True Gel Research Articles

Designation and characterization of cold-set whey protein isolate-low acyl gellan gum emulsion-filled gel for enhancing limonene flavor perception: A study on structure, breakdown characteristics, and sensory perception in the human mouth

Flavor perception depends on food structure and oral processing behavior. Emulsion-filled gel (EFG) is a category of soft to solid food products that utilizes the advantages of emulsions to deliver lipid-soluble ingredients, such as the limonene flavor. This paper aimed to design a cold-set EFG system as a carrier to improve limonene flavor perception using whey protein isolate and low-acyl gellan gum (LAGG) (0–0.7% w/w). With increasing LAGG levels, the EFGs shifted towards forming a true gel structure with a brittle and hard 3D network based on the steady shear, amplitude (increasing GLVE′ and decreasing tanδLVE), frequency sweep (increasing K′ and decreasing n′), and uniaxial compassion (increasing Young's modulus and decreasing fracture strain) tests. EFG with 0.7% LAGG needed a higher chewing process, and the fragmentation increased as EFG hardness increased. According to the time-intensity test, the highest and lowest limonene perception were found in the EFG-contained 0.3% (Imax: 5.14, area: 79.20) and 0.7% (Imax: 4.35, area: 57.40) LAGG. In conclusion, by manipulating the structure, custom architectures can be created in the oral cavity, resulting in specific performance and controlled release of their components.

Steady and dynamic shear rheology of aqueous solutions of quince seed gum combinations with locust bean or xanthan gums

This study presents the rheological properties of quince seed gum (Q) solution in comparison with xanthan gum (X) and locust bean gums (L) and the polymeric interactions of different ratios of Q:X and Q:L blends (1:1, 1:3 and 3:1). Q exhibits greater and stronger elastic properties than X and L. The frequency and temperature stability of Q and X are both higher than that of L. The viscoelastic properties of Q:X and Q:L solutions were found to be higher than those of the individual solutions. The higher polymer entanglements observed in Q:L blends resulted in enhanced synergistic interactions and thixotropy compared to Q:X. 3QX exhibited an enhanced elastic structure, but the best synergism was observed for 3QL due to the establishment of a stronger intermolecular bond for gelling. The lower tan δ observed with increasing Q indicate a Q-induced synergistic interaction with L. At all temperatures, 3QL showed the highest thixotropy. The combination of Q and L resulted in the formation of a true gel, with the higher gel strength being observed for QL and 3QL. This study shows that Q:L and Q:X combinations can yield desired flow properties. In particular, L provides a firmer gel network with Q.

Direct Observation of Transient Flow Kinematics of Environment-Friendly Silica-Based Alcogel at Instantaneous Gelation

This study was intended to exploit the possibility of using the quick gelation of alcogel that is induced by adding catalytic imidazole into a silicate-oligomer-based solution. For this purpose, the experimental viability of the direct observation of the gelation behavior was actually examined. The silicate oligomer, derived from tetraethyl orthosilicate hydrolyzed under an acidic condition (pH ~ 5), was used as the quickly gelling mother solution. The capability of the oligomer solution to form a non-flowable matter in only a few seconds when triggered by the addition of the catalytic solution of imidazole is promising, for example, for stabilizing a sandy ground surface, due to its simplicity. From the practical viewpoint, how long the gelation could take (=gel time) is a crucial parameter when the choice of an appropriate gelling chemical species needs to be made. Thus, this study focused its interest on as simple an experimental method as possible for evaluating the gel time of the gelling systems that actually underwent instantaneous gelation. The silicate oligomer solution was an appropriate material both in its quick gelling behavior and environmental friendliness. For such quick gelation, rheological approaches are not applicable for detecting the boundary in the mechanical properties that delineate the regime of “gel”. In this study, instead, direct observation was employed to capture the short interval during which the gelation was completed. The silicate-oligomer-based gelling solution was observed to lose its flowability within only 0.2 s, as it was seen to come off the bottom of the shaken cylinder at 5 Hz. For a more quantitative estimation, the same gelling solution was observed by high-speed motion picture. The high-speed motion picture could clearly capture the instantaneous gelation as a sudden arrest of the flow. The sub-millisecond direct observation of the gelation behavior revealed that the timescale of the instantaneous termination of the flow was as quick as 1 ms in order of magnitude. Such instantaneous gelation in the sub-millisecond-order timescale could not be forecasted from the observable megascopic gelation, which appeared to last from 102 ms to 103 ms in our naked-eye observation. The noteworthy gap between the timescale of the naked-eye-observed gelation and that of the true gel time at a localized spot determined by the high-speed motion picture should be noted to avoid excess agitation, which can result in total collapse into gel fragments of the just solidifying or already solidified gel under strong deformational influence by mechanical agitation, for example.

