Endothermic Peak Temperature Research Articles

Insight into structural changes in heat-induced whey protein-fucoidan hydrogel by SR-IR and molecular docking techniques

This study aimed to investigate the structural changes in heat-induced polymerized whey protein (PWP)-fucoidan (FCN) hydrogels with different FCN concentration (0 % to 0.75 %, w/v). The interaction of PWP and FCN were traced by simultaneous rheology and Fourier transform infrared spectroscopy spectra (SR-IR) technology. The particle size and absolute zeta potential of PWP-FCN increased significantly (p < 0.05) with higher FCN concentrations, indicating that the formation of PWP-FCN enhanced the stability of the system. The gelation time of PWP-FCN was shortened from 1328 s to 881 s as the FCN concentration increased from 0 to 0.75 % (w/v) paralleled the increased apparent viscosity. The endothermic peak temperature of the hydrogels increased from 95.28 °C to 102.26 °C demonstrating the improved thermal stability due to FCN. The intrinsic fluorescence, surface hydrophobicity, and free thiol groups of PWP-FCN all indicated that FCN could interact with PWP through hydrophobic interactions, which changed the tertiary structure of PWP, and increased the density of PWP-FCN network. Cryogenic scanning electron microscopy (Cryo-SEM) and SEM images showed that the interactions between PWP and FCN resulted to rough and wrinkled microstructure of samples. Results of SR-IR and molecular docking assay both indicated that FCN could also interact with PWP through hydrogen bonds. In summary, FCN could promote the gelation process and the physicochemical properties of PWP-FCN hydrogel. Results of this study could provide theoretical basis for the application of protein–polysaccharide hydrogels in food field.

Preparation and Characterization of PVA/Chitosan-Based Hydrogels Enriched with Carbon Materials via the Freeze-Thaw Method

The freeze-thaw method successfully prepared polyvinyl alcohol (PVA)/chitosan (CS)-based hydrogels. This study evaluated the hydrogel’s physical and thermal properties with a compositional variation of activated carbon (AC) and reduced graphene oxide (rGO) in PVA/CS (PCS) hydrogel. Incorporating AC into the PCS hydrogel led to pore reduction, yielding a lower swelling degree in PCS/AC hydrogel than in PCS hydrogel. On the other hand, adding rGO had minimal impact on the shape and distribution of pores. However, rGO exhibited effective dispersion on the hydrogel surface, reducing the swelling degree of PCS/rGO hydrogel. The maximum swelling degree only showed an increase in PCS/AC 0.1%, attributed to the porous nature of AC, effectively binding water molecules while maintaining a relatively consistent pore size compared to PCS hydrogel. Incorporating AC and rGO into the PCS hydrogel enhanced thermal stability, which is evident from the increased residue and endothermic peak temperature compared to the hydrogel without AC and rGO. These findings suggest that the modification with AC and rGO can enhance the physical and thermal properties of PCS hydrogel.

Effect of Eu2O3@C composite catalyst on hydrogen storage performance of Mg96La3Ni alloy

This study successfully synthesized Eu2O3@C composite catalyst by an improved chemical blowing method. The Eu2O3 nanoparticles in this catalyst are highly dispersed within a porous carbon matrix, exhibiting a well-developed mesoporous structure, a large specific surface area, and a high density of defects. Eu2O3@C was mixed with the Mg96La3Ni alloy through ball milling, and the impact of varying amounts of Eu2O3@C on the hydrogen storage performance of Mg96La3Ni was comprehensively investigated. The results showed that Eu2O3@C markedly enhances the de/hydrogenation kinetics of Mg96La3Ni, with the most substantial impact noted at a Eu2O3@C content of 2 wt %. At 360 °C, 77.3 % of the maximum hydrogen capacity could be absorbed within 2 min, while only 1.4 min was required to release 3 % of hydrogen. Additionally, Eu2O3@C markedly decreased the dehydrogenation activation energy of the alloys to 106.3 kJ/mol and reduced the endothermic peak temperature to 347 °C, while leaving thermodynamic properties unaffected. The Mg96La3Ni–Eu2O3@C composite exhibits remarkable cyclic stability, retaining its hydrogen storage capacity throughout the cycling process. This study pioneers a novel strategy to elevate the performance of magnesium-based hydrogen storage materials.

