Oleogelation: From Scientific Feasibility to Applicability in Food Products

Formation, characterization, and application of natural bioactive phytosterol-based oleogels: A review

Oleogels are innovative structured fat systems that can replace detrimental lipids and saturated fats. Among the various gelators used to construct oleogels, phytosterols are regarded as potential oleogelators due to ability to lower blood cholesterol levels and protect patients from cardiovascular illnesses, although little research has been conducted on phytosterols. This article examines the formation, characterization, and application of phytosterol-based oleogels in detail. The oleogelation behaviors of phytosterol-based oleogels are affected by their formulation, which includes phytosterol type, combined oleogelator, proportion, concentration and oil type. These oleogels exhibit potential applications as solid fat substitutes without affecting the texture or sensory properties of food products or as effective delivery vehicles. To encourage the research and implementation of phytosterol-based oleogels, we will ultimately not only highlight problems related to their use in food processing, but also provide a few viewpoints, with the goal of providing fresh insights for advancing trends.

Preparation, characterization, and coating effect of bio-active nano-emulsion based on combined plant essential oils on quality of grass carp fillets

This study aimed to develop a satisfactory essential oil (EO) nano-emulsion through high pressure microjet technology and explore its physiochemical properties and synergistic coating effects on grass carp fillets. The optimal conditions for oregano/litsea cubeba (6:4, wt%/wt%) nano-emulsion were shown to be 80 s high pressure microjet pretreatment time, 9000 lb per square inch pretreatment pressure, 6 % oil phase, and 3:2 Km (mass ratio of surfactant to co-surfactant). The obtained nano-emulsion exhibited 100.42 ± 0.96 nm oil diameter at 4 °C after 15-day storage, coupled with high stability after centrifugation, freeze-thaw and heating treatment. Compared with untreated samples at day 6 storage, the nano-emulsion-treated grass carp fillets exhibited improved textural properties, higher water-holding capacity (74.23 % ± 0.80 %), lower total volatile basic nitrogen (TVB-N, 13.46 ± 0.30 mg/100g)/thiobaric acid (TBA,0.43 ± 0.02 mgMDA/100g), and lower total viable spoilage bacteria count (4.98 ± 0.21 lgCFU/g). This study facilitates understanding the combined EOs nano-emulsion on improving the shelf life of grass carp fillets.

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.

Chocolate Ganaches: Formulation, Processing and Stability in View of the New Production Trends

This review aims at the current trends in chocolate ganache production and recipe formulation. Ganache is a blend of chocolate, sugars, dairy, and other ingredients commonly used to fill pralines, pastries, etc. In spite of ganache's popularity in the food industry, a comprehensive review focused on the application of functional substances and ganache processing has not been discussed in the scientific literature. This review addresses the new ways of applying special ingredients, such as vegetable fats and seeds, flavor infusions, oleogels, hemp products, etc., which can be added to the ganache matrix to achieve desirable properties. In particular, the application of sterols and sterol esters as functional substances of oleogels seems to be a very promising method, enhancing the ganache fat profile. The elevated caloric content that is characteristic of ganache can be substantially attenuated through the application of hydrocolloids and/or fruit-based components, thereby offering the potential for caloric reduction without compromising on taste. The various alterations to ganache formulations by the application of natural substances offer a large base for the development of novel ganache variants and relevant food products.

Characterization of acorn oil and its application on carnauba wax-based oleogel and chocolate spread

This study aimed to characterize acorn oil (AO) and carnauba wax-based acorn oil oleogel (AOG) and the effect of AOG replacement on the textural and sensorial properties of chocolate spread. Oil yields from cold-pressing (Quercus longipes) were around 14%wt with a nice nutty smell. The main fatty acids of AO were included oleic, linoleic, and palmitic acid (44, 38, and 10%wt) respectively. The prepared AOG using 6%wt of carnauba wax (CW) showed high strength (G' > 100 mPa) and oil binding capacity ∼87 %. Based on microstructure assays platelet-like and β' polymorphic triglyceride crystalline networks were formed in AOG. The Pickering AOG/water emulsions in the volumetric ratio of from 90:10 up to 40:60 were stable due to the placement of CW-based AOG particles at the interface of water/oil as Pickering stabilizer. The high physical stability of the emulgel against phase separation is considered an important advantage for using oleogel in chocolate spread formulations instead of vegetable oils, which usually have a high percentage of oil release. The spreads prepared by replacing 50%wt AOG with butter showed acceptable textural and sensorial properties.

