304 Emir. J. Food Agric ● Vol 31 ● Issue 4 ● 2019 Liquid egg products characterization during storage as a response of novel phyto-additives added in hens diet Tatiana Dumitra Panaite 1 , Silvia Mironeasa 2 *, Mădălina Iuga 2 , Petru Alexandru Vlaicu 1 1 National Research and Development Institute for Animal Biology and Nutrition (IBNA), Romania, 2 Ştefan cel Mare University, Faculty of Food Engineering, Str. Universităţii nr. 13, 720229, Suceava, Romania *Corresponding author: Silvia Mironeasa, Ştefan cel Mare University, Faculty of Food Engineering, Str. Universităţii nr. 13, 720229, Suceava, Romania. Tel: + 40 230 216 147; + 40 741 985 648. E-mail: silviam@fa.usv.ro; silvia_2007_miro@yahoo.com Received: 11 February 2019; Accepted: 22 April 2019 INTRODUCTION Eggs, known as unique food material, represent a rich source in high-quality proteins, unsaturated fatty acids, phospholipids, minerals, vitamins and lipophilic pigments including antioxidant carotenoids (Huopalahti et al., 2007). After breaking the shell, the basic components obtained are egg albumen which portion makes up 60% of the egg’s weight and yolk egg that represents approximately 35% of the liquid egg. The albumen and yolk egg have many functional properties which mainly depend on the quality of their proteins (Mine, 2002). As multifunctional food materials, due to their nutritional and functional properties, eggs are incorporated in various food systems, increasing their nutritional value, improving color and favor. Egg is used as ingredient in bakeries, biscuits, pasta e.g., (Stadelmann and Cotterill, 1995). In recent years, egg consumption in the form of egg components has increased compared to marketed shell eggs (Jesús et al., 2013). The egg components characteristics such as colour, pH and viscosity are infuenced by the diet administered to laying hens (Lomakina and Mikova, 2006). The carotenoids, particularly lutein and zeaxanthin and xanthophylls with their antioxidant effects infuenced the colour of egg yolk (Kopřiva et al., 2014). Also, the housing system has a signifcant effect on the yolk colour (Sokołowicz et al., 2018).The pH affected the thinning of the thick albumen (Burley and Vadehra 1989; Kato et al., 1970) and is being used to assess thick albumen thinning (Beveridge and Nakai, 1975). The viscosity depends also on the storage time and temperature, water content and egg stress. Several tests have been made to reestablish the egg consumption by modifying egg composition through feeding nutritionally-changed diets. The supplementations of the hens diet with phytonutrients can remarkable affect on the quality of eggs (Nour et al., 2018; Dvořák et al., 2017). Several reports have described the effect of different feed additives in laying hens fed diet on egg quality (Świątkiewicz et al., 2018; Arpášová et al., 2012). The phytochemicals, like phenolic compounds, are considered beneficial for both human and animal health (Silva et al., 2006). 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 signifcantly (p < 0.01) the luminosity of egg yolk, whereas the luminosity of egg albumen increases compared to the control. The pH values were infuenced 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 ftted 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. Keywords: Colour parameters; Eggs; pH; Phyto-additives; Rheological properties Emirates Journal of Food and Agriculture. 2019. 31(4): 304-314 doi: 10.9755/ejfa.2019.v31.i4.1937 http://www.ejfa.me/ RESEARCH ARTICLE ABSTRACT