Fabrication of Oleogels via a Facile Method by Oil Absorption in the Aerogel Templates of Protein-Polysaccharide Conjugates

Fabrication, characterization, and oxidation resistance of gelatin/egg white protein cryogel-templated oleogels through apple polyphenol crosslinking

Cryogel-templated oleogels (CTO) were fabricated via a facile polyphenol crosslinking strategy, where apple polyphenol was utilized to crosslink the gelatin/egg white protein conjugates without forming hydrogels. After freeze-drying, cryogel templates were obtained and used to construct CTO by oil absorption. Apple polyphenol crosslinking improved the emulsion-related properties with appearance changes on samples, and infrared spectroscopy further confirmed the interactions between proteins and apple polyphenol. The crosslinked cryogels presented porous microstructures (porosity of over 96 %), enhanced thermal/mechanical stabilities, and could absorb a high content of oil (14.41 g/g) with a considerable oil holding capacity (90.98 %). Apple polyphenol crosslinking also influenced the rheological performances of CTO, where the highly crosslinked samples owned the best thixotropic recovery of 85.88 %. Moreover, after the rapid oxidation of oleogels, the generation of oxidation products was effectively inhibited by crosslinking (POV: 0.48 nmol/g, and TBARS: 0.53 mg/L). The polyphenol crosslinking strategy successfully involved egg white protein and gelatin to fabricate CTO with desired physical/chemical properties. Apple polyphenol acted as both a crosslinker and an antioxidant, which provided a good reference for fabricating pure protein-based CTO.

Fabrication of enhanced aerogel template oleogels with enzyme-hydrolyzed soy protein isolate and covalent cross-linking

In recent years, the utilization of aerogel templates in oleogels to replace animal fats has garnered considerable attention due to health concerns. This study employed a "fiber-particle core-shell nanostructure model" to combine sodium carboxymethylcellulose (CMCNa) and soy protein isolate (SPI) or SPI hydrolysate (SPIH), and freeze-dried to form aerogel template, which was then dipped into oil to induce oleogels. The results showed that adding SPIH significantly improved the physicochemical properties of oleogels. The results of ζ-potential, FTIR, and rheology demonstrated a stronger binding of SPIH to CMC-Na compared to SPI. The CMC-Na-SPIH aerogels exhibited a coarser surface and denser network structure in contrast to CMC-Na-SPI aerogels, with an oil holding capacity (OHC) of up to 84.6 % and oil absorption capacity (OAC) of 47.4 g/g. The mechanical strength of oleogels was further enhanced through chemical crosslinking. Both CMC-Na-SPI and CMC-Na-SPIH oleogels displayed excellent elasticity and reversible compressibility, with CMC-Na-SPIH oleogels demonstrating superior mechanical strength. Additionally, CMC-Na-SPIH oleogels exhibited enhanced slow release of antimicrobial substances and antioxidant properties. Increasing the content of SPI/SPIH significantly improved the mechanical strength, antioxidant capacity, and OHC of the oleogels. This research presents a straightforward and promising approach to enhance the performance of aerogel template oleogels.

Biomacromolecular carriers based hydrophobic natural products for potential cancer therapy

Cancer is the second leading cause of death worldwide. It was estimated that 90 % of cancer-related deaths were attributable to the development of multi-drug resistance (MDR) during chemotherapy, which results in ineffective chemotherapy. Hydrophobic natural products plays a pivotal role in the field of cancer therapy, with the potential to reverse MDR in tumor cells, thereby enhancing the efficacy of tumor therapy. However, their targeted delivery is considered a major hurdle in their application. The advent of numerous approaches for encapsulating bioactive ingredients in the nanodelivery systems has improved the stability and targeted delivery of these biomolecules. The manuscript comprehensively analyses the nanodelivery systems of bioactive compounds with potential cancer therapy applications, including liposomes, emulsions, solid lipid nanoparticles (NPs), and polymeric NPs. Then, the advantages and disadvantages of various nanoagents in the treatment of various cancer types are critically discussed. Further, the application of multiple-compbine delivery methods to overcome the limitations of single-delivery have need critically analyzed, which thus could help in the designing nanodrug delivery systems for bioactive compounds in clinical settings. Therefore, the review is timely and important for development of efficient nanodelivery systems involving hydrophobic natural products to improve pharmacokinetic properties for effective cancer treatment.

