based patty. The PEs were formulated using sunflower oil (SO), polysaccharides and protein, and the specific ratios employed were as following: methylcellulose (MC) 2 % only (MP0); MC 1.5 % + pea protein isolate (PPI) 0.5 % (MP1); MC 1 % + PPI 1 % (MP2); xanthan gum (XG) 2 % only (XP0); XG 1.5 % + PPI 0.5 % (XP1); XG 1 % + PPI 1 % (XP2). MP0 and MP1 were unstable as PEs, whereas MP2 and XP groups (XP0, XP1, and XP2) exhibited stability as a PE. In addition, MP2 and all XP groups showed increased oil binding capacity, hydrophobic interaction, thermal stability, crystallization, rheological properties, and oxidative stability, compared to MP0 and MP1. In PE-applied plant-based patties, MP2 and all XP groups had significantly lower cooking loss and higher emulsion stability than SO. Particularly, MP2-employed plant-based patties exhibited significantly improved textural and sensory properties. Therefore, our data suggest that PEs with methylcellulose and pea protein isolate could be an effective replacement of plant oil in plant-based meat analogs.

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

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

Bioaccessibility, Intestinal Absorption and Anti-Inflammatory Activity of Curcuminoids Incorporated in Avocado, Sunflower, and Linseed Beeswax Oleogels

Beeswax oleogels (OGs), with a mechanical strength similar to pork backfat, were formulated with avocado (A), sunflower (S), and linseed (L) oils, applying a central composite design plus star point, and were evaluated as oral delivery vehicles of curcuminoids (OGACur, OGSCur, OGLCur). The incorporation of curcumin into the OG matrix significantly delayed both the formation of peroxides and conjugated trienes (K268 values), and the degradation rate of curcumin decreased with the increase of the oil polyunsaturated fatty acids (PUFA) content. The oil structuring did not affect the bioaccessibility of curcuminoids (>55% in all the OGs, regardless of the oil type), but it did reduce the release of fatty acids (~10%) during in vitro gastrointestinal digestion. The intestinal absorption, evaluated in Caco-2 cell monolayers, was higher for the micelle-solubilized curcumin from the digested OG than from unstructured oils, and it showed high anti-inflammatory potential by inhibiting the tumor necrosis factor-α (TNF-α) production compared to the positive control, both before and after the stimulation of ThP-1 cells with LPS. Regardless of the oil type, these beeswax-based OGs with gel-like behavior designed as fat replacers may be promising vehicles for the oral delivery of curcuminoids.

Foam-templated oleogels constructed by whey protein isolate and xanthan gum: Multiple-effect delivery vehicle for Antarctic krill oil

To address the limitations of Antarctic krill oil (AKO) such as easy oxidation, unacceptable fishy flavor and low bioaccessibility of astaxanthin in it, a multiple-effect delivery vehicle for AKO is needed. In this study, whey protein isolate (WPI) and xanthan gum (XG) were utilized to construct AKO into oleogels by generating foam-templates. The effects of the concentration of XG on the properties of foam, cryogel and the corresponding oleogels were investigated, and the formation mechanism of oleogel was discussed from the perspective of the correlation between foam-cryogel-oleogel. The results demonstrated that with the increase of the concentration of XG, the foam stability was improved, the cryogel after freeze drying had a more uniform network structure and superior oil absorption ability, and the corresponding oleogel had excellent oil holding ability after oil absorption. The AKO oleogels showed superior oxidative stability compared with AKO. The in vitro digestion experiments demonstrated that the bioaccessibility of the astaxanthin in this oleogel was also considerably higher than that in AKO. In addition, this oleogel had masking effect on the odor-presenting substances in AKO, while retaining other flavors of AKO. The foam-templated oleogel can be considered as a multiple-effect vehicle for AKO to facilitate its application in food products. This study provides theoretical basis and data support for the development and utilization of novel vehicle for AKO, broadening the application of AKO in the field of food science.

