| Fermented chili sauce has a higher consumption demand in most areas of our country,and fresh chili in production and transportation is easy to be affected by the season,microorganisms,and not easy storage,it is relatively difficult to continuously produce chili sauce throughout the year.Using dried chili after rehydration as raw material for chili sauce processing can not only solve the problems of short shelf life and difficult transportation of fresh chili,but also realize the production of chili sauce in four seasons.The flavor of traditional fermented chili sauce is affected by natural and environmental microorganisms,and the quality is difficult to control.In order to keep the quality of chili sauce constant,bacteria are usually added artificially to homogenize the product flavor,shorten the fermentation time and improve economic benefits.Based on the research on the rehydration characteristics of dried chili peppers,this paper studied the changes of rehydration curve,texture and microstructure of different varieties of dried chili peppers during the rehydration process,fitted the rehydration dynamic models of different varieties of dried chili peppers,compared the contents of nutritive active substances and structural components of pepper after rehydration,and selected the optimal rehydration varieties of dried chili peppers by principal component analysis.The composite strains were inoculated and fermented,and compared with the same varieties of fresh chili sauce,the dynamic changes of quality during fermentation were studied.High-throughput sequencing was conducted on microbial community succession in the fermentation process to study the correlation between microbial community and key volatile components,providing reference for the development of refermented chili sauce.The main research results are as follows:(1)Selection of dried pepper varieties suitable for reprocessing with water: The structural characteristic values of Erjingtiao,Yan Pepper,Longji spicy pepper,Mei Pepper and Zhutous pepper were determined and the rehydration experiments were carried out.The empirical model of rehydration dynamics of Peleg showed that the equilibrium water content of five varieties of dried pepper were 6.0975,5.9737,6.1881,7.9681 and 4.2248,respectively.The results of scanning electron microscopy(SEM)and the texture characteristics of the samples during rehydration showed that the five dried capsicum exhibits the best texture characteristics and relatively complete and full cell structure without ulceration after rehydration for 90 min.Of five kinds of dry chili after water 90 min after physical and chemical properties were determined,the results show that the complex water two thorns contains high content of reducing sugar,total phenol content of flavonoids and cellulose,hemicellulose,and lignin and pectin content,principal component analysis comprehensive score is highest,showed that the complex water quality characteristics,as the subsequent fermentation processing of raw materials.(2)Taking fresh Vitex sinensis fermentation samples as reference,the improvement effect of sucrose addition on the fermentation quality of rehydrated Vitex sinensis complex strain was studied,and the quality variation rule was revealed in the fermentation process: Two strains of Lactobacillus plantarum XZ3 and Candida tropicalis,which were previously screened in the laboratory and suitable for capsicum fermentation,were inoculated and fermented on fresh and rehydrated capsicum.Fresh and rehydrated capsicum fermented capsicum A,B and C were obtained by adding 6%sucrose.There was no significant difference between C and A in sensory evaluation(p >0.05),but the scores of taste and aroma were significantly higher than those of B(p<0.05),indicating that the addition of sucrose could improve the sensory quality of Fushui Erjingtiao fermented chili sauce.The addition of sucrose can increase the contents of total acid,reducing sugar and amino acid nitrogen in the fermented hot pepper paste.The color difference of the two kinds of hot pepper paste is higher than that of fresh hot pepper paste.The p H values of the three kinds of chili sauce decreased during fermentation.The total acid content showed an opposite trend to p H.Reducing sugar content of A,B and C showed a decreasing trend.The contents of total flavonoids in A,B and C fluctuated,but there was no significant difference on the whole.The total phenol content increased slightly,the total A > B > C.4-coumarin was detected in both B and C,but not in A.Within 10 days of fermentation,A’s spiciness was 1.78 to 4.57,B’s was 3.06 to 6.06,and C’s was 2.59 to 4.54.The content of free amino acids in the three kinds of hot pepper sauces showed a decreasing trend during the fermentation process,but the proportion of essential amino acids in C was the highest,which was38.4% of the total amino acid content.(3)Correlation analysis between inoculated strains and key volatile components in three fermented hot pepper sauces: Through high-throughput sequencing study of microbial communities in the fermentation process of A,B and C,inoculated Lactobacillus plantarum XZ3 and Candida tropicalis became the absolute dominant strains in the microbial community on the second day of fermentation,and maintained steady state in the fermentation process.The content of volatile components reached the maximum at 6-8 days.The content of volatile components in rehydrated chili paste with sucrose was 3.27 times that without sucrose.Alcohols and esters became the most volatile components in the fermentation process and increased with the fermentation process.The OAV analysis showed that linalool,isoamyl alcohol and decaldehyde were the common key volatile components in the three chili sauces.N-heptanol,hexal,2-hexenal,phenylacetaldehyde and 2-methoxy-3-isobutylpyrazine are the characteristic aroma substances of A.2-nonenal is the characteristic aroma substance of B,which endowing B with floral and fragrant fragrance.Trans-2-decenoaldehyde is the characteristic aroma substance in C,giving C its citrus fruit aroma.The inoculated Lactobacillus plantarum XZ3 and Candida tropicum were positively correlated with the characteristic flavor substances of isoamyl alcohol,(+)-limonene and linalsol,while negatively correlated with the contents of nonaldehyde,phenacetaldehyde,hexal and2-hexenal in fermented chili sauce.The results showed that the composite strain fermentation enhanced the flavor characteristics and improved the safety of fermented chili products,which was suitable for the production of rehydrated chili sauce.At the same time,the addition of sucrose helped to improve the flavor and change the characteristic aroma of rehydrated chili sauce.In summary,it is suggested to use rehydrated Erjingtiao for complex strain fermentation,and add sucrose to achieve nutritional enhancement,enhance the senses,and make the flavor richer and more mature,so as to provide a reference for the production of fermented rehydrated chili paste. |
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