Improvement of the water resistance and ductility of gelatin film by zein

Gelatin films do not have sufficient water resistance to withstand high moist when used as food packaging. In this study, the water resistance property of gelatin film was firstly improved by compositing with hydrophobic zein for moist food packaging application. Zein was processed with gelatin at different ratio to form composite films. The solubility of the composite films in water decreased to 40% and the reduction of affinity to water was affirmed by higher water contact angle. The crystallinity percentage of the films were increased, detected by the x-ray diffraction (XRD), which might be also contributed in the water resistance. The modification in secondary structure of gelatin/zein was observed by FTIR spectroscopy. Moreover, zein also could improve the ductility of gelatin films in the presence of plasticizer. Elongation, a measure of ductility, of the films improved with up to 87%. Zein dispersed into gelatin homogeneously till 20% and higher concentrations result in large aggregates of zein molecules that lead to weakened molecular interaction. The aggregation of zein was observed by SEM to confirmed the desirable gelatin/zein ratio.