Recent advances in natural gums as additives to help the construction and application of edible biopolymer gels: the example of hydrogels and oleogels

Novel, innovative approaches like edible gels (hydrogels and oleogels) are important food materials with great scientific interest due to their positive impacts on structural and functional foods and other unique properties. Biopolymers (protein, starch and other polysaccharides) can be excellent and cost-effective materials for the formed edible gels. Recently, natural gums, although also as biopolymers, are preferred as additives to further improve the textural and functional properties of edible gels, which have received extensive attention. However, these studies have not been outlined in previous reviews. In this review, we highlighted the advantages of gums as additives to construct edible gels. Moreover, the various roles (including electrostatic or covalent interactions) for natural gums in regulation of food gel properties (solvent-holding and rheological properties) are highlighted. Finally, the use of natural gums as additives to improve the stability and targeted delivery of phytochemicals in food gels and their application in food systems are summarized. The information covered in this article may be useful for the design of functional foods that can better meet personalized needs of people.

The oxidative quality of bi-, oleo- and emulgels and their bioactives molecules delivery

During recent years, the applicability of bi-, oleo- and emulgels has been widely studied, proving several advantages as compared to conventional fats, such as increasing the unsaturated fat content of products and being more sustainable for temperate regions as compared to tropical fats. Moreover, these alternative fat systems improve the nutritional profile, increase the bioavailability of bioactive compounds, and can be used as preservation films and markers for the inactivation of pathogens, while in 3D printing facilitate the obtaining of superior food products. Furthermore, bi-, oleo- and emulgels offer food industries efficient, innovative, and sustainable alternatives to animal fats, shortenings, margarine, palm and coconut oil due to the nutritional improvements. According to recent studies, gels can be used as ingredients for the total or partial replacement of saturated and trans fats in the meat, bakery and pastry industry. The evaluation of the oxidative quality of this gelled systems is significant because the production process involves the use of heat treatments and continuous stirring where large amounts of air can be incorporated. The aim of this literature review is to provide a synthesis of studies to better understand the interaction of components and to identify future improvements that can be applied in oil gelling technology. Generally, higher temperatures used in obtaining polymeric gels, lead to more oxidation compounds, while a higher concentration of structuring agents leads to a better protection against oxidation. Due to the gel network ability to function as a barrier against oxidation factors, gelled matrices are able to provide superior protection for the bioactive compounds. The release percentage of bioactive molecules can be regulated by formulating the gel matrix (type and concentration of structuring agents and type of oil). In terms of food products, future research may include the use of antioxidants to improve the oxidative stability of the reformulated products.

Structuring of Cold Pressed Oils: Evaluation of the Physicochemical Characteristics and Microstructure of White Beeswax Oleogels

The aim of the study was to characterize the gelling effect of beeswax (BW) using different types of cold pressed oil. The organogels were produced by hot mixing sunflower oil, olive oil, walnut oil, grape seed oil and hemp seed oil with 3%, 7% and 11% beeswax. Characterization of the oleogels was done using Fourier transform infrared spectroscopy (FTIR), the chemical and physical properties of the oleogels were determined, the oil binding capacity was estimated and the SEM morphology was studied. The color differences were highlighted by the CIE Lab color scale for evaluating the psychometric index of brightness (L*), components a and b. Beeswax showed excellent gelling capacity at 3% (w/w) of 99.73% for grape seed oil and a minimum capacity of 64.34%for hemp seed oil. The value of the peroxide index is strongly correlated with the oleogelator concentration. Scanning electron microscopy described the morphology of the oleogels in the form of overlapping structures of platelets similar in structure, but dependent on the percentage of oleogelator added. The use in the food industry of oleogels from cold-pressed vegetable oils with white beeswax is conditioned by the ability to imitate the properties of conventional fats.

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

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

Printing Optimization of 3D Structure with Lard-like Texture Using a Beeswax-Based Oleogels

In this study, we investigated the optimal conditions for 3D structure printing of alternative fats that have the textural properties of lard using beeswax (BW)-based oleogel by a statistical analysis. Products printed with over 15% BW oleogel at 50% and 75% infill level (IL) showed high printing accuracy with the lowest dimensional printing deviation for the designed model. The hardness, cohesion, and adhesion of printed samples were influenced by BW concentration and infill level. For multi-response optimization, fixed target values (hardness, adhesiveness, and cohesiveness) were applied with lard printed at 75% IL. The preparation parameters obtained as a result of multiple reaction prediction were 58.9% IL and 16.0% BW, and printing with this oleogel achieved fixed target values similar to those of lard. In conclusion, our study shows that 3D printing based on the BW oleogel system produces complex internal structures that allow adjustment of the textural properties of the printed samples, and BW oleogels could potentially serve as an excellent replacement for fat.

