Study on selection of packaging materials and shelf life of protein-rich powder produced from the egg whites of salted duck eggs

Abstract

Egg whites of salted duck eggs are normally discarded in the separation of egg yolks. Most of the nutritional values of normal duck eggs are still retained in the egg whites of salted duck eggs. To make use of such egg whites, it is necessary to process the egg whites into a protein-rich powder, which can be used as a food processing material. Nevertheless, long-term storage of the egg white powder is challenging because this powder can easily absorb moisture, resulting in physical deteriorations (e.g: colour change), chemical alternation (e.g., protein and lipid degradation), and biological contamination (e.g., growth of yeasts and molds that produce toxic compounds). A study was conducted to test different types of packaging materials includingone-layered Polyethylene (PE) film, two-layered PE film, and three-layered films (PE, AL-Foil, BOPP/PE, Al/PE, BOPP/Al/PE, PET/Al/PE). The result shows that the most suitable packaging material for the protein-rich powder produced from egg whites of salted duck egg was two-layered AI/PE film. The quality of the product stored in  AI/PE film package remained nearly unchanged in 12 months, which proved safe to be used as food processing material.