45D-10

Recently, the interest of incorporation of natural constituents in foods system is increased. Edible and biodegradable film packaging is an example of such incorporation. The formulations of these films have been modified extensively, in order to have to physical and mechanical properties that meet the food packaging requirements.

The objective of this research was to determine the physical and mechanical properties of high-amylose rice and pea starches edible films so as to determine their potential applications.

3% aqueous solution of pea starch or rice starch was prepared and glycerol, as plastisizer, was added at a ratio of 1:2 (w/w) glycerol: starch. The solution was mixed properly in cold water and heated with continuous mixing until boiling and left boiling for 15 minutes for complete swelling of starch granules and gel formation. It was left to be cooled to ~60 °C and then casted into plates and left to be dried before being peeled off.

Compared to most commonly used edible and non-edible films (whey protein, soy protein, corn zein and wheat gluten), high-amylose rice and pea starches films had 2-26 times higher percentage of elongation and 4-173 times lower oxygen permeability. Their water vapor permeability values were 2.5-40 times higher than that of protein based films and their solubility and tensile strength were comparable to other films. In compliance to the most water soluble films, the oxygen permeability of high-amylose rice starch and pea starch films increased with increasing relative humidity up to 45% and they showed an excellent oxygen barrier at relative humidity below 40 %.

The low cost, ease of preparation, non-allergenicity and the superior mechanical properties of these films, potentiate their wider applications where high elongation, intermediate water vapor permeability and excellent oxygen barrier are required such as oxidative intermediate-moisture or dried foods.