CHIA TRACE ELEMENTS DETECTION BY NEUTRON ACTIVATION ANALYSIS

Chia seed is an ancient grain that is becoming popular in modern food regimen for their nutritional value and functional properties, although many tables of food composition do not provide complete information about it. Trace and ultra-trace elements are indispensable for human health as they are involved in biochemistry regulations, such as transport and oxygen activation, electron transport, catalytic center in oxide reduction processes, catalytic center in acid-base processes and structural function. For both diet assessment and prescription, reference values for trace elements as recommended daily intake, recommended dietary allowance and tolerable upper intake level were established. Instrumental neutron activation analysis (INAA) is a noble method to identify and quantify trace and ultra-trace elements that has high sensitivity for many elements, has little or no sample contamination, resulting in low blank values, has virtually no matrix effects and multi element capability. The aim of the present work was to identify and quantify by INAA mineral elements of chia seeds. Two subsamples of chia flour and standard reference samples where irradiated on the research nuclear reactor (IEA-R1) of IPEN by neutron flux of 9 x 1011n cm-2 s-1, for 30 sec for analysis of Ba, Cl, Cu Mg, Mn, Ti and V. For analysis of As, Br, Ca, Cr, Co, Fe, K, La, Mo, Na, Rb, Sb, Sc, Se and Zn three subsamples of chia flour and standard reference samples where irradiated for 8 h, by neutron flux of 0,97 x 1012 n cm-2 s-1. The results showed higher content of Ca, K, Zn and Fe when compared with data from the literature obtained by other analytical methods. Besides that, using INAA was possible to detect elements that was not commonly verified with others measuring methods.