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Hypothesis: Elucidation of the micro-mechanisms of sol-gel transition of gelling glucans with different glycosidic linkages is crucial for understanding their structure-property relationship and for various applications. Glucans with distinct molecular chain structures exhibit unique gelation behaviors. The disparate gelation phenomena observed in two methylated glucans, methylated (1,3)-β-d-glucan of curdlan (MECD) and methylated (1,4)-β-d-glucan of cellulose (MC), notwithstanding their equivalent degrees of substitution, are intricately linked to their unique molecular architectures and interactions between glucan and water., Experiments: Density functional theory and molecular dynamics simulations focused on the electronic property distinctions between MECD and MC, alongside conformational variations during thermal gelation. Inline attenuated total reflection Fourier transform infrared spectroscopy tracked secondary structure alterations in MECD and MC. To corroborate the simulation results, additional analyses including circular dichroism, rheology, and micro-differential scanning calorimetry were performed., Findings: Despite having similar thermally induced gel networks, MECD and MC display distinct physical gelation patterns and molecular-level conformational changes during gelation. The network of MC gel was formed via a "coil-to-ring" transition, followed by ring stacking. In contrast, the MECD gel comprised compact irregular helices accompanied by notable volume shrinkage. These variations in gelation behavior are ascribed to heightened hydrophobic interactions and diminished hydrogen bonding in both systems upon heating, resulting in gelation. These findings provide valuable insights into the microstructural changes during gelation and the thermo-gelation mechanisms of structurally similar polysaccharides., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Whey protein emulsion gel is an ideal model food for revealing how the multilength scale food structures affect food digestion, as their structure and mechanical properties can be precisely manipulated by controlling the type and intensity of intermolecular interactions between protein molecules. However, there are still significant understanding gaps among intermolecular interactions, protein aggregation and gelation, emulsion gel formation, gel breakdown in the gastrointestinal tract (GIT), and the practical use of whey protein emulsion gels, which limits their GIT-targeted applications. In this regard, the relationship between the structure and digestion behavior of heat-set whey protein emulsion gels is reviewed and discussed mainly from the following aspects: (1) structural characteristics of whey protein molecules; (2) how different types of intermolecular interactions influence heat-induced aggregation and gelation of whey protein in the aqueous solutions and the oil-in-water emulsions, and the mechanical properties of the final gels; (3) functions of the mouth, the stomach, and the small intestine in processing of solid foods, and how different types of intermolecular interactions influence the breakdown properties of heat-set whey protein emulsion gels in GIT (i.e., their respective role in controlling gel digestion). Finally, the implications of knowledge derived from the formation and gastrointestinal breakdown of heat-set whey protein emulsion gels for developing controlled delivery vehicles, human satiety enhancers, and sensory modifiers are highlighted., (© 2024 Institute of Food Technologists®.)