Soft Ionic Diode Fabricated Using Asymmetric Ion Distribution in Li+-Zn(II)/Cu(II) Metallohydrogels.

The development of metal ions-incorporated soft materials is of great importance in the present scenario due to their essential requirement in the fabrication of the components such as ionic diodes and electrochemical transistors for soft electronic devices. In the current work, to fabricate a soft ionic diode, two distinct Li+-driven conductive metallohydrogels, namely, MG-Zn and MG-Cu, have been obtained by individually treating a LiOH deprotonated pregelator (H5APL) with Zn(OAc)2 or Cu(OAc)2. The pregelator and metallohydrogels have been well characterized by using various instrumental techniques, which supports their proposed formulations. Field emission scanning electron microscopic images of metallohydrogels reveal the presence of a fibrous network, which helps to create a gel matrix, whereas the rheological experimental results ascertain the true gel phase nature of the synthesized metallohydrogels. The obtained MG-Zn and MG-Cu metallohydrogels were subjected to electrochemical impedance spectroscopic and band gap measurements. The MG-Zn and MG-Cu showed ionic conductivities of 1.02 × 10-3 and 1.14 × 10-3 S/cm, along with band gaps of 2.82 and 2.85 eV, respectively, thus claiming their suitability for device fabrication. Further, the fabricated metallohydrogel-based ionic diode shows appreciable ability to rectify the ionic current with the forward and reverse bias currents of 19 and 1.9 mA at +/-4 V bias potential. Based on all the experimental results, the mechanism has been well established for the rectification behavior in the fabricated metallohydrogel ionic diode.

Physicochemical, Morphological, Thermal, and Rheological Properties of Native Starches Isolated from Four Cultivars of Anchote (Coccinia abyssinica (Lam.) Cogn.) Tuber.

Anchote (Coccinia abyssinica (Lam.) Cogn) is a potentially important source of starch and an underutilized root and tuber crop indigenous to Ethiopia. In this study, the physicochemical, morphological, thermal, and rheological properties of native starches isolated from four cultivars of anchote tubers were studied and compared to potato and cassava starches, which were considered as references. The amylose content of anchote starches varied from 15.8–22.3%. The anchote cultivars showed different granule sizes, but all revealed a B-type crystalline structure, identical to potato starch. The phosphorus content of anchote starches ranged from 82–93 mg/100 g and was much higher than that of potato and cassava (60.3 and 5.8 mg/100 g, respectively). This characteristic could govern several functional properties of anchote starches, making them suitable for applications in different types of noodles, glucose syrups, and viscous products. The gelatinization temperature and enthalpy of anchote starches, which ranged from 60.97 °C to 69.33 °C and 16.87 to 18.38 J/g, respectively, were considerably different compared to potato and cassava starches. Significant variations were also observed among the pasting properties of starches from anchote cultivars. They showed a higher stability to heating and shearing, having higher TV (2046 to 2280 mPa·s) and lower BV (248 to 487 mPa·s) values, and a higher final viscosity (3409 to 3686 mPa·s) than potato and cassava, which are important characteristics in food processing and when high gel viscosity is required after cooling. Anchote starch gels exhibited rheological characteristics of true gels, showing much lower (tan δ)1 values and significantly higher viscoelastic moduli than those found in cassava and potato gels. The present study revealed significant differences among the physicochemical properties of anchote starches, depending on the cultivar, and demonstrated their promising potential in food product development and other industrial applications.

