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Abstract β-lactoglobulin (β-lg), the predominant protein in bovine whey, was chemically modified by (−)-epigallocatechin-3-gallate (EGCG) to develop a biomacromolecule with antioxidant activity. The EGCG-modified β-lg was characterized by SDS-PAGE, MALDI-TOF MS and intrinsic fluorescence spectroscopy. The antioxidant properties of EGCG-modified β-lg was assessed using DPPH radical scavenging activity, iron chelating ability, and inhibition of Cu2+-induced LDL oxidation. SDS-PAGE and MALDI-TOF MS results indicated the dimerization of β-lg after EGCG modification. Intrinsic fluorescence spectra suggested that EGCG modification caused an alteration in the conformational structure of β-lg. The results demonstrated that EGCG-modified β-lg possessed great antioxidant potential in terms of scavenging DPPH radical and chelating ferrous ion. Furthermore, the EGCG-modified β-lg showed a protective effect against LDL peroxidation. The results indicate that EGCG-modified β-lg could provide significant health benefits as an antioxidant. Highlights • Covalent modification by EGCG caused the formation of β-lg dimer. • EGCG modification altered β-lg conformation making it more hydrophilic. • EGCG-modified β-lg is a novel biomacromolecule with antioxidant activity. [ABSTRACT FROM AUTHOR]

A simple, sensitive, accurate and affordable rapid detection of meat species authentication is urgently needed in food industry. In this study, a cross priming amplification (CPA) combining nucleic acid test strip (CPA-Strip) assay for rapid detection of mutton from meat mixture were developed and its feasibility was investigated. In an isothermal CPA system, cytochrome b ( cytb ) gene as target was amplified at 63 °C for 60 min. The nucleic acid strip was able to show the corresponding test line in the presence of target gens in 5 min. Non-targeting gene interference was not evident. The CPA-Strip has been applied for the detection of 0.1–100% mutton in a thermal treated meat mixtures with a detection limit of a detect limit of 1%. CPA-Strip assay would be a promising simple, rapid and sensitive method for identification of target species in raw and processed meat mixtures. [ABSTRACT FROM AUTHOR]

Abstract: Novel BOPIM (boron 2-(2′-pyridyl)imidazole complex) derivatives with large Stokes shift were efficiently synthesized through two-step reactions, starting from commercially available 2-pyridinecarboxaldehyde and α-diketone. The dyes exhibit high fluorescent intensity in solution and also in solid state due to the intermolecular non-planar interactions. According to X-ray single crystal measurements, the non-covalent interactions (such as C–H⋯F–B, etc.) play important role in inhibiting planar π–π stacking, and the existence of terminal phenyl rings increases the electronic density of π system, which facilitates the charge transfer from the electron-donating π system to the electron-accepting boron moiety. DFT calculation based on X-ray crystallographic analysis was carried out for compound 2, giving consistent results with photophysical measurements. [Copyright &y& Elsevier]

Nitrogen dynamics and budgets in a clay loam soil (Meadow Aqualf) in the North China Plain were investigated in a winter wheat (Triticum aestivum L.) and maize (Zea mays L.) cropping system comparing the effects of four N rates (0, 120, 240 and 360 kg N ha−1 as urea) applied twice to each crop over 2 years. Ammonium nitrogen (NH4-N) in the soil profile remained at a low and constant level (except in the surface 20 cm layer) following application of fertilizer N. In contrast, nitrate nitrogen (NO3-N) levels were significantly altered by the rate of applied N. A strong tendency of NO3-N to move from the surface layer to the lower layers (20–100 cm) was observed during the wheat and maize growth seasons in treatments of 240 and 360 kg N ha−1 per crop (N240 and N360). The amounts of NO3-N accumulated in the soil profile were significantly higher in N240 and N360 than those in N0 and N120 (treatments receiving 0 and 120 kg N ha−1 per crop). After 2 years, soil NO3-N levels at 0–300 cm depth in N120, N240 and N360 amounted to 336, 815 and 1141 kg ha−1, respectively, with more than half of these amounts distributed in the 100–300 cm layer. The calculated total N balance indicates that most fertilizer N was available as NO3-N in the top 300 cm of the soil profile using traditional fertilization and irrigation practices. Over the subsequent 2 years, N losses were calculated to be relatively low in N120 but significantly higher in N240 and N360. Measured gaseous N losses showed that NH3 volatilization and denitrification comprised only a small fraction of total N losses during the 2-year rotation, while NO3-N leaching from the top 100 cm of the soil profile accounted for most N losses across all N rates and experimental years. The N budget showed that accumulation and/or leaching of NO3-N below 100 cm depth (beyond the reach of most roots) was the main pathway for N losses in the winter wheat–maize cropping system. The recommended N application rate of 120 kg N ha−1 minimized soil NO3-N accumulation and leaching losses while maintaining high yields and N utilization by winter wheat and maize. [Copyright &y& Elsevier]