Search

As a natural emulsifier, egg white protein (EWP) has great interfacial characteristics and high security, and has broad development prospects. This study explored the impact of ultrasound synergized citral (CI) treatment on the microstructure, molecular flexibility and emulsifying property of EWP, and predicted the interaction between CI and ovalbumin (the main protein in EWP) through molecular docking. The decrease in free amino content and the growth in molecular weight of EWP suggested that CI and proteins were successfully grafted. The results of physicochemical properties revealed that UCEWP (ultrasound synergized citral-treated EWP) had smaller particle size and larger ζ-potential absolute value, which meant that the stability of UCEWP system was enhanced. From the perspective of interfacial characteristics, UCEWP had lower interfacial tension, which remarkably improved its emulsifying property. The emulsifying activity index (EAI) and emulsifying stability index (ESI) of UCEWP were 1.99 times and 3.19 times higher than that of natural EWP (NEWP). Analysis of Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectroscopy illustrated that the secondary and tertiary structures of UCEWP were more disordered and stretched than those of EWPs. Protein microstructure demonstrated that UCEWP presented loose small particle distribution, and correlation analysis reflected that the improvement of molecular flexibility was positively correlated with the enhancement of emulsifying property. These results elucidated that ultrasound synergized CI treatment is an effective mean to improve the molecular flexibility and emulsifying property of EWP, which provides a valuable reference for further application of EWP.

ABSTRACT: Chicken egg yolk plasma (EYP), the supernatant fraction of egg yolk obtained by water dilution and centrifugation, is a rich source of various bioactive substances and a significant bearer of yolk-emulsifying properties. This study utilized proteomics to conduct a comprehensive and in-depth analysis of both common and modified EYP proteins (phosphorylated proteins and N-glycosylated proteins). Total of 208 proteins were identified in EYP, including 42 phosphorylated proteins with 137 phosphorylation sites and 150 N-glycoproteins with 332 N-glycosylation sites. Among the phosphorylation sites, tyrosine accounted for 80.6%, while the N-glycosylation sites predominantly featured “N-X-T” motifs, accounting for 58.7%. Functional enrichment analysis revealed that most proteins were involved in regulating enzyme activity and inhibition with a particular focus on modulating peptidase activity. Notably, vitellogenins-2 (30 phosphorylation sites, 9 N-glycosylation sites) and apolipoprotein B (10 phosphorylation sites, 56 N-glycosylation sites) were the 2 proteins with the most modification sites. Additionally, EYP was found to contain the highly N-glycosylated complement proteins C3 and C4. These findings provide new insights into the protein composition of EYP and its roles in chicken embryo development and immune defense, offering a theoretical foundation for the application of EYP in various fields.

Low-temperature cooking causes flavor weakness while improving the texture and digestive properties of meat. To enhance the flavor of low-temperature cooked Tibetan pork, samples were cooked at low-temperature with or without ultrasound-assisted (UBTP, BTP) for different times (30 min, 90 min) and then analyzed using GC–MS and LC-MS. The results showed that ultrasound-assisted cooking caused a significant increase in lipid oxidation by 9.10% in the early stage of the treatment. Additionally, at the later stage of ultrasound-assisted processing, proteins were oxidized and degraded, which resulted in a remarkable rise in the protein carbonyl content by 6.84%. With prolonged effects of ultrasound and low-temperature cooking, the formation of phenylacetaldehyde in UBTP-90 sample originated from the degradation of phenylalanine through multivariate statistics and correlation analysis. Meanwhile, trans, cis-2,6-nonadienal and 1-octen-3-one originated from the degradation of linolenic acid and arachidonic acid. This study clarified the mechanism of ultrasound-assisted treatment improving the flavor of low-temperature-cooked Tibetan pork based on the perspective of lipids and proteins oxidation, providing theoretical supports for flavor enhancement in Tibetan pork-related products.

