Characterization of rice starch-ι-carrageenan biodegradable edible film. Effect of stearic acid on the film properties

Composite edible films and coatings from food-grade biopolymers

The development of edible films and coatings from food-grade biopolymers has advanced significantly during the past decade. The current state-of-the-art lies in the formulation of composite edible films and coatings from such biomolecules. Composite films and coatings refer to systems where multiple biopolymers have been combined to achieve beneficial properties. Carbohydrate, protein, and lipids have been preferred for developing such systems. Binary films and coatings have been prepared from multiple combinations including protein-protein, carbohydrate-carbohydrate and protein-carbohydrate. Similarly, ternary films and coatings have been prepared from protein-protein-carbohydrate combinations. In addition, several active ingredients including antimicrobial compounds have been loaded to these systems for the preparation of functional films and coatings. Therefore, the goal of this manuscript is to review the multitude of composite systems that are currently available for food packaging purposes. In addition, we discuss the application of composite coatings to fruits and vegetables, dairy, meat and seafood as model food systems.

Physical and mechanical properties of a new edible film made of pea starch and guar gum as affected by glycols, sugars and polyols

The influence of different plasticizers (glycols, sugars and polyols) on the moisture sorption, mechanical, physical, optical, and microstructure characteristics of pea starch-guar gum (PSGG) film was studied. All plasticizers formed homogeneous, transparent, and smooth films, while PEG-400 did not produce film with suitable characteristics. Fourier transform infrared (FTIR) spectroscopy results indicated some interaction between plasticizers and the polymers. Scanning electron microscopy (SEM) observations of the films presented surfaces without cracks, breaks, or openings which were indicator of the miscibility and compatibility of employed plasticizers with PSGG films. The results showed that the films containing plasticizers with higher functional groups had lower equilibrium moisture content at aw <0.4. In general, a reduction in tensile strength and Young's modulus and an increase in elongation at break were detected when molecular weight of plasticizers and relative humidity increased in all film formulations. Films plasticized with monosaccharide showed similar mechanical properties to those with sorbitol, but lower solubility and water vapour permeability (WVP), higher transparency and moisture content than the sorbitol-plasticized films. The most noticeable plasticization effect was exerted by following order: glycerol > EG > PG > xylitol > fructose > sorbitol > mannitol > galactose > glucose > sucrose > maltitol.