Characteristics of bio-nanocomposite films from tilapia skin gelatin incorporated with hydrophilic and hydrophobic nanoclays

Properties of films from tilapia skin gelatin incorporated with hydrophilic and hydrophobic montmorillonite (MMT) nanoclays at various levels (0-10%, w/w) were investigated. Generally, mechanical properties were improved by the addition of hydrophilic nanoclay (i.e., Cloisite Na+) in the range of 0.5-5% (w/w). The lowest water vapour permeability was observed for films incorporated with Cloisite Na+ and Cloisite 20A at a level of 1% (w/w) (P < 0.05). The lowest L* and the highest Delta E* values were observed (P < 0.05) when the film was incorporated with Cloisite 15A at 10% (w/w). Generally, b* value (yellowness) of resulting films increased with increasing amount of all nanoclays (P < 0.05). All films became less transparent with increasing levels of nanoclay incorporated (P < 0.05). Wide angle X-ray diffraction and scanning electron microscopic analyses revealed the intercalated/exfoliated structure of nanocomposite gelatin-based films incorporated with hydrophilic and hydrophobic nanoclays. Homogeneity and smoothness of film surface decreased with the addition of both nanoclays as revealed by SEM micrographs. Thermogravimetric and differential scanning calorimetric analyses indicated that the incorporation of nanoclays enhanced the rigidity and heat stability of the gelatin-based films differently, depending on the types of MMT-nanoclay used. Thus, the types and levels of nanoclay incorporated directly affected the properties of tilapia skin gelatin films. (C) 2014 Elsevier Ltd. All rights reserved.