The challenge of meat quality degradation due to transportation difficulties in high-altitude plateaus underscores the importance of an efficient thawing process for Tibetan pork to ensure its quality. This study compared four thawing methods ultrasound thawing (UT), refrigerator thawing (RT), hydrostatic thawing (HT), and microwave thawing (MT) to assess their impact on the quality of Tibetan pork, focusing on thawing loss, tenderness, color variation, and alterations in protein secondary structure and moisture content. Additionally, the study examined the impact of thawing on the metabolites of Tibetan pork using metabolomics techniques. The results indicated that UT yielded the highest quality samples. UT significantly accelerated the thawing rate and had minimal impact on tenderness compared to traditional thawing methods. Moreover, protein and lipid oxidation levels were reduced by UT treatment. Furthermore, it enhanced the binding capacity of protein and water molecules, reduced drip loss, and maintained meat color stability. What’s more, amino acid metabolites such as l-glutamic acid, l-proline, oxidized glutathione, and 1-methylhistidine played a significant role in thawing oxidation in Tibetan pork, exhibiting a positive correlation with protein oxidation. UT resulted in a notable decrease in the levels of hypoxanthine and 2-aminomethylpyrimidine, contributing to the reduction of bitterness in the thawed meat and consequently enhancing the freshness of Tibetan pork. This study offers novel insights into understanding the biological changes occurring during the thawing process, while also furnishing a theoretical framework and technical assistance to improve the quality of Tibetan pork and propel advancements in food processing technology.

Gelatin is a protein molecule that can be hydrolyzed from collagen, animal bones, skin and it easily soluble in water. Source animals for gelatin ingredients must be evaluated, as well as their halal status. The omics method towards gelatin authentication in food and pharmaceutical products has several advantages, including high sensitivity and reliable data. Omics investigation employs the process of breaking down substances into small particles, hence enhancing the ability to detect a greater number of compounds. Omics study has the capability to identify substances at the subclass level, which makes it highly suitable for gelatin authentication. Gelatin lipids, metabolites, proteins, and volatile chemicals can be utilized as references to authenticate gelatin. In adopting gelatin authentication, lipidomics, metabolomics, proteomics, and volatilomics must be combined with chemometrics for data interpretation. Chemometrics can convert omics analysis data into easily viewable data. Chemometric approaches capable of presenting omics analysis data for gelatin authentication include PCA, HCA, PLS-DA, PLSR, SIMCA, and FACS. Visually chemometrically explain the differences in gelatin from different animal sources. The combination of omics analysis and chemometrics is a very promising technology for gelatin authentication in food and pharmaceutical products.

SUMMARY: The primary proteins in egg whites are glycoproteins, which are hydrolyzed by digestive enzymes to produce substantial egg white glycopeptides (EWGs). However, the potential role of EWG has not been reported. In this study, EWG was obtained through simulated digestion in vitro and affinity chromatography enrichment, and we further examined the effect of EWG on protein expression in mouse macrophages (RAW264.7) through quantitative proteomic analysis. Compared to the control group, 149 differentially expressed proteins (DEPs) were upregulated, and 35 DEPs were downregulated in RAW264.7 cells by treatment with EWG (125 µg/mL). These DEPs were related to 76 KEGG pathways (such as “NF-kappa B signaling pathway,” “TNF signaling pathway,” “C-type lectin receptor signaling pathway”) and 12 protein domains (such as “Lectin C-type domain,” “Immunoglobulin domain,” “Immunoglobulin V-set domain”), which suggested that EWG could exert immunomodulatory effects through immune signaling pathways and protein domains. Our findings provide promising signaling pathways for in-depth exploration of the immunomodulation of EWG and contribute to the development of EWG as a potential immunoactivity ingredient.

