OA has been reported as the most potent inhibitor among a
number of dicarboxylic acids by Son and others (2001). The ability
of carboxylic acids to inhibit browning depends on their chemical
structure. Inhibitory effects of dicarboxylic acids decreases with
increasing chain length and dissociation constants, signifying the
possible role of steric interference in the interaction of the longer
chains with the enzyme and of the degree of their ionisation in
solution. OA has been shown to reduce the rate of phenol oxidation
in the presence of hydrogen peroxide, iron and copper due to its
chelating ability and lowering of pH (Kayashima & Katayama,
2002). When present in the human diet, OA may combine with
essential minerals such as calcium, iron, magnesium, and potassium
to form less soluble salts known as oxalates and hinder the
bio-availability (Palaniswamy, Bible, & McAvoy, 2004). This fact,
together with our study, suggests that treatment with OA is safe
and seems to be a promising method for controlling browning in
minimally processed fresh-cut lettuce.