Pseudo lamellae of Cu6Sn5 on the crystal facet of Sn in electrodeposited eutectic Sn-Cu lead-free solder

Eutectic Sn-Cu lead-free solder is developed using the pulse electrodeposition method from a citrate bath at different current densities like 0.1, 0.2, 0.4, and 0.5 A/cm2. The exact composition of all the deposits was confirmed through atomic absorption spectroscopy (AAS) analysis. The coating deposited at 0.2 A/cm2 constitutes 0.7 wt% of Cu which is similar to the eutectic Sn-Cu composition. Microstructural characterization was carried out with the help of a scanning electron microscope (SEM). Sn was the major constituent in all the deposits while a little amount of intermetallic i.e. Cu6Sn5 was present for the deposits at 0.1 and 0.2 A/ cm2. The energy dispersive spectroscopy (EDS) results showed traces of Cu6Sn5 in the deposits. The formation of Cu6Sn5 was also confirmed through X-ray diffraction (XRD). For the deposit at 0.2 A/cm2, the endothermic peak temperature in DSC is exactly the same as that of the melting point of Sn-Cu eutectic. This electrodeposited microstructure resembles the conventional eutectic Sn-Cu cast structure. The top view of the deposited Cu6Sn5 on the steps of Sn creates an illusion of lamellar structure. The effect of current density on the roughness was analyzed through AFM.

Effect of Amylopectin Content on Mechanical, Barrier and Thermal Properties of Plasticized Starch/Chitosan Films

Mechanical, barrier, and thermal properties of films based on blends of corn starch and chitosan plasticized with ethylene glycol, glycerol, and sorbitol were investigated. Starch amylopectin variation was explored, and contents of 100% and 73% were employed to blend with chitosan and polyols. The findings showed that high amylopectin content has a significant effect (p &lt; 0.05), resulting in films with lower tensile strength (TS) and reduced water vapor permeability (WVP). On the other hand, the incorporation of polyols showed a significantly high (p &lt; 0.05) elongation at break (EB) for films plasticized with glycerol and sorbitol at high amylopectin content. For chitosan/73% amylopectin film, the addition of plasticizers exhibited no significant difference (p &lt; 0.05) among the samples for TS and WVP results. The amylopectin content played no influence in the degradation stability of the films measured by thermogravimetry (TGA). However, amylopectin content influences the endothermic peak temperature observed by differential scanning calorimetry (DSC) analysis. A reduction of about 15 °C was noticed for the film prepared with high amylopectin content, a behavior correlated to its amorphous structure, capable of retaining more water than a crystalline region.

Thermal Reactivity of High-Density Hybrid Hexahydro-1,3,5-trinitro-1,3,5-triazine Crystals Prepared by a Microfluidic Crystallization Method.

In this paper, the two-dimensional (2D) high nitrogen triaminoguanidine-glyoxal polymer (TAGP) has been used to dope hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) crystals using a microfluidic crystallization method. A series of constraint TAGP-doped RDX crystals using a microfluidic mixer (so-called controlled qy-RDX) with higher bulk density and better thermal stability have been obtained as a result of the granulometric gradation. The crystal structure and thermal reactivity properties of qy-RDX are largely affected by the mixing speed of the solvent and antisolvent. In particular, the bulk density of qy-RDX could be slightly changed in the range from 1.78 to 1.85 g cm-3 as a result of varied mixing states. The obtained qy-RDX crystals have better thermal stability than pristine RDX, showing a higher exothermic peak temperature and an endothermic peak temperature with a higher heat release. Ea for thermal decomposition of controlled qy-RDX is 105.3 kJ mol-1, which is 20 kJ mol-1 lower than that of pure RDX. The controlled qy-RDX samples with lower Ea followed the random 2D nucleation and nucleus growth (A2) model, whereas controlled qy-RDX with higher Ea (122.8 and 122.7 kJ mol-1) following some complex model between A2 and the random chain scission (L2) model.