ABSTRACT: Ultrasound-induced egg white fluidic gels (UEFG) were prepared through ultrasonic pretreatment followed by subsequent heating. The optimal preparation parameters for UEFG were: ultrasonic power density between 0.2 to 0.8 W/mL, ultrasonic treatment time surpassing 150 s, heating temperature within 70 to 76°C, and heating time under 16 min. The prepared UEFG is a milky white solution with a viscosity lower than that of fresh egg white, and displayed a particle size distribution primarily between 100 and 1,200 nm. Stability assessments conducted over 28 d at 4°C revealed that UEFG remained stable at pH 6-10, with exceptional stability from pH 8 to 10, while it is less stable in highly acidic (pH 2-4) or basic environments (pH 12). The UEFG also showed commendable stability in the presence of salt and sucrose solutions. We report a simple and novel method for preparing UEFG with good flowability after heating treatment. The UEFG has broad applications in the food industry, such as precooked egg white powder, high protein beverages, composite dairy products, etc.

ABSTRACT: To improve the thermal gel properties of egg yolk, the effect of several valence metal ions (K+, Ca2+, Mg2+ and Fe3+) with different concentrations (0–0.72%) on the rheological, gel, and structural properties of egg yolk were investigated. Results showed that monovalent and divalent ions were beneficial to the formation of uniform and dense gel network, especially with the addition of 0.72% magnesium ion, which further improved gel hardness, water holding capacity (WHC) and viscoelastic properties, the properties of egg yolk gel increased with the increase of the concentration of mono-bivalent metal ions. Adding ferric ion remarkably increased the average particle size (d4,3) and apparent viscosity of egg yolk, destroying the disulfide bonds and the hydrophobic interactions in gel. Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectra analysis revealed that metal ions promoted the hydrophobic aggregation among egg yolk proteins and induced the transition of protein secondary structure from ordered to disordered. This work will provide a theoretical reference for the development of low salt and nutrient fortified egg yolk products.

ABSTRACT: Micro-organisms on the eggshell surface of affect the quality of the egg. Sometimes, these microbes even pose a serious threat to the health of the egg's consumer. Bacterial 16S rDNA and fungal internal transcribed spacer region were sequenced to analyze the microbial diversity on the shell surface of the eggs collected from 4 distinct regions of China: Guyuan (GY; 1.5 million hens), Langfang (LF; 0.1 million hens), Beihai (BH; 1.2 million hens), and Dongguan (DG; 0.2 million hens). The results showed a higher bacterial and fungal abundance on the eggs collected from the northern and southern China farms, respectively. The dominant bacterial phylum detected across all egg samples was Firmicutes. In addition, the shell surfaces of the DG and LF samples harbored abundant levels of Proteobacteria. The dominant fungal phyla detected across all egg samples were Ascomycota and Basidiomycota. The bacterial compositions on eggshell surfaces differed significantly across all geographic regions, and the fungal composition differed significantly between samples collected from the southern and northern farms (P < 0.05). The abundance and composition of microbial colonies on the eggshell surface varied based on their geographical location (climate and environment) and farming scale (management). Our findings provide an important reference for optimizing the cleaning and disinfection methods for fresh eggs collected from different sources.

ABSTRACT: Chicken egg chalaza (CLZ) is a natural colloidal structure in eggs that exists as an egg yolk stabilizer and is similar in composition to egg white. In this study, the proteome, phosphoproteome, and N-glycoproteome of CLZ were characterized in depth. We hydrolyzed the CLZ proteins and enriched the phosphopeptides and glycopeptides. We identified 45 phosphoproteins and 80 N-glycoproteins, containing 59 phosphosites and 203 N-glycosylation sites, respectively. Typically, the ovalbumin in CLZ was both phosphorylated and N-glycosylated, with 4 phosphosites and 4 N-glycosylation sites. Moreover, we identified 2 N-glycosylated subunits of ovomucin, mucin-5B and mucin-6, with 32 and nine N- glycosylation sites, respectively. Analysis of the phosphorylation and N-glycosylation status of CLZ proteins could provide novel insights into the structural and functional characteristics of CLZ.