New Insight into Food-Grade Emulsions: Candelilla Wax-Based Oleogels as an Internal Phase of Novel Vegan Creams

Cream-type emulsions containing candelilla wax-based oleogels (EC) were analyzed for their physicochemical properties compared to palm oil-based creams (EP). The microstructure, rheological behavior, stability, and color of the creams were determined by means of non-invasive and invasive techniques. All the formulations exhibited similar color parameters in CIEL*a*b* space, unimodal-like size distribution of lipid particles, and shear-thinning properties. Oleogel-based formulations were characterized by higher viscosity (consistency index: 172-305 mPa·s, macroscopic viscosity index: 2.19-3.08 × 10-5 nm-2) and elasticity (elasticity index: 1.09-1.45 × 10-3 nm-2), as well as greater resistance to centrifugal force compared to EP. Creams with 3, 4, or 5% wax (EC3-5) showed the lowest polydispersity indexes (PDI: 0.80-0.85) 24 h after production and the lowest instability indexes after environmental temperature changes (heating at 90 °C, or freeze-thaw cycle). EC5 had particularly high microstructural stability. In turn, candelilla wax content ≥ 6% w/w accelerated the destabilization processes of the cream-type emulsions due to disintegration of the interfacial layer by larger lipid crystals. It was found that candelilla wax-based lipids had great potential for use as palm oil substitutes in the development of novel vegan cream analogues.

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.

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.

Bigels as Delivery Systems: Potential Uses and Applicability in Food

Bigels have been mainly applied in the pharmaceutical sector for the controlled release of drugs or therapeutics. However, these systems, with their intricate structures, hold great promise for wider application in food products. Besides their classical role as carrier and target delivery vehicles for molecules of interest, bigels may also be valuable tools for building complex food structures. In the context of reducing or even eliminating undesirable (but often highly functional) food components, current strategies often critically affect food structure and palatability. The production of solid fat systems that are trans-fat-free and have high levels of unsaturated fatty acids is one of the challenges the food industry currently faces. According to recent studies, bigels can be successfully used as ingredients for total or partial solid fat replacement in complex food matrices. This review aims to critically assess current research on bigels in food and pharmaceutical applications, discuss the role of bigel composition and production parameters on the characteristics of bigels and further expand the use of bigels as solid fat replacers and functional food ingredients. The hydrogel:oleogel ratio, selected gelators, inclusion of surfactants and encapsulation of molecules of interest, and process parameters (e.g., temperature, shear rate) during bigel production play a crucial role in the bigel's rheological and textural properties, microstructure, release characteristics, biocompatibility, and stability. Besides exploring the role of these parameters in bigel production, future research directions for bigels in a food context are explored.

Food-Grade Oleogels: Trends in Analysis, Characterization, and Applicability

Currently, a large number of scientific articles can be found in the research literature in the field focusing on the use of oleogels for food formulation to improve their nutritional properties. The present review focuses on the most representative food-grade oleogels, highlighting current trends in terms of the most suitable methods of analysis and characterization, as well as trends in their application as substitutes for saturated and trans fats in foods. For this purpose, the physicochemical properties, structure, and composition of some oleogelators are primarily discussed, along with the adequacy of oleogel incorporation for use in edible products. Analysis and characterization of oleogels by different methods are important in the formulation of innovative foods, and therefore, this review discusses the most recent published results regarding their microstructure, rheological and textural properties, and oxidative stability. Last but not least, issues related to the sensory properties of oleogel-based foods are discussed, highlighting also the consumer acceptability of some of them.

Beyond Sol-Gel: Molecular Gels with Different Transitions

The existence of sol–gel transitions is one of the most manifest properties of molecular gels. These transitions reflect their nature since they correspond to the association or dissociation of low weight molecules through non-covalent interactions to form the network constitutive of the gel. Most described molecular gels undergo only one gel-to-sol transition upon heating, and the reverse sol-to-gel transition upon cooling. It has been long observed that different conditions of formation could lead to gels with different morphologies, and that gels can undergo a transition from gel to crystals. However, more recent publications report molecular gels which exhibit additional transitions, for instance gel-to-gel transitions. This review surveys the molecular gels for which, in addition to sol–gel transitions, transitions of different nature have been reported: gel-to-gel transitions, gel-to-crystal transition, liquid–liquid phase separations, eutectic transformations, and synereses.