Effect of volume energy density on selective laser melting NiTi shape memory alloys: microstructural evolution, mechanical and functional properties

Equi-atomic NiTi shape memory alloy (SMA) samples were manufactured by selective laser melting (SLM) with different laser volume energy densities via synchronously varying laser power and scanning speed. The processing quality, phase transformation, and microstructural evolution were investigated to explore the mechanisms that are responsible for mechanical and functional properties. The results showed scattered micro-sized spherical gaseous defects inside the deposit. One-stage phase transformation occurred without intermediate R-phase transition, and the temperature of both endothermic and exothermic peaks was lower than that of the ingot. The microstructure initially grew along the building direction, but displayed different crystal orientations between coarse columnar grains and refined irregular sub-grains. The micro-hardness mapping revealed that homogenous anti-indentation properties were acquired independent of location variations. While the anisotropic behavior in tensile properties occurred due to the passive effect of columnar B2 austenitic grains, a synergistic effect of strength and plasticity was acquired primarily due to the combined effect of sub-grain refinement strengthening and transformation-induced plasticity. The pre-deformed NiTi samples recovered to their original shape when heated above its critical phase transition point. This work demonstrated that the crack-free NiTi SMA with exceptional comprehensive performances could be fabricated by SLM through the control of energy density.

Optimization of Pinhão Extract Encapsulation by Solid Dispersion and Application to Cookies as a Bioactive Ingredient

Pinhão residues have a wide range of bioactive compounds and encapsulation can be one of the alternatives to increase their bioavailability. Thus, this work aimed to apply pinhão extract, pure and encapsulated by solid dispersion, in the formulation of cookies as a bioactive ingredient. For that, pinhão extract was encapsulated in different biopolymers (sodium caseinate, gelatin, and gum arabic) and with different shear mechanisms (sonication, Ultra-Turrax, and magnetic stirring). The best encapsulation procedure has been defined by a chemometric analysis (hierarchical cluster analysis), considering thermal properties (DSC) of particles and ( +)-catechin encapsulation efficiency (HPLC). The optimized conditions were gelatin as encapsulation agent and Ultra-Turrax as shear mechanism (70.1 ± 2.8 °C maximum endothermic peak temperature and 96.0 ± 2.3% ( +)-catechin encapsulation efficiency). The phenolic profile of the encapsulated extract showed the presence of ( +)-catechin (0.31 ± 0.01 (mg/gparticle), protocatechuic acid (0.29 ± 0.00 mg/gparticle), and ( −)-epicatechin (0.11 ± 0.00 mg/gparticle). Both the pure and encapsulated extracts were incorporated into the cookie formulation, which was characterized in terms of centesimal composition, color parameters, texture, and sensory aspects. It was found that cookies with the pure and the encapsulated extract showed significant differences concerning the centesimal composition, products added with pinhão extract and encapsulated extract presented higher values when compared to the control, probably influenced by the mineral content of the pinhão. In addition, higher hardness values were detected for cookies formulated with the encapsulated extract, which possibly negatively affected the consumer’s sensory perception.

Electrospun Fibrous Membrane with Confined Chain Configuration: Dynamic Relaxation and Glass Transition.

Thermodynamic glass transition processes of electrospun membranes were first introduced to study their dynamic relaxation nature, which is not constantly in equilibrium. The relaxation modes of electrospun membranes are slow but measurable near and above the Tg, given the stretched chain over long distances. Based on differential scanning calorimetry (DSC) experiments and the general principle of mode-coupling theory (MCT), endothermic peak temperature and relaxation enthalpy were used to analyze the relaxation process by capturing these instantaneous “arrested” structures. The short- and long-wavelength relaxation modes could be identified with different annealing times and temperatures relative to DSC-measured Tg for electrospun membranes with different molecular weights. Results clearly showed the dynamic nature of a glass transition in polymeric materials. Tp and enthalpy loss initially increased and then directly decreased with the increase in annealing time. When Ta > Tg, regardless of the size of the molecular weight, the Tp and enthalpy loss of the PLGA fibers would directly decrease, and the curves would shift toward the melted one. Combination of electrospinningand normal DSC instrument can be used to investigating the dynamic relax process through an adequately designed kinetic scanning procedure. This result can be explained by the general principle of MCT-type dynamic theory.

Physicochemical properties of films produced using nanoemulsions stabilized by carboxymethyl chitosan-peptide conjugates and application in blueberry preservation

Carboxymethyl chitosan (CMCh)-peptide conjugates were produced by grafting CMCh with peptides from hemp seed, maize and casein. The nanoemulsions stabilized by these conjugates had smaller droplet size and better emulsifying properties. Nanoemulsions stabilized by conjugates were used to develop active films containing Camellia essential oil and the effect of conjugation on physicochemical properties of resulting films was evaluated. Water vapor and oxygen barrier properties, tensile strength, flexibility, and temperature of endothermic peak increased 6.6–19.8% and 6.9–27.2%, 40.1–96.6%, 61.4–83.3% and 7.8–18.5%, respectively when the CMCh-peptide conjugates were used to emulsify the essential oil. The conjugation helped to form compact structure. All of the films containing essential oil emulsions stabilized by conjugates showed the ability to extend the shelf-life of blueberry by maintaining the firmness, reducing the weight loss and slowing down the formation of soluble solids.