The dry separate curing of duck egg yolks was carried out by ultrasonic synergize NaCl (sodium chloride) and NaCl alone. The mechanism of the amelioration of salted egg yolk quality by ultrasonic synergistic NaCl dry-curing was studied. The quality variations of the salted egg yolks were analyzed for the same curing time and NaCl content achieved by ultrasonic synergistic NaCl curing and NaCl curing alone. The results showed that under the same salting time, the NaCl content, oil exudation and chewiness of U48-SEY (ultrasonic for 48 h-salted egg yolk) were higher than those in SEY (salted egg yolk). At the same NaCl content, the oil exudation and chewiness of U44-SEY (ultrasonic for 44 h-salted egg yolk) were still significantly increased. Compared to SEY, the soluble protein content and H0 of U44-SEY and U48-SEY were augmented. Scanning electron microscopy (SEM) indicated that the polyhedral particles in the salted egg yolks prepared by ultrasonic synergistic NaCl dry-curing were closely aligned and evenly distributed, and the salted egg yolks were sandier. Structural analysis revealed that the secondary and tertiary structures of egg yolk protein were changed although the ultrasonic synergistic NaCl dry-curing did not cause the fragmentation or aggregation of the peptide chain structure. The above results suggested that ultrasonic not only perfected the quality of salted egg yolk by promoting NaCl penetration, but also modified the structures of egg yolk protein by the action of ultrasonic itself, which prominently improved the quality of salted egg yolks.

Thyme essential oil (TEO) is a natural food antimicrobial agent derived of spice, but suffers from volatility and poor water solubility, which problem can be effectively solved by the encapsulation of liposomes. On this basis, a safe and common natural antibacterial protein, LYZ was used to modify the TEO liposomes (TEO-lips) for gaining better properties. 2.5 mg/mL TEO and 0.05 % LYZ/S100 mass ratio were the best formula for the preparation of LYZ-TEO-lips. After LYZ modification, the particle size and PDI increased, and the zeta potential decreased slightly. The modification of LYZ not only improves the thermal stability of TEO-Lips, weakens the influence of acid and salt ions on liposomes, but also improves the antibacterial properties of TEO-Lips. In brief, LYZ has the potential to improve the overall properties of liposomes and can provide a reference for the development of antimicrobial liposomes.

ABSTRACT: Egg yolk (EY) can be divided into yolk granules (EYG) and yolk plasma (EYP) after water dilution and centrifugation. EYP had a significantly higher lipid content and is predominantly in the form of low-density lipoprotein (LDL) while EYG has a higher protein content. In order to explore the nutritional differences between EY, EYP and EYG, quantitative metabolomic analysis was carried out by ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS). The results showed that a total of 588 small molecule metabolites were identified, mainly glycerol phospholipids (51.59–66.46%), coenzymes, and vitamins (1.21–1.84%). A quantitative comparison showed that amino acids and their metabolites were the most representative metabolites of differential abundance in the contrast of EY and EYG, EYP and EYG. Carbohydrates and their metabolites were the representative metabolites of differential abundance between EY and EYP. The study provided important information for understanding the metabolic composition of EY, EYG, and EYP, as well as providing a reference for utilizing the whole egg.

ABSTRACT: The process of egg yolk formation involves the transport and uptake of a large number of small molecule metabolites. A qualitative and relative quantitative analysis of metabolites in the 3 formation periods of egg yolk was performed by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical workflow. A total of 398 metabolites were identified, of which “amino acids and their metabolites”, “lipid”, and “organic acids and their derivatives” were the dominant egg yolk metabolite categories with the most metabolite species. The findings suggested that a number of amino acids, organic acids, nucleotides and their metabolites were deposited during follicular development to provide material support for later embryonic development. At the same time, some vitamins and carbohydrates were consumed during follicular development to support the normal development process. In addition, the small hierarchical follicle (SF) period may be a critical period for the regulation of the transport and deposition of some active ingredients. These results contribute to a comprehensive understanding of the nutrient deposition pattern and nutritional properties of egg yolk.

