title: Effects of different rearing and feeding systems on lipid oxidation and antioxidant capacity of freeze-dried egg yolks.
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) were studied. Nine fresh egg yolks of each crossed treatment were pooled, frozen for a month, freeze-dried, vacuum-packed, and kept at -18 degrees 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, alpha-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 O(2)/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 7alpha-hydroxycholesterol, which was significantly lower in samples obtained with organic feed.
authors.affiliation: Dipartimento di Scienze degli Alimenti, Alma Mater Studiorum-Università di Bologna, 40127 Bologna, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pignoli
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Rodriguez-Estrada
authors.forename: Mara
authors.initials: M
authors.lastname: Mandrioli
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Barbanti
authors.forename: Laura
authors.initials: L
authors.lastname: Rizzi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Lercker
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D000975:Antioxidants / Q000032:analysis*; D002645:Chickens / Q000254:growth & development; D004041:Dietary Fats / Q000032:analysis; D004530:Egg Yolk / Q000737:chemistry*; D005612:Freeze Drying; D006799:Housing, Animal; D015227:Lipid Peroxidation; D014975:Lutein / Q000032:analysis; D013261:Sterols / Q000032:analysis; D024505:Tocopherols / Q000032:analysis
chemical_list: D000975:Antioxidants; D004041:Dietary Fats; D013261:Sterols; D024505:Tocopherols; D014975:Lutein