Green synthesis of antibacterial metal oxide nanoparticles is attractive for develop novel antibacterial agents. In this study, probiotic strain Lactobacillus plantarum ZDY2013 fermentation liquid (LFL) was utilized for the synthesis of zinc oxide nanoparticles (called as LFL-ZnO) via an ultrasound-microwave-facilitated procedure. SEM and TEM show the synthesized LFL-ZnO with a spherical morphology that are surrounded by LFL. Zeta potential and hydrodynamic sizes were − 25.533 ± 0.205 mV and 537.5 nm by dynamic light scattering (DLS) analyzer, respectively. X-ray diffraction (XRD) results revealed the hexagonal wurtzite structure of LFL-ZnO with a crystallite size of 41 nm. Fourier transform infrared (FTIR) spectrum and thermal gravimetric (TG) curve showed the structure differences between H-ZnO (synthesized by ddH 2 O instead of LFL) and LFL-ZnO. In addition, LFL-ZnO significantly inhibited the growth of methicillin-resistant Staphylococcus aureus (MRSA) with MIC = 100 μg/mL. The possible antibacterial mechanisms may be attributed to LFL-ZnO release a high concentration of Zn 2+ inducing the destruction of bacterial cell integrity resulting in the leakage of protein and reducing sugars. Meanwhile, CLSM results demonstrate the generation of reactive oxygen species (ROS) by LFL-ZnO is another important antibacterial mechanism. The synthesized LFL-ZnO has broad potential to be developed in pharmaceutics as an effective antimicrobial nanomaterial .
This study demonstrated the influences of ultrasound-assisted multilayer Pickering double emulsion capsules on the pasteurization and gastrointestinal digestive viability of probiotic (L. plantarum) strain liquid. Firstly, the role of ultrasonic homogenization on the morphology of W 1 /O/W 2 double emulsions were studied. The double emulsion formed by ultrasonic intensity at 285 W had a single and narrow distribution with smallest droplet size. The double emulsion particles were then coated with chitosan(Chi), alginate (Alg), and CaCl 2 (Ca). The multilayer emulsion after pasteurization and gastrointestinal digestion both had the highest viability at 5 coating layers, but its particle size (108.65 μm) exceeded the limit of human oral sensory (80 μm). It could be noted that the deposition of 3–4 layers of coating had similar activity after pasteurization/GIT digestion. And droplets with 3 layers of coating were the minimum and most available formulation for encapsulated probiotics ( L. plantarum ). Hence, the results suggest that the use of ultrasound-assisted multilayer emulsions encapsulated with probiotics in granular food and pharmaceutical applications is a promising strategy.
Rosa roxburghii Tratt fruits (RRT) exhibit extremely high nutritional and medicinal properties due to its unique phytochemical composition. Probiotic fermentation is a common method for processing fruits. Variations in the non-volatile metabolites and bioactivities of RRT juice caused by different lactobacilli are not well understood. Therefore, we aimed to profile the non-volatile components and investigate the impacts of L. plantarum fermentation (LP) and L. paracasei fermentation (LC) on RRT juice (the control, CG). There were both similarities and differences in the effects of LP and LC on RRT juice. Both of the two strains significantly increased the content of total phenolic, total flavonoid, and some bioactive compounds such as 2-hydroxyisocaproic acid, hydroxytyrosol and indole-3-lactic acid in RRT juice. Interestingly, compared with L. paracasei , L. plantarum showed better ability to increase the content of total phenolic and these valuable compounds, as well as certain bioactivities. The antioxidant capacity and α-glucosidase inhibitory activity of RRT juice were notably enhanced after the fermentations, whereas its cholesterol esterase inhibitory activity was reduced significantly. Moreover, a total of 1466 metabolites were identified in the unfermented and fermented RRT juices. There were 278, 251 and 134 differential metabolites in LP vs CG, LC vs CG, LC vs LP, respectively, most of which were upregulated. The key differential metabolites were classified into amino acids and their derivatives, organic acids, nucleotides and their analogues, phenolic acids and alkaloids, which can serve as potential markers for authentication and discrimination between the unfermented and lactobacilli fermented RRT juice samples. The KEGG enrichment analysis uncovered that metabolic pathways, purine metabolism, nucleotide metabolism and ABC transporters contributed mainly to the formation of unique composition of fermented RRT juice. These results provide good coverage of the metabolome of RRT juice in both unfermented and fermented forms and also provide a reference for future research on the processing of RRT or other fruits.
危险品化学品经营许可证（带存储）