Dynamic changes in physicochemical property,biogenic amines content and microbial diversity during the fermentation of Sanchuan ham

Sanchuan ham is appreciated in Yunnan Province,China,for its characteristic flavor and taste,while the microbial community structure and biogenic amines content remain unclear during fermentation processes.In this study,we explored the physicochemical property,biogenic amines concentration and microbial diversity of external and internal Sanchuan ham by high-throughput sequencing during the processing of Sanchuan ham.Results showed that the nitrite remained at a stable level of 0.15 mg/kg which was significantly lower than the national health standard safety level of 20 mg/kg.In addition,compared with fresh hams,the content of total free amino acids in ripe Sanchuan ham has grown 14 folds;sour and bitter were the main tastes of Sanchuan ham.Notably,the concentration of cadaverine was the highest of all biogenic amines during the entire fermentation period.At the bacterial phyla level,Firmicutes and Actinobacteria were the two main phyla,while at the genus level,Staphylococcus was a significant strain throughout the whole fermentation.Moreover,the dry stage has a great impact on the succession change of microbial community structure.Simultaneously,the change trends and composition of bacteria in the interior have slight discrepancies with those of the exterior of Sanchuan ham.

Content Comparison of Three Kinds of Flavonoids in Powders of Tartary Buckwheat of Different Parts

The contents of rutin,quercetin and kaempferol in powders of tartary buckwheat of different parts were determined by high-performance liquid chromatography( HPLC). The results showed that the contents of the three kinds of flavonoids differed greatly in the powders of tartary buckwheat of different parts. The contents of rutin and quercetin in the powder of tartary buckwheat sprouts were significantly higher than those in the powders of tartary buckwheat leaves and seeds. The content of kaempferol was highest in the powder of tartary buckwheat seeds. It indicates that high-performance liquid chromatography can be used for quality control of tartary buckwheat powder for its time saving,cost saving and accurate and reliable results. The content of rutin in the powder of tartary buckwheat sprouts was highest,suggesting that it is more suitable for the development of various foods based on tartary buckwheat powder.

Relationship between microbial community and flavor profile during the fermentation of chopped red chili(Capsicum annuum L.)

To reveal the potential relationship between microbial community and flavor compounds during the fermentation of chopped red chili,microbial diversity and volatile metabolites at different stages were analyzed by high-throughput sequencing and gas chromatography-mass spectrometry.The results showed that Pseudomonas was the most dominant bacterial genus in fermented chopped red chili(FCRC),while unclassified_f__Nectriaceae and Colletotrichum were the most abundant fungal genus initially but were quickly replaced by Wickerhamomyces and Hyphopichia.Besides,citric acid and acetic acid were the most abundant organic acids,and esters were the dominant volatile flavor compounds in FCRC.Notably,the formation of flavor compounds in FCRC can be divided into three stages:the first stage is day 0,the second stage is day 3–10,and the third stage is day 15–20.Based on the O2PLS model,13 bacterial genera highly correlated(|ρ|>0.7)with flavor compounds and Exiguobacterium was correlated with 26 flavor components,having the largest numbers of correlated flavor compounds,while only four fungal genera correlated with flavor compounds(|ρ|>0.7)and unclassified_f__Nectriaceae was correlated with 11 flavor components.Moreover,the correlation analysis suggested that Exiguobacterium and Aureimonas were the core bacteria to produce the key flavors of FCRC,while unclassified_f__Nectriaceae,Wickerhamomyces and Hyphopichia were the core fungus.These findings provide novel insights into the variation of bacterial and fungal communities and increase our understanding of the core aroma-related microbiota involved in manufacturing FCRC with distinctive flavor properties.