陇西腊肉传统制作过程中细菌群落演替对脂肪水解及氧化的影响

Effect of Bacterial Community Succession on Lipid Hydrolysis and Oxidation during the Traditional Processing of Longxi Bacon,a Traditional Chinese Fermented Meat Product

为探究陇西腊肉传统制作过程中细菌群落演替对脂肪水解及氧化的影响,采用Illumina MiSeq测序技术解析陇西腊肉制作过程中微生物群落结构及演替规律,并结合气相色谱-质谱联用技术检测制作过程中脂肪酸组成及含量变化,以及肉样中酸价、过氧化值的变化。结果表明:测序深度有效地覆盖了样品中绝大部分细菌种类,测序结果进行整理、过滤后共得到186866条有效序列,聚类后有580个可操作分类单元,注释到15个门,414个属。整个制作过程中,Proteobacteria和Firmicutes为优势细菌门,而Brochothrix、Carnobacterium、Lactobacillus、Pseudoalteromonas、Psychrobacter和Cupriavidus为优势细菌属。通过PICRUSt软件分析,菌群中与脂肪酸代谢相关基因的丰度较高;脂肪酸组成分析揭示棕榈酸(C_(16:0))、硬脂酸(C_(18:0))、棕榈油酸(C_(16:1))、油酸(C_(18:1))、亚油酸(C_(18:2n6c))是主要的成分,占比达到83.84%~92.43%。通过相关分析得到:Streptococcus、Staphylococcus、Lactobacillus、Cupriavidus、Carnobacterium、Brochothrix是陇西腊肉制作过程中参与脂肪代谢的相关菌群,其中,Streptococcus、Lactobacillus与饱和脂肪酸、多不饱和脂肪酸变化相关;而Carnobacterium、Staphylococcus、Brochothrix、Cupriavidus主要参与不饱和脂肪酸代谢,并与棕榈油酸、油酸、亚油酸含量的变化密切相关。

In order to investigate the effect of bacterial community succession on lipid metabolism during the traditional production of Longxi bacon,Illumina MiSeq sequencing was used to analyze the bacterial community structure and succession at the genome level,and gas chromatography-mass spectrometry(GC-MS)was used to detect changes in fatty acid composition and contents during the production process.Additionally,changes in acid value(AV)and peroxide value(POV)were determined.The results showed that the sequencing depth covered most bacterial species in the samples.After sorting out and filtering the sequencing results,186866 effective sequences were obtained.After clustering,580 operational taxonomic units(OTUs)were annotated to 414 genera in 15 phyla.During the whole production process,Proteobacteria and Firmicutes were the dominant bacterial phyla.Brochothrix,Carnobacterium,Latobacillus,Pseudoalteromonas,Psychrobacter and Cupriavidus were the dominant genera.Through function prediction with PICRUSt software,it was found that the abundance of the genes related to fatty acid metabolism was relatively high in the microflora.Fatty acid composition analysis revealed that palmitic acid(C_(16:0)),stearic acid(C_(18:0)),palmitic acid(C_(16:1)),oleic acid(C_(18:1)),and linoleic acid(C_(18:2n6c))were the major components,accounting for 83.84%–92.43%of the total fatty acids.According to correlation analysis,it was found that the bacteria related to lipid metabolism during the production of Longxi bacon mainly included Streptococcus,Staphylococcus,Lactobacillus,Cupriavidus,Carnobacterium and Brochothrix.Streptococcus and Lactobacillus were related to changes in saturated fatty acids and polyunsaturated fatty acids,while Carnobacterium,Staphylococcus,Brochothrix and Cupriavidus were mainly involved in the metabolism of unsaturated fatty acids,closely related to changes in palmitoleic acid,oleic acid and linoleic acid.