Search

Abstract Egg white protein was phosphorylated with microwave assistance (200 W, 300 W, 400 W, 500 W and 600 W) in the presence of sodium tripolyphosphate at pH 8.0, and the structural and foaming properties of the protein were investigated in this work. The degree of phosphorylation increased at first and then remained unchanged. Fourier Transform infrared spectroscopy showed that egg white had new characteristic absorption bands by phosphorylation. Circular dichroism spectroscopy and surface hydrophobicity analysis revealed that the phosphorylated proteins had a more unfolded and flexible structure. The phosphorylated proteins had higher absolute values of zeta potential and a lower content of free -SH. After treatment with microwave at the 500 W level, phosphorylated protein had a 0.44 times (P < 0.05) greater foaming ability and 1.1 times (P < 0.05) greater foaming stability compared with the untreated sample. The results suggested that microwave-assisted phosphorylation modification is a practical method to improve egg white protein foaming properties. Highlights • Microwave-assisted technique speeds up the phosphorylation modification reaction. • CD and H o results reveal that PP-EWP molecule becomes more unfolded and flexible. • Phosphorylation with microwave-assisted change secondary structure of EWP. • FA and FS of 500W-PP-EWP increased by 44.2% and 107.2%, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • SEW improved the texture properties of steamed bread. • SEW is utilised as a sustainable ingredient in steamed bread formulations. • Micromorphology showed a compact and smooth structure after adding SEW. • Enrichment of steamed bread with 15% SEW shows significant acceptability. Steamed bread has long been an important part of Chinese cuisine. This study investigated the effects of salted egg white (SEW) (5, 10, 15, and 20% w/w) on the quality of steamed breads. Findings revealed that SEW notably enhanced the bread's volume and texture, with a 20% inclusion significantly boosting water retention and rheological properties, albeit reducing bread's lightness. In addition, the H-bond absorption band intensity in the Fourier transform infrared spectroscopy (FTIR) analysis showed increased peak intensities with higher SEW levels, indicative of protein structure alterations. X-ray diffraction confirmed the presence of an amylose–lipid complex. Scanning electron microscope (SEM) and Confocal laser scanning microscope (CLSM) imaging depicted a smooth, consistent protein network with SEW addition. Consumer sensory evaluation responded favourably to the SEW15 steamed bread, suggesting its potential for food industry application. Overall, the study considers SEW an effective ingredient for improving steamed bread quality. [ABSTRACT FROM AUTHOR]

Highlights • Alcalase and neutrase were used for preparing calcium-binding peptide from pig bone. • The chelating conditions was optimized by response surface methodology. • The differences of characterization between peptide and peptide-calcium chelate were given. • The stability of chelate against to pH, temperature and gastrointestinal digestion was evaluated. • Peptide-calcium chelate could significantly improve calcium transport in Caco-2 cell monolayer. Abstract In this study, alcalase and neutrase were used in combination to prepare collagen peptides with high calcium binding ability. The optimal conditions for the preparation of peptide-calcium chelate (mass ratio of peptide/calcium of 4.5:1 for 40 min at 50 °C and pH 9) were determined by response surface methodology (RSM), under which a calcium chelating rate of 78.38% was obtained. The results of Ultraviolet–Visible (UV–Vis), fluorescence and Fourier transform infrared (FT-IR) spectra synthetically indicated that calcium could be chelated by carboxyl oxygen and amino nitrogen atoms of collagen peptides, thus forming peptide-calcium chelate. The chelate was stable at various temperatures and pH values, and exhibited excellent stability in the gastrointestinal environment, which could promote calcium absorption in human gastrointestinal tract. Moreover, Caco-2 cell monolayer model was used to investigate the effect of peptide-calcium chelate on promoting calcium absorption. Results showed that peptide-calcium chelate could significantly improve calcium transport in Caco-2 cell monolayer and reverse the inhibition of calcium absorption by phosphate and phytate. The findings provide a scientific basis for developing new calcium supplements and the high-value utilization of pig bone. [ABSTRACT FROM AUTHOR]

