For safety reason, EBN needs to be proper processed before the consumption by human [11]. As NANA and
citric acid are the most abundant soluble chemicals and therefore considered to be the targeted inhibitors. Here,
we aimed to reveal the amount of NANA and citric acid in EBN after standard processing procedures. Different
sample preparation procedures were applied onto EBN preparation to mimic the standard cooking processes.
The content of free NANA increased during the cooking processes, and an increase of ~4 folds after stewing in
different types of EBN (Supplementary Figure 1(a)). The increase could be an outcome of the release of conjugated
NANA as the free form after extensive cooking. In contrast, the content of citric acid dropped by 90%
after the processing (Supplementary Figure 1(b)), suggesting the free salt form of citric acid within EBN. Thus,
the cooking EBN could result in different amounts of NANA and citric acid.