1H NMR AS A SIMPLE METHODOLOGY FOR BARN VS. FREE-RANGE CHICKEN EGGS DIFFERENTIATION

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  • Presentation type: Poster Presentation
  • Track: Poster Presentation
  • Keywords: caged hens; Metabolomic; Chemometrics;

Authors:

  • 1 Universidade Federal de Goiás
  • 2 Institute of Chemistry/Federal University of Goiás
  • 3 Instituto de Química / Universidade Federal de Goiás

1H NMR AS A SIMPLE METHODOLOGY FOR BARN VS. FREE-RANGE CHICKEN EGGS DIFFERENTIATION

GERLON DE ALMEIDA RIBEIRO OLIVEIRA

University of Brasília

Abstract

Chicken eggs are one of the main foods in the world, and the laying chickens are mostly raised in the intensive production system due to the rapid return on investment. This system provides cheap and safe eggs. On the other hand, it exposes animals to stress due to overcrowding on farms [1]. The growing concern with animal welfare has increased the demand for products from the extensive system. Eggs from different rearing systems anecdotally have morphological and sensory differences, such as yolk color and flavor. Some studies have already found differences between eggs from conventional and alternative rearing systems. However, they use time-consuming and environmentally unfriendly methodologies that are difficult to implement in routine quality control [2, 3]. This work compared the lipid composition of chicken egg yolks produced in the conventional system (from 16 farms/brands) with that of eggs produced by free-range chickens (from 6 rural properties), using 1H NMR and chemometrics. Sample preparation consisted of a single-step extraction with a CDCl3:D2O mixture, followed by centrifugation. This method was efficient in the discrimination (Fig. 1) since the eggs from free-range chickens showed more intense signals at  5.50 and especially at  2.85, which indicates higher contents of some polyunsaturated fatty acid (PUFA).

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Author

Pedro Henrique Soares Cardoso

Hello, Lorena. Thanks for the question. We can't relate these composition differences to the consumers' claimed sensory differences such as a thicker yolk and a stronger color and flavor for free-range eggs. The higher amount of PUFA probably wouldn't change the color, but some natural pigment due to the food of the hens. Also, we expect a higher amount of PUFA would decrease, and not increase the viscosity of the yolk.

Lorena Mara Alexandre e Silva

Nice. Thanks for your answere

 

Author

GERLON DE ALMEIDA RIBEIRO OLIVEIRA

Hi Lorena, thanks for your interest. Actually, the axis are just the areas of the two discriminant signals, after a normalization pretreatment. The previous chemometric tests revealed that these two signals were the most important in the discrimination, thus we plotted them alone and it was possible to discriminate the samples without a chemometric model.

 

 

Lorena Mara Alexandre e Silva

Ah yes. I understand now. Thanks for the answere.

Author

GERLON DE ALMEIDA RIBEIRO OLIVEIRA

Dear Elenilson, we are pleased to see your interest on our work, thanks very much!

About the questions: the graph is the dispersion of the values of the two variables (spectral area at 5.5 and 2.85 ppm) in the samples. Since these variables were found to have a great influence in the discrimination of the samples in the PLS-DA model, we tried to plot only them and see the dispersion. The area of the other signals were only used in the normalization of the data (unit vector normalization). Thus, although we performed chemometric analyses in order to find the best discriminat variables, we do not report these results here, since two variables were enough to the discrimination purpose. Thanks again.