Elemental imaging by Laser-Induced Breakdown Spectroscopy to evaluate selenium enrichment effects in edible mushrooms

Mushrooms are bioaccumulating organisms commonly used in selenium (Se) enrichment studies. However, the addition of Se in the culture medium may alter the distribution of other essential elements in the mushroom fruiting body. To evaluate the effects of the Se enrichment, Ca, Mg, and K distributions in pink oyster (Pleurotus djamor) and K and Mg distributions in white oyster (Pleurotus ostreatus) mushrooms were mapped by laser-induced breakdown spectroscopy (LIBS), which can be used at room temperature and requires minimal or no sample preparation. It was verified that Se enrichment favoured the accumulation of Ca in the lower part of the pink oyster mushroom and prevented the transport of this element to the edges and tops. The Se enrichment also altered the distribution of K and Mg, decreasing the numerical correlation between the K and Mg distributions (R-2 = 0.5871). In the white oyster mushroom, however, despite the changes in the morphological characteristics of the fruiting bodies after enrichment, there were generally nonsignificant differences in the K and Mg distributions between the control and the Se-enriched mushrooms. (AU)