Crystal Network Structure Research Articles

Development and characterisation of a novel bigel based on pea protein hydrogel and rice bran wax oleogel: Enhancement of rheological properties and freeze-thaw stability

In this study, a novel pea protein (PP)-based bigel was developed, featuring a high internal phase emulsion. The impact of gelling agent concentration on the gel properties and freeze-thaw stability of the bigel was investigated. The bigel was comprised of two distinct gel phases: an aqueous-phase gel with a covalent network formed by PP and transglutaminase (TGase), and an oil-phase gel with a crystal network structure of rice bran wax (RBW). Microstructural analysis revealed a bi-continuous network structure in the bigel, with network density increasing as TGase and RBW concentrations rose. Rheological analysis showed that storage modulus (G′), apparent viscosity, and structural recovery of the bigel increased with higher TGase and RBW concentrations. Temperature scanning experiments confirmed that the bigel maintained its elastic solid behavior even at elevated temperatures. Optimal sensory properties and low coefficient of friction were achieved at 0.4 % TGase and 7 % RBW concentrations. Additionally, the bigel exhibited notable freeze-thaw stability at TGase and RBW concentrations exceeding 0.2 % and 5 %, respectively. These findings highlight the excellent gelation properties and stability of the PP-RBW-based bigel, suggesting its potential as a fat substitute in the food industry.

The beeswax-based fish oil oleogels adjusting the stabilization mechanism and lipid digestion of bi-layer emulsions: Spatial conformation and molecular interaction

Fish oil contains omega-3 polyunsaturated fatty acids, but their poor oxidation stability and gastrointestinal digestion rate led to the low bioavailability. Oleogels could improve the stability of EPA and DHA, so the effect of beeswax (BW)-based fish oil oleogels (FOGs) on the stabilization mechanism and lipid digestion of bi-layer emulsions was investigated. The results showed that the enhanced BW crystals lowered the myofibrillar protein (MP) unfolding along with the decrease in β-sheets, hydrophobic force and disulfide bond, thus reducing the interfacial adsorption capacity and emulsion stability. The enhanced BW formed the rigid crystal network structure and improved the crystal size in the inner layer. The suitable FOG addition (4 wt%) enhanced the unfolding of advanced structures in the outer layer, and the exposure of more hydrophobic groups and disulfide bonds facilitated the interfacial adsorption, thus reducing the size. The final release rate of FFAs significantly decreased with the increasing BW, and significantly increased and decreased with the increasing FOG. BW and FOGs could induce the changes in spatial conformation, and the exposure of hydrophobic groups and disulfide bonds affected the lipase contact at the interface. BW and FOG could adjust the crystal network structure in the inner layer and spatial conformation in the outer layer, thus improving the stabilization and lipid digestion of bi-layer emulsions. This study can provide a theoretical basis for developing DHA and EPA food.

Application of soy protein isolate-naringenin complexes as fat replacers in low-fat cream: Based on protein conformational changes, aggregation states and interfacial adsorption behavior

In this study, changes in the structural and functional properties of soybean protein isolate (SPI)-naringenin (NG) complexes under different amounts of naringenin treatments were explored, elucidating the effect of the complexes as fat replacers at the 15 % substitution level on the properties of low-fat cream. Finally, the correlation between the structure and function of the complex and the properties of low-fat cream was further analyzed. The addition of NG promotes the increase of SPI aggregation and particle size, and reduces the interfacial tension of the complex. Meanwhile, at the mass ratio of 48:3, NG and SPI formed a dendritic network structure suitable for stabilizing cream. The fat properties of cream indicate that low-fat creams stabilized by appropriate proportions of SPI-NG complexes displayed small and dense fat crystal network structures. In addition, low-fat cream stabilized by the SPI-NG complexes have improved whipping time, overrun, firmness, storage stability and rheological properties compared to natural SPI. It is worth noting that the overall quality of the cream stabilized by the SPI-NG complex with a mass ratio of 48:3 was almost close to that of full-fat cream. Therefore, this study promotes the potential applications of protein-polyphenol complexes as fat replacers in the food industry.