This chapter presents a systematic study of the inhibition effect of chlorine dioxide treatment alone and in combination with ultrasound treatment of Salmonella and the physiological metabolic processes within the treated cells. The low-power ultrasound (0.03 W/mL) significantly enhanced the effectiveness (110.00 %) of low concentrations of chlorine dioxide (0.25 mg/L) in inhibiting Salmonella, which, in turn, would significantly reduce the potential environmental impact. In addition, further studies found that low-power ultrasound may enhance the structural and functional damage of chlorine dioxide on Salmonella cell membranes (significant increase in permeability of the outer and inner cell membranes) and disrupt intracellular substance metabolism (small molecule and nucleotide metabolism) and energy metabolism (significant reduction in ATP content and ATPase activity) balance to improve the bacterial inhibitory effect of chlorine dioxide. The results of the study will provide a theoretical basis and methodological guidance for the implementation of “cleaner production” in the food industry.

Natural fiber is not suitable for modifying yolk gel as a modifier because of its large size and high compactness. In this study, two kinds of modified cellulose were selected to improve the thermal gel properties of yolk. The results showed that the two kinds of cellulose promoted the formation of ordered structure in yolk gel. The ordered gel network not only improved the texture properties and rheological properties, but also improved the water retention of yolk gel significantly. CMC and CNFC at the same concentration, the modification effect of CMC on yolk gel was better than CNFC because of its excellent dispersion. However, high concentration of CNFC (1.20–1.60%) disrupted the cross-linking and ordered structure formation of yolk protein, and the quality of gel was significantly reduced.

In this study, a stable aqueous solution of paprika oleoresin (PO, the natural colorant extracted from the fruit peel of Capsicum annuum L) was constructed. The solubility of PO in an alkline aqueous solution (pH 10.95–11.10) increased rapidly. However, the aqueous solution of PO (pH 12.00) was unstable, obvious stratification was observed, and the color retention rate was only 52.99% after 28 days of storage. Chicken egg yolk low-density lipoprotein (LDL) was added combined with ultrasonic treatment to improve the stability of LDL-PO solution. The method could decrease the turbidity by 17.5 %, reduce the average particle size of the LDL-PO solution (13.9%), and enhance the interaction and combination of LDL and PO. The prepared PO aqueous solution was used in yogurt, egg white gel, fish balls and soymilk, and it could significantly improve the color of products and provided potential health benefits.

ABSTRACT: Chicken egg yolk granules (EYG) were the precipitated component of egg yolk after water dilution and centrifugation. Compared with egg yolk, EYG are rich in proteins, phospholipids, and minerals. In this study, an integrated proteomic analysis was carried out to in-depth mapping of the proteome, phosphoproteome, and N-glycoproteome of EYGs. After hydrolysis of the EYG total protein, the hydrolyzed peptides or the enriched phosphopeptides/glycopeptides were identified by liquid chromatography-tandem mass spectrometry. A total of 125 phosphorylation sites from 36 phosphoproteins and 244 N-glycosylation sites from 100 N-glycoproteins were identified in EYG. All 3 vitellogenins (precursors of egg yolk high-density lipoprotein) were heavily phosphorylated and N-glycosylated, of which 37 phosphorylation sites and 32 N-glycosylation sites were identified on vitellogenins-2. A Total of 30 N-glycosylation sites were identified on apolipoprotein-B (precursor of egg yolk low-density lipoprotein), but no phosphorylation site was identified. These phosphorylation and N-glycosylation of EYG proteins provide new insights for understanding the assembly structure and functional characteristics of EYG, thus contributing to its development and utilization.