The serendipitous occurrence of gels in science has been a milestone for further industrial revolutionization. The controlled formation and disassembly of gels coupled with their viscoelastic properties and their ability to undergo extensive structural modification to suit different applications have led to the widespread use of gelation technology in different domains of science such as sensing, material chemistry and physics, medicine, food and nutrition, ecology, and more. With the rising interest in gelators and gels applications, accurately depicting the current status of gelation and associated technology is of paramount importance for researchers and scholars already immersed in gel technology as well as those aiming to delve into this field. Utilizing bibliometrics offers a systematic approach to analyze trends, citation patterns, and the impact of research, providing crucial insights for advancing knowledge and innovation in gel technology. By performing a comprehensive bibliometric analysis of scientific publications, using Vosviewer, Citespace, and Biblioshiny, in terms of co-authorship and co-citations of publications, and also the co-occurrence analysis of countries, institutions, authors, and keywords Research frontiers and hotspots in gelation and associated technologies in 21st century can be assessed. The result indicated a research frontier in the discipline of ecology, earth, and marine for gelator application and current hotspots within the research field of gelation technology in; catalysis, eutectogels development as an alternative for ionic liquid gels, gelators in drug delivery for antibacterial activity, oleogels in the food industry, low molecular weight hydrogels for tissue repair and 4D printing and gelators application for oil spill remediation and dye removal. This work, although not assessing fully the qualitative aspect of a research field, gives a broad quantitative analysis and direction of research within a research field. The result of this work will provide a comprehensive overview of the evolution of research in the field of gelation technology and a global understanding of research frontiers, hotspots, and drawbacks within the field to researchers and scholars willing to work in this research area., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study investigated the effect of gellan gum (GG) and glucono-δ-lactone (GDL) on the acid-induced gel properties of pea protein isolate (PPI) pretreated with media milling. The inclusion of GG substantially enhanced the gel hardness of PPI gel from 18.69 g to 792.47 g though slightly reduced its water holding capacity (WHC). Rheological analysis showed that GG increased storage modulus (G') and decreased damping factor of gels in the small amplitude oscillatory shear region and transformed its strain thinning behavior into weak strain overshoot behavior in the large amplitude oscillatory shear region. SEM revealed that GG transformed the microstructure of gel from a uniform particle aggregate structure to a chain-like architecture composed of filaments with small protein particles attached. Turbidity and zeta potential analysis showed that GG promoted the transformation of PPI from a soluble polymer system to an insoluble coagulant during acidification. When GG content was relatively high (0.2 %-0.3 %), high GDL content increased the electrostatic interaction between PPI and GG molecules, causing their rapid aggregation into a dense irregular aggregate structure, further enhancing gel strength and WHC. Overall, GG and GDL can offer the opportunity to modulate the microstructure and gel properties of acid-induced PPI gels, presenting potential for diversifying food gel design strategies through PPI-GG hybrid systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Co-amorphous (CM) is a promising technology for enhancing the aqueous solubility of insoluble drugs, but the gelation phenomenon has often occurred during the dissolution process and seriously threatened their solubility/dissolution performance. Therefore, it's quite important to design favorable CM systems to alleviate or even avoid the adverse effects of gelation phenomenon. In this study, CM systems of taxifolin (TAX) and oxymatrine (OMT) (TAX-OMT CMs) were constructed to improve the solubility and dissolution properties of TAX. Interestingly, TAX-OMT CMs gradually aggregated and obviously gelled during dissolution, but the solubility and dissolution of TAX in TAX-OMT CMs were significantly enhanced compared to crystalline TAX. Consequently, the underlying solubilization mechanisms of TAX-OMT CMs after gelation were systematically explored. For one thing, the complexation between the two components in TAX-OMT CMs was verified by phase solubility, fluorescence spectroscopy and isothermal titration calorimetry. For another, the residual solids of TAX-OMT CMs after dissolution evaluation were thoroughly characterized by means of powder X-ray diffraction, fourier transform infrared spectroscopy, scanning electron microscopy, which showed the anti-crystallization property of TAX-OMT CMs. Furthermore, molecular simulation demonstrated the intermolecular interactions of TAX-OMT CMs alone and TAX-OMT complexes in aqueous solution. Finally, pharmacokinetics study in rats suggested that the bioavailability of TAX in TAX-OMT CM (1:2) was approximately 5.5-fold higher than that of crystalline TAX after oral administration. Collectively, this study reveals the importance of complexation and anti-crystallization effects of CM systems on maintaining solubilization behavior after gelation, providing an effective strategy to improve the absorption performance of pharmaceutical CM systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The structure and functional properties of protein fibrils are closely related to environmental factors in fibrillation. Herein, soy protein isolate fibrils (SPIFs, 22 mg/mL) were prepared under acid-heating conditions in the presence of 100 mM metal ions (K + , Na + , Ca 2+ , Mg 2+ , and Fe 3+ ). Except for Fe 3+ , fibrillation and subsequent larger fibril aggregates were promoted, ultimately leading to gel formation. Compared with K + or Na + , the addition of Ca 2+ or Mg 2+ resulted in more organized SPIF structures with increased β-sheet contents and higher ThT fluorescence intensities. Furthermore, both of them resulted in longer fibrils with an average contour length of 700-800 nm, which significantly enhanced the storage modulus. However, the presence of Fe 3+ accelerated protein hydrolysis and inhibited SPIF formation, resulting in samples consistently exhibited liquid behavior. These findings provide a foundation for understanding the influence of metal ions on regulating the fibrillation and gelling properties of SPIFs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study examined multi-scale structural alterations of maize starches varying in amylose content during pasting and gelation, using Rapid Visco Analyser (RVA). At 50 °C, starch granules maintained their morphology with low viscosity. As the temperature increased to 95 °C, helical and crystal structures were destroyed, leading to granule swelling, distortion and porosity, as identified by Wide Angle X-ray Scattering and Fourier Transforms Infrared measurements at 90% moisture. This resulted in increased viscosity and the formation of a loose gel network structure. Subsequently, maintaining the temperature at 95 °C caused a decrease in viscosity as most granules disappeared, forming a reorganized flaky gel structure with larger pores. As the temperature decreased, gel porosity reduced. In high amylose content starch, the viscosity remained low and granules were partially gelatinized since the heating temperature was below the gelatinization temperature. This study is the first to detail starch multilevel structural dynamics during RVA gelatinization., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study explored the effect of stirred media mill (SMM) processing on the acid-induced gelling properties of pea protein. Results showed that SMM treatment enhanced the gel strength from 75.06 g to 183.89 g and increased the water holding capacity from 46.64 % to 73.50 %. The minimum gelation concentration achieved for SMM-treated pea protein was 4 %, significantly lower than that of heat-pretreated pea protein (9 %). SMM decreased protein aggregate size from 104 μm to 180 nm. Microscopy analysis revealed that the small aggregates facilitated the formation of uniform gel networks with tight connections. Linear rheology indicated that small protein aggregates resulted in slower gelation rates with a higher G' for the formed gels. The SMM-pretreated protein gel showed strain hardening, shear thinning behaviors, and satisfactory stability to withstand large-amplitude oscillatory shear. Overall, SMM emerges as a promising technology for producing protein gel products with strong mechanical attributes and customizable rheological properties., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Salted hen egg yolks are less oily and less flavorful than salted duck egg yolks. However, hen eggs have a more adequate market supply and have a broader application prospect than duck eggs. In the present study, egg yolks, plasma, and granules were dehydrated by adding 1% NaCl to simulate traditional curing process of salted egg yolk. The changes in the pickling process of hen egg yolks (HEY) and duck egg yolks (DEY) plasma and granules were compared to reveal the gelation mechanism and the underlying causes of quality differences in salted HEY and DEY. Salted HEY can be compared with the changes in DEY during the pickling process to provide a theoretical basis for the quality improvement of salted HEY to salted DEY., Results: The results showed that both plasma and granules were involved in gel formation, but exhibited different aggregation behaviors. Based on the intermolecular forces, the HEY proteins achieved aggregation mainly through hydrophobic interactions and DEY proteins mainly through covalent binding. According to spin-spin relaxation time, HEY gels immobilized a large amount of lipid and interacted strongly with lipids. DEY gels showed much free lipid and had weak interaction with lipid. The microstructure showed that HEY proteins were easily unfolded to form a homogeneous three-dimensional gel network structure after salting, whereas heterogeneous aggregates were formed to hinder the gel development in DEY. Changes in protein secondary structure content showed that pickling can promote the transformation of the α-helices to β-sheets structure in HEY gels, whereas more α-helices structure was formed in DEY gels., Conclusion: The present study has demonstrated that different gelation behaviors of hen and duck egg yolk proteins (especially in plasma) through salting treatment led to the difference in the quality of salted HEY and DEY. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Polymeric foamed materials are among the most widely utilized technologies for oil spill accidents and releases of oil-contaminated wastewater oil due to their porosity to absorb and separate oil/water effectively. However, a major limitation of traditional polymeric foams is their reliance on an ad/absorption mechanism as the sole method of oil capture, leading to potential oil leakage once their saturation point is exceeded. Tri-block polymer styrene-ethylene-butylene-styrene (SEBS) is a fascinating absorbent material that can bypass this limitation by both capturing oil and providing a sealing mechanism via gelation to prevent oil leakage due to its unique chemical structure. SEBS foams are produced via simultaneous crosslinking and foaming that results in an impressive expansion ratio of up to 15.2 with over 93% porosity. Most importantly, the SEBS foams show great potential as oil absorbents in spill remediation, demonstrating rapid and efficient oil absorption coupled with superhydrophobic properties. Moreover, the unique interaction between the oil and SEBS enables the formation of a physical gel, acting as an effective barrier against oil leakage. These findings indicate the potential for commercializing SEBS foam as a viable option for geotextiles to mitigate oil spill concerns from infrastructures., (© 2024 The Author(s). Macromolecular Rapid Communications published by Wiley‐VCH GmbH.)

