Evaluation of oil-gelling properties and crystallization behavior of sorghum wax in fish oil

Fabrication and characterization of oleic acid/sesame protein isolate/ poly (vinyl) alcohol core-shell nanofibers: Mitigating lipid oxidation by emulsion electrospinning

Formulated oil-in-water (O/W) emulsions of oleic acid (OA) using sesame protein isolate (SPI) were processed via emulsion electrospinning with poly (vinyl) alcohol (PVA) to fabricate core-shell nanofibers for lipid oxidation prevention. The emulsion droplet size and viscosity increased as the oil volume fraction rose from 5 % to 30 %. The morphology tests and Fourier transform infrared spectroscopy (FTIR) confirmed the uniformity of nanofibers and OA encapsulation with hydrogen bonding. The thermal stability, mechanical properties, and water contact angle (WCA) of the nanofiber films improved with increased OA content. Encapsulation efficiency was 94.76 % and storage stability was maintained for 7 days in 5 % oil fraction nanofibers. The nanofibers showed lower oxidation and superior oxidative resistance to free OA, with the lowest peroxide value (POV, 2.14 mmol/L) and thiobarbituric acid-reactive substances (TBARS, 36.75 μmol/L). In conclusion, the OA/SPI/PVA (PE) core-shell nanofibers via emulsion electrospinning are efficient for fatty acid encapsulation in functional foods.

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

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

Synthesis of lipophilic vitamin C and evaluation of its antioxidant performance in sunflower seed oil frying

The present study involved the synthesis and analysis of a lipophilic form of vitamin C, namely tetrabutyryl vitamin C ester (TVCE). TVCE is synthesized by a simple one-step method, combining the advantages of VC and butyric acid. Its antioxidant efficacy on sunflower seed oil frying was evaluated by assessing lipid oxidation parameters including peroxide number (POV), carbonyl number (CV), and paraniline number (pAV). Furthermore, changes in the fatty acid composition of the oil were monitored using techniques such as infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and gas chromatography (GC). The findings demonstrated that lipophilic vitamin C exhibited superior protection against oxidation during frying compared to vitamin E, suggesting that it may be an effective fat-soluble antioxidant. The study provides a new field for the utilization of vitamin C and a new idea for the development of efficient antioxidants.

Development and characterization of wax-bovine bone protein-grapeseed oil composite oleogels: Experimental and molecular simulation studies

Three new types of composite oleogel formulations were designed. Specifically, oleogels were prepared using 90% grapeseed oil as the oil phase and carnauba wax (CW)/beeswax/rice bran wax-bovine bone protein (BBP) as gelators. All samples were solid and had an oil-binding capacity of >90%. BBP addition considerably improved the waxy texture of the oleogel and had an important effect on the crystalline network. X-ray diffractometry indicated that BBP increased the β'-crystal content. All samples showed sol-gel thermodynamic behavior under temperature scanning. Fourier-transform infrared spectroscopy and molecular docking confirmed the formation of noncovalent interactions dominated by van der Waals forces during the development of the oleogel. The optimal components of the three oleogels exhibited an excellent effect of slowing down the release of free fatty acids. This study could serve as a reference for the development and application of wax-protein as a new binary gelator in the food industry.

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

BACKGROUND

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

RESULTS

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

CONCLUSION

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

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.

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.

A review of different frying oils and oleogels as alternative frying media for fat-uptake reduction in deep-fat fried foods

Purpose

This review aims to examine the potential of oleogels as a frying medium to decrease oil absorption during deep-frying and enhance the nutritional and energy content of foods. By investigating the factors influencing oil incorporation during deep-frying and examining the application of oleogels in this process, we seek to provide insights into using oleogels as an alternative to traditional cooking oils.

Scope

Deep-frying, a widely used cooking method, leads to the retention of large amounts of oil in fried food, which has been associated with health concerns. To address this issue, researchers have investigated various methods to minimize oil absorption during frying. One promising approach is the use of oleogels, which are thermo-reversible, three-dimensional gel networks formed by entrapment of bulk oil with a low concentration (<10% of weight) of solid lipid materials known as oleogelators. This review will focus on the following aspects: a) an overview of deep-fried foods, b) factors influencing oil uptake and underlying mechanisms for oil absorption during deep-frying, c) the characterization and application of different frying oils and their oleogels in deep-fried foods, d) components of the oleogel system for deep-frying, and e) the health impact, oxidative stability, and sensory acceptability of using oleogels in deep-frying.

Key findings

The review highlights the potential of oleogels as a promising alternative frying medium to reduce fat absorption in deep-fried foods. Considering the factors influencing oil uptake during deep-frying, as well as exploring the properties and applications of different frying oils and their oleogels, can result in improved product qualities and heightened consumer acceptance. Moreover, oleogels offer the advantage of lower fat content in fried products, addressing health concerns associated with traditional deep-frying methods. The capacity to enhance the nutritional and energy profile of foods while preserving sensory qualities and oxidative stability positions oleogels as a promising choice for upcoming food processing applications.