Gelation mechanisms of granular and non-granular starches with variations in molecular structures

Gelation is a critical functional property that determines the applications of starch. This study aimed to elucidate the gelation mechanisms of granular and non-granular starches varying in molecular structures. Five representative starches – including waxy maize (containing 1.9% amylose), normal maize (32.0% amylose), tapioca (29.1% amylose), pea (39.2% amylose), and high-amylose maize (HA7; 69.7% amylose) – were pasted in both physical forms at 95 °C with 8.0% concentration (w/w, dry basis) to examine the gelation behaviors. The gelation process of cooling (2 °C/min) and 2-h curing at 25 °C was monitored using dynamic rheological tests. The derived starch gels/pastes were further characterized using uniaxial compression test and scanning electron microscopy (SEM). The granular starches showed gelling ability in an order of pea > normal maize > HA7 > tapioca, waxy maize. For native, granular starches, the existence of swollen starch granules/remnants that were able to deform with each other to fill the whole volume of a mold was crucial for developing a strong, true gel; additionally, amylose molecules diffusing out from granules could act as a glue to further enhance the firmness of gel network, such as in pea starch gel. After the granular structure was destroyed, only non-granular HA7 – having linear amylose as the predominant component – could generate a firm and rigid gel, resulting from the re-association and alignment of amylose chains to establish stable junction zones. This study provided fundamental knowledge for using starch of various physical states as a gelling agent to achieve desirable textural attributes of foods and other industrial products.

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.

A luminescent lyotropic liquid-crystalline gel of a water-soluble Ir(III) complex

In the present study, the synthesis and properties of a novel water soluble Ir(III) complex of formula [(ppy)2Ir(dpq)]CH3CO2 is described, where ppy is the cyclometalated 2-phenylpyridine ligand and dpq the dipyrido[3,2-f:2′,3′-h]quinoxaline used as ancillary ligand. Own to its specific molecular structure, this complex forms highly ordered supramolecular gels in water on a wide range of concentration, from 3 to 14% w/w. The gel phase shows birefringence under cross polarisers that is completely loss when water is removed, evidence of the formation of a true lyotropic liquid-crystalline gel, without the need of an additional gelator. The gel is macroscopically formed of entangled microfibers that can be seen under optical microscope and that display luminescent properties as observed by confocal microscopy. X-Ray diffraction allowed to resolve the structure of the lyotropic mesophase that is formed by columns of complex cations organised in a tetrahedral manner which are in turn arranged in a larger oblique lattice, hence showing a high degree of order. The photophysical properties of the complex in its different state of matter (solid, gel phase and xerogel) are presented and discussed.

Biocompatibility and selective antibacterial activity of a bismuth phosphinato-nanocellulose hydrogel

Antimicrobial hydrogels are of immense value in wound care applications. However, the rapid rise of antimicrobial resistance has made it necessary to look for new antimicrobial additives for such materials. In this study, a novel antimicrobial hydrogel for wound care applications has been developed. The material combines TEMPO-oxidized nanocellulose hydrogel with a new class of antimicrobial agent, phenyl bis-phosphinato bismuth (III) complex. The hydrogel was characterized using scanning electron microscope imaging to show the overall distribution of the complex particles within the nanocellulose hydrogel matrix phase. The rheological properties of the bismuth loaded hydrogel are comparable to commercial over-the-counter burn hydrogels and behave like true gels. Activity of the different concentrations of the complex was studied against a range of medically important bacteria and mammalian fibroblast cells. Bismuth complex target loading of 9 µg/g showed bactericidal activity against Acinetobacter baumannii and Pseudomonas aeruginosa and bacteriostatic effect against MRSA and VRE, while having no toxic effect on mammalian fibroblast cells. However, Escherichia coli was less susceptible to this concentration comparatively. Our study has identified a range of bismuth complex loading levels for the material at which the additive appears to be safe and active. This study is a step towards the design of a biocompatible and renewable hydrogel containing a safe antimicrobial additive, which has an excellent safety margin to pathogenic bacteria over mammalian cells and would appear to be a promising material for active wound dressing applications.

Cellulose Nanofibrils/Xyloglucan Bio-Based Aerogels with Shape Recovery.

Bio-based aerogels containing cellulose nanofibrils (CNFs) are promising materials due to the inherent physical properties of CNF. The high affinity of cellulose to plant hemicelluloses (xyloglucan, xylan, pectin) is also an opportunity to develop biomaterials with new properties. Here, we prepared aerogels from gelled dispersions of CNFs and xyloglucan (XG) at different ratios by using a freeze-casting procedure in unidirectional (UD) and non-directional (ND) manners. As showed by rheology analysis, CNF and CNF/XG dispersions behave as true gels. We investigated the impact of the freezing procedure and the gel’s composition on the microstructure and the water absorption properties. The introduction of XG greatly affects the microstructure of the aerogel from lamellar to cellular morphology. Bio-based aerogels showed high water absorption capacity with shape recovery after compression. The relation between morphology and aerogel compositions is discussed.