Alginate Cryogels as a Template for the Preparation of Edible Oleogels

A high consumption of solid fats is linked to increased inflammation and a risk of cardiovascular diseases. Hence, in recent years, there has been increasing interest in the development of oleogels as a fat substitute in food products. Oleogels are edible gels that contain a large amount of liquid oils entrapped in a 3D network and that can potentially be applied to spreads, bakery goods, meat, and dairy products in order to lower their saturated fat content while maintaining a desirable food texture and mouthfeel. In this work, alginate cryogels were studied as templates for three different edible oils in the process of oleogel formation. Two different freezing regimes to obtain cryogels were employed in order to evaluate better the textural and morphological capabilities of cryogels to adsorb and retain edible oils. It was shown that rapid freezing in liquid nitrogen produces alginate cryogels with a lower density, higher porosity, and a greater ability to adsorb the tested oils. The highest uptake and holding oil capacity was achieved for olive oil, which reached a value of 792% and 82%, respectively. The best chewiness was found for an oleogel containing olive oil, whereas oleogels with the other two tested oils showed better springiness. Hence, the results presented in this work demonstrated that alginate-based cryogels can be effectively used as templates for oleogels and potentially find applications in the food industry.

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

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

Unravelling the functionality of anionic and non-ionic plant seed gums on milk protein cryogels conveying Lacticaseibacillus rhamnosus GG

Cryogels offer a promising macroporous platform that can be employed as either a functional ingredient in food composites or a colloidal template for incorporating bioactives, including probiotic living cells. The aim of the present work is to explore the functionality of two plant seed polysaccharides, flaxseed gum (FG) and alfalfa galactomannan (AAG), in individual and combined (1:1 ratio) milk protein-based cryogels, namely sodium caseinate (NaCas) and whey protein isolate (WPI). These cryogels were created by freeze-drying hydrogels formed via L.rhamnosus GG - a human gut-relevant probiotic strain - fermentation. Our findings showed that including gum in the composition limited volume contraction during lyophilisation, reduced macropore size and thickened cryogel skeleton vessels. Furthermore, gum-containing cryogels displayed improved thermal stability and slower water disintegration rates. The AAG-stabilised cryogels specifically showed a notable reduction in monolayer water content compared to FG. From a mechanistic viewpoint, AAG influenced the physicochemical and microstructural properties of the cryogels, most probably via its self-association during cryogenic processing, promoting the development of intertwined protein-gum networks. FG, on the other hand, enhanced these properties through electrostatic complexation with proteins. Cryogels made from protein-polysaccharide blends exhibited promising techno-functional properties for enhancing and diversifying food product innovation.

Construction of a multifunctional dual-network chitosan composite aerogel with enhanced tunability

Typically, the tailorable versatility of biomass aerogels is attributed to the tunable internal molecular structure, providing broad application prospects. Herein, a simple and novel preparation strategy for developing multifunctional dual-network chitosan/itaconic acid (CSI) aerogel with tunability by using freeze-drying and vacuum heat treatment techniques. By regulating the temperature and duration of amidation reaction, electrostatic interactions between chitosan (CS) and itaconic acid (IA) was abstemiously converted into amide bond in frozen aerogel, with IA acting as an efficient in-situ cross-linking agent, which yielded CSI aerogels with different electrostatic/covalent cross-linking ratios. Heat treatment and tuning of the covalent cross-linking degree of CSI aerogel changed their microstructure and density, which led to enhanced performance. For example, the specific modulus of CSI1.5-160 °C-5 h (71.69 ± 2.55 MPa·cm3·g-1) increased by 119 % compared to that of CSI1.5 (32.73 ± 0.718 MPa·cm3·g-1), converting the material from superhydrophilic to hydrophobic (124° ± 3.6°), exhibiting favorable stability and heat transfer performance. In addition, part of -NH3+ of CS was retained in the electrostatic cross-linked network, endowing the aerogel with antibacterial properties. The findings of this study provide insights and a reliable strategy for fabricating biomass aerogel with good comprehensive performance via ingenious structural design and simple regulation methods.

