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Brassinosteroids (BRs) play essential roles in regulating plant growth and development, however, gaps still remain in our understanding of the BR signaling network. We previously cloned a grain length quantitative trait locus qGL3, encoding a rice (Oryza sativa L.) protein phosphatase with Kelch-like repeat domain (OsPPKL1), that negatively regulates grain length and BR signaling. To further explore the BR signaling network, we performed phosphoproteomic analysis to screen qGL3-regulated downstream components. We selected a 14-3-3 protein OsGF14b from the phosphoproteomic data for further analysis. qGL3 promoted the phosphorylation of OsGF14b and induced the interaction intensity between OsGF14b and OsBZR1. In addition, phosphorylation of OsGF14b played an important role in regulating nucleocytoplasmic shuttling of OsBZR1. The serine acids (Ser258Ser259) residues of OsGF14b play an essential role in BR-mediated responses and plant development. Genetic and molecular analyses indicated that OsGF14b functions as a negative regulator in BR signaling and represses the transcriptional activation activity of OsBZR1. Collectively, these results demonstrate that qGL3 induces the phosphorylation of OsGF14b, which modulates nucleocytoplasmic shuttling and transcriptional activation activity of OsBZR1, to eventually negatively regulate BR signaling and grain length in rice.

The immune regulation function of ovotransferrin (OVT) explored using the RAW264.7 was induced by lipopolysaccharide (LPS) as vitro model in this study. The results showed that RAW264.7 cultured with OVT (200 μg/ml) alone not only enhanced the phagocytic activity and the production and expression of inflammatory factors, but also expression of toll‐like receptor 4 (TLR4) gene was significantly promoted by OVT. OVT (50 μg/ml) significantly inhibited the secretion and expression of inflammatory factors in LPS‐stimulated RAW264.7, but CD14 and TLR4 genes expressions were no obvious effects. Inflammatory cytokines and NO secreted by OVT‐induced macrophages pretreated with inhibitors of TLR4 were down‐regulated. We further verified the effects of OVT on inflammatory signaling pathway‐related proteins through immunofluorescence and western blotting, MyD88, TLR4 and the phosphorylation of IκBα and p65 were significantly promoted by OVT, but there was no significant effects on the phosphorylation of IRF3. OVT promoted the phosphorylation of ERK and p38 in RAW264.7 and inhibited the phosphorylated expression of MAPK in LPS‐mediated inflammation. These results indicated that OVT had the bidirectional immunoregulatory function through TLR4‐mediated NF‐κB/MAPK signaling pathway, that is, anti‐inflammatory effect of low concentration and immune‐enhancing activity of high concentration were showed. That provides a theoretical utilization for the development and utilization of OVT., Ovotransferrin had the bidirectional immunoregulatory function through TLR4‐mediated NF‐κB/MAPK signaling pathway, that is, anti‐inflammatory effect of low concentration and immune‐enhancing activity of high concentration were showed.

Egg white protein (EWP) was one of the high-quality protein sources and widely used in the food industries because of excellent emulsifying, gelling, and foaming properties. Polysaccharides as a natural biological macromolecule have been used to improve the functional properties of EWP. The electrostatic interaction was the main driving force between EWP and polysaccharides. However, protein-polysaccharides complexes were susceptible to environmental factors including pH, ionic strength, polymer ratio, and temperature. In this paper, the functional properties of EWP were summarized. More importantly, the effects of polysaccharides on the functional properties of EWP were highlighted and reviewed referring to emulsifying, foaming, and gelling properties. The impact of environmental factors on the protein-polysaccharides interaction were also discussed. This paper leaded to enrich research systems of protein-polysaccharides interaction and provided information for the development of new egg white-derived foods.

To determine furaltadone metabolites 5-methylmorpholino-3-amino-2-oxazolidinone (AMOZ) residual levels in ctenopharyngodon idellus, direct competitive enzyme-linked immunosorbent assay (dcELISA) was developed based on a single-chain variable fragment (scFv)-alkaline phosphatase (AP) fusion protein. Firstly, VH and VL gene sequences were cloned from hybridoma cell lines secreting monoclonal antibody against AMOZ derivative, and then the productive VH and VL genes were assembled to a scFv gene and engineered to produce scFv-AP fusion protein. The fusion protein was further identified as a bifunctional reagent for immunoassay, then a sensitive one-step dcELISA against AMOZ derivative was developed with a half-maximal inhibitory concentration (IC50) and limit of detection (LOD) of 10.62 and 4.83 ng/mL, respectively. The recovery values of AMOZ from spiked fish samples determined by dcELISA were in 71.31%∼82.88%. The results suggested that the prepared scFv-AP fusion protein in this work can be used for rapid and convenient immunoassays to detect AMOZ residues in fish samples.

