Elemental composition analysis in Sangyod rice by instrumental neutron activation analysis

Sangyod Muang Phatthalung Rice is a traditional rice variety grown in the area of Phatthalung province for more than a hundred years. Sangyod rice is the first rice variety of Thailand that has been registered as Geographical Indication (GI). It is also good rice for anyone who is searching for good health. The concentrations of nine elements (Mg, Al, Cl, As, Br, K, Mn, Rb and Zn) in Sangyod rice, locally cultivated in four districts (Pak Phayun, Tamot, Pa Phayom and Muang) in Phatthalung province, were determined using instrumental neutron activation analysis (INAA). The method validation of INAA was verified by SRM 1568a Rice Flour. All elements were found to be in a good agreement with the certified values. The results were analyzed using analysis of variance and Tukey's HSD test. There were no statistical differences in concentrations of Mg, Al, As, Br, K and Mn in rice from four districts. The concentrations of Cl, Rb and Zn found in rice were significantly different according to the cultivation region. Therefore, Cl, Rb and Zn were good characteristic indicators for Sangyod rice that could be applied to identify the geographical origins of rice.