Fatty acid profiles and volatile composition in the yolks of conventional eggs from seven different species (duck, free-range chicken, silky chicken, quail, pigeon, goose, and chicken) were compared using GC–MS and electronic nose (E-nose). The results showed that there were significant differences among the fatty acid profiles of the seven avian eggs. Goose eggs contained the highest contents of saturated and monounsaturated fatty acids but the lowest content of polyunsaturated fatty acids (PUFA), and the differences were significant (p<0.05). The PUFA proportion was the highest in the free-range chicken eggs of all the tested avian eggs. The ω-3 PUFA content and the ω-6/ω-3 ratio were significantly (p<0.05) higher in the yolks of goose and silky chicken. The volatile compositions of egg yolks are esters, alcohols, alkenes, and nitrogenous compounds, and the major compounds that contributed to discrimination of different species of eggs were ethyl acetate, pathalic acid butyl isohexyl ester, O-methylisourea hydrogen sulfate, 1-butanol, and N-isopropylbenzamide. In addition, seven different species of eggs were distinguished from each other through principal component analysis of E-nose data, suggesting that the E-nose may be a potential technology for discriminating different species of eggs.
Practical applications: The results showed that the major volatile components could be used as chemical markers to distinguish different species of eggs by the chemometric method. The results obtained from the electronic nose analysis agreed well with the GC–MS results, suggesting the potential application of the E-nose technique in the market quality control and the detection of counterfeit eggs.
Twenty-two fatty acids were detected and significant differences were found in the fatty acid proportions of different poultry eggs. A total of 41 volatiles were identified by GC–MS, and E-nose can successfully discrimination different species of eggs.