According to Decker and Mei (1996) and Ke (2006), citric acid can be
used in food as a chelator of prooxidant metals. The chelating action of
the citric acid was investigated by Ke et al. (2009) in cooked
semitendinosus beef; control samples showed increased TBARS values
along the storage period, while samples containing citric acid had low
TBARS concentrations throughout storage. The authors also found that
high pH favors lipid oxidation, since samples with higher pH showed rapid TBARS formation. However the role of citric acid as antioxidant or
prooxidant in food will depend on its concentration and it effect on the
pH, there are studies reporting the prooxidant effect of low pH in muscle
foods (Ogden, Gurrero, Taylor, Buendia, & Gallardo, 1995; Ke et al.,
2009).