Comparison of threshold algorithms for automatic processing of fat crystal microscopic images based on ImageJ

AbstractMicroscopic image analysis is a crucial tool in fat crystallization research, enabling the analysis of crystal size, network structure, fractal dimension and other parameters through binarization. It is essential to seek an appropriate thresholding algorithm to binarize fat crystal images, which plays a vital role in image segmentation. In this article, the effectiveness of 17 thresholding algorithms such as Default, Mean, IsoData, Otsu, Li and Triangle were analyzed in processing fat crystal images with different shapes, background colors and image intensities. This was expected to discover a stable and objective thresholding algorithm for the binarization of fat crystal images. The performance evaluation was conducted according to the peak signal noise ratio (PSNR), structural similarity index (SSIM) and region non‐uniformity (RNU) parameter. Moreover, the comparative analysis of crystal size error, crystal area fraction and intraclass correlation coefficients (ICC) for fractal dimension values would provide a foundation for the selection of thresholding techniques for fat crystal network images. The results indicated that the Default algorithm exhibited remarkable robustness and applicability with high‐quality and stable outputs in fat crystal image processing.

The Impact of Oil Type on the Performance of β-Amyrin-Based Oleogels: Formation, Physicochemical Properties, and Potential Correlation Analysis.

Pentacyclic triterpenes show potential as oleogelators, but their combination with various vegetable oils has limited research. This study selected linseed, rapeseed, sunflower, coconut, and palm oils to combine with the triterpenoid compound β-amyrin for the preparation of oleogels. The stability, crystal network structure, and other properties of each oleogel were evaluated. The correlation between different oil types and the properties of corresponding oleogels was explored. The results showed that β-amyrin formed stable oleogels with five vegetable oils under suitable temperature conditions, wherein especially the LO-based oleogel not only exhibited higher oil-binding capacity and hardness, but also demonstrated excellent stability at the microscopic level and notable rheological properties. Further analysis revealed a close correlation between the physicochemical properties of the oleogels and lipid characteristics, indicating that oleogels prepared from long-chain highly unsaturated fatty acids exhibit high stability. The above results indicate that β-amyrin can be a novel candidate oleogelator and that the oil type can modify the properties of β-amyrin-based oleogels. This study provides the latest reference for the application of pentacyclic triterpenoids in food.

Fat coalescence and texture improvement of ice cream based on medium-chain triglyceride oleogel: Effect of gelator type

Academics and industry have invested in creating novel and functional ice creams to meet the growing demand for frozen foods that promote human health and nutrition. This study aimed to investigate the effect of medium-chain triglyceride (MCT) oleogels that prepared by three different gelators on the development of ice creams, as a complete substitute for hydrogenated palm kernel oil (HPKO). The results showed that both beeswax (BW) and phytosterol-oryzanol (PS-GO) caused the fat crystal to grow into three-dimensional spherulites, while ethylcellulose (EC) inhibited crystal size growth. Among the three types of oleogel-based ice creams, the BW sample exhibited the highest coalescence degree, followed by PS-GO and EC. The difference was due to variations in crystal growth and rigid crystal strength. Both BW and PS-GO oleogels improved the firmness of the ice creams by enhancing the formation of crystal network structures in the emulsions. The EC oleogel did not contribute to the overrun of the ice cream. The well-structured fat with partially coalesced aggregates can stabilize the bubbles and hold the aqueous phase of ice creams, preventing the outflow during meltdown. Oleogels that form crystal networks can be employed as a preferable replacement for HPKO in the production of ice cream with superior texture.

Effect of different chain lengths of monoglyceride on the O/W interfacial properties with high-melting and low-melting crystals in low-fat aerated emulsion.

