Alginate Capsules: Versatile Applications and Production Techniques

Alginate is a natural polysaccharide commonly obtained from brown algae and is usually used in the food industry as an additive, specifically as a thickening, gelling, and emulsifying agent. Due to its polyanionic nature, it can crosslink in the presence of divalent or trivalent cations. This crosslinking process involves the formation of chemical bonds between the carboxylic groups of parallel chains, resulting in a solid structure. In this way, compounds of interest can be enclosed in a capsule or a bead. Thanks to this ability, possible applications of alginate capsules are countless: it is possible to range from the pharmaceutical to the nutritional fields, from the agri-food industry to the textile or cosmetic sectors. These capsules can protect the encapsulated ingredients, promote their delivery or controlled release, or be imagined as small-scale reactors. The present review describes the main techniques used to produce alginate capsules, and several examples of possible application fields are shown.