A detailed microstructural and multiple responses analysis through blocking design to produce Ca(II)-alginate beads loaded with bioactive compounds extracted from by-products

•Co-joint RSM-optimization and microstructural study for alginate beads is presented.•The use of blocking design was effective as a classification criterion.•The inclusion of extracts promotes changes in microstructure of the Ca(II)-alginate.•The variation of alginate concentration induces main microstructural changes.•The optimized condition is consistent with the microstructural stability.