The effect of different types of monoglycerides, including monopalmitin, capryl monoglyceride (GMB), and succinylated monoglyceride (GMSA) in combination with palm kernel stearin (PKS) and beeswax (BW), on the formation, crystal network structure, and partial coalescence properties of aerated emulsions (20% w/w fat) was investigated. The stability of BW and PKS crystals with a 1% concentration of GMSA and GMB, respectively, in the oil phase was lower than the other crystals. BW-GMSA and PKS-GMB crystals exhibited a lower crystallization rate, higher contact angles and no significant peak shift in the small-angle X-ray scattering results. The BW-GMSA and PKS-GMB emulsions had a lower nucleation rate in the bulk and a higher nucleation rate at the interface, resulting in a higher fraction of crystals adsorbed at the oil/water interface. This reduced the number of interfacial proteins and led to a high degree of partial coalescence and the formation of stable aerated networks.

A sight of self-assembly mechanism in fish oil oleogels: Phase transition, crystal structure and non-covalent interaction

Fish oils contain ω-3 polyunsaturated fatty acids (PUFAs), but easily cause quality deterioration due to the oxidation. Beeswax-based oleogels could wrap fish oils by beeswax self-assembly. The phase transition, crystal structure and non-covalent interaction were investigated to reveal the self-assembly mechanism from the perspective of beeswax and oil phase characteristics. The results indicated that high unsaturation degree, PUFAs and beeswax additions promoted phase transition, SFC and stable crystal networks. The changes of crystal structures were ascribed to the polymorphism and polymorphic transition. β-Polymorphs could form crystal networks, and β′-polymorphs could influence the size of crystal chains or clusters as well as crystalline domains. Crystalline domain sizes affected crystal morphologies and network structures, including plate-like structures and multi-layer porous structures. UFAs could involve the beeswax self-assembly to change structure characteristics by van der Waals forces and π-π stacking. The OBC remained 100%, when beeswax additions reached more than 6%. Hence, beeswax additions, PUFA contents and unsaturation degree all influenced the self-assembly mechanism and adjusted the macroscopic properties of oleogels.

Electrical dehydration performance of shale oil: From emulsification characteristics to dehydration mechanisms

Shale oil, as a successor to ordinary crude oil, has received extensive attention. However, the high-stability shale oil emulsions are still challenging for electrical dehydration systems. In this work, the differences between shale oil and ordinary crude oil were compared in terms of emulsion droplet size, physical properties and components to clarify the emulsification characteristics of shale oil and reveal its electrical dehydration mechanism. To this end, comprehensive electrical dehydration experiments were carried out under different parameters and transformers. The results showed droplet diameters of shale oil emulsions less than 10 µm, a value much smaller than that of crude oil. Shale oils with high viscous contained lots of natural emulsifiers, promoting the formation of the rigid asphalt film and wax crystal network structure. The synergistic adsorption of surfactant and paraffin molecules and the film formation of asphaltenes promoted by resins make shale oil display lower interfacial tension and higher interfacial film pressure. The above characteristics were the main reasons behind the formation of shale oil stable emulsions. Factors, such as electric field frequency, dehydration temperature, dehydration time, and demulsifier concentration influenced the emulsification characteristics and dehydration performance of shale oils at variable degrees. The dehydration performances of high-frequency transformer (Transformer B) and ultra-high-frequency transformer (Transformer C) on shale oil emulsion SH-1 were better than that of low-frequency transformer (Transformer A) due to tensile breakup or oscillatory coalescence of droplets under different electric field conditions. Considering energy consumption and economy comprehensively, Transformer C has excellent application potential. The analyses also show that high-frequency, heating and adding demulsifier are the key and necessary factors in the electric dewatering treatment of shale oil. In sum, these results look useful for future design optimization of shale electrical dehydration devices.

Study on the influence mechanism of the interaction between waxes and asphaltenes on hydrate growth

Waxes and asphaltenes, two typical heavy components of crude oil, can complicate hydrate problems associated with deep-sea multiphase transport. This study investigates the transformation of water droplets into hydrate particles in waxy and wax-asphaltene coexisting systems. The results indicate that dissolved wax molecules increase the porosity, degree of transformation, and surface roughness of hydrate particles. In addition, the size of hydrate particles increases over time. Besides, wax precipitation precedes hydrate formation as wax content increases. When the crystal network structure is formed, the viscosity of the continuous phase increases significantly, and the mass transfer process is severely impeded, thereby inhibiting the hydrate transformation process. Moreover, adding asphaltenes will influence adsorption at the oil–water interface and inhibit the effect of wax molecules on hydrate particles. The asphaltene concentration required to inhibit the effect of wax molecules is proportional to the wax concentration.

