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Bacterial cellulose (BC) was used as a reinforcing agent, citric acid (CA) as a cross-linking agent, and CMC@AgNPs as antibacterial nanomaterials, in which CMC@AgNPs were reduced from AgNO

Cultured meat (CM) production has emerged as a breakthrough technology for the global food industry, with the potential to reduce challenges associated with environmental sustainability, global public health, animal welfare, and competition for food between humans and animals. The muscle stem cell lines currently used for CM production cannot be passaged in vitro for extended periods of time. Here, we successfully developed a directional differentiation system of porcine pregastrulation epiblast stem cells (pgEpiSCs) with stable cellular features and achieved serum-free myogenic differentiation of the pgEpiSCs. The pgEpiSCs-derived skeletal muscle progenitor cells and skeletal muscle fibers show typical muscle cell characteristics and display skeletal muscle transcriptional features during myogenic differentiation. Importantly, we further established a three-dimensional differentiation system for shaping cultured tissue by screening plant-based edible scaffolds of non-animal origin, followed by the generation of pgEpiSCs-derived CM. These advances provide a novel technical approach for the development of CM.

Cell cultured meat (CCM) production is an innovative technology that does not depend on livestock farming practices to produce meat. The construction of structured CCM requires a three-dimensional (3D) scaffold to mimic the extracellular matrix to provide mechanical support for the cells. Furthermore, the 3D scaffolds should be edible and have good biocompatibility and tissue-like texture. Here, we demonstrated a 3D edible chitosan‑sodium alginate-collagen/gelatin (CS-SA-Col/Gel) scaffold that can support the adhesion and proliferation of porcine skeletal muscle satellite cells, culminating in the construction of a structured CCM model. The 3D edible scaffolds were prepared by freeze-drying using electrostatic interactions between chitosan and sodium alginate. Initially, the physicochemical properties and structural characteristics of different scaffolds were explored, and the biocompatibility of the scaffolds was evaluated using the C2C12 cell model. The results showed that the 2-CS-SA-Col

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.

Effects of sweetener neomethyl hesperidin dihydrochalcone (NHDC) on the gelation properties of myofibrillar protein (MP) at 0.2 M and 0.6 M NaCl were investigated. The results showed that addition of NHDC did not obviously change the cooking loss and strength of MP gels at 0.2 M NaCl. Whilst at 0.6 M NaCl, addition of high doses of NHDC (50-100 µM/g) remarkably increased cooking loss and decreased strength of MP gels. The expanded MP enhanced the interactions between NHDC and MP, leading to aggregation of MP as evidenced by the increasing particle size and the reducing solubility. The MP aggregates impeded hydrophobic interactions and disulfide bonds crosslinking in the gelation process, thereby damaged the gelation properties of MP at 0.6 M NaCl. This was supported by the poor network of MP gels observed by SEM. In the end, molecular docking elucidated the main types of interaction at molecular level, including hydrogen bonding and hydrophobicity. The results would provide guidance for NHDC as a potential sweetener in meat products.

Great challenges remain in the effective control of irregular and incompressible deep wound bleeding and the promotion of wound healing after bacterial infection. In this study, cryogels were prepared using an ice template based on chitosan (CS), oxidized gallic acid (OGA) and hemin (HE), which are all green edible materials. The cryogels exhibit rapid blood-triggered shape recovery and a high swelling ratio. The cryogels with 5 mg mL

The effect of quercetin on chicken breast muscle tenderness and the associated mechanism were investigated. The results indicated that quercetin significantly decreased the shear force and increased the myofibril fragmentation index (MFI). Haematoxylin-eosin-stained images showed that the internal structure of myofibril bundles in the quercetin-treated group was obviously degraded. Transmission electron microscopy showed that the myofibril structure, especially the M-line and A-band, was seriously degraded after quercetin treatment. Furthermore, quercetin treatment increased caspase-3 activity and the Bax/Bcl-2 ratio. The intensity of BiP, XBP1 and p-IRE1/IRE1 ratio increased significantly, and caspase-12 was activated. In addition, quercetin induced the transition from LC3I to LC3II and increased the expression of ATG7 and Beclin-1. The PI3K/Akt/mTOR signalling pathway was involved in the induction of autophagy and apoptosis by quercetin. These results indicated quercetin can promote meat tenderization, and activate apoptosis and autophagy pathways during post-mortem ageing.

