Nanoemulsion containing Yellow Monascus pigment : Fabrication, characterization, storage stability, and lipase hydrolytic activity in vitro digestion.

The natural pigment of monascus is favored by human for its special coloring and physiological activity, and its development and application have attracted much attention. In this study, a novel corn oil-based nanoemulsion encapsulated with Yellow Monascus Pigment crude extract (CO-YMPN) was successfully prepared via the phase inversion composition method. The fabrication and stable conditions of the CO-YMPN including Yellow Monascus pigment crude extract (YMPCE) concentration, emulsifier ratio, pH, temperature, ionic strength, monochromatic light and storage time were investigated systemically. The optimized fabrication conditions were the emulsifier ratio (5:3 ratio of Tween 60 to Tween 80) and the YMPCE concentration (20.00% wt%)). Additionally, the DPPH radical scavenging capability of the CO-YMPN (19.47 ± 0.52%) was more excellent than each YMPCE or corn oil. Moreover, the kinetic analysis results based on Michaelis-Menten equation and constant revealed that CO-YMPN could improve lipase hydrolysis capacity. Therefore, the CO-YMPN complex had excellent storage stability and water solubility in the final water system, and the YMPCE showed brilliant stability.

Regulating polymerization degree of heptazines in carbon nitride with fumaric acid to enhance photocatalytic activity.

Carbon nitride (CN) has a wide range of applications in photocatalytic treatment of environmental pollution. One of key challenges in the field is to conveniently prepare CN with tunable band gap towards efficient pollution degradation, which can be overcome by regulating the polymerization degree of its heptazines. Herein, a facile and green strategy to construct CN through co-firing urea, melamine and fumaric acid was reported. By simply inducing appropriate amount of fumaric acid during amidation reaction between fumaric acid and amino groups, the distance between heptazines of CN could be modified to obtain optimized polymerization degree and morphology. Among the considered CN systems, the modulated CN sample with the doped ratio of 2.50: 0.50: 0.03 m urea/m melamine/m fumaric acid (CNF30) displayed remarkable photocatalytic ability due to the largest specific surface area, the lowest photoluminescence emission intensity, and narrowest band gap, which led to the highest 98.0% methyl orange degradation within 60 min under a 10 W lamp and room temperature with the harmless and valuable carboxylic acids products. This study provides a new sight for the design of photocatalysts with tunable band structure towards green and efficient photocatalytic degradation of environmental pollution.

A highly sensitive octopus-like azobenzene fluorescent probe for determination of abamectin B1 in apples.

The development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5'-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule has been characterized by ultraviolet-visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectra. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L-1 and 4.4 µg L-1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was present based on relative standard deviation of 2.2%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe demonstrated reasonable sensitivity, specificity and selectivity. The results indicate that the octopus-like azobenzene fluorescent probe can be expected to be reliable for evaluating abamectin B1 in agricultural foods.