Crystallization and Structural Properties of Oleogel-Based Margarine.

Interest in oleogel as a promising alternative to traditional hydrogenated vegetable oil has increasingly grown in recent years due to its low content of saturated fatty acids and zero trans fatty acids. This study aimed to develop wax-based margarine to replace traditional commercial margarine. The wax-based margarine was prepared and compared with commercial margarine in texture, rheology, and microscopic morphology. The possibility of preparing margarine at room temperature (non-quenched) was also explored. The results showed that the hardness of oleogel-based margarine increased as the BW concentration increased. Denser droplets and crystal network structure were observed with the increase in BW content. XRD patterns of oleogel-based margarine with different content BW were quite similar and structurally to the β' form. However, the melting temperature of oleogel-based margarine was over 40 °C at each concentration, which represented a poor mouth-melting characteristic. In addition, the unique, improved physical properties of oleogel-based margarine were obtained with binary mixtures of China lacquer wax (ZLW) and Beeswax (BW), due to the interaction of the ZLW and BW crystal network. The rapid cooling process improved the spreadability of oleogel-based margarine. The margarine prepared by 5% BW50:ZLW50 had similar properties to commercial margarine in texture and melting characteristics (37 °C), which had the potential to replace commercial margarine.

Effect of molecular structure changes during starch gelatinization on its rheological and 3D printing properties

Although the changes in molecular structure during starch gelatinization has been intensively investigated, how a relationship between starch rheological properties, printability, and starch molecular structure changes during starch gelatinization remains unclear. This research is focused on the molecular structure changes of corn starch (CS) gels caused by different treatment temperatures and their effects on CS gel rheological and 3D printing properties. With increasing treatment temperature, the leached amylose content and short linear chains (DP 6–12) of CS increase, whereas the contents of long linear chains (DP > 12) decrease, which influences the rheological and 3D printing properties of starch. Due to the presence of the original granules and crystalline structure, the CS-65 starch gel presented a poor storage modulus (G′), indicating poor 3D printing performance. The leaching of amylose induced the formation of new crystal and cross-linked network structures, which is beneficial for increasing its G′. However, the increase in short amylopectin linear chains (DP 6–12) reduced the degree of short-range order and hydrogen bonding interactions, which was detrimental to its G′ and yield stress (τf). CS-80 starch gel exhibited the largest G′ and shear recovery rate, showing the highest self-supporting properties and printing precision. Extremely high temperatures contributed to the densification of the starch gel structure, which led to an increase in τf and difficult extrusion. Overall, molecular structural changes caused by starch gelatinization are critical to its ideal rheological properties for 3D printing.

Partial coalescence and whipping capabilities of dairy aerated emulsions as affected by inclusion of monoglycerides with different fatty acid species

Whipping capabilities are the most important indices of dairy aerated emulsions for their use in cakes, desserts and toppings. However, poor whipping capabilities may occur because of included soft fats. Monoglycerides, namely glyceryl monostearate (GMS), glycerol monooleate (GMO) and glycerin monolaurate (GMLa), are the suggested improvers in controlling whipping process through changing partial coalescence behaviours of fat globules. Effects of the three monoglycerides on two crucial whipping factors, that is, fat crystallisation and interfacial properties, were analysed in the present study. It is found that low levels of monoglycerides (<0.25%) showed little effects on the development of partial coalescence, while positive performance was observed in those formulated with increased concentrations ranging from 0.50 to 0.75%. In comparison with GMO, monoglycerides with saturated species significantly improved density and ordering of fat crystal networks and reduced interfacial protein concentrations, contributing to the development of partial coalescence and bubble structures during whipping. Rheology analyses further strongly supported that GMS and GMLa strengthened fat crystal network structure, thereby improving shaping property and heat resistance of foam. The results provided a theoretical basis for improving whipping capabilities of aerated emulsions.