ABSTRACT: Chicken egg yolk granule is a natural micro–nano aggregate in egg yolk, and its assembly structure varies under different processing conditions. In this study, the effects of NaCl concentration, pH, temperature, and ultrasonic treatment on the properties and microstructure of yolk granule were determined. The results showed that ionic strength (above 0.15 mol/L), alkaline environment (pH 9.5 and 12.0), and ultrasonic treatment induced the depolymerization of egg yolk granule; while freezing-thawing, heat treatment (65°C, 80°C, and 100°C), and mild acidic pH (pH 4.5) induced the aggregation of yolk granule. Scanning electron microscopy observation showed the assembly structure of yolk granule varied with different treatment conditions and confirmed the aggregation-depolymerization of yolk granule under different conditions. Correlation analysis showed that turbidity and average particle size are the 2 most critical indicators that can reflect the aggregation structure of yolk granule in solution. The results are important for understanding the changing mechanism of yolk granule during processing, and provide important information for the applications of yolk granule.

The survival mechanism of Salmonella treated with high-intensity ultrasound (HIU) should be explored to further enhance the bactericidal efficacy of HIU. In this study, culturable Salmonella was reduced by applying HIU. Electron microscope imaging revealed that HIU caused the disintegration of cell structure and leakage of intracellular substances. For the Salmonella after the HIU treatment, key enzymes of the tricarboxylic acid [TCA] cycle were significantly downregulated, which led to a reduced ATP content (45.25%–75.00%), although ATPase activity was augmented by 33.82%–60.64% in the Salmonella. Accordingly, surviving Salmonella could have tolerated the stress of HIU by upregulating their environmental sensing (two-component system), chemotaxis (bacterial chemotaxis), substance uptake (ABC transporter), and ATP production (oxidative phosphorylation). Therefore, synergistically blocking the ATP production, signal transduction, or substance intake of Salmonella offer promising potential strategies to improve the bactericidal effect of HIU in industrial food processing.

Post-translational modification structure of food's proteins might be changed during processing, thereby affecting the nutritional characteristics of the food product. In this study, differences in protein N-glycosylation patterns between milk and yogurt were quantitatively compared based on glycopeptide enrichment, liquid chromatography separation, and tandem mass spectrometry analysis. A total of 181 N-glycosites were identified, among which 142 were quantified in milk and yogurt. Significant alterations in the abundance of 13 of these N-glycosites were evident after the fermentation of milk into yogurt. Overall, the N-glycosylation status of the majority of milk proteins remained relatively unchanged in yogurt, suggesting that their conformations, activities, and functions were maintained despite the fermentation process. Among the main milk proteins, N241 of cathepsin D and N358 of lactoperoxidase were markedly reduced after undergoing lactic acid fermentation to produce yogurt. Furthermore, a comparative analysis of current and previously reported N-glycoproteomic data revealed heterogeneity in the N-glycosylation of milk proteins. To sum up, a quantitative comparison of the N-glycoproteomes of milk and yogurt was presented here for the first time, providing evidence that the fermentation process of yogurt could cause changes in the N-glycosylation of certain milk proteins.

Egg-yolk low-density lipoprotein (LDL) has a natural liposome structure. Using ultrasound-assisted pH-shifting (pH 12), a naturally safe and stable aqueous solution of vitamin D3 (VD3) was constructed employing LDL as the carrier. Images from electron microscopy showed that pH-shifting remodeled LDL molecules, resulting in a dramatic reduction in particle size (∼50%) and an increase in specific surface area, which reduced the turbidity (27.7%) and provided new interfaces for VD3 loading. Fluorescence analyses showed that the binding of VD3 to LDL under pH-shifting was strong, involved quenching, and the binding constant was 6.19 × 104 M−1. Thermogravimetric analysis and Fourier transform-infrared spectroscopy showed that pH-shifting hydrolyzed the esters in LDL to fatty acid salts, and the maximum weight loss of LDL occurred from 381.9 °C to 457.0 °C. Ultrasonic treatment enhanced the binding of LDL and VD3 (binding constant increased to 2.56 × 107 M−1), reduced the particle size, and increased the ζ-potential of the complex between LDL and VD3, thereby resulting in the improvement of solution stability and storage stability of VD3. Ultrasound-assisted pH-shifting could remodel LDL to construct a stable aqueous solution of VD3, which showed the potential of LDL as a carrier for lipid-soluble components.