In this study, the CS-DAS aerogels were prepared using chitosan (CS) crosslinked by dialdehyde starch (DAS), with the best absorption and mechanical properties at the weight ratio of CS to DAS being 7:3. The copper nanoparticles (CuNPs) were first prepared by green reduction method, then encapsulated by liposomes (Lip-CuNPs) for controlling their sudden release. The antibacterial aerogels (CD/Lip-CuNPs) were developed by incorporating the Lip-CuNPs into the aerogel (7:3). The porous network structure of aerogels realized the further gradual release of CuNPs. The CD/Lip-CuNPs aerogels had good antimicrobial properties, which could preserve fresh pork for 14 d at 4 °C without spoilage. Moreover, the CuNPs migrated from the aerogels into fresh pork was at a safe level of 3.38 mg/kg after 14 d at 4 °C. The obtained antibacterial CD/Lip-CuNPs aerogels had the potential for extending the shelf life of fresh meat.

Nano-bacterial cellulose (BC), as a reinforcing agent, was used to prepare the agar-based edible films. Effects of BC content (0, 3, 5, 8 and 10%, wt% based on the agar) on the rheological properties of film-forming solution (FFS), and on structure, morphology, crystallinity, and thermal properties of films were investigated. Results of rheological and FTIR analyses revealed that interactions between BC and agar were formed through hydrogen bonds. The crystallinity and the thermal stability of films were improved by addition of BC analyzed by XRD and TGA, respectively. Compared with high BC concentrations (8–10%), a good dispersion of BC at low concentrations (3–5%) in the films was observed by SEM. Moreover, BC addition (10%) significantly decreased moisture content (MC), water solubility (WS) and water vapor permeability (WVP) by 60.4%, 13.3% and 25.7%, respectively. The tensile strength (TS) of films increased from 22.10 to 44.51 MPa after addition of BC (0–10%), whereas the elongation at break (EAB) initially increased with increasing BC concentrations (0–5%), and then decreased with further addition of BC (8–10%). Consequently, agar-based edible films reinforced by moderate nano-BC have the potential as a packaging film for food products.

The objective of this study was to investigate the ability of thermally degraded gelatin to bind aroma compounds such as nonanal, 2-heptanone, 1-octen-3-ol, hexyl acetate and 2-pentyl furan. Binding ability was strongly affected by changes in thermal-degradation products, the structure and surface hydrophobicity of proteins during heating (1–4 h), through analyzing the results of GC-MS, SDS-PAGE, LC-MS/MS, free amino acid, circular dichroism spectra, Fourier transform infrared (FT-IR) spectroscopy, zeta potential, and surface hydrophobicity. Binding ability of gelatin to aroma compounds increased from 12-14% to 29–35% after heating for 4 h. During the first 1 h of heating, there was no significant increase in surface hydrophobicity due to the effects of degradation and unfolding of protein and protein aggregation, thus the increase in zeta potential and free proline caused by gelatin degradation was likely responsible for the increase in binding ability through electrostatic interactions and hydrogen bonding, respectively. After heating for 2–3 h, unfolding and degradation of gelatin played a leading role in exposure of more hydrophobic amino acids on the protein surface, suggesting an enhancement of binding ability due to hydrophobic interaction. Moreover, effects of zeta potential, exposure of more proline on the interface, and increase in free proline caused by protein degradation could also enhance the affinity of gelatin to flavor compounds. After heating for 4 h, exposure of more hydrophobic amino acids and free proline continued to increase flavor-binding ability, although zeta potential decreased. The results provided insight into improving flavor profile of meat matrix.

This study investigated the effects of transglutaminase (TGase) on the properties of myofibrillar protein (MP) and its heat-induced gels under malondialdehyde (MDA)-induced oxidation. The physicochemical characteristics, protein aggregation and rheological properties of MP were assessed. The gelling behaviours of MP were analysed with measurements of gel strength, cooking loss, microstructure and secondary structure. Under varying degrees of MDA oxidation, the addition of TGase always led to changes in the tertiary structure, loss of free amine and thiol groups, crosslinking of the myosin heavy chain, and decreasing solubility. However, the effect of TGase on MP gel quality differed. At 6 mmol/L MDA, the addition of TGase reduced the quality of MP gels by increasing cooking loss. However, at 12 mmol/L MDA, TGase reduced both the cooking loss and gel strength.