Synthesis of lipoic acid ferulate and evaluation of its ability to preserve fish oil from oxidation during accelerated storage

Lipoic acid ferulate (LAF) was synthesized and its anti-free radical ability in vitro was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonicacid) (ABTS) assays. Protective effects of LAF in stabilizing fish oil were tested, compared to antioxidants such as lipoic acid, ferulic acid and tert-butylhydroxyquinone (TBHQ) by measuring peroxide values, thiobarbituric acid reactants, p-anisidine values, nuclear magnetic resonance (NMR) spectra and gas chromatography-mass spectrometry (GC-MS) spectra of fish oil during accelerated storage (12 days, 80 °C). The inhibitory effect of these antioxidants on fish oil oxidation followed the order TBHQ ≧ LAF > ferulic acid > lipoic acid. In addition, the omega-3 polyunsaturated fatty acids were the first to be oxidized. The formation of oxidation products followed a first-order kinetic model, and the addition of LAF effectively reduced the reaction rate constants. Therefore, LAF can effectively slow down the formation of oxidative products and prolong the shelf life of fish oil.

Macadamia oil-based oleogels as cocoa butter alternatives: Physical properties, oxidative stability, lipolysis, and application

In this study, macadamia oil-based oleogels were prepared using monoglyceride stearate (MG) as a gelator with a low critical gelation concentration (3.0 wt%). The physical properties of the oleogels were evaluated by polarized light microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, texture and rheological analysis. And the lipid digestion and oxidative stability of the macadamia oil were determined by pH titration and accelerated oxidation test, respectively. The results showed that the hardness, oil binding capacity, and thermal stability of the oleogels increased with increasing MG concentration, which was attributed to the formation of a network of MG crystals held together by van der Waals interactions and hydrogen bonds. Rheological analysis indicated that all the oleogels exhibited a thermally reversible solid-to-liquid transition and viscoelastic behavior at ambient temperatures. Moreover, the formation of oleogels increased fatty acid release during in vitro lipid digestion and improved the oxidative stability of the macadamia oil. In addition, the potential application of these oleogels as replacements for saturated fats in foods was demonstrated by creating a chocolate product where the cocoa butter was replaced with macadamia oil-based oleogels with a high degree of unsaturation. These results can provide guidance for the preparation of macadamia oil-based oleogels, which may increase their application in foods.

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.

Emerging photoelectric devices for neuromorphic vision applications: principles, developments, and outlooks

The traditional von Neumann architecture is gradually failing to meet the urgent need for highly parallel computing, high-efficiency, and ultra-low power consumption for the current explosion of data. Brain-inspired neuromorphic computing can break the inherent limitations of traditional computers. Neuromorphic devices are the key hardware units of neuromorphic chips to implement the intelligent computing. In recent years, the development of optogenetics and photosensitive materials has provided new avenues for the research of neuromorphic devices. The emerging optoelectronic neuromorphic devices have received a lot of attentions because they have shown great potential in the field of visual bionics. In this paper, we summarize the latest visual bionic applications of optoelectronic synaptic memristors and transistors based on different photosensitive materials. The basic principle of bio-vision formation is first introduced. Then the device structures and operating mechanisms of optoelectronic memristors and transistors are discussed. Most importantly, the recent progresses of optoelectronic synaptic devices based on various photosensitive materials in the fields of visual perception are described. Finally, the problems and challenges of optoelectronic neuromorphic devices are summarized, and the future development of visual bionics is also proposed.

Antioxidative properties of fish roe peptides combined with polyphenol on the fish oil oleogel

BACKGROUND

This study aimed to investigate the effects of large yellow croaker (Larimichthys crocea) roe protein hydrolysate (LYCPH)-polyphenol (catechin (CA), gallic acid (GA), and tannic acid (TA)) conjugates on the oxidative stability of fish oil in an oleogel system.

RESULTS

Scanning electron microscopy and Fourier transform infrared spectroscopy suggested that the LYCPH-polyphenol conjugates were nearly spherical and non-covalent and that covalent effects could coexist between LYCPH and polyphenols. LYCPH-TA exhibited the highest ABTS scavenging, reducing capacities, and emulsifying stability. Raman spectra and chemometrics revealed that LYCPH-TA loaded with oleogels had the best oxidative stability. Additionally, 32 volatile compounds were identified in fish oil by headspace gas chromatography-ion mobility spectrometry.

CONCLUSION

Overall, this study demonstrated that fish oil oleogels loaded with LYCPH-polyphenol conjugates could inhibit fish oil oxidation. © 2022 Society of Chemical Industry.