Microencapsulation of green coffee oil by complex coacervation of soy protein isolate, sodium casinate and polysaccharides: Physicochemical properties, structural characterisation, and oxidation stability

This study developed a combination method between protein-polysaccharide complex coacervation and freezing drying for the preparation of green coffee oil (GCO) encapsulated powders. Different combinations of soy protein isolate, sodium caseinate, sodium carboxymethylcellulose, and sodium alginate were utilised as wall materials. The occurrence of complexation between the biopolymers were compared to the final emulsion of the individual protein and confirmed by fourier transform infrared spectrometry and X-ray diffraction. The mean diameter and estimated PDI of GCO microcapsules were 72.57-295.00 μm and 1.47-2.02, respectively. Furthermore, the encapsulation efficiency of GCO microcapsules was between 61.47 and 90.01 %. Finally, oxidation kinetics models of GCO and its microcapsules demonstrated that the zero-order model of GCO microcapsules was found to have a higher fit, which could better reflect the quality changes of GCO microcapsules during storage. Different combinations of proteins and polysaccharides exhibited effective oxidative stability against single proteins because of polysaccharide addition. This research revealed that soy protein isolate, sodium caseinate combined with polysaccharides can be used as a promising microencapsulating agent for microencapsulation of GCO, especially with sodium carboxymethylcellulose and sodium alginate, and provided useful information for the potential use of GCO in the development of powder food.

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

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

Characterization of chitosan-gelatin cryogel templates developed by chemical crosslinking and oxidation resistance of camellia oil cryogel-templated oleogels

In this study, chitosan-gelatin conjugates were prepared by chemical crosslinking of tannic acid. The cryogel templates were developed through freeze-drying and immersed in camellia oil to construct cryogel-templated oleogels. Chemical crosslinking resulted in apparent colour changes and improved emulsion-related/rheological properties on conjugates. The cryogel templates with different formulas exhibited different microstructures with high porosities (over 96 %), and crosslinked samples might have higher hydrogen bonding strength. Tannic acid crosslinking also led to enhanced thermal stabilities and mechanical properties. Cryogel templates could reach a considerable oil absorption capacity of up to 29.26 g/g and prevent oil from leaking effectively. The obtained oleogels with high tannic acid content possessed outstanding antioxidant abilities. After 8 days of rapid oxidation at 40 °C, Oleogels with a high degree of crosslinking owned the lowest POV and TBARS values (39.74 nmol/kg, and 24.40 μg/g, respectively). This study indicates that the involvement of chemical crosslinking would favor the preparation and the application potential of cryogel-templated oleogels, and the tannic acid in the composite biopolymer systems could act as both the crosslinking agent and the antioxidant.

Bigels constructed from hybrid gelator systems: bulk phase-interface stability and 3D printing

In this study, edible bigels with different ratios of beeswax-based oleogel to gellan gum-based hydrogel were developed and characterized. Gellan gum formed a 3D network in water through hydrogen bonding. Beeswax formed a crystalline network in the oil phase, which prevented the flow of oil and formed an oleogel. The position of the droplets is fixed by the crystallization of glycerol monostearate (GMS) at the interface. Bigels with different oleogel contents presented different types of O/W (oleogel content was less than 62%), semi-bicontinuous (oleogel content was 62-68%), and W/O bigels (oleogel content was more than 70%), respectively. Rheological experiments showed bigels had a shear thinning ability, which was suitable for extrusion 3D printing. Then the applicability of 3D printing was studied and it was found that the self-supporting ability of bigels became stronger with the increase of oleogel content. Functional pigments were incorporated into the bigel inks, making the 3D printing product nutrient-rich and color customizable. These results would favor guiding the preparation of bigels with adjusted physical properties and delicate structures for 3D food printing to satisfy the personal desire of consumers.

