The use of macroalgae has been always linked to direct consumption, however, current trends have increased the applications of algae in the formulation of foods to replace animal proteins. Hence, we must ensure the safety of the increasing food products based on macroalgae. In this regard, and due to the worldwide variability of its composition, we determined the nutritional characterization of Durvillaea Antarctica, Macrocystis pyrifera, and Lessonia nigrescens to evaluate their potential at nutritional level. Also, as they are accumulating organisms, we characterized their minerals and heavy metals content, to determine its potential applications and consumption risks. The results indicated that the content total As is into the safe range to be consumed (16.92 and 60.75 mg/kg dw), but Cd (between 3.97 and 6.15 mg/kg dw) is higher than 0.5 mg/kg of final product (regarding Chilean Normative), and in this case, we have two possibilities: To add no more than 12.5% of M. pyrifera and no more than 8% of D. antarctica or L. nigrescens flour in the final product; or avoid the heavy metals by the extraction of alginates to enhance applications in food such as increasing the viscosity or improving dispersion stability. From the last point of view, we have compared the alginates extracted from D. antarctica, M. pyrifera, and L. nigrescens through the use of two methodologies to obtain calcium alginate (10.55-16.75% extraction yield) and sodium alginate (12.45-20.8% extraction yield), where the methodology to extract sodium alginate showed the best perform for the three macroalgae. The results showed that viscosities at 20 degrees C and alginate concentration of 40 g/L were: 1201.4 cP, 544.0 cP and 722.4 cP for D. antarctica, M. pyrifera, and L. nigrescens respectively. With these results we can conclude that the macroalgae D. antarctica is the one with both the highest extraction yield and technological potential as it generates a higher viscosity.