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This study prepared emulsion gels by modifying ovalbumin (OVA)-flaxseed oil (FSO) emulsions with transglutaminase (TGase) and investigated their properties, structure and oxidative stability under different enzyme reaction times. Here, we found prolonged reaction times led to the transformation of α-helix and β-turn into β-sheet and random coil. The elasticity, hardness and water retention of the emulsion gels increased significantly, but the water-holding capacity decreased when the reaction time exceeded 4 h. Confocal laser scanning microscope (CLSM) indicated extended enzyme reaction time fostered oil droplet aggregation with proteins. Emulsion gel reduced FSO oxidation, especially after 4 h of the enzyme reaction, the peroxide value (PV) of the emulsion gel was reduced by 29.16% compared to the control. In summary, the enzyme reaction time of 4 h resulted in the formation of a dense gel structure and enhanced oxidative stability. This study provides the potential applications in functional foods and biomedical fields., 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.)

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., 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.)

Ovotransferrin is the most heat-sensitive protein in egg white which alters the processing suitability. To improve thermostability, phosphorylation modification was performed under different pH values (5.0, 6.0, 7.0, 8.0, and 9.0), and the reasons for which were explored via physicochemical changes in this study. SEM and particle size results showed that phosphorylation diminished the average particle diameter and the number of attached particles. CD results revealed that the α-helix content of phosphorylated ovotransferrin increased and the random coil decreased significantly (P < 0.05). Tertiary structure, surface hydrophobicity and ζ-potential analyses showed that phosphorylation made more hydrophobic amino acids buried inside ovotransferrin. These changes might be because most of the phosphorylation occurred in α-helix and β- sheet to promote the thermal tolerance of phosphorylated ovotransferrin by improving its structure orderliness and decreasing surface hydrophobicity. The results indicated that phosphorylation was a practical method to enhance the thermal stability of heat-sensitive ovotransferrin., 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 © 2022 Elsevier Ltd. All rights reserved.)

Chitin is the most abundant natural amino polysaccharide, showing various practical applications owing to its functional properties. However, there are barriers in the development due to the difficulty of chitin extraction and purification, regarding its high crystallinity and low solubility. In recent years, some novel technologies such as microbial fermentation, ionic liquid, electrochemical extraction have emerged for the green extraction of chitin from new sources. Furthermore, nanotechnology, dissolution systems and chemical modification were applied to develop a variety of chitin-based biomaterials. Remarkably, chitin was used in delivering active ingredients and developing functional foods for weight loss, lipid reduction, gastrointestinal health, and anti-aging. Moreover, the application of chitin-based materials was expanded into medicine, energy and the environment. This review outlined the emerging extraction methods and processing routes of different chitin sources and advances in applying chitin-based materials. We aimed to provide some direction for the multi-disciplinary production and application of chitin., 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 © 2022 Elsevier Ltd. All rights reserved.)

In this paper, the effects of acylation modification on the gel behavior of ovalbumin (OVA) under heating induction have been investigated. From the obtained results, the acylated OVA hydrogels exhibited superior gelation properties than the native OVA hydrogels (NOVA-G) in terms of light transmission, gel hardness, resilience and water holding capacity. SEM revealed acylation modifications effectively promoted the formation of uniform and dense network structure of OVA hydrogels. The main intermolecular forces of the acylation-modified OVA hydrogels were hydrophobic interactions and hydrogen bonding. FTIR showed that acylation modifications caused 26.2% decrease in α-helix and 59.2% increase in β-sheet content compared to NOVA-G. Furthermore, in-vitro release experiments showed that the release rate of curcumin from acylated OVA hydrogels was significantly delayed. Moreover, the above results have shown that acylation modifications can be considered as an effective method to improve the gelation as well as drug release properties of protein hydrogels., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