Rheological characterisation of yolk‐based gels and Staphylococcus growth

SummaryModel yolk‐based (10% v/v) gels with different concentrations of κ‐carrageenan (0–2% w/w) were characterised employing rheological measurements, textural analysis and scanning electron microscopy. Additionally, the effect of the microstructure of the model gels on the growth rate of Staphylococcus was also evaluated. In all cases, the nature of the gel was dominated by the elastic component, specifically, 1.5, 1.75 and 2% κ‐carrageenan samples can be described as ‘true gels’ (tan δ < 0.1). Maximum strength of the interactions between rheological units (A) was observed with 1.75% κ‐carrageenan (4.74 ± 0.38 kPa), which indicates that the strength of interactions was determined not only by κ‐carrageenan concentration, but also by the amount of yolk. Finally, an inverse linear correlation was found between the maximum specific growth rate of Staphylococcus and rheological data (R2 > 0.99).

Changes in thermoviscoelastic and biochemical properties of Atroncau blancu and roxu Afuega'l Pitu cheese (PDO) during ripening

Thermoviscoelastic and biochemical properties of Afuega'l Pitu cheese blancu (B) and roxu (R), a Spanish acid-curd cheese made from cow’s milk, were determined at 3, 15, 30 and 60 days of ripening. The contents of fat (>45 g/100 g total solids, TS) and NaCl (<3 g/100 g TS) were similar between varieties and did not change with ripening. Total solids, pH, nitrogen fractions and fat acidity increased with ripening time in B and R samples. Lactose content was higher in B than in R cheeses at 3 d, was degraded gradually throughout ripening but did not disappear totally in both cheeses at 60 d. Viscoelastic parameters were determined in the linear viscoelastic region (LVER) by stress sweeps (6.3 rad/s, 20 °C): the stress amplitude (σmax) and complex modulus (G*) increased, while strain amplitude (γmax) decreased up to 60 d. Mechanical spectra were also determined, in the LVER, at 20 °C, 50 °C and 75 °C, showing that all samples behaved as “true gels” (elastic modulus, G' > viscous modulus, G''), irrespective of temperature. The best gel properties (low values of loss factor, tanδ = G''/G', and minor frequency dependence, i.e., low n', n'' exponents), were observed at 20 °C for B30 and R30. The viscoelastic parameters (G0' and G0'') increased with ripening time, irrespective of the temperature, and for a fixed ripening time they were lower at higher temperature. At 75 °C, all samples exhibited notable frequency dependence (n'' ≫ n'), resulting in shear-induced gelation at low frequencies (high oscillation times) which was consistent with data in thermal profiles from 70 °C to 90 °C.

Analysis of the Gel Point of Polymer Model Networks by Computer Simulations

The gel point of end-linked model networks is determined from computer simulation data. It is shown that the difference between the true gel point conversion, pc, and the ideal mean field prediction for the gel point, pc,id, is a function of the average number of cross-links per pervaded volume of a network strand, P, and thus, exhibits an explicit dependence on junction functionality, f. In contrast, the amount of intramolecular reactions at the gel point is independent of f in a first approximation and exhibits a different power-law dependence on the overlap number of elastic strands as compared to the gel point delay, pc – pc,id. Therefore, pc – pc,id cannot be predicted from intramolecular reactions and vice versa in contrast to a long standing proposal in the literature. Instead, the main contribution to pc – pc,id for P > 1 arises from the extra bonds needed to bridge the gaps between giant molecules separated in space and scales roughly ∝ (P – 1)−1/2. Further corrections to scaling are due to nonideal reaction kinetics, composition fluctuations, and incompletely screened excluded volume, which are discussed briefly.

Colloidal Behavior of Cellulose Nanocrystals Grafted with Poly(2-alkyl-2-oxazoline)s.