From mesoscopic reconstruction to flexible meso-electronics based on nucleation control refolding rerouting of silk fibroin materials

Attributed to advanced structural characterization techniques, mesoscopic hierarchical structures as well as crystal network structures have been verified in both natural and artificial soft materials including silk fibroin materials. Notably, the close correlation between mesoscopic structures (especially the structure of crystallite and crystal network) and macroscopic properties suggests that the functionalization of SF materials could start from the mesoscopic structure reconstruction in a designed manner. This review gives an overview of recent SF materials with novel and enhanced properties which are achieved by meso doping as well as meso hybridization via directing the nucleation pathways and changing nucleation kinetics. Besides, the kinetic meso reconstruction factor λ is also put forward and emphasized to quantitatively describe the templating effects of specific templating seeds, irrespective of macromolecules or nano functional seeds. The as-acquired functionalized SF materials can be further applied to fabricate bio-compatible and degradable flexible/implantable meso electronic devices (e.g., E-skins and memristors), and applicable to on-skin long-term monitoring of human physiological conditions, in-body sensing, information processing and storage.

Synergistic effects of oleogelators in tailoring the properties of oleogels: A review

Conventional solid fats play a crucial role as an ingredient in many processed foods. However, these fats contain a high amount of saturated fats and trans fats. Legislations and dietary recommendations related to these two types of fats set forth as a consequence of evidence showing their deleterious health impact have triggered the attempts to find alternate tailor-made lipids for these solid fats. Oleogels is considered as a novel alternative, which has reduced saturated fat and no trans fat content. In addition to mimicking the distinctive characteristics of solid fats, oleogels can be developed to contain a high amount of polyunsaturated fatty acids and used to deliver bioactives. Although there has been a dramatic rise in the interest in developing oleogels for food applications over the past decade, none of them has been commercially used in foods so far due to the deficiency in their crystal network structure, particularly in monocomponent gels. Very recently, there is a surge in the interest in using of combination of gelators due to the synergistic effects that aid in overcoming the drawbacks in monocomponent gels. However, currently, there is no comprehensive insight into synergism among oleogelators reported in recent studies. Therefore, a comprehensive intuition into the findings reported on synergism is crucial to fill this gap. The objective of this review is to give a comprehensive insight into synergism among gelators based on recent literature. This paper also identifies the future research propositions towards developing oleogels capable of exactly mimicking the properties of conventional solid fats to bridge the gap between laboratory research and the food industry.

Structuring of Edible Liquid Oil into Smart Thermo-Triggered Soft Matters for Controlled Bioactive Delivery.

Growing interest is being dedicated to smart soft matters because of their potential in controlling bioactives upon exposure to an appropriate stimulus. Herein, structuring of edible liquid oil into oleogels and emulgels as smart thermo-triggered soft vehicles for controllable release of diverse nutrients was developed. Edible liquid oil was trapped inside the crystal network structure of phytosterols and monoglycerides resulting in bicomponent solidlike oleogels. Subsequently, both water-in-oleogel (W/O) emulgels and glycerol-in-oleogel (G/O) emulgels were further fabricated by spatial distribution of the stabilizing interfacial crystals around dispersed droplets as well as the network crystals in the continuous phase. Rheological measurements showed that the gel strength of the oleogel-based emulgels depends on the fraction of the aqueous phase and is greater than that of corresponding oleogels due to a filler effect of dispersed aqueous droplets within the crystal network, offering an additional strategy to tune the structure and rheology. Comparatively, introducing glycerol endowed a higher gel strength for the oleogel-based emulgels than water, particularly at increased filler loads. In addition, these soft matters exhibited interesting thermoresponsive nature, which exhibit the flexibility for programmed release of coencapsulated bioactive components upon exposure to an appropriate thermal triggered switchable. The resulted smart thermo-triggered soft matters have emerging opportunities for application in functional active ingredient delivery by on-demand strategies.