Nowadays, natural antioxidants abundant in polyphenols have been widely used to substitute synthetic antioxidants in meat products. In general, high doses of natural antioxidants are required to provide comparative antioxidant effects as synthetic antioxidants. Noticeably, the qualities of meat products can be jeopardized due to interactions between polyphenols and myofibrillar proteins (MPs). In this study, methyl-β-cyclodextrin was used to increase the polyphenol loading amount by preventing interactions between polyphenols and proteins. Solubility, electrophoresis, fluorescence spectroscopy, and surface hydrophobicity analyses indicated that methyl-β-cyclodextrin could dose-dependently inhibit epigallocatechin-3-gallate-induced attacks on MPs under oxidative stress. Gel strength, cooking loss, confocal laser scanning microscopy, dynamic rheological testing, and Raman spectrum during gelation were further analyzed to investigate the effects of methyl-β-cyclodextrin on the qualities of epigallocatechin-3-gallate-treated emulsion gel. Methyl-β-cyclodextrin addition prevented modification of the secondary structure of MPs caused by epigallocatechin-3-gallate. In consequence, the gel and emulsifying properties of MPs were significantly improved. Moreover, β-cyclodextrins could partly inhibit oxidative attacks on MPs and thus increase their solubility. These results indicated that methyl-β-cyclodextrin addition effectively enhanced epigallocatechin-3-gallate loading capacity in meat products.

High levels of polyphenols can interact with myofibrillar proteins (MPs), causing damage to a MP emulsion gel. In this study, β-cyclodextrins were used to reduce covalent and non-covalent interaction between epigallocatechin-3-gallate (EGCG) and MPs under oxidative stress. The loss of both thiol and free amine groups and the unfolding of MPs caused by EGCG (80 μM/g protein) were significantly prevented by β-cyclodextrins, and the structural stability and solubility were improved. MP emulsion gel treated with EGCG (80 μM/g protein) had the highest cooking loss (68.64%) and gel strength (0.51 N). Addition of β-cyclodextrins significantly reduced cooking loss (26.24-58.20%) and improved gel strength (0.31-0.41 N) of MP emulsion gel jeopardized by EGCG under oxidative stress. Damage to the emulsifying properties of MPs caused by EGCG was significantly prevented by addition of β-cyclodextrins. β-cyclodextrins reduced interaction between EGCG and MPs in the order Methyl-β-cyclodextrin > (2-Hydroxypropyl)-β-cyclodextrin > β-cyclodextrin. In absence of EGCG, addition of β-cyclodextrins partly protected MPs from oxidative attack and improved its solubility. It is concluded that β-cyclodextrins does not markedly reduce the antioxidant ability of EGCG according to carbonyl analysis, and can effectively increase EGCG loading to potentially provide more durable antioxidant effect for meat products during processing, transportation and storage.

The effects of rosmarinic acid (RA) (12, 60 and 300 μM/g protein) on the textural properties and stability of oxidized myofibrillar protein (MP) emulsion gels were investigated. A low dose (12 µM/g) of RA significantly prevented the loss of thiol and e-NH2 groups and the unfolding of the oxidized MP. However, a high dose of RA (300 µM/g) covalently and non-covalently interacted with the MPs, which induced a significant loss of thiol and e-NH2 groups and aggregation of the MPs, causing decreased solubility, resulting in a poor three-dimensional emulsion gel network, and hence, higher cooking loss and lower gel strength. Moreover, the emulsifying properties of the MP emulsion gel were jeopardized by 300 µM/g RA. A high concentration of NaCl (0.6 M) enhanced the interaction between RA and MPs, increasing deterioration of the internal structure and leading to extremely unstable emulsifying properties of the MP emulsion gel.

Films with antioxidant activity were prepared by combining chitosan (CH) and epigallocatechin-3-gallate (EGCG) with nano-bacterial cellulose (BC) as a reinforcement agent. Results showed that BC addition improved the qualities of films jeopardized by EGCG. Fourier Transform Infrared (FTIR) spectroscopy analysis confirmed that there were intermolecular interactions among BC, CH and EGCG though hydrogen bonding. Consequently, BC addition increased the crystallinity and thermal stability of CH-BC5/10-EGCG15/30 films analyzed by X-ray diffraction (XRD) and thermogravimetric (TGA) analysis. BC addition also significantly decreased water solubility (WS), from 26.54% to 20.80%, increased tensile strength (TS), from 18.71 to 44.17MPa, and increased elongation at break (EAB), from 2.72% to 7.34%. Moreover, BC and EGCG had high affinity for each other, as BC addition lowered the release of EGCG from CH films with a higher ABTS radical scavenging ability. Therefore, BC can be used as a sustained release carrier of EGCG in antioxidant active films.