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.

Ultrasonic Treatment of Food Colloidal Systems Containing Oleogels: A Review

The use of oleogels as an alternative to solid fats to reduce the content of saturated and trans-isomeric fatty acids is a developing area of research. Studies devoted to the search for methods of obtaining oleogels with given properties are of current interest. Ultrasonic treatment as a method for modifying oleogel properties has been used to solve this problem. The number of publications on the study of the effect of ultrasonic treatment on oleogel properties is increasing. This review aimed to systematize and summarize existing data. It allowed us to identify the incompleteness of this data, assess the effect of ultrasonic treatment on oleogel properties, which depends on various factors, and identify the vector of this direction in the food industry. A more detailed description of the parameters of ultrasonic treatment is needed to compare the results between various publications. Ultrasonic treatment generally leads to a decrease in crystal size and an increase in oil-binding capacity, rheological properties, and hardness. The chemical composition of oleogels and the concentration of gelators, the amplitude and duration of sonication, the cooling rate, and the crystallization process stage at which the treatment occurs are shown to be the factors influencing the efficiency of the ultrasonic treatment.

Variations in Microstructural and Physicochemical Properties of Soy Wax/Soybean Oil-Derived Oleogels Using Soy Lecithin

Emerging natural-based polymers and materials progress and new technology innovations open the way for unique food products with high nutritional value development. In this regard, oleogel may be essential in replacing fatty acids from food products. In this study, we researched the effects of varied soy lecithin (SYL) concentrations on the various physicochemical characteristics of soy wax (SW)/refined soybean oil (RSO) oleogels. These oleogels had a soft texture. The microscopic analysis of the oleogels suggested that the thickness, length, and density of the wax crystals (needle-shaped) varied as the SYL content was changed. Colorimetric analysis indicated that the oleogels were slightly yellowish. FTIR spectrometry helped analyze the functional groups of the raw materials and the oleogels. All the functional groups present in the raw materials could be accounted for within the oleogels. The only exception is the hydrogen-bonding peak in SW, which was not seen in the FTIR spectrum of the oleogels. It was found that at a critical SYL content, the oleogel showed a stable and repeatable wax network structure. This can be described by the presence of the uniformly distributed fat crystal network in the sample. The DSC analysis revealed that the oleogel samples were thermo-reversible, with their melting and crystallization temperatures ~43 °C and ~22 °C, respectively. In gist, it can be concluded that the incorporation of SYL can impact the color, wax crystal network characteristics, thermal characteristics, and mechanical characteristics of the oleogels in a composition-dependent manner.

Analysis of Stability, Rheological and Structural Properties of Oleogels Obtained from Peanut Oil Structured with Yellow Beeswax

The aim of this study was to evaluate the macro- and microscopic properties of oleogels with yellow beeswax using different methods, especially modern optical techniques. Microrheological properties, physical stability and morphology of oleogel crystals obtained by structuring of peanut oil with yellow beeswax was analyzed. It was observed that oleogels, even with the smallest concentration of beeswax (2%), were resistant to centrifugal force. Increase in yellow beeswax concentration (from 2, 4, 6 to 8 %) resulted in significant differences in the characteristics of oleogels: increased elasticity (EI), macroscopic viscosity (MVI) and the firmness values of oleogels. It was concluded that non-invasive optical techniques (multi-speckle diffusing wave spectroscopy—Rheolaser Master) are useful in obtaining a quick evaluation of physical properties of oleogels at the microstructural level, and the received information allows for quality assessment.

