Paper and Paperboard
Zein is used for sizing, impregnating, coating, laminating, and gluing paper. One of the uses is as a glossy protective coating, which is applied as Zein varnish and known as overprint or label varnish. It gives a glossy finish and resists scuffing, water, alcohol and grease.
Zein is resistant to penetration by the oils and greases, making it ideal to coat cardboard containers for greasy foods. Food containers remain biodegradable with a zein coating, unlike boxes treated with wax.
Zein has been used to produce polymeric films that are biodegradable and can be used as a coating to protect food and related materials from spoilage. Zein films can replace commercial coating agents, like carnauba wax and shellac, inside food packets. The properties of the films, like biodegradability, mechanical properties, water absorption, barrier properties, etc., largely depend on the interaction between local existent proteins, plasticizers and other functional groups.
Zein is being added to printing ink to reduce the drying time and improve the rub resistance of ink applied to a variety of materials. Since Zein is a food ingredient, it can be used with edible inks.