Overall quality changes and deterioration mechanism of fragrant rapeseed oils during 6-Month storage.

The strong-fragrant rapeseed oil (SFRO) is a popular rapeseed oil in China with a low refining degree only degumming with hot water, which remarkably affects its storage stability. The present study compared the overall changes of physical/chemical/nutrient quality of FROs at various temperatures, light wavelengths and headspace volumes. Results showed that red light (680 nm) had a most significant adverse effect on the overall quality of SFRO with the higher correlation coefficients to PV and TOTOX of 0.71 and 0.70, and lower correlation coefficients to chlorophyll and tocopherol of -0.95 and -0.53, respectively. Further studies revealed that red light accelerated the oxidation of fragrant rapeseed oils by degrading chlorophyll to initiate the photo-oxidation process and synthesize high amount of secondary oxidation products including aliphatic and aromatic oxidized compounds from linolenic acid. These findings provided a reference to control the deterioration of FROs by preventing the transmittance of red light.

Facile one-step synthesis of gold nanoparticles using Viscum album and evaluation of their antibacterial potential.

Nanostructure gold nanoparticles (Au NPs) are well-known biological active materials, synthesised under different environment-friendly approaches that has gained significant interest in the field of biomedicine. This study investigated a novel, fast, easy, cost-effective and the eco-friendly method to synthesise Au NPs from mediated Viscum album Linn plant extract, where the plant metabolites act as stabilising and reducing agents. The synthesised Au NPs were analysed by UV/Vis spectroscopy that gave strong signals and a sharp absorption peak at 545nm due to the presence of surface plasmon resonance (SPR) bands. In addition, energy dispersive X-ray spectroscopy (EDX) showed that strong signals of Au NPs appeared at 9.7 and 2.3keV, as the rays of light passed. X-ray diffraction recognised the crystalline material and provided information on the cell unit that the synthesised Au NPs are face-centreed cubic in structure. The diffraction of X-ray spectra showed intense peaks at 38.44°, 44.7°, 44.9° and 77.8°. The mediated V. album plant extracts and synthesised Au NPs were screened against gram-positive and gram-negative (Enterobacter , Salmonella typhi , Escheria coli and Bacillus subtilis ) bacterial strains, confirming their antibacterial potential. Au NPs showed strong antibacterial activity due to its unique steric configuration. Au NPs damaged bacterial cell membrane leading to the leakage of the cytoplasm and death of the cell.

ARTP mutation and adaptive laboratory evolution improve probiotic performance of Bacillus coagulans.

Bacillus coagulans is a thermophilic, facultative anaerobic, spore-forming Gram-positive bacterium, which is used as a probiotic in animal feed and human dietary supplements. In the present study, a bile-resistant thermophilic B. coagulans WT-03 strain was isolated and genetically identified. Atmospheric pressure room temperature plasma (ARTP)-induced mutation combined with adaptive laboratory evolution (ALE) was used to improve the probiotic performance of B. coagulans WT-03. After 15 s of ARTP mutation and 40 days of ALE culture, a mutant artp-aleBC15 was obtained and showed the improved tolerance to pH 2.5 and 0.3% bile salt with a survival rate of 22.4%. Further studies showed that the artp-aleBC15 mutant exhibited a relatively stable morphology, lower permeability, and higher hydrophobicity of cell membrane compared with the parent strain of B. coagulans. Additionally, artp-aleBC15 could maintain homeostasis with an intracellular pH of over 4.5 and had the altered contents of saturated fatty acids/unsaturated fatty acids in the cell membrane at pH 2.5. Our study proved that ARTP mutation combined with ALE is an efficient mutagenesis strategy to improve the probiotic performance of B. coagulans for potential industrial use.Key Points• A B. coagulans strain that can grow at 80 °C and 0.3% bile salt was screened.• ARTP combined with ALE effectively mutated B. coagulans WT-03.• B. coagulans artp-aleBC15 mutant showed an improved probiotic performance.• The mutant exhibited the lower permeability and altered fatty acid contents in the cell membrane.

Enhancing 2-Ketogluconate Production of Pseudomonas plecoglossicida JUIM01 by Maintaining the Carbon Catabolite Repression of 2-Ketogluconate Metabolism.

2-Ketogluconate (2KGA) is an organic acid that is important for pharmaceutical, cosmetic, and environmental applications. Pseudomonas plecoglossicida JUIM01 strain is an important industrial 2KGA producer in China. In this paper, we found that P. plecoglossicida JUIM01 could convert glucose to 2KGA extracellularly, and the formed 2KGA was subsequently consumed after glucose was exhausted during the fermentation process. Experiments of glucose and 2KGA supplementation during fermentation process revealed that, only when glucose was exhausted, the strain started to consume the product 2KGA. Then, the mechanism of this phenomenon was investigated at transcription and protein levels, and the results indicated that P. plecoglossicida JUIM01 possesses carbon catabolite repression of 2KGA metabolism by glucose. Next, increasing the supply of glucose could attenuate 2KGA consumption and enhance the 2KGA yield from glucose. Finally, fed-batch fermentation of P. plecoglossicida JUIM01 resulted in 205.67 g/L of 2KGA with a productivity of 6.86 g/L/h and yield of 0.953 g/g glucose. These results can provide references for the industrial fermentation production of 2KGA and other fermentation products.

Enhancement of quality retention of Grifola frondosa fruiting bodies by erythorbic acid treatment.

