title: Fermentation temperature affects the antioxidant activity of the enzyme-ripened sufu, an oriental traditional fermented product of soybean.
abstract: In this study, sufu, a Chinese traditional fermented product of soybean, was prepared by ripening salted tofu cubes in the mash of Aspergillus oryzae-fermented rice-soybean koji possessing various hydrolytic enzymes at 25°C, 37°C and 45°C. Antioxidant activity including 2,2-diphenyl-2-picylhydoxyl (DPPH) radical-scavenging activity, Fe(2+)-chelating ability and reducing power exerted by the methanol extract of sufu was determined and compared with that of the non-fermented tofu extract. It was found that antioxidant activity of the sufu extracts was, generally, higher than the non-fermented tofu extract. Ripening temperature and the duration of ripening period affected the antioxidant activity of the sufu extracts. Taking into account of extraction yields, the sufu product ripened at 45°C for 16 days showed the most profound enhancement in the DPPH radical-scavenging effect and Fe(2+)-iron-chelating ability, which is 3.4 and 11.5 folds, respectively, that noted with the non-fermented tofu.
authors.affiliation: Graduate Institute of Food Science and Technology, National Taiwan University, Taipei 10673, Taiwan.
authors.forename: Yung-Hsin
authors.initials: YH
authors.lastname: Huang
authors.forename: Ying-Jang
authors.initials: YJ
authors.lastname: Lai
authors.forename: Cheng-Chun
authors.initials: CC
authors.lastname: Chou
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D001236:Aspergillus oryzae / Q000201:enzymology / Q000378:metabolism*; D001713:Biphenyl Compounds / Q000378:metabolism; D005591:Chemical Fractionation; D005285:Fermentation; D005516:Food Microbiology; D000432:Methanol / Q000737:chemistry; D010851:Picrates / Q000378:metabolism; D045730:Soy Foods / Q000382:microbiology*; D013025:Glycine max; D013696:Temperature
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl; D000432:Methanol