土霉素残留对蔬菜发酵过程微生物群落演替及代谢产物的影响

【目的】探究土霉素残留对蔬菜自然发酵过程中微生物群落演替和代谢产物动力学的影响,为评估抗生素残留对蔬菜发酵的影响提供理论基础。【方法】超高效液相色谱-串联质谱法测定土霉素残留;高效液相色谱法测定有机酸、电子鼻和气相色谱-质谱联用测定挥发性成分和高通量技术测定微生物种类。【结果】蔬菜自然发酵过程中,土霉素残留从4.00 mg/L下降到2.53 mg/L;不含抗生素残留的蔬菜发酵含有同型和异型乳酸发酵,而土霉素残留的蔬菜发酵仅含有同型乳酸发酵;同时,其特征微生物由Lactobacillus pentosus和Lactobacillus plantarum转变为Lactobacillus paratarrginis、Lactobacillus buchneri和Lactobacillus kisonensis;土霉素残留明显影响了乳酸、柠檬酸、乙酸、香茅醇、3-辛醇、异硫氰酸烯丙酯、乙酸香叶酯、乙烯基硬脂醚和异硫氰酸苯乙酯等代谢产物的含量。【结论】土霉素残留影响了蔬菜乳酸发酵的类型、微生物群落的演替、有机酸和挥发性化合物的形成过程,因此应将抗生素残留纳入发酵蔬菜原料的质量控制指标。

Oxytetracycline residue alters profiles of microbial communities and metabolites during vegetable fermentation

Objective] To study the changes in microbial communities and metabolites during the vegetable fermentation exposed to oxytetracycline residue and further provide a theoretical basis for evaluating the effects of antibiotic residue on vegetable fermentation. Methods] In this study, we determined the oxytetracycline residue by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), organic acids by high performance liquid chromatography (HPLC), volatile components by the electronic nose and gas chromatography mass spectrometry (GC-MS), microbial species by high-throughput sequencing. Results] The oxytetracycline residue decreased from 4.00 mg/L to 2.53 mg/L in spontaneous vegetable fermentation. The vegetable without oxytetracycline residue experienced homolatic and heterolactic fermentation, while that with oxytetracycline residue only experienced homolatic fermentation. Meantime, the characteristic microorganisms changed from Lab. pentosus and Lab. plantarum to L. paratarrginis, Lab. buchneri, and Lab.kisonensis. Furthermore, oxytetracycline residue significantly affected the content of lactic acid, citric acid, acetic acid, citronellol, 3-octanol, allylsenevol, geranyl acetate, and phenylethyl isothiocyanate. Conclusion] Oxytetracycline residue affected the type of vegetable lactic acid fermentation, the succession of microbial communities, and the production of organic acids and volatile compounds. Therefore, the antibiotic residue should be listed as a quality control indicator of raw vegetable materials for fermentation.