title: Antioxidant changes of leek (Allium ampeloprasum var. porrum) during spontaneous fermentation of the white shaft and green leaves.
abstract: BACKGROUND
  Leek is grown for its thickened cylindrical white shaft made up of long leaf bases. Despite the potentially valuable nutritional profile of the green leaves, a large portion remains unused owing its restricted culinary applications. This large quantity of this plant biomass could be valorized given an adequate stabilization method. In this study, we examined leek fermentation with regard to antioxidant changes.
  
  
  RESULTS
  The oxygen radical absorbance capacity (ORAC) increased by 62% when the green leaves were fermented for 21 days, while 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity did not increase significantly. Fermentation resulted in an increase of endogenous polyphenolic compounds such as ferulic acid, astragalin, luteolin and naringenin. Moreover, fermentation stimulated the production of a series of polyphenolic compounds that were not present in the fresh leek. The flavour precursors in leek, i.e. methiin and isoalliin, were reduced by 91-93% and 100%, respectively, when spontaneous fermentation was allowed to occur on the white shaft and green leaves.
  
  
  CONCLUSIONS
  Our results demonstrated that application of fermentation resulted in a higher ORAC value and polyphenol content of the leek plant, especially in the green leaves. These results indicate the nutritional relevance of fermentation, which hold promise as a stabilization technique.
authors: Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium.
authors: Nathalie
authors: N
authors: Bernaert
authors: Dorrit
authors: D
authors: Wouters
authors: Luc
authors: L
authors: De Vuyst
authors: Domien
authors: D
authors: De Paepe
authors: Hervé
authors: H
authors: De Clercq
authors: Erik
authors: E
authors: Van Bockstaele
authors: Marc
authors: M
authors: De Loose
authors: Bart
authors: B
authors: Van Droogenbroeck
mesh_terms: D000490:Allium / Q000737:chemistry* / Q000382:microbiology; D000975:Antioxidants / Q000032:analysis* / Q000378:metabolism; D001530:Belgium; D003373:Coumaric Acids / Q000032:analysis / Q000378:metabolism; D003545:Cysteine / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism; D005285:Fermentation; D044950:Flavanones / Q000032:analysis / Q000378:metabolism; D005419:Flavonoids / Q000032:analysis* / Q000378:metabolism; D005519:Food Preservation; D058870:Food, Organic / Q000032:analysis / Q000191:economics; D005525:Food-Processing Industry / Q000191:economics; D006090:Gram-Negative Bacteria / Q000378:metabolism; D006094:Gram-Positive Bacteria / Q000378:metabolism; D007220:Industrial Waste / Q000032:analysis / Q000191:economics; D044949:Kaempferols / Q000032:analysis / Q000378:metabolism; D047311:Luteolin / Q000032:analysis / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry* / Q000382:microbiology; D018547:Plant Stems / Q000737:chemistry* / Q000382:microbiology; D012492:Salts / Q000737:chemistry
chemical_list: D000975:Antioxidants; D003373:Coumaric Acids; D044950:Flavanones; D005419:Flavonoids; D007220:Industrial Waste; D044949:Kaempferols; D012492:Salts; C017082:brine; C008389:methiin; C006453:alliin; C001579:astragalin; C004999:ferulic acid; C005273:naringenin; D003545:Cysteine; D047311:Luteolin