壳寡糖对泡菜品质、微生物多样及演替规律的影响

Effects of Chitosan Oligosaccharides on the Quality and Microbial Diversity of Pickles

研究壳寡糖对泡菜品质、微生物多样及演替规律的影响,探究其在泡菜生产中的应用潜力。研究表明:壳寡糖能有效降低泡菜中亚硝酸盐含量,提高泡菜中总酸、氨基酸态氮含量,且随壳寡糖含量的增加呈现明显差异。当壳寡糖添加量为1%(质量分数)时,试验组的亚硝酸盐含量为(1.08±0.39)mg/kg(减少近50%)、总酸为(7.42±0.25)g/kg(提高87%)和氨基酸态氮为(56.67±7.5)g/kg(增加32%)。分析发现,壳寡糖显著影响泡菜发酵过程中微生物区系结构。壳寡糖泡菜样品与自然发酵样品中的优势微生物在门水平分析相类似,均为变形菌门和厚壁菌门,而在属水平出现较大差异,如自然发酵组共有17种属微生物参与泡菜的发酵过程,而壳寡糖泡菜仅9种属微生物。发酵中期(3 d),添加壳寡糖使得自然发酵过程中的优势菌微小杆菌属被乳球菌属所取代;发酵5 d后,自然发酵样品中泛菌属和明串球菌属共同主导着发酵的进程,而壳寡糖泡菜中优势菌属仍是乳球菌属,并延续至发酵末期。结论:添加壳寡糖有利于泡菜发酵过程中有益菌群的增长及泡菜品质的提升,壳寡糖在泡菜生产中的应用潜力大。

In this study, we utilize the high-throughput sequencing to profile while analyzing the bacterial communities and the quality of pickles with chitosan oligosaccharides. The results have indicated that chitosan oligosaccharides can effectively reduce the nitrite content, increased the total acid and amino acid nitrogen content in pickles. When the chitosan percentage in pickles was 1%, the nitrite content of the test group was(1.08±0.39) mg/kg(50%), the total acid was(7.42±0.25) g/kg(187%) and the amino acid nitrogen was(56.67±7.5) g/kg(132%). The microbial community structure was obviously affected by chitosan oligosaccharides. Further analysis indicated that Firmicutes and Proteobacteria were the dominant phyla in the samples during the fermentation. Among them, a total of 17 species of microorganisms were observed as the genus during the natural fermentation group. However, only 9 species of microorganisms were observed in chitosan pickles. At the middle stage of fermentation(3 d), the addition of chitooligosaccharide caused the dominant bacteria Exiguobacterium to be replaced by Lactococcus in the natural fermentation process. After 5 days of fermentation,Pantoea and Leuconostoc dominate the fermentation process in the naturally fermented samples, while the dominant genus in chitosan pickles is Lactococcus and continues to the end of the fermentation process. In summary, the results showed that chitosan oligosaccharide(COS) is expected to improve the growth of beneficial bacteria and the quality of pickles during the fermentation process.