Defective UiO-66/cellulose nanocomposite aerogel for the adsorption of heterocyclic aromatic amines.

Heterocyclic aromatic amines (HAAs), arising as chemical derivatives during the high-temperature culinary treatment of proteinaceous comestibles, exhibit notable carcinogenic potential. In this paper, a composite aerogel (AGD-UiO-66) with high-capacity and fast adsorption of HAAs was made with anchoring defective UiO-66 (D-UiO-66) mediated by lauric acid on the backbone of cellulose nanofibers (CNF). AGD-UiO-66 with hierarchical porosity reduced the mass transfer efficiency for the adsorption of HAAs and achieved high adsorption amount (0.84-1.05 µmol/g) and fast adsorption (15 min). The isothermal adsorption model demonstrated that AGD-UiO-66 belonged to a multilayer adsorption mechanism for HAAs. Furthermore, AGD-UiO-66 was successfully used to adsorb 12 HAAs in different food (roasted beef, roasted pork, roasted salmon and marinade) with high recoveries of 94.65%-104.43%. The intrinsic potential of AGD-UiO-66 demonstrated that it could be widely applicable to the adsorption of HAAs in foods.

In-situ growth of metal-organic frameworks on cellulose nanofiber aerogels for rapid adsorption of heterocyclic aromatic amines.

Heterocyclic aromatic amines (HAAs) are the main carcinogens produced during thermal processing of protein-rich foods. In this paper, a composite aerogel (TOCNFCa) with a stabilized dual-network structure was prepared via a template for the in-situ synthesis of UiO-66 on cellulose for the adsorption of HAAs in food. The dual-network structure of TOCNFCa provides the composite aerogel with excellent wet strength, maintaining excellent compressive properties. With the in-situ grown UiO-66 content up to 71.89 wt%, the hierarchical porosity endowed TOCNFCa@UiO-66 with the ability to rapidly adsorb HAAs molecules with high capacity (1.44-5.82 µmol/g). Based on excellent thermal stability, adsorption capacity and anti-interference, TOCNFCa@UiO-66 achieved satisfactory recoveries of HAAs in the boiled marinade, which is faster and more economical than the conventional SPE method. Moreover, TOCNFCa@UiO-66 could maintain 84.55 % of the initial adsorption capacity after 5 times of reuse.

Antibacterial Activity and Potential Application in Food Packaging of Peptides Derived from Turbot Viscera Hydrolysate.

As a good choice for food preservation, antimicrobial peptides (AMPs) have received much attention in recent years. In this paper, peptides derived from the turbot viscera hydrolysate were identified by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS), and the physicochemical properties and structural characteristics were analyzed by in silico tools. Furthermore, three cationic peptides with potential hydrophobicity and amphipathy were synthesized; their cytotoxicity, hemolysis, and antibacterial activities were investigated. In particular, Sm-A1 (GITDLRGMLKRLKKMK), a peptide with 16 amino acids, showed an outstanding antibacterial activity against both Gram-positive and Gram-negative bacteria by damaging the cell membrane integrity. Moreover, Sm-A1 was successfully loaded into hydroxyl-rich poly(vinyl alcohol) (PVA)/chitosan (CS) hydrogel to improve the antibacterial activity and biofilm inhibition effect. PVA/CS+7.5‰ Sm-A1 hydrogel can satisfactorily protect the salmon muscle from the microbiological contamination and texture deterioration.

Lentibacillus panjinensis sp. nov., Isolated from Shrimp Paste, a Traditional Chinese Fermented Seafood.

A Gram-positive, aerobic, motile and short rod-shaped bacterium, designated as strain G56T, was isolated from shrimp paste produced in Panjin, China. Grows in the presence of 1.0-25.0% (w/v) NaCl (optimum at 10%), pH 5.0-9.5 (optimally at 7.0) and 10-50 °C (optimally at 37 °C). Positive for catalase and oxidase activities, but lack the ability to reduce nitrate. Acids produce from D-ribose, D-xylose, D-galactose, glycerol and D-trehalose, but no acid is produced when salicin, D-mannose, D-cellobiose and L-sorbose are provided as substrates. The polar lipid extract is found to contain diphosphatidylglycerol, phosphatidylglycerol, an unknown glycolipid, and unidentified phospholipids. Fatty acids are mainly defined as anteiso-C15:0 (69.7%) and anteiso-C17:0 (23.3%). The G+C content of its DNA is 44.7 mol%. The draft genome of strain G56T is 3,209,087 bp in length and the average nucleotide identity value (ANI) and the digital DNA-DNA hybridization (DDH) values between strain G56T and L. juripiscarius JCM 12147T is 78.41% and 22.0%, respectively. Polyphasic taxonomic analysis classified strain G56T as a novel species in the genus Lentibacillus, and therefore, we named it as Lentibacillus panjinensis sp. nov..

