Effect of dietary saffron (Crocus sativus L.) on the oxidative stability of egg yolk.

1. The effects of dietary inclusion of red stigmas of Greek saffron (Crocus sativus L.) on the oxidative stability of shell eggs and liquid yolks were investigated and compared with those of dietary a-tocopherol. 2. Ninety-six Lohmann laying hens, 38 weeks old, distributed into 4 groups with 4 replicates each, were given either a control diet, diets enriched with 10 (SAF10) or 20 (SAF20) mg/kg saffron, or a diet enriched with 200 mg/kg a-tocopheryl acetate (VE200). 3. Following 6 weeks of feeding, eggs were collected and the rate of lipid oxidation was determined in refrigerated stored shell eggs, as well as in yolks adjusted to a pH of 6.2 or 4.2 and stored in the presence of light. 4. The results showed that the extent of lipid oxidation in shell eggs, as measured by malondialdehyde (MDA) formation, differed between dietary treatments, but did not change with storage time. In stored shell eggs, MDA levels differed between dietary treatments at all time points. 5. Yolks from the control group adjusted to pH 6.2 gave MDA values higher than those of the SAF10 group, which in turn were higher than those of the SAF20 group, a finding suggesting that saffron exerted a dose-dependent antioxidative activity. The VE200 group gave lower MDA values than the other groups at all time points. The oxidation profile of yolks at pH 4.2 showed a similar pattern but the rate of oxidation was greater.