Heat- and shear-reversible networks in food: A review

While nature behaves like an irreversible network with respect to entropy and time, certain systems in nature exist that are, to some extent, reversible. The property of reversibility imparts unique benefits to systems that possess them, making them suitable for designing self-healing, stimuli-responsive, and smart materials that can be used in widely divergent fields. Reversible networks are currently being exploited for applications in tissue engineering, drug delivery, and soft robotics. They are also being utilized as low-calorie fat mimetics with melt-in-your-mouth textures, as well as being explored as potential scaffolds for three-dimensional (3D) printable food, among other applications. This review aims to gather representative examples of heat- and shear-reversible networks in the food science literature from the last 30 or so years, in other words, reversible food gels made either from linear biopolymers or from colloidal, particulate dispersions, including those that have been modified specifically to induce reversibility. An overview of the network mechanisms involved that impart reversibility, including a discussion of the strength and range of forces involved, will be highlighted. A model that explains why certain networks are thermoreversible while others are shear-reversible, and why others are both, will also be proposed. A fundamental understanding of these mechanisms will prove invaluable when designing reversible networks in the future, making possible the precise control of their properties, thus fostering innovative applications within the food industry and beyond.

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.

Evaluation of Structural Behavior in the Process Dynamics of Oleogel-Based Tender Dough Products

The current trend is represented by replacing solid fats with structured liquid oil while maintaining the plastic properties of food products. In this study, the behavior of refined sunflower oil structured with various agents (carnauba wax-CRW, β-sitosterol:beeswax-BS:BW, β-sitosterol:lecithin-BS:LEC, and glycerol monostearate-GM) was evaluated in the process dynamics of oleogel-based tender dough products. The oleogel with the mixture of β-sitosterol:beeswax (OG_BS:BW) displayed the highest capacity to retain oil inside the matrix with a percentage of oil loss as low as 0.05% and also had a significantly higher hardness (6.37 N) than the reference, a commercial margarine (MR—3.58 N). During cooling from 90 to 4 °C, the increase in oleogel’ viscosity results from oleogelator’s liquid–solid phase transition. As demonstrated by the frequency sweeps performed, storage modulus G′ was higher than loss modulus G″, no cross-over points were observed, and the strongest gel network was for the oleogel with glycerol monostearate (OG_GM). Regarding the dough, the sample prepared using the oleogel with carnauba wax (D_CRW) showed the strongest hardness (92.49 N) compared to the reference (D_MR—21.80 N). All the oleogel-containing doughs had elastic solid-like behavior. The samples with margarine (D_MR) and the mixture of β-sitosterol:lecithin (D_BS:LEC) presented the lowest value of both moduli of G’ and G” during the frequency sweep. The biscuits formulated with commercial margarine (B_MR) registered a hardness of 28.74 N. Samples with oleogels showed a specific tenderness for tender dough products, thus being suitable for this type of product (11.22–20.97 N).

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

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

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

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

Oleogels prepared with low molecular weight gelators: Texture, rheology and sensory properties, a review

There is a growing need for healthier foods with no trans and reduced saturated fat. However, solid fats play critical roles in texture and sensory attributes of food products, making it challenging to eliminate them in foods. Recently, the concept of oleogelation as a novel oil structuring technique has received numerous attentions owing to their great potential to mimic the properties of solid fats. Understanding textural, rheological and sensory properties of oleogels helps predict the techno-functionalities of oleogels to replace solid fats in food products. This research critically reviews the textural and rheological properties of oleogels prepared by low molecular weight oleogelators (LMWGs) and functional characteristics of foods formulated by these oleogels. The mechanical properties of LMWG-containing oleogels are comprehensively discussed against conventional solid fats. The interactions between the oleogel and its surrounding food matrix are explained, and the sensory attributes of oleogel containing reformulated products are highlighted. Scientific insights into the texture and rheological properties of oleogels manufactured with a wide range of low molecular gelators and their related products are provided in order to boost their implication for creating healthier foods with high consumer acceptability. Future research opportunities on low molecular weight gelators are also discussed.

