Eggshell and protein membrane separation

Eggshell and protein membrane separation is a recycling process. Nearly 30% of the eggs consumed each year are broken and processed or powdered into foods such as cakes, mixes, mayonnaise, noodles and fast foods. The US food industry generates 150,000 tons of shell waste a year. The disposal methods for waste eggshells are 26.6% as fertilizer, 21.1% as animal feed ingredients, 26.3% discarded in municipal dumps, and 15.8% used in other ways. Many landfills are unwilling to take the waste because the shells and the attached membrane attract vermin. Together the calcium carbonate eggshell and protein-rich membrane have no value or use. The invention of an eggshell and membrane separator has allowed for the recycling of these two valuable products.

Chicken eggshells are made up of 95% calcium carbonate by weight and the remaining material, 3.5%, is organic matrix.

The rich calcium carbonate shell has been used in the application for calcium deficiency therapies in humans and animals. A single eggshell has a mass of six grams which yields around 2200 mg of calcium. Eggshell particles are used in toothpaste as an anti-tartar agent. Powdered eggshells have been used for bone mineralization and growth.

Recent applications of eggshells in the form of calcium lactate has been used as a firming agent, a flavor enhancer, a flavoring agent, a leavening agent, a nutrient supplement, a stabilizer, and thickener. Eggshells are also used in as a calcium supplement in orange juice.

Eggshells have been incorporated into fertilizers as a soil conditioner. They have also been used as a supplement to animal feed. More recently the egg calcium carbonate particles have been used as coating pigments for ink-jet printing. Powdered eggshells are also used in making paper pulp. Recently eggshell waste has been used as a low cost catalyst for biodiesel production.

Joseph H. MacNeil, Professor of Food Science at Penn State University, developed a machine that uses a delicate multi-bladed knife to scrape the membrane from the surface of shell fragments. This invention uses a water-based method to separate the eggshell and protein membrane. The two products are processed in two streams to yield mm size particles of dry membrane and mm size particles of dried shell.

...
Wikipedia