Surface modified-gadolinium/boron/polyethylene composite with high shielding performance for neutron and gamma-ray

A series of surface modified-gadolinium/boron/polyethylene composites composed of surface modified fillers (M−microGd2O3 and M−nanoGd2O3) are prepared for shielding neutron and gamma radiation. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray energy spectrometer (EDS) reveal that the surface modification of fillers significantly improved the interfacial compatibility and dispersion in the polyethylene matrix. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and mechanical tensile tests show that the modification of nanoGd2O3 and microGd2O3 improve the thermal stability and mechanical property of the composites. The T5% (initial decomposition temperature), Tp (endothermic peak temperatures) and Tensile strength of 10wt% M-nanoGd2O3/20wt% B4C/70wt% HDPE reachs 463.5℃,137.2℃, and 19.6MPa, which is greatly improved compared with unmodified materials and neat HDPE. The neutron and gamma shielding mechanism of the composites is studied both by experimental measurements and Monte Carlo simulation. The results show that the improved interfacial compatibility and dispersion of fillers in the polyethylene matrix effectively enhances the neutron and gamma shielding rate. The shielding performance of the composite blended with M−nanoGd2O3 is significantly better than that of the composite blended with M−microGd2O3 and the unmodified materials with the relatively thin thickness. Finally, a superior composite containing 10 wt% M−nanoGd2O3/20 wt% B4C/70 wt% HDPE reaches a neutron shielding rate of 90% at 9.1 cm under Cf-252 environment, and a gamma shielding rate of 70% at 13.7 cm under Cs-137 environment, which have the characteristics of lead free, low specific gravity and high shielding performance and is expected to be a promising radiation shielding materials used in neutron-gamma mixed fields.

Silk Powder from Cocoons and Woven Fabric as a Potential Bio-Modifier.

Silk, as a protein fiber characterized by high biocompatibility, biodegradability, and low toxicity, is mainly used as textile structures for various purposes, including for biological applications. The key issue for unlimited silk applicability as a modifier is to prepare its relevant form to cover or introduce to other materials. This study presents silk powder fabrication from Bombyx mori cocoons and non-dyed silk woven fabric through cryogenic milling. The cocoons were milled before and after the degumming process to obtain powders from raw structures and pure fibroin. The powder morphology and composition were analyzed using scanning electron microscopy and energy dispersive spectroscopy. The influence of the milling on the silk structure was studied using infrared and Raman spectroscopies, indicating that silk powders retained dominant β-sheet structure. The powders were also analyzed by differential scanning calorimetry and thermogravimetric techniques. The thermal endothermic peak and onset temperature characteristic for silk decomposition shifted to the lower values for all powders, indicating less thermal stability. However, the process was found to be an efficient way to obtain silk powders. The new milled form of silk can allow its introduction into different matrices or form coatings without using any harsh solvents, enriching them with new features and make more biologically friendly.

Hydration Patterns in Sodium Alginate Polymeric Matrix Tablets-The Result of Drug Substance Incorporation.

The purpose was to show, using destructive/nondestructive methods, that the interplay between water, tablet structure, and composition determine the unique spatiotemporal hydration pattern of polymer-based matrices. The tablets containing a 1:1 w/w mixture of sodium alginate with salicylic acid (ALG/SA) or sodium salicylate (ALG/SNA) were studied using Karl Fischer titration, differential scanning calorimetry, X-ray microtomography, and magnetic resonance imaging. As the principal results, matrix specific features were detected, e.g., “locking” of the internal part of the matrix (ALG/SA); existence of lamellar region associated with detection of free/freezing water (ALG/SA); existence of water penetrating the matrix forming specific region preceding infiltration layer (ALG/SNA); switch in the onset temperature of endothermic water peak associated with an increase in the fraction of non-freezing water weight per dry matrix weight in the infiltration layer (ALG/SNA). The existence of complicated spatiotemporal hydration patterns influenced by matrix composition and molecular properties of constituents has been demonstrated.