Significant challenges remain for the remediation of chlorinated-solvent plumes in groundwater, such as trichloroethene (TCE) and tetrachloroethene (PCE). A novel slow-release permanganate gel (SRP-G) technique may show promise for the in-situ treatment (remediation) of chlorinated contaminant plumes in groundwater. A series of laboratory experiments were conducted to characterize the primary physical factors that influence SRP-G gelation processes to optimize SRP-G performance for plume treatment. Specifically, experiments were conducted to quantify gel zeta potential, particle size distribution, and viscosity to determine SRP-G gelation characteristics and processes. These experiments tested various concentrations of two SRP-G amendment solutions (NaMnO 4 and KMnO 4 ) prepared with 30-wt.% and 50-wt.% colloidal silica to determine such influences on zeta potential, particle size distribution, and viscosity. The results of this study show that SRP-G solutions with low zeta potential and relatively high pH favor more rapid SRP-G gelation. The concomitant interaction of the predominantly negatively charged colloidal silica particles and the positively charged dissociated cations (Na + and K + ) in the SRP-G solution had the effect of stabilizing charge imbalance via attraction of particles and thereby inducing a greater influence on the gelation process. Gel particle size distribution and changes in viscosity had a significant influence on SRP-G solution gelation. The addition of permanganate (NaMnO 4 or KMnO 4 ) increased the average particle size distribution and the viscosity of the SRP-G solution and decreased the overall gelation time. SRP-G amendments (NaMnO 4 or KMnO 4 ) prepared with 50-wt.% colloidal silica showed more effective gelation (and reduced gelation time) compared to SRP-G amendments prepared with 30-wt.% colloidal silica. Under the conditions of these experiments, it was determined that both the 7-wt.% NaMnO 4 solution and 90 mg/L KMnO 4 solution using 50-wt.% colloidal silica would be the optimal injection SRP-G solution concentrations for this in-situ treatment technique., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Limited proteolysis, CaCl 2 and carboxymethyl cellulose (CMC) have individually demonstrated ability to increase the gel strength of laboratory-extracted plant proteins. However, the syneresis effects of their combination on the gelling capacity of commercial plant protein remains unclear. This was investigated by measuring the rheological property, microstructure and protein-protein interactions of gels formed from Alcalase hydrolyzed or intact pea proteins in the presence of 0.1 % CMC and 0-25 mM CaCl 2 . Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed the molecular weight of pea protein in the mixture were < 15 kDa after hydrolysis. The hydrolysates showed higher intrinsic fluorescence intensity and lower surface hydrophobicity than the intact proteins. Rheology showed that the storage modulus (G') of hydrolyzed pea protein (PPH)-based gels sightly decreased compared to those of native proteins. 5-15 mM CaCl 2 increased the G' for both PP and PPH-based gels and decreased the strain in the creep-recovery test. Scanning electron microscopy (SEM) showed the presence of smaller protein aggregates in the PPH-based gels compared to PP gels and the gel network became denser, and more compact and heterogenous in the presence of 15 and 25 mM CaCl 2 . The gel dissociation assay revealed that hydrophobic interactions and hydrogen bonds were the dominant forces to maintain the gel structure. In vitro digestion showed that the soluble protein content in PPH-based gels was 10 ∼ 30 % higher compared to those of the PP counterpart. CaCl 2 addition reduced protein digestibility with a concentration dependent behavior. The results obtained show contrasting effects of limited proteolysis and CaCl 2 on the gelling capacity and digestibility of commercial pea proteins. These findings offer practical guidelines for developing pea protein-based food products with a balanced texture and protein nutrition through formulation and enzymatic pre-treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Co-solutes such as sucrose and sugar alcohol play a significant part in low methoxyl pectin (LMP) gelation. To explore their gelation mechanism, we investigated the gelation behavior of LMP in the presence of erythritol and sucrose with Ca 2+ . Results revealed that the introduction of erythritol and sucrose improved the hardness of the gels, fixed more free water, accelerated the rate of gel structuring, and enhanced the gel strength. FT-IR confirmed the reinforced hydrogen bonding and hydrophobic forces between the pectin chains after introducing co-solutes. And it could be observed clearly by SEM that the cross-linking density of gel network enhanced with co-solutes. Furthermore, gel disruption experiments suggested the presence of ionic interaction, hydrogen bonding, and hydrophobic forces in LMP gels. Finally, we concluded that the egg-box regions cross-linked only by LMP and Ca 2+ were too weak to form a stable gel network structure. Adding co-solutes could increase the amount of cross-linking between pectin chains and enlarge the cross-linking zones, which favored the formation of a dense gel network by more hydrogen bonding and hydrophobic forces. Sucrose gels had superior physicochemical properties and microstructure than erythritol gels due to sucrose's excellent hydration capacity and chemical structure characteristics., Competing Interests: Declaration of competing interest We declare that no known competing financial interests or personal relationships could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

This study aims to evaluate the structure of ions-regulated gelation of egg white protein (EWP) via aggregation kinetics model, which was built by monitoring turbidity. Results showed that compared with NaCl and KCl, the addition of Na 2 SO 4 increased free sulfhydryl content, surface hydrophobicity and particle size of EWP significantly, while weakened the order of secondary structure. Hence, strengthened gel network structure was observed with higher porosity, which improved the texture profiles and rheological properties of EWP gels. Based on these phenomena above, the relationship between aggregation behavior and gelling properties with ions was further investigated by aggregation kinetics model and principal component analysis. Because of the enhancement of protein interactions, the aggregation growth rate with Na 2 SO 4 was much faster than the samples with NaCl, which reflected over-aggregation due to the accelerated nucleation process and resulted in firmed gel network structure., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The mechanism by which arthropods (e.g., spiders and many insects) can produce silk fibres from an aqueous protein (fibroin) solution has remained elusive, despite much scientific investigation. In this work, we used several techniques to explore the role of a hydration shell bound to the fibroin in native silk feedstock (NSF) from Bombyx mori silkworms. Small angle X-ray and dynamic light scattering (SAXS and DLS) revealed a coil size (radius of gyration or hydrodynamic radius) around 12 nm, providing considerable scope for hydration. Aggregation in dilute aqueous solution was observed above 65 °C, matching the gelation temperature of more concentrated solutions and suggesting that the strength of interaction with the solvent (i.e., water) was the dominant factor. Infrared (IR) spectroscopy indicated decreasing hydration as the temperature was raised, with similar changes in hydration following gelation by freezing or heating. It was found that the solubility of fibroin in water or aqueous salt solutions could be described well by a relatively simple thermodynamic model for the stability of the protein hydration shell, which suggests that the affected water is enthalpically favoured but entropically penalised, due to its reduced (vibrational or translational) dynamics. Moreover, while the majority of this investigation used fibroin from B. mori , comparisons with published work on silk proteins from other silkworms and spiders, globular proteins and peptide model systems suggest that our findings may be of much wider significance.

Wax-based oleogels attract considerable attention for their perfect gelation properties, but the waxy mouthfeel severely limits their implementation in food. Herein, we developed a novel strategy via designing the crystal network to produce wax-based oleogels with a suitable mouthfeel. Four natural waxes with different melting points were selected as oleogelators to investigate the gelation behavior. All waxes at 5 wt% concentrations could form stable oleogels with low-frequency dependence. Especially, rice bran wax (RBW) and beeswax (BW) with high oil-binding capacity indicated that the ordered crystal network with fiber or needle-like morphology is more suitable for trapping liquid oil. Interestingly, China lacquer wax (ZLW) presented satisfactory oral melting characteristics according to the melting properties. Subsequently, to enhance the structure of ZLW-oleogel, RBW and BW with desirable crystal networks were added at varying mass ratios (100:0, 75:25, 50:50, 25:75, and 0:100). The binary oleogels exhibited monotectic behavior from thermodynamic phase diagrams. The polarization microscope indicated that similar needle-like crystals in BW/ZLW system enhanced the order of network structure, while long fiber-like crystals by RBW dominated the crystallization of RBW/ZLW binary oleogels. Finally, the BW/ZLW binary oleogels with ratios of 25:75 and 50:50 showed no-waxy mouthfeels in sensory analysis. These findings provide strong theoretical support for the application of wax-based oleogels in plastic fats replacement. PRACTICAL APPLICATION: Natural wax-based oleogel has been widely investigated due to the high oil binding capacity and perfect gelation properties. But its waxy mouthfeel severely limits the application in the food industry. In this study, oleogels with no-waxy an mouthfeel were obtained by designing wax-blend crystalline network. These findings provide strong theoretical support for the application of wax-based oleogels in plastic fats replacement., (© 2021 Institute of Food Technologists®.)

