The enantioselective effects and potential risks of paclobutrazol residue during cucumber pickling process

Abstract

For decades, pesticides have been widely used for controlling pests and protecting crops around the world, and the food safety issues caused by these compounds have raised widespread concern. However, the different enantioselective behaviors and biological activities of chiral pesticide enantiomers are often ignored. In this work, a novel method was put forward to investigate the enantioselective effects and potential risks of two paclobutrazol enantiomers during cucumber pickling process. The degradation kinetics indicated that when paclobutrazol reside in cucumber and was introduced into the pickling process, the half-time of paclobutrazol isomers were significantly different (9.24 d and 16.6 d), and the conversion phenomenon between the two enantiomers could also be observed. In addition, results from 16S rRNA and ITS sequencing shown that (2R, 3R)-paclobutrazol and (2S, 3S)-paclobutrazol have an obviously enantiomeric effects on microbial community of pickling system and the degradation of paclobutrazol was probably attributed to the presence of Pseudomonas and Serratia. Finally, the microorganisms functions were found to be disrupted under the exposure of (2R, 3R)-paclobutrazol and metabolic function of microorganisms to xenobiotic was inhibited, which might cause potential risks to the quality of preserved foods. In summary, we have devised a method and provided a novel insight into the potential risks of chiral pesticide residues on food safety and human health.

Keywords: Enantiomeric effect; High-throughput sequencing; Microorganism; Paclobutrazol; Stereoselectivity.