Glycolipid-Based Oleogels and Organogels: Promising Nanostructured Structuring Agents

Self-Assembling Nanoarchitectonics of Twisted Nanofibers of Fluorescent Amphiphiles as Chemo-Resistive Sensor for Methanol Detection

The inhalation, ingestion, and body absorption of noxious gases lead to severe tissue damage, ophthalmological issues, and neurodegenerative disorders; death may even occur when recognized too late. In particular, methanol gas present in traces can cause blindness, non-reversible organ failure, and even death. Even though ample materials are available for the detection of methanol in other alcoholic analogs at ppm level, their scope is very limited because of the use of either toxic or expensive raw materials or tedious fabrication procedures. In this paper, we report on a simple synthesis of fluorescent amphiphiles achieved using a starting material derived from renewable resources, this material being methyl ricinoleate in good yields. The newly synthesized bio-based amphiphiles were prone to form a gel in a broad range of solvents. The morphology of the gel and the molecular-level interaction involved in the self-assembly process were thoroughly investigated. Rheological studies were carried out to probe the stability, thermal processability, and thixotropic behavior. In order to evaluate the potential application of the self-assembled gel in the field of sensors, we performed sensor measurements. Interestingly, the twisted fibers derived from the molecular assembly could be able to display a stable and selective response towards methanol. We believe that the bottom-up assembled system holds great promise in the environmental, healthcare, medicine, and biological fields.

Formation and application of edible oleogels prepared by dispersing soy fiber particles in oil phase

Oleogels containing less saturated and trans-fats were considered as an ideal option to replace the solid fats in foods. In this research, oleogel was fabricated by dispersing soy fiber particles (SFP) in soy oil, and further it was used in bread preparation. Effect of the particle size, particle content and the second fluid content on the formation of oleogels were evaluated, based on the appearance and rheological properties. Results showed that the suspension of SFP in soy oil (24%, w/w) could be transformed into gel-like state, upon the addition of the second fluid. The SFP based networks were dominated by the capillary force which was originated from the second fluid. The rheological properties and yield stress of the oleogels could be modulated by particle size and particle content of SFP in oil phase, as well as the second fluid content in the system. When the oleogels were applicated in bread preparation, a layered structure could be formed in the bread, indicating the possibility of replacing the solid fats in bakery products by our oleogels. Our results offered a feasibility approach for oil structuring with natural raw materials, and developed a new approach to replace the solid fats in foods.

Sustainable Production of Novel Oleogels Valorizing Microbial Oil Rich in Carotenoids Derived from Spent Coffee Grounds

Sustainable food systems that employ renewable resources without competition with the food chain are drivers for the bioeconomy era. This study reports the valorization of microwave-pretreated spent coffee grounds (SCGs) to produce oleogels rich in bioactive compounds. Microbial oil rich in carotenoids (MOC) was produced under batch fermentation of Rhodosporidium toruloides using SCG enzymatic hydrolysates. Candelilla wax (CLW) could structure MOC and sunflower oil at a 3.3-fold lower concentration than that of carnauba wax (CBW). MOC-based oleogels with 10% CBW and 3% CLW showed an elastic-dominant and gel-like structure (tan δ ≪ 1), providing gelation and oil binding capacity (>95%). Dendritic structures of CBW-based oleogels and evenly distributed rod-like crystals of CLW-based ones were observed via polarized light microscopy. MOC-based oleogels exhibited similar Fourier-transform infrared spectroscopy spectra. X-ray diffractograms of oleogels were distinguished by the oil type that presented β'-type polymorphism. MOC-based oleogels could be applied in confectionary products and spreads as substitutes for trans fatty acids, reformulating fat-containing food products.

Supramolecular Glycolipid-Based Hydro-/Organogels with Enzymatic Bioactive Release Ability by Tuning the Chain Length and Headgroup Size

Designing of supramolecular hydro-/organogels having desired properties, biocompatibility, and stimuli responsiveness is a challenging task. Herein, the gelation ability of amphiphilic glycolipid-based gelators in a wide range of solvents is explored. The structure-function relationship was established by varying the chain length and polar headgroup size of amphiphilic gelators. The prepared hydro-/organogels were characterized by employing several techniques such as differential scanning calorimetry (DSC), rheology, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), etc. The thermal stability of hydro-/organogels increased with an increase in chain length. Rheological analysis depicted that variation in chain length and headgroup size of amphiphilic gelators significantly affected the gel strength and stability. The self-assembled morphology of hydro-/organogel samples revealed the compact entangled fibrillar network structures. After comparing the energy-minimized molecular length with the d-spacing value obtained by XRD, interdigitated bilayer packing in the gel network was established. The bioactive encapsulation and enzymatic release study of hydro-/organogels portrayed their potential application in the biomedical field. To our delight, glycolipid 16M (C16 chain length) formed a molecular hydrogel with injectable and thixotropic behaviors. High critical strain value, thixotropy, injectability, thermoreversibility, and faster bioactive release for the 16M-W hydrogel proved crucial to predict its future applications. Overall, glycolipid amphiphiles designed by upholding proper hydrophilic-lipophilic balance can form multifunctional supramolecular hydrogels with excellent implementation in the drug delivery system.

Hybrid hydrogels derived from renewable resources as a smart stimuli responsive soft material for drug delivery applications

The design and synthesis of amphiphilic molecules play a crucial role in fabricating smart functional materials via self-assembly. Especially, biologically significant natural molecules and their structural analogues have inspired chemists and made a major contribution to the development of advanced smart materials. In this report, a series of amphiphilic N-acyl amides were synthesized from natural precursors using a simple synthetic protocol. Interestingly, the self-assembly of amphiphiles 6a and 7a furnished a hydrogel and oleogel in vegetable oils. Morphological analysis of gels revealed the existence of a 3-dimensional fibrous network. Thermoresponsive and thixotropic behavior of these gels were evaluated using rheological analysis. A composite gel prepared by the encapsulation of curcumin in the hydrogel formed from 7a displayed a gel–sol transition in response to pH and could act as a dual channel responsive drug carrier.

The design and synthesis of amphiphilic molecules play a crucial role in fabricating smart functional materials via self-assembly.

Investigation on the surface-active and antimicrobial properties of a natural glycolipid product

Glycolipids are a group of sugar-containing lipids with versatile functions. In this study, a natural glycolipid product was obtained from soy lecithin, and its emulsifying, oil-gelling, antibacterial and antiviral properties were investigated. A silica-based extraction method on a preparative scale was used to recover the glycolipid product (GLP) from soy lecithin. The GLP consisted of three different glycolipid classes: acylated sterol glucoside (64.16%), sterol glucoside (25.57%) and cerebroside (6.71%). As an emulsifier, the GLP was able to form a stable water-in-oil emulsion. The GLP exhibited a good oil-gelling property, capable of gelling rapeseed oil at a concentration of 6%. For the investigated microorganisms (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus), the GLP did not show any antibacterial effects. The GLP exerted antiviral activity against lentivirus, but not adenovirus. The results of this study help in enriching the knowledge on the properties of naturally occurring glycolipids, which may find potential applications in the food, pharmaceutical and related industries.