Gel properties of hydrogel-forming by Ala-Lys dipeptide (AK) and iota-carrageenan (ι-C) were investigated by rheological behavior, fourier transform infrared analysis, cryo-scanning electron microscopy, low field-NMR relaxometry and magnetic resonance imaging. Iota-carrageenan was changed from a liquid to a gel with the addition of AK, and the existence of AK significantly increased the storage modulus (G') of ι-C from 590.4 to 1077.8 Pa. In the ι-C/AK gel, the blue-shift of OH stretching and water deformation were observed, meanwhile, the presence of amide I band at 1682 cm -1 was observed. The network of ι-C/AK gel showed a dense honeycomb structure with flocculating continuous phase and rough entanglement morphology. After adding AK, the water free in the pores of ι-C entered the ι-C/AK gel matrix, and the binding capacity of bound water was enhanced. These scenarios proved that the AK as the cationic dipeptide could control the conversion of negatively charged ι-C from an original random structure to a helical structure due to electrostatic interactions and hydrogen bonds. This study provides a new opportunity for the peptides into carbohydrate-based gel matrices, which could provide insights for the further application of ι-C/AK gels in the fields of food industry, tissue engineering and drug delivery., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The current study was conducted to investigate the effect of different high intensity ultrasound (HIU) amplitudes on the gelation properties of wooden breast (WB) meat batter prepared with 1% and 2% NaCl. Results indicated that HIU effectively enhanced the water holding capacity (WHC) of WB at 1% and 2% NaCl, and enabled WB to obtain better WHC than the normal. The thermal stability of WB was affected by HIU, and the difference of G' end between WB and normal was reduced at 2% NaCl. HIU continuously decreased the particle size of WB at 1% NaCl, whereas opposite trends were observed at 2% NaCl. In addition, HIU transformed α-helix structure of WB to random coil at 1% NaCl, whereas to β-sheet structure at 2% NaCl. Overall, HIU can be utilized to improve the gelation properties of WB meat with the potential to produce low- and common-salt gel-type meat products., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The effects of different particle sizes (90-µm and 200-µm) and contents (1.5% and 3%) of water-insoluble dietary fibers (IDF) on the gelation properties of duck myofibrillar protein (MP) were explored. The results showed that the addition of IDF improved the gel strength and water holding capacity of MP compared with the control (P < 0.05). IDF reinforced the formation of network structure and the viscoelasticity of gel; 1.5% 200-µm IDF reached the maximum among these treatments. PT 21 of the gel with IDF was higher than that of the control (P < 0.05), revealing that the addition of IDF accelerated the transformation of free water into immobilized water within the gel matrix. An ordered flaky gel network with small water holes was responsible for the increase of fractal dimension of the gel with IDF. Water distribution and viscoelasticity are the critical factors that IDF affects the gel properties of duck MP., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Various bond disrupting agents including NaCl, GuHCl, urea, and SDS were introduced to investigate the intermolecular interactions between scallop (Patinopecten yessoensis) male gonad hydrolysates (SMGHs) and κ-carrageenan (κ-C), which were monitored by changes in rheological property, water distribution, conformation characterization and microstructure by using rheometer, low field-NMR relaxometry, Fourier transform infrared (FTIR) spectroscopy, cryo-scanning electron microscopy (cryo-SEM), and confocal laser scanning microscopy. The results showed that the bond disrupting agents deteriorated the rheological property of SMGHs/κ-C in a dose-dependent manner. Indeed, at the same concentration of 2 M, NaCl deteriorated the SMGHs/κ-C more obviously than GuHCl and urea. In addition, SMGHs/κ-C with bond disrupting agents possessed higher relaxation times including T 21 and T 23 , indicating the migration to free water direction of bound and free water. Moreover, the FITR results showed the red-shift in water regions (amide A and B bands), amide I and II bands, and indicated the breakdown of hydrogen bonds and electrostatic interactions, indicating a disordered structure in SMGHs/κ-C by various bond disrupting agents. Furthermore, cryo-SEM results showed the change of SMGHs/κ-C from a homogeneous network to a looser and ruptured one with larger void spaces, and indicated the disrupted and tattered microstructure of SMGHs/κ-C by various bond disrupting agents. Additionally, SMGHs/κ-C as well showed less aggregates stained by RITC by bond disrupting agents. These results suggest that electrostatic interactions would be mainly involved in the maintenance of SMGHs/κ-C gel network. This study could provide theoretical and methodological basis for hydrogel products with modified gel strength and microstructure by understanding the intermolecular interactions in gel system. PRACTICAL APPLICATION: Scallop (Patinopecten yessoensis) male gonads as a high-protein part of scallop, is usually discarded during processing despite its edibility. In recent years, scallop male gonads are regarded as good sources to develop protein matrices due to their high protein content and numerous nutrients. In this study, scallop male gonad hydrolysates (SMGHs) were obtained by trypsin-treated process. The considerable gelation behavior of SMGHs indicated that the SMGHs could be potentially utilized as a novel thickener and additive in production of kamaboko gels, can, sausage and spread with marine flavor., (© 2021 Institute of Food Technologists®.)

Naturally-sourced oligoguluronate (GB) has Ca-binding ability and can be employed to modulate Ca-dependent gels. Here soy protein isolate (SPI) gel was used as a model to investigate the influence of GB on the microstructure and properties of Ca-dependent food gels. The results showed that GB significantly decreased the storage modulus (G'), mechanical strength, elasticity, hardness and chewiness of SPI gels. Among all samples, the gel containing 30 mM GB showed the most compact network structure and thus the highest water holding capacity of 77.5 %. It should be noted that Ca-GB dimers were beneficial to the gel formation and can modify the gel properties but have no impact on the gelation kinetics. The findings gained in this study confirmed the great potential of GB in modulating the structure and properties of Ca-dependent gels, thereby obtaining food products with desired characteristics (e.g., soft and brittle tofu)., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this paper, changes in physicochemical properties, gel structure and in vitro digestion of marinated egg with spice or tea during braising were investigated. Results indicated that the moisture content and surface hydrophobicity of marinated egg white showed an overall decreased trend. The springiness of marinated egg white showed an increased trend, and the hardness in the late stage showed an increased trend. Microstructure showed that compact gel structures formed many holes during the braising. Intermolecular forces showed that ionic bonds and disulfide bonds played a dominant role in the marinated egg white. Secondary structure showed that the β-turn showed a decreased trend, contrary to that of random coils and α-helices. Appropriate braising increased the digestibility of marinated egg white, but excessively long-time braising could reduce it. Both spice and tea braising could improve the gel strength of protein, and the tea braising was also slightly better than spice braising., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Marine oil spills is one of the frequent natural disasters that adversely affect the economy and ecosystem. A variety of methods have been developed to combat marine oil spills. However, none of these methods is ideal and universal for tackling different kinds of oil spills. In addition, most of these methods do not offer the possibility for recovering the spilt oil. There is great interest in developing novel and better methods for combating marine oil spills that allow recovery of the spilt oil. The use of low molecular weight organogelators that can selectively congeal oil from oil-water mixtures have been proposed to be useful for oil spill recovery. From this initial proposal, the area has progressed gradually towards their practical implementation. The advancements and novel concepts in this area are reviewed., (© 2020 Wiley-VCH GmbH.)

