The enhanced stability of β-carotene by encapsulation into hollow mesoporous silica nanoparticles

Abstract

Carotenoids are widely-distributed botanical pigments which are closely involved in photosynthesis and present multiple bioactivities in human health. β-carotene (β-car) is one of the most extensively investigated carotenoids because of its provitamin A activity and many biological activities. However, its instability and highly hydrophobicity limit its applications in food processing and decrease its bioavailability. Although many efforts had been made by encapsulating β-car into different materials to solve these problems, these systems cannot satisfy the requirements to the varied and complex application of β-car in food and medicine field. Therefore, development of alternative new carriers may provide diversified carrier systems for β-car that best fit the practical usage of β-car in different processing operations. Considering the widely-accepted advantages of hollow mesoporous silica nanoparticles (HMSN) in the drug delivery system research, this study aimed to encapsulate β-car into HMSN in order to improve its instability and poor aqueous dispersibility. HMSN with average particle size about 230 nm was successfully prepared. The BET surface area, pore volume, and average pore size were calculated as 423.3 m 2 /g, 0.456 cm 3 /g and 3.95 nm, respectively. β-car was encapsulated into HMSN via solvent impregnation method to form a nanocomposites (HMSN@β-car) which could be well dispersed in water. The drug loading rate was calculated as 17.5%. And then, the stability of β-car in HMSN@β-car and its free forms against temperature, pH and light irradiation was compared. The results showed that encapsulation of β-car in HMSN enhanced its stability against temperature, pH and light irradiation. Besides, DPPH and ABTS assays showed that HMSN@β-car reduced the loss of antioxidant activity caused by temperature. In conclusion, encapsulation of β-car into HMSN could enhance its stability, decrease the loss of its antioxidant activity, and improve its aqueous dispersivity. Our results indicated that HMSN could serve as a candidate system for β-car carrier when we choose the system that best fit the practical usage of β-car in different processing operations.