Polymer grafting onto cellulose nanocrystals (CNCs) has been used as a tool to improve CNC dispersion in nonpolar solvents or polymeric matrixes. The grafting of flexible polymer chains onto rigid particle surfaces leads to significant modifications in colloidal behavior. Here, poly(2-alkyl-2-oxazoline)s of well-defined molar mass and narrow molar mass distribution were synthesized by cationic ring-opening polymerization and grafted onto CNC surfaces, where the coupling reaction was favored when partially hydrolyzed polymers were used (reaching 64% reaction yield). The particles grafted with polymer chains could be redispersed in water after freeze-drying, producing stable dispersions, and they were not cell-toxic up to 10 wt % aqueous dispersion. Colloidal stability, nanostructure organization, and rheological behavior of grafted CNC and CNC-grafted CNC mixtures were evaluated. The rheological behavior of grafted nanoparticles, meanwhile, showed new features when compared to original CNC dispersions. Aqueous CNC dispersions showed a liquid crystal nematic organization and rheological behavior characteristic of true gel (at 5 wt %) prior to drying. On the other hand, nanoparticle dispersions behaved as weak gels upon the addition of 10 wt % of CNC-g-(PEtOx95-s-Ei5) under the same conditions. Dispersions of CNC-g-P(PEtOx-s-Ei) particles obtained by redispersion of freeze-dried particles behaved as a fluid, without the presence of the nematic organization. Through oscillatory rheology and time-domain NMR results, it can be concluded that polymer–water interactions are dominant over CNC–water interactions, being responsible for CNC nematic phase disruption. By introducing polymer chains, the introduction of isotropic character modifies water organization, changing the flow behavior of CNC-grafted with poly(oxazoline)s.

Thermo‐Rheology of a Proline‐Based Surface‐Active Ionic Liquid: Mixtures with Water and n‐Octane

AbstractSurfactant flooding is one of the most promising techniques to recover oil from unprofitable reservoirs. Surface‐active ionic liquids can overcome the limitations of the current surfactants. The rheology of the injecting solutions and the formed slugs is critical in the evaluation of an enhanced oil recovery process. The thermo‐rheological behavior of a biodegradable surface‐active ionic liquid, [ProC4]DS, and the corresponding binary and ternary mixtures with water and n‐octane was studied. All flow curves exhibited shear‐thinning and thixotropic behavior. The viscoelastic behavior of the ternary samples depended strongly on the [ProC4]DS content. Three different regions were identified: typical liquid‐like behavior, weak gel, and true gel. The thermal profiles indicated that the tested systems were fully thermoreversible.

Gelling pectins from carrot leftovers extracted by industrial-enzymes with ultrasound pretreatment

Misshapen carrots were upgraded as orange-colored pectin-enriched fractions (PEFs) useful as gelling agents and containing α- and β-carotenes, lutein, and α-tocopherol, by applying a green process consisting of an ultrasound (US) pretreatment (12.27 W/cm2 power intensity) followed by stirring in citrate buffer (pH 5.20) either without or with an industrial enzyme (fungal and bacterial hemicellulases, and cellulase) commercialized as baking improvers. PEFs showed uronic acid (UA) contents between 39 and 51% with low degree of methylesterification (DM, 37.2–48%), 11–22% degree of acetylation (DA), and a common molecular weight of 121,000–138,000 Da. The protein contents were 9.6–17.8%. Only the use of fungal hemicellulase produced per se higher yield of the PEF obtained (10.4%), in comparison to the non-US pretreated citrate buffer extracted pectins (6.9%). The US-pretreatment was the step that decisively produced high extractive yields (≈20%), while there was not additional contribution of industrial enzymes. However, enzymes permitted to obtain PEFs with different gel characteristics. US-pretreated PEFs at 2.00% w/v in water showed the best rheological performances, forming calcium-crosslinked true gels, more structured and with higher elastic (G’) modulus than non-US pretreated isolated fractions, one of which did not gel, being then useful as functional additives for food formulation.