In this work, we investigate the role of folding/unfolding equilibrium in protein aggregation and formation of a gel network. Near the neutral pH and at a low buffer ionic strength, the formation of the gel network around unfolding conditions prevents investigations of protein aggregation. In this study, by deploying the fact that in lysozyme solutions the time of folding/unfolding is much shorter than the characteristic time of gelation, we have prevented gelation by rapidly heating the solution up to the unfolding temperature (~80 °C) for a short time (~30 min.) followed by fast cooling to the room temperature. Dynamic light scattering measurements show that if the gelation is prevented, nanosized irreversible aggregates (about 10-15 nm radius) form over a time scale of 10 days. These small aggregates persist and aggregate further into larger aggregates over several weeks. If gelation is not prevented, the nanosized aggregates become the building blocks for the gel network and define its mesh length scale. These results support our previously published conclusion on the nature of mesoscopic aggregates commonly observed in solutions of lysozyme, namely that aggregates do not form from lysozyme monomers in their native folded state. Only with the emergence of a small fraction of unfolded proteins molecules will the aggregates start to appear and grow.

In this study, we investigated the gellan gelation mechanism induced by Glucono-δ-lactone (GDL) addition, and subsequently we further fabricated a series of thermally irreversible emulsion gels with the GDL-induced gel matrix as the continuous phase and the methyl cellulose (MC) stabilized emulsion as the dispersed phase. The results showed that GDL- induced gellan gelation was both a time- and temperature-dependent process, which was similar to the gelation process of NaCl-induced gellan gels, but with a higher temperature-dependence. Moreover, GDL-induced gel had a significantly higher rupture strength and the resulting gel did not melt on heating, meaning that the GDL-induced gellan gel can be deemed thermally irreversible. This is because decreasing pH is commonly more effective in promoting gellan gelation. Besides, by mixing the MC-stabilized emulsion with a hot gellan sol, followed by adding GDL, we fabricated the emulsion gels with a wide range of oil phase fraction (0-30%). The emulsion gels exhibited good thermal stability, without melting and oil droplet coalescence observed when heating the gels in a boiling water bath for 30 min. Conclusively, our results may deepen the understanding on gellan gelation induced by GDL and also broaden the utilization of gellan in building gel-related food structures., Competing Interests: Declaration of competing interest The authors declare no conflict of interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In the current study, we found an interesting phenomenon that fresh egg white (EW) undergo the sol-gel-sol transition with alkali treatment. The transformation behavior at different alkalinity (1.5%, 2.0%, and 2.5%) was investigated. As the gel formed, the hardness, lightness, surface hydrophobicity and the total number of identified peptides increased, and then, remarkable reduction when the gel collapsed. Rheological behavior indicated that the viscosity varied with shear rate. Fourier transform infrared spectroscopy (FTIR) showed that β-sheets gradually decreased as the α-helices increased during gel-sol transformation. The quantification of EW peptides analysis revealed that there was no dramatic correlation between the number of identified peptides and alkalinity. It was concluded that the sol-gel-sol transition was strongly dependent on alkali levels, moreover, high concentration promoted gel formation as well as liquefaction. The EW transformation behavior induced by alkali had a significant effect on protein aggregation and denaturation, and further changed physicochemical properties., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this study, a class of interpenetrating network (IPN) gels were successfully fabricated based on glucono-δ-lactone (GDL) induced gelation of mixed alginate (Alg) and deacylated gellan (gellan) systems. The IPN gels were prepared by co-hydrating a mixed Alg and gellan powder, followed by adding GDL and calcium carbonate (CaCO 3 ) in sequence to initiate the gelation. It was found that Alg and gellan can form independently a gel network, with no significant interaction between the two types of gel networks observed, as indicated by the results of gel strength determination, scanning electron microscope (SEM) observations and thermogravimetry (TG) and derivative thermogravimetric (DTG) analyses. Moreover, the mixing ratio of Alg to gellan significantly affected the physical properties of the fabricated gels. With increasing Alg to gellan ratio, the gels tended to become more elastic, and to show a higher rehydration rate and rehydration extent. Overall, these tunable properties may allow the fabricated gels to find potential applications in designing or optimizing the structures of gel-related food products., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Salt addition and thermal pretreatment were used to improve the freeze-thaw stability of Pickering emulsion gels (PEGs) stabilized by compound proteins. Thermal pretreatment with the presence of salt could promote the formation of gel-like structure and alter the interactions between the emulsion droplets of PEGs, sequentially increase the resistance of the PEGs to water separation, creaming, and oiling-off during freeze-thaw cycles (freeze at -20 °C for 22 h and thawing at 37 °C for 2 h), especially at higher salt levels (200 and 500 mM). Microstructures indicated that the presence of high salt concentration and heat pretreatment could help to maintain the gel-like structures of PEGs during freeze-thaw cycles. Overall, our results showed that novel viscoelastic food materials with good freeze-thaw stability can be produced by controlling the electrostatic interactions between the emulsion droplets and the gelation of emulsion gels. These materials may be useful for application in frozen food products., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Soy protein hydrolysates (SPH) with different degrees of hydrolysis (DH 0-16%) were obtained by varying the time of hydrolysis with bromelain. The objective of this study was to evaluate how selected techno-functional properties (gelation, emulsification) of SPH were affected by the presence of a non-gelling polysaccharide. A slight hydrolysis was beneficial to increase gel strength. Also, the emulsifying activity was improved for low DHs, whereas hydrolysis was detrimental for emulsion stability. Under certain conditions the presence of the non-gelling polysaccharide was beneficial to improve SPHs' functional properties, but the effect was in general complex and strongly dependent on both biopolymers' concentration and molecular weight. Nevertheless, it was demonstrated that by using SPH and galactomannan mixtures and controlling the biopolymers' concentration and molecular weight, improved functionalities can be obtained with useful applications in food formulation., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The effect of glucose oxidase (GOx) catalytic oxidation on the efficacy of gallic acid (GA) to modify the chemical structure and gelling behavior of myofibrillar protein (MP) was investigated. In contrast to non-oxidized MP samples where GA induced very little changes, GA (0, 6, 30, and 60 µmol/g MP) under GOx treatment promoted sulfhydryl and amine loss (up to 58% and 49%, respectively). The attenuation of intrinsic tryptophan fluorescence in the GA/GOx-treated MP corroborated the finding. The gelling capacity of MP, corresponding to disulfide and non-disulfide bond formation in protein aggregates, was markedly enhanced by 60 µmol GA under GOx, up to 86% in gel storage modulus G' and 53% in gel strength. The GOx-aided GA modification of MP could be a potential ingredient strategy in meat processing to promote textural attributes of cooked products., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

