Influences of feed compositions on egg yolks in flavor characteristics and differences based on multi-omics analysis

Diet composition is a core factor regulating egg yolk flavor quality, and its formation mechanism is a research focus in food flavor science. However, studies on the effects of grain diets on the characteristic flavors of egg yolks are scarce. This study systematically analyzed the regulatory mechanisms of 3 diets (corn distillers dried grains with solubles (DDGS), corn-soybean meal and flaxseed) on egg yolk flavor using a combined sensory-flavor-metabolomics approach. The corn-soybean meal group (EY2) exhibited the highest sensory acceptability due to a balanced buttery-fat aroma profile characterized by high 3-pentanone, low grassy aldehydes, and a favorable palmitic acid/arachidonic acid ratio. The corn DDGS group (EY1) enhanced umami through small peptides and glutamic acid but developed off-flavors from lipid-oxidation-derived volatiles. The flaxseed group (EY3) exhibited high polyunsaturated fatty acids, yet ketone-mediated masking and phospholipid antioxidants produced a mild flavor profile. Glycerophospholipids and amino-acid metabolites synergistically shaped yolk flavor via lipid oxidation and Maillard reactions. These findings can provide new insights into diet-driven yolk-flavor formation and establish a scientific basis for precision-feed strategies to optimize egg nutritional and sensory quality.