Effects of lutein particle size in embedding emulsions on encapsulation efficiency, storage stability, and dissolution rate of microencapsules through spray drying

Microencapsulation is an effective technique for maintaining stability of labile bioactive components. However, as an indispensable process prior to microencapsulation, the effects of emulsion preparation on micro-encapsulated products are often overlooked. In this study, three industrialized comminution techniques (wet media milling, high pressure homogenization, and colloid milling method) were used to manufacture four lutein-loaded primary emulsions with different lutein particle size (from 238.2 nm to 2.2 mu m). Subsequently, lutein-loaded emulsions were microencapsulated through spray drying. The physicochemical properties, encapsulation efficiency, storage stability, and dissolution rate of lutein microencapsulated powder (LMPs) were examined to evaluate the effects of different emulsions on the quality of LMPs. Results indicated that the encapsulation efficiency and storage stability of LMPs decreased as the lutein particle size in emulsions increased. The LMP with smallest lutein particles possessed highest encapsulation efficiency (97.9%) and storage stability (plateau value of 89.44 and 78.85% at 25 degrees C and 40 degrees C). In vitro release study showed that apparent solubility and dissolution rate of LMPs containing nano-sized particle were significantly increased, compared with micron-sized LMPs and physical mixture. Our study suggested that preparing the emulsion containing nano-size lutein particles is critical for improving shelf life and oral bioavailability of this bioactive product.