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), was 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 meq 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.
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
2009
Abstract
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), was 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 meq 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
