Rye secalin characterisation and use to improve zein-based film performance

Rye prolamins (secalin) were extracted, characterised and used as biopolymer source to produce plasticised films, as well as composite films in the presence of corn zein. Secalin film showed lower contact angle values and higher moisture content, solubility and swelling index than zein film, whereas the water vapour permeability of the two films was not different. Also, secalin film exhibited lower tensile strength and Young’s modulus and higher elongation at break. The average functional properties of the secalin/zein blend were morphologically confirmed by SEM analysis of the composite film surface that showed a good miscibility and compatibility of the two different biopolymers. These results indicated that secalin films were less hydrophobic and more flexible than those previously prepared by using other prolamins, whereas a material with hydrophobic features similar to those of zein films and a flexibility comparable to that exhibited by secalin films was obtained by preparing a secalin/zein blend.