聚赖氨酸和1-MCP联合处理对草菇贮藏期间表面细菌变化的影响

Effect of ε-polylysine combined with 1-MCP on the surface bacteria of Volvariella volvacea fruit bodies during storage

摘要:

【背景】草菇具有很高的营养价值和药用价值，草菇采后品质易劣变主要是由其表面腐败菌引起的。保鲜处理条件下草菇表面菌的研究目前未见相关报道。【目的】探究聚赖氨酸(ε-polylysine，ε-PL)和1-甲基环丙烯(1-methylcyclopropene，1-MCP)联合处理对草菇贮藏期间表面细菌变化的影响。【方法】采用平板培养与16S rRNA基因高通量测序技术两种方法，分离、鉴定ε-PL和1-MCP联合处理后草菇贮藏期间的表面微生物，确定草菇贮藏期间菇体表面优势腐败菌。【结果】平板培养法结果表明，草菇子实体表面的菌落总数随着贮藏时间的延长逐渐上升。贮藏6 d时，处理组(PC)草菇表面菌落总数为7.16 lg (CFU/g)，极显著(P<0.01)低于CK组[7.42 lg (CFU/g)]；从PC组、CK组分离鉴定的细菌分别为16株和19株，以假单胞菌属、金黄杆菌属、芽孢杆菌属和寡养单胞菌属为主；16S rRNA基因高通量测序结果表明，PC组共鉴定出370个属的细菌隶属于27个门；CK组共鉴定出366个属的细菌隶属于25个门；寡养单胞菌属为相对丰度最高的优势菌。【结论】寡养单胞菌属为草菇优势腐败菌之一，ε-PL联合1-MCP处理可明显抑制草菇贮藏期间表面细菌的生长。

Abstract:

[Background] Volvariella volvacea has high nutritional and medicinal value. Post-harvest quality deterioration of V. volvacea fruit bodies (VVFB) is mainly caused by the surface spoilage bacteria. There is no report on the surface bacteria of VVFB under fresh-keeping treatment. [Objective] To investigate the effect of ε-polylysine (ε-PL) combined with 1-methylcyclopropene (1-MCP) on surface bacteria of VVFB during storage. [Methods] VVFB were treated with ε-PL and 1-MCP and then stored. Through the plate culture method and 16S rRNA gene high-throughput sequencing, the surface bacteria of VVFB during storage were isolated and identified, and the dominant spoilage bacteria were determined. [Results] The plate culture method showed that the total number of colonies on the surface of VVFB increased during the storage. To be specific, the colony number of the treatment group (PC, ε-PL+1-MCP) was up to 7.16 lg (CFU/g) on the 6th day, smaller (P<0.01) than that 7.42 lg (CFU/g) in the control group (CK). A total of 16 and 19 strains were isolated from the PC group and CK group, respectively, which were dominated by Pseudomonas, Chryseobacterium, Bacillus, and Stenotrophomonas. The 16S rRNA gene high-throughput sequencing suggested 370 bacterial generas in 27 phylas were identified in the PC group, and 366 generas in 25 phylas were identified in the CK group. Among the strains, Stenotrophomonas had the highest relative abundance. [Conclusion] Stenotrophomonas is one of dominant spoilage bacterial genus of VVFB, and ε-PL combined with 1-MCP can effectively inhibit the growth of bacteria on the surface of VVFB.