Comprehensive multi-omics analysis reveals key metabolites and lipids driving flavor development in quail egg yolk

Quail yolk flavor is shaped by genetic and seasonal factors, but the underlying biochemical mechanisms remain unclear. Here, we applied integrated lipidomic and volatilomic analyses to investigate breed- and season-specific volatile formation D-type (egg-type, "Shendan No.1", selected for high egg production) and R-type (meat-type, French giant meat quail, selected for rapid growth and meat production) quail yolks. A total of 161 volatiles were identified. D-type yolks were enriched in acetic acid butyl ester, 3-methyl-butanoic acid butyl ester, 1-(4-methylphenyl)-ethanone, and nonanal, contributing a mild fatty-floral aroma with fruity, sweet, and green notes, whereas R-type yolks contained higher 5-methyl-2-(1-methylethyl)-cyclohexanone and 1-octen-3-ol, producing a roasted-nutty profile. Seasonal analysis showed that trans-2,4-decadienal and 4-methoxybenzaldehyde preserved D-type aroma in autumn, while 1-methyl-1H-pyrrole-2-carboxaldehyde accumulated in R-type yolks, enhancing roasted-nutty characteristics. Lipidomic profiling revealed polyunsaturated fatty acids, especially linoleic and linolenic acids, as key drivers of volatile formation via lipid remodeling and metabolic interactions. These findings provide mechanistic insights into yolk flavor differentiation and inform strategies for improving quail egg quality.