CHAPTER 19: Value-added Uses of Eggshell and Eggshell Membranes
Published:01 May 2019
The chicken egg is a crucial source of high-quality human nutrition. Massive numbers of eggs are produced annually with a significant proportion (30%) being processed in industrial breaking plants, leading to the accumulation of eggshell (ES) and eggshell membrane (ESM) waste. ES and ESM byproducts generated by such facilities are often disposed of in landfills without pretreatment, which is not a green strategy. ES is the calcareous outer layer that is lined by the fibrous ESM; together they constitute around 10% of the egg weight. ES can be utilized for various applications as a source of calcium carbonate (CaCO3), calcium oxide, and, after transformation, hydroxyapatite. ES applications include food supplements, adsorbents, antimicrobial agents, soil amendments, catalysis, guided tissue regeneration (GTR), and CaCO3-based interventions. ESM is suitable for different applications in various formats, including intact, powdered, solubilized, and after digestion/hydrolysis. ESM-based applications include adsorption, chemical processing support, biosensors, and electrochemical cell production, along with medical technology, cosmetics, GTR, and drug mucoadhesion testing. Finally, ESM has been evaluated as an antibacterial, anti-inflammatory, antioxidant, and food supplement. The functional and structural characteristics of ES and ESM are the basis for a variety of value-added commercial products that are available or under development.