Covalent Bond Interfacial Recognition of Polysaccharides/Silica Reinforced High Internal Phase Pickering Emulsions for 3D Printing

Significant challenges remain in designing sufficient viscoelasticity polysaccharide-based high internal phase Pickering emulsions (HIPPEs) as soft materials for 3D printing. Herein, taking advantage of the interfacial covalent bond interaction between modified alginate (Ugi-OA) dissolved in the aqueous phase and aminated silica nanoparticles (ASNs) dispersed in oil, HIPPEs with printability were obtained. Using multitechniques coupling a conventional rheometer with a quartz crystal microbalance with dissipation monitoring, the correlation between interfacial recognition coassembly on the molecular scale and the stability of whole bulk HIPPEs on the macroscopic scale can be clarified. The results showed that Ugi-OA/ASNs assemblies (NPSs) were strongly retargeted into the oil-water interface due to the specific Schiff base-binding between ASNs and Ugi-OA, further forming thicker and more rigid interfacial films on the microscopic scale compared with that of the Ugi-OA/SNs (bared silica nanoparticles) system. Meanwhile, flexible polysaccharides also formed a 3D network that suppressed the motion of the droplets and particles in the continuous phase, endowing the emulsion with appropriately viscoelasticity to manufacture a sophisticated "snowflake" architecture. In addition, this study opens a novel pathway for the construction of structured all-liquid systems by introducing an interfacial covalent recognition-mediated coassembly strategy, showing promising applications.

Emerging Trends in Nanotechnology: Aerogel-Based Materials for Biomedical Applications

At present, aerogel is one of the most interesting materials globally. The network of aerogel consists of pores with nanometer widths, which leads to a variety of functional properties and broad applications. Aerogel is categorized as inorganic, organic, carbon, and biopolymers, and can be modified by the addition of advanced materials and nanofillers. Herein, this review critically discusses the basic preparation of aerogel from the sol-gel reaction with derivation and modification of a standard method to produce various aerogels for diverse functionalities. In addition, the biocompatibility of various types of aerogels were elaborated. Then, biomedical applications of aerogel were focused on this review as a drug delivery carrier, wound healing agent, antioxidant, anti-toxicity, bone regenerative, cartilage tissue activities and in dental fields. The clinical status of aerogel in the biomedical sector is shown to be similarly far from adequate. Moreover, due to their remarkable properties, aerogels are found to be preferably used as tissue scaffolds and drug delivery systems. The advanced studies in areas including self-healing, additive manufacturing (AM) technology, toxicity, and fluorescent-based aerogel are crucially important and are further addressed.

Optimization of Olive Oil Oleogel-Based Emulsion Composition: Effect of Oleogel Composition on Emulsion Characteristics

In this study, the effects of oil, water, glycerol monostearate, carrageenan and alginate concentrations, which have a significant effect on quality parameters in olive oil oleogel-based emulsion (OOE), were investigated and their optimum amounts were determined by mixture design for oleogel production with desired properties. OOE was produced using olive oil, water, glycerol monostearate (GMS), carrageenan and alginate at various concentrations in the range of 0-70%, 30-60%, 0-2%, 0-2% and 0-2%, respectively. The optimum quality parameters of OOE were evaluated in terms of optimum firmness value (5.5-7 N), minimum oil loss and peroxide value. The optimum composition was determined 53.5% olive oil, 43.5% water, 1.1% carrageenan, 0.92% alginate and 0.98% glycerol monostearate (w/w). Produced OOE under determined optimum conditions had 5.81 N firmness, 1.82 meq/O₂ peroxide value and 21.02% oil loss value. The margin of error between the experimentally obtained data and the estimated data in the study is average 2%. The results showed that the formulation used in OOE production have significant effects on the created OOE structure and quality parameters. In addition, different formulations to be created with the results of the present study will contribute to increasing the applicability of OOE in different foods.

