Encapsulation and delivery of bioactive compounds using spray and freeze-drying techniques: A review

There are various bioactive components exist in plants, fruits, and vegetable origins that have many beneficial health effects (mainly antioxidant). However, they suffer from low-stability against the environmental condition. Thus, the encapsulation approach emerged to decrease their sensitivity and present a target delivery system. Generally, native carrier agents (polysaccharides and proteins) are being applied to embed the core materials. Accordingly, many encapsulation methods have been developed to protect vulnerable components by these carriers. Spray and freeze-drying are common encapsulation methods with the ability of powder production. Both feed emulsion production and drying process factors substantially influence the core embedded within the carrier agents. Spray-drying is well-known to higher applicable and scalable encapsulation procedure in the food and pharmaceutical industries. It is predominantly related to its lower process costs. Nevertheless, its application is limited for more sensitive bioactive compounds due to hot-air drying exertion. In contrast, freeze-drying has been mostly used for thermo-sensitive ingredients. Its application is restricted by economic drawbacks for which long process time (24-48 h) is required. However, freeze-drying is adequately taken into an advantage in the encapsulation of therapeutic compounds since high-added value products will be produced so that bioactive compounds with higher biological activity are needed.