In this paper, the effects of erythorbic acid (EA) treatment with different concentrations on the quality of Grifola frondosa fruiting bodies stored at 4 °C for 27 days were studied by determining the changes in moisture content, weight loss, browning, electrolyte leakage, malondialdehyde (MDA), and nutritional compounds. The activities of polyphenoloxidase (PPO), cellulase and other antioxidant enzymes including superoxide dismutase (SOD), catalase, and peroxidase (POD) were also measured. Results showed that 0.1% EA-treated G. frondosa fruiting body maintained lower weight loss (< 6.0%, w/w), electrolyte leakage (< 45.8%), MDA (< 4.17 µmol kg-1), and higher moisture content (> 90.7%, w/w). Lower activities of PPO (< 72.64 × 103 U kg-1) and cellulase (< 189.86 × 103 U kg-1) in 0.1% EA-treated samples were observed compared with the other treatments. As a stereoisomer of ascorbic acid (AA), EA also could enhance SOD and POD activities of G. frondosa fruiting bodies. Our findings were the first time to evaluate the effect of EA on maintaining quality in G. frondosa fruiting bodies, and proved that low concentrations of EA (especially 0.1% EA, w/v) treatments were beneficial to preserve G. frondosa fruiting body with even higher efficiency than AA treatment. This study paved a foundation for the enhancement of quality retention of G. frondosa fruiting bodies.

Improved mycelia and polysaccharide production of Grifola frondosa by controlling morphology with microparticle Talc.

BACKGROUND: Mushroom showed pellet, clump and/or filamentous mycelial morphologies during submerged fermentation. Addition of microparticles including Talc (magnesium silicate), aluminum oxide and titanium oxide could control mycelial morphologies to improve mycelia growth and secondary metabolites production. Here, effect of microparticle Talc (45 µm) addition on the mycelial morphology, fermentation performance, monosaccharide compositions of polysaccharides and enzymes activities associated with polysaccharide synthesis in G. frondosa was well investigated to find a clue of the relationship between polysaccharide biosynthesis and morphological changes. RESULTS: Addition of Talc decreased the diameter of the pellets and increased the percentage of S-fraction mycelia. Talc gave the maximum mycelial biomass of 19.25 g/L and exo-polysaccharide of 3.12 g/L at 6.0 g/L of Talc, and mycelial polysaccharide of 0.24 g/g at 3.0 g/L of Talc. Talc altered the monosaccharide compositions/percentages in G. frondosa mycelial polysaccharide with highest mannose percentage of 62.76 % and lowest glucose percentage of 15.22 % followed with the corresponding changes of polysaccharide-synthesis associated enzymes including lowest UDP-glucose pyrophosphorylase (UGP) activity of 91.18 mU/mg and highest UDP-glucose dehydrogenase (UGDG) and GDP-mannose pyrophosphorylase (GMPPB) activities of 81.45 mU/mg and 93.15 mU/mg. CONCLUSION: Our findings revealed that the presence of Talc significantly changed the polysaccharide production and sugar compositions/percentages in mycelial and exo-polysaccharides by affecting mycelial morphology and polysaccharide-biosynthesis related enzymes activities of G. frondosa.

Chemical Compositions and Macrophage Activation of Polysaccharides from Leon's Mane Culinary-Medicinal Mushroom Hericium erinaceus (Higher Basidiomycetes) in Different Maturation Stages.

We studied the effect of the maturation stage on the chemical compositions and macrophage activation activity of polysaccharides from the culinary-medicinal mushroom Hericium erinaceus. Results showed that total polysaccharides increased, whereas protein content decreased with the maturation stage development of fruiting body. Nine polysaccharide fractions, 3 from each of the maturity stages IV (small fungal spine stage), V (mid-fungal spine stage) and VI (mature), were prepared using the gradient ethanol precipitation method. The polysaccharide fraction HP4A isolated from the maturating-stage (stage IV) fruiting body had a significant difference from the fractions HP5A (stage V) and HP6A (stage VI) in the molecular weight distribution and monosaccharide compositions. Immunostimulating tests revealed that the polysaccharide fraction HP6 isolated from the mature stage (stage VI) fruiting body presented higher macrophage activation activity. Our findings provided important information for the harvest and use of H. erinaceus with higher qualities and functional benefits.

Induction of apoptosis in SGC-7901 cells by polysaccharide-peptide GFPS1b from the cultured mycelia of Grifola frondosa GF9801.

The biological function of GFPPS1b, a novel polysaccharide-peptide isolated from cultured mycelia of Grifola frondosa GF9801, was well investigated. GFPS1b has anti-tumor activity and can significantly inhibit the proliferation of SGC-7901 cells, whereas slightly influences the growth of human normal liver cell line L-02. When treated with GFPS1b, SGC-7901 cells showed typical apoptotic morphological features such as the loss of villus and appearance of apoptotic bodies on the cell surface, volume reduction, and chromatin condensation, by scanning electron microscopy (SEM) and fluorescent microscopy (Hoechst 33342). The results of flow cytometry analysis and annexin V-PI assay showed that the SGC-7901 cell cycle was arrested in the G(2)/M phase, the subdiploid peak of DNA characteristic of apoptotic was also observed, and the apoptosis ratio was about 15.08%. DNA isolated from SGC-7901 cells cultured with GFPS1b showed a typical DNA 'ladders' of apoptosis in agarose gel electrophoresis. Further investigation results showed that the apoptotic machinery of SGC-7901 induced by GFPS1b was associated with drop in mitochondrial trans-membrane potential, upregulation of Bax, downregulation of Bcl-2, and activation of caspase-3. Our finding suggests that GFPS1b could suppress SGC-7901 cell growth and reduce cell survival via arresting cell cycle and inducing apoptosis of tumor cells.