Production and Application of trans, trans CLA-rich Eggs: Chemical and Physiological properties and Prospects for Value-added Foods

Conjugated linoleic acid (CLA) is an 18-carbon fatty acid with conjugated double bonds that is naturally present in beef and dairy products. Certain CLA isomers exhibit human bioactivity such as anti-obesity and muscle metabolism effects, as well as prevention of age-associated conditions, and improved immune and inflammatory responses. However, an individual needs to consume 3-4 g CLA/day to realize these potential health benefits, and a Western diet only provides a tenth of this recommendation. Chicken eggs have been used as a commercialized vehicle to deliver other bioactive lipids such as omega-3 fatty acids, because the lipid profile of the egg yolk is easily modified through dietary inclusion. Therefore, eggs may also be suitable for delivering additional CLA to a person's diet so they may realize the potential health benefits. This program of study explored the use of a novel CLA-rich soy oil in poultry diets to produce CLA-rich eggs and determine their specific physiochemical properties. In addition, CLA-rich eggs were used to prepare CLA-rich mayonnaise and egg patties in order to determine the extent of CLA-rich egg use as a functional ingredient. The overall objectives were: 1) Describe efficient methodology for the analysis of egg yolk lipids. 2) Determine the CLA accumulation in eggs in layer hens, breeder hens and jungle fowl. 3) Determine the effect of CLA accumulation in egg yolk lipids on fatty acid composition of egg yolk triacylglycerides and phospholipids relative to those in conventional eggs. 4) Determine the effect of CLA in egg yolks on physical, rheological and egg quality properties. 5) Determine the functional effect of CLA rich eggs on the quality of processed food, and their physiochemical properties. This dissertation includes nine chapters on the novel findings from producing CLA-rich eggs. One CLA-rich egg can provide 140 mg additional CLA to the diet, a tablespoon of CLA-rich mayonnaise can provide 1.8 g of CLA, and a fried egg sandwich combining all of these ingredients can provide 2.8 g of CLA. Moreover, this research provided current egg literature with a comprehensive description of yolk lipid modifications that result from CLA incorporation, effects on egg quality, and use of CLA-rich eggs in food production.