Study On Microbial Succession And Volatile Flavor Substance Changes Of Ciba-fermented Chili

Ciba chili is a kind of local chili product made by mixing dried chili with ginger and garlic after boiling.It is used in hot pot seasoning,home dishes and food.Because of its spicy stimulation and single aroma,Ciba chili has certain market limitations.in order to solve the above problems,this experiment used microbial fermentation technology to ferment Ciba chili,and compared the differences in physical and chemical properties,microbial flora structure and volatile flavor substances of Ciba chili during fermentation.two kinds of hot pot seasonings of fermented and non-fermented Ciba chili were fried.the color difference,viscosity,pungency and volatile flavor substances were compared,and the quality differences of hot pot seasoning before and after fermentation,during fermentation and stir-frying were compared.The findings are as follows :1.Physicochemical properties are important indicators in the fermentation process of Ciba chili.The p H value,salt content and water content will affect the growth and metabolism of microorganisms.the change trend of total acid content was related to the fermentation ability of microorganisms,and capsaicin had an effect on sensory perception.in this paper,the physical and chemical properties of Ciba chili were analyzed by Chinese standards.It was found that the p H value decreased from4.36 to 3.85 with the prolongation of fermentation time.total acid content increased from 8.2 ‰ to 20.3 ‰ with the extension of fermentation time.The water content and salt content fluctuate in a small range and there is no change trend and law.The content of capsaicin also showed a significant downward trend.with the extension of fermentation time,the content of capsaicin in Ciba chili decreased(from 0.48 g / kg to 0.36 g / kg),indicating that fermentation would reduce the spiciness of pepper and play an important role in easing the spicy taste of Ciba chili.2.The microbial flora structure and colony number can reflect the fermentation state of Ciba chili.in this paper,the microbial changes in the fermentation process of Ciba chili were studied by metagenomic sequencing technology and colony count determination method.The results showed that the total number of colonies and flora structure were a dynamic succession process during the fermentation of Ciba pepper.With the beginning of the fermentation of Ciba chili,the number of microorganisms began to increase greatly.Lactobacillus,as the dominant bacteria,accounted for 90 %of the relative abundance.After the metabolites reached the condition of inhibiting microorganisms,the fermentation reached the end point,the number of microorganisms decreased and the structure of the flora was stable.Bacterial strains including Lysinibacillus macroides,Providencia rettgeri,Bacillus clausii,Bacillus cereus,Bacillus sp and fungal strain Lentilactobacillus diolivorans were isolated from Ciba fermented chili.Studies have shown that metagenomics and 16 sr DNA single strain identification methods are suitable for the identification of flora structure and single colony in Ciba fermented chili.3.Volatile flavor is an important sensory quality of fermented ciba chili.In this paper,the flavor of Ciba fermented chili was successfully studied and compared by electronic nose technology,GC-MS technology and GC-IMS technology.The electronic nose had 18 sensors.The results showed that with the prolongation of fermentation time,the spicy taste stimulation decreased,the content of fermental alcohol compounds increased,and the spicy taste stimulation decreased.The results of GC-MS showed that the volatile flavor compounds of Ciba fermented chili were composed of esters,acids,alcohols,alkanes,olefins,ethers and a small amount of other flavor compounds.The relative content of acids and alcohols increased with the extension of fermentation time.The aroma characteristics of volatile flavor compounds were mainly citrus,lemon,distiller ’s yeast mellow,camphor and pine resin flavors,and mellow and acetic acid flavors were produced after fermentation.The results of GC-MS and GC-IMS showed that the volatile flavor compounds of the samples were basically the same but had different flavor characteristics due to the differences in the structure and content of volatile flavor compounds in different samples.The volatile flavor substances of Ciba chili during fermentation can be well separated by GC-IMS technology,and the diversity of volatile flavor substances can be directly seen.4.As a kind of food,the sensory quality is an important basic attribute of food.In this paper,colorimeter,viscometer,LC-MS,GC-MS and GC-IMS methods were used to determine the color,viscosity,pungency and volatile flavor substances of the two hotpot seasonings.The results showed that the color and capsaicin content of non-fermented hotpot seasoning were higher than those of fermented hotpot seasoning,and the viscosity was lower than that of fermented hotpot seasoning.Microbial fermentation causes carotenoids and capsanthin in pepper to be metabolized and degraded,and microbial metabolism during fermentation causes the dissolution of substances in Ciba chili.Therefore,the spicy taste of fermented hot pot seasoning is softer with fermented mellow and acetic acid flavor.The results showed that the Ciba chili not only had a unique mellow and acetic acid aroma but also reduced the spiciness of the pepper by microbial fermentation.The fermented hot pot seasoning processed by using fermented ciba pepper as raw material retains the unique volatile flavor of Ciba fermented chili,and the spicy taste is more gentle.Therefore,the microbial fermentation technology can obviously optimize the deficiency of the single aroma of Ciba chili and reduce the spiciness of Ciba chili.at the same time,it provides a data basis for the industrial production and product development of Ciba fermented chili.