Herein, we proposed an interconnected-porous chitosan macroparticles (IPCMs) immobilized papain to exactly control the enzymatic hydrolysis degree of egg white (EW) via a non-heating technology in order to improve its foamability. The SEM images showed that the sodium carbonate (Na 2 CO 3) as gas porogen with varying concentration was able to improve the porosity structure of surface layer of interconnected-porous chitosan macroparticles (IPCMs). The activity determination results indicated that the IPCMs prepared with 0.4 M Na 2 CO 3 hold the highest activity immobilized of papain. In comparison with free enzyme, immobilized papain had a higher range of pH and temperature adaptability, as well as the thermal stability. With a limited hydrolysis, the immobilized papain obtained through condition optimization could enhance the foaming capability (FC) and foaming stability (FS) of EW to 646.67% and 71.62%, respectively. The Fourier transform infrared spectroscopy (FTIR), particle size, zeta potential and surface hydrophobicity were used to analyze the molecular structure change of EW after hydrolysis. Importantly, the immobilized papain could control the enzymatic reaction processing via simple separation, ensuring the optimal hydrolysis degree of EW for foamability enhancement, it also prevented the decrease in foamability during storage due to continuous enzymatic hydrolysis. [Display omitted] • Na 2 CO 3 can improve the porosity structure of the surface layer of IPCMs. • The IPCM-immobilized papain possesses a great stability to environment. • The IPCM-immobilized papain can achieve the controllable hydrolysis of egg white. • Foamability of egg white is improved about 2 folds by controlled hydrolysis. • Improved foamability via IPCM-immobilized papain will not decrease during storage. [ABSTRACT FROM AUTHOR]

The present study investigated the effect of different irradiation dose (0, 3, 5 and 7 kGy) on the emulsifying properties development of pork myofibrillar protein (MP) and sacroplasmic protein (SP). The results showed that emulsifying activities of SP was significantly impaired by the increasing irradiation dose, while that of MP were only observed to be significantly improved at 3 kGy irradiation ( P  < .05). The increasing irradiation dose caused the increase of SP carbonyl groups and the decrease of its sulfhydryl groups ( P  < .05), while 3 kGy irradiation decreased the carbonyl groups of MP and increased ζ-potential significantly ( P  < .05). LF-NMR results revealed that the water hydration in MP structure was dose-dependent. FT-IR data displayed that irradiation caused minor change of SP in the amide I region from 1700 to 1600 cm −1 , while ≥5 kGy irradiation significantly contributed to the denatured aggregated β-sheet components of MP. [ABSTRACT FROM AUTHOR]

Poor rehydration is one of the limiting factors affecting the processing and functional properties of egg white powder (EWP). In order to improve rehydration, this study explored the ultrasound-assisted deamidation method (ultrasound power: 100 W, 200 W, 300 W, 400 W and 500 W) and its effects on the physicochemistry and processing properties of EWP. The degree of deamidation increased at first and then decreased with the increase of ultrasound power. After deamidation, rehydration significantly increased. SDS-PAGE results showed that glutaminase had no obvious effect on protein composition. However, circular dichroism spectroscopy, Fourier transform infrared spectroscopy and surface hydrophobicity analyses showed that deamidation contributed to the decrease in α-helix and increase in random coil structure, which generated more flexible and stretchable conformational proteins. The average particle size and ζ-potential of EWP changed significantly, indicating that ultrasound-assisted deamidation treatment caused the de-aggregation and re-aggregation of EWP. These helped to promote the wettability, solubility and dispersion and reduce the turbidity of the rehydrated solution by altering the surface hydrophobicity and increasing the flexibility of EWP molecules. Best rehydration was observed in the sample of 300 W-EWP. These results suggested that ultrasound-assisted deamidation treatment is a practical method to enhance the processability and applicability of EWP. [Display omitted] • Deamidation treatment enhanced thermal stability of egg white powder. • Deamidation treatment made egg white particles more porous and looser. • The structure of deamidated egg white proteins became more flexible and stretchable. • Ultrasound-assisted deamidation treatment is a practical method to improve rehydration of EWP. [ABSTRACT FROM AUTHOR]

Phosvitin has a similar structure and similar properties to the phosphorylated proteins that play an important role in biomineralization, suggesting that phosvitin may have similar regulation properties. This study investigated the effect of phosvitin on regulating the phase transformation of the mineral calcium phosphate in a biomimetic mineralization solution; the characterization techniques used were Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and fluorescence spectroscopy. The results clearly demonstrated that phosvitin significantly promotes the initiation of phase transformation, accelerated the transformation process and shortened the transformation time from 6 to 0.5 h. Phosvitin was involved in the phase transformation and incorporated into or strongly absorbed on the mineral, as evidenced by the protein peaks observed in the FTIR spectra and XRD patterns. The effects of the substrate-addition sequence on the phase transformation demonstrated that the phosvitin-Ca 2+ interaction played a key role in the regulation of mineralization. Compared with those for BSA, the results revealed that the role of phosvitin in mineralization is closely associated with its high level of phosphorylation. This study provides useful information about using phosvitin as a potential candidate for biomaterials. [ABSTRACT FROM AUTHOR]