DEVELOPMENT OF LYOPHILIZED LIPOSOMES COENCAPSULATING VITAMINS D3 AND B12

The use of liposomes in foods has been increasing due to their interesting characteristics, such as low toxicity and possibility of high bioaccessibility and/or bioavailability, as well as compatibility with different bioactives for encapsulation. The objective of coencapsulation in liposomes is to develop formulations rich in different bioactives. Among the liposome production methods, the ultrasonication is a viable and scalable method, and it does not require the use of organic solvents during the process. Due to the known instability of liposome dispersions, lyophilization becomes interesting to ensure long-term stability, extending the integrity and stability of the encapsulated bioactive and reducing the risk of microbiological contamination. In this work, liposomes coencapsulating vitamins D3 and B12 were produced with the saturated/hydrogenated and unsaturated/non-hydrogenated phospholipids (Phospholipon 90G and Lipoid S45, respectively) for future incorporation in yogurts. The phospholipid dispersion was sonicated in an ultrasonic tip homogenizer. After wards, the liposomes were frozen in liquid nitrogen for subsequent drying in a lyophilizer. Sucrose was used as a cryoprotectant in a 2:1 mass ratio (sucrose:phospholipid). The process took place for 48 h, under a vacuum of 444 µHg and a freezing temperature of – 53 ºC. Regarding the physicochemical stability, based on the analysis of the hydrodynamic diameters, the liposomes had a size of 132 ± 8.4 nm and when reconstituted after lyophilization, they had a size of 102 ±1.8 nm. The vesicles encapsulated 47 µg vit D3/ml liposomes and 21 µg vit B12/ml liposomes, and after lyophilization they contained 2.5 µg vit D3/mg liposomes and 1.0 µg vit B12/mg liposomes. On the other hand, the liposomes produced with Phospholipon 90G had a size of 257 ± 6.0 nm and when reconstituted after lyophilization, they had a size of 188 ±3.3 nm, which is larger than the vesicles produced with Lipoid S45. The vesicles encapsulated 47 µg vit D3/ml liposomes and 21 µg vit B12/ml liposomes, and after lyophilization they contained 2.6 µg vit D3/mg liposomes and 0.8 µg vit B12/mg liposomes. Lyophilized liposomes showed water activity of 0.264 and 0.225, and 3.92% e 3.74 % of moisture para Lipoid S45 and Phospholipon 90G, respectively. The results show that lyophilized liposomes coencapsulating vitamins D3 and B12 are feasible to be produced and to be incorporated in food products in a near future.