The influence of the addition of metal chelators on oxidative stability was studied in a milk drink and in a mayonnaise system containing highly polyunsaturated lipids. Milk drinks containing 5% (w/w) of specific structured lipid were supplemented with lactoferrin (6-24 M) and stored at 2 C for up to 9 weeks. Mayonnaise samples with 16% fish oil and 64% rapeseed oil (w/w) were supplemented with either lactoferrin (8-32 M), phytic acid (16-124 M), or EDTA (16-64 M) and were stored at 20 C for up to 4 weeks. The effect of the metal chelators was evaluated by determination of peroxide values, secondary volatile oxidation products, and sensory analysis. Lactoferrin reduced the oxidation when added in concentrations of 12 M in the milk drink and 8 M in the mayonnaise, whereas it was a prooxidant at higher concentrations in both systems. In mayonnaise, EDTA was an effective metal chelator even at 16 M, whereas phytic acid did not exert a distinct protective effect against oxidation. The differences in the equimolar effects of the metal chelators are proposed to be due to differences in their binding constants to iron and their different stabilities toward heat and low pH.
|Journal||Journal of Agricultural and Food Chemistry|
|Publication status||Published - 2004|