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.

Determination of characteristic evaluation indexes for novel cookies prepared with wax oleogels

BACKGROUND

Wax-based oleogels showed better performance as a substitute for shortening in cookies, but the relationship between the structure and physical properties of wax oleogels and cookies quality has not been elucidated, which limit its further application. In this regard, the effect of structure and physical properties of wax oleogels on the quality of cookies was investigated, and the characteristic indexes for evaluating the quality of novel cookies prepared with wax oleogels were determined.

RESULTS

The results showed that oleogels with 5-9% proportion of rice bran wax (RBX) and candelilla wax (CDW) produced soft cookies with porous structure, desired spread and color. Compared with shortening, wax oleogels with lower solid fat content (SFC, 4.5-11%, 25 °C) and higher β' crystals (2795.7-11 671.3) produced cookies with similar hardness to that of shortening. Besides, the hardness of wax oleogel-based cookies depends more on the amount of crystals than crystal size. In the results, SFC, β' crystals, viscosity and elastic modulus (G') were determined to be the characteristic evaluation indexes for the quality of cookies prepared with wax oleogels. Cookies with wax oleogels with higher SFC, β' crystal, viscosity and G' are softer.

CONCLUSION

The quality of novel cookies prepared with wax oleogels can be controlled by the SFC and β' crystal of wax oleogels. © 2022 Society of Chemical Industry.

Encapsulated Microstructures of Beneficial Functional Lipids and Their Applications in Foods and Biomedicines

Beneficial functional lipids are essential nutrients for the growth and development of humans and animals, which nevertheless possess poor chemical stability because of heat/light-sensitivity. Various encapsulation technologies have been developed to protect these nutrients against adverse factors. Different microstructures are exhibited through different encapsulation methods, which influence the encapsulation efficiency and release behavior at the same time. This review summarizes the effects of preparation methods and process parameters on the microstructures of capsules at first. The mechanisms of the different microstructures on encapsulation efficiency and controlled release behavior of core materials are analyzed. Next, a comprehensive overview on the beneficial functional lipids capsules in the latest food and biomedicine applications are provided as well as the matching relationship between the microstructures of the capsules and applications are discussed. Finally, the remaining challenges and future possible directions that have potential interest are outlined. The purpose of this review is to convey the construction of beneficial functional lipids capsules and the function mechanism, a critical analysis on its current status and challenges, and opinions on its future development. This review is believed to promote communication among the food, pharmacy, agronomy, engineering, and nutrition industries.

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.

Effects of Grafting Degree on the Physicochemical Properties of Egg White Protein-Sodium Carboxymethylcellulose Conjugates and Their Aerogels

To improve the mechanical strength and oil-loading performances of egg white protein (EWP) aerogel, the effects of different grafting degrees on the modification of EWP by sodium carboxymethylcellulose (CMC-Na) were investigated. After different dry-heat treatment durations (0, 12, 24, 36, and 48 h), the EWP/CMC-Na conjugates with different grafting degrees (noted as EC0, EC12, EC24, EC36, and EC48, respectively) were obtained. Subsequently, the physicochemical properties of the conjugates, as well as the microstructure, mechanical properties, pore parameters, emulsification properties and oil-carrying properties of the conjugated aerogels, were characterized. The results showed that EC12 (with a grafting degree of 8.35%) aerogel possessed a uniform structure, the largest specific surface area, and the best emulsification performance. This facilitated a more robust aerogel (2.05 MPa) with nearly three times the mechanical strength of EWP aerogel. Moreover, this had a positive influence on the efficient loading and stable retention of oil. EC12 aerogel thus achieved an oil absorption capacity of 5.46 g/g aerogel and an oil holding capacity of 31.95%, and both values were nearly 1.7 times higher than those of EWP aerogel. In general, the EWP-based aerogel with a grafting degree of 8.35% had the best mechanical and oil-loading properties.

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.

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.

Effect of oleogelation on physical properties and oxidative stability of camellia oil-based oleogels and oleogel emulsions

In this work, the camellia oil-based oleogels and O/W oleogel emulsions were prepared with glycerol monolaurate (GML) as an oleogelator, which had a critical gelation concentration of 3 wt%. Results showed that with the increasing GML concentration, a more densely needle-like morphology was formed by the network of GML crystals within the oil, presenting the enhanced thermal stability due to the occurrence of van der Waals interactions and intermolecular hydrogen bonds. In turn, a more compact three-dimensional network was obtained in the emulsions with a larger droplet size, leading to a transition from a predominately elastic to viscous state. Moreover, a lower oxidation rate was observed by the POV and TBARS values as a function of storage time in either the oleogels or oleogel emulsions, indicating a better oxidative stability. These results contribute to a better understanding of oleogelation in camellia oil-based oleogels and oleogel emulsions for formulating food, pharmaceutical and person care products with desired physical properties and oxidative stability.