BACKGROUND Hydrogen sulfide (H2 S) is a known signaling molecule in plants, which has the ability to delay fruit ripening. Our previous studies have shown that H2 S treatment could delay the maturation of kiwifruits by inhibiting ethylene production, improving protective enzyme activities, and decreasing the accumulation of reactive oxygen species to protect the cell membrane during storage. The mechanism related to the way in which H2 S affected kiwifruit maturation was still unclear. We performed transcriptome sequencing to explore the influences of H2 S on the softening of kiwifruit. RESULTS The firmness and the soluble solids content (SSC) of the kiwifruit were significantly better maintained with H2 S treatment compared to the control during the storage period (P

Rice (Oryza sativa L.) is one of the most important crops in the world, and grain size is a major component determining rice yield. Recent studies identified a number of grain size regulators, which are involved in the phytohormone signaling, G protein signaling, mitogen-activated protein kinase signaling pathway, ubiquitin-proteasome pathway, or transcriptional regulation. In previous study, we cloned qGL3/OsPPKL1 encoding a rice protein phosphatase that negatively modulates brassinosteroid (BR) signaling and grain length. Here, to further explore qGL3-mediated BR signaling network, we performed phosphoproteomic screenings using two pairs of rice materials: the indica rice cultivar 9311 and its near-isogenic line NILqgl3 and the japonica rice cultivar Dongjin and its qGL3 knockout mutant m-qgl3. Together with qGL3-interacting proteins, we constructed the qGL3-mediated network, which reveals the relationships between BR signaling and other critical signaling pathways. Transgenic plants of these network components showed BR-related alterations in plant architecture. From this network, we validated a qGL3-interacting protein, O. sativa VERNALIZATION INSENSITIVE3-LIKE1 (OsVIL1), and demonstrated that qGL3 dephosphorylates OsVIL1 to modulate BR signaling. The qGL3-dependent network uncovered in this study increases our understanding of BR signaling and provides a profound foundation for addressing how BR modulates plant architecture in rice.

This work investigates the role of hydrogen sulfide (H2S) in the browning and regulating the antioxidant defensive system in fresh-cut Chinese water chestnuts. The samples were fumigated with 0, 10, and 15 μl L−1 of H2S and stored at 10°C for 8 days. The results indicated that the H2S treatment significantly inhibited the browning of fresh-cut Chinese water chestnuts, reduced superoxide anion (O2·-) production rate and H2O2 content accumulation, promoted the increase of total phenol content, and enhanced activities of catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR) (P < 0.05). On the other hand, phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) activities remained at a low level in the H2S treatment (P < 0.05). This result suggested that H2S treatment might be a promising approach to inhibit browning and prolong the shelf life by enhancing oxidation resistance and inhibiting browning enzyme activity of fresh-cut Chinese water chestnuts during storage. Among them, the 15 μl L−1 H2S treatment had the best effect on fresh-cut Chinese water chestnuts.

BACKGROUND The texture and structure of the duck egg white (DEW) gel under salt and heat treatment are crucial to its digestibility. Specifically, the structural changes of food protein gels have been recognized for their potential to regulate in vitro digestion. In this study, the effects of gel characteristics and simulated in vitro gastrointestinal digestion of DEW under combined salt and heat treatment were investigated. RESULTS With the increase in salting time and temperature, a porous opaque gel with large particles was formed, the moisture content of DEW showed a downward trend, and the same was true for hardness changes. The microstructure suggested that, with the penetration of NaCl, DEW proteins were denatured, and the protein molecules gradually unfolded and then aggregated after 7 days. The secondary structure revealed that, as the salting time and temperature increased, the proportion of intermolecular β-sheets and α-helices decreased. In terms of in vitro digestion, the highest digestibility was obtained at 14 days of salting combined with 100 °C heat treatment, and the digestibility was the lowest when marinated for 7 days at 121 °C. Liquid chromatography and tandem mass spectrometry (LC-MS/MS) indicated that the number of different types of peptides and specific peptides was positively correlated with the salting time and temperature of the DEW at the end of gastric digestion. CONCLUSIONS Heat treatment at 100 °C has a higher in vitro digestibility than at 121 °C. Gels with low hardness, large pores, and rough textures are easier to digest by pepsin and release more peptides. © 2021 Society of Chemical Industry.