Crystal network structure and stability of beeswax-based oleogels with different polyunsaturated fatty acid oils

The effect of different types of oils including camellia oil (CLO), sunflower oil (SFO), corn oil (CO) and linseed oil (LO) on the formation, crystal network structure and mechanical properties of 4%wt beeswax (BW) in oleogel was investigated. BW oleogels containing oils with higher contents of polyunsaturated fatty acids gelled first (1%wt), especially LO with higher contents of linolenic acid rather than CLO with higher contents of monounsaturated fatty acids. In comparison, oils with higher polyunsaturated fatty acid contents exhibited higher Db with more extensive microstructure at different cooling rates, which was related to shorter nucleation induction time of crystal and higher crystallinity. Stronger van der Waals forces were observed in oleogels with higher polyunsaturated fatty acid contents especially for LO oleogel. Rheology also showed that LO oleogel with higher content of linolenic acid had higher crystallinity and lower crystal melting interfacial tension, resulting in the formation of a more stable network structure.

Super enhancement of rheological properties of amorphous PLA through generation of a fiberlike oriented crystal network

Blends containing 85 wt. % of an amorphous polylactide with 15 wt. % of three different semicrystalline PLA (cPLA) grades with different crystallizabilty were separately blended via a twin-screw extruder below the melting temperature of the cPLAs. The extrudates were either directly pelletized or pelletized after being drawn at a draw ratio of 10. The small amplitude oscillatory shear behavior of the samples revealed that while the rheological properties of the undrawn samples were enhanced, those of the drawn samples were much more dramatically increased. In undrawn samples, the enhancements were due to the presence of unmelted crystal clusters, which could form a solid network structure in the blend. The much more pronounced increases in drawn samples, however, were due to the transformation of the crystal clusters into the fiberlike oriented crystal network, which formed a stronger solid network. This reinforcing behavior in both undrawn and drawn samples was even more pronounced when cPLA with a higher degree of crystallinity and a higher melting temperature was used. In drawn samples, the stress growth experiments confirmed the formation of such oriented crystal structure during which the primary overshoot caused by the crystal network structure could be formed again after molecular relaxation. This was while, in undrawn samples, stress overshoots were barely visible.

Effects of CaO and MgO contents on the properties of lightweight aggregate produced from municipal solid wastes

Sewage sludge (SS) and river sediment (RS) could be used as the raw material for the production of lightweight aggregate (LWA). CaO and MgO are present as the major inorganic oxides in SS and RS, little is known about their influences on the performance of LWA. This study aims to explore the effects of CaO and MgO contents on the properties of LWA. The results indicated that LWA with desired physicochemical quality were obtained with a CaO content range of 3–4% and a MgO range of 2–3%. Anorthite (CaAl2Si2O8), spinel (MgAl2O4) and enstatite (Mg2Si2O6) detected in crystal phase were conducive to enhancing the hardness of LWA. The presences of Ca2+ and Mg2+ contributed to stabilizing the crystal network structure and improving the strength of lightweight aggregate. Nevertheless, excess amount of CaO and MgO, which functioned as crystal network-modifier, were unfavorable to the production of high-strength lightweight aggregate.

Preshearing is an in situ setting modification method for inorganic bone cements

AbstractThe flow behaviour and injectability of calcium phosphate cements are outcomes of the complex interplay between time‐dependent processes of dissolution, nucleation and crystal growth. Their dependence on shear strains, frequencies and rates has been revealed by rheological investigation of the setting processes of a brushite cement under torsional flow. Various oscillatory torsional strain amplitudes and frequencies were seen to promote dissolution or delay crystal intergrowth compared to quiescently set cement samples. Oscillatory torsional strain amplitudes higher than the linear viscoelastic strain limit resulted in a pronounced lag in crystal intergrowth. Dissolution was enhanced and setting was promoted with increasing frequency and strain amplitude within the linear viscoelastic strain range. Changing the preshearing mode to steady torsion increased energy spent to microstructural deformation, counteracting the beneficial vibratory effect on cement setting kinetics, and produced a net retardation by the disruption of the crystal network structure. Such deformation history can be created in the cement suspension prior to injection during clinical practice by precise adjustment of the preshearing modes and parameters to enable the orthopaedic surgeon tailor the setting time, flow behaviour and injectability of calcium phosphate cements in situ without altering the cement chemistry, hence bioactivity.