Bacteriocins are heat-stable, antimicrobial peptides produced by many organisms, including lactic acid bacteria (LAB). In this study, Lactobacillus casei (L. casei) was isolated from a traditional Chinese fermented vegetable ( Jiangshui Cai ). Among the isolates, L. casei was found to be inhibit the growth both Gram-positive and Gram-negative indicator strains. A tomato-based medium was optimized for the growth of L. casei , taking care to exclude constituents that might compromise bacteriocin purification. Purified bacteriocin from L. casei (Purified through Sephadex G-25, HiPrepQXL 16/10 column of AKTA, RPC column of AKTA and reverse phase HPLC) LiN333 showed antimicrobial activity after treatment at a wide range of temperatures (60, 80, 100, 121 °C) and pH levels (pH 3, 4, 5, 6, 7, 8, 9). LiN333 displayed antimicrobial ability against Gram positive and Gram negative pathogenic and antibiotic resistant bacteria, including Listeria . MALDI-TOF-MS determined that the molecular weight of LiN333 was 4890 Da. Scanning electron microscopy (SEM) was used to observed the mechanism of action of LiN333. The minimum inhibitory concentration against E. coli and S. aureus was 15 μg/ml. LiN333 shows potential application as a food preservative based on its mechanism of action and its stability across a range of pH values and temperatures.

Antioxidant properties and flavor characteristic profile of pomegranate wine during winemaking were investigated. The total phenol content and radical scavenging activity exhibited a slightly decrease in the end edge. Punicalagins and gallic acid were revealed to be the most abundant phenolic compounds, followed by ellagic acid and vanillic acid. These constituents were mainly responsible for the effective antioxidant capacity of pomegranate wine. The major changes of flavor qualities occurred in the initial stage, particularly 0-4day of fermentation. Fermentation significantly reduced the relative content of aldehydes, ketones, heterocyclic and aromatic compounds, but promoted the generation of esters and alcohols. This is the first time of using E-nose and E-tongue to monitor odour and taste changes in the brewing process of pomegranate wine. The study may provide a promising instruction for improving functional features and quality control of the pomegranate wine.

The objective of this study was to explore the oxidative modification induced by AAPH (2,2'-azobis (2-amidinopropane) dihydrochloride) on the microbial transglutaminase (MTGase) cross-linking reaction and gelling properties of silver carp myofibril protein (SCMP). Compared to AAPH treatment, MTGase addition resulted further changes of protein properties as evidenced by the decreasing free amino and thiol group content, the decreased secondary and tertiary structure, and the increasing storage modulus (G') and gel strength (P 0.05). The proper oxidation induced by AAPH (5 mM) promoted the glutamine-lysine and disulfide cross-linking due to MTGase (10 U/g). Therefore, the quality of the SCMP gel was improved with a good water-holding capacity (WHC), gel strength and G'. This results could lay a theoretical foundation for the development of silver carp surimi products with good quality. Chemical compounds: (2,2'-azobis(2-amidinopropane)dihydrochloride (PubChem CID:76344); O-Phthalaldehyde (PubChem CID:4807); 5,5'-Dithiobis(2-Nitrobenzoic Acid) (PubChem CID:6254); 8-Anilino-1-naphthalenesulfonic acid (PubChem CID:1369); Acrylamide (PubChem CID: 6579); β-Mercaptoethanol (PubChem CID: 1567); Sodium dodecyl sulfate (PubChem CID:3423265).

The effects of nonenzymatic glycation on the binding capacity of beef myofibrillar proteins (MP) to aldehyde flavour compounds were investigated. The binding capacity was significantly increased due to the partial unfolding and flexible secondary structure of the glycated MP. Unfolding played a dominant role in binding due to the prevention of protein aggregation by steric hindrance originating from glycation with glucose (Glu), while glycation with glucosamine (GluA) induced substantial aggregation due to cross-linking. Therefore, the MP glycated with Glu had a higher binding capacity for aldehyde flavour compounds compared to MP glycated with GluA. In a competitive binding system, the MP glycated with Glu had a higher binding capacity for long-chain aldehyde flavour compounds. However, the MP glycated with GluA had a higher binding capacity for short-chain aldehyde flavour compounds, which were more likely to interact with the binding sites shielded in the protein aggregate. Nonenzymatic glycation represents a potential method to enhance the flavour intensity of meat products with high-protein levels.

In this study, 1500 W, 40 kHz ultrasound was used to treat chicken muscle during 5 days of ageing after slaughter. Ultrasound treatment-induced typical apoptosis was applied to chicken muscle after slaughter. Our Western blot results showed that the key factors of the death receptor pathway in apoptosis fas, fas-L, and caspase-8 were activated during storage of the meat. Treatment with ultrasound significantly stimulated the activity of caspase-9, cytochrome c and tbid, and increased the ratio of bax/bcl-2 as shown by western blotting analysis. Transmission electron microscopy images showed ultrastructural damage to the mitochondria and nucleus that was morphologically characteristic of apoptosis during post-mortem ageing. All the treatments reduced the band intensity of desmin and caspase-3 during 5 days of meat ageing. The hematoxylin-eosin staining of muscle tissue structure showed that ultrasound treatment increased the gap between muscle fibre bundles. Ultrasonic treatment significantly reduced the shear force of chicken breast, which could improve the tenderness of the meat. The findings of this investigation revealed that ultrasound affected meat ageing via apoptosis and possibly activated myofibril degradation. We speculate that the morphological and biochemical changes relating to apoptosis have the potential to contribute to the tenderization of meat.

