3.2.3. Agar Use for Probiotic Delivery

Agar is one of the polysaccharides intensively used to obtain tablets or other formulas of drugs released in the gastrointestinal tract, but is less used as an encapsulating agent for probiotics. Although there have been attempts to microencapsulate with agar, when used in

combination with other biopolymers (Table 6), research on its use is limited. This is due to the higher ability to obtain films and lesser ability to facilitate the development of coatings. These applications are mainly due to the ability of agar to form viscous solutions by solubilizing the powder in water at very high temperatures (over 90 ◦C) in order to obtain a termoreversible gel. Agar cannot produce gel at lower temperatures and high temperatures affect the viability of microorganisms. To date, no working method that could involve the solubilization of agar powder in liquids with lower temperatures has been developed. When used as an encapsulating material for essential oils, the temperature of the filmforming solution is lowered to 40 ◦C, after which essential oils are incorporated [216,217]. Agar-based films have low mechanical properties such as low tensile strength and poor elasticity. Therefore, in the development of films, it is preferred to mix it with other polysaccharides, proteins, or lipids.
