Evaluation of the Quality of Guinea Fowl (Numida meleagris) Eggs from Free-Range Farming Depending on the Storage Period and Age of Laying Hens.

ABSTRACT

The aim of the study was to determine the changes occurring in the eggs of helmeted guinea fowl (Numida meleagris) from free-range farming in relation to the laying season and storage time. The experimental material consisted of 360 guinea fowl eggs, collected in the first, second and third laying seasons and stored for 7, 14 and 21 days. After each period, physical and physicochemical characteristics of the eggs were determined, as well as the basic chemical composition and mineral content of the albumen and yolk and the yolk fatty acid profile. The age of the guinea fowls affected certain physical parameters of the eggs. The egg weight, shape index and shell thickness increased with the age of the laying hens; however, a decrease in the proportion of shell in the egg was demonstrated. Storage time had a significant effect on egg weight, weight loss during storage and air cell height. Significant differences were found in the chemical composition of guinea fowl eggs depending on the age of the laying hens. Eggs obtained from older laying hens were characterized by higher yolk fat content and lower ash content, while the albumen contained higher water content and lower ash content. During the three-year laying period, changes were observed in the mineral composition of the eggs. The fatty acid profile underwent significant changes; however, no important differences were observed in the total content of SFA, MUFA, PUFA and n-6 fatty acids. Conversely, significant differences were found for n-3 acids and the n-6/n-3 ratio. Eggs in the first and second laying seasons exhibited the most favorable composition. The slow dynamics of changes occurring in successive laying seasons and egg storage time indicated that the raw material studied was safe and could be used by consumers.