Abstract
Production and processing of chicken eggs is a significant segment of the food industry, not only in the EU, but also globally, with a leading position of China reaching almost 40 % of global chicken eggs production. Egg processing industry generates a huge amount of waste in the form of eggshells and membranes that make up the share of about 11 % wt. of the egg. The utilization of this waste is low and often is only landfilled without further use or refinement to more valuable products.
The waste egg-shells and membranes can be used in their native or modified form. Among the main ways of usage belongs adsorbents (in particular for waste water), heterogeneous catalysts, fertilizers, additives for correction of the acidic soils pH, food supplements, bone implants components or cosmetics products components. Nevertheless, eggshells are recycled only rarely.
Utilization of waste consisting of eggshell in pharmacy is limited mainly by the presence of unwanted egg-white and other impurities. For pharmaceutical use, the feedstock must contain only minimal amount of contaminating proteins. Egg-white and other impurities must be removed e.g. by washing prior to further processing of shells and membranes.
For optimization of the parameters of the egg-white washing, the design of experiments (DOE) methodology in the form of a central compositional plan was chosen, to achieve rapid and effective washing out under optimal conditions. The protein concentration was measured photometrically by Biuret method. By iterative response surface analysis, statistically insignificant factors and their interactions were excluded. A model that is adequate and can be used to describe the process of removing undesirable substances from waste consisting of eggshell and membranes by washing was obtained.
