Antioxidant properties of fermented soybean broth

Soybean broth (SB) and fermented soybean broth (FSB), at 100% exhibited goo d antioxidant activities of 0.85 and 0.80, respectively. Only FSB exhibited an excellent reducing power of 0.76-0.86 at 5-100%. FSB showed an excellen t scavenging activity on 1,1-diphenyl-2-picrylhydrazyl radicals (100%) at 2 0-100%, while SB only at 100%. FSB at 20-100% inhibited the production of s uperoxide anion radicals by 81-93% but SB showed no inhibition. As its conc entrations increased from 2-100%, the scavenging effect of FSB on hydroxyl radicals increased from 30-96%, whereas that of SB increased from 5-76%. Bo th FSB and SB were good chelators for ferrous ions. For cupric ions, SB sho wed significantly higher chelating effect than did FSB. These results showe d that FSB was superior to SB in most antioxidant properties and that SB an d FSB, more specifically FSB, might be potential antioxidants for applicati on in food products. (C) 2000 Elsevier Science Ltd. All rights reserved.