The Selective Gas Permeability of the Biodegradable Zein Films

• Published in: Nogyo Shisetsu (Journal of the Society of Agricultural Structures, Japan) Vol. 31; no. 4; pp. 225 - 231
• Main Authors: YOSHINO, Tomoyuki, ISOBE, Seiichiro, MAEKAWA, Takaaki
• Format: Journal Article
• Language: English
• Published: The Society of Agricultural Structures, Japan 2001
• Subjects: biodegradable film; oxygen and carbon dioxide permeability coefficients; selective gas permeability; zein
• ISSN: 0388-8517; 2186-0122
• DOI: 10.11449/sasj1971.31.225

α-zein is a hydrophobic protein of corn. The zein films were cast from an organic solution (70% aqueous acetone or 80% aqueous ethylalcohol) containing zein. Biodegradable zein films without plasticizer were made using various controlled drying conditions during preparation. The zein films were transparent. Oxygen (O2) and carbon dioxide (CO2) permeability of the zein films were measured. The lowest and highest O2 permeability of the zein film was 6.5pmol·m/(s·m2kPa) of the zein ethanol film and 303.3pmol·m/(s·m2kPa) of zein acetone film, respectively. On the other hand, the lowest and highest CO2 permeability of the zein film was 1.0pmol·m/(s·m2kPa) of the zein ethanol film and 1541.0pmol·m/(s·m2kPa) of zein acetone film, respectively. Some zein films have a higher O2 permeability than CO2 permeability. For example, O2 and CO2 permeability of the zein acetone films was 303.3 and 30.6pmol·m/(s·m2kPa), respectively. The ratio of O2 permeability to COT permeability of the 10% zein acetone films increased with increasing relative humidity during drying. The selective gas permeability of the zein films was kept between 5°C and 35°C. By finding relationships between the mechanism of gas permeability and the drying conditions, the film may be formed with advantageous gas permeability properties. We expect that it will be possible to make zein film with various useful gas permeability properties by using controlled drying conditions. The zein films with the selective gas permeability appear to be useful for the agricultural film such as a green house and a mulching.