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Secretory phospholipase A2s (sPLA2s) are found in a wide range of organisms from bacteria to higher plants and animals and are involved in varied and cellular processes. However, roles of these enzymes in microbial pathogens remain unclear. Here, an sPLA2 (BbPLA2) was characterized in the filamentous insect pathogenic fungus, Beauveria bassiana. BbPLA2 was exclusively expressed in insect hemolymph‐derived cells (hyphal bodies), and its expression was induced by insect‐derived nutrients and lipids, and nutrient starvation. High levels of secretion of BbPLA2 were observed as well as its distribution in hyphal body lipid drops (LDs). Overexpression of BbPLA2 increased the ability of B. bassiana to utilize insect‐derived nutrients and lipids, and promoted LD accumulation, indicating functions for BbPLA2 in mediating LD homeostasis and assimilation of insect‐derived lipids. Strains overexpressing BbPLA2 showed moderately increased virulence, including more efficient penetration of the insect cuticle and evasion of host immune responses as compared to the wild type strain. In addition, B. bassiana‐activated host immune genes were downregulated in the BbPLA2 overexpression strain, but upregulated by infections with a ΔBbPLA2 strain. These data demonstrate that BbPLA2 contributes to LD homeostasis, assimilation of insect‐derived lipids, and repression of host immune responses. [ABSTRACT FROM AUTHOR]

Summary: The effects of cellulose microfibres (CMFs, Average size: 100 ± 5 μm) and cellulose nanofibres (CNFs, Average size: 60 ± 3 nm) on the properties of myofibrillar protein (MP) gels from duck breast meat were studied. The results demonstrated that CMFs and CNFs were mostly connected to MP by non‐covalent bonds, the diffusion and cross‐linking of MP molecules was promoted, and a denser and more complete gel network was formed. With the increases of CMFs and CNFs concentration (0–10%), the hardness was increased by 13.15% and 19.78% for CMFs10% and CNFs10% gels, respectively, and the elasticity was increased by 40% and 80%, respectively. At the same concentration (0–10%), the increase in gel hardness, viscoelasticity and immobilised water content was greater in the CNFs‐MP group than in the CMFs‐MP group. The CNFs‐MP group had a tighter gel network, and CNFs had a better potential to improve the gelation performance of MP. [ABSTRACT FROM AUTHOR]

Summary: The low‐field nuclear magnetic resonance and Fourier transform infrared spectroscopy technique were carried out to evaluate the relationship between hydration characteristics and proteins structure in different stages pork of meat batters. The results showed that T21 increased throughout the process and the change of T22 and P21 was easily impacted by water, and the alternation of secondary structure was mostly impacted by salt; P21 was negatively correlated with the content of β‐sheet (r = −0.862), and positively correlated with the content of α‐helix (r = 0.933), β‐turn (r = 0.871) and random coil (r = 0.677), which meant there was some relationship between secondary structure and water distribution and migration. This research will provide theoretical support for the processing and production of meat products. [ABSTRACT FROM AUTHOR]

In the present study, the synergetic effect and mechanism of ultrasound (US) and slightly acidic electrolyzed water (SAEW) on the inactivation of Escherichia coli (E. coli) were evaluated. The results showed that US combined with SAEW treatment showed higher sanitizing efficacy for reducing E. coli than US and SAEW alone treatment. US and US combined with SAEW treatments resulted in smaller particle size of E. coli compared to the control and SAEW treatment. In addition, US combined with SAEW treatment induced the highest potassium leakage. However, the highest protein leakage was recorded in US treatment. Moreover, scanning and transmission electron microscopy analysis revealed that the greatest damage of the appearance and ultrastructure of E. coli was achieved after US combined with SAEW treatment. The synergetic effect was also confirmed by CLSM analysis. Fluorescence spectroscopy suggested that treatments of US, SAEW, and US combined with SAEW changed protein conformation of E. coli. Overall, the present study demonstrated that the sterilization mechanism of US combined with SAEW treatment was decreasing the particle size and disrupting the permeability of cell membrane and the cytoplasmic ultrastructure as well as changing protein conformation of E. coli. [ABSTRACT FROM AUTHOR]

In the present study, we investigated the characteristics of chicken meat fermented with Penicillium nalgiovense and Penicillium chrysogenum. Hardness and springiness gradually decreased, while gumminess gradually increased during fermentation. Fermentation with P. chrysogenum led to higher hardness and lower gumminess than fermentation with P. nalgiovense. Fermentation with two molds resulted in similar microstructure, such as granule formation and fractured myofibril. The highest percentage of secondary structure was ɑ-helix, and tyrosine residues were buried after fermentation. P. nalgiovense-fermented samples contained more bound water, lower relative content of alkanes, and higher relative content of aldehydes than P. chrysogenum-fermented samples. [ABSTRACT FROM AUTHOR]

Summary: In this study, the influence of ripening with Penicillium roqueforti on texture, microstructure, protein structure, water mobility and volatile flavour compounds of chicken breast meat was investigated. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) images showed that the granule formed and chicken myofibril fractured after ripening. Reduction in α‐helix and increases in β‐sheet structure content accompanied by decrease in hardness and springiness and increase in gumminess were found in ripened chicken breast meat. Low field nuclear magnetic resonance (LF‐NMR) revealed that increasing intra‐myofibrillar water and decreasing extra‐myofibrillar water resulted in the higher water‐holding capacity after ripening with P. roqueforti. In addition, chicken breast meat ripened with P. roqueforti contained more volatile flavour compounds, in particular aldehydes. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of storage temperatures and time on discoloration and oxidation of prepared chicken breast with paprika oleoresin. Freshly prepared chicken breast containing paprika oleoresin was stored at −2, −10, −18°C, and an oscillating temperature between −10 and −18°C (−10/−18°C). A significant decrease in redness was detected at −2, −10, and −10/−18°C. The lowest TBARS values and carbonyl contents were observed in the samples stored at −18°C for 5 weeks. Also, the values of sulfhydryl groups gradually decreased with the increase in storage temperatures and duration. The results suggest a positive correlation between the loss of redness and oxidation in all samples. The findings indicated that the discoloration and oxidation of prepared chicken breast added with paprika oleoresin were inhibited significantly when stored at −18°C. [ABSTRACT FROM AUTHOR]

To improve quality and safety of fermented sausages, Lactobacillus pentosus isolated from kimchi was first used to partial replacement of sodium nitrite in sausages preparation. The study illustrated that the strain exhibited the ability of synthesis of nitrosylmyoglobin (Mb‐NO) due to the presence of nitric oxide synthase (NOS) and metmyoglobin (MetMb) reductase and possible generation mechanism of Mb‐NO was proposed. More importantly, the strain could prevent sausages from corruption due to its antibacterial ability. Furthermore, the strain could degrade nitrite and resist against lipid oxidation and protein decomposition. Texture and color of the sausages were superior to the controls. Hence, L. pentosus has great potential to partially substitute nitrite in sausages for its unique ability of producing NO‐Mb and antibacterial activity. The combination of L. pentosus and low levels of sodium nitrite addition would be a new significant strategy to improve the quality and safety of the fermented sausages. Practical applications: Results support the possibility of reducing sodium nitrite concentration in fermented sausages by inoculation with Lactobacillus pentosus in which provided superior color‐cured, microbial stability, and oxidation stability. The combination of L. pentosus and low levels of sodium nitrite addition can be applied by a simple process during processing which facilitates their use in meat industry. [ABSTRACT FROM AUTHOR]