Background and Objectives: Application of biopolymers-based films because of disadvantages such as poor mechanical and barreir properties han been limited in the packaging. One of the solutions to overcome this problem is production of nanocomposites. In this way, inorganic and organic fillers can be used. The aim of this study was to compare the effect of organic celloluse nanocrystal (CNC) and inorganic nanoclay (NC) on the properties of the whey protein isolate (WPI) film.

Materials & Methods: CNC and NC (sepiolite) were extracted from oat husk and mines in Yazd, respectively, and incorporated to the WPI film forming blend in various loading contenets (2, 4 and 6 wt%). Then their effect on mechanical properties, water vapor permeability (WVP), solubility and transparency of the films was investigated.

Results: Both of these nano-particles decreased the WVP of the films, but in this case, CNC showed better performance. The CNC increased solubility in water of the fimls due to the hydrophilic nature, but addition of NC decreased solubility in water due to disc structure. The tensile strength (TS) and modulus of elasticity (E) of the nanocomposite films containing CNC increased. However, NC had no significant effect on TS, and only in concentration of 4% increased significantly on E. Elongation at break and transpareny of films were decreased by both of CNC and NC.

Conclusion: Organic CNC, in addition to its ability to make a fully renewable and natural nanocomposites, may also improve the mecanical and barreir properties of protein-based polymers compared to inorganic NC fillers.