Yaks (Bos mutus) live in the Qinghai–Tibet plateau. The quality of yak meat is unique due to its genetic and physiological characteristics. Identification of the proteome of yak muscle could help to reveal its meat-quality properties. The common proteome, phosphoproteome, and N-glycoproteome of yak longissimus thoracis (YLT) were analyzed by liquid chromatography-tandem mass spectrometry-based shotgun analysis. A total of 1812 common proteins, 1303 phosphoproteins (3918 phosphorylation sites), and 204 N-glycoproteins (285 N-glycosylation sites) were identified in YLT. The common proteins in YLT were involved mainly in myofibril structure and energy metabolism; phosphoproteins were associated primarily with myofibril organization, regulation of energy metabolism, and signaling; N-glycoproteins were engaged mainly in extracellular-matrix organization, cellular immunity, and organismal homeostasis. We reported, for the first time, the “panorama” of the YLT proteome, specifically the N-glycoproteome of YLT. Our results provide essential information for understanding post mortem physiology (rigor mortis and aging) and the quality of yak meat.

Egg yolks are rich in lipids that are easily altered during processing and storage. In this study, a liquid chromatography-tandem mass spectrometry strategy was used for quantitative lipidomics analysis of egg yolk after spray-drying processing and accelerated storage. Spray-drying treatment caused lipid oxidation (especially the oxidation of free fatty acids), potential hydrolysis of phospholipids, and alteration of the form of certain polyunsaturated fatty acids (docosahexaenoic acid, eicosapentaenoic acid, linolenic acid, and eicosatetraenoic acid) in egg yolk. These lipid alterations caused by the spray-drying process were further aggravated by the accelerated storage process. In detail, following storage, the abundance of free fatty acids, phosphatidic acid and phosphatidylethanolamine decreased further; and the abundance of polyunsaturated fatty acids in the form of triglycerides increased significantly. These results provide new insight into the mechanism underlying egg yolk property changes during spray-drying and storage, and offer valuable reference data for egg yolk powder promotion and application in food processing.

Boiling has important effects on the texture of chicken eggs, but its effects on egg nutrients have not been systematically investigated. In this study, changes in the metabolites of egg yolks boiled under different heating intensities were quantified and compared by metabolomic analysis. A total of 797 metabolites were identified, and the abundance of 162 metabolites changed significantly after boiling. The significant reduction of L-lysine and D-fructose suggested that Maillard reactions occurred in over-boiled egg yolks. Egg yolk endogenous enzymes might induce a partial hydrolysis of proteins and phospholipids during the warm-up period of boiling, as the abundance of dipeptides, lysophospholipids, and free fatty acids was significantly increased in boiled egg yolks. Boiling increased the detectable abundance of fat-soluble vitamins, riboflavin, and biotin, possibly by altering the complex structure of protein-lipid-lipophilic compounds or denaturing vitamin-binding proteins. The results of metabolomic analyses provide important information for understanding the nutritional changes of egg yolk boiled under different heating intensities.

