Manufacturing and analysis of thermal and chemical properties of potato starch - gelatin biofilms

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2012
Yılmaz, Seçil
Today bioplastics, which are defined as environmentally friendly new generation plastics, take place on the market as bags, foam fillers and food tableware. In this study, it was aimed to obtain biodegradable films using starch and gelatin. Thermal, mechanical, permeability and optical properties of films based on potato starch and bovine gelatin plasticized with glycerol and citric acid monohydrate were investigated. Film formulations of different ratios of potato starch to gelatin (1:0, 1:1, 2:1, 1:2, and 0:1) were prepared and casting technique was used as film processing method. In the DSC analysis, one glass transition temperature varying from 69.6 to 91.8ºC for different film formulations was observed, which showed that potato starch and bovine gelatin are compatible. It was determined that blending ratio had an important effect on the mechanical properties. Tensile strength, elongation at break and Young’s modulus was found to be between 2.21-15.60 MPa, 93-130% and 14.20-151.50 MPa, respectively. The findings of this study showed that gelatin addition significantly increased the mechanical durability. The water vapor permeability of films ranged from 0.022x10-10 to 0.061x10-10 g.m-1.s-1.Pa-1 and significantly depended on the blending ratio. It was determined that the films contained gelatin had lower water vapor permeability. It was observed that the blending level has an important effect on the opacity values of films with an opacity-decreasing effect of gelatin. It was also found that storage conditions affected the optical stability. Storage at 40ºC increased the opacity whereas storage at room temperature, +4ºC, and -20ºC had an opposite effect.