One approach to avoid production of acid whey during the manufacture of high-protein yogurt and related products is to concentrate the milk before fermentation. However, the resultant gels are firm so that stirring in the tank and further processing are difficult on an industrial scale. We hypothesize that power ultrasound (US) during fermentation softens the gel because sound waves cause cavitation and strong shear forces in the fluid. Skim milk was standardized to different protein contents up to 12%, heated (85°C, 30 min), and acidified with thermophilic or mesophilic starter cultures. An excessive increase in gel firmness as a function of protein content was detected. In the next series of experiments, US was applied during fermentation. Milks (10% protein) were acidified at 43.5°C and sonicated from pH 5.8 to 5.1 with a sonotrode (20 kHz, 20 W). Immediately after fermentation, gels were agitated using a rheometer with a vane geometry. The maximum torque required to break the gel was reduced by 75% following US, and gel firmness was reduced by 80%. Gels were then processed into stirred yogurt and analyzed. Sonicated samples were smoother with fewer large aggregates. Confocal laser scanning microscopy images suggested a less cohesive structure and more compact microgel particles, resulting in reduced viscosity. We concluded that US is a promising tool to weaken the gel and facilitate further processing. This enables new approaches for the manufacture of Greek yogurt, particularly in regard to avoiding production of acid whey and developing products with novel textures., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Purpose: Amorphous lurasidone hydrochloride (LH) showed decreased dissolution behavior in comparison to crystalline LH owing to gelation during dissolution as reported in our previous study. The current study aims to investigate external factors including temperature and ionic strength on the gelation and hence the dissolution of amorphous LH., Methods: Dissolution tests of amorphous LH were performed under different temperatures and buffer ionic strengths. The formed gels were characterized by rheology study, texture analysis, PLM, SEM, DSC, XRPD and FTIR., Results: With the increase of temperature and ionic strength of medium, the dissolution of amorphous LH decreased, while the strength, hardness and adhesiveness of in situ formed gel enhanced. Amorphous LH converted into its crystalline state during dissolution and the crystallization rate was affected by medium conditions. With medium temperature increasing from 30°C to 45°C, the gel microstructure changed from interconnecting fibrillar network to spherical particle aggregate. On the other hand, the formed spherulitic gel aggregate exhibited increased particle size when increasing the ionic strength of medium., Conclusions: With increase of temperature and ionic strength, the gel strength of in situ formed gel from amorphous LH enhanced with more compact microstructure, subsequently leading to decreased dissolution profiles.

Previous studies have demonstrated that oligoguluronate (guluronate block extracted from alginate, GB) was an efficient modulator of the gelation and gelling properties of macromolecular alginate in the presence of calcium. Here we report totally different modulatory effects of the oligomer when used to modify the gelation of low methoxyl pectin (LMP). GB was found to promote the gelation of LMP in the range of R ([Ca]/[guluronate + galacturonate]) < 0.25 and could make non-gelling systems gellable. This is significantly different from the case of alginate where no gelation could be induced at all. In the range of 0.25 < R < 0.60, the addition of GB was found to inhibit the gelation of LMP, whereas it had a negligible effect on the gelation of alginate as long as a fixed R was considered. In the range of R > 0.60, GB was found to promote the gelation of LMP again, which is similar to the case of alginate. The results were in consistence with microstructural observations by AFM. The different modulatory effects of GB were thought to arise from the different gelation mechanisms of LMP and alginate, that is, a progressive dotting growth of LMP dimers vs. a critical zippering growth of alginate dimers during Ca-induced crosslinking. The mechanism of GB modulating the gelation of LMP was proposed and compared to that for alginate., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The aim of this work was to investigate how the heat-induced gelation of micellar casein (MC)-plant protein mixtures in aqueous solution is affected by protein composition (MC/plant proteins = 100/0 to 0/100) and total protein content (4%, 6% and 8% w/w) at pH 5.8 and 6.0. Two types of plant proteins were used: soy proteins (SP) and pea proteins (PP). Storage moduli (G') were measured during heating ramps from 20 to 90 °C and heat-induced gelation was characterised by a sharp increase in G' at a critical temperature (T c ). The gel stiffness (G el ) was determined after 1 h at 90 °C and the microstructure before and after heating was investigated by confocal laser scanning microscopy (CLSM). T c was found to increase with increasing the fraction of MC replaced by SP or PP, due to binding of calcium to the plant proteins. The effect was stronger for SP, which bound calcium more efficiently than PP. T c decreased with decreasing pH, possibly caused by decreased electrostatic repulsion and increased calcium release from MC. G el increased with increasing total protein content and did not depend significantly on the pH. Interestingly, G el showed a minimum as a function of the plant protein fraction (40% for SP and 70% for PP) in the mixtures. It is concluded that MC and plant proteins did not co-aggregate in the mixtures during heating, and that each type of protein formed networks independently., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The purpose of this study is to highlight the surface and size effects of the nanopores on the thermodynamics and kinetics of gelation. The effects have been probed by applying differential scanning calorimetry to poly(vinylidene fluoride) solutions in tetraethylene glycol dimethyl ether (tetraglyme) and γ-butyrolactone. Nanoconfinement has been accomplished by introducing gels into native and organically modified silica nanopores (4⁻30 nm). Nanoconfinement has produced two major effects. First, the heat of gelation has decreased three to four times compared to that for the bulk systems. Second, the temperature of gelation has increased by ~40 °C (tetraglyme based systems) and ~70 °C (γ-butyrolactone based systems), the increase being stronger in native nanopores. The effects are discussed in terms of acceleration of gelation due to heterogeneous nucleation at the confining surface, and retardation of gelation due to constricted polymer chain mobility in the middle of the pore volume. Calorimetric data have been subjected to isoconversional kinetics analysis. The obtained temperature dependencies of the activation energies of gelation have been interpreted in the frameworks of the nucleation model of Turnbull and Fisher. The results suggest that nanoconfinement leads to a lowering of both the free energy of nucleation and activation energy of diffusion.