Current research aimed at studying the effect of benzothiazole (BTH) on the fruit quality and resistance against Penicillium italicum (P. italicum). Recently, a synthetically prepared novel BTH was introduced that elicits the induction of resistance against various diseases of fruits. However, little was reported on the effect of BTH on the disease resistance and fruit quality of postharvest navel orange fruit. In this study, 50 mg·L−1 BTH significantly reduced the decay rate of fruits during 36 days of storage at 20 ± 0.5°C ( P < 0.05 ). BTH markedly inhibited the weight loss rate in fruits ( P < 0.05 ) and effectively maintained higher soluble solid content (SSC), titratable acid (TA), and vitamin C (VC) content compared with control navel orange fruits. Further, BTH significantly suppressed the increase of disease incidence and lesion area of orange fruits challenged with P. italicum ( P < 0.05 ). BTH treatment significantly enhanced antioxidant capacity (DPPH, ABTS radical scavenging activity, and reducing power), and superoxide dismutase (SOD) and peroxidase (POD) activities were significantly increased, while the activity of catalase (CAT) was opposite to the former ( P < 0.05 ). The activities of β-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), and chalcone isomerase (CHT) were significantly higher in BTH-treated navel orange fruits ( P < 0.05 ). Our results suggested that BTH treatment may be a promising treatment for maintaining the quality and inhibiting blue mold of postharvest navel orange in the future.

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.

Ovotransferrin (OVT) is one of the major proteins in avian albumen that exerts diverse biological activities. This study is aimed to investigate the antiviral effect and mechanism of OVT from the avian egg. Effects of OVT on vesicular stomatitis virus (VSV)-infected mouse peritoneal macrophage were detected by real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and western blot. In OVT-pretreated mouse peritoneal macrophages, results showed that replication of VSV was significantly suppressed and production of type I interferon (IFN) was increased. OVT down-regulated ring finger protein 125 (RNF125) production and up-regulated retinoic-acid-inducible gene I (RIG-I) expression by the nuclear factor-κB signalling pathway, resulting in the enhancement of the production of type I IFN. It demonstrated that the antiviral effect of OVT on innate immunity is enhanced by promoting type I IFN expression, indicating its potential as a functional food ingredient.

Scope Inflammation is the pathological basis of many chronic diseases, and persistent intestinal inflammation is a key factor in the further development of colon cancer. Egg-derived peptides have been proven to have anti-intestinal inflammation activity. Egg white treated with salt contains a lot of rich protein, whether its peptides have anti-inflammatory activity and how their mechanism of action is still unclear. Methods and results In this study, ELISA was used to determine the anti-inflammatory activity of the peptides (VF-4 and DR-8 from salted egg white), and then RNA-seq was used to explore the mechanism of their anti-inflammatory activity, and then verified by western blotting and inhibitors. The results showed that VF-4 and DR-8 significantly inhibited TNF-α-induced IL-8 secretion in HT-29 cells in a concentration-dependent manner, and VF-4 showed a more significant anti-inflammatory effect than DR-8. The anti-inflammatory mechanism of VF-4 and DR-8 was through inhibiting the activation of NF-κB, MAPK, and PI3K-Akt pathways, reducing the production of inflammatory mediators. Conclusion VF-4 and DR-8 have obvious anti-inflammatory activity, which can reduce intestinal inflammation and inhibit its further development into colon cancer. This article is protected by copyright. All rights reserved.

