Application of ED-XRF Spectra for Determination of Macroelements in Edible Seaweeds

The application of an increased number of edible seaweeds in gastronomy requires accurate, rapid, and non-destructive mineral evaluation. In this work, energy dispersive X-ray fluorescence (ED-XRF) spectra were used to determine Ca, K, and P in edible green, red, and brown seaweeds from the Portuguese coasts. ED-XRF raw spectra of seaweed samples were correlated against results of conventional inductively coupled plasma-optical emission spectrometry (ICP-OES), by the full cross-validation partial least-square (CVPLS) regression method, with nonlinear iterative partial least squares (NIPALS) algorithm. The standard reference material (Thallus laminariae) was used for the validation of CVPLS. Statistical parameters, correlation coefficients (R2), root mean square errors (RMSE), and bias, were used for the assessment of the CVPLS method. For selected minerals, R2 was high (0.88–0.95), while RMSE values (< 1.02) and bias (0) were low, thus indicating a viable potential for their routine analysis by ED-XRF. These findings highlighted the quality of ED-XRF spectral data, which can be used for an efficient non-destructive determination of macroelements in edible seaweeds on a large food industrial scale.