Antioxidant pectin enriched fractions obtained from discarded carrots (Daucus carota L.) by ultrasound-enzyme assisted extraction

Carrot residues were upgraded as pectin-enriched fractions (PEFs) useful for functional food formulation due to co-extracted antioxidants (α- and β-carotenes, lutein, α-tocopherol), and gelling effect. High power ultrasound (US)-enzyme assisted extraction was applied for efficiency and sustainability. Carrot powder (CP) in citrate-buffer (pH 5.20) was submitted to US-pretreatment (12.27 W/cm2: 20 kHz, 80% amplitude, 20 min) and a subsequent digestion (5 h-40 °C) without or with hemicellulase or cellulase. US-hemicellulase led to the highest PEF yield (27.1%), and extracted almost the whole pectin content of CP. US-pretreatment increased the extraction yield of all PEFs, but the existence of an additional positive effect of the following step depended on the enzyme used. PEFs contained 40–47% of UA with low DM (24–49.9%), and co-extracted antioxidants. US decreased the antioxidant contents, DM, and molecular weight, but allowed obtaining calcium crosslinked true gels, also with higher elastic modulus than non-US-extracted PEFs, being promising as food additives.

High-dose coenzyme Q10-loaded oleogels for oral therapeutic supplementation

Coenzyme Q10 (CoQ10) is a mitochondrial respiratory cofactor and potent endogenous antioxidant. In CoQ10-deficient patients, early treatment with high-oral doses (5–50 mg/kg/day) can limit the progression of renal disease and the onset of neurological manifestations. Crystalline CoQ10 is lipophilic, water-insoluble, and poorly absorbed in the gut. Here, CoQ10 showed low bulk density, another important disadvantage in solid oral formulations. Thus, we propose the use of oleogels to maintain dissolved a high-dose of CoQ10 in medium-chain triglyceride (MCT) oil, using ethylcellulose (EC) for gelling, and a surfactant (sorbitan monostearate –SMS- or lecithin). “True gels” were only obtained with the surfactant presence. Thermoreversible oleogels with 1 g of dissolved CoQ10 per 5 g-disk were successfully developed with proved stability and solubility for 12 months (25.0 °C). SMS was better than lecithin as a surfactant because it allowed lower syneresis, higher CoQ10 retention for 12 months, and notably higher oxidative-stability of the MCT-oil, best immobilized by its true gel network. Plastic deformation without fracture was determined under compression, emulating the soft deformation behavior inside the mouth. SMS-oleogels allowed loading a maximal solubilized CoQ10 dose with maximal stability, and may be easier to swallow by CoQ10-deficient patients who suffer from secondary dysphagia.

Role of the oil on glyceryl monostearate based oleogels

The high consumption of saturated and trans fats, used in the formulation of lipid-based foods, is associated with incidence of health problems. Organogels or oleogels are a novel class of structured lipids formed from liquid oil as continuous phase entrapped within network of structuring molecules. The aim of this study was to understand the role of oils with different composition on the formation of glyceryl monostearate (GM) gel network. Glyceryl monostearate-based oleogels were produced with the minimal concentration of 5 wt% in sunflower (SF), high oleic sunflower oil (HOS) and coconut oil (CO). The influence of the oil type on the physicochemical properties of the gel was analyzed. The GM gels showed a solid-like behavior using either high oleic sunflower or sunflower oils but did not form a true gel with coconut oil. Although different oils could affect the crystal formation, all gels exhibited needle-like crystal morphology regardless solvent quality. The GM crystals arranged in a lamellar configuration are responsible for entrapping both SF and HOS oils. Degree of saturation of oils might affect GM oleogel properties. Long chain monounsaturated fatty acids favored the packing of GM crystals in a cohesive gel. Furthermore polymorphism with preferential crystalline β’ form of GM was formed using a medium containing one and two unsaturation. In conclusion, it was observed that the type of oil influenced the formation of the GM gel network. These findings allow the better understanding of GM-based oleogels, providing opportunity to design for food products with improved technological and nutritional properties.

Using Aggregation-Induced Emission to Understand Dipeptide Gels.

We describe the formation of structured liquids and gels from a functionalised dipeptide based on tetraphenylethylene. Tetraphenylethylene is well-known to be able to undergo aggregation-induced emission. We use the emission data to understand the behaviour of the dipeptide in water under a variety of conditions. The dipeptide forms viscous solutions at high pH. Gels can be formed by a pH-trigger, but syneresis occurs. Addition of a calcium salt also leads to a gel with slight syneresis. Addition of sodium chloride leads to a self-supporting material, but this is not a true gel from the rheological perspective. From the emission data, we infer that there are limited structural changes on addition of sodium chloride or acid, but there are significant changes in molecular packing when the gel is formed by addition of a calcium salt.