Abstract
Abstract Food irradiation can eliminate microbes, pathogens, or extend the ripening and restrain germination of fruits and vegetables. In Taiwan, food irradiation has been developed and used in daily life. However, it has unestablished a way to detect the foodstuff whether been irradiated. Black pepper irradiated with Co-60 in different doses that would produced free radical in concentration. This signal can be detected by the Electron paramagnetic resonance (EPR) spectroscopy. EPR spectroscopy measures the unpaired electrons of free radicals, and EPR signal is derived from the conversion of electron spin resonance absorption. The stronger EPR signal, the higher concentration of free radicals. The intensity of EPR signal is proportional to radiation dose. This study proved that the EPR signal strength would decrease with storage time increasing. Besides, the peak-to-peak high and peak-to-peak high ratio of the irradiated black pepper are stronger than the non-irradiated ones. Finally, the study proposes two discriminator values. One is identified by the peak-to-peak high, and the other is identified by the ratio of peak-to-peak high. If peak-to-peak high or the ratio of peak-to-peak high exceeds the discriminator value, black pepper was processed by radiation irradiation. This study demonstrates the relationship of the EPR signal between radiation dose and storage time from the results, and has preliminarily developed a method to tell non-irradiated and irradiated food apart. This method desires to filter the irradiated food and enhances food safety and sanitation. Key Word：Food irradiation、Electron paramagnetic resonance、peak-to-peak high、peak-to-peak high ratio.