Proteins and bioactive peptides in avian egg whites exert anti-inflammatory activity. Here, we aimed to evaluate the anti-inflammatory effect of ovotransferrin (OVT) and its di-peptides by simulated peptide-cut using an in vitro model of TNF-α-induced inflammation in Caco-2 cells. Results showed that co-treatment with OVT can’t inhibit the IL-8 secretion in TNF-α-induced Caco-2 cells. Among 18 di-peptides derived from OVT based on simulated peptide-cut, CR, FL, HC, LL and MK markedly decreased IL-8 secretion. Furthermore, these five di-peptides were able to significantly inhibited gene expression of pro-inflammatory cytokines, including TNF-α, IL-8, IL-6, IL-1β, and IL-12, and promoted gene expression of anti-inflammatory cytokines, such as IL-10, in Caco-2 cells. CR, FL, HC, LL and MK inhibited the phosphorylation of inhibitor of κB (IκB). Meanwhile, CR and HC decreased the phosphorylation of p-JNK and p-p-38. These results indicated that CR and HC inhibited the NF-κB and MAPK signaling pathway in TNF-α-induced Caco-2 cells. Nevertheless, LL, FL and MK exerted their anti-inflammatory activity via MAPK signaling pathway. The study suggested that CR, FL, HC, LL and MK have the potential to attenuate intestinal inflammation.

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

Changes in the gelation behavior and mechanism were investigated in low-density lipoprotein (LDL) and high-density lipoprotein (HDL) under the treatment of alkali. Three textural parameters of two kinds of alkali-induced lipoprotein increased, especially the springiness of LDL and the hardness of HDL. Alkaline treatment contributes to the sulfhydryl (SH) oxidation and SH-disulfide bonds (SS) exchange reactions to produce SS, promoting the aggregation of proteins and the formation of lipoprotein gels. For LDL gels, the increased hydrophobic interaction improves its thermal stability. HDL underwent deep unfolding and reassemble to form a network structure with high thermal stability and uniform density. Continuously alkaline treatment destroyed less SS and exposed more buried SH. The decrease of β-structures in both lipoproteins was observed by Fourier Transform Infrared (FTIR). These results suggested that alkali-induced LDL and HDL gelation behavior highly related to the protein structure, SS and hydrophobic interactions.

In this paper, the relationship between protein structure changes and in vitro digestion of preserved egg white (PEW) during pickling was studied. Results showed that as the pickling time increased, moisture content of PEW exhibited a decreasing trend, pH value and hardness of PEW exhibited an increasing trend. Environmental Scanning Electron Microscopy (ESEM) revealed that alkali-treated duck egg white could form a more compact gel network structure during pickling. Transmission Electron Microscopy (TEM) showed that PEW consisted of two sorts of structures, namely fibrillar (from 7th to 21st day) and particulate (from 28th to 42nd day). Fourier Transform Infrared (FTIR) spectroscopy showed that there was an increase in the content of β-sheets and a decrease in the content of α-helices during pickling. Protein digestibility of PEW was highest at day 14 and the lowest at day 42. Moreover, the content of β-sheets was negatively correlated with protein digestibility. Peptides identification using LC-MS/MS highlighted that the number of different peptides were positively correlated with the pickling. The number of unique peptides was negatively correlated with protein digestibility at the end of gastric and intestinal digestion. This study would provide guidance for studying nutritional value and controlling quality of preserved eggs.

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

Simulated gastrointestinal digestion of preserved egg white (SGD-PEW) exerts anti-inflammatory effects on Caco-2 cells and a mouse model of DSS-induced colitis. Here, we aimed to separate peptides derived from SGD-PEW and evaluate their anti-inflammatory effects using an in vitro inflammatory model. Six peptides were isolated and identified. DEDTQAMPFR (DR-10), DEDTQAMPF (DF-9), MLGATSL (ML-7) and MSYSAGF (MF-7) significantly inhibited IL-8 secretion and markedly decreased gene expression, including TNF-α, IL-8, IL-6, IL-1β and IL-12 and promoted IL-10 gene expression in Caco-2 cells. DR-10, DF-9, ML-7 and MF-7 significantly inhibited the phosphorylation of JNK. In the meantime, DR-10 and DF-9 significantly reduced the phosphorylation of IκB and p38. These results indicated that ML-7 and MF-7 exerted their anti-inflammatory activity through the MAPK signaling pathway in TNF-α-induced Caco-2 cells. Whereas, DR-10 and DF-9 inhibited the NF-κB and MAPK signaling pathways. The results suggested that DR-10, DF-9, ML-7 and MF-7 derived from SGD-PEW may be a new type of prophylactic food for the treatment of inflammation.

