Diversity Of Fungal Microflora Of Acidic-gruel In Western Inner Mongoliaand Evaluation Of The Effect Of Isolated Strains On Quality

In this paper,Illumina MiSeq high-throughput sequencing technology was used to analyze the fungal diversity of traditional fermented cereal products in 16 samples acidic-gruel in western Inner Mongolia,and the traditional microbial and molecular biological methods were used to isolate and identify the yeast in acidic-gruel.Then,the isolated and advantageous lactic acid bacteria and yeast were separately used to carry out single and compound fennentation of the acidic-gruel products,and the physical and chemical indicators were determined.At the same time,electronic tongue,electronic nose and gas chromatography-mass spectrometry(GC-MS)techniques were used to evaluate the taste and odor quality of the acidic-gruel products.The research results are as follows:(1)A total of 129,760 effective sequences and 10,895 OUT were obtained from 16 acidic-gruel samples,which were obtained by bioinformatics analysis and identified as 6 phyla,15 families,30 orders,52 families and 85 genera.The dominant phylum is Ascomycota,the average relative abundance is 97.54%,and the dominant genus are Candida and Galactomyces,with an average relative abundance are 57.95%and 34.95%,respectively.The dominant OTU were OTU6112 and OTU3445,and both were identified as Candida,with an average relative abundance are 38.56%and 33.70%,respectively.Through weighted UniFrac cluster analysis,it was found that all the samples were clustered into three categories,and the species richness and diversity of the fungal communities between Type Ⅰ and Type Ⅱ samples were due to the relative abundance to Galactomvces and Candida.(2)A total of 50 strains of yeast isolated from 16 acidic-gruel samples were isolated and identified by traditional microbiological methods and molecular biology methods,including 19 strains of Pichia and 11 strains of Geotrichum.There are 6 strains of Kazachstania,7 strains of Candida,2 strains of Saccharomyces,3 strains of Cryptococcus,and I strain of Zygoascus hellenicus and Saturnispora silvae.It is further known that the dominant yeast in acidic-gruel is Pichia kudriavzevii,a total of 14 strains.(3)There was no significant difference in the taste quality between the single fermented acidic-gruel of lactic acid bacteria and the fermented acidic-gruel with Pichia kudriavzevii(P>0.05),but there was a significant difference between the yeast single fermented acidic-gruel and the other two groups of acidic-gruel(P<0.001),the difference between the taste is bitter and salty,it can be seen that Pichia kudriavzevii has no positive effect on the taste quality of acidic-gruel.There was a significant difference in the flavor quality between the yeast group and the other two groups of acidic-gruel(P<0.001).It was found by GC-MS that 3-methyl-1-butanol,hexanal,ethyl acetate and ethanol were the main volatile flavor substances which caused the difference,and it was found that Pichia kudriavzevii had no positive influence on the flavor quality of the acidic-gruel.