| Chinese traditional broad bean paste with chili(CBBPC)is fermented through traditional natural spontaneous fermentation technology,which consist of Tianbanzi,chili pei,mixture fermentation three different fermentated stages.The complex microorganism community completes the degradation of protein,carbohydrate,fat and other substances and produces the unique taste of CBBPC.However,the knowledge of the the succession of bacterial community and the composition of flavor compounds in every fermentation stage is also not very clear,especially the correspondence between microbial community and flavor compounds,which hindered the development of broad bean paste with chili industry greatly.In this paper,changes of physical and chemical indexes,flavor compounds and the dynamic changes of bacterial community were analyzed during the whole fermerntation process of broad bean paste with chili.Not noly the correspondence between fermentation conditions and bacterial compositions and but also the correspondence between bacteria and flavor substances were analyzed by canonical correspondence analysis(CCA)to reveal the regular pattern of the knowledge of broad bean paste with chili fermentation theory.Firstly,the changes of total acid,pH,reducing sugar,alcohol,amino acid nitrogen,NaCl and moisture were analyzed during the Tianbanzi fermention process,chili pei fermentation process and mixture fermentation process,respectively.For Tianbanzi fermtation,the total acid increased gradually and fermented 240d was 4 times as much as the initial fermentation stage.Amino acid nitrogen,it increased and then decreased.The content of reducing sugar increased and then the change tended to be gentle.For chili pei,the content of total acid at the end of fermentation was 2 times higher than that at the beginning of fermentation.The content of amino acid nitrogen fluctuated greatly,and its content reached the highest at 210 d.The content of reducing sugar decreased and then increased.The content of total acid increased at first and then decreased during mixture fermentation,and reached about 1.0159 g/100 g at fermented 180 d.For amino acid nitrogen,it increased and then decreased,and its content reached about 0.6086 g/100 g at 270 d.The content of reducing sugar increased and then the change tended to be gentle.Malic acid,citric acid and lactic acid are the main organic acid during the three different fermentation stages.The main organic acid was malic acid in Tianbanazi fermentation stage,the total contents of organic acid reached the highest at 60d.In the initial fermentation of chili pei,citric acid was the main organic acid,then lactic acid became the main organic acid at the latter fermentation stages,the total contents of organic acid reached the highest at 300d with the fermentation of chili pei,which was about 150.9 mg/100 g.With the fermentation process of mixture fermentation,the content of malic acid and lactic acid increased and then decreased,its content reached the hignest at 180 d.The total content of organic acid reached the highest at 180 d,and its content was about 284.0 mg/100 g.In this paper,the volatile compounds in the whole fermentation process of CBBPC were investigated by using HS-SPME and GC-MS.58 volatile compounds,68 volatile compounds and 60 volatile compounds were detected in Tianbanzi fermentation stage,chili pei fermentation stage and mixture fermentation stage,respectively.Aldehydes,esters and esters were the largest number of compounds during the three fermentation stages,which the number was 11,26 and 21,respectively.The results of comprehensive scores of principal volatile components showed that benzeneacetaldehyde,4-ethyl-2-methoxy-pheno and alcohol were the most important compounds during the three fermentation stages,respectively.Overall,the three kinds samples with most compounds are 60 d Tianbanzi,300 d chili pei,and 180 d mixture fermentation,respectively.The succession of bacterial community during the whole fermentation process of broad bean paste with chili was investigated by using PCR-DGGE.21 species,20 species and 22 species were subjected to preliminary identification for Tianbanzi,chili pei and mixture fermentation process,respectively.Lactobacillus siliginis,Klebsiella oxytoca,Klebsiella quasipneumoniae,Proteus mirabilis were the common bacterial in the three fermentation stages.Enterococcus faecium is unique in the fermentation stage of Tianbanzi.In addition,Bacillus sp.was only detected in the samples of Tianbanzi and mixture fermentation.Leuconostoc mesenteroides,Weissella confusa,Streptococcus pasteurianus,and Chroococcidiopsis thermalis were only detected in mixture fermentation stage.Stenotrophomonas maltophilia and uncultured bacterial only can be detected in the fermentation of chili pei.The results of CCA showed that total acid,NaCl and moisture are the important factors to affect the succession of bacterial community during the whole fermentation process.The primary flavor compounds of CBBPC were mainly contributed by Weissella,Staphylococcus,Leuconos,Leuconstoc,Lacobacillus and Bacillus.Interestingly,the dynamic changes of Bacillus and Tetragenococcus was highly related with salt.Lactobacillus and Enterococcus were responsible for acids production.Leuconostoc and Lactobacillus have a high correlation with the changes of amino acid nitrogen.For Tianbanzi fermentation process,lactic acid has high correlation with Leuconostoc,Bacillus and Lactobacillus.Malic acid and citric acid have high relationship with Leuconostoc,Staphylococcus and Bacillus.For chili pei fermentation process,lactic acid has high correlationship with Lactobacillus and uncultured bacterium,as well malic acid and citric acid have higher relationship with Klebsiella?Lactobacillu and Staphylococcus.During the mixture fermentation process,organic acids were mainly produced in the latter fermentation stage.What's more,lactic acid,citric acid and malic acid have high correlationship with Leuconostoc,Staphylococcus and Weissella. |
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