Synthesis, characterization and anti-inflammatory activity of selenium nanoparticles stabilized by aminated yeast glucan.

Improving the dispersed stability of selenium nanoparticles (SeNPs) is the key to its application. In this study, yeast glucan with different degrees of amination (BNs) were used as stabilizers and capping agent to prepare dispersed SeNPs. The size, storage stability, and morphology of BNs/SeNPs were characterized. Results show that BNs/SeNPs presented positive potential and spherical morphologies with average particle size about 100-300 nm and kept stable at room temperature for a long time. The CCK-8 assay showed that BNs/SeNPs had significantly lower toxicity to RAW264.7 cells than SeNPs. Moreover, BNs/SeNPs could inhibit the generation of NO, IL-1ß and IL-6 effectively in RAW 264.7 macrophages induced by LPS, and down-regulate the mRNA transcription of iNOS, IL-1ß, IL-6 and chemokines (CCL2 and CCL5), indicating that BNs/SeNPs had good anti-inflammatory activity. Therefore, aminated yeast glucan could improve the stability and bioactivity of SeNPs simultaneously, which is a promising stabilizer for SeNPs.

Physicochemical and Functional Changes in Lotus Root Polysaccharide Associated with Noncovalent Binding of Polyphenols.

To promote the functional applications of lotus root polysaccharides (LRPs), the effects of noncovalent polyphenol binding on their physicochemical properties, as well as antioxidant and immunomodulatory activities, were investigated. Ferulic acid (FA) and chlorogenic acid (CHA) were spontaneously bound to the LRP to prepare the complexes LRP-FA1, LRP-FA2, LRP-FA3, LRP-CHA1, LRP-CHA2 and LRP-CHA3, and their mass ratios of polyphenol to LRP were, respectively, 121.57, 61.18, 34.79, 2359.58, 1276.71 and 545.08 mg/g. Using the physical mixture of the LRP and polyphenols as a control, the noncovalent interaction between them in the complexes was confirmed by ultraviolet and Fourier-transform infrared spectroscopy. The interaction increased their average molecular weights by 1.11~2.27 times compared to the LRP. The polyphenols enhanced the antioxidant capacity and macrophage-stimulating activity of the LRP depending on their binding amount. Particularly, the DPPH radical scavenging activity and FRAP antioxidant ability were positively related to the FA binding amount but negatively related to the CHA binding amount. The NO production of the macrophages stimulated by the LRP was inhibited by the co-incubation with free polyphenols; however, the inhibition was eliminated by the noncovalent binding. The complexes could stimulate the NO production and tumor necrosis factor-α secretion more effectively than the LRP. The noncovalent binding of polyphenols may be an innovative strategy for the structural and functional modification of natural polysaccharides.

Lotus Root Polysaccharide-Phenol Complexes: Interaction, Structure, Antioxidant, and Anti-Inflammatory Activities.

This research aimed to explore the interaction between lotus root polysaccharides (LRPs) and phenolic compounds, and to study the effects of phenolic binding on the structural and functional properties of LRPs. The influences of pH, temperature, and NaCl and phenol concentration on the binding ratio of gallic acid (GA)/epigallocatechin (EGC) to LRPs were evaluated. LRP-GA/EGC complexes with different phenolic binding amounts were then prepared and characterized via ultraviolet-visible (UV-Vis) and Fourier-transform infrared (FTIR) spectroscopy, and average molecular weight (MW) measurements. The results suggest that hydrogen bonds contributed to the binding of GA/EGC and LRPs. The phenolic binding led to significant changes in the structure and MW of LRPs. Moreover, antioxidant activity and the macrophage-stimulating effect of LRPs were improved after binding with GA/EGC, depending on the binding amount and type of polyphenol. Interestingly, LRP-GA/EGC complexes with polyphenol binding amounts of 105.4 mg/g and 50.71 mg/g, respectively, showed better stimulation effects on the anti-inflammatory cytokine IL10 secretion of macrophages when compared to LRPs. These results show the great potential of phenolic binding to be applied to improve the structure and functional activity of LRPs.

Recent insights in the impact of emerging technologies on lactic acid bacteria: A review.

Lactic acid bacteria (LAB) have a long history of applications in the food industry for fermentation and preservation. This feature is due to their metabolic products that can improve the nutritional and sensory characteristics of foods as well as their antimicrobial compounds that contribute to extend the shelf life of food products. Some emerging technologies including pulsed electric fields (PEF), power ultrasound (US), high-pressure processing (HPP), ultraviolet (UV), and microwave (MW) have attracted great attention for their implementation in the food industry as mild processing technologies. They have the advantage of efficiently inactivating the microorganisms, along with maintaining the fresh attributes of the food products. When applied at a sub-lethal level, these technologies present the potential to enhance several processes, such as improved microbial growth and fermentation conditions, as well as modified metabolic properties of LAB. This review covers the characteristics of LAB and their applications in the food industry. It discusses the impacts of emerging technologies on these microorganisms, with a special focus on microbial inactivation, growth stimulation, and improvement of the beneficial features of LAB by emerging technologies.

Effect of Pulsed Electric Fields on the Growth and Acidification Kinetics of Lactobacillus delbrueckii Subsp. bulgaricus.

The aim of this work was to investigate the effect of pulsed electric fields (PEF) on the growth and acidification kinetics of Lactobacillus delbrueckii subsp. bulgaricus CFL1 during fermentation. The PEF treatments were applied during the fermentation process using a recirculation pump and a PEF treatment chamber coupled with a PEF generator. The medium flow rate through the chamber was first optimized to obtain the same growth and acidification kinetics than the control fermentation without medium recirculation. Different PEF intensities (60-428 V cm-1) were then applied to the culture medium to study the impact of PEF on the cells' behavior. The growth and acidification kinetics were recorded during the fermentation and the specific growth rates µ, pH, and acidification rate (dpH/dt) were assessed. The results obtained showed a biphasic growth by applying high PEF intensities (beyond 285 V cm-1) with the presence of two maximal specific growth rates and a decrease in the acidification activities. It was demonstrated that the cells were stressed during the PEF treatment, but presented an accelerated growth after stopping it, leading thereby to similar absorbance and pH at the end of the fermentation. These results show the great potential of PEF technology to be applied to generate low acidified products by performing PEF-assisted fermentations.