| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Tetsuya Faculty of Fisheries, Hokkaido University, 水産学部, 助教授 (60027191)
YASUMOTO Kyoden Research Institute for Food Science, Kyoto University, 食糧科学研究所, 教授 (50026514)
鈴木 富久子 京都大学, 食糧科学研究所, 教務職員 (60183422)
|
|---|
| Research Abstract |
In spite of usefulness of food irradiation in preventing putrefaction of fresh food and in suppressing germination, and for sterilization, there still exist many blockades for its practical use. To make the technology widely acceptable and transferable, attestation of the wholesomeness of irradiated food and establishment of dosimetry of irradiated food are the two wost essential prerequisite.
This research was undertaken to examine if ortho-tyrosine (O-tyrosine), which does not occur in the native protein molecules but was reportedly formed quantitatively in response to irradiation with gamma-ray, could be a marker in chemical dosimetry of irradiated foods. In 1987 fiscal year, efforts were paid to set up the analytical condition for O-tyrosine and to detect qualitative and quantitative changes in food components caused by gamma-ray irradiation. In 1988 fiscal year,hydrolysates of conventional food proteins irradiated at different radiation dose up to 50 kGy was analyzed by high perfor
… More
mance liquid chromatography (HPLC) equipped with electron chemical detector to quantitate O-tyrosine formed by gamma-ray irradiation. However, the occurrence of O-tyrosine under the experimental conditions could not be confirmed from the sample irradiated at any dose level up to 50 kGy by either HPLC or gas chromatography-mass spectrometry. These results suggest that O-tyrosine is hardly produced. or only to a trace amount. if any, by the irradiation within the range of the practical use. Examination of O-tyrosine in the protein which was irradiated at 500 kGy, and extraordinarily high radiation level, has been under way. On the other hand, near infrared spectroscopy (NIR) which was subjected to back up the chemical dosimetry gave quite satisfactory results in the estimation of the radiation dose ranging up to 30 kGy for spices and other food components. This suggests the usefulness of NIR as simple and convenient method in radiation dosimetry of irradiated foods. Evidence was obtained for fragmentation of protein molecule irradiated at 500 kGy. We have not yet been successful in establishing chemical dosimetry for irradiated food by analyzing an anomalous amino acid, O-tyrosine. More efforts should be paid on establishment of chemical and other dosimetries including NIR. Less
|
