Preparation and characterisation of zein films obtained by electrospraying

• Published in: Food hydrocolloids 2015-07, Vol.49, p.1-10
• Main Authors: Gaona-Sánchez, V.A., Calderón-Domínguez, G., Morales-Sánchez, E., Chanona-Pérez, J.J., Velázquez-de la Cruz, G., Méndez-Méndez, J.V., Terrés-Rojas, E., Farrera-Rebollo, R.R.
• Format: Article
• Language: English
• Subjects: Casting; Electrospraying; Zein films
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/j.foodhyd.2015.03.003

Electrospraying is a technique now applied for the production of food nanoparticles, nanofibres and nanocapsules, which could constitute a good alternative for the development of films. The goal of this work was to determine the electrospraying operation conditions and the zein concentration that would allow a film to be produced and also to evaluate the structural characteristics and barrier and thermal properties of films developed at different thicknesses. Results showed that films can be obtained by electrospraying, resulting possible to produce homogeneous films, without electrical arc formation during processing when using a 11.4% zein solution, an electrical voltage of 7.8–8.7 kV and a distance of 1.5 ± 0.5 cm between the nozzle and the deposit plaque. Regarding the effect of the production methods (electrospraying and casting) and the film thickness on film appearance, both variables had significant effect on colour parameters, observing a more yellowish colour (b* = 72.3 ± 6.8) and lower transparency (%T = 90.6 ± 0.21) at larger thicknesses (100 μm), and a smoother and more homogeneous surface (ESEM) when films were obtained by electrospraying. Water vapour permeability was only influenced by film thickness (1.51 × 10−08 to 3.11 × 10−08 g/s-m-Pa) in both methodologies. The glass transition temperatures (Tg) for electrospraying and casting films were different (222 °C and 231 °C respectively) and higher than that of zein powder (165 °C), indicating a possible change in the film structure due to the process. Under the process conditions tested in this work, electrospraying can be considered as an alternative technique to produce films. [Display omitted] •Electrospraying can be used to produce zein films.•Electrospraying generates similar films to those produce by casting.•Electrosprayied zein generates different products as varying process conditions.