A Study of the Quantitative Relationship between Yield Strength and Crystal Size Distribution of Beeswax Oleogels

Beeswax and beeswax hydrocarbon-based oleogels were studied to evaluate the quantitative relationship between their yield strength and crystal size distribution. With this aim, oleogels were prepared using four different cooling regimes to obtain different crystal size distributions. The microstructure was evaluated by polarized light microscopy. The yield strength is measured by the cone penetration test. Oleogels were characterized by average grain size, microstructure entropy, grain boundary energy per unit volume, and microstructure temperature. We have provided the theoretical basis for interpreting the microstructure and evaluating the microstructure-based hardening of oleogels. It is shown that the microstructure entropy might be used to predict the yield strength of oleogels by the Hall-Petch relationship.

Lactoferrin particles assembled via transglutaminase-induced crosslinking: Utilization in oleogel-based Pickering emulsions with improved curcumin bioaccessibility

In this study, the optimal environmental condition for preparation of lactoferrin particles assembled via transglutaminase-induced crosslinking (TG-LF particles) was pH 8, 100 U/g of TG concentration, 50 °C and 2 h of crosslinking time. Contact angle of TG-LF particles was 79°. Then, corn oil-based oleogels were prepared with carnauba wax (CW), behenyl alcohol (BA) and CW-BA mixture at 1:4 ratio (MT). To investigate the effect of oleogels on oleogel-based Pickering emulsions, oleogel-based Pickering emulsions were prepared by a two-step method using different oleogels as the oil phase and the TG-LF particles as the emulsifier. In vitro digestion study revealed that CW oleogel-based Pickering emulsion had the highest lipolysis rate and curcumin bioaccessibility. This study demonstrated that TG-LF particle-stabilized oleogel-based Pickering emulsions had good performance in curcumin delivery, which provided a new idea for the preparation of Pickering emulsifier and enriched the knowledge in the field of oleogel-based Pickering emulsion.

Trans fatty acids in food: A review on dietary intake, health impact, regulations and alternatives

Trans fats are desired by the edible oil industry as they impart firmness, plasticity, and oxidative stability to oil. However, clinical trials have demonstrated the adverse effects of trans fats in food on human health and nutrition. Regulatory actions have been taken up by government and non-government bodies worldwide to eliminate the presence of trans fats in the food supply. The World Health Organization (WHO) has launched a "REPLACE" action plan to eliminate trans-fat from the global food industry by 2023. A few enabling technologies are developed to mitigate trans fats namely, trait-enhanced oils, modification in the hydrogenation process, interesterification, fractionation, blending, and oleogelation. Some of them have the drawback of replacing trans-fat with saturated fats. Interesterification and oleogelation are in-trend techniques with excellent potential in replacing trans fats without compromising the desired functionality and nutritional quality attributes. This review presents an overview of trans fatty acid for example, its dietary intake in food products, possible adverse health impact, regulations, and approaches to reduce the usage of trans fats for food application. PRACTICAL APPLICATION: The requirement for the replacement of trans fatty acids (TFAs) in food supply globally has challenged the food industry to find a novel substitute for trans fats without compromising the desired functionality and nutritional property. This review presents detailed background on trans fats, their health impacts and current trends of reformulation of oils and fats to mitigate their presence in food supply chains. Information compiled in this paper will help food scientists and technologists, chemists, food processors, and retailers as there is an urgent need to find novel technologies and substitutes to replace trans fats in processed foods.

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

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

Margarines: Historical approach, technological aspects, nutritional profile, and global trends

Margarines are an expanding market worldwide due to large-scale commercial, lower cost, growth of bakery and confectionery markets, and seasonal independence. The fatty acid composition, solid fat content, consistency, and melting point of the fats used in margarine determine their functional properties. Due to its proven association with increased risk of cardiovascular diseases, the recommendations of the World Health Organization and the enactment of laws in several countries to eliminate industrially produced trans fatty acids (TFA) have resulted in the prohibition or progressive reduction in the use of partially hydrogenated fat. However, issues related to high levels of TFA and saturated fatty acids still constitute a challenge in the formulation of this product category. Current trends on margarine production addition of phytosterols, non-lipid components, organogels, and new interesterified fat bases are reviewed. This review aims to present a historical view and the technological evolution of margarines, including their production processes, formulations, and physical and nutritional characteristics, as well as legislation, and main trends.