HDMF
and HMF in soy sauce are formed chemically by the
Maillard reaction between sugars and amino acids during
heating processes, such as the heat treatment of raw materials
and the pasteurization of liquid part of mash (29, 30).
These furanones were investigated for their antioxidative
activities. HMF and HDMF, as well as HEMF, were found
to be antioxidants (Table 4). The order of potency is HEMF
> HDMF > HMF. HEMF and HDMF are more potent than
ascorbic acid. These furanones inhibit lipid peroxidation by
oxygen radicals. HEMF scavenges singlet oxygen and its
scavenging potency is greater than that of methionine, a
singlet oxygen scavenger (data not shown).