Different techniques have been applied to alter myofibril protein (MP) structure, which further promotes protein-protein interactions and influencing the MP gelling characteristics. Influence of BslA from natto food (protein concentration, 30 mg mL-1 ; at 0.001, 0.005, 0.01, 0.05 and 0.1 g kg-1 ) on the characteristics of MP gel of chicken breast was investigated.; Results: Results show that cooking loss significantly (P < 0.05) decreased with increased percentage of BslA. Hardness of MP gel did not significantly change at 0.01 g kg-1 BslA. Differential scanning calorimetry disclosed that MP was modified by the addition of BslA. Moreover, BslA produced a high value of storage modulus (G') and low value of phase angle (tan δ) during heating, especially at 0.01 g kg-1 . Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis proved the formation of higher-molecular-weight polymers by developing non-disulfide covalent bonds between MP at 0.01 g kg-1 BslA. Surface hydrophobicity of the MP gel was decreased with increased percentage of BslA. Scanning electron microscopy confirmed the increasing number of uniform cavities of MP gel with the increased percentage of BslA.; Conclusion: Addition of 0.01 g kg-1 BslA significantly improved the water holding capacity and rheological properties of MP by developing non-disulfide covalent bonds. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.

Biocomposite films were manufactured by combining protein extracted from buckwheat distiller’s dried grains with bacterial cellulose (BC). The film microstructures showed that BC is compatible with protein matrix and endows the film with high rigidity. Differential scanning calorimetry (DSC) showed that BC can promote thermal stability of the composite films. BC promoted the transition from a Newtonian to a non-Newtonian fluid and the shear thinning behavior of protein-BC solution. Fourier Transform Infrared (FTIR) spectroscopy showed the main functional groups’ absorption peaks shifted to lower wavenumbers. Results of both FTIR and viscosity analysis proved the formation of intermolecular interactions through hydrogen bonds. These bonds affected film characteristics such as moisture content (MC), water solubility (WS), and water vapor permeability (WVP), which decreased with addition of BC. The WVP (6.68 ± 0.78 − 5.95 ± 0.54 × 10−10 g m/Pa s m2) of the films were lower than other protein films. Tensile strength (TS) values of films containing 1.8% and 2.0% BC (14.98 ± 0.97 and 15.03 ± 2.04 MPa) were significantly higher than that of pure protein films (4.26 ± 0.66 MPa). Combination of proteins extracted from a waste product and BC led to composite films with low water vapor permeability and excellent mechanical properties.

Development of biodegradable food packaging using biomass based materials derived from agricultural wastes has been a trend in recent years. The biopolymer films were prepared using 3% and 5% (w/w) potato peel (PP) powder. Bacterial cellulose (BC) (0, 5, 10 and 15% based on PP powder) was added as a reinforcement agent. The scanning electron microscopy (SEM) revealed that 10% BC had a promising compatibility with the PP matrix. X-ray diffraction (XRD) and thermogravimetric analysis (TGA) showed that the crystallinity and the thermal stability of films did not change with BC addition. Fourier transform infrared spectroscopy (FTIR) indicated the hydrogen bonding interactions between the PP matrix and BC in the films. BC addition significantly improved the tensile strength (TS), but reduced their water vapor permeability (WVP), oxygen permeability (OP) and moisture content (MC) of the PP films. Addition of curcumin further increased the antioxidant properties of the PP films. The PP films with 1-5% curcumin significantly reduced lipid oxidation in the fresh pork during storage with lower malondialdehyde (MDA) content.

Impact of malondialdehyde (MDA) and (−)-Epigallocatechin-3-gallate (EGCG) on gelling properties of myofibrillar proteins (MPs) was investigated. Addition of 6 mM MDA enhanced molecular interactions of proteins, thus the strength and elastic modulus (G′) of gel were improved. EGCG addition aggravated gel quality deterioration due to further modification of MPs induced by EGCG. Addition of 12 mM MDA jeopardized gel quality according to the increasing of strength and G′, but the decreasing of water-holding capacity (WHC), and the collapse of microstructure. Nevertheless, EGCG reacted with MDA forming EGCG-MDA adducts, hence improved gel quality, which was supported by the decreasing of strength, but the increasing of WHC, and the repaired microstructure of gel at 12 mM MDA. Addition of 24 mM MDA severely jeopardized gel quality, which became even worse due to EGCG addition. This work is helpful to understand the impact of MDA and polyphenols on the gel-forming capacity of MPs.

