Níveis de ácidos graxos e qualidade de ovos comerciais convencionais e enriquecidos com ômega-3

Abstract

1160 eggs were utilized in four experiments were conducted in Eggs Analyses Laboratory of the Institute of Animal Science of the Rural Federal University of Rio de Janeiro (UFRRJ) using commercial eggs produced by two groups of laying hens line Isa Brown with 33 weekold. In group 1, the birds were fed throughout their productive life with a basic diet of corn and soybean meal, while in group 2, since 22ª weeks-old of the hens, was added to the basic diet 1.5% of marine algae substrate and 1.8% fish oil (production of enriched ω-3 eggs). In experiment 1, whose aim was to evaluate the internal and external quality of conventional and enriched ω-3 eggs stored at different temperatures, it was found that both types of eggs studied had similar characteristics of internal and external quality. Eggs stored for 21 days at 25°C had lower averages for Haugh unit and yolk index and higher averages of albumen pH and yolk pH when compared to other treatments related to temperature and period of storage. There were no significant differences in egg shell thickness, shell weight and shell percentage between the two types of eggs stored for 21 days, regardless of the temperature of storage. In experiment 2 was assessed the influence of the season on the quality of enriched ω-3 eggs stored in refrigerated environment. In this second issue was verify that the eggs collected in the summer showed eggs weight and internal and external quality aspects lower than those collected in winter. In this second issue was verify that the eggs collected in the summer showed eggs weight and internal and external quality aspects lower than those collected in winter. In this second issue was verify that the eggs collected in the summer showed eggs weight and internal and external quality aspects lower than those collected in winter. The storage affected negatively the eggs weight, Haugh unit and yolk index, but there was no effect on the shell thickness. In experiment 3 was compared the fatty acids levels and relationships in conventional and enriched ω-3 eggs. The enriched ω-3 eggs showed total levels of ω-3 polyunsaturated (1839 mg/100g of yolk) and monounsaturated fatty acids (10,744 mg/100g of yolk) higher than those of conventional eggs (927 and 7997 mg/100g of yolk, respectively). Relations between polyunsaturated/saturated fatty acids (P/S) and between ω-6/ω-3 of enriched eggs were close to the ideal estimated for human consumption (1.10 and 3.00, respectively). The conventional eggs had total levels of saturated (8740 mg/100g of yolk) and ω-6 polyunsaturated fatty acids (9600 mg/100g of yolk) significantly higher than the enriched ω-3 eggs (6640 and 5510 mg/100g of yolk, respectively). In Experiment 4, three people individually assessed the intensity of yolk pigmentation with a color range. It was found that conventional eggs had the yolk less pigmented enriched ω-3 ones. The storage at different temperatures caused the appearance of dark spots in the egg yolks enriched. Based on the results obtained in experimental conditions used it was found that enriched ω-3 eggs showed high levels of ω-3 polyunsaturated fatty acids, appropriate balance of the relations between P/S and between ω-6/ω-3 and good characteristics of internal and external quality, thus those eggs can be considered an excellent alternative food for those consumers concerned about eating healthy diets.