Thermal-reversible lacquer wax-based oleofoams in dual stabilization with high ambient stability

In this study, the effect of the content of the lacquer wax and whipping time on the overrun was explored. It was found that an appropriate amount of wax content and whipping time could promote crystal dual stabilization through the Pickering mechanism and the close packing in the bulk phase. Otherwise, it would result in low overrun caused by high viscous and crystal bridging. The addition of polyglycerol polyricinoleate (PGPR) could effectively enhance the overrun by apace absorbing. At the same time, adding PGPR also improved the contact angle, which was beneficial to the adsorption at the A-O interface. The 8 wt% oleogel was partially substituted by high-melting fat palm stearin (POs) and oleofoams were prepared based on blended fat. POs increased the melting point, structural strength, and β'-form crystal of oleofoams, thus improving the storage and temperature stability. The oleofoam has a maximum overrun of 189% and could maintain the shape of the decorating over 15 d at the ambient temperature, showing great potential in low-fat food applications and other delivery systems.

Ultrathin Cellulose Nanofiber Assisted Ambient-Pressure-Dried, Ultralight, Mechanically Robust, Multifunctional MXene Aerogels

Ambient-pressure-dried (APD) preparation of transition metal carbide/nitrides (MXene) aerogels is highly desirable yet remains highly challenging. Here, ultrathin, high-strength-to-weight-ratio, renewable cellulose nanofibers (CNFs) are efficiently utilized to assist in the APD preparation of ultralight yet robust, highly conductive, large-area MXene-based aerogels via a facile, energy-efficient, eco-friendly, and scalable freezing-exchanging-drying approach. The strong interactions of large-aspect-ratio CNF and MXene as well as the biomimetic nacre-like microstructure induce high mechanical strength and stability to avoid the structure collapse of aerogels in the APD process. Abundant functional groups of CNFs facilitate the chemical crosslinking of MXene-based aerogels, significantly improving the hydrophobicity, water resistance, and even oxidation stability. The ultrathin, 1D nature of the CNF renders the minimal MXenes' interlayered gaps and numerous heterogeneous interfaces, yielding the excellent conductivity and electromagnetic interference (EMI) shielding performance of aerogels. The synergies of the MXene, CNF, and abundant pores efficiently improve the EMI shielding performance, photothermal conversion, and absorption of viscous crude oil. This work shows great promises of the APD, multifunctional MXene-based aerogels in electromagnetic protection or compatibility, thermal therapy, and oil-water separation applications.

Edible oleogels based on high molecular weight oleogelators and its prospects in food applications

Food industry is actively looking for alternative ingredients to replace saturated and trans fats in foods while preserving their original organoleptic attributes to ensure consumers' acceptance. A plausible approach is the replacement of solid fats with oleogels. Oleogels can be engineered to mimic properties that are commonly played by regular solid fats but using hydrophobic liquid vegetable oil with an optimum fatty acid profile and, they can also act as carriers for lipophilic bioactive substance. Low molecular weight oleogelators (LMOGs) are well studied and reviewed. In contrast, high molecular weight oleogelators (HMOGs) e.g., polysaccharides and proteins, are not fully researched yet. This review focusses on development of HMOG oleogels produced by means of emulsion templated, direct dispersion, foam templated and solvent exchange methods that can influence the stability, physicochemical properties and their potential application in food industry. Multi-component oleogels can solve the inefficiencies in a single component oleogel and, thus, combinations of HMOGs and HMOGs & LMOGs can produce oleogels with desired properties. These new oleogels can find application as fat substitutes in food products, providing better nutritional and sensory acceptance. A comprehensive overview of recent developments in the field of HMOG and multicomponent oleogels with HMOG is deeply reviewed.

