title: Changes in flavour and microbial diversity during natural fermentation of suan-cai, a traditional food made in Northeast China.
abstract: We measured changes in the main physical and chemical properties, flavour compounds and microbial diversity in suan-cai during natural fermentation. The results showed that the pH and concentration of soluble protein initially decreased but were then maintained at a stable level; the concentration of nitrite increased in the initial fermentation stage and after reaching a peak it decreased significantly to a low level by the end of fermentation. Suan-cai was rich in 17 free amino acids. All of the free amino acids increased in concentration to different degrees, except histidine. Total free amino acids reached their highest levels in the mid-fermentation stage. The 17 volatile flavour components identified at the start of fermentation increased to 57 by the mid-fermentation stage; esters and aldehydes were in the greatest diversity and abundance, contributing most to the aroma of suan-cai. Bacteria were more abundant and diverse than fungi in suan-cai; 14 bacterial species were identified from the genera Leuconostoc, Bacillus, Pseudomonas and Lactobacillus. The predominant fungal species identified were Debaryomyces hansenii, Candida tropicalis and Penicillium expansum.
authors.affiliation: College of Food Science, Shenyang Agricultural University, Shenyang 110866, PR China; Key Laboratory of Industrial Biotechnology, Ministry of Education, and School of Biotechnology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, PR China.
authors.forename: Rina
authors.initials: R
authors.lastname: Wu
authors.affiliation: College of Food Science, Shenyang Agricultural University, Shenyang 110866, PR China.
authors.forename: Meiling
authors.initials: M
authors.lastname: Yu
authors.affiliation: College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, PR China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Food Science, Shenyang Agricultural University, Shenyang 110866, PR China.
authors.forename: Lingshuai
authors.initials: L
authors.lastname: Meng
authors.affiliation: College of Food Science, Shenyang Agricultural University, Shenyang 110866, PR China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: College of Food Science, Shenyang Agricultural University, Shenyang 110866, PR China.
authors.forename: Yating
authors.initials: Y
authors.lastname: Xue
authors.affiliation: College of Food Science, Shenyang Agricultural University, Shenyang 110866, PR China. Electronic address: junruiwu@126.com.
authors.forename: Junrui
authors.initials: J
authors.lastname: Wu
authors.affiliation: College of Food Science, Shenyang Agricultural University, Shenyang 110866, PR China. Electronic address: yxqsyau@126.com.
authors.forename: Xiqing
authors.initials: X
authors.lastname: Yue
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D044822:Biodiversity; D002681:China; D005285:Fermentation; D005421:Flavoring Agents / Q000378:metabolism*; D005511:Food Handling; D005516:Food Microbiology; D005658:Fungi / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014675:Vegetables / Q000382:microbiology*
chemical_list: D005421:Flavoring Agents
keywords: Flavour; Microbial diversity; Natural fermentation; Suan-cai