Fluorescent carbon dots in baked lamb: Formation, cytotoxicity and scavenging capability to free radicals.

The formation and properties of nanostructures during food processing have attracted much attention in recent years. Herein, the formation and physicochemical properties of fluorescence carbon dots (CDs) from baked lamb at different baking temperatures (200, 300, and 350 °C) were investigated. The morphology, surface functional groups and fluorescent quantum yield of the CDs were found to be highly dependent on the heating temperature. Biocompatibility of CDs investigation indicated that they were able to disperse onto both the cell membrane and the cytoplasm of HepG2 cells, and alter the cell cycle progression slightly. Moreover, the CDs from baked lamb of 350 °C showed the maximum scavenging capability to free radicals and could protect the cell from oxidative damage in vitro. This contribution represents the first report regarding the properties and formation process of CDs in baked lamb, providing valuable insights into baking temperature influence on physicochemical properties of the CDs.

Multicolorful Carbon Dots for Tumor Theranostics.

BACKGROUND: Cancer is a great threat of human health worldwide due to the uncontrollable spread of malignant cells throughout the body. Accurate diagnosis and targeted therapy approaches are critical factors for cancer treatment. Combination of therapeutic and diagnostic agents in a single nanocarrier enables to simultaneously monitor the cancer progression and tune disease therapy with minimum side effect. OBJECTIVE: Carbon dots are a novel class of small fluorescence carbon nanostructures with size less than 10 nm at least in one dimension, which exhibit excellent optical properties, larger surface area to volume ratio and low toxicity. The unique properties of carbon dots make it as an ideal carrier for incorporation of cancer targeting moieties, bio-imaging agents and antineoplastic agents in one delivery system. METHODS: An literature search was conducted using Web of Science to find out articles related to carbon dots and tumor theranostics. RESULTS: Numerous applications of carbon dots in cancer theranostics have been reported during the past 10 years. This review introduces a brief history and basic fluorescent properties of carbon dots, and then discusses synthesis strategies and applications of carbon dots in biological imaging, targeted anti-cancer drug delivery, photodynamic therapy, photothermal therapy as well as gene delivery for cancer theranostics. Future directions of carbon dots in cancer theranostics are also highlighted.

Nanostructures Derived from Starch and Chitosan for Fluorescence Bio-Imaging.

Fluorescent nanostructures (NSs) derived from polysaccharides have drawn great attention as novel fluorescent probes for potential bio-imaging applications. Herein, we reported a facile alkali-assisted hydrothermal method to fabricate polysaccharide NSs using starch and chitosan as raw materials. Transmission electron microscopy (TEM) demonstrated that the average particle sizes are 14 nm and 75 nm for starch and chitosan NSs, respectively. Fourier transform infrared (FT-IR) spectroscopy analysis showed that there are a large number of hydroxyl or amino groups on the surface of these polysaccharide-based NSs. Strong fluorescence with an excitation-dependent emission behaviour was observed under ultraviolet excitation. Interestingly, the photostability of the NSs was found to be superior to fluorescein and rhodamine B. The quantum yield of starch NSs could reach 11.12% under the excitation of 360 nm. The oxidative metal ions including Cu(II), Hg(II)and Fe(III) exhibited a quench effect on the fluorescence intensity of the prepared NSs. Both of the two kinds of the multicoloured NSs showed a maximum fluorescence intensity at pH 7, while the fluorescence intensity decreased dramatically when they were put in an either acidic or basic environment (at pH 3 or 11). The cytotoxicity study of starch NSs showed that low cell cytotoxicity and 80% viability was found after 24 h incubation, when their concentration was less than 10 mg/mL. The study also showed the possibility of using the multicoloured starch NSs for mouse melanoma cells and guppy fish imaging.