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

Abstract

BACKGROUND 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. RESULTS 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. CONCLUSION 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

Physicochemical properties of acid‐soluble collagens from different tissues of large yellow croaker (Larimichthys crocea)

“…The hydrophobic and electrostatic interactions between collagen chains are involved in the self‐assembly into fibres (Zhang et al ., 2006). This might be attributed to the lower levels of cross‐linking in ASC from scales, as well as the less N‐H group involving into hydrogen bonding (Comper & Veis, 1977; Shi et al ., 2020). Moreover, the higher solubility of ASC from scales when the pH < 7.2 (Fig.…”

“…For example, the pI value of collagen from bigeye tuna skins is 6.1 (Ahmed et al ., 2019), and collagen from striped catfish skins has a pI of 4.27 (Singh et al ., 2011). The differences of pI in ASC from various tissues might be attributed to not only the proportion of acidic and alkali amino acids, but also the treatments during ASC preparation (Shi et al ., 2020). The surface charges of ASCs decreased when pH increased from 2.0 to 4.0.…”

Fabrication of Bacterial Cellulose Nanofibers/Soy Protein Isolate Colloidal Particles for the Stabilization of High Internal Phase Pickering Emulsions by Anti-solvent Precipitation and Their Application in the Delivery of Curcumin

“…The G′ of BCNs/SPI colloidal particles self-assembled by the anti-solvent precipitation was higher than that of the colloidal particles self-assembled by a simple complex method at the linear viscoelastic interval, suggesting that the colloidal particles self-assembled by the anti-solvent precipitation had stronger gel viscoelasticity. With an increase in stress, an obvious intersection (yield point) appeared, which indicated the changes of gel viscoelasticity, showing the conversion from gel-like behaviors to sol-like behaviors ( 47 ). The corresponding crossover point increased from 106 Pa for S-BCNs/SPI colloidal particles to 958 Pa for A-BCNs/SPI colloidal particles.…”

“…With an increase in stress, an obvious intersection (yield point) appeared, which indicated the changes of gel viscoelasticity, showing the conversion from gel-like behaviors to sol-like behaviors (47). The corresponding crossover point increased from 106 Pa for S-BCNs/SPI colloidal particles to 958 Pa for A-BCNs/SPI colloidal particles.…”

Effects of bioactive glass with high phosphorus content on mineralization of type I collagen fibrils

“…Different pH conditions affect the electric charge and collagen mineralization properties of self-assembled type I collagen fibrils [28,29]. Marelli et al found that type I collagen fibrils formed at pH 9.0 had greater electronegativity and induced faster collagen mineralization in SBF [28].…”