Zein: the industrial protein from corn

Zein is the major storage protein of corn and comprises approximate to 45-5 0% of the protein in corn. It was first identified in 1897, based on its so lubility in aqueous alcohol solutions. Zein isolate is not used directly fo r human consumption due to its negative nitrogen balance and poor solubilit y in water. Current zein manufacture is limited to approximate to 500 tonne s per year from corn gluten meal. Zein sells for approximate to US$10-40 pe r kilogram, depending on purity. The ability of zein and its resins to form tough, glossy, hydrophobic grease-proof coatings and their resistance to m icrobial attack have been of commercial interest. Potential applications of zein include use in fiber, adhesive, coating, ceramic, ink, cosmetic, text ile, chewing gum and biodegradable plastics. These new applications of zein appear promising, but requires the development of low-cost manufacturing m ethods. This paper reviews the present status of the chemistry, properties, uses and methods of manufacturing zein. The characteristics of zein are di scussed in terms of its composition, structure, solubility in various solve nts and gelation properties. (C) 2001 Elsevier Science B.V. All rights rese rved.