Changes in physico-chemical properties, microstructure, protein structures and intermolecular force of egg yolk, plasma and granule gels during salting were investigated, using low-field nuclear magnetic resonance (LF-NMR), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and chemical analysis. The results showed that the contents of soluble protein and free sulfhydryl increased and, with D2O treatment, T21 and T22 decreased in egg yolks and plasma salted for 2 d. The particles of egg yolks, plasma and granules in the later stage of salting were disrupted and they liberated their constituents (phospholipids, neutral lipids and proteins), which randomly aggregated. The treatment with NaCl changed the spatial structure of egg yolk proteins. The results suggested that the oil exudation of salted egg yolks was mainly due to structural changes in the low-density lipoproteins. Granules were shown to contribute to the higher hardness and gelation of salted egg yolks.

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.

In order to illuminate the forming process of salted egg, the effects of the brine solution with different salt concentrations on the physicochemical properties, textural properties, and microstructures of duck eggs were evaluated using conventional physicochemical property determination methods. The results showed that the moisture contents of both the raw and cooked egg whites and egg yolks, the springiness of the raw egg yolks and cooked egg whites exhibited a decreasing trend with the increase in the salting time and salt concentration. The salt content, oil exudation and the hardness of the raw egg yolks showed a constantly increasing trend. Viscosity of the raw egg whites showed an overall trend in which it first deceased and then increased and decreased again, which was similar to the trend of the hardness of the cooked egg whites and egg yolks. As the salting proceeded, the pH value of the raw and cooked egg whites declined remarkably and then declined slowly, whereas the pH of the raw and cooked egg yolks did not show any noticeable changes. The effect of salting on the pH value varied significantly with the salt concentration in the brine solution. Scanning electron microscopy (SEM) revealed that salted yolks consist of spherical granules and embedded flattened porosities. It was concluded that the treatment of salt induces solidification of yolk, accompanied with higher oil exudation and the development of a gritty texture. Different salt concentrations show certain differences.

BACKGROUND Exogenous hydrogen sulfide (H2S) treatment can prolong the postharvest life of cut flowers and strawberries. Little work has been done to explore the effects of H2S on respiratory climacteric fruits such as kiwifruits during storage. Therefore the aim of the present study was to evaluate the effects of H2S treatment at concentrations of 15–1000 µmol L−1 on the postharvest life of kiwifruit during 25 °C storage and the role of H2S in regulating the antioxidant defensive system of kiwifruit. RESULTS Treatments with 45 and 90 µmol L−1 H2S significantly inhibited the increase in soluble sugar content and the decrease in vitamin C (Vit C), chlorophyll content and firmness, inhibited ethylene production and both superoxide production rate (O.2−) and hydrogen peroxide content. Kiwifruits with 45 and 90 µmol L−1 H2S exhibited significantly higher activities of superoxide dismutase, catalase and peroxidase. Treatment with 180 µmol L−1 H2S promoted the ripening of kiwifruits. CONCLUSION Treatments with 45 and 90 µmol L−1 H2S could delay the maturation and senescence of kiwifruits and maintain higher titratable acid (TA) and Vit C during eating-ripe storage by inhibiting ethylene production, improving protective enzyme activities and decreasing the accumulation of reactive oxygen species to protect the cell membrane during storage. © 2014 Society of Chemical Industry

In the present study, 20 inorganic elements in three parts of preserved eggs prepared with different metal ions, including Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Li, K, Mg, Mn, Mo, Na, P, Pb, Zn, Se, and Sr, were determined simultaneously by using inductively coupled plasma–atomic emission spectrometry (ICP-AES). The recoveries obtained by the standard addition method ranged between 84.4 and 112.2 %, and RSDs were lower than 8.76 %, The detection limits of the method for the 20 elements were in the range of 0.4–10 μg L−1. The determination results showed that three parts of preserved eggs prepared with different metal ions are all rich in essential inorganic elements, such as Na, K, P, Ca, Mg, Fe, Cu, and Zn, and the contents of most of the inorganic elements in egg yolk are higher than in egg white. In comparison with fresh duck eggs, the contents of Na, Cu, Fe, Al, and Mn are significantly increased in three parts of preserved eggs prepared with different metal ions. Metal ions added in pickling solution would significantly affect the content of element added in preserved eggs. High contents of Pb (20.15 μg/g in egg shell, 18.99 μg/g in egg white, and 0.96 μg/g in egg yolk) were found in preserved eggs with PbO. Meanwhile, the experimental results indicated that the ICP-AES technique is easy to operate, rapid, accurate, and highly sensitive to determine many inorganic elements simultaneously in preserved egg.