Change in alpha-tocopherol contents, lipid oxidation and fatty acid profile in eggs enriched with linolenic acid or very long-chain omega3 polyunsaturated fatty acids after different processing methods

The influences of dietary supplementation with alpha-tocopheryl acetate (alpha-TA) and of processing (by hard-boiling and scrambling) of eggs enriched with 3 fatty acids, either very long-chain 3 polyunsaturated fatty acids (VLC 3 PUFAs) or linolenic acid (LNA), on fatty acid composition, alpha-tocopherol content and lipid oxidation (thiobarbituric acid (TBA) values) were studied. Four dietary treatments were formulated from a basal diet containing linseed oil (LO) or fish oil (FO) combined with varying quantities of alpha-TA. Eggs from LO treatments were enriched with LNA and those from FO treatments were rich in VLC 3 PUFAs. Neither processing nor dietary supplementation with alpha-TA modified greatly the fatty acid profile of eggs. Dietary supplementation with -TA increased the alpha-tocopherol content of eggs. Eggs from FO treatments showed lower alpha-tocopherol content than those from LO treatments and processing of eggs enriched with VLC 3 PUFA reduced the alpha-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 with alpha-TA of feed supplemented the diet only in those eggs enriched with VLC 3 PUFA (from FO treatments).