Shuaishuai Wei,Jiaying Huo,Jia Lin,Ziwei Zhang,Shijian Dong,Lulu Ma,Shugang Li
Summary In this study, a method to produce iron-chelating peptides derived from egg yolk proteins was developed and optimised. The egg yolk proteins were enzymolysed and ultrafiltered to prepare egg yolk peptide (EYP), and then the EYP was chelated with Fe to produce egg yolk peptide-Fe (EYP-Fe). The optimised mass ratio of peptide to iron, pH, temperature and reaction time were found at 8:1, pH 8.0, 40 °C and 30 min, respectively. The mean particle size of EYP-Fe was 389.2 ± 2.61 nm, and the chelating ratio was 95.38 ± 1.93%. The measurements of FTIR, X-ray photoelectron spectroscopy (XPS) and NMR showed that ferrous ions mainly combined with the amino and carboxyl of EYP to form EYP-Fe. In vitro stability studies have shown that the iron release rate of the EYP-Fe is maintained at around 5% under alkaline conditions, and there is no significant difference in iron release rate under conditions of 30 °C–80 °C; besides, it has a lower iron release rate (18%) in gastrointestinal digestion compared to FeSO 4 (97.93%), indicating that the EYP-Fe has good heat tolerance, alkalinity and digestion tolerance. The above results provide a scientific basis for the use of EYP-Fe derived from egg yolk protein as a potential alternative to iron supplements.
The efficient recovery of germanium from complex secondary resources is a significant challenge in resource sustainability. In this study, a tartaric acid-functionalized nitrogen-doped hydrochar (NPB-TA) was synthesized for selective germanium (Ge) capture from aqueous solutions containing other metal ions. Adsorption experiments demonstrated that NPB-TA can be used in germanium solutions of varying pH and concentration, achieving a saturated adsorption capacity of 112.23 mg/g at pH = 3. The adsorption process was found to be in accordance with the Langmuir isotherm and pseudo-second-order kinetic models, indicating monolayer adsorption and chemisorption as the dominant mechanisms. Moreover, NPB-TA exhibited superior selectivity toward Ge (IV) even in binary systems with competing ions. Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Density functional theory calculations were applied to elucidate the adsorption mechanism. The mechanism involves synergistic coordination between Ge (IV) and surface-bound -OH/-COOH groups, with amino groups facilitating the formation of stable chelating rings containing C-O-Ge/C-N-Ge bonds. This study demonstrates that tartaric acid-modified N-doped biosorbent has potential for the selective recovery of germanium from aqueous solution.
This study aimed to separate and identify novel zinc-chelating peptides from soybean protein hydrolysate obtained by trypsin, and investigate the mechanism of soybean peptide chelating zinc ion. The fraction F323, possessing strong zinc-chelating ability with a chelation rate of 87.19 % ± 0.91 %, was separated by ultrafiltration, gel filtration chromatography and anion-exchange chromatography. Six identified peptides were selected and predicted to be negatively charged and have good water solubility. All these peptides showed zinc-chelating activity, among which EEGQQQGEQR, VFDGELQEGR, and EEQEWPR exhibited the highest zinc-chelating capacity. EEGQQQGEQR tended to form a more ordered structure after chelating zinc ions. FTIR spectra showed that amide groups and carboxyl groups in the three peptides were likely involved in the chelation. Molecular dynamics simulation results revealed that the amino acid residues in soybean peptides participating in the chelation of zinc ion were mainly glutamic acid (Glu, E), then aspartic acid (Asp, D) and glutamine (Gln, Q). The carboxyl oxygens in the side chain groups of Glu(E) and Asp(D), and the carbonyl oxygen of peptide bond were involved in the coordination with zinc ion. These results provide theoretical foundations for the preparation of zinc-chelating peptides from soybean protein, and the development of peptide-zinc chelates used as zinc supplements.
危险品化学品经营许可证（带存储）