The influence of cyclodextrins (CDs) on the rheological and structural properties of κ-carrageenan (κ-CA) gel was investigated. Gelling temperature (T g ) of κ-CA was improved by CDs present in the system. Variation of the Herschel-Bulkley model parameters indicates that the addition of CDs increases plasticity of the κ-CA sol. Scanning electronic micrographs show that networks of κ-CA become flat and firm after CDs were added. κ-CA gel containing methyl-β-CD shows the most uniform and fine network structure. Moreover, a proposed model of CDs in κ-CA phase was provided. The influence of CDs on κ-CA gelation was mainly through (i) the exclusion of CDs from κ-CA in the sol state, (ii) the regular rearrangement of κ-CA random coils influenced by CDs in the sol state, (iii) the binding of CDs to the κ-CA surface by hydrogen bonds in the gel., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Solvents, accounting the majority of the organogel system, have a tremendous impact on the characteristics of gels. To date, there is a large variety of organogel systems; relatively few have been investigated in the field of structure-solvent correlation. Here, a series of solvent parameters were applied to explore the role of solvent effect on network forming and gel property, intending to build the connection between the precise solvent parameter and gel property. Among the solvent parameters, Kamlet-Taft Parameters and Hansen solubility parameters can distinguish specific types of intermolecular interactions, which could correlate solvent parameter with the gel property. From an analysis of the morphologies obtained from POM and SEM, the gelator structure has an impact on its self-assembly. For possible conformations, the gelators were investigated through XRD. The investigation of solvent-property relationship will provide a theoretical basis for controllable drug delivery implants.

D,L-Methionine was chosen as a starting material for the preparation of a new gelator N-10-undecenoyl-D,L-methionylaminooctadecane (DL-Met-R 18 ). Three oligo (dimethylsiloxane)-containing gelators, DL-Met-R 18 /Si 3 , DL-Met-R 18 /Si 7-8 , and DL-Met-R 18 /Si 14-15 , were also prepared from DL-Met-R 18 by hydrosilylation reactions. Their gelation abilities were evaluated on the basis of the minimum gel concentration using nine solvents. Compound DL-Met-R 18 was able to gelate liquid paraffin and silicone oil, but it crystallized in most solvents. However, DL-Met-R 18 /Si 7-8 resulted to be the best gelator, gelling eight solvents at low concentrations. The results of gelation tests demonstrated that the ability to form stable gels decreases in the following order: DL-Met-R 18 /Si 7-8 ≈ DL-Met-R 18 /Si 14-15 > DL-Met-R 18 /Si 3 >> DL-Met-R 18 . The aspects and thermal stabilities of the gels were investigated using three-component mixtures of solvents composed of hexadecyl 2-ethylhexanoate, liquid paraffin, and decamethylcyclopentasiloxane (66 combinations). DL-Met-R 18 /Si 3 , DL-Met-R 18 /Si 7-8 , and DL-Met-R 18 /Si 14-15 could form gels with all these mixed solvent combinations; particularly, DL-Met-R 18 /Si 7-8 gave rise to transparent or translucent gels. FT-IR spectra suggested that the formation of hydrogen bonds between the NH and C=O groups of the amides is one of driving forces involved in the gelation process. Aggregates comprising three-dimensional networks were studied by transmission electron microscopy. Moreover, the viscoelastic behavior of the gels was investigated by rheology measurements.

Phase transitions of linear multivalent proteins control the reversible formation of many intracellular membraneless bodies. Specific non-covalent crosslinks involving domains/motifs lead to system-spanning networks referred to as gels. Gelation transitions can occur with or without phase separation. In gelation driven by phase separation multivalent proteins and their ligands condense into dense droplets, and gels form within droplets. System spanning networks can also form without a condensation or demixing of proteins into droplets. Gelation driven by phase separation requires lower protein concentrations, and seems to be the biologically preferred mechanism for forming membraneless bodies. Here, we use coarse-grained computer simulations and the theory of associative polymers to uncover the physical properties of intrinsically disordered linkers that determine the extent to which gelation of linear multivalent proteins is driven by phase separation. Our findings are relevant for understanding how sequence-encoded information in disordered linkers influences phase transitions of multivalent proteins.

The effects of lotus root amylopectin (LRA) on the formation of whey protein isolate (WPI) gels were investigated at the concentration range from 0 to 1.0% (w/v) by determining the texteral, thermal and rheological properties. Results exhibited these properties of WPI gels could be significantly enhanced by the addition of LRA in a concentration-dependent manner. Compared the gel with free of starch, the gel strength, water holding capacity and thermal transition temperature of WPI gel containing 1% (w/v) amylopectin were enhanced by 12.7-fold, 24.9% and 3.6°C, respectively. According to the analysis of scanning electron microscopy, colorimetric reaction and Fourier transform infrared spectroscopy measurements, it was concluded that the LRA-induced enhancement of WPI gel properties was possibly attributed to the formation of stable three-dimensional gel network, increased contents of reactive sulfhydryl group, CN bond and/or NH bond. Results suggested that LRA might be a good gel modifier., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The effects of sugarcane dietary fiber (SDF) on the gelation properties of porcine myofibrillar proteins (MP) were studied to understand its mechanism of action in improving gel functionality. Rheological tests on all composite gels (MP with SDF) showed the visco-elastic nature of MP, but the G' significantly increased with contents of SDF and with particle size (P<0.05). However, the δ exhibited the opposite effect. Light microscopy suggested that SDF affected moisture distribution in the gel by drawing water from MP and homogenously embedded in gelation. It is proposed that during the heating the more concentrated MP promoted the unfolding of MP chains and facilitated the formation of β-sheet instead of α-helices, leading to a compact and homogenous three-dimensioned network. These results indicated that the SDF changed the water distribution and resulted in the enhanced gelation which reacted to firmly bind SDF and form a synergistic interaction system., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Phase behaviors of mixtures of myofibrillar protein and κ-carrageenan at different mixing ratios and temperatures were examined by digital images and confocal scanning laser microscopy, showing that that the extent of phase separation was enhanced as the ratio of polysaccharides and temperature increased. The zeta potential of the mixtures became less negative as the protein ratio increased, and the complex became saturated at or above the protein/κ-carrageenan ratio of R 4 (3.2%:0.8%). Gelation process performed by dynamic rheological analysis demonstrated that the presence of carrageenan decreased the gelation temperature but increased the storage modulus. Analysis of the microstructures of the mixed gels showed that the networks were significantly influenced by the concentrations of κ-carrageenan. The present work could be applied to evaluate the mechanism of competition between phase separation and gelation in mixtures of proteins and polysaccharides., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

