الفهرس | Only 14 pages are availabe for public view |
Abstract Interest in biodegradable materials for packaging and agricultural uses has grown in recent years. Plant proteins have been proposed as inexpensive, renewable, and abundant feedstock. Zein was investigated based on value-added considerations and on the unique thermoplastic and hydrophobic properties of it. Films prepared from zein are known to be hard and brittle, thus requiring the addition of plasticizers to improve flexibility. Cross-linked and chemical modified zein films as an alternative to packaging films consisting of non-degradable polymers were prepared to evaluate mechanical, thermal, contact angle, surface morphology and color properties of the resulting film, as affected by formulation process (cross-linker type, cross-linker concentration and type of aldehydes used in chemical modification). Zein films were obtained through a simple solvent casting method. Zein with concentration 8% was dissolved in 88 % aqueous ethanol solution at room temperature for cross-linking process. In chemical modification process, 10% zein was used at different times and temperatures. The resulting zein films showed good appearance and flexibility. The prepared films showed improvement in mechanical properties when using eugenol & citric acid and eugenol & succinic acid as a cross-linker. On the other hand in case of chemical modification the prepared films showed very good improvement in elongation properties for the films. The prepared films showed antimicrobial effect towards pathogenic strains (seven strains) depending on type of cross-linkers compound used or type of aldehyde used in chemical modification. Finally addition of bacteriocin like nisin improves antimicrobial effect of films towards specific strains. |