67C-2 |
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K. B. SONG1, S. Lee2, and M. Lee2. (1) Dept. of Food Science & Technology, Chungnam National Univ., College of Agriculture & Life Sciences, 220 Gung-dong, Yuseong-gu, Daejon, 305-764, South Korea, (2) Chungnam National University Protein films offer environmental compatibility as well as higher quality and longer shelf life of foods. Protein films are good oxygen and carbon dioxide barriers, yet inferior water vapor permeability compared to plastic films. To improve functional properties of protein films, cross-linking agents or ionizing radiation have been tried. Our objectives were to elucidate the effect of g-irradiation on the physicochemical properties of zein films and to improve the water vapor permeability and color of the films. Zein film forming solutions were prepared by heating and stirring a mixture of 10% corn zein, 2% glycerol, and 0.2% soy bean oil in 100ml of 95% ethanol and then irradiated at 0, 4, 16, 32, and 50 kGy using a 60Co gamma irradiator. Film forming solutions were cast and dried films were peeled intact from the casting surface. Film tensile strength and elongation at break were determined. Water vapor permeability and color values of the zein films were determined. Scanning electron microscopy was used to characterize the microstructure of zein film. Gamma-irradiation of zein solutions caused the disruption of the zein molecules based on a SDS-PAGE study. Alteration of zein molecules by radiation decreased water vapor permeability by 12% and increased elongation of zein films by 80%. However, mean tensile strength of zein films was slightly decreased. Measurement of Hunter color values indicated that radiation caused a destructive effect on yellow color, resulting in a significant decrease in Hunter b values. Microstructure observed by scanning electron microscope showed that irradiated zein film had a smoother and glossy surface than the control film. These results clearly imply that g-irradiation treatment of the zein film forming solutions decreased water vapor permeability as well as yellow color and it can be a useful tool to improve the properties of zein films.
Session 67C, Food Chemistry: Food analysis, irradiation and toxicology
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