In order to expand the applications of plant protein in food formulations, enhancement of its functionalities is meaningful. Herein, the effects of ultrasonic (20 KHz, 400 W, 20 min)-assisted pH shift (pH 10 and 12) treatment on the structure, interfacial behaviors, as well as the emulsifying and foaming properties of perilla protein isolate (PPI) were investigated. Results showed that the solubility of PPI treated by ultrasonic-assisted pH shift (named UPPI-10/12) exceeded 90 %, which was at least 2 and 1.4 times that of untreated PPI and ultrasound-based PPI. Meanwhile, UPPI-10/12 possessed higher foamability (increasing by at least 1.2 times) and good emulsifying stability. Ultrasonic-assisted pH shift treatment decomposed large PPI aggregates into tiny particles, evident from the dynamic light scattering (DLS) and atomic force microscopy results. Besides, this approach induced a decrease in α-helix of PPI and an increase in β-sheet, which might result in the exposure of the hydrophobic group on the structural surface of PPI, thus leading to the increase of surface hydrophobicity. The smaller size and higher hydrophobicity endowed UPPI-10/12 faster adsorption rate, tighter interfacial structure, and higher elastic modulus at the air- and oil–water interfaces, evident from the cryo-SEM and interfacial dilatational rheological results. Thus, the emulsifying and foaming properties could evidently enhance. This study demonstrated that ultrasonic-assisted pH shift technique was a simple approach to effectively improve the functional performance of PPI.

Summary: Mutations in ERCC2/XPD helicase, an important component of the TFIIH complex, cause distinct human genetic disorders which exhibit various pathological features. However, the molecular mechanisms underlying many symptoms remain elusive. Here, we have shown that Ercc2/Xpd deficiency in zebrafish resulted in hypoplastic digestive organs with normal bud initiation but later failed to grow. The proliferation of intestinal endothelial cells was impaired in ercc2/xpd mutants, and mitochondrial abnormalities, autophagy, and inflammation were highly induced. Further studies revealed that these abnormalities were associated with the perturbation of rRNA synthesis and nucleolar stress in a p53-independent manner. As TFIIH has only been implicated in RNA polymerase I-dependent transcription in vitro, our results provide the first evidence for the connection between Ercc2/Xpd and rRNA synthesis in an animal model that recapitulates certain key characteristics of ERCC2/XPD-related human genetic disorders, and will greatly advance our understanding of the molecular pathogenesis of these diseases.

The bacteriostatic effects of high-intensity ultrasonic treatment (HIU) on Bacillus subtilis vegetative cells were evaluated, and the related mechanisms were explored using quantitative proteomics. The bacteriostatic effect of HIU on B. subtilis was proportional to the ultrasound treatment time and power, and the number of cultivable B. subtilis cells was decreased by approximately one log (at 270 W for 15 min) or half log (at 90 W for 25 min or 360 W for 5 min). Scanning electron microscopy images and gel electrophoresis results showed that HIU caused the destruction of the cell structure and intracellular protein leakage. In addition, HIU treatment at 270 W for 15 min resulted in the greatest decrease (84.22%) in intracellular adenosine triphosphate (ATP) content. The quantitative proteomic analysis showed that B. subtilis resisted the stress of HIU treatment by regulating the key proteins in physiological activities related to membrane transport (ATP-binding cassette [ABC] transporter), signal transduction (the two-component system), and energy metabolism (the tricarboxylic acid [TCA] cycle). HIU-induced physical damage, stress, and metabolic disorders were the main causes of the bacteriostatic effects on B. subtilis. These findings provide a foundation for the subsequent optimization and potential applications of HIU inactivation of B. subtilis.

Plantago (Plantaginaceae) is an herbal plant, which is used in folk medicine, functional food, and dietary supplement products. Recent pharmacological and phytochemical studies have shown that polysaccharides isolated from Plantago have multiple medicinal and nutritional benefits, including improve intestinal health, hypoglycemic effect, immunomodulatory effect, etc. These health and pharmacological benefits are of great interest to the public, academia, and biotechnology industries. This paper provides an overview of recent advances in the physicochemical, structural features, and biological effects of Plantago polysaccharides and highlights the similarities and differences of the polysaccharides from different species and in different parts, including leaves, seeds, and husks. The scientific support for its use as a prebiotic is also addressed. The purpose of this review is to provide background as well as useful and up-to-date information for future research and applications of these polysaccharides.