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Effects of Different Rearing and Feeding Systems on Lipid Oxidation and Antioxidant Capacity of Freeze-Dried Egg Yolks

Pignoli, Giovanni, Rodriguez-Estrada, Maria Teresa, Mandrioli, Mara, Barbanti, Lorenzo, Rizzi, Laura, Lercker, Giovanni
Journal of agricultural and food chemistry 2009 v.57 no.24 pp. 11517–11527
rearing, poultry production, hen feeding, lipid peroxidation, antioxidant activity, freeze drying, dried eggs, egg yolk, food analysis, food composition, nutrient content, nutritive value
Lipid oxidation and antioxidant capacity of freeze-dried egg yolks produced with two rearing systems (battery cages and free-range) and two types of feedings (conventional and organic) were studied. Nine fresh egg yolks of each crossed treatment were pooled, frozen for a month, freeze-dried, vacuum-packed, and kept at −18 °C until analysis. No significant differences were observed in the lipid (58.0−62.1%) and total sterol contents (33.0−35.5 g/kg of lipids) of the freeze-dried egg yolks. Free rearing and conventional feeding systems resulted in significantly higher total tocopherol, α-tocopherol, and lutein contents, as compared to the battery cage and the organic feed, respectively. However, no significant differences were found in lipid oxidation (peroxide value = 0.7−0.9 mequiv of O2/kg of fat; thiobarbituric reactive substances = 1.0−1.3 mg of malonylaldehyde/kg of sample) and cholesterol oxidation (28.8−43.5 mg of cholesterol oxidation products/kg of lipids; 0.08−0.12% oxidized cholesterol) of freeze-dried egg yolks except for 7α-hydroxycholesterol, which was significantly lower in samples obtained with organic feed.