High pressure (HP) was applied to pre-rigor rabbit muscles (PRRMs) for the manufacture of value-added gel-type products. A 2×3 factorial design was adopted for HP-treatment (100, 200 and 300MPa for 15 or 180s) to PRRMs. The HP-treated meat was used for gel preparation and determination of water mobility properties and textural profiles. Salt-soluble meat proteins (SSMP) were then extracted from meat for estimating the tertiary conformational changes (hydrophobic and sulfhydryl groups). The water-holding capacity of treated samples increased significantly (P<0.05) except for those treated at 300-180 (MPa-s). The hardness, cohesiveness and chewiness were significantly improved (P<0.05) by moderate HP-treatments (100-200MPa for 15 or 180s). HP-induced the de-polymerization of some protein components, together with unfolding and refolding of protein tertiary conformations, partly explaining the observed functionality changes. In conclusion, application of moderate HP to PRRM modified the protein conformation in a manner that improved the functional properties of gels., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Nuclear magnetic resonance was used to study water proton transverse relaxation in oat β-glucan aqueous solutions during storage. The molecular weights of the samples ranged from 112 to 494kDa. The polysaccharide structure was identified by IR, GC-MS, NMR spectroscopy, and high performance anion exchange chromatography. In 1% solutions, 494kDa β-glucan formed stable solution phase. Aggregates were generated in the solution of low molecular weight polysaccharide. The transverse relaxation time of water associated with the aggregate microphase was about 15ms. The majority of the solution was bulk water, with a relaxation time of 800-1600ms. The proton exchange rate was about 10 3 s -1 , calculated from two-site exchange model. The proportion of β-glucan in the aggregate microphase increased from 0 to over 80% of the total β-glucan during storage of 112kDa samples. In the 4% solutions, the evolution of water proton relaxation associated with the gel network can be explained by the fractal structure theory. The relaxation behavior suggested the growth and syneresis of the gel network during the gelation of the low molecular weight β-glucan solutions., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Xanthan gum and carrageenan, representing the medium and highly negatively charged polysaccharides, were heated respectively together with soybean protein isolate (SPI) at different biopolymer ratios. Upon mixing with simulated stomach juice (SSJ), the xanthan-SPI and carrageenan-SPI at biopolymer ratios higher than 0.01 leads to self-assembled gelation immediately. Stronger gel is formed under higher biopolymer ratios. Highly negatively charged carrageenan forms a stronger gel than that composed with xanthan gum. SDS-PAGE results show the digestibility of SPI is delayed after incorporation with the polysaccharides, which is enhanced with the increase of the biopolymer mass ratios. And the polysaccharide with higher negative charge has stronger potential in delaying the digestion of SPI. Furthermore, the microstructure of the xanthan-SPI and carrageenan-SPI gel before and after simulated stomach digestion was characterized by scanning electron microscope (SEM), which also confirms that the gel delays the digestion of soybean protein., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Differential oxidative modifications of myofibrillar protein (MP) by hydroxyl radicals generated in an enzymatic system with glucose oxidase (GluOx) in the presence of glucose/FeSO 4 versus a Fenton system (H 2 O 2 /FeSO 4 ) were investigated. Pork MP was modified at 4 °C and pH 6.25 with hydroxyl radicals produced from 1 mg/mL glucose in the presence of 80, 160, or 320 μg/mL GluOx and 10 μM FeSO 4 . Total sulfhydryl content, solubility, cross-linking pattern, and gelation properties of MP were measured. H 2 O 2 production proceeded linearly with the concentration of GluOx and increased with reaction time. GluOx- and H 2 O 2 -dose-dependent protein polymerization, evidenced by faded myosin heavy chain and actin in SDS-PAGE as well as significant decreases in sulfhydryls, coincided with protein solubility loss. Firmer and more elastic MP gels were produced by GluOx than by the Fenton system at comparable H 2 O 2 levels due to an altered radical reaction pathway.

The aim of this study was to determine the influence of extraction pH on heat-induced aggregation, gelation and microstructure of suspensions of protein isolates extracted from quinoa (Chenopodium quinoa Willd). Quinoa seed protein was extracted by alkaline treatment at various pH values (pH 8 (E8), 9 (E9), 10 (E10) and 11 (E11)), followed by acid precipitation. The obtained protein isolates were freeze dried. The protein isolates E8 and E9 resulted in a lower protein yield as well as less protein denaturation. These isolates also had a higher protein purity, more protein bands at higher molecular weights, and a higher protein solubility in the pH range of 3-4.5, compared to the isolates E10 and E11. Heating the 10%w/w protein isolate suspensions E8 and E9 led to increased aggregation, and semi-solid gels with a dense microstructure were formed. The isolate suspensions E10 and E11, on the other hand, aggregated less, did not form self-supporting gels and had loose particle arrangements. We conclude that extraction pH plays an important role in determining the functionality of quinoa protein isolates., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Silk fibroin (SF) is a typical fibrous protein that is secreted by silkworms and spiders. It has been used in a variety of areas, and especially for tissue-engineering scaffolds, due to its sound processability, mechanical properties, biodegradability, and biocompatibility. With respect to gelation, the SF gelation time is long in aqueous solutions, so a novel approach is needed to shorten this time. The solubility of regenerated SF is sound in formic acid (FA), which is a carboxylic acid of the simplest structure. In this study, SF was dissolved in formic acid, and the addition of salts then induced a rapid gelation that accompanied a solution-color change. Based on the gelation behaviors of the SF solution according to different SF and salt concentrations, the gelation mechanism was investigated., Competing Interests: The authors declare no conflict of interest.

A sulfated polysaccharide extracted from Navicula sp. presented a yield of 4.4 (% w/w dry biomass basis). Analysis of the polysaccharide using gas chromatography showed that this polysaccharide contained glucose (29%), galactose (21%), rhamnose (10%), xylose (5%) and mannose (4%). This polysaccharide presented an average molecular weight of 107 kDa. Scanning electron microscopy (SEM) micrographs showed that the lyophilized Navicula sp. polysaccharide is an amorphous solid with particles of irregular shapes and sharp angles. The polysaccharide at 1% (w/v) solution in water formed gels in the presence of 0.4% (w/v) FeCl₃, showing elastic and viscous moduli of 1 and 0.7 Pa, respectively. SEM analysis performed on the lyophilized gel showed a compact pore structure, with a pore size of approximately 150 nm. Very few studies on the gelation of sulfated polysaccharides using trivalent ions exist in the literature, and, to the best of our knowledge, this study is the first to describe the gelation of sulfated polysaccharides extracted from Navicula sp.

Influence of high intensity ultrasound (HIUS) on the structure and properties of ovalbumin (OVA) were investigated. It was found that the subunits and secondary structure of OVA did not change significantly with HIUS treatment from the electrophoretic patterns and circular dichroism (CD) spectrum. The amount of free sulfhydryl groups increased and intrinsic fluorescence spectra analysis indicated changes in the tertiary structure and partial unfold of OVA after sonication increased. Compared with the untreated OVA, HIUS treatment increased the emulsifying activity and foaming ability, and decreased interface tension (oil-water and air-water interface), which due to the increased surface hydrophobicity and decreased the surface net charge in OVA, while the emulsifying and foaming stability had no remarkable differences. The increased particle size may be attributed to formation of protein aggregates. Moreover, the gelation temperatures of HIUS-treated samples were higher than the untreated OVA according to the temperature sweep model rheology, and this effect was consistent with the increased in surface hydrophobicity for ultrasound treated OVA. These changes in functional properties of OVA would promote its application in food industry., (Copyright © 2016 Elsevier B.V. All rights reserved.)