Physicochemical Properties and Cookie-Making Performance as Fat Replacer of Wax-Based Rice Bran Oil Oleogels

Reducing the intake of trans and saturated fatty acids is a trend in healthy eating. In this study, the oleogels were prepared from rice bran oil (RBO), candle wax (CDW), beeswax (BW), rice bran wax (RBW), and carnauba wax (CRW), respectively, and the results based on their physicochemical properties and crystal structures at critical concentrations, 6 wt.%, 8 wt.%, and 10 wt.%, were determined to further investigate the oleogels as a shortening substitute in cookie recipes. Oleogel has a smooth, spreadable β' crystal shape which creates excellent sensory properties and improves the texture, but also has some economic benefits. A comparison between the oleogels formed at critical concentrations and those with improved mass fractions was performed in several analyses such as PLM and texture, and the oleogels with higher mass fractions had a greater hardness and stickiness and denser crystal structures. This study was used to optimize the cookie recipe by partially replacing shortening with oleogel and preparing the cookies according to the 0:1, 3:7, 1:1, 7:3, 1:0 oleogel shortening mixture, respectively. Based on the results of the textural analysis, a colorimetric and sensory evaluation of the optimized formulation of oleogels in cookies, it was evident that BW and RBW oleogels have more potential to replace shortening in cookies than CDW and CRW oleogels. In particular, oleogels with a concentration of 6 wt.% RBW (RBW-6) and at a 7:3 (oleogel:shortening) shortening replacement exhibited a hardness and crispness of 15.75 N and 97.73 g, respectively, with an L* value of 66.66 and a sensory score of 22.32 ± 0.09. The value for the color perception difference (dE) between the cookies and the control group was -3.73, which allowed us to obtain a good product with a quality and characteristics similar to shortening. This supports the feasibility of new solid fats to replace traditional plastic fats in baked goods.

Walnut Oil Oleogels as Milk Fat Replacing System for Commercially Available Chocolate Butter

A breakfast spread named chocolate butter exists on the market. For economic and technological reasons, cream in the original recipe is replaced with vegetable oils such as palm oil or by partially hydrogenated sunflower oil. The study aims to reformulate chocolate flavor butter, using cold pressed walnut oil (WO) oleogels (OGs) structured with 10% waxes and monoglyceride (MG), as a milk fat replacing system. The rheological, textural and microscopic characteristics of the oleogels and the spreads were compared. Oil binding capacity (OBC) and colorimetry were also assessed. Fourier transform infrared studies were used to monitor the composition of the samples. Oleogels and oleogel based chocolate butter behaved like strong gels (G’ > G”). The use of candelilla wax (CW) led to the formation of a much firmer spread (S-CW), with a hardness of 3521 g and G’LVR of 139,920 Pa, while the monoglyceride-based spread (S-MG) registered a hardness of 1136 g and G’LVR 89,952 Pa. In the spreadability test, S-CW registered a hardness of 3376 g and hardness work of 113 mJ, comparable to the commercially available chocolate butter. The formulated spreads exhibited shear thinning effects, and increased viscosity with decreasing temperature. A large round peak at 3340 cm−1 was present in the spectra of the candelilla wax-based oleogel (OG-CW) and the reference spreads due to hydrogen bonding, but was absent in S-CW or S-MG. The FTIR spectra of the alternative spreads exhibited the same peaks as the WO and the oleogels, but with differences in the intensities. S-CW exhibited a dense crystal network, with spherulitic crystals of 0.66−1.73 µm, which were statistically similar to those of the reference made from cream (S-cream). S-MG exhibited the lowest stability upon centrifugation, with an OBC of 99.76%. Overall, both oleogel-based chocolate spreads can mimic the properties of the commercially existing chocolate butter references.

Building blocks of β-sitosterol-γ-oryzanol gels revealed by small-angle neutron scattering and real space modelling

Mixtures of β-sitosterol and γ-oryzanol form gels in a range of organic solvents. Despite being widely studied, particularly as potential oleogels for food application, details of the intrinsic gel-forming building blocks remain unclear. Small-angle neutron scattering (SANS) combined with solvent contrast variation has been used to evaluate potential structural models. While evidence exists that the building blocks are hollow cylinders (tubules), the simultaneous fitting of twelve contrast-varied SANS data sets indicates that the previously proposed model of double walled tubules is incorrect. Predicted scattering based on real space models provides compelling evidence that the origin of the gelling behaviour is the limited assembly of adjacent tubules to form a space-filling network of fibrils.

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.

Effect of Cooling Rate on the Oleogel Properties of Wax–Wax-Hydrolyzate Mixtures

In this contribution, the effect of cooling rates on a wide compositional range of waxes as oleogel structurants was systematically investigated. The different waxes exhibited varying levels of wax esters (WE), fatty acids (FA), fatty alcohols (FaOH) and hydrocarbons (HC) and were systematically altered by combinations of sunflower wax (SFW), bees wax (BW) and their hydrolyzed variants (SFWh, BWh). By applying slow, medium and high cooling rates, the resulting gel properties were investigated in terms of firmness, calorimetry and microstructure. It was found that the calorimetrical signal is mainly affected by the waxes’ composition. However, due to enlarged dynamic induction times upon crystallization, a shift in dissolution temperature could be observed in heating scans. In our latest work we were able to formulate the degree of homogeneity (DoH), with which it was possible to predict the undercooling in SFW mixtures. The introduction of a novel method emerged for firmness measurements of oleogels treated with the different rates. Thus, it was possible to detect with high sensitivity for all waxes for applied cooling rates, caused by modification of microstructure. Combination of different methods further elucidated that higher rates need to be applied to further scale firmness of oleogels in industrial processes.

