Analysis Of Bacterial Diversity And Volatile Components In "Sanwei" Chopped Pepper During Storage

Pepper is one of people's favorite vegetables,and it is the second largest vegetable crop in China.China has become the largest producer,consumer,and exporter of peppers in the world.Various pepper products enrich people's material life.With the improvement of living standards,people begin to pursue low-salt green chopped pepper products.The "Sanwei" pepper in Taoling Township,Xintian County,Hunan Province are China's national geographical indication products.In recent years,the "Sanwei" pepper varieties have become impure and need to be purified and rejuvenated.Moreover,local traditional natural fermented chopped peppers are mostly high-salt products,which has affected the modern development of "Sanwei" pepper.This paper mainly analyzes the quality and processing characteristics of five different strains of "Sanwei" pepper in Taoling Township,Xintian County.In-depth discussion on the change of bacterial flora diversity before and after spoilage of low-salt fermented chopped peppers during storage,and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was used to analyze the changes of volatile components before and after spoiling chopped peppers.The main findings are as follows:In order to evaluate the quality and processing characteristics of "Sanwei" pepper of different lines in Xintian County,Hunan Province,five strains of "Sanwei" pepper,N351,N361,N3111,N3117 and N450,were selected to determine their fruit length,fruit quality,fruit width,flesh thickness,edible rate,hardness,color difference and nutritional indices(water content,soluble solids content,soluble sugar content,titratable acid content,vitamin C content,soluble protein content,total phenol content,capsaicin content).The method of principal component analysis was used to evaluate the score.The results showed that the comprehensive evaluation score sequence of five strains was N351>N361>N3117>N3111>N450 from high to low.The strain N351 has a high hardness(1285.00±17.02)g and a high soluble protein content(1.12%±0.06%),and is suitable as a raw material for fermented “Sanwei” peppers;The single fruit of strain N361 has large mass(15.94±0.58)g,high soluble solid content(9.33%±0.06%)and high soluble sugar content(3.54%±0.03%),suitable for fresh food;The strain N3117 has a high capsaicin content(1.81±0.06)mg/100 g and can be dried to make dried peppers..The results provided theoretical basis and data reference for the breeding and processing characteristics of geographical indication product "Sanwei" pepper.In order to explore the diversity of bacterial community structure during the storage of traditional fermented pepper,the high-throughput sequencing of Illumina Miseq was used to store the bacterial 16 S r RNA gene V4 in traditional fermented chopped pepper for 6 months,12 months,18 months and 24 months.The region was sequenced to analyze the bacterial community structure and diversity.The results showed that the abundance of the Firmicutes formed an absolute advantage,and the abundance reached 96% and 89%,respectively.The storage of the chopped pepper was 18 months and 24 months,and the thick-walled bacteria were stored for 6 months and 12 months.Firmicutes,Proteobacteria,Bacteroidetes and Verrucomicrobia are the main shared bacteria,and the relative abundance is between 15% and 35%.The bacterial diversity of the chopped pepper was similar for 6 months and 12 24 months,and the bacterial diversity was similar at 18 months and 24 months of storage,and the diversity of the flora increased.The pathogens such as Pseudomonas and Bacteroides were detected in the storage of chopped pepper for 18 months and 24 months.To some extent,these microorganisms are potentially harmful to chopped pepper.In order to study the difference of volatile components in low salt "Sanwei" chopped pepper during storage.the volatile chemical components of chopped pepper at four different storage time points(6 months,12 months,18 months,24months)were identified by headspace solid phase microextraction and gas chromatography-mass spectrometry.135 compounds of 11 kinds were detected in4 groups of chopped hot pepper samples,including 72 compounds in Y1,81 compounds in Y2,45 compounds in Y3 and 40 compounds in Y4.The results showed that the relative contents of acids in the four groups were 0.61%,4.71%,35.36% and 47.69%,respectively.In addition,the relative content of alkenes decreased and the species of alkenes decreased significantly after decaying.Alkanes and alkenes have similar results,and the relative content and species of alkanes are also significantly reduced.