Resveratrol supplementation has been reported to improve markers of vascular function, but poor bioavailability of the parent compound is thought to limits its use. In this study, we compared the effects of a resveratrol-arginine conjugate (ResArg) to trans-resveratrol (trans-Res), the standard form used in supplements, on measures of microvascular function 1 h and 2 h after intake. Postmenopausal women were assigned to consume 90 mg of resveratrol as either ResArg or t-Res, in a double-blind, randomized, crossover design, at least one week apart. Microvascular function was assessed by peripheral arterial tonometry, and calculated as the reactive hyperemia index (RHI) and the Framingham RHI (fRHI); at 1 h, platelet reactivity, plasma resveratrol and nitrate/nitrite levels were also measured. A significant increase in fRHI was observed 1 h after intake of ResArg compared to trans-Res. Significant reductions in platelet reactivity were noted 1 h after ResArg intake, but not for trans-Res. Plasma resveratrol levels were increased 30 and 60 min after the consumption of both ResArg and t-Res. The results suggest a more rapid and pronounced response from ResArg than trans-Res on certain markers of vascular function.

The stability of cured meat products is increased by the protection of its proteins from oxidation by sodium nitrite (NaNO2) during processing. This study investigated the effects of NaNO2 (0, 50, 100, 200, and 400 mg/kg) on the physiochemical and structural characteristics of myofibrillar protein (MP) in raw and cooked ham. The NaNO2 showed a dose-dependent antioxidant effect, by inhibiting carbonyl formation, dityrosine formation, and denaturation of MP, and a nitrosative effect, through the formation of 3-Nitrotyrosine (3-NT). The 3-NT content within MP of raw ham had distinct negative correlations with sulfhydryl content and surface hydrophobicity. The 3-NT content within MP of cooked ham had significantly negative correlations with carbonyl, sulfhydryl content and turbidity and had significantly positive correlations with disulfide content. These results indicated that 3-NT may be a potential marker for protein oxidation in raw and cooked cured meat products.

The quality of meat products is influenced by protein oxidation. Understanding the effects of antioxidant polyphenols and oxidizing lipoperoxides on myofibrillar proteins is essential for controlling the quality of meat products. This study was designed to investigate the epigallocatechin-3-gallate (EGCG)-mediated formation of myofibrillar protein emulsion gels under malondialdehyde (MDA)-induced oxidative stress. Low MDA concentrations (3 and 6 mM) improved the water-holding capacity, strength, elasticity, and emulsifying properties of gels due to the enhanced protein-protein interactions via MDA. The addition of EGCG reduced the overall properties of the emulsion gel due to further modification of the proteins. At a high concentration of MDA (12 mM), there was excessive cross-linking and unfolding of myofibrillar proteins, which led to a compact gel structure, and reduced the overall properties of the gel. In this situation, the addition of EGCG protected myofibrillar proteins from modifications induced by MDA and improved the quality of emulsion gels.

The influences of nano-bacterial cellulose (Nano-BC)/soy protein isolate (SPI) complex gel on the textural, rheological, and sensory properties of the ice cream model were investigated. Nano-BC/SPI mixtures with different ratios (Nano-BC:SPI, 1:20, 1:15, 1:10, and 1:5 w/w) were prepared with constant total solid content (16%). Compared with pure SPI, the thermal stability, textural, rheological and emulsifying properties of nano-BC/SPI mixtures were improved. Microstructure of nano-BC/SPI complex gels showed that low doses of nano-BC (1:20, 1:15, and 1:10) had good compatibility with SPI matrix according to images of confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Nano-BC/SPI (1:20) had the most similar textural properties to the cream. When 20% of nano-BC/SPI (1:20) mixture was added into ice cream as the cream substitute, the anticipated ice cream with low calorie, melting resistance, and good textural properties was achieved.

In this study, comprehensive characterization and drying methods on properties of bacterial cellulose were analyzed. Bacterial cellulose was prepared by Gluconacetobacter hansenii CGMCC 3917, which was mutated by high hydrostatic pressure (HHP) treatment. Bacterial cellulose is mainly comprised of cellulose Iα with high crystallinity and purity. High-water holding and absorption capacity were examined by reticulated structure. Thermogravimetric analysis showed high thermal stability. High tensile strength and Young's modulus indicated its mechanical properties. The rheological analysis showed that bacterial cellulose had good consistency and viscosity. These results indicated that bacterial cellulose is a potential food additive and also could be used for a food packaging material. The high textural stability during freeze-thaw cycles makes bacterial cellulose an effective additive for frozen food products. In addition, the properties of bacterial cellulose can be affected by drying methods. Our results suggest that the bacterial cellulose produced from HHP-mutant strain has an effective characterization, which can be used for a wide range of applications in food industry.