In this study, we evaluated potential usage of acylated ovalbumin (AOVA) nanogels fabricated via acylation modification and heat-induced self-assembly process as novel delivery systems for curcumin. Compared to native ovalbumin (NOVA) nanogels without chemical acylation, the obtained AOVA nanogels have shown smaller average hydrodynamic diameter (155.73 nm), relatively uniform size distribution (polydispersity index around 0.28), enhanced negative surface charge (-24.3 mV), and an improved stability under the conditions of high ionic strength, different pH and storage time. Moreover, AOVA nanogels exhibited a remarkable conformational change in secondary and tertiary structures, improved surface hydrophobicity, and increased free sulfhydryl content compared with NOVA nanogels. Moreover, curcumin encapsulated in AOVA nanogels displayed higher encapsulation efficiency (93.64%) and slower sustained release under simulated gastrointestinal conditions as compared with NOVA nanogels. Hence, we have suggested that AOVA nanogels successfully fabricated with improved physicochemical properties as a novel ideal carrier for hydrophobic active compounds., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

This study aims to evaluate the effect of ultrasonic pretreatment combined with glycation on the structural characteristics and antibacterial activity of ovotransferrin (OVT). Firstly, OVT (purity >90%) was isolated from egg white with a simple and efficient method. After the treatment of ultrasound and glycation, the browning degree of OVT increased with the rising power of ultrasound, while the number of free amino groups obviously decreased to 25.4%. Various spectrum detection showed that the structures of OVT have changed significantly, indicating the tertiary structure became more flexible and looser. The minimal inhibitory concentration of ultrasound glycated OVT were 25.0 and 32.1 μmol/L for E. coli and S. aureus, respectively. In summary, ultrasound-assisted glycation is an effective technique to improve the biological activity of OVT., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this research, the impact of High Pressure Carbon Dioxide (HPCD) on the physicochemical, interfacial and rheological properties of liquid whole egg (LWE) was investigated. HPCD treatment increased the solubility, free sulfhydryl groups and surface hydrophobicity of LWE. The highest foaming ability (186%) and foaming stability (72%) were obtained at 60 min of HPCD treatment, which were 1.3-fold and 1.4-fold those of the control group (147% and 51%, respectively). Compared with the control group, the LWE emulsion had a minimum particle size (16.3 μm) when the treatment time was 75 min, and the highest absolute value of zeta potential reached 7.66 mV when the processing time was 60 min. HPCD treatment decreased the apparent viscosity of LWE at a low shear rate. Dynamic viscoelastic characteristics indicated that both the G' and G'' moduli of LWE under the HPCD process were lower than those of the control group at any frequency., 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.)

Chitosan-based macroparticle is a common carrier for enzyme immobilization applied in food industry. Driven by the requirement of large carrier pores for the biomacromolecular substrates such as protein, the eggshell membrane powder (ESMP) was employed as multifunctional porogen to improve the physicochemical structure of chitosan-based macroparticles. The prepared macroparticles were characterized by SEM, XRD, FTIR, Raman spectroscopy, nitrogen adsorption-desorption isotherms, and thermogravimetric analysis. The results showed that an increase of ESMP percentage could improve the porosity of macro holes in macroparticles, and it also enlarged the size of mesopores. Moreover, the ESMP significantly increased (P < 0.05) the amount of papain immobilization, whereas the specific activity of immobilized papain achieved a maximum value of 871.95 U/mg at CSESM2 and then declined with the increase of ESMP. Therefore, the inclusion of 20 % ESMP in chitosan-based macroparticles gave the highest activity of its immobilized protease., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this study, effects of nano-TiO 2 on the microstructural, physical, mechanical and optical properties of pullulan films were investigated. The results showed that the addition of nano-TiO 2 improved the water vapor barrier properties of the film due to the tortuous path formed by nano-TiO 2 . When the concentration of nano-TiO 2 was 0.04 g/100 mL, the tensile strength of the film showed a maximum value (15.99 MPa). The elongation at break of the film continued to decrease with the increase of nano-TiO 2. The TEM analysis showed that higher concentration of nano-TiO 2 would cause greater aggregation. Meanwhile, the results of FTIR and low-field NMR indicated that the miscibility between pullulan and nano-TiO 2 was due to the formation of intermolecular hydrogen bonds during film formation. Furthermore, the addition of nano-TiO 2 significantly improved the film barrier properties to ultraviolet light., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In this study, genipin and glutaraldehyde in varied concentrations were utilized in chitosan crosslinking under alkaline condition. A UV/Vis analysis was used to investigate the molecular structure of genipin and glutaraldehyde in an aqueous alkaline solution. The results showed the formation of glutaraldehyde dimer and polymerized genipin. The FTIR-ATR, SEM, DSC, XRD, mechanical properties, crosslinking degree and swelling ratio of chitosan based films crosslinked by genipin and glutaraldehyde were determined. The results indicated that the hydrogen bonds formed between genipin and chitosan enabled the films crosslinked by genipin (1 and 5 mmol/L) to have a higher degree of crosslinking, but a lower swelling ratio than glutaraldehyde (1 and 5 mmol/L). Genipin enabled the chitosan-based film to possess better mechanical properties and crystallinity than glutaraldehyde. The polymerization of genipin had a substantial effect on the network structure and swelling behavior of chitosan-based films crosslinked by genipin., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

