In addition, FSW extracts showed significantly higher (p < 0.05)
hydroxyl radical scavenging activity at concentrations of 0.08–
0.24 mg/ml (Fig. 3D). For USW and FSW, at 0.08 mg/ml, scavenging
hydroxyl radicals were 17.63 ± 0.75 and 65.09 ± 0.27%, respectively.
Higher hydroxyl radicals scavenging effect of FSW extracts
might be due to their higher contents of phenolics. In addition,
Iwai, Nakaya, Kawasaki, and Matsue (2002) reported that
low-molecular-weight viscous substances from Natto (a Chinese
fermented soybean) exhibited higher scavenging abilities on hydroxyl
radicals than high-molecular-weight viscous substances.
In addition, soybean broth fermented with Acetobacter sp., Lactobacillus
sp., Saccharomyces sp. and Streptomyces sp. showed better
scavenging abilities for hydroxyl radicals than unfermented
soybean broth (Yang et al., 2000). It seems that L. plantarum might
possess more hydroxyl radical scavenging components which
are formed during fermentation.