Effects of Polysaccharide Concentrations on the Formation and Physical Properties of Emulsion-Templated Oleogels

An emulsion template method was an effective way to prepare oleogels. However, there were few reports on how hydroxypropyl methylcellulose-pectin (HPMC-PC) mixtures affected the physicochemical properties of the obtained oleogels. In this study, the oleogels were prepared by an emulsion template method. The influences of HPMC and PC concentrations on the formation and physical properties of the emulsions and oleogels were investigated, by analyzing particle size distribution, microstructure, rheological test, oil loss, and crystallinity. The results of particle sizes and microstructure showed that a high concentration of HPMC and PC exhibited a better emulsification performance. The rheological tests indicated that a high concentration of HPMC and PC contributed to an increase in the mechanical strength of emulsions and oleogels. Moreover, an increase in an HPMC and PC concentration was beneficial to reduce the oil loss of oleogels. However, the change of HPMC and PC concentrations had no significant effect on the X-ray diffraction pattern of oleogels. This study could provide a theoretical basis for the construction of polysaccharide-based oleogels.

Double network oleogels co-stabilized by hydroxypropyl methylcellulose and monoglyceride crystals: Baking applications

Edible double network oleogels were prepared by hydroxypropyl methylcellulose (HPMC) and glyceryl monostearate (GMS) by the cryogel-templated method. Hot GMS soybean oil solutions were absorbed by HPMC cryogels, which were further homogenized and cooled to form oleogels containing both the HPMC network and GMS network. The crystal network constructed by GMS crystal clusters significantly enhanced the mechanical and rheological attributes of oleogels. Both the HPMC network and the GMS network were built up due to hydrogen bonds. According to the normalization analysis of FTIR and the deepening of the shift of the absorption peak, hydrogen bonds could also be formed between HPMC and GMS to connect the two independent networks. Double network oleogels were further used to fabricate cookies and cakes, assessed by the texture profile analysis. The combination of the HPMC network and GMS network in preparing oleogels will promote the application of oleogels as the fat replacer.

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.

Bio-aerogels: Fabrication, properties and food applications

Traditional inorganic aerogels sustainability, biodegradability, and environmental safety concerns have driven researchers to find their safe green alternatives. Recently, interest in the application of bio-aerogels has rapidly increased in the food industry due to their unique characteristics such as high specific surface area and porosity, ultralow density, tunable pore size and morphology, and superior properties (physicochemical, mechanical, and functional). Bio-aerogels, a special category of highly porous unique materials, fabricated by the sol-gel method followed by drying processes, comprising three-dimensional networks of interconnected biopolymers (e.g., polysaccharides and proteins) with numerous air-filled pores. The production of bio-aerogels begins with the formation of a homogeneously dispersed precursor solution, followed by gelation and wet gel drying procedures by employing special drying techniques including atmospheric-, freeze-, and supercritical drying. Due to their special properties, bio-aerogels have emerged as sustainable biomaterial for many industrial applications, i.e., encapsulation and controlled delivery, active packaging, heavy metals separation, water and air filtration, oleogels, and biosensors. Bio-aerogels are low-cost, biocompatible, and biodegradable sustainable material that can be used in improving the processing, storage, transportation, and bioavailability of food additives, functional ingredients, and bioactive substances for their health benefits with enhanced shelf-life.

