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The influence of the amylose:amylopectin ratio on the properties of pea, potato and 30 cassava starch (with a high, intermediate and low amylose-amylopectin ratio, 31 respectively) films and the effect of the incorporation of rice bran of two different 32 particle sizes were studied. The structural, mechanical (elastic modulus, tensile 33 strength and percentage of elongation at break), optical (gloss and internal 34 transmittance) and barrier (water vapour permeability and oxygen permeability) 35properties of the films were analysed after 1 and 5 weeks under controlled storage 36 conditions (25ºC and 53%RH). The properties of the films were affected by both 37 amylose-amylopectin ratio and storage time. The high content of amylose gave rise to 38 stiffer, more resistant to fracture, but less stretchable films, with lower oxygen 39 permeability and greater water binding capacity. Although no changes in the water 40vapour permeability values of the films were observed during storage, their oxygen 41 permeability decreased. Throughout storage, films became stiffer, more resistant to 42 break, but less stretchable. Rice bran with the smallest particles improved the elastic 43 modulus of the films, especially in high amylose content films, but reduced the film 44 stretchability and its barrier properties, due to the enhancement of the water binding 45 capacity and the introduction of discontinuities (fibre particles) in the matrix. 46 47

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Cassava starch films containing 25 and 50 % (in the polymer blend) of bovine gelatin were obtained using glycerol (30 %) as plasticizer. Film formulations were also obtained with 15 % of lipid (blend of fatty acid-glycerol esters). Microstructural and physical (optical, barrier and mechanical) properties were analysed in order to compare blend films with neat starch or gelatin films. The incorporation of gelatin and lipids to glycerol-plasticized cassava starch films notably affected their physical properties, while they showed polymer-phase separation and a lipid-dispersed phase. Gelatine incorporation gave rise to harder films with greater resistance to break and extensibility, while the lipids decreased film hardness and resistance but enhanced the stretchability, especially in films with 50 % gelatin content. Likewise, lipids improved water barrier properties of the films, but they impaired the oxygen permeability at the same time as they decreased the film gloss and transparency. After 5 weeks of storage, all the films became harder and more resistant to break, especially those which did not contain lipids, which enhanced the films' extensibility during storage. Cassava starch films with 50 % gelatine, both with and without lipids, exhibited very adequate properties for food coating or packaging.

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The effect of surfactant addition on structural, mechanical, optical and barrier properties of