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

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

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.

Sonication-Induced, Solvent-Selective Gelation of a 1,8-Napthalimide-Conjugated Amide: Structural Insights and Pollutant Removal Applications

Reported herein is the synthesis, characterization, and dye removal applications of a highly solvent-selective organogel-forming amide, compound 1, which contains a 1,8-naphthalmide moiety, flexible n-hexyl chain, and benzene ring. This compound displayed remarkable solvent selectivity, with gel formation occurring only in the presence of alkylated aromatic solvents. Detailed structural characterization of the gels, combined with notable theoretical insights, is invoked to explain the highly selective gelation properties of compound 1, as is a comparison to non-gel forming structural isomer 2, which contains the same structural elements in a different arrangement. Finally, the ability of the gel derived from compound 1 to act as a reusable material for the efficient removal of cationic organic dyes from contaminated aqueous environments is also reported, with up to 11 repeated uses of the gel still maintaining the ability to effectively remove Rhodamine B.

Effect of Biodegradable Hydrophilic and Hydrophobic Emulsifiers on the Oleogels Containing Sunflower Wax and Sunflower Oil

The use of an appropriate oleogelator in the structuring of vegetable oil is a crucial point of consideration. Sunflower wax (SFW) is used as an oleogelator and displays an excellent potential to bind vegetable oils. The current study aimed to look for the effects of hydrophobic (SPAN-80) and hydrophilic (TWEEN-80) emulsifiers on the oleogels prepared using SFW and sunflower oil (SO). The biodegradability and all formulations showed globular crystals on their surface that varied in size and number. Wax ester, being the most abundant component of SFW, was found to produce fibrous and needle-like entanglements capable of binding more than 99% of SO. The formulations containing 3 mg of liquid emulsifiers in 20 g of oleogels showed better mechanical properties such as spreadability and lower firmness than the other tested concentrations. Although the FTIR spectra of all the formulations were similar, which indicated not much variation in the molecular interactions, XRD diffractograms confirmed the presence of β' form of fat crystals. Further, the mentioned formulations also showed larger average crystallite sizes, which was supported by slow gelation kinetics. A characteristic melting point (Tm~60 °C) of triglyceride was visualized through DSC thermograms. However, a higher melting point in the case of few formulations suggests the possibility of even a stable β polymorph. The formed oleogels indicated the significant contribution of diffusion for curcumin release. Altogether, the use of SFW and SO oleogels with modified properties using biodegradable emulsifiers can be beneficial in replacing saturated fats and fat-derived products.

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

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

Application of Analytical Methods for the Comprehensive Analysis of Oleogels-A Review

Numerous empirical studies have already been conducted on the innovative fat-replacing system defined as oleogel, creating a real urge for setting up a framework for future research, rather than conducting studies with arbitrary methods. This study re-evaluates the utility of some analyses and states some conclusions in order to eliminate the reluctance of food processors and consumers towards the utilization of oleogels as ingredients. The review presents extensively the methods applied for the characterization of various oleogels, while highlighting their addressability or inconveniences. The discussed methods were documented from the research published in the last five years. A classification of the methods is proposed based on their aims or the utility of the results, which either describe the nano-structure and the network formation, the quality of the resulting oleogel or its suitability as food ingredient or other edible purposes. The general conclusions drawn for some classes of oleogels were also revisited, in order to ease the understanding of the oleogel behaviour, to encourage innovative research approaches and to stimulate the progress in the state of art of knowledge.

Oleogels-Their Applicability and Methods of Characterization

Oleogels or, more precisely, non-triglyceride structured lipid phases have been researched excessively in the last decade. Yet, no comprehensive knowledge base has emerged, allowing technology elevation from the laboratory bench into the industrial food application. That is partly due to insufficient characterization of the structuring systems studied. Examining a single composition decided upon by arbitrary methods does not stimulate progress in the research and technology area. A framework that gives much better guidance to product applications can easily be derived. For example, the incremental structure contribution concept is advocated as a parameter to compare the potency of structuring systems. These can straightforwardly be determined by combining solubility data and structural measurements in the recommended manner. The current method to determine the oil-binding capacity suffers from reproducibility and relevance. A newly developed method is suggested to overcome these shortcomings. The recommended new characterization of oleogels should contribute to a more comprehensive knowledge base necessary for product innovations.