1H NMR as a simple methodology for differentiating barn and free-range chicken eggs. (1st December 2022) - Cardoso, Pedro Henrique Soares
Graphical abstract: Highlights: A simple single-step extraction method was developed for 1 H NMR analysis of eggs. 1 H NMR lipidic profiles of free-range and conventional chicken eggs were compared. Eggs from free-range chickens had higher concentrations of ω-3 and ω-6 PUFAs. Free-range eggs showed a ratio between the signals at δ 2.85 and 4.14 of >0.14. Free-range eggs had higher concentrations and similar amounts of cholesterol. Abstract: The conventional intensive system produces cheap and safe chicken eggs, but exposes the animals to stress due to overcrowding on farms. This work compared the 1 H NMR lipidic profile of chicken eggs produced in conventional and free-range systems. Sample preparation consisted of a single-step extraction and centrifugation, and the 1 H NMR experimental time was just 3 min per sample. Eggs from free-range chickens had higher concentrations of ω-3 and ω-6 polyunsaturated fatty acids. The ratio between the signals at δ 2.85 and 4.14 from bis-allylic polyunsaturated fatty acids and glycerol moiety, respectively, was able to correctly classify 93.8 % of the samples. These results were similar to those of PLS-DA, used for comparative purposes. Therefore, the proposed method could be easily used to assist quality control and fraud prevention in the egg industry. Free-range eggs had higher concentrations of cholesterol but, as they are smaller, similar amounts to conventional ones.