Mechanical and optical evaluation of alginate hydrospheres produced with different cross-linking salts for industrial application

Alginate spheres complexed with various divalent cations and various counterions associated with calcium were characterized mechanically and optically. Zinc exhibited the most intense absorbance increase from the visible to ultraviolet wavelength range, a desirable characteristic for use in sunscreens. Among the calcium salts, only chloride and lactate exhibited the same behavior, although with a lower intensity. The values of the Young’s moduli of alginate spheres produced with zinc and lead were similar to the highest values that have been reported thus far, for cadmium and copper. Spheres produced with calcium gluconate were also among the stiffest. The mass of the beads decreased when they reacted with most of the saline solutions used, except in the case of calcium chloride and calcium lactate. Cations having high atomic numbers produced stiffer alginate spheres, due to the interaction mechanisms involved in polysaccharide reticulation. The present analyses are important for the development of new products and processes for the pharmaceutical, food, environmental, and biotechnological industries.