Fatty acid profile and sensory characteristics of table eggs procured from hens fed designer diets
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Omega-3 enriched eggs serve as an important functional food to boost consumption of polyunsaturated fatty acids (PUFA) critical for good health. Because omega-3 eggs have the potential for unpleasant aromas and flavours, this research was designed to assess the fatty acid profile and sensory attributes of eggs procured from hens consuming designer diets. In the first study, the use of hemp in hen diets led to significant increases in omega-3 PUFA content and colour intensity of yolks, but did not have adverse effects on the sensory profiles of cooked eggs. Additionally, the level of docosahexaenoic acid was the same in eggs from both the lowest and highest hempseed oil groups. In order to overcome this plateau, the second study assessed diets varying in linoleic acid (LA) content. Although docosapentaenoic acid in the yolk was significantly increased with an increasing dietary LA content, docosahexaenoic acid remained unaffected by dietary treatment. In the third study, a different approach was used to reduce competition between alpha-linolenic acid (ALA) and LA. Diets containing two levels of ALA and varying ratios of saturated fatty acids (SFA): LA + oleic acid (OA) were tested. Increasing dietary SFA: LA + OA resulted in marked increases in all n-3 PUFA. The fourth study was designed to assess the interaction between dietary constituents on sensory attributes of eggs, namely omega-3 PUFA from flaxseed oil (FO), and canola meal (CM), which contains precursors to trimethylamine, which may lead to fishy taint. Oceanic flavour significantly increased with inclusion of FO, while egg, creamy and buttery flavours showed a decrease. The pairing of CM and FO resulted in a significant decrease in egg flavour compared to using FO alone. This research has demonstrated that novel ingredients like hemp can be used in laying hen diets to deposit n-3 PUFA into eggs without fear of affecting sensory outcomes. Increasing the SFA: LA + OA ratio in layer diets is most effective in increasing yolk ALA conversion into long-chain PUFA. Lastly, CM should be added to diets with caution when used in conjunction with omega-3 PUFA ingredients due to a reduction in egg flavour.