The dose-dependent effects of (-)-epigallocatechin-3-gallate (EGCG; 0, 100, or 1000 ppm) on the textural properties and stability of a myofibrillar protein (MP) emulsion gel were investigated. Addition of EGCG significantly inhibited formation of carbonyl but promoted the loss of both thiol and free amine groups. Addition of EGCG, particularly at 1000 ppm, initiated irreversible protein modifications, as evidenced by surface hydrophobicity changes, patterns in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and differential scanning calorimetry. These results indicated that MP was modified by additive reactions between the quinone of EGCG and thiols and free amines of proteins. These adducts increased cooking loss and destabilized the texture, especially with a large EGCG dose. Confocal laser scanning microscopy and scanning electron microscopy images clearly indicated the damage to the emulsifying properties and the collapse of the internal structure when the MP emulsion gel was treated with a large EGCG dose. A high concentration of NaCl (0.6 M) improved modification of MP and increased the rate of deterioration of the internal structure, especially with the large EGCG dose (1000 ppm), resulting in an MP emulsion gel with extremely unstable emulsifying properties.

Different techniques have been applied to alter myofibril protein (MP) structure, which further promotes protein-protein interactions and influencing the MP gelling characteristics. Influence of BslA from natto food (protein concentration, 30 mg mLResults show that cooking loss significantly (P0.05) decreased with increased percentage of BslA. Hardness of MP gel did not significantly change at 0.01 g kgAddition of 0.01 g kg

The thermal properties of cured meat are important for determining storage life and nutritional quality. However, few studies have focused on the thermal properties of dry-cured pork, particularly in relation to salt level and type. In order to study the thermal properties of dry-cured pork, we used differential scanning calorimetry (DSC) to evaluate the net heat energy (enthalpy, � H), onset (Tonset), and maximum (Tmax) temperatures of different pork cuts salted with mixtures of chloride (NaCl and KCl) salts within the curing and ripening temperature range. Within the curing temperature range (− 5t o 20°C), the Tonset, Tmax ,a ndH of cured meat treated with different NaCl:KCl mixtures were generally lower than for fresh meat, which indicates that the addition of NaCl or KCl can reduce the melting of lipids and water (especially lipids), in different pork cuts. Within the ripening temperature range (5 to 50 °C), heat absorption peaks in belly and leg cuts were between 29 and 33 °C. However, no obvious heat absorption peak was found in loin cuts. Compared to non-KCl substitutions, a slightly higher KCl substitution could significantly (P < 0.05) enhanceH values of dry-cured belly and leg cuts. The likely cause of this phenomenon is that high KCl substitutions promote lipid oxidation (r = 0.98, for belly; r = 0.95, for leg cuts). Therefore, KCl substitution should be no more than 30% (wt/wt), especially for high lipid pork, to prevent excessive melting and oxidation of lipids during the dry-curing process.

Different effects of lamb and pork consumption on thyroid hormone levels and energy metabolism of rats were investigated. Three diets, a lamb meat diet (LD), a pork meat diet (PD) and control casein diet (CD) were isocaloric (15.5 kJ/g dry matters). Rats in the PD group had higher serum selenium concentrations ( P P P P P P P P P P P P

Glucosamine (GlcN) and microbial transglutaminase (Tgase) are used separately or together to improve the emulsifying properties of whey protein isolate (WPI). However, little is known about how the emulsifying properties change when GlcN residues are incorporated into WPI cross-linked by Tgase. We used Tgase as a biocatalyst to cross-link WPI in the presence of GlcN in a liquid system for 12 h at a moderate temperature (25°C). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analyses indicated that protein polymerization and GlcN conjugation occurred simultaneously, phenomena also supported by the loss of free amines (9.4–20.5%). Addition of 5 U Tgase/g protein improved the emulsifying properties of moderately cross-linked WPI polymers. The Tgase-treated WPI polymers had a larger particle size (∼2.6-fold) than native WPI, which may have reduced coalescence and flocculation in an oil-in-water emulsion system. However, the incorporation of GlcN residues into WPI, predominantly via enzymatic glycation, partly inhibited the cross-links between the WPI molecules catalyzed by Tgase, reducing the size of the WPI polymers 0.81- to 0.86-fold). Consequently, WPI+GlcN conjugates provided less stability to the emulsion. Moreover, high NaCl concentration (0.2 M) decreased the emulsifying properties of the WPI+GlcN conjugates by neutralizing negative electric charges in the glycoconjugates. However, the improved emulsifying properties of WPI cross-linked by Tgase may be useful in food processing at higher NaCl concentrations due to the formation of the thicker steric barrier at the oil-water interface.

