Liquid egg products characterization during storage as a response of novel phyto-additives added in hens diet
This study aims to assess the effect of novel phyto-additives (bilberry leaves, walnut leaves, sea-buckthorn pomace and a mix of bilberry leaves, walnut leaves and sea-buckthorn pomace) added in hens diet on the liquid egg components (egg albumen, egg yolk and whole liquid egg) during storage. The phyto-additives added to the basic feed remarkably affected almost all the characteristics investigated, colour, pH and rheological behaviour of liquid egg products. The changes of egg yolk and albumen's colour and pH were not uniform. The supplementation of feeding with walnut leaves decreases significantly (p < 0.01) the luminosity of egg yolk, whereas the luminosity of egg albumen increases compared to the control. The pH values were influenced by the type of phyto-additive added in the hens diet, but its variations were only slightly dependent on the storage time of eggs. The rheological properties showed a pseudoplasticity of egg components depending on the hens diet and egg storage time. Ostwald-de Waele model fitted well with the rheological data, offering information on the changes of the apparent viscosity in relation to the diet type and storage time. The results indicated that these novel phyto-additives could be incorporated in hens diet for production of improved eggs quality and walnut leaves having a remarkable effect.