Mechanism of exogenous methyl jasmonate in regulating the quality of fresh-cut Chinese water chestnuts.

Fresh-cut Chinese water chestnuts (CWCs) are susceptible to yellowing and browning during storage due to mechanical damage and the loss of protective outer skin, adversely affecting their marketability and shelf life. Methyl jasmonate (MeJA) is currently extensively used for food preservation, but it has not been used in Chinese water chestnuts. This study investigated the effect of MeJA treatment on the quality of fresh-cut CWCs. Fresh-cut CWCs immersed in 20 µM MeJA solution for 10 min and stored at 10°C for 5 d effectively delayed the yellowing process, reduced the respiration rate, and minimized the weight and soluble solids loss during storage. In addition, MeJA treatment induced the activities of superoxide dismutase (SOD) and catalase (CAT), which improved the antioxidant capacity of fresh-cut CWCs and inhibited the generation of reactive oxygen species (ROS). Meanwhile, MeJA treatment inhibited the activities of phenylalanine aminotransferase (PAL), polyphenol oxidase (PPO) and peroxidase (POD). The results of quantitative real-time PCR (qRT-PCR) showed that MeJA down-regulated the expression of CwCHS1, CwCHS2, CwCHS3 and CwCHI2 in freshly cut CWCs and inhibited the accumulation of flavonoids, thus delaying the surface discoloration of freshly cut CWCs.

A Benzothidiazole-Based Reversible Fluorescent Probe with Excellent Performances in Selectively and Sensitively Sensing of Hg2+ in Water.

The development of mercury ion selective fluorescent probe is significant because it is one of toxic heavy metals and poses great risks and hazards to human health. Herein, we develop a mercury ion-selective fluorescent probe, namely IB, based on imidazole decorated benzothiadiazole that obtained by a facile palladium catalytic C-N coupling reaction. IB exhibits high selectivity and sensitivity towards mercury ion in water with nearly 32-fold fluorescent enhancement. The detection limit is calculated to be 0.93 nmol/L. In addition, the sensing of mercury ion can be conducted in a wide pH scope ranging from 4.0 to 10.0. Subsequently, the mercury ion elicits fluorescence of IB solution can be quenched by the addition of cyanide anions, showing "off-on-off" fluorescence transformation with at least 5 cycles, demonstrating the reversible sensing ability of IB. Furthermore, an INHIBIT logical detector has been developed using mercury ion and cyanide anions as inputs and fluorescence of IB as output. Significantly, IB can be utilized for mercury ion detection in real water sample.