Biodegradable edible films can be made from corn protein, α-zein. Pure zein films are cast from an organic solution of α-zein. This report outlines the surface conditions of such pure zein films. First, the transition temperature, T t′ of the pure zein film was measured with a thermomechanical analyzer. T t was between 167.0 and 172.7°C. The thermal elongation of the films depended on the drying conditions used during film preparation. Second, the surface microstructure of pure zein films, produced under several different drying conditions, was observed by atomic force microscopy. The surface had a morphology that showed depressions either with acutely (90–120°) or obtusely (121–180°) angled features depending upon the drying conditions. On the other hand, the surface microstructure after thermal elongation analysis appeared to have a pattern of projections that was repeated every 25 nm. Third, we measured the contact angle of the pure zein films. We found a correlation between surface microstructure and contact angle. Pure zein films with projections smaller than 200 nm in base diameter on the surface had a high contact angle (>70°).
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Price excludes VAT (USA)
Tax calculation will be finalised during checkout.
Japan Chemical Industry Association, A Study on Hormone-Like (Hormone-Mimic) Effects of Exogenous Substances—Shortened English Version, Japan Chemical Industry Association, Tokyo, 1997.
Krochta, J.M., Edible Protein Films and Coatings, in Food Proteins and Their Application, edited by S. Damodaran and A. Paraf, Marcel Dekker, Inc., New York, 1997, pp. 529–549.
Cuq, B., N. Gontard, and S. Guilbert, Proteins as Agricultural Polymers for Packaging Production, Cereal Chem. 75:1–9 (1998).
Argos, P., K. Pedersen, M.D. Marks, and B.A. Larkins, A Structural Model for Maize Zein Proteins, J. Biol. Chem. 257:9984–9990 (1982).
Shewry, P.R., and A.S. Tatham, The Prolamin Storage Proteins of Cereal Seeds: Structure and Evolution, Biochem. J. 267:1–12 (1990).
Yamada, K., H. Takahashi, and A. Noguchi, Improved Water Resistance in Edible Zein Films and Composites for Biodegradable Food Packaging, Int J. Food Sci. Technol. 30:599–608 (1995).
Tatham, A.S., J.M. Field, V. Morris, K.J. L'Anson, L. Cardle, M.J. Dufton, and P.R. Shewry, Solution Conformational Analysis of the α-Zein Proteins of Maize, J. Biol. Chem. 268: 26253–26259 (1993).
Matsushima, N., G. Danno, and Y. Izumi, Preliminary Small-Angle X-ray Scattering Study from Maize Zein Proteins, Rep. Prog. Poly. Phys. Japan. 37:631–632 (1994).
Matsushima, N., G. Danno, H. Takezawa, and Y. Izumi, Three-Dimensional Structure of Maize α-Zein Proteins Studied by Small-Angle X-ray Scattering, Biochim. Biophys. Acta 1339: 14–22 (1997).
Swallen, L.C., Zein—A New Industrial Protein, Ind. Eng. Chem. 33:394–398 (1941).
Bernardi, D.J., Method of Drying Ink, U.S. Patent 2,285,183 (1940).
Kroeger, J.W., and H.F. O'Connor, Printing Ink Containing Zein, U.S. Patent 2,366,970 (1941).
Katayama, H., H. Ishida, H. Yoshimoto, and M. Kanke, Evaluation of Zein Tablets for Sustained-Release Dosage from in vitro and in vivo, Drug Delivery Syst. 12:19–25 (1997).
Aydt, T.P., C.L. Weller, and R.F. Testin, Mechanical and Barrier Properties of Edible Corn and Wheat Protein Films, ASAE 34:207–211 (1991).
Yamada, K., A. Noguchi, and H. Takahashi, Effects of the Solvents on Properties of Zein, Nippon Shokuhin Kagaku Kogakukaishi 43:306–312 (1996).
Lai, H.M., G.W. Padua, and S. Wei, Properties and Microstructure of Zein Sheets Plasticized with Palmitic and Stearic Acids, Cereal Chem. 74:83–90 (1997).
Lai, H.M., and G.W. Padua, Properties and Microstructure of Plasticized Zein Films, ——Ibid. 74:771–775 (1997).
Lai, H.M., and G.W. Padua, Water Vapor Barrier Properties of Zein Films Plasticized with Oleic Acid, ——Ibid. 75:194–199 (1998).
Shewry, P.R., M.J. Miles, N.H. Thomson, and A.S. Tatham, Scanning Probe Microscopes—Applications in Cereal Science, ——Ibid. 74:193–199 (1997).
About this article
Cite this article
Yoshino, T., Isobe, S. & Maekawa, T. Physical evaluation of pure zein films by atomic force microscopy and thermal mechanical analysis. J Amer Oil Chem Soc 77, 699–704 (2000). https://doi.org/10.1007/s11746-000-0112-7
- Atomic force microscopy (AFM)
- biodegradable film
- contact angle
- thermal mechanical analysis
- zein film