title: Effects of Aspergillus species inoculation and their enzymatic activities on the formation of volatile components in fermented soybean paste (doenjang).
abstract: The volatile components of rice-koji doenjang produced in association with various Aspergillus species (A. oryzae, A. sojae, and A. kawachii) during 8 weeks of fermentation were compared using gas chromatography-mass spectrometry analysis and multivariate statistical analysis. In addition, the activities of diverse enzymes (α-amylase, protease, lipase, and esterase) were determined to investigate their effects on the formation of volatile compounds. Regardless of the fungi types, carbonyls including 4-methylheptan-2-one, heptan-2-one, (E)-hept-2-enal, and hexanal were found to contribute mainly to early phase fermentation, whereas the contents of ethyl esters of long-chained fatty acids were considerably enhanced in the latter stage of fermentation. With the exception of α-amylase, the activities of the studied enzymes generally increased as fermentation proceeded, and there were significant differences in enzymes activities between the species of fungi. The lipase activity was strongly correlated with the formation of long-chain fatty acid esters, which could be related to the distinctive organoleptic properties of rice-koji doenjang.
authors.affiliation: Department of Food Science and Engineering, Ewha Womans University , 11-1 Daehyun-dong, Seodaemun-gu, Seoul 120-750, Republic of Korea.
authors.forename: Sun-Joo
authors.initials: SJ
authors.lastname: Kum
authors.forename: Seung-Ok
authors.initials: SO
authors.lastname: Yang
authors.forename: Sang Mi
authors.initials: SM
authors.lastname: Lee
authors.forename: Pahn-Shick
authors.initials: PS
authors.lastname: Chang
authors.forename: Yong Ho
authors.initials: YH
authors.lastname: Choi
authors.forename: Jae Jung
authors.initials: JJ
authors.lastname: Lee
authors.forename: Byung Serk
authors.initials: BS
authors.lastname: Hurh
authors.forename: Young-Suk
authors.initials: YS
authors.lastname: Kim
mesh_terms: D001230:Aspergillus / Q000201:enzymology / Q000378:metabolism*; D004950:Esterases / Q000378:metabolism; D005285:Fermentation; D005656:Fungal Proteins / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D008049:Lipase / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D045730:Soy Foods / Q000032:analysis / Q000382:microbiology*; D013025:Glycine max / Q000737:chemistry / Q000382:microbiology*; D055549:Volatile Organic Compounds / Q000032:analysis / Q000378:metabolism*; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D055549:Volatile Organic Compounds; D004950:Esterases; D008049:Lipase; D000516:alpha-Amylases; D010447:Peptide Hydrolases
keywords: Aspergillus species; enzymatic activities; metabolomics; rice-koji doenjang; volatile components