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

Structural and rheological properties of bigels formed with xanthan gum hydrogel and lecithin/glycerol monostearate oleogel

This study aimed to investigate the structural and rheological properties of bigels formed with xanthan gum hydrogel and lecithin/glycerol monostearate oleogel. Different ratios (7:3, 6:4, 5:5, 4:6, and 3:7, respectively) of xanthan gum hydrogel and lecithin/glycerol monostearate oleogel were used for producing bigels (BG-7:3, BG-6:4, BG-5:5, BG-4:6, and BG-3:7). Through visual appearance, inversion test, and storage stability test, all bigels showed a white creamy appearance with self-standing properties and storage stability for three weeks. According to CLSM analysis, BG-7:3, BG-6:4, and BG-5:5 formed an oleogel-in-hydrogel system, whereas BG-4:6 and BG-3:7 showed a bicontinuous system. Solvent holding capacity was >95 % for all bigels. Steady shear rheological analysis and three interval thixotropic test revealed that all bigels exhibited shear-thinning behavior and thixotropic recovery. Frequency sweep test revealed that storage modulus (G'), loss modulus (G″), and complex viscosity (η*) of bigels were remarkably increased as the ratio of oleogel fraction increased in bigels. These results suggest that bigels formed with xanthan gum hydrogel and lecithin/glycerol monostearate oleogel can be unique candidates for replacing fat in the food industry.

Characteristics and Functional Properties of Bioactive Oleogels: A Current Review

Oleogels have been a revolutionary innovation in food science in terms of their health benefits and unique structural properties. They provide a healthier alternative to traditional solid or animal fats. They have improved oxidative stability and nutritional value to maintain the desirable sensory qualities of lipid-based foods. Moreover, oleogels offer an ideal carrier for poorly water-soluble bioactive compounds. The three-dimensional structure of oleogels can protect and deliver bioactive compounds in functional food products. Bioactive compounds also affect the crystalline behavior of oleogelators, the physical properties of oleogels, and storage stability. Generally, different incorporation techniques are applied to entrap bioactive compounds in the oleogel matrix depending on their characteristics. These approaches enhance the bioavailability, controlled release, stability of bioactive compounds, and the shelf life of oleogels. The multifunctionality of oleogels extends their applications beyond fat replacements, e.g., food preservation, nutraceutical delivery, and even novel innovations like 3D food printing. Despite their potential, challenges such as large-scale production, cost efficiency, and consumer acceptance remain areas for further exploration. This review emphasizes the understanding of the relationship between the structure of oleogels and their functional properties to optimize their design in different food applications. It also highlights the latest advancements in bioactive oleogels, focusing on how they incorporate bioactive compounds such as polyphenols, essential oils, and flavonoids into oleogels. The impact of these compounds on the gelation process, storage stability, and overall functionality of oleogels is also critically examined.

Enhancing Medium-Chain Fatty Acid Delivery Through Bigel Technology

This study presents the development and characterization of medium-chain fatty acid (MCFA)-loaded bigels, using coconut oil as the MCFA source. The bigels exhibited high oil binding capacity, ranging from 87% to 98%, effectively retaining MCFAs within the matrix, with lauric acid (C12) being the main component detected within the bigels at 178.32 ± 0.10 mg/g. Physicochemical analysis, including FTIR and scanning electron microscopy, confirmed stable fatty acid incorporation and a cohesive, smooth structure. The FTIR spectra displayed O-H and C=O stretching vibrations, indicating hydrogen bonding within the matrix, while the SEM images showed uniform lipid droplet distribution with stable phase separation. Thermal stability tests showed that the bigels were stable for 5 days at 50 °C, with oil retention and structural integrity unchanged. Rheological testing indicated a solid-like behavior, with a high elastic modulus (G') that consistently exceeded the viscous modulus (G″), which is indicative of a strong internal structure. In simulated gastrointestinal digestion, the bigels achieved significantly higher MCFA retention than the pure oil, particularly in the gastric phase, with recovery percentages of 38.1% for the bigels and 1.7% for the oil (p < 0.05), suggesting enhanced bioavailability. Cell-based cytotoxicity assays showed low cytotoxicity, and permeability testing in a co-culture Caco-2/HT29-MTX model revealed a controlled, gradual MCFA release, with approximately 10% reaching the basolateral side over 6 h. These findings highlight MCFA-loaded bigels as a promising platform for nutraceutical applications; they provided stability, safety, and controlled MCFA release, with significant potential for functional foods aimed at enhancing fatty acid bioavailability.

Bioactive compounds delivery and bioavailability in structured edible oils systems

The health benefits of bioactive compounds are dependent on the amount of intake as well as on the amount of these compounds that become bioavailable and bioaccessible. Various systems have been developed to deliver and increase the bioaccessibility of bioactive compounds. This review explores the impact of gelled (oleogels, bigels, emulgels, emulsions, hydrogels, and hydrogel beads), micro-(gels, particles, spheres, capsules, emulsions, and solid lipid microparticles) and nanoencapsulated systems (nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions, liposomes, and nanoliposomes) on the digestibility and bioavailability of lipophilic and hydrophilic bioactives. Structurant molecules, the oil type, antioxidants, emulsifiers, and coatings in delivery systems with promising potential in food applications are critically discussed. The release and bio-accessibility of bioactive compounds in gelled systems are influenced by various factors, such as the type and concentration of gelators, the gelator-to-oil ratio, the type of antioxidant, the network of the system, and its hydrophobicity. The stability, bioaccessibility, and controlled release of bioactives were improved in structured emulsions. Several variables, including wall material, oil/water ratios, encapsulation process, and pH conditions, can affect the bioactives release in microencapsulated systems. Factors like coating type and core-to-wall ratio impact the stability and release of core components. The encapsulating material, the encapsulation technology, and the nature of the nanomaterials all have an impact on the bioaccessibility of nanoencapsulated systems. Nanoliposomes provide enhanced stability and absorption. In general, all encapsulated systems have shown great potential in improving the distribution and availability of bioactive compounds.

Hydrogel delivery systems of functional substances for precision nutrition

Hydrogel delivery systems based on polysaccharides and proteins have the ability to protect functional substances from chemical degradation, control/target release, and increase bioavailability. This chapter summarizes the recent progress in the utilization of hydrogel delivery systems for nutritional interventions. Various hydrogel delivery systems as well as their preparation, structure, and properties are given. The applications for the encapsulation, protection, and controlled delivery of functional substances are described. We also discuss their potential and challenges in managing chronic diseases such as inflammatory bowel disease, obesity, liver disease, and cancer, aiming at providing theoretical references for exploring novel hydrogel delivery systems and their practical prospects in precise nutritional interventions.

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

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

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.