PSE pork has a weaker texture than normal pork due to the denaturation by endogenous protease. Changes in the nutritional quality and characteristics of myofibrillar protein (MP) from PSE pork have been scarcely documented. MPs were isolated from both PSE (MPP) and normal pork (MPN) and were oxidized for 12h at 4°C by a hydroxyl radical generating system (10μM FeCl3, 100μM ascorbic acid, 0.1, 1, and 10mM H2O2). The MPP had less aggregation and looser structure with higher surface hydrophobicity. The MPP was also less polymeric, as evidenced by intenser bands on SDS-PAGE and fewer carbonyl-NH2 interactions. The MPP particles were of smaller size, caused by the endogenous protease and oxidation, and reached the critical concentration to enhance the solubility. The altered characteristics of MPP enhanced its in vitro digestion rate and overall digestibility. In addition, the in vitro digestion rate of MPN can be enhanced if the oxidative stress is strong enough (10mM H2O2).

The influence of NaNO2 content on protein oxidation and nitrosation was investigated in cooked sausages at different concentrations (0, 50, 100, 200 and 400 mg NaNO2/kg). Dependent on concentration, NaNO2 had both anti- and pro-oxidant effects on protein oxidation. The antioxidant effects of NaNO2 on the protein oxidation were evidenced by significantly lower carbonyl contents, higher free amines and lower surface hydrophobicities. The pro-oxidant effects of NaNO2 on protein oxidation resulted in a decrease of sulfhydryls and an increase of disulfide bonds. NaNO2 also improved the protein nitrosation inducing the formation of 3-nitrotyrosine (3-NT). Moreover, 3-NT had significant correlations with parameters of protein oxidation, indicating that 3-NT may be a possible marker for protein oxidation. Results of this study contribute to an understanding of the impact of NaNO2 on food quality and help to identify optimal formulations of cured meat products.

Cronobacter spp. are opportunistic pathogens that can cause serious diseases in neonates and infants via consumption of contaminated milk powder. To determine Cronobacter spp. contamination status, 632 samples, including 15 evaporated milk, 45 intermediate powder, 150 finished products, and 422 manufacturing environment samples, were collected from 3 goat milk powder factories in Shaanxi province, China, from July 2013 to April 2014. The recovered Cronobacter isolates were subtyped using pulsed-field gel electrophoresis to trace the potential dissemination routes during the whole production processing. Sixty-seven Cronobacter spp. isolates were recovered. The prevalence rates in manufacturing environment, intermediate powder, and finished products were 92.5, 6.0, and 1.5%, respectively. The predominant species were Cronobacter sakazakii (88.1%); no Cronobacter turicensis, Cronobacter condimenti, or Cronobacter dublinensis were detected. Sixty-seven Cronobacter isolates were grouped in 26 clusters by pulsed-field gel electrophoresis, and substantial genetic similarity was observed among isolates from different sampling sites in the same factory. Isolates in the main clusters were commonly recovered from intermediate powder, floor powder, and shoes. These data indicated that air, powder, and personnel movement were potential routes for Cronobacter dissemination, and manufacturing environment is the key control point for Cronobacter contamination.

In this study, comprehensive characterization and drying methods on properties of bacterial cellulose were analyzed. Bacterial cellulose was prepared by Gluconacetobacter hansenii CGMCC 3917, which was mutated by high hydrostatic pressure (HHP) treatment. Bacterial cellulose is mainly comprised of cellulose Iα with high crystallinity and purity. High-water holding and absorption capacity were examined by reticulated structure. Thermogravimetric analysis showed high thermal stability. High tensile strength and Young's modulus indicated its mechanical properties. The rheological analysis showed that bacterial cellulose had good consistency and viscosity. These results indicated that bacterial cellulose is a potential food additive and also could be used for a food packaging material. The high textural stability during freeze-thaw cycles makes bacterial cellulose an effective additive for frozen food products. In addition, the properties of bacterial cellulose can be affected by drying methods. Our results suggest that the bacterial cellulose produced from HHP-mutant strain has an effective characterization, which can be used for a wide range of applications in food industry.

In this investigation, ultrasonic treatments at a frequency of 40 kHz and power of 1,500 W made caspase-3 and calpain activities significantly higher in chicken muscle after slaughter during 5d storage (p