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This study was conducted to investigate the effects of different copper salts on the physicochemical properties, microstructure and intermolecular interactions of preserved egg white (PEW) during pickling. With increased pickling time, the alkalinity of the pickling solution and the moisture of PEW pickled by three copper salts (CuSO

This study was conducted to investigate the dynamic regulation of alkali infiltration by different metal compounds during the pickling of preserved eggs. With the increased pickling time, the alkalinity of the pickling solution decreased, while the pH of preserved egg white increased firstly, then decreased, and finally increased again. The metal ions corresponding to the added metal compounds (CuSO

In this study, we aimed to investigate the changes in gelation behavior of raw (without heating) and cooked (with heating) salted egg yolks during pickling. Results indicated that the decreasing trend in the main peak T22 of raw and cooked salted egg yolks. Cooked salted egg yolks after 28 days of pickling had a higher release of free lipids as visualized using a confocal laser scanning microscope (CLSM). Transmission electron microscope (TEM) micrographs showed that protein granules were distributed together with lipid spheres in raw and cooked salted egg yolks, and the liberated constituents (lipids and proteins) reorganize and aggregate in cooked salted egg yolks after 28 days of pickling. As the pickling proceeded, the soluble protein content and free sulfhydryl content of raw salted egg yolks, the free sulfhydryl content and surface hydrophobicity of cooked salted egg yolks showed an overall increasing trend, followed by significant decrease. The surface hydrophobicity of raw salted egg yolks exhibited an increasing trend. Differential scanning calorimetry (DSC) results demonstrated that salting can stabilize the protein molecules by an increase in denaturation temperatures. Fourier transform infrared spectroscopy (FTIR) revealed that the secondary structures of egg yolk proteins underwent changes, but no difference in protein patterns of either raw or cooked salted egg yolks was observed by SDS–PAGE during pickling. These results suggested that the characteristic gel of salted egg yolks is formed, as the result of multiple interactions between protein molecules and between protein and lipid molecules.

To improve the foaming properties of egg white powder (EWP), the effects of incorporating four different kinds of peptides (soy peptides, corn peptides, whey peptides, and fish skin peptides) were evaluated. The addition of soy peptides (SP) enhanced the foamability, foam stability, and solubility of EWP, whereas whey peptides (WP) significantly reduced the foam stability and solubility. Adding corn peptides (CP) and fish skin peptides (FP) notably improved the foaming properties but had no significant effect on solubility. The addition of SP, WP, and CP markedly reduced zeta potential and surface tension and increased surface hydrophobicity. The rheology data showed that adding SP, CP, and FP significantly increased the elastic modulus of the foam, yet WP notably reduced the elastic modulus. The results obtained by Fourier infrared spectroscopy indicated that the addition of the four kinds of peptides made the secondary structure of egg white protein more flexible. In short, SP, CP, and FP could improve the foaming performance of EWP.

The poor emulsifying property of Ovalbumin (OVA) greatly restricted the overall development of eggs in the food industries. In this paper, we investigated the effects of different xanthan gum (XG) concentrations and different pH value on OVA-stabilized oil-in-water emulsions. From the results of turbidity, ultraviolet absorption spectra and fluorescence spectra, we could find that OVA and XG had an obvious interaction. With increasing XG concentration (0–0.4%), the particle size of OVA-XG complex-stabilized emulsions gradually decreased and absolute value of zeta potential significantly increased. The storage stability of the emulsions was obviously improved by increasing the amount of XG. The apparent viscosity of complex-stabilized emulsions significantly increased, thereby improving the emulsions stability. In addition, our results confirmed emulsions stability largely depended on the pH value. OVA-XG composite emulsion showed a better stability at pH 5.5. Our findings indicated that XG had the potential as an emulsions stabilizer and could be used in egg white-derived foods.

Ethnopharmacological relevance Egg yolk oils (EYO) is a traditional Chinese medicine obtained from Gallus gallus domesticus Brisson, which has been used to treat inflammatory related diseases such as cheilitis, ulceration and acute anal fissure. However, the detailed anti-inflammatory mechanism of EYO is still unknown. Aim of the study The anti-inflammatory activity and mechanism of EYO were investigated in tumor necrosis factor (TNF)-α induced Caco-2 cells. Materials and methods EYO was obtained by direct-heat extraction (HE), ethanol extraction (EE) and petroleum ether extraction (PE), respectively. Fatty acid compositions of three EYO were measured by gas chromatography (GC). Cell viability, enzyme-linked immunosorbent assay (ELISA), transcriptome, RT-PCR and Western blotting were also performed. Results Fatty acid compositions of three EYO were different with varied extraction methods. EYO significantly reduced interleukin (IL)-8 secretion. EYO exerted anti-inflammatory effect via coordinating regulation of Nrf2/NF-κB pathways based on the results of transcriptome, Q-PCR and Western blotting. In detail, PE and HE inhibited the NF-κB pathway, whereas EE exerted anti-inflammatory activity via the Nrf2/NF-κB pathways. Conclusions The aforementioned results showed the anti-inflammatory mechanism of EYO. These findings might be beneficial to clinical applications of EYO.

