The identification of antioxidants in dark soy sauce.
Soy sauce is a traditional fermented seasoning in Asian countries, that has high antioxidant activity in vitro and some antioxidant activity in vivo. We attempted to identify the major antioxidants present, using the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay as a guide. 3-Hydroxy-2-methyl-4H-pyran-4-one (maltol) was one of several active compounds found in an ethyl acetate extract of dark soy sauce (DSS) and was present at millimolar concentrations in DSS. However, most of the antioxidant activity was present in colored fractions, two of which (CP1 and CP2) were obtained by gel filtration chromatography. Their structural characteristics based on nuclear magnetic resonance (NMR) and electrospray-ionization time-of-flight mass spectrometry (ESI-TOF-MS) analysis suggest that carbohydrate-containing pigments such as melanoidins are the major contributors to the high antioxidant capacity of DSS.
Wang
Huansong
H
Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, 117597 Singapore.
Jenner
Andrew M
AM
Lee
Chung-Yung J
CY
Shui
Guanghou
G
Tang
Soon Yew
SY
Whiteman
Matthew
M
Wenk
Markus R
MR
Halliwell
Barry
B
D000085:Acetates / Q000737:chemistry; D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005504:Food Analysis / Q000379:methods*; D016166:Free Radical Scavengers; D009682:Magnetic Resonance Spectroscopy; D010455:Peptides / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011753:Pyrones / Q000737:chemistry; D045730:Soy Foods / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization
D000085:Acetates; D000975:Antioxidants; D016166:Free Radical Scavengers; D010455:Peptides; D011108:Polymers; D011753:Pyrones; C011908:melanoidin polymers; C008316:maltol