Fabrication and characterization of bioactive nanoemulsion-based delivery systems

In this work, a nanoemulsion-based delivery system was developed by encapsulation of different concentrations (0.50%, 0.75% and 1.00% v/v) of oregano essential oil (OEO) within poly(vinyl alcohol). The delivery systems (OEO-loaded nanoemulsion systems (NESs)) were characterized in terms of size distribution, zeta potential and thermal, molecular, microstructural and antifungal properties. The average droplet diameter values were determined to be within the range 70–75 nm, while zeta potential values within the range 3.13–19.90 mV were recorded. An increase in the OEO concentration did not affect the size distribution of nanoemulsions. Change in the concentrations showed no visible differences in Fourier transform infrared spectra. However, for concentrations of 0.50, 0.75 and 1.00%, endothermic peak temperatures were recorded as 94, 105 and 117°C, respectively. The antifungal activity of NESs against the mycelial growth of Aspergillus niger was evaluated, revealing a significant enhancement in the antifungal activity in comparison with that of free OEO. The zone diameter of mycelial growth could be reduced by around 20, 55 and 65% using NESs at levels of 0.50, 0.75 and 1.00% v/v, respectively, over 6 days of incubation. The results of this study revealed the stronger antifungal efficiency of OEO by its encapsulation into NESs as compared with that of free OEO.

Characterization of magnesium-calcium oxysulfate cement prepared by replacing MgSO4 in magnesium oxysulfate cement with untreated desulfurization gypsum

A new magnesium-calcium oxysulfate cement (MCOSC) was proposed by replacing MgSO4 in magnesium oxysulfate cement (MOSC) with untreated flue gas desulfurization gypsum (FGDG) at levels of 25%, 50%, 75% and 100%. The synergistic effect of FGDG and chemical additives, including citric acid, ammonium citrate tribasic and ammonium dihydrogen phosphate on the mechanical performance and hydration mechanism of MCOSC was investigated. The results showed that three additives all promoted the formation of 5 Mg(OH)2·MgSO4·7H2O (5·1·7) phase and hindered Mg(OH)2 precipitation, improving mechanical properties of MCOSC. FGDG incorporation induced no new crystalline phase, but gypsum crystal provided the space for nucleation of 5·1·7 phase. FGDG also reacted with MOSC to form amorphous phase, which was identified as a magnesium-sulfide-calcium-hydrate gel. Moreover, it affected the morphology of 5·1·7 phase and lowered the temperature of endothermic peaks in the paste during the heating process. The additive-incorporated specimens with 25% FGDG replacement presented a superior compressive strength, water resistance and volume stability. This confirmed the effective application of FGDG in preparing MCOSC, and it also provided an approach for recycling waste gypsum.

Fabrication, characterization and emulsifying properties of potato starch/soy protein complexes in acidic conditions

Starch and proteins can be assembled into binary complexes with functional attributes that combine the desirable facets of each individual component. In this study, the formation of gelatinized potato starch (GPS)/soy protein (SP) complexes was investigated by turbidimetric analysis in acidic conditions. The optimum conditions for complexation included a pH of 3.5 and a GPS/SP mixed ratio of 4:1 (w/w). Differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were used to characterize the formed complexes. DSC data revealed that the endothermic peak temperature of gelatinized potato starch was increased due to the interaction between these two polymers. FTIR analysis showed that the complexes were mainly formed between the phosphate group of GPS and the amino groups of SPs. XRD results indicated that new structures were formed through electrostatic attraction. Moreover, the stability of emulsions stabilized by GPS/SP complexes at acidic pH were evaluated. We found that GPS/SP complexes formed at pH values lower than 3.0 displayed better emulsifying stability. Findings from this study will help in understanding the nature of interactions between potato starch and soy proteins and so as to design new food materials for nutraceutical and biomaterial applications.

Physicochemical and biological activities of polysaccharides from the waste residue of sea cucumber peptide production

This study was to investigate the physicochemical and biological activities of sea cucumber polysaccharides extracted from waste residue of peptide production (SCRP). The monosaccharide composition of SCRP was 20.03% mannose, 19.56% glucose, 18.63% galactose, 25.94% arabinose and 15.82% fucose with the Mw and Mn of SCRP of 57.5 and 51.3 kDa. The intrinsic viscosity of SCRP was 8.9 mL/mg with a liquid-like rheological behaviour. Two main endothermic peak temperatures of the SCRP sample were 85.03 and 231.80°C. SCRP rendered the early apoptosis of cells, as well as induced the loss of mitochondrial transmembrane potential and increase the reactive oxygen species (ROS) level with a concentration-dependence manner. The results implied that a by-product SCRP could be extracted from the waste residue during peptide production, and exhibited inhibitory effects against MDA-MB-231 cells.