Maillard reaction was progressed by incubating the mixture of egg white (EW) and alkali at different temperatures (4 °C, 25 °C and 37 °C) for different days (0, 1, 3, 5 and 7 days), to explore the effects of temperatures and incubating days on physicochemical and antioxidant properties of EW during the treatment of alkali. The results revealed that the color, browning intensity and fluorescence intensity increased with the extended incubating days (P

Nitric oxide (NO) is a signal molecule that can regulate fruit physiology. Several studies have indicated that NO can inhibit the ripening of kiwifruit, but the mechanism underlying this process is unresolved. This study used transcriptome analysis to identify the essential genes related to NO regulation during kiwifruit softening. NO gas fumigation (15 μl L-1) significantly delayed kiwifruit softening. There were 736 differentially expressed genes (DEGs) between the NO treatment and the control. The expression levels of polygalacturonase (PG), pectate lyase (PL), β-galactosidase (β-GAL), pectinesterase (PE), and the beta-amylases-related genes decreased in response to the NO treatment, while those of four genes encoding cellulose synthase increased. The expression of genes related to ethylene biosynthesis and signal transduction also differed; the expression levels of 1-aminocyclopropane carboxylic acid oxidase (ACO), the ethylene receptors (ERS1, ETR2), and the ethylene-responsive transcription factors (ERF016, ERF7, ERF010, ERF062, ERF110, ERF037, ERF008, ERF113, ERF12, ERF095) were lower in the NO-treated kiwifruit. Expression of the calcium ion (Ca2+) signal-related genes (CNGC1, CPK1, CIPK2, CML31, CML48, ZIFL1) significantly differed and may be involved in the regulation of the NO softening response. These findings add to our understanding of the molecular mechanisms of the NO-delayed softening response in kiwifruit.

Current study aimed to evaluate the effects of fumigation with 15 μl L−1 nitric oxide (NO) on the quality of ‘Newhall’ navel orange fruit during storage at 5 °C. Fruits quality parameters, decay rate, antioxidant capacity, antioxidant enzymes activities and disease resistance related enzymes activities were evaluated. NO treatment significantly inhibited the increasing weight loss, maintained soluble solid content (SSC), titratable acid (TA) and vitamin C (VC) contents (P

In this study we investigated the changes in the physicochemical properties, microstructure, protein structure, and intermolecular forces in egg yolk, plasma, and granule gels induced with a strong alkali. The results showed that egg yolks formed a three-dimensional gel, maintained by ionic and disulfide bonds from plasma and granules, respectively. According to spin–spin relaxation time, these gel systems fixed numerous water and lipid protons. Microstructure showed that egg yolks, plasma, and granules liberated their constituents on disruption, which randomly aggregated or bonded. Under a continuous strong alkali treatment, the second-derivative spectra of egg yolks and plasma appeared as an “aggregation band”, while the ordered structure of granules decreased. The results suggested that the aggregation of alkali-induced egg yolks formed mainly due to structural changes in plasma proteins. Granules contributed to the increased hardness and the bonding of egg yolk gels via disulfide bonds induced by alkali treatment.

The effects of fumigation with NO, H2S and combination of both on the quality, ethylene biosynthesis and softening of postharvest ‘Dahong’ peach fruit were investigated in current study. Results showed that NO or H2S significantly inhibited the increase of rot index, soluble solid contents, decrease of firmness along with titratable acid contents (P

In this paper, the physicochemical and nutritional characteristics of preserved duck egg white were analyzed and compared with fresh egg and hard-cooked egg white (n = 3). The data obtained showed that the preserved egg white was rich in essential amino acids and minerals, such as Ca, Mg, Fe, Zn, Cu, K, and Na. After fresh duck eggs were processed into preserved eggs, contents of moisture, CP, amino acid, and water-soluble vitamin of egg white significantly decreased (P < 0.05); however, pH, free amino acid content, and most inorganic elemental contents of egg white significantly increased (P < 0.05). The preserved egg white had higher a* (redness/greenness) and b* values (yellowness/blueness; P < 0.05) and lower L* value (lightness; P < 0.05) than hard-cooked egg white. The gel hardness of preserved egg white was approximately 50% of hard-cooked egg white; however, its springiness and cohesiveness were approximately 1.5 times of hard-cooked egg white. The results indicated that pickling with alkaline and other additives can significantly change physical properties and chemical composition of duck egg white, which make preserved egg white with characteristics of rich elements, brown color, and high springiness, but low vitamin.