14B-1 |
Detection properties of gamma-irradiated corn starch and Panicum miliaceum and their quality changes during storage following re-irradiation |
H. K. KIM1, M. G. Choi1, C. Choi2, Y. Jeong3, and J. H. Kwon4. (1) Dept. of Food Chemistry & Biotechnology, Korea Food Research Institute, San 46-1, Baekhyun-Dong, Bundang-Ku, Songnam, Kyonggi-Do, 463-420, South Korea, (2) Dept. of Food Science & Technology, Yeungnam Univ., 214-1 Dae-Dong, Kyungsan, Kyungbook, 712-749, South Korea, (3) Dept. of Food Science & Nutrition, Dankook Univ., San 8 Hannam-Dong, Yongsan-Ku, Seoul, 140-714, South Korea, (4) Dept. of Food Science & Technology, Kyungpook National Univ., 1370 Sankyuk-Dong, Buk-Gu, Daegu, 702-701, South Korea Food irradiation is increasingly used as one of the processing methods for reducing spoilage and extending the shelf-life of foods in many countries. As the use of irradiation increases and new application for its use are developed, there is also increased interest in detection methods for monitoring the presence of irradiated items in the food supply.The objectives of this study were to investigate the detection properties of gamma-irradiated corn starch and Panicum miliaceuma grown in Korea and China and their quality changes during storage following re-irradation. Corn starch and Panicum miliaceum were purchased dried from the market and ground to the size of 500µm. Samples were irradiated at dose level of 5kGy using a Co60 irradiator. And then the samples were re-irradiated after 6 months and 12 months during the storage at 0 °C. Starch contents and viscosity of the samples were measured by the methods of Somogyi and Hayashi, respectively. Specific parameter values were calculated by the formula of Hayashi and used to determine if the samples are irradiated. TBA values were determined by the method of Turner and color of samples was measured by color difference meter. Irradiated samples showed a decrease in viscosity after irradiation and re-irradiation. The samples of non-irradiated, irradiated and re-irradiated could be distinguished by the difference in viscosity. Specific parameter values resulted in dose-dependent relationship between non-irradiated and irradiated samples where all values of the re-irradiated were lowest. TBA values were increased with the irradiation dosage and storage period. Hunter's L and b values were decreased with dose level increased while the a values were increased. These values were not affected with the elapes of the storage period thereby resulting in overall color difference(DE) in a minor change. These results suggest that the irradiated and re-irradiated corn starch and Panicum miliaceum can be detected by viscometric methods. Moreover, the method could detect irradiation and re-irradiation of the samples even after 12 months during storage.
Session 14B, Food Chemistry: Physicochemical properties
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