Self-assembled lipids for food applications: A review

Lipids play an important role in human nutrition. Several foodstuffs can be manufactured from the simple, compound and derived lipids. In particular, the use of self-assembled lipids (SLs, e.g. self-assembled L-α-lecithin) has brought great attention for the development of tailored, tuned and targeted colloidal structures loading degradation-sensitive substances with valuable antimicrobial, antioxidant and nutraceutical properties for food applications. For example, polyunsaturated fatty acids (PUFAs) and essential oils can be protected from degradation, thus improving their bioavailability in general terms in consumers. From a nanotechnological point of view, SLs allow the development of advanced and multifaceted architectures, in which each molecule of them are used as building blocks to obtain designed and ordered structures. It is important to note before beginning this review, that simple and compound lipids are the main SLs, while essential fatty acids and derived lipids in general have been considered by many research groups as the bulk loaded substances within several structures from self-assembled carbohydrates, proteins and lipids. However, this review paper is addressed on the analysis of the lipid-lipid self-assembly. Lipids can be self-assembled into various structures (micelles, vesicular systems, lyotropic liquid crystals, oleogels and films) to be used in different food applications: coatings, controlled and sustained release materials, emulsions, functional foods, etc. SLs can be obtained via non-covalent chemical interactions, primarily by hydrogen, hydrophilic and ionic bonding, which are influenced by the conditions of ionic strength, pH, temperature, among others. This manuscript aims to give an analysis of the specific state-of-the-art of SLs for food applications, based primarily on the literature reported in the past five years.

Surfactant addition to modify the structures of ethylcellulose oleogels for higher solubility and stability of curcumin

The current study developed ethylcellulose (EC) based oleogels with the addition of a surface active ingredient (sorbitan monopalmitate, SP), in order to increase the active loading of curcumin by reducing lipid oxidation, improving curcumin solubility and chemical stability. With the increase in SP content, EC oleogels had more compact gel networks with evenly distributed smaller pores. Rheological analysis revealed that the gels had shear-thinning behavior, and higher concentration of SP contributed to the systems with higher viscosity. The inclusion of SP also worked to reinforce gel strength as determined by frequency sweep, creep recovery and textural analyses. EC oleogels with higher content of SP were capable to hold more liquid oil during centrifugation, and the T₂ relaxation time was much lower as determined by NMR. Peroxide value of the oleogels was significantly lower in the systems with SP, and a SP content of 4% or 6% was effective in inhibiting lipid oxidation during storage. When curcumin was incorporated within the gel networks, its effective concentration was more retained with the addition of SP, as no curcumin crystals were detected by DSC during a 9-day storage test, and curcumin had much higher retention when exposed to UV light for 8 h.

Assembly pattern of multicomponent supramolecular oleogel composed of ceramide and lecithin in sunflower oil: self-assembly or self-sorting?

Ceramide (CER) is a novel food-grade organogelator with beneficial health effects. Lecithin (LEC) is not an effective gelator; however, it may alter the crystal morphology of the host gelator in a multicomponent system. In this paper, LEC and CER were mixed at various molar ratios in sunflower oil leading to different gelation behaviors. It was interesting since in this multicomponent system, gels formed when there was more less-effective gelator (LEC), while gels hardly formed when there was more effective gelator (CER). This drew our attention since there might not be only one kind of assembly mode between the LEC and the CER. A comprehensive rheological investigation was conducted. It was found that at specific ratios (6L4C and 5L5C), strong gels (G' > 1.0 × 105 Pa) formed with superior oil binding capacity (up to 99.84%). Meanwhile, these gels exhibited higher tolerance level to permanent deformation than the monocomponent gel. However, weak gels were observed off the optimal ratio (8L2C, 7L3C, 4L6C and 3L7C). The crystal morphology of gels drastically changed with change in gelator proportion. Short needle-like crystals and small rosette crystals were observed in 6L4C and 5L5C, respectively, while other samples exhibited spherulite-shaped crystals (8L2C, 7L3C, 4L6C, and 3L7C), which differed from any of the monocomponent gel structures (10L0C and 0L10C). Results from differential scanning calorimetry and polarized light microscopy suggested that the macroscopic properties are determined by the morphology and distribution of crystals rather than the crystallinity of the matrix. Fourier transform infrared spectroscopy results indicated the presence of van der Waals forces and the formation of hydrogen bonding between the phosphate of the LEC and the amide group of the CER. The above results indicated that the LEC and CER co-assembled at approximately equal molar ratio, and the redundant LEC or CER at other ratios self-sorted to combine with the co-assembled fibers by lateral association, leading to potentially different underlying microstructures. These multicomponent supramolecular oleogels with high tunability may further broaden their applicability in various healthy lipid-based product formats.