Zein is a type of prolamin found in corn. It is usually made into a powder from corn gluten meal. Zein is one of the best-understood plant-based proteins. Pure zein is clear, odorless, tasteless, hard, water-insoluble and edible, with a variety of industrial and food uses.
Commercial use
Historically, zein has been used to make a variety of commercial products, including paper cup coatings, soda bottle cap linings, clothing fabrics, links, adhesives, coatings and adhesives. The main historical use of zein is in the textile fiber market, where it is produced under the name "Vicara". The use of zein in this market eventually disappeared as synthetic alternatives were developed. Through the use of electrospinning, zein fiber is once again being produced in the laboratory, and additional research will be conducted to re-enter the fiber market. It can be used as a water and grease coating for cardboard and allows recycling.
The properties of zein make it valuable to compete with insect shellac in processed foods and pharmaceuticals. It is now used as a coating for candies, nuts, fruits, pills, and other capsule foods and medications. In the United States, it may be labeled a "candy glaze" (which may also refer to a shellac-based glaze) and used as a coating for baked products or as a "vegetable protein." It is classified as Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration. For pharmaceutical coatings, zein is preferred over food shellac because it is all-natural and requires less testing per USP monograph.
Zein can be further processed into resins and other bioplastic polymers, which can be extruded or calendered into a variety of plastic products. With growing concerns about the environmental concerns of synthetic coatings such as PFOA and current increases in hydrocarbon petrochemical prices, there is growing interest in zein as a raw material for a variety of non-toxic and renewable polymer applications, particularly It's in the paper industry. Reasons for the renewed interest in zein include concerns about the cost of plastic going to landfills and consumer interest in natural substances. There are also many potential new food industry applications.
From the perspective of application types of coatings and films
Researchers at the University of Illinois at Urbana-Champaign and the William Wrigley Jr. Company have recently been studying the possibility of using zein to replace part of the gum base in chewing gum. They are also working on medical applications, such as using zein molecules to "carry biological compounds to target sites in the body." Zein-based packaging could have many potential food safety applications, several researchers said. A military contractor is looking into using zein to protect MRE food packaging. Other packaging/food safety applications that have been studied include frozen meals, ready-to-eat chicken, cheese and liquid eggs. Food researchers in Japan noticed that the zein molecule has the ability to create a water-resistant barrier.
While zein has many existing and potential uses, until recently, its historically high cost has been a major obstacle to greater commercial success. Zein prices are now very competitive with food shellac. Zein can be extracted as a by-product of the ethanol manufacturing process or in new offshore manufacturing processes.