High molecular weight chitosan based particles for insulin encapsulation obtained via nanospray technology

The objective of this work was to obtain Chitosan (CS) based particles for Insulin (INS) encapsulation, via nanospray drying of a feeding solution containing equal amounts of both components (0.1% w/v total solids content). The process was performed at pH 3 which is out of the range for electrostatic interactions to occur. The analysis involved the nanoparticles (NP) characterization in the solution before drying (pH 3) by dynamic light scattering (DLS) and after re-hydration at different pHs (3< pH < 11). The dried product was characterized by Fourier-transform spectroscopy (FTIR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). FTIR allowed detecting the chemical groups involved in INS-CS interactions. The encapsulation efficiency of the glassy NP was 62.3 ± 0.32% as determined by HPLC. Upon powder re-hydration, NP of diameter <200 nm were obtained, with a minority of them exceeding the micron. The change in the shape and temperature of the main endothermic DSC peak and the higher T g value of the NP would confirm the increase in INS thermal stability when entrapped in a CS matrix. In terms of biological activity an in-vitro system was assayed. 3T3-L1 fibroblasts were exposed to INS and Insulin-Chitosan nanoparticles (INS-CS NP). Both treatments showed AKT phosphorylation, which is an indication of AKT activation. The activity of AKT plays an essential role in cell metabolism (lipid and glucose), growth, proliferation, polarity, among others. This activity is a measure of the upstream cell signals, i.e. INS’s receptor activity. Phosphorylated AKT was detected during the assay time for INS-CS NP, showing remarkable differences respect to single INS. Nanodrying technology could be used to trap INS into CS matrix keeping the specific hormone functions and protecting it from the hostile conditions of the body.

Araucaria angustifolia seeds drying behaviour, flour and starch properties

A. angustifolia seeds processing allows to extend its offer period. This research had the aim to study differences between fresh and frozen raw seeds drying characteristics, establish the flour microbiological, the starch granule morphologic and pasting properties. The methodology used was laboratory research. The starch was extracted and determined the amylose content, the granules were examined by SEM, the pasting properties by RVA and the thermal behaviour by DSC. The frozen seeds presented higher drying rate, however from the critical moisture, they had similar intern resistance. The starch yield was 19.5% and its amylose content was 12.9%. Through SEM was identified smooth granules without erosion, thus oval and rounded shape. The viscosity pattern corresponds to a matrix with tendency to retrogradation. The starch initial pasting temperature, endothermic peak temperature, complete gelatinization temperature and enthalpy of gelatinization found were, 53.34, 60.32, 67.25 and 2.58 J/g.

Effect of pH on properties of golden pompano skin collagen-based fibril gels by self-assembly in vitro.

Application of fish skin collagen has received increasing attention due to mammalian derived diseases and religious limitations. Collagen fibril gel could be formed in vitro through the self-assembly process. The present study investigated the effect of pH on the self-assembly in vitro of acid-solubilized collagen (ASC) from golden pompano skin by determining the turbidity, rheological viscoelasticity, network structure, gel strength, and thermal stability of collagen fibril gel. The isoelectric point of ASC was pH 5.27. The turbidity-time and rheological viscoelasticity results indicate that the collagen self-assembly rate in vitro at pH 7.0 was the slowest. The rate was accelerated by increasing or decreasing the pH. Scanning electron microscopy images show that the fibril diameters of the collagen fibril gels and the collagenous fibril number in the collagen fiber increased with the pH. The gel strength of the collagen fibril gel prepared at pH 5.0 was 22.06 g and increased up to 220.46 g when pH increased to 8.0. No obvious peaks were observed in the differential scanning calorimetry curves of the collagen fibril gels prepared at pH 5.0, whereas high endothermic peak temperature (Tm ) and enthalpy change (ΔH) were found in the collagen fibril gels prepared at pH 6.0-8.0. It is concluded that the physical properties of ASC fibril gels can be improved by increasing the fibril diameter controlled by pH. © 2020 Society of Chemical Industry.