Alginate-based delivery systems for food bioactive ingredients: An overview of recent advances and future trends

Due to its advantagessuch as ionic crosslinking, pH responsiveness, excellent biocompatibility, biodegradability and low price, alginate has become one of the most important natural polysaccharides extensively used in constructing desired delivery systems for food bioactive ingredients. In this review, the fundamental knowledge of alginate as a building block for construction of nutraceutical delivery systems is introduced. Then, various types of alginate-based nutraceutical delivery systems are classified and summarized. Furthermore, the future trends of alginate-based delivery systems are highlighted. Currently, alginate-based delivery systems include hydrogel, emulsion, emulsion-filled alginate hydrogel, nanoparticle, microparticle, core-shell particle, liposome, edible film, and aerogel. Although alginate has been widely used in the fabrication of food bioactive ingredient delivery systems, further efforts and improvements are still needed. For this purpose, the future perspectives of alginate-based delivery systems are discussed. The feasible research trends of alginate-based delivery systems include the development of novel large-scale commercial preparation technology, multifunctional delivery system based on alginate, alginate oligosaccharide-based delivery system and alginate-based oleogel. Overall, the objective of this review is to provide useful guidance for rational design and application of alginate-based nutraceutical delivery systems in the future.

Tailoring the Structure of Lipids, Oleogels and Fat Replacers by Different Approaches for Solving the Trans-Fat Issue-A Review

The issue of the adverse effects of trans-fatty acids has become more transparent in recent years due to researched evidence of their link with coronary diseases, obesity or type 2 diabetes. Apart from conventional techniques for lipid structuring, novel nonconventional approaches for the same matter, such as enzymatic interesterification, genetic modification, oleogelation or using components from nonlipid origins such as fat replacers have been proposed, leading to a product with a healthier nutritional profile (low in saturated fats, zero trans fats and high in polyunsaturated fats). However, replacing conventional fat with a structured lipid or with a fat mimetic can alternate some of the technological operations or the food quality impeding consumers' acceptance. In this review, we summarize the research of the different existing methods (including conventional and nonconventional) for tailoring lipids in order to give a concise and critical overview in the field. Specifically, raw materials, methods for their production and the potential of food application, together with the properties of new product formulations, have been discussed. Future perspectives, such as the possibility of bioengineering approaches and the valorization of industrial side streams in the framework of Green Production and Circular Economy in the production of tailored lipids, have been highlighted. Additionally, a schematic diagram classifying conventional and nonconventional techniques is proposed based on the processing steps included in tailored lipid production as a convenient and straightforward tool for research and industry searching for healthy, sustainable and zero trans edible lipid system alternatives.

Recent advances on food-grade oleogels: Fabrication, application and research trends

In order to improve the nutritional and quality characteristics of food, solid fats are widely used in food formulations. With the continuous improvement of consumers' awareness of health in recent years, substantial attempts have been carried out to find substitutes for solid fats to reduce saturated fatty acid content in foods. Oleogels have drawn increasing attention due to their attractive advantages such as easy fabrication, superior fatty acid composition and safe use in food products to satisfy consumers' demands for healthy products. This review provides the latest information on the diversified oleogel systems. The feasibility of oleogel and oleogel-based system as nutraceutical vehicles is elucidated. The type as well as concentration of oleogelators and the synergistic effect between two or more oleogelators are important factors affecting the properties of obtained oleogel. Oleogels used in nutraceutical delivery have been shown to offer increased loading amount, enhanced bioaccessibility and targeted or controlled release. These nutrients wrapped in oleogels may in turn affect the formation and properties of oleogels. Furthermore, the future perspectives of oleogels are discussed. The feasible research trends of food-grade oleogel include oleogel-based solid lipid particle, essential oil-in-oleogel system, delivery of probiotics, nutraceuticals co-delivery and microencapsulated oleogel.

Enhanced physical and antimicrobial properties of alginate/chitosan composite aerogels based on electrostatic interactions and noncovalent crosslinking

In this study, the alginate/chitosan composite aerogels based on electrostatic interactions and noncovalent crosslinking were fabricated using sol-gel method followed by freeze-drying process. The solution property results showed that with the addition of chitosan in alginate solution, a tighter network was induced by the more entangled molecular chains. The aerogel morphology observations showed that the pore diameter decreased with the increasing weight ratio of chitosan in the aerogels, but was even much lower after the crosslinking of excess alginate with calcium ions. After crosslinking, the aerogels presented the improved thermal stability and higher mechanical properties, as well as stronger antibacterial activities against Staphylococcus aureus and Escherichia coli. Therefore, the enhanced physical and antimicrobial properties of the alginate/chitosan aerogels may be achieved by modulation of electrostatic interactions and noncovalent crosslinking, suggesting the promising applications of these composite aerogels as active food packaging materials for antimicrobial purpose.

