Development and characterization of some composite (WPI, SPI and CMC based) edible films

Edible films based on different proteins, polysaccharides and/or lipid were developed with their optimal proportions. Whey protein isolate (WPI), soy protein isolate (SPI) and carboxymethyl cellulose (CMC) were used as protein and polysaccharide resources, respectively. Besides, sunflower oil (SO) was added into the films. Moisture absorption, mechanical, barrier, physical and thermal properties of the composite films were investigated. Moisture absorption of the films containing single component was tested at three different relative humidity (30, 50 and 80%) conditions at room temperature using dynamic vapor sorption instrument. Water vapor permeability (WVP) and oxygen permeability (OP) of the films were determined using analytical and instrumental techniques, respectively. Significant reduction in WVP and OP of the WPI films was obtained upon addition of SO. Mechanical properties also affected by addition of SO that percent elongation (%E) was increased by four times. It was determined that glass transition temperature was increased proportionally with SO amount for WPI films but SPI-SO blend film had less value than that of SPI. CMC addition improved the WVP but it caused negative effect on OP. WS1 (0.05% SO added WPI) and SPI-CMC were assumed to be the best two combinations among all studied films. Key words: Composite edible film, whey protein isolate, soy protein isolate, carboxymethyl cellulose, sunflower oil