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., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Chitosan based organic-inorganic composite films were prepared through direct incorporation of nanosilica particles in order to enhance their performance for potential packaging material. After the addition of nanosilica, the viscosity of film-forming solutions (FFSs) decreased obviously, and the G' of FFS with 25% of nanosilica was higher than that of other FFSs with nanosilica. In low field nuclear magnetic resonance (LF-NMR) determination, the addition of 25% of nanosilica gave rise to the lowest relaxation time and peak area proportion of T 21 component. Additionally, the changes of structure characteristic of composite films with different nanosilica content were analyzed through FTIR spectroscopy, SEM and XRD analysis. The thermal stability of films improved markedly with increasing nanosilica. The optimal mechanical properties of films were yielded at 25% of nanosilica. Furthermore, the introduction of nanosilica significantly (p < 0.05) decreased the swelling ratio of chitosan based films at pH 7.6 and pH 2.6., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

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., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In this paper, several new perspectives concerned with the effect of Tween 80 promoting pullulan production were presented. With the presence of Tween 80, the maximum pullulan yield increased by 41% (53.04 g/L). Meanwhile, the carbon source was consumed faster and the broth viscosity was higher. The lower final pH suggested that Tween 80 could protect the integrity of the mycelia. The dispersed filaments were not easily entangled with each other and less pellets were formed in the Tween 80 culture broth. FT-IR spectrum analysis indicated that the evaluated sample structure was coincided with commercial pullulan. The molecular weight of sample significantly dropped comparing with the control. The above findings indicated that Tween 80 facilitated the uptake of nutrient from surroundings to the microorganism and the release of pullulan into the extracellular fluid. These results were useful in better understanding the regulation and optimization of efficient pullulan fermentation., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

With the purpose of understanding the metabolic network of Aureobasidium pullulans, the central metabolic pathways were confirmed by the activities of the key enzymes involved in different pathways. The effect of different iodoacetic acid concentrations on pullulan fermentation was also investigated in this paper. The activities of phosphofructokinases and glucose-6-phosphate dehydrogenase existed in A. pullulans CGMCC1234, whereas 2-keto-3-deoxy-6-phosphogluconate aldolase activity was not detected. We proposed that the central metabolic pathways of A. pullulans CGMCC1234 included EMP and PPP, but no ED. Pullulan production declined fast as the iodoacetic acid increased, while cell growth offered upgrade firstly than descending latter tendency. Compared to the control group, the ratio of ATP/ADP of 0.60 mM iodoacetic acid group was lower at different stages of pullulan fermentation. The findings revealed that low concentration of iodoacetic acid might impel carbon flux flow toward the PPP, but reduce the flux of the EMP., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Fresh pork bacon belly was used as material and manufactured into dry-salted bacon through salting and drying-ripening. During processing both oxidative stability and antioxidant enzyme stability were evaluated by assessing peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and activities of catalase, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD), and their correlations were also analysed. The results showed that all antioxidant enzyme activities decreased (p<0.05) until the end of process; GSH-Px was the most unstable one followed by catalase. Antioxidant enzyme activities were negatively correlated with TBARS (p<0.05), but the correlations were decreased with increasing process temperature. Salt showed inhibitory effect on all antioxidant enzyme activities and was concentration dependent. These results indicated that when process temperature and salt content were low at the same time during dry-salted bacon processing, antioxidant enzymes could effectively control lipid oxidation., (Copyright © 2013 Elsevier Ltd. All rights reserved.)