Production and stability of food-grade liposomes containing microbial carotenoids from Rhodotorula mucilaginosa

Abstract

We demonstrated the technical feasibility of obtaining carotenoids-loaded liposomes from soybean lecithins using an ethanol injection technique. We evaluated the influence of three lecithin-types with different phosphatidylcholine content and microbial carotenoids produced by yeast Rhodotorula mucilaginosa on liposome properties. The liposomal systems were characterized by average hydrodynamic diameter, polydispersity index, ζ-potential, and stability under different pH and heat temperature conditions commonly observed in food processing. The lecithin type and concentration used to produce liposomes significantly influence the hydrodynamic diameter, polydispersity index, and ζ-potential. In general, we observed the presence of liposomes with diameters ranging from 150 to 221 nm and a polydispersity index of approximately 0.300 when Lipoid S45 was used. The incorporation of microbial carotenoids promoted a significant increase in hydrodynamic diameter and ζ-potential, while carotenoid-loaded liposomes showed a lower polydispersity index. The carotenoid-loaded liposomes submitted to pH 3 presented a visual phase separation, while liposomes submitted at 70 °C for 15 min showed degradation of carotenoids equal to control assay (without treatment). We concluded that it is possible to incorporate microbial carotenoids in food-grade liposomal systems, allowing for further studies aimed at their application as an encapsulating and/or delivery system to be used in aqueous food products.