Change in α-tocopherol contents, lipid oxidation and fatty acid profile in eggs enriched with linolenic acid or very long-chain ω3 polyunsaturated fatty acids after different processing methods

The influences of dietary supplementation with α-tocopheryl acetate (α-TA) and of processing (by hard-boiling and scrambling) of eggs enriched with ω3 fatty acids, either very long-chain ω3 polyunsaturated fatty acids (VLC ω3 PUPAs) or linolenic acid (LNA), on fatty acid composition, α-tocopherol content and lipid oxidation (thiobarbituric acid (TBA) values) were studied. Four dietary treatments were formulated from a basal diet containing 40 g kg-1 linseed oil (LO) or fish oil (FO) combined with either 0 or 100 mg α-TA kg-1 of feed. Eggs from LO treatments were enriched with LNA and those from FO treatments were rich in VLC ω3 PUPAs. Neither processing nor dietary supplementation with α-TA modified greatly the fatty acid profile of eggs. Dietary supplementation with α-TA increased the α-tocopherol content of eggs (187.2 versus 407.9 μg g-1 dry matter). Eggs from FO treatments showed lower α-tocopherol content than those from LO treatments (273.5 versus 321.6 μg g-1 dry matter), and processing of eggs enriched with VLC ω3 PUFA reduced the α-tocopherol content by a significant 16%. Moreover, processing of eggs increased lipid oxidation two- to nine-fold. Oxidation levels of hard-boiled eggs were 30.4% higher than those of scrambled eggs. TBA values in hard-boiled and scrambled eggs were significantly reduced when 100 mg α-TA kg-1 of feed supplemented the diet only in those eggs enriched with VLC ω3 PUFA (from FO treatments). © 2003 Society of Ghemical Industry.