A phenomenological and thermodynamic study of the water permeation process in corn starch/MMT films

• Published in: Carbohydrate polymers Vol. 90; no. 1; pp. 551 - 557
• Main Authors: Slavutsky, Aníbal M., Bertuzzi, María A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-09-2012; Elsevier
• Subjects: Applied sciences; Bentonite - chemistry; Bentonite - metabolism; Composites; corn starch; diffusivity; edible films; Exact sciences and technology; Forms of application and semi-finished materials; nanoclays; Permeability; Polymer industry, paints, wood; sorption; Sorption isotherms; starch; Starch - chemistry; Starch - metabolism; Starch/MMT film; Technology of polymers; temperature; Thermodynamic parameters; Thermodynamics; Water - chemistry; Water - metabolism; water activity; X-Ray Diffraction - methods; Zea mays; Thermodynamic parameters; Permeability; Starch/MMT film; Sorption isotherms; Clay; Transport properties; Montmorillonite; Glycerol; Experimental study; Corn starch; Steam permeability; Plasticizer; Moisture regain; Oside polymer; Nanocomposite
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2012.05.077

► Formulation and characterization of starch/MMT films. ► MMT addition improves barrier properties and water resistance of films at middle and lower water activity range. ► Thermodynamic analysis of water sorption process of film matrix. ► Phenomenological description of permeation process and study of the effect of driving force on phenomenological coefficient.
Water transport in edible films of starch based products is a complex phenomenon due to the strong interaction of sorbed water molecules with the polymeric structure of starch. Moisture sorption isotherms of starch and starch/MMT films were obtained. The results indicated that nanoclay incorporation produces a decrease of water uptake at all temperatures analysed. Thermodynamic parameters showed that sorption process is less favourable when MMT is incorporated into the starch matrix. Effect of driving force and water activity (aw) values at each side of the film on permeability and diffusivity coefficients were analysed. The effect of the tortuous pathway generated by MMT incorporation was significant only in the middle and lower range of aw. At high aw range the plasticizing effect of water dominated and MMT incorporation had little effect on the water barrier properties of these films.