title: Selection of functional lactic acid bacteria as starter cultures for the fermentation of Korean leek (Allium tuberosum Rottler ex Sprengel.).
abstract: The purpose of this research was to find safe and suitable starter cultures for the fermentation of Korean leek (Allium tuberosum Rottler), also known as garlic chives or Oriental garlic. This traditional herb has several functional properties and a strong flavour; its leaves are used as food material. Eighteen strains of lactic acid bacteria (LAB) were isolated from well-fermented leek kimchi. Controlled fermentation of the leek leaves was conducted with 2 strains (Weissella confusa LK4 and Lactobacillus plantarum LK8), selected as potential starter cultures on the basis of their safety properties, and on the pH, total titratable acidity (TTA), and viable cell numbers [colony forming units (CFUml(-1))] achieved during the fermentation. Microbial dynamics was also followed during fermentation by using PCR-DGGE (Denaturing Gradient Gel Electrophoresis) on DNA level. To analyse bioactive compounds such as thiols and allicin (diallyl thiosulfinates), the total flavonoid and polyphenolic contents were determined by colorimetric methods. Functional properties were assessed on the basis of anti-oxidative capacities by determining the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging effect, and ferric reducing antioxidant power (FRAP). W. confusa LK4 rapidly increased during the first stage of leek fermentation, and was mainly responsible for accelerated fermentation during the early period in contrast to L. plantarum LK8, a stronger acid producer during the later stages of fermentation. After 48 h fermentation, leeks fermented with W. confusa LK4 showed the highest radical scavenging effects and reducing ability. The detectable amount of allicin of fermented leeks decreased relative to the change in pH, whereas the concentration of thiols significantly increased. Total flavonoid and poly-phenolic contents changed during fermentation and showed correlation with anti-oxidant effects. We therefore suggest the suitability of W. confusa LK4 as a potential starter culture for fermentation of leeks.
authors.affiliation: School of Life Sciences, Handong Global University, Pohang, 791-708 Gyeongbuk, South Korea.
authors.forename: Jaesik
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Life Sciences, Handong Global University, Pohang, 791-708 Gyeongbuk, South Korea; Graduate School of Advanced Green Energy and Environment (AGEE), South Korea.
authors.forename: Yosep
authors.initials: Y
authors.lastname: Ji
authors.affiliation: School of Life Sciences, Handong Global University, Pohang, 791-708 Gyeongbuk, South Korea; Graduate School of Advanced Green Energy and Environment (AGEE), South Korea.
authors.forename: Hyunjoon
authors.initials: H
authors.lastname: Park
authors.affiliation: School of Life Sciences, Handong Global University, Pohang, 791-708 Gyeongbuk, South Korea.
authors.forename: Jieun
authors.initials: J
authors.lastname: Lee
authors.affiliation: School of Life Sciences, Handong Global University, Pohang, 791-708 Gyeongbuk, South Korea; Graduate School of Advanced Green Energy and Environment (AGEE), South Korea.
authors.forename: Soyoung
authors.initials: S
authors.lastname: Park
authors.affiliation: School of Life Sciences, Handong Global University, Pohang, 791-708 Gyeongbuk, South Korea.
authors.forename: Soyoung
authors.initials: S
authors.lastname: Yeo
authors.affiliation: School of Life Sciences, Handong Global University, Pohang, 791-708 Gyeongbuk, South Korea.
authors.forename: Hyunkil
authors.initials: H
authors.lastname: Shin
authors.affiliation: School of Life Sciences, Handong Global University, Pohang, 791-708 Gyeongbuk, South Korea; Graduate School of Advanced Green Energy and Environment (AGEE), South Korea. Electronic address: wilhelm@woodapple.net.
authors.forename: Wilhelm H
authors.initials: WH
authors.lastname: Holzapfel
mesh_terms: D000975:Antioxidants / Q000032:analysis; D001713:Biphenyl Compounds / Q000032:analysis; D058645:Denaturing Gradient Gel Electrophoresis; D005285:Fermentation; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D048191:Lactiplantibacillus plantarum / Q000378:metabolism*; D019697:Onions / Q000382:microbiology*; D010851:Picrates / Q000032:analysis; D013438:Sulfhydryl Compounds / Q000032:analysis; D058836:Weissella / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D010851:Picrates; D013438:Sulfhydryl Compounds; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: Allium tuberosum; Anti-oxidant capacity; Korean leek; Lactic fermentation