3.2. Effect of organic acids during the soaking process on the reduction
of AFs
The general cooking recipe of soybean-based foods in East Asia
includes a soaking process for 6 or 18 h in water, depending on the
season. In the present study, the treated concentration of organic
acid was determined by the degree of the discoloration of the soybeans.
When organic acids higher than 1.0 N were added to the
soybeans, the discoloration occurred. The reduction rates of AFs
in the contaminated samples with distilled water and organic acid
solutions such as citric acid, lactic acid, succinic acid, and tartaric
acid during the soaking process were shown in Table 2. The reduction
rates of AFB1 in distilled water (control) for 6 h and 18 h were
58.1% and 62.0%, respectively. The reduction rates of AFB1 in all
1.0 N organic acids for 6 h and 18 h were significantly different
from the reduction rates in distilled water, except for 1.0 N succinic
acid (p < 0.05). The reduction rates of AFB1 in 1.0 N citric acid and
1.0 N tartaric acid for 18 h were 94.1% and 95.1%, respectively.
However, the mean of the reduction rate of AFB1 during the soaking
process with 1.0 N succinic acid was 58.5% for 6 h and 62.0% for
18 h.
According to Mutungi, Lamuka, Arimi, Gathumbi, and Onyango
(2008), the reduction rate of AFs in contaminated maize during