Recent Progress in Polysaccharide Aerogels: Their Synthesis, Application, and Future Outlook

Porous polysaccharides have recently attracted attention due to their porosity, abundance, and excellent properties such as sustainability and biocompatibility, thereby resulting in their numerous applications. Recent years have seen a rise in the number of studies on the utilization of polysaccharides such as cellulose, chitosan, chitin, and starch as aerogels due to their unique performance for the fabrication of porous structures. The present review explores recent progress in porous polysaccharides, particularly cellulose and chitosan, including their synthesis, application, and future outlook. Since the synthetic process is an important aspect of aerogel formation, particularly during the drying step, the process is reviewed in some detail, and a comparison is drawn between the supercritical CO2 and freeze drying processes in order to understand the aerogel formation of porous polysaccharides. Finally, the current applications of polysaccharide aerogels in drug delivery, wastewater, wound dressing, and air filtration are explored, and the limitations and outlook of the porous aerogels are discussed with respect to their future commercialization.

Structural characterization of modified whey protein isolates using cold plasma treatment and its applications in emulsion oleogels

Cold plasma as a green and expeditious tool was used to modify whey protein isolate (WPI) in order to improve its emulsion capability. The emulsion-based oleogels with antibacterial functions were then constructed using the modified WPI. The modified WPI treated with cold plasma under 10 s at 50 W power significantly lowered the oil-water interface tension. Meanwhile, the fluorescence intensity and the α-helix content of WPI reduced with the cold plasma treatment. It is noted that SEM results showed that the treated WPI had more regular dendritic structures. Such modified WPI was applied to construct oleogels loaded with thyme essential oil and coconut oil, which showed a porous uniform network structure and excellent antimicrobial activities against E.coli. As a proof of concept, this study demonstrated cold plasma could be as a new facile tool to modify food-sourced proteins and expected to enlarge their applications in oleogel productions.

Multifunctional Photothermal Conversion Nanocoatings Toward Highly Efficient and Safe High-Viscosity Oil Cleanup Absorption

Efficient and safe cleanup for the high-viscosity heavy oil spill has been a worldwide challenge due to its sluggish flowability, while classic absorption methods by electric/solar heating are seriously limited by low efficiency and high fire hazards during heating of highly flammable oil. Facing this dilemma, we reported a novel flame-retardant photothermal conversion nanocoating to endow commercial foams with highly efficient and safe heavy oil cleanup absorption. This multifunctional nanocoating consisting of nano-Fe₃O₄ and reduced graphene oxide (rGO) that both showed photothermal conversion ability and non-flammable nature can be firmly deposited on the polymer foam skeletons via facile coprecipitation and dip-coating processes. The composite foam showed a tough morphology with high hydrophobicity and low density, thus leading to selective high absorption for various oils and organic solvents. Due to the double photothermal conversion effects of nano-Fe₃O₄ and rGO, the temperature of the foam can be rapidly heated at a rate of ∼103.5 °C/min (the fastest rate ever) under 1 sun irradiation. Consequently, the foam with a high absorption capacity of 75.1 times its weight demonstrated a rapid absorption rate of 9000 g m^-2 min^-1 for large-viscosity oil under 1 sun irradiation, which was 3 times faster than previously reported. Furthermore, benefitting from high flame retardancy, elasticity, and magnetism, the foam can be safely and repeatedly used for magnetically controllable oil cleanup absorption, which effectively avoids oil spill hazards.