Autoclaving-treated germinated brown rice relieves hyperlipidemia by modulating gut microbiota in humans.

Introduction: Germinated brown rice is a functional food with a promising potential for alleviating metabolic diseases. This study aimed to explore the hypolipidemic effects of autoclaving-treated germinated brown rice (AGBR) and the underlying mechanisms involving gut microbiota. Methods: Dietary intervention with AGBR or polished rice (PR) was implemented in patients with hyperlipidemia for 3 months, and blood lipids were analyzed. Nutritional characteristics of AGBR and PR were measured and compared. Additionally, 16S rDNA sequencing was performed to reveal the differences in gut microbiota between the AGBR and PR groups. Results: AGBR relieves hyperlipidemia in patients, as evidenced by reduced levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein-B, and elevated levels of high-density lipoprotein cholesterol and apolipoprotein-A1. In terms of nutrition, AGBR had significantly higher concentrations of free amino acids (10/16 species), γ-aminobutyric acid, resistant starch, soluble dietary fiber, and flavonoids (11/13 species) than PR. In addition, higher microbial abundance, diversity, and uniformity were observed in the AGBR group than in the PR group. At the phylum level, AGBR reduced Firmicutes, Proteobacteria, Desulfobacterota, and Synergistota, and elevated Bacteroidota and Verrucomicrobiota. At the genus level, AGBR elevated Bacteroides, Faecalibacterium, Dialister, Prevotella, and Bifidobacterium, and reduced Escherichia-Shigella, Blautia, Romboutsia, and Turicibacter. Discussion: AGBR contributes to the remission of hyperlipidemia by modulating the gut microbiota.

Ultrasound driven conformational and physicochemical changes of soy protein hydrolysates.

The effect of ultrasound on the conformational and physicochemical properties of soy protein isolate hydrolysates (SPHs) was investigated. SPHs were prepared at hydrolysis times of 20 min, 60 min, and 180 min, then treated with ultrasound for 10 min, 20 min, and 30 min at a frequency of 20 kHz and output powers of 150 W and 450 W. The structural properties and antioxidant capacities of the aqueous layer of SPHs (ASPHs) after sonication were evaluated by Fourier-transform infrared spectroscopy (FTIR), intrinsic fluorescence, DPPH radical scavenging activity assays, and microscopy observations. Results obtained showed that ultrasound treatment significantly disrupted the peptide aggregates formed during protein hydrolysis. The protein solubility was significantly increased after sonication (by up to 18.33%), as did the percentage of proteins with MW < 1 kDa in ASPHs. The antioxidant capacity of ASPHs also increased, as measured by DPPH assay. FTIR analysis of ASPHs indicated that the protein secondary structures were different, with an increase in ß-sheet and a decrease in α-helix and ß-turn. Furthermore, the changes in fluorescence spectra of ASPHs showed the transition of protein tertiary structure with a greater exposure of Trp residues in the side chains. Scanning electron microscope (SEM) and atomic force microscope (AFM) observations of the morphological structure of ASPHs further confirmed the significant effect of sonication on disrupting peptide aggregates. In conclusion, ultrasound can be used as an efficient treatment to promote the solubility of protein hydrolysates.

Au-Ag and Pt-Ag bimetallic nanoparticles@halloysite nanotubes: morphological modulation, improvement of thermal stability and catalytic performance.

In this study, Au-Ag and Pt-Ag bimetallic nanocages were loaded on natural halloysite nanotubes (HNTs) via galvanic exchange based on Ag@HNT. By changing the ratio of Au to Ag or Pt to Ag in exchange processes, Au-Ag@HNT and Pt-Ag@HNT with different nanostructures were generated. Both Au-Ag@HNT and Pt-Ag@HNT systems showed significantly improved efficiency as peroxidase-like catalysts in the oxidation of o-phenylenediamine compared with monometallic Au@HNT and Pt@HNT, although inert Ag is dominant in the composition of both Au-Ag and Pt-Ag nanocages. On the other hand, loading on HNTs enhanced the thermal stability for every system, whether monometallic Ag nanoparticles, bimetallic Au-Ag or Pt-Ag nanocages. Ag@HNT sustained thermal treatment at 400 °C in nitrogen with improved catalytic performance, while Au-Ag@HNT and Pt-Ag@HNT maintained or even had slightly enhanced catalytic efficiency after thermal treatment at 200 °C in nitrogen. This study demonstrated that natural halloysite nanotubes are a good support for various metallic nanoparticles, improving their catalytic efficiency and thermal stability.

Characterizations of the Formation of Polydopamine-Coated Halloysite Nanotubes in Various pH Environments.

Recent studies demonstrated that polydopamine (PDA) coating is universal to nearly all substrates, and it endows substrates with biocompatibility, postfunctionality, and other useful properties. Surface chemistry of PDA coating is important for its postmodifications and applications. However, there is less understanding of the formation mechanism and surface functional groups of PDA layers generated in different conditions. Halloysite is a kind of clay mineral with tubular nanostructure. Water-swellable halloysite has unique reactivity. In this study, we have investigated the reaction of dopamine in the presence of water-swellable halloysite. We have tracked the reaction progresses in different pH environments by using UV-vis spectroscopy and surface-enhanced Raman spectroscopy (SERS). The surface properties of PDA on halloysite were clarified by X-ray photoelectron spectroscopy (XPS), SERS, Fourier transform infrared (FTIR) characterizations, zeta potential, surface wettability, and morphological characterizations. We noticed that the interaction between halloysite surface and dopamine strongly influences the surface functionality of coated PDA. In addition, pH condition further modulates surface functional groups, resulting in less content of secondary/aromatic amine in PDA generated in weak acidic environment. This study demonstrates that the formation mechanism of polydopamine becomes complex in the presence of